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The contribution of fiber alignment of scaffold on cellular mechanisms was evaluated by a comparative study of two different cells sourced from cornea. Electrospun scaffolds with similar composition and comparable fiber size were fabricated into randomly oriented and aligned scaffolds, which bear paralleled degradation of gelatin. Tensile test of wet scaffolds indicated that fiber alignment could influence its mechanical properties. Due to the unidirectional fiber orientation, aligned scaffold exhibited higher tensile modulus, higher break strength, and lower elongation at break than randomly oriented scaffold. The effect of fiber alignment on cells behavior was evaluated by cell morphology, specific protein expression, adhesion, and proliferation. Different corneal cells responded uniquely to fiber alignment of scaffold, keratocytes interacting more favorably on alignment scaffold and corneal epithelial cells more favorably on randomly oriented scaffold. These results confirmed that fiber alignment of scaffold would be benefit for cell proliferation if its contact guidance coincided with the cell shape and cytoskeletal tension. This finding is important to envisage an advanced composite scaffold that incorporates randomly oriented and aligned fibers for the growth and control of different cell types required for the successful development of corneal grafts by tissue engineering.

and high density. [4][5][6][7] Moreover, memristors with analog switching behaviors can faithfully resemble biological computational elements in both structure and switching dynamics. With the intrinsic biomimetic features, memristors could act as the basic computational element in artificial neural networks and have been demonstrated with the capability of solving cognitive computing tasks with spatiotemporal complexity without complex peripheral circuits. [7] Among various material systems, 2D materials recently demonstrated memristive switching behaviors that possess biologically comparable energy consumption compared with the traditional memristors based on oxide materials. [8][9][10][11] Thanks to their atomically thin layers and planar configurations, 2D material based memristors have provided an intriguing window into the motions of ions and opportunities to achieve outstanding electrical performances. [12][13][14] It has been reported that vertical synapses built in 2D MoS 2 push the switching threshold voltages to an extremely low value of 0.1 V. [14] More recently, multiterminal memtransistor consisting of hybrid memristor and transistor were fabricated using 2D materials to realize gate-tunable heterosynaptic functionality, which could not be achieved with transitional materials. [4,15,16] In addition, the rapid development of chemical vapor deposition (CVD) technology enables wafer scale production of 2D material, paving the way for large scale integration of 2D devices. Therefore, dimensionality reduction from 3D to 2D provides an innovative way for further advancing memristor devices in both scalability and electrical performance.Despite enormous efforts have been devoted in investigating 2D material based memristors, progresses are only made on emulating various synaptic functions. Neuromorphic networks comprise layers of artificial neurons that receive, process and transmit signals, and synapses that connect the neurons and evolve to alter the connection patterns during learning. [17,18] Although artificial neurons based on traditional oxide and phase change materials have been implemented, 2D materials have their distinct advantages. [19,20] For instance, the physical properties of 2D materials can easily be modulated by multi factors, such as doping and interface engineering, 2D material based memristors have exhibited superior performance as artificial synapses for neuromorphic computing. However, 2D artificial neurons as have note been exploited as an indispensable computational element owing to the rich dynamics of neurons, which impede the construction of a 2D neuromorphic network. A methodology is developed by introducing ionic migration dynamics and electrochemical reaction into monolayer MoS 2 single crystal and a 2D artificial neuron is realized. The sophisticated electrophysiology process of leaky integrate-and-fire (LIF) is emulated by the injection and extraction of Ag + ions under an e-field in a monolayer MoS 2 device with fine-tuned channel length. Moreover, the fire frequency and ...

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We extract 18 candidate short gamma-ray bursts (SGRBs) with precursors from 660 SGRBs observed by the Fermi and Swift satellites, and carry out a comprehensive analysis of their temporal and spectral features. We obtain the following results: (1) for a large fraction of candidates, the main burst durations are longer than their precursor durations, comparable to their quiescent times from the end of precursors to the beginning of their main bursts. (2) The average flux of precursors tends to increase as their main bursts brighten. (3) As seen from the distributions of hardness ratio and spectral fitting, the precursors are slightly spectrally softer with respect to the main bursts. Moreover, a significant portion of precursors and all main bursts favor a non-thermal spectrum. (4) The precursors might be a probe of the progenitor properties of SGRBs such as the magnetic field strength and the crustal equation of state if they arise from some processes before mergers of binary compact objects rather than post-merger processes.

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