Chip-On-Valve Concept: An Integrated Platform for Multisyringe Flow Injection Analysis: Application to Nitrite and Nitrate Determination in Seawater

A state-of-the-art flow lab-on-a-valve technique is reported incorporating integration of flow devices such as reaction and mixing serpentine coils and confluences into a monolith flow circuit mounted directly on an eight-port selection valve. The potential of the flow circuit manifold or chip-on-valve in combination with multisyringe flow injection analysis is demonstrated by the application to the successful determination of nitrite and nitrate in seawater. Characteristics and further potential of chip-on-valve are discussed. Due to preparation and fabrication by use of computer aided design, this chip design shows great potential for the automation of sophisticated flow networks in compact and robust flow circuits.     

Sustainable Approaches Using Green Technologies for Apple By-Product Valorisation as A New Perspective into the History of the Apple

The apple has been recognised as the most culturally important fruit crop in temperate land areas. Centuries of human exploitation and development led to the production of thousands of apple cultivars. Nowadays, the apple represents the third most widely cultivated fruit in the world. About 30% of the total production of apples is processed, being juice and cider the main resulting products. Regarding this procedure, a large quantity of apple by-product is generated, which tends to be undervalued, and commonly remains underutilised, landfilled, or incinerated. However, apple by-product is a proven source of bioactive compounds, namely dietary fibre, fatty acids, triterpenes, or polyphenols. Therefore, the application of green technologies should be considered in order to improve the functionality of apple by-product while promoting its use as the raw material of a novel product line. The present work provides a holistic view of the apple’s historical evolution, characterises apple by-product, and reviews the application of green technologies for improving its functionality. These sustainable procedures can enable the transformation of this perishable material into a novel ingredient opening up new prospects for the apple’s potential use and consumption.     

反相流动注射-紫外光还原-分光光度法测定饮用水中的硝酸盐

1引言硝酸盐广泛存在于各种环境水体中。当饮用水中硝酸盐浓度过高时,可能对人体健康造成危害;地表水中硝酸盐大量积累,则可能引起藻类过度繁殖,溶解氧耗竭,水质恶化。目前,检测硝酸盐的最常用方法是将硝酸盐还原为亚硝酸盐,再经重氮偶联反应后由分光光度法进行测定[1]。此类方法已较好地与流动分析技术相结合,广泛应用于测定环境样     

The Use of Low Field NMR and Thermal Analysis to the Wood Polymer Composite Study

Summary: The focus of this work was to characterize the molecular dynamic of High Impact Polystyrene (HIPS - 5% PB), wood - A (Vochysia divergens) and B (Erisma uncinatum) - and their composites, using solid state nuclear magnetic resonance (NMR), by measuring the proton spin-lattice relaxation time (T₁H) using a low field NMR, and by thermal analysis as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). DSC and TGA measurements show that both woods present the same molecular behavior. On the other hand, the spin-lattice relaxation time observed that the water is interfering in the packing and arrangements of cellulose chains due to inter and intra hydrogen molecular interactions, promoting the T₁H values changed to high values. T₁H shows that the sample B presents a higher rigidity than sample A. However, HIPS presents higher T₁H values comparing to wood types. Analyzing the relaxation data for the composites, the values indicate that composites present an interaction between both components.     

Fabrication and Use of Dual‐function Iridium Oxide Coated Gold SECM Tips. An Application to pH Monitoring above a Copper Electrode Surface during Nitrate Reduction.

The fabrication of a gold microelectrode modified with iridium oxide film (IrO_x) and its use as tip with a dual function in SECM experiments is reported. The defective structure of the coating onto the microelectrode surface was used as strategy to combine the advantages of both amperometric (for current‐distance determination) and potentiometric (for pH sensing) SECM operation modes. Approach curves, using oxygen and hexaammineruthenium(III) as redox mediators, were obtained without significant loss of the performance and reproducibility of the potentiometric pH response. This allowed the precise positioning of the proposed tip above a substrate in SECM experiments and, subsequently, to monitor pH at the substrate surface. The IrO_x modified microelectrode was applied successfully in SECM experiments involving the local proton consumption during the nitrate reduction at a copper cathode surface.     

A Review on Bioengineering Approaches to Insulin Delivery: A Pharmaceutical and Engineering Perspective

Diabetes mellitus (DM) is the most prevalent non‐contagious disease, which has affected a large number of people all over the world. Among all treatments known to have a positive influence in the control of DM, insulin therapy is the most common and effective one. Nowadays, various methods of insulin delivery are under investigation, which are able to reach a plausible bioavailability with ignorable side effects instead of insulin injection. This article presents a comprehensive review of the insulin therapy approach with a focus on modified methods in insulin delivery strategies and current advances in engineered insulin delivery systems.     

Modern Theoretical Approaches to Modeling the Excited-State Intramolecular Proton Transfer: An Overview

The excited-state intramolecular proton transfer (ESIPT) phenomenon is nowadays widely acknowledged to play a crucial role in many photobiological and photochemical processes. It is an extremely fast transformation, often taking place at sub-100 fs timescales. While its experimental characterization can be highly challenging, a rich manifold of theoretical approaches at different levels is nowadays available to support and guide experimental investigations. In this perspective, we summarize the state-of-the-art quantum-chemical methods, as well as molecular- and quantum-dynamics tools successfully applied in ESIPT process studies, focusing on a critical comparison of their specific properties.     

Approaches to the Potential Therapy of COVID-19: A General Overview from the Medicinal Chemistry Perspective

In spite of advances in vaccination, control of the COVID-19 pandemic will require the use of pharmacological treatments against SARS-CoV2. Their development needs to consider the existence of two phases in the disease, namely the viral infection and the inflammatory stages. The main targets for antiviral therapeutic intervention are: (a) viral proteins, including the spike (S) protein characteristic of the viral cover and the viral proteases in charge of processing the polyprotein arising from viral genome translation; (b) host proteins, such as those involved in the processes related to viral entry into the host cell and the release of the viral genome inside the cell, the elongation factor eEF1A and importins. The use of antivirals targeted at host proteins is less developed but it has the potential advantage of not being affected by mutations in the genome of the virus and therefore being active against all its variants. Regarding drugs that address the hyperinflammatory phase of the disease triggered by the so-called cytokine storm, the following strategies are particularly relevant: (a) drugs targeting JAK kinases; (b) sphingosine kinase 2 inhibitors; (c) antibodies against interleukin 6 or its receptor; (d) use of the traditional anti-inflammatory corticosteroids.     

Computational Approaches: An Underutilized Tool in the Quest to Elucidate Radical SAM Dynamics

Enzymes are biological catalysts whose dynamics enable their reactivity. Visualizing conformational changes, in particular, is technically challenging, and little is known about these crucial atomic motions. This is especially problematic for understanding the functional diversity associated with the radical S-adenosyl-L-methionine (SAM) superfamily whose members share a common radical mechanism but ultimately catalyze a broad range of challenging reactions. Computational chemistry approaches provide a readily accessible alternative to exploring the time-resolved behavior of these enzymes that is not limited by experimental logistics. Here, we review the application of molecular docking, molecular dynamics, and density functional theory, as well as hybrid quantum mechanics/molecular mechanics methods to the study of these enzymes, with a focus on understanding the mechanistic dynamics associated with turnover.     

HUMANN-based system to identify benzimidazole fungicides using multi-synchronous fluorescence spectra: An ensemble approach

In this paper, we approach, using neural computation and ensemble systems, a pattern classification problem in fluorescence spectrometry, the resolution of difficult multi-fungicide mixtures (overlapping), specifically the benzimidazole fungicides, benomyl, carbendazim, thiabendazole and fuberidazole. These fungicides are compounds of an important environmental interest. Because of this, from an analytical point of view, it is interesting to develop sensitive, selective and simple methods for their determination. Fluorescence spectrometry has proven to be a sensitive and selective technique for determination of many compounds of environmental interest, but in some cases it is not enough. HUMANN is a hierarchical, unsupervised, modular, adaptive neural net with high biological plausibility, which has shown to be suitable for identification of these fungicides and organochlorinated compounds of environmental interest. We propose two modular artificial intelligent systems, with a structure of pre-processing and processing stage, a multi-input HUMANN-based system, using multi-fluorescence spectra as input to the system, and a HUMANN-ensemble system. We analyze the optimal configuration of inputs and the ensemble in order to obtain better results. We study such figures as precision and sensitivity of the method. Our proposal is a smart, flexible and effective complementary method, which allows reducing the analytical and/or computational complexity of the analysis. Figure Stages in identification of benzimidazole fungicides Based on a contribution presented at the XIII International Symposium on Luminescence Spectrometry held in Bologna, Italy from Sept. 7–11, 2008.     

理解全球化：基于“经济−社会−政治”体系共生演化视角的分析

20世纪80年代以来,一波超级全球化席卷全球。当今世界进入了百年未有之大变局,全球化陷入困境。应当如何理解当前的全球化困境？百年未有之大变局究竟变在何处？为此,可以从经济学、政治学、社会学与国际关系的综合视角,构建“经济−社会−政治”为一体的、动态演化的框架,以理解当今世界全球化的深层次矛盾。近一波全球化过程中全球经济力量与收入分配格局发生了变化,出现了发达经济体的经济停滞和新兴经济体的赶超,也导致了社会各阶层和不同社会群体的收入和财富差距发生巨变。全球化中全球经济基础的变化,即全球化中的全球经济力量格局变迁与收入分配恶化将对各国的经济和社会基础产生重大影响,进而影响上层建筑：国家的主导思想和意识形态。一个国家在国际关系和经济政策领域主导思想的演变,势必影响其对外战略和政策选择,进而影响本国的经济走向乃至全球化的历史进程。     

From Saturated BN Compounds to Isoelectronic BN/CC Counterparts: An Insight from Computational Perspective

In the present study, the inorganic analogues of alkanes as well as their isoelectronic BN/CC counterparts that bridge the gap between organic and inorganic chemistry are comparatively studied on the grounds of static DFT and Car–Parrinello molecular dynamics simulations. The BN/CC butanes CH₃CH₂BH₂NH₃, BH₃CH₂NH₂CH₃, and NH₃CH₂BH₂CH₃ were considered and compared with their isoelectronic counterparts NH₃BH₂NH₂BH₃ and CH₃CH₂CH₂CH₃. In addition, systematical replacement of the NH₂BH₂ fragment by the isoelectronic CH₂CH₂ moiety is studied in the molecules H₃N(NH₂BH₂)_3–m(CH₂CH₂)_mBH₃ (for m=0, 1, 2, or 3) and H₃N(NH₂BH₂)_2–m(CH₂CH₂)_mBH₃ (for m=0, 1, or 2). The DFT and Car–Parrinello simulations show that the isosteres of the BN/CC butanes CH₃CH₂BH₂NH₃, BH₃CH₂NH₂CH₃, and NH₃CH₂BH₂CH₃ and of larger oligomers of the type (BN)_k(CC)_l where k≥l are stable compounds. The BN/CC butane H₃NCH₂CH₂BH₃ spontaneously produces molecular hydrogen at room temperature. The reaction, prompted by very strong dihydrogen bonding NH???HB, undergoes through the neutral, hypervalent, pentacoordinated boron dihydrogen complex R?BH₂(H₂) [R=(CH₂CH₂)_nNH₂]. The calculations suggest that such intermediate and the other BN/CC butanes CH₃CH₂BH₂NH₃, BH₃CH₂NH₂CH₃, and NH₃CH₂BH₂CH₃ as well as larger BN/CC oligomers are viable experimentally. A simple recipe for the synthesis of CH₃CH₂BH₂NH₃ is proposed. The strength of the dihydrogen bonding appeared to be crucial for the overall stability of the saturated BN/CC derivatives.     

Structural Dynamics of Some Large-Ring Cyclodextrins. A Molecular Dynamics Study: An Analysis of Force Field Performance

Molecular dynamics simulations were performed on four large ring cyclodextrins (LR-CDs), CD14, CD21, CD26 and CD28, both in gas phase and in water solution. Four different force fields (parm94, parm99, glycam2000a and MM3*) were used to examine their dependence with the results. The differences were not significant when parm99 and glycam2000a were used. Parm94 and MM3* results differ considerably due to inadequate bending parameters (parm94) or due to a strong stabilization by the intramolecular hydrogen bonds between hydroxyl groups. Simulations in the gas phase show that the CDs are elongated and twisted, and that cavities typical for the native CDs (CDn, n = 6, 7, 8) are not present. Simulations in water solution produced average structures that do not correspond to the conformations in the crystalline state. The LR-CDs are highly flexible and this could favor the formation of inclusion complexes through the intermediation of some other molecules that could fit to the smaller and more specific cavities they have.On sabbatical leave from the Institute of Organic Chemistry with Center of Phytochemistry, Bulgarian Academy of Science, ul. Acad. G. Bonchev, bloc 9, 1113 Sofia, Bulgaria     

家国关系：理解近代以来中国基层治理变迁的一个视角

家国关系是理解20世纪中国基层治理逻辑变迁的重要本土视角。在传统社会,由于家国一体与家国同构,维系家族内部的伦理和结构就是维系国家统治的合法性和社会秩序。然而,近代以来,面对巨大的民族危机,国家却必须打破以家族为本位的社会结构,以社会成员的国族意识代替其家族意识,进而汲取更多的社会资源并进行有效的社会动员。随着家国关系由统一走向对立,国家能力实现了增长,但传统乡村以自治与德治为内容的治理模式也被彻底改变。在这种历史发展的基础之上,新时代的乡村治理需要妥善处理好国家能力增长与基层治理活力保持之间的平衡关系,探索基层自治、德治与法治在新的社会条件下的实现形式和有效融合机制。     

Computational evaluation of mass filter acceptance and transmittance influenced by developing fields: An application of the plane method to investigate prefilter efficacy for rectangular wave operated mass filters

The acceptance of quadrupole mass filters is improved when the alternating current (AC) and direct current (DC) fields are developed separately. Physically, this is achieved when a short RF only quadrupole (prefilter) is situated directly ahead of the mass filter. The acceptance gained by a system operating with a prefilter can be observed as an increase in sensitivity over conventional operation. Frequency dynamic duty cycle based rectangular waveform driven (rectangular wave) mass filters, a recent development, currently do not operate with prefilters. Little is known about the influence of duty cycle changes on the acceptance of rectangular wave mass filters. The sensitivity gain seen by conventional systems operating with prefilters indicates that the sensitivity of duty cycle based rectangular wave systems should increase comparably. The objective of this work was to determine prefilter efficacy for nonspecific rectangular wave mass filter systems. In this work, the plane method of acceptance was used to model the change to the acceptance and transmittance of sine and rectangular waveform driven mass filters under different modes of field development. Both systems indicated a fourfold increase in sensitivity when the mass filtering DC or duty cycle was delayed.     

Thin Films that Consist of CuO Mesocrystal Nanosheets: An Application of Microbial‐Mineralization‐Inspired Approaches to Thin‐Film Formation

Thin films of copper oxides can be synthesized on substrates by using approaches that are inspired by microbial mineralization processes. In nature, precipitates of manganese and iron oxides with controlled oxidation states and crystal phases are produced through biomineralization by microorganisms. We have previously reported microbial‐mineralization‐inspired approaches that are comprised of direct and intermediate routes for the controlled syntheses of transition‐metal oxides. Herein, these approaches are applied to the thin‐film formation and coating of copper oxides and a related compound with controlled crystal phases and morphologies. Thin films of CuO, Cu₂O, and Cu₂(OH)₃Cl were selectively synthesized by using direct or intermediate routes. Notably, CuO mesocrystal nanosheets formed a thin film over the whole of the substrate. The resultant CuO mesocrystal nanosheets showed enhanced properties for the electrochemical detection of dopamine. This study shows the potential applicability of microbial‐mineralization‐inspired approaches to thin‐film coatings.     

Green Synthesis of Oxoquinoline-1(2H)-Carboxamide as Antiproliferative and Antioxidant Agents: An Experimental and In-Silico Approach to High Altitude Related Disorders

At high altitudes, drops in oxygen concentration result in the creation of reactive oxygen and nitrogen species (RONS), which cause a variety of health concerns. We addressed these health concerns and reported the synthesis, characterization, and biological activities of a series of 10 oxoquinolines. N-Aryl-7-hydroxy-4-methyl-2-oxoquinoline-1(2H)carboxamides (5a–j) were accessed in two steps under ultrasonicated irradiation, as per the reported method. The anticancer activity was tested at 10 µM against a total of 5 dozen cancer cell lines obtained from nine distinct panels, as per the National Cancer Institute (NCI US) protocol. The compounds 5a (TK-10 (renal cancer); %GI = 82.90) and 5j (CCRF-CEM (Leukemia); %GI = 58.61) showed the most promising anticancer activity. Compound 5a also demonstrated promising DPPH free radical scavenging activity with an IC₅₀ value of 14.16 ± 0.42 µM. The epidermal growth factor receptor (EGFR) and carbonic anhydrase (CA), two prospective cancer inhibitor targets, were used in the molecular docking studies. Molecular docking studies of ligand 5a (docking score = −8.839) against the active site of EGFR revealed two H-bond interactions with the residues Asp855 and Thr854, whereas ligand 5a (docking = −5.337) interacted with three H-bond with the residues Gln92, Gln67, and Thr200 against the active site CA. The reported compounds exhibited significant anticancer and antioxidant activities, as well as displayed significant inhibition against cancer targets, EGFR and CA, in the molecular docking studies. The current discovery may aid in the development of novel compounds for the treatment of cancer and oxidative stress, and other high altitude-related disorders.     

去除粗盐可溶性杂质必须第一步去除硫酸根离子——从盐效应角度分析实验步骤

去除粗盐中可溶性杂质的原理是教学中的一个重点,而实验步骤则是教学中的重中之重.中学教学中通常认为氢氧化钠溶液与氯化钡溶液的添加顺序对实验没有影响,但是由于盐效应,经计算可知添加顺序直接影响硫酸根离子是否能够除净,因此该实验的操作步骤必须第一步去除硫酸根离子,否则硫酸根离子将无法除净.     

Facile Access to Fluoroaromatic Molecules by Transition‐Metal‐Free C–F Bond Cleavage of Polyfluoroarenes: An Efficient,Green, and Sustainable Protocol

The creation of new bonds via C–F bond cleavage of polyfluoroarenes has proven to be an important and powerful tool in synthetic chemistry. Using such a strategy, a myriad of valuable partially fluoroaromatic molecules and building blocks can be obtained. The transition‐metal‐free nucleophilic aromatic substitution (S_NAr) strategy has aroused the continuing interest of researchers due to its simple, mild, economical, and environmentally benign characteristics, which have been successfully applied to C–F bond functionalizations. In this account, we present a summary of the recent investigations of polyfluoroarenes involving S_NAr reactions and discuss some of our recent endeavors in the construction of partially fluoroaromatic molecules. Through this strategy, many new bonds including C–C, C–N, C–O, C–S, and C–H bonds can be created. Additionally, brief discussions on the transformation mechanisms are also provided. Finally, we discuss the existing limitations of the S_NAr reactions of polyfluoroarenes as well as our perspective on the future development of this chemistry.