3D Printed Integrated Gradient-Conductive MXene/CNT/Polyimide Aerogel Frames for Electromagnetic Interference Shielding with Ultra-Low Reflection

Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/carbon nanotube/polyimide(gradient-conductive MXene/CNT/PI,GCMCP)aerogel frame with hierarchical porous structure and gradient-conductivity has been constructed to achieve EMI shielding with ultra-low reflection.The gradient-conductive structures are obtained by continuous 3D printing of MXene/CNT/poly(amic acid)inks with different CNT contents,where the slightly conductive top layer serves as EM absorption layer and the highly conductive bottom layer as reflection layer.In addition,the hierarchical porous structure could extend the EM dissipation path and dissipate EM by multiple reflections.Consequently,the GCMCP aerogel frames exhibit an excellent average EMI shielding efficiency(68.2 dB)and low reflection(R=0.23).Furthermore,the GCMCP aerogel frames with miniaturized and programmable structures can be used as EMI shielding gaskets and effectively block wireless power transmission,which shows a prosperous application prospect in defense industry and aerospace.

Neuroprotective effects of Ginkgo biloba dropping pills in Parkinson's disease

Parkinson's disease(PD) is the second most common neurodegenerative disease in the world;however,it lacks effective and safe treatments. Ginkgo biloba dropping pill(GBDP), a unique Chinese G. biloba leaf extract preparation, exhibits antioxidant and neuroprotective effects and has a potential as an alternative therapy for PD. Thus, the aims of this study were to evaluate the effects of GBDP in in vitro and in vivo PD models and to compare the chemical constituents and pharmacological activities of GBDP and the G. biloba extract EGb 761. Using liquid chromatography tandem-mass spectrometry, 46 GBDP constituents were identified. Principal component analysis identified differences in the chemical profiles of GBDP and EGb 761. A quantitative analysis of 12 constituents showed that GBDP had higher levels of several flavonoids and terpene trilactones than EGb 761, whereas EGb 761 had higher levels of organic acids.Moreover, we found that GBDP prevented 6-hydroxydopamine-induced dopaminergic neuron loss in zebrafish and improved cognitive impairment and neuronal damage in methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD mice. Although similar effects were observed after EGb 761 treatment,the neuroprotective effects were greater after GBDP treatment on several endpoints. In addition, in vitro results suggested that the Akt/GSK3β pathway may be involved in the neuroprotective effects of GBDP.These findings demonstrated that GBDP have potential neuroprotective effects in the treatment of PD.

3D Printed Polyimide/Silica Composite Aerogels for Customizable Thermal Insulation from-50℃ to 1300℃

Aerogels are widely used as thermal insulation materials because of their high porosity and low bulk density.However,the insulation performance of aerogels is limited to a narrow temperature range.Besides,the preparation of aerogel materials with precisely controlled and complex architectures is still challenging.Here,we report 3D printed polyimide/silica aerogel particle(PI/SAP)composite aerogels for thermal insulation in a wide range of temperature with customized applications.The printability and shape fidelity of 3D printed composite aerogels is improved by adding hydrophilic SAP as a rheology modifier.The resulting PI/SAP composite aerogel exhibits excellent flame-retardant properties and thermal insulation from-50℃ to 1300℃.Moreover,the PI/SAP composite aerogel with customized shape can be applied for battery insulation at subzero temperatures,promising to be used as customizable and stable insulating materials in a variety of complex and extreme applications.

Fluorine-containing polyimide nanofiber membranes for durable and anti-aging daytime radiative cooling

Personal daytime radiative cooling(PDRC)materials have high sunlight reflection and high selective emis-sivity to outer space in the main atmospheric window,demonstrating huge potential in energy-saving for sustainable development.Recently,polymer-based membranes for radiative cooling have been widely re-ported,due to their easy processing,low cost,and unique optical performance.However,the desired high sunlight reflectance of PDRC materials is easily dampened by environmental aging,high temperature,and ultraviolet(UV)irradiation,resulting in reduced cooling performance for most polymers,adverse to large-scale practical applications.In this work,we demonstrate a novel polyimide nanofiber(PINF)membrane with a fluorine-containing structure via typical electrospinning technology.The resultant PINF membrane exhibits high sunlight reflectance,UV resistance,and excellent thermal stability,rendering anti-aging day-time radiative cooling.The sunlight reflectance of PINF membranes could maintain constant in the aging test for continuous 720 h under outdoor solar irradiation,exhibiting durable and long-term personal day-time radiative cooling performance.

Enantioseletive bioaccumulation of tebuconazole in earthworm Eisenia fetida

Methods of extraction and determination of tebuconazole enantiomers in earthworm （Eisenia fetida） were developed by capillary electrophoresis （CE） and high performance liquid chromatography （HPLC）. Both CE and HPLC have excellent resolution and recovery. The linearity ranges were 2.9-102.4 mg/kg and 3.0-99.6 mg/kg for （＋）-R-tebuconazole and （-）-S-tebuconazole respectively in CE, and from 0.56 to 1000 mg/kg for both enantiomers in HPLC. Enantioselective bioaccumulation in earthworms from soft was investigated under laboratory condition at concentrations of 10 and 50 mg/kg dw in soil. The uptake kinetics of （＋）-R-tebuconazole fitted the first- order kinetics well with r2 0.97 and 0.94 under 10 and 50 mg/kg dw exposure condition, respectively, while （-）-S-tebuconazole with r2 0.75 and 0.22 did not show the same. Bioaccumulation of tebuconazole in earthworm tissues was enantioselective with a preferential accumulation of （＋）-R-tebuconazole. The （＋）-R-tebuconazole might also have biomagnifying effect potential in earthworm food chain with biota-sediment accumulation factor （BSAF） of 1.64 kg OC/kg lip in 10 mg/kg dw exposure group and 2.61 kg OC/kg lip in 50 mg/kg dw exposure group from soil to earthworm after 36 days. Although （-）-S-tebuconazole shares the same physicochemical properties with （＋）-R-tebuconazole, it did not biomaguify. BSAFs of （-）-S-tebuconazole were 0.50 kg OC/kg lip （10 mg/kg dw tebuconazole exposure） and 0.28 kg OC/kg lip （50 mg/kg dw tebuconazole exposure） after 36 days, which was possibly owing to biotransformation or metabolism in earthworm tissues.