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Peripheral nerve defect are common clinical problem caused by trauma or other diseases, often leading to the loss of sensory and motor function in patients. Autologous nerve transplantation has been the gold standard for repairing peripheral nerve defects, but its clinical application is limited due to insufficient donor tissue. In recent years, the application of tissue engineering methods to synthesize nerve conduits for treating peripheral nerve defect has become a current research focus. This study introduces a novel approach for treating peripheral nerve defects using a tissue‐engineered PLCL/SF/NGF@TA‐PPy‐RGD conduit. The conduit was fabricated by combining electrospun PLCL/SF with an NGF‐loaded conductive TA‐PPy‐RGD gel. The gel, synthesized from RGD‐modified tannic acid (TA) and polypyrrole (PPy), provides growth anchor points for nerve cells. In vitro results showed that this hybrid conduit could enhance PC12 cell proliferation, migration, and reduce apoptosis under oxidative stress. Furthermore, the conduit activated the PI3K/AKT signalling pathway in PC12 cells. In a rat model of sciatic nerve defect, the PLCL/SF/NGF@TA‐PPy‐RGD conduit significantly improved motor function, gastrocnemius muscle function, and myelin sheath axon thickness, comparable to autologous nerve transplantation. It also promoted angiogenesis around the nerve defect. This study suggests that PLCL/SF/NGF@TA‐PPy‐RGD conduits provide a conducive environment for nerve regeneration, offering a new strategy for peripheral nerve defect treatment, this study provided theoretical basis and new strategies for the research and treatment of peripheral nerve defect. [ABSTRACT FROM AUTHOR]

The polyvinylidene fluoride/polysulfone-amide (PVDF/PSA) composite nanofiber mats were prepared via electrospinning method and characterized systematically by means of scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-Ray diffraction (XRD) and Thermogravimetric analyzer (TGA). In this study, five PVDF/PSA composite spinning solutions with the setting of different mass ratio were mixed by using mechanical agitation method. The mechanical property, wettability and the air permeability of the PVDF/PSA composite nanofiber mats were also measured and discussed. The results show that the addition of PSA has tuned the composite nanofiber mats from hydrophobic to hydrophilic. It is also found that the mechanical property, thermal stability could be improved with the increasing percentage of PVDF component. The PVDF/PSA composite nanofiber mats with the mass ratio of 5/5 gives the best air permeability. In this work, the newly developed composite nanofiber mats have the potential applications in the development of filtration membranes, protective materials, lithium battery diaphragms, etc. [ABSTRACT FROM AUTHOR]

In this study, a novel electrospinning method and the related spinning device were developed to fabricate a new type of polysulfone amide yarn assembled with nanoscale fiber. The electrospun nanofibers extruded and stretched under the electric field force were assembled and twisted with a rotating receiver, so the freshly prepared nanofibers could be bundled into yarns continuously. The effects of solid concentration and the rotating speed of the collector on the yarn structures and properties were investigated systematically. The three-dimensional electric field was modeled and calculated theoretically to simulate the electric field distribution of the electrospinning system. The experimental results showed that the morphology, mechanical strength, and thermal and wicking properties were obviously affected by solid concentration and the rotating speed of the collector. It was found that the nanoyarn could achieve a better performance in morphology, strength, heat resistance, moisture absorption at 12 wt% and 40 r/min collector rotating speed. Therefore, the proposed advanced electrospinning technique in this paper could be used to produce multi-functional nanoyarns, which may be useful for the application of nanoyarns in various industrial fields. [ABSTRACT FROM AUTHOR]

Typical algorithms of multidimensional space-vector pulsewidth modulation (SVPWM) divide (n –1) dimensional space into (n–1)/2 subplanes with decoupling matrix or symmetrical component approach. However, the determination of effective sectors and appropriate space voltage vectors takes a heavy computing burden. Taking the five-phase inverter as example, the relationship between the operation time of branch switches and the dwell times of active space vectors in the SVPWM method is analyzed in this paper. Then, the branch space voltage vector (BSVV) corresponding to the individual active branch voltage is defined and the synthesis of other active space voltage vectors using BSVVs is given. Furthermore, only the BSVVs are chosen as the base vectors to synthesize the reference voltage vector, and a novel SVPWM algorithm is present. The operation time of branch switch is deduced, and the equivalence of the normalized load-phase voltages and operation times of branch switches is emphasized and used to analyze the simulation results. The zero-sequence voltage vector is also included in the algorithm as a parameter and its effects on the dwell time of the BSVVs, the modulation index and the common-mode voltage are explicated. Finally, the extension to an n-phase system is discussed. The algorithm eliminates the selection of sectors and proper active space vectors, and can effectively control the dwell time of switches of multiphase inverter. Experimental results proved the feasibility and effectiveness of the algorithm. [ABSTRACT FROM AUTHOR]