蓝光导致皮肤色素沉着的发生机制研究

蓝光是一种波长为400~500 nm的可见光,其对人体主要危害有损伤眼周及眼部结构、加速皮肤老化、抑制褪黑素分泌、造成皮肤色素沉着等。当前,关于蓝光导致皮肤色素沉着的研究较少,文章首次系统地整理了蓝光导致皮肤色素沉着的发生机制,其主要包含蓝光对视蛋白3、α-MSH-MC1R通路、黑皮素受体、细胞因子等产生影响最后导致黑素生成增加,引发皮肤色素沉着。为后续相关研究提供了思路与理论基础。

Age and fluid source constraints of the Haoyaoerhudong orogenic gold deposit,North China:Evidence from geochronology and noble gas isotopes

The Haoyaoerhudong gold deposit,located in the northwestern part of the North China craton(NCC),has produced over 120 metric tonnes(t)of gold since 2007.It has a total reserve of>240 t at average gold grade of 0.62 g/t,making it one of the largest open pit gold mines in China.The steeply dipping,large-tonnage,low-grade,vein-or veinlet-type gold orebodies are hosted in strongly-deformed Mesoproterozoic carbonaceous schist of the Bayan Obo Group.The laminated/boudinaged veins/veinlets in the sinistral ductile-brittle shear zones are dominated by quartz,biotite,gold-bearing löllingite,pyr-rhotite,(arseno)pyrite,with minor native gold,titanite and xenotime.In this paper,we present new in situ U-Pb geochronological data on magmatic zircon from the preore dikes,on metamorphic and hydrothermal xenotime,and on hydrothermal titanite from the hydrothermally altered carbonaceous schist and auriferous quartzsulfides veins/veinlets,as well as He-Ar isotopic analysis on gold-bearing(arseno)pyrite in the syn-ore stage.The metamorphic xenotime U-Pb age of 426±6.0 Ma(2σ)records a regional metamorphic event,possibly related to the accretion of the Bainaimiao arc onto the NCC.Two pre-ore andesitic dikes yielded similar emplacement ages at~278 Ma constrained by laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)U-Pb zircon data.Hydrothermal xenotime grains from the altered carbonaceous schist and auriferous quartz-sulfides veins yielded U-Pb ages of 256.0±4.1 Ma(2σ)and 254.4±2.1 Ma(2σ),respectively,overlapping with that of the hydrothermal titanite at 255.4±0.8 Ma(2σ)from the laminated quartz-sulfides veinlets.This indicates that the gold mineralization occurred at ca.255 Ma.The~255 Ma gold mineralization age is much younger than the previously reported Early-Middle Permian regional magmatic activity(ca.291 Ma to 268 Ma),and may be associated with the regional sinistral strike-slip event in the late orogenic cycle related to the collision between the Siberian craton and the NCC.The 3He/4He(R/Ra)and 40Ar/36Ar values of the gold-bearing(arseno)pyrite are 0.04 to 0.09(average=0.07)and 375.8 to 2023(average=1045),which reveal the ore-forming fluids dominantly originated from the crustal rocks,with limited involve-ment from the mantle.Collectively,our new geochronological data,noble gas isotopic analyses,and geo-logical evidence support a typical orogenic gold deposit model at Haoyaoerhudong.

Large-scale blow spinning of heat-resistant nanofibrous air filters

Particulate matter(PM)pollution has become a serious problem worldwide and various kinds of nanofibrous filters aiming to solve the problem have been developed.It is urgent to remove PM from high-temperature pollution sources,such as industrial emissions,coal furnaces,and automobile exhaust gases.However,filtration at pollution sources remains challenging because most existing air filters are not resistant to high temperature.Herein,heat-resistant polyimide(PI)nanofibrous air filters are fabricated via a simple and scalable solution blow-spinning method.These air filters show excellent thermal stability at high temperature up to 420℃.They exhibit a filtration efficiency as high as 99.73%at ambient temperature and over 97%at 300℃.In addition,a field test shows that the filters remove>97%of PM from the car exhaust fumes.Hence,the blow-spun PI nanofibrous membranes combined with the facile preparation strategy have great potential in high temperature air filtration fields and other similar applications such as water purification and protein separation.

A large-area AgNW-modified textile with high-performance electromagnetic interference shielding

Manufacturing a flexible,light,large-area,and high-efficiency electromagnetic shielding materials in a straightforward and cost-effective manner presently remains a significant challenge.In this work,we propose a conductive network design and verify its electromagnetic interference(EMI)shielding effectiveness(SE)by simulation.Using the structure and parameters obtained by simulation,we prepare a flexible EMI shielding material using silver nanowires(AgNWs)/polyvinyl butyral(PVB)ethanol solution and textile substructure via a facile immersing method.In the frequency range of 5-18 GHz,the AgNWs/PVB textile with 1.4 mm thickness achieves an EMI SE of 59 dB,which exceeds the requirements for commercial applications.Due to the low density of 56 mg/cm^(3),specific shielding effectiveness(SSE)of this material reaches 1053 dB m^(3)/g.It is found that the AgNWs/PVB textile is more resistant to washing with water and oxidation than AgNWs textile without a PVB protector.As a result,the conductivity of AgNWs/PVB textile exhibits no change after washing with water and varies slightly after being kept in hot air.We find that a signal monitor is unable to detect a signal emitted by a mobile phone from a jacket lined with AgNWs/PVB textile.AgNWs/PVB textile with these properties can be mass-produced as high-efficiency EMI shielding material for commercial applications.

An ultralight,flexible,and biocompatible all-fiber motion sensor for artificial intelligence wearable electronics

New-generation human body motion sensors for wearable electronics and intelligent medicine are required to comply with stringent requirements in terms of ultralight weight,flexibility,stability,biocompatibility,and extreme precision.However,conventional sensors are hard to fulfill all these criteria due to their rigid structure,high-density sensing materials used as the constituents,as well as hermetical and compact assembly strategy.Here,we report an ultralight sensing material based on radial anisotropic porous silver fiber(RAPSF),which has been manufactured by phase separation and temperature-controlled grain growth strategy on a modified blow-spinning system.The resistance of RAPSF could be dynamically adjusted depending on the deflected shape.Furthermore,an all-fiber motion sensor(AFMS)with an ultra-low density of 68.70 mg cm^(−3) and an overall weigh of 7.95 mg was fabricated via layer-by-layer assembly.The sensor exhibited outstanding flexibility,breathability,biocompatibility,and remarkable body motion recognition ability.Moreover,the AFMS was shown to have great potential as an artificial intelligence throat sensor for throat state identification at the accuracy above 85%,allowing one to spot the early onset of the viral throat illness.

Low-Carbon and Nanosheathed ZnCo_(2)O_(4) Spheroids with Porous Architecture for Boosted Lithium Storage Properties

Multielectronic reaction electrode materials for high energy density lithium-ion batteries(LIBs)are severely hindered by their inherent sluggish kinetics and large volume variations,leading to rapid capacity fade.Here,a simple method is developed to construct low-carbon and nanosheathed ZnCo_(2)O_(4) porous spheroids(ZCO@C-5).In this micro/nanostructure,an ultrathin amorphous carbon layer(∼2 nm in thickness)is distributed all over the primary nanosized ZCO particles(∼20 nm in diameter),which fnally self-assembles into porous core(ZCO)-shell(carbon)micron spheroids.Te nanoencapsulation and macro/mesoporous architecture can not only provide facile electrolyte penetration and rapid ion/electron transfer but also better alleviate volumetric expansion efect to avoid pulverization of ZCO@C-5 spheroids during repeat charge/discharge processes.As expected,the three-dimensional porous ZCO@C-5 composites exhibit high reversible capacity of 1240 mAh g^(−1) cycle at 500 mA g^(−1),as well as excellent long-term cycling stability and rate capability.Te low-carbon and nanoencapsulation strategy in this study is simple and efective,exhibiting great potential for high-performance LIBs.

Ten-Hour Stable Noninvasive Brain-Computer Interface Realized by Semidry Hydrogel-Based Electrodes

Noninvasive brain computer interface(BCI)has been extensively studied from many aspects in the past decade.In order to broaden the practical applications of BCI technique,it is essential to develop electrodes for electroencephalogram(EEG)collection with advanced characteristics such as high conductivity,long term efectiveness,and biocompatibility.In this study,we devcloped a silver-nanowire/PVA hydrogc/mclamine sponge(AgPHMS)semidry EEG electrode for long lasting monitoring of EEG signal.Benefiting from the water storage capacity of PVA hydrogel,the clectrolyte solution can be continuously released to the scalpelctrode interface during used.The electrolyte solution can infiltrate the stratum corneum and reduce the scalp-electrode impedance to 10k0-15k0.The flexible structure enabls the electrode with mechanical stability,increases the wearing comfort,and reduces the scalp-electrode gap to reduce contact impedance.As a result,a long-term BCI application based on measurements of motion-onset visual evoked potentials(mVEPs)shows that the 3-hour BCI accuracy of the new electrode(77%to 100%)is approximately the same as that of conventional eletrodes supported by a conductive gel during the first hour.Furthermore,the BCI system based on the new electrode can retain low contact impedance for 10 hours on scalp,which greatly improved the ability of BCI technique.