bluuebunny/crossref_metadata_2025_split huggingface dataset:
Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions
Authors: Villegas‐Escobar Nery , Larsen (née Vilhelmsen) Mie Højer , Gutiérrez‐Oliva Soledad , Hashmi A. Stephen K. , Toro‐Labbé Alejandro 
Published: June 2017

AbstractIn this work, a detailed characterization was carried out of the ring‐closure mechanism of EPB (1‐ethynyl‐2‐(phenylethynyl)benzene) toward the 5‐exo‐dig and 6‐endo‐dig cyclization reactions, catalyzed by two Au–N‐heterocyclic carbene (NHC) moieties. It was found that the 5‐exo‐dig cyclization takes place with a slightly lower activation barrier and larger exothermicity compared to that of the 6‐endo‐dig cyclization, in agreement with the available experimental data. A phenomenological partition (structural and electronic) for rate constants computed using transition‐state theory and the reaction force analysis was used to shed light into the nature of the activation rate constant. It was found that rate constants are influenced by a strong structural component, which is larger for the 5‐exo‐dig cyclization due to the strain to form the five‐membered ring. On the other hand, the gold activation mechanism is evidenced by a σ‐ and π‐coordination of the Au−NHC moieties to the EPB substrate. It was found that differences in the σ‐coordination arise on the reaction path for the 5‐exo‐dig and 6‐endo‐dig cyclizations. Thus, in the 6‐endo‐dig cyclization the σ gold–EPB interaction is weakened as a consequence of the formation of the cationic aryl intermediate, while for the 5‐exo‐dig cyclization this interaction was found to be favored. Furthermore, although minor changes in the Au–EPB coordination occur on the reaction path, these bonds are formally established in the TS vicinity. Results support the concerted nature of the dual gold activation mechanism.
Target Identification of Kinase Inhibitor Alisertib (MLN8237) by Using DNA‐Programmed Affinity Labeling
Authors: Wang Dong‐Yao , Cao Yan , Zheng Le‐Yi , Chen Lang‐Dong , Chen Xiao‐Fei , Hong Zhan‐Ying , Zhu Zhen‐Yu , Li Xiaoyu , Chai Yi‐Feng 
Published: June 2017

AbstractAccurate identification of the molecular targets of bioactive small molecules is a highly important yet challenging task in biomedical research. Previously, a method named DPAL (DNA‐programmed affinity labeling) for labeling and identifying the cellular targets of small molecules and nucleic acids was developed. Herein, DPAL is applied for the target identification of Alisertib (MLN8237), which is a highly specific aurora kinase A (AKA) inhibitor and a drug candidate being tested in clinical trials for cancer treatment. Apart from the well‐established target of AKA, several potential new targets of MLN8237 were identified. Among them, p38 mitogen‐activated protein kinase (p38) and laminin receptor (LAMR) were validated to be implicated in the anticancer activities of MLN8237. Interestingly, these new targets were not identified with non‐DNA‐based affinity probes. This work may facilitate an understanding of the molecular basis of the efficacy and side effects of MLN8237 as a clinical drug candidate. On the other hand, this work has also demonstrated that the method of DPAL could be a useful tool for target identification of bioactive small molecules.
Usefulness of the σ‐Aromaticity and σ‐Antiaromaticity Concepts for Clusters and Solid‐State Compounds
Authors: Popov Ivan A. , Starikova Alyona A. , Steglenko Dmitry V. , Boldyrev Alexander I. 
Published: June 2017

AbstractIn this Review we present examples of clusters, molecules, and solid‐state compounds, for which the use of σ‐aromaticity and σ‐antiaromaticity concepts is essential for understanding of chemical bonding. We show that the bonding patterns in these σ‐aromatic and σ‐antiaromatic compounds are similar to those of the corresponding π‐aromatic and π‐antiaromatic chemical systems, respectively. Undoubtedly, σ‐aromaticity helps us understand why the high symmetry isomers are the most stable among myriads of other potential structures. We also show that besides systems exhibiting either σ‐ or π‐aromatic features, there are species, which can possess multiple aromaticity/antiaromaticity, or conflicting aromaticity patterns. We believe that the σ‐aromaticity and σ‐antiaromaticity concepts will be helpful in rationalizing chemical bonding, structure, stability, and molecular properties of chemical species in both organic and inorganic chemistry. We hope that they will also be useful for other areas of science such as material science, catalysis, nanotechnology, and biochemistry.
α,β‐Unsaturated Amides as Dipolarophiles: Catalytic Asymmetric exo‐Selective 1,3‐Dipolar Cycloaddition with Nitrones
Authors: Zhang Ming , Kumagai Naoya , Shibasaki Masakatsu 
Published: June 2017

Abstract1,3‐Dipolar cycloaddition is a commonly exploited method to access 5‐membered chemical entities with a variety of peripheral functionalities and their stereochemical arrangements. Nitrones are isolable 1,3‐dipoles that exhibit sufficient reactivity toward electron‐deficient olefins in the presence of Lewis acids to deliver highly substituted isoxazolidines. Herein we document that α,β‐unsaturated amides, generally regarded as barely reactive in a 1,3‐dipolar reaction manifold, were effectively activated using the designed 7‐azaindoline auxiliary in an In(OTf)3/bishydroxamic acid catalytic system. The broad substrate scope and clean removal of the 7‐azaindoline auxiliary from the product highlight the synthetic utility of the present catalysis.
Two‐Step Spin‐Crossover with Three Inequivalent FeII Sites in a Two‐Dimensional Hofmann‐Type Coordination Polymer
Authors: Meng Yan , Sheng Qing‐Qing , Hoque Md. Najbul , Chen Yan‐Cong , Wu Si‐Guo , Tucek Jiri , Zboril Radek , Liu Tao , Ni Zhao‐Ping , Tong Ming‐Liang 
Published: June 2017

AbstractAn unprecedented two‐step spin‐crossover behavior with the sequence of γHS=1↔γHS=3/4↔γHS=1/4 was observed in two‐dimensional Hofmann type coordination polymer [Fe(isoq)2{Ag(CN)2}2] (isoq=isoquinoline), which resulted from three crystallographically inequivalent FeII sites with distinct transition temperatures.
Total Synthesis of 7‐epi‐Pukalide and 7‐Acetylsinumaximol B
Authors: McAulay Kirsten , Clark J. Stephen 
Published: June 2017

AbstractConvergent total syntheses of the furanocembranoids 7‐epi‐pukalide and 7‐acetylsinumaximol B have been achieved using a one‐pot Knoevenagel condensation and thioether‐mediated furan‐forming reaction. Furan formation proceeds via a sulfur ylide and results in rapid introduction of structural complexity during the coupling of two highly functionalised fragments. The targets have been prepared in 16 steps from (R)‐perillyl alcohol.
Generation of Maize (Zea mays) Doubled Haploids via Traditional Methods
Authors: Vanous Kimberly , Vanous Adam , Frei Ursula K. , Lübberstedt Thomas 
Published: June 2017

AbstractCommercial maize hybrid production has corroborated the usefulness of producing inbred lines; however, the delivery of new lines has always been a major time constraint in breeding programs. Traditional methods for developing inbred lines typically require 6 to 10 generations of self‐pollination to obtain sufficient homozygosity. To bypass the time and costs associated with the development of inbred lines, doubled haploid (DH) systems have been widely adopted in the commercial production of maize. Within just two generations, DH systems can create completely homozygous and homogeneous lines. A typical maize DH system, utilizing anthocyanin markers R1‐nj or Pl1 for haploid selection, is described in this protocol. © 2017 by John Wiley & Sons, Inc.
Defect Chemistry, Electrical Properties, and Evaluation of New Oxides Sr2CoNb1−xTixO6−δ (0≤x≤1) as Cathode Materials for Solid Oxide Fuel Cells
Authors: Azcondo María Teresa , Yuste Mercedes , Pérez‐Flores Juan Carlos , Muñoz‐Gil Daniel , García‐Martín Susana , Muñoz‐Noval Alvaro , Orench Inés Puente , García‐Alvarado Flaviano , Amador Ulises 
Published: June 2017

AbstractThe perovskite series Sr2CoNb1−xTixO6−δ (0≤x≤1) was investigated in the full compositional range to assess its potential as cathode material for solid oxide fuel cell (SOFC). The variation of transport properties and thus, the area specific resistances (ASR) are explained by a detailed investigation of the defect chemistry. Increasing the titanium content from x=0–1 produces both oxidation of Co3+ to Co4+ (from 0 up to 40 %) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit), although each charge compensation mechanism predominates in different compositional ranges. Neutron diffraction reveals that samples with high Ti‐contents lose a significant amount of oxygen upon heating above 600 K. Oxygen is partially recovered upon cooling as the oxygen release and uptake show noticeably different kinetics. The complex defect chemistry of these compounds, together with the compositional changes upon heating/cooling cycles and atmospheres, produce a complicated behavior of electrical conductivity. Cathodes containing Sr2CoTiO6−δ display low ASR values, 0,13 Ω cm2 at 973 K, comparable to those of the best compounds reported so far, being a very promising cathode material for SOFC.
Greening the Processes of Metal–Organic Framework Synthesis and their Use in Sustainable Catalysis
Authors: Chen Junying , Shen Kui , Li Yingwei 
Published: June 2017

AbstractGiven the shortage of sustainable resources and the increasingly serious environmental issues in recent decades, the demand for clean technologies and sustainable feedstocks is of great interest to researchers worldwide. With regard to the fields of energy saving and environmental remediation, the key point is the development of efficient catalysts, not only in terms of facile synthesis methods, but also the benign utilization of such catalysts. This work reviews the use of metal–organic frameworks (MOFs) and MOF‐based materials in these fields. The definition of MOFs and MOF‐based materials will be primarily introduced followed by a brief description of the characterization and stability of MOF‐related materials under the applied conditions. The greening of MOF synthesis processes will then be discussed and catalogued by benign solvents and conditions and green precursors of MOFs. Furthermore, their suitable application in sustainable catalysis will be summarized, focusing on several typical atom‐economic reactions, such as the direct introduction of H2 or O2 and C−C bond formation. Approaches towards reducing CO2 emission by MOF‐based catalysts will be described with special emphasis on CO2 fixation and CO2 reduction. In addition, driven by the explosive growth of energy consumption in the last century, much research has gone into biomass, which represents a renewable alternative to fossil fuels and a sustainable carbon feedstock for chemical production. The advanced progress of biomass‐related transformations is also illustrated herein. Fundamental insights into the nature of MOF‐based materials as constitutionally easily recoverable heterogeneous catalysts and as supports for various active sites is thoroughly discussed. Finally, challenges facing the development of this field and the outlook for future research are presented.
Cdk5 activity is required for Purkinje cell dendritic growth in cell‐autonomous and non‐cell‐autonomous manners
Authors: Xu Bozong , Kumazawa Ayumi , Kobayashi Shunsuke , Hisanaga Shin‐ichi , Inoue Takafumi , Ohshima Toshio 
Published: June 2017

ABSTRACTCyclin‐dependent kinase 5 (Cdk5) is recognized as a unique member among other Cdks due to its versatile roles in many biochemical processes in the nervous system. The proper development of neuronal dendrites is required for the formation of complex neural networks providing the physiological basis of various neuronal functions. We previously reported that sparse dendrites were observed on cultured Cdk5‐null Purkinje cells and Purkinje cells in Wnt1cre‐mediated Cdk5 conditional knockout (KO) mice. In the present study, we generated L7cre‐mediated p35; p39 double KO (L7cre‐p35f/f; p39–/–) mice whose Cdk5 activity was eliminated specifically in Purkinje cells of the developing cerebellum. Consequently, these mice exhibited defective Purkinje cell migration, motor coordination deficiency and a Purkinje dendritic abnormality similar to what we have observed before, suggesting that dendritic growth of Purkinje cells was cell‐autonomous in vivo. We found that mixed and overlay cultures of WT cerebellar cells rescued the dendritic deficits in Cdk5‐null Purkinje cells, however, indicating that Purkinje cell dendritic development was also supported by non‐cell‐autonomous factors. We then again rescued these abnormalities in vitro by applying exogenous brain‐derived neurotrophic factor (BDNF). Based on the results from culture experiments, we attempted to rescue the developmental defects of Purkinje cells in L7cre‐p35f/f; p39–/– mice by using a TrkB agonist. We observed partial rescue of morphological defects of dendritic structures of Purkinje cells. These results suggest that Cdk5 activity is required for Purkinje cell dendritic growth in cell‐autonomous and non‐cell‐autonomous manners. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1175–1187, 2017
Fragmentation increases wind disturbance impacts on forest structure and carbon stocks in a western Amazonian landscape
Authors: Schwartz Naomi B. , Uriarte María , DeFries Ruth , Bedka Kristopher M. , Fernandes Katia , Gutiérrez‐Vélez Victor , Pinedo‐Vasquez Miguel A. 
Published: June 2017

AbstractTropical second‐growth forests could help mitigate climate change, but the degree to which their carbon potential is achieved will depend on exposure to disturbance. Wind disturbance is common in tropical forests, shaping structure, composition, and function, and influencing successional trajectories. However, little is known about the impacts of extreme winds on second‐growth forests in fragmented landscapes, though these ecosystems are often located in mosaics of forest, pasture, cropland, and other land cover types. Indirect evidence suggests that fragmentation increases risk of wind damage in tropical forests, but no studies have found such impacts following severe storms. In this study, we ask whether fragmentation and forest type (old vs. second growth) were associated with variation in wind damage after a severe convective storm in a fragmented production landscape in western Amazonia. We applied linear spectral unmixing to Landsat 8 imagery from before and after the storm, and combined it with field observations of damage to map wind effects on forest structure and biomass. We also used Landsat 8 imagery to map land cover with the goals of identifying old‐ and second‐growth forest and characterizing fragmentation. We used these data to assess variation in wind disturbance across 95,596 ha of forest, distributed over 6,110 patches. We find that fragmentation is significantly associated with wind damage, with damage severity higher at forest edges and in edgier, more isolated patches. Damage was also more severe in old‐growth than in second‐growth forests, but this effect was weaker than that of fragmentation. These results illustrate the importance of considering landscape context in planning tropical forest restoration and natural regeneration projects. Assessments of long‐term carbon sequestration potential need to consider spatial variation in disturbance exposure. Where risk of extreme winds is high, minimizing fragmentation and isolation could increase carbon sequestration potential.
Vitamin D levels strongly influence bone mineral density and bone turnover markers during weight gain in female patients with anorexia nervosa
Authors: Giollo Alessandro , Idolazzi Luca , Caimmi Cristian , Fassio Angelo , Bertoldo Francesco , Dalle Grave Riccardo , El Ghoch Marwan , Calugi Simona , Bazzani Paola Vittoria , Viapiana Ombretta , Rossini Maurizio , Gatti Davide 
Published: June 2017

AbstractObjectiveThe aim of the study was to investigate a potential role for vitamin D status on bone mineral density (BMD) during weight gain in patients with anorexia nervosa (AN).MethodSpine and hip BMD assessed by dual‐energy X‐ray absorptiometry (DXA), serum vitamin D (25‐OH‐D), N‐propeptide of type I collagen (P1NP), C‐terminal telopeptide of type I collagen (CTX), and intact parathyroid hormone (PTH) were measured before and after a 20‐week intensive weight‐restoration program in ninety‐one female patients with AN and secondary amenorrhoea.ResultsNinety‐one consecutive female patients (age 13–45 years; weight 39.4 ± 5.6 kg, body mass index [BMI] 15.1 ± 1.6 kg m−2) were included in the study. Although weight and BMI significantly increased in all patients during treatment, mean BMD only significantly increased at the spine (1.0% ± 3.6%, p = .009). The increase in spine BMD was significantly higher only above post‐treatment 25‐OH‐D levels of 30 ng mL−1 (2.5% vs. 0.5%, respectively, for 25‐OH‐D ≥ and < 30 ng mL−1, p = .026). There was a significant decrease in bone resorption (CTX; p = .043) and increased bone formation (P1NP; p < .001) after weight restoration. Nevertheless, a significant increase in PTH was also found, which was inversely correlated with decreased post‐treatment 25‐OH‐D levels (R2 = .153, p < .001).DiscussionHypovitaminosis D may counteract the efficacy of refeeding in AN through increased bone resorption mediated by secondary hyperparathyroidism, which strongly supports the use of vitamin D supplements for bone health in AN.
Macronutrient intake associated with weight gain in adolescent girls with anorexia nervosa
Authors: Baskaran Charumathi , Carson Traci L. , Campoverde Reyes Karen J. , Becker Kendra R. , Slattery Meghan J. , Tulsiani Shreya , Eddy Kamryn T. , Anderson Ellen J. , Hubbard Jane L. , Misra Madhusmita , Klibanski Anne 
Published: June 2017

AbstractObjectiveAdolescents and women with anorexia nervosa (AN) are known to severely restrict total calorie and fat intake. However, data are limited regarding specific macronutrient intake associated with weight gain in AN.ObjectiveTo prospectively investigate dietary macronutrient composition associated with weight gain in adolescent girls with AN.MethodA prospective naturalistic study of 90 girls 12–18 years old; 45 with AN and 45 healthy normal‐weight‐controls over a 6–12‐month period. Participants completed four‐day food diaries and underwent body composition assessment using dual energy X‐ray absorptiometry. Weight gain was defined as a ≥10% increase in body mass index (BMI) from baseline.ResultsBaseline clinical characteristics did not differ between girls with AN who did not gain weight (AN‐0) versus those who did (AN‐1) over the following 6–12 month period except for percentage of calories from proteins (p = 0.046). At 6–12 month follow‐up, AN‐1 consumed a lower percentage of total calories from protein (p = .001), and a higher percentage of total calories from fat (p = .02) compared to AN‐0. AN‐1 had a significant increase in the percentage of total calories obtained from and poly‐unsaturated‐fatty acids (PUFA) (p = 0.006) compared to AN‐0, between baseline and follow‐up. Within the AN group, BMI at follow‐up was associated positively with percentage of total calories obtained from fat, MUFA, and PUFA (p < .05) at 6/12 months, and inversely with the percentage of total calories obtained from carbohydrates and proteins (p = .03).DiscussionConsuming a greater proportion of total calories from fat is associated with weight gain in adolescent girls with AN.
Litter is more effective than forest canopy reducing soil evaporation in Dry Chaco rangelands
Authors: Magliano Patricio N. , Giménez Raúl , Houspanossian Javier , Páez Ricardo A. , Nosetto Marcelo D. , Fernández Roberto J. , Jobbágy Esteban G. 
Published: June 2017

AbstractSoil evaporation is a dominant water flux of flat dry ecosystems, reducing available water for plant transpiration. Vegetation plays a key role at controlling evaporation, especially by altering soil surface micro‐meteorological conditions. Here, we explored the vegetation cover effect on soil evaporation, differentiating the effects of canopy cover (shadow) and of surface cover (litter) in forests and pastures of Dry Chaco rangelands (San Luis, Argentina). We measured daily soil evaporation using irrigated micro‐lysimeters installed at regularly spaced (2 m) patches along transects in native dry forests (n = 54 patches) and pastures (n = 27 patches). In each forest patch, we established a pair of micro‐lysimeters, one with litter (3 cm depth, representing high litter cover conditions of the site) and one with bare soil, but in pastures, only one micro‐lysimeter with bare soil was installed at each patch (representing the typical no litter cover conditions of pastures of the study site). We found that, when soil water was not limiting, litter cover had the strongest effect in reducing evaporation rates, with a 4‐ and 6.4‐fold reduction respect to bare soil micro‐lysimeters in the forest and pasture, respectively. Evaporation decreased sharply with declining incident radiation fraction in bare soil micro‐lysimeters from 5.6 mm/day (full radiation) to 3.5 mm/day (full canopy shadow; R2 = 0.50). Litter‐covered micro‐lysimeters showed lower and more stable evaporation rates, decreasing only from 1.35 to 1.03 mm/day under the same radiation conditions (R2 = 0.10). In accordance with J.T. Ritchie evaporation model, we identified a threshold of ~10.5 mm of cumulative evaporation at which evaporation switched from energy to water limitation in all situations, as revealed by declining evaporation rates and raising surface temperatures. Under typical wet–summer conditions, the pasture, the forest with bare soil, and the forest with litter would need on average a drying cycle of 1.5, 2.5, and 9.5 days, respectively, to reach that threshold. Simulations showed that, considering the distribution of rainfall events at our study site, litter would maintain evaporation in the energy‐limited mode most of the time (68.8% of summer days), potentially favouring transpiration. The ecohydrological key role of soil litter controlling evaporation highlights the importance of an accurate assessment of management practices controlling the evaporation/transpiration partition in dry ecosystems.