Functional polymers possess outstanding uniqueness in fabricating intelligent devices such as sensors and actuators, but they are rarely used for converting mechanical energy into electric power. ...Here, a vitrimer based triboelectric nanogenerator (VTENG) is developed by embedding a layer of silver nanowire percolation network in a dynamic disulfide bond‐based vitrimer elastomer. In virtue of covalent dynamic disulfide bonds in the elastomer matrix, a thermal stimulus enables in situ healing if broken, on demand reconfiguration of shape, and assembly of more sophisticated structures of VTENG devices. On rupture or external damage, the structural integrity and conductivity of VTENG are restored under rapid thermal stimulus. The flexible and stretchable VTENG can be scaled up akin to jigsaw puzzles and transformed from 2D to 3D structures. It is demonstrated that this self‐healable and shape‐adaptive VTENG can be utilized for mechanical energy harvesters and self‐powered tactile/pressure sensors with extended lifetime and excellent design flexibility. These results show that the incorporation of organic materials into electronic devices can not only bestow functional properties but also provide new routes for flexible device fabrication.
A flexible and self‐healable triboelectric nanogenerator (TENG) is achieved by combining a vitrimer elastomer and a silver‐nanowire network. By introducing terrace structure, scaling up TENGs can be as easy as playing jigsaw puzzles, which also provides a new fabrication route for flexible devices. The output performance also increases correspondingly when the number of assembly pieces is increased.
Employing a comprehensive structure search and high-throughput first-principles calculation method on 1561 compounds, the present study reveals the phase diagram of Lu–H–N. In detail, the formation ...energy landscape of Lu–H–N is derived and utilized to assess the thermodynamic stability of each compound that is created via element substitution. The result indicates that there is no stable ternary structure in the Lu–H–N chemical system, however, metastable ternary structures, such as Lu
20
H
2
N
17
(
C
2/
m
) and Lu
2
H
2
N (
P
3
¯
m
1
), are observed to have small
E
hull
(< 100 meV/atom). It is also found that the energy convex hull of the Lu–H–N system shifts its shape when applying hydrostatic pressure up to 10 GPa, and the external pressure stabilizes a couple of binary phases such as LuN
9
and Lu
10
H
21
. Additionally, interstitial voids in LuH
2
are observed, which may explain the formation of Lu
10
H
21
and LuH
3–
δ
N
ε
. To provide a basis for comparison, x-ray diffraction patterns and electronic structures of some compounds are also presented.
Intense laser pulses can be used to demagnetize a magnetic material on an extremely short timescale. While this ultrafast demagnetization offers the potential for new magneto-optical devices, it ...poses challenges in capturing coupled spin-electron and spin-lattice dynamics. In this article, we study the photoinduced ultrafast demagnetization of a prototype monolayer ferromagnet Fe
GeTe
and resolve the three-stage demagnetization process characterized by an ultrafast and substantial demagnetization on a timescale of 100 fs, followed by light-induced coherent A
phonon dynamics which is strongly coupled to the spin dynamics in the next 200-800 fs. In the third stage, chiral lattice vibrations driven by nonlinear phonon couplings, both in-plane and out-of-plane are produced, resulting in significant spin precession. Nonadiabatic effects are found to introduce considerable phonon hardening and suppress the spin-lattice couplings during demagnetization. Our results advance our understanding of dynamic charge-spin-lattice couplings in the ultrafast demagnetization and evidence angular momentum transfer between the phonon and spin degrees of freedom.
In contrast to the adult mammalian central nervous system (CNS), the neurons in the peripheral nervous system (PNS) can regenerate their axons. However, the underlying mechanism dictating the ...regeneration program after PNS injuries remains poorly understood. Combining chemical inhibitor screening with gain- and loss-of-function analyses, we identified p90 ribosomal S6 kinase 1 (RSK1) as a crucial regulator of axon regeneration in dorsal root ganglion (DRG) neurons after sciatic nerve injury (SNI). Mechanistically, RSK1 was found to preferentially regulate the synthesis of regeneration-related proteins using ribosomal profiling. Interestingly, RSK1 expression was up-regulated in injured DRG neurons, but not retinal ganglion cells (RGCs). Additionally, RSK1 overexpression enhanced phosphatase and tensin homolog (PTEN) deletion-induced axon regeneration in RGCs in the adult CNS. Our findings reveal a critical mechanism in inducing protein synthesis that promotes axon regeneration and further suggest RSK1 as a possible therapeutic target for neuronal injury repair.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We demonstrate that stronger and more robust nacre-like laminated GO (graphene oxide)/SF (silk fibroin) nanocomposite membranes can be obtained by selectively tailoring the interfacial interactions ...between “bricks”-GO sheets and “mortar”-silk interlayers via controlled water vapor annealing. This facial annealing process relaxes the secondary structure of silk backbones confined between flexible GO sheets. The increased mobility leads to a significant increase in ultimate strength (by up to 41%), Young’s modulus (up to 75%) and toughness (up to 45%). We suggest that local silk recrystallization is initiated in the proximity to GO surface by the hydrophobic surface regions serving as nucleation sites for β-sheet domains formation and followed by SF assembly into nanofibrils. Strong hydrophobic–hydrophobic interactions between GO layers with SF nanofibrils result in enhanced shear strength of layered packing. This work presented here not only gives a better understanding of SF and GO interfacial interactions, but also provides insight on how to enhance the mechanical properties for the nacre-mimic nanocomposites by focusing on adjusting the delicate interactions between heterogeneous “brick” and adaptive “mortar” components with water/temperature annealing routines.
Actin cytoskeleton regulates many essential biological functions, including cellular development, shape, polarity, and motility. The organization of actin cytoskeleton has also been associated with ...numerous physiological and pathological conditions, for instance, the elongation of axonal growth cone during peripheral nerve regeneration. However, the spatio-temporal expression patterns of actin cytoskeleton-related genes and the specific roles of actin cytoskeleton following peripheral nerve injury have not been fully revealed. To address this question, we made rat sciatic nerve crush surgery, collected injured sciatic nerve stumps, analyzed RNA deep sequencing outcomes, and specifically studied two significantly involved canonical pathways that were related with actin, actin cytoskeleton signaling and regulation of actin-based motility by Rho. By using bioinformatic tools and qRT-PCR, We identified and validated differentially expressed genes in these two signaling pathways. Moreover, by applying actin polymerization inhibitor cytochalasin D to sciatic nerve crushed rats, we studied the
effect of cytochalasin D and demonstrated that inhibiting actin polymerization would delay the migration of Schwann cells and hinder the repair and regeneration of injured peripheral nerves. Overall, our data revealed the changes of actin cytoskeleton-related genes following peripheral nerve injury and stated the importance of actin cytoskeleton during peripheral nerve regeneration.
Electronic materials generally exhibit a single isotropic majority carrier type, electrons or holes. Some superlattice
and hexagonal
materials exhibit opposite conduction polarities along in-plane ...and cross-plane directions due to multiple electron and hole bands. Here, we uncover a material genus with this behaviour that originates from the Fermi surface geometry of a single band. NaSn
As
, a layered metal, has such a Fermi surface. It displays in-plane electron and cross-plane hole conduction in thermopower and exactly the opposite polarity in the Hall effect. The small Nernst coefficient and magnetoresistance preclude multi-band transport. We label this direction-dependent carrier polarity in single-band systems 'goniopolarity'. We expect to find goniopolarity and the Fermi surface geometry that produces it in many metals and semiconductors whose electronic structure is at the boundary between two and three dimensions. Goniopolarity may enable future explorations of complex transport phenomena that lead to unprecedented device concepts.
OBJECTIVETo identify suitable reference genes for gene expression studies in rat dorsal root ganglia (DRG) neurons. METHODSThe raw cycle threshold (Ct) values of 12 selected reference genes were ...obtained via quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) in neurons at different developmental stages or under different treatments. Two strategies were employed to screen the most stable reference genes: the genes were ranked according to the coefficient of biological variation and further validated using geNorm and NormFinder programs. The stable and unstable reference genes were subsequently used as internal controls to assess their effects on target gene expression. RESULTSAll reference genes showed varying degrees of fluctuation in Ct values during the growth process of neurons or after different treatments. 18S ribosomal RNA (Rn18s) and β-actin (Actb) exhibited the most significant changes, while ubiquitin C (Ubc), hypoxanthine phosphoribosyl transferase (Hprt), and mitochondrial ribosomal protein L10 (Mrpl10) showed relatively minor changes. The most stable and unstable genes obtained by different evaluation methods varied slightly. Overall, Actb was found to be the most unstable reference gene, while Hprt was the relatively most stable reference gene. The use of unstable reference genes Actb and ankyrin repeat domain 27 (Ankrd27) as internal controls led to high variability within the control group, ultimately affecting the determination of target gene expression. In contrast, the stable reference gene Hprt had small inter-assay variation and high stability. CONCLUSIONSOur observations indicate that Hprt is a proper endogenous reference gene for qRT-PCR analysis in rat DRG neurons and thus provides a critical molecular basis for the genetic characterization in neurological disorders.
PDF
