硅-磷阻燃剂对热塑性聚氨酯弹性体阻燃性能的影响

采用一种含硅阻燃剂——笼形八苯基硅倍半氧烷(OPS)与含磷阻燃剂聚磷酸铵(APP)或二乙基次膦酸铝(ADP)复配制备了阻燃热塑性聚氨酯弹性体(TPU)。结果表明,OPS对TPU的热稳定性有一定的影响,当OPS的质量分数为15%时,能明显改善燃烧过程中的熔滴现象; OPS/APP和OPS/ADP复合阻燃体系,均可以大幅提升TPU的阻燃性能,且APP效果要明显优于ADP; TPU/10%OPS/5%APP体系的综合性能最优,热释放速率峰值从1339 k W/m2降低至489k W/m^2,降幅达到了63.5%,总烟释放量也从3425 m^2/m^2降到1884 m^2/m^2,降幅达到了45.0%;燃烧残余量为18%,锥量测试后的炭层更加致密、坚硬。

含磷纳米复合物/聚氨酯弹性体复合材料的制备与阻燃性能

将自制的DOPO-MMT纳米复合物添加到聚氨酯弹性体中,得到新型聚氨酯弹性体复合材料。并分别与添加了DOPO、蒙脱土(MMT)和DOPO与MMT的物理混合物等的3种体系的阻燃效果作了对比研究,探讨了各体系的阻燃性能及阻燃机理。研究表明,使用纳米复合的DOPO-MMT阻燃剂,阻燃效果要明显优于单独添加DOPO、MMT和物理混合的DOPO和MMT阻燃剂。这是因为DOPO-MMT在聚氨酯中实现了MMT纳米级别的分散,DOPO的气相阻燃和MMT的凝聚相阻燃共同作用抑制了燃烧过程,使得聚氨酯复合材料的UL-94垂直燃烧达到V-2级别,锥形量热测试中有最低的热释放速率和热释放量,材料获得了良好的阻燃效果。

Electrostatic interaction-mediated 1:1 complexes for high-contrast mitochondrial-targeted phosphorescence bioimaging

Organelle-targeted imaging can provide information on cellular functions and intracellular interactions,being significant for disease diagnosis.The use of room-temperature phosphorescence(RTP)in organelle-targeted imaging can fully utilize its unique characteristics of long wavelength and deep penetration.However,this technology has long been plagued by insufficient probe targeting and limited luminous intensity.In this work,we prepared a series of complexes composed of multicationic persulfurated arenes and biomacromolecules via electrostatic interactions in 1:1 stoichiometry for high-contrast mitochondrial-targeted RTP imaging.Such an electrostatic interaction design effectively prevented the self-aggregation of the probes,which is not conducive to mitochondrial targeting.Simultaneously,it suppressed the non-radiative decay to the maximum extent,enabling the probes to exhibit strong RTP signals both in aqueous solution and at the cellular level.Furthermore,the biomacromolecules can serve as carriers for an electrostatic interaction transfer of the persulfurated arenes to mitochondria.This leads to high mitochondrial targeting Pearson's correlation coefficients of the probes and high-contrast RTP imaging effects,as well as the independence of the co-incubated probe concentration.These results provide new insights for the development of targeted imaging technologies.

Facile Blinking Dyes with Spontaneous Enol-Keto Tautomerism for Super-Resolution Imaging of Subcellular Targets

Fluorophores with controlled on–off switching properties and subcellular targeting abilities are essential for modern super-resolution microscopy techniques.However,the effective design strategies of blinking fluorophores are still limited with scarce building blocks(e.g.,rhodamine and cyanine analogues),and sophisticated functionalization is always required for organelle recognition.Therefore,exploring live-cell compatible and organelle-targetable fluorophores with a new blinking mechanism is of broad interest to promote the emerging development of superresolution microscopy.Here,we report a type of live-cell permeable fluorophore with a facile synthesis strategy to facilitate the imaging of lipid droplets and lysosomes using single-molecule localization microscopy.The fluorophores only require a two-step synthetic route.They show signature enol-keto tautomerism by spontaneous proton transfer at the ground state without additional photoactivation,which ensures blinking performance by exciting the minor portion of molecules in keto form.This fluorescence switching mechanism provides a distinct character from that of previously reported live-cell permeable dyes for super-resolution imaging,while the specific organelle binding affinity can be tuned by simply changing the targeting moiety of fluorophores.

Aberration correction for deformable-mirror-based remote focusing enables high-accuracy whole-cell super-resolution imaging

Single-molecule localization microscopy(SMLM)enables three-dimensional(3D)investigation of nanoscale structures in biological samples,offering unique insights into their organization.However,traditional 3D super-resolution microscopy using high numerical aperture(NA)objectives is limited by imaging depth of field(DOF),restricting their practical application to relatively thin biological samples.Here,we developed a unified solution for thick sample super-resolution imaging using a deformable mirror(DM)which served for fast remote focusing,optimized point spread function(PSF)engineering,and accurate aberration correction.By effectively correcting the system aberrations introduced during remote focusing and sample aberrations at different imaging depths,we achieved high-accuracy,large DOF imaging(~8μm)of the whole-cell organelles[i.e.,nuclear pore complex(NPC),microtubules,and mitochondria]with a nearly uniform resolution of approximately 35 nm across the entire cellular volume.

2-[3-氰基呋喃-2(5H)-亚基]丙二腈衍生物的合成及其对Pd^(2+)的识别

通过两步反应合成了一种2-(3-氰基呋喃-2(5H)-亚甲基)丙二腈衍生物TCF-Pyn,该化合物在MeCN/磷酸缓冲容溶液(PBS)(V∶V=2∶8,PBS 2×10^(-2) mol/L,pH=7.4)混合溶液中能高选择性荧光"OFF-ON"识别Pd^(2+),发射波长达到近红外区(653 nm).该探针具有较好的抗干扰能力、较宽的pH适用范围(3~8)和较低的检测限(6.92μmol/L).应用研究表明,TCF-Pyn能检测真实水样中的Pd^(2+),并可对活细胞中的Pd^(2+)进行荧光成像.

Au/La-CeO_(x) catalyst for CO oxidation:Effect of different atmospheres pretreatment on gold state—Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

So far,it is still a controversial issue which status of gold species is a better active site for catalyzing CO oxidation.Herein,the influence of the different atmospheres pretreatment(oxidative and reductive)on gold state of Au/La-CeOx(1 wt%gold loading)catalyst during CO oxidation was studied.The changes of Au species were monitored by combined in situ diffuse reflectance infrared Fourier transform spectroscopy(in situ DRIFTS)and X-ray photoelectron spectroscopy(XPS).For the sample pretreated with oxidative atmosphere,the data show that the initial Au^(3+)is transformed to Au^(δ+)(0<δ<1)during CO oxidation,which is a key step to lead to higher reactivity.For the sample after reductive atmosphere pretreatment,Au^(δ+)is mixed with a small amount of Au^(0)which can be converted to Au^(δ+)with the increase of temperature in reaction.Meanwhile,the sample always maintains high activity during the reaction.Therefore,the Au®+obtained by reductive pretreatment is more active than the Au^(3+)obtained by oxidative treatment in catalyzing CO oxidation.

A bacteria-based system expressing anti-TNF-αnanobody for enhanced cancer immunotherapy

Dear Editor,As a successful drug for inflammatory diseases,the application of TNF-αinhibitor on cancer therapy is limited by repeated administration and off-target effects.1 A body of evidence indicated that the anti-tumor efficacy of TNF-αinhibitor is unsatisfactory,though repeated administration was used to improve its efficacy in tumor-treating fields,it will also lead to severe side effects and high cost.2,3,4 Hence,an efficient and highly targeted TNF-αantibody delivery system is worth developing.

Effective adsorption of quadrivalent cerium by synthesized laurylsulfonate green rust in a central composite design

The layered laurylsulfonate intercalated green rust(lauryl-S GR) was synthesized to evaluate the influence of synthesis parameters and aqueous conditions on the adsorption of CeⅣ.The maximum adsorption capacity of 305.58 mg/g by lauryl-S GR was predictably obtained.The pseudo-first-order kinetic model was appropriate in fitting the whole uptake process in a weak acid environment.Three isotherm models including Langmuir, Freundlich, and Tempkin were all reliable in depicting the isotherm adsorption process.The maximum monolayer adsorption capacity of lauryl-S GR towards CeⅣ was 315.46 mg/g.Ce species including CeO and Ce_(2)O_(3) besides CeO_(2) were matched in the XPS distribution, directly indicating the reduction reaction brought by FeⅡ in the GR occurred to hydrated CeⅣ ions during the adsorption.Nano-sized Ce particles attached to the lauryl-S GRs after the adsorption experiments were observed in the morphological characterization.Flocculated materials were formed on the surface of the lauryl-S GR at a pH of 7, which further reduced the active sites and disrupted the continuous uptake of CeⅣ to the lauryl-S GR.This study expands the application of GRs and supplies an ideal iron-based material for the construction of the affiliated recovery pathway to the traditional separation of Ce.