Synthesis and characterization of poly(vinyl amine)‐based amphiphilic comb‐like dextran glycopolymers by a two‐step method

Poly(vinyl amine) (PVAm)‐based amphiphilic glycopolymers were synthesized by a two‐step method, that is dextran molecules (Dex, M_w = 1500) were attached to the PVAm backbone by reacting amine groups with dextran lactone, and then, hexanoyl groups (Hex) were attached by reacting the PVAm free amine groups with N‐(hexanoyloxy)succinimide. By adjustment of the feed ratios of Dex/Hex, amphiphilic comb‐like glycopolymers with various hydrophilic and hydrophobic balances were prepared, and their structures were characterized by ¹H NMR. Surface activity of the amphiphilic glycopolymers at the air/water interface was demonstrated by reduction in water surface tension. Adsorption of the amphiphilic glycopolymers at the solid/water interface was examined on octadecyltrichlorosilane (OTS)‐coated coverslips by water contact angle measurements. The results show that the amphiphilic glycopolymers need about 20 mol % of dextran attachment to make an effective hydrophilic coating. In comparison with the one‐step reaction by addition of dextran lactone and alkyl succinimide simultaneously, the two‐step approach can attach Dex on PVAm as high as possible in the first step, and offers quantitative advantages in controlling the ratio of hydrophilic and hydrophobic chains along the PVAm backbone, resulting in increased water solubility for the final amphiphilic glycopolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 192–199, 2006     

A meta-analysis of tumor necrosis factor (TNF) gene polymorphism and susceptibility to influenza A (H1N1)

PurposeThe aim of the study was to comprehensively evaluate the associations between tumor necrosis factor (TNF) gene polymorphism and influenza A (H1N1) susceptibility.MethodsThe relevant studies were identified through a search of PubMed, Embase, and Cochrane library database until February 29, 2020, without language restrictions. Two independent reviewers extracted the data, and any discrepancies were resolved by consensus. The quality of the eligible article was evaluated by Newcastle-Ottawa Quality Assessment Scale (NOS). Egger’s test was applied to evaluate publication bias. All these analyses were performed using Stata15.1 software.ResultsA total of 5 studies with 474 cases and 805 controls were included. The results of meta-analysis showed that there were statistically significant for rs361525 in allelic model (A vs. G) [OR = 2.46 (1.10, 5.52)] and for rs1800750 in dominant model (AA + GA vs. GG) [OR = 2.42 (1.24, 4.71)] in cases vs. controls. Furthermore, subgroup analysis for race showed that for rs361525 in allelic model (A vs. G), there were significant differences for Caucasian [OR = 3.64 (1.18, 11.23)] and no significant difference for Mexican [OR = 2.25 (0.82, 6.13)] in cases vs. controls. There was publication bias for rs361525 in dominant model (AA + GA vs. GG, p = 0.042) and rs1800629 in recessive model (AA vs. GG + GA, p < 0.001).ConclusionsCaucasian with A site mutation of -238TNF G/A (rs361525) was more susceptible to influenza A (H1N1).The -376 dominant model AA + GA of TNF genes was associated with the susceptibility to influenza A (H1N1). However, more studies with large sample size are needed to confirm the results.     

Biometallization‐Based Electrochemical Magnetoimmunosensing Strategy for Avian Influenza A (H7N9) Virus Particle Detection

A highly sensitive electrochemical immunosensor for avian influenza A (H7N9) virus (H7N9 AIV) detection was proposed by using electrochemical magnetoimmunoassay coupled with biometallization and anodic stripping voltammetry. This strategy could accumulate the enzyme‐generated product on the surface of the magneto electrode by means of silver deposition, which amplified the detection signal about 80 times. The use of magnetic beads (MBs) and the magneto electrode could also amplify the detection signal. Furthermore, a bi‐electrode signal transduction system was introduced into this immunosensor, which is also beneficial to the immunoassay. A concentration as low as 0.011 ng mL^?1 of H7N9 AIV could be detected in about 1.5 h with good specificity. This study not only provides a simple and sensitive approach for virus detection but also offers an effective signal enhancement strategy for the development of highly sensitive MB‐based electrochemical immunoassays.     

A two‐dimensional cadmium(II) polymer based on nicotinic acid and thiocyanate ligands

A cadmium–thiocyanate complex, poly[[bis(nicotinic acid‐κN)di‐μ‐thiocyanato‐κ²N:S;κ²S:N‐cadmium(II)] monohydrate], {[Cd(NCS)₂(C₆H₅NO₂)₂]·H₂O}_n, was synthesized by the reaction of nicotinic acid, cadmium nitrate tetrahydrate and potassium thiocyanide in aqueous solution. In the crystal structure, each Cd^II cation is in a distorted octahedral coordination environment, coordinated by the N and S atoms of nicotinic acid and thiocyanate ligands. Neighbouring Cd^II cations are linked together by thiocyanate bridges to form a two‐dimensional network. Hydrogen‐bond interactions between the uncoordinated solvent water molecules and the organic ligands result in the formation of the three‐dimensional supramolecular network.     

A new two‐dimensional manganese(II) coordination polymer based on thiophene‐3,4‐dicarboxylic acid

A novel manganese coordination polymer, poly[(μ₅‐thiophene‐3,4‐dicarboxylato)manganese(II)], [Mn(C₆H₂O₄S)]_n, was synthesized hydrothermally using 3,4‐thiophenedicarboxylate (3,4‐tdc²⁻) as the organic linker. The asymmetric unit of the complex contains an Mn²⁺ cation and one half of a deprotonated 3,4‐tdc²⁻ anion, both residing on a twofold axis. Each Mn²⁺ centre is six‐coordinated by O atoms of bridging/chelating carboxylate groups from five 3,4‐tdc²⁻ anions, forming a slightly distorted octahedron. The Mn²⁺ centres are bridged by 3,4‐tdc²⁻ anions to give an infinite two‐dimensional layer which incorporates one‐dimensional Mn–O gridlike chains, and in which the 3,4‐tdc²⁻ anion adopts a novel hexadentate chelating and μ₅‐bridging coordination mode. The fully deprotonated 3,4‐tdc²⁻ anion exhibits unexpected efficiency as a ligand towards the Mn²⁺ centres, which it coordinates through all of its carboxylate O atoms to provide the novel coordination mode. The IR spectrum of the complex is also reported.     

Separation and isolation of major polyphenols from maritime pine (Pinus pinaster) knots by two‐step centrifugal partition chromatography monitored by LC‐MS and NMR spectroscopy

Pine knots are a rich source of lignans, flavonoids, and stilbenes. These bioactive compounds are widely known for their roles to combat human disorders but also to protect plants against pathogens. In order to gain knowledge inside their potential activities, a suitable isolation and purification of these high‐added value compounds is required. To this end, centrifugal partition chromatography, as a rapid and useful methodology of separation, was employed and developed. The coefficient partition values (K_D) of six major compounds in nine biphasic solvent systems were determined to evaluate the most appropriate system. Two‐step centrifugal partition chromatography was required to separate lignans using ARIZONA system K (n‐heptane/ethyl acetate/methanol/water 1:2:1:2, v:v) and to isolate stilbenes and flavonoids using ARIZONA system P (n‐heptane/ethyl acetate/methanol/water 6:5:6:5, v:v). Eight one‐compound enriched‐fractions were obtained as follows: nortrachelogenin (70.1%), secoisolariciresinol (53.7%), isolariciresinol (61.1%), taxifolin (48.4%), pinocembrin (91.3%), pinobanksin (91.1%), pinosylvin (91.4%), and pinosylvin monomethyl ether (91.1%). Additionally, the centrifugal partition chromatography allowed to unravel the composition of pine knot owing to the several fractions generated. Twenty‐two compounds were characterized by liquid chromatography‐mass spectrometry and NMR spectroscopy, some of which are described for the first time in literature.     

A lvt‐type Framework [Cu2(tza)4]·ClO4·4H2O Derived from 1H‐tetrazole‐1‐acetic Acid

The reaction of 1H‐tetrazole‐1‐acetic acid (Htza) and perchloric acid with cuprous chloride with slow evaporation at room temperature gave a novel 3D porous Cu^II coordination polymer, [Cu₂(tza)₄] · ClO₄ · 4H₂O ( 1 ), (tza = tetrazole‐1‐acetate). The structure exhibits an unusual 3D microporous coordination framework built up by four coordinated Cu^II nodes and bidentate bridging tza ligands with lvt‐type topology. Furthermore, the magnetic properties of complex 1 were also investigated.     

Synthesis and characteristics of poly(methacrylic acid‐co‐N‐isopropylacrylamide) thermosensitive composite hollow latex particles and their application as drug carriers

In this work, the poly(methacrylic acid‐co‐N‐isopropylacrylamide) thermosensitive composite hollow latex particles was synthesized by a three‐step reaction. The first step was to synthesize the poly(methyl methacrylate‐co‐methacrylic acid) (poly(MMA‐MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second step was to polymerize methacrylic acid (MAA), N‐isopropylacrylamide (NIPAAm), and N,N′‐methylenebisacrylamide in the presence of poly(MMA‐MAA) latex particles to form the linear poly(methyl methacrylate‐co‐methacrylic acid)/crosslinking poly(methacrylic acid‐co‐N‐isopropylacrylamide) (poly(MMA‐MAA)/poly(MAA‐NIPAAm)) core–shell latex particles. In the third step, the core–shell latex particles were heated in the presence of ammonia solution to form the crosslinking poly(MAA‐NIPAAm) thermosensitive hollow latex particles. The morphologies of poly(MMA‐MAA)/poly(MAA‐NIPAAm) core–shell latex particles and poly(MAA‐NIPAAm) hollow latex particles were observed. The influences of crosslinking agent and shell composition on the lower critical solution temperature of poly(MMA‐MAA)/poly(MAA‐NIPAAm) core–shell latex particles and poly(MAA‐NIPAAm) hollow latex particles were, respectively, studied. Besides, the poly(MAA‐NIPAAm) thermosensitive hollow latex particles were used as carriers to load with the model drug, caffeine. The effect of various variables on the amount of caffeine loading and the efficiency of caffeine release was investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5203–5214     

A rapid site‐specific PCR based one‐tube authentication method for saffron in crude drugs and processed herbal medicines

Saffron is one of the world's most precious medicinal herbs and often found to be adulterated with other cheaper materials. The chemical compounds in Crocus sativus L. such as crocin, picrocrocin also exist in other plants, which makes the chemotype‐driven analysis not ideal for the quality control of saffron. Herein, we developed a rapid authentication method for saffron in crude drugs by the site‐specific PCR. In order to realize fast high‐throughput analysis, a one‐tube identification approach was further established by using a universal fluorescent dye to detect the PCR products. In addition, this method was also applied to the authentication of saffron in a processed herbal medicine “Er shi wu wei shan hu wan” which consists of twenty‐five kinds of medicinal materials including plants, minerals and animals. Additionally, this method was also proved to be with high specificity and repeatability. The flexibility of choosing different primers also made this method versatile for other medicinal materials.     

Synthesis and characteristics of poly(methyl methacrylate‐co‐methacrylic acid)/poly(methacrylic acid‐co‐N‐isopropylacrylamide) thermosensitive semi‐hollow latex particles and their application to drug carriers

In this work, the poly(methyl methacrylate‐co‐methacrylic acid)/poly(methacrylic acid‐co‐N‐isopropylacrylamide) thermosensitive composite semi‐hollow latex particles was synthesized by three processes. The first process was to synthesize the poly(methyl methacrylate‐co‐methacrylic acid) (poly (MMA‐MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second process was to polymerize methacrylic acid (MAA), N‐isopropylacrylamide (NIPAAm), and crosslinking agent, N,N′‐methylenebisacrylamide, in the presence of poly(MMA‐MAA) latex particles to form the linear poly(methyl methacrylate‐co‐methacrylic acid)/crosslinking poly(methacrylic acid‐co‐N‐isopropylacrylamide) (poly(MMA‐MAA)/poly(MAA‐NIPAAm)) core–shell latex particles with solid structure. In the third process, part of the linear poly(MMA‐MAA) core of core–shell latex particles was dissolved by ammonia to form the poly(MMA‐MAA)/poly(MAA‐NIPAAm) thermosensitive semi‐hollow latex particles. The morphologies of the semi‐hollow latex particles show that there is a hollow zone between the linear poly(MMA‐MAA) core and the crosslinked poly(MAA‐NIPAAm) shell. The crosslinking agent and shell composition significantly influenced the lower critical solution temperature of poly(MMA‐MAA)/poly(MAA‐NIPAAm) semi‐hollow latex particles. Besides, the poly(MMA‐MAA)/poly(MAA‐NIPAAm) thermosensitive semi‐hollow latex particles were used as carriers to load with the model drug, caffeine. The processes of caffeine loaded into the semi‐hollow latex particles appeared four situations, which was different from that of solid latex particles. In addition, the phenomenon of caffeine released from the semi‐hollow latex particles was obviously different from that of solid latex particles. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3441–3451     

A two‐dimensional copper(II) coordination polymer based on 2,4′‐oxybis(benzoate) and 4,4′‐bipyridine

The reaction of Cu(NO₃)₂·3H₂O with 2,4′‐oxybis(benzoic acid) and 4,4′‐bipyridine under hydrothermal conditions produced a new mixed‐ligand two‐dimensional copper(II) coordination polymer, namely poly[[(μ‐4,4′‐bipyridine‐κ²N ,N ′)[μ‐2,4′‐oxybis(benzoato)‐κ⁴O ²,O ^2′:O ⁴,O ^4′]copper(II)] monohydrate], {[Cu(C₁₄H₈O₅)(C₁₀H₈N₂)]·H₂O}_n , which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction. The X‐ray diffraction crystal structure analysis reveals that the Cu^II ions are connected to form a two‐dimensional wave‐like network through 4,4′‐bipyridine and 2,4′‐oxybis(benzoate) ligands. The two‐dimensional layers are expanded into a three‐dimensional supramolecular structure through intermolecular O—H…O and C—H…O hydrogen bonds. Furthermore, magnetic susceptibility measurements indicate that the complex shows weak antiferromagnetic interactions between adjacent Cu^II ions.     

A two‐dimensional copper(II) coordination polymer based on 2‐propyl‐1H‐imidazole‐4,5‐dicarboxylic acid

Single‐crystal X‐ray diffraction analysis of poly[bis(μ₂‐5‐carboxy‐2‐propyl‐1H‐imidazole‐4‐carboxylato‐κ³N³,O⁴:O⁵)copper(II)], [Cu(C₈H₉N₂O₄)₂)]_n, indicates that one carboxylic acid group of the 2‐propyl‐1H‐imidazole‐4,5‐dicarboxylic acid (H₃PDI) ligand is deprotonated. The resulting H₂PDI⁻ anion, acting as a bridge, connects the Cu^II cations to form a two‐dimensional (4,4)‐connected layer. Adjacent layers are further linked through interlayer hydrogen‐bond interactions, resulting in a three‐dimensional supramolecular structure.     

A multiplex SNP genotyping by allele‐specificspecific PCR based on stem‐loop and universal fluorescent primers of Chr1daxin mice

Single nucleotide polymorphisms (SNPs) are one of the most common markers in mammals. Rapid, accurate, and multiplex typing of SNPs is critical for subsequent biological and genetic research. In this study, we have developed a novel method for multiplex genotyping SNPs in mice. The method involves allele‐specific PCR amplification of genomic DNA with two stem‐loop primers accompanied by two different universal fluorescent primers. Blue and green fluorescent signals were conveniently detected on a DNA sequencer. We verified four SNPs of 65 mice based on the novel method, and it is well suited for multiplex genotyping as it requires only one reaction per sample in a single tube with multiplex PCR. The use of universal fluorescent primers greatly reduces the cost of designing different fluorescent probes for each SNP. Therefore, this method can be applied to many biological and genetic studies, such as multiple candidate gene testing, genome‐wide association study, pharmacogenetics, and medical diagnostics.     

Amphiphilic conetworks. IV. Poly(methacrylic acid)‐l‐polyisobutylene and poly(acrylic acid)‐l‐polyisobutylene based hydrogels prepared by two‐step polymer procedure. New pH responsive conetworks

This article describes the synthesis and characterization of new amphiphilic polymer conetworks containing hydrophilic poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) and hydrophobic polyisobutylene (PIB) chains. These conetworks were prepared by a two‐step polymer synthesis. In the first step, a cationic copolymer of isobutylene (IB) and 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate (IDI) was prepared. The isocyanate groups of the IB–IDI random copolymer were subsequently transformed in situ to methacrylate (MA) groups in reaction with 2‐hydroxyethyl methacrylate (HEMA). In the second step, the resulting MA‐multifunctional PIB‐based crosslinker, PIB(MA)_n, with an average functionality of approximately four methacrylic groups per chain, was copolymerized with methacrylic acid (MAA) or acrylic acid (AA) by radical mechanism in tetrahydrofuran giving rise to amphiphilic conetworks containing 31–79 mol % of MAA or 26–36 mol % of AA. The synthesized conetworks were characterized with solid‐state ¹³C‐NMR spectroscopy and differential scanning calorimetry. The amphiphilic nature of the conetworks was proven by swelling in both aqueous media with low and high pH and n‐heptane. The effect of varying pH on the swelling behavior of the synthesized conetworks is presented. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1284–1291, 2009     

A New Copper(II) Complex with the N,N′‐Tetra(antipyryl‐4‐methyl)‐1,2‐ethanediamine (TAMEN) Ligand: [Cu(TAMEN)](ClO4)2·H2O·DMF

The synthesis of the Mannich base N,N′‐tetra(antipyryl‐4‐methyl)‐1,2‐ethanediamine (TAMEN) ( 1 ), its crystal structure as well as the synthesis and the crystal structure of the copper complex [Cu(TAMEN)](ClO₄)₂·H₂O·DMF ( 2 ) are reported. C₅₀H₅₆N₁₀O₄·2C₂H₅OH (TAMEN·2EtOH) crystallizes with triclinic symmetry, space group , lattice parameters: a = 877.3(1), b = 1078.1(1), c = 1433.3(2) pm, α = 71.93(1), β = 82.16(1), γ = 84.54(1)° and Z = 1. The copper complex [Cu(TAMEN)](ClO₄)₂·H₂O·DMF also crystallizes with triclinic symmetry, space group , lattice parameters: a = 1279.2(2), b = 1485.6(2), c = 1513.6(2) pm, α = 98.04(1), β = 101.24(1), γ = 94.66(1)° and Z = 2. The copper(II) atom is six‐coordinate with an elongated pseudo‐octahedral geometry due to a strong Jahn‐Teller effect.     

Mechanisms for H2O decomposition on the Si(111)‐7 × 7 surface: A DFT cluster model study

The mechanisms for the complete decomposition of water molecules on the Si (111)‐7 × 7 surface were investigated theoretically. The reaction pathways for dissociation of four water molecules over the adatom and rest atom sites were calculated using the density functional theory (DFT) in conjunction with the B3LYP functional. The calculated results demonstrated that the initial O? H bond dissociation from the first H₂O to form the adsorbed OH species is more preferential on the adatom site (Si_a) than the rest atom site (Si_r) of Si (111)‐7 × 7. Four water molecules dissociate successively over the adatom site, backbonds of adatoms which are saturated by OH species can reasonably be the place of insertion of oxygen atoms, yielding a tetrahedral SiO₄ structure with one on top and three inserted oxygen atoms. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Amphiphilic conetworks. III. Poly(2,3‐dihydroxypropyl methacrylate)–polyisobutylene and poly(ethylene glycol) methacrylate–polyisobutylene based hydrogels prepared by two‐step polymer procedure

This article describes the synthesis and characterization of new amphiphilic polymer conetworks containing hydrophilic poly(2,3‐dihydroxypropyl methacrylate) or poly(ethylene glycol) methacrylate (PEGMA) and hydrophobic polyisobutylene chains. This conetworks were prepared by a two‐step polymer synthesis. In the first step, a cationic copolymer of isobutylene and 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate (IDI) was prepared. The isocyanate groups of the IB‐IDI random copolymer were subsequently transformed in situ to methacrylate (MA) groups in reaction with 2‐hydroxyethyl methacrylate (HEMA). In the second step, the resulting MA‐multifunctional PIB‐based crosslinker, PIB(MA)_n, with an average functionality of approximately four per chain, was copolymerized with 2,3‐dihydroxypropyl methacrylate or poly(ethylene glycol) methacrylate by radical mechanism in tetrahydrofuran giving rise to amphiphilic conetworks containing 11–60 mol % of DHPMA or 10–12 mol % of PEGMA. The synthesized conetworks were characterized with solid‐state ¹³C‐NMR spectroscopy and differential scanning calorimetry. The amphiphilic nature of the conetworks was proved by swelling in both water and n‐heptane. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4074–4081, 2007     

A threefold interpenetrated two‐dimensional zinc(II) supramolecular architecture based on 3‐nitrobenzoic acid and 4,4′‐bipyridine

With regard to crystal engineering, building block or modular assembly methodologies have shown great success in the design and construction of metal–organic coordination polymers. The critical factor for the construction of coordination polymers is the rational choice of the organic building blocks and the metal centre. The reaction of Zn(OAc)₂·2H₂O (OAc is acetate) with 3‐nitrobenzoic acid (HNBA) and 4,4′‐bipyridine (4,4′‐bipy) under hydrothermal conditions produced a two‐dimensional zinc(II) supramolecular architecture, catena‐poly[[bis(3‐nitrobenzoato‐κ²O,O′)zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′], [Zn(C₇H₄NO₄)₂(C₁₀H₈N₂)]_n or [Zn(NBA)₂(4,4′‐bipy)]_n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction analysis. The Zn^II ions are connected by the 4,4′‐bipy ligands to form a one‐dimensional zigzag chain and the chains are decorated with anionic NBA ligands which interact further through aromatic π–π stacking interactions, expanding the structure into a threefold interpenetrated two‐dimensional supramolecular architecture. The solid‐state fluorescence analysis indicates a slight blue shift compared with pure 4,4′‐bipyridine and HNBA.