bluuebunny/crossref_metadata_2025 huggingface dataset:
Memristive Devices for New Computing Paradigms
Authors: Im In Hyuk , Kim Seung Ju , Jang Ho Won
Published: August 2020

In complementary metal–oxide–semiconductor (CMOS)‐based von Neumann architectures, the intrinsic power and speed inefficiencies are worsened by the drastic increase in information with big data. With the potential to store numerous values in I–V pinched hysteresis, memristors (memory resistors) have emerged as alternatives to existing CMOS‐based computing systems. Herein, four types of memristive devices, namely, resistive switching, phase‐change, spintronics, and ferroelectric tunnel junction memristors, are explored. The application of these devices to a crossbar array (CBA), which is a novel concept of integrated architecture, is a step toward the realization of ultradense electronics. Exploiting the fascinating capabilities of memristive devices, computing systems can be developed with novel computing paradigms, in which large amounts of data can be stored and processed within CBAs. Looking further ahead, the ways in which memristors could be incorporated in neuromorphic computing systems along with various artificial intelligence algorithms are established. Finally, perspectives and challenges that memristor technology should address to provide excellent alternatives to existing computing systems are discussed. The infinite potential of memristors is the key to unlock new computing paradigms, which pave the way for next‐generation computing systems.
Microcephalic osteodysplastic primordial dwarfism type II and pachygyria: Morphometric analysis in a 2‐year‐old girl
Authors: Rossi‐Espagnet Maria C. , Dentici Maria L. , Pasquini Luca , Carducci Chiara , Lucignani Martina , Longo Daniela , Agolini Emanuele , Novelli Antonio , Gonfiantini Michaela V. , Digilio Maria C. , Napolitano Antonio , Bartuli Andrea
Published: August 2020

Microcephalic osteodysplastic primordial dwarfism (MOPD) type II is a rare disorder characterized by skeletal dysplasia, severe proportionate short stature, insulin resistance and cerebrovascular abnormalities including cerebral aneurysms and moyamoya disease. MOPD type II is caused by mutations in the pericentrin (PCNT) gene, which encodes a protein involved in centrosomes function. We report a 2 year old girl affected by MOPD type II caused by two compound heterozygous loss‐of‐function variants in PCNT gene, of which one is a novel variant (c.5304delT; p.Gly1769AlafsTer34). The patient presented atypical brain magnetic resonance imaging (MRI) findings consistent with pachygyria. This was confirmed by morphometric analysis of cortical thickness (CT) and gyrification index by comparing MRI data of the patient with a group of eight age‐matched healthy controls. The statistical analysis revealed a significant and diffuse increase of CT with an anterior‐predominant pattern and diffuse reduced gyrification (p < .05). These findings provide new evidences to the emergent concept that malformations of cortical development are complex disorders and that new genetic findings contribute to the fading of classification borders.
Early life stress and HPA axis function independently predict adult depressive symptoms in metropolitan Cebu, Philippines
Authors: Kim Andrew Wooyoung , Adam Emma K. , Bechayda Sonny A. , Kuzawa Christopher W.
Published: August 2020

Objectives

Alterations in adult hypothalamic–pituitary–adrenal (HPA) axis activity have increasingly been linked with early life stress and adult depression, but a limited number of studies have used longitudinal data to explore HPA axis dysregulation as an underlying mechanism driving the long‐term depressive impacts of early stressors. Here we address potential long‐term impacts of early life, family‐based stress on depressive symptoms among young adults in a longitudinal birth cohort study begun in 1983 in the Philippines.

Materials and methods

We relate a composite measure of family‐based stressors experienced between birth and adolescence to circadian dynamics in adult salivary cortisol and depressive risk measured at 21–22 years of age. Multiple regression analyses were conducted to examine the relationship between early life stress levels and risk of adult depressive symptoms, as well as the role of adult diurnal cortisol activity in this relationship.

Results

Greater levels of early life familial stress predicted more severe depressive symptomatology at age 21–22 in a dose–response fashion (p < .0001) independent of adult diurnal cortisol patterns. Flatter diurnal cortisol slopes are directly associated with higher adult depressive symptoms, an effect mostly driven by evening cortisol levels (p = .004). When considering the cumulative effects of early life stress measures, however, exposure to more of these stressors during development is associated with even higher depressive symptoms.

Discussion

The long‐term depressive effects of early life familial stress extend to this large sample of Cebuano young adults, and early life stress and HPA axis function may shape adult depressive symptoms through independent pathways in this sample. Our findings provide further evidence that HPA axis activity is shaped by early life conditions and is associated with depressive symptoms.
SERS‐Active MIL‐100(Fe) Sensory Array for Ultrasensitive and Multiplex Detection of VOCs
Authors: Fu Jing‐Hao , Zhong Zhen , Xie Dan , Guo Yan‐Jun , Kong De‐Xuan , Zhao Zhong‐Xing , Zhao Zhen‐Xia , Li Min
Published: August 2020

The application of metal–organic frameworks (MOFs) as SERS‐active platforms in multiplex volatile organic compounds (VOCs) detection is still unexplored. Herein, we demonstrate that MIL‐100 (Fe) serves as an ideal SERS substrate for the detection of VOCs. The limit of detection (LOD) of MIL‐100(Fe) for toluene sensing can reach 2.5 ppm, and can be even further decreased to 0.48 ppb level when “hot spots” in between Au nanoparticles are employed onto MIL‐100 (Fe) substrate, resulting in an enhancement factor of 1010. Additionally, we show that MIL‐100(Fe) substrate has a unique “sensor array” property allowing multiplex VOCs detection, with great modifiability and expandability by doping with foreign metal elements. Finally, the MIL‐100(Fe) platform is utilized to simultaneously detect the different gaseous indicators of lung cancer with a ppm detection limit, demonstrating its high potential for early diagnosis of lung cancer in vivo.
An Acid‐Activatable Fluorescence Probe for Imaging Osteocytic Bone Resorption Activity in Deep Bone Cavities
Authors: Hashimoto Ryu , Minoshima Masafumi , Kikuta Junichi , Yari Shinya , Bull Steven D. , Ishii Masaru , Kikuchi Kazuya
Published: August 2020

A rationally designed pH‐activatable fluorescent probe (pHocas‐RIS) has been used to measure localised pH levels in osteocytic lacunae in bone tissue. Conjugation of the moderate bone‐binding drug risedronate to a pH‐activatable BODIPY fluorophore enables the probe to penetrate osteocytic lacunae cavities that are embedded deep within the bone matrix. After injection of pHocas‐RIS, any osteocytic lacunae caused by bone‐resorbing osteocytes cause the probe to fluoresce in vivo, thus allowing imaging by intravital two‐photon excitation microscopy. This pH responsive probe enabled the visualization of the bone mineralizing activities of acid producing osteocytes in real time, thus allowing the study of their central role in remodeling the bone‐matrix in healthy and disease states.
An Integrated Microfluidic Probe for Mass Spectrometry Imaging of Biological Samples**
Authors: Li Xiangtang , Yin Ruichuan , Hu Hang , Li Yingju , Sun Xiaofei , Dey Sudhansu K. , Laskin Julia
Published: August 2020

Ambient ionization based on liquid extraction is widely used in mass spectrometry imaging (MSI) of molecules in biological samples. The development of nanospray desorption electrospray ionization (nano‐DESI) has enabled the robust imaging of tissue sections with high spatial resolution. However, the fabrication of the nano‐DESI probe is challenging, which limits its dissemination to the broader scientific community. Herein, we describe the design and performance of an integrated microfluidic probe (iMFP) for nano‐DESI MSI. The glass iMFP, fabricated using photolithography, wet etching, and polishing, shows comparable performance to the capillary‐based nano‐DESI MSI in terms of stability and sensitivity; a spatial resolution of better than 25 μm was obtained in these first proof‐of‐principle experiments. The iMFP is easy to operate and align in front of a mass spectrometer, which will facilitate broader use of liquid‐extraction‐based MSI in biological research, drug discovery, and clinical studies.
Radical‐Cation Cascade to Aryltetralin Cyclic Ether Lignans Under Visible‐Light Photoredox Catalysis
Authors: Xiang Jia‐Chen , Wang Qian , Zhu Jieping
Published: August 2020

The development of concise, sustainable, and cost‐effective synthesis of aryltetralin lignans, bearing either a fused lactone or cyclic ether, is of significant medicinal importance. Reported is that in the presence of Fukuzumi's acridinium salt under blue LED irradiation, functionalized dicinnamyl ether derivatives are converted into aryltetralin cyclic ether lignans with concurrent generation of three stereocenters in good to high yields with up to 20:1 diastereoselectivity. Oxidation of an alkene to the radical cation is key to the success of this formal Diels–Alder reaction of electronically mismatched diene and dienophile. Applying this methodology, six natural products, aglacin B, aglacin C, sulabiroin A, sulabiroin B, gaultherin C, and isoshonanin, are synthesized in only two to three steps from readily available biomass‐derived monolignols. A revised structure is proposed for gaultherin C.
Direct Observation of Defect‐Aided Structural Evolution in a Nickel‐Rich Layered Cathode
Authors: Li Shuang , Yao Zhenpeng , Zheng Jianming , Fu Maosen , Cen Jiajie , Hwang Sooyeon , Jin Huile , Orlov Alexander , Gu Lin , Wang Shun , Chen Zhongwei , Su Dong
Published: August 2020

Ni‐rich LiNi1−x−yMnxCoyO2 (NMC) layered compounds are the dominant cathode for lithium ion batteries. The role of crystallographic defects on structure evolution and performance degradation during electrochemical cycling is not yet fully understood. Here, we investigated the structural evolution of a Ni‐rich NMC cathode in a solid‐state cell by in situ transmission electron microscopy. Antiphase boundary (APB) and twin boundary (TB) separating layered phases played an important role on phase change. Upon Li depletion, the APB extended across the layered structure, while Li/transition metal (TM) ion mixing in the layered phases was detected to induce the rock‐salt phase formation along the coherent TB. According to DFT calculations, Li/TM mixing and phase transition were aided by the low diffusion barriers of TM ions at planar defects. This work reveals the dynamical scenario of secondary phase evolution, helping unveil the origin of performance fading in Ni‐rich NMC.
Single Atoms of Iron on MoS2 Nanosheets for N2 Electroreduction into Ammonia
Authors: Su Hongyang , Chen Lanlan , Chen Yizhen , Si Rui , Wu Yuting , Wu Xiaonan , Geng Zhigang , Zhang Wenhua , Zeng Jie
Published: August 2020

Efforts have been devoted to achieving a highly efficient artificial synthesis of ammonia (NH3). Reported herein is a novel Fe‐MoS2 catalyst with Fe atomically dispersed onto MoS2 nanosheets, imitating natural nitrogenase, to boost N2 electroreduction into NH3 at room temperature. The Fe‐MoS2 nanosheets exhibited a faradic efficiency of 18.8 % with a yield rate of 8.63 μg
 mgcat.−1 h−1 for NH3 at −0.3 V versus the reversible hydrogen electrode. The mechanism study revealed that the electroreduction of N2 was promoted and the competing hydrogen evolution reaction was suppressed by decorating the edge sites of S in MoS2 with the atomically dispersed Fe, resulting in high catalytic performance for the electroreduction of N2 into NH3. This work provides new ideas for the design of catalysts for N2 electroreduction and strengthens the understanding about N2 activation over Mo‐based catalysts.
Hoch regioselektive Addition von allylischen Zinkhalogeniden und verschiedenen Zinkenolaten an [1.1.1]Propellan
Authors: Schwärzer Kuno , Zipse Hendrik , Karaghiosoff Konstantin , Knochel Paul
Published: August 2020

Wir berichten über eine Reihe von hoch regioselektiven Öffnungen von [1.1.1]Propellan mit verschiedenen allylischen Zinkhalogeniden, sowie mit Zinkenolaten von Ketonen, Estern und Nitrilen. Die resultierenden zinkierten Bicyclopentane (BCPs) wurden mit einer Reihe von Elektrophilen abgefangen, einschließlich Carbonsäurechloriden, Sulfonothioaten, Hydroxylaminobenzoaten, Tosylcyanid sowie Aryl‐ und Allylhalogeniden. Dadurch wurden hochfunktionalisierte BCP‐Derivate erzeugt. Die ungewöhnlich hohe Regioselektivität dieser Reaktionen wurde mittels DFT‐Berechnungen rationalisiert. Ein Bioisoster des synthetischen Opioids Pethidin wurde mit Hilfe dieser Methodik in einem Schritt in 95 % Ausbeute hergestellt.
K2Sb(P2O7)F: Cairo Pentagonal Layer with Bifunctional Genes Reveal Optical Performance
Authors: Deng Yalan , Huang Ling , Dong Xuehua , Wang Lei , Ok Kang Min , Zeng Hongmei , Lin Zhien , Zou Guohong
Published: August 2020

Discovering new functional genes, designing perfect crystal structures, and developing high‐performance materials are the goals being pursued by scientists. Herein, the first antimony pyrophosphate, K2Sb(P2O7)F, possessing an optimal layered structure, is reported, where the perfect structural arrangement induces excellent optical properties. K2Sb(P2O7)F not only displays a sharply enhanced birefringence (0.157@546 nm) compared to the existing phosphate optical materials, but also exhibits a strong second‐harmonic generation response (4.0×KDP). Remarkably, a new bifunctional gene, the square‐pyramidal SbO4F group, was discovered, and a unique two‐dimensional arrangement of Cairo pentagonal tiling units was observed in inorganic compounds for the first time.
Self‐Assembled Anion‐Binding Cryptand for the Selective Liquid–Liquid Extraction of Phosphate Anions
Authors: Andrews Rebecca , Begum Sabera , Clemett Christopher J. , Faulkner Robert A. , Ginger Michael L. , Harmer Jane , Molinari Marco , Parkes Gareth M. B. , Qureshi Zuhlqurnain M. H. , Rice Craig R. , Ward Michael D. , Williams Howard M. , Wilson Philippe B.
Published: August 2020

The ligands L1 and L2 form trinuclear self‐assembled complexes with Cu2+ (i.e. [(L1)2Cu3]6+ or [(L2)2Cu3]6+) both of which act as a host to a variety of anions. Inclusion of long aliphatic chains on these ligands allows the assemblies to extract anions from aqueous media into organic solvents. Phosphate can be removed from water efficiently and highly selectively, even in the presence of other anions.
Nanoimpacts at Active and Partially Active Electrodes: Insights and Limitations
Authors: Roehrich Brian , Sepunaru Lior
Published: August 2020

While the electrochemical nanoimpact technique has recently emerged as a method of studying single entities, it is limited by requirement of a catalytically active particle impacting an inert electrode. We show that an active particle‐active electrode can provide mechanistic insight into electrochemical reactions. When an individual Pt electrocatalyst adsorbs to the surface of a partially active electrode, further reduction of electrode‐produced species can proceed on the nanocatalyst. Current transients obtained during hydrogen evolution allow simultaneous measurement of the Pt catalyst over different length scales, size dependency suggests H atom intercalation as a catalytic deactivation mechanism. Although results show that outer‐sphere redox probes are unproductive for particle characterization, the breadth of inner‐sphere electrochemical reactions makes this a promising method for understanding the properties of catalytic nanomaterials, one at a time.
A Photoaffinity‐Based Fragment‐Screening Platform for Efficient Identification of Protein Ligands
Authors: Grant Emma K. , Fallon David J. , Hann Michael M. , Fantom Ken G. M. , Quinn Chad , Zappacosta Francesca , Annan Roland S. , Chung Chun‐wa , Bamborough Paul , Dixon David P. , Stacey Peter , House David , Patel Vipulkumar K. , Tomkinson Nicholas C. O. , Bush Jacob T.
Published: August 2020

Advances in genomic analyses enable the identification of new proteins that are associated with disease. To validate these targets, tool molecules are required to demonstrate that a ligand can have a disease‐modifying effect. Currently, as tools are reported for only a fraction of the proteome, platforms for ligand discovery are essential to leverage insights from genomic analyses. Fragment screening offers an efficient approach to explore chemical space. Presented here is a fragment‐screening platform, termed PhABits (PhotoAffinity Bits), which utilizes a library of photoreactive fragments to covalently capture fragment–protein interactions. Hits can be profiled to determine potency and the site of crosslinking, and subsequently developed as reporters in a competitive displacement assay to identify novel hit matter. The PhABit platform is envisioned to be widely applicable to novel protein targets, identifying starting points in the development of therapeutics.
Highly Regioselective Addition of Allylic Zinc Halides and Various Zinc Enolates to [1.1.1]Propellane
Authors: Schwärzer Kuno , Zipse Hendrik , Karaghiosoff Konstantin , Knochel Paul
Published: August 2020

We report a range of highly regioselective openings of [1.1.1]propellane with various allylic zinc halides, as well as zinc enolates of ketones, esters and nitriles. The resulting zincated bicyclopentanes (BCPs) were trapped with a range of electrophiles including acyl chlorides, sulfonothioates, hydroxylamino benzoates, tosyl cyanide as well as aryl and allyl halides, generating highly functionalized BCP‐derivatives. The unusually high regioselectivity of these reactions has been rationalized using DFT calculations. A bioisostere of the synthetic opioid pethidine was prepared in 95 % yield in one step using this method.
NMR Spectroscopic Characterization of the C‐Mannose Conformation in a Thrombospondin Repeat Using a Selective Labeling Approach
Authors: Jonker Hendrik R. A. , Saxena Krishna , Shcherbakova Aleksandra , Tiemann Birgit , Bakker Hans , Schwalbe Harald
Published: August 2020

Despite the great interest in glycoproteins, structural information reporting on conformation and dynamics of the sugar moieties are limited. We present a new biochemical method to express proteins with glycans that are selectively labeled with NMR‐active nuclei. We report on the incorporation of 13C‐labeled mannose in the C‐mannosylated UNC‐5 thrombospondin repeat. The conformational landscape of the C‐mannose sugar puckers attached to tryptophan residues of UNC‐5 is characterized by interconversion between the canonical 1C4 state and the B03 / 1S3 state. This flexibility may be essential for protein folding and stabilization. We foresee that this versatile tool to produce proteins with selectively labeled C‐mannose can be applied and adjusted to other systems and modifications and potentially paves a way to advance glycoprotein research by unravelling the dynamical and conformational properties of glycan structures and their interactions.
Enzyme‐Inspired Room‐Temperature Lithium–Oxygen Chemistry via Reversible Cleavage and Formation of Dioxygen Bonds
Authors: Wang Chengyi , Zhang Zihe , Liu Weiwei , Zhang Qinming , Wang Xin‐Gai , Xie Zhaojun , Zhou Zhen
Published: August 2020

Li‐O2 batteries are promising energy storage systems due to their ultra‐high theoretical capacity. However, most Li‐O2 batteries are based on the reduction/oxidation of Li2O2 and involve highly reactive superoxide and peroxide species that would cause serious degradation of cathodes, especially carbon‐based materials. It is important to explore lithium‐oxygen reactions and find new Li‐O2 chemistry which can restrict or even avoid the negative influence of superoxide/peroxide species. Here, inspired by enzyme‐catalyzed oxygen reduction/oxidation reactions, we introduce a copper(I) complex 3 N‐CuI (3 N=1,4,7‐trimethyl‐1,4,7‐triazacyclononane) to Li‐O2 batteries and successfully modulate the reaction pathway to a moderate one on reversible cleavage/formation of O−O bonds. This work demonstrates that the reaction pathways of Li‐O2 batteries could be modulated by introducing an appropriate soluble catalyst, which is another powerful choice to construct better Li‐O2 batteries.
Congenital diaphragmatic hernia and maternal dietary nutrient pathways and diet quality
Authors: Carmichael Suzan L. , Ma Chen , Witte John S. , Yang Wei , Rasmussen Sonja A. , Brunelli Luca , Nestoridi Eirini , Shaw Gary M. , Feldkamp Marcia L. ,   National Birth Defects Prevention Study
Published: August 2020

Introduction

We examined the association of congenital diaphragmatic hernia (CDH) with maternal dietary intake, using semi‐Bayes hierarchical models and principal components analysis to consider intake of nutrients that contribute to one‐carbon metabolism and oxidative stress pathways, and a diet quality index.

Methods

We included data on 825 cases and 11,108 nonmalformed controls born from 1997–2011 whose mother participated in the National Birth Defects Prevention Study (NBDPS), a multisite, population‐based case–control study. Exposure data were from maternal telephone interviews, which included a food frequency questionnaire. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were generated from logistic regression models that included nutritional factors as continuous variables and were adjusted for maternal energy intake, race–ethnicity, parity, and vitamin supplement intake.

Results

In the semi‐Bayes hierarchical model that included all nutrients and confounders, riboflavin was the only nutrient for which the 95% CI excluded 1.0; the aOR for a 1 SD increase was 0.83. The aORs were 0.79 (95% CI 0.69–0.91) for the one‐carbon metabolism pathway score, 0.90 (95% CI 0.80–1.01) for oxidative stress, and 0.85 (95% CI 0.77–0.93) for diet quality (the aORs correspond to a 1 SD increase).

Conclusions

The findings from this study provide some support for the hypothesis that better prepregnancy nutrition is associated with reduced risk for CDH. These results provide etiologic clues but should be interpreted with caution given the novelty of the investigation.
Polycomb Repressive Complexes in Hox Gene Regulation: Silencing and Beyond
Authors: Gentile Claudia , Kmita Marie
Published: August 2020

The coordinated expression of the Hox gene family encoding transcription factors is critical for proper embryonic development and patterning. Major efforts have thus been dedicated to understanding mechanisms controlling Hox expression. In addition to the temporal and spatial sequential activation of Hox genes, proper embryonic development requires that Hox genes get differentially silenced in a cell‐type specific manner as development proceeds. Factors contributing to Hox silencing include the polycomb repressive complexes (PRCs), which control gene expression through epigenetic modifications. This review focuses on PRC‐dependent regulation of the Hox genes and is aimed at integrating the growing complexity of PRC functional properties in the context of Hox regulation. In particular, mechanisms underlying PRC binding dynamics as well as a series of studies that have revealed the impact of PRC on the 3D organization of the genome is discussed, which has a significant role on Hox regulation during development.
Recent Advances in the Construction of Flexible Sensors for Biomedical Applications
Authors: Zhou Nan , Liu Tianjiao , Wen Bianying , Gong Coucong , Wei Gang , Su Zhiqiang
Published: August 2020

The fabrication of flexible sensors is a potential way to promote the progress of modern social science and technology due to their wide applications in high‐performance electronic equipment and devices. Flexible sensors based on organic materials combine the unique advantages of flexibility and low cost, increasing interest in healthcare monitoring, treatment, and human–machine interfaces. Advances in materials science and biotechnology have rapidly accelerated the development of bio‐integrated multifunctional sensors and devices. Due to their excellent mechanical and electrical properties, many types of functional materials provided benefits for the construction of various sensors with improved flexibility and stretchability. In this review, recent advance in the fabrication of flexible sensors by using functional nanomaterials including nanoparticles, carbon materials, metal‐organic materials, and polymers is presented. In addition, the potential biomedical applications of the fabricated flexible sensors for detecting gas molecules signals, small molecules, DNA/RNA, proteins, others are introduced and discussed.
Superficial anorectal abscess resembling a lipoma: A case report
Authors: Kogo Hideki , Takasaki Hideaki , Sakata Yoshinori , Nakamura Yoshiharu , Yoshida Hiroshi
Published: August 2020

Perianal abscesses exist in various forms depending on the location. Clinical examination and endorectal ultrasound (EUS) may be useful for the diagnosis of anal tumor.
Determination of Configuration and Conformation of a Reserpine Derivative with Seven Stereogenic Centers Using Molecular Dynamics with RDC‐Derived Tensorial Constraints**
Authors: Sager Emine , Tzvetkova Pavleta , Gossert Alvar D. , Piechon Philippe , Luy Burkhard
Published: August 2020

NMR‐based determination of the configuration of complex molecules containing many stereocenters is often not possible using traditional NOE data and coupling patterns. Making use of residual dipolar couplings (RDCs), we were able to determine the relative configuration of a natural product containing seven stereocenters, including a chiral amine lacking direct RDC data. To identify the correct relative configuration out of 32 possible ones, experimental RDCs were used in three different approaches for data interpretation: by fitting experimental data based singular value decomposition (SVD) using a single alignment tensor and either (i) a single conformer or (ii) multiple conformers, or alternatively (iii) using molecular dynamics simulations with tensorial orientational constraints (MDOC). Even though in all three approaches one and the same configuration could be selected and clear discrimination between possible configurations was achieved, the experimental data was not fully satisfied by the methods based on single tensor approaches. While these two approaches are faster, only MDOC is able to fully reproduce experimental results, as the obtained conformational ensemble adequately covers the conformational space necessary to describe the molecule with inherent flexibility.
Dynamics of Hydrogen Bonding in Three‐Component Nanorotors
Authors: Biswas Pronay Kumar , Goswami Abir , Saha Suchismita , Schmittel Michael
Published: August 2020

The dynamics of hydrogen bonding do not only play an important role in many biochemical processes but also in Nature's multicomponent machines. Here, a three‐component nanorotor is presented where both the self‐assembly and rotational dynamics are guided by hydrogen bonding. In the rate‐limiting step of the rotational exchange, two phenolic O‐H–N,N(phenanthroline) hydrogen bonds are cleaved, a process that was followed by variable‐temperature 1H NMR spectroscopy. Activation data (ΔG≠298=46.7 kJ mol−1 at 298 K, ΔH≠=55.3 kJ mol−1, and ΔS≠=28.8 J mol−1 K−1) were determined, furnishing a rotational exchange frequency of k298=40.0 kHz. Fully reversible disassembly/assembly of the nanorotor was achieved by addition of 5.0 equivalents of trifluoroacetic acid (TFA)/1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) over three cycles.
Stabilization of Linear C3 by Two Donor Ligands: A Theoretical Study of L‐C3‐L (L=PPh3, NHCMe, cAACMe)**
Authors: Gorantla Sai Manoj N. V. T. , Pan Sudip , Mondal Kartik Chandra , Frenking Gernot
Published: August 2020

Quantum chemical studies using density functional theory and ab initio methods have been carried out for the molecules L‐C3‐L with L=PPh3 (1), NHCMe (2, NHC=N‐heterocyclic carbene), and cAACMe (3, cAAC=cyclic (alkyl)(amino) carbene). The calculations predict that 1 and 2 have equilibrium geometries where the ligands are bonded with rather acute bonding angles at the linear C3 moiety. The phosphine adduct 1 has a synclinal (gauche) conformation whereas 2 exhibits a trans conformation of the ligands. In contrast, the compound 3 possesses a nearly linear arrangement of the carbene ligands at the C3 fragment. The bond dissociation energies of the ligands have the order 1<2<3. The bonding analysis using charge and energy decomposition methods suggests that 3 is best described as a cumulene with electron‐sharing double bonds between neutral fragments (cAACMe)2 and C3 in the respective electronic quintet state yielding (cAACMe)=C3=(cAACMe). In contrast, 1 and 2 possess electron‐sharing and dative bonds between positively charged ligands [(PPh3)2]+ or [(NHCMe)2]+ and negatively charged [C3]− fragments in the respective doublet state.
Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer‐Induced Photoreduction in Phospholipid Bilayers
Authors: Pannwitz Andrea , Saaring Holden , Beztsinna Nataliia , Li Xinmeng , Siegler Maxime A. , Bonnet Sylvestre
Published: August 2020

Photosystem I (PS I) is a transmembrane protein that assembles perpendicular to the membrane, and performs light harvesting, energy transfer, and electron transfer to a final, water‐soluble electron acceptor. We present here a supramolecular model of it formed by a bicationic oligofluorene 12+ bound to the bisanionic photoredox catalyst eosin Y (EY2−) in phospholipid bilayers. According to confocal microscopy, molecular modeling, and time dependent density functional theory calculations, 12+ prefers to align perpendicularly to the lipid bilayer. In presence of EY2−, a strong complex is formed (Ka=2.1±0.1×106 m−1), which upon excitation of 12+ leads to efficient energy transfer to EY2−. Follow‐up electron transfer from the excited state of EY2− to the water‐soluble electron donor EDTA was shown via UV–Vis absorption spectroscopy. Overall, controlled self‐assembly and photochemistry within the membrane provides an unprecedented yet simple synthetic functional mimic of PS I.
The Critical Role of Passive Permeability in Designing Successful Drugs
Authors: Di Li , Artursson Per , Avdeef Alex , Benet Leslie Z. , Houston J. Brian , Kansy Manfred , Kerns Edward H. , Lennernäs Hans , Smith Dennis A. , Sugano Kiyohiko
Published: August 2020

Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug‐drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure‐permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients.
Crystal Structures and Phosphorescent Properties of Group 14 Dipyridinometalloles and Their Copper Complexes
Authors: Ohshita Joji , Yamaji Kosuke , Adachi Yohei
Published: August 2020

We recently reported dipyridinosilole (DPyS) and dipyridinogermole (DPyG) as π‐conjugated units that show low‐temperature phosphorescence. A copper complex of DPyG shows solid‐state phosphorescence at room temperature. In this work, we prepared diphenyldipyridinostannole (DPySn1). Its optical and electrochemical properties were investigated and compared with those of DPyS1 and DPyG1 with the same phenyl substituents. DPySn1 showed the most red‐shifted phosphorescence at 520 nm at 77 K in the solid‐state, which is likely due to the intermolecular Sn‐pyridine interaction that was confirmed by single‐crystal X‐ray diffraction. Copper complexes of DPyS1 and DPySn1 were also prepared and it was found that the phosphorescence of these dipyridinometallole‐copper complex solids was red‐shifted in the order of DPySn1−Cu (617 nm)<DPyG1−Cu (624 nm)<DPyS1−Cu (645 nm). Single‐crystal X‐ray diffraction studies were performed for DPyS1−Cu and DPySn1−Cu complexes. DPyS1−Cu showed a double‐chained polymeric ladder‐like structure with Cu4I4 cluster units and DPySn1−Cu possessed a single chain polymeric structure with Cu2I2 units, analogous to DPyG1−Cu.
Cytotoxicity of dental disclosing solution on gingival epithelial cells in vitro
Authors: Jung Im‐hee , Yeon Kyeong Ho , Song Hwi Rin , Hwang Young Sun
Published: August 2020

Objective

Coloring dental biofilm and plaque with a dental disclosing solution is visually effective in dental treatment and oral hygiene education. Despite continuous reports of the risk of the product ingredients, dental disclosing solution are widely used in dentistry. However, the cytotoxic mechanism of dental disclosing solution is not known. Here we elucidated the tissue dyeing range and investigated the cytotoxic mechanism of dental disclosing solution.

Materials and methods

Gingival epithelial cells and mouse head and neck tissue were stained with dental disclosing solution. Changes in the cell cycle distribution by the dental disclosing solution treatment were analyzed. A deoxynucleotidyl transferase dUTP nick and labeling (TUNEL) assay was performed to examine the apoptotic features of the gingival epithelial cells.

Results

Dental disclosing solution stained the chromosome strongly, as well as both the hard and soft tissue of the mouse head and neck. The results of flow cytometric analysis and TUNEL analyses revealed that the cytotoxicity associated with dental disclosing solution was related to the induction of apoptosis. However, the staining of porcine skin by dental disclosing solution was not easily removed, even with a wide range of pH solutions.

Conclusions

These results suggest that dental disclosing solution had strong cytotoxicity and safer alternatives are needed.
Robust Solid‐Electrolyte Interphase Enables Near‐Theoretical Capacity of Graphite Battery Anode at 0.2 C in Propylene Carbonate‐Based Electrolyte
Authors: Han Jisoo , Chung Gyeong Jun , Song Seung‐Wan
Published: August 2020

The formation of a robust solid‐electrolyte interphase (SEI) layer at the surface of a graphite anode by electrolyte control is a key technology for high‐performance lithium‐ion batteries. Although propylene carbonate (PC) offers a lower melting point than ethylene carbonate, its combination with the graphite anode without additive is a worse choice, owing to co‐intercalation of PC and Li+ ion into graphite, exfoliation of graphene sheets, and death of the battery. This study reports a graphite anode with an unprecedentedly high initial coulombic efficiency of 94 %, close to theoretical capacity, and excellent capacity retention of 99 % after 100 cycles in a PC‐based electrolyte system, even at an unusually high rate of 0.2 C, which is generally attainable only at a very low rate of below 0.05 C in commercial electrolyte. The SEI stabilization for a graphite anode in PC‐based electrolyte provides a new avenue for high‐energy and high‐performance batteries in widened range of working temperatures. A strong correlation between anode‐electrolyte interfacial stabilization and highly reversible cycling performance is clearly demonstrated.
Comparative node selection‐based localization technique for wireless sensor networks: A bilateration approach
Authors: Tabassum Nikhath , Devanagavi Geetha D. , Biradar Rajashekhar C. , Lazarescu Mihai T.
Published: August 2020

Wireless sensor networks find extensive applications, such as environmental and smart city monitoring, structural health, and target location. To be useful, most sensor data must be localized. We propose a node localization technique based on bilateration comparison (BACL) for dense networks, which considers two reference nodes to determine the unknown position of a third node. The mirror positions resulted from bilateration are resolved by comparing their coordinates with the coordinates of the reference nodes. Additionally, we use network clustering to further refine the location of the nodes. We show that BACL has several advantages over Energy Aware Co‐operative Localization (EACL) and Underwater Recursive Position Estimation (URPE): (1) BACL uses bilateration (needs only two reference nodes) instead of trilateration (that needs three reference nodes), (2) BACL needs reference (anchor) nodes only on the field periphery, and (3) BACL needs substantially less communication and computation. Through simulation, we show that BACL localization accuracy, as root mean square error, improves by 53% that of URPE and by 40% that of EACL. We also explore the BACL localization error when the anchor nodes are placed on one or multiple sides of a rectangular field, as a trade‐off between localization accuracy and network deployment effort. Best accuracy is achieved using anchors on all field sides, but we show that localization refinement using node clustering and anchor nodes only on one side of the field has comparable localization accuracy with anchor nodes on two sides but without clustering.
Pioneer use of gene expression programming for predicting seasonal streamflow in Australia using large scale climate drivers
Authors: Esha Rijwana , Imteaz Monzur Alam
Published: August 2020

This paper presents development of an artificial intelligence (AI)‐based model, genetic expression programming (GEP) to predict long‐term streamflow using large‐scale climate drivers as predictors. GEP is chosen over artificial neural networks (ANNs) model, as ANN is a black‐box model, whereas GEP is able to explain the developed forecast models with mathematical expressions. As a case study, 12 streamflow measuring stations were selected from four different regions of New South Wales (NSW) in eastern Australia. A number of climate indices, Pacific Decadal Oscillation (PDO), Indian Ocean Dipole (IOD), El Nino Southern Oscillation (ENSO) and ENSO Modoki index (EMI), were selected as candidate predictors based on the findings of some preliminary studies. Higher predictabilities of the GEP‐based models are evident from the Pearson correlation (r) values ranging between 0.57 and 0.97, which are mostly about twice the values achieved by multiple linear regression (MLR) models in the preliminary study. Performances of the developed models were assessed using standard statistical measures such as root relative squared error (RRSE), relative absolute error (RAE), root mean square error (RMSE), mean absolute error (MAE), Nash–Sutcliffe efficiency (NSE) and Pearson correlation (r) values. The developed models are able to predict spring streamflow up to 5 months in advance with significantly high correlation values.
Bis‐NHC Aluminium and Gallium Dihydride Cations [(NHC)2EH2]+ (E = Al, Ga)
Authors: Hock Andreas , Werner Luis , Riethmann Melanie , Radius Udo
Published: August 2020

The NHC alane and gallane adducts (NHC)·AlH2I (NHC = Me2ImMe 7, iPr2Im 8, iPr2ImMe 9) and (NHC)·GaH2I (NHC = Me2ImMe 10, iPr2ImMe 11, Dipp2Im 12; R2Im = 1,3‐di‐organyl‐imidazolin‐2‐ylidene; Dipp = 2,6‐diisopropylphenyl; iPr = isopropyl; Me2ImMe = 1,3,4,5‐tetra‐methyl‐imidazolin‐2‐ylidene) were prepared either by the simple yet efficient reaction of the NHC adduct (NHC)·AlH3 with elemental iodine or by the treatment of (NHC)·GaH3 with an excess of methyl iodide at room temperature. The reaction of one equivalent of the group 13 NHC complexes with an additional equivalent of the corresponding NHC afforded cationic aluminium and gallium hydrides [(NHC)2·AlH2]+I− (NHC = Me2ImMe 13, iPr2Im 14, iPr2ImMe 15) and [(NHC)2·GaH2]+I− (NHC = Me2ImMe 16, iPr2ImMe 17) and the normal and abnormal NHC coordinated compound [(Dipp2Im)·GaH2(aDipp2Im)]+I− 18. Compounds 7–18 were isolated and characterized by means of elemental analysis, IR and multinuclear NMR spectroscopy and by X‐ray diffraction of the compounds 7, 9, 10, 15, 16 and 18.
Synthesis of Clausenal, 1,5‐Dimethoxycarbazole‐3‐carbaldehyde and 2,5‐Dimethoxycarbazole‐3‐carbaldehyde
Authors: Kishonti Adrian , Jäger Anne , Knölker Hans‐Joachim
Published: August 2020

Clausenal (1,8‐dimethoxycarbazole‐3‐carbaldehyde) represents the only known naturally occurring 1,8‐dioxygenated carbazole alkaloid. However, the structural assignment for clausenal has recently been questioned because of some discrepancies between a synthetic sample and the natural product with respect to NMR data and melting points. Therefore, we have synthesized clausenal as well as two potential structural alternatives (1,5‐dimethoxycarbazole‐3‐carbaldehyde and 2,5‐dimethoxycarbazole‐3‐carbaldehyde) and compared their spectroscopic data with those reported for the isolated natural product. In conclusion from our investigation, we assume that the original structural assignment reported for clausenal most likely is correct.
Mobile containers in human cognitive evolution studies: Understudied and underrepresented
Authors: Langley Michelle C. , Suddendorf Thomas
Published: August 2020

Mobile carrying devices—slings, bags, boxes, containers, etc.—are a ubiquitous tool form among recent human communities. So ingrained are they to our present lifeways that the fundamental relationship between mobile containers and foresight is easily overlooked, resulting in their significance in the study of human cognitive development being largely unrecognized. Exactly when this game‐changing innovation appeared and became an essential component of the human toolkit is currently unknown. Taphonomic processes are obviously a significant factor in this situation; however, we argue that these devices have also not received the attention that they deserve from human evolution researchers. Here we discuss what the current archeological evidence is for Pleistocene‐aged mobile containers and outline the various lines of evidence that they provide for the origins and development of human cognitive and cultural behavior.
A novel seed dispersal mode ofApostasia nipponicacould provide some clues to the early evolution of the seed dispersal system in Orchidaceae
Authors: Suetsugu Kenji
Published: August 2020

Despite being one of the most diverse families, scant attention has been paid to the seed dispersal system in Orchidaceae, owing to the widely accepted notion that wind dispersal is the dominant strategy. However, the indehiscent fruits, with seeds immersed in fleshy tissue, evoke the possibility of endozoochory in Apostasioideae, the earliest diverging lineage of orchids. In the present study, I investigated the seed dispersal system of Apostasia nipponica by direct observation, time-lapse photography, and investigation of the viability of seeds passing through the digestive tract of orthopterans. This study revealed a previously undocumented seed dispersal system in A. nipponica, in which the cricket, Eulandrevus ivani, and the camel cricket, Diestrammena yakumontana, consume the fruit and defecate viable seeds. Orthopterans are rarely considered seed dispersers, but the gross fruit morphology and pigmentation patterns of some Apostasia species parallel those seen in A. nipponica, suggesting that similar seed dispersal systems could be widespread among Apostasia species. Whether seed dispersal by orthopteran frugivores is common in Apostasioideae warrants further investigation.
Repetitive injury and absence of monocytes promote astrocyte self‐renewal and neurological recovery
Authors: Lange Canhos Luisa , Chen Muxin , Falk Sven , Popper Bastian , Straub Tobias , Götz Magdalena , Sirko Swetlana
Published: August 2020

Unlike microglia and NG2 glia, astrocytes are incapable of migrating to sites of injury in the posttraumatic cerebral cortex, instead relying on proliferation to replenish their numbers and distribution in the affected region. However, neither the spectrum of their proliferative repertoire nor their postinjury distribution has been examined in vivo. Using a combination of different thymidine analogs and clonal analysis in a model of repetitive traumatic brain injury, we show for the first time that astrocytes that are quiescent following an initial injury can be coerced to proliferate after a repeated insult in the cerebral cortex grey matter. Interestingly, this process is promoted by invasion of monocytes to the injury site, as their genetic ablation (using CCR2−/− mice) increased the number of repetitively dividing astrocytes at the expense of newly proliferating astrocytes in repeatedly injured parenchyma. These differences profoundly affected both the distribution of astrocytes and recovery period for posttraumatic behavior deficits suggesting key roles of astrocyte self‐renewal in brain repair after injury.
A Fibrosis‐Independent Hepatic Transcriptomic Signature Identifies Drivers of Disease Progression in Primary Sclerosing Cholangitis
Authors: Gindin Yevgeniy , Chung Chuhan , Jiang Zhaoshi , Zhou Jing Zhu , Xu Jun , Billin Andrew N. , Myers Robert P. , Goodman Zachary , Landi Abdolamir , Houghton Michael , Green Richard M. , Levy Cynthia , Kowdley Kris V. , Bowlus Christopher L. , Muir Andrew J. , Trauner Michael
Published: August 2020

Background and Aims

Primary sclerosing cholangitis (PSC) is a heterogeneous cholangiopathy characterized by progressive biliary fibrosis. RNA sequencing of liver tissue from patients with PSC (n = 74) enrolled in a 96‐week clinical trial was performed to identify associations between biological pathways that were independent of fibrosis and clinical events.

Approach and Results

The effect of fibrosis was subtracted from gene expression using a computational approach. The fibrosis‐adjusted gene expression patterns were associated with time to first PSC‐related clinical event (e.g., cholangitis, hepatic decompensation), and differential expression based on risk groups and Ingenuity Pathway Analysis were performed. Baseline demographic data were representative of PSC: median age 48 years, 71% male, 49% with inflammatory bowel disease, and 44% with bridging fibrosis or cirrhosis. The first principle component (PC1) of RNA‐sequencing data accounted for 18% of variance and correlated with fibrosis stage (ρ = −0.80; P < 0.001). After removing the effect of fibrosis‐related genes, the first principle component was not associated with fibrosis (ρ = −0.19; P = 0.11), and a semisupervised clustering approach identified two distinct patient clusters with differential risk of time to first PSC‐related event (P < 0.0001). The two groups had similar fibrosis stage, hepatic collagen content, and α‐smooth muscle actin expression by morphometry, Enhanced Liver Fibrosis score, and serum liver biochemistry, bile acids, and IL‐8 (all P > 0.05). The top pathways identified by Ingenuity Pathway Analysis were eukaryotic translation inhibition factor 2 (eIF2) signaling and regulation of eIF4/p70S6K signaling. Genes involved in the unfolded protein response, activating transcription factor 6 (ATF6) and eIF2, were differentially expressed between the PSC clusters (down‐regulated in the high‐risk group by log‐fold changes of −0.18 [P = 0.02] and −0.16 [P = 0.02], respectively). Clinical events were enriched in the high‐risk versus low‐risk group (38% [12/32] vs. 2.4% [1/42], P < 0.0001).

Conclusions

Removing the contribution of fibrosis‐related pathways uncovered alterations in the unfolded protein response, which were associated with liver‐related complications in PSC.