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<p>Supplementary Table 5. The Adjusted Associations of Body Composition Measurements (Per SD Increase) with Reduced RDI Counting from the Initiation of First Chemotherapy</p>
Self-phase modulation in a ${\mathrm{CO}}_{2}$-laser breakdown plasma is observed to down-shift the wavelength from 10.6 to about 10.0 \ensuremath{\mu}m. This results from the sudden drop in refractive index, from 1 to 0, which accompanies the ionization of the gas. The pressure dependence of this effect in nitrogen is opposite to that in helium.
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTRegiodefined Poly(N-arylaniline)s and Donor−Acceptor Copolymers via Palladium-Mediated Amination ChemistryFelix E. Goodson and John F. HartwigView Author Information Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107 Cite this: Macromolecules 1998, 31, 5, 1700–1703Publication Date (Web):February 19, 1998Publication History Received7 January 1998Published online19 February 1998Published inissue 1 March 1998https://pubs.acs.org/doi/10.1021/ma980027rhttps://doi.org/10.1021/ma980027rrapid-communicationACS PublicationsCopyright © 1998 American Chemical SocietyRequest reuse permissionsArticle Views673Altmetric-Citations61LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Group 15 compounds,Materials,Monomers,Polymerization,Polymers Get e-Alerts
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Herein is reported the direct asymmetric addition of phenol nucleophiles to benzopyrylium salts as a means to produce enantioenriched flavonoid-like compounds. This enantioselective C-C bond construction was achieved through a chiral anion phase-transfer strategy that mimics the proposed biosynthesis of this structurally diverse set of natural products. The utility of this methodology was demonstrated in enantioselective synthesis of a 2,8-dioxabicyclo[3.3.1]nonane and a 2,4-diarylbenzopyran.
A series of Pt complexes activated by Ag(I)\nsalts have been shown to catalyze Markovnikov hydroarylations of unactivated olefins under mild conditions.
The layer-by-layer additive manufacturing approach results in the 3D printed composite lattice structure fails to exploit fiber reinforcement, thereby resulting in inferior mechanical qualities. To address this challenge, this study proposes a novel approach leveraging composite fused filament fabrication (FFF) printing to design modular assembled composite lattice structures. Initially, three high-performance lattice structures were transformed into discrete 2D components and assembled into 3D lattice structures. Subsequently, the mechanical properties of these structures were comprehensively assessed using theoretical, experimental, and finite element analysis methods. Finally, the comparison between the assembled structures and integrated printed lattice structures in terms of surface quality, mechanical properties, and manufacturability revealed significant advantages. The theoretical and finite element analyses accurately predicted the mechanical properties of the lattice structures. The lattice structures that were assembled in a modular way displayed an impressive 74% improvement in surface finish. Additionally, they showed peak strength increases of 140%, 27%, and 26%, respectively, for the mentioned types of topology. The energy absorption also increased significantly by 510.83%, 44.18%, and 30.24%. Furthermore, these assembled structures required less printing support materials, enhancing their manufacturability and cost-effectiveness. This new method of designing modular space structures goes beyond the limitations imposed by equipment by using high-performance topology. It allows for the construction of large-scale, lightweight space structures that offer excellent performance. This study explores innovative opportunities in the field of space manufacturing, offering potential implications for the development of lunar habitats, space telescopes, and space power stations.
Enantioselective allylic substitution reactions comprise some of the most versatile methods for preparing enantiomerically enriched materials. These reactions form products that contain multiple functionalities by creating carbon-nitrogen, carbon-oxygen, carbon-carbon, and carbon-sulfur bonds. For many years, the development of catalysts for allylic substitution focused on palladium complexes. However, studies of complexes of other metals have revealed selectivities that often complement those of palladium systems. Most striking is the observation that reactions with unsymmetrical allylic electrophiles that typically occur with palladium catalysts at the less hindered site of an allylic electrophile occur at the more hindered site with catalysts based on other metals. In this Account, we describe the combination of an iridium precursor and a phosphoramidite ligand that catalyzes enantioselective allylic substitution reactions with a particularly broad scope of nucleophiles. The active form of this iridium catalyst is not generated by the simple binding of the phosphoramidite ligand to the metal precursor. Instead, the initial phosphoramidite and iridium precursor react in the presence of base to form a metallacyclic species that is the active catalyst. This species is generated either in situ or separately in isolated form by reactions with added base. The identification of the structure of the active catalyst led to the development of simplified catalysts as well as the most active form of the catalyst now available, which is stabilized by a loosely bound ethylene. Most recently, this structure was used to prepare intermediates containing allyl ligands, the structures of which provide a model for the enantioselectivities discussed here. Initial studies from our laboratory on the scope of iridium-catalyzed allylic substitution showed that reactions of primary and secondary amines, including alkylamines, benzylamines, and allylamines, and reactions of phenoxides and alkoxides occurred in high yields, with high branched-to-linear ratios and high enantioselectivities. Parallel mechanistic studies had revealed the metallacyclic structure of the active catalyst, and subsequent experiments with the purposefully formed metallacycle increased the reaction scope dramatically. Aromatic amines, azoles, ammonia, and amides and carbamates as ammonia equivalents all reacted with high selectivities and yields. Moreover, weakly basic enolates (such as silyl enol ethers) and enolate equivalents (such as enamines) also reacted, and other research groups have used this catalyst to conduct reactions of stabilized carbon nucleophiles in the absence of additional base. One hallmark of the reactions catalyzed by this iridium system is the invariably high enantioselectivity, which reflects a high stereoselectivity for formation of the allyl intermediate. Enantioselectivity typically exceeds 95%, regioselectivity for formation of branched over linear products is usually near 20:1, and yields generally exceed 75% and are often greater than 90%. Thus, the development of iridium catalysts for enantioselective allylic substitution shows how studies of reaction mechanism can lead to a particularly active and a remarkably general system for an enantioselective process. In this case, a readily accessible catalyst effects allylic substitution, with high enantioselectivity and regioselectivity complementary to that of the venerable palladium systems.
This study proposes a new metric called canopy geometric volume G, which is derived from small-footprint lidar data, for estimating individual-tree basal area and stem volume. Based on the plant allometry relationship, we found that basal area B is exponentially related to G (B �� 1G 3⁄4 , where � 1 is a constant) and stem volume V is proportional to G (V � � 2G, where � 2 is a constant). The models based on these relationships were compared with a number of models based on tree height and/or crown diameter. The models were tested over individual trees in a deciduous oak woodland in California in the case that individual tree crowns are either correctly or incorrectly segmented. When trees are incorrectly segmented, the theoretical model B � � 1G 3⁄4 has the best performance (adjusted R 2 , � 0.78) and the model V � � 2G has the second to the best performance ( � 0.78). When trees are correctly segmented, the theoretical models are among the top three models for estimating basal area ( � 0.77) and stem volume ( � 0.79). Overall, these theoretical models are the best when considering a number of factors such as the performance, the model parsimony, and the sensitivity to errors in tree crown segmentation. Further research is needed to test these models over sites with multiple species.
