Deuterated organic compounds have become increasingly important in many areas; however, it remains challenging to install deuterium site-selectively to unactivated aliphatic positions with control of ...the degree of deuteration. Here, we report a Cu-catalyzed degree-controlled deacylative deuteration of diverse alkyl groups with the methylketone (acetyl) moiety as a traceless activating group. The use of N-methylpicolino-hydrazonamide (MPHA) promotes efficient aromatization-driven C–C cleavage. Mono-, di-, and trideuteration at specific sites can be selectively achieved. The reaction is redox-neutral with broad functional group tolerance. The utility of this method has been demonstrated in forming a complete set of deuterated ethyl groups, merging with the Diels–Alder reaction, a net devinylative deuteration, and the synthesis of the d 2-analogue of Austedo.
The genus Mesoneritina was first described to contain a single fossil neritid from the Lower Cretaceous of Nebraska, USA. Further Jurassic and Cretaceous neritids from the USA, Greenland, Europe and ...China were later classified in this genus. However, while the North American species all share similar morphologies, the Chinese forms seem to be a distinct group. In this study, we review the Chinese species presently classified in Mesoneritina and erect a new genus to contain them, Panneritina gen. nov. (with the exception of one species, now classified as Bellamya liaoningensis comb. nov.). We also describe a new species, Panneritina ambrae sp. nov., from the middle Cretaceous Kachin amber of northern Myanmar. The new genus contains the following species: P. ambrae sp. nov., P. crassa, P. dakangensis, P. gansuensis, P. nanshanensis, P. opima, and P. pustula.
Leaf hydraulic conductance (K
leaf) and mesophyll conductance (g
m) both represent major constraints to photosynthetic rate (A), and previous studies have suggested that K
leaf and g
m is correlated ...in leaves. However, there is scarce empirical information about their correlation.
In this study, K
leaf, leaf hydraulic conductance inside xylem (K
x), leaf hydraulic conductance outside xylem (K
ox), A, stomatal conductance (g
s), g
m, and anatomical and structural leaf traits in 11 Oryza genotypes were investigated to elucidate the correlation of H2O and CO2 diffusion inside leaves.
All of the leaf functional and anatomical traits varied significantly among genotypes. K
leaf was not correlated with the maximum theoretical stomatal conductance calculated from stomatal dimensions (g
smax), and neither g
s nor g
smax were correlated with K
x. Moreover, K
ox was linearly correlated with g
m and both were closely related to mesophyll structural traits.
These results suggest that K
leaf and g
m are related to leaf anatomical and structural features, which may explain the mechanism for correlation between g
m and K
leaf.
A newly-discovered fossil gastropod belonging to the family Hydrocenidae is studied using classic light microscopy and modern micro-CT scans with 3D computer reconstructions. ?Hydrocena praecursor ...sp. nov. is the oldest known member of the Hydrocenidae and the only Mesozoic representative of the family in Asia. The present finding supports previous assumptions of a Mesozoic origin of the family and indicates that Hydrocenidae have become fully terrestrial at least by the mid-Cretaceous. Moreover, our discovery implies a much wider fossil distribution of Hydrocenidae than previously assumed.
An ammonite trapped in Burmese amber Yu, Tingting; Kelly, Richard; Mu, Lin ...
Proceedings of the National Academy of Sciences - PNAS,
06/2019, Volume:
116, Issue:
23
Journal Article
Peer reviewed
Open access
Amber is fossilized tree resin, and inclusions usually comprise terrestrial and, rarely, aquatic organisms. Marine fossils are extremely rare in Cretaceous and Cenozoic ambers. Here, we report a ...record of an ammonite with marine gastropods, intertidal isopods, and diverse terrestrial arthropods as syninclusions in mid-Cretaceous Burmese amber. We used X-ray–microcomputed tomography (CT) to obtain high-resolution 3D images of the ammonite, including its sutures, which are diagnostically important for ammonites. The ammonite is a juvenile Puzosia (Bhimaites) and provides supporting evidence for a Late Albian–Early Cenomanian age of the amber. There is a diverse assemblage (at least 40 individuals) of arthropods in this amber sample from both terrestrial and marine habitats, including Isopoda, Acari (mites), Araneae (spiders), Diplopoda (millipedes), and representatives of the insect orders Blattodea (cockroaches), Coleoptera (beetles), Diptera (true flies), and Hymenoptera (wasps). The incomplete preservation and lack of soft body of the ammonite and marine gastropods suggest that they were dead and underwent abrasion on the seashore before entombment. It is most likely that the resin fell to the beach from coastal trees, picking up terrestrial arthropods and beach shells and, exceptionally, surviving the high-energy beach environment to be preserved as amber. Our findings not only represent a record of an ammonite in amber but also provide insights into the taphonomy of amber and the paleoecology of Cretaceous amber forests.
This study aimed to examine how communication modes affect creative idea generation in groups. Three communication mode conditions were created: natural (N), turn-taking (T), and electronic ...brainstorming (E). Participants were randomly recruited and grouped in dyads to solve one alternative uses task (AUT) in each condition, during which functional near-infrared spectroscopy (fNIRS)-based hyperscanning was used to record interpersonal neural responses. No difference was observed in AUT fluency across the three conditions, but AUT uniqueness was higher in the T condition than in the E condition. In addition, AUT uniqueness, AUT fluency, and perspective-taking behaviours increased faster in the T condition than in the other conditions. The T condition also showed higher perspective-taking behaviours than did the other conditions. Moreover, fNIRS data showed higher interpersonal brain synchronisation (IBS) increments at the right angular gyrus in the T condition than in the other conditions, which positively predicted perspective-taking behaviours between individuals during group creativity tasks. These findings indicate that when group members create together while taking turns, both creative performance and interpersonal interaction processes can be stimulated.
•AUT uniqueness was higher in the turn-taking (T) than the electronic brainstorming mode.•Creative performance and perspective-taking behaviour increased faster over time in the T mode than in the other modes.•Perspective-taking behaviour was higher in the T mode than in the other modes.•The IBS increment in the right angular gyrus was higher in the T mode than in the other modes..
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•Exceptional preservation of a land snail in amber captures 99-million-year-old live birth event.•Viviparity in land snails is revealed to be 80 million years older than so far known ...in fossil record.•Viviparity is interpreted as birth strategy of choice during predator hungry mid-Cretaceous era.•Fossilized Burmese amber reveals new species of terrestrial snail, Cretatortulosa gignens n. sp.•Ct scans of mother land snail reveal marshmallow-like body, slime and 5 neonates in Burmese amber.
When seldom life history events serendipitously get documented by exceptional preservation in the fossil record, a unique telescopic opportunity arises for interpreting fossils within their paleoenvironment as well as for understanding ancestral relationships of current life forms. We present a rare glimpse of live birth by a terrestrial mother snail, incidentally, engulfed by amber as she released her young in a tropical forest during the mid-Cretaceous (early Cenomanian). The exceptional finding featuring the preservation of a snail’s 99-million-year-old soft-body together with five neonate shells represents the earliest known fossilized incidence of viviparity in a terrestrial snail. Based on high-resolution photographs and µCT scans, we describe the mother snail as a new species of cyclophoroid, Cretatortulosa gignens sp. nov. Our finding provides remarkable perspectives for interpreting gastropod evolution 80 million years earlier than the fossil record has known up to now. It shows that viviparity was already a relevant reproductive strategy in the Cretaceous, probably increasing the offspring’s survival chance in a predator-lurking tropical forest.
Abstract
Developing highly active and durable electrocatalysts for acidic oxygen evolution reaction remains a great challenge due to the sluggish kinetics of the four-electron transfer reaction and ...severe catalyst dissolution. Here we report an electrochemical lithium intercalation method to improve both the activity and stability of RuO
2
for acidic oxygen evolution reaction. The lithium intercalates into the lattice interstices of RuO
2
, donates electrons and distorts the local structure. Therefore, the Ru valence state is lowered with formation of stable Li-O-Ru local structure, and the Ru–O covalency is weakened, which suppresses the dissolution of Ru, resulting in greatly enhanced durability. Meanwhile, the inherent lattice strain results in the surface structural distortion of Li
x
RuO
2
and activates the dangling O atom near the Ru active site as a proton acceptor, which stabilizes the OOH* and dramatically enhances the activity. This work provides an effective strategy to develop highly efficient catalyst towards water splitting.
In the human body, 50-70 billion cells die every day, resulting in the generation of a large number of apoptotic bodies. However, the detailed biological role of apoptotic bodies in regulating tissue ...homeostasis remains unclear. In this study, we used Fas-deficient MRL/lpr and Caspase 3
mice to show that reduction of apoptotic body formation significantly impaired the self-renewal and osteo-/adipo-genic differentiation of bone marrow mesenchymal stem cells (MSCs). Systemic infusion of exogenous apoptotic bodies rescued the MSC impairment and also ameliorated the osteopenia phenotype in MRL/lpr, Caspase 3
and ovariectomized (OVX) mice. Mechanistically, we showed that MSCs were able to engulf apoptotic bodies via integrin αvβ3 and reuse apoptotic body-derived ubiquitin ligase RNF146 and miR-328-3p to inhibit Axin1 and thereby activate the Wnt/β-catenin pathway. Moreover, we used a parabiosis mouse model to reveal that apoptotic bodies participated in the circulation to regulate distant MSCs. This study identifies a previously unknown role of apoptotic bodies in maintaining MSC and bone homeostasis in both physiological and pathological contexts and implies the potential use of apoptotic bodies to treat osteoporosis.
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