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MXene-derived nanostructures provide the possibility of meeting the requirements of strong absorption, thin thickness and flexible layer for electromagnetic (EM) wave absorption. However, exploration of pure and well-intercalated MXene nanosheets for efficient EM wave absorption is still in the nascent stages. Herein, Ti3C2Tx nanosheets with solvent-manipulated properties were achieved via ultrasonication-solvothermal treatment of bulk Ti3C2Tx in different solvents including dimethylformamide (DMF), ethanol, and dimethyl sulfoxide (DMSO), respectively, because of their combined influences of molecular size, oxidation capability, and boiling point. Especially, it was found that a larger layer space and less oxidation effects on the Ti3C2Tx nanosheets were observed upon solvothermal treatment in DMF than those in ethanol or DMSO treatment. As a result, the DMF-treated Ti3C2Tx nanosheets can be used as highly effective dielectric materials for EM wave absorption. The reflection loss value reached −41.9 dB (more than 99.99%) at 13.4 GHz with the sample thickness of only 1.1 mm. Characterization techniques including scanning electron microscopy, transmission electron microscopy, atomic force microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and density functional theory calculation were used to elaborate the possible mechanisms. [ABSTRACT FROM AUTHOR]

Dispersing graphene oxide (GO) in low-polar solvents can realize a perfect self-assembly with functional molecules and application in removal of organic impurities that only dissolve in low-polar solvents. The surface chemistry of GO plays an important role in its dispersity in these solvents. The direct transfer of hydrophilic GO into low-polar solvents, however, has remained an experimental challenge. In this study, we design an interface to transfer GO by simultaneously ‘pushing and pulling’ the nanosheets into low-polar solvents. Our approach is outstanding due to the ability to obtain monolayers of chemically reduced GO (CRGO) with designed surface properties in the organic phase. Using the transferred GO or CRGO dispersions, we have fabricated GO/fullerene nanocomposites and assessed the ability of CRGOs for dye adsorption. We hope our work can provide a universal approach for the phase transfer of other nanomaterials. [ABSTRACT FROM AUTHOR]

Gas sensing for hydrothermal synthesized SnO2-based gas sensors can be enhanced in three ways: structural improvement, composition optimization, and processing improvement. There have been zero-dimensional, one-dimensional, and three-dimensional structures reported in the literature. Controllable synthesis of different structures has been deployed to increase specific surface area. Change of composition would intensively tailor the SnO2 structure, which affected the gas-sensing performance. Furthermore, doping and compounding methods have been adopted to promote gas-sensing performance by adjusting surface conditions of SnO2 crystals and constructing heterojunctions. As for processing area, it is very important to find the optimal reaction time and temperature. In this paper, a gas–solid reaction rate constant was proposed to evaluate gas-sensing properties and find an excellent hydrothermal synthesized SnO2-based gas sensor. [ABSTRACT FROM AUTHOR]

In this paper, the uniformity of polymer film etching by an atmospheric pressure He/O2 microplasma jet array (μPJA) is first investigated with different applied voltage. Plasma characteristics of μPJA were recorded by optical discharge images. Morphologies and chemical compositions of polymer film etched by μPJA were analyzed by optical microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). By increasing the applied voltage from 8.5 kV to 16.4 kV, the non-uniformity of the luminous intensity of the plasma jets increases. It is interesting that the plasma treated regions are actually composed of an etched region and modification region, with distinct morphologies and chemical compositions. The diameters of the etched parylene-C film show the increase of non-uniformity with higher applied voltage. SEM results show that the non-uniformity of surface morphologies of both the modification regions and etched regions increases with the increase of applied voltage. EDS and XPS results also present the significant effect of higher applied voltage on the non-uniformity of surface chemical compositions of both modification and etched regions. The Coulomb interaction of the streamer heads and the hydrodynamic interaction between the plasma jets and the surrounding air are considered to be responsible for this phenomenon. The results shown in this work can help improve the processing quality of polymer film etched by an atmospheric pressure microplasma jet array and two applications are demonstrated to illustrate the uniform downstream surface treatment. [ABSTRACT FROM AUTHOR]

High hydrogen content and long-term stability in aqueous solutions make ammonia-borane (AB) a promising hydrogen-storage material. It is highly attractive but still challenging to develop efficient catalysts for real-time and controllable hydrogen release from AB solution under mild conditions. Herein, we describe the use of a three-dimensional hierarchical Cu(OH)2@Co2CO3(OH)2 core–shell nanowire array on copper foam (denoted as Cu(OH)2@Co2CO3(OH)2/CF) as a highly efficient catalyst for hydrolytic dehydrogenation of AB. The Cu(OH)2@Co2CO3(OH)2/CF works as an on/off switch for on-demand hydrogen generation with a low activation energy of 44.3 KJ mol−1 and a turnover frequency of 39.72 mol(H2)/mol(cat.)/min. It also maintains activity and integration after long-term usage. [ABSTRACT FROM AUTHOR]

In this paper, we present a multiband flexible metamaterial in which one resonance acts as a strain sensor, while the others remain unchanged with bending strain, which might occur due to wrapping around an irregular curved surface. From both experiment and simulation, four transmission dips were observed at around 0.51, 1.34, 1.72 and 1.81 THz, respectively. The results indicated that the resonance dips in the flexible metamaterial arose from the different orders of dipole resonance mode. In the experiment, the frequency shift and amplitude modulation of the transmission at the first resonance increased linearly with the increase of the relative length change Δl/L and changed as an exponential function of the applied bending strain. In addition, the first resonance frequency of the horizontal dipole blue shifted by 6.4 GHz, or about 1.29%, while the relative intensity change of 31.95% in the transmission was achieved when the strain was 2.79‰. This study promises applications in curvature sensing and other controllable metamaterial-based devices. [ABSTRACT FROM AUTHOR]

We report experimental results on the effects of laser contrast on beam divergence and energy spectrum of protons emitted from ultrashort intense laser interactions with normal large foils and transverse-size-reduced targets. Correlations between beam divergence and spectral shape are found. Large divergence and near-plateau shape energy spectrum are observed for both types of targets when the laser pulse contrast is low. With high contrast laser irradiation, proton beam divergence is remarkably reduced and the energy spectral shape is changed to exponential for large foil targets. In comparison, a similar large divergence and the near-plateau spectral shape remain for transverse-size-reduced targets. The results could be explained by the preplasma formation and target deformation at different laser contrasts and modified accelerating sheath field evolution in transverse-size-reduced target, which were supported by the 2D hydrodynamic and PIC simulations. [ABSTRACT FROM AUTHOR]

The optimization of the laser micromachining process for special tapered micropipettes was investigated using response surface methodology. Three process parameters for the CO2 laser-based micropipette puller (P-2000, Sutter Instrument) were chosen as variables, namely heat, velocity and pull. The targeted length LTVS of the tapered variant section with a tip diameter of 10 μm was taken as a response. The optimum process parameters with LTVS of 7.3 mm were determined by analyzing the response surface three-dimension surface plots. The central composite design was selected to optimize the process variables, and the experimental data were fitted into a reduced cubic polynomial model. The high R2 value (99.66%) and low coefficient of variation (0.73%) indicated the statistical significance of the model and good precision for the experiment. The optimization result showed that the best parameters were with the heat, velocity and pull values of 850, 53 and 170, respectively. The result was verified by a CO2 laser-based micropipette puller three times with length LTVS at 7.26 mm, 7.35 mm and 7.36 mm with the same optimized parameters. Then, the application to the ultrafine atmospheric pressure He/O2 plasma jets was carried out and micro-hole etching of the parylene-C film was realized with length LTVS at 6.29 mm, 7.35 mm and 8.02 mm. The results showed that the micro-plasma jet with an LTVS of 7.35 mm had the minimum applied voltage of 12.7 kV and the minimum micro-etching diameter of 45 μm with the deepest etching depth of 2.8 μm. [ABSTRACT FROM AUTHOR]

Proton emission from solid foil targets irradiated by relativistically intense femtosecond laser pulses is studied experimentally. Broad plateaus in energy spectra are measured from micron-thick targets when the incident laser pulses have relatively low intensity contrasts. It is proposed that such proton spectra can be attributed to the combined processes of laser-driven collisionless shock acceleration and target normal sheath acceleration. Simple analytic estimation and two-dimensional particle-in-cell simulations are performed, which support our interpretation. The obtained plateau-shape spectrum may also serve as an effective tool to diagnose the plasma state and verify the ion acceleration mechanisms in laser-solid interactions. [ABSTRACT FROM AUTHOR]

Copper is a good dielectric loss material but has low stability, whereas nickel is a good magnetic loss material and is corrosion resistant but with low conductivity, therefore Cu–Ni hybrid nanostructures have synergistic advantages as microwave absorption (MA) materials. Different Cu/Ni molar ratios of bimetallic nanowires (Cu13@Ni7, Cu5@Ni5 and Cu7@Ni13) and nanospheres (Cu13@Ni7, Cu5@Ni5 and Cu1@Ni3) have been successfully synthesized via facile reduction of hydrazine under similar reaction conditions, and the morphology can be easily tuned by varying the feed ratio or the complexing agent. Apart from the concentrations of Cu2+ and Ni2+, the reduction parameters are similar for all samples to confirm the effects of the Cu/Ni molar ratio and morphology on MA properties. Ni is incorporated into the Cu–Ni nanomaterials as a shell over the Cu core at low temperature, as proved by XRD, SEM, TEM and XPS. Through the complex relative permittivity and permeability, reflection loss was evaluated, which revealed that the MA capacity greatly depended on the Cu/Ni molar ratio and morphology. For Cu@Ni nanowires, as the molar ratio of Ni shell increased the MA properties decreased accordingly. However, for Cu@Ni nanospheres, the opposite trend was found, that is, as the molar ratio of the Ni shell increased the MA properties increased. [ABSTRACT FROM AUTHOR]

A direct-write process device based on the atmospheric pressure air microplasma jet (AμPJ) has been developed for the localized etching of polymer films. The plasma was generated by the air discharge ejected out through a tip-nozzle (inner diameter of 100 μm), forming the microplasma jet. The AμPJ was capable of reacting with the polymer surface since it contains a high concentration of oxygen reactive species and thus resulted in the selective removal of polymer films. The experimental results demonstrated that the AμPJ could fabricate different microstructures on a parylene-C film without using any masks or causing any heat damage. The etch rate of parylene-C reached 5.1 μm min−1 and microstructures of different depth and width could also be realized by controlling two process parameters, namely, the etching time and the distance between the nozzle and the substrate. In addition, combining XPS analysis and oxygen-induced chemical etching principles, the potential etching mechanism of parylene-C by the AμPJ was investigated. Aside from the etching of parylene-C, micro-holes on the photoresist and polyimide film were successfully created by the AμPJ. In summary, maskless pattern etching of polymer films could be achieved using this AμPJ. [ABSTRACT FROM AUTHOR]

π-π stacking interactions, as a kind of attractive and nondestructive noncovalent interaction, have been widely explored for the applications in modern chemistry, molecular biology, and supramolecular armamentarium, among which their bioapplications have attracted tremendous attention due to the unique advantages such as strong binding force, nondestructive fabrication process, and simple operation. Impressively, great achievements have been made in the area of nucleobase stacking, biosensing, controlled drug release, protein folding, molecular recognition, self-assembly, template-directed synthesis. etc. In this review, we first discuss the characterization, geometric configurations, and requirements for π-π stacking interactions, and then focus on their typical bioapplications in material engineering in particular. At the end, the outlook for potential applications of π-π stacking interactions is also discussed. [ABSTRACT FROM AUTHOR]

Constructing highly porous structures using Ti3C2Tx MXene provides a promising strategy toward achieving low density, high specific surface area, and shorter ion/molecule transport paths. However, the weak MXene-MXene or MXene-substrate interactions hinder the development of ultra-robust and elastic MXene-based architectures. To address this issue, a bio-inspired strategy is developed to effectively adhere the MXene nanosheets onto melamine foam via covalent and hydrogen bonding interactions through polyethyleneimine/polydopamine-modification. The enhanced interactions contribute to high MXene loading (≈94 wt.%) and reversible compressibility even after 10 000 compression/release cycles at 80% strain. The compressible supercapacitor device assembled from this foam exhibits high energy storage capability (119 F g-1 at 2 mV s-1) with capacitance retention of ≈93% after 1000 compression/release cycles at 50% strain. Moreover, the presence of polydopamine and MXene enable the absorption of light in the UV-Vis and near-IR regions, respectively, inducing photothermal conversion functionality, with an evaporation rate of ≈1.5 kg m-2 h-1 and ≈89% solar evaporation efficiency under one sun illumination. It is envisaged that this bio-inspired chemical modification offers a versatile strategy for the assembly of MXene nanosheets onto different substrates for various applications, such as electromagnetic interference shielding, energy storage, and conversion. [ABSTRACT FROM AUTHOR]

The article focuses on a study which presents the fabrication of thermo-sensitive surface graphene-copolymer nanocomposites via π-π stacking. It notes that graphene with controllable low critical solution temperature (LCST) was modified via π-π stacking using thermal sensitive copolymers. It mentions that the scanning electron microscopy (SEM) shows the transparency of graphene-polymer platelets and polymeric properties counld be imparted via surface modification.

An abstract of the study "Quantitative Features of Myoelectric Signals in the Orbicularis Oculi Muscle During Different Motion States," by Dongyue Xu et al. is presented.

An abstract of the research "Artificial facial nerve reflex restores eyelid closure following orbicularisoculi muscle denervation," by Keyong Li, Dongyue Xu, Yuefeng Rui et al, is presented.

Focused ion beam (FIB) was employed to fabricate nanoimprint lithography stamps. Complex micro/nanopatterns were fabricated in the stamp, including curved nanograting structures. These micro/nanostructures were then replicated to SU-8 2000.1 resist, with an imprint temperature of 95 °C, which is lower than for conventional imprint polymers. Atomic force microscopy was used to characterize the surface profiles of stamp and replica’s and the replication fidelity as well. The results show that nanoimprint with the FIB fabricated stamp can successfully replicate complex micro/nanostructures under low temperature in SU-8. [ABSTRACT FROM AUTHOR]

Biotechnology, biomedicine, and nanotechnology applications would benefit from methods generating well-defined, monodisperse protein-polymer conjugates, avoiding time-consuming and difficult purification steps. Herein, we report the in situ synthesis of protein-polymer conjugates via reversible addition-fragmentation chain transfer polymerization (RAFT) as an efficient method to generate well-defined, homogeneous protein-polymer conjugates in one step, eliminating major postpolymerization purification steps. A water soluble RAFT agent was conjugated to a model protein, bovine serum albumin (BSA), via its free thiol group at Cys-34 residue. The conjugation of the RAFT agent to BSA was confirmed by UV- visible spectroscopy, matrix-assisted laser desorption ionization - time of flight (MALDI-TOF), and ¹H NMR. BSA-macroRAFT agent was then used to control the polymerization of two different water soluble monomers, N-isopropylacrylamide (NIPAAm) and hydroxyethyl acrylate (HEA), in aqueous medium at 25 °C. The growth of the polymer chains from BSA-macroRAFT agent was characterized by size exclusion chromatography (SEC), ¹H NMR, MALDI-TOF, and polyacrylamide gel electrophoresis (PAGE) analyses. The controlled character of the RAFT polymerizations was confirmed by the linear evolution of molecular weight with monomer conversion. The SEC analyses showed no detectable free, nonconjugated polymer formation during the in situ polymerization. The efficiency of BSA-macroRAFT agent to generate BSA-polymer conjugates was found to be ca. 1 by deconvolution of the SEC traces of the polymerization mixtures. The structural integrity and the conformation-related esterase activity of BSA were found to be unaffected by the polymerization conditions and the conjugation of the polymer chain. BSA-poly(NIPAAm) conjugates showed hybrid temperature-dependent phase separation and aggregation behavior. The lower critical solution temperature values of the conjugates were found to increase with the decrease in molecular weight of poly(NIPAAm) block conjugated to BSA. [ABSTRACT FROM AUTHOR]

The article presents a study that explores the self-adaptive cardiac optogenetics device based on negative stretching-resistive strain sensor. It demonstrates the potential of a negative stretching-resistive device in controlling-in-sensor electronics for wearable/ implantable autodiagnosis and telehealth applications.

The energy band attraction (EBA) caused by the nonorthogonal eigenvectors is a unique phenomenon in the non-Hermitian (NH) system. However, restricted by the required tight-binding approximation and meticulously engineered complex potentials, such an effect has never been experimentally demonstrated before. Here by a suitable design of all-dielectric Mie resonators in a parallel-plate transmission line, we for the first time verify the photonic analog of the EBA effects both theoretically and experimentally. The evolution of the EBA effect in a two-level NH system from gapped bands to gapless bands to flat bands is observed by precisely tuning the loss of the Mie resonators. The transmission spectra can be theoretically connected to the eigenvalues and eigenvectors of the NH Hamiltonian. Furthermore we extend our methods to a graphenelike two-dimensional NH system. Our works show a metamaterial approach toward NH topological photonics and foster a deeper understanding of band theory in open systems. [ABSTRACT FROM AUTHOR]

This letter presents a high performance bimorph piezoelectric MEMS harvester with bulk PZT thick films on both sides of a flexible thin beryllium-bronze substrate via bonding and thinning technologies. The upper and lower PZT layers are thinned down to about 53 μm and 76 μm, respectively, and a commercial beryllium bronze with the thickness of about 50 μm is used as the substrate. The effective volume of this device is 30.6mm3. The harvester with a tungsten proof mass generated the close-circuit peak-to-peak voltage of 53.1 V, the output power of 0.979 mW, and the power density of 31.99 mW/cm3 with the matching load resistance of 360 kΩ at the applied acceleration amplitude of 3.5 g and the applied frequency of 77.2 Hz. Meanwhile, in order to evaluate the stability, the device was measured continuously under applied acceleration amplitudes of 1.0 g and 3.5 g for one hour and demonstrated a good stability. Then, the harvester was utilized to light up LEDs and about twenty-one serial LEDs were lighted up at resonance under an applied acceleration amplitude of 3.0 g. [ABSTRACT FROM AUTHOR]

Investigates the electron transfer properties of redox enzymes attached to carbon nanotubes. Summary of the electrode fabrication; Modification of the electrode with oxidatively shortened pyrolytic graphite; Evidence of the representation of aligned bundles of nanotubes.

Porous microspheres of regenerated cellulose with size in range of 1-2 µm and composite microspheres of chitosan coated cellulose with size of 1-3 µm were obtained through a two-step spray-assisted approach. The spray coagulating process must combine with a spray drying step to guarantee the formation of stable microspheres of cellulose. This approach exhibits the following two main virtues. First, the preparation was performed using aqueous solution of cellulose as precursor in the absence of organic solvent and surfactant; Second, neither crosslinking agent nor separated crosslinking process was required for formation of stable microspheres. Moreover, the spray drying step also provided us with the chance to encapsulate guests into the resultant cellulose microspheres. The potential application of the cellulose microspheres acting as drug delivery vector has been studied in two PBS (phosphate-buffered saline) solution with pH values at 4.0 and 7.4 to mimic the environments of stomach and intestine, respectively. [ABSTRACT FROM AUTHOR]

Mesoporous composite particles of carbon inlaid with Fe3O4 nanoparticles (designated as Fe3O4@carbon) with a novel bowl structure and magnetic separation property were fabricated by a spray drying assisted template method using chitosan as carbon precursor and silica nanoparticles as pore directing agent. The influence of the contents among Fe3O4 nanoparticles, chitosan and silica nanoparticle on the formation of porous Fe3O4@carbon composite particles has been discussed. Ag nanoparticles were then deposited onto the surface of mesoporous Fe3O4@carbon substrates using silver acetate as precursor with the assistance of ultrasound treatment. The matrices of Ag nanoparticles decorated Fe3O4@carbon composite particles (denoted as Ag--(Fe3O4@carbon)) were derived and characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy, nitrogen adsorption--desorption, and magnetic property measurements. The Ag--(Fe3O4@carbon) composites showed efficient antibacterial activities to Escherichia coli and Staphylococcus aureus, high catalytic activity to the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4, strong adsorption ability to organic molecules, and efficient separability under a magnetic field. [ABSTRACT FROM AUTHOR]

The article pressents an analysis of the bioapplications of reversible addition-fragmentation chain transfer (RAFT) polymerization in various researches. It examines the potential of RAFT in designing novel polymeric structure through RAFT as it is argued to be clearly huge. It reviews the applicability of such polymerization in biomaterials, gene therapy, glycopoylmers, drug delivery systems, and in hybrid organic and inorganic particles.

Abstract  This paper presents a micro electromagnetic energy harvester which can convert low level vibration energy to electrical power. It mainly consists of an electroplated copper planar spring, a permanent magnet and a copper planar coil with high aspect ratio. Mechanical simulation shows that the natural frequency of the magnet-spring system is 94.5 Hz. The resonant vibration amplitude of the magnet is 259.1 μm when the input vibration amplitude is 14 μm and the magnet-spring system is at resonance. Electromagnetic simulation shows that the linewidth and the turns of the coil influence the induced voltage greatly. The optimized electromagnetic vibration energy harvester can generate 0.7 μW of maximal output power with peak–peak voltage of 42.6 mV in an input vibration frequency of 94.5 Hz and input acceleration of 4.94 m/s2 (this vibration is a kind of low level ambient vibration). A prototype (not optimized) has been fabricated using MEMS micromachining technology. The testing results show that the prototype can generate induced voltage (peak–peak) of 18 mV and output power of 0.61 μW for 14.9 m/s2 external acceleration at its resonant frequency of 55 Hz (this vibration is not in a low ambient vibration level). [ABSTRACT FROM AUTHOR]

Acute gastrointestinal injury (AGI) is common in mechanically ventilated (MV) patients, but the potential association between ventilatory pressure parameters and AGI grade and their impact on mortality remains unclear. This study aimed to explore the association between ventilatory pressure parameters and AGI grade, and their interaction on all-cause mortality in MV patients. This study was a secondary analysis of a multicenter, prospective, observational study that enrolled adult patients with an expected duration of mechanical ventilation ≥ 48 h from 14 general intensive care units in Zhejiang Province between March and August 2014. The AGI grade was assessed daily on the basis of gastrointestinal symptoms, intra-abdominal pressures, and feeding intolerance in the first week of admission to the ICU. This study included 331 patients (69.2% men; mean age, 64.6 ± 18.9 years). Multivariate regression analysis showed that plateau pressure (Pplat) (OR 1.044, 95% CI 1.009-1.081, P = 0.013), serum creatinine (OR 1.003, 95% CI 1.001-1.006, P = 0.042) and APACHE II score (OR 1.035, 95% CI 1.021-1.072, P = 0.045) were independently associated with global AGI grade III/IV within 7 days of ICU admission. Moreover, global AGI grade (HR 2.228, 95% CI 1.561-3.182, P < 0.001), serum creatinine (HR 1.002, 95% CI 1.001-1.003, P = 0.012) and APACHE II score (HR 1.039, 95% CI 1.015-1.063, P = 0.001) were independently associated with 60-day mortality. In addition, there were significant (P int  ≤ 0.028) interactions of Pplat and DP with AGI grade in relation to 60-days mortality, whereas no interaction (P int  = 0.061) between PEEP and AGI grade on 60-days mortality was observed. In the presence of Pplat ≥ 19 cmH 2 O, the patients with AGI grade III/IV had 60-day mortality rate of 72.2%, significantly higher than those with AGI grade I/II (48.7%, P = 0.018), whereas there were no significant differences (27.9% vs. 33.7%, P = 0.39) in 60-days mortality between AGI grade I/II and III/IV among the patients with Pplat < 19 cmH 2 O. In comparison with Pplat, DP had a similar interaction (P int  = 0.028) with AGI grade on 60-day mortality. Ventilatory pressure parameters (Pplat and DP) are independent risk factors of AGI grade III/IV. Pplat and DP interact with AGI grade on 60-days mortality, highlighting the importance of optimizing ventilatory pressure parameters to improve gastrointestinal function and survival outcomes of MV patients.Trial registration: ChiCTR-OCS-13003824., (© 2024. The Author(s).)