bluuebunny/crossref_metadata_2025 huggingface dataset:
CSF chitinases before and after symptom onset in amyotrophic lateral sclerosis
Authors: Gray Elizabeth , Thompson Alexander G. , Wuu Joanne , Pelt Joe , Talbot Kevin , Benatar Michael , Turner Martin R.
Published: July 2020

Objective

To evaluate the CSF levels of chitinase proteins during the presymptomatic and early symptomatic phases of amyotrophic lateral sclerosis (ALS).

Methods

CSF samples were obtained from 16 controls, 55 individuals at‐risk for ALS (including 18 carrying a mutation in C9ORF72, 33 in SOD1), 12 ALS patients, and 7 phenoconverters (individuals diagnosed with ALS during follow‐up). At‐risk individuals and phenoconverters were enrolled through the Pre‐fALS study, which includes individuals carrying an ALS‐associated gene mutation without disease manifestations at initial assessment. Longitudinal CSF collections, where possible, took place every 3‐12 months for ALS patients and every 1‐2 years for others. CSF levels of chitotriosidase 1 (CHIT1), chitinase‐3‐like protein 1 (CHI3L1, YKL‐40) and chitinase‐3‐like protein 2 (CHI3L2, YKL‐39) were measured by ELISA, along with CHIT1 activity. Longitudinal changes in at‐risk individuals and phenoconverters were fitted to linear mixed effects models.

Results

Slowly rising levels of CHIT1 were observed over time in the at‐risk individuals (slope 0.059 log10[CHIT1] per year, P < 0.001). Among phenoconverters, CHIT1 levels and activity rose more sharply (0.403 log10[CHIT1] per year, P = 0.005; 0.260 log10[CHIT1 activity] per year, P = 0.007). Individual levels of both CHI3L1 and CHI3L2 remained relatively stable over time in all participant groups.

Interpretation

The CHIT1 neuroinflammatory response is a feature of the late presymptomatic to early symptomatic phases of ALS. This study does not suggest a long prodrome of upregulated glial activity in ALS pathogenesis, but strengthens the place of CHIT1 as part of a panel of biomarkers to objectively assess the impact of immune‐modulatory therapeutic interventions in ALS.
Rationally Designed Vanadium Pentoxide as High Capacity Insertion Material for Mg‐Ion
Authors: Mukherjee Ayan , Taragin Sarah , Aviv Hagit , Perelshtein Ilana , Noked Malachi
Published: July 2020

Owing to high energy density and economic viability, rechargeable Mg batteries are considered alternatives to lithium ion batteries. However besides the chevrel phase, none of the conventional inorganic cathode materials demonstrate reversible intercalation/deintercalation of Mg+2 ions in an anhydrous electrolyte system. The lack of high voltage and high capacity cathode frustrates the realization of Mg batteries. Previous studies indicate that vanadium pentoxide (V2O5) has the potential to reversibly insert/extract Mg ions. However, many attempts to utilize V2O5 demonstrate limited electrochemical response, due to hindered Mg ion mobility in solid. Here, monodispersed spherical V2O5 with a hierarchical architecture is rationally designed, through a facile and scalable approach. The V2O5 spheres exhibit initial discharge capacity of 225 mA h g−1 which stabilizes at ≈190 mA h g−1 at 10 mA g−1, much higher than previous reports. The V2O5 spheres exhibit specific discharge capacity of 55 mA h g−1 at moderate current rate (50 mA g−1) with negligible fading after 50 cycles (≈5%) and 100 cycle (≈13%), while it retains ≈95% columbic efficiency after 100 cycles demonstrating excellent stability during Mg+2 ion intercalation/deintercalation. Most interestingly, exact phase and morphology are completely retained even after repeated Mg+2 ion intercalation/deintercalation at different current rates, demonstrating pronounced electrochemical activity in an anhydrous magnesium electrolyte.
Borophene: New Sensation in Flatland
Authors: Ranjan Pranay , Lee Jang Mee , Kumar Prashant , Vinu Ajayan
Published: July 2020

Borophene, a 2D allotrope of boron and the lightest elemental Dirac material, is the latest very promising 2D material owing to its unique structural and electronic characteristics of the X3 and β12 phases. The high atomic density on ridgelines of the β12 phase of borophene provides a substantial orbital overlap, which leads to an excellent electron density in the conduction level and thus to a highly metallic behavior. These unique structural characteristics and electronic properties of borophene attract significant scientific interest. Herein, approaches for crystal growth/synthesis of these unique nanostructures and their potential technological applications are discussed. Various substrate‐supported ultrahigh‐vacuum growth techniques for borophene, such as molecular beam epitaxy, atomic layer deposition, and chemical vapor deposition, along with their challenges, are also summarized. The sonochemical exfoliation and modified Hummer's technique for the synthesis of free‐standing borophene are also discussed. Solution‐phase exfoliation seems to address the scalability issues and expands the applications of these unique materials to various fields, including renewable energy devices and ultrafast sensors. Furthermore, the electronic, optical, thermal, and elastic properties of borophene are thoroughly discussed and are compared with those of graphene and its “cousins.” Numerous frontline applications are envisaged and an outlook is presented.
Ultrathin Low‐Crystallinity MOF Membranes Fabricated by Interface Layer Polarization Induction
Authors: Qiao Zhihua , Liang Yueyao , Zhang Zhengqing , Mei Donghai , Wang Zhi , Guiver Michael D. , Zhong Chongli
Published: July 2020

Practical, ultrathin metal‐organic framework (MOF) membranes have the potential to achieve otherwise difficult separations, but current fabrication methods still face challenges in the simultaneous improvement of both selectivity and permeance. Here, ultrathin, low‐crystallinity‐state MOF (LC‐MOF) membranes are realized by a facile general method of interface layer polarization induction. This is achieved using an interface layer having metal ions with dense and uniform distribution, resulting in the creation of abundant open metal sites. Three types of LC‐MOF membranes (45–150 nm) are fabricated, among which ZIF‐8 membranes modified in situ with diethanolamine (DZIF‐8) display the best performance for propylene/propane separation, showing unprecedented propylene permeance (2000–3000 Gas Permeance Units) with very high propylene/propane selectivity (90–120).
Dielectric Properties of Ultrathin CaF2 Ionic Crystals
Authors: Wen Chao , Banshchikov Alexander G. , Illarionov Yury Y. , Frammelsberger Werner , Knobloch Theresia , Hui Fei , Sokolov Nikolai S. , Grasser Tibor , Lanza Mario
Published: July 2020

Mechanically exfoliated 2D hexagonal boron nitride (h‐BN) is currently the preferred dielectric material to interact with graphene and 2D transition metal dichalcogenides in nanoelectronic devices, as they form a clean van der Waals interface. However, h‐BN has a low dielectric constant (≈3.9), which in ultrascaled devices results in high leakage current and premature dielectric breakdown. Furthermore, the synthesis of h‐BN using scalable methods, such as chemical vapor deposition, requires very high temperatures (>900 °C) , and the resulting h‐BN stacks contain abundant few‐atoms‐wide amorphous regions that decrease its homogeneity and dielectric strength. Here it is shown that ultrathin calcium fluoride (CaF2) ionic crystals could be an excellent solution to mitigate these problems. By applying >3000 ramped voltage stresses and several current maps at different locations of the samples via conductive atomic force microscopy, it is statistically demonstrated that ultrathin CaF2 shows much better dielectric performance (i.e., homogeneity, leakage current, and dielectric strength) than SiO2, TiO2, and h‐BN. The main reason behind this behavior is that the cubic crystalline structure of CaF2 is continuous and free of defects over large regions, which prevents the formation of electrically weak spots.
Biopolymer‐Based Coatings: Promising Strategies to Improve the Biocompatibility and Functionality of Materials Used in Biomedical Engineering
Authors: Song Jian , Winkeljann Benjamin , Lieleg Oliver
Published: July 2020

It was a physicist, Wolfgang Pauli, who recognized a century ago that “God made the bulk; the surface was invented by the devil.” And indeed, adjusting the surface properties of materials has kept engineers and chemists busy since—and it still does. In the context of biomedical engineering, the key challenge is ensuring the functionality of an artificial object, which is inserted into the human body—an environment that passively and actively rejects foreign materials. Here, recent advances in this area while focusing on those approaches that employ surface coating strategies with biopolymers are summarized.
High‐Performance Static Induction Transistors Based on Small‐Molecule Organic Semiconductors
Authors: Guo Erjuan , Xing Shen , Dollinger Felix , Wu Zhongbin , Tahn Alexander , Löffler Markus , Leo Karl , Kleemann Hans
Published: July 2020

The polymeric organic‐static‐induction transistor (OSIT), a solid‐state vacuum triode, has been extensively studied as a promising vertical organic thin‐film transistor. By utilizing polymers as organic semiconductors in OSITs, important performance figures have been achieved, for example, a maximum on‐current output of about 10 mA cm−2, on/off current ratio as high as 105, and a large current gain of 1000. However, even though polymers with higher mobility have been developed, the performance of OSITs has not been significantly improved yet. In this work, record‐high performance OSITs with small‐molecule materials as organic semiconductors are demonstrated. Pentacene as a hole‐transport material for p‐type OSITs can be easily deposited into pinholes of the gate electrode, hence creating effective conducting channels. Excellent characteristics, such as a high on‐current greater than 260 mA cm−2, on/off current ratio up to 3.3 × 105, and a large transmission factor of 99.98% as well as high current gain of 7965, are attained. These results make the small‐molecule organic semiconductor a candidate material for vertical OSITs as well as for organic electronics.
A Ternary Dumbbell Structure with Spatially Separated Catalytic Sites for Photocatalytic Overall Water Splitting
Authors: Qiu Bocheng , Cai Lejuan , Zhang Ning , Tao Xiaoming , Chai Yang
Published: July 2020

Solar‐driven overall water splitting based on metal sulfide semiconductor photocatalysts remains as a challenge owing to the strong charge recombination and deficient catalytic active sites. Additionally, significant inhibition of back reactions, especially the oxidation of sulfide ions during the photocatalytic water oxidation catalysis, is an arduous task that requires an efficient photogenerated hole transfer dynamics. Here, a ternary dumbbell‐shaped catalyst based on RuO2/CdS/MoS2 with spatially separated catalytic sites is developed to achieve simultaneous production of hydrogen and oxygen under simulated solar‐light without any sacrificial agents. Particularly, MoS2 nanosheets anchored on the two ends of CdS nanowires are identified as a reduction cocatalyst to accelerate hydrogen evolution, while RuO2 nanoparticles as an oxidation cocatalyst are deposited onto the sidewalls of CdS nanowires to facilitate oxygen evolution kinetics. The density functional theory simulations and ultrafast spectroscopic results reveal that photogenerated electrons and holes directionally migrate to MoS2 and RuO2 catalytic sites, respectively, thus achieving efficient charge carrier separation. The design of ternary dumbbell structure guarantees metal sulfides against photocorrosion and thus extends their range in solar water splitting.
All‐Paper, All‐Organic, Cuttable, and Foldable Pressure Sensor with Tuneable Conductivity Polypyrrole
Authors: Zhao Pengfei , Zhang Ruimin , Tong Yanhong , Zhao Xiaoli , Tang Qingxin , Liu Yichun
Published: July 2020

Paper has been extensively accepted as an ideal platform for fabricating low‐cost, flexible, and environmentally friendly electronics. However, current paper‐based pressure sensors have not fully demonstrated the unique merits of paper, such as cost efficiency, disposability, cuttability, and foldability, mainly because of the limitation of the applied metal electrodes and device configuration. Here, an all‐organic, all‐paper, cuttable, and foldable pressure sensor is demonstrated for the first time, with the high‐conductivity polypyrrole (PPy) printing paper as electrode and the low‐conductivity PPy tissue paper as active layer. Hollow and 3D all‐paper sensors are realized through fabricating the kirigami or origami structure since the device can be freely cut and folded, presenting a universal strategy promising for flexible device design. The cuttability and foldability of device create a unique 3D perception capability. The devices show high sensitivity (4.8 kPa−1 at < 5.5 kPa, 1.7 kPa−1 at 5.5–40 kPa) and wide detection range (up to 40 kPa), providing a capability for full‐range detection of human physiological and motion signals. These results open a feasible route to realize hollow and 3D sensors and fully demonstrate the potential of paper sensors for diverse applications to new‐generation green electronics and portable electronics.
Heavily Crosslinked, High‐k Ultrathin Polymer Dielectrics for Flexible, Low‐Power Organic Thin‐Film Transistors (OTFTs)
Authors: Choi Junhwan , Kang Juyeon , Lee Changhyeon , Jeong Kihoon , Im Sung Gap
Published: July 2020

High dielectric constant (k) and excellent insulating performance together with the thickness down‐scalability are essential requirements for polymer dielectrics to realize the stable operation of flexible, low‐power electronics. Crosslinking has been applied frequently to the dielectric polymer matrix to enhance the insulating performance. However, the addition of crosslinker into the polymer has been often accompanied by the reduction of the dielectric constant thereof. Herein, a series of copolymer dielectrics is synthesized composed of two monomers of 2‐cyanoethyl acrylate (CEA) possessing a highly polar cyanide functional group and 1,4‐butanediol divinyl ether (BDDVE), a crosslinker with relatively short chain length. The chemical composition of the 30‐nm‐thick copolymer dielectrics is optimized to achieve extremely low leakage current (<3.0 × 10−8 A cm−2 in the range of ± 2 MV cm−1) with unprecedentedly high dielectric constant of 7.5, which is, to the knowledge, the highest dielectric constant among the sub‐50 nm polymer dielectrics without inorganic component, reported to date. Exploiting the copolymer dielectric layers, high‐performance, low‐power organic thin‐film transistors (OTFTs) with high operational stability and extreme mechanical flexibility are demonstrated. It is believed that the high‐k dielectric copolymer films presented in this study will be an important guideline to develop future flexible, wearable electronics.
Morphometric Cell Classification for Single‐Cell MALDI‐Mass Spectrometry Imaging
Authors: Ščupáková Klára , Dewez Frédéric , Walch Axel K. , Heeren Ron M. A. , Balluff Benjamin
Published: July 2020

The large‐scale and label‐free molecular characterization of single cells in their natural tissue habitat remains a major challenge in molecular biology. We present a method that integrates morphometric image analysis to delineate and classify individual cells with their single‐cell‐specific molecular profiles. This approach provides a new means to study spatial biological processes such as cancer field effects and the relationship between morphometric and molecular features.
Novel 2‐hydroxynaphthalene‐based fluorescent turn‐on sensor for highly sensitive and selective detection of Al3+ and its application in imaging in vitro and in vivo
Authors: Xu Ling‐Wen , Wang Xin‐Tian , Zou Yun‐Hong , Yu Xu‐Ya , Xie Cheng‐Zhi , Qiao Xin , Li Qing‐Zhong , Xu Jing‐Yuan
Published: July 2020

Excessive aluminum exposure in the human body has been held responsible for multiple adverse effects, and existing data underscore the significance of aluminum detection in environmental and biological systems. Developing high‐performance Al3+ fluorescent chemosensors can revolutionize our understanding of the physiological and pathological processes of Al3+ ions. Herein, we reported a highly sensitive and selective Schiff base fluorescence sensor, bis‐NAPPD (1,1'‐((1E,1'E)‐(pyridine‐2,3‐diylbis(azanylylidene))bis(methanylylidene))bis(naphthalen‐2‐ol)), which can recognize Al3+ ions and exhibits a remarkable turn‐on dual emission response (by ~23 fold) with a low nanomolar level detection limit (1.67 × 10−8 M) in methanol. Furthermore, the binding behavior and the turn‐on fluorescence probing mechanism of bis‐NAPPD were illustrated in detail by UV–vis titration, 1H NMR, and ESI‐MS spectroscopy as well as density functional theory calculations. Notably, bis‐NAPPD showed great potential for tracing Al3+ distribution in cells and living zebrafish larvae, and can also be applied in the fluorimetric detection of aluminum in sucralfate tablets with good precision and satisfactory accuracy, which may represent a promising Al3+ probe in bioimaging and biomedical applications.
Total Synthesis of Macrocyclic Dysoxylactam A
Authors: Prabhakar Reddy D. , Yu Biao
Published: July 2020

The total synthesis of dysoxylactam A, a novel 17‐membered macrolactam with potent multi‐drug‐resistant reversing activities, has been achieved, starting from 4‐pentene‐1‐al in a longest linear sequence of 17 steps and 9.5% overall yield. The key transformations consist of iterative aldol and ring‐closing metathesis reactions for the construction of the stereochemically enriched polypropionate scaffold and the macrocycle, respectively.
The HPA Axis under Stress and Aging: Individual Vulnerability is Associated with Behavioral Patterns and Exposure Time
Authors: Goncharova Nadezhda D.
Published: July 2020

With aging, incidence of severe stress‐related diseases increases. However, mechanisms, underlying individual vulnerability to stress and age‐related diseases are not clear. The goal of this review is to analyze finding from the recent literature on age‐related characteristics of the hypothalamic‐pituitary‐adrenal (HPA) axis associated with stress reactivity in animals that show behavioral signs of anxiety and depression under mild stress, and in human patients with anxiety disorders and depression with emphasis on the impact of the circadian rhythm and the negative feedback mechanisms involved in the stress response. One can conclude that HPA axis reaction to psycho‐emotional stress, at least acute stress, increases in the aged individuals with anxiety and depression behavior. Elevated stress reactivity is associated with disruption of the circadian rhythm and the mineralocorticoid receptor‐mediated glucocorticoid negative feedback. The disordered function of the HPA axis in individuals with anxiety and depression behavior can contribute to aging‐related pathology.
Wide‐surface pore microfiltration membrane drastically improves sieving decay in TFF‐based perfusion cell culture and streamline chromatography integration for continuous bioprocessing
Authors: Pinto Nuno D. S. , Brower Mark
Published: July 2020

Although several compelling benefits for bioprocess intensification have been reported, the need for a streamlined integration of perfusion cultures with capture chromatography still remains unmet. Here, a robust solution is established by conducting tangential flow filtration‐based perfusion with a wide‐surface pore microfiltration membrane. The resulting integrated continuous bioprocess demonstrated negligible retention of antibody, DNA, and host cell proteins in the bioreactor with average sieving coefficients of 98 ± 1%, 124 ± 28%, and 109 ± 27%, respectively. Further discussion regarding the potential membrane fouling mechanisms is also provided by comparing two membranes with different surface pore structures and the same hollow fiber length, total membrane area, and chemistry. A cake‐growth profile is reported for the narrower surface pore, 0.65‐µm nominal retention perfusion membrane with final antibody sieving coefficients ≤70%. Whereas the sieving coefficient remained ≥85% during 40 culture days for the wide‐surface pore, 0.2‐µm nominal retention rating membrane. The wide‐surface pore structure, confirmed by scanning electron microscopy imaging, minimizes the formation of biomass deposits on the membrane surface and drastically improves product sieving. This study not only offers a robust alternative for integrated continuous bioprocess by eliminating additional filtration steps while overcoming sieving decay, but also provides insight into membranes' fouling mechanism.
A novel TFG c.793C>G mutation in a Chinese pedigree with Charcot‐Marie‐Tooth disease 2
Authors: Wu Ding‐Wen , Li Yanfang , Yin Xinzhen , Zhang Baorong
Published: July 2020

Introduction

Mutations within TFG gene were recently reported to cause Charcot‐Marie‐Tooth disease 2 (CMT2). However, only few pedigrees were documented so far. Here, we reported a Chinese CMT2 pedigree with 8 affected cases and a novel TFG mutation.

Methods

Clinical evaluation and electrophysiological study were performed in all the affected individuals. Whole‐exome sequencing was conducted, followed by the Sanger sequencing and co‐segregation analysis to verify the variants.

Results

All cases presented with a phenotype of CMT2, including slowly progressive symmetrical muscle atrophy and weakness predominantly in the distal limbs. Sensory loss in the distal limbs was present in the proband and his father. Age at onset ranged from 37 to 44 years, and was younger in male cases, compared with female cases. Nerve conduction study revealed normal motor nerve conduction velocity but decreased compound muscle action potential. Electromyography test revealed fibrillation potential and positive sharp waves. The creatine kinase activity was increased in all cases. After genetic investigations, we identified a novel TFG c.793C>G (p.Pro265Ala) mutation in the family. This mutation alters the conserved amino acid residue and is absent in 1000G, ExAC, dbSNP, EP6500, and 200 in‐house controls. It co‐segregated with the disease in the family.

Conclusions

Our report provided additional evidence that the heterozygous TFG mutations were associated with CMT2.
Dual MGMT inactivation by promoter hypermethylation and loss of the long arm of chromosome 10 in glioblastoma
Authors: Richard Sophie , Tachon Gaëlle , Milin Serge , Wager Michel , Karayan‐Tapon Lucie
Published: July 2020

Background

Epigenetic inactivation of O6‐methylguanine‐methyltransferase (MGMT) gene by methylation of its promoter is predictive of Temozolomid (TMZ) response in glioblastoma (GBM). MGMT is located on chromosome 10q26 and the loss of chromosome 10q is observed in 70% of GBMs. In this study, we assessed the hypothesis that the dual inactivation of MGMT, by hypermethylation of MGMT promoter and by loss the long arm of chromosome 10 (10q), may confer greater sensitivity to TMZ.

Methods

A total of 149 tumor samples from patients diagnosed with GBM based on the WHO 2016 classification were included in this retrospective study between November 2016 and December 2018. Methylation status of MGMT promoter was evaluated by pyrosequencing and status of chromosome 10q was assessed by array comparative genomic hybridization.

Results

Glioblastoma patients with chromosome 10q loss associated with hypermethylation of MGMT promoter had significantly longer overall survival (OS) (P = .0024) and progression‐free survival (PFS) (P = .031). Indeed, median OS of patients with dual inactivation of MGMT was 21.5 months compared to 12 months and 8.1 months for groups with single MGMT inactivation by hypermethylation and by 10q loss, respectively. The group with no MGMT inactivation had 9.5 months OS. Moreover, all long‐term survivors with persistent response to TMZ treatment (OS ≥ 30 months) displayed dual inactivation of MGMT.

Conclusions

Our data suggest that the molecular subgroup characterized by the dual inactivation of MGMT receives greater benefit from TMZ treatment. The results of our study may be of immediate clinical interest since chromosome 10q status and methylation of MGMT promoter are commonly determined in routine practice.
Organic defaults in online‐shopping: Immediate effects but no spillover to similar choices
Authors: Kuhn Sascha , Ihmels Max , Kutzner Florian
Published: July 2020

Changing defaults—the preselection that becomes effective without active choice—is becoming a prominent policy tool, after having been proven to be effective in areas as varied as retirement savings, organ donation and product customization. Yet, little is known about how default effects spill over to subsequent similar behaviors. In an online shopping scenario, we found standard default effects on the share of organically produced products in the overall selection of products. These effects did not spill over to subsequent active shopping choices. This was true for defaults that were hard and easy to change (Exp. 1, N = 90), for immediate and delayed subsequent choices (Exp. 2, N = 106) and for self‐selected defaults (Exp. 3, N = 181). These findings suggest that the reach and scalability of default manipulations in policy making may be limited, but also speak against the possibility for negative spillover.
Bioimaging and Biodistribution of the Metal‐Ion‐Controlled Self‐Assembly of PYY3–36 Studied by SPECT/CT
Authors: Kalomoiri Panagiota , Rodríguez‐Rodríguez Cristina , Sørensen Kasper K. , Bergamo Marta , Saatchi Katayoun , Häfeli Urs O. , Jensen Knud J.
Published: July 2020

The controlled self‐assembly of peptide‐ and protein‐based pharmaceuticals is of central importance for their mode of action and tuning of their properties. Peptide YY3–36 (PYY3–36) is a 36‐residue peptide hormone that reduces food intake when peripherally administered. Herein, we describe the synthesis of a PYY3–36 analogue functionalized with a metal‐ion‐binding 2,2’‐bipyridine ligand that enables self‐assembly through metal complexation. Upon addition of CuII, the bipyridine‐modified PYY3–36 peptide binds stoichiometric quantities of metal ions in solution and contributes to the organization of higher‐order assemblies. In this study, we aimed to explore the size effect of the self‐assembly in vivo by using non‐invasive quantitative single‐photon emission computed tomography/computed tomography (SPECT/CT) imaging. For this purpose, bipyridine‐modified PYY3–36 was radiolabeled with a chelator holding 111InIII, followed by the addition of CuII to the bipyridine ligand. SPECT/CT imaging and biodistribution studies showed fast renal clearance and accumulation in the kidney cortex. The radiolabeled bipyridyl‐PYY3–36 conjugates with and without CuII presented a slightly slower excretion 1 h post injection compared to the unmodified‐PYY3–36, thus demonstrating that higher self‐assemblies of the peptide might have an effect on the pharmacokinetics.
Self‐Emergent Protocells Generated in an Aqueous Solution with Binary Macromolecules through Liquid‐Liquid Phase Separation
Authors: Sakuta Hiroki , Fujita Fumika , Hamada Tsutomu , Hayashi Masahito , Takiguchi Kingo , Tsumoto Kanta , Yoshikawa Kenichi
Published: July 2020

Recently, liquid–liquid phase separation (LLPS) has attracted considerable attention among researchers in the life sciences as a plausible mechanism for the generation of microstructures inside cells. LLPS occurs through multiple nonspecific interactions and does not always require a lock‐and‐key interaction with a binary macromolecular solution. The remarkable features of LLPS include the non‐uniform localization and concentration of solutes, resulting in the ability to isolate certain chemical systems and thereby parallelize multiple chemical reactions within the limited space of a living cell. We report that, by using the macromolecules, poly(ethylene glycol) (PEG) and dextran, that exhibit LLPS in an aqueous solution, cell‐sized liposomes are spontaneously formed therein in the presence of phospholipids. In this system, LLPS is generated through the depletion effect of macromolecules. The results showed that cell‐like microdroplets entrapping DNA wrapped by a phospholipid layer emerge in a self‐organized manner.
Unresectable cutaneous metastatic tumor in the arm that underwent complete remission after radiotherapy
Authors: Oike Takahiro , Adachi Akiko , Shirai Katsuyuki , Ohno Tatsuya
Published: July 2020

Cutaneous metastasis of solid malignancies can cause severe disfigurement, which reduces quality of life (QOL). This case indicates potential utility of photon radiotherapy for this disease, leading to recovery of QOL.
Heterochiral DNA with Complementary Strands with α‐d and β‐d Configurations: Hydrogen‐Bonded and Silver‐Mediated Base Pairs with Impact of 7‐Deazapurines Replacing Purines
Authors: Chai Yingying , Guo Xiurong , Leonard Peter , Seela Frank
Published: July 2020

Heterochiral DNA with hydrogen‐bonded and silver‐mediated base pairs have been constructed using complementary strands with nucleosides with α‐d or β‐d configuration. Anomeric phosphoramidites were employed to assemble the oligonucleotides. According to the Tm values and thermodynamic data, the duplex stability of the heterochiral duplexes was similar to that of homochiral DNA, but mismatch discrimination was better in heterochiral DNA. Replacement of purines by 7‐deazapurines resulted in stable parallel duplexes, thereby confirming Watson–Crick‐type base pairing. When cytosine was facing cytosine, thymine or adenine residues, duplex DNA formed silver‐mediated base pairs in the presence of silver ions. Although the CD spectra of single strands with α‐d configuration display mirror‐like shapes to those with the β‐d configuration, the CD spectra of the hydrogen‐bonded duplexes and those with a limited number of silver pairs show a B‐type double helix almost indistinguishable from natural DNA. Nonmelting silver ion–DNA complexes with entirely different CD spectra were generated when the number of silver ions was equal to the number of base pairs.
Trifluoromethylation of [AuF3(SIMes)]: Preparation and Characterization of [Au(CF3)xF3−x(SIMes)] (x=1–3) Complexes
Authors: Winter Marlon , Limberg Niklas , Ellwanger Mathias A. , Pérez‐Bitrián Alberto , Sonnenberg Karsten , Steinhauer Simon , Riedel Sebastian
Published: July 2020

Trifluoromethylation of [AuF3(SIMes)] with the Ruppert–Prakash reagent TMSCF3 in the presence of CsF yields the product series [Au(CF3)xF3−x(SIMes)] (x=1–3). The degree of trifluoromethylation is solvent dependent and the ratio of the species can be controlled by varying the stoichiometry of the reaction, as evidenced from the 19F NMR spectra of the corresponding reaction mixtures. The molecular structures in the solid state of trans‐[Au(CF3)F2(SIMes)] and [Au(CF3)3(SIMes)] are presented, together with a selective route for the synthesis of the latter complex. Correlation of the calculated SIMes affinity with the carbene carbon chemical shift in the 13C NMR spectrum reveals that trans‐[Au(CF3)F2(SIMes)] and [Au(CF3)3(SIMes)] nicely follow the trend in Lewis acidities of related organo gold(III) complexes. Furthermore, a new correlation between the Au−Ccarbene bond length of the molecular structure in the solid state and the chemical shift of the carbene carbon in the 13C NMR spectrum is presented.
Ce‐Doped Ordered Mesoporous Cobalt Ferrite Phosphides as Robust Catalysts for Water Oxidation
Authors: Huang Yarong , Li Menggang , Yang Weiwei , Yu Yongsheng , Hao Sue
Published: July 2020

Controllable synthesis and rational design of ordered nanostructures are crucial for their renewable energy applications. In this work, a mesoporous CoP/Fe2P doped with 5 % Ce by a simple nanocasting method is designed as a superior electrocatalyst for the oxygen evolution reaction (OER). The well‐designed composite delivers an efficient electrocatalytic activity with a low overpotential of 250 mV at 10 mA cm−2 and excellent long‐term stability with no degradation after 10 h of electrochemical OER test, superior to that of the state‐of‐the‐art RuO2 electrocatalyst in alkaline electrolyte. A comprehensive analysis demonstrates that the outstanding OER performance is due to the desirable combination of the highly exposed active centers in the Ce‐doped bimetallic phosphides, efficient mass transfer, and effective electron conduction owing to the hierarchically mesoporous hybridization. Furthermore, the synergistic effect between Ce and CoP/Fe2P accelerates the migration rate of electrons/ions and increases the electrochemical active area. This excellent OER performance observed by Ce doping of CoP/Fe2P makes them possible candidates toward OER in alkaline electrolytes.
Electrophilicity Scale of Activated Amides: 17O NMR and 15N NMR Chemical Shifts of Acyclic Twisted Amides in N−C(O) Cross‐Coupling
Authors: Ielo Laura , Pace Vittorio , Holzer Wolfgang , Rahman Md. Mahbubur , Meng Guangrong , Szostak Roman , Szostak Michal
Published: July 2020

The structure and properties of amides are of tremendous interest in organic synthesis and biochemistry. Traditional amides are planar and the carbonyl group non‐electrophilic due to nN→π*C=O conjugation. In this study, we report electrophilicity scale by exploiting 17O NMR and 15N NMR chemical shifts of acyclic twisted and destabilized acyclic amides that have recently received major attention as precursors in N‐C(O) cross‐coupling by selective oxidative addition as well as precursors in electrophilic activation of N‐C(O) bonds. Most crucially, we demonstrate that acyclic twisted amides feature electrophilicity of the carbonyl group that ranges between that of acid anhydrides and acid chlorides. Furthermore, a wide range of electrophilic amides is possible with gradually varying carbonyl electrophilicity by steric and electronic tuning of amide bond properties. Overall, the study quantifies for the first time that steric and electronic destabilization of the amide bond in common acyclic amides renders the amide bond as electrophilic as acid anhydrides and chlorides. These findings should have major implications on the fundamental properties of amide bonds.
Structural Transformation of the 2‐(p‐Aminophenyl)‐1‐hydroxyinden‐3‐ylmethyl Chromophore as a Photoremovable Protecting Group
Authors: Sasaki Miyu , Tran Bao Nguyen Linh , Yabumoto Sohshi , Nakagawa Tatsuo , Abe Manabu
Published: July 2020

Photoremovable protecting groups (PPGs) have attracted much attention not only in the field of organic synthesis but also in biology and materials science because of the spatiotemporally controlled release of various functional molecules upon photolysis. In this study, a new PPG, the 2‐(p‐aminophenyl)‐1‐hydroxyinden‐3‐ylmethyl (pAPHi) chromophore, is designed and synthesized for the efficient and fast release of functional molecules with high conversion yields. The photolysis of caged benzoic acid with the pAPHi chromophore in dimethyl sulfoxide released benzoic acid in 96 % yield, with a decomposition quantum yield of 13 %. A high quantum yield of 51 % was observed with the clean formation of benzoic acid (94 % yield) in methanol. Transient absorption spectroscopic analyses clarified the generation of an intermediate carbocation as well as its reactivity.
Charge‐Transfer Kinetics of The Solid‐Electrolyte Interphase on Li4Ti5O12Thin‐Film Electrodes
Authors: Nasara Ralph Nicolai , Ma Wen , Kondo Yasuyuki , Miyazaki Kohei , Miyahara Yuto , Fukutsuka Tomokazu , Lin Che‐an , Lin Shih‐kang , Abe Takeshi
Published: July 2020

Charge‐transfer kinetics between electrodes and electrolytes critically determines the performance of lithium‐ion batteries (LIBs). Lithium titanate defect spinel (Li4Ti5O12, LTO) is a safe and durable anode material, but its relatively low energy density limits the range of applications. Utilizing the low potential region of LTO is a straightforward strategy for increasing energy density. However, the electrochemical characteristics of LTO at low potentials and the properties of the solid‐electrolyte interphase (SEI) on LTO are not well understood. Here, we investigate the charge‐transfer kinetics of the SEI formed between model LTO thin‐film electrodes and organic electrolytes with distinct solvation ability using AC impedance spectroscopy whereas their stability was assessed by cyclic voltammetry of ferrocene. With the SEI film on LTO, the Li+desolvation was rate‐determining step but with larger activation energies, which showed a strong dependence on the solvation ability of electrolyte. The activation energies of desolvation for the fluoroethylene carbonate+dimethyl carbonate‐ and ethylene carbonate+diethyl carbonate‐based systems increased from 35 and 55 to 44 and 67 kJ mol−1, respectively, and that for the propylene carbonate‐based system did not noticeably change at around 67 kJ mol−1. In addition, the SEI passivation of LTO was much slower than that of graphite, and the rate also strongly depended on the solvation ability of the electrolyte. Understanding the surface properties of LTO at low potentials opens the door for high‐energy‐density LTO‐based LIBs.
Aromatic Ester‐Functionalized Ionic Liquid for Highly Efficient CO2 Electrochemical Reduction to Oxalic Acid
Authors: Yang Yingliang , Gao Hongshuai , Feng Jiaqi , Zeng Shaojuan , Liu Lei , Liu Licheng , Ren Baozeng , Li Tao , Zhang Suojiang , Zhang Xiangping
Published: July 2020

Electrochemical reduction of CO2 into valuable chemicals is a significant route to utilize CO2 resources. Among various electroreduction products, oxalic acid (H2C2O4) is an important chemical for pharmaceuticals, rare earth extraction, and metal processing. Here, an aprotic aromatic ester‐functionalized ionic liquid (IL), 4‐(methoxycarbonyl) phenol tetraethylammonium ([TEA][4‐MF‐PhO]), was designed as an electrolyte for CO2 electroreduction into oxalic acid. It exhibited a large oxalic acid partial current density of 9.03 mA cm−2 with a faradaic efficiency (FE) of 86 % at −2.6 V (vs. Ag/Ag+), and the oxalic acid formation rate was as high as 168.4 μmol cm−2 h−1, which is the highest reported value to date. Moreover, the results of density functional theory calculations demonstrated that CO2 was efficiently activated to a −COOH intermediate by bis‐active sites of the aromatic ester anion via the formation of a [4‐MF‐PhO‐COOH]− adduct, which finally dimerized into oxalic acid.
Coupling 0D and 1D Carbons for Electrochemical Hydrogen Production Promoted by a Percolation Mechanism
Authors: Dou Zhi , Du Na , Liu Xue , Wu Qiuhua , Wu Qiong , Fu Yang , Zhang Guolin , Ma Tianyi
Published: July 2020

Developing hydrogen evolution reaction (HER) electrocatalysts with high activity, durability and moderate price is essential for sustainable hydrogen energy utilization. Here, the facile coupling of carbon dots (CDs, 0D carbon materials) and carbon fibres (CFs, 1D carbon materials) for enhanced electrochemical hydrogen production was demonstrated. Electrochemical tests revealed that the CD/CF catalysts showed outstanding catalytic activity with a small overpotential of 280 mV at the current density of 10 mA cm−2, a small Tafel slope of 87 mV dec−1 and prominent durability. Percolation theory was for the first time introduced to interpret the catalytic mechanism of the CD/CF catalysts. The special morphology assembled by the 0D carbons constituted the percolating clusters and promoted electron transport throughout the 1D carbons. The strategy and theory can be adapted to general electrocatalytic applications for achieving and interpreting precise tuning on highly efficient electron transfer in electrocatalysts.
Trimetallic MOF‐74 Films Grown on Ni Foam as Bifunctional Electrocatalysts for Overall Water Splitting
Authors: Zhou Weide , Xue Ziqian , Liu Qinglin , Li Yinle , Hu Jianqiang , Li Guangqin
Published: July 2020

Developing earth‐abundant and high‐performance electrocatalysts for water splitting has long been a vital research in energy conversion field. Herein, we report the preparation of a series of trimetallic uniform MnxFeyNi‐MOF‐74 films in‐situ grown on nickel foam, which can be utilized as bifunctional electrocatalysts towards overall water splitting in alkaline media. The introduction of Mn can simultaneously regulate the morphology of MOF‐74 to form uniform film and modulate electronic structure of Fe to form more Fe(II)−O−Fe(III) motifs, which is conducive to the exposure of active sites and stabilizing high‐valent metal sites. The optimized Mn0.52Fe0.71Ni‐MOF‐74 film electrode showed excellent electrocatalytic performance, affording a current density of 10 mA ⋅ cm−2 at an overpotential of 99 mV for HER and 100 mA ⋅ cm−2 at an overpotential of 267 mV for OER, respectively. Assembled as an electrolyser, Mn0.52Fe0.71Ni‐MOF‐74 film electrode exhibited excellent performance towards overall water splitting, with ultralow overpotential of 245 and 462 mV to achieve current density of 10 and 100 mA ⋅ cm−2, respectively. This work provides a new view to develop multi‐metal MOF‐based electrocatalysts.
Nucleophilic Thiols Reductively Cleave Ether Linkages in Lignin Model Polymers and Lignin
Authors: Klinger Grace E. , Zhou Yuting , Foote Juliet A. , Wester Abby M. , Cui Yanbin , Alherech Manar , Stahl Shannon S. , Jackson James E. , Hegg Eric L.
Published: July 2020

Lignin may serve as a renewable feedstock for the production of chemicals and fuels if mild, scalable processes for its depolymerization can be devised. The use of small organic thiols represents a bioinspired strategy to cleave the β‐O‐4 bond, the most common linkage in lignin. In the present study, synthetic β‐O‐4 linked polymers were treated with organic thiols, yielding up to 90 % cleaved monomer products. Lignin extracted from poplar was also treated with organic thiols resulting in molecular weight reductions as high as 65 % (Mn) in oxidized lignin. Thiol‐based cleavage of other lignin linkages was also explored in small‐molecule model systems to uncover additional potential pathways by which thiols might depolymerize lignin. The success of thiol‐mediated cleavage on model dimers, polymers, and biomass‐derived lignin illustrates the potential utility of small redox‐active molecules to penetrate complex polymer matrices for depolymerization and subsequent valorization of lignin into fuels and chemicals.
A Self‐Assembled CO2 Reduction Electrocatalyst: Posy‐Bouquet‐Shaped Gold‐Polyaniline Core‐Shell Nanocomposite
Authors: Vijayakumar Amruthalakshmi , Zhao Yong , Zou Jinshuo , Wang Kezhong , Lee Chong‐Yong , MacFarlane Douglas R. , Wang Caiyun , Wallace Gordon G.
Published: July 2020

Here it was demonstrated that the decoration of gold (Au) with polyaniline is an effective approach in increasing its electrocatalytic reduction of CO2 to CO. The core‐shell‐structured gold‐polyaniline (Au−PANI) nanocomposite delivered a CO2‐to‐CO conversion efficiency of 85 % with a high current density of 11.6 mA cm−2. The polyaniline shell facilitated CO2 adsorption, and the subsequent formation of reaction intermediates on the gold core contributed to the high efficiency observed.
Controlling the Reaction Networks for Efficient Conversion of Glucose into 5‐Hydroxymethylfurfural
Authors: Zhu Liangfang , Fu Xing , Hu Yexin , Hu Changwei
Published: July 2020

Biomass‐derived hexose constitutes the main component of lignocellulosic biomass for producing value‐added chemicals and biofuels. However, the reaction network of hexose is complicated, which makes the highly selective synthesis of one particular product challenging in biorefinery. This Review focuses on the selective production of 5‐hydroxymethylfurfural (HMF) from glucose on account of its potential significance as an important platform molecule. The complex reaction network involved in glucose‐to‐HMF transformations is briefly summarized. Special emphasis is placed on analyzing the complexities of feedstocks, intermediates, (side‐) products, catalysts, solvents, and their impacts on the reaction network. The strategies and representative examples for adjusting the reaction pathway toward HMF by developing multifunctional catalysts and promoters, taking advantage of solvent effects and process intensification, and synergizing all measures are comprehensively discussed. An outlook is provided to highlight the challenges and opportunities faced in this promising field. It is expected to provide guidance to design practical catalytic processes for advancing HMF biorefinery.
Heterogeneous Nature of Electrocatalytic CO/CO2 Reduction by Cobalt Phthalocyanines
Authors: Wu Yueshen , Hu Gongfang , Rooney Conor L. , Brudvig Gary W. , Wang Hailiang
Published: July 2020

Molecular catalysts for electrochemical CO2 reduction have traditionally been studied in their dissolved states. However, the heterogenization of molecular catalysts has the potential to deliver much higher reaction rates and enable the reduction of CO2 by more than two electrons. In light of the recently discovered reactivity of heterogenized cobalt phthalocyanine molecules to catalyze CO2 reduction into methanol, direct comparison is needed to uncover the distinct catalytic activity and selectivity in homogeneous catalysis versus heterogeneous catalysis. Herein, soluble cobalt phthalocyanine derivatives were synthesized, and their catalytic activities in the homogeneous solutions were evaluated. The results show that the observed catalytic activities for both CO2‐to‐CO and CO‐to‐methanol conversions in aqueous solutions of the cobalt phthalocyanines are predominantly heterogeneous in nature through the adsorbed species on the electrode.
Water Oxidation at Neutral pH using a Highly Active Copper‐Based Electrocatalyst
Authors: Younus Hussein A. , Zhang Yan , Vandichel Matthias , Ahmad Nazir , Laasonen Kari , Verpoort Francis , Zhang Ce , Zhang Shiguo
Published: July 2020

The sluggish kinetics of the oxygen evolution reaction (OER) at the anode severely limit hydrogen production at the cathode in water splitting systems. Although electrocatalytic systems based on cheap and earth‐abundant copper catalysts have shown promise for water oxidation under basic conditions, only very few examples with high overpotential can be operated under acidic or neutral conditions, even though hydrogen evolution in the latter case is much easier. This work presents an efficient and robust Cu‐based molecular catalyst, which self‐assembles as a periodic film from its precursors under aqueous conditions on the surface of a glassy carbon electrode. This film catalyzes the OER under neutral conditions with impressively low overpotential. In controlled potential electrolysis, a stable catalytic current of 1.0 mA cm−2 can be achieved at only 2.0 V (vs. RHE) and no significant decrease in the catalytic current is observed even after prolonged bulk electrolysis. The catalyst displays first‐order kinetics and a single site mechanism for water oxidation with a TOF (kcat) of 0.6 s−1. DFT calculations on of the periodic Cu(TCA)2 (HTCA=1‐mesityl‐1H‐1,2,3‐triazole‐4‐carboxylic acid) film reveal that TCA defects within the film create CuI active sites that provide a low overpotential route for OER, which involves CuI, CuII−OH, CuIII=O and CuII−OOH intermediates and is enabled at a potential of 1.54 V (vs. RHE), requiring an overpotential of 0.31 V. This corresponds well with an overpotential of approximately 0.29 V obtained experimentally for the grown catalytic film after 100 CV cycles at pH 6. However, to reach a higher current density of 1 mA cm−2, an overpotential of 0.72 V is required.