Exosomes-loaded electroconductive nerve dressing for nerve regeneration and pain relief against diabetic peripheral nerve injury

Over the years,electroconductive hydrogels(ECHs)have been extensively applied for stimulating nerve regeneration and restoring locomotor function after peripheral nerve injury(PNI)with diabetes,given their favorable mechanical and electrical properties identical to endogenous nerve tissue.Nevertheless,PNI causes the loss of locomotor function and inflammatory pain,especially in diabetic patients.It has been established that bone marrow stem cells-derived exosomes(BMSCs-Exos)have analgesic,anti-inflammatory and tissue regeneration properties.Herein,we designed an ECH loaded with BMSCs-Exos(ECH-Exos)electroconductive nerve dressing to treat diabetic PNI to achieve functional recovery and pain relief.Given its potent adhesive and self-healing properties,this laminar dressing is convenient for the treatment of damaged nerve fibers by automatically wrapping around them to form a size-matched tube-like structure,avoiding the cumbersome implantation process.Our in vitro studies showed that ECH-Exos could facilitate the attachment and migration of Schwann cells.Meanwhile,Exos in this system could modulate M2 macrophage polarization via the NF-κB pathway,thereby attenuating inflammatory pain in diabetic PNI.Additionally,ECH-Exos enhanced myelinated axonal regeneration via the MEK/ERK pathway in vitro and in vivo,consequently ameliorating muscle denervation atrophy and further promoting functional restoration.Our findings suggest that the ECH-Exos system has huge prospects for nerve regeneration,functional restoration and pain relief in patients with diabetic PNI.

Self-curling electroconductive nerve dressing for enhancing peripheral nerve regeneration in diabetic rats

Conductive scaffolds have been shown to exert a therapeutic effect on patients suffering from peripheral nerve injuries(PNIs).However,conventional conductive conduits are made of rigid structures and have limited applications for impaired diabetic patients due to their mechanical mismatch with neural tissues and poor plasticity.We propose the development of biocompatible electroconductive hydrogels(ECHs)that are identical to a surgical dressing in this study.Based on excellent adhesive and self-healing properties,the thin film-like dressing can be easily attached to the injured nerve fibers,automatically warps a tubular structure without requiring any invasive techniques.The ECH offers an intimate and stable electrical bridge coupling with the electrogenic nerve tissues.The in vitro experiments indicated that the ECH promoted the migration and adhesion of the Schwann cells.Furthermore,the ECH facilitated axonal regeneration and remyelination in vitro and in vivo through the MEK/ERK pathway,thus preventing muscle denervation atrophy while retaining functional recovery.The results of this study are likely to facilitate the development of non-invasive treatment techniques for PNIs in diabetic patients utilizing electroconductive hydrogels.

Synthesis of Electroconducting Hydroxy-Sodalite/Graphite Composite: Preparation and Characterization

Electroconductive hydroxy-sodalite/graphite composites were synthesized by alkali-activation of kaolinite in the presence of sodium hydroxide as the alkali activator and graphite as a conductive filler. Thermal, morphological and microstructural properties in addition to direct current (D.C.) conductivity of the prepared composites were investigated. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy in the attenuated total reflection mode (FTIR/ATR), X-ray diffraction (XRD), scanning electron microscope/energy dispersive using X-ray analysis (SEM/EDX) and DC conductivity measurements were used to characterize the prepared composites. The effect of the hydroxyl-sodalite-to-graphite and NaOH-to-kaolinite ratios on the electrical conductivity was investigated and evaluated on the generated composite specimens made of Jordanian kaolinite or pure kaolinite. It was demonstrated that increasing the mass ratio of graphite-to-kaolinite in the clay-based composites increased the electrical conductivity of the resultant composites. It was also observed that using 1:1 graphite-to-pure kaolinite mass ratio showed the best electrical conductivity value of 3 × 10-3 s/cm, among the other mass ratios used for pure kaolinite specimens, while using 1:1 mass ratio of graphite-to-Jordanian kaolinite showed a conductivity of 1.6 s/cm.

Investigation of Electrical Stability of Nonwovens with Conductive Circuits Using Printed Conductive Inks

In this work, we study the stability of a class of materials obtained by printing a textile with conductive inks using a method called screen printing. Under the action of a certain external factors, the printed circuit suffers deterioration and the conductivity decreases considerably. In this work, we propose to model the overall damage of the textile sheet in terms of the partial damages of the conductive lines. We also apply this approach to evaluate the damage of a system being made of transmission lines printed into nonwoven substrates using different conductive inks.

Electrically-Conductive Composite Nanomaterial with Multi-Walled Carbon Nanotubes

Specific conductivity of the composite nanomaterial layers with micron and submicron dimensions, consisting of carboxymethyl cellulose (CMC) and multiwalled carbon nanotubes (MWCNT) was investigated. Ultradispersed aqueous suspension was deposited on soft (aluminum foil, plates made from polyester and polyimide, cotton fabric, office paper) and solid (coverslip, silicon wafers with silicon oxide layer) substrates by silk-screen printing. Electrical resistance was measured by four-probe method and by the method of square on surface from which the conductivity and conductivity per square of surface were calculated taking into account layer’s geometric dimensions. Specific conductivity of the layers with thickness range 0.5 - 5 μm was? ~1.2×104÷4×104 S/m, and max conductivity per square was ~ 0.2 S. Investigated nanomaterial is attractive to electronic and biomedical applications.

The Study on the Electrorocket Engine for the Future

A project of electrical rocket engine of the future, which operates on principle of a magnetoplasmadynamic engine, is being considered. New concept of the superconducting magnetic system, stipulating installation of external field winding, in which the current is directed parallel to longitudinal axis of the engine, makes it possible to increase the magnitude of the transversal magnetic field in working chamber, to decrease the rated current and to raise the engine efficiency. On the basis of equations that describe the process of converting electrical energy into mechanical energy, a mathematical model has been composed with whose help the characteristics of magnetoplasma engine having conventional design and the characteristics of the engine being developed in the project have been determined. Conducted research has shown that new design increases engine efficiency from 50% up to 91%. The project also contains a consideration of the new engine design with movable cathode and with cathode having forced cooling which helps to reduce carryover of cathode mass and to increase lifetime by several times. In conclusion, the results of calculations and constructive development of electrorocket engine for flight towards planet Jupiter, which creates tractive force of 250 N at 2500 kW power, are given.

Microlayered Composite Materials on Basis of Copper, Refractory, Rare-Earth Metals, and Carbon for Electrical Contacts and Electrodes

A technology for obtaining microlayered composite materials of Cu-Zr-Y-Mo, Cu-Zr-Y-Cr, Cu-Zr-Y-W and Cu-Zr-Y-C systems by means of high-speed electron-beam evaporation-condensation, structure, electrical, and mechanical properties at ambient and elevated temperatures is developed.

Express Methods for Measurement of Electroconductivity of Semiconductor Layered Crystal

We describe theoretically the grounded method of measuring the conductivity of anisotropic layered semiconductor materials. The suggested method implies the use of a four-probe testing device with a linear arrangement of probes. The final expressions for identifying the electrical conductivity are presented in the form of a series of analytic functions. The suggested method is experimentally verified, and practical recommendations of how to apply it are also provided.

Highly electro-conductive B_(4)C-TiB_(2) composites with threedimensional interconnected intergranular TiB_(2) network

To achieve lightweight B_(4)C-based composite ceramics with high electrical conductivities and hardness,B_(4)C-TiB_(2) ceramics were fabricated by reactive spark plasma sintering(SPS)using B_(4)C,TiC,and amorphous B as raw materials.During the sintering process,fine B_(4)C-TiB_(2) composite particles are firstly in situ synthesized by the reaction between TiC and B.Then,large raw B_(4)C particles tend to grow at the cost of small B_(4)C particles.Finally,small TiB_(2) grains surround large B_(4)C grains to create a three-dimensional interconnected intergranular TiB_(2) network,which is beneficial for an electro-conductive network and greatly improves the conductivity of the ceramics.The effect of the B_(4)C particle size on the mechanical and electrical properties of the ceramics was investigated.When the particle size of initial B_(4)C powders is 10.29µm,the obtained B_(4)C-15 vol%TiB_(2) composite ceramics exhibit an electrical conductivity as high as 2.79×10^(4) S/m and a density as low as 2.782 g/cm^(3),together with excellent mechanical properties including flexural strength,Vickers hardness(HV),and fracture toughness(KIC)of 676 MPa,28.89 GPa,and 5.28 MPa·m^(1/2),respectively.

Preparation and lithium storage performances of g-C_(3)N_(4)/Si nanocomposites as anode materials for lithium-ion battery

As the anode material of lithium-ion battery,silicon-based materials have a high theoretical capacity,but their volume changes greatly in the charging and discharging process.To ameliorate the volume expansion issue of silicobased anode materials,g-C_(3)N_(4)/Si nanocomposites are prepared by using the magnesium thermal reduction technique.It is well known that g-C_(3)N_(4)/Si nanocomposites can not only improve the electronic transmission ability,but also ameliorate the physical properties of the material for adapting the stress and strain caused by the volume expansion of silicon in the lithiation and delithiation process.When g-C_(3)N_(4)/Si electrode is evaluated,the initial discharge capacity of g-C_(3)N_(4)/Si nanocomposites is as high as 1033.3 mAh/g at 0.1 A/g,and its reversible capacity is maintained at 548 mAh/g after 400 cycles.Meanwhile,the improved rate capability is achieved with a relatively high reversible specific capacity of 218 mAh/g at 2.0 A/g.The superior lithium storage performances benefit from the unique g-C_(3)N_(4)/Si nanostructure,which improves electroconductivity,reduces volume expansion,and accelerates lithiumion transmission compared to pure silicon.

Influence of oxygen non-stoichiometry on physical properties of NdSr_2Mn_2O_(7±δ)

Nd Sr2Mn2O7＋δ compounds were synthesized by ceramic method under three different cooling conditions. The Nd Sr2Mn2O7＋δ samples were characterized by powder X-ray diffraction（XRD）. Oxygen non-stoichiometry data for the studied powders were determined by using gravimetric and X-ray photoelectron spectroscopy（XPS） methods. The correlation of cooling method and oxygen as non-stoichiometry was established. The electroconductivity in samples was studied by using four-point probe method, and the strong correlation with non-stoichiometry was found out. Magnetization measurements were carried out. It was found that the magnetic and transport properties of the samples were also influenced by oxygen non-stoichiometry. The evolution of the magnetic properties could be explained by the formation of magnetic clusters in the vicinity of oxygen vacancies（OV） and strong competition between the superexchange and double exchange interactions.