bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel dissolution‐precipitation method for high‐efficiency separation of oil‐wetted oil sands
Authors: Hu Pengcheng , Chai Ruimin , Liu Quanyou , Wang Junlin , Zhou Shu‐Feng 
Published: November 2019

AbstractDissolution‐precipitation is a novel high‐efficiency method for separating oil‐wetted oil sands. Four dissolving agents and three precipitating agents were studied to select the optimal combination. Results showed that N,N‐dimethylcyclohexylamine (DMCHA) and methanol were the optimal dissolving and precipitating agents, respectively. The chemical group compositions, element content, and H/C atom ratio of bitumen separated by DMCHA‐methanol were analyzed, and the optimal conditions for oil sands separation were determined, under which the bitumen recovery reached 96.4%. After six separation cycles with DMCHA‐methanol, the bitumen recovery remained above 93%.
Palladium‐Catalyzed Asymmetric [4+3]‐Cyclization Reaction of Fused 1‐Azadienes with Amino‐trimethylenemethanes: Highly Stereoselective Construction of Chiral Fused Azepines
Authors: Kumari Prathibha , Liu Weiwei , Wang Cheng‐Jie , Dai Jun , Wang Mei‐Xin , Yang Qi‐Qiong , Deng Yu‐Hua , Shao Zhihui 
Published: November 2019

Summary of main observation and conclusionA Pd‐catalyzed asymmetric aromative [4+3]‐cyclization reaction of amino‐trimethylenemethanes (TMM, 1,3‐dipoles) with fused 1‐azadienes has been developed. This method enables access to the synthetically importance and biologically active benzofuran fused azepines and indeno‐azepines in excellent efficiency and stereoselectivity (up to 95% yield, 99% ee, >19 : 1 dr).
An Octacationic [2]Catenane Formed by Oxime Condensation: A Bistable Molecular Switch
Authors: Wang Cai‐Yun , Wu Guangcheng , Zhu Jiaqi , Jiao Tianyu , Zhang Yang , Li Hao 
Published: November 2019

AbstractOxime condensation as well as template‐directed synthesis based on radical‐pairing interactions were used in the synthesis of an octacationic [2]catenane in 20 % yield. The [2]catenane consists of two identical mechanically interlocked tetracationic macrocyclic components. Each of the ring components contains two dicationic bipyridinium (BIPY2+) functions. The structure of the [2]catenane was fully characterized by NMR spectroscopy, mass spectrometry, as well as X‐ray crystallography. In the oxidized state, the [2]catenane exists in a co‐conformation where its four BIPY2+ units are located as far as possible from each other. Upon reduction of BIPY2+ into the radical state, namely BIPY+., we propose that the [2]catenane undergoes mechanical movement, driven by radical pairing interactions between these radical building blocks. The redox‐stimulated switching behavior of this [2]catenane was confirmed by electrochemistry, UV‐Vis‐NIR absorption spectroscopy, and 1H NMR spectroscopy.
Per- and Polyfluoroalkyl Substances (PFAS): Anglers May Be Exposed to Harmful Chemicals in Their Catch
Authors: Fraley Kevin M , Fraley Heather N , Arthur Donald , Walther Eric J 
Published: November 2019

Abstract
In this review, we focus on per- and polyfluoroalkyl substances (PFAS), synthetic compounds used for a variety of applications, including firefighting foam and manufacturing. Recently, researchers have linked human exposure to PFAS to negative health effects. Hundreds of communities are affected by PFAS contamination, which has raised awareness about the toxicity of these chemicals. Most work has focused on characterizing dangers to humans, and the effects of PFAS on the environment are under-studied. PFAS contamination of surface water can result in bioaccumulation and biomagnification in fishes. Studies have linked PFAS to lower fitness in fishes, and anglers who consume wild fish can have higher exposure to PFAS compared to the general population. These chemicals remain largely unregulated and the public has been unaware of the extent of contamination and their risk to human health until recently. We review known PFAS contamination of wild-caught fish, and their possible health risk through angler exposure in the Fairbanks North Star Borough, Alaska. The conclusions and recommendations from the case study can be applied to and are useful for PFAS-contaminated communities nationwide.
Clay source and firing temperatures of Roman ceramics: A case study from Plovdiv, Bulgaria
Authors: Lesigyarski Deyan , Jordanova Neli , Kostadinova‐Avramova Maria , Bozhinova Elena 
Published: November 2019

AbstractDuring urgent archaeological excavations in the city of Plovdiv (South Bulgaria), a Roman pottery workshop was found, including several dome kilns, ceramic sherds, and a large clay deposit incorporating yellow and gray clay layers. A set of the ceramic specimens (kitchenwares and tablewares) and raw clay samples were investigated using a portable device for X‐ray fluorescence and laboratory equipment for magnetic measurements, aiming to provide specific information about the origin and firing technology of the pottery. Despite significant difference in calcium content between local raw clay and pottery samples, we conclude that local natural clay sources were used and the initial stages of production involved clay purification, although we cannot rule out the procurement of more distant clay sources. Magnetic susceptibility testing allowed for determination of the maximum firing temperatures, showing that the pottery were fired predominantly at 780°C, with some samples being fired at temperatures up to 860°C. Magnetic analyses show that kitchenwares were fired under more uniform conditions than the tablewares, which undoubtedly reflected in the quality of the vessels produced.
Parcellation influence on the connectivity‐based structure–function relationship in the human brain
Authors: Messé Arnaud 
Published: November 2019

AbstractOne of the fundamental questions in neuroscience is how brain structure and function are intertwined. MRI‐based studies have demonstrated a close relationship between the physical wiring of the brain (structural connectivity) and the associated patterns of synchronization (functional connectivity). However, little is known about the spatial consistency of such a relationship and notably its potential dependence on brain parcellations. In the present study, we performed a comparison of a set of state‐of‐the‐art group‐wise brain atlases, with various spatial resolutions, to relate structural and functional connectivity derived from high quality MRI data. We aim to investigate if the definition of brain areas influences the relationship between structural and functional connectivity. We observed that there is a significant effect of brain parcellations, which is mainly driven by the number of areas; there are mixed differences in the SC–FC relationship when compared to purely random parcellations; the influence of the number of areas cannot be attributed solely to the reliability of the connectivity estimates; and beyond the influence of the number of regions, the spatial embedding of the brain (distance effect) can explain a large portion of the observed relationship. As such the choice of a brain parcellation for connectivity analyses remains most likely a matter of convenience.
The heterogeneous causal effects of neonatal care: a model of endogenous demand for multiple treatment options based on geographical access to care
Authors: Mújica‐Mota Rubén E. , Landa Paolo , Pitt Martin , Allen Mike , Spencer Anne 
Published: November 2019

AbstractNeonatal units in the UK are organised into three levels, from highest Neonatal Intensive Care Unit (NICU), to Local Neonatal Unit (LNU) to lowest Special Care Unit (SCU). We model the endogenous treatment selection of neonatal care unit of birth to estimate the average and marginal treatment effects of different neonatal designations on infant mortality, length of stay and hospital costs. We use prognostic factors, survival and hospital care use data on all preterm births in England for 2014–2015, supplemented by national reimbursement tariffs and instrumental variables of travel time from a geographic information system. The data were consistent with a model of demand for preterm birth care driven by physical access. In‐hospital mortality of infants born before 32 weeks was 8.5% overall, and 1.2 (95% CI: −0.7, 3.2) percentage points lower for live births in hospitals with NICU or SCU compared to those with an LNU according to instrumental variable estimates. We find imprecise differences in average total hospital costs by unit designation, with positive unobserved selection of those with higher unexplained absolute and incremental costs into NICU. Our results suggest a limited scope for improvement in infant mortality by increasing in‐utero transfers based on unit designation alone.
Ensuring Taiwan patient safety culture survey is free from differential item functioning
Authors: Lee Wui‐Chiang , Han Su‐Ha , Jeong Heon‐Jae 
Published: November 2019

SummaryBackgroundDifferential item functioning (DIF) means the interference of some demographic characteristic or grouping of the tight relationship between trait levels. DIF threatens precise interpretations of survey results and makes them unreliable. The aim of this study was to examine whether the succinct version of Taiwan Patient Safety Culture (TPSC‐S) survey is free from DIF and to mitigate its impact if needed.MethodsThe TPSC‐S survey results of 2964 respondents in a public hospital in Taiwan were analyzed. The existence, type, and effect size of DIF were examined for each TPSC‐S item using a proportional‐odds logistic regression method between characteristic groups, including gender, work experience, job types, management roles, employment status, and safety reporting experiences.ResultsThe study results revealed that several items of TPSC‐S showed statistically significant DIF between characteristic groups. Nevertheless, the magnitude of these DIF was small, and their influence to TPSC‐S survey was not significant. The domain‐level DIF impact was completely insignificant for all characteristic groups.ConclusionThis study revealed that the 24‐item TPSC‐S survey was free from DIF in six characteristic groups. The difference in survey scores between groups stems from the real difference that hospital safety managers want to measure.
A generalization of Heffter arrays
Authors: Costa Simone , Morini Fiorenza , Pasotti Anita , Pellegrini Marco Antonio 
Published: November 2019

AbstractIn this paper, we define a new class of partially filled arrays, called relative Heffter arrays, that are a generalization of the Heffter arrays introduced by Archdeacon in 2015. Let be a positive integer, where divides , and let be the subgroup of of order . A Heffter array over relative to is an partially filled array with elements in such that (a) each row contains filled cells and each column contains filled cells; (b) for every , either or appears in the array; and (c) the elements in every row and column sum to . Here we study the existence of square integer (i.e., with entries chosen in and where the sums are zero in ) relative Heffter arrays for , denoted by . In particular, we prove that for , with , there exists an integer if and only if one of the following holds: (a) is odd and ; (b) and is even; (c) . Also, we show how these arrays give rise to cyclic cycle decompositions of the complete multipartite graph.
Ectopic expression of CYP24A1 circular RNA hsa_circ_0060927 in uterine leiomyomas
Authors: Fazeli Elnaz , Piltan Samira , Sadeghi Hossein , Gholami Milad , Azizi‐Tabesh Ghasem , Yassaee Fakhrolmolook , Mirfakhraie Reza 
Published: November 2019

AbstractBackgroundAs a novel class of non‐coding RNAs, the role of circular RNAs (circRNAs) in tumor biogenesis and progression has been proved in a number of human tumors; however, up to now, the relation between circRNAs and uterine leiomyomas (ULM) remains unclear.MethodsIn this study, we have estimated the expression level of CYP24A1 hsa_circ_0060927 in uterine leiomyoma and adjacent tissues considering the mediator complex subunit 12 gene (MED12) mutation profile by quantitative real‐time polymerase chain reaction (qRT‐PCRs).ResultsUsing Sanger sequencing method, somatic mutations in the MED12 exon 2 were detected in 14 (35.90%) ULM samples, including 10 (71.43%) missense mutations and 4 (28.57%) in‐frame deletions. Our results revealed that hsa_circ_0060927 was ectopically expressed in 33.33% of ULM tissues; although, this expression was independent of the MED12 mutation profile in the ULM samples.ConclusionsPresent results provide primary evidence for the role of circular RNAs in the leiomyoma development; however, further studies are essential to confirm the importance of these molecules as potential biomarkers for diagnosis and/or prognosis in ULM.
Effect of cavosurface angle beveling on the exposure angle of enamel prisms in different cavity sizes
Authors: Meurer José C. , Rizzante Fabio A. P. , Maenossono Rafael M. , França Fabiana M. G. , Bombonatti Juliana F. S. , Ishikiriama Sérgio K. 
Published: November 2019

AbstractThe quality of the micromechanical retention between the enamel prisms exposed through acid etching and adhesive system can be influenced by the relationship between the angle of the exposed enamel prisms and the external surface/restorative material. Therefore, the aim of the present study was to determine the influence of the enamel cavosurface beveling in different cavity sizes on the angle relation between enamel prisms and the restorative material. For this research, 30 human permanent molars were used and divided into three groups according the isthmus aperture of class I cavities (1/4, 1/3, and 1/2 of the intercuspal distance). Cavosurface angle beveling was performed in each tooth buccal or palatal/lingual side, and a resin composite restoration was placed. Each restored tooth was sectioned in buccal/palatal direction followed by analysis in scanning electron microscope. Means of the angles observed between enamel prisms and the restorative material were registered and statistically analyzed by Kruskal‐Wallis test. Results showed higher mean angle values for beveled groups when comparing with the values observed in the unbeveled margins (p < .05) regardless of the isthmus aperture, being 1/4 (beveled = 48.36°; unbeveled = 20.71°), 1/3 (beveled = 39.75°; unbeveled = 29.15°), and 1/2 (beveled = 37.02°; unbeveled = 26.34°). It was also observed that in some unbeveled cavities, there were the presence of laterally exposed enamel prisms (0°), mainly in more conservative cavities. It was concluded that the presence of higher angles values occurred in the samples with beveled margins, without presence of laterally exposed enamel prisms.
Hydrophobically Modified Alkali Soluble Emulsion Polymers: Literature Review
Authors: Vitiello Rosa , Rossano Carmelina , Russo Krauss Irene , D'Errico Gerardino , Di Serio Martino 
Published: November 2019

AbstractIn recent years, interest in the class of water‐soluble polymers—hydrophobically modified alkali soluble emulsion (HASE)—has increased on a surprising scale. With respect to other associative polymers, they have several advantages in terms of cost and ease of handling and utilization. In addition, unlike the solvent‐based formulations, these water‐soluble systems do not contain volatile solvents and hence do not contribute to environmental problems. In solutions, HASE polymers form a transient network through molecular associations between the hydrophobic groups. Due to these hydrophobic interactions, they have been increasingly used as rheology modifiers for various applications, such as paints, cosmetics, and personal care and paper coating products. These associative polymers have an architectural richness that allows the fine tuning of several physicochemical properties, and their optimal use requires controlling polymer concentration, molecular weight, size of the hydrophobic groups, and characteristics of the polymeric backbone. We give an overview of several studies on HASE polymers reported in the literature, focusing on the molecular structure, the synthetic methodologies, and—more specifically—on the factors that affect the rheology of their aqueous mixtures. As a general rule for the optimal HASE design and formulative exploitation, we highlight that the hydrophobic hanging groups are responsible for the rheological changes in the liquid phase, while the steric hindrance of the polymeric backbone and of the hydrophobic groups causes the stiffness.
Diffusion Kurtosis Imaging and Intravoxel Incoherent Motion in Differentiating Nasal Malignancies
Authors: Xiao Zebin , Tang Zuohua , Zheng Chunquan , Luo Jianfeng , Zhao Keqing , Zhang Zhongshuai 
Published: November 2019

Objectives/HypothesisTo evaluate the usefulness of diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) in the differentiation of sinonasal malignant tumors (SNMTs) with different histological types.Study DesignRetrospective observational and diagnostic study.MethodsSixty‐five patients with SNMTs who underwent DKI and IVIM were enrolled in this retrospective study, including 27 squamous cell carcinomas (SCCs), 13 olfactory neuroblastomas (ONBs), 14 malignant melanomas (MMs) and 11 lymphomas. The kurtosis (K) and diffusion coefficient (Dk) from DKI and the pure diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and the product ofD*andf(f∙D*) from IVIM were measured. Kruskal‐Wallis and Dunn multiple comparison tests with Bonferroni correction, receiver operating characteristic curve, and logistic regression analyses were used for statistical analysis.ResultsLymphomas demonstrated the highest K values but lowest Dk,D,D*,f, andf∙D*values among these four malignant tumors. ONBs exhibited high K values and MMs had highestD*,f, andf∙D*values. The cutoff value of ≤0.887 × 10−3mm2/sec forf∙D*provided a sensitivity, specificity, and an accuracy of 100%, 98.1%, and 98.5%, respectively, for differentiating lymphomas from the other three entities. The combination off∙D*andDvalues showed a sensitivity of 92.9% and a specificity of 92.5% for the discrimination of MMs from ONBs and SCCs. The K value was useful for differentiating ONBs from SCCs, with a threshold value of 0.942 (sensitivity, 84.6%; specificity, 63.0%).ConclusionsThe combined use of DKI and IVIM is helpful for differentiating among four histological types of SNMTs.Level of Evidence3Laryngoscope, 2019
Exploring temperature and precipitation impacts on harmful algal blooms across continental U.S. lakes
Authors: Ho Jeff C. , Michalak Anna M. 
Published: November 2019

AbstractClimate change is expected to impact the severity of harmful algal blooms in lakes and reservoirs through a number of mechanisms related to the influence of warming temperatures and changes to precipitation patterns. Evidence on the prevalence of individual mechanisms is lacking, however, with knowledge of many mechanisms restricted to studies of individual or small subsets of lakes. Here, we leverage over twelve hundred summertime lake observations from across the continental U.S. to explore evidence for the hypothesized risks from climate change attributable to specific mechanisms. Using a statistical model selection approach, we examine associations between temperature and precipitation variables and indicators of total phytoplankton abundance, species dominance, and toxicity. We find evidence in support of the hypotheses that summer temperatures drive total abundance, that the length of the summer drives cyanobacterial abundance, and that increased temperatures may reduce the observed toxicity of blooms in some cases. We find that nutrient concentrations are also likely to be impacted by lake warming, as increased temperatures are robustly associated with increased total phosphorus concentrations. Evidence for the impact of precipitation is mixed, however, as there is evidence to support that increased nutrient runoff from precipitation could support blooms but also that nutrient concentrations could be reduced through greater flushing due to precipitation. While statistical associations are not definitive evidence of formal mechanistic links, the geographic scale of the results is useful for identifying hypothesized mechanisms that are widespread across the continental U.S., and therefore for informing understanding of the influence of climate change.
Linking metagenomics to aquatic microbial ecology and biogeochemical cycles
Authors: Grossart Hans‐Peter , Massana Ramon , McMahon Katherine D. , Walsh David A. 
Published: November 2019

AbstractMicrobial communities are essential components of aquatic ecosystems through their contribution to food web dynamics and biogeochemical processes. Aquatic microbial diversity is immense and a general challenge is to understand how metabolism and interactions of single organisms shape microbial community dynamics and ecosystem‐scale biogeochemical transformations. Metagenomic approaches have developed rapidly, and proven to be powerful in linking microbial community dynamics to biogeochemical processes. In this review, we provide an overview of metagenomic approaches, followed by a discussion on some recent insights they have provided, including those in this special issue. These include the discovery of new taxa and metabolisms in aquatic microbiomes, insights into community assembly and functional ecology as well as evolutionary processes shaping microbial genomes and microbiomes, and the influence of human activities on aquatic microbiomes. Given that metagenomics can now be considered a mature technology where data generation and descriptive analyses are relatively routine and informative, we then discuss metagenomic‐enabled research avenues to further link microbial dynamics to biogeochemical processes. These include the integration of metagenomics into well‐designed ecological experiments, the use of metagenomics to inform and validate metabolic and biogeochemical models, and the pressing need for ecologically relevant model organisms and simple microbial systems to better interpret the taxonomic and functional information integrated in metagenomes. These research avenues will contribute to a more mechanistic and predictive understanding of links between microbial dynamics and biogeochemical cycles. Owing to rapid climate change and human impacts on aquatic ecosystems, the urgency of such an understanding has never been greater.
Which series are Hilbert series of graded modules over standard multigraded polynomial rings?
Authors: Katthän Lukas , Moyano‐Fernández Julio José , Uliczka Jan 
Published: November 2019

AbstractConsider a polynomial ring R with the ‐grading where the degree of each variable is a standard basis vector. In other words, R is the homogeneous coordinate ring of a product of n projective spaces. In this setting, we characterize the formal Laurent series which arise as Hilbert series of finitely generated R‐modules. We also provide necessary conditions for a formal Laurent series to be the Hilbert series of a finitely generated module with a given depth. In the bigraded case (corresponding to the product of two projective spaces), we completely classify the Hilbert series of finitely generated modules of positive depth.