Alkylnitriles are one of the most ubiquitous nitrogen‐containing chemicals and are widely employed in reactions which result in nitrile‐group conversion into other functionalities. Nevertheless, ...their use as carbon pronucleophiles in carbon–carbon bond‐forming reactions has been hampered by difficulties associated mainly with the catalytic generation of active species, that is, α‐cyano carbanions or metalated nitriles. Recent investigations have addressed this challenge and have resulted in different modes of alkylnitrile activation. This review illustrates these findings, which have set the foundation for the development of practical and conceptually new catalytic, direct cyanoalkylation methodologies.
On the playlist: This review provides an overview on the catalytic activation modes employed to overcome the attenuated reactivity of alkylnitriles as carbon pronucleophiles in catalytic carbon–carbon bond‐forming reactions. The lack of catalytic asymmetric procedures clearly poses a challenge and offers a great opportunity for future improvements in this emerging area of research.
Motherhood and childhood are social and cultural constructions that have their origins in prehistoric times and are visible through Greek and Roman discourses in Antiquity. This volume explores ...various images of maternity and infancy, and the identification of women and womanhood in prehistoric and classic societies. Aspects such as the crucial role of maintenance activities and care, the processes of socialization and learning, the impact of infant death, the figure of the mother queen, the religious discourses about motherhood, the rules on parental rights, the transgressions of traditional motherhood and the emotional aspects of the mother-child relation are analysed. The book covers the ancient Mediterranean area, from Mesopotamia to the Iberian Peninsula and from prehistoric communities to classic societies, with Mesopotamian, Phoenician and Iberian examples. A multidisciplinary approach is adopted, analysing material culture, representations and texts to gain a deeper understanding of the plurality of motherhood, and the diversity of women’s agency through history.
We investigate nonlinear transport properties of quantum conductors in response to both electrical and thermal driving forces. Within the scattering approach, we determine the nonequilibrium ...screening potential of a generic mesoscopic system and find that its response is dictated by particle and entropic injectivities which describe the charge and entropy transfer during transport. We illustrate our model analyzing the voltage and thermal rectification of a resonant tunneling barrier. Importantly, we discuss interaction induced contributions to the thermopower in the presence of large temperature differences.
Shifting the life cycle of grain crops from annual to perennial would usher in a new era of agriculture that is more environmentally friendly, resilient to climate change, and capable of soil carbon ...sequestration. Despite decades of work, transforming the annual grain crop wheat (Triticum aestivum) into a perennial has yet to be realized. Direct domestication of wild perennial grass relatives of wheat, such as Thinopyrum intermedium, is an alternative approach. Here we highlight protein coding sequences in the recently released T. intermedium genome sequence that may be orthologous to domestication genes identified in annual grain crops. Their presence suggests a roadmap for the accelerated domestication of this plant using new breeding technologies.
Current grain crops are annuals that must be sown every year, giving their root systems little time to develop during the growing season.A perennial grain crop with a long-lived extensive root system would improve soil quality, store carbon belowground, and utilize water and minerals more efficiently.Domestication genes of the annual grass wheat are highly conserved in the perennial intermediate wheatgrass (Thinopyrum intermedium), providing an opportunity for accelerated domestication of a perennial grain using a mutagenesis approach.
Summary
The aim of this review was to undertake a survey of researchers working with plant‐parasitic nematodes in order to determine a ‘top 10’ list of these pathogens based on scientific and ...economic importance. Any such list will not be definitive as economic importance will vary depending on the region of the world in which a researcher is based. However, care was taken to include researchers from as many parts of the world as possible when carrying out the survey. The top 10 list emerging from the survey is composed of: (1) root‐knot nematodes (Meloidogyne spp.); (2) cyst nematodes (Heterodera and Globodera spp.); (3) root lesion nematodes (Pratylenchus spp.); (4) the burrowing nematode Radopholus similis; (5) Ditylenchus dipsaci; (6) the pine wilt nematode Bursaphelenchus xylophilus; (7) the reniform nematode Rotylenchulus reniformis; (8) Xiphinema index (the only virus vector nematode to make the list); (9) Nacobbus aberrans; and (10) Aphelenchoides besseyi. The biology of each nematode (or nematode group) is reviewed briefly.
N,N‐Diacylaminals are flexible molecular scaffolds that have commonly been utilized as amide surrogates in peptidomimetics. The singularities of this motif as an N‐acyl imine equivalent and as ...hydrogen‐bond donor have recently opened new synthetic opportunities, especially in the field of asymmetric catalysis. This concept article highlights this diverse synthetic potential and provides the elements necessary for further developments.
N,N‐Diacylaminals are flexible molecular scaffolds that have commonly been utilized as amide surrogates in peptidomimetics. This Concept article highlights the utility of the N,N‐diacylaminal unit in asymmetric catalysis beyond its traditional use in peptidomimetic chemistry.
We investigate nonlinear heat properties in mesoscopic conductors using a scattering theory of transport. Our approach is based on a leading-order expansion in both the electrical and thermal driving ...forces. Beyond linear response, the transport coefficients are functions of the nonequilibrium screening potential that builds up in the system due to interactions. Within a mean-field approximation, we self-consistently calculate the heat rectification properties of a quantum dot attached to two terminals. We discuss nonlinear contributions to the Peltier effect and find departures from the Wiedemann-Franz law in the nonlinear regime of transport.
The production of chiral pyrrolodiketopiperazines under organocatalytic conditions demonstrates the capacity of bicyclic acylpyrrol lactims to perform as pronucleophiles in direct carbon–carbon bond ...forming reactions. The good performance of ureidoaminal-derived Brønsted bases in the Michael addition to nitroolefins affords these heterocyclic scaffolds with high skeleton diversity.
We review recent developments in nonlinear quantum transport through nanostructures and mesoscopic systems driven by thermal gradients or in combination with voltage biases. Low-dimensional ...conductors are excellent platforms for analyzing both the thermoelectric and heat dynamics beyond the linear response because, due to their small size, a small temperature difference applied across regions gives rise to large thermal biases. We offer a theoretical discussion based on the scattering approach to highlight the differences between the linear and the nonlinear regimes of transport. We discuss recent experiments on quantum dots and molecular junctions subjected to strong temperature differences. Theoretical predictions concerning the Kondo effect and heat rectification proposals are briefly examined. An important issue is the calculation of thermoelectric efficiencies including nonlinearities. Cross Seebeck effects and nonlinear spin filtering arise in superconductors and topological insulators, while mixed noises between charge and heat currents are also considered. Finally, we provide an outlook on the possible future directions of the field.
Nous passons en revue les dévelopements récents relatifs au transport au travers de nanostructures et de systèmes mésoscopiques, engendré par des combinaisons de gradients de température et/ou de potentiel. Les conducteurs de basses dimensions constituent d'excellents systèmes pour étudier les dynamiques thermoélectrique et thermique au-delà de la réponse linéaire, une petite différence de température engendrant de forts gradients thermiques du fait des petites tailles. Nous présentons une théorie basée sur une approche de scattering pour illustrer les différences entre les régimes de transport linéaire et non linéaire. Nous discutons des expériences récentes sur des boîtes quantiques ou des jonctions moléculaires soumises à de fortes différences de température. Des prédictions théoriques relatives à l'effet Kondo et à la rectification du transport thermique sont brièvement examinées. Un point important est le calcul des rendements thermoélectriques en présence de non-linéarités. Nous coinsidérons aussi des effets Seebeck croisés avec du filtrage de spin non linéaire qui se produisent dans des supraconducteurs et des isolants topologiques, et le mélange des bruits de courant de charge et de chaleur. Finalement, nous discutons les directions futures possibles dans ce domaine.
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