bluuebunny/crossref_metadata_2025 huggingface dataset:
Power Quality
Authors: Bollen Math , de Oliveira Roger Alves
Published: February 2023

This item starts with a general discussion on power quality, including definitions, terminology, and requirements. It further contains sections on the importance of power quality (which in the end all comes down to reducing the likelihood of interference, i.e., equipment not functioning as it should); some of the subjects that have been historically on the agenda within power quality (going back to harmonics and light flicker, which were on the agenda before the term power quality in its modern meaning was used, voltage dips, and several waves of interest for waveform distortion); the main aspects of power quality monitoring (different for variations and events); the most important power quality disturbances (voltage magnitude variations, fast voltage variations, voltage dips, voltage swells, interruptions, harmonics, interharmonics, supraharmonics, and transients) and an overview of power quality regulation (discussed around the regulatory dilemma).
False Data Injection Attacks in Power Systems
Authors: Amir Ameli , Hamed Sarjan
Published: February 2023

Power networks are among the most critical infrastructures of any society, since other infrastructures are dependent on power and energy systems. Recently, there has been a trend toward harnessing Information Technology (IT) in power networks to enhance their performance and improve their consumer centricity. This movement, however, has exposed power systems to cyberattacks. Among various types of cyber intrusions, False Data Injection Attack (FDIA) is the most important one, since it stealthily intercepts the legitimate traffic and/or injects malicious data into the system, thus resulting in severe physical and economic damages. There has been a substantial increase in the number of reported FDIAs in recent years, which indicates the necessity of extensive research on vulnerabilities of power systems to FDIAs, probable attack models, impacts of such intrusions, and the possible preventive and detective measures. On this basis, this article presents a comprehensive review of FDIAs in power networks, with a particular focus on attack targets and adversarial methods. Additionally, it elaborates on various types of FDIAs, their implementation steps and strategies, and the vulnerabilities of various components and schemes to this type of attack. Finally, the it briefly discusses FDIA detection techniques in power grids.
Sources of variation in estimating breeding success of migratory birds from autumn counts
Authors: Jensen Gitte Høj , Johnson Fred A. , Madsen Jesper
Published: February 2023

Understanding drivers of change in population sizes requires estimation of demographic rates such as survival and productivity. In migratory geese, productivity or breeding success is typically assessed at the autumn staging and wintering grounds by observing the number of young versus adults in flocks of geese—also called age counts. Such age counts are, however, likely to be affected by a number of factors as we are compelled to sample from an open population, in which the temporal and spatial age composition can vary due to differential migration, mortality and flocking behaviour.

In this study we seek to provide guidance for the design of age counts, by identifying which factors need to be taken into account when collecting data. Identification of these factors will facilitate a more targeted data collection and enable better conservation and management recommendations. We use the long‐term age count dataset for the Svalbard population of the pink‐footed goose and focus on the following factors: May thaw days on Svalbard, region of sampling, flock size, time and cumulative harvest, calculated as the amount of shot individuals up to each observation of juveniles.

We find that the temporal trend in goose productivity based on raw data will be affected by variation in how (which flock sizes), where (which region) and when (which Julian day) the data have been collected.

The sources of variation in observations of goose productivity confound inference at the population level. Thus, if the goal is to follow changes in annual productivity, pooled totals of age counts are only useful if data are collected following a random design. We recommend adjusting for these effects using a demographic population model, particularly for hunted species where age counts are conducted during the hunting season and where annual population assessment work is used to recommend an optimal harvest strategy and allocation of hunting quotas. These considerations not only apply to geese, but more generally to migratory birds where breeding and non‐breeding segments or age groups partially segregate in time and space in autumn.
Trajectories of physical and relational aggression across early childhood: Relations with peer risk factors
Authors: Perry Kristin J. , Ostrov Jamie M.
Published: February 2023

The goal of the current study was to examine trajectories of relational and physical aggression in early childhood and evaluate peer predictors of these trajectories (i.e., peer rejection, relational victimization, and physical victimization). The study spanned three‐time points (T1 in the spring, T2 in the fall, and T3 in the spring) in early childhood (N = 300; 44.0% girls; Mage = 44.70 months, SD = 4.38; 3.0% African American/Black, 7.6% Asian/Asian American/Pacific Islander, 1.0% Hispanic/Latinx, 11.3% multiracial, 62.1% White, and 15.0% missing/unknown). Observations of peer victimization and teacher report of peer rejection were collected at T1, and teacher report of aggression was collected at all time points. Results from piecewise latent growth models demonstrated that both forms of aggression decreased from T1 to T2 as children entered a new classroom and increased from T2 to T3 as they remained in that classroom. The increase in physical aggression from T2 to T3 was only significant for boys. Peer rejection at T1 emerged as a predictor of both intercepts and slopes from T1 to T2, and physical victimization predicted the physical aggression intercept and physical aggression slope from T1 to T2. Children high on these peer risk variables had higher initial levels of aggression, followed by a greater decrease in aggression from T1 to T2. Results underscore the importance of studying incremental change in aggression in early childhood and suggest that children who experience negative peer treatment have greater fluctuations in aggression over time.
Transformative learning as societal learning
Authors: Formenti Laura , Hoggan‐Kloubert Tetyana
Published: February 2023

The article synthesizes literature relating to the recent development of the theory of transformative learning (TL) and societal changes using three exemplary fields of study: (1) Civic education and democratic transformations, (2) TL for sustainability and ecology, and (3) TL in the context of migration (and especially for refugees). This article contends that in the literature, TL is considered a promising answer to an urgent search for conceptual and practical tools to address the wicked problems of our time. We see, however, also the potential pitfall of TL if used as a buzzword or understood as a comprehensive reeducation program designed from above that ignores human agency and the emotional, relational, and political challenges of transformation.
Partial‐nodes‐based state estimation for state‐saturated complex networks with random mixed couplings under dynamic event‐triggered protocol
Authors: Lin Na , Chen Dongyan , Hu Jun , Jia Chaoqing , Yu Hui
Published: February 2023

The state estimation (SE) problem is addressed for state‐saturated complex networks (CNs) contaminated by the random mixed couplings. Such coupling phenomenon consists of the random inner coupling and the random outer coupling, where the random inner coupling is reflected by multiplicative noise and the random outer coupling is described by random variable obeying uniform distribution. In order to reduce resource waste and calculation cost, the additional auxiliary variable method is employed to construct the dynamic event‐triggered communication condition, which can more effectively represent the change of information demand. Accordingly, a novel partial‐nodes‐based (PNB) estimator is designed in the presence of general nonlinearity and state‐saturated nonlinearity, which can estimate the whole states of network nodes with the aid of the measurement information from partial nodes. The appropriate estimator gain is obtained to ensure that the upper bound of estimation error covariance (UBEEC) is minimized. Moreover, sufficient condition is given to guarantee that the trace of the UBEEC is uniformly bounded. Finally, the numerical example is presented to demonstrate the feasibility and effectiveness of the developed PNB estimation algorithm.
The Sluggish Diffusion of Cations in CeO2 Probed through Molecular Dynamics and Metadynamics Simulations
Authors: Körfer Sylvia , Bonkowski Alexander , Kler Joe , Hatton Peter , Uberuaga Blas Pedro , De Souza Roger A.
Published: February 2023

Cation diffusion in fluorite‐structured CeO2, though far slower than anion diffusion, is an important, high‐temperature process because it governs diverse fabrication and degradation phenomena. Herein, cation diffusion is studied by means of classical molecular dynamics and metadynamics simulations. Three different mechanisms are examined: migration involving an isolated cerium vacancy, migration involving a cerium vacancy in a defect associate with an oxygen vacancy, and migration involving a cation divacancy. For each mechanism, defect diffusion coefficients are calculated as a function of temperature, from which the respective activation enthalpy of defect migration is obtained. Through comparisons with experimental cation diffusion data (specifically, of the absolute magnitude of the cation diffusivity as well as its activation enthalpy), it is concluded that cation diffusion takes place predominantly neither by isolated vacancies nor by cation vacancy–oxygen vacancy associates but by cation divacancies.
Rod‐Shaped Polymeric Nanoparticles Intervene Neutrophils for Efficient Ischemic Stroke Therapy
Authors: Song Zhuolun , Fang Jinghuan , Wang Zhenhua , Xiao Renming , Guo Xing , Zhou Shaobing
Published: February 2023

Neutrophils are associated with pro‐inflammation and contribute to pathophysiology of ischemic stroke. Prevention of neutrophils from infiltrating into ischemic area can be a potential approach for stroke therapy. In this study, a rod‐shaped polylactic acid polyglycolic acid (PLGA) nanoparticles encapsulated with piceatannol is developed to target and intervene the interaction of neutrophils with inflamed endothelial cells. In contrast to macrophages, neutrophils exhibit enhanced endocytosis of elongated particles. The nanoparticles with aspect ratio (AR) of 5 display higher internalization by neutrophils compared to other nanoparticles. Thus, AR5 nanoparticles are screened out to load with piceatannol (Pic@AR5) for investigating the therapeutic effect against middle cerebral artery occlusion model. It is demonstrated that Pic@AR5 can block the adherence of neutrophils to endothelial cells, inhibiting the infiltration of neutrophils into blood‐brain barrier (BBB). Besides, the inflammatory cytokine of ischemic brain can also be reduced even if a small part of Pic@AR5‐carried neutrophils enter BBB. The nanoparticles release piceatannol within the ischemic region, which inhibit microglial Syk signal and result in alleviation of neuroinflammation. This strategy provides new insights into ischemic stroke therapy.
Cordycepin‐Loaded Macrophage Vesicles for Targeted Nonalcoholic Steatohepatitis Attenuation
Authors: Li Xinyue , Fan Yuanyuan , Zha Zhengbao , Gong Deyan , Yu Jiajia , Li Qianhui , Li Ruoyao , Wang Hua , Wang Fei
Published: February 2023

Cordycepin (3′‐deoxyadenosine) has a demonstrated value in ameliorating nonalcoholic steatohepatitis (NASH); however, its short in vivo metabolism time and high dose‐induced cytotoxicity are challenges limiting its clinical application. Herein, a cordycepin‐loaded macrophage vesicle (C‐MV) is developed for targeted cordycepin delivery to achieve stable and durable mitigation of NASH. The C‐MV is obtained using cytochalasin B‐stimulated RAW 264.7 cells to produce MV, followed by repeated freeze‐thawing and extrusion of MV and cordycepin. C‐MV selectively delivers cordycepin to macrophages at the site of liver injury, slowly releases cordycepin, reduces the toxicity associated with high cordycepin doses, and increases the mice's survival rate from 40% to 90%. Moreover, C‐MV reduces liver apoptosis and attenuated NASH liver injury by activating AMP‐activated protein kinase and inhibiting caspase 6 activity. Overall, C‐MV exhibits better anti‐inflammatory, lipid‐lowering, and anti‐apoptosis properties than free cordycepin, making it a promising delivery system for the potential clinical application of cordycepin. MV combined with cordycepin provides an inspiring bionic strategy for NASH treatment that can achieve effective therapeutic effects in vivo.
High‐Quality Femtosecond Laser Surface Micro/Nano‐Structuring Assisted by A Thin Frost Layer
Authors: Gao Wenhai , Zheng Kai , Liao Yang , Du Henglei , Liu Chengpu , Ye Chengrun , Liu Ke , Xie Shaoming , Chen Cong , Chen Junchi , Peng Yujie , Leng Yuxin
Published: February 2023

Femtosecond laser ablation has been demonstrated to be a versatile tool to produce micro/nanoscale features with high precision and accuracy. However, the use of high laser fluence to increase the ablation efficiency usually results in unwanted effects, such as redeposition of debris, formation of recast layer, and heat‐affected zone in or around the ablation craters. Here this limitation is circumvented by exploiting a thin frost layer with a thickness of tens of microns, which can be directly formed by the condensation of water vapor from the air onto the exposed surface whose temperature is below the freezing point. When the femtosecond laser beam is focused onto the target surface covered with a thin frost layer, only the local frost layer around the laser‐irradiated spot melts into water, helping to boost ablation efficiency, suppress the recast layer, and reduce the heat‐affect zone, while the remaining frost layer can prevent ablation debris from adhering to the target surface. By this frost‐assisted strategy, high‐quality surface micro/nano‐structures are successfully achieved on both plane and curved surfaces at high laser fluences, and the mechanism behind the formation of high‐spatial‐frequency (HSF) laser‐induced periodic surface structures (LIPSSs) on silicon is discussed.
Multiple Orbital Angular Momentum Beams with High‐Purity of Transmission‐Coding Metasurface
Authors: Liu Xiaobin , Li Sijia , He Chengyuan , Li Zhuoyue , Huang Guoshuai , Cao Xiangyu
Published: February 2023

Vortex electromagnetic wave carrying orbital angular momentum (OAM) is expected to break through the shortage of spectrum resource because of its multiple independent modes. Nowadays, there are various methods to generate OAM vortex beam. Based on the concepts of digital metasurface and propagation phase, a broadband 3‐bit coding transmission metasurface is designed and illustrated by simulation and measurement. The elements exhibit the different phase by changing the size of metal patch, and the focusing phase is introduced to reduce the divergence of OAM beams. Based on the principle of phase superposition, the wide‐band, high‐purity, and multi‐beam OAM vortex waves can be generated by the transmission‐coding metasurface (TCMS). The experimental results verify that TCMS realizes the multiple OAM beams along different directions simultaneously from 9 to 10.5 GHz, which are consistent with the theoretical results. The high purity more than 90% of OAM mode is demonstrated by both the simulated and measured results. The TCMS provides a potential and effective scheme for OAM multiplexing and multi‐target positioning in wireless systems.
Analysis of the Electrical ReRAM Device Degradation Induced by Thermal Cross‐Talk
Authors: Al‐Mamun Mohammad , Chakraborty Amrita , Orlowski Marius
Published: February 2023

A switching of resistive memory cells leads to a local accumulation of Joules heat in the device. In resistive RAM (ReRAM) arrays, the heat generated in one cell spreads via common electrode metal lines to the neighboring cells and may cause their performance degradation. The performance degradation results in reduced number of switching cycles and, in extreme cases, even in a loss of a bit, caused by the rupture of the nanofilament. The authors propose a thermal analysis of the thermal cross‐talk, describe its impact on cells’ electric performance, and identify three major mechanisms for the ReRAM reliability: (i) thermal conductivity, (ii) the specific heat capacity, and (iii) geometry of the electrodes. Several ReRAM arrays are manufactured to vary thermal conductivity, specific heat and geometry of the electrodes by depositing eight different inert electrodes: Pt(50 nm)/Ti(30 nm), Ru(50 nm)/Ti(30 nm), Co(50 nm)/Ti(30 nm), Pt(50 nm/Cu(100 nm)/Ti(30 nm), Pt(50 nm)/ Cu(200 nm)/Ti(30 nm), Ru(50 nm/Cr(30 nm), Ru(50 nm)/Ti(50 nm), and Rh(50 nm)/Cr(30 nm). The experimentally found differences of the degradation of electric performance of the array cells performed under identical circumstances can be correctly predicted by the proposed thermal analysis using the material properties and geometry parameters of the electrodes.
Memristive Memory Enhancement by Device Miniaturization for Neuromorphic Computing
Authors: Goossens Anouk S. , Ahmadi Majid , Gupta Divyanshu , Bhaduri Ishitro , Kooi Bart J. , Banerjee Tamalika
Published: February 2023

The areal footprint of memristors is a key consideration in material‐based neuromorphic computing and large‐scale architecture integration. Electronic transport in the most widely investigated memristive devices is mediated by filaments, posing a challenge to their scalability in architecture implementation. Here, a compelling alternative memristive device is presented and it is demonstrated that areal downscaling leads to enhancement in the memristive memory window, while maintaining analog behavior, contrary to expectations. The device designs directly integrated on semiconducting Nb‐doped SrTiO3 (Nb:STO) allows leveraging electric field effects at edges, increasing the dynamic range in smaller devices. The findings are substantiated by studying the microscopic nature of switching using scanning transmission electron microscopy, in different resistive states, revealing an interfacial layer whose physical extent is influenced by applied electric fields. The ability of Nb:STO memristors to satisfy hardware and software requirements with downscaling, while significantly enhancing memristive functionalities, make them strong contenders for non‐von‐Neumann computing, beyond complementary metal–oxide–semiconductor.
Current Status and Future Perspective on Lithium Metal Anode Production Methods
Authors: Acebedo Begoña , Morant‐Miñana Maria C. , Gonzalo Elena , Ruiz de Larramendi Idoia , Villaverde Aitor , Rikarte Jokin , Fallarino Lorenzo
Published: February 2023

Lithium metal batteries (LMBs) are one of the most promising energy storage technologies that would overcome the limitations of current Li‐ion batteries, based on their low density (0.534 g cm−3), low reduction potential (−3.04 V vs Standard Hydrogen Electrode) as well as their high theoretical capacities (3860 mAh g−1 and 2061 mAh cm−3). The overall cell mass and volume would be reduced while both gravimetric and volumetric energy densities would be greatly improved. Their electrochemical performance, however, is hampered by the low efficiency at high current densities and continuous degradation, which are related, among other factors, to the properties of the lithium metal anode (LMA). Hence, the production and processing of LMAs is crucial to obtain the desired properties that would enable LMBs. Here, the conventional method used for the production of LMAs, which is the combination of extraction, electrowinning, extrusion, and rolling processes, is reviewed. Then, the advances in the different alternative methods that can be used to produce and improve the properties of LMAs are described, which are divided into vapor phase, liquid phase, and electrodeposition. Within this last method, the anode‐less concept, for which different approaches to the development of advanced current collectors are illustrated, is included.
Tailoring the Interfacial Termination via Dipole Interlayer for High‐Efficiency Perovskite Solar Cells
Authors: Yang Tengteng , Zhao Wangen , Liu Xin , Liu Shengzhong (Frank)
Published: February 2023

The ionic nature of the organic‐inorganic hybrid perovskite material is prone to react with different functional groups. Here, a series of polar molecules with permanent dipole moments are designed to modify the perovskite surface termination. It is observed that proper interfacial design can significantly reduce trap state density for effective charge transfer. The energy level of the substrate can be adjusted by the magnitude and direction of the dipole moment. As a result, a high 24.54% photo‐electric conversion efficiency is reached by introducing pentafluoride benzene moieties with carboxylic functional groups. In addition, the humidity and heat stability of the perovskite device is obviously improved. This work demonstrates the importance of chemical interactions at perovskite termination and paves the way for further enhancing the performance of perovskite solar cells.
Probabilistic predictions for partial least squares using bootstrap
Authors: Odgers James , Kappatou Chrysoula , Misener Ruth , García Muñoz Salvador , Filippi Sarah
Published: February 2023

Modeling the uncertainty in partial least squares (PLS) is made difficult because of the nonlinear effect of the observed data on the latent space that the method finds. We present an approach, based on bootstrapping, that automatically accounts for these nonlinearities in the parameter uncertainty, allowing us to equally well represent confidence intervals for points lying close to or far away from the latent space. To show the opportunities of this approach, we develop applications in determining the Design Space for industrial processes and model the uncertainty of spectroscopy data. Our results show the benefits of our method for accounting for uncertainty far from the latent space for the purposes of Design Space identification, and match the performance of well established methods for spectroscopy data.
Longitudinal growth of stature in boys according to age and puberty: Prediction of adult stature from the age of 13 years
Authors: Pineau Jean‐Claude
Published: February 2023

Background

The purpose of this study was to cross‐validate and demonstrate how adult stature can be predicted in 13‐year‐old teenager's boys by using a new reference specific growth curve obtained from chronological age and maturity.

Methods

Stature measurements of 125 boys aged from 12 to 17.5 years were obtained over a period of five consecutive years. The maturity was based on the age of peak height velocity (APHV). An assessment of secondary pubertal stages using a simplification of the Tanner stages was also carried out. We found a connection between the secondary pubertal stage and the APHV. We carried out a prediction of the adult stature of 67 teenagers aged from 160 and 164 months.

Results

Significant differences between APHV enabled us to classify the adolescents into three categories according to their biological maturity: 19% of adolescents with advanced puberty, 62% with standard puberty and 19% with delayed puberty. The mean growth curves were used to predict the adult stature of 67 individuals with a good accuracy (±3 cm). The mean differences between predicted and real adult stature are −0.11 cm with 95% limits of agreement of [−3.2; + 2.8 cm].

Conclusions

The new stature growth curves developed from age and maturation enables us to accurately track individual growth kinetics.
What would a population‐level approach to dementia risk reduction look like, and how would it work?
Authors: Walsh Sebastian , Govia Ishtar , Peters Ruth , Richard Edo , Stephan Blossom C.M. , Wilson Nikki‐Anne , Wallace Lindsay , Anstey Kaarin J. , Brayne Carol
Published: February 2023

Dementia is a leading global public health challenge. Prevention approaches have traditionally focused on individual‐level strategies. However, such approaches have limited potential, particularly for resource‐constrained populations in which exposure to risk factors is greatest, and exposure to protective factors is lowest. A population‐level approach to dementia risk reduction is therefore essential to meet the scale of the challenge and to tackle global inequalities in risk and incidence of disease. Such approaches can be highly cost effective. In this viewpoint article, we describe what such an approach should look like, barriers and facilitators to success, and how we should go about achieving it. We include 10 strategic goals to achieve population‐level dementia risk reduction and protection enhancement, targeted at researchers, professionals, funders, science communicators, governments, businesses, and policy makers. If we are to significantly reduce the prevalence of dementia there must be increased emphasis on population‐level approaches.

Highlights

Dementia risk reduction is a global public health priority

Population‐level approaches change societal conditions to make them less conducive to dementia's modifiable risk factors, and increase exposure to protective factors.

Urgent development of population‐level approaches is required to reduce the prevalence of, and inequalities in, dementia

Action is required from researchers, governments and business, funders, public health professionals, and science communicators.
A Simple, Transition Metal Catalyst‐Free Method for the Design of Complex Organic Building Blocks Used to Construct Porous Metal–Organic Frameworks
Authors: Kochetygov Ilia , Roth Jocelyn , Espín Jordi , Pache Sophia , Justin Anita , Schertenleib Till , Taheri Nazanin , Chernyshov Dmitry , Queen Wendy L.
Published: February 2023

The design of metal–organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time‐consuming palladium‐catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (SNAr) reactions, is used for the transition metal catalyst‐free construction of 21 new, carboxylate‐based ligands with varying sizes, shapes, and denticity and 15 linear di‐ and tetra‐nitriles. Moreover, to demonstrate the utility of the ligands as building blocks, 16 new structurally diverse MOFs having surface areas up to 3100 m2 g−1 were also synthesized.
Hydrated Eutectic Electrolytes Stabilizing Quasi‐Underpotential Mg Plating/Stripping for High‐Voltage Mg Batteries
Authors: Liu Guigui , Tang Yongchao , Li Hongqing , He Jiangfeng , Ye Minghui , Zhang Yufei , Wen Zhipeng , Liu Xiaoqing , Li Cheng Chao
Published: February 2023

Aqueous rechargeable Mg batteries (ARMBs) usually fail from severe anode passivation, alternatively, executing quasi‐underpotential Mg plating/stripping chemistry (UPMC) on a proper heterogeneous metal substrate is a crucial remedy. Herein, a stable UPMC on Zn substrate is initially achieved in new hydrated eutectic electrolytes (HEEs), delivering an ultralow UPMC overpotential and high energy/voltage plateau of ARMBs. The unique eutectic property remarkably expands the lower limit of electrochemical stability window (ESW) of HEEs and undermines the competition between hydrogen evolution/corrosion reactions and UPMC, enabling a reversible UPMC. The UPMC is carefully revealed by multiple characterizations, which shows a low overpotential of 50 mV at 0.1 mA cm−2 over 550 h. With sulfonic acid‐doped polyaniline (SPANI) cathodes, UPMC‐based full cells show high energy/power densities of 168.6 Wh kg−1/2.1 kWh kg−1 and voltage plateau of 1.3 V, far overwhelming conventional aqueous systems.
Enhanced Four‐Electron Oxygen Reduction Selectivity of Clamp‐Shaped Cobalt(II) Porphyrin(2.1.2.1) Complexes
Authors: Xue Songlin , Ryan Osterloh W. , Lv Xiaojuan , Liu Ningchao , Gao Yimei , Lei Haitao , Fang Yuanyuan , Sun Zhongti , Mei Peifeng , Kuzuhara Daiki , Aratani Naoki , Yamada Hiroko , Cao Rui , Kadish Karl M. , Qiu Fengxian
Published: February 2023

The molecular structure, electrochemistry, spectroelectrochemistry and electrocatalytic oxygen reduction reaction (ORR) features of two CoII porphyrin(2.1.2.1) complexes bearing Ph or F5Ph groups at the two meso‐positions of the macrocycle are examined. Single crystal X‐ray analysis reveal a highly bent, nonplanar macrocyclic conformation of the complex resulting in clamp‐shaped molecular structures. Cyclic voltammetry paired with UV/Vis spectroelectrochemistry in PhCN/0.1 M TBAP suggest that the first electron addition corresponds to a macrocyclic‐centered reduction while spectral changes observed during the first oxidation are consistent with a metal‐centered CoII/CoIII process. The activity of the clamp‐shaped complexes towards heterogeneous ORR in 0.1 M KOH show selectivity towards the 4e− ORR pathway giving H2O. DFT first‐principle calculations on the porphyrin catalyst indicates a lower overpotential for 4e− ORR as compared to the 2e− pathway, consistent with experimental data.
Expanding the Promiscuity of a Copper‐Dependent Oxidase for Enantioselective Cross‐Coupling of Indoles
Authors: Guo Huan , Sun Ningning , Guo Juan , Zhou Tai‐Ping , Tang Langyu , Zhang Wentao , Deng Yaming , Liao Rong‐Zhen , Wu Yuzhou , Wu Guojiao , Zhong Fangrui
Published: February 2023

Herein, we disclose the highly enantioselective oxidative cross‐coupling of 3‐hydroxyindole esters with various nucleophilic partners as catalyzed by copper efflux oxidase. The biocatalytic transformation delivers functionalized 2,2‐disubstituted indolin‐3‐ones with excellent optical purity (90–99 % ee), which exhibited anticancer activity against MCF‐7 cell lines, as shown by preliminary biological evaluation. Mechanistic studies and molecular docking results suggest the formation of a phenoxyl radical and enantiocontrol facilitated by a suited enzyme chiral pocket. This study is significant with regard to expanding the catalytic repertoire of natural multicopper oxidases as well as enlarging the synthetic toolbox for sustainable asymmetric oxidative coupling.
High‐Porosity Metal‐Organic Framework Glasses
Authors: Xu Wentao , Hanikel Nikita , Lomachenko Kirill A. , Atzori Cesare , Lund Alicia , Lyu Hao , Zhou Zihui , Angell C. Austen , Yaghi Omar M.
Published: February 2023

We report a synthetic strategy to link titanium‐oxo (Ti‐oxo) clusters into metal‐organic framework (MOF) glasses with high porosity though the carboxylate linkage. A new series of MOF glasses was synthesized by evaporation of solution containing Ti‐oxo clusters Ti16O16(OEt)32, linkers, and m‐cresol. The formation of carboxylate linkages between the Ti‐oxo clusters and the carboxylate linkers was confirmed by Fourier‐transform infrared (FT‐IR) spectroscopy. The structural integrity of the Ti‐oxo clusters within the glasses was evidenced by both X‐ray absorption near edge structure (XANES) and 17O magic‐angle spinning (MAS) NMR. After ligand exchange and activation, the fumarate‐linked MOF glass, termed Ti‐Fum, showed a N2 Brunauer–Emmett–Teller (BET) surface areas of 923 m2 g−1, nearly three times as high as the phenolate‐linked MOF glass with the highest BET surface area prior to this report.
Amorphous NiFe Oxide‐based Nanoreactors for Efficient Electrocatalytic Water Oxidation
Authors: Li Xiaojie , Zhang Huike , Hu Qi , Zhou Weiliang , Shao Jiaxin , Jiang Xingxing , Feng Chao , Yang Hengpan , He Chuanxin
Published: February 2023

Synergy engineering is an important way to enhance the kinetic activity of oxygen‐evolution‐reaction (OER) electrocatalysts. Here, we fabricated NiFe amorphous nanoreactor (NiFe‐ANR) oxide as OER electrocatalysts via a mild self‐catalytic reaction. Firstly, the amorphousness helps transform NiFe‐ANR into highly active hydroxyhydroxides, and its many fine‐grain boundaries increase active sites. More importantly, as proved by experiments and finite element analysis, the nanoreactor structure alters the spatial curvature and the mass transfer over the catalyst, thereby enriching OH− in the catalyst surface and inner part. Thus, the catalyst with the structure of amorphous nanoreactors gained excellent activity, far superior to the NiFe catalyst with the structure of crystalline nanoreactor or amorphous non‐nanoreactor. This work provides new insights into the applications and mechanisms of amorphousness and nanoreactors, embodying the “1+1>2” synergy of crystalline state and morphology.
Alternative Fast and Slow Primary Charge‐Separation Pathways in Photosystem II
Authors: Capone Matteo , Sirohiwal Abhishek , Aschi Massimiliano , Pantazis Dimitrios A. , Daidone Isabella
Published: February 2023

Photosystem‐II (PSII) is a multi‐subunit protein complex that harvests sunlight to perform oxygenic photosynthesis. Initial light‐activated charge separation takes place at a reaction centre consisting of four chlorophylls and two pheophytins. Understanding the processes following light excitation remains elusive due to spectral congestion, the ultrafast nature, and multi‐component behaviour of the charge‐separation process. Here, using advanced computational multiscale approaches which take into account the large‐scale configurational flexibility of the system, we identify two possible primary pathways to radical‐pair formation that differ by three orders of magnitude in their kinetics. The fast (short‐range) pathway is dominant, but the existence of an alternative slow (long‐range) charge‐separation pathway hints at the evolution of redundancy that may serve other purposes, adaptive or protective, related to formation of the unique oxidative species that drives water oxidation in PSII.
Pore Aperture Control Toward Size‐Exclusion‐Based Hydrocarbon Separations
Authors: Lal Bhajan , Idrees Karam B. , Xie Haomiao , Smoljan Courtney S. , Shafaie Saman , Islamoglu Timur , Farha Omar K.
Published: February 2023

Metal–organic frameworks (MOFs) have been proposed as a promising material for non‐thermal chemical separations owing to their high structural diversity and tunability. Here, we report the synthesis of a zinc‐based MOF containing a three‐dimensional (3D) linker, bicyclo[2.2.2]octane‐1,4‐dicarboxylic acid, with high thermal stability towards the separation of hexane isomers. The incorporation of the 3D linker enhances the structural stability and provides well‐defined pore apertures/channels with sub‐Ångstrom precision. This precision allowed for the separation of similarly sized hexane isomers based on subtle differences in their kinetic diameters. Multi‐component liquid phase batch experiments confirmed the separation of hexanes mixture into linear, monobranched, and dibranched isomers. This work represents a significant milestone in the construction of stable Zn‐based MOFs and the incorporation of 3D linkers as a potential solution to challenging separations.
Alkyds with artistic applications based on drying oils, multifunctional polyalcohols and different polybasic acids
Authors: Bellatin Arciniega Luciano , Meza Yapu Raúl , Obregón Valencia Daniel , Hadzich Antonella , Costa Marcus A. , Ispas Adriana , Bund Andreas , Flores Santiago
Published: February 2023

Today's requirements in the art field have challenged researchers to create artistic paintings with attractive appearance and long‐term color stability. Alkyd‐based art mediums have become an important group in the art field, because of their similar characteristics to traditional oils and exceptional drying properties. In this work, high solid alkyd‐based art mediums have been synthesized by the monoglyceride and acidolysis processes. Multifunctional polyols and high unsaturated fatty acid sources were compared and used for alkyd synthesis. The use of a non‐traditional oil of Peruvian origin is proposed. Resins have been characterized according to their physicochemical (acid number, viscosity, color and density) and drying properties. Drying tendencies were verified with the use of quartz crystal microbalance. Also, the behavior of the art mediums mixed with commercial oil paintings and a dry pigment, have also been evaluated. Results indicate that resins containing the polyol with the highest functionality are more viscous and have fewer tendencies to yellowing, while non‐traditional Peruvian oil is the best option for creating light‐colored art mediums. Alkyd mediums prepared by the monoglyceride method gave to oil paintings better characteristics and drying behavior on canvas.
Poly (polyethylene glycol diacrylate‐co‐allyl glycidyl ether) cryogels: Preparation, modification with iminodiacetic acid, and application of Cu(II) removal
Authors: Zhu Zhifei , Li Junying , Ma Feng , Chen Guangxu , Tian Haoran , Li Jian , Yang Pengfei
Published: February 2023

In this study, poly (polyethylene glycol diacrylate‐co‐allyl glycidyl ether) cryogels (p(PEGDA‐co‐AGE)) was synthesized by low‐temperature polymerization using polyethylene glycol diacrylate (PEGDA), allyl glycidyl ether (AGE), and N,N′‐methylenebisacrylamide (MBAAm). The cryogel was then modified with iminodiacetic acid (IDA) by a ring‐opening reaction of AGE to attach carboxyl groups on the surface. The modified cryogel (p(PEGDA‐co‐AGE)‐IDA) was characterized by scanning electron microscope, energy dispersive X‐ray spectra, infrared spectra, X‐ray photoelectron spectroscopy, and compression test, as well as its absorption performance. It was found that the adsorption efficiency and the reusability of cryogels for Cu(II) was related to pH, and the maximum adsorption capacity was 76.49 mg g−1 (pH = 6). In addition, the kinetics of Cu(II) adsorption on cryogels was investigated to clarify the adsorption mechanism.
Influence of accelerators and curing system composition on the cure characteristics, crosslinks structure and properties of acrylonitrile‐butadiene elastomer
Authors: Maciejewska Magdalena , Sowińska‐Baranowska Anna
Published: February 2023

The goal of this work is to study the influence of the type of vulcanization accelerator and the quantitative composition of the curing system on the cure characteristics, morphology of elastomer network, crosslink density and physico‐chemical properties of acrylonitrile‐butadiene rubber (NBR) composites. Sulfur curing systems are investigated, which consist of various types of accelerators, that is, sulfenamide, guanidine and thiuram, applied in various proportions to sulfur. The type of accelerator and the sulfur/accelerator ratio significantly affect both the cure rate and the structure and number of crosslinks resulting from the vulcanization. The highest cure rate and the lowest content of polysulfidic crosslinks are exhibited by rubber composites with efficient (EV) curing systems due to the highest content of accelerators compared to semi‐efficient (SEV) and conventional (CV) systems. The structure of crosslinks strongly affect tensile properties and hardness of the vulcanizates as well as their solvent resistance, thermal stability and resistance to thermo‐oxidative aging.
Red‐emissive Dual‐state Fluorogenic Probe for Wash‐free Imaging of Lipid Droplets in Living Cells and Fatty Liver Tissues
Authors: Wang Hui , Zhang Cuifeng , Hu Lei , Tang Fang , Wang Yaxuan , Ding Feiyang , Lu Jingwen , Ding Aixiang
Published: February 2023

Lipid droplet (LD) dysfunction can result in various diseases, such as nonalcoholic fatty liver disease. Imaging agents built on dual‐state emission (DSE) molecules that fluoresce in both dilute solutions and the aggregated state are receiving attention as this type of probe could provide bright fluorescence signals at variable concentrations, avoiding false signal readout caused by the concentration fluctuation in living systems. Herein, we identified a red emissive molecule featuring DSE, from three newly synthesized molecules, for specific detection of LDs in live cells. The bioimaging abilities have been well confirmed by optical spectroscopies, theoretical calculations, cell experiments, as well as animal studies. The DSE probe is effective for LD detection at concentrations ranging from 1 μM to 100 μM while retaining high brightness and signal fidelity. This study provides a knowledge base for the future design of DSE‐active fluorescent probes for understanding LD‐related diseases.
Sample size calculation for the combination test under nonproportional hazards
Authors: Cheng Huan , He Jianghua
Published: February 2023

For sample size calculation in clinical trials with survival endpoints, the logrank test, which is the optimal method under the proportional hazard (PH) assumption, is predominantly used. In reality, the PH assumption may not hold. For example, in immuno‐oncology trials, delayed treatment effects are often expected. The sample size without considering the potential violation of the PH assumption may lead to an underpowered study. In recent years, combination tests such as the maximum weighted logrank test have received great attention because of their robust performance in various hazards scenarios. In this paper, we propose a flexible simulation‐free procedure to calculate the sample size using combination tests. The procedure extends the Lakatos' Markov model and allows for complex situations encountered in a clinical trial, like staggered entry, dropouts, etc. We evaluate the procedure using two maximum weighted logrank tests, one projection‐type test, and three other commonly used tests under various hazards scenarios. The simulation studies show that the proposed method can achieve the target power for all compared tests in most scenarios. The combination tests exhibit robust performance under correct specification and misspecification scenarios and are highly recommended when the hazard‐changing patterns are unknown beforehand. Finally, we demonstrate our method using two clinical trial examples and provide suggestions about the sample size calculations under nonproportional hazards.
Reaction intensification for biocatalytic production of polyphenolic natural product di‐C‐β‐glucosides
Authors: Li Tuo , Borg Annika J. E. , Krammer Leo , Breinbauer Rolf , Nidetzky Bernd
Published: February 2023

Polyphenolic aglycones featuring two sugars individually attached via C‐glycosidic linkage (di‐C‐glycosides) represent a rare class of plant natural products with unique physicochemical properties and biological activities. Natural scarcity of such di‐C‐glycosides limits their use‐inspired exploration as pharmaceutical ingredients. Here, we show a biocatalytic process technology for reaction‐intensified production of the di‐C‐β‐glucosides of two representative phenol substrates, phloretin (a natural flavonoid) and phenyl‐trihydroxyacetophenone (a phenolic synthon for synthesis), from sucrose. The synthesis proceeds via an iterative two‐fold C‐glycosylation of the respective aglycone, supplied as inclusion complex with 2‐hydroxypropyl β‐cyclodextrin for enhanced water solubility of up to 50 mmol/L, catalyzed by a kumquat di‐C‐glycosyltransferase (di‐CGT), and it uses UDP‐Glc provided in situ from sucrose by a soybean sucrose synthase, with catalytic amounts (≤3 mol%) of UDP added. Time course analysis reveals the second C‐glycosylation as rate‐limiting (0.4–0.5 mmol/L/min) for the di‐C‐glucoside production. With internal supply from sucrose keeping the UDP‐Glc at a constant steady‐state concentration (≥50% of the UDP added) during the reaction, the di‐C‐glycosylation is driven to completion (≥95% yield). Contrary to the mono‐C‐glucoside intermediate which is stable, the di‐C‐glucoside requires the addition of reducing agent (10 mmol/L 2‐mercaptoethanol) to prevent its decomposition during the synthesis. Both di‐C‐glucosides are isolated from the reaction mixtures in excellent purity (≥95%), and their expected structures are confirmed by NMR. Collectively, this study demonstrates efficient glycosyltransferase cascade reaction for flexible use in natural product di‐C‐β‐glucoside synthesis from expedient substrates.
etiBsu1209: A comprehensive multiscale metabolic model for Bacillus subtilis
Authors: Bi Xinyu , Cheng Yang , Xu Xianhao , Lv Xueqin , Liu Yanfeng , Li Jianghua , Du Guocheng , Chen Jian , Ledesma‐Amaro Rodrigo , Liu Long
Published: February 2023

Genome‐scale metabolic models (GEMs) have been widely used to guide the computational design of microbial cell factories, and to date, seven GEMs have been reported for Bacillus subtilis, a model gram‐positive microorganism widely used in bioproduction of functional nutraceuticals and food ingredients. However, none of them are widely used because they often lead to erroneous predictions due to their low predictive power and lack of information on regulatory mechanisms. In this work, we constructed a new version of GEM for B. subtilis (iBsu1209), which contains 1209 genes, 1595 metabolites, and 1948 reactions. We applied machine learning to fill gaps, which formed a relatively complete metabolic network able to predict with high accuracy (89.3%) the growth of 1209 mutants under 12 different culture conditions. In addition, we developed a visualization and code‐free software, Model Tool, for multiconstraints model reconstruction and analysis. We used this software to construct etiBsu1209, a multiscale model that integrates enzymatic constraints, thermodynamic constraints, and transcriptional regulatory networks. Furthermore, we used etiBsu1209 to guide a metabolic engineering strategy (knocking out fabI and yfkN genes) for the overproduction of nutraceutical menaquinone‐7, and the titer increased to 153.94 mg/L, 2.2‐times that of the parental strain. To the best of our knowledge, etiBsu1209 is the first comprehensive multiscale model for B. subtilis and can serve as a solid basis for rational computational design of B. subtilis cell factories for bioproduction.
The microRNomes of Chinese hamster ovary (CHO) cells and their extracellular vesicles, and how they respond to osmotic and ammonia stress
Authors: Belliveau Jessica , Papoutsakis Eleftherios T.
Published: February 2023

A new area of focus in Chinese hamster ovary (CHO) biotechnology is the role of small (exosomes) and large (microvesicles or microparticles) extracellular vesicles (EVs). CHO cells in culture exchange large quantities of proteins and RNA through these EVs, yet the content and role of these EVs remain elusive. MicroRNAs (miRs or miRNA) are central to adaptive responses to stress and more broadly to changes in culture conditions. Given that EVs are highly enriched in miRs, and that EVs release large quantities of miRs both in vivo and in vitro, EVs and their miR content likely play an important role in adaptive responses. Here we report the miRNA landscape of CHO cells and their EVs under normal culture conditions and under ammonia and osmotic stress. We show that both cells and EVs are highly enriched in five miRs (among over 600 miRs) that make up about half of their total miR content, and that these highly enriched miRs differ significantly between normal and stress culture conditions. Notable is the high enrichment in miR‐92a and miR‐23a under normal culture conditions, in contrast to the high enrichment in let‐7 family miRs (let‐7c, let‐7b, and let‐7a) under both stress conditions. The latter suggests a preserved stress‐responsive function of the let‐7 miR family, one of the most highly preserved miR families across species, where among other functions, let‐7 miRs regulate core oncogenes, which, depending on the biological context, may tip the balance between cell cycle arrest and apoptosis. While the expected—based on their profound enrichment—important role of these highly enriched miRs remains to be dissected, our data and analysis constitute an important resource for exploring the role of miRs in cell adaptation as well as for synthetic applications.