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In this contribution, we present "Birch‐type", and other reductions of simple arenes by the potassium salt of an anionic magnesium dinitrogen complex, [{K(TCHPNON)Mg}2(μ‐N2)] (TCHPNON=4,5‐bis(2,4,6‐tricyclohexylanilido)‐2,7‐diethyl‐9,9‐dimethyl‐xanthene), which acts as a masked dimagnesium(I) diradical in these reactions. This reagent is non‐hazardous, easy‐to‐handle, and in some cases provides access to 1,4‐cyclohexadiene reduction products under relatively mild reaction conditions. This system works effectively to reduce benzene, naphthalene and anthracene through magnesium‐bound "Birch‐type" reduction intermediates. Cyclohexadiene products can be subsequently released from the magnesium centres by protonolysis with methanol. In contrast, the reduction of substituted arenes is less selective and involves competing reaction pathways. For toluene and 1,3,5‐triphenylbenzene, the structural authentication of "Birch‐type" reduction intermediates is conclusive, although the formation of corresponding 1,4‐cyclohexadiene derivatives was low yielding. Reduction of anisole did not yield an isolable "Birch‐type" intermediate, but instead gave a C−O activation product. Treating triphenylphosphine with [{K(TCHPNON)Mg}2(μ‐N2)] resulted in the extrusion of both biphenyl and dinitrogen to afford a magnesium(II) phosphanide [{K(TCHPNON)Mg(μ‐PPh2)}2]. Reduction of fluorobenzene proceeded via C−F activation of the arene, and isolation of the magnesium(II) fluoride [{K(TCHPNON)Mg(μ‐F)}2]. Finally, the two‐electron reduction of 1,3,5,7‐cyclooctatetraene (COT) with [{K(TCHPNON)Mg}2(μ‐N2)] yielded a complex, [{K(TCHPNON)Mg}2(μ‐COT)], incorporating the aromatic dianion (COT2−). [ABSTRACT FROM AUTHOR]

Seven inscriptions from Oine on Ikaria that refer to Samians residing on the island have long been used to argue the case for Samian political control over Ikaria. This article seeks to reassess what these inscriptions tell us about Samian–Ikarian interactions by exploring different models of connectivity for the two islands. Specifically, this article considers short-range mobility, and the capacity of each island to perform various political functions. [ABSTRACT FROM AUTHOR]

Numerous industrial processes utilise gaseous chemical feedstocks to produce useful chemical products. Atmospheric and other small molecule gases, including anthropogenic waste products (e.g. carbon dioxide), can be viewed as sustainable building blocks to access value-added chemical commodities and materials. While transition metal complexes have been well documented in the reduction and transformation of these substrates, molecular complexes of the terrestrially abundant alkaline earth metals have also demonstrated promise with remarkable reactivity reported towards an array of industrially relevant gases over the past two decades. This review covers low oxidation state and hydrido group 2 complexes and their role in the reduction and transformation of a selection of important gaseous substrates towards value-added chemical products. [ABSTRACT FROM AUTHOR]

The bulky β‐diketiminate ligand frameworks [BDIDCHP]− and [BDIDipp/Ar]− (BDI=[HC{C(Me)2N‐Dipp/Ar}2]− (Dipp=2,6‐diisopropylphenyl (Dipp); Ar=2,6‐dicyclohexylphyenyl (DCHP) or 2,4,6‐tricyclohexylphyenyl (TCHP)) have been developed for the kinetic stabilisation of the first europium (II) hydride complexes, [(BDIDCHP)Eu(μ‐H)]2, [(BDIDipp/DCHP)Eu(μ‐H)]2 and [(BDIDipp/TCHP)Eu(μ‐H)]2, respectively. These complexes represent the first step beyond the current lanthanide(II) hydrides that are all based on ytterbium. Tuning the steric profile of β‐diketiminate ligands from a symmetrical to unsymmetrical disposition, enhanced solubility and stability in the solution–state. This provides the first opportunity to study the structure and bonding of these novel Eu(II) hydride complexes crystallographically, spectroscopically and computationally, with their preliminary reactivity investigated. [ABSTRACT FROM AUTHOR]

Reduction of the magnesium(II) diamide [Mg(TripNON)] (TripNON = 4,5-bis(2,4,6-triisopropylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) with 5% w/w K/KI leads to a good yield of a dianionic dimagnesium(I) species, as its potassium salt, [{K(TripNON)Mg}2]. An X-ray crystallographic analysis shows the molecule to contain a very long Mg–Mg bond (3.137(2) Å). The formation of [{K(TripNON)Mg}2] contrasts with a previously reported reduction of a magnesium(II) complex incorporating a bulkier diamide ligand, which instead afforded a magnesium–dinitrogen complex. In the current study, [{K(TripNON)Mg}2] has been shown to be a viable reagent for the reductive activation of CO, H2 and N2O. [ABSTRACT FROM AUTHOR]

A simple sequential addition protocol for the reductive coupling of ketones and aldehydes by a potassium aluminyl grants access to unsymmetrical pinacolate derivatives. Isolation of an aluminium ketyl complex presents evidence for the accessibility of radical species. Product release from the aluminium centre was achieved using an iodosilane, forming the disilylated 1,2‐diol and a neutral aluminium iodide, thereby demonstrating the steps required to generate a closed synthetic cycle for pinacol (cross) coupling at an aluminyl anion. [ABSTRACT FROM AUTHOR]

The reaction of 9‐diazo‐9H‐fluorene (fluN2) with the potassium aluminyl K[Al(NON)] ([NON]2−=[O(SiMe2NDipp)2]2−, Dipp=2,6‐iPr2C6H3) affords K[Al(NON)(κN1,N3‐{(fluN2)2})] (1). Structural analysis shows a near planar 1,4‐di(9H‐fluoren‐9‐ylidene)tetraazadiide ligand that chelates to the aluminium. The thermally induced elimination of dinitrogen from 1 affords the neutral aluminium ketimide complex, Al(NON)(N=flu)(THF) (2) and the 1,2‐di(9H‐fluoren‐9‐yl)diazene dianion as the potassium salt, [K2(THF)3][fluN=Nflu] (3). The reaction of 2 with N,N'‐diisopropylcarbodiimide (iPrN=C=NiPr) affords the aluminium guanidinate complex, Al(NON){N(iPr)C(N=CMe2)N(CHflu)} (4), showing a rare example of reactivity at a metal ketimide ligand. Density functional theory (DFT) calculations have been used to examine the bonding in the newly formed [(fluN2)2]2− ligand in 1 and the ketimide bonding in 2. The mechanism leading to the formation of 4 has also been studied using this technique. [ABSTRACT FROM AUTHOR]

The activation of dinitrogen (N2) by transition metals is central to the highly energy intensive, heterogeneous Haber–Bosch process. Considerable progress has been made towards more sustainable homogeneous activations of N2 with d‐ and f‐block metals, though little success has been had with main group metals. Here we report that the reduction of a bulky magnesium(II) amide [(TCHPNON)Mg] (TCHPNON=4,5‐bis(2,4,6‐tricyclohexylanilido)‐2,7‐diethyl‐9,9‐dimethyl‐xanthene) with 5 % w/w K/KI yields the magnesium‐N2 complex [{K(TCHPNON)Mg}2(μ‐N2)]. DFT calculations and experimental data show that the dinitrogen unit in the complex has been reduced to the N22− dianion, via a transient anionic magnesium(I) radical. The compound readily reductively activates CO, H2 and C2H4, in reactions in which it acts as a masked dimagnesium(I) diradical. [ABSTRACT FROM AUTHOR]

The activation of dinitrogen (N2) by transition metals is central to the highly energy intensive, heterogeneous Haber–Bosch process. Considerable progress has been made towards more sustainable homogeneous activations of N2 with d‐ and f‐block metals, though little success has been had with main group metals. Here we report that the reduction of a bulky magnesium(II) amide [(TCHPNON)Mg] (TCHPNON=4,5‐bis(2,4,6‐tricyclohexylanilido)‐2,7‐diethyl‐9,9‐dimethyl‐xanthene) with 5 % w/w K/KI yields the magnesium‐N2 complex [{K(TCHPNON)Mg}2(μ‐N2)]. DFT calculations and experimental data show that the dinitrogen unit in the complex has been reduced to the N22− dianion, via a transient anionic magnesium(I) radical. The compound readily reductively activates CO, H2 and C2H4, in reactions in which it acts as a masked dimagnesium(I) diradical. [ABSTRACT FROM AUTHOR]

Background: Opioid overdose deaths in the U.S. continue to increase, largely due to the prevalence of fentanyl, a very powerful opioid, in the illicit drug supply. Buprenorphine treatment is effective for treating opioid use disorder, but it can be challenging for clinicians to introduce buprenorphine treatment to people who use fentanyl due to risks of precipitated withdrawal. Induction could be facilitated through a buprenorphine microdosing approach called "the Bernese method." Objective: In this commentary, we describe how federal laws inadvertently limit optimal use of the Bernese method and how federal laws could be reformed to facilitate use of the Bernese method. Results: The Bernese method requires patients to continue using the opioid of misuse (e.g., fentanyl) for seven to ten days while receiving very low doses of buprenorphine. Under federal law, the typical office-based buprenorphine prescriber can neither prescribe nor administer fentanyl short-term for buprenorphine induction purposes, essentially forcing patients to continue to temporarily obtain fentanyl via the illicit market. Conclusion: The federal government has already indicated its support for increasing buprenorphine access. We argue that the government should permit short-term dispensing of fentanyl to office-based patients undergoing buprenorphine induction. [ABSTRACT FROM AUTHOR]

Reduction of the heteroleptic Ln(III) precursors [Ln(Tp)2(OTf)] (Tp = hydrotris(1-pyrazolyl)borate; OTf = triflate) with either an aluminyl(I) anion or KC8 yielded the adduct-free homoleptic Ln(II) complexes dimeric 1-Eu [{Eu(Tp)(μ-κ1:η5-Tp)}2] and monomeric 1-Yb [Yb(Tp)2]. Complexes 1-Ln have good solubility and stability in both non-coordinating and coordinating solvents. Reaction of 1-Ln with 2 Ph3PO yielded 1-Ln(OPPh3)2. All complexes are intensely coloured and 1-Eu is photoluminescent. The electronic absorption data show the 4f–5d electronic transitions in Ln(II). Single-crystal X-ray diffraction data reveal first μ-κ1:η5-coordination mode of the unsubstituted Tp ligand to lanthanides in 1-Eu. [ABSTRACT FROM AUTHOR]

The chemistry of low valent p-block metal complexes continues to elicit interest in the research community, demonstrating reactivity that replicates and in some cases exceeds that of their more widely studied d-block metal counterparts. The introduction of the first aluminyl anion, a complex containing a formally anionic Al(I) centre charge balanced by an alkali metal (AM) cation, has established a platform for a new area of chemical research. The chemistry displayed by aluminyl compounds is expanding rapidly, with examples of reactivity towards a diverse range of small molecules and functional groups now reported in the literature. Herein we present an account of the structure and reactivity of the growing family of aluminyl compounds. In this context we examine the structural relationships between the aluminyl anion and the AM cations, which now include examples of AM = Li, Na, K, Rb and Cs. We report on the ability of these compounds to engage in bond-breaking and bond-forming reactions, which is leading towards their application as useful reagents in chemical synthesis. Furthermore we discuss the chemistry of bimetallic complexes containing direct Al–M bonds (M = Li, Na, K, Mg, Ca, Cu, Ag, Au, Zn) and compounds with Al–E multiple bonds (E = NR, CR2, O, S, Se, Te), where both classes of compound are derived directly from aluminyl anions. [ABSTRACT FROM AUTHOR]

Building on a pre-existing line of inquiry where the presence of solid particle attractors in thermovibrationally driven flows was demonstrated in cavities subjected to a unidirectional temperature gradient, the present work considers cases where the direction of such a gradient is allowed to change inside the fluid. Moreover, the considered configurations differ with regard to the angle that vibrations form with respect to a reference axis. Variations in the orientation of the temperature gradient are made possible by setting a non-uniform temperature distribution along certain walls. The relationship between the multiplicity (N) of the loci of particle attraction and the inhomogeneities in the temperature field is studied. It is shown that N can exceed the limit N = 2 found in earlier studies and that a zoo of new particle accumulation structures show up, whose ranges of existence depend on the amplitude and frequency of vibrational acceleration, the particle Stokes number, the orientation of vibrations, and the number of inversions in the direction of the temperature gradient. [ABSTRACT FROM AUTHOR]

The reaction of compounds containing Al–Mg and Al–Zn bonds with N2O enabled isolation of the corresponding Al(μ-O)M complexes. Electronic structure analysis identified largely ionic Al–O and O–M bonds, featuring an anionic μ-oxo centre. Reaction with CO2 confirmed that these species correspond to the proposed intermediates in the formation of μ-carbonate compounds. [ABSTRACT FROM AUTHOR]

• New sterically bulky aryl and aliphatic substituted diamide ligands have been reported. • A series of novel germylenes were prepared and their steric profile assessed using computational models. • The extremely bulky 2,4,6-tricyclohexylphenyl substituent provides greater steric protection to the germanium centre, compared to previously reported germylenes incorporating smaller aryl groups, utilising the same ligand back-bone architectures. In this contribution, three novel diamine pro-ligands, incorporating sterically bulky aryl and aliphatic N-substituents, have been developed; viz. (NCNTCHP)H 2 (NCNTCHP = {(TCHP)NCH 2 } 2 CH 2 , TCHP = 2,4,6-tricyclohexylphenyl), (NONTCHP)H 2 (NONTCHP = {(TCHP)NSiMe 2 } 2 O), and (NONAd)H 2 (NONAd = {(Ad)NSiMe 2 } 2 O; Ad = 1-adamantyl). Through salt metathesis or transamination synthetic approaches, the N-heterocyclic germylenes, [:Ge(NCNTCHP)], [:Ge(NONTCHP)], and [:Ge(NONAd)], have been prepared and crystallographically characterized. The electronic structure of each germylene was studied by DFT calculations. The steric profile of the germanium-bound ligands was also assessed using computational models, and the results compared to those for structurally similar compounds. Significant steric crowding of the germanium centre (>70 % ligand coverage) was observed for [:Ge(NCNTCHP)] and [:Ge(NONTCHP)], while [:Ge(NONAd)] exhibited substantially less steric saturation at the metal centre (∼62 % ligand coverage). Through these studies, we have shown the potential suitably of the developed ligands to stabilise other low-valent main-group species. Synopsis: A range of very bulky 6-membered heterocyclic diamido germylenes were synthesised and their structures investigated using X-ray crystallography and computational methods. [Display omitted] [ABSTRACT FROM AUTHOR]

(NONDipp)Al–K(TMEDA)2 (NONDipp = [O(SiMe2NDipp)2]2−, Dipp = 2,6-iPr2C6H3), containing an Al–K bond, activates and reductively couples cabon monoxide gas to form the [C4O4]4− ligand. This oxocarbon anion is thermally isomerised in the presence of CO and TMEDA. In contrast, the dimeric potassium aluminyl [K{Al(NONDipp)}]2 yields an aluminium complex containing the hitherto unknown [C5O5]5− ligand. [ABSTRACT FROM AUTHOR]

The potassium aluminyl [K{Al(NONDipp)}]2 ([NONDipp]2−=[O{SiMe2NDipp}2]2−, Dipp=2,6‐iPr2C6H3) activates ethene towards carbonylation with CO under mild conditions. An isolated bis‐aluminacyclopropane compound reacted with CO via carbonylation of an Al−C bond, followed by an intramolecular hydrogen shift to form K2[Al(NONDipp)(μ‐CH2CH=CO‐1κ2C1,3‐2κO)Al(NONDipp)Et]. Restricting the chemistry to a mono‐aluminium system allowed isolation of [Al(NONDipp)(CH2CH2CO‐κ2C1,3)]−, which undergoes thermal isomerisation to form the [Al(NONDipp)(CH2CH=CHO‐κ2C,O)]− anion. DFT calculations highlight the stabilising influence of incorporated benzene at multiple steps in the reaction pathways. [ABSTRACT FROM AUTHOR]

The potassium aluminyl [K{Al(NONDipp)}]2 ([NONDipp]2−=[O{SiMe2NDipp}2]2−, Dipp=2,6‐iPr2C6H3) activates ethene towards carbonylation with CO under mild conditions. An isolated bis‐aluminacyclopropane compound reacted with CO via carbonylation of an Al−C bond, followed by an intramolecular hydrogen shift to form K2[Al(NONDipp)(μ‐CH2CH=CO‐1κ2C1,3‐2κO)Al(NONDipp)Et]. Restricting the chemistry to a mono‐aluminium system allowed isolation of [Al(NONDipp)(CH2CH2CO‐κ2C1,3)]−, which undergoes thermal isomerisation to form the [Al(NONDipp)(CH2CH=CHO‐κ2C,O)]− anion. DFT calculations highlight the stabilising influence of incorporated benzene at multiple steps in the reaction pathways. [ABSTRACT FROM AUTHOR]

Expanding knowledge of low valent aluminium chemistry, rubidium and caesium aluminyls are reported to complete the group 1 (Li–Cs) set of metal aluminyls. Both compounds crystallize as a contacted dimeric pair supported by M⋯π(arene) interactions with a pronounced twist between aluminyl units. Density functional theory calculations show symmetrical bonding between the M and Al atoms, with an Al centred lone-pair donating into vacant Rb and Cs orbitals. Interestingly, despite their structural similarity the Cs aluminyl enables C–H bond activation of benzene, but not the Rb aluminyl reflecting the importance of the alkali metal in these heterobimetallic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] Yttrium alkyl complex [NONDippY(CH 2 SiMe 3)(THF)], 1 (NONDipp = (DippNSiMe 2) 2 O, Dipp = 2,6- i Pr-C 6 H 3) can be prepared in high yields by a σ-bond metathesis reaction between [Y(CH 2 SiMe 3) 3 (THF) 2 ] and the free bis(aminosilyl)ether. The reaction of 1 with one equivalent of PhSiH 3 generates the hydride bridged yttrium dimer [μ-NONDippY(μ-H)(THF)] 2 2 , however, each diamidosilylether ligand does not chelate each yttrium centre but instead bridges to both yttrium atoms in a "flyover" fashion. This ligand rearrangement maybe reversed by the addition of a strong Lewis base to give the dimeric yttrium hydride [NONDippY(μ-H)(DMAP)] 2 3 , where each diamidosilylether ligand now chelate to each yttrium center respectively. The effect of the different diamidosilylether bonding modes on the reactivity of the yttrium complexes is examined with heterocumulenes. Yttrium alkyl complex [NONDippY(CH 2 SiMe 3)(THF)], 1 (NONDipp = (DippNSiMe 2) 2 O, Dipp = 2,6- i Pr-C 6 H 3) can be prepared in high yields by a σ-bond metathesis reaction between [Y(CH 2 SiMe 3) 3 (THF) 2 ] and the free bis(aminosilyl)ether. The reaction of 1 with one equivalent of PhSiH 3 generates the hydride bridged yttrium dimer [μ-NONDippY(μ-H)(THF)] 2 2 , however, each diamidosilylether ligand does not chelate each yttrium centre but instead bridges to both yttrium atoms in a "flyover" fashion. This ligand rearrangement maybe reversed by the addition of a strong Lewis base to give the dimeric yttrium hydride [NONDippY(μ-H)(DMAP)] 2 3 , where each diamidosilylether ligand now chelate to each yttrium center respectively. The effect of the different diamidosilylether bonding modes on the reactivity of the yttrium complexes is examined with heterocumulenes. [ABSTRACT FROM AUTHOR]

To date, aluminyl anions have been exclusively isolated as their potassium salts. We report herein the synthesis of the lithium and sodium aluminyls, M2[Al(NONDipp)]2 (M=Li, Na. NONDipp=[O(SiMe2NDipp)2]2−; Dipp=2,6‐iPr2C6H3). Both compounds crystallize from non‐coordinating solvent as "slipped" contacted dimeric pairs with strong M⋅⋅⋅π(aryl) interactions. Isolation from Et2O solution affords the monomeric ion pairs (NONDipp)Al‐M(Et2O)2, which contain discrete Al−Li and Al−Na bonds. The ability of the full series of Li, Na and K aluminyls to activate dihydrogen is reported. [ABSTRACT FROM AUTHOR]

To date, aluminyl anions have been exclusively isolated as their potassium salts. We report herein the synthesis of the lithium and sodium aluminyls, M2[Al(NONDipp)]2 (M=Li, Na. NONDipp=[O(SiMe2NDipp)2]2−; Dipp=2,6‐iPr2C6H3). Both compounds crystallize from non‐coordinating solvent as "slipped" contacted dimeric pairs with strong M⋅⋅⋅π(aryl) interactions. Isolation from Et2O solution affords the monomeric ion pairs (NONDipp)Al‐M(Et2O)2, which contain discrete Al−Li and Al−Na bonds. The ability of the full series of Li, Na and K aluminyls to activate dihydrogen is reported. [ABSTRACT FROM AUTHOR]

Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NONDipp)(H)2] (AM=Li, Na, K, Rb, Cs; [NONDipp]2−=[O(SiMe2NDipp)2]2−; Dipp=2,6‐iPr2C6H3) starting from the alkali metal aluminyls, AM[Al(NONDipp)]. Direct H2 hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4‐cyclohexadiene (1,4‐CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li−Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NONDipp)(H)(SiH2Ph)]. Probing the reaction of Cs[Al(NONDipp)] with 1,4‐CHD provided access to a novel inverse sandwich complex, [{Cs(Et2O)}2{Al(NONDipp)(H)}2(C6H6)], containing the 1,4‐dialuminated [C6H6]2− dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4‐CHD to benzene has been trapped. The synthetic utility of the newly installed Al−H bonds has been demonstrated by their ability to reduce CO2 under mild conditions to form the bis‐formate AM[Al(NONDipp)(O2CH)2] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures. [ABSTRACT FROM AUTHOR]

The maize female gametophyte contains four cell types: two synergids, an egg cell, a central cell, and a variable number of antipodal cells. In maize, these cells are produced after three rounds of free-nuclear divisions followed by cellularization, differentiation, and proliferation of the antipodal cells. Cellularization of the eight-nucleate syncytium produces seven cells with two polar nuclei in the central cell. Nuclear localization is tightly controlled in the embryo sac. This leads to precise allocation of the nuclei into the cells upon cellularization. Nuclear positioning within the syncytium is highly correlated with their identity after cellularization. Two mutants are described with extra polar nuclei, abnormal antipodal cell morphology, and reduced antipodal cell number, as well as frequent loss of antipodal cell marker expression. Mutations in one of these genes, indeterminate gametophyte2 encoding a MICROTUBULE ASSOCIATED PROTEIN65-3 homolog, shows a requirement for MAP65-3 in cellularization of the syncytial embryo sac as well as for normal seed development. The timing of the effects of ig2 suggests that the identity of the nuclei in the syncytial female gametophyte can be changed very late before cellularization. [ABSTRACT FROM AUTHOR]

The ground-based gravitational wave (GW) detectors LIGO and Virgo have enabled the birth of multi-messenger GW astronomy via the detection of GWs from merging stellar-mass black holes (BHs) and neutron stars (NSs). GW170817, the first binary NS merger detected in GWs and all bands of the electromagnetic spectrum, is an outstanding example of the impact that GW discoveries can have on multi-messenger astronomy. Yet, GW170817 is only one of the many and varied multi-messenger sources that can be unveiled using ground-based GW detectors. In this contribution, we summarize key open questions in the astrophysics of stellar-mass BHs and NSs that can be answered using current and future-generation ground-based GW detectors, and highlight the potential for new multi-messenger discoveries ahead. [ABSTRACT FROM AUTHOR]

Cyclopentadienyl ligands are ubiquitous in lanthanide chemistry and have been used extensively to stabilize low-valent lanthanide(II) complexes. We now report the reactions of the β-diketiminate ytterbium(II) hydride [(BDIDipp)Yb(H)]2 (BDIDipp = HC{C(Me)NDipp}2, Dipp = 2,6-iPr2C6H3) with tetramethylcyclopentadiene, pentamethylcyclopentadiene, indene, and fluorene; to provide ready access to the heteroleptic ytterbium(II) η5-C5R5 cyclopentadienides with extrusion of hydrogen gas. The tetramethylcyclopentadienyl, pentamethylcyclopentadienyl, indenyl, and fluorenyl compounds were characterized by 1H and 13C{1H} NMR, elemental analysis, and single crystal X-ray diffraction. These data indicated that each heteroleptic cyclopentadienide exists as a mononuclear species in both solution and the solid state, formulated with retention of the oxidation state on the ytterbium(II) center. Additionally, the pentamethylcyclopentadienyl derivative was characterized by single crystal neutron diffraction, a study that explored the nature of an agostic interaction between a methyl group and the ytterbium(II) center. [ABSTRACT FROM AUTHOR]

The multi-step process of hepatitis C virus (HCV) entry is facilitated by various host factors, including epidermal growth factor receptor (EGFR) and the tight junction proteins claudin-1 (CLDN1) and occludin (OCLN), which are thought to function at later stages of the HCV entry process. Using single particle imaging of HCV infection of polarized hepatoma spheroids, we observed that EGFR performs multiple functions in HCV entry, both phosphorylation-dependent and -independent. We previously observed, and in this study confirmed, that EGFR is not required for HCV migration to the tight junction. EGFR is required for the recruitment of clathrin to HCV in a phosphorylation-independent manner. EGFR phosphorylation is required for virion internalization at a stage following the recruitment of clathrin. HCV entry activates the RAF-MEK-ERK signaling pathway downstream of EGFR phosphorylation. This signaling pathway regulates the sorting and maturation of internalized HCV into APPL1- and EEA1-associated early endosomes, which form the site of virion uncoating. The tight junction proteins, CLDN1 and OCLN, function at two distinct stages of HCV entry. Despite its appreciated function as a "late receptor" in HCV entry, CLDN1 is required for efficient HCV virion accumulation at the tight junction. Huh-7.5 cells lacking CLDN1 accumulate HCV virions primarily at the initial basolateral surface. OCLN is required for the late stages of virion internalization. This study produced further insight into the unusually complex HCV endocytic process. Author summary: Hepatitis C virus (HCV) is a hepatotropic RNA virus. An estimated 58 million people are chronically infected with HCV, while HCV-associated hepatocellular carcinoma and cirrhosis accounted for 290, 000 deaths in 2019. HCV entry into hepatocytes is highly complex with distinct stages and multiple host cofactors. Perturbing the interaction of HCV with entry host factors is potential strategy for therapeutic and vaccine-based anti-HCV approaches. However, the precise functions of most of the host factors in HCV entry are not fully appreciated. Moreover, studies of entry using polarized cell culture that physiologically resembles hepatocytes in vivo are limited. In this paper, we evaluate the roles of three entry factors in polarized hepatoma spheroids: epidermal growth factor receptor (EGFR) and tight junction proteins claudin-1 (CLDN1) and occludin (OCLN). We observe that EGFR performs multiple functions to regulate HCV internalization and trafficking to endosomes. The process involves EGFR phosphorylation-dependent and -independent roles and downstream RAF-MEK-ERK signaling pathway. We also show that CLDN1 and OCLN, despite both localizing at the tight junction, function at two distinct stages of HCV entry. CLDN1 is required for the accumulation of HCV virions at the tight junction from the basolateral membrane, while OCLN regulates HCV internalization. These findings provide insights into the mechanism of HCV entry and highlight potential interventional strategies. [ABSTRACT FROM AUTHOR]

Zika virus and dengue virus are co-circulating flaviviruses with a widespread endemic range. Eliciting broad and potent neutralizing antibodies is an attractive goal for developing a vaccine to simultaneously protect against these viruses. However, the capacity of viral mutations to confer escape from broadly neutralizing antibodies remains undescribed, due in part to limited throughput and scope of traditional approaches. Here, we use deep mutational scanning to map how all possible single amino acid mutations in Zika virus envelope protein affect neutralization by antibodies of varying breadth and potency. While all antibodies selected viral escape mutations, the mutations selected by broadly neutralizing antibodies conferred less escape relative to those selected by narrow, virus-specific antibodies. Surprisingly, even for broadly neutralizing antibodies with similar binding footprints, different single mutations led to escape, indicating distinct functional requirements for neutralization not captured by existing structures. Additionally, the antigenic effects of mutations selected by broadly neutralizing antibodies were conserved across divergent, albeit related, flaviviruses. Our approach identifies residues critical for antibody neutralization, thus comprehensively defining the as-yet-unknown functional epitopes of antibodies with clinical potential. [ABSTRACT FROM AUTHOR]

Background and Aims Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model. Methods The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus. Key Results The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission. Conclusions Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification. [ABSTRACT FROM AUTHOR]

• Molecular testing is critical in patients with NSCLC to personalise therapy options. • Genomic Laboratory Hubs in England deliver genomic testing for NSCLC. • Challenges with genomic testing include tissue quality/quantity and turnaround times. • Recommendations include optimising sample acquisition/processing, MDT communication. Targeted therapy against actionable variants has revolutionised the treatment landscape for non-small cell lung cancer (NSCLC). Approximately half of NSCLC adenocarcinomas have an actionable variant, making molecular testing a critical component of the diagnostic process to personalise therapeutic options, optimise clinical outcomes and minimise toxicity. Recently, genomic testing in England has undergone major changes with the introduction of Genomic Laboratory Hubs, designed to consolidate and enhance existing laboratory provision and deliver genomic testing as outlined in the National Genomic Test Directory. Similar changes are ongoing in Scotland, Wales and Northern Ireland. However, multiple challenges exist with current tissue acquisition procedures and the molecular testing pathway in the UK, including quantity and quality of available tissue, adequacy rates, test availability among genomic laboratories, turnaround times, multidisciplinary team communication, and limited guidance and standardisation. The COVID-19 pandemic has added an extra layer of complexity. Herein, we summarise best practice recommendations, based on expert opinion, to overcome existing challenges in the UK. The least invasive biopsy technique should be undertaken with the aim of acquiring the greatest quality and quantity of tissue. Use of sedation should be considered to improve patient experience. Rapid on-site evaluation may also be useful to help guide adequate sampling, and liquid biopsy may be beneficial in some instances. Sample processing should be appropriate to facilitate biomarker testing, in particular, next-generation sequencing for comprehensive genomic information. Steps to optimise tissue utilisation and turnaround times, such as planning of tissue usage, limiting immunohistochemistry, tumour enrichment, and reflex testing at diagnosis, should be implemented. Guidelines for tissue acquisition and sample processing may help to improve sample adequacy to perform downstream testing. Communication among genomic laboratories will help to standardise test availability across England and local auditing could identify further areas for optimisation, including ways to improve turnaround times and adequacy rates. [ABSTRACT FROM AUTHOR]

• Target enrichment can directly sequence host-associated fungal pathogens. • Fungal pathogen load is positively associated with enrichment success. • Resulting genetic data can identify phylogenetic placements of fastidious strains. • Salamander at US zoo was infected with Asian-origin Batrachochytrium strain. • Method can be applied to other unculturable fungal samples to identify cryptic strains. The chytrid fungus Batrachochytrium dendrobatidis (Bd) was discovered in 1998 as the cause of chytridiomycosis, an emerging infectious disease causing mass declines in amphibian populations worldwide. The rapid population declines of the 1970s-1990s were likely caused by the spread of a highly virulent lineage belonging to the Bd-GPL clade that was introduced to naïve susceptible populations. Multiple genetically distinct and regional lineages of Bd have since been isolated and sequenced, greatly expanding the known biological diversity within this fungal pathogen. To date, most Bd research has been restricted to the limited number of samples that could be isolated using culturing techniques, potentially causing a selection bias for strains that can grow on media and missing other unculturable or fastidious strains that are also present on amphibians. We thus attempted to characterize potentially non-culturable genetic lineages of Bd from distinct amphibian taxa using sequence capture technology on DNA extracted from host tissue and swabs. We focused our efforts on host taxa from two different regions that likely harbored distinct Bd clades: (1) wild-caught leopard frogs (Rana) from North America, and (2) a Japanese Giant Salamander (Andrias japonicus) at the Smithsonian Institution's National Zoological Park that exhibited signs of disease and tested positive for Bd using qPCR, but multiple attempts failed to isolate and culture the strain for physiological and genetic characterization. We successfully enriched for and sequenced thousands of fungal genes from both host clades, and Bd load was positively associated with number of recovered Bd sequences. Phylogenetic reconstruction placed all the Rana -derived strains in the Bd-GPL clade. In contrast, the A. japonicus strain fell within the Bd-Asia3 clade, expanding the range of this clade and generating additional genomic data to confirm its placement. The retrieved ITS locus matched public barcoding data from wild A. japonicus and Bd infections found on other amphibians in India and China, suggesting that this uncultured clade is widespread across Asia. Our study underscores the importance of recognizing and characterizing the hidden diversity of fastidious strains in order to reconstruct the spatiotemporal and evolutionary history of Bd. The success of the sequence capture approach highlights the utility of directly sequencing pathogen DNA from host tissue to characterize cryptic diversity that is missed by culture-reliant approaches. [ABSTRACT FROM AUTHOR]

The synthesis and structural characterisation of [(NONR)M] (NON=O(SiMe2NR)2]2−; R=tBu, Ph, 2,6‐Me2C6H3 (Dmp), 2,6‐iPr2C6H3 (Dipp); M=Ge, Sn, Pb) is described. Germanium complexes [(NONPh)Ge], [(NONDmp)Ge] and [(NONDipp)Ge] are monomeric. Tin complexes [(NONPh)Sn]2, [(NONDmp)Sn]2 and [(NONtBu)Sn]2 are dimeric in the solid‐state, with [(NONPh)Sn]2 forming a link through bridging N‐atoms, [(NONDmp)Sn]2 linked through Sn⋅⋅⋅Ar contacts and [(NONtBu)Sn]2 forming the first distannene bearing two amido ligands. In contrast, [(NONDipp)Sn] is monomeric in the solid‐state. The lead complexes [(NONPh)Pb]2 and [(NONDmp)Pb]2 are isostructual with their tin analogues while [(NONtBu)Pb] is monomeric in the solid‐state. Solution phase NMR spectroscopic data suggest that all [(NONR)M] compounds are monomeric in solution. Structural parameters, including buried volume (%Vbur) are discussed. [ABSTRACT FROM AUTHOR]