Micromechanical Properties of Microstructured Elastomeric Hydrogels

Local, micromechanical environment is known to influence cellular function in heterogeneous hydrogels, and knowledge gained in micromechanics will facilitate the improved design of biomaterials for tissue regeneration. In this study, a system comprising microstructured resilin‐like polypeptide (RLP)–poly(ethylene glycol) (PEG) hydrogels is utilized. The micromechanical properties of RLP‐PEG hydrogels are evaluated with oscillatory shear rheometry, compression dynamic mechanic analysis, small‐strain microindentation, and large‐strain indentation and puncture over a range of different deformation length scales. The measured elastic moduli are consistent with volume averaging models, indicating that volume fraction, not domain size, plays a dominant role in determining the low strain mechanical response. Large‐strain indentation under a confocal microscope enables the visualization of the microstructured hydrogel micromechanical deformation, emphasizing the translation, rotation, and deformation of RLP‐rich domains. The fracture initiation energy results demonstrate that failure of the composite hydrogels is controlled by the RLP‐rich phase, and their independence with domain size suggested that failure initiation is controlled by multiple domains within the strained volume. This approach and findings provide new quantitative insight into the micromechanical response of soft hydrogel composites and highlight the opportunities in employing these methods to understand the physical origins of mechanical properties of soft synthetic and biological materials.     

Single‐Molecule Redox‐Targeting Reactions for a pH‐Neutral Aqueous Organic Redox Flow Battery

Aqueous organic redox flow batteries (AORFBs) have received considerable attention for large‐scale energy storage. Quinone derivatives, such as 9,10‐anthraquinone‐2,7‐disulphonic acid (2,7‐AQDS), have been explored intensively owing to potentially low cost and swift reaction kinetics. However, the low solubility in pH‐neutral electrolytes restricts their application to corrosive acidic or caustic systems. Herein, the single molecule redox‐targeting reactions of 2,7‐AQDS anolyte are presented to circumvent its solubility limit in pH‐neutral electrolytes. Polyimide was employed as a low‐cost high‐capacity solid material to boost the capacity of 2,7‐AQDS electrolyte to 97 Ah L^?1. Through in situ FTIR spectroscopy, a hydrogen‐bonding mediated reaction mechanism was disclosed. In conjunction with NaI as catholyte and nickel hexacyanoferrate as the catholyte capacity booster, a single‐molecule redox‐targeting reaction‐based full cell with energy density up to 39 Wh L^?1 was demonstrated.     

Peptide‐Conjugated Long‐Lived Theranostic Imaging for Targeting GRPr in Cancer and Immune Cells

Gastrin‐releasing peptide receptor (GRPr) plays proliferative and inflammatory roles in living systems. Here, we report a highly selective GRPr antagonist (JMV594)‐tethered iridium(III) complex for probing GRPr in living cancer cells and immune cells. This probe exhibited desirable photophysical properties and also displayed negligible cytotoxicity, overcoming the inherent toxicity of the iridium(III) complex. Its long emission lifetime enabled its luminescence signal to be readily distinguished from the interfering fluorescence of organic dyes by using a time‐resolved technique. This probe selectively visualized living cancer cells via specific binding to GRPr, while it also modulated the function of GRPr on TNF‐α secretion in immune cells. To our knowledge, this is the first peptide‐conjugated iridium(III) complex developed as a GRPr bioimaging probe and modulator of GRPr activity. This theranostic agent shows great potential at unmasking the diverse roles of GRPr in living systems.     

Stabilization of the Closed-Ring Isomer of Spiropyran by Amide Naphthotube in Water and Its Application in Naked-Eye Detection of Toxic Paraoxon

The thermodynamically unstable, colourless closed-ring isomer of spiropyran can be stabilized in water by the anti-configurational isomer of amide naphthotube. The influence of the binding on the thermodynamics and kinetics of spiropyran have been studied. The complex was further used to prepare a test paper that allows naked-eye detection of toxic paraoxon.     

Understanding energetic disorder in electron-deficient-core-based non-fullerene solar cells

Recent advances in material design for organic solar cells(OSCs) are primarily focused on developing near-infrared nonfullerene acceptors, typically A-DA′D-A type acceptors(where A abbreviates an electron-withdrawing moiety and D, an electron-donor moiety), to achieve high external quantum efficiency while maintaining low voltage loss. However, the charge transport is still constrained by unfavorable molecular conformations, resulting in high energetic disorder and limiting the device performance. Here, a facile design strategy is reported by introducing the "wing"(alkyl chains) at the terminal of the DA′D central core of the A-DA′D-A type acceptor to achieve a favorable and ordered molecular orientation and therefore facilitate charge carrier transport. Benefitting from the reduced disorder, the electron mobilities could be significantly enhanced for the"wing"-containing molecules. By carefully changing the length of alkyl chains, the mobility of acceptor has been tuned to match with that of donor, leading to a minimized charge imbalance factor and a high fill factor(FF). We further provide useful design strategies for highly efficient OSCs with high FF.     

Selective Synthesis of Z‐Cinnamyl Ethers and Cinnamyl Alcohols through Visible Light‐Promoted Photocatalytic E to Z Isomerization

A photocatalytic E to Z isomerization of alkenes using an iridium photosensitizer under mild reaction conditions is disclosed. This method provides scalable and efficient access to Z‐cinnamyl ether and allylic alcohol derivatives in high yields with excellent stereoselectivity. Importantly, this method also provides a powerful strategy for the selective synthesis of Z‐magnolol and honokiol derivatives possessing potential biological activity.     

柱前衍生高效液相色谱法测定四氢噻唑-2-硫酮-4-羧酸的光学纯度

用苯胺对四氢噻唑-2-硫酮-4-羧酸(TTCA)进行柱前衍生,将其衍生物在手性固定相上拆分,通过二极管阵列紫外检测器和在线旋光检测仪对其衍生物进行检测,建立了一种拆分TTCA消旋体、测定TTCA光学纯度的新方法。以正己烷和乙醇或异丙醇为流动相,在DNB-Leucine手性固定相上对TTCA衍生物进行了拆分,并考察了流动相组成和柱温对其衍生物分离的影响,获得较优分析条件,分离因子大于1.2。非手性试剂苯胺柱前衍生化法测定(R)-TTCA的光学纯度与旋光度方法比较,结果一致,相对偏差小于1.34%。     

DMFC两相流及其对传质影响的研究

采用自制的实验系统对液态进料直接甲醇燃料电池(DMFC)阳极交叉指状流道内的两相况功特性进行了可视化实验研究.自制的DMFC单电池带有透明窗口,采用镀金的不锈钢阴极极板和透明的聚碳酸脂阳极流场板,电解质为Nafion117膜.实验过程中燃料电池的进口总管和出口总管是水平的,进口流道和出口流道是竖直的.实验发现,出口流道中典型的两相流流型是泡状流、而出口总管中的典型流型是弹状流.进口流道中的气弹和气柱导致了阳极传质恶化.     

共焦显微拉曼光谱技术在墨迹鉴定方面的应用

利用共焦显微拉曼光谱技术,用可见514.5nm和紫外325nm激光器作激发光源,分别测试了不同品牌的黑色圆珠笔,蓝色圆珠笔和黑色签字笔墨迹的拉曼谱图。在可见514.5nm激光器的激发下,黑色和蓝色圆珠笔墨迹都呈现了丰富的拉曼特征峰而黑色签字笔仅出现了碳峰的信号;此时改换325nm激光器来激发,发现黑色签字笔墨迹出现了清晰的拉曼特征谱峰。通过实验数据对比发现:同一类型且不同品牌笔的墨迹拉曼特征谱峰也存在一定的差异,同一种品牌墨迹的拉曼峰都保持了相对的稳定性。实验结果将为鉴定签字笔和圆珠笔油墨种类提供了法庭科学依据。它的最大优点就在于对样品的无损性,其次还有快速、无需对样品预处理和测试方法简单等。     

Sobolev-Lorentz范数约束下的次临界型Adams不等式

本文在Sobolev-Lorentz空间W2L2,q(R4)的范数约束下得到了一个最佳的二阶次临界型Adams不等式.进一步,当次临界指标逼近最佳常数时,得到了Adams泛函的上、下界的估计.本文主要采用了Lam和Lu[A new approach to sharp Moser-Trudinger and Adams ...