Robust and Tunable Ferroelectricity in Ba/Co Codoped (K_(0.5)Na_(0.5))NbO_(3) Ceramics

The 0.98(K_(0.5)Na_(0.5))NbO_(3)-0.02Ba(Nb_(0.5)Co_(0.5))O_(3-δ) ceramics with doped Ba^(2+) and Co^(2+) ions are fabricated,and the impacts of the thermal process are studied.Compared with the rapidly cooled (RC) sample,the slowly cooled (SC) sample possesses superior dielectric and ferroelectric properties,and an 11 K higher ferroelectricparaelectric phase transition temperature,which can be attributed to the structural characteristics such as the grain size and the degree of anisotropy.Heat treatment can reversibly modulate the content of the oxygen vacancies,and in turn the ferroelectric hysteresis loops of the samples.Finally,robust and tunable ferroelectric property is achieved in SC samples with good structural integrity.

Synergically enhanced piezocatalysis performance of eco-friendly(K_(0.52)Na_(0.48))NbO_(3) through ferroelectric polarization and defects

Piezocatalysis has attracted unprecedented research interest as a newly emerging catalysis technology.However,the inherent insulating property of ferroelectric materials ultimately leads to the poor vibration-electricity conversion ability.Herein,this work reports the(K_(0.52)Na_(0.48))NbO_(3) ferroelectric ceramics(KNNFCx),for which the FeCo modification strategy is proposed.The substitution of the moderate amount of FeCo(x=0.015)at Nb site not only optimizes ferroelectricity but also produces beneficial defects,notably increasing Rhodamine B water purification efficiency to 95%.The pinning effect of monovalent oxygen vacancies on ferroelectric domains is responsible for the excellent ferroelectric polarization of KNNFC0.015 through the generation of an internal field to promote charge carriers separation and reduce nonradiative recombination.Importantly,the accompanying electron carriers can easily move to the material surface and participate in redox reactions because they have low activation energy.Therefore,ferroelectric polarization and defects play synergetic roles in enhancing piezocatalytic performance.

MiR-320e inhibits proliferation in human umbilical vein endothelial cells

Objective MicroR NAs(miRs)are a class of small non-coding RNAs,and have been shown to be critical regulators in pathology of cardiovascular disease,such as atherosclerosis,hypertension.We aimed to identify certain miR from differentially expressed miRs in coronary artery disease(CAD)patients and healthy controls,and to investigate its role in the pathology of CAD.

A thermo-responsive rewritable plasmonic bio-memory by regulating single core-satellite gold nanocluster dissociation

A thermo-responsive rewritable plasmonic bio-memory chip has been successfully fabricated on an indium tin oxide(ITO)glass slide by assembling core-satellite gold nanoclusters with different size of gold nanoparticles(AuNPs)using double-strand DNA(dsDNA)linker.And the prepared 70@DNA20@13 gold nanoclusters(AuNCs)exhibited more stable and greater photothermal conversion ability.With short time irradiation by 633 nm microbeam laser,every individual AuNCs could be excited and remove the satellite AuNPs on its surface.Especially,in the dissociation process of AuNCs with 3−5 satellite,its color would change from yellow to green,which showed more significant reduction in the red channel of the dark-field microscopy(DFM)images and could be defined to state“0”and“1”respectively.Besides,this plasmonic nano bio-memory could transform cyclically its state between 0 and 1 which exhibited excellent rewritable ability.

A Water-soluble Conjugated Polymer for Thiol Detection Based on ＂Tu rn-off＂ Effect

We investigated a novel water-soluble conjugated polymer （WSCP） for thiol detection based on ＂turn-off＂ ef- fect. This WSCP was modified with poly（ethylene glycol） （PEG） by disulfide linkages to achieve good solubility in aqueous solution （34 mg/mL） and high quantum yield （0.47）. The separation of water-soluble PEG chains from the conjugated backbone induced by the cleavage of the disulfide linkages would lead to a significant decrease of the water solubility and a dramatical fluorescence quenching of the probe. The combined intuitive images and fluores- cence spectrophotometer further confirmed that decreased solubility produced an aggregation of the hydrophobic conjugated backbone. The fluorescence intensity of the probe showed a good linear relationship with glutathione （GSH） （1-200 nmol·L^-1）, and the detection limit was 16 nmol·L^-1. This WSCP probe was confirmed to be a good sensing material with high selectivity to thiols by testing various biological molecules. And this WSCP probe ex- hibited good detection effect to intracellular thiols by testing Hela cells. Considering the good sensitivity and selec- tivity, the probe could be further used in vivo. In conclusion, this conjugated polymer probe made up for the draw- backs of the micromolecue probes and contributed to the development of new probes based on conjugated poly- mers.

Morphology-Tunable Fluorescent Nanoparticles： Synthesis, Photophysical Properties and Two-Photon Cell Imaging

A novel water-soluble fluorescent amphiphile based on amino polyethylene glycol （PEG-NH2） substituted oligo- （p-phenyleneethynylene） （OPE） was designed and synthesized successfully. Taking anion OPE amphiphile as a comparison, the photophysical features were investigated through ultraviolet absorption （UV） and photolumines- cence （PL） analyses. Due to the hydrophobic-hydrophilic property of the OPE conjugated molecule, self-assembled nanoparticles with the size ranging from 19.6 to 93.5 nm along with the change of morphology from ＂grain＂ to ＂strawberry＂ were conveniently prepared via adjusting concentrations of OPE aqueous solution. Interestingly, after aging for a period of time, homogeneous hollow nanospheres were spontaneously constructed with a diameter of about 200 rim. Cytotoxieity test and cellular uptake behavior of the nanoparticles were further investigated to evalu- ate their potential biomedical applications. Subsequently, the promising applications of two-photon cell imaging were explored using human pancreatic cancer cells （PANC-I cells）, which indicated that the nanoparticles were mainly located within the cell cytoplasm.

可激活的NIR-Ⅱ探针用于肿瘤成像

波长位于1000~1700 nm之间的近红外窗口,通常被称为第二近红外(NIR-Ⅱ)窗口,在生物成像方面(荧光成像、光声成像等),该窗口展现出强大的吸引力。相比在可见光(400~700 nm)区域和第一近红外(NIR-Ⅰ,700~900 nm)窗口的传统成像,NIR-Ⅱ生物成像提供了分辨率高和穿透深度深等优点。但是,目前大多数"always-on"探针,并不能实现更高的信噪比。肿瘤微环境响应型智能药物的成像只在肿瘤中触发,可以克服这一局限性。因此,应充分结合肿瘤微环境和NIR-Ⅱ智能响应探针,充分发挥两者的优势,提高肿瘤的精准诊断。本文从不同的病理参数综述了可激活的NIR-Ⅱ荧光探针在生物成像中的最新研究进展,并对这一新兴的领域所面临的机遇和挑战提出看法。

硼亲和可控定向表面分子印迹技术研究进展

分子印迹是一项模拟靶向生物分子特异性识别能力的仿生分子识别技术,因其识别选择性好、制备简单、价格低廉等优势而被广泛应用.发展至今,已有多种先进的印迹方法被报道,包括表面印迹、表位印迹、乳液印迹等,克服了传统本体印迹方法中存在的许多问题,也使分子印迹技术在许多应用领域成为理想的抗体替代品.由于糖抗体极为稀缺,因此发展出针对糖类化合物的分子印迹技术显得尤为重要,而硼亲和可控定向表面分子印迹技术的提出为解决该问题提供了极有力的技术支持.该技术是一项可控、通用、高效的分子印迹技术,几乎适用于各种类型的基质材料和所有糖类化合物的印迹.它的提出不仅进一步丰富了分子印迹技术的应用范围,更是从方法学上将分子印迹技术推向了一个新的高度,因此具有重要的现实与科学意义.本文介绍了硼亲和可控定向表面分子印迹技术的主要制备方法、原理、应用及其最新研究进展,提出了该技术目前存在的若干问题并展望其未来可能的发展方向.

Spontaneous immunomodulation and regulation of angiogenesis and osteogenesis by Sr/Cu-borosilicate glass (BSG) bone cement to repair critical bone defects

Injectable bone biomaterials like bone cement should be designed and fabricated with certain biological criteria,which include:1)recruitment and polarization of the macrophages from M1(pro-inflammatory)to M2(anti-inflammatory)phenotype,2)enhance vascularization,and 3)activate osteogenic differentiation of bone marrow-derived stem cells to promote bone healing.So far,no injectable biomaterials could spontaneously regulate the entire bone healing process that involves inflammation,angiogenesis,and osteogenesis.Therefore,in this study,we designed bone cement comprised of strontium and copper-incorporated borosilicate glass(Sr/Cu-BSG)in the liquid phase of chitosan to modulate bone healing.In vitro studies showed that the controlled release of Sr and Cu ions up-regulated anti-inflammatory genes(IL-1Ra and TGF-β1)while down-regulating pro-inflammatory genes(IL-1βand IL-6)in macrophages at 3 days.Sr and Cu ions also increased the expressions of angiogenic genes(VEGF and bFGF)in HUVECs at 5 days and osteogenic genes(Runx-2,OCN,and OPN)in hBMSCs at 7,14,and 21 days.5Sr3Cu-BSG bone cement exhibited the best anti-inflammatory,angiogenic,and osteogenic properties among the bone cement groups with different Sr and Cu ratios.Short-term and long-term implantation of Sr/Cu-BSGs in femoral condylar bone defects of rats and rabbits confirmed the in vitro results,where the degradation rate of Sr/Cu-BSG matched the bone healing rate.Similar to in vitro,the 5Sr3Cu-BSG group also showed the highest bone formation in vivo.Excellent physical and chemical properties,along with its bone repairing ability,make the Sr/Cu-BSG bone cement a good candidate biomaterial for treating bone defects.

Nanocrystals for large Stokes shift-based optosensing

Stokes shift is an important feature of fluorescence, which reveals the energy loss between the excitation and the emission. For most fluorescent materials(e.g., organic dyes and proteins), the large overlap between the absorption and emission spectra endow them a small Stokes shift that induced reabsorption by fluorophore itself. Although the self-absorption can be effectively reduced due to the emergence of fluorescent nanomaterials, fluorescence attenuation is still observed in aggregated or concentrated nanocrystals, causing reduced sensitivity of biosensors. Therefore, increasing the Stokes shift can effectively improve the performance of nano-agents based biosensing. In this critical review, through understanding the Stokes shift from the viewpoint of self-absorption, the influence of Stokes shift on fluorescence properties are discussed. Based on the principle of changing the Stokes shift of fluorescent nanomaterials, we described the methods for constructing various optically large Stokes shift-based nanomaterials, and the application of these nanocrystals in biosensing is especially concerned in this review.

Reversible acetylation modulates dishevelled-2 puncta formation in canonical Wnt signaling activation

Dear Editor,Dishevelled-2(DVL2)is a central adaptor protein that propagates signals from upstream receptors to downstream effectorβ-catenin in canonical Wnt signaling.At high local concentration,DVL2 assembles into signalosomes through DIX domain-mediated homo-polymerization to provide a docking platform for the recruitment of signaling components,which is critical for Wnt signaling transduction and activation;1 however,the exact underlying mechanism remains inconclusive.Although the roles of phosphorylation and ubiquitination in DVL2-puncta formation have been discussed before,2 the impact of lysine acetylation of DVL2 on this process remains elusive.Here we investigated the effect of acetylation on DVL2-puncta formation.

Confidence Measure of the Shallow-Water Bathymetry Map Obtained through the Fusion of Lidar and Multiband Image Data

With the advancement of Lidar technology,bottom depth(H)of optically shallow waters(OSW)can be measured accurately with an airborne or space-borne Lidar system(H_(Lidar) hereafter),but this data product consists of a line format,rather than the desired charts or maps,particularly when the Lidar system is on a satellite.Meanwhile,radiometric measurements from multiband imagers can also be used to infer H(H_(imager) hereafter)of OSW with variable accuracy,though a map of bottom depth can be obtained.It is logical and advantageous to use the two data sources from collocated measurements to generate a more accurate bathymetry map of OSW,where usually image-specific empirical algorithms are developed and applied.Here,after an overview of both the empirical and semianalytical algorithms for the estimation of H from multiband imagers,we emphasize that the uncertainty of H_(imager) varies spatially,although it is straightforward to draw regressions between H_(Lidar) and radiometric data for the generation of H_(imager).Further,we present a prototype system to map the confidence of H_(imager) pixel-wise,which has been lacking until today in the practices of passive remote sensing of bathymetry.We advocate the generation of a confidence measure in parallel with H_(imager),which is important and urgent for broad user communities.