bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on the Effect of Temperature on Tribological Properties of PTFE Composites under Oil Lubrication Conditions
Authors: Shi Jianwen , Suo Shuangfu , Zhang Qi 
Published: April 2021

Abstract
PTFE and its composites are widely used in various reciprocating sealing materials due to their extremely low friction coefficient. As pure PTFE has poor wear resistance at high temperature, it is necessary to study the tribological properties of PTFE with different fillers under the condition of high temperature and oil lubrication. The friction and wear properties of PTFE and PTFE composite material filled with bronze powder, carbon powder, carbon fiber, glass fiber and MoS2 powder were studied by standard friction and wear test using SRV-4 tribotester. Results showed that the wear resistance was all improved indicating that the fillers increased the wear resistance of PTFE, PTFE composite filled with MoS2 has the lowest coefficient at ambient temperature and the highest at high temperature, PTFE composites filled with carbon fiber have the lowest wear rate at all temperatures.
Simulation of Tensile Deformation Behavior of PM-SiCp/2014Al Composite Based on RVE
Authors: Yang Changyi , Wang Yingying , Fan Junxiang , Wu Yicheng , Jiao Haoyang , Li Fuguo 
Published: April 2021

Abstract
Metal matrix composite (MMC) emerges at the right moment and is widely used in aviation, aerospace and other fields due to its intrinsic properties. Usually compression tests are used to study the mechanical properties and deformation behavior of MMC. However, it is very important to study the deformation damage and fracture behavior of MMC under tensile stress state. At present, the design basis for MMC tensile stress state test still need further study. To this end, this paper uses the representative volume element (RVE) model, to simulate and analyze the tensile deformation behavior of particle-reinforced metal matrix composites (PRMMCS) for PM-SiCp/2014Al as the typical materials, and the deformation damage and fracture are analyzed and discussed.
The Influence of Material Matching and Rail Irregularities on Hypervelocity Gouging
Authors: Zhang Jingjing , Luo Jinglin 
Published: April 2021

Abstract
Gouging is a phenomenon of large non-linear deformations which may lead a permanent damage on a rocket-sled system. To analyze how gouging occurs and tracing of its development with different matching and rail irregularities, the influences of material matching and rail irregularities on hypervelocity gouging are studied by MPM algorithm in this paper. 5 sets of material matching and 5 set of rail irregularities cases have been simulated in this paper. The results show that gouges would be easier to occur with a lower yield strength material or a rail with irregularities. These results can help us find the methods to avoid gouging.
Study on Thermo-Mechanical Behaviors of Shape Memory Polymer Beam
Authors: Zhao Fei , Wang Feifei , Zhou Bo , Xue Shifeng 
Published: April 2021

Abstract
Shape memory polymer (SMP) is a new smart material and has attracted much attention of people and beam structure plays an important role in application of SMP. Thus, it is meaningful to study the thermo-mechanical behaviors of SMP beam. In this paper, a new constitutive model is established to study the thermo-mechanical behaviors of SMP beam. Based on the previous work, the SMP constitutive equation was further derived and the material parameter equation was introduced. According to the beam theory, SMP equation and the material parameter equation, the SMP beam model was established. And simply supported beams problem was taken for example to study the thermo-mechanical behaviors. The results show the viscous properties and shape memory effect of SMP beam and some conclusions are obtained. This work studies the thermo-mechanical behaviors of SMP beam and provides some theoretical basis for the application of SMP beam in the future.
Fabrication of a dual-layer cell-laden tubular scaffold for nerve regeneration and bile duct reconstruction
Authors: Liu Xixia , Yan Jianing , Liu Jingyi , Wang Yifan , Yin Jun , Fu Jianzhong 
Published: April 2021

Abstract
Tubular scaffolds serve as a controllable extracellular environment to guide the repair and regeneration of tissues. But it is still a challenge to achieve both excellent mechanical properties and cell compatibility of artificial scaffolds for long-term structural and biological stability. In this study, a four-step solution casting method was developed to fabricate dual-layer cell-laden tubular scaffolds for nerve and bile duct regeneration. The dual-layer tubular scaffold consisted of a bone marrow mesenchymal stem cells (BMSCs)-laden hydrogel inner layer and an outer layer of gelatin methacrylate (GelMA)/polyethylene glycol diacrylate. While the inner layer had a good biocompatibility, the outer layer had desired mechanical properties. The interfacial toughness, Young’s modulus, maximum tensile strain, and compressive modulus of dual-layer tubular scaffolds were 65 J m−2, 122.37 ± 23.21 kPa, 100.87 ± 40.10%, and 39.14 ± 18.56 N m−1, respectively. More importantly, the fabrication procedure was very cell-friendly, since the BMSC viability encapsulated in the inner layer of 10% (w/v) GelMA reached 94.68 ± 0.43% after 5 d of culture. Then, a preliminary evaluation of the potential application of dual-layer tubular scaffolds as nerve conduits and biliary scaffolds was performed, and demonstrated that the cell-laden dual-layer tubular scaffolds proposed in this work are expected to extend the application of tubular scaffolds in tissue engineering.
Enhanced circular dichroism of sparse nanoobjects by localized superchiral optical field
Authors: Rui Guanghao , Ying Xinyuan , Zou Shuting , Gu Bing , Cui Yiping 
Published: April 2021

AbstractThe spectroscopic methods of circular dichroism (CD) is commonly used in analysing the chirality of molecules, which plays an important role in pharmaceutical compounds. However, the current methods require high sample density due to the weak CD effect of natural material, making it challenging to detect the signal of individual chiral molecule. In this work, we propose a technique to enhance CD signal of individual chiral molecule with the use of superchiral optical field, which is acquired by focusing a twisted radially polarized vortex onto a one-dimensional photonic band gap structure. Through adjusting the topological charge and the focusing angle of the illumination, a deep subwavelength optical field with full width at half maxima (FWHM) of 0.02λand 22.4-fold superchirality factor enhancement can be generated. In addition, we demonstrate that up to 20-fold CD enhancement can be obtained by introducing 2 nm on-resonant chiral molecule into the superchiral optical field. This finding will have widely potential applications in CD spectroscopy and superresolution imaging for sparse subdiffraction chiral objects.
Shear viscoelasticity of electrospinning PCL nanofibers reinforced alginate hydrogels
Authors: Pang Lu , Sun Peixin , Dong Xufeng , Tang Tao , Chen Yi , Liu Qiang , Qi Min 
Published: April 2021

Abstract
Articular cartilage has limited self-repair capacity due to the lack of vascularization, innervation and lymphatic networks. Biomimetic scaffolds with features of the extracellular matrix (ECM) of cartilage are advantageous to repair the injured cartilage tissue, but it remains a challenge to regulate its shear viscoelasticity to meet the needs of applications as articular cartilages. Fiber reinforced hydrogel is of great significance for their clinical application as cartilage tissue engineering scaffolds, especially for repairing the fibrocartilage tissue like meniscus or temporomandibular joint disc. In order to promote the shear viscoelasticity of alginate hydrogels, which was seldom studied, electrospinning PCL nanofiber layers were added into the alginate hydrogels to prepare PCL nanofibers reinforced alginate hydrogel composites (PNRAHCs). Compared with neat alginate hydrogel scaffolds, the PNRAHCs presented coral-like structure and spider web-like structure, and some PCL nanofibers form reinforced fiber bundles. Those special structures make the PNRAHCs have higher porosity, higher shear storage modulus and higher shear loss modulus than the neat alginate hydrogels, indicating better shear mechanical properties. They have the potential to be applied as the scaffolds to repair fibrocartilage tissues.
Experimental demonstration of a quantum controlled-SWAP gate with multiple degrees of freedom of a single photon
Authors: Wang Feiran , Ru Shihao , Wang Yunlong , An Min , Zhang Pei , Li Fuli 
Published: April 2021

Abstract
Optimizing the physical realization of quantum gates is important to build a quantum computer. The controlled-SWAP gate, also named Fredkin gate, can be widely applicable in various quantum information processing schemes. In the present research, we propose and experimentally implement quantum Fredkin gate in a single-photon hybrid-degrees-of-freedom system. Polarization is used as the control qubit, and SWAP operation is achieved in a four-dimensional Hilbert space spanned by photonic orbital angular momentum. The effective conversion rate

P

of the quantum Fredkin gate in our experiment is (95.4 ± 2.6)%. Besides, we find that a kind of Greenberger–Horne–Zeilinger-like states can be prepared by using our quantum Fredkin gate, and these nonseparale states can show its quantum contextual characteristic by the violation of Mermin inequality. Our experimental design and coding method are useful for quantum computing and quantum fundamental study in high-dimensional and hybrid coding quantum systems.
Enabling effective electrochemical healing of structural steel
Authors: Hsain Zakaria , Jiang Zhimin , Pikul James H 
Published: April 2021

Abstract
Low-carbon steel is a widely used structural metal that, when fractured, can be repaired with high temperature processes. There are many applications, however, that would benefit from a room-temperature repair process which maintains the steel microstructure and prevents nearby materials and electronics from overheating. This work seeks to enable effective room-temperature healing of steel by understanding how ion transport and electrolyte chemistry influence growth morphology and strength in fractured steel struts repaired with nickel electrodeposition. Experiments and simulations show that pulsed electroplating mitigates diffusion-limited growth to enable smooth and dense nickel deposits that have 4× higher adhesion to steel than nickel deposited by potentiostatic electroplating. By combining pulsed electroplating and electrolyte chemistry selection, fully fractured steel wires could be repaired to achieve up to 69% of their pristine wire strength. Finally, a simple geometric model highlights the advantageous energy and time requirements of electrochemical healing across length scales.
Lead confinement and fluorimetric detection using zeolites: towards a rapid and cost-effective detection of lead in water
Authors: Moreno-Torres José Adán , Flores-Acosta Mario , Ramírez-Bon Rafael , Coutino-Gonzalez Eduardo 
Published: April 2021

Abstract
Metal clusters stabilized in zeolites have emerged as promising candidates for optoelectronic applications due to their remarkable luminescent properties. These optical properties have been exploited to develop fast and highly sensitive methods for optical sensing in environmental monitoring. However, to date, these materials have not been proposed as a detection method based on their luminescent response for sensing toxic metal ions. In this report, we synthesized luminescent lead (Pb) clusters into the cavities of synthetic F9-NaX zeolites, which were used as scaffolds to confine and detect Pb2+ ions in water through a fluorimetric mode. These Pb-F9 samples display an intense cyan emission in dehydrated form. Also, a correlation between the luminescence intensity of the materials and the lead loadings was observed, obtaining a low limit of detection of 1.248 ppb and a limit of quantification of 3.782 ppb. The results clearly demonstrate the potential of luminescent lead-exchanged F9 zeolites as one-step method for lead monitoring in water using a rapid and low-cost strategy.
The SparSpec algorithm and the application to the detection of spatial periodicities in tokamaks: error weighting the penalization criterion to improve the performance of the algorithm
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Authors: Testa D , Carfantan H , Perrone L M 
Published: April 2021

Abstract
A common problem in many complex physical systems is the determination of pulsation modes from irregularly sampled time-series, and there is a wealth of signal processing techniques that are being applied to post-pulse and real-time data analysis in such complex systems. The aim of this report is studying the problem of detecting discrete spatial periodicities in the spectrum of magnetic fluctuations in tokamaks, for which the optimization of the algorithm performance is essential, particularly when multiple sensors are used with different measurement uncertainties, and some of the processed output signals are then used in real-time for discharge control. The main tool used hereafter will be the SparSpec algorithm, initially devised for astrophysical purposes and already applied to the analysis of magnetic fluctuations in various tokamaks. In its baseline version, dubbed SS-H2, the SparSpec algorithm runs in currently or previously operating tokamaks (JET, TCV and Alcator C-mod), and is foreseen to be deployed for data analysis in tokamak under construction (ITER, DTT). For JET, SS-H2 regularly runs also in real-time on a 1ms clock for detecting Alfvén Eigenmodes using synchronously-measured magnetic perturbations. On JET and TCV, it was noted that often a reduced set of sensors had to be used as the measurement uncertainties were not the same for all available sensors, somewhat deteriorating the overall performance of the algorithm. Hence, as part of a major update of the SparSpec algorithm, specifically intended for accelerating the real-time performance, use of the measurement uncertainties to weight the data, the spectral window and the ensuing penalization criterion was introduced. The behaviour of this new version of the SparSpec algorithm under a variety of simulated circumstances is analysed. It is found that the implementation of SparSpec using such error weighting produces superior results to those obtained with SS-H2, both in terms of the speed and the accuracy of the calculations. A test on actual data from the JET tokamak also shows a clear improvement in the performance of the algorithm.
New horizons in falls prevention and management for older adults: a global initiative
Authors: Montero-Odasso Manuel , van der Velde Nathalie , Alexander Neil B , Becker Clemens , Blain Hubert , Camicioli Richard , Close Jacqueline , Duan Leilei , Duque Gustavo , Ganz David A , Gómez Fernando , Hausdorff Jeffrey M , Hogan David B , Jauregui Jose R , Kenny Rose Anne , Lipsitz Lewis A , Logan Pip A , Lord Stephen R , Mallet Louise , Marsh David R , Martin Finbarr C , Milisen Koen , Nieuwboer Alice , Petrovic Mirko , Ryg Jesper , Sejdic Ervin , Sherrington Cathie , Skelton Dawn A , Speechley Mark , Tan Maw Pin , Todd Chris , van der Cammen Tischa , Verghese Joe , Kamkar Nellie , Sarquis-Adamson Yanina , Masud Tahir ,   the Task Force on Global Guidelines for Falls in Older Adults
Published: April 2021

Abstract

Background
falls and fall-related injuries are common in older adults, have negative effects both on quality of life and functional independence and are associated with increased morbidity, mortality and health care costs. Current clinical approaches and advice from falls guidelines vary substantially between countries and settings, warranting a standardised approach. At the first World Congress on Falls and Postural Instability in Kuala Lumpur, Malaysia, in December 2019, a worldwide task force of experts in falls in older adults, committed to achieving a global consensus on updating clinical practice guidelines for falls prevention and management by incorporating current and emerging evidence in falls research. Moreover, the importance of taking a person-centred approach and including perspectives from patients, caregivers and other stakeholders was recognised as important components of this endeavour. Finally, the need to specifically include recent developments in e-health was acknowledged, as well as the importance of addressing differences between settings and including developing countries.

Methods
a steering committee was assembled and 10 working Groups were created to provide preliminary evidence-based recommendations. A cross-cutting theme on patient’s perspective was also created. In addition, a worldwide multidisciplinary group of experts and stakeholders, to review the proposed recommendations and to participate in a Delphi process to achieve consensus for the final recommendations, was brought together.

Conclusion
in this New Horizons article, the global challenges in falls prevention are depicted, the goals of the worldwide task force are summarised and the conceptual framework for development of a global falls prevention and management guideline is presented.
Duration of antibiotic treatment using procalcitonin-guided treatment algorithms in older patients: a patient-level meta-analysis from randomized controlled trials
Authors: Heilmann Eva , Gregoriano Claudia , Annane Djillali , Reinhart Konrad , Bouadma Lila , Wolff Michel , Chastre Jean , Luyt Charles-Edouard , Tubach Florence , Branche Angela R , Briel Matthias , Christ-Crain Mirjam , Welte Tobias , Corti Caspar , de Jong Evelien , Nijsten Maarten , de Lange Dylan W , van Oers Jos A H , Beishuizen Albertus , Girbes Armand R J , Deliberato Rodrigo O , Schroeder Stefan , Kristoffersen Kristina B , Layios Nathalie , Damas Pierre , Lima Stella S S , Nobre Vandack , Wei Long , Oliveira Carolina F , Shehabi Yahya , Stolz Daiana , Tamm Michael , Verduri Alessia , Wang Jin-Xiang , Drevet Sabine , Gavazzi Gaetan , Mueller Beat , Schuetz Philipp 
Published: April 2021

Abstract

Background
Older patients have a less pronounced immune response to infection, which may also influence infection biomarkers. There is currently insufficient data regarding clinical effects of procalcitonin (PCT) to guide antibiotic treatment in older patients.

Objective and design
We performed an individual patient data meta-analysis to investigate the association of age on effects of PCT-guided antibiotic stewardship regarding antibiotic use and outcome.

Subjects and methods
We had access to 9,421 individual infection patients from 28 randomized controlled trials comparing PCT-guided antibiotic therapy (intervention group) or standard care. We stratified patients according to age in four groups (&lt;75 years [n = 7,079], 75–80 years [n = 1,034], 81–85 years [n = 803] and &gt;85 years [n = 505]). The primary endpoint was the duration of antibiotic treatment and the secondary endpoints were 30-day mortality and length of stay.

Results
Compared to control patients, mean duration of antibiotic therapy in PCT-guided patients was significantly reduced by 24, 22, 26 and 24% in the four age groups corresponding to adjusted differences in antibiotic days of −1.99 (95% confidence interval [CI] −2.36 to −1.62), −1.98 (95% CI −2.94 to −1.02), −2.20 (95% CI −3.15 to −1.25) and − 2.10 (95% CI −3.29 to −0.91) with no differences among age groups. There was no increase in the risk for mortality in any of the age groups. Effects were similar in subgroups by infection type, blood culture result and clinical setting (P interaction &gt;0.05).

Conclusions
This large individual patient data meta-analysis confirms that, similar to younger patients, PCT-guided antibiotic treatment in older patients is associated with significantly reduced antibiotic exposures and no increase in mortality.
Co-ordination between leaf biomechanical resistance and hydraulic safety across 30 sub-tropical woody species
Authors: Wang Yong-Qiang , Ni Ming-Yuan , Zeng Wen-Hao , Huang Dong-Liu , Xiang Wei , He Peng-Cheng , Ye Qing , Cao Kun-Fang , Zhu Shi-Dan 
Published: April 2021

Abstract

Background and Aims
Leaf biomechanical resistance protects leaves from biotic and abiotic damage. Previous studies have revealed that enhancing leaf biomechanical resistance is costly for plant species and leads to an increase in leaf drought tolerance. We thus predicted that there is a functional correlation between leaf hydraulic safety and biomechanical characteristics.

Methods
We measured leaf morphological and anatomical traits, pressure–volume parameters, maximum leaf hydraulic conductance (Kleaf-max), leaf water potential at 50 % loss of hydraulic conductance (P50leaf), leaf hydraulic safety margin (SMleaf), and leaf force to tear (Ft) and punch (Fp) of 30 co-occurring woody species in a sub-tropical evergreen broadleaved forest. Linear regression analysis was performed to examine the relationships between biomechanical resistance and other leaf hydraulic traits.

Key Results
We found that higher Ft and Fp values were significantly associated with a lower (more negative) P50leaf and a larger SMleaf, thereby confirming the correlation between leaf biomechanical resistance and hydraulic safety. However, leaf biomechanical resistance showed no correlation with Kleaf-max, although it was significantly and negatively correlated with leaf outside-xylem hydraulic conductance. In addition, we also found that there was a significant correlation between biomechanical resistance and the modulus of elasticity by excluding an outlier.

Conclusions
The findings of this study reveal leaf biomechanical–hydraulic safety correlation in sub-tropical woody species.
Age-dependent Immune Response to the Biontech/Pfizer BNT162b2 Coronavirus Disease 2019 Vaccination
Authors: Müller Lisa , Andrée Marcel , Moskorz Wiebke , Drexler Ingo , Walotka Lara , Grothmann Ramona , Ptok Johannes , Hillebrandt Jonas , Ritchie Anastasia , Rabl Denise , Ostermann Philipp Niklas , Robitzsch Rebekka , Hauka Sandra , Walker Andreas , Menne Christopher , Grutza Ralf , Timm Jörg , Adams Ortwin , Schaal Heiner 
Published: April 2021

Abstract

Background
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to the development of various vaccines. Real-life data on immune responses elicited in the most vulnerable group of vaccinees older than age 80 years old are still underrepresented despite the prioritization of the elderly in vaccination campaigns.

Methods
We conducted a cohort study with 2 age groups, young vaccinees below the age of 60 years and elderly vaccinees over the age of 80 years, to compare their antibody responses to the first and second dose of the BNT162b2 coronavirus disease 2019 vaccination.

Results
Although the majority of participants in both groups produced specific immunoglobulin G antibody titers against SARS-CoV-2 spike protein, titers were significantly lower in elderly participants. Although the increment of antibody levels after the second immunization was higher in elderly participants, the absolute mean titer of this group remained lower than the &lt;60 years of age group. After the second vaccination, 31.3% of the elderly had no detectable neutralizing antibodies in contrast to the younger group, in which only 2.2% had no detectable neutralizing antibodies.

Conclusions
Our data showed differences between the antibody responses raised after the first and second BNT162b2 vaccination, in particular lower frequencies of neutralizing antibodies in the elderly group. This suggests that this population needs to be closely monitored and may require earlier revaccination and/or an increased vaccine dose to ensure stronger long-lasting immunity and protection against infection.