Hitherto-Unexplored Photodynamic Therapy of Ag2S and Enhanced Regulation Based on Polydopamine In Vitro and Vivo

Given their superior penetration depths, photosensitizers with longer absorption wavelengths present broader application prospects in photodynamic therapy (PDT). Herein, Ag₂S quantum dots were discovered, for the first time, to be capable of killing tumor cells through the photodynamic route by near-infrared light irradiation, which means relatively less excitation of the probe compared with traditional photosensitizers absorbing short wavelengths. On modification with polydopamine (PDA), PDA-Ag₂S was obtained, which showed outstanding capacity for inducing reactive oxygen species (increased by 1.69 times). With the addition of PDA, Ag₂S had more opportunities to react with surrounding O₂, which was demonstrated by typical triplet electron spin resonance (ESR) analysis. Furthermore, the PDT effects of Ag₂S and PDA-Ag₂S achieved at longer wavelengths were almost identical to the effects produced at 660 nm, which was proved by studies in vitro. PDA-Ag₂S showed distinctly better therapeutic effects than Ag₂S in experiments in vivo, which further validated the enhanced regulatory effect of PDA. Altogether, a new photosensitizer with longer absorption wavelength was developed by using the hitherto-unexplored photodynamic function of Ag₂S quantum dots, which extended and enhanced the regulatory effect originating from PDA.     

Surface-enhanced Raman scattering study of polymer on metals. III. Chemisorbed polybenzimidazole and its corrosion-inhibiting properties at high temperature

Chemisorption of polybenzimidazole on silver and copper etched with nitric acid has been observed by surface-enhanced Raman scattering (SERS). The polymer is found to react chemically with silver, forming a complexed film on the surface. The SERS spectra show that polybenzimidazole film inhibits oxidation of the metal at high temperature, unlike chemisorbed benzimidazole, benzotriazole, and poly(4-vinyl pyridine). © 1992 John Wiley & Sons, Inc.     

THE RING OPENING REACTION OF AN EPOXY COMPOUND ON THE TOP OF CHEMISORBED CYSTAMINE STUDIED BY THE SERS TECHNIQUE

Metal foils for Raman scattering were prepared by HNO_3 etching method. These foils werefound to exhibit a strong SERS effect and excellent thermal stability. SERS spectra of cystaminehave been taken to illustrate the usefulness of this sample preparation method in the studies ofchemisorption. The ring opening reactions of an epoxy compound have been observed on the topof chemisorbed cystamine on silver foils.     

异烟酸在银溶胶上的表面增强喇曼散射及影响因素

本文研究了异烟酸吸附在银溶胶表面的表面增强喇曼散射(SERS)光谱以及卤素离子、溶液pH值及溶液浓度对异烟酸SERS光谱的影响。文章提出了离子在银溶胶表面的吸附方式,即主要以—COO~-端吸附于银溶胶表面。最后,对所述实验现象作了定性讨论。     

Boosted Photocurrent via Heating BiFeo3 Thin Film for UV Photodetector at Wide Temperature Range

The current research on ferroelectric photovoltaic materials is concentrated on enhancing the output photocurrent. As solar cells operate at high temperatures, it is crucial to take into account the effect of increasing temperatures on ferroelectric photovoltaics. In this study, an LNO (lanthanum nickelate, LaNiO₃)/BFO (bismuth ferrate, BiFeO₃)/ITO (indium tin oxide) device is constructed on a mica substrate by sol–gel method. The device achieves output photocurrent enhancement at a wide temperature range (33–183 °C), with the largest photocurrent enhancement at 130 °C, which is 178% relative to room temperature, and the output power is also increased by 9.88 times. At the same time, compared with BFO bulk, it is found that the performance of BFO film is always higher than that of bulk in the test temperature range, and the output photocurrent of BFO film at room temperature is 104 times higher than that of bulk. This article investigates the effect of high temperatures on ferroelectric photovoltaics and also provides a strategy for enhancing the photovoltaic performance of ferroelectric films, providing guidance for future applications of ferroelectric films in flexible solar cells and other applications.     

Clustering-based adaptive low-power subframe configuration with load-aware offsetting in dense heterogeneous networks

Heterogeneous Networks (HetNets) and cell densification represent promising solutions for the surging data traffic demand in wireless networks. In dense HetNets, user traffic is steered toward the Low-Power Node (LPN) when possible to enhance the user throughput and system capacity by increasing the area spectral efficiency. However, because of the transmit power differences in different tiers of HetNets and irregular service demand, a load imbalance typically exists among different serving nodes. To offload more traffic to LPNs and coordinate the Inter-Cell Interference (ICI), Third-Generation Partnership Project (3GPP) has facilitated the development of the Cell Range Expansion (CRE), enhanced Inter-Cell Interference Coordination (eICIC) and Further enhanced ICIC (FeICIC). In this paper, we develop a cell clustering-based load-aware offsetting and an adaptive Low-Power Subframe (LPS) approach. Our solution allows the separation of User Association (UA) functions at the User Equipment (UE) and network server such that users can make a simple cell-selection decision similar to that in the maximum Received Signal Strength (max-RSS) based UA scheme, where the network server computes the load-aware offsetting and required LPS periods based on the load conditions of the system. The proposed solution is evaluated using system-level simulations wherein the results correspond to performance changes in different service regions. Results show that our method effectively solves the offloading and interference coordination problems in dense HetNets.     

Determination of heavy metal concentration in feed and permeate streams of polymer enhanced ultrafiltration process

Polymer enhanced ultrafiltration (PEUF) is a newly developed method for the removal of heavy metals from aqueous solutions. This method was applied for the removal of mercury and cadmium with the presence of polyethyleneimine (PEI) as a water soluble polymer. After ultrafiltration experiments for metal–polymer mixtures, two separate streams, namely, retentate and permeate, former of which contains mainly metal–polymer complex and free polymer molecules while latter of which mainly contains free metal ions, were obtained. At the end of PEUF experiments, performance of operation was determined by concentration analyses which was achieved by atomic absorption spectroscopy (AAS) applied in a different way for permeate and retentate streams considering the effect of presence of polymer. For mercury analysis, cold vapor AAS was applied. It was observed that the presence of PEI did not affect the atomic absorption signal when 10% HCl was added to the sample solutions. For calcium and cadmium, flame AAS was used. It was observed that change in PEI concentration results in change in measured concentration of calcium and cadmium. Therefore, two new approaches were developed for accurate measurement of concentrations of calcium and cadmium. It was also observed that presence of other metals did not affect the accuracy of the measurement of a particular metal in the concentration range studied.     

金属离子对中位─四（4─N甲氧羰甲基吡啶）卟啉表面增强拉曼光谱的影响

研究了金属离子对吸附在银胶表面的中位－四（４－Ｎ甲氧羰甲基吡啶）卟啉表面增强拉曼光谱的影响。结果表明，中位－四（４－Ｎ甲氧羰甲基吡啶）卟啉可发生金属离子取代反应。金属离子嵌入卟啉大环，吸附在银胶表面的中位－四（４－Ｎ甲氧羰甲基吡啶）卟啉转变为金属配合物。给出了各种金属配合物主要拉曼峰的经验式归属。金属离子的半径，ｄ电子对卟啉环的排斥作用，金属卟啉骨架模式频率随孔穴大小，大环的平面性和π－π相互作用而相应变化的特性，都可用来解释不同金属离子配合物的结构灵敏特征峰为何存在着差异。