As an important precursor and derivate of graphene, graphene oxide (GO) has received wide attention in recent years. However, the synthesis of GO in an economical and efficient way remains a great challenge. Here we reported an improved NaNO3-free Hummers method by partly replacing KMnO4 with K2FeO4 and controlling the amount of concentrated sulfuric acid. As compared to the existing NaNO3-free Hummers methods, this improved routine greatly reduces the reactant consumption while keeps a high yield. The obtained GO was characterized by various techniques, and its derived graphene aerogel was demonstrated as high-performance supercapacitor electrodes. This improved synthesis shows good prospects for scalable production and applications of GO and its derivatives.
SUMMARY
Proper bipolar attachment of sister kinetochores to the mitotic spindle is critical for accurate chromosome segregation in mitosis. Here we show an essential role of the formin mDia3 in achieving metaphase chromosome alignment. This function is independent of mDia3 actin nucleation activity, but is attributable to EB1-binding by mDia3. Furthermore, the microtubule binding FH2 domain of mDia3 is phosphorylated by Aurora B kinase in vitro, and cells expressing the nonphosphorylatable mDia3 mutant cannot position chromosomes at the metaphase plate. Purified recombinant mDia3 phosphorylated by Aurora B exhibits reduced ability to bind microtubules and stabilize microtubules against cold-induced disassembly in vitro. Cells expressing the phosphomimetic mDia3 mutant do not form stable kinetochore microtubule fibers; despite they are able to congress chromosomes to the metaphase plate. These findings reveal a key role for mDia3 and its regulation by Aurora B phosphorylation in achieving proper stable kinetochore microtubule attachment.
Hydrogel-based sensors have attracted significant attention owing to their promising applications in artificial intelligence. However, developing robust hydrogel conductors with customizable functionality and excellent sensor properties is challenging. In this...
Development
of intelligent adaptable materials with unprecedented
sensitivity that can mimic the tactile sensing functions of natural
skin is a major driving force in the realization of artificial intelligence.
Herein, we judiciously designed and synthesized a series of lauryl
acrylate-based polymeric organogels with high transparency, mechanical
adaptability, self-healing properties, and adhesive capability. Moreover,
a robust capacitive sensor with high sensitivity (0.293 kPa–1) was developed by sandwiching the prepared soft, adaptable organogels
between two tough conductive hydrogels and then used to monitor various
human motions such as finger stretching, wrist bending, and throat
movement during chewing. Interestingly, the resulting capacitive sensor
could also function as prosthetic skin on a pneumatic soft artificial
hand, enabling intelligent haptic perception. The research disclosed
herein is expected to provide insights into the rational design of
artificial human-like skins with unprecedented functionalities.
Thermally
conductive, robust, but self-healable polymer/carbon
nanocomposites are the research focus in functional materials. However,
the trade-off between molecular interaction and cross-linking makes
it difficult to simultaneously achieve excellent self-healing, high
strength, and thermal conduction. Herein, we fabricated boroxine poly(dimethylsiloxane)
2-ureido-4[1H]-pyrimidinone selectively cross-linked
by molecular boron ester bonds and hydrogen bonds. By optimizing the
reversible interaction, a maximum strength of 7.33 MPa and a high
self-healing efficiency of 97.69 ± 0.33% were achieved at a boroxine-to-2-ureido-4[1H]-pyrimidinone molar ratio of 1:3 (BE-PDMS1:3-UPy). Highly robust composites of BE-PDMS1:3-UPy were
obtained using a UPy-modified graphene aerogel. A transected sample
recovered its mechanical properties (78.83 ± 2.40%) and thermal
conductivity (98.27 ± 0.13%) after self-healing at 40 °C
for 6 h. The outstanding reversible association/disassociation of
hydrogen bonds at the polymer–graphene interface makes the
composites to be used as structure–function integrated materials
in interfacial thermal conductors.
As one of the simple and efficient routes to access two-dimensional materials, liquid exfoliation has received considerable interest in recent years. Here, we reported on high-efficient liquid exfoliation of hexagonal boron nitride nanosheets (BNNSs) using monoethanolamine (MEA) aqueous solution. The resulting BNNSs were evaluated in terms of the yield and structure characterizations. The results show that the MEA solution can exfoliate BNNSs more efficiently than the currently known solvents and a high yield up to 42% is obtained by ultrasonic exfoliation in MEA-30 wt% H2O solution. Finally, the BNNS-filled epoxy resin with enhanced performance was demonstrated.Electronic supplementary materialThe online version of this article (10.1186/s11671-017-2366-4) contains supplementary material, which is available to authorized users.
The first flexible organic-heterojunction neuromorphic transistor (OHNT) that senses broadband light, including near-ultraviolet (NUV), visible (vis), and near-infrared (NIR), and processes multiplexed-neurotransmission signals is demonstrated. For UV perception, electrical energy consumption down to 536 aJ per synaptic event is demonstrated, at least one order of magnitude lower than current UV-sensitive synaptic devices. For NIR-and vis-perception, switchable plasticity by alternating light sources is yielded for recognition and memory. The device emulates multiplexed neurochemical transition of different neurotransmitters such as dopamine and noradrenaline to form short-term and long-term responses. These facilitate the first realization of human-integrated motion state monitoring and processing using a synaptic hardware, which is then used for real-time heart monitoring of human movement. Motion state analysis with the 96% accuracy is then achieved by artificial neural network. This work provides important support to future biomedical electronics and neural prostheses.
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