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•Activation had the influence on properties of carbon-based solid acid catalysts.•Non-activated, KOH-activated, ZnCl2-activated treatments were comparatively discussed.•Activated ...improved the specific surface area and functional groups of catalysts.•Non-activated catalysts were conductive to produce furfural from xylose.•KOH-activated catalysts were beneficial to produce XOS from hemicellulose.
Activation plays an important role in improving the pore structure of the carbon materials preparation. For carbon-based solid catalysts, activation could provide the high specific surface area and porosity. In this work, non-activated, KOH-activated, ZnCl2-activated treatments were comparatively discussed to prepare carbon-based solid acid catalysts for furfural production from xylose and hemicelluloses. These prepared catalysts were characterized by SEM, FT-IR, elemental analysis, Raman, N2 adsorption-desorption and Boehm titration. The results showed that the chemical activated treatment could significantly improve the specific surface area of carbon-based solid catalysts, but also had an important influence on the distribution of surface functional groups especially for decreasing of the SO3H density and the enhancement of the phenolic OH and COOH density. For the highest SO3H density of non-activated carbon-based catalyst, it displayed higher catalytic activity in the conversion of xylose to furfural than other catalysts. Meanwhile, using non-activated carbon-based catalyst in the aqueous solution, the maximum furfural yield of 50% was obtained from hemicelluloses at 200 °C for 2.5 h, the maximum xylose yield of 55% was achieved at 200 °C for 1.5 h. While KOH-activated carbon-based catalyst exhibited the excellent catalytic performance to produce xylooligosaccharide with the highest yield of 62% at 180 °C for 1.5 h.
Terbium doped graphitic carbon nitride (g-C
3
N
4
:Tb) gives rise to two exceptional emissions at
λ
ex
/
λ
em
= 290/490 nm and 290/546 nm, with extremely narrow peak widths of FWHM < 12 nm as well as ...a large Stokes shift of >200 nm. The modification of g-C
3
N
4
:Tb with HOOC-PEG-COOH provides a ratiometric fluorescent probe which ensures highly sensitive detection of alkaline phosphatase (ALP) activity based on the inner filter effect (IFE).
Terbium doped g-C
3
N
4
produces two exceptional emissions with extremely narrow peaks with FWHM < 12 nm and a large Stokes shift of >200 nm. Its modification with HOOC-PEG-COOH endows a ratiometric fluorescence sensitive assay of alkaline phosphatase.
To better understand the mechanical properties and influence mechanism of hydroxyl‐terminated polybutadiene (HTPB) propellant under various confining pressures, the uniaxial tension tests with low to ...medium strain rate and various confining pressures were carried out. The coupling effects of strain rate and confining pressure on mechanical properties were presented. Meanwhile, the confining pressure influence mechanism was analyzed and revealed using the meso numerical simulation method and scanning electron microscopy images of fracture surfaces. The meso damage evolution processes under various confining pressures were presented. The results show that strain rate and confining pressure affect mechanical responses of HTPB propellant significantly. As confining pressure increases, the maximum tension strength and fracture strength increase. The maximum tension strain and failure strain vary slightly with confining pressure under low strain rate, while they increase significantly with confining pressure at medium strain rate. The fracture energy density increases with the increase of strain rate and confining pressure. Meanwhile, the value of saturation pressure depends on strain rate. The confining pressure influence mechanism is to suppress dewetting damage initiation and evolution. Besides, the failure mode of HTPB propellant under different confining pressures is still particles dewetting.
The coupling effects of confining pressure and strain rate on the mechanical properties of HTPB propellant were studied. The confining pressure influence mechanism was revealed using meso numerical simulation method.
The gut microbiota plays an integral role in the metabolism and immunity of animal hosts, and provides insights into the health and habitat assessment of threatened animals. The skywalker hoolock ...gibbon (Hoolock tianxing) is a newly described gibbon species, and is considered an endangered species. Here, we used 16S rRNA amplicon sequencing to describe the fecal bacterial community of skywalker hoolock gibbons from different habitats and in captivity. Fecal samples (n = 5) from two captive gibbons were compared with wild populations (N = 6 gibbons, n = 33 samples). At the phylum level, Spirochetes, Proteobacteria, Firmicutes, Bacteroidetes dominated in captive gibbons, while Firmicutes, Bacteroidetes, and Tenericutes dominated in wild gibbons. At the genus level, captive gibbons were dominated by Treponema-2, followed by Succinivibrio and Cerasicoccus, while wild gibbons were dominated by Anaeroplasma, Prevotellaceae UCG-001, and Erysipelotrichaceae UCG-004. Captive rearing was significantly associated with lower taxonomic alpha-diversity, and different relative abundance of some dominant bacteria compared to wild gibbons. Predicted Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that captive gibbons have significantly lower total pathway diversity and higher relative abundance of bacterial functions involved in "drug resistance: antimicrobial" and "carbohydrate metabolism" than wild gibbons. This study reveals the potential influence of captivity and habitat on the gut bacterial community of gibbons and provides a basis for guiding the conservation management of captive populations.
Cost-effective and earth-abundant oxygen evolution reaction (OER) electrocatalysts are an incredible research hotspot in numerous energy storage and conversion technology fields. Herein, CoS2/MoS2 ...nanosheets supported by carbon cloth as a dual-active CC@CoS2/MoS2 heterostructure electrocatalyst is prepared through a simple solvothermal method. The catalyst demonstrates admirable OER performance in 1 M KOH solution with a low overpotential of 243 mV at a current density of 10 mA cm–2 and a minor Tafel slope of 109 mV dec–1, displaying honorable stability after 1000 cyclic voltammetry (CV) cycles and long-term robustness over 60 h. Theoretical calculations further ascertain that the rate-determining step of the electrocatalytic course of the CC@CoS2/MoS2 heterostructure is the conversion *O + OH– → *OOH + e– with a lower energy barrier of 1.49 eV due to the heterojunction established by CoS2 and MoS2, which can promote the OER performance of electrocatalysts. The actual identification of the catalytic mechanism in the heterostructure is conducive to the improvement of electrocatalysis applications in the OER.
Mechanical nociception is an evolutionarily conserved sensory process required for the survival of living organisms. Previous studies have revealed much about the neural circuits and sensory ...molecules in mechanical nociception, but the cellular mechanisms adopted by nociceptors in force detection remain elusive. To address this issue, we study the mechanosensation of a fly larval nociceptor (class IV da neurons, c4da) using a customized mechanical device. We find that c4da are sensitive to mN-scale forces and make uniform responses to the forces applied at different dendritic regions. Moreover, c4da showed a greater sensitivity to localized forces, consistent with them being able to detect the poking of sharp objects, such as wasp ovipositor. Further analysis reveals that high morphological complexity, mechanosensitivity to lateral tension and possibly also active signal propagation in dendrites contribute to the sensory features of c4da. In particular, we discover that Piezo and Ppk1/Ppk26, two key mechanosensory molecules, make differential but additive contributions to the mechanosensitivity of c4da. In all, our results provide updates into understanding how c4da process mechanical signals at the cellular level and reveal the contributions of key molecules.
Automatic Modulation Classification (AMC), which based on deep learning has been extensively researched and implemented in wireless communication systems. Universal adversarial perturbation refers to ...a single perturbation that can cause most samples to be misclassified by deep learning models. In this brief, we aim to achieve imperceptible universal adversarial attacks on AMC models, and thus an imperceptible universal adversarial perturbations (imperceptible UAPs) framework was proposed. Specifically, loss functions were separately designed for target signals and non-target signals, and then a total loss was calculated. This total loss function can be modified by hyperparameters to achieve class-specific universal adversarial attacks (CUAAs), class-discriminative universal adversarial attacks (CD-UAAs), and class-discriminative target universal adversarial attacks (CD-TUAAs). Meanwhile, wavelet reconstruction was applied to the training data, thus further improving the discriminability of the generated UAPs. After CUAAs were implemented, the class dominant in radio signals was visualized and analyzed by confusion matrices. Furthermore, with the confusion matrices of CUAAs, CD-TUAAs were efficiently implemented. The experiments were conducted on two radio signal datasets and models. In most scenarios, CD-UAAs achieved excellent performance with an average <inline-formula> <tex-math notation="LaTeX">\Delta A_{c c} </tex-math></inline-formula> of 58. 20% and CD-TUAAs achieved an average <inline-formula> <tex-math notation="LaTeX">\Delta K </tex-math></inline-formula> of 73.78%.
In this study, CuS@PDA nanoparticles were synthesized and used to create a novel tumor-targeting nanocomposite platform composed of copper sulfide@polydopamine-folic acid/doxorubicin (CuS@PDA-FA/DOX) ...for performing both photothermal and chemotherapeutic cancer treatment. The nanocomposite platform has ultrahigh loading levels (4.2 ± 0.2 mg mg
−1
) and a greater photothermal conversion efficiency (
η
= 42.7%) than CuS/PDA alone. The uptake of CuS@PDA-FA/DOX nanocomposites is much higher in MCF-7 cells than in A549 cells because MCF-7 cells have much higher folic acid receptors than A549. Under near infrared (NIR) irradiation, the CuS@PDA-FA/DOX system using a synergistic combination of photothermal therapy and chemotherapy yields a better therapeutic effect than either photothermal therapy or chemotherapy alone. The treatment is very effective with the cell viability is only 5.6 ± 1.4%.
CuS@PDA nanoparticles were synthesized and used to create a novel tumor-targeting nanocomposite platform composed of copper sulfide@polydopamine-folic acid/doxorubicin for performing both photothermal and chemotherapeutic cancer treatment.
This brief focuses on the dynamic weighted average consensus problem and aims to achieve accurate tracking of the weighted average of all the time-varying reference signals in a network. We first ...propose a robust dynamic weighted average consensus (RDWAC) algorithm that employs a simple fixed control gain and introduces an individual weight for each agent compared with recent works. Furthermore, a theoretical finite-time convergence analysis instead of an asymptotic one is provided by constructing a novel Lyapunov function, which shows that the accurate weighted average consensus can be reached exponentially within a finite time interval. In addition, the lower bound of the required convergence time is given and the relationship between the lower bound and the initial steady-state error and control parameters is established explicitly. Finally, some numerical examples are given to illustrate the effectiveness of the proposed algorithm.
Titanium (Ti)-based alloys are eye-catching biomaterials extensively utilized in human implants due to their outstanding ability to facilitate cell growth. This research aims to propose a new ...approach to explore the ultrafast laser processing on alloy surfaces for achieving and regulating the proliferation of biological cells. The study is to directly use the polarization of ultrafast laser irradiation on the surface of chromium-titanium nitride (CrTiN) thin film to fabricate the periodic structures, which can promote cell proliferation. This improvement is accomplished by employing surface patterning and creating nanocrystalline structures. The nanocrystalline layer is treated with laser-induced periodic surface structures (LIPSS), forming subwavelength ripples directly on the surface. The ripples are preferentially formed perpendicular to the direction of laser polarization by controlling the fluence. Through the straightforward technique of ultrafast laser treatment, the wettability transition is contributed to by the combination of LIPSS and modified surface chemistry. It is indicated by the findings that the laser-irradiated CrTiN alloy film exhibits surface ripples and a nanocrystalline phase. This work has the potential to enhance cell proliferation for biomedical engineering applications.
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