bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electronic spectral diffusion in glasses: The influence of coupling to the medium on experimental observables
Authors: Zimdars David , Fayer M. D. 
Published: July 2002

The theory of electronic dephasing in low temperature glasses is extended to include the possibility that the strength of coupling of the chromophore to the solvent medium depends on the nature of the bath dynamical processes and the nature of the chromophore and, therefore, the chromophore-bath coupling can vary as a function of the rate of the dynamics of the medium. In the context of the sudden jump two-level system (TLS) model of low temperature glasses, this theory is used to reconcile the apparent contradiction implied by differences observed in spectral diffusion data for cresyl violet and metal-porphyrins in deuterated ethanol glass at 1.5 K. Previously, the coupling strength of a chromophore to the TLS has been assumed to be independent of rate of the transition between TLS states. Within the context of this approximation, spectral diffusion data yield, Pi(R), the intrinsic TLS fluctuation rate distribution. With the inclusion of the rate dependent coupling, C(R), it is shown that the spectral diffusion observables actually yield Pi(R)C(R). Therefore, the observed lack of spectral diffusion for a particular chromophore over some range of times can imply C(R) is zero rather than the current interpretation that Pi(R) is zero.
To illustrate the importance of C(R), a hueristic model is analyzed. A fluctuation rate distribution is introduced that consists of the sum of three log-normal functions each associated with a specific class of dynamics occurring over three overlapping ranges of rates. The uncharged and nonpolar metal porphyrins is taken to couple to TLS strain dipoles, while the charged and polar cresyl violet also couples to TLS electric dipoles. By taking one of the types of TLS dynamics to only give rise to electric dipole fluctuations, it is possible to fit all of the experimental data in deuterated ethanol with a single intrinsic distribution of TLS fluctuation rates. This analysis of previously reported data is supported by the presentation of new stimulated photon echo data on both cresyl violet and zinc meso-tetraphenyl porphine in deuterated ethanol.
Dynamics of concentration and vorticity modification in a cellular flow laden with solid heavy particles
Authors: Druzhinin O. A. 
Published: July 2002

The processes of the accumulation of solid heavy particles settling under gravity and modification of the carrier flow are studied analytically and numerically. The dilute limit is considered when the effects of particle–particle interactions are neglected. The flow Reynolds number is assumed to be large enough to disregard effects related to the viscous dissipation. Particles with a small Stokes (St) number are considered, when approximate solution for the particulate velocity in the form of a series in St can be derived.
Analytical solutions are obtained for initially uniform distribution of particles in a cellular flow (formed by a lattice of two-dimensional vortices with different circulations) describing dynamics of the particulate concentration and corresponding modification of the fluid flow. Two different regimes of large and moderate flow Froude number (Fr) are considered. Solutions obtained show that in the first case (Fr≫1), when the gravitational settling of the particles is insignificant, the concentration of particles drops at the centers and grows at the periphery of the vortices, so that sheets of the increased concentration are formed in the vicinity of the flow separatrices. Due to the coupling between the particulate and fluid dynamics, the flow vorticity is reduced at the cells centers. The flow gradients grow due to the drag forces between the two phases and sheets of increased vorticity are generated in the vicinity of the concentration sheets. In the case Fr∼1 the concentration sheets correspond to the particle settling paths. Vorticity is effectively generated in the vicinity of these paths, where the drag force based on the local slip velocity is enhanced by the settling. As a result, vortex centers are shifted toward the settling paths, so that the whole symmetry of the flow is changed by the coupling. Results of direct numerical simulations performed for St∼1 show a good agreement with analytical solutions.
It is observed also that the average value of particle settling velocity may exceed that in the still fluid (similar to the earlier result obtained by Maxey [Philos. Trans. R. Soc. London Ser. A 333, 289 (1990)] under assumption that the influence of the particulate on the carrier flow remains negligible).
Efficacy and Safety of Pacritinib vs Placebo for Patients With Severe COVID-19
Authors: Cafardi John , Miller Carole , Terebelo Howard , Tewell Chad , Benzaquen Sadia , Park David , Egan Pamela , Lebovic Daniel , Pettit Kristen , Whitman Eric , Tremblay Douglas , Feld Jonathan , Buckley Sarah , Roman-Torres Karisse , Smith Jennifer , Craig Adam , Mascarenhas John 
Published: December 2022

ImportanceThe morbidity and mortality associated with COVID-19 remain high despite advances in standard of care therapy, and the role of anti-inflammatory agents that inhibit the interleukin 6/JAK2 pathway is still being elucidated.ObjectiveTo evaluate the efficacy and safety of the oral JAK2/IRAK1 inhibitor pacritinib vs placebo in the treatment of adults with severe COVID-19.Design, Setting, and ParticipantsThis phase 2, double-blind, placebo-controlled, randomized clinical trial enrolled hospitalized adult patients with severe COVID-19 at 21 centers across the US between June 2020 and February 2021, with approximately 1.5 months of safety follow-up per patient. Data analysis was performed from September 2021 to July 2022.InterventionsPatients were randomized 1:1 to standard of care plus pacritinib (400 mg per os on day 1 followed by 200 mg twice daily on days 2-14) vs placebo, for 14 days.Main Outcomes and MeasuresThe primary end point was death or need for invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO) by day 28. All-cause mortality and safety were also assessed.ResultsA total of 200 patients were randomized to pacritinib (99 patients; 56 men [56.6%]; median [range] age, 60 [19-87] years) or placebo (101 patients; 64 men [63.4%]; median [range] age 59 [28-94] years). The percentage requiring supplementary oxygen was 99.0% (98 patients) in the pacritinib group vs 98.0% (99 patients) in the placebo group. The percentage who progressed to IMV, ECMO, or death was 17.2% (17 patients) in the pacritinib group vs 22.8% (23 patients) in the placebo group (odds ratio, 0.62; 95% CI, 0.28-1.35; P = .23). Among patients with elevated interleukin 6, the rate was 17.5% (11 of 63 patients) in the pacritinib group vs 30.4% (21 of 96 patients) in the placebo group. The adverse event rate was similar for pacritinib vs placebo (78.1% [75 patients] vs 80.2% [81 patients]), with no excess in infection (14.6% [14 patients] vs 19.8% [20 patients]), bleeding (8.3% [8 patients] vs 10.9% [11 patients]), or thrombosis (8.3% [8 patients] vs 7.9% [8 patients]). Rates of grade 3 or higher adverse events were lower with pacritinib than placebo (29.2% [28 patients] vs 40.6% [41 patients]).Conclusions and RelevanceThe study did not meet its primary end point in patients with severe COVID-19. Subgroup analyses may indicate specific populations with hyperinflammation that could benefit from pacritinib, although further clinical trials would be needed to confirm these effects.Trial RegistrationClinicalTrials.gov Identifier: NCT04404361
Construction and Application of Orthogonal T7 Expression System in Eukaryote: An Overview
Authors: Wang Wenya , An Xiaoyan , Yan Kun , Li Qiang 
Published: December 2022

AbstractThe T7 system is an orthogonal transcription‐system, which is characterized by simplicity, higher efficiency, and higher processivity, and it is used for protein or mRNA synthesis in various biological‐systems. In comparison with prokaryotes, the construction of the T7 expression system is still on‐going in eukaryotes, but it shows greatly applicable prospects. In the present paper, development of T7 expression system construction in eukaryotes is reviewed, including its construction in animal (mammalian cells, trypanosomatid protozoa, Xenopus oocytes, zebrafish), plant, and microorganism and its application in vaccine production and gene therapy. In addition, the innate challenges of T7 expression system construction in eukaryote and its potential application in vaccine production and gene therapy are discussed.
Spatiotemporal Regulation of Injectable Heterogeneous Silk Gel Scaffolds for Accelerating Guided Vertebral Repair
Authors: Wang Tianji , Liu Keyin , Wang Jing , Xiang Geng , Hu Xiaofan , Bai Hao , Lei Wei , Tao Tiger H. , Feng Yafei 
Published: December 2022

AbstractOsteoporotic vertebral fracture is jeopardizing the health of the aged population around the world, while the hypoxia microenvironment and oxidative damage of bone defect make it difficult to perform effective tissue regeneration. The balance of oxidative stress and the coupling of vessel and bone ingrowth are critical for bone regeneration. In this study, an injectable heterogeneous silk gel scaffold which can spatiotemporally and sustainedly release bone mesenchymal stem cell‐derived small extracellular vesicles, HIF‐1α pathway activator, and inhibitor is developed for bone repair and vertebral reinforcement. The initial enhancement of HIF‐1α upregulates the expression of VEGF to promote angiogenesis, and the balance of reactive oxygen species level is regulated to effectively eliminate oxidative damage and abnormal microenvironment. The subsequent inhibition of HIF‐1α avoids the overexpression of VEGF and vascular overgrowth. Meanwhile, complex macroporous structures and suitable mechanical support can be obtained within the silk gel scaffolds, which will promote in situ bone regeneration. These findings provide a new clinical translation strategy for osteoporotic vertebral augmentation on basis of hypoxia microenvironment improvement.
The Effect of Single versus Polycrystalline Cathode Particles on All‐Solid‐State Battery Performance
Authors: Payandeh Seyedhosein , Njel Christian , Mazilkin Andrey , Teo Jun Hao , Ma Yuan , Zhang Ruizhuo , Kondrakov Aleksandr , Bianchini Matteo , Brezesinski Torsten 
Published: December 2022

AbstractLithium‐thiophosphate‐based all‐solid‐state batteries (ASSBs) are increasingly attracting attention for high‐density electrochemical energy storage. In this work, the cycling performance of single and polycrystalline forms of LiNixCoyMnzO2 (NCM, with ≥83% Ni content) cathode active materials in ASSB cells with an Li4Ti5O12 composite anode is explored, and the advantages and disadvantages of both morphologies are discussed. The virtual lack of grain boundaries in the quasi‐single‐crystalline material is found to contribute to improved stability by eliminating the tendency of Ni‐rich NCM particles to crack during cycling, due to volume differences between the lithiated and delithiated phases. Although the higher crack resistance mitigates effects of chemical oxidation of the lithium thiophosphate solid electrolyte, the cells suffer from electrochemical side reactions occurring at the cathode interfaces. However, coating the single‐crystal particles with a protective LiNbO3 overlayer helps to stabilize the interface between cathode active material and solid electrolyte, leading to a capacity retention of 93% after 200 cycles (with qdis ≈ 160 mAh gNCM−1 or 1.7 mAh cm−2 at C/5 rate and 45 °C). Overall, this work highlights the importance of addressing electro‐chemo‐mechanical phenomena in ASSB electrodes.
Cataloguing MoSi2N4 and WSi2N4 van der Waals Heterostructures: An Exceptional Material Platform for Excitonic Solar Cell Applications
Authors: Tho Che Chen , Yu Chenjiang , Tang Qin , Wang Qianqian , Su Tong , Feng Zhuoer , Wu Qingyun , Nguyen C. V. , Ong Wee‐Liat , Liang Shi‐Jun , Guo San‐Dong , Cao Liemao , Zhang Shengli , Yang Shengyuan A. , Ang Lay Kee , Wang Guangzhao , Ang Yee Sin 
Published: December 2022

Abstract2D materials van der Waals heterostructures (vdWHs) provide a revolutionary route toward high‐performance solar energy conversion devices beyond the conventional silicon‐based pn junction solar cells. Despite tremendous research progress accomplished in recent years, the searches of vdWHs with exceptional excitonic solar cell conversion efficiency and optical properties remain an open theoretical and experimental quest. Here, this study shows that the vdWH family composed of MoSi2N4 and WSi2N4 monolayers provides a compelling material platform for developing high‐performance ultrathin excitonic solar cells and photonics devices. Using first‐principle calculations, 51 types of MoSi2N4 and WSi2N4‐based [(Mo,W)Si2N4] vdWHs composed of various metallic, semimetallic, semiconducting, insulating, and topological 2D materials are constructed and classified. Intriguingly, MoSi2N4/(InSe, WSe2) are identified as Type II vdWHs with exceptional excitonic solar cell power conversion efficiency reaching well over 20%, which are competitive to state‐of‐the‐art silicon solar cells. The (Mo,W)Si2N4 vdWH family exhibits strong optical absorption in both the visible and UV regimes. Exceedingly large peak UV absorptions over 40%, approaching the maximum absorption limit of a freestanding 2D material, can be achieved in (Mo,W)Si2N4/α2‐(Mo,W)Ge2P4 vdWHs. The findings unravel the enormous potential of (Mo,W)Si2N4 vdWHs in designing ultimately compact excitonic solar cell device technology.
Stepwise Reduction and In Situ Loading of Core‐Shelled Pt@Cu Nanocrystals on TiO2–NTs for Highly Active Hydrogen Evolution
Authors: Mao Binglong , Zhu Yiming , Huang Dihua , Zhang Jun , Liu Quanxing , Li Xiang , Song Kexing 
Published: December 2022

AbstractA flexible and mild fabricating protocol, i.e., stepwise reduction and in situ loading route, is proposed to modulate ordered growing and dispersive depositing of Pt@Cu bimetal layered nanostructure on titanium dioxide nanotubes (TiO2‐NTs) via reasonably regulating addition sequence and dosage for the reactants and additives. Comprehensive characterizations demonstrate that most of the Cu core‐Pt shell nanocrystals with a mean size of 10 nm evenly disperse on the surface of TiO2‐NTs, and a small number of nanocrystals permeate into the nanotubes. In comparison to TiO2‐NTs, the specific surface area declines after loading bimetals, with the pore size distribution shifting from micropores to mesopores. The catalytic activity of the Pt@Cu(x)/TiO2 for hydrolytic hydrogen evolution presents an increasing tendency as the bimetal loadings rise, each surpassing that of the bare bimetal nanocrystals. The H2 generating rate gradually rises with temperature increment. The AB hydrolysis catalyzed by Pt@Cu(9%)/TiO2 at the given temperatures (293–313 K) is affirmed as a first‐order reaction, with apparent activation energy of 28.43 kJ mol−1 and TOF value of 107.27 min−1. The catalyst Pt@Cu(9%)/TiO2 unfolds exceptionally high stability, remaining 91% initial catalytic activity after five cycling use.
Nanostructured Ag‐Bioglass Implant Coatings with Antibacterial and Osteogenic Activity
Authors: Geissel Felix J. , Platania Varvara , DeBerardinis Niccoló , Skjöldebrand Charlotte , Belibasakis Georgios N. , Persson Cecilia , Hulsart‐Billström Gry , Chatzinikolaidou Maria , Sotiriou Georgios A. 
Published: December 2022

AbstractBone implant failure due to aseptic loosening and biofilm infections is an increasing healthcare problem. Implants may be coated with nanoparticles to avoid bacterial colonization and promote osseointegration. However, these nanocoatings often require long, expensive, and complex manufacturing routes with limited clinical translation potential. Here, a multifunctional nanoparticle coating consisting of silver (Ag) and bioglass (BG) is investigated to overcome current limitations by providing synchronously antibacterial and osteogenic effect. Flame spray pyrolysis (FSP) is exploited as a scalable and reproducible process to synthesize large quantities of nanoparticles and deposit them on titanium (Ti) substrates. The deposited nanocoatings show a homogeneous morphology and biomineralize after soaking in simulated body fluid (SBF), while their adhesion on Ti substrates is promoted by in situ flame annealing. The Ag+ ion release from Ag containing BG samples inhibits Staphylococcus aureus biofilm formation up to 3 log units, while the osteogenic responses of pre‐osteoblastic cells directly grown on AgBG samples show similar levels of alkaline phosphatase activity, calcium and collagen production when compared to pure Ti. The inexpensively synthesized multifunctional AgBG nanostructured implant coatings exert a high bioactivity and antibacterial response while maintaining high biocompatibility. The insights of this study can direct the development of multifunctional implant coatings.
Supramolecular Pressure‐Sensitive Adhesives with Rapid, Strong, Water‐Resistant, and Underwater Adhesion
Authors: Li Jialing , Zhang Yunfei , Zhang Qiao , Cai Changyong , Li Fenfang , Dong Shengyi 
Published: December 2022

AbstractSupramolecular polymers are materials that exhibit a range of functionalities and thus find wide applicability. In this study, two natural low‐molecular‐weight compounds, thioctic acid (TA) and phytic acid (PA), are used to fabricate polymeric supramolecular structures. The coexistence of dynamically covalently linked poly(TA) and hydrogen bond linked poly(PA) moieties result in copolymeric materials with different dynamic features. The obtained poly(TA‐PA)s show rapid and strong adhesion on a variety of natural and artificial surfaces, with high 180° peeling, lap‐shear, and pull‐off strengths over wide temperature (−18 °C to 60 °C) and humidity (20−99%) ranges. The poly(TA‐PA)s also display good stability and adhesion in the presence of water, even show stable and long‐lasting underwater adhesion. Hence, the synthesized poly(TA‐PA)s, which have high water resistance, are suitable for use as sealing materials in various applications, thus highlighting the applicability of supramolecular polymer materials in underwater surface coatings and adhesion.
Disentangling Light‐Induced Charge Transfer, Heating, and Strain Effects in WS2/Graphene Heterostructures
Authors: Zhang Ruiling , Gan Lin , Zhang Danyang , Sun Hao , Li Yongzhuo , Ning Cun‐Zheng 
Published: December 2022

AbstractHeterostructures formed by 2D transition metal dichalcogenides (TMDCs) and graphene are not only fundamentally important for the exploration of novel interface physics but also indispensable for various optoelectronic devices. Often multiple effects such as charge transfer (CT), heating, and strain are present simultaneously and their interplay significantly impacts the properties of such heterostructures. However, the identification and separation of these three individual effects are challenging and have not been demonstrated in 2D heterostructures. Here, through a concurrent analysis of the Raman modes and photoluminescence spectra from graphene and WS2 in temperature‐ and power‐dependent measurements, this work has succeeded in disentangling the effects of light‐induced CT, heating, and strain effects in WS2/graphene heterostructure on SiO2/Si substrate. Without disentangling these effects, the light‐induced carrier density in graphene (WS2) would have been underestimated (overestimated) by up to 62% (73%) in this situation. More importantly, a positive temperature coefficient of the G‐mode Raman shift is obtained without excluding the strain and CT effects, contrary to the negative coefficient due to the intrinsic thermal effect. This study demonstrates the importance of disentangling the individual effects and the approach paves the way for a comprehensive understanding of electrical, thermal, and mechanical properties of TMDC/graphene heterostrucutres.
Electron Irradiation Frozen Effect in Stiff/Soft Bilayer Films
Authors: Meng Yancheng , Li Baowen , Li Luxian , Zhang Jianqiang , Guo Wanlin 
Published: December 2022

AbstractThe buckling behavior of stiff/soft bilayer films has been extensively studied over the past three decades. However, strategies to characterize buckling structures on complex surfaces caused by bilayer film deformation, such as bending and spherical bilayers, are still lacking, preventing an accurate understanding of buckling behaviors in a broader context. Here, a frozen effect in a stiff/soft bilayer film is reported which provides a solution to the aforementioned problem. The buckling patterns in the stiff/soft bilayer film can be frozen by electron‐beam irradiation, which is attributed to the irradiation‐induced hardening transition of the soft film. After local freezing, the buckling patterns on a complex surface can be positioned on a plane by eliminating the compression across the bilayer and, hence, can be characterized by conventional means. This frozen characterization technique is similar to cryo‐electron microscopy and has vast potential applications in many fields.
2D Metallic Abnormal Li2Cl Crystals with Unique Electronic Characteristics Applied in Capacitor and Humidity Sensor
Authors: Li Yunzhang , Zhao Yimin , Liu Xing , Qiu Yinwei , He Zhenglin , Zhang Shengli , Fang Haiping , Chen Liang , Zhang Lei , Shi Guosheng 
Published: December 2022

AbstractUnderstanding the configuration and properties of the simplest lithium‐ion crystal, the Li‐Cl crystal, is essential for developing Li‐based electrochemical energy storage and conversion devices. Under ambient conditions, LiCl in a 1:1 stoichiometry is the only known stable form of the Li‐Cl crystal, and the corresponding crystals are insulating. Here, using cryo‐electron microscopy (cryo‐EM) and X‐ray photoelectron spectroscopy (XPS), this work reports a novel abnormal 2D Li2Cl crystal in ultra‐thin reduced graphene oxide (rGO) membranes by simply soaking the rGO membrane in unsaturated LiCl solution under ambient conditions and showed its high‐resolution image. Unexpectedly, such Li2Cl crystal presents metallic properties rather than insulating properties. Using vacuum filtration of the unsaturated LiCl solution through rGO membranes, this work prepares the rGO membranes with high content Li2Cl, displaying a high areal capacitance of 220 mF cm−2. Remarkably, the Li2Cl‐rGO membranes also exhibit heterostructure property and piezoelectricity. For the excess Li and unique electrical characteristics, these Li2Cl‐rGO membranes can be used as a humidity sensor. These findings point to possibilities for creating new Li‐based materials and fabricating novel high‐performance electronic devices, transistors, and sensors.