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Benefitting from the vast spatial degrees of freedom, the amalgamation of integrated sensing and communication (ISAC) and massive multiple-input multiple-output (MIMO) is expected to simultaneously improve spectral and energy efficiencies as well as the sensing capability. However, a large number of antennas deployed in massive MIMO-ISAC raises critical challenges in acquiring both accurate channel state information and target parameter information. To overcome these two challenges with a unified framework, we first analyze their underlying system models and then propose a novel tensor-based approach that addresses both the channel estimation and target sensing problems. Specifically, by parameterizing the high-dimensional communication channel exploiting a small number of physical parameters, we associate the channel state information with the sensing parameters of targets in terms of angular, delay, and Doppler dimensions. Then, we propose a shared training pattern adopting the same time-frequency resources such that both the channel estimation and target parameter estimation can be formulated as a canonical polyadic decomposition problem with a similar mathematical expression. On this basis, we first investigate the uniqueness condition of the tensor factorization and the maximum number of resolvable targets by utilizing the specific Vandermonde structure. Then, we develop a unified tensor-based algorithm to estimate the parameters including angles, time delays, Doppler shifts, and reflection/path coefficients of the targets/channels. In addition, we propose a segment-based shared training pattern to facilitate the channel and target parameter estimation for the case with significant beam squint effects. Simulation results verify our theoretical analysis and the superiority of the proposed unified algorithms in terms of estimation accuracy, sensing resolution, and training overhead reduction.

Time-modulated array (TMA) has garnered significant interest in recent years as an alternative to phased arrays for certain applications. The TMA offer advantages such as simplicity and high accuracy when employed in scanning mode. However, a significant limitation of TMA is the constrained signal bandwidth, which must be lower than the modulation frequency to avoid aliasing. This constraint can impede progress in wideband range-Doppler (RD) estimation. To address this problem, this article proposes a TMA structure and signal processing method that integrates time, frequency, and time–frequency (TF) domains to extract information for RD estimation. The proposed methods effectively overcome the bandwidth limitation by utilizing TF filtering and data fusion techniques, thereby enhancing the performance of RD estimation in TMA. The simulation results validate the effectiveness of the proposed strategies.

Compared with tuned mass damper (TMD), grounded tuned mass damper inerter (GTMDI) has higher damping efficiency and wider vibration control range. In the previous study of GTMDI design method, there was no clear basis for the determination of mass ratio and inerter-mass ratio simultaneously, and only the values of stiffness ratio and damping ratio can be determined in detail. For the deficiency, a global optimization design method of GTMDI is proposed in this paper with the two objectives of the performance demands of the original structure and the deformation performance of the damping element, namely, dual-demand-based optimal design method (DDOM). And the optimization objectives and optimization basis of the mass ratio and inerter-mass ratio are given in detail. After the target vibration mitigation ratio of the original structure is determined, four optimal design parameters of GTMDI can be obtained simultaneously by DDOM. The design concept of DDOM is that better energy dissipation effect is obtained through the deformation enhancement of damping element to control the vibration response of the main structure. At the same time, the values of optimal parameters of GTMDI are small, so the cost control can also be realized by DDOM.

The petroleum-based vinyl monomers have advanced society as the essential feedstock of synthetic polymers, producing over 150 million tons of attractive polymers annually. However, the carbon–carbon backbone of the produced polymer prevents materials from biodegradation and causes pollution to the environment. To combat this problem, a strategy of in situ epoxidation-copolymerization was proposed in this work to convert vinyl monomer styrene to biodegradable polyester. We designed and synthesized a series of tandem polymeric porphyrin catalysts with manganese and aluminum centers to tandemly catalyze the epoxidation of styrene and ring-opening copolymerization of epoxide and cyclic anhydride. Through mechanism exploration, the Mn and Al centers were proved to play leading roles in the epoxidation and the ring-opening copolymerization procedures, respectively, as expected. After optimizing the Mn:Al ratio of the polymeric catalyst (1:6), an alternating polyester with a high polymer selectivity of 94.4% could be achieved with the contents of the byproducts phenylacetaldehyde and benzaldehyde suppressed to <1 and 5.6%, respectively. Our present research proposed an in situ epoxidation-copolymerization strategy, providing a reliable platform for the transformation from commodity vinyl monomers to biodegradable materials.

The high-accuracy and resource-intensive deep neural networks (DNNs) have been widely adopted by live video analytics (VA), where camera videos are streamed over the network to resource-rich edge/cloud servers for DNN inference. Common video encoding configurations (e.g., resolution and frame rate) have been identified with significant impacts on striking the balance between bandwidth consumption and inference accuracy and therefore their adaption scheme has been a focus of optimization. However, previous profiling-based solutions suffer from high profiling cost, while existing deep reinforcement learning (DRL) based solutions may achieve poor performance due to the usage of fixed reward function for training the agent, which fails to craft the application goals in various scenarios. In this paper, we propose ILCAS, the first imitation learning (IL) based configuration-adaptive VA streaming system. Unlike DRL-based solutions, ILCAS trains the agent with demonstrations collected from the expert which is designed as an offline optimal policy that solves the configuration adaption problem through dynamic programming. To tackle the challenge of video content dynamics, ILCAS derives motion feature maps based on motion vectors which allow ILCAS to visually “perceive” video content changes. Moreover, ILCAS incorporates a cross-camera collaboration scheme to exploit the spatio-temporal correlations of cameras for more proper configuration selection. Extensive experiments confirm the superiority of ILCAS compared with state-of-the-art solutions, with 2–20.9% improvement of mean accuracy and 19.9–85.3% reduction of chunk upload lag.

Purpose: This study proposes a generalized type of tuned viscous mass damper (TVMD) considering dual-terminals and apparent mass amplification effect simultaneously, namely, lightweight tuned viscous mass damper (LwTVMD). Methods: The motion control equations of the LwTVMD system are established and the closed-form optimal expressions are derived based on H2optimization. And a dual-demand-based lightweight design approach is proposed to implement comprehensive reduction of design parameters. The rationality and superiority of this method are verified under typical excitations. Results: It is concluded that the closed-from optimal solutions based on terminal tuning stiffness element are very straightforward and easy to implement because the target vibration mitigation is only related to tuning stiffness ratio. Compared with TVMD, the same target vibration mitigation will be achieved using a smaller nominal damping ratio and mass ratio by increasing the amplifying ratio. At the same time, the proposed dual-demand-based lightweight design approach is an implementation of the damping-enhancement-based strategy. That guarantee satisfaction of the performance demand with the proper amplifying ratio to achieve damping enhancement effect using ultra low design parameters, which can produce cost-effective design schemes. Hence, a suitable amplifying ratio can be selected based on specific engineering cost, and the global optimization and lightweight design of TVMD can be completed. Conclusion: Due to the design method is based on analytical optimal formulas, all the design parameters of LwTVMD can be obtained directly when the performance objectives are determined. Damping efficiency of TVMD can be improved by using a specific and simple topological form, namely, rotating coaxial cylindrical flywheels. So optimized LwTVMD can satisfy the target structural demands considering a limited cost situation in practical engineering.

Sparse convolutional neural network (CNN) accelerators face challenges such as low utilization of processing elements (PEs), low data reuse, and high hardware sparse index addressing cost during convolution operations. This brief proposes a new scheduling strategy for feature map sparse vectors and convolution kernel sparse vectors based on the systolic array and row stationary (RS) dataflow to overcome these problems. Our approach employs a design and implementation of a sparse convolution operation module based on systolic array, simulated comprehensively in Vivado using Virtex-7 VX690T version at a clock frequency of 150 MHz with a circuit power consumption of 8.15 W. We utilized the VGG-16 model to test and analyze the sparse convolution operation module. Results indicate an average effective operation utilization rate of PE computing units processed by the VGG-16 convolution layer at 65.34%.

Purpose: Tuned viscous mass damper with negative stiffness (TVMDNS) has higher damping efficiency and broadband characteristics for vibration control by utilizing dual benefits of the inerter and negative stiffness. And single-performance H∞or H2optimal methods are adopted to determine the optimal parameters of TVMDNS individually. However, the vibration mitigation performance of the TVMDNS under high-frequency or resonance excitation based on H∞optimization is lesser than H2optimization, and quasi-static or low-frequency displacement response based on H2optimization will be greater than H∞optimization. An analytical strategy considering a dual-performance of H∞and H2norms is lacking at present. Methods: For this reason, closed-form expressions are derived for the control of structural displacement responses based on hybrid H2/H∞optimal approach. The vibration mitigation performance of the TVMDNS is evaluated considering harmonic, stochastic, and impulsive excitation using different optimal methods. Results: The initial static responses and ultra-low-frequency in hybrid H2/H∞optimal methods are between H2and H∞optimal design, and the high-frequency and resonance dynamic responses are also between those, which indicates an excellent and balanced control performance combining the advantages of H2and H∞solutions. And the global vibration control can be achieved by this dual-performance-based optimal strategy. Conclusion: When designing the specific TVMDNS, hybrid H2/H∞optimal design can be considered as the best choice for its compatibility and high adaptability for complex stochastic excitation. Furthermore, this approach can be extended for various topology connection forms of inerter and negative stiffness system for energy dissipation or vibration control.

Herein, we develop a base-promoted regioselective synthesis of N-vinyl pyrazoles from vinyl sulfonium salts with diazo compounds. This metal-free synthetic protocol provides an efficient and practical approach to diverse N-vinyl pyrazoles in good to excellent yields under mild conditions. The reaction appears to experience a [3 + 2] annulation of vinyl sulfonium salts and diazo anions rather than diazo compounds, followed by N-vinylation.

Herein, we disclose a visible-light-induced oxy-alkynylation of diazo compounds with ethynylbenziodoxolones. The efficient protocol provides a mild and metal-free methodology to synthesize propargylic esters in moderate to good yields. Notably, this metal-free carbene transfer reaction appears to involve an oxonium ylide intermediate, followed by intramolecular ligand exchange and reductive elimination.

ABSTRACTThe COVID-19 pandemic has caused substantial losses worldwide in people’s lives, health, and property. Currently, COVID-19 is still prominent worldwide without any specific drug treatment. The SARS-CoV-2 pathogen is the cause of various systemic diseases, mainly acute pneumonia. Within the pathological process, neutrophils are recruited to infected sites, especially in the lungs, for the first stage of removing invading SARS-CoV-2 through a range of mechanisms. Macroautophagy/autophagy, a conserved autodegradation process in neutrophils, plays a crucial role in the neutrophil phagocytosis of pathogens. NETosis refers to neutrophil cell death, while auto-inflammatory factors and antigens release NETs. This review summarizes the latest research progress and provides an in-depth explanation of the underlying mechanisms of autophagy and NETosis in COVID-19. Furthermore, after exploring the relationship between autophagy and NETosis, we discuss potential targets and treatment options. This review keeps up with the latest research on COVID-19 from neutrophil autophagy and NETosis with a new perspective, which can guide the urgent development of antiviral drugs and provide guidance for the clinical treatment of COVID-19.Abbreviations:AKT1: AKT serine/threonine kinase 1; AMPK: AMP-activated protein kinase; AP: autophagosome; ARDS: acute respiratory distress syndrome; ATG: autophagy related; BECN1: beclin 1; cfDNA: cell-free DNA; COVID-19: coronavirus disease 2019; CQ: chloroquine; DMVs: double-membrane vesicles; ELANE/NE: elastase, neutrophil expressed; F3: coagulation factor III, tissue factor; HCQ: hydroxychloroquine; MAP1LC3/LC3: microtubule associated protein 1 light chain of 3; MPO: myeloperoxidase; MTORC1: mechanistic target of rapamycin kinase complex 1; NETs: neutrophil traps; NSP: nonstructural protein; PI3K: class I phosphoinositide 3-kinase; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; ROS: reactive oxygen species; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; SKP2: S-phase kinase associated protein 2; TCC: terminal complement complex; ULK1: unc-51 like

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Sarcopenia is defined as an age‐related progressive loss of muscle mass and/or strength. Although different factors can contribute to this disease, the underlying mechanisms remain unclear. We assessed transcriptional heterogeneity in skeletal muscles from sarcopenic and control mice at single‐cell resolution. A mouse model was established to study sarcopenic skeletal muscles. Single‐cell RNA‐seq was performed on tibialis anterior (TA) muscle cells collected from sarcopenic and control mice. A series of bioinformatic analyses were carried out to identify and compare different cell types under different conditions. Immunofluorescence staining and western blotting were used to validate the findings from single‐cell experiments. Tube formation assays were conducted to further evaluate the effects of Gbp2 on endothelial cells during angiogenesis. A murine sarcopenia model was successfully established using a senescence‐accelerated mouse strain (SAMP6, n= 5). Sarcopenia phenotype was induced by administration of dexamethasone (20 mg/kg) and reduced physical activity. Senescence‐resistant mice strain (SAMR1) and SAMP6 strain with similar activity but injected with PBS were recruited as two control groups. As signs of sarcopenia, body weight, muscle cell counts and cross‐sectional fibre area were all significantly decreased in sarcopenic mice (P value = 0.004, 0.03 and 0.035, respectively). After quality control, 13 612 TA muscle single‐cell transcriptomes were retained for analysis. Fourteen cell clusters were identified from the profiled cells. Among them, two distinct endothelial subtypes were found to be dominant in the sarcopenia group (42.2% cells) and in the two control groups (59.1% and 47.9% cells), respectively. 191 differentially expressed genes were detected between the two endothelial subtypes. Sarcopenia‐specific endothelial cell subtype exhibited a dramatic increase in the interferon family genes and the interferon‐inducible guanylate‐binding protein (GBP) family gene expressions. For example, Igtpand Gbp2in sarcopenic endothelial cells were 5.4 and 13.3 times higher than those in the control groups, respectively. We further validated our findings in muscle specimens of sarcopenia patients and observed that GBP2 levels were increased in endothelial cells of a subset of patients (11 of 40 patients, 27.5%), and we identified significantly higher CD31 and GBP2 co‐localization (P value = 0.001128). Finally, we overexpressed Gbp2in human umbilical vein endothelial cells in vitro. The endothelial cells with elevated Gbp2expression displayed compromised tube formation. Our single‐cell‐based results suggested that endothelial cells may play critical roles in sarcopenia development through interferon‐GBP signalling pathways, highlighting new therapeutic directions to slow down or even reverse age‐related sarcopenia.

Catalytic conversion of CO2to CO via reverse water gas shift (RWGS) and CH4via methanation are competing reactions that simultaneously happen on Ni-based catalysts, and selective control of the reactions is of great importance to subsequent applications. Herein, conversion of CO2on Mo3O5/Ni(111) with varying MoOxcoverages was investigated using a combination of density functional theory (DFT) calculation and microkinetic modeling. The overall reaction proceeds through sequential RWGS to CO and CO methanation. The coordinatively unsaturated Mo (Moov) site at the interface of Mo3O5/Ni(111) enhances CO2adsorption and facilitates C–O cleavage over the bare Ni(111), leading to more favorable CO2direct dissociation to CO formation than the carboxyl and formate pathways. The oxophilic Moovalso facilitates hydrogenation of CO to HCO and decomposition of CHO to CH and O. On Mo3O5/4 × 4 Ni(111), the enhanced hydrogenation and C–O breakage activity resulted in CH4as the selective product. On Mo3O5/3 × 3 Ni(111), in contrast, the reduced size of the surface Ni ensembles caused the d-band center of surface Ni sites to shift downward, weakened CO adsorption, and reduced the hydrogenation activity, resulting in CO as the dominant product. Microkinetics analysis revealed that direct CO2dissociation was the dominant path on Mo3O5/4 × 4 Ni(111) and the interfacial sites of Mo3O5/4 × 4 Ni(111) were primarily covered by O and OH. The rate-limiting step on Mo3O5/Ni(111) was the regeneration of Mo3O5. Consistent with the experimental results, the microkinetics also predicts that CH4is selectively produced on Mo3O5/4 × 4 Ni(111) whereas CO is the primary product on Mo3O5/3 × 3 Ni(111).

A range of degradable polyesters have been developed as sustainable alternatives for commercial plastics; however, limitations of composting facilities and uncontrolled degradation in the environment hindered their viability. In this study, biobased itaconic acid was selected as an active site to control the degradation of polyesters. A series of PBXI copolyesters with Mw’s ranging from 4.86 to 8.31 × 104g/mol and high intrinsic viscosities of more than 1.15 dL/g were successfully synthesized without any cross-linking by selecting appropriate reaction conditions, including condensation temperature and vacuum, effective inhibitor, and catalyst. The obtained copolyesters were semicrystalline, and their Tm’s could be regulated from 42.5 to 179.5 °C. They exhibited outstanding elastic modulus (120–598 MPa) and tensile strength (17.9–51.4 MPa) among degradable polymers. Degradation experiments demonstrated that the incorporation of itaconate segments could facilitate both the hydrolysis and enzymatic degradation of polyesters. The state-of-the-art computation and analysis via molecular dynamics (MD) simulations of PBXI–CALB complexes elucidated the enzymatic degradation mechanism. Experimental results proved that, at room temperature, the degradation could be stimulated and regulated by amines without a catalyst and the Mn’s of lactamization products rapidly decreased to less than 5000 g/mol within 24 h. Moreover, the copolymerized structure of copolyesters and solvent factors could influence the aza-Michael addition between amines and itaconate units. This work provides a strategy to synthesize biodegradable copolymers with the potential to undergo controlled and rapid in vivodegradation with outstanding mechanical properties.

We have synthesized and studied the hierarchical self-assembly of high-molar mass polyurethane with periodically alternating aromatic electron-rich donor and electron-poor acceptor groups. Self-assembly in this system arises from the competing roles of π–π stacking from donor–acceptor units and hydrogen bonding among the intervening urethane spacers. Using dynamic light scattering and varying temperatures and concentrations of the polymer in DMF solutions, we find the coexistence of two populations of self-assembly and an unconventional enhanced ordering inside the self-assembled structures at higher temperatures. Our system exhibits the opposite phenomenon of protein denaturation and disorder–order transitions in conventional polymeric systems: both populations of self-assembled structures become more ordered and compact when heated. In addition, these self-assembled structures show a temperature-dependent memory effect. The pathways of temperature dependence of the size of the assembled structures are different between the heating and cooling steps, exhibiting a strong memory effect. These unusual phenomena emerge from the inherent nature of the free energy landscapes associated with the organization of structures in systems with competing energetic and entropic forces, leading to nonequilibrium properties such as memory effects. This work provides new insights into the physical mechanism of entropically regulated hierarchical macromolecule self-assembly with competing interactions encoded in their chemical sequences, with a great potential to formulate a fundamental understanding for the prevention of neurodegenerative diseases that emerge from ill ordering of macromolecules.

This letter focuses on the problem of uplink channel estimation with the reduced fronthaul overhead in cell-free massive multiple-input multiple-output (mMIMO) systems. First, we propose a sub-sampling scheme to reduce the dimension of fronthaul. Then, we exploit the inherent channel sparsity and model the underdetermined channel estimation problem as an off-grid sparse signal recovery problem. Finally, an enhanced sparse Bayesian learning (ESBL) channel estimation algorithm is proposed to refine the sampled grid points and recover the sparse channel iteratively. Simulation results demonstrate that the proposed algorithm achieves a significant reduction on the fronthaul overhead and offers a better channel estimation performance.

Electrodynamic therapy (EDT) has recently emerged as an alternative approach for tumor therapy viathe generation of ROS by platinum (Pt) nanoparticles under electric field. An interesting phenomenon observed during EDT is that the increased on-site concentration of chloride ions is highly beneficial for ROS generation and inhibition efficacy. Here, in this study, nanoclusters (KCC), consisting of potassium chloride (KCl) nanocrystals and amorphous calcium carbonate (CaCO3), were synthesized and integrated with platinum nanoparticles (KCCP). In this system, KCC can dissolve and release calcium and chloride ions within tumor cells. The intracellular chloride ions considerably facilitated ROS generation by Pt nanoparticles under an electric field. More importantly, the excessive calcium ions and ROS formed a cycle of mutual promotion and self-amplification in cells, leading to agitated tumor inhibition, both in vitroand in vivo.

Adhesives that can in situ adhere to substrates and long-term maintain robust adhesion at extremely low temperatures are highly desired in fields such as aerospace, polar regions, and biological industries. Unfortunately, developing such adhesives has been a daunting task so far, as most polymers tend to freeze in such an environment, leading to poor interfacial wetting, serious deformation, and significant fragileness. To address this challenge, a series of poly(dimethylsiloxane)-based polyurea adhesives were synthesized through a non-isocyanate route. This adhesive exhibited exceptional segmental dynamics and toughness at extremely low temperatures, as demonstrated by the continuous evolution of ordered and disordered hydrogen bonds associated with C═O until the test limit of −170 °C and unprecedented bendability in liquid nitrogen (LN, −196 °C). It could adhere firmly and reversibly to various substrates in LN, achieving an in situ adhesion strength of as high as 1.6 MPa on steel. Evenly important, this adhesive exhibited outstanding long-term tolerance in LN with an ultrahigh adhesion strength of 18.3 MPa after 30 days of immersion. Surprisingly, long-persistent phosphorescence lasting for ∼7s was also observed in LN. This study reduced the adhesion temperature of adhesives to −196 °C while enhancing the in situ adhesion strength in LN to the MPa level.

Inspired by natural enzymes, synergy is widely utilized in small molecule recognition and transformation, but has not been fully explored in polymer synthesis. Herein, we present an enzyme-mimicking catalyst design strategy for constructing rigid-flexible binuclear catalysts (RFBCs), aiming to boost the copolymerization of CO2and propylene oxide (PO). The key design strategy of RFBCs is to boost intramolecular synergy by spatial proximity of active sites imposed by rigid skeleton, while a flexible linker affords dynamic interactions of active centers. The optimal catalyst Nap-Al2, featured with rigid naphthalene skeleton grafting two adjacent aluminum porphyrins through soft alkyl chains, exhibits outstanding catalytic performance (5000 h–1) outperforming the previously reported polymeric catalysts (3100 h–1) under similar conditions. Moreover, Nap-Al2exhibits great thermal stability at high temperatures up to 140 °C. A comprehensive catalytic cycle based on dynamic synergy has been proposed, taking into account the key intermediates involved in the copolymerization of CO2/PO. Overall, we present that the construction of RFBCs for designing enzyme-mimicking catalysts is not only suitable for the ROCOP of CO2/PO but also conducive to future investigation for related polymerization processes, such as the ring-opening of lactones.

Polylactic acid (PLA) is a biodegradable thermoplastic polyester produced from natural resources. Because of its brittleness, many tougheners have been developed. However, traditional toughening methods cause either the loss of modulus and strength or the lack of degradability. In this work, we synthesized a biobased and potentially biodegradable poly(butylene 2,5-furandicarboxylate)-b-poly(ethylene glycol) (PBFEG50) copolymer to toughen PLA, with the purpose of both keeping mechanical strength and enhancing the toughness. The blend containing 5 wt % PBFEG50 exhibited about 28.5 times increase in elongation at break (5.5% vs 156.5%). At the same time, the tensile modulus even strikingly increased by 21.6% while the tensile strength was seldom deteriorated. Such a phenomenon could be explained by the stretch-induced crystallization of the BF segment and the interconnected morphology of PBFEG50 domains in PLA5. The Raman spectrum was used to identify the phase dispersion of PLA and PBFEG50 phases. As the PBFEG50 content increased, the interconnected PBFEG50 domains start to separate, but their size increases. Interestingly, tensile-induced cavitation could be clearly identified in scanning electron microscopy images, which meant that the miscibility between PLA and PBFEG50 was limited. The crystallization of PLA/PBFEG50 blends was examined by differential scanning calorimetry, and the plasticizer effect of the EG segment on the PLA matrix could be confirmed. The rheological experiment revealed decreased viscosity of PLA/PBFEG50 blends, implying the possible greener processing. Finally, potential biodegradability of these blends was proved.

Defective silencing of retrotransposable elements has been linked to inflammageing, cancer and autoimmune diseases. However, the underlying mechanisms are only partially understood. Here we implicate the histone H3.3 chaperone Daxx, a retrotransposable element repressor inactivated in myeloid leukaemia and other neoplasms, in protection from inflammatory disease. Loss of Daxx alters the chromatin landscape, H3.3 distribution and histone marks of haematopoietic progenitors, leading to engagement of a Pu.1-dependent transcriptional programme for myelopoiesis at the expense of B-cell differentiation. This causes neutrophilia and inflammation, predisposing mice to develop an autoinflammatory skin disease. While these molecular and phenotypic perturbations are in part reverted in animals lacking both Pu.1 and Daxx, haematopoietic progenitors in these mice show unique chromatin and transcriptome alterations, suggesting an interaction between these two pathways. Overall, our findings implicate retrotransposable element silencing in haematopoiesis and suggest a cross-talk between the H3.3 loading machinery and the pioneer transcription factor Pu.1.

We present a low-cost clinically viable ventilator design, AmbuBox, using a controllable pneumatic enclosure and standard manual resuscitators that are readily available (AmbuBag), which can be rapidly deployed during pandemic and mass-casualty events with a minimal set of components to manufacture and assemble. The AmbuBox is designed to address the existing challenges presented in the existing low-cost ventilator designs by offering an easy-to-install and simple-to-operate apparatus while maintaining a long lifespan with high-precision flow control. As an outcome, a mass-producible prototype of the AmbuBox has been devised, characterized, and validated in a bench test setup using a lung simulator. This prototype will be further investigated through clinical testing. Given the potentially urgent need for inexpensive and rapidly deployable ventilators globally, the overall design, operational principle, and device characterization of the AmbuBox system have been described in detail with open access online. Moreover, the fabrication and assembly methods have been incorporated to enable short-term producibility by a generic local manufacturing facility. In addition, a full list of all components used in the AmbuBox has been included to reflect its low-cost nature.

Coarse-grained molecular dynamics simulations were performed to investigate the mobility of nanoparticles (NPs) embedded in end-linked polymer networks, considering both the entangled and unentangled cases. For the entangled case, where the network strand length Nxis longer than the entanglement length Ne, the strand dynamics exhibits a heavily entangled subdiffusive feature before being restricted within the fluctuation distance dfluctby the permanent cross-links. The dynamics of NPs with size dNPsmaller than the entanglement tube length dTin such network follows the same behavior as that in entangled linear polymers, while for NPs with size comparable to dT, their motion is suppressed by the entanglements. The constraint release of the entanglements would allow the particles to pass through but is slightly restricted by the permanent network junctions. For the unentangled case, where Nx/Ne< 1, the network strands can move only locally with suppressed subdiffusive behavior due to the restrictions imposed by the adjacent network junctions. Consequently, the coupled NP dynamics is also reduced. In addition, when dNPis larger than the strand fluctuation distance dfluct, the NPs are trapped by the network cages and can diffuse at long times through hopping, which is partially masked by the NP thermal fluctuations, as reflected from the NP trajectories. Such hopping fashion of NP motion becomes more apparent with increasing the network confinement ratio before being permanently localized within the network. Increasing the NP–polymer attraction would further hamper the NP mobility. In general, this work provides some insights into understanding how the permanent cross-links affect the network dynamics and thereby the coupled NP mobility.

A stretchable electronic skin (e-skin) requires a durable elastomeric matrix to serve in various conditions. Therefore, excellent and balanced properties such as elasticity, water proof capability, toughness, and self-healing are demanded. However, it is very difficult and often contradictory to optimize them at one time. Here, a polyurethane (BS-PU-3) containing a polydisperse hard segment, hydrophobic soft segment, and a dynamic disulfide bond was prepared by one-pot synthesis. Unlike the normal two-pot reaction, BS-PU-3 obtained through the one-pot method owned a higher density of self-healing points along the main chain and a faster self-healing speed, which reached 1.11 μm/min in a cut-through sample and recovered more than 93% of virgin mechanical properties in 6 h at room temperature. Moreover, a remarkable toughness of 27.5 MJ/m3assures its durability as an e-skin matrix. Even with a 1 mm notch (half of the total width) on a standard dumbbell specimen, it could still bear the tensile strain up to 324% without any crack propagation. With polybutadiene as the soft segment, the shape, microstructure, and conductivity in BS-PU-3 and BS-PU-3-based stretchable electronics kept very stable after soaking in water for 3 days, proving the super waterproof property. An e-skin demo was constructed, and self-healing in pressure sensitivity, mechanical, and electrical properties were verified.

Sentence semantic matching (SSM) is a fundamental research task in natural language processing. Most existing SSM methods take the advantage of sentence representation learning to generate a single or multi-granularity semantic representation for sentence matching. However, sentence interactions and loss function which are the two key factors for SSM still have not been fully considered. Accordingly, we propose a deep neural network architecture for SSM task with a sentence interactive matching layer and an optimised loss function. Given two input sentences, our model first encodes them to embeddings with an ordinary long short-term memory (LSTM) encoder. Then, the encoded embeddings are handled by an attention layer to find the key and important words in the sentences. Next, sentence interactions are captured with a matching layer to output a matching vector. Finally, based on the matching vector, a fully connected multi-layer perceptron outputs the similarity score. The model also distinguishes the equivocation training instances with an improved optimised loss function. We also systematically evaluate our model on a public Chinese semantic matching corpus, BQ corpus. The results demonstrate that our model outperforms the state-of-the-art methods, i.e., BiMPM, DIIN.

The elastic stiffness of the panel zone in diaphragm-through connection between square steel tubular column and H-shaped steel beam subjected to lateral loads is studied in this paper. Through analyzing the deformation mechanism of diaphragm-through connection, the rotation of the panel zone is found to be the superposition of bending deformation of the column and shear deformation of the panel zone. Based on the mechanical model, the computational method of the elastic stiffness of the panel zone in the diaphragm-though connection is developed. To verify the computational method, three cruciform specimens were tested subjected to a set of anti-symmetrical cyclic load at the beam tips. Based on the test results, the developed finite element model is verified and used in the follow-up parametric analysis to check the applicability of the proposed computational method. Key variables involved are the width of column, thickness of column and the height-to-width ratio of the core tube.

Functional polymers such as polyvinylidene fluoride (PVDF) and its copolymers, which exhibit room-temperature piezoelectricity and ferroelectricity in two-dimensional (2D) limit, are promising candidates to substitute hazardous lead-based piezoceramics for flexible nanoelectronic and electromechanical energy-harvesting applications. However, realization of many polymers including PVDF in ultrathin 2D nanostructures with desired crystal phases and tunable properties remains challenging due to ineffective conventional synthesis methods. Consequently, it has remained elusive to obtain optimized piezoelectric performance of PVDF particularly in sub-10 nm regimes. Taking advantage of its high flexibility and easy processing, we fabricate ultrathin PVDF nanoflakes with thicknesses down to 7 nm by using a hot-pressing method. This thermo-mechanical strategy simultaneously induces robust thermodynamic α to electroactive β-phase transformation, with β fraction as high as 92.8% in sub-10 nm flakes. Subsequently, piezoelectric studies performed by using piezoresponse force microscopy reveal an excellent piezoelectric strain of 0.7% in 7 nm film and the highest piezoelectric coefficient (d33) achieved is −68 pm/V for 50 nm-thick nanoflakes, which is 13% higher than the piezoresponse from 50 nm-thick PZT nanofilms. Our results further suggest thickness modulation as an effective strategy to tune the piezoelectric performance of PVDF and affirm its supremacy over conventional piezoceramics especially at nanoscale. This work aims not only to help understand fundamental piezoelectricity of pure PVDF in sub-10 nm regimes but also provides an opportunity to realize other polymer-based 2D nanocrystals.

Abstract Both the hybrid architecture and low precision analog-to-digital converters (ADCs) are considered to alleviate the burden of high power cost and hardware implementation of millimeter wave (mmWave) communication system. Accordingly, the channel estimation issue in wideband mmWave system with finite-bit ADCs becomes even challenging. To address this issue, the non-linear mmWave channel estimation problem is reformulated into a linear sparse signal recovery problem by utilizing the Bussgang decomposition. Then, based on the equivalent linear sparse model, a Bussgang decomposition-based OMP (BD-OMP) algorithm is proposed to both exploit the inherent sparsity of wideband mmWave channel and alleviate the quantization error. Furthermore, we analyze that the actual noise of linear sparse model consists of combined noise and distortion noise, which is related to the number of quantization bits, antennas, and received signal power in a large scale regime. In addition, the terminal condition of BD-OMP algorithm is derived based on the residual difference of two consecutive iterations, where the expectation of residual difference is the variance of the actual noise. Simulation results demonstrate that the proposed approach can significantly reduce the training overhead for estimating wideband mmWave channel with finite-bit ADCs at the receiver. [ABSTRACT FROM AUTHOR]

How to obtain accurate channel state information (CSI) at the transmitter with less pilot overhead for frequency division duplexing (FDD) massive multiple-input multiple-output (MIMO) system is a challenging issue due to the large number of antennas. To reduce the overwhelming pilot overhead, a hybrid orthogonal and non-orthogonal pilot distribution at the base station (BS), which is a generalization of the existing pilot distribution scheme, is proposed by exploiting the common sparsity of channel due to the compact antenna arrangement. Then the block sparsity for antennas with hybrid pilot distribution is derived respectively and can be used to obtain channel impulse response. By employing the theoretical analysis of block sparse recovery, the total coherence criterion is proposed to optimize the sensing matrix composed by orthogonal pilots. Due to the huge complexity of optimal pilot acquisition, a genetic algorithm based pilot allocation (GAPA) algorithm is proposed to acquire optimal pilot distribution locations with fast convergence. Furthermore, the Cramer Rao lower bound is derived for non-orthogonal pilot-based channel estimation and can be asymptotically approached by the prior support set, especially when the optimized pilot is employed. [ABSTRACT FROM AUTHOR]

Fully biobased poly(butylene 2,5-furandicarboxylate)-co-poly(lactic acid)s (PBFLAs) of lactic acid composition from 10% to 40% are synthesized. They are subjected to molecular, thermal, diffractometric, degradable and mechanical characterizations. Thermogravimetric analysis shows that PBFLA are thermally stable at least 350 °C, much higher than PLA. After the incorporation of lactic acid units, both Tmand crystallization rate decrease with respect to homopolymers. X-ray diffraction measurements indicate that no PLA crystal is present during crystallization. All samples perform better barrier properties with respect to PLA, implying potential application in packaging. These samples behave like semicrystalline plastic in the tensile tests. PBFLA copolyesters show Young’s modulus, maximum tensile strength and breakage elongation higher than 1000 MPa, 38 MPa, and 230%, respectively. Such comprehensive mechanical behaviors exceed most biodegradable materials. Lastly, biodegradability could be significantly improved when more than 20% of lactic acid units are introduced into homopolymers.

In this letter, we consider an underlay cognitive radio network in which a secondary transmitter (ST) communicates with a secondary destination (SD) with the aid of multiple cognitive relays, and multiple colluding eavesdroppers attempt to intercept the secondary transmission. Assuming that there is no ST-SD link, one of the cognitive relays is selected to convey the confidential information, while the others cooperate in jamming the eavesdroppers by transmitting artificial noise. Since the eavesdroppers’ channel information state is considered to be absent, two opportunistic relay selection schemes are proposed to enhance the security of the system. We derive novel closed-form expressions for the secrecy outage probability. Simulation results are presented to validate our analysis.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jtcvs.2008.03.028 Byline: Issam Ismail (a), Ruoyu Zhang (a), Kristina Ringe (b), Stefan Fischer (a), Axel Haverich (a) Author Affiliation: (a) Division of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany (b) Department of Radiology, Hannover Medical School, Hannover, Germany Article History: Received 11 March 2008; Accepted 21 March 2008

In order to investigate mechanical properties of L-shaped column composed of concrete-filled square steel tubes (LCFT column) under eccentric compression, LCFT columns were designed and tested. Through two eccentric compression experiments, the failure mode, the curves of loading-displacement for the whole member and the curves of deflection for mono column (single limb of LCFT column) were obtained. Nonlinear finite element analysis was also employed in this investigation, in which thickness of tube flange, connecting plate thickness and diameter of the hole on connecting plate were discussed. According to results of eccentric compression test and finite element analysis, analytical method of bearing capacity of LCFT columns is proposed based on the yielding criterion of the cross-sectional edge stresses. Results of analytical method, finite element analysis and eccentric compression experiment are resistant with each other, and the accuracy of the analytical method in this paper is verified.

Mn4+-activated oxide phosphors La(MgTi)1/2O3(LMT) with far-red emitting were prepared via a sol–gel route. The structures of samples were determined by X-ray diffraction (XRD) and Reitveld refinement. The occupied sites of Mn4+(d3electronic configuration) in host La(MgTi)1/2O3were confirmed by ab initio calculations in which the system has the lower formation energy, stable lattice structure, and strong bonding state as Mn4+enters into Ti site. The luminescent properties of Mn4+-doped samples were investigated; the samples emit far-red light centered at 708 nm with ultraviolet light (345 nm) or blue light (487 nm) excitation. According to the photoluminescence (PL) and excitation (PLE) spectra, the crystal field strength of the Mn4+-occupied environment was estimated. The thermal stability of phosphor was also evaluated through temperature-dependent PL intensity in a heating and cooling cycle process. The emission band is well-matched with the absorption band of phytochrome PFRunder the excitation of light in near-ultraviolet to blue, which suggests that the LMT: Mn4+phosphor has great potential applications in light-emitting diodes (LEDs) for modulating plant growth.

Solar-driven interfacial evaporation is considered an efficient way to get fresh water from seawater. However, the low evaporation rate, surface salt crystallization, and low energy collection of the photothermal evaporation layer limit its further application in an outdoor freshwater field. And the aggregate structure design of the material itself is often ignored in solar-driven water evaporation. Black soil (BS), with a unique soil aggregate structure, is rich in tubular pores, which can be used for multilevel sunlight utilization and good capillary water transport. Based on the extraordinary photothermal properties and pumping capacity of BS, a reasonable unidirectional salt-collecting device is designed, which can realize long-term collection of mineral salts and continuous evaporation of seawater and generate electric energy in the continuous evaporation. Inspired by the unique aggregate structure, the photothermal material doping of halloysite and nigrosin will simulate the generation of this aggregate structure and retain a good water transport effect while obtaining multistage utilization of sunlight. The solar-driven evaporation rate of a nigrosin–halloysite solar steam generator is 1.75 kg m–2h–1under 1 kW m–2mimic solar radiation; it can achieve stable salt leaching-induced voltage generation of 240 mV. This work demonstrates not only a solar evaporator that can continuously achieve desalination but also the design strategy of BS-like aggregate photothermal materials, which promotes the development of low-cost resource recovery and energy generation for practical outdoor seawater desalination.

Biomimetic aggregates have flourished in various fields, particularly in small-molecule catalysis, but their application in polymer synthesis remains understudied. Herein, we propose a strategy for constructing aggregate catalysts based on aggregation-regulating cooperativity to enhance the copolymerization of CO2/propylene oxide (PO). The key design strategy involves constructing polymeric aluminum porphyrin catalysts (PAPCs) with varied stacking modes induced by substituents’ electronic effects, enabling effective modulation of metal synergism. PAPCs with –Cl and –Br substitution exhibit H-aggregates of porphyrin units, leading to a strong metal synergy effect and stability at high temperatures. The H-aggregate catalysts show high activity (TOF > 10,000 h–1) and high selectivity (>98%). Meanwhile, the activity was maintained at a very low catalyst loading ([Al]/PO = 1/100,000), with the number-average molecular weight of the resulting copolymer over 480 kg/mol. Contrarily, −CH3- and −CH2CH3-substituted PAPCs display J-aggregates with a weak metal synergy effect (unstable at a high temperature). The J-aggregate catalysts show low activity (TOF < 2500 h–1) and polymer selectivity (<90%). The present strategy of designing aggregate catalysts provides a new perspective to regulate metal cooperativity, suitable not only for CO2/epoxide or anhydride/epoxide copolymerization but also for lactone ring-opening polymerizations.

Due to its high strength, high modulus, excellent clarity, good biodegradability and biocompatibility, poly(lactic acid) (PLA), a bio-based thermoplastic polyester, has evolved into a competitive commodity material with potential to replace conventional petrochemical-based polymers. However, the wide applications of PLA have been hampered by its native drawbacks, such as low heat distortion temperature (HDT), inherent brittleness and relatively high cost. In recent years, researchers have devoted to breaking above-mentioned bottleneck and attempted to extend the application of PLA. This review will summarize recent work about the modification of PLA, especially focusing on enhancing HDT, toughening and reducing cost.

Fluorogens with aggregation-induced emission (AIEgens) have emerged as a powerful and versatile platform for the development of novel biosensors. In this study, a series of water-soluble fluorescent probes based on tetraphenylethylene (TPE) were designed and synthesized for the detection of monoamine oxidases (MAOs) based on specific interactions between the probes and the proteins. Among the six probes developed, t-TPEMdisplays a significant fluorescence increase upon introduction of MAOs. Of particular significance is that the fluorescence of t-TPEMin the presence of MAO-A is 21-fold higher than other proteins including MAO-B. Lineweaver–Burk plots reveal that t-TPEMacts as an uncompetitive inhibitor of MAO-A with Ki= 17.1 μM, which confirms its good binding affinity toward MAO-A. Furthermore, a cell imaging experiment reveals that t-TPEMis able to selectively monitor the activity of MAO-A which is localized in mitochondria of MCF-7 cells.

Catalytic reduction of CO2with renewable H2to CO via the reverse water gas shift (RWGS) reaction is an attractive approach to recycle CO2and control net emission of CO2to atmosphere. However, low activity and high CH4selectivity at low temperatures limited the practical implementation of the reaction. Herein, Pt-Re/SiO2catalysts with varying amount of Re were prepared with co-impregnation and tested for the RWGS reaction. Characterization results indicated that the oxophilic ReOx(0 ≤ x ≤ 3.5) located in close proximity to Pt particle, modified the surface of Pt by both partial coverage and electronic interaction, resulting in the reduced number of sites for and weakened strength of CO adsorption. At 400 °C, the turnover frequency (2.30 s−1) on the optimal Pt-Re/SiO2catalyst (Pt/Re = 1.91) is 3.9 times higher than that on Pt/SiO2under differential conditions, and the apparent activation energy is lowered. In contrast to Re/SiO2which produces significant amount of CH4, the CO selectivity on Pt-Re/SiO2maintained > 96.2 % under integral conditions. Reaction order analysis revealed that Pt facilitates H2activation whereas the oxophilic ReOxenhances CO2adsorption and activation. The perimeter sites at the Pt/ReOxinterface with a balanced hydrogenation and C-O cleavage properties synergistically improve the RWGS activity while inhibiting CH4production.

Graphene has achieved a great amount of popularity and interest from the science world because of its extraordinary physical, mechanical and thermal properties. Graphene is an allotrope of carbon, having one-atom-thick planar sheets of sp2bonded carbon atoms densely packed in a honeycomb crystal lattice. Many methods to synthesize graphene have been developed over a short period and we believe it is necessary to create a list of the most notable approaches. This article focuses on the methods to synthesize graphene in an attempt to summarize and document advancements in the synthesis of graphene research and future prospects.

Fluorogens with aggregation-induced emission (AIE) characteristics are attracting intense research interest, and an AIE–peptide conjugate strategy has been reported for developing turn-on probes based on hydrophilic peptide ligands. To build a model also suitable for hydrophobic ligands, we propose to fine-tune the AIE characteristics for probe design. In this work, an iconic AIE fluorogen tetraphenylethene (TPE) was designed to conjugate with peptide fragments containing different numbers of aspartic acid (D) units. Relationships between the numbers of D and the hydrophilicity, optical properties, and aggregate sizes and the AIE characteristics of TPE–peptide conjugates were investigated carefully. Five carboxyl groups were found to be the threshold to “turn off” the fluorescence of TPE. As a proof-of-concept, TPE-SS-D5containing a cleavable disulfide bond was synthesized for thiol turn-on detection. The validated tunable AIE characteristic offers new opportunities to design fluorescence turn-on probes based on hydrophobic recognition elements and AIE fluorogens.

A series of N1-substituted 2,4,5-triphenyl imidazole derivatives was designed, synthesized and evaluated for their p53-MDM2 binding inhibitory activities and anti-proliferative activities in vitro against four human cancer cell lines (PC3, KB, A549 and HCT116). Although logical evaluation revealed weak p53-MDM2 binding inhibitory activities, most of the obtained molecules displayed moderate to potent cytotoxicities against tested cell lines. As a potential lead compound for further optimization, compound 9c was evaluated as the most potent compound against four cell lines and could induce cell cycle arrest at G2/M phase. The binding mode of compound 9f and MDM2 was further studied by docking analysis and the unexpected interaction mode revealed that this series of compounds may take part into a different binding modes as the lead compound Such as Nutlin, which could induce a different mechanism in cancer therapy.

It has been a long story of the development of anticancer metallopharmaceuticals since the identification of cisplatin. Advances in metallodrugs discovery during the past 40 years have made it an ever-growing area of research in medicinal inorganic chemistry. Meanwhile, the emerging of N-heterocyclic carbene (NHC) chemistry has stimulated the newly burgeoning interests in the biomedical applications of metal-NHC complexes. This review will detail what have been achieved hitherto in the research of metal-NHC complexes as potential anti-tumor agents coupled with gold, silver, copper, platinum and palladium. Their mechanism of action will also be discussed. All the results obtained indicate that this promising approach is worthy of more focuses and further studies.

A visible-light photocatalytic regioselective [2 + 2 + 1] radical annulation reaction of alkenes, tert-butyl nitrite, and gem-dihalides has been developed. The protocol provides an efficient and practical approach to obtain isoxazolines in good yields under mild conditions. Significantly, gem-dihalides serve as C1 synthons, while cheap tert-butyl nitrite acts as an ideal “N–O” synthon.

New estimations of radiative forcing due to CO2were calculated using updated concentration data of CO2and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing (ARF) due to CO2from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m−2, which was 17% larger than that of the IPCC’s 4th Assessment Report because of the rapid increase in CO2concentrations since 2005. A new formula is proposed to accurately describe the relationship between the ARF of CO2and its concentration. Furthermore, according to the relationship between the ARF and surface temperature change, possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2increases to 1.5, 2, 2.5, 3, 3.5 and 4 times that of the concentration in the year 2008. The result was values of +2.2°C, +3.8°C, +5.1°C, +6.2°C, +7.1°C and +8.0°C respectively, based on a middle-level climate sensitivity parameter of 0.8 K (W m−2)−1. Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios (pulsed and sustained emissions) as a comparison, according to the Absolute Global Temperature change Potential (AGTP) of CO2. Results showed that CO2will likely continue to contribute to global warming if no emission controls are imposed, and the effect on the Earth-atmosphere system will be difficult to restore to its original level.

Combined acute lung injury (ALI) and kidney injury (AKI) is a common problem in critically ill patients. By combining pulmonary (gas exchange) and renal (hemofiltration) support in one extracorporeal device with low-flow resistance, we seek to provide less artificial surfaces maintaining sufficient organ support. Modified Interventional Lung Assist (iLA) Membrane Ventilator (miLA), consisting of polymethylpentene gas exchange membranes and polyethersulfone hemofiltration membranes, was compared in vitrowith the original iLA design, consisting only of gas exchange membranes, regarding both delivery volume and loss in pressure versuspump rate. Efficiency tests concerning gas exchange and hemofiltration rate were performed in vitroand in vivo. In vitroanalyses showed no differences between both systems, with adequate filtration rates in miLA. Anticoagulation and constant blood pressure allowed 1.2 Lmin of blood flow and hemofiltration rates of 70 mlh through miLA in vivo. No major differences between concentrations of filtered molecules in blood and hemofiltrate were found. A stable gas exchange function was maintained. No signs of hemolysis were detected. Our results confirm the feasibility of single-device support for combined pulmonary and renal injury. Novel devices expanding on this concept may potentially improve therapy of critically ill patients with ALIAKI.