A Biomimetic Nanoparticle to “Lure and Kill” Phospholipase A2

Inhibition of phospholipase A2 (PLA2) has long been considered for treating various diseases associated with an elevated PLA2 activity. However, safe and effective PLA2 inhibitors remain unavailable. Herein, we report a biomimetic nanoparticle design that enables a “lure and kill” mechanism designed for PLA2 inhibition (denoted “L&K-NP”). The L&K-NPs are made of polymeric cores wrapped with modified red blood cell membrane with two inserted key components: melittin and oleyloxyethyl phosphorylcholine (OOPC). Melittin acts as a PLA2 attractant that works together with the membrane lipids to “lure” in-coming PLA2 for attack. Meanwhile, OOPC acts as inhibitor that “kills” PLA2 upon enzymatic attack. Both compounds are integrated into the L&K-NP structure, which voids toxicity associated with free molecules. In the study, L&K-NPs effectively inhibit PLA2-induced hemolysis. In mice administered with a lethal dose of venomous PLA2, L&K-NPs also inhibit hemolysis and confer a significant survival benefit. Furthermore, L&K-NPs show no obvious toxicity in mice. and the design provides a platform technology for a safe and effective anti-PLA2 approach.     

The (010) Surface of the Al45Cr7 Complex Intermetallic Compound: Insights from Density Functional Theory

The Al₄₅Cr₇ compound is considered to exhibit an approximant structure of the icosahedral Al₄Cr phase. Its (010) surface has been investigated in detail using density functional calculations. Surface energy calculations show that the stable terminations result from a cleavage of the crystal between adjacent atomic planes, in agreement with the layered structure of the compound. The integrity of the icosahedral atomic arrangements (icosahedral clusters) found in the bulk structure, is predicted to be removed at the surface. This result is in contrast to what has been previously concluded for the (010) surface of the Al₁₃Fe₄ quasicrystal approximant. Our findings are discussed in relation to the bonding network in the compound, calculated using the Crystal Orbital Hamiltonian Population approach, as possible reasons for such contrasted behavior.     

A Sensor for Serotonin and Dopamine Detection in Cancer Cells Line Based on the Conducting Polymer−Pd Complex Composite

An electrochemical sensor based on the conducting polymer composite with a palladium complex (Pd(C₂H₄N₂S₂)₂) was developed for the detection of serotonin and dopamine simultaneously in the breast cancer cell and human plasma samples. The proposed sensor was fabricated using the Pd(C₂H₄N₂S₂)₂ complex‐anchored poly2,2 : 5,2‐terthiophene‐3‐(p‐benzoic acid) (pTBA) layer on the AuNPs decorated reduced graphene oxide (AuNPs@rGO) substrate, which revealed the enhanced anodic current of the target species. The sensor probe was characterized by electrochemical and surface analysis methods. The experimental parameters affecting the sensor performance were optimized, in terms of AuNPs@rGO concentration, the number of electropolymerization cycle for pTBA, immobilization time of Pd(C₂H₄N₂S₂)₂, and pH. The dynamic ranges for serotonin and dopamine were obtained from 0.02 to 200 μM, and from 0.1 to 200 μM with the detection limit of 2.5, and 24.0 nM, respectively. The reliability of proposed sensor was evaluated using cancer cell lines for the clinical applications.     

Reducing Agents for Improving the Stability of Sn‐based Perovskite Solar Cells

Organic‐inorganic hybrid perovskite solar cells (PSCs) have aroused tremendous research interest for their high efficiency, low cost and solution processability. However, the involvement of toxic lead in state‐of‐art perovskites hinders their market prospects. As an alternative, Sn‐based perovskites exhibit similar semiconductor characteristics and can potentially achieve comparable photovoltaic performance in comparison with their lead‐based counterparts. The main challenge of developing Sn‐based PCSs lies in the intrinsic poor stability of Sn²⁺, which could be oxidized and converted to Sn⁴⁺. Notably, introduction of SnX₂ (X=Cl, Br, I) additive becomes indispensable in the fabrication process, which highlights the importance of incorporating a reducing agent to improve the device stability. Additionally, efforts are made to utilize other reducing agents with different functions for the further enhancement of device performance. Currently, Sn‐based PSCs could attain a record efficiency over 10% with great stability. In this review, we present the recent progress on reducing agents for improving the stability of Sn‐based PSCs, and we hope to shed light on the challenges and opportunities of this research field.     

准一维电荷密度波材料Ta2NiSe7 的转角及变温拉曼光谱研究

近年来, 低维过渡金属硫族化合物Ta2NiSe7 因其独特的电荷密度波和特殊的拓扑能带结构而引起广泛关注. 本文利用拉曼光谱技术对准一维电荷密度波材料Ta2NiSe7 的声子模式进行了系统研究. 角度依赖的偏振拉曼光谱实验表明室温下可以观测到19 个拉曼峰, 且所有观察到的拉曼模式强度随样品旋转呈周期性变化, 这意味着Ta2NiSe7 具有较高的面内各向异性. 通过群论分析, 我们确定了拉曼峰的具体模式为Ag 和Bg 两种原子振动模式. 在温度依赖的偏振拉曼光谱测量中, 我们在低温下还观察到了新的声子峰, 推测与电荷密度波结构调制引起的晶格畸变有关. 本研究提供了对Ta2NiSe7 声子振动的全面理解, 这可能为进一步研究电荷密度波与声子振动之间的关联提供参考意义.     

Alkaline Stable Anion Exchange Membranes Based on Cross-Linked Poly(arylene ether sulfone) Bearing Dual Quaternary Piperidines for Enhanced Anion Conductivity at Low Water Uptake

Alkaline stable anion exchange membranes based on the cross-linked poly(arylene ether sulfone) grafted with dual quaternary piperidine (XPAES-DP) units were synthesized. The chemical structure of the synthesized PAES-DP was validated using ¹H-NMR and FT-IR spectroscopy. The physicochemical, thermal, and mechanical properties of XPAES-DP membranes were compared with those of two linear PAES based membranes grafted with single piperidine (PAES-P) unit and conventional trimethyl amine (PAES-TM). XPAES-DP membrane showed the ionic conductivity of 0.021 S cm⁻¹ at 40 °C which was much higher than that of PAES-P and PAES-TM because of the possession of more quaternary ammonium groups in the cross-linked structure. This cross-linked structure of the XPAES-DP membrane resulted in a higher tensile strength of 18.11 MPa than that of PAES-P, 17.09 MPa. In addition, as the XPAES-DP membrane shows consistency in the ionic conductivity even after 96 h in 3 M KOH solution with a minor change, its chemical stability was assured for the application of anion exchange membrane fuel cell. The single-cell assembled with XPAES-DP membrane displayed a power density of 109 mWcm⁻² at 80 °C under 100% relative humidity.     

Sensing the Anti-Epileptic Drug Perampanel with Paper-Based Spinning SERS Substrates

The applications of SERS in therapeutic drug monitoring, or other fields of analytical chemistry, require the availability of sensitive sensors and experimental approaches that can be implemented in affordable ways. In this contribution, we show the production of cost-effective SERS sensors obtained by depositing Lee-Meisel Ag colloids on filter paper either by natural sedimentation or centrifugation. We have characterized the morphological and plasmonic features of the sensors by optical microscopy, SEM, and UV-Vis spectroscopy. Such sensors can be used to quantify by SERS the anti-epileptic drug Perampanel (in the concentration range 1 × 10⁻⁴–5 × 10⁻⁶ M) by spinning them during the micro-Raman measurements on the top of a custom device obtained from spare part hard disk drives. This approach minimizes laser-induced heating effects and allows averaging over the spatial non-uniformity of the sensor.     

基于神经网络的钞票真假识别研究

利用神经网络与光电检测的技术研制了钞票真假识别系统.介绍了系统的结构组成、工作原理、软件系统、神经网络的优化设计、实验及测试结果.经实践验证,其识别结果稳定可靠,可应用于金融智能防伪点钞机与ATM机中.     

Phytochemical Analysis,Antioxidant, and Wound Healing Activity of Pluchea indica L. (Less) Branch Extract Nanoparticles

Proliferation and migration of keratinocytes and fibroblasts play an important role in cutaneous wound healing, while oral mucosal squamous cell proliferation and migration are crucial for oral wound healing. In this study, the phytochemical profile of Pluchea indica branch ethanolic extract was characterized. The bioactive compound of Pluchea indica branch ethanolic extract was identified and analyzed by the validated HPLC method. The nanoparticles of P. indica branch extract were formulated by solvent displacement method to increase the solubility and the colloidal stability of the extract. The stability of the nanoparticles was investigated by using the dynamic light scattering technique. Effects of P. indica crude extract and nanoparticles on cell viability, proliferation and migration of primary epidermal keratinocytes, human dermal fibroblasts, and oral mucosal keratinocyte cells were investigated by MTT assay and scratch assay, respectively. The results showed that P. indica branch extract contained a high content of total phenolic and total flavonoids. The HPLC analysis revealed that the main compound in the extract was 4,5-O-dicaffeoylquinic acid. The cell viability of the extract and nanoparticles decreased when cells were exposed to a high concentration of extract and nanoparticles. These results demonstrate that P. indica branch extract and extract nanoparticles at specific concentrations possess in vitro wound healing activity and they may be possibly used to treat different types of wounds including dermal and oral mucosal wounds.     

Use of TLC-Densitometric Method for Determination of Valproic Acid in Capsules

Determination of valproic acid in the drug was carried out on the aluminum silica gel 60F₂₅₄ plates and using acetone–water–chloroform–ethanol–ammonia at a volume ratio of 30:1:8:5:11 as the mobile phase, respectively. Two methods of detection of valproic acid were used. The first was a 2% aqueous CuSO₄×5H₂O solution, and the second was a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system. The applied TLC-densitometric method is selective, linear, accurate, precise, and robust, regardless of the visualizing reagent used for the determination of valproic acid in Convulex capsules. It has low limits of detection (LOD) and limits of quantification (LOQ), which are equal to 5.8 μg/spot and 17.4 μg/spot using a 2% aqueous CuSO₄×5H₂O solution as visualizing agent and also 0.32 μg/spot and 0.97 μg/spot using a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system as visualizing reagent, respectively. The described analytical method can additionally be used to study the identity of valproic acid in a pharmaceutical preparation. The linearity range was found to be 20.00–80.00 μg/spot and 1.00–2.00 μg/spot for valproic acid detected on chromatographic plates using a 2% aqueous CuSO₄×5H₂O solution and the 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system, respectively. A coefficient of variation that was less than 3% confirms the satisfactory accuracy and precision of the proposed method. The results of the assay of valproic acid equal 96.2% and 97.0% in relation to the label claim that valproic acid fulfill pharmacopoeial requirements. The developed TLC-densitometric method can be suitable for the routine analysis of valproic acid in pharmaceutical formulations. The proposed TLC-densitometry may be an alternative method to the modern high-performance liquid chromatography and square wave voltammetry in the control of above-mentioned substances, and it can be applied when other analytical techniques is not affordable in the laboratory.