Spatial electromagnetic (EM) radiation, big data, is both an opportunity and a challenge. Harvesting and converting waste EM energy for high‐efficient recycling has a huge significance in the energy ...field. Herein, a new and effective patching engineering method using conductive polymers to repair magnetic graphene (NF‐P) is proposed, tailoring the microstructure network controllably, including conductive network and relaxation genes. It realizes the precise tuning of EM property, and the EM response shows a significant increase of 52%. The energy transformation inside materials is surveyed, and a revolutionary mode of energy conversion is constructed, ingeniously utilizing the stored electrical energy and the converted heat energy inside the material with the theoretical utilization of absorbed EM energy up to 100%. The NF‐P patching network serves as a prototype for a potential cell device with the EM energy conversion improved by ≈10 times and effective bandwidth increased by 13 GHz that covers the entire research frequency band (2–18 GHz). This research opens up a new idea for energy utilization inside materials, providing a novel and effective path for harvesting, converting and delivering spatial EM energy.
Energy is not produced, but is simply portered. Here, a revolutionary prototype cell is constructed, ingeniously utilizing the stored electrical energy and converted heat energy inside material with the theoretical utilization of absorbed electromagnetic energy up to 100%.
Research Advances in Microfiber Humidity Sensors Peng, Yun; Zhao, Yong; Chen, Mao‐Qing ...
Small (Weinheim an der Bergstrasse, Germany),
July 19, 2018, Letnik:
14, Številka:
29
Journal Article
Recenzirano
An overview of the numerous latest research in microfiber humidity sensors is carried out with a specific focus on measurement methods, humidity sensitive materials, probe structures, and sensing ...properties of different sensors. First, five mainstream measurement structures, including taper, fiber grating, coupler, resonator, and interferometer are reviewed. It is concluded that these measurement structures sense the physicochemical property variations of microfibers or sensitive films and exhibit the change of optical signal when exposed to environment. Second, the basic preparation methods, humidity‐sensing properties, and their advantages and disadvantages as humidity sensitive material are addressed. Then, the advantages and disadvantages of all the above sensing structures are also discussed and compared. Finally, the main existing problems and potential solutions of microfiber humidity sensors are pointed out.
The development of microfiber humidity sensors is highlighted. Different measurement methods relying on taper, fiber grating, coupler, resonator, and interferometer are determined and then the sensitive materials used in microfiber humidity sensors are proposed. The advantages and disadvantages for each measurement method are also discussed. Finally, the existing problems and future research directions are outlined.
•A novel optic fiber Fabry-Perot interferometer based on GQDs and Polyvinyl Alcohol is first proposed for RH sensing.•The GQDs-PVA compounds are filled to the hollow core fiber, which is spliced at ...the end of a single mode fiber.•Experiment results reveal that sensitivity is 117.25 pm/%RH with the RH changing from 13.47%RH to 81.34%RH.•The linearity relevancy of proposed sensor is 0.9983.
A novel optic fiber Fabry-Perot interferometer (FPI) based on graphene quantum dots (GQDs) and Polyvinyl Alcohol (PVA) is first proposed for relative humidity (RH) sensing and experimentally demonstrated. The GQDs-PVA compounds are filled into the hollow core fiber (HCF), which is spliced at the end of a single mode fiber (SMF). The refractive index of GQDs-PVA compounds reduces and the length of the FP cavity elongates with the increase of RH, which will lead the reflective spectrum shift to length wavelength, and the variation can characterize the change of RH values. The humidity environment is generated by different saturated saline solution, and the RH values are calibrated by a moisture meter. Experiment results reveal that the wavelength shift shows good linearity with the RH changing from 13.47%RH to 81.34%RH, and the sensitivity is 117.25 pm/%RH with the linearity relevancy of 0.9983. In addition, reversibility and repeatability experiments are carried out and the mean square deviation of six sets of data is 1.425×10−3, which indicates good practical development prospects. Taking the practical application into account, the influence of hydrogen and nitrogen in the air on the sensor is studied before humidity experiment, and the experiment results shows that hydrogen and nitrogen in the air have a negligible effect on the humidity sensor proposed in this paper.
•A small and low cost extrinsic Fabry-Perot fiber low-frequency acoustic pressure sensor is proposed.•The EFPAS is fabricated by fusion splicing a single mode fiber with a hollow-core ...fiber.•Experimental results show the sensor has the acoustic pressure sensitivity of 0.427 mV/mPa.
A small and low cost extrinsic Fabry-Perot (FP) fiber low-frequency acoustic pressure sensor (EFPAS) based on polydimethylsiloxane (PDMS) diaphragm is proposed. The EFPAS is fabricated by fusion splicing a single mode fiber (SMF) with a hollow-core fiber (HCF), which embed a PDMS diaphragm by the capillary effect, to form an air micro-cavity. The structural strength of the whole thin diaphragm based sensing probe is improved by the ingenious design, and a high precision optical fiber cutting system can be used to control the length of air micro-cavity. Simulation proves that the PDMS diaphragm with large radius and small thickness will help to improve the sensitivity, but there is a tradeoff between sensitivity and the mechanical strength. Experimental results show that the sensor has the acoustic pressure sensitivity of 0.427 mV/mPa with a high linear pressure response in the range of 5 mPa–720 mPa. A stable signal-to-noise ratio (SNR) about 80 dB with a noise floor at 0 dB can be realized at 30 Hz and a 0.5 Hz resolution can be observed ranging from 10 to 50 Hz of low-frequency acoustic wave (The relative error of measured frequency is lower than 1%). Its high precision of low-frequency acoustic measurement and simple fabrication process make it an attractive tool for acoustic sensing and photo-acoustic spectroscopy.
Plants harbor diverse bacterial communities, which play crucial roles in plant health and growth, in their rhizosphere, phyllosphere and endosphere. Tomato is an important model for studying ...plant-microbe interactions, but comparison of its associated bacterial community is still lacking. In this study, using Illumina sequencing of 16S rRNA amplicons, we characterized and compared the bacterial size and community from rootzone soil as well as the rhizosphere, phyllosphere and endosphere of roots, stems, leaves, fruits and seeds of tomato plants that were grown in greenhouse conditions. Habitat (soil, phyllospheric, and endophytic) structured the community. The bacterial communities from the soil-type samples (rootzone soil and rhizosphere) showed the highest richness and diversity. The lowest bacterial diversity occurred in the phyllospheric samples, while the lowest richness occurred in the endosphere. Among the endophytic samples, both bacterial diversity and richness varied in different tissues, with the highest values in roots. The most abundant phyla in the tomato-associated community was Proteobacteria, with the exception of the seeds and jelly, where both Proteobacteria and Firmicutes were dominant. At the genus level, the sequences of Pseudomonas and Acinetobacter were prevalent in the rhizosphere, and in the phyllosphere, more than 97% of the sequences were assigned to Acinetobacter. For the endophytes, Acinetobacter, Enterobacter, and Pseudomonas were the abundant genera in the roots, stems and leaves. In the fruits, the bacterial endophytes varied in different compartments, with Enterobacter being enriched in the pericarp and seeds, Acinetobacter in the placenta, and Weissella in the jelly. The present data provide a comprehensive description of the tomato-associated bacterial community and will be useful for better understanding plant-microbe interactions and selecting suitable bacterial taxa for tomato production.
Hollow yolk–shell nanoreactors are of great interest in heterogeneous catalysis owing to their improved mass transfer ability and stability. Here, we report a facile and straight route to synthesize ...a highly efficient and recyclable yolk–shell Co@C–N nanoreactor with controllable properties by the direct thermolysis of a hollow Zn/Co-ZIF precursor. Based on systematical optimization of the pyrolysis temperature and the shell-thickness of Zn/Co-ZIFs, we could completely anchor and stabilize uniform Co nanoparticles (NPs) in the hollow yolk, accommodated by the Co-ZIF derived N-doped carbon nanosheets. This nanosheet-assembled yolk was further confined by a permeable and robust N-doped carbon (C–N) shell to protect the Co NPs against leaching and also enabled the reaction to take place in the hollow void. Consequently, the optimal yolk–shell Co@C–N nanoreactor showed a significantly enhanced catalytic activity for the aqueous oxidation of alcohols, yielding >99% conversion under atmospheric air and base-free conditions, which was much higher than that of the solid counterparts derived from pure ZIF-67 and solid core–shell ZIF-67@ZIF-8 precursors (with 14% and 59% conversion under the same reaction condition, respectively). The enhanced catalytic activity should be attributed to the yolk–shell structure that could facilitate the transport of reactant/product and the strong interaction between the Co NPs and N-doped carbon nanosheet to afford positive synergistic effects. Moreover, this catalyst also showed good recyclability, magnetically reusability, and general applicability for a broad substrate scope, further highlighting the structure superiority of our yolk–shell nanoreactor. This strategy might open an avenue to synthesize various hollow yolk–shell nanoreactors with controllable structures and enhanced catalytic performances.
Sepsis-associated encephalopathy (SAE) is a common complication that leads to long-term cognitive impairments and increased mortality in sepsis survivors. The mechanisms underlying this complication ...remain unclear and an effective intervention is lacking. Accumulating evidence suggests the nucleotide-binding domain-like receptor protein3 (NLRP3)/caspase-1 pathway is involved in several neurodegenerative diseases. Thus, we hypothesized that the NLRP3/caspase-1 pathway is involved in NLRP3-mediated pyroptosis, maturation and release of inflammatory cytokines, and cognitive deficits in SAE. We used the NLRP3 inhibitor MCC950 and the caspase-1 inhibitor Ac-YVAD-CMK to study the role of the NLRP3/caspase-1 pathway in pyroptosis and cognitive deficits in a mouse model of SAE. Mice were randomly assigned to one of six groups: sham+saline, sham+MCC950, sham+Ac-YVAD-CMK, cecal ligation and puncture (CLP)+saline, CLP+MCC950, and CLP+Ac-YVAD-CMK. Surviving mice underwent behavioral tests or had hippocampal tissues collected for histochemical analysis and biochemical assays. Our results show that CLP-induced hippocampus-dependent memory deficits are accompanied by increased NLRP3 and caspase-1 positive cells, and augmented protein levels of NLRP3, caspase-1, gasdermin-D, and pro-inflammatory cytokines in the hippocampus. In addition, administration of MCC950 or Ac-YVAD-CMK rescues cognitive deficits and ameliorates increased hippocampal NLRP3-mediated neuronal pyroptosis and pro-inflammatory cytokines. Our results suggest that the NLRP3/caspase-1 pathway-induced pyroptosis mediates cognitive deficits in a mouse model of SAE.
Abstract
Noble metal electrocatalysts (e.g., Pt, Ru, etc.) suffer from sluggish kinetics of water dissociation for the electrochemical reduction of water to molecular hydrogen in alkaline and neutral ...pH environments. Herein, we found that an integration of Ru nanoparticles (NPs) on oxygen-deficient WO
3-x
manifested a 24.0-fold increase in hydrogen evolution reaction (HER) activity compared with commercial Ru/C electrocatalyst in neutral electrolyte. Oxygen-deficient WO
3-x
is shown to possess large capacity for storing protons, which could be transferred to the Ru NPs under cathodic potential. This significantly increases the hydrogen coverage on the surface of Ru NPs in HER and thus changes the rate-determining step of HER on Ru from water dissociation to hydrogen recombination.
A small optical fiber temperature sensor employing the fluorescence lifetime of Mn 4+ doped oxyfluoride germanate phosphor was presented and experimentally demonstrated, which has a fairly good ...temperature measurement precision. The performance of the fluorescent materials for temperature measurement was compared and analyzed. A small temperature sensing probe with a diameter of 1.8 mm was proposed. For the first time, the integrated tee-light-path structure was put forward, the transmission and separation of excitation light and fluorescence in only a single optical path was realized. Experimental results showed that standard deviation errors of 0.45 °C were obtained within the temperature range from 0 °C to 90 °C.
Control of DNA methylation level is critical for gene regulation, and the factors that govern hypomethylation at CpG islands (CGIs) are still being uncovered. Here, we provide evidence that ...G-quadruplex (G4) DNA secondary structures are genomic features that influence methylation at CGIs. We show that the presence of G4 structure is tightly associated with CGI hypomethylation in the human genome. Surprisingly, we find that these G4 sites are enriched for DNA methyltransferase 1 (DNMT1) occupancy, which is consistent with our biophysical observations that DNMT1 exhibits higher binding affinity for G4s as compared to duplex, hemi-methylated, or single-stranded DNA. The biochemical assays also show that the G4 structure itself, rather than sequence, inhibits DNMT1 enzymatic activity. Based on these data, we propose that G4 formation sequesters DNMT1 thereby protecting certain CGIs from methylation and inhibiting local methylation.
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