bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pre‐Polymerization Enables Controllable Synthesis of Nanosheet‐Based Porphyrin Polymers towards High‐Performance Li‐Ion Batteries
Authors: Han Zhuolei , Ai Yan , Jiang Xiaolin , You Yuxiu , Wei Facai , Luo Hao , Cui Jing , Bao Qinye , Fu Jianwei , He Qingguo , Liu Shaohua , Cheng Jiangong 
Published: May 2020

AbstractThe precise regulation of nucleation growth and assembly of polymers is still an intriguing goal but an enormous challenge. In this study, we proposed a pre‐polymerization strategy to regulate the assembly and growth of polymers by facilely controlling the concentration of polymerization initiator, and thus obtained two kinds of different nanosheet‐based porphyrin polymer materials using tetrakis‐5,10,15,20‐(4‐aminophenyl) porphyrin (TAPP) as the precursor. Notably, due to the π–π stacking and doping of TAPP during the preparation process, the obtained PTAPP‐nanocube material exhibits a high intrinsic bulk conductivity reaching 1.49×10−4 S m−1. Profiting from the large π‐conjugated structure of porphyrin units, closely stacked layer structure and excellent conductivity, the resultant porphyrin polymers, as electrode materials for lithium ion batteries, deliver high specific capacity (≈650 mAh g−1 at the current density of 100 mA g−1), excellent rate performance and long‐cycle stability, which are among the best reports of porphyrin polymer‐based electrode materials for lithium‐ion batteries, to the best of our knowledge. Therefore, such a pre‐polymerization approach would provide a new insight for the controllable synthesis of polymers towards custom‐made architecture and function.
Carbon Monoxide Coupling Reactions: A New Concept for the Formation of Hexahydroxybenzene
Authors: Rosenthal Uwe 
Published: May 2020

AbstractFor linear and cyclic coupling reactions of CO, among other products, the formation of the hexapotassium salt of hexahydroxybenzene is of particular interesting. The interaction of metallic potassium and CO offers, via the assumed K[OC≡CO]K as the result of several carbon monoxide coupling reactions, the formation of C6(OK)6 among other products. To date, only speculations exist about the reaction pathway for these products, which were first described by Liebig in 1834. A novel concept is suggested here, which consists of the single steps (i) reductive coupling of CO, (ii) formation of dihetero‐metallacyclopentynes (cis‐2,5‐diheterobutatriene as formal ethylenedione O=C=C=O complexes), (iii) formation of its dinuclear 1‐metalla‐2,5‐dioxo‐cyclopentyne complexes by external coordination of the triple bond, (iv) insertion of CO into the M−C bond of the formed metallacyclopropene, and (v) the reductive elimination of C6(OK)6. The novel aspect of this concept is the formation of dihetero‐metallacyclopentynes (in analogy to the well characterized all‐C‐metallacyclopentynes), which have not been considered in the mechanism of reductive CO coupling reactions. It is expected that the presence of transition‐metal impurities would promote the reaction.
An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers
Authors: Rauch Florian , Endres Peter , Friedrich Alexandra , Sieh Daniel , Hähnel Martin , Krummenacher Ivo , Braunschweig Holger , Finze Maik , Ji Lei , Marder Todd B. 
Published: May 2020

AbstractUsing a new divergent approach, conjugated triarylborane dendrimers were synthesized up to the 2nd generation. The synthetic strategy consists of three steps: 1) functionalization, via iridium catalyzed C−H borylation; 2) activation, via fluorination of the generated boronate ester with K[HF2] or [N(nBu4)][HF2]; and 3) expansion, via reaction of the trifluoroborate salts with aryl Grignard reagents. The concept was also shown to be viable for a convergent approach. All but one of the conjugated borane dendrimers exhibit multiple, distinct and reversible reduction potentials, making them potentially interesting materials for applications in molecular accumulators. Based on their photophysical properties, the 1st generation dendrimers exhibit good conjugation over the whole system. However, the conjugation does not increase further upon expansion to the 2nd generation, but the molar extinction coefficients increase linearly with the number of triarylborane subunits, suggesting a potential application as photonic antennas.
Dynamic PdII/CuIMultimetallic Assemblies as Molecular Models to Study Metal–Metal Cooperation in Sonogashira Coupling
Authors: Rivada‐Wheelaghan Orestes , Comas‐Vives Aleix , Fayzullin Robert R. , Lledós Agustí , Khusnutdinova Julia R. 
Published: May 2020

AbstractCooperation between two different metals plays a crucial role in many synergistic catalytic reactions, such as the Sonogashira C−C cross‐coupling reaction, where an interaction between the Pd and Cu centers is proposed in the transmetalation step. Although several heterobimetallic Pd/Cu complexes were proposed as structural models of the active species in Sonogashira coupling, the detailed understanding of the metal–metal cooperation in transmetalation is still lacking in current systems. In this work, we report a stepwise and systematic approach to building heteromultimetallic Pd/Cu assemblies as a tool to study metal–metal cooperativity. We obtained fully characterized Pd/Cu multimetallic assemblies that show reactivity in alkyne activation, formation of catalytically relevant aryl/acetylide species, and C−C elimination, serving as functional models for Sonogashira reaction intermediates. The combined experimental and DFT studies highlight the importance of ligand‐controlled coordination geometry, metal–metal distances and dynamics of the multimetallic assembly for transmetalation step.
Synthesis of a Molecule with Five Different Adjacent Pnictogens
Authors: Ritter Christian , Weigend Florian , von Hänisch Carsten 
Published: May 2020

AbstractThe first molecular compound with all five pnictogens was obtained by a multi‐step reaction. Lithiation of the (bisamido)diazadiarsetidine (tBuNAs)2(tBuNH)2 in aliphatic solvents leads to the dimeric metallated species [(tBuNAs)2(tBuNLi)2]2 (12). Upon reactions with AsCl3, SbCl3 and BiCl3 the polycyclic compounds [(tBuNAs)2(tBuN)2]PnCl (Pn=As (2), Sb (3), Bi (4)) can be obtained. Conversion of 2–4 with [tBu2SbP(tBu)Li(OEt2)]2 leads to the remarkable interpnictogens [(tBuNAs)2(tBuN)2]PnP(tBu)SbtBu2 (Pn=As (5), Sb (6), Bi (7)), whereby 7 is the first example of a molecule containing all five Group 15 elements. The compound with adjacent AsNBiPSb‐chains is surprisingly stable and does not show high sensibility against light as the labile Bi−P bond might suggest.
Productive Syntheses of Privileged Scaffolds Inspired by the Recognition of a Diels–Alder Pattern Common to Three Classes of Natural Products
Authors: Badarau Eduard , Reddy K. Harsha Vardhan , Loudet Aurore , Simon Charles , Trembleau Laurent , Claerhout Stijn , Pair Etienne , Massip Stéphane , Breton Philippe , Lesur Brigitte , Goldstein Solo , Fourquez Jean‐Marie , Henlin Jean Michel , Ghosez Léon 
Published: May 2020

AbstractIdentification of a common Diels–Alder pattern in three classes of bioactive natural products led us to study the synthesis and cycloaddition of a new class of cyclic dienes readily available from β,γ‐unsaturated lactams. A practical and readily scalable route to the parent p‐methoxybenzyl‐protected 6‐ and 7‐membered β,γ‐unsaturated lactams was developed. These were readily transformed into the corresponding O‐silylated dienes, which were reacted with dimethyl and diethyl fumarate to yield stereoselectively highly functionalized bicyclic adducts. These exhibited unexpected and versatile transformations upon acid hydrolysis depending on the nature of the dienophile substituents and the acid catalyst. All reactions have been performed on multigram quantities. These transformations provide a convenient, economical, and easily scalable pathway for the rapid construction of functionally and stereochemically dense privileged scaffolds for the construction of libraries of natural products‐inspired molecules of pharmacological relevance.
RhIII‐Catalyzed C−H Activation of Aryl Hydroxamates for the Synthesis of Isoindolinones
Authors: Shaaban Saad , Davies Caitlin , Merten Christian , Flegel Jana , Otte Felix , Strohmann Carsten , Waldmann Herbert 
Published: May 2020

AbstractRhIII‐catalyzed C−H functionalization reaction yielding isoindolinones from aryl hydroxamates and ortho‐substituted styrenes is reported. The reaction proceeds smoothly under mild conditions at room temperature, and tolerates a range of functional groups. Experimental and computational investigations support that the high regioselectivity observed for these substrates results from the presence of an ortho‐substituent embedded in the styrene. The resulting isoindolinones are valuable building blocks for the synthesis of bioactive compounds. They provide easy access to the natural‐product‐like compounds, isoindolobenzazepines, in a one‐pot two‐step reaction. Selected isoindolinones inhibited Hedgehog (Hh)‐dependent differentiation of multipotent murine mesenchymal progenitor stem cells into osteoblasts.
Chemical‐Fuel‐Driven Assembly in Macromolecular Science: Recent Advances and Challenges
Authors: Leng ZeJian , Peng Feng , Hao Xiang 
Published: May 2020

AbstractIn the past decade, chemical‐fuel‐driven processes have been integrated with synthetic self‐assembled systems, in which both the formation and properties can be carefully controlled. This strategy can drive systems far away from equilibrium, tailor the lifetime window of transient self‐assembled systems, thus holding promise for future smart, adaptive, self‐regulated, and life‐like systems. By judging whether the building blocks or transient self‐assembled systems participate in the fuel‐to‐waste conversion, the reported systems can be divided into two classes: dissipative self‐assembly and self‐assembly under dissipative conditions. Among these systems, the utilization of macromolecular building blocks to design non‐equilibrium self‐assemblied systems is becoming common. Macromolecular systems capable of dissipating energy with a programmed time domain have found widespread application, and have therefore been an active field of scientific inquiry. This Minireview aims to highlight the recent progress and opportunities of chemical‐fuel‐driven assembly in macromolecules. We envision that chemical‐fuel‐driven approach will play an increasingly important role in polymer science in the near future.
Agronomic performance and cooking quality characteristics for slow‐darkening pinto beans
Authors: Miklas Phillip N. , Osorno Juan M. , Chaves Bernardo , Cichy Karen A. 
Published: May 2020

AbstractSlow‐darkening (SD) pinto beans (Phaseolus vulgaris L.) possess a desirable new trait, conditioned by the recessive sd gene, that slows seed coat darkening under delayed harvest and under storage. The effect sd may have on performance needs investigation. We examined agronomic performance and cooking quality of SD pinto beans. There were 30 (15 SD and 15 regular darkening [RD]) recombinant inbred lines (RILs) from each of two biparental inbred populations. The 60 RILs were tested across three locations in North Dakota and Washington. In addition, advanced SD and RD pinto breeding lines were tested in trials from 2010 to 2012 and in 2018. Across 2010–2012 trials, the “early generation bred” SD pintos, as a group, had significantly lower emergence, increased lodging, less seed yield, and smaller seed size than the RD group. Conversely, in the 2018 trial, “recently bred” SD pinto breeding lines had competitive agronomic performance to RD lines for seed yield, reduced lodging, and increased emergence. Further research on cooking time is warranted given that SD RILs cooked 20% faster than the RD RILs in one population. Overall, SD pintos exhibited slightly better canning quality than RD pintos. Whether raw or cooked, SD pintos were much lighter in color than RD pintos, emphasizing the need to keep them separated as distinct market classes. Breeders should continue to focus on improving agronomic performance for emergence, lodging, seed yield, seed size, and canning quality of SD pinto beans.
Shock waves in a rotating non‐Maxwellian viscous dusty plasma
Authors: Ehsan Zahida , Abbasi Muhammad M. , Ghosh Samiran , Khan Majid , Ali Muddasir 
Published: May 2020

AbstractA theoretical model is presented to study the characteristics of dust acoustic shock in a viscous, magnetized, rotating dusty plasma at both fast and slow time scales. By employing the reductive perturbation technique, the non‐linear Zakharov–Kuznetsov–Burger (ZKB) equation is derived for both cases when the dust is inactive and dynamic (fast and slow time scales). Both electrons and ions are considered to follow the kappa/Cairns distribution. It is observed that in both cases, i.e. when dust is in the background and active, viscosity plays a key role in dissipation for the propagation of acoustic shock. Magnetic field and rotation are responsible for the dispersive term. Superthermality is found to affect significantly the formation of the shock wave along with viscous nature of plasma, whereas the dust charge affects the non‐linear coefficient of the ZKB equation. The present investigation may be beneficial to the understanding of the rotating plasma, in particular the experiments being carried
out.
Effects of diet, habitat, and phylogeny on the fecal microbiome of wild African savanna (Loxodonta africana) and forest elephants (L. cyclotis)
Authors: Budd Kris , Gunn Joe C. , Finch Tabitha , Klymus Katy , Sitati Noah , Eggert Lori S. 
Published: May 2020

AbstractThe gut microbiome, or the community of microorganisms inhabiting the digestive tract, is often unique to its symbiont and, in many animal taxa, is highly influenced by host phylogeny and diet. In this study, we characterized the gut microbiome of the African savanna elephant (Loxodonta africana) and the African forest elephant (Loxodonta cyclotis), sister taxa separated by 2.6–5.6 million years of independent evolution. We examined the effect of host phylogeny on microbiome composition. Additionally, we examined the influence of habitat types (forest versus savanna) and diet types (crop‐raiding versus noncrop‐raiding) on the microbiome within L. africana. We found 58 bacterial orders, representing 16 phyla, across all African elephant samples. The most common phyla were Firmicutes, Proteobacteria, and Bacteroidetes. The microbiome of L. africana was dominated by Firmicutes, similar to other hindgut fermenters, while the microbiome of L. cyclotis was dominated by Proteobacteria, similar to more frugivorous species. Alpha diversity did not differ across species, habitat type, or diet, but beta diversity indicated that microbial communities differed significantly among species, diet types, and habitat types. Based on predicted KEGG metabolic pathways, we also found significant differences between species, but not habitat or diet, in amino acid metabolism, energy metabolism, and metabolism of terpenoids and polyketides. Understanding the digestive capabilities of these elephant species could aid in their captive management and ultimately their conservation.
Trait‐based climate vulnerability of native rodents in southwestern Mexico
Authors: Ramírez‐Bautista Arturo , Thorne James H. , Schwartz Mark W. , Williams John N. 
Published: May 2020

AbstractAimIncorporate species’ trait information together with climate projections for associated habitat to assess the potential vulnerability of rodent taxa to climate change.LocationOaxaca State, Mexico.MethodsWe used a trait‐based approach together with climate exposure models to evaluate the vulnerability of rodent species to projected climate conditions in the study region. Vulnerability was estimated based on three factors: (a) Level of climatic exposure that species are projected to experience across their current statewide range; (b) inherent species‐specific sensitivity to stochastic events; and (c) species’ capacity to cope with climate change effects. We defined species as inherently sensitive if they had any of the following: restricted geographic distribution in Mexico; narrow altitudinal range; low dispersal ability; or long generation length.ResultsVulnerability varied depending on the climate change scenario applied. Under the MPI general circulation model and current emissions trends, by 2099, all species evaluated were projected to have some level of threat (vulnerable for at least one factor), with 4 out of 55 species vulnerable for all three factors, 29 for two factors, and 22 for one factor. Six out of ten rodent species endemic to Oaxaca were vulnerable for two or more factors. We found that species with narrow and restricted‐range distributions combined with low adaptive capacity were projected to be particularly vulnerable.Main conclusionsBy including species‐specific trait information in climate exposure assessments, researchers can contextualize and enhance their understanding about how climate change is likely to affect individual taxa in an area of interest. As such, studies like this one provide more relevant threat assessment information than exposure analyses alone and serve as a starting point for considering how climatic changes interact with an array of other variables to affect native species across their range.
Environmental controls on Landsat‐derived phenoregions across an East African megatransect
Authors: Desanker Gloria , Dahlin Kyla M. , Finley Andrew O. 
Published: May 2020

AbstractSemiarid and savanna‐type (SAST) ecosystems in East Africa have unique plant species compositions and characteristics that make quantifying this biome's seasonality and interannual variability difficult. Phenoregion classification offers a way to use seasonality of vegetation growth to help understand the phenological spatial patterns of complex landscapes. Here, we used Normalized Difference Vegetation Index (NDVI) time series from Landsat 8 to map phenoregions in scenes centered around national parks from Mt. Kenya National Park (Kenya) to Limpopo National Park (Mozambique). We then assessed whether landscape‐scale controls on phenology are consistent across the region or whether they vary across this latitudinal gradient. We compared our phenoregion maps to MODIS Land Cover and geology, and we used multinomial logistic regression to determine the role that elevation, slope, aspect, and geology play in driving phenological differences. The sites' phenoregions showed no unique land cover composition, suggesting that MODIS land cover does not capture the subtle variations identified in phenoregion analysis. Multinomial logistic regression showed that geographic trend (x‐ and y‐directions) was a strong predictor in four of the five landscapes and that, depending on the scene, geology, elevation, or aspect was a strong secondary predictor. Using seasonality of the NDVI time series to generate phenoregions provides different and, in some cases, more ecologically relevant information, compared to vegetation maps that use only land cover from a single season or time period to generate ecoregions. With a significant population of humans and animals that live in and depend on SAST ecosystems, it is important to better understand vegetation processes and factors that affect them as climate change becomes an increasingly pertinent issue in dry systems.
Ga‐based microencapsulated phase change material for low‐temperature thermal management applications
Authors: Kashiyama Kohei , Kawaguchi Takahiro , Dong Kaixin , Sakai Hiroki , Sheng Nan , Kurniawan Ade , Nomura Takahiro 
Published: May 2020

AbstractGallium is expected to use as a high‐performance phase change material (PCM) for a low‐temperature thermal management. However, high corrosivity of liquid gallium is a serious technical barrier to handle gallium as a PCM. To this end, we report on the development of a Ga‐based microencapsulated PCM (MEPCM) by using a three‐step process. First, Ga is particularized by high‐speed mixing. Second, a GaOOH shell is precipitated on the surface of the Ga particles by chemical treatment. Finally, the GaOOH shell is subjected to an oxidation treatment, after which the shell transforms into a Ga2O3 shell. As the results, MEPCM obtained at the oxidation temperature of 600°C was the only one completely covered with a shell without agglomeration. The MEPCM was composed of a β‐Ga2O3 shell and Ga core with internal voids, whose presence can relieve the pressure on the shell owing to the volume expansion of the core during solidification. The latent heat of the MEPCM was nearly 56% that of the Ga particles. This study demonstrates the first successful microencapsulation of Ga and exhibits the potential of Ga as a new thermal management material.
Targeted next generation sequencing of MLH1‐deficient, MLH1 promoter hypermethylated, and BRAF/RAS‐wild‐type colorectal adenocarcinomas is effective in detecting tumors with actionable oncogenic gene fusions
Authors: Vaňková Bohuslava , Vaněček Tomáš , Ptáková Nikola , Hájková Veronika , Dušek Martin , Michal Michael , Švajdler Peter , Daum Ondřej , Daumová Magdaléna , Michal Michal , Mezencev Roman , Švajdler Marián 
Published: May 2020

AbstractOncogenic gene fusions represent attractive targets for therapy of cancer. However, the frequency of actionable genomic rearrangements in colorectal cancer (CRC) is very low, and universal screening for these alterations seems to be impractical and costly. To address this problem, several large scale studies retrospectivelly showed that CRC with gene fusions are highly enriched in groups of tumors defined by MLH1 DNA mismatch repair protein deficiency (MLH1d), and hypermethylation of MLH1 promoter (MLH1ph), and/or the presence of microsatellite instability, and BRAF/KRAS wild‐type status (BRAFwt/KRASwt). In this study, we used targeted next generation sequencing (NGS) to explore the occurence of potentially therapeutically targetable gene fusions in an unselected series of BRAFwt/KRASwt CRC cases that displayed MLH1d/MLH1ph. From the initially identified group of 173 MLH1d CRC cases, 141 cases (81.5%) displayed MLH1ph. BRAFwt/RASwt genotype was confirmed in 23 of 141 (~16%) of MLH1d/MLH1ph cases. Targeted NGS of these 23 cases identified oncogenic gene fusions in nine patients (39.1%; CI95: 20.5%‐61.2%). Detected fusions involved NTRK (four cases), ALK (two cases), and BRAF genes (three cases). As a secondary outcome of NGS testing, we identified PIK3K‐AKT‐mTOR pathway alterations in two CRC cases, which displayed PIK3CA mutation. Altogether, 11 of 23 (~48%) MLH1d/MLH1ph/BRAFwt/RASwt tumors showed genetic alterations that could induce resistance to anti‐EGFR therapy. Our study confirms that targeted NGS of MLH1d/MLH1ph and BRAFwt/RASwt CRCs could be a cost‐effective strategy in detecting patients with potentially druggable oncogenic kinase fusions.