bluuebunny/crossref_metadata_2025_split huggingface dataset:
The thermoelectric potential of molten salt thermocells
Authors: K Cornwell  
Published: July 2002

The thermoelectric potential of a molten salt thermocell is not only dependent on the molten salt but also on the types of electrodes used for measurement. The thermo-electric potential of a thermocell with reversible electrodes constructed of the metal of the salt is determined by the entropy changes of the cation and is termed the `cationic thermoelectric potential' by the author. Similarly, electrodes of the anionic component of the salt lead to an anionic thermoelectric potential. This paper is concerned with the thermoelectric potential of cationic thermocells containing pure salts, and binary mixtures of pure salts with a common anion or cation. Previous work has been reviewed and the theory of the thermoelectric potential and the entropies of transfer of ions in mixtures of salts has been extended. Experimental studies of cells containing argentous and cuprous halide mixtures between pure metal and alloy electrodes have generally confirmed this theory.The possibility of using the thermoelectric potential of a molten salt thermocell for electrical generation was examined experimentally by the construction of a 13 V trial generator. This form of direct generation was shown to be possible but the expected efficiency of no more than 10% rather limited the field of application.
Effects of clumps and ion bombardment on electrical breakdown in vacuum
Authors: G P Beukema  
Published: July 2002

The formation of emitting sites on highly polished stainless steel and titanium electrodes in vacuum is investigated. It is shown that during the first application of an electric field between broad-area electrodes clumps damage the cathode surface. These clumps originate both from the cathode and the anode. If a spark-conditioned cathode with a field enhancement factor β=40 is placed opposite a new anode, an electric field of 6·5×106V m−1is enough to damage the cathode, resulting in a field enhancement factor of 100. It is demonstrated that conditioning of electrodes by sparks results from the detachment of more or less loosely bound particles from the electrodes. For small electrode separations (d<1 mm) clumps initiate a breakdown if the microscopic field strength βV/dafter the impact on the cathode is higher than a critical field strengthFb, which equals similar 7×109V m−1.The field enhancement factor β can be decreased by ion bombardment, but the breakdown voltage is the same as after spark conditioning. It is shown that after conditioning by ion bombardment clumps are responsible for the onset of a spark.
Empirical estimation of the reliability of ribosomal RNA alignments.
Authors: O'Brien E A , Higgins D G 
Published: July 2002

Abstract
MOTIVATION: The automatic alignment of rRNA sequences can reproduce manual expert alignments with high, but not perfect, fidelity. We examine the use of empirical methods for the identification of regions of an alignment of a new sequence with an existing large alignment which can confidently be predicted to be correctly aligned. RESULTS: We show how to use a simple jack-knife procedure to derive an estimate of the reliability that is to be expected at each position of a large alignment of eukaryotic rRNA sequences. These reliabilities are then improved using measures that are specific to the input sequence. Regions where the sequence-specific reliability method performs particularly well are identified and seen to correspond with elements in the structure of the rRNA molecules that vary between species in the alignment. We also compare these reliability measures to an algorithmic alignment stability measure. AVAILABILITY: The software is available free of charge by sending an e-mail message to emmet@chah.ucc.ie. CONTACT: emmet@chah.ucc.ie
Family pairwise search with embedded motif models.
Authors: Grundy W N , Bailey T L 
Published: July 2002

Abstract
MOTIVATION: Statistical models of protein families, such as position-specific scoring matrices, profiles and hidden Markov models, have been used effectively to find remote homologs when given a set of known protein family members. Unfortunately, training these models typically requires a relatively large set of training sequences. Recent work (Grundy, J. Comput. Biol., 5,&lt;479-492, 1998) has shown that, when only a few family members are known, several theoretically justified statistical modeling techniques fail to provide homology detection performance on a par with Family Pairwise Search (FPS), an algorithm that combines scores from a pairwise sequence similarity algorithm such as BLAST. RESULTS: The present paper provides a model-based algorithm that improves FPS by incorporating hybrid motif-based models of the form generated by Cobbler (Henikoff and Henikoff, Protein Sci., 6, 698-705, 1997). For the 73 protein families investigated here, this cobbled FPS algorithm provides better homology detection performance than either Cobbler or FPS alone. This improvement is maintained when BLAST is replaced with the full Smith-Waterman algorithm. AVAILABILITY: http://fps.sdsc.edu
Expression, purification, and activities of full‐length and truncated versions of the integral membrane protein Vpu from HIV‐1
Authors: Ma Che , Marassi Francesca M. , Jones David H. , Straus Suzana K. , Bour Stephan , Strebel Klaus , Schubert Ulrich , Oblatt‐Montal Myrta , Montal Mauricio , Opella Stanley J. 
Published: July 2002

AbstractVpu is an 81‐residue accessory protein of HIV‐1. Because it is a membrane protein, it presents substantial technical challenges for the characterization of its structure and function, which are of considerable interest because the protein enhances the release of new virus particles from cells infected with HIV‐1 and induces the intracellular degradation of the CD4 receptor protein. The Vpu‐mediated enhancement of the virus release rate from HIV‐1‐infected cells is correlated with the expression of an ion channel activity associated with the transmembrane hydrophobic helical domain. Vpu‐induced CD4 degradation and, to a lesser extent, enhancement of particle release are both dependent on the phosphorylation of two highly conserved serine residues in the cytoplasmic domain of Vpu. To define the minimal folding units of Vpu and to identify their activities, we prepared three truncated forms of Vpu and compared their structural and functional properties to those of full‐length Vpu (residues 2–81). Vpu2–37 encompasses the N‐terminal transmembrane α‐helix; Vpu2–51 spans the N‐terminal transmembrane helix and the first cytoplasmic α‐helix; Vpu28–81 includes the entire cytoplasmic domain containing the two C‐terminal amphipathic α‐helices without the transmembrane helix. Uniformly isotopically labeled samples of the polypeptides derived from Vpu were prepared by expression of fusion proteins in E. coli and were studied in the model membrane environments of lipid micelles by solution NMR spectroscopy and oriented lipid bilayers by solid‐state NMR spectroscopy. The assignment of backbone resonances enabled the secondary structure of the constructs corresponding to the transmembrane and the cytoplasmic domains of Vpu to be defined in micelle samples by solution NMR spectroscopy. Solid‐state NMR spectra of the polypeptides in oriented lipid bilayers demonstrated that the topology of the domains is retained in the truncated polypeptides. The biological activities of the constructs of Vpu were evaluated. The ion channel activity is confined to the transmembrane α‐helix. The C‐terminal α‐helices modulate or promote the oligomerization of Vpu in the membrane and stabilize the conductive state of the channel, in addition to their involvement in CD4 degradation.
A Gelation‐Assisted Approach for Versatile MXene Inks
Authors: Chen Derong , Long Yu , Wu Zhitan , Dong Ximan , Wang Ning , Yu Jinyang , Han Daliang , Tao Ying , Yang Quan‐Hong 
Published: July 2022

AbstractDue to outstanding electrical conductivity and excellent solution processing ability, MXenes show great potential as inks for printed/coated electronic devices. To meet the rheological requirements, an ultra‐high concentration is usually involved to formulate MXenes into versatile inks, however, low efficiency in rheology regulation, and restacking issues of MXene sheets hinder their further applications. Herein, a gelation‐assisted approach is proposed to prepare versatile MXene inks with a 3D interlinked network to well address above issues. With an effective combination of cross‐linking as well as the swelling of interlinked network, the gel ink exhibits tunable rheological properties by simply tuning the water amount within the sol‐gel system. Among various applicable printing/coating techniques ranging from painting to extrusion printing, blade coating is selected to demonstrate the advantage of MXene gel ink. The smooth coating layer with interlinked 3D structures is greatly beneficial to the uniform and dense zinc deposition with high reversibility, and endows the aqueous zinc ion batteries with a remarkable rate capability. This work provides an alternative approach to prepare versatile MXene inks and would offer MXenes new opportunities for their application in advanced printable electronic devices.
Directed Evolution Enables Simultaneous Controlled Release of Multiple Therapeutic Proteins from Biopolymer‐Based Hydrogels
Authors: Teal Carter J. , Hettiaratchi Marian H. , Ho Margaret T. , Ortin‐Martinez Arturo , Ganesh Ahil N. , Pickering Andrew J. , Golinski Alex W. , Hackel Benjamin J. , Wallace Valerie A. , Shoichet Molly S. 
Published: July 2022

AbstractWith the advent of increasingly complex combination strategies of biologics, independent control over their delivery is the key to their efficacy; however, current approaches are hindered by the limited independent tunability of their release rates. To overcome these limitations, directed evolution is used to engineer highly specific, low affinity affibody binding partners to multiple therapeutic proteins to independently control protein release rates. As a proof‐of‐concept, specific affibody binding partners for two proteins with broad therapeutic utility: insulin‐like growth factor‐1 (IGF‐1) and pigment epithelium‐derived factor (PEDF) are identified. Protein–affibody binding interactions specific to these target proteins with equilibrium dissociation constants (KD) between 10−7 and 10−8 m are discovered. The affibodies are covalently bound to the backbone of crosslinked hydrogels using click chemistry, enabling sustained, independent, and simultaneous release of bioactive IGF‐1 and PEDF over 7 days. The system is tested with C57BL/6J mice in vivo, and the affibody‐controlled release of IGF‐1 results in sustained activity when compared to bolus IGF‐1 delivery. This work demonstrates a new, broadly applicable approach to tune the release of therapeutic proteins simultaneously and independently and thus the way for precise control over the delivery of multicomponent therapies is paved.
Engineering MOFs‐Derived Nanoarchitectures with Efficient Polysulfides Catalytic Sites for Advanced Li–S Batteries
Authors: Tao Xuefeng , Yang Zhao , Yan Rui , Cheng Menghao , Ma Tian , Cao Sujiao , Bai Mingru , Ran Fen , Cheng Chong , Yang Wei 
Published: July 2022

AbstractLithium–sulfur batteries (LSBs) have received dramatically increased attention because of their manifest advantages. Nevertheless, due to the severe shuttling of lithium polysulfides (LiPSs), sluggish reaction kinetics, and the insulation of sulfur species, the practical application of LSBs is far away. To overcome the abovementioned issues, metal–organic frameworks (MOFs)‐derived nanoarchitectures have emerged as one of the most promising cathode materials in designing advanced Li–S batteries. This timely progress report highlights and comments on the most recent advances in designing MOFs‐derived nanoarchitectures with diverse electrocatalytic centers as cathode materials for catalyzing the oxidation/reduction reactions of LiPS in LSBs. The molecular/atomic‐level electrocatalytic centers, tunable porosities, large specific surface area, controlled components, and versatile structures of MOFs‐derived nanoarchitectures are carefully discussed for designing favorable electrocatalysts for LiPS. In particular, the catalytic mechanisms of LiPS based on different types of MOFs‐derived materials ranging from single atoms to nanoparticles are systematically summarized. Ultimately, the prospects and challenges of engineering MOFs‐derived catalysts for LiPS in LSBs are also suggested. It is believed that this progress report will offer potential guidance and instructive perspectives for designing future state‐of‐the‐art LiPS catalytic materials in LSBs.
Hierarchical Carbon Nanotube‐Supported Conductive Metal–Organic Framework Nanosheet toward High‐Strain Ionic Soft Actuator
Authors: Wu Yue , Shi Yi‐Xiang , Wang Ying‐Yi , Wang Yong‐Feng , Li Lian‐hui , Feng Si‐Min , Liu Lin , Li Li‐Li , Li Tie , Zhang Ting 
Published: July 2022

AbstractConductive metal–organic frameworks (MOFs) have recently been applied in electroactive ionic actuators due to their high surface areas and fast ion migration. However, their actuation performance needs to be promoted in terms of high conversion efficiency and large strain. Here, a soft ionic actuator is assembled by designing a hierarchical Cu‐MOFs‐based active material, which is composed of conductive Cu‐catecholate (Cu‐CAT) nanosheets covalently bridged by carboxylic multiwall carbon nanotubes (Cu‐CAT@MWCNT). Benefited from the large electromechanical deformation and rapid response rate of the Cu‐CAT@MWCNT electrodes, the assembled soft actuator exhibits large displacement of 16.6 mm with high bending strain of 0.52% (AC of ±3 V) and a high energy conversion efficiency (3.02%) with cycling stability over 10 000 cycles (in frequency range of 0.1–10 Hz). In addition, it demonstrates the capacity of gripping objects when assembled on a robot. The Cu‐CAT@MWCNT hybrid material‐based electrode points out a feasible pathway to construct soft actuators with improved performance and broadens their applications.
Investigation of Slip Sensing Technology Based on the Conductive Sponge‐PVDF
Authors: Wang Zhihua , Leng Hansong , Li Na , Yao Tao 
Published: July 2022

AbstractTactile sensation is one of the most important senses in living things and smart devices to obtain the required data from the outside world, and slip is one of the main tactile information. In the present study, a slip sensor made of conductive sponge and polyvinylidene fluoride (PVDF) is proposed to sense the magnitude and direction of the sliding force. The structure and working principle of the sensor are analyzed using the finite element method. Compared with the conventional room temperature vulcanized (RTV) silicone rubber and polydimethylsiloxane (PDMS) substrates, the conductive sponge not only provides good support for PVDF film and increases its output voltage but also can be used as an electrode to transfer electric charges. The performed experiments show that the response time of the tactile unit using the conductive sponge substrate is 48 ms, and the detection range of the tactile unit is 0.1–15 N. It is found that the designed sensor has a response time of 80 ms, a recovery time of 160 ms, and a measurement error of the angle perception is 4.54° ± 1.53°. Moreover, its detection error for shear force is 8.04% ± 5.8%. Accordingly, this method can be effectively applied to distinguish the magnitude and direction of the shear force and detect the object sliding in real‐time.
Mechanical Mode Engineering with Orthotropic Metamaterial Membranes
Authors: Conte Gloria , Vicarelli Leonardo , Zanotto Simone , Pitanti Alessandro 
Published: July 2022

AbstractMetamaterials are structures engineered at a small scale with respect to the wavelength of the excitations they interact with. These structures behave as artificial materials whose properties can be chosen by design, mocking and even outperforming natural materials, and making them the quintessential tool for manipulation of wave systems. In this paper it is shown how the acoustic properties of a silicon nitride membrane can be affected by nanopatterning. The degree of asymmetry in the pattern geometry induces an artificial anisotropic elasticity, resulting in the splitting of otherwise degenerate mechanical modes. The artificial material introduced has a maximum Ledbetter–Migliori anisotropy of 1.568, favorably comparing to most bulk natural crystals. With an additional freedom in defining arbitrary asymmetry axes by pattern rotation, the described approach can be useful for fundamental investigation of material properties as well as for devising improved sensors of light, mass, or acceleration based on micromechanical resonators.
Tailoring the Distinctive Chiral‐Polar Perovskites with Alternating Cations in the Interlayer Space for Self‐Driven Circularly Polarized Light Detection
Authors: Wu Wentao , Li Lina , Li Dong , Yao Yunpeng , Xu Zhijin , Liu Xitao , Hong Maochun , Luo Junhua 
Published: July 2022

AbstractChiral hybrid perovskites are recently considered for circularly polarized light (CPL) detection owing to the integration of chiral activity and prominent photoelectric characteristics. However, chiral hybrid perovskites are limited because of the restricted chiral cations; efficient self‐driven CPL detection without external power sources required for halide perovskite photodetectors is desirable but remains scarce. Herein, two alternating cations in the interlayer space of chiral‐polar hybrid perovskites, (R‐β‐MPA)EAPbBr4 and (S‐β‐MPA)EAPbBr4 (MPA = methylphenethylammonium and EA = ethylammonium), are developed via a mixed‐cation approach. These perovskites exhibit chiral characteristics featuring CPL detection with high detectivity. Notably, the chiral‐polar structure gives rise to a built‐in electric field to realize self‐driven CPL detection without an applied voltage, and the photocurrent difference reaches 19% under the right and left CPL irradiation. Moreover, a prominent response time of 300 µs is obtained, which is among the fastest for CPL detection. This work highlights the significance of chemical design in the exploration of new chiral perovskites, which will broaden the scope of chiral materials for high‐performance applications.
Acceptor Interlocked Molecular Design for Solution‐Processed Stable Deep‐Blue TADF and Hyper Fluorescence Organic LED Enabling High‐Efficiency
Authors: Alam Md Intekhab , Nagar Mangey Ram , Nayak Sandhya Rani , Choudhury A. , Jou Jwo‐Huei , Vaidyanathan Sivakumar 
Published: July 2022

AbstractSolution processed deep‐blue organic light emitting diodes (OLEDs) with high external quantum efficiency (EQE) and a long operational lifetime are still constrained. In this context, two thermally activated delayed fluorescence (TADF) emitters are synthesized utilizing a new design strategy of twisted interlocked acceptor core integrated with carbazole (KCCz) and tert‐butylcarbazole (KCTBC) as donors, respectively, for solution processed deep‐blue TADF OLEDs. Twisting of the acceptor core by two methyl groups results in complete separation of highest occupied molecular orbital and lowest unoccupied molecular orbital, along with cyanide group facilitating the generation of low‐lying triplet excited states as suggested by theoretical simulation. The combined effect of both results in tuning of emission in ultradeep blue region through the efficient population of triplet excitons and concurrently reverse intersystem crossing to produce highly efficient devices. A doped device based on KCTBC shows EQEmax of 9.0% along with low efficiency roll‐off with long operational device half lifetime of 72 min at initial brightness of 1000 cd m−2, and Commission Internationale de L'Eclairage (CIE) coordinates of (0.17, 0.13). In addition, with 12.5 wt% of 4CzFCN as assistant dopant/cohost the performance of the KCTBC‐based device is enhanced to an EQEmax of 13.9% and CIE coordinates of (0.18, 0.13). Further, a high‐efficiency warm white OLED adopting the TADF hybrid approach is realized with EQEmax of 9.0%.
Mesenchymal Stromal Cells Overexpressing Farnesoid X Receptor Exert Cardioprotective Effects Against Acute Ischemic Heart Injury by Binding Endogenous Bile Acids
Authors: Xia Yunlong , Xu Xinyue , Guo Yongzhen , Lin Chen , Xu Xiaoming , Zhang Fuyang , Fan Miaomiao , Qi Tingting , Li Congye , Hu Guangyu , Peng Lu , Wang Shan , Zhang Ling , Hai Chunxu , Liu Rui , Yan Wenjun , Tao Ling 
Published: July 2022

AbstractBile acid metabolites have been increasingly recognized as pleiotropic signaling molecules that regulate cardiovascular functions, but their role in mesenchymal stromal cells (MSC)‐based therapy has never been investigated. It is found that overexpression of farnesoid X receptor (FXR), a main receptor for bile acids, improves the retention and cardioprotection of adipose tissue‐derived MSC (ADSC) administered by intramyocardial injection in mice with myocardial infarction (MI), which shows enhanced antiapoptotic, proangiogenic, and antifibrotic effects. RNA sequencing, LC‐MS/MS, and loss‐of‐function studies reveal that FXR overexpression promotes ADSC paracrine angiogenesis via Angptl4. FXR overexpression improves ADSC survival in vivo but fails in vitro. By performing bile acid‐targeted metabolomics using ischemic heart tissue, 19 bile acids are identified. Among them, cholic acid and deoxycholic acid significantly increase Angptl4 secretion from ADSC overexpressing FXR and further improve their proangiogenic capability. Moreover, ADSC overexpressing FXR shows significantly lower apoptosis by upregulating Nqo‐1 expression only in the presence of FXR ligands. Retinoid X receptor α is identified as a coactivator of FXR. It is first demonstrated that there is a bile acid pool in the myocardial microenvironment. Targeting the bile acid‐FXR axis may be a novel strategy for improving the curative effect of MSC‐based therapy for MI.
A Versatile 3D‐Confined Self‐Assembly Strategy for Anisotropic and Ordered Mesoporous Carbon Microparticles
Authors: Wang Mian , Mao Xi , Liu Jingye , Deng Bite , Deng Shuai , Jin Shaohong , Li Wang , Gong Jiang , Deng Renhua , Zhu Jintao 
Published: July 2022

AbstractMesoporous carbon microparticles (MCMPs) with anisotropic shapes and ordered structures are attractive materials that remain challenging to access. In this study, a facile yet versatile route is developed to prepare anisotropic MCMPs by combining neutral interface‐guided 3D confined self‐assembly (3D‐CSA) of block copolymer (BCP) with a self‐templated direct carbonization strategy. This route enables pre‐engineering BCP into microparticles with oblate shape and hexagonal packing cylindrical mesostructures, followed by selective crosslinking and decorating of their continuous phase with functional species (such as platinum nanoparticles, Pt NPs) via in situ growth. To realize uniform in situ growth, a “guest exchange” strategy is proposed to make room for functional species and a pre‐crosslinking strategy is developed to preserve the structural stability of preformed BCP microparticles during infiltration. Finally, Pt NP‐loaded MCMPs are derived from the continuous phase of BCP microparticles through selective self‐templated direct carbonization without using any external carbon source. This study introduces an effective concept to obtain functional species‐loaded and N‐doped MCMPs with oblate shape and almost hexagonal structure (p6mm), which would find important applications in fuel cells, separation, and heterogeneous catalysis.