bluuebunny/crossref_metadata_2025_split huggingface dataset:
CO‐Free Enantioselective Hydroformylation of Functionalised Alkenes: Using a Dual Catalyst System to Give Improved Selectivity and Yield
Authors: Pittaway Rachael , Dingwall Paul , Fuentes José. A. , Clarke Matthew. L. 
Published: July 2019

AbstractThe scope of carbon monoxide‐free Asymmetric Transfer HydroFormylation (ATHF) procedures using a highly active single catalyst system derived from 1,2‐bis‐((2,5)‐diphenylphospholano)ethane as chiral ligand has been studied. This reveals some highly successful reactions, but also significant limitations. The development of a new protocol in which a catalyst for formaldehyde decomposition to CO and H2 is combined with the catalyst of choice for the subsequent asymmetric hydroformylation is described. This enables ATHF reactions that were problematic to be significantly improved. The new method has been used in the synthesis of several key precursors to biologically active molecules.magnified image
Potential occupational and respiratory hazards in a Minnesota cannabis cultivation and processing facility
Authors: Couch James R. , Grimes George R. , Wiegand Douglas M. , Green Brett J. , Glassford Eric K. , Zwack Leonard M. , Lemons Angela R. , Jackson Stephen R. , Beezhold Donald H. 
Published: July 2019

AbstractBackgroundCannabis has been legalized in some form for much of the United States. The National Institute for Occupational Safety and Health (NIOSH) received a health hazard evaluation request from a Minnesota cannabis facility and their union to undertake an evaluation.MethodsNIOSH representatives visited the facility in August 2016 and April 2017. Surface wipe samples were collected for analysis of delta‐9 tetrahydrocannabinol (Δ9‐THC), delta‐9 tetrahydrocannabinol acid (Δ9‐THCA), cannabidiol, and cannabinol. Environmental air samples were collected for volatile organic compounds (VOCs), endotoxins (limulus amebocyte lysate assay), and fungal diversity (NIOSH two‐stage BC251 bioaerosol sampler with internal transcribed spacer region sequencing analysis).ResultsSurface wipe samples identified Δ9‐THC throughout the facility. Diacetyl and 2,3‐pentanedione were measured in initial VOC screening and subsequent sampling during tasks where heat transference was greatest, though levels were well below the NIOSH recommended exposure limits. Endotoxin concentrations were highest during processing activities, while internal transcribed spacer region sequencing revealed that the Basidiomycota genus, Wallemia, had the highest relative abundance.ConclusionsTo the authors’ knowledge, this is the first published report of potential diacetyl and 2,3‐pentanedione exposure in the cannabis industry, most notably during cannabis decarboxylation. Endotoxin exposure was elevated during grinding, indicating that this is a potentially high‐risk task. The findings indicate that potential health hazards of significance are present during cannabis processing, and employers should be aware of potential exposures to VOCs, endotoxin, and fungi. Further research into the degree of respiratory and dermal hazards and resulting health effects in this industry is recommended.
Bowl Inversion in an Exo‐type Supramolecule in the Solid State
Authors: Liu Yu‐Min , Huang Yu‐Qian , Liu Shun‐He , Chen Dandan , Tang Chun , Qiu Zhen‐Lin , Zhu Jun , Tan Yuan‐Zhi 
Published: July 2019

AbstractBowl inversion is a unique property of buckybowls. The polarity and assembly configuration of buckybowls are reversed after bowl inversion. So far, this unique phenomenon has been studied in solution and on surface, but not in solid state due to spatial constraint. Now a series of exo‐type supramolecular assemblies of trithiasumanene and nanographene are investigated. Tuning the electron density of the nanogaphene component was found to directly affect the binding constant of the complex. Reversible bowl inversion in the solid state was then successfully achieved by subjecting the trithiasumanene–nanographene assembly with the weakest binding strength to repeated heating–cooling cycles, which was unambiguously observed by single crystal X‐ray diffraction.
Formulierung von Elektrolyten mit gemischten Lithiumsalzen für Lithium‐Batterien
Authors: Xu Gaojie , Shangguan Xuehui , Dong Shanmu , Zhou Xinhong , Cui Guanglei 
Published: July 2019

AbstractDurch einfaches Mischen verschiedener Lithiumsalze im Elektrolyten werden Gemischtsalz‐Elektrolyte formuliert, um einen synergistischen Effekt zu bewirken. Auf dem Gebiet der Lithium‐Batterien der nächsten Generation wurden große Fortschritte mit Gemischtsalz‐Elektrolyten erzielt. In diesem Aufsatz wird die Entwicklung derartiger Gemischtsalz‐Elektrolyten näher ausgeführt. Die Ziele der Formulierung von Gemischtsalz‐Elektrolyten für Lithium‐Batterien werden zusammengefasst: Verbesserung der thermischen Stabilität (Sicherheit), Verhindern der Korrosion der Aluminiumfolie des Kathoden‐Stromkollektors, Steigerung der Leistung über einen breiten Temperaturbereich (oder bei niedrigen oder hohen Temperaturen), Bildung günstiger Grenzflächenschichten an beiden Elektroden, Schützen der Lithium‐Metall‐Anode, Erreichen einer hohen Ionenleitfähigkeit usw. Darüber hinaus diskutieren wir wesentliche Aspekte bei der Formulierung von Gemischtsalz‐Elektrolyten für Lithium‐Batterien.
A Bio‐Inspired Structurally‐Responsive and Polysulfides‐Mobilizable Carbon/Sulfur Composite as Long‐Cycling Life Li−S Battery Cathode
Authors: Cheng Mengying , Liu Jinyun , Zhang Haikuo , Han Tianli , Zhang Min , Cheng Dong , Zhai Muheng , Zhou Ping , Li Jinjin 
Published: July 2019

AbstractHigh energy density Li−S battery has attracted wide attention because of its promising application in long driving‐range electric vehicles. However, the shuttle effect of polysulfides, electrical insulation and volume‐change of sulfur, remain great challenges. Herein, inspired from a natural mimosa pudica structure, we present a novel nanocomposite which consists of a mimosa pudica‐structured carbon matrix coating with sulfur. The biomimetic configuration is able to structurally‐respond to the volume‐change of sulfur during charge/discharge; and the carbon matrix provides a good conductivity for rapid electron transfer. The carbon/sulfur composite‐based Li−S batteries exhibit a good electrochemical performance including a stable capacity after 1000 cycles, along with a Coulombic efficiency as high as 99.6 %, and an excellent rate‐performance even after three rounds of measurements. In addition, the density function theory modeling is investigated, which confirms the adsorption effect of carbon towards the polysulfides including Li2S4, Li2S6, and Li2S8, enabling a long‐term cycling stability.
Recent Advances in the Chemistry of Heavier Group 14 Enolates
Authors: Haas Michael 
Published: July 2019

AbstractRecently heavier Group 14 enolates showed their importance and applicability in a broad range of chemical transformations. They were found to be key intermediates during the synthesis of photoinitiators, as well as during the formation of complex silicon frameworks. This Minireview presents general strategies towards the synthesis of heavier Group 14 enolates (HG 14 enolates). Structural properties, as well as their spectroscopic behavior are outlined. This study may aid future development in this research area.
Formation of Transient Anionic Metal Clusters in Palladium/Diene‐Catalyzed Cross‐Coupling Reactions
Authors: Kolter Marlene , Koszinowski Konrad 
Published: July 2019

AbstractDespite their considerable practical value, palladium/1,3‐diene‐catalyzed cross‐coupling reactions between Grignard reagents RMgCl and alkyl halides AlkylX remain mechanistically poorly understood. Herein, we probe the intermediates formed in these reactions by a combination of electrospray‐ionization mass spectrometry, UV/Vis spectroscopy, and NMR spectroscopy. According to our results and in line with previous hypotheses, the first step of the catalytic cycle brings about transmetalation to afford organopalladate anions. These organopalladate anions apparently undergo SN2‐type reactions with the AlkylX coupling partner. The resulting neutral complexes then release the cross‐coupling products by reductive elimination. In gas‐phase fragmentation experiments, the occurrence of reductive eliminations was observed for anionic analogues of the neutral complexes. Although the actual catalytic cycle is supposed to involve chiefly mononuclear palladium species, anionic palladium nanoclusters [PdnR(DE)n]−, (n=2, 4, 6; DE=diene) were also observed. At short reaction times, the dinuclear complexes usually predominated, whereas at longer times the tetra‐ and hexanuclear clusters became relatively more abundant. In parallel, the formation of palladium black pointed to continued aggregation processes. Thus, the present study directly shows dynamic behavior of the palladium/diene catalyst system and degradation of the active catalyst with increasing reaction time.
CFD study on the flow distribution of an annular multi‐hole nozzle
Authors: He Yu , Sun Zhibin , Shen Baojun , Guo Fang , Yang Yili , Zhan Xiaobin , Li Xiwen 
Published: July 2019

AbstractAnnular multi‐hole nozzles are commonly used to disperse one or more types of material in chemical processing, agricultural irrigation, firefighting, and so on. In this study, the LES (large eddy simulation) method combined with the VOF (volume of fluid) model was employed to investigate the impacts of inlet volume flow rate, hole diameter, and distance downstream of nozzle on the flow distribution of the nozzle. To quantify the uniformity of the flow distribution, the non‐uniformity parameter, wetted area, and uniformity index were introduced. The sprays ejected from the nozzle are separated into two modes in accordance with their structure, namely partially impinging sprays (PIS) and fully impinging sprays (FIS). Compared with the three other types of nozzles investigated in this study, the nozzles with a 400 μm hole diameter can achieve the most uniform flow distribution of the nozzle outlet. In addition, the nozzle with larger holes and a higher inlet volume flow rate can easily achieve a large wetted area. However, the nozzle with smaller holes and a relatively low inlet volume flow rate is more inclined to achieve a uniform flow distribution. The larger the inlet volume flow rate, the larger the holes that should be adopted to achieve a relatively uniform flow distribution.
An Angle on MK2 Inhibition—Optimization and Evaluation of Prevention of Activation Inhibitors
Authors: Hedström Ulf , Norberg Monica , Evertsson Emma , Lever Sarah R. , Munck af Rosenschöld Magnus , Lönn Hans , Bold Peter , Käck Helena , Berntsson Pia , Vinblad Johanna , Liu Jianming , Welinder Anette , Karlsson Johan , Snijder Arjan , Pardali Katerina , Andersson Ulf , Davis Andrew M. , Mogemark Mickael 
Published: July 2019

AbstractThe mitogen‐activated protein kinase p38α pathway has been an attractive target for the treatment of inflammatory conditions such as rheumatoid arthritis. While a number of p38α inhibitors have been taken to the clinic, they have been limited by their efficacy and toxicological profile. A lead identification program was initiated to selectively target prevention of activation (PoA) of mitogen‐activated protein kinase‐activated protein kinase 2 (MK2) rather than mitogen‐ and stress‐activated protein kinase 1 (MSK1), both immediate downstream substrates of p38α, to improve the efficacy/safety profile over direct p38α inhibition. Starting with a series of pyrazole amide PoA MK2 inhibitor leads, and guided by structural chemistry and rational design, a highly selective imidazole 9 (2‐(3′‐(2‐amino‐2‐oxoethyl)‐[1,1′‐biphenyl]‐3‐yl)‐N‐(5‐(N,N‐dimethylsulfamoyl)‐2‐methylphenyl)‐1‐propyl‐1H‐imidazole‐5‐carboxamide) and the orally bioavailable imidazole 18 (3‐methyl‐N‐(2‐methyl‐5‐sulfamoylphenyl)‐2‐(o‐tolyl)imidazole‐4‐carboxamide) were discovered. The PoA concept was further evaluated by protein immunoblotting, which showed that the optimized PoA MK2 compounds, despite their biochemical selectivity against MSK1 phosphorylation, behaved similarly to p38 inhibitors in cellular signaling. This study highlights the importance of selective tool compounds in untangling complex signaling pathways, and although 9 and 18 were not differentiated from p38α inhibitors in a cellular context, they are still useful tools for further research directed to understand the role of MK2 in the p38α signaling pathway.
Growth morphologies and plausible stressors ruling the formation of Late Pleistocene lacustrine carbonate buildups in the Maquinchao Basin (Argentina)
Authors: Eymard Inès , Bilmes Andrés , Alvarez María del Pilar , Feo Rodrigo , Hunger Gabriel , Vasconcelos Crisogono , Arizteguí Daniel 
Published: July 2019

AbstractIn a seminal paper regarding the mechanisms of carbonate stromatolite formation, Ginsburg (1991, Controversies in Modern Geology, pp. 25–36) emphasized the need to question the relative role of microbes versus environment in their formation. The Maquinchao Basin is a continental lacustrine system in southern Argentina. It provides an ideal site to study carbonate buildups, the role of microbes and environmental stressors in their development and their implications in palaeoenvironmental reconstructions. Presently, the basin encompasses two lakes (Carri Laufquen Grande and Carri Laufquen Chica) joined by the ephemeral Maquinchao River. Fossil microbialites are found south and southwest of the largest lake. Preferential areas of development for fossil microbialites have been mapped using a high‐resolution differential Global Positioning System. Outcrops are located between 820 and 830 m elevation, higher than actual lake levels and the Maquinchao River where living microbialites have been observed. Field data along with microscopical observations and X‐ray diffraction analyses have revealed a heterogeneity in both distribution and macro‐morphotypes since carbonate buildups display different morphologies such as crust, columns, open flower‐like, rounded and ellipsoids. Conversely, on the meso and micro‐scale they show more homogeneous morphologies including laminations and shrubs. These microbial buildups are associated with basaltic substrates of variable size from pebbles to boulder. The homogeneity in meso and micro‐structures argue in favour of stable intrinsic parameters (i.e. microbial communities) whereas the variable macro‐morphotypes indicate changing extrinsic constraints such as steepness, energy and turbidity. The occurrence of distinctive morphotypes in buildups separated by outcrop and topography suggest that the Maquinchao microbialites are indicative of a former larger lake. Thus, the Maquinchao microbial buildups are a valuable proxy for water‐level evolution and therefore palaeoenvironmental reconstructions. They can be further used to interpret the apparently random distribution of morphological types and extension of microbialites in the geological past.
Shifts in phenological mean and synchrony interact to shape competitive outcomes
Authors: Carter Shannon K. , Rudolf Volker H. W. 
Published: July 2019

AbstractClimate change–induced phenological shifts are ubiquitous and have the potential to disrupt natural communities by changing the timing of species interactions. Shifts in first and/or mean phenological date are well documented, but recent studies indicate that shifts in synchrony (individual variation around these metrics) can be just as common. However, we know little about how both types of phenological shifts interact to affect species interactions and communities. Here, we experimentally manipulated the hatching phenologies of two competing species of larval amphibians to address this conceptual gap. Specifically, we manipulated the relative mean hatching time (early, same, or late relative to competitor) and population synchrony (high, medium, or low levels of variation around the mean) in a full 3 × 3 factorial design to measure independent and interactive effects of phenological mean and population phenological synchrony on competitive outcomes. Our results indicate that phenological synchrony within a population strongly influences intraspecific competition by changing the density of individuals and relative strength of early‐ vs. late‐arriving individuals. Individuals from high‐synchrony populations competed symmetrically, whereas individuals from low‐synchrony populations competed asymmetrically. At the community scale, shifts in population phenological synchrony interact with shifts in phenological mean to affect key demographic rates (survival, biomass export, per capita mass, and emergence timing) strongly. Furthermore, changes in mean timing of species interactions altered phenological synchrony within a population at the next life stage, and phenological synchrony at one life stage altered the mean timing of the next life stage. Thus, shifts in phenological synchrony within populations cannot only alter species interactions, but species interactions in turn can also drive shifts in phenology.
Research of the combined reforming of bio‐oil model compound for hydrogen production
Authors: Xu Qingli , Feng Peng , Huang Kai , Xin Shanzhi , Wei Ting , Liao Lifang , Yan Yongjie 
Published: July 2019

AbstractThe combination of steam and CO2 reforming of bio‐oil is proposed in this article. The combined reforming can make good use of the advantages of steam reforming and CO2 reforming. The results indicate that H2 yield, potential H2 yield, and H2/CO were 60.23, 81.97, and 2.77%, respectively, at the condition of 700°C and bio‐oil:CO2:H2O = 1:0.5:1.5. Bio‐oil:CO2:H2O has a significant effect on the H2 yield, potential H2 yield, and H2/CO in the process of combined reforming. A different ratio of H2/CO can be obtained by adjusting the proportion of bio‐oil:CO2:H2O, which can meet different industry requirements. The results of X‐ray diffraction and scanning electron microscope analyses indicate that the catalyst deactivation was the result of a combination of carbon deposition and Ni grain sintering, and the carbon deposition was a main reason for the catalyst deactivation.
Fetal hypoxia and hyperglycemia in the formation of phenytoin‐induced cleft lip and maxillary hypoplasia
Authors: Ritchie Helen E. , Oakes Diana , Farrell Emma , Ababneh Deena , Howe Andrew 
Published: July 2019

AbstractObjectivePhenytoin exposure during the first trimester of pregnancy increases the risk of maxillary hypoplasia and cleft lip. The etiology of phenytoin embryopathy is unknown. Interestingly, phenytoin is also known to induce hyperglycemia in humans as well as rats. This study uses a rat model of fetal phenytoin syndrome to examine the role of hyperoxia, hyperglycemia, and arachidonic acid deficiency in the development of cleft lip and maxillary hypoplasia.MethodsPregnant rats were dosed with phenytoin during the critical period of lip development (day 11 of pregnancy) with or without supplemental oxygen, insulin, or arachidonic acid. The fetuses from all studies were examined at term.ResultsThe frequency of cleft lip and maxillary hypoplasia was reduced by treating dams at the time of phenytoin exposure with either increased oxygen or insulin. However, in fetuses from phenytoin‐treated dams dosed with arachidonic acid, the incidence of severe lip deformities remained the same although there was an increase in normal and mildly affected fetuses. Interestingly, this occurred in embryos from hyperglycemic dams.SignificanceTogether, the results from these experiments suggest phenytoin‐induced malformations may be a multifactorial process as malformations were not solely linked to a hyperglycemic state of the dam.
Soil particle size distribution and induced soil carbon transport by ephemeral gully erosion in Mediterranean mountain arable land
Authors: Quijano Laura , Kuhn Nikolaus J. , Navas Ana 
Published: July 2019

AbstractIn Mediterranean mountain agroecosystems, soil erosion associated with the development of ephemeral gullies is a common environmental problem that contributes to a loss of nutrient‐rich topsoil. Little is known about the influence of ephemeral gully erosion on particle size distribution and its effect on soil organic (SOC) and inorganic (SIC) carbon among different sized soil particles in agricultural soils. In this study, laboratory tests were conducted using velocity settling tube experiments to examine the effects of erosion on sediment particle size distributions from an incised ephemeral gully, associated with an extreme event (235 mm). We also consider subsequent deposition on an alluvial fan in order to assess the distribution of SOC and SIC concentrations and dissolved carbon before and after the extreme event. Soil fractionation was carried out on topsoil samples (5 cm) collected along an ephemeral gully in a cultivated field, located in the lower part of a Mediterranean mountain catchment. The results of this study showed that the sediment transported downstream by runoff plays a key role in the particle size distribution and transportability of soil particles and associated carbon distribution in carbonate rich soils. The eroding sediment is enriched in clay and silt‐sized particles at upslope positions with higher SOC contents and gradually becomes coarser and enriched in SIC at the end of the ephemeral gully because the finest particles are washed‐out of the study field. The extreme event was associated with an accumulation of dissolved organic carbon at the distal part of the depositional fan. Assessment of soil particle distribution using settling velocity experiments provides basic information for a better understanding of soil carbon dynamics in carbonate rich soils. Processes of soil and carbon transport and relationships between soil properties, erodibility and aggregate stability can be helpful in the development of more accurate soil erosion models. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.
Cytogenomic array detects a subset of myelodysplastic syndrome with increased risk that is invisible to conventional karyotype
Authors: Choi Sarah M. , Van Norman Steven B. , Bixby Dale L. , Shao Lina 
Published: July 2019

AbstractConventional karyotyping is essential standard practice in the initial evaluation of myelodysplastic syndrome (MDS) and is the most impactful single component of the Revised International Prognostic Scoring System (IPSS‐R). While single nucleotide polymorphism array (SNP‐A) has demonstrated the ability to detect chromosomal defects with greater sensitivity than conventional karyotype, widespread adoption is limited by the unknown additional prognostic impact of SNP‐A analysis. Here, we investigate the significance of additional SNP‐A abnormalities in the setting of MDS and demonstrate differences in survival of patients with additional abnormalities, even those initially characterized as relatively lower risk either by cytogenetic score or IPSS‐R. Our findings identify specific abnormalities, particularly KMT2A partial tandem duplication, that are invisible to conventional karyotype and potentially contribute to the poor prognosis of MDS patients. Furthermore, these results demonstrate the added value of SNP‐A analysis in identifying patients who may benefit from more aggressive therapy, particularly those who would otherwise be classified into lower risk categories.