bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unraveling Sequence Effect on Glass Transition Temperatures of Discrete Unconjugated Oligomers
Authors: Liu Ruizhe , Yang Chao , Huang Zixuan , French Rohan , Gu Zi , Cheng Jianli , Guo Kunkun , Xu Jiangtao 
Published: December 2021

AbstractSequence plays a critical role in enabling unique properties and functions of natural biomolecules, which has promoted the rapid advancement of synthetic sequence‐defined polymers in recent decades. Particularly, investigation of short chain sequence‐defined oligomers (also called discrete oligomers) on their properties has become a hot topic. However, most studies have focused on discrete oligomers with conjugated structures. In contrast, unconjugated oligomers remain relatively underexplored. In this study, three pairs of discrete oligomers with the same composition but different sequence for each pair are employed for investigating their glass transition temperatures (Tgs). The resultant Tgs of sequenced oligomers in each pair are found to be significantly different (up to 11.6 °C), attributable to variations in molecular packing as demonstrated by molecular dynamics and density function theory simulations. Intermolecular interaction is demonstrated to have less impact on Tgs than intramolecular interaction. The mechanistic investigation into two model dimers suggests that monomer sequence caused the difference in intramolecular rotational flexibility of the sequenced oligomers. In addition, despite having different monomer sequence and Tgs, the oligomers have very similar solubility parameters, which supports their potential use as effective oligomeric plasticizers to tune the Tgs of bulk polymer materials.
Interfacial Effect on Dielectric Properties of Self‐Assembled Polythiourea‐Based Copolymers for Ultrahigh Energy Storage
Authors: Feng Yang , Jiang Liuhao , Yang Anqi , Liu Xia , Yang Liuqing , Lu Guanghao , Li Shengtao 
Published: December 2021

AbstractPolymer dielectrics are highly desirable in capacitor applications due to their low cost, high stability, and reliability. However, there still remains a lack of feasible methods to prepare polymer dielectrics with high energy density and low dielectric loss, which severely hampers the development of compact and efficient power electronics. Here, an amphiphilic block copolymer, polythiourea‐b‐polydimethylsiloxane (PTU‐b‐PDMS), with an extraordinarily high energy density of 29.8 J cm−3 and a low loss is synthesized via polyaddition polymerization. This is highly relevant to the block molecule conformation in the interfacial region of the self‐assembled PTU‐b‐PDMS. The block molecule in the interface adopts an extended conformation when the PTU forms nanodots, whereas the block molecule adopts a coiled conformation when the PTU forms nanostrands. The observation and characterization have proved that the coiled block molecule in the interfacial region can simultaneously induce extra strong charge trapping sites and dipolar polarization. It substantially improves the breakdown strength from 652 to 1166 MV m−1, while maintaining a high dielectric constant of 5 and a low loss of <0.01. This work offers unprecedented structural insights into the conformation‐induced interfacial effect and enables rational design of self‐assembled copolymers to boost their dielectric properties and energy density.
Dietary Milk Phospholipids Attenuate Chronic Stress‐Induced Changes in Behavior and Endocrine Responses across the Lifespan
Authors: Schverer Marina , Donoso Francisco , Mitchell Avery , Rea Kieran , Fitzgerald Patrick , Sen Paromita , Roy Bernard L. , Stanton Catherine , Dinan Timothy G. , Cryan John F. , Schellekens Harriët 
Published: December 2021

ScopeIncreasing scientific evidence is validating the use of dietary strategies to support and improve brain health throughout the lifespan, with tailored nutritional interventions catering for specific life stages. Dietary phospholipid supplementations in early life and adulthood are shown to alleviate some of the behavioral consequences associated with chronic stress. This study aims to explore the protective effects of a tailored phospholipid‐enriched buttermilk on behavioral and endocrine responses induced by chronic psychosocial stress in adulthood, and to compare these effects according to the life stage at which the supplementation is started.Methods and ResultsA novel developed phospholipid‐enriched dairy product is assessed for its effects on social, anxiety‐ and depressive‐like behaviors, as well as the stress response and cognitive performance following chronic psychosocial stress in C57BL/6J mice, with supplementation beginning in adulthood or early life. Milk phospholipid supplementation from birth protects adult mice against chronic stress‐induced changes in endocrine response to a subsequent acute stressor and reduces innate anxiety‐like behavior in non‐stressed animals. When starting in adulthood, the dietary intervention reverses the anxiety‐like phenotype caused by chronic stress exposure.ConclusionDairy‐derived phospholipids exert differential protective effects against chronic psychosocial stress depending on the targeted life stage and duration of the dietary supplementation.
Velocity vector reconstruction for real‐time phase‐contrast MRI with radial Maxwell correction
Authors: Kollmeier Jost M. , Kalentev Oleksandr , Klosowski Jakob , Voit Dirk , Frahm Jens 
Published: December 2021

PurposeTo develop an auto‐calibrated image reconstruction for highly accelerated multi‐directional phase‐contrast (PC) MRI that compensates for (1) reconstruction instabilities occurring for phase differences near and (2) phase errors by concomitant magnetic fields that differ for individual radial spokes.Theory and MethodsA model‐based image reconstruction for real‐time PC MRI based on nonlinear inversion is extended to multi‐directional flow by exploiting multiple flow‐encodings for the estimation of velocity vectors. An initial smoothing constraint during iterative optimization is introduced to resolve the ambiguity of the solution space by penalizing phase wraps. Maxwell terms are considered as part of the signal model on a line‐by‐line basis to address phase errors by concomitant magnetic fields. The reconstruction methods are evaluated using simulated data and cross‐sectional imaging of a rotating‐disc, as well as in vivo for the aortic arch and cervical spinal canal at 3T.ResultsReal‐time three‐directional velocity mapping in the aortic arch is achieved at 1.8 × 1.8 × 6 mm3 spatial and 60 ms temporal resolution. Artificial phase wraps are avoided in all cases using the smoothness constraint. Inter‐spoke differences of concomitant magnetic fields are effectively compensated for by the model‐based image reconstruction with integrated radial Maxwell correction.ConclusionVelocity vector reconstructions based on nonlinear inversion allow for high degrees of radial data undersampling paving the way for multi‐directional PC MRI in real time. Whether a spoke‐wise treatment of Maxwell terms is required or a computationally cheaper frame‐wise approach depends on the individual application.
Lead acid battery with high resistance to over‐discharge using graphite based materials as cathode current collector
Authors: Okano Hiroshi , Hano Yuta , Sugimoto Kaito , Ohira Fumiya , Inoue Takashi , Hosokawa Toshihiro , Iwai Taichi , Takai Shigeomi , Yabutsuka Takeshi , Yao Takeshi 
Published: December 2021

AbstractLead acid battery has been one of the most important battery for industry use. However, conventional lead acid battery cannot be recharged after over discharge and the performance is greatly declined. It has been revealed that the cause of not being able to be recharged is the formation of α‐PbO2 on the surface of β‐PbO2 cathode active material due to local cell reaction between lead current collector and β‐PbO2. Formation of α‐PbO2 is prevented by using gold as the current collector. In this study, we developed the lead acid battery with high resistance to over discharge using graphite materials as current collector. The formation of α‐PbO2 was prevented by using expanded natural graphite sheet as cathode current collector. The lead acid battery with current collector of expanded natural graphite sheet containing 5% polypropylene (PP) can repeat deep charge and discharge between 0 and 2 V for more than about 6 months and showed flat potential area between 1.9 and 1.3 V for every cycle. Furthermore, this battery can be charged again after over discharge for more than 4 month at the open circuit. We have succeeded to develop high performance lead acid battery.
Bending the Curve: Molecular Manifestations of Electron Antisymmetry
Authors: Herzfeld Judith , Song Xinrui , Li Jicun , Li Pinyuan 
Published: December 2021

AbstractAs very light fermions, electrons are governed by antisymmetric wave functions that lead to exchange integrals in the evaluation of the energy. Here we use the localized representation of orbitals to decompose the electronic energy in a fashion that isolates the enigmatic exchange contributions and characterizes their distinctive control over electron distributions. The key to this completely general analysis is considering the electrons in groups of three, drawing attention to the curvatures of pair potentials, rather than just their amplitudes and slopes. We show that a positive curvature at short distances is essential for the mutual distancing of electrons and a negative curvature at longer distances is essential to account for the influence of lone pairs on bond torsion. Neither curvature is available in the absence of the exchange contributions. Thus, although exchange energies are much shorter range than Coulomb energies, their influence on molecular geometry is profound and readily understood.
Comparative study of Abaca fiber and Kevlar fibers based brake friction composites
Authors: Kumar Naresh , Kumar Sushil , Grewal Jasmaninder Singh , Mehta Vikas , Ali Sarafat 
Published: December 2021

AbstractWHO and Environment protection agencies have reported that the trending brake pad materials are harmful to human health. These materials (Asbestos and Kevlar) produce toxic gases when used in brake pad composites. It is a cause of lung cancer, mesothelioma, affects the respiratory system, and causes many diseases. It has been causing many million people's death. Kevlar (aramid) is the trending material used in the brake pads. So, it is necessary to find a substitute for these toxic elements. In this direction synthetic fiber has been replaced by natural fiber. The main aim of this study is to find a substitute for asbestos and synthetic fibers (Kevlar) in brake friction material. There are very few comparative studies of Kevlar and natural fiber‐based reinforced polymer composites. In this research Abaca fiber and Kevlar fibers have been reinforced as brake friction material and compared studies. The brake pads were developed by using the various percentages of Abaca fibers (5–20%) and Kevlar fiber (5–10%) with other important ingredients of brake in the hydraulic hind Brake melding Machine. The results of physio‐mechanical properties reveal that % porosity, % water absorption, % compressibility increases as increase the percentage of Abaca fiber and Kevlar fiber in the polymer composite while ash, hardness, and density decrease with an increased percentage of Abaca and Kevlar fiber in the composite matrix. The tensile strength, ultimate compressive strength, impact energy, flexural strength, flexural modulus, tensile modulus shows the best performance for 5% brake pad composites among all Abaca fiber composites and while ultimate shear strength and proof stress show the best performance for 10% brake pad composites among all Abaca mixtures. The Abaca fiber composites with 5 wt% have shown improved results for the coefficient of friction, fade percentage and wear among all‐natural fiber composites while the performance in terms of recovery was observed to increase with an increased percentage of Abaca fiber. In the comparative study it has been found that Kevlar‐based brake pad specimens showed little better results in %‐fade, coefficient of friction, and in wear performance than that of Abaca‐composites while mechanical properties have shown nearby results. The wear rate and thermal stability were recorded highest for 20% Abaca fiber composite and 10% Kevlar composite.
Temperature‐dependent performance of silicon heterojunction solar cells with transition‐metal‐oxide‐based selective contacts
Authors: Le Anh Huy Tuan , Dréon Julie , Michel Jesús Ibarra , Boccard Mathieu , Bullock James , Borojevic Nino , Hameiri Ziv 
Published: December 2021

AbstractThe temperature coefficient (TC) is an essential figure of merit to accurately evaluate solar cell performance at various operating temperatures and hence enabling the comparison between different cell technologies. Recently, solar cells that use passivating contacts based on transition metal oxide (TMO) layers have attracted much attention due to their excellent performance. Therefore, knowledge of their TCs and insights into their performance at various operating temperatures are of significant interest. In this study, we investigate the temperature‐dependent performance of solar cells with TMO‐based passivating contacts at various illumination intensities. We then compare their performance to that of standard silicon heterojunction (SHJ) solar cells. The efficiency TC (TCη) of solar cells that use passivating contacts based on molybdenum oxide (MoOx) and titanium oxide (TiOx) films is found to be almost identical. Both outperform the TCη of the standard SHJ cells and are greatly superior to those of cell structures without passivating contacts. The superior TCη of the MoOx‐based cells is mainly due to their favourable TCs of the short‐circuit current density (TCJsc) and fill factor (TCFF), whereas the superiority of TCη of the TiOx‐based cells is solely resulting from the superior TCFF. The favourable TCJsc of the MoOx‐based cells is explained by an enhanced spectral response at short wavelengths with increasing temperature, due to the improvement of the passivation quality of the MoOx‐based passivating contacts. The beneficial TCFF of both solar cells is partly resulting from the improvement of the contact resistivity of the TMO‐based passivating contacts which counterbalances some of the fill factor losses at elevated temperatures. Although an improvement of the passivation quality of the TMO‐based passivating contacts is observed at elevated temperature, it does not have a strong impact on the TC of the open‐circuit voltage of the investigated solar cells. Furthermore, we also found that the studied cells are less sensitive to temperature variation at higher illumination intensities.
Prioritising crop wild relatives to enhance agricultural resilience in sub‐Saharan Africa under climate change
Authors: Satori David , Tovar Carolina , Faruk Aisyah , Hammond Hunt Eleanor , Muller Gemma , Cockel Christopher , Kühn Nicola , Leitch Ilia J. , Lulekal Ermias , Pereira Laura , Ryan Philippa , Willis Katherine J. , Pironon Samuel 
Published: December 2021

Social Impact StatementClimate change is expected to disproportionately affect sub‐Saharan Africa in the next century, posing a threat to the livelihoods of smallholder farmers and deepening food insecurity. To adapt to this threat, more climate‐resilient crops need to be brought into the food system; these may be developed through breeding with crop wild relatives with key traits to cope with climate change. Here, we assess the level of open‐access trait documentation of crop wild relatives of 29 important crops, their resilience, how threatened they are in situ, how well they are preserved ex situ and we provide priorities for their conservation and use in breeding programmes.Summary

Climate change is projected to adversely affect smallholder agriculture in sub‐Saharan Africa (SSA) over the next century, with many areas becoming unsuitable for growing crops. Breeding programmes using crop wild relatives (CWRs) that are pre‐adapted to projected future climatic conditions may lead to more resilient crops, but their traits have not been screened across a large diversity of CWRs. Furthermore, many are threatened and require greater protection in situ and ex situ to prevent the loss of an important adaptive solution to climate change.
A previous ecogeographical study found that 303 out of 836 CWRs of 29 major crops cultivated across SSA may represent priorities for future crop resilience. Here, we assessed the availability of trait information and compared traits between resilient and non‐resilient CWRs. Subsequently, we analysed the conservation status of CWRs in situ and ex situ to set new global priorities for protection.
Our findings show that the traits of many CWRs are poorly described, but for those species with better coverage, key differences between resilient and non‐resilient CWRs were identified, including lower plant height amongst resilient CWRs of tree crops (arabica and robusta coffee, mango and cacao) and a higher likelihood of invasive CWRs to be resilient. We found that 14% and 36% of resilient CWRs are threatened in situ and absent from seed collections, respectively.
Our study highlights CWR priorities for conservation based on resilience. A concerted international effort is recommended to conserve CWRs and improve agricultural resilience in a changing climate.
Algebraic and complexity‐like properties of Jacobi polynomials: Degree and parameter asymptotics
Authors: Sobrino Nahual , S.‐Dehesa Jesus 
Published: December 2021

AbstractThe Jacobi polynomials conform the canonical family of hypergeometric orthogonal polynomials (HOPs) with the two‐parameter weight function on the interval . The spreading of its associated probability density (i.e., the Rakhmanov density) over the support interval has been quantified, beyond the dispersion measures (moments around the origin, variance), by the algebraic (Shannon and Rényi entropies) and the monotonic complexity‐like measures of Cramér–Rao, Fisher–Shannon, and LMC (López‐Ruiz, Mancini, and Calbet) types. These quantities, however, have been often determined in an analytically highbrow, non‐handy way; specially when the degree or the parameters are large. In this work, we determine in a simple, compact form the leading term of the entropic and complexity‐like properties of the Jacobi polynomials in the two extreme situations: (; fixed ) and (; fixed ). These two asymptotics are relevant per se and because they control the physical entropy and complexity measures of the high energy (Rydberg) and high dimensional (pseudoclassical) states of many exactly, conditional exactly, and quasi‐exactly solvable quantum‐ mechanical potentials which model numerous atomic and molecular systems.
Joint power allocation and cooperative analog beamforming for ultra‐dense low Earth orbit satellite constellation networks
Authors: Tong Jianfei , Wang Cheng , Zhao Xiaoyan , Cui Gaofeng , Wang Weidong 
Published: December 2021

SummaryIn this paper, downlink multigroup multicast transmission in the ultra‐dense low Earth orbit satellite constellation networks with full frequency reuse is studied. Multicast transmission significantly improves the system performance compared with point‐to‐point transmission. However, multicast capacity is constrained by the signal to interference and noise ratio (SINR) of bottleneck users in each group. To tackle this problem, we propose an alternating optimization‐based joint power allocation and cooperative beamforming algorithm (AO‐JPACB) to enhance the SINR of the bottleneck users and improve the system capacity. Simulation results show that the proposed AO‐JPACB algorithm can improve the system capacity compared to single‐satellite schemes.
Heavy Fluorination via Ion Exchange Achieves High‐Performance Li–Mn–O–F Layered Cathode for Li‐Ion Batteries
Authors: Lu Junliang , Cao Bo , Hu Bingwen , Liao Yuxin , Qi Rui , Liu Jiajie , Zuo Changjian , Xu Shenyang , Li Zhibo , Chen Cong , Zhang Mingjian , Pan Feng 
Published: December 2021

AbstractLithium‐excess manganese layered oxide Li2MnO3, attracts much attention as a cathode in Li‐ion batteries, due to the low cost and the ultrahigh theoretical capacity (≈460 mA h g−1). However, it delivers a low reversible practical capacity (<200 mA h g−1) due to the irreversible oxygen redox at high potentials (>4.5 V). Herein, heavy fluorination (9.5%) is successfully implemented in the layered anionic framework of a Li–Mn–O–F (LMOF) cathode through a unique ion‐exchange route. F substitution with O stabilizes the layered anionic framework, completely inhibits the O2 evolution during the first cycle, and greatly enhances the reversibility of oxygen redox, delivering an ultrahigh reversible capacity of 389 mA h g−1, which is 85% of the theoretical capacity of Li2MnO3. Moreover, it also induces a thin spinel shell coherently forming on the particle surface, which greatly improves the surface structure stability, making LMOF exhibit a superior cycling stability (a capacity retention of 91.8% after 120 cycles at 50 mA g−1) and excellent rate capability. These findings stress the importance of stabilizing the anionic framework in developing high‐performance low‐cost cathodes for next‐generation Li‐ion batteries.
Edge‐Site‐Rich Ordered Macroporous BiOCl Triggers CO Activation for Efficient CO2 Photoreduction
Authors: Liu Gaopeng , Wang Bin , Zhu Xingwang , Ding Penghui , Zhao Junze , Li Huaming , Chen Ziran , Zhu Wenshuai , Xia Jiexiang 
Published: December 2021

AbstractEndowing a semiconductor with tunable edge active sites will effectively enhance catalytic performance. Herein, an edge‐site‐rich ordered macroporous BiOCl (BiOCl‐P) with abundant dangling bonds is constructed via the colloidal crystal template method. The edge‐site‐rich ordered macroporous structure provides abundant adsorption sites for CO2 molecules, as well as forms numerous localized electron enrichment areas, accelerating charge transfer. DFT calculations reveal that the dangling bonds‐rich configuration can effectively reduce the CO2 activation energy barrier, boost the CO double bond dissociation, and facilitate the proton electron coupling reaction. As a result, the BiOCl‐P achieves a higher CO and CH4 generation rate of 78.07 and 3.03 µmol g−1 under 4 h Xe lamp irradiation in a solid–gas system. Finally, the CO2 molecules′ conversion process is further investigated by in situ Fourier‐transform infrared spectroscopy. This work realizes a new avenue toward the design of vibrant semiconductors on the nanoscale to boost inert CO2 photoreduction.
BlockchainBus: A lightweight framework for secure virtual machine migration in cloud federations using blockchain
Authors: Doyle Joseph , Golec Muhammed , Gill Sukhpal Singh 
Published: December 2021

AbstractCloud federations offer numerous advantages such as improved resilience, improved performance, and the prevention of vendor lock‐in. In order to function efficiently, however, they must be supported by automated solutions to deploy cloud resources securely and efficiently. In particular, a system which allows virtual machine (VM) migration from one cloud to another while recording this for charging and security purposes is particularly useful. This paper presents a lightweight framework called BlockchainBus which offers secure VM migration in cloud federations using blockchain. This framework is a VM migration Blockchain ledger which can be used to record these migrations. BlockchainBus framework is implemented using the HyperLedger solution and deployed on the Microsoft Azure cloud platform. The overhead of this system is then evaluated. The performance of the BlockchainBus framework was compared with the overall VM migration time and was determined as 2.36 seconds. This result is shorter than the overall VM migration time of 5 seconds and indicates that the BlockchainBus gives better performance.