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, Artur Laski, Anneke Brümmer, Adam Pruška, Verena Schlösser, Antoine Cléry, Frédéric H.-T. Allain, , Sven Bergmann,
Journal of the American Chemical Society; https://doi.org/10.1021/jacs.1c05214

Abstract:
It is well-accepted that gene expression is heavily influenced by RNA structure. For instance, stem-loops and G-quadruplexes (rG4s) are dynamic motifs in mRNAs that influence gene expression. Adenosine-to-inosine (A-to-I) editing is a common chemical modification of RNA which introduces a nucleobase that is iso-structural with guanine, thereby changing RNA base-pairing properties. Here, we provide biophysical, chemical, and biological evidence that A-to-I exchange can activate latent rG4s by filling incomplete G-quartets with inosine. We demonstrate the formation of inosine-containing rG4s (GI-quadruplexes) in vitro and verify their activity in cells. GI-quadruplexes adopt parallel topologies, stabilized by potassium ions. They exhibit moderately reduced thermal stability compared to conventional G-quadruplexes. To study inosine-induced structural changes in a naturally occurring RNA, we use a synthetic approach that enables site-specific inosine incorporation in long RNAs. In summary, RNA GI-quadruplexes are a previously unrecognized structural motif that may contribute to the regulation of gene expression in vivo.
Ya-Min Zheng, Xiao-Bao Huang, Xiao-Meng Meng, Shou-Dong Xu, , ,
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c12684

Abstract:
Considering the abundance of iron and manganese within the Earth’s crust, the cathode O3-NaFe0.5Mn0.5O2 has shown great potential for large-scale energy storage. Following the strategy of introducing specific heteroelements to optimize the structural stability for energy storage, the work has obtained an O3-type NaFe0.4Mn0.49Cu0.1Zr0.01O2 that exhibits enhanced electrochemical performance and air stability. It displays an initial reversible capacity of 147.5 mAh g–1 at 0.1C between 2 and 4.1 V, a capacity retention ratio exceeding 69.6% after 100 cycles at 0.2C, and a discharge capacity of 70.8 mAh g–1 at a high rate of 5C, which is superior to that of O3-NaFe0.5Mn0.5O2. The codoping of Cu/Zr reserves the layered O3 structure and enlarges the interlayer spacing, promoting the diffusion of Na+. In addition, the structural stability and air stability observed by Cu-doping is well maintained via the incorporation of extra Zr favoring a highly reversible phase conversion process. Thus, this work has demonstrated an efficient strategy for developing cobalt/nickel-free high-capacity and air-stable cathodes for sodium-ion batteries.
Published: 14 September 2021
Abstract:
The surface adsorption and aggregation behavior of a mixture of quaternary-ammonium-salt-type amphiphilic monomeric compounds (C4 FSA, C8 FSA, and C4 NTf2) or gemini compounds (C10-2-C4 FSA) and various surfactants (nonionic hexaoxyethylene dodecyl ether (C12EO6), anionic sodium dodecyl sulfate (SDS), cationic dodecyltrimethylammonium bromide (C12TAB), and zwitterionic N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (C12Sb)) was investigated. Both types of compounds contained alkyl chains of nonidentical lengths that used bis(fluorosulfonyl)imide (FSA–) or bis(trifluoromethanesulfonyl)imide (NTf2–) as counterions. The mixtures were analyzed for surface tension, viscosity, electrical conductivity, and pyrene fluorescence, in addition to evaluation by cryogenic transmission electron microscopy, small-angle X-ray scattering, and dynamic light scattering. Our results showed that the surface tension depended on the surfactant structure. For the mixture of C8 FSA and SDS, as the SDS concentration increased, the surface tension first decreased and became constant at the critical micelle concentration (CMC). In this concentration range, C8 FSA and SDS were approximately equimolar (2.5 mmol dm–3), the mixture adsorbed efficiently at the air–water interface, and vesicles and linear-type micelles were formed in the solution owing to the decreased electrostatic repulsion between the hydrophilic groups. As the SDS concentration further increased, the surface tension increased and reached another constant value. The C8 FSA at the interface was replaced by SDS and the aggregates transformed into spherical micelles. The surface tension plot of the mixture of the amphiphilic compounds and C12Sb showed a minimum at the CMC. The lowest CMC and surface tension were observed for C10-2-C4 FSA, indicating that the gemini compounds offer excellent adsorption and orientation at the air–water interface. It was revealed that the quaternary-ammonium-salt-type amphiphilic compounds in this study acted as ionic liquids on their own and as surfactants in aqueous solution. Further, they could improve the surface activity of conventional ionic surfactants.
Guichao Liu, , Yuechi Hao, Zhifang Feng, Ruiyuan Hu, , Yu-Lan Meng,
ACS Applied Energy Materials; https://doi.org/10.1021/acsaem.1c01662

Abstract:
Herein, an effective electrochemical activation strategy is designed to enhance the overall energy storage performance of copper-based (Cu-based) nickel–cobalt hydroxide (NiCo–OH). The long-term cyclic voltammetry (CV) cycling process in an alkaline electrolyte triggered the in situ transformation from Cu-doped NiCo–OH (Cu/NiCo–OH) to electrochemically activated CuO-doped NiCo–OH (EA-CuO/NiCo–OH) on a porous Cu foam (CF) substrate, together with the significantly increased charge storage capacity. Benefiting from fast electron/ion transfer, abundant surface defects, and powerful synergistic effect contributed by the unique self-supported heterostructure, the EA-CuO/NiCo–OH electrode can achieve a high areal capacity of 4.186 C cm–2 under 5 mA cm–2, with excellent rate performance (67.5% of initial capacity under 50 mA cm–2) and long life span (84.8% of initial capacity after 5000 cycles). The as-fabricated EA-CuO/NiCo–OH//AC hybrid supercapacitor device shows a maximum energy density of 0.648 mW h cm–2 and an outstanding cycling stability (93.4% of initial capacity after 8000 cycles). The superior energy storage performance underpins the high potential of the reported electrochemical activation strategy for developing advanced Cu-based and bimetallic hydroxide-derived electrode materials.
Jianhua Lin, , Minghui Tao, Jun Ma, Liqin Fan, Ren-An Xu, Chunyu Fang
ACS Earth and Space Chemistry; https://doi.org/10.1021/acsearthspacechem.1c00251

Abstract:
Lockdown due to the novel coronavirus disease 2019 (COVID-19) pandemic offers a unique opportunity to study the factors governing the variation in air pollution. A number of studies have investigated the cause underlying the occurrence of heavy haze pollution around the world during the lockdown period. However, information about spatiotemporal variations in gaseous pollutants and detailed quantifications of potential meteorological (METRO) impacts are limited. Ground measurements show that carbon monoxide (CO) pollution deteriorated in northern China despite strict control of human and industrial activities during the lockdown period in early 2020. In this study, a four-dimensional decomposition model was used to quantitatively extract the METRO impacts on the CO pollution over China. The results show that weakened winds elevated CO concentrations near Beijing and in northeastern China. Increased temperatures slightly elevated CO concentrations in northern and eastern China but reduced CO concentrations in northwestern China. Remarkable amounts of CO increases in northern China (e.g., by 0.21 mg/m3 within Beijing) were explained by anomalously high humidity, which could be associated with an enhanced interaction between aerosol and the boundary layer. After excluding the METRO impacts, the CO concentrations drastically declined across China (e.g., by 0.22 mg/m3 within Beijing), indicating that the lockdown indeed greatly lessened CO concentrations. However, the adverse METRO conditions counteracted the beneficial outcomes of emission reductions, leading to a deterioration of the CO pollution in northern China. These results indicate that the METRO factors can play a critical role in worsening air pollution despite a strict control of anthropogenic emissions.
Wenwei Lin, Wen-Ti Guo, Liquan Yao, , Limei Lin, , Shuiyuan Chen,
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c12501

Abstract:
Hydrothermal deposition is emerging as a highly potential route for antimony-based solar cells, in which the Sb2(S,Se)3 is typically in situ grown on a common toxic CdS buffer layer. The narrow band gap of CdS causes a considerable absorption in the short-wavelength region and then lowers the current density of the device. Herein, TiO2 is first evaluated as an alternative Cd-free buffer layer for hydrothermally derived Sb2S3 solar cells. But it suffers from a severely inhomogeneous Sb2S3 coverage, which is effectively eliminated by inserting a Zn(O,S) layer. The surface atom of sulfur in Zn(O,S) uniquely provides a chemical bridge to enable the quasi-epitaxial deposition of Sb2S3 thin film, confirming by both morphology and binding energy analysis using DFT. Then the results of the first-principles calculations also show that Zn(O,S)/Sb2S3 has a more stable structure than TiO2/Sb2S3. The resultant perfect Zn(O,S)/Sb2S3 junction, with a suitable band alignment and excellent interface contact, delivers a remarkably enhanced JSC and VOC for Sb2S3 solar cells. The device efficiency with the TiO2/Zn(O,S) buffer layer boosts from 0.54% to 3.70% compared with the counterpart of TiO2, which has a champion efficiency of Cd-free Sb2S3 solar cells with a structure of ITO/TiO2/Zn(O,S)/Sb2S3/Carbon/Ag by in situ hydrothermal deposition. This work provides a guideline for the hydrothermal deposition of antimony-based films upon a nontoxic buffer layer.
Jin Yang, Xilang Jin, Zhao Cheng, , Lanning Gao, Danlie Jiang, Xile Jie, Yiting Ma, Weixing Chen
ACS Sustainable Chemistry & Engineering; https://doi.org/10.1021/acssuschemeng.1c03868

Abstract:
Devising novel water-soluble carbon dots (CDs) with a facile and economical process is pivotal for the detection of ions in the environment. In this paper, novel nanoscale CDs (polyethyleneimine-2,4-dihydroxybenzoic acid (PEI-DA)) with water solubility and bifunctional detection were synthesized from hyperbranched polyethyleneimine (hPEI) and 2,4-dihydroxybenzoic acid (DA) via a hydrothermal reaction and further self-assembly. PEI-DA exhibited a good linear relationship with Cu2+ or ClO– in the range of 0–30 μM, and its detection limit was determined to be 193 nM (Cu2+) or 478 nM (ClO–). Meanwhile, PEI-DA presented excellent hypotoxicity and biocompatibility in living cells (HeLa cells). On the basis of extraordinary fluorescence properties, PEI-DA-doped solid sensors (test strips and nanofibrous films) were successfully employed to monitor targets sensitively. More importantly, the fluorescence hydrogel was further constructed to rapidly respond to targets (Cu2+ and ClO–), and it could effectively remove Cu2+ in aqueous solution through adsorption ability. In summary, these simple sensing techniques could be implemented as effective tools to monitor Cu2+ and ClO– in environmental and biological samples.
Jian Zhang, Cheng Zhang, Ting Zhu, Yonggao Yan, , Xinfeng Tang
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c12533

Abstract:
The Cu2Se compound possesses extraordinary thermoelectric performance at high temperatures and shows great potential for the application of waste heat recycling. However, a thermoelectric device usually undergoes mechanical vibration, mechanical and/or thermal cycling, and thermal shock in service. Therefore, mechanical properties are of equal importance as thermoelectric performance. However, the mechanical performance and stability of the Cu2Se compound during long-term service at high temperatures have rarely been reported. In this study, we systematically investigated the mechanical properties of Cu2Se compounds synthesized by three varied methods (melting (M), self-propagating high-temperature synthesis (SHS), and a combination of SHS and ultrasonic treatment (UT)) and investigated the thermal stability of the SHS-UT compound under different annealing temperatures. The SHS-UT process effectively refines the grain size from 19 μm for the melting sample to 5 μm for the SHS-UT sample. The high density of grain boundaries in the SHS-UT sample effectively dissipates the energy of crack propagation; thus, the mechanical properties are greatly improved. The compressive strength, bending strength, and Vickers hardness of the SHS-UT sample are 147 MPa, 52.6 MPa, and 0.46 GPa, respectively, which are 21.5, 16.6, and 35.3% higher than those of the melting sample, respectively. Moreover, excellent thermal stability is achieved in the compound prepared by SHS and ultrasonication at a temperature below 873 K. After annealing at temperatures up to 873 K for 7 days, the excellent thermoelectric performance of the Cu2Se compound is well maintained with a ZT value exceeding 1.80 at 873 K. However, with further increasing the annealing temperature to 973 K, the volatilization of Se and the precipitation of Cu result in the instability and significantly deteriorated thermoelectric performance of the material. This work provides an avenue for boosting the mechanical properties and commercial application of Cu2Se.
Published: 14 September 2021
Abstract:
Hexagonal boron nitride (h-BN) is a material with excellent thermal conductivity and electrical insulation, used as an additive to various matrices. To increase the affinity of h-BN to them, hydrogen bonds should be formed at the interface. In reality, however, they are not formed; the N atoms are not capable of accepting hydrogen bonds due to the delocalization of their lone pair electrons over the B–N π bonds. To make it form hydrogen bonds, one may need to break the planarity of h-BN so that the orbital overlap in the B–N π bonds can be reduced. This idea is verified with first-principles calculations on the adsorption of a water molecule on hypothetical h-BN surfaces, the planarity of which is broken. One can do it in silico but not in vitro. BN nanotubes (BNNTs) are considered as a more realistic BN surface with nonplanarity. The hydrogen bond is shown to become stronger as the curvature of the tube increases. On the contrary, the strength of the dispersion force acting at the interface becomes weaker. In water adsorption, these two interactions are in competition with each other. However, in epoxy adhesion, the interaction due to dispersion forces is overwhelmingly stronger than that due to hydrogen bonding. The smaller the curvature of the surface, the smaller the distance between more atoms at the interface; thus, the interaction due to dispersion forces maximized.
Swati J. N. Dixit, Ankur A. Awasthi, , , Neeraj Agarwal
The Journal of Physical Chemistry C; https://doi.org/10.1021/acs.jpcc.1c05709

Abstract:
The correlation between molecular structure and its photophysics is well reported, and organic chemistry is blessed with the freedom of substitution to obtain the desired photophysical property, suitable to control the functional aspects of materials. Despite the fact that the photodynamics of perylene has been studied in depth, its bay and peri aryl-substituted derivatives have not been studied to that extent. Herein, the ultrafast photodynamics of two anisyl perylene derivatives (peri-OCH3 and bay-OCH3) is presented. Isomers of anisyl perylene were designed to study the positional effect of substitution on their molecular packing and excited-state photophysics. The fluorescence spectra of nanoaggregates of peri-OCH3 showed excimer formation, while monomer emission is dominated in bay-OCH3. These features are consistent with the solid-state α-phase and β-phase of perylene, respectively, which are grown in a very precise and controlled manner. Excited-state dynamics studies show that in peri-OCH3, the monomeric free excitons undergo a relatively faster decay to populate the self-trapped monomeric excitonic state and E-state. In bay-OCH3, the contribution of emission from the Y-state and E-state is much less. The molecular structure alteration and different packing are also observed to have an impact on the exciton diffusion rate. The bay-OCH3 isomer is observed to have an almost-double diffusion length, which is attributed to the slightly faster diffusion and longer lifetime of free excitons. The present report indicates the structural modulation effect on the exciton-to-excimer transition dynamics and exciton diffusion properties, which can be beneficial in designing perylene-based materials for organic electronics.
Sellan Premkumar, Zhouzheng Jin, Dan Liu, Devaraj Nataraj, , Alex T. Kuvarega,
ACS Applied Nano Materials; https://doi.org/10.1021/acsanm.1c02371

Abstract:
Improving charge transport properties between the quantum dots (QDs) and reducing the non-radiative recombination have been attempted on silver bismuth iodide (Ag2BiI5) perovskite QDs using oleylamine–sulfide passivation. Herein, we have prepared Ag2BiI5 silver bismuth iodide QDs via a simple ligand-assisted reprecipitation method, and the samples were passivated with the oleylamine–sulfide complex. The absorption and emission profiles were red-shifted, which implies that the overall size of the QDs has increased after the passivation. An increase in the emission intensity confirmed the reduction of non-radiative recombination and an increase in excited-state carrier lifetime, as observed from the time-correlated single-photon counting-lifetime measurements. Further, the photocurrent devices were fabricated and generated high-magnitude photocurrent values in the ranges of ∼1.1 to 1.8 μA (bare Ag2BiI5) and ∼0.27 to 0.54 μA (oleylamine–sulfide-passivated Ag2BiI5) for the biasing voltages of 0.1 and 0.2 V, respectively. Surprisingly, the oleylamine–sulfide-passivated Ag2BiI5 sample exhibited a sharp rise in the photocurrent value with a high on/off ratio. In addition, the bare and oleylamine–sulfide-passivated QDs were further applied for the fluorescence detection of copper Cu(II) ions in drinking water samples for the first time.
Wei Zhou, Priyapan Posri, Xiao-Jing Liu, Zhiran Ju, Wen-Jian Lan,
Journal of Natural Products; https://doi.org/10.1021/acs.jnatprod.1c00152

Abstract:
The soil bacterium Streptomyces pactum ATCC 27456 produces a number of polyketide natural products. Among them is NFAT-133, an inhibitor of the nuclear factor of activated T cells (NFAT) that suppresses interleukin-2 (IL-2) expression and T cell proliferation. Biosynthetic gene inactivation in the ATCC 27456 strain revealed the ability of this strain to produce other polyketide compounds including analogues of NFAT-133. Consequently, seven new derivatives of NFAT-133, TM-129–TM-135, together with a known compound, panowamycin A, were isolated from the culture broth of S. pactum ATCC 27456 ΔptmTDQ. Their chemical structures were elucidated on the basis of their HRESIMS, 1D and 2D NMR spectroscopy, and ECD calculation and spectral data. NFAT-133, TM-132, TM-135, and panowamycin A showed no antibacterial activity or cytotoxicity, but weakly reduced the production of LPS-induced nitric oxide in RAW264.7 cells in a dose-dependent manner. A revised chemical structure of panowamycin A and proposed modes of formation of the new NFAT-133 analogues are also presented.
Published: 14 September 2021
Abstract:
A new coupling reaction, the para-fluoro-thiol (PFT) reaction, activated by base at room temperature, is reported for carbon surface functionalization. 4-Nitrothiophenol (4-NTP) and (3-nitrobenzyl)mercaptan (3-NBM) were coupled to pentafluorophenyl (F5-Ph) anchor layers grafted from the aryldiazonium ion formed in situ. The relative yields of the PFT reactions, estimated from the electrochemical responses of coupled nitrophenyl (NP) and nitrobenzyl (NB) groups, depended on the nucleophilicity of the thiolate and the strength of the base. The highest surface concentration (4.6 × 10–10 mol cm–2) was obtained using 3-NBM in the presence of [Bu4N]OH; this concentration corresponds to the maximum that is typically achieved for other high-yielding coupling reactions at aryldiazonium ion anchor layers. The PFT reaction is expected to be applicable to the numerous thiol derivatives commonly restricted to self-assembled monolayer (SAM) formation at gold and other noble metals, thereby opening a simple new approach for interface design on carbon substrates. The strategy may also have advantages for modification of gold surfaces: the layer prepared by coupling 3-NBM to F5-Ph films on gold was found to be more stable to storage under ambient conditions than self-assembled monolayers of 3-NBM.
Irina V. Novikova, , Chen Du, Marcelina Parra, Doo Nam Kim, Zachary L. VanAernum, Jared B. Shaw, Hanjo Hellmann, ,
Abstract:
Pseudoenzymes have emerged as key regulatory elements in all kingdoms of life despite being catalytically nonactive. Yet many factors defining why one protein is active while its homologue is inactive remain uncertain. For pseudoenzyme–enzyme pairs, the similarity of both subunits can often hinder conventional characterization approaches. In plants, a pseudoenzyme, PDX1.2, positively regulates vitamin B6 production by association with its active catalytic homologues such as PDX1.3 through an unknown assembly mechanism. Here we used an integrative experimental approach to learn that such pseudoenzyme–enzyme pair associations result in heterocomplexes of variable stoichiometry, which are unexpectedly tunable. We also present the atomic structure of the PDX1.2 pseudoenzyme as well as the population averaged PDX1.2–PDX1.3 pseudoenzyme–enzyme pair. Finally, we dissected hetero-dodecamers of each stoichiometry to understand the arrangement of monomers in the heterocomplexes and identified symmetry-imposed preferences in PDX1.2–PDX1.3 interactions. Our results provide a new model of pseudoenzyme–enzyme interactions and their native heterogeneity.
Teng Yang, Yingshuang Xu, Honghao Lv, Min Wang, Xuejing Cui, Guangbo Liu,
ACS Sustainable Chemistry & Engineering; https://doi.org/10.1021/acssuschemeng.1c05184

Abstract:
Molybdenum oxides have been regarded as promising non-noble metal electrocatalysts for hydrogen evolution reaction (HER) due to their low cost, nontoxicity, and chemical stability. However, promoting the intrinsic catalytic activity of molybdenum oxides is crucial for achieving high HER performance. Herein, we demonstrate that the intrinsic HER activity of Ni-doped molybdenum oxides is triggered via a thermal treatment induced phase engineering strategy. The HER overpotential at 10 mA cm–2 decreases from 493 mV (1 M KOH) and 818 mV (seawater) over Ni-doped molybdenum trioxide (Ni-MoO3) to only 234 and 412 mV over Ni-doped molybdenum dioxide (Ni-MoO2), respectively. Moreover, the electrochemical surface areas (ECSAs)-normalized current density over Ni-MoO2, as compared to Ni-MoO3, is at least a 35-fold increase in alkaline (at −0.2 V vs reversible hydrogen electrode (RHE)) and a 59-fold increase in seawater (at −0.4 V vs RHE), confirming the significantly triggered intrinsic HER activity via engineering orthorhombic MoO3 to monoclinic MoO2. Finally, an assembled Mg/seawater battery with the Ni-MoO2 cathode reveals a peak power density of 6.54 mW cm–2 and a continuous stable discharge for over 24 h. This study offers a facile strategy for promoting the intrinsic HER activity of non-noble metal electrocatalysts.
Qiuling Wu, Tianying Zheng, Stuart L. Simpson, , Rong Chen,
Environmental Science & Technology; https://doi.org/10.1021/acs.est.1c03827

Abstract:
The direct measurement of particulate contaminant bioavailability is a challenging aspect for the environmental risk assessment of contaminated sites. Here, we demonstrated a multi-metal stable-isotope-enriched bioassay to simultaneously measure the bioavailability of Cd, Cu, and Zn in naturally contaminated sediments following differing periods of resuspension treatment. Freshwater filter-feeding clams were pre-labeled with the isotopes 114Cd, 65Cu, and 68Zn to elevate isotope abundances in their tissues and then exposed to metal-contaminated suspended sediments. The assimilation of sediment-associated metals by clams would decrease the isotope ratios (Cd114/111, Cu65/63, and Zn68/64) in tissues, providing a direct measurement of metal bioavailability. For the sediments tested here, the method revealed bioavailable cadmium and non-bioavailable copper in sediments but was inconclusive for zinc. With a longer resuspension time, the bioavailability of particulate cadmium increased, but that of copper was unaffected. Metal bioavailability predicted using traditional wet-chemical extraction methods was inconsistent with these findings. The study indicated that multi-metal stable-isotope-enriched bioassay provides a new tool for directly assessing metal bioavailability in sediments, and this method is amenable for use in in situ assessments.
Nour Mattar, Fabian Hübner, Martin Demleitner, Alexander Brückner, , , Holger Ruckdäschel, Agustín Rios de Anda
ACS Applied Polymer Materials; https://doi.org/10.1021/acsapm.1c00894

Abstract:
In this study, accelerated creep and dynamic fatigue crack propagation (FCP) measurements were carried out on fully bio-based epoxy-amine thermoset resins. Formulations based on resorcinol diglycidyl ether (RE) were cured with an aliphatic (hexamethylenediamine—HMDA), a cycloaliphatic (diamine-limonene—DA-LIM), or an aromatic (diamine-allyl eugenol—DA-AE) structure. Diglycidyl ether of bisphenol A (DGEBA) cured with HMDA served as a petrosourced benchmark. By considering a multiscale experimental approach combining these experiments with time-domain NMR, it was found that for DGEBA/HMDA, RE/DA-LIM, and RE/DA-AE, their aging properties depend on the resin network structure characterized by the chemical and physical cross-link density. It was demonstrated that the three considered fully bio-based matrices showed better aging resistance compared to DGEBA/HMDA. For RE/HMDA, which possesses a lower experimental cross-link density than expected, physical entanglements probed by NMR act as semihard cross-links conferring a more ductile behavior. This leads to RE/HMDA showing comparable aging properties to those of RE/DA-LIM and RE/DA-AE. This work shows that the studied fully bio-based epoxy-amine resins possess remarkable fatigue crack resistance properties and can be considered as potential candidates for functional applications. Finally, the proposed multiscale approach combining macroscopic mechanical studies with molecular time-domain NMR allowed us to soundly deepen the understanding of the structure–property relationship for such functional materials.
, Alena A. Aslandukova, Andrey N. Aslandukov, Timofey Fedotenko, , Konstantin Glazyrin, Vitali B. Prakapenka, Leonid S. Dubrovinsky, Natalia Dubrovinskaia
Published: 14 September 2021
Abstract:
High-pressure nitrogen chemistry has expanded at a formidable rate over the past decade, unveiling the chemical richness of nitrogen. Here, the Zn-N system is investigated in laser-heated diamond anvil cells by synchrotron powder and single-crystal X-ray diffraction, revealing three hitherto unobserved nitrogen compounds: β-Zn3N2, α-ZnN4, and β-ZnN4, formed at 35.0, 63.5, and 81.7 GPa, respectively. Whereas β-Zn3N2 contains the N3– nitride, both ZnN4 solids are found to be composed of polyacetylene-like [N4]∞2– chains. Upon the decompression of β-ZnN4 below 72.7 GPa, a first-order displacive phase transition is observed from β-ZnN4 to α-ZnN4. The α-ZnN4 phase is detected down to 11.0 GPa, at lower pressures decomposing into the known α-Zn3N2 (space group Ia3̅) and N2. The equations of states of β-ZnN4 and α-ZnN4 are also determined, and their bulk moduli are found to be K0 = 126(9) GPa and K0 = 76(12) GPa, respectively. Density functional theory calculations were also performed and provide further insight into the Zn-N system. Moreover, comparing the Mg-N and Zn-N systems underlines the importance of minute chemical differences between metal cations in the resulting synthesized phases.
, , Junping Gu, Ce Zhang, Junfu Lyu,
Published: 14 September 2021
Abstract:
Electrowetting (EW) is an effective method for droplet manipulation in microfluidics. In traditional EW, a conductive droplet is actuated, which spreads on a solid substrate. Recently, we considered an opposite phenomenon of droplet actuation in EW: inducing nonconductive droplet dewetting and detaching from the substrate. An oil/water system is used in which the oil droplet (nonconductive) is actuated on a flat substrate in surrounding water (conductive) by EW. In this work, alternating current (AC) electric fields are applied to EW, and the transient dynamics of droplet dewetting, oscillation, and detachment with the AC signals are investigated. The droplet is not in contact with electrodes, and it dances freely on the substrate. Experiments are performed in a wide range of voltages and AC frequencies. To demonstrate the droplet dynamics, we divide the full process of droplet manipulation into three distinguishable periods, that is, an initiating period, a steady oscillation period, and a detaching condition. Transient droplet dewetting is considered in the initiating period, and we obtain the distribution of the contact line friction factor. In steady oscillation, the oscillation resonance is verified from the oscillating amplitude of the contact line. Different periodical features are found for the droplet dancing at the resonance frequencies and departure from resonance. The droplet is detached at high voltages, and we provide a map for the detachable and nondetachable zones. The voltage is the dominant factor determining the droplet detachment; however, the AC frequency has notable influences on the critical voltage. The detachment is promoted when the AC frequency is within the region of the oscillation resonance (e.g., 20 < f < 75 Hz). In this region, the detaching process is not monotonic but instead, the droplet rebounds by several times before it is completely detached.
Jieli Wei, Fanye Meng, Kwang-Su Park, Hyerin Yim, Julia Velez, Prashasti Kumar, Li Wang, Ling Xie, He Chen, Yudao Shen, et al.
Journal of the American Chemical Society; https://doi.org/10.1021/jacs.1c04841

Abstract:
Proteolysis targeting chimeras (PROTACs) represent a new class of promising therapeutic modalities. PROTACs hijack E3 ligases and the ubiquitin-proteasome system (UPS), leading to selective degradation of the target proteins. However, only a very limited number of E3 ligases have been leveraged to generate effective PROTACs. Herein, we report that the KEAP1 E3 ligase can be harnessed for targeted protein degradation utilizing a highly selective, noncovalent small-molecule KEAP1 binder. We generated a proof-of-concept PROTAC, MS83, by linking the KEAP1 ligand to a BRD4/3/2 binder. MS83 effectively reduces protein levels of BRD4 and BRD3, but not BRD2, in cells in a concentration-, time-, KEAP1- and UPS-dependent manner. Interestingly, MS83 degrades BRD4/3 more durably than the CRBN-recruiting PROTAC dBET1 in MDA-MB-468 cells and selectively degrades BRD4 short isoform over long isoform in MDA-MB-231 cells. It also displays improved antiproliferative activity than dBET1. Overall, our study expands the limited toolbox for targeted protein degradation.
Xiao X. Zhang, John William Young, Leonard J. Foster,
Journal of Proteome Research; https://doi.org/10.1021/acs.jproteome.1c00503

Abstract:
Many soluble proteins interact with membranes to perform important biological functions, including signal transduction, regulation, transport, trafficking, and biogenesis. Despite their importance, these protein–membrane interactions are difficult to characterize due to their often-transient nature as well as phospholipids’ poor solubility in aqueous solution. Here, we employ nanodiscs—small, water-soluble patches of a lipid bilayer encircled with amphipathic scaffold proteins—along with quantitative proteomics to identify lipid-binding proteins in Saccharomyces cerevisiae. Using nanodiscs reconstituted with yeast total lipid extracts or only phosphatidylethanolamine (PE-nanodiscs), we capture several known membrane-interacting proteins, including the Rab GTPases Sec4 and Ypt1, which play key roles in vesicle trafficking. Utilizing PE-nanodiscs enriched with phosphatidic acid (PEPA-nanodiscs), we specifically capture a member of the Hsp40/J-protein family, Caj1, whose function has recently been linked to membrane protein quality control. We show that the Caj1 interaction with liposomes containing PA is modulated by pH and PE lipids and depends on two patches of positively charged residues near the C-terminus of the protein. The protein Caj1 is the first example of an Hsp40/J-domain protein with affinity for membranes and phosphatidic acid lipid specificity. These findings highlight the utility of combining proteomics with lipid nanodiscs to identify and characterize protein–lipid interactions that may not be evident using other methods. Data are available via ProteomeXchange with the identifier PXD027992.
Journal of Chemical Theory and Computation; https://doi.org/10.1021/acs.jctc.1c00518

Abstract:
Molecular dynamics simulations are performed for a test set of 20 aprotic ionic liquids to investigate whether including an explicit polarizability model in the force field leads to higher accuracy and reliability of the calculated phase behavior properties, especially the enthalpy of fusion. A classical nonpolarizable all-atom optimized potentials for liquid simulations (OPLS) force-field model developed by Canongia Lopes and Pádua (CL&P) serves as a reference level of theory. Polarizability is included either in the form of Drude oscillators, resulting in the CL&P-D models, or in the framework of the atomic multipole optimized energetics for biomolecular application (AMOEBA) force field with polarizable atomic sites. Benchmarking of the calculated fusion enthalpy values against the experimental data reveals that overall the nonpolarizable CL&P model and polarizable CL&P-D models perform similarly with average deviations of about 30%. However, fusion enthalpies from the CL&P-D models exhibit a stronger correlation with their experimental counterparts. The least successful predictions are interestingly obtained from AMOEBA (deviation ca. 60%), which may indicate that a reparametrization of this force-field model is needed to achieve improved predictions of the fusion enthalpy. In general, all FF models tend to underestimate the fusion enthalpies. In addition, quantum chemical calculations are used to compute the electronic cohesive energies of the crystalline phases of the ionic liquids and of the interaction energies within the ion pair. Significant positive correlations are found between the fusion enthalpy and the cohesive energies. The character of the present anions predetermines the magnitude of individual mechanistic components of the interaction energy and related enthalpic and cohesive properties.
Xiang Chen, , Li Wang, Di Shen, Chengjiang Li, Weibin Zhou
ACS Biomaterials Science & Engineering; https://doi.org/10.1021/acsbiomaterials.1c01073

Abstract:
To simplify the preparation process of a glucose-responsive microneedle patch, a cross-linking-density changeable microneedle patch was designed. The microneedle patch was made up of a hydrogel formed by phenylboronic acid-grafted polyallylamine and poly(vinyl alcohol) (PVA). The gel was cross-linked by boronate ester bonds between phenylboronic acid groups and PVA. It still had fluidity and could be filled into a mold to prepare microneedle patches. Moreover, insulin could be directly loaded into the microneedle patch by mixing with the gel. The boronate ester bond would be broken in the presence of glucose, resulting in a decrease in the cross-linking density. Therefore, the gel could achieve a greater swelling degree and insulin could be released faster. In addition, PVA chains were crystallized by repeatedly freezing and thawing to improve the mechanical strength of the microneedle patch. In terms of glucose-dependent insulin release, the gel showed good glucose-responsive insulin-release ability. Through additional ion cross-linking, the microneedle patch could also control the insulin release according to glucose concentration. In the hypoglycemic experiment of diabetic rats, the microneedle patch effectively pierced the skin and slowly released insulin.
, Xu Yang, Wang Chen, Zili Feng, Chingyuan Hu, Fei Yan, Xiaohua Chen, Dong Qu, Zhiyuan Chen
Published: 14 September 2021
Abstract:
The silver nanoparticles (AgNPs) using the rhizome extract of Rhodiola rosea have been reported. However, their antioxidant activity and whether the biogenic AgNPs could be used to catalyze the reduction of hazardous dye or used as fluorescence enhancers are unknown. This study focused on the facile green synthesis of silver nanoparticles using the rhizome aqueous extract of R. rosea (G-AgNPs). We then studied their antioxidant activity and catalytic degradation of hazardous dye Direct Orange 26 (DO26) and Direct Blue 15 (DB15). Their effects on fluorescein’s fluorescent properties were also evaluated. The chemical AgNPs (C-AgNPs) were synthesized by reducing solid sodium borohydride (NaBH4), and its above activities were compared with those of G-AgNPs. The formation of G-AgNPs was confirmed by the appearance of brownish-gray color and the surface plasmon resonance (SPR) peak at 437 nm. The biogenic AgNPs were approximately 10 nm in size with a regular spherical shape identified from transmission electron microscopy (TEM) analysis. G-AgNPs exhibited significantly improved 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity than butylated hydroxytoluene (BHT) and C-AgNPs (p < 0.05). The biogenic G-AgNPs were also found to function as an effective green catalyst in reducing DO26 and DB15 by NaBH4, which is superior to C-AgNPs. Furthermore, G-AgNPs showed better fluorescence enhancement activity than C-AgNPs, and the concentration required was lower. When the concentration of the G-AgNP solution was 64 nmol/L, the fluorescence intensity reached the maximum of 5460, with the fluorescence enhancement efficiency of 3.39, and the fluorescence activity was stable within 48 h. This study shows the efficacy of biogenic AgNPs in catalyzing the reduction of hazardous dye DO26 and DB15. Biogenic AgNPs could also be used as fluorescence enhancers in low concentrations.
Eisuke Fujiwara, , Daniel Alonso Cerrón-Infantes, Michael Josef Taublaender, ,
Published: 14 September 2021
Abstract:
This study discusses the lattice deformation with an increase in the pressure or temperature of a rigid-rod aromatic polyimide (PI), poly(p-phenylene pyromellitimide), which was enhanced with an increase in the weight density of the lattice. This unique behavior is caused by the suppression of lattice deformation, by means of “misfit strain”, which is induced by the mismatch of the interchain distances between the crystalline and noncrystalline domains. For lattice compression under hydrostatic pressure, the interchain compression was suppressed with a decrease in the crystallinity and/or an increase in the number of PI chains penetrating the interfaces between the crystalline and noncrystalline domains, which is caused by an enhancement of the misfit strain in the crystalline lattice. In contrast, the lattice strain along the main-chain direction (c axis) increased with an increase in the volume fraction of the compressible space near the PI chain ends included in the crystalline domain. Moreover, the thermal expansion of the crystalline lattice was inversely related to the lattice compression, and the coefficient of volumetric expansion increased with an increase in the volumetric compressibility. Accordingly, these results show that the compression and thermal expansion behaviors of the crystalline lattice of the PI are mainly determined by the higher-order structures at the mesoscopic scales, such as the crystallinity and segregated structures between the crystalline and noncrystalline domains, rather than by the crystalline lattice density.
Zongde Jiang, Zisheng Han, Chunyin Qin, Guoping Lai, Mingchun Wen, Chi-Tang Ho, , Xiaochun Wan
Journal of Agricultural and Food Chemistry; https://doi.org/10.1021/acs.jafc.1c03771

Abstract:
During tea processing, roasting significantly affects the transformation pathway of catechins. When (−)-epigallocatechin gallate (EGCG) and glucose were roasted at different pH values, the degree of degradation and isomerization of EGCG was the lowest at pH 7 and the highest at pH 8. Thirty-five products were found in the model reaction of EGCG and glucose under high temperatures, of which four EGCG–glucose adducts were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR). In addition, catechins, gallic acid, and theanine in tea with added glucose were significantly reduced during roasting. The contents of four EGCG–glucose adducts were increased significantly at 150 °C after 30 min and dropped gradually after 60 min. Therefore, based on the present study, EGCG could form crosslinks with glucose under high temperatures in a short time, which provides insight for tea processing and synthesis of catechin–sugar adducts.
Yuanzhe He, , Kai Yang, Xi Wang, Weibin Rong, Lining Sun
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c13551

Abstract:
Cooperative controls of magnetic microswimmers are desired for complex micromanipulation and microassembly tasks. Self-assembled magnetic micropaddles as microswimmers that can locomote freely and cooperate at liquid surfaces are proposed inspired by the paddling motion. The micropaddles are self-assembled with metallic disks under a rotating magnetic field, and they are endowed with controlled propulsion in the precessing field. The micropaddles can locomote freely with a maximum speed of approximately 3.3 mm/s and manipulate objects at the liquid surface. It is found that the micropaddles reverse moving directions at high frequencies and that those with different lengths can locomote in opposite directions under the same precessing magnetic field. Based on the distinctive motion properties, not only could several micropaddles combine into the longer ones but a single micropaddle could also be disassembled into two cooperative partners. Assemblies of different parts based on their cooperation are realized in this study, which is challenging for other types of magnetic microswimmers. Micropaddles with adjustable length, flexible locomotion, and cooperative capability present a promising avenue for various micromanipulation applications.
Alfred T. D’Agostino
Journal of Chemical Education; https://doi.org/10.1021/acs.jchemed.1c00285

Abstract:
Symbolic, spatial, and visual information, which is important for comprehending and learning physical and natural sciences, is not readily accessible to blind and low-vision (BLV) students in the undergraduate chemistry classroom, laboratory, and virtual environment via conventional means (through print and images), thus, creating a disadvantageous and inequitable situation. Appropriate instruction methods can be used to include these differently abled students in the learning process while also enhancing the learning outcomes of a diverse student population. By considering the teaching approach and universal design practices, and utilizing adapted methods, collaborative learning, and nonvisual assistive technologies and equipment, chemistry classroom/laboratory work for BLV students can be transformed from a passive experience to an active one. By creating the least restrictive learning environment, BLV students are enabled to become independent workers. Nonvisual ways (i.e., auditory, and text-to-speech applications, speech-enabled equipment, tactile graphics, and physical artifacts) by which BLV students can conduct their work are described, and practical ways for faculty to enhance teaching are presented.
, Ang Cao, Jens K. Nørskov
Published: 14 September 2021
ACS Catalysis pp 12052-12057; https://doi.org/10.1021/acscatal.1c03094

Abstract:
Ethylene epoxidation is an industrially vital reaction to produce ethylene oxide (EO), which is usually hindered by the competing acetaldehyde formation and the subsequent combustion. So far, Ag-based materials are the most effective catalysts for the reaction, which have been extensively studied over the past decades. However, many fundamental questions are still under debate. In this paper, using density functional theory calculations, scaling relation analysis, and microkinetic modeling, we provide understandings of several open questions for ethylene epoxidation, including why Ag is the best catalyst compared to other group IB metals such as Cu and Au. Our model indicates that the answers to these questions originate from the moderate O-bonding and weak C-bonding strengths on Ag surfaces, leading to relatively high ethylene conversion and EO selectivity.
Ming Zhou, Jiangna Guo, Bo Zhao, Can Li, Lihua Zhang,
Journal of the American Chemical Society; https://doi.org/10.1021/jacs.1c08644

Abstract:
Tuning the crystal phase of bimetallic nanocrystals offers an alternative avenue to improving their electrocatalytic performance. Herein, we present a facile and one-pot synthesis approach that is used to enhance the catalytic activity and stability toward oxygen reduction reaction (ORR) in alkaline media via control of the crystal structure of Pd–Bi nanocrystals. By merely altering the types of Pd precursors under the same conditions, the monoclinic structured Pd5Bi2 and conventional face-centered cubic (fcc) structured Pd3Bi nanocrystals with comparable size and morphology can be precisely synthesized, respectively. Interestingly, the carbon-supported monoclinic Pd5Bi2 nanocrystals exhibit superior ORR activity in alkaline media, delivering a mass activity (MA) as high as 2.05 A/mgPd. After 10,000 cycles of ORR durability test, the monoclinic structured Pd5Bi2/C nanocatalysts still remain a MA of 1.52 A/mgPd, which is 3.6 times, 16.9 times, and 21.7 times as high as those of the fcc Pd3Bi/C counterpart, commercial Pd/C, and Pt/C electrocatalysts, respectively. Moreover, structural characterizations of the monoclinic Pd5Bi2/C nanocrystals after the durability test demonstrate the excellent retention of the original size, morphology, composition, and crystal phase, greatly alleviating the leaching of the Bi component. This work provides new insight for the synthesis of multimetallic catalysts with a metastable phase and demonstrates phase-dependent catalytic performance.
Yue Wu, Yu Wang, ,
Published: 14 September 2021
Abstract:
Both the nonclose-packed structure and the large refractive index contrast of guanine nanocrystals and cytosols in iridophores play a vital role in the dynamic camouflage of chameleons, including the bright skin color and color tuning sensitivity to external stimulus. Here, the nonclose-packed photonic crystals consisting of ZnS nanospheres and polymers, which have similar refractive indices with guanine nanocrystals and cytosols, respectively, are constructed by a two-step filling strategy. [email protected]2 nanospheres are self-assembled to build intermediate close-packed photonic crystals followed by filling polymers in their interstices. The nonclose-packed photonic crystal is successfully achieved when the silica portion is etched by HF solution and refilled by polymers. Excitingly, the stimulus response of the designed photonic crystal is as sensitive as the skin of chameleons due to the similar contrast of refractive indices and nonclose-packed structure. The reflection peak of the structure can blue-shift more than 200 nm as the temperature increases from 30 to 55 °C or under 20% compressional strain. This work not only builds the nonclose-packed photonic crystals by introducing a two-step filling strategy but also proves that high refractive contrast in photonic crystals is an effective strategy to achieve ultrasensitivity, which is highly desirable for various applications.
Noé Fanjul-Mosteirín, , Naroa Sadaba, , Edurne Marin, , Nicolas Ramos-Gomez, , ,
Abstract:
The use of three-dimensional (3D) printable hydrogels for biomedical applications has attracted considerable attention as a consequence of the ability to precisely define the morphology of the printed object, allowing patients’ needs to be targeted. However, the majority of hydrogels do not possess suitable mechanical properties to fulfill an adequate rheological profile for printability, and hence, 3D printing of cross-linked networks is challenging and normally requires postprinting modifications to obtain the desired scaffolds. In this work, we took advantage of the crystallization process of poly(ethylene glycol) to print non-isocyanate poly(hydroxyurethane) hydrogels with tunable mechanical properties. As a consequence of the crystallization process, the hydrogel modulus can be tuned up to 3 orders of magnitude upon heating up to 40 °C, offering an interesting strategy to directly 3D-print hydrogels without the need of postprinting cross-linking. Moreover, the absence of any toxicity makes these materials ideal candidates for biomedical applications.
Tianle Liu, Xiaoqing Wu, Hongquan Xu, Qun Ma, Qiujiao Du, , Pengcheng Gao,
Abstract:
Probe-modified nanopores/nanochannels are one of the most advanced sensors because the probes interact strongly with ions and targets in nanoconfinement and create a sensitive and selective ionic signal. Recently, ionic signals have been demonstrated to be sensitive to the probe–target interaction on the outer surface of nanopores/nanochannels, which can offer more open space for target recognition and signal conversion than nanoconfined cavities. To enhance the ionic signal, we investigated the effect of grafting density, a critical parameter of the sensing interface, of the probe on the outer surface of nanochannels on the change rate of the ionic signal before and after target recognition (β). Electroneutral peptide nucleic acids and negatively charged DNA are selected as probes and targets, respectively. The experimental results showed that when adding the same number of targets, the β value increased with the probe grafting density on the outer surface. A theoretical model with clearly defined physical properties of each probe and target has been established. Numerical simulations suggest that the decrease of the background current and the aggregation of targets at the mouth of nanochannels with increasing probe grafting density contribute to this enhancement. This work reveals the signal mechanism of probe–target recognition on the outer surface of nanochannels and suggests a general approach to the nanochannel/nanopore design leading to sensitivity improvement on the basis of relatively good selectivity.
Ting Wang, Zhijie Chen, Huimin Zhang,
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c11529

Abstract:
To date, it remains a central challenge to achieve electroluminescence in both positive and negative half cycles of alternating-current (AC) voltage for a light-emitting device. Herein, we successfully demonstrated a novel structure to construct a real AC quantum dot light-emitting device (QLED) with two charge generation layers (CGLs) consisting of the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ZnO nanoparticle bilayer structure. Besides the conventional driving way with power input from a pair of opposite electrodes, this AC QLED can also work in the manner of in-planar-electrode driving mode, achieving simultaneous electroluminescence of each pixel. By employing a bilayer emissive layer composed of red and green quantum dots, the emission color of the AC QLED can be tuned by both the polarity and amplitude of the driving voltage. Leveraging the excellent electron injection and negligible voltage consumption from the CGLs, this QLED can be turned on at a record low voltage of 5.6 V. We believe that this AC QLED can provide a platform for the realization of simple and smart plug-and-play QLED-based display and lighting systems.
Nikolai Wurzer, Urszula Klimczak, Tobias Babl, Sebastian Fischer, Ricardo A. Angnes, Dominik Kreutzer, Aryaman Pattanaik, Julia Rehbein,
Published: 14 September 2021
ACS Catalysis pp 12019-12028; https://doi.org/10.1021/acscatal.1c02564

Abstract:
Herein, we report a versatile approach for the endocyclic ring opening of bicyclic vinylcyclopropanes triggered by Heck arylations. The key step for this transformation is a β-C-elimination allowing the ring expansion of cyclopropanated pyrroles, piperidines, furans, as well as cyclopentadienes to grant access to the corresponding 1,2-dihydropyridines, 2H-pyrans, 2,3-dihydro-1H-azepines, and 1,4-cyclohexadienes, respectively. Additionally, gem-disubstituted cyclopropanated furans showed unexpected behavior by giving diastereoselectively asymmetrically substituted dienes. Mechanistic studies and theoretical calculations point toward a facile β-C-elimination with a concomitant shift of Pd along the cyclopropane moiety, which can successfully compete with the usual termination step of a Heck reaction via a syn-β-hydride elimination.
Yiran Ge, Fantian Zeng, Gaofeng Sun, Kewen Peng, Xiao Li, Huijuan Yu, Chao Cheng, , Jian Yang
Abstract:
Aggregation of amyloid β-peptide (Aβ) is closely related to the pathology of Alzheimer’s disease (AD). In this pathology, the beginning stage is characterized by excessive accumulation of Aβ monomers due to imbalanced Aβ in the process of clearance. The Aβ peptide exists in many forms such as soluble and insoluble Aβ species, both of which coexist during the progression of AD and contribute to AD pathology. Thus, probes capable of monitoring all Aβ species are highly desirable. While there are several fluorescent probes for detecting insoluble Aβ, it is still challenging to monitor all Aβ forms by using probes. Here, we describe a near-infrared fluorescent chemical probe, termed AD-1, developed through complexation of curcumin analogues with a stabilizer, which has good photophysical properties and shows high binding to all Aβ species in solution tests. Furthermore, AD-1 exhibited good blood–brain barrier penetrating ability and low cytotoxicity. More importantly, it was successfully applied to 4-month-young APP/PS1 mice imaging noninvasively.
Ritesh Kant Gupta, Rabindranath Garai,
ACS Applied Energy Materials; https://doi.org/10.1021/acsaem.1c01973

Abstract:
Dual-passivation of MAPbI3-based perovskite using p-toluenesulfonic acid (PTSA) in the bulk and hydrophobic polystyrene (PS) at the surface significantly diminishes the trap-density and improves the device performances substantially. The sulfonic acid functional group of PTSA interacts with the defects in perovskite and passivates the trap-states, while PS repairs the surface defects and increases the moisture resistance of perovskites. Thus, improvement in perovskite crystallinity and formation of larger grain size occurs because of dual-passivation, thereby enhancing the power conversion efficiency (PCE) to 20.62% from 15.14% of the device without passivation. Notably, the large-area dual-passivated device also displays a PCE of ∼18.5%. The modified device (PTSA2PS2) showcases reduced hysteresis and a steady-state output of >20%. The PTSA2PS2-based devices exhibit higher photogenerated charges, lower charge recombination, reduced trap-density, and better charge transport than the control devices. The modified device retains 93% of the original PCE after 1000 h under ambient condition.
Qi Yang, , Yuki Kobayashi, Hirotsugu Hiramatsu,
The Journal of Physical Chemistry B; https://doi.org/10.1021/acs.jpcb.1c06058

Abstract:
Stimulation of cells by nanosecond pulsed electric fields (nsPEFs) has attracted attention as a technology for medical applications such as cancer treatment. nsPEFs have been shown to affect intracellular environments without significant damage to cell membranes; however, the mechanism underlying the effect of nsPEFs on cells remains unclear. In this study, we constructed electrodes for applying nsPEFs and analyzed the change in volume of a single cell due to nsPEFs using fluorescence and Raman microscopy. It was shown that the direction of the change depended on the applied electric field; expansion due to the influx of water was observed at high electric field, and cell shrinkage was observed at low electric field. The change in cell volume was correlated to the change in the intracellular Ca2+ concentration, and nsPEFs-induced shrinking was not observed when the Ca2+-free medium was used. This result suggests that the cell shrinkage is related to the regulatory volume decrease where the cell adjusts the increase in intracellular Ca2+ concentration, inducing the efflux of ions and water from the cell.
Gülcihan Gülseren, Aytül Saylam, ,
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c11516

Abstract:
The design of catalysts with greater control over catalytic activity and stability is a major challenge with substantial impact on fundamental chemistry and industrial applications. Due to their unparalleled diversity, selectivity, and efficiency, enzymes are promising models for next-generation catalysts, and considerable efforts have been devoted to incorporating the principles of their mechanisms of action into artificial systems. We report a heretofore undocumented catalyst design that introduces fullerenes to the field of biocatalysis, which we refer to as fullerene nanocatalysts, and that emulates enzymatic active sites through multifunctional self-assembled nanostructures. As a proof-of-concept, we mimicked the reactivity of hydrolases using fullerene nanocatalysts functionalized with the basic components of the parent enzyme with remarkable activity. Owing to the versatile amino acid-based functionalization repertoire of fullerene nanocatalysts, these next-generation carbon/biomolecule hybrids have potential to mimic the activity of other families of enzymes and, therefore, offer new perspectives for the design of biocompatible, high-efficiency artificial nanocatalysts.
Arvin Moser, Alexander E. Waked, Joseph DiMartino
Organic Process Research & Development; https://doi.org/10.1021/acs.oprd.1c00082

Abstract:
We present a perspective on drug development for the synthesis of an active pharmaceutical ingredient (e.g., agomelatine) within a commercial technology called Luminata and compare the results to the current method of consolidating the reaction data into Microsoft Excel. The Excel document becomes the ultimate repository of information extracted from multiple sources such as the electronic lab notebook, the laboratory information management system, the chromatography data system, in-house databases, and external data. The major needs of a pharmaceutical company are tracking the stages of multiple reactions, calculating the impurity carryover across the stages, and performing structure dereplication for an unknown impurity. As there is no standardized software available to link the different needs throughout the life cycle of process development, there is a demand for mapping tools to consolidate the route for an API synthesis and link it with analytical data while reducing transcription errors and maintaining an audit trail.
Chunsong Li, Haocheng Xiong, Ming He, , Qi Lu
Published: 14 September 2021
ACS Catalysis pp 12029-12037; https://doi.org/10.1021/acscatal.1c02852

Abstract:
Ag and Au are efficient monometallic electrocatalysts for the CO2 reduction reaction (CO2RR) to CO. Recent preoxidation treatments on Ag and Au have been shown to effectively improve their reactivity in CO production. However, the mechanism underlying the improvements remains controversial. The challenges in probing the surface speciation under reaction conditions hinder the efforts to be made for correlating the catalyst surface speciation with its performance. Herein, we combine in situ surface-enhanced Raman spectroscopy and reactivity measurements to investigate the coelectrolysis of CO2 and O2 demonstrating that the in-situ-formed surface oxyhydroxyl species on Ag can significantly enhance the CO production rate (>80 fold). In contrast, no surface oxyhydroxyl species was observed on Au in coelectrolysis with O2, which was accompanied by much less significant enhancement in the CO activity (<3-fold). Our work highlights the impact of catalyst surface speciation on the CO2RR performance and opens up a promising route for designing efficient CO2RR catalysts. We believe the findings presented in our work point out a fruitful strategy to design an advanced catalyst and reaction scheme to achieve efficient CO2RR.
Xiaoyan Li, Shuyu Shi, Hang Zhou, Zuoquan Zhao, Jie Lu
Abstract:
To develop novel norepinephrine transporter (NET)-targeting positron emission tomography (PET) probes with optimal pharmacokinetic properties, a series of meta-bromobenzylguanidine derivatives was synthesized. 4-Fluorodiethoxyethane-3-bromobenzylguanidine (compound 12) showed relatively good affinity for the NET (IC50 = 1.00 ± 0.04 μM). The corresponding radiotracer 18F-12 was prepared in high radiochemical purity (>98%) via a three-step method. The in vitro cellular uptake results demonstrated that 18F-12 was specifically taken up by NET-expressing SK-N-SH cells by the uptake-1 mechanism. Biodistribution studies in mice showed that 18F-12 exhibited high cardiac uptake (10.45 ± 0.66 %ID/g at 5 min p.i. and 6.44 ± 0.40 %ID/g at 120 min p.i.), faster liver clearance, and a lower dose of absorbed radiation than [123I]-labeled meta-iodobenzylguanidine ([123I]MIBG). Small animal PET imaging confirmed the high heart-to-background ratio of 18F-12 and the uptake-1 mechanism specific for the NET in rats, indicating its potential as a promising PET radiotracer for cardiac sympathetic nerve imaging.
, Saghir Ahmad
ACS Food Science & Technology; https://doi.org/10.1021/acsfoodscitech.1c00235

Abstract:
The huge amount of banana byproducts produced has posed a serious concern in the present times; however, they contain a plethora of valuable nutrients, antimicrobials, and natural antioxidants. Among these, antioxidants are well-known for the prevention of deteriorative oxidative reactions during processing and storage that cause undesirable quality impairment in foods. Moreover, the harmful effects of synthetic antioxidants (both in vitro and in vivo studies) have compelled the urgency to replace them with alternative natural ones, particularly in the meat industries. Hence, the prime focus of this review is to explore the underexplored sources of antioxidants with health benefits that serve as a replacement for their toxic counterparts (synthetic ones). Antioxidant and antimicrobial activities of banana peel are linked to the phenolics present, furnishing various health benefits. Nevertheless, the literature suggests a rise in research using banana peel in foods, for meat products in particular, as antimicrobial agents.
Zhiwei Li, Jian Zhang, Jianbo Jin, Fan Yang, Rashed Aleisa,
Journal of the American Chemical Society; https://doi.org/10.1021/jacs.1c07241

Abstract:
Conventional colloidal syntheses typically produce nanostructures with positive curvatures due to thermodynamic preference. Here, we demonstrate the creation of surface concavity in Au nanorods through seed-mediated growth in confined spaces and report their thermochromic responses to temperature changes. The unique surface concavity is created by templating against Fe3O4 nanorods, producing a new concavity-sensitive plasmonic band. Due to the high surface energy, the metastable nanorods can be reconstructed at a moderate temperature, enabling convenient and precise tuning of their plasmonic properties by aging in different solvents. Such structural reconstruction of concave Au nanorods enables the fabrication of thermochromic plasmonic films that can display images with vivid color changes or exhibit encrypted, invisible information upon aging. This templating strategy is universal in creating concave nanostructures, which may open the door to designing new nanostructures with promising applications in sensing, anticounterfeiting, information encryption, and displays.
Matthew N. Creyer, Zhicheng Jin, , Wonjun Yim, Jiajing Zhou,
ACS Applied Materials & Interfaces; https://doi.org/10.1021/acsami.1c11620

Abstract:
Gold nanorods possess optical properties that are tunable and highly sensitive to variations in their aspect ratio (length/width). Therefore, the development of a sensing platform where the gold nanorod morphology (i.e., aspect ratio) is modulated in response to an analyte holds promise in achieving ultralow detection limits. Here, we use a dithiol peptide as an enzyme substrate during nanorod growth. The sensing mechanism is enabled by the substrate design, where the dithiol peptide contains an enzyme cleavage site in-between cysteine amino acids. When cleaved, the peptide dramatically impacts gold nanorod growth and the resulting optical properties. We demonstrate that the optical response can be correlated with enzyme concentration and achieve a 45 pM limit of detection. Furthermore, we extend this sensing platform to colorimetrically detect tumor-associated inhibitors in a biologically relevant medium. Overall, these results present a subnanomolar method to detect proteases that are critical biomarkers found in cancers, infectious diseases, and inflammatory disorders.
Min-Cheol Kim, Namyoung Ahn, Diyi Cheng, Mingjie Xu, So-Yeon Ham, Xiaoqing Pan, Suk Jun Kim, Yanqi Luo, , Darren H. S. Tan, et al.
Published: 14 September 2021
ACS Energy Letters pp 3530-3537; https://doi.org/10.1021/acsenergylett.1c01707

Abstract:
Perovskite solar cells have drawn much attention recently owing to their world-record-setting photovoltaic performances, whereas their practicality is still limited by the structural instability that often arises from ion migration and defect formation. Despite the general understanding that ion instability is a primary cause for degradation, there is no observation of structural transformation at the atomistic scale. Such observation is crucial to understand how instabilities are induced by external perturbations such as illumination or electrical bias, allowing researchers to devise effective strategies to mitigate them. Here, we designed an in situ transmission electron microscopy setup to enable real-time observation of amorphization in perovskite materials under electrical biasing. To reverse the device performance degradation due to such structural changes, the samples were heated at 50 °C and were found to recrystallize, effectively regaining their performance losses. This work presents vital insights on understanding ion-migration phenomena and addressing instability challenges of perovskite optoelectronics.
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