bluuebunny/crossref_metadata_2025 huggingface dataset:
Origins of the
HIVs
and the
AIDS
Outbreaks
Authors: Schneider William H
Published: April 2022

The AIDS pandemic was caused by human immunodeficiency virus (HIV) type 1 group M (HIV‐1M). It is not widely appreciated that there are three other HIV outbreaks that emerged independently in different regions of Africa during the last century. To date, 13 HIV groups have been discovered, but only four of which became major outbreaks to varying degrees. HIV‐1M is responsible for 90% of over 35 million deaths, and the other three epidemic HIVs are estimated to have infected from 25 000 to 750 000 people each. A handful of key determinants explain how and why this happened, including human interaction with the simian sources from which the HIVs emerged, but much more important were new ways that people spread the viruses to one another. The latter included population movement and urbanization, changes in sexual relations, war, and above all new medical procedures (unsterile needles and inadequately tested blood transfusions). The emergence of the viruses and their epidemic spread was not the result of a random mutation but rather depended upon the combination of specific circumstances at different places and times. The AIDS pandemic was not a chance, natural occurrence; it is much more accurately described as a (hu)man‐made disaster.

Key Concepts

The global AIDS pandemic was caused by multiple human immunodeficiency viruses.

The HIVs emerged from different simian immunodeficiency viruses (SIVs) independently in two widely separated regions and at different times, mainly during the early and mid‐twentieth century.

Broader understanding of historical, social, and cultural circumstances is necessary to explain how and why these viruses emerged and became pandemic.

The most important new circumstances causing the emergence of HIV epidemic viruses in the twentieth century were those that facilitated passage of pathogens between humans.

In addition to population movement, urbanization, and changing sexual relations, the most ubiquitous new developments increasing the possibility of adapting viruses to humans were blood transfusions and injections against diseases or for mass vaccination campaigns with insufficiently sterilized needles which were contaminated with as yet undiscovered viruses.
Autosomal Recessive Parkinson' Disease Related to Parkin (
PARK2
) Mutations
Authors: Hatano Taku , Ueno Shin‐Ichi , Okuzumi Ayami , Mori Akio , Oji Yutaka , Hattori Nobutaka
Published: April 2022

Parkinson disease (PD) is a common movement disorder caused by loss of dopaminergic neuronal cells. The molecular mechanisms underlying neuronal degeneration in PD remain unknown; however, it is clear that genetic factors contribute to its pathogenesis. Over 20 genetic loci and causative genes have been identified so far, and many studies have examined their effects on monogenic and sporadic forms of PD. The encoded proteins participate in several cellular functions, including membrane trafficking, and protein and lipid degradation.

Mutations in parkin (
PARK2
) are the most common cause of autosomal recessive early‐onset PD. Parkin functions as an E3 ubiquitin ligase, which monoubiquitinates and polyubiquitinates target proteins. Consequently, parkin participates in multiple cellular processes, such as protein degradation, mitochondrial function, membrane trafficking, lipid metabolism and endoplasmic reticulum stress. Parkin can interact with other familial PD‐associated proteins, possibly within a common pathway that leads to nigral degeneration. There is evidence of a PINK1/parkin pathway involving autophagic mitochondrial degradation. Recent investigations involving imaging and blood biomarkers revealed several alterations associated with parkin dysfunction.

Key Concepts

Parkinson disease
(
PD
) is the second most frequent neurodegenerative disease after Alzheimer disease.

Approximately 5% of PD patients have a clear familial aetiology, exhibiting a classical recessive or dominant Mendelian mode of inheritance.

Parkin (
PARK2
) is the most prevalent gene associated with early‐onset Parkinsonism and is associated with approximately 50% of recessive familial patients with an onset under 45 years of age.

Abnormal imaging and blood biomarkers are associated with parkin dysfunction.

Parkin functions as an E3 ubiquitin ligase, which participates in the
ubiquitin–proteasome
(
Ub‐Pr
) system.

Collaboration between parkin and PINK1 promotes the autophagic degradation of damaged mitochondria.

Parkin can participate in several pathways that lead to dopaminergic neuronal degeneration, such as the Ub‐Pr system, autophagic protein degradation, the mitochondrial quality control system, the membrane trafficking system and lipid metabolism.
Exceptional Preservation of Fossil Soft Tissues
Authors: Clements Thomas , Gabbott Sarah
Published: April 2022

Exceptionally preserved soft tissues yield much more information about ancient organisms than skeletal remains alone. These fossils are rare, because, generally, the postmortem processes of decay rapidly strip away information from a carcass before preservation can occur. However, if certain environmental conditions are present that slow the normal recycling of organic material, there is a possibility that soft tissues can become geologically stabilised by the processes of mineralisation or maturation. In order to understand the biological, environmental, and geological factors that control soft tissue preservation, palaeobiologists combine the study of fossil material with laboratory experiments that decay organisms in strictly controlled environmental conditions. These experimental investigations have enhanced our understanding of the inherent biases of the fossil record, and allow more accurate reconstructions of ancient organisms and a better understanding of evolution and ecology. New techniques and cutting‐edge analytical equipment are revolutionising the field, opening up exciting new avenues of palaeontological research such as the identification of fossilised pigments and palaeoproteins.

Key Concepts

Fossils that have soft tissues generally provide more information about ancient organisms than skeletal remains alone.

Organisms undergo varying amounts of decay prior to preservation.

Conservation‐Lagerstätten are sites where depositional environmental conditions disrupted the normal rapid recycling of organic material (e.g. decay) allowing soft tissues to preserve.

Conservation‐Lagerstätten are important not only because they preserve soft‐bodied organisms that are extremely rare in the fossil record but also because they tend to preserve a great diversity of organisms, making them vital windows into the ancient past.

Many sedimentary Conservation‐Lagerstätten share characteristics of rapid burial, low oxygen, and the early onset of diagenetic processes such as mineralisation and/or maturation.

Another type of Conservation‐Lagerstätten are natural traps, such as amber or permafrost, but comparatively, these are geologically young.

The study of burial and preservation is termed taphonomy.

Since the 1980s, laboratory experiments have been undertaken to understand the drivers of soft‐tissue preservation.

Rather than recreating fossils or ancient environments in the lab, robust taphonomic experiments investigate the effect of discrete variables on taphonomic processes.

New avenues in taphonomic investigation are opening up with the advent of new technology and laboratory equipment.
High‐Performance Freshwater Harvesting System by Coupling Solar Desalination and Fog Collection with Hierarchical Porous Microneedle Arrays
Authors: Zhou Wei , Zhou Cailong , Deng Chengfei , Chen Li , Zeng Xinjuan , Zhang Yaoxin , Tan Luxi , Hu Baoshan , Guo Shuai , Dong Lichun , Tan Swee Ching
Published: April 2022

The maximizing daily freshwater yield on the ocean surface necessitates all‐day water harvesting technologies and materials. This is realizable by taking advantage of the natural sunlight and humid air, which can drive daytime solar desalination and nighttime fog collection, respectively. To this end, two types of hierarchically porous microneedle array structures, which demonstrate superior capabilities for efficient fog capturing and photothermal evaporation, respectively, are prepared. The gel‐forged microneedle arrays with Janus wettability are fabricated via a simple and controllable top‐down micro‐molding process on a porous platform, and porosity within microneedles is further achieved readily by additional freeze‐drying treatment. The developed microneedle structure shows an ultrahigh fog harvesting rate up to 30.5 kg m−2 h−1, enabling high flux water droplet harvesting from moisture during nighttime. In the daytime, a solar evaporation rate of 2.46 kg m−2 h−1 is realized due to the increased evaporative area of the porous microneedle arrays and enhanced photothermal conversion. By uniting these two water‐harvesting routes, a daily cycle can ideally deliver an overall water yield close to 200 kg m−2, which will offer a promising solution for sustaining future low‐cost and decentralized clean water production.
A Real‐Time Self‐Adaptive Thermal Metasurface
Authors: Guo Jun , Xu Guoqiang , Tian Di , Qu Zhiguo , Qiu Cheng‐Wei
Published: April 2022

Emerging metamaterials have served as an efficient strategy for the realization of unconventional heat control and management using structural thermal properties, and many functional thermal metadevices have been investigated. However, thermal functions are usually fixed or limited in the switching range. Thus far, real‐time thermal regulation is elusive for thermal metamaterials because of deterministic artificial metastructures and uncontrollable phase transitions, coupled with the absence of dynamic adaptability. Here, a self‐adaptive metasurface platform to implement programmable thermal functions via the automatic evolution of thermoelectric heat sources and real‐time control of the driven voltage is reported. The proof‐of‐concept smart platform experimentally demonstrates arbitrary switching between elaborate thermal patterns consolidated into an active thermoelectric element matrix. Further, thermal pixels and feedback control systems are integrated into printed circuit boards, resulting in self‐adaptability to any thermal requirements. This study sets up a new paradigm for arbitrary transitions between exquisite thermal patterns and is expected to pave the way for real‐time thermal management in a programming formation.
MOF–COF “Alloy” Membranes for Efficient Propylene/Propane Separation
Authors: Liu Yutao , Wu Hong , Li Runlai , Wang Jianyu , Kong Yan , Guo Zheyuan , Jiang Haifei , Ren Yanxiong , Pu Yunchuan , Liang Xu , Pan Fusheng , Cao Yu , Song Shuqing , He Guangwei , Jiang Zhongyi
Published: April 2022

Molecular‐sieving membranes from metal–organic frameworks (MOFs) are promising candidates for separating olefin/paraffin mixtures, a critical demand in sustainable chemical processes and a grand challenge in molecular separation. Currently, the inherent lattice flexibility of MOFs severely compromises their precise sieving ability. Here, a proof‐of‐concept of “alloy” membranes (AMs), which are fabricated by incorporating quaternary ammonium (QA)‐functionalized covalent organic frameworks (COFs) into a zeolitic imidazolate framework‐8 (ZIF‐8) matrix is demonstrated. The Coulomb force between the COFs and the ZIF‐8 restricts the linker rotation of the ZIF‐8, generating a distinct alloying effect, by which the lattice rigidity of ZIF‐8 can be conveniently tuned through varying the content of the COFs, similar to the flexible‐to‐rigid transition in aluminum alloy manufacturing. Such an alloying effect confers the AM's superior propylene/propane separation performance, with a propylene/propane separation factor surpassing 200 and a propylene permeance of 168 GPU. Hopefully, the AMs concept and the concomitant alloying effect can update the connotation of mixed matrix membranes and stimulate the re‐envisioning about the design paradigm and development of advanced membranes for energy‐efficient separations.
2D SnSe Cathode Catalyst Featuring an Efficient Facet‐Dependent Selective Li2O2 Growth/Decomposition for Li–Oxygen Batteries
Authors: Zhang Guoliang , Li Gaoyang , Wang Jun , Tong Hui , Wang Jianchuan , Du Yong , Sun Shuhui , Dang Feng
Published: April 2022

2D materials are attracting much attention in the field of cathode catalysts for lithium–oxygen batteries (LOBs) due to their layered structure, unique electronic properties, and high stability. However, different stacking layer structures trigger different catalytic capabilities in LOBs. In this work, tin selenide nanosheets with a black phosphorus‐like 2D structure are synthesized and used as the cathode catalyst for LOBs. SnSe nanosheets with exposed stack (200) facets and stack edge facets exhibit superior specific capacity over 20 783 mAh g−1 and ultralong cycle stability over 380 cycles at 500 mA g−1 in LOBs. This demonstrates that the growth of discharge products is mainly concentrated on the 2D surface (200) facets, rather than the stack edge facets. Experimental and theoretical studies reveal that the confined adsorption of Li2O2 on the stack edge facets of SnSe, due to the 2D layer structure and the unique electron distribution, restricts the growth of discharge products. The 2D surface facets of SnSe benefit for the formation and stabilization of LiO2 intermediates, leading to the efficient formation/decomposition of discharge products. The findings provide in‐depth insight into the elusive electrocatalytic mechanism for 2D layer‐structures materials in LOBs.
Manipulative repertoire of bonobos (Pan paniscus) in spontaneous feeding situation
Authors: Gérard Caroline , Bardo Ameline , Guéry Jean P. , Pouydebat Emmanuelle , Simmen Bruno , Narat Victor
Published: April 2022

Comparative behavioral studies of hand use amongst primate species, including humans, have been central in research on evolutionary mechanisms. In particular, the manipulative abilities of our closest relatives, the chimpanzee (Pan troglodytes), have been widely described in various contexts, showing a high level of dexterity both in zoo and in natural conditions. In contrast, the study of bonobos' manipulative abilities has almost exclusively been carried out in experimental contexts related to tool use. The objective of the present study is to describe the richness of the manipulative repertoire of zoo‐housed bonobos, in a spontaneous feeding context including various physical substrates to gain a larger insight into our evolutionary past. Our study describes a great variety of grasping postures and grip associations in bonobos, close to the range of manipulative repertoire in chimpanzees, confirming that the two species are not markedly different in terms of cognitive and morphological constraints associated with food manipulation. We also observed differences in manipulative behaviors between juveniles and adults, indicating a greater diversity in grip associations and grasping postures used in isolation with age, and a sex‐biased use of tools with females using tools more often than males. These results are consistent with the previous results in the Pan genus and reinforce the hypothesis that the evolutionary mechanisms underlying the flexibility of manipulative behaviors are shared by both species and that these ecological strategies would have already evolved in their common ancestor.
Tau‐induced deficits in nonsense‐mediated mRNA decay contribute to neurodegeneration
Authors: Zuniga Gabrielle , Levy Simon , Ramirez Paulino , De Mange Jasmine , Gonzalez Elias , Gamez Maria , Frost Bess
Published: April 2022

Introduction

While brains of patients with Alzheimer's disease and related tauopathies have evidence of altered RNA processing, we lack a mechanistic understanding of how altered RNA processing arises in these disorders and if such changes are causally linked to neurodegeneration.

Methods

Using Drosophila melanogaster models of tauopathy, we find that overall activity of nonsense‐mediated mRNA decay (NMD), a key RNA quality‐control mechanism, is reduced. Genetic manipulation of NMD machinery significantly modifies tau‐induced neurotoxicity, suggesting that deficits in NMD are causally linked to neurodegeneration. Mechanistically, we find that deficits in NMD are a consequence of aberrant RNA export and RNA accumulation within nuclear envelope invaginations in tauopathy. We identify a pharmacological activator of NMD that suppresses neurodegeneration in tau transgenic Drosophila, indicating that tau‐induced deficits in RNA quality control are druggable.

Discussion

Our studies suggest that NMD activators should be explored for their potential therapeutic value to patients with tauopathies.
A 3D‐printable device allowing fast and reproducible longitudinal preparation of mouse intestines
Authors: DeLucia Beckey , Samorezov Sergey , Zangara Megan T. , Markley Rachel L. , Osborn Lucas J. , Schultz Karlee B. , McDonald Christine , Claesen Jan
Published: April 2022

Accurate and reproducible analysis of murine small and large intestinal tissue is key for preclinical models involving intestinal pathology. Currently, there is no easily accessible, standardized method that allows researchers of different skill levels to consistently dissect intestines in a time‐efficient manner. Here, we describe the design and use of the 3D‐printed “Mouse Intestinal Slicing Tool” (MIST), which can be used to longitudinally dissect murine intestines for further analysis. We benchmarked the MIST against a commonly used procedure involving scissors to make a longitudinal cut along the intestines. Use of the MIST halved the time per mouse to prepare the intestines and outperformed alternative methods in smoothness of the cutting edge and overall reproducibility. By sharing the plans for printing the MIST, we hope to contribute a uniformly applicable method for saving time and increasing consistency in studies of the mouse gastrointestinal tract.
A Noncovalent Photoswitch for Photochemical Regulation of Enzymatic Activity
Authors: Chai Jingshan , Zhao Yu , Xu Lina , Li Qiushi , Hu Xin‐Yue , Guo Dong‐Sheng , Liu Yang
Published: April 2022

Photochemical regulation provides a promising approach for controlling enzyme activity on demand owing to its high spatiotemporal resolution. However, reversible regulation of the enzyme activity by light usually requires genetic mutations and covalent modifications of the target enzymes, which may lead to irreversible changes in the enzyme structure and subsequent loss of the enzymatic activity. Herein, we have developed a novel strategy based on a polymeric inhibitor‐encapsulated enzyme, which noncovalently anchors the azobenzene‐modified inhibitors to the enzyme active site, thereby achieving reversible control of the activity of native enzymes using light. As neither genetic mutation nor chemical modification of enzymes is required for this method, negligible loss of the enzymatic activity was observed for the encapsulated enzymes compared to their native counterparts. Thus, this approach has demonstrated a promising strategy for achieving reversible regulation of the activity of native enzymes.
A Ruthenium(II) Polypyridyl Complex Disrupts Actin Cytoskeleton Assembly and Blocks Cytokinesis
Authors: Gill Martin R. , Jarman Paul J. , Hearnden Vanessa , Fairbanks Simon D , Bassetto Marcella , Maib Hannes , Palmer John , Ayscough Kathryn R. , Thomas Jim A. , Smythe Carl
Published: April 2022

The dinuclear RuII complex [(Ru(phen)2)2(tpphz)]4+ (phen=1,10‐phenanthroline, tpphz=tetrapyridophenazine) “RuRuPhen” blocks the transformation of G‐actin monomers to F‐actin filaments with no disassembly of pre‐formed F‐actin. Molecular docking studies indicate multiple RuRuPhen molecules bind to the surface of G‐actin but not the binding pockets of established actin polymerisation inhibitors. In cells, addition of RuRuPhen causes rapid disruption to actin stress fibre organisation, compromising actomyosin contractility and cell motility; due to this effect RuRuPhen interferes with late‐stage cytokinesis. Immunofluorescent microscopy reveals that RuRuPhen causes cytokinetic abscission failure by interfering with endosomal sorting complexes required for transport (ESCRT) complex recruitment.
Strain of Supramolecular Interactions in Single‐Stacking Junctions
Authors: Li Ruihao , Zhou Yu , Ge Wenhui , Zheng Jueting , Zhu Yixuan , Bai Jie , Li Xiaohui , Lin Luchun , Duan Huicong , Shi Jia , Yang Yang , Liu Junyang , Liu Zitong , Hong Wenjing
Published: April 2022

Supramolecular electronics provide opportunities to integrate molecular building blocks into electronic circuits, and investigations of the mechanical properties of the non‐covalent interactions are necessary to understand the role of the assembly configuration in the electronic coupling among different assembly blocks. However, the mechanical characterization of supramolecular interactions remains experimentally challenging. We investigated the strain distribution of the supramolecular interactions through a series of single‐stacking junctions. The alpha values exhibit a clear odd‐even effect versus the numbers of thiophene rings. The theoretical calculations demonstrated that a larger rotational barrier of the single‐stacking junctions with an even number of thiophene rings leads to limited torsional freedom and thus a smaller strain distribution. These results provide new insights into the control of supramolecular interactions by the design of the basic molecular building blocks.
Total Synthesis of (+)‐Cochlearol B by an Approach Based on a Catellani Reaction and Visible‐Light‐Enabled [2+2] Cycloaddition**
Authors: Richardson Alistair D. , Vogel Trenton R. , Traficante Emily F. , Glover Kason J. , Schindler Corinna S.
Published: April 2022

A 14‐step synthesis of (+)‐cochlearol B is reported. This renoprotective meroterpenoid features a unique core structure containing a densely substituted cyclobutane ring with three stereocenters. Our strategy employed an organocatalytic Kabbe condensation in route to the key chromenyl triflate. A subsequent Catellani reaction incorporated the remaining carbon atoms featured in the skeleton of cochlearol B. An ensuing visible‐light‐mediated [2+2] photocycloaddition closed the cyclobutane and formed the central bicyclo[3.2.0]heptane core. Notably, careful design and tuning of the Catellani and photocycloaddition reactions proved crucial in overcoming undesired reactivity, including cyclopropanation reactions and [4+2] cycloadditions.
Diastereoselective Transfer of Tri(di)fluoroacetylsilanes‐Derived Carbenes to Alkenes
Authors: Zhang Yizhi , Zhou Gang , Gong Xingxing , Guo Zhuanzhuan , Qi Xiaotian , Shen Xiao
Published: April 2022

Stereoselective cyclopropanation reaction of alkenes is usually achieved by metal complexes via singlet‐metal‐carbene intermediates. However, previous transition‐metal‐catalyzed cyclopropanation of alkenes with acylsilanes afforded low diastereoselectivity. Herein, we report the first visible‐light‐induced transition‐metal‐free cyclopropanation reaction of terminal alkenes with trifluoroacetylsilanes and difluoroacetylsilanes. Both aromatic and aliphatic alkenes as well as electron‐deficient alkenes are suitable substrates for the highlycis‐selective [2+1] cyclization reaction. A combination of experimental and computational studies identified triplet carbenes as being key intermediates in this transformation. The gram scale reaction and late‐stage functionalization demonstrated the synthetic potential of this strategy.
Activation of Main‐Group Antimony Atomic Sites for Oxygen Reduction Catalysis
Authors: Gu Yu , Xi Baojuan J. , Zhang Hua , Ma Yuchen C. , Xiong Shenglin L.
Published: April 2022

The catalytic activity of main‐group metal is hard to promote because of the intrinsic lack of host d orbitals available to be combined. Herein, under the guidance of theoretical predictions, we find atom‐dispersed antimony sites (Sb−N4 moieties) can be activated to achieve high oxygen reduction reaction (ORR) activity using a functional group regulation strategy. Correspondingly, we manage to synthesize a main‐group Sb single‐atom catalysts (SACs) that comprises Sb−N4 active moieties functionalized by epoxy groups in the second microenvironment and incorporated in N‐doped graphene (Sb1/NG(O)). The electron‐rich epoxy group can adjust the electronic structure of Sb−N4 active moieties, thereby optimizing the adsorption of the intermediate. The Sb SACs are comparable to industrial Pt/C under alkaline conditions. This discovery provides new opportunities to manipulate and improve the catalytic activity of main‐group‐element electrocatalysts.
Sequential Allylic Alcohol Formation by a Multifunctional Cytochrome P450 Monooxygenase with Rare Redox Partners
Authors: Kim Hak Joong , Ishida Keishi , Ishida‐Ito Mie , Hertweck Christian
Published: April 2022

Caryoynencin is a toxic and antifungal fatty acid derivative produced by a number of plant‐pathogenic and insect‐protective bacteria (Trinickia caryophylli and Burkholderia spp.). In addition to the reactive tetrayne unit, the presence of an allylic alcohol moiety is critical for antimicrobial activities. By a combination of mutational analyses, heterologous expression and in vitro reconstitution experiments we show that the cytochrome P450 monooxygenase CayG catalyzes the complex transformation of a saturated carbon backbone into an allylic alcohol. Unexpectedly, CayG employs a ferritin‐like protein (CayK) or a rubredoxin (CayL) component for electron transport. A desaturation‐hydroxylation sequence was deduced from a time‐course study and in vitro biotransformations with pathway intermediates, substrate analogues, protegencin congeners from Pseudomonas protegens Pf‐5, and synthetic derivatives. This unusual multifunctional oxygenase may inspire future biocatalytic applications.
Herstellung von benzylischen Natrium‐Metallorganylen im kontinuierlichen Durchfluss
Authors: Harenberg Johannes H. , Reddy Annapureddy Rajasekar , Karaghiosoff Konstantin , Knochel Paul
Published: April 2022

Wir beschreiben eine laterale Natriierung von Alkali(hetero)arenen mittels bedarfsgerecht generiertem, in Hexan löslichem (2‐Ethylhexyl)natrium (1) in Gegenwart von TMEDA. (2‐Ethylhexyl)natrium (1) wird mittels eines Natrium‐Festbettreaktors hergestellt und für Metallierungen bei Umgebungstemperatur sowohl im Kolben als auch im kontinuierlichem Durchfluss genutzt. Die entstehenden benzylischen Natriumspezies werden nachfolgend mit verschiedenen Elektrophilen, unter anderem Carbonylverbindungen, Epoxiden, Oxetan, Allyl/Benzylchloriden, Alkylhalogenen und ‐tosylaten abgefangen. Wurtz‐Typ‐Kopplungen mit sekundären Alkylhalogenen und Tosylaten laufen unter kompletter Inversion der Stereochemie ab. Des Weiteren wird die Nützlichkeit dieser lateralen Natriierung durch die Synthese pharmazeutisch relevanter Verbindungen demonstriert. So wird Fingolimod durch die zweifache Anwendung der lateralen Natriierung ausgehend von p‐Xylol hergestellt. Zusätzlich ist 7‐fach Isotopen angereichertes Salmeterol‐d7 und Fenpiprane, sowie Ausgangsmaterialien zu super linearen Alkylbenzyl (SLAB) Tensiden hergestellt worden.
Two‐Dimensional Photosensitizer Nanosheets via Low‐Energy Electron Beam Induced Cross‐Linking of Self‐Assembled RuII Polypyridine Monolayers
Authors: Küllmer Maria , Herrmann‐Westendorf Felix , Endres Patrick , Götz Stefan , Reza Rasouli Hamid , Najafidehaghani Emad , Neumann Christof , Gläßner Rebecka , Kaiser David , Weimann Thomas , Winter Andreas , Schubert Ulrich S. , Dietzek‐Ivanšić Benjamin , Turchanin Andrey
Published: April 2022

Artificial photosynthesis for hydrogen production is an important element in the search for green energy sources. The incorporation of photoactive units into mechanically stable 2D materials paves the way toward the realization of ultrathin membranes as mimics for leaves. Here we present and compare two concepts to introduce a photoactive RuII polypyridine complex into ≈1 nm thick carbon nanomembranes (CNMs) generated by low‐energy electron irradiation induced cross‐linking of aromatic self‐assembled monolayers. The photoactive units are either directly incorporated into the CNM scaffold or covalently grafted to its surface. We characterize RuII CNMs using X‐ray photoelectron, surface‐enhanced Raman, photothermal deflection spectroscopy, atomic force, scanning electron microscopy, and study their photoactivity in graphene field‐effect devices. Therewith, we explore the applicability of low‐energy electron irradiation of metal complexes for photosensitizer nanosheet formation.
Alteration of the Catalytic Reaction Trajectory of a Vicinal Oxygen Chelate Enzyme by Directed Evolution
Authors: Wang Yi Shuang , Zheng Wan , Jiang Nan , Jin Yun Xia , Meng Zi Kang , Sun Meng Xin , Zong Yu Liang , Xu Tong , Zhu Jiapeng , Tan Ren Xiang
Published: April 2022

The vicinal oxygen chelate (VOC) metalloenzyme superfamily catalyzes a highly diverse set of reactions with the mechanism characterized by the bidentate coordination of vicinal oxygen atoms to metal ion centers, but there remains a lack of a platform to steer the reaction trajectories, especially for o‐quinone metabolizing pathways. Herein, we present the directed‐evolution‐enabled bifunctional turnover of ChaP, which is a homotetramer and represents an unprecedented VOC enzyme class. Unlike the ChaP catalysis of extradiol‐like o‐quinone cleavage and concomitant α‐keto acid decarboxylation, a group of ChaP variants (CVs) catalyze intradiol‐like o‐quinone deconstruction and CO2 liberation from the resulting o‐hydroxybenzoic acid scaffolds with high regioselectivity. Enzyme crystal structures, labeling experiments and computational simulations corroborated that the D49L mutation allows the metal ion to change its coordination with the tyrosine phenoxy atoms in different monomers, thereby altering the reaction trajectory with the regiospecificity further improved by the follow‐up replacement of the Y92 residue with any of alanine, glycine, threonine, and serine. The study highlights the unpredicted catalytic versatility and enzymatic plasticity of VOC enzymes with biotechnological significance.
Trapping X‐ray Radiation Damage from Homolytic Se−C Bond Cleavage in BnSeSeBn Crystals (Bn=benzyl, CH2C6H5)
Authors: Schürmann Christian J. , Teuteberg Thorsten L. , Stückl A. Claudia , Ruth Paul Niklas , Hecker Fabian , Herbst‐Irmer Regine , Mata Ricardo A. , Stalke Dietmar
Published: April 2022

Irradiation of dibenzyl diselenide BnSeSeBn with X‐ray or UV‐light cleaves the Se−C and the Se−Se bonds, inducing stable and metastable radical states. They are inevitably important to all natural and life sciences. Structural changes due to X‐ray‐induced Se−C bond‐cleavage could be pin‐pointed in various high‐resolution X‐ray diffraction experiments for the first time. Extended DFT methods were applied to characterize the solid‐state structure and support the refinement of the observed residuals as contributions from the BnSeSe⋅ radical species. The X‐ray or UV‐irradiated crystalline samples of BnSeSeBn were characterized by solid‐state EPR. This paper provides insight that in the course of X‐ray structure analysis of selenium compounds not only organo‐selenide radicals like RSe⋅ may occur, but also organo diselenide BnSeSe⋅ radicals and organic radicals R⋅ are generated, particularly important to know in structural biology.
Dynamic Interconversions of Single Molecules Probed by Recognition Tunneling at Cucurbit[7]uril‐Functionalized Supramolecular Junctions
Authors: Xiao Bohuai , He Suhang , Sun Mingjun , Zhou Jianghao , Wang Zhiye , Li Yunchuan , Liu Simin , Nau Werner M. , Chang Shuai
Published: April 2022

We introduce a versatile recognition tunneling technique using doubly cucurbit[7]uril‐functionalized electrodes to form supramolecular junctions that capture analytes dynamically by host–guest complexation. This results in characteristic changes in their single‐molecule conductance. For structurally related drug molecules (camptothecin, sanguinarine, chelerythrine, and berberine) and mixtures thereof, we observed distinct current switching signals related to their intrinsic conductance properties as well as pH‐dependent effects which can be traced back to their different states (protonated versus neutral). The conductance variation of a single molecule with pH shows a sigmoidal distribution, allowing us to extract a pKa value for reversible protonation, which is consistent with the reported macroscopic results. The new electronic method allows the characterization of unmodified drug molecules and showcases the transfer of dynamic supramolecular chemistry principles to single molecules.
The effects of acetamiprid multigeneration stress on metabolism and physiology of Aphis glycines Matsumura (Hemiptera: Aphididae)
Authors: Zhang Aonan , Xu Ling , Liu Ziqi , Zhang Jiabo , Han Lanlan , Zhao Kuijun
Published: April 2022

Aphis glycines Matsumura (Hemiptera: Aphididae) is a major soybean pest that often poses a serious threat to soybean production. In this study, we checked the effects of acetamiprid on redox, energy metabolism, and hormone expression in A. glycines. The LC50 and LC30 of acetamiprid were used to treat the fourth instar nymphs in each generation from F0 to F4 to measure the activity of peroxidase, pyruvate kinase, and trehalase using a microassays approach. The peroxidase activity was significantly higher than control when treated with the LC30 of acetamiprid in F2−F5 generations. The activity of pyruvate kinase was significantly higher, while trehalase activity was substantially lower than control in each generation. Besides, we monitored molting and juvenile hormone expression in soybean aphids using enzyme‐linked immunosorbent assay. The juvenile hormone titer of third instar nymphs was significantly higher in the treatment group (F1, F2, F4, and F5), while no effects were noted in the F3 generation. Taken together, the activity of peroxidase and pyruvate kinase in soybean aphid first increased to the peak and then decreased, while the trehalase activity continuously decreased in all generations following exposure to acetamiprid. The juvenile hormone titer was significantly higher, while the molting hormone titer was significantly lower in LC50‐treated aphids than in control. Moreover, the LC30 of acetamiprid increased the molting hormone expression in soybean aphids. These findings indicated a baseline for the effective use of acetamiprid in controlling soybean aphids.
Chiral Cyclopropenimine‐catalyzed Asymmetric Michael Addition of Bulky Glycine Imine to α,β‐Unsaturated Isoxazoles
Authors: Bai Yu‐Jun , Cheng Mei‐Ling , Zheng Xiao‐Hui , Zhang Sheng‐Yong , Wang Ping‐An
Published: April 2022

A highly efficient asymmetric Michael addition of bulky glycine imine to α,β‐unsaturated isoxazoles has been achieved by using 5 mol% of chiral cyclopropenimine as a chiral organo‐superbase catalyst under mild conditions. Michael adducts were obtained in excellent yields (up to 97%) and stereoselectivities (up to >99 : 1 dr and 98% ee). A significant solvent effect was found in these chiral organosuperbase catalyzed asymmetric Michael reactions. Gram‐scale preparation of Michael adducts and their transformations are realized to provide corresponding products without loss of stereoselectivities. The configurations of Michael adduct was determined by single‐crystal X‐ray diffraction analysis.
Cannabidiol impairs neural tube closure in mouse whole embryo culture
Authors: Gheasuddin Yosuf , Galea Gabriel L.
Published: April 2022

Background

Cannabidiol (CBD) is a nonpsychoactive constituent of cannabis widely available as a dietary supplement. Previous reports that it impairs the retinoid, sonic hedgehog, and folate metabolism pathways raise concern that it may impair closure of the embryonic neural tube (NT), producing NT defects including spina bifida and exencephaly.

Methods

We undertook teratogenicity testing of CBD in mouse whole embryo culture.

Results

At concentrations that do not diminish embryo viability, growth, or axial rotation, CBD dose‐dependently impairs cranial NT closure, increasing the proportion of embryos that develop exencephaly. It concomitantly diminishes closure of the spinal NT, the posterior neuropore (PNP), producing longer neuropores at the end of culture which is a hallmark of spina bifida risk. Exposure to CBD does not disrupt the formation of long F‐actin cables in surface ectoderm cells flanking the PNP or folding of the neuroepithelium at predictable hinge points. At the cellular level, CBD exposure does not alter proliferation or apoptosis of the spinal neuroepithelium.

Discussion

Thus, CBD acts selectively as a neuroteratogen predisposing to spina bifida and exencephaly in mouse whole embryo culture at exposure levels not associated with overt toxicity. Large‐scale testing of CBD's effects on NT closure, particularly in at‐risk groups, is warranted to inform its marketing to women of childbearing age.
Sustainable development, ESG performance and company market value: Mediating effect of financial performance
Authors: Zhou Guangyou , Liu Lian , Luo Sumei
Published: April 2022

At present, more and more attention is paid to the sustainable development of enterprises. In particular, in the context of frequent financial crises and COVID‐19 pandemic, how the performance of listed companies' environmental, social, and governance (ESG) affects the company's market value has attracted widespread attention. Different from existing studies, this paper takes financial performance as a mediating variable and constructs linear regression model and mediating effect model based on analyzing the relationship between ESG performance, financial performance, and company market value and their influencing mechanism. The ESG rating data of Chinese listed companies newly developed by SynTao Green Finance from 2014 to 2019 were selected for empirical test. The results show that the improvement of ESG performance of listed companies can improve the market value of the company, and the financial performance of the company presents an obvious mediating effect. At the same time, operational capacity is an important mediating way for ESG performance to affect the company's market value. Further research shows that ESG performance of state‐owned listed companies exerts a stronger mediating effect on corporate operating capacity. Finally, this paper provides relevant suggestions for regulators, listed companies, and investors.
Planning a robotic competition
Authors: Chatzis Dimitris , Papasalouros Andreas , Kavallieratou Ergina
Published: April 2022

Education changes, and pupils and students require a more active role. Educational competitions could be an answer. This paper highlights the key points as these were revealed through setting up an event of an educational robotic competition from zero. It, also, presents statistics collected in different periods: before the competition, directly after it, and finally at a notable time after the competition (about 6 months). To collect the data, the completion of four different questionnaires, for every annual event, was asked separately, by the participants and the organizers. The paper provides empirical insights on setting up an educational competition. It also outlines the characteristics of the students taking part and underlines the results that the contents have on them. It suggests that teamwork and collaboration within the team is a prerequisite for a competition to have an impact on the educational process. Furthermore, robotic competitions raise the interest of students in robotics, programming, and STEM, while they develop social skills and create bonds between the participants. Moreover, it is a useful tool for educators.
Do honesty‐nudges really work? A large‐scale field experiment in an insurance context
Authors: Martuza Jareef Bin , Skard Siv Rosendahl , Løvlie Lavrans , Thorbjørnsen Helge
Published: April 2022

Businesses want their customers to self‐report information honestly. One increasingly popular way to stimulate desired behavior is by using nudge interventions. But can customers be nudged to self‐report information more honestly? This is currently a debate in the literature, where empirical results are inconclusive. Building on related literature on nudges, we add to this debate with a controlled field experiment (N = 5704). We used data from actual customers making real decisions when they file claims online to a large Nordic insurance provider. To the best of our knowledge, this is the first study to investigate the effects of honesty‐nudges on self‐reported information when filing insurance claims using a controlled field experiment. We designed and tested three honesty‐nudges on insurance customers: (1) signing‐at‐the‐beginning, (2) a descriptive social norm message, and (3) a solidarity message. Across five outcome measures, we found that the honesty‐nudges, standalone or in any possible combination, do not have significant effects in reducing indicators of insurance claims fraud. But interestingly, customers in all treatment groups used significantly more characters to describe losses than customers in the control group. Also, in post hoc analyses, we found signs that the direction of nudge effects varies across customers' age and customer loyalty.
Synthesis of VS2/NiS Nanocomposites by In Situ Growing NiS Clusters on VS2 Ultrathin Nanoplates for High Performance Supercapacitors
Authors: Zhang Qi , Chen Xin , Cheng Siyu , Li Runfa , E Yi , Jiang Meng
Published: April 2022

Novel transition metal sulfide composite VS2/NiS nanomaterials are synthesized through a two‐step route, where VS2 was synthesized by colloidal chemical method, and NiS was in situ grown between the ultrathin and defective VS2 through a hydrothermal method. The composites showed VS2 nanoplates wrapped with a NiS clusters structure. Under the 1 : 7 optimal composite ratio, the VS2/NiS electrode exhibits a specific capacitance of 2416.5 F/g at 1 A/g, the specific capacitance stays at 930.2 F/g when the current density increases to 20 A/g. The asymmetric supercapacitor assembled with VS2/NiS‐1 : 7 and activated carbon electrodes also exhibits an ultrahigh energy density of 69.58 Wh/kg at a power density of 874.9 W/kg and showed good cycling performance with 74.9 % capacitance retention after 3000 cycles. This work not only demonstrates the excellent performance of the VS2/NiS composites in supercapacitors, but also provided a new compound strategy for transition metal sulfides.
MIL‐47(V) Derived V2O5@Carbon Core‐Shell Microcuboids with Oxygen Vacancies as Advanced Conversion Cathodes for High‐Performance Zinc‐Ion Batteries
Authors: He Tianqi , Li Jinhang , Luo Zhengzhi , Zhang Yuqiang , Zhao Yingying , Zhang Xitian , Chen Yujin
Published: April 2022

Vanadium pentoxide (V2O5) has been considered one of the most promising cathodes for zinc‐ion batteries (ZIBs) due to its outstanding theoretical capacity (589 mAh g−1). However, it remains great challenge to achieve the high capacity, limited to the poor electronic conductivity and sluggish ionic diffusion kinetics of V2O5. Herein, a controllable strategy is proposed to synthesize V2O5@carbon core‐shell microcuboids with oxygen vacancies (V2O5‐x@CCSMs) derived from MIL‐47(V) used for cathodes of ZIBs. The obtained V2O5‐x@CCSMs cathode delivers high capacities of 485.4 and 392.1 mAh g−1 at 0.1 and 2.0 A g−1, respectively. The superior electrochemical performances originate from the nano‐sized particles of V2O5, oxygen vacancies and carbon shell. Further, ex‐situ XRD indicates V2O5 undergoes a shrinking core model conversion reaction at initial cycling to a new phase of Zn3V2O7(OH)2 ⋅ 2H2O, which is an ideal host for Zn2+. Our work offers an innovative strategy to develop high‐capacity cathode in ZIBs.
Diverse Supports for Immobilization of Catalysts in Continuous Flow Reactors
Authors: Lin Geyu , Qiu Huibin
Published: April 2022

The rapid development of continuous flow processes is driving innovations in various chemical syntheses and industrial productions. Immobilizing catalysts in flow reactors allows transformations with high‐efficiency and excludes the subsequent separation procedures. This concept outlines the approaches to incorporate catalysts within flow reactors, with particular focus on the application of additional supports including inorganic materials like silica, zeolite and reduced graphene oxide, polymeric materials like polymer packings, monoliths, cross‐linked gels and polymer brushes, and other materials for specific conditions like transparent glass fibers and glass beads. Furthermore, advanced methods to develop ordered micro‐/nanoarrays from internal walls of flow channels for immobilization of catalysts as well as application of innovative vortex fluidic devices are discussed to inspire new designs of supports for novel fluidic reactors with broad applications.
2,3‐Disubstituted Fluorene Scaffold for Efficient Green Phosphorescent Organic Light‐Emitting Diodes
Authors: Wei Jia‐Jia , Yang Yong‐Jian , Liu Xiang‐Yang , Li Runlai , Li Shu‐an
Published: April 2022

Fluorene is a classic three‐membered polycyclic aromatic hydrocarbon, and it has been widely used in optoelectronic devices. Here we explore a simple and efficient strategy for the derivatization at the 2‐ and 3‐ positions in fluorene unit. By introducing different types of substituents, we design two pairs of 2,3‐disubstituted fluorene isomers and use them as host materials for phosphorescent organic light‐emitting diodes (PHOLEDs). The green PHOLEDs hosted by these fluorene derivatives realize high external quantum efficiencies (EQE) over 20 % with low efficiency roll‐off. Particularly, the devices hosted by 2TRz3TPA and 2TPA3TRz achieve nearly 24 % EQE and 104 lm W−1power efficiency. These results clearly demonstrate that the 2,3‐disubstituted fluorene platforms are potentially useful for constructing host materials.
An Orthogonal Dynamic Covalent Chemistry Tool for Ring‐Opening Polymerization of Cyclic Oligochalcogenides on Detachable Helical Peptide Templates
Authors: Laurent Quentin , Sakai Naomi , Matile Stefan
Published: April 2022

A model system is introduced as a general tool to elaborate on orthogonal templation of dynamic covalent ring‐opening polymerization (ODC‐TROP). The tool consists of 310 helical peptides as unprecedented templates and semicarbazones as orthogonal dynamic covalent linkers. With difficult‐to‐control 1,2‐dithiolanes, ODC‐TROP on the level of short model oligomers occurs with high templation efficiency, increasing and diminishing upon helix stabilization and denaturation, respectively. Further, an anti‐templated conjugate with mispositioned monomers gave reduced templation upon helix twisting. Even with the “unpolymerizable” 1,2‐diselenolanes, initial studies already afford mild templation efficiency. These proof‐of‐principle results promise that the here introduced tool, recyclable and enabling late‐stage side chain modification, will be useful to realize ODC‐TROP of intractable or unknown cyclic dynamic covalent monomers for dynamer materials as well as cellular uptake and signaling applications.
Remarkable enantioselectivity enhancement of the extractors with nonaxial chirality in liquid–liquid extraction of underivatized amino acids by introducing t‐butyl group
Authors: Jin Yingji , Chen Qian , Zhang Yan , Lee Yejeong , Kang Dayoung , Kim Youngmee , Kim Sung‐Jin , Su Zhishan , Huang Haofei , Kim Kwan Mook
Published: April 2022

A class of carbonyl extractors, (R)‐3, (R)‐4, and (R)‐5, with nonaxial chirality containing asymmetric carbons has been synthesized and studied for their efficiencies in enantioselective liquid–liquid extraction for underivatized amino acids. The bulky t‐butyl ketone extractors, (R)‐4 and (R)‐5, showed the stereoselectivities ranging 5.4–9.4 of l/d ratio much better than those of the aldehyde extractor, (R)‐3, ranging 2.4–5.2. The imine formation rates and yields of the t‐butyl ketones were not significantly affected by their bulkiness and even in the absence of resonance‐assisted hydrogen bond. This work confirms that a bulky t‐butyl ketone can be a good choice in the development of an extractor not only with axial chirality but also with nonaxial chirality for the enantioselective extraction of unprotected amino acids.