Hydrogen Nuclear Magnetic Resonance Research Articles

Eco-Friendly Cellulose-Based Nonionic Antimicrobial Polymers with Excellent Biocompatibility, Nonleachability, and Polymer Miscibility.

This study aims to prepare natural biomass-based nonionic antimicrobial polymers with excellent biocompatibility, nonleachability, antimicrobial activity, and polymer miscibility. Two new cellulose-based nonionic antimicrobial polymers (MIPA and MICA) containing many terminal indole groups were synthesized using a sustainable one-pot method. The structures and properties of the nonionic antimicrobial polymers were characterized using nuclear magnetic resonance hydrogen spectroscopy (1H NMR), infrared spectroscopy (FTIR), wide-angle X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), gel chromatography (GPC), and other analytical techniques. The results showed that microcrystalline cellulose (MCC) molecules combined with indole derivatives through an esterification reaction to produce MICA and MIPA. The crystallinity of the prepared MICA and MIPA molecules decreased after MCC modification; their morphological structure changed from short fibrous to granular and showed better thermal stability and solubility. The paper diffusion method showed that both nonionic polymers had good bactericidal effects against the two common pathogenic bacteria Escherichia coli (E. coli, inhibition zone diameters >22 mm) and Staphylococcus aureus (S. aureus, inhibition zone diameters >38 mm). Moreover, MICA and MIPA showed good miscibility with biodegradable poly(vinyl alcohol) (PVA), and the miscible cellulose-based composite films (PVA-MICA and PVA-MIPA) showed good phase compatibility, light transmission, thermal stability (maximum thermal decomposition temperature >300 °C), biocompatibility, biological cell activity (no cytotoxicity), nonleachability, antimicrobial activity, and mechanical properties (maximum fracture elongation at >390%).

Design, Synthesis, and Molecular Docking Studies of 1,3,4-Oxadiazole Scaffolds as Potential Antimicrobial Agents

In search of suitable antimicrobial compounds, we report here the synthesis, characterization, and biological activities of 2-((5-(2-nitrophenyl)-1,3,4-oxadiazol-2-yl)thio)-N-arylacetamide (5a-5p). The molecules were characterized by infrared, mass, hydrogen-1 nuclear magnetic resonance (1H NMR), 13C NMR, and elemental analysis. The in vitro antimicrobial activity was investigated against pathogenic Gram-positive and Gram-negative bacterial and fungal strains. The results were explained with a molecular docking study against microbial DNA gyrase. It was found that the compounds 5h, 5i, 5j, 5k, 5l, 5n, and 5p showed significant activities against tested organisms as compared to standard drugs (fluconazole and ciprofloxacin).

Synthesis and properties of a nonionic water-based epoxy curing agent

Owing to the requirement for environmental protection, water-based coatings have become a significant trend in the development of coatings. The water-based epoxy curing agent has also become a hot research topic. In this study, a B-A-B epoxy compound with a long hydrophobic alkyl chain connected to the intermediate nitrogen atom was synthesized at both ends of a molecule using ethylene glycol diglycidyl ether and 3,4-dimethoxyaniline as raw materials. Subsequently, the epoxy compound was sealed with triethylenetetramine. A nonionic, water-based epoxy resin curing agent with amino groups at both ends of the molecule was prepared. The target product structure was confirmed by infrared spectroscopy (IR), Mass spectrum (MS), and Nuclear magnetic resonance hydrogen spectroscopy (1H-NMR). Additionally, through three factors and three levels of orthogonal experimental design, the optimum experimental conditions were confirmed, the optimum yield was 82.83%. The thermogravimetric analysis (TGA) indicated that the monomer exhibited a significant weight loss in the temperature range of 320–450°C. The pencil hardness, flexibility, and impact resistance of the waterborne epoxy resin coating film prepared by the non-ionic water-based epoxy curing agent reached or exceeded those of similar products at China and foreign countries.

Investigation of cross-scale characterization of porous structure and fluid index in bituminous coal via microwave-LN2 freeze-thaw cycles

Microwave-LN2 cyclic processing (MLCP) is a clean and high-efficiency anhydrous fracturing technology. The change in the porous structure of coal after freeze-thaw cycles significantly affects development efficiency of coalbed methane (CBM) in low porosity and permeability reservoirs, while there is a lack of in-depth macro-meso-micro studies. The damage mechanism of coal under microwave-LN2 cold and thermal shock and the evolution of pore fluid reservoir space is based on cross-scale pore characterisation. This paper evaluates the multi-scale porous structure variations of coal before and after MLCP was assessed by hydrogen nuclear magnetic resonance (1H NNR) and field emission scanning electron microscopy (FE-SEM). The evolutionary trends in coal pore fluid fugacity space under freeze-thaw cycles was indirectly characterised by T1-T2 spectra. Additionally, utilizing T2 distribution, peak area and pore throat changes reflect the evolution trend of coal pore space. The results indicate that as the cycles increased, the coal free water and total fluid reservoir space gradually expanded beyond the cycle threshold (n > 10), the free-fluid index rose to 25.68 %, and the free fluid saturation increased by 20.39 %. Additionally, the NMR permeability of the coal increased by 98.37–1471.65 %, and the pore throat distribution increased by 28.05 %. Comprehensive analysis showed that as the cycles progressed, the free water space in the pore space increased significantly, the proportion of bound water gradually decreased, and the internal pores and fluid space of the coal were improved. This study provides fundamental support for multidimensional evaluation of the porous structure of microwave-LN2 freeze-thaw cycles.

Vortex-assisted microextraction of melamine from milk samples using green short chain ionic liquid solvents coupled with high performance liquid chromatography determination

Melamine is added illegally to milk and dairy products to increase the amount of apparent protein. This organic nitrogen rich chemical compound has been of great challenge in food safety based on its adverse effect on health. Therefore, the extraction and determination of melamine from milk is necessary. Recently, ionic liquid (ILs) as solvent usage has been noticeable for low melting point, low toxicity, high thermal stability, and high extraction capabilities in a wide range of separation processes. ILs are introduced as organic–inorganic salts and green solvents in microextraction preparation. Therefore, in this study, three ionic liquids ([C6mim][NTF2], [C4mim][NTF2] and [C2mim][NTF2] ILs) were prepared and employed as an extraction solvent in dispersive liquid–liquid microextraction (DLLME) of melamine from milk samples followed by HPLC-UV. The selected ILs were designed using three types of alkyl-imidazolium (as the short organic cations) and bis (tri fluoro methyl sulfonyl) imide as anion and characterized by ATR-FTIR spectra, carbon, and hydrogen Nuclear Magnetic Resonance spectroscopy (H&C-NMR) and energy-dispersive X-ray spectroscopy (EDX). These techniques confirmed the formation of functional groups, the structure of hydrogen and carbon atoms, and various elements of ionic bond between imidazolium and bis (tri fluoro methyl sulfonyl) imide. In the next step, the effect of significant parameters, including type and volume of ILs, adsorption time, pH of the sample solution, and sample volume, were optimized. Under the optimal conditions, the limits of detection (LOD), limits of quantification (LOQ), and linearity range were obtained 63.64 µg kg−1, 210.03 µg kg−1, and 210.03–1000 µg kg−1, respectively, for as prepared [C6mim][NTF2] as the best ILs. Notably, the achieved LOQ was lower than the maximum residue level (MRL) for the melamine residue in dairy products. Eventually, the proposed method was applied to detect melamine in milk samples, and the relative recoveries were examined as 79.6–105.0 %.

The Performance and Synthesis of Alkynyl-Functionalized Benzoxazine Containing Phthalide Side Groups and Cyano Groups with Different Molecular Weights.

Benzoxazine resins are widely employed in a variety of applications due to their exceptional heat resistance and treatment properties. However, traditional benzoxazine resins still confront hurdles in today's engineering applications, such as their inability to provide long-term service in high-temperature settings and their inadequate toughness. In this study, four alkyne-functionalized benzoxazines with phthalide side groups and cyano groups of varying molecular weights were produced. Fourier transform infrared spectroscopy (FT-IR) and hydrogen nuclear magnetic resonance spectroscopy (1H-NMR) were used to characterize the resin structure, and differential scanning calorimetry (DSC) was used to investigate the thermal curing kinetics at different warming rates. The apparent activation energy was 116.9 kJ/mol. In-situ FT-IR was used to investigate the cure mechanism. Dynamic mechanical analysis (DMA) was used to evaluate the gelation time of BOZ series resins at various temperatures, and the curing process was designed by combining the results with DSC. The Tg of the composites made using BOZ-1N21 as the matrix was 336 °C, which was much higher than the Tg of the BP-a resin made with aniline, phenolphthalein, and formaldehyde (Tg = 251 °C). As a result, the resin system is expected to be employed in applications requiring high-temperature resistance and toughness.

Synthesis and demulsification mechanism of an ionic liquid with four hydrophobic branches and four ionic centers

Stable emulsions can have numerous negative impacts on both the oil industry and the environment. This study focuses on the synthesis of two ionic liquids (via. PPBD and PPBH) with four hydrophobic branches and four ionic centers that can effectively treat oil-water emulsions at a low temperature of 40 °C. Their chemical structure was explored using Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectra (1H NMR). The effect of temperature, PPBD and PPBH concentration, oil-water ratio, salinity and pH value on the demulsification efficiency (DE) of W/O emulsion was studied detailly and several commercial demulsifiers were also used for comparison. Results revealed that by adding 250 mg/L of PPBH in an E30 emulsion and leaving it for 120 min at 40 °C, the DE could reach 96.34%. Meanwhile, in an E30 emulsion (oil-water mass ratio of 3:7) with 250 mg/L of PPBD, the DE of 95.23% could be obtained at 40 °C for 360 min. Especially, the DE of PPBH could reach 100% in an E70 emulsion (oil-water mass ratio of 7:3) at the same conditions. Additionally, the demulsifier (PPBH) exhibited excellent salt resistance and outperformed some commonly used commercial demulsifiers. Several methods were utilized to investigate the potential demulsification mechanism, including measuring interfacial tension (IFT), three-phase contact angle (CA), droplet contact time, zeta potential, and observing samples under optical microscopy.

Xanthohumol hinders invasion and cell cycle progression in cancer cells through targeting MMP2, MMP9, FAK and P53 genes in three-dimensional breast and lung cancer cells culture

BackgroundDespite recent advances in the treatment of lung and breast cancer, the mortality with these two types of cancer is high. Xanthohumol (XN) is known as a bioactive compound that shows an anticancer effect on cancer cells. Here, we intended to investigate the anticancer effects of XN on the breast and lung cancer cell lines, using the three-dimensional (3D) cell culture.MethodsXN was isolated from Humulus lupulus using Preparative-Thin Layer Chromatography (P-TLC) method and its authenticity was documented through Fourier Transform Infrared spectroscopy (FT-IR) and Hydrogen Nuclear Magnetic Resonance (H-NMR) methods. The spheroids of the breast (MCF-7) and lung (A549) cancer cell lines were prepared by the Hanging Drop (HD) method. Subsequently, the IC50s of XN were determined using the MTT assay in 2D and 3D cultures. Apoptosis was evaluated by Annexin V/PI flow cytometry and NFκB1/2, BAX, BCL2, and SURVIVIN expressions. Cell cycle progression was determined by P21, and P53 expressions as well as PI flow cytometry assays. Multidrug resistance was investigated through examining the expression of MDR1 and ABCG2. The invasion was examined by MMP2, MMP9, and FAK expression and F-actin labeling with Phalloidin-iFluor.ResultsWhile the IC50s for the XN treatment were 1.9 µM and 4.74 µM in 2D cultures, these values were 12.37 µM and 31.17 µM in 3D cultures of MCF-7 and A549 cells, respectively. XN induced apoptosis in MCF-7 and A549 cell lines. Furthermore, XN treatment reduced cell cycle progression, multidrug resistance, and invasion at the molecular and/or cellular levels.ConclusionsAccording to our results of XN treatment in 3D conditions, this bioactive compound can be introduced as an adjuvant anti-cancer agent for breast and lung cancer.

Paenibacillus polymyxa YLC1: A promising antagonistic strain for biocontrol of Pseudomonas syringae pv. actinidiae, causing kiwifruit bacterial canker.

Kiwifruit bacterial canker (KBC) caused by Pseudomonas syringae pv. actinidiae (Psa) is the main limiting factor in the kiwifruit industry. This study aimed to identify bacterial strains with antagonistic activity against Psa, analyze antagonistically active substances, and provide a new basis for the biological control of KBC. A total of 142 microorganisms were isolated from the rhizosphere soil of asymptomatic kiwifruit. Among them, an antagonistic bacterial strain was identified as Paenibacillus polymyxa YLC1 by 16S rRNA sequencing. KBC control by strain YLC1 (85.4%) was comparable to copper hydroxide treatment (81.8%) under laboratory conditions and field testing. Active substances of strain YLC1 were identified by genetic sequence analysis using antiSMASH. The six biosynthetic active compound gene clusters that were identified as encoding ester peptide synthesis, such as polymyxins. An active fraction was purified and identified as polymyxin B1 using chromatography, hydrogen nuclear magnetic resonance (NMR), and liquid chromatography-mass spectrometry. In addition, polymyxin B1 was also found significantly to suppressed the expression of T3SS-related genes but did not affect the growth of Psa at low concentrations. In this study, a biocontrol strain P. polymyxa YLC1 obtained from kiwifruit rhizosphere soil exhibited excellent control effects on KBC in vitro and in field tests. Its active compound was identified as polymyxin B1, which inhibits a variety of pathogenic bacteria. We conclude that P. polymyxa YLC1 is a biocontrol strain with excellent prospects for development and application. This article is protected by copyright. All rights reserved.

Preparation of GO/Cys-Cu(II) as a novel, effective and recoverable catalyst for the multi component synthesis of spirooxindoles under mild conditions

Modified graphene oxide (GO/CPTES/Cys-Cu(II)) was prepared as a reusable catalyst and characterized by various analytical and spectroscopic methods, including Fourier transform spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and inductively coupled plasma (ICP) techniques. Obtained results from demonstrated the existence of cystein/Cu(II) on the MWCNTs surfaces. EDX and ICP analysis shown about 11% Cu (II) and about 8.5% of N element in the catalyst structure. Also, other characterization data confirmed the successfully preparation of synthesized catalyst. The efficiency of this novel catalyst was evaluated through the green synthesis of two variety of spirooxindole derivatives in a One-pot multi component reaction in ethanol as a green solvent. The catalyst showed high efficiency in this process and all of spirooxindoles were obtained after short time (18 min) in high to excellent yields (89–95%). The structure of all obtained products was assigned with hydrogen and carbon nuclear magnetic resonance (1H and 13C NMR) and FTIR. Furthermore, the catalyst could be easily recovered and directly reused at least five times without a notable reduction in activity. The other advantages of the presented methodology are high yields of products without the formation of by-products, simple and clean process, mild reaction conditions and agreement with green chemistry protocols.

Aggregation of ionic liquids with organic anions, driven by cation–anion interaction strength

The properties of ionic liquids (ILs) are related to the structure of their ions, which determines the nature of the cation–anion interaction. However, the direct effect that the structure has on properties such as aggregation and surface activity is not precise, especially when involving dicationic ILs with organic anions. In this study, the aggregation behaviour of imidazolium-based dicationic (1,8-bis(3-methylimidazolium-1-yl)octane - [C8(MIM)2]) ILs containing ibuprofenate [Ibu] and ascorbate [Asc] were evaluated (using conductivity and surface tension) and this was related to the cation–anion interaction strength determined using hydrogen nuclear magnetic resonance and surface plasmon resonance. The results showed that both ILs had a critical aggregation concentration value that was quite low compared to the analogue with a bromide anion. The [C8(MIM)2][2Asc] IL, which has the less hydrophobic anion and has more polar sites, had a greater cation–anion interaction strength and a lower critical aggregation concentration than the [C8(MIM)2][2Ibu] analogue. The cation–anion strength reflected the aggregation properties; for example, [C8(MIM)2][2Asc] had thermodynamically favoured aggregation and better packing of IL monomers at the air–water interface. These results are considered to be relevant for future studies related to the transport and drug loading associated with the use of these ILs.

Quaternary ammonium-functionalized crosslinked poly(aryl ether sulfone)s anion exchange membranes with enhanced alkaline stability for water electrolysis

Quaternary ammonium-functionalized anion exchange membranes (AEMs) have important potential application value in water electrolysis. In order to further improve the ionic conductivity and stability of AEMs, a series of crosslinked AEMs based on poly (aryl ether sulfone)s (Co-PAES-QA-x-m, “x” represents the functionalized polymer segment, “m” represents the crosslinking ratio) are prepared by introducing dense quaternary ammonium cations on the side chains via Menshutkin reaction. Their polymer structures are characterized by hydrogen nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy FT-IR, and the microscopic phase separation structure of the obtained membranes is observed by atomic force microscope AFM. The ion exchange capacity (IEC) of Co-PAES-QA-x-m (x = 25%, m = 40%–100%) is between 2.03–2.48 mmol g−1, and their water uptake (WU), swelling ratio (SR) and ionic conductivity are in the range of 26.9–56.7%, 6.3–12.9% and 53.43–119.43 mS cm−1 at 80 °C, respectively. The test of chemical stability show that the ionic conductivity retention ratio of these AEMs reaches 84.7% after soaking in 2 mol L−1 NaOH solution for 480 h at 80 °C. The water electrolyzer assembled with representative Co-PAES-QA-25-60 reaches 1646.7 mA cm−2 in 2 mol L−1 NaOH solution at 2.0 V and 80 °C, and the durability test shows that its voltage only rises by 5% after 480 h at the current density of 500 mA cm−2. This work is expected to provide an effective modification method for high-performance AEMs which are used in water electrolyzer.

Study on Synthesis and Performance of Methyl Diphenyl Urea Stabilizer

Diphenylamine (DPA), formyl chloride, and sodium hydride (NaH) as raw materials synthesize methyldiphenylurea stabilizer by alkylation reaction. The physical and chemical properties of methyldiphenylurea were characterized by nuclear magnetic resonance hydrogen spectrum (1HNMR), X-ray energy spectrum (EDS), Fourier transforms infrared spectroscopy (FT-IR) and differential thermal analysis (DTA). Thermal Decomposition Experiment of Nitrate Propellant Containing Stabilizer by Thermogravimetric Analysis (TGA), exploring the Effect of Different Stabilizers. The molecular surface electrostatic potential energy of methyl diphenyl urea, triphenylamine ( TPA ), dimethyl diphenyl urea (C2), and glycerol trinitrate were calculated by Materials Studio software. The interaction between the stabilizer and glycerol trinitrate molecule was studied. The results showed that the weight loss rate of methyl diphenyl urea was less than 0.1 % within 30 days, and the chemical stability was good. And its negative electrostatic potential energy is larger than that of C2 and TPA, its intermolecular binding ability with glycerol trinitrate is stronger, and its inhibition of nitrate decomposition stability is the best.

Preparation of pH/Light dual-responsive biocompatible polymer micelles: Application to curcumin delivery

Polymer micelles play an important role in the research of drug delivery system because of their nano-size, unique “core-shell” structure and surface modifiability. A pH/photosensitive drug carrier, PEG-PDMAEMA-PNBAE, was synthesized by atom transfer radical polymerization (ATRP) using hydrophilic poly (N, N dimethylaminoethyl methacrylate) (PDMAEMA) as the pH-responsive chain segment and hydrophobic poly (o-nitrobenzyl acrylate) (PNBAE) as the light-responsive chain segment. The molecular and structural characteristics of the polymer were spectroscopically characterized with Fourier transform infrared spectrometer (FT-IR), Nuclear magnetic resonance hydrogen spectrum (1H NMR) and Gel permeation chromatography column (GPC). The morphology and size of micelles were observed by Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The stability of micelles was detected by Laser particle size analyzer (DLS). The Critical micelle concentration (CMC) of the polymer was analyzed by Fluorescence spectrophotometer (Flu), and the photosensitivity of the micelles was determined by Ultraviolet–visible spectrophotometer (UV). The results showed that the synthesized polymers could self-assemble into homogeneous and stable spherical micelles and their particle size was about 100 nm with effective light sensitivity. Curcumin (Cur) was used as a model drug to investigate the adsorption and release abilities of the micelles. The adsorption performance test of the polymeric micelles showed an encapsulation rate of 77.82% and a drug loading capacity of 13.46%. In vitro drug release results showed cumulative drug release rates of 31.79% and 46.55% at pH 5.5 and pH 5.5+UV, indicating the dual pH and light responsiveness of the synthesized carrier. The in vitro hemolysis and cytotoxicity test demonstrated that the carrier has good biosafety.

Synthesis and properties of a new polycarboxylic acid multi‐polymer scale inhibitor suitable for industrial circulating water

AbstractMultipolymer TPEG‐IA‐AMPS was synthesized by free‐radical polymerization using isopentenol polyoxyethylene ether (TPEG), itaconic acid (IA) and 2‐acrylamide‐2‐methylpropanesulfonic acid (AMPS) as monomers. In addition, the monomers and the synthesized multipolymer were characterized and analyzed by infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (1H‐NMR) and gel permeation chromatography (GPC). And then, the control variable method and static scale inhibition method were used to measure the influence of different synthesis conditions on the calcium carbonate scale inhibition performance of multipolymer, and the optimum synthesis conditions of terpolymer were determined. Meanwhile, the influence of different factors on the scale inhibition performance of calcium carbonate scale and calcium sulfate scale under the optimum synthesis conditions was also explored. Moreover, scanning electron microscope (SEM) and x‐ray diffraction (XRD) were used to analyze the scale inhibition mechanism. The results show that the synthesized multipolymer TPEG‐IA‐AMPS is suitable for industrial recycling wastewater in harsh environment such as high alkalinity, high hardness and high PH.

Effect of chain transfer agents in polycarboxylate superplasticizer on slump‐retention of concrete

AbstractTwo types of slump‐retention polycarboxylate superplasticizers (PC‐M and PC‐S) were synthesized by using 3‐mercaptopropionic acid or sodium hypophosphite as chain transfer agents, the effects of polycarboxylate superplasticizers on slump‐retention of cement and concrete were investigated, and the mechanism of action and the structure of polycarboxylate superplasticizers were investigated by using conductivity, complexing Ca2+ concentration, gel permeation chromatography (GPC), nuclear magnetic resonance hydrogen spectroscopy (1H‐NMR), and nuclear magnetic resonance phosphorus spectroscopy (31P‐NMR). The results indicated that the slump flow of cement paste mixed with PC‐M was increased quickly within 60 min and then lost gradually, while PC‐S increased slowly and evenly within 240 min. The slump flow of concrete mixed with PC‐S reached 405 mm after 150 min, but the concrete mixed with PC‐M was almost no fluidity after 150 min. The conductivity of the PC‐M aqueous solution decreased quickly within 45 min, then slowly decreased, while the conductivity of the PC‐S aqueous solution decreased slowly within 180 min. PC‐M had a much greater complexation ability of Ca2+ than PC‐S. The composition and structure of the two slump‐retention polycarboxylate superplasticizers were altered by different chain transfer agents, and the hydrolysis‐adsorption capacity of each component was different. The rate of hydrolyzation‐adsorption of each component was PC‐M3 ≈ PC‐S3>PC‐M1>PC‐M2 ≈ PC‐S1>PC‐S2. The faster the adsorption rate, the faster the slump flow loss of concrete.

Synthesis of epoxidized natural rubber grafted with hyaluronic acid for the development of biomaterials

Natural Rubber (NR), extracted from Hevea brasiliensis rubber trees, is a biocompatible biopolymer with properties that support in the tissue repair process. However, its biomedical applications are limited due to the presence of allergenic proteins, hydrophobicity, and unsaturated bonds. To overcome these limitations and contribute to the development of new biomaterials, this study aims to deproteinize, epoxidize, and subject NR to copolymerization by grafting with hyaluronic acid (HA), which is widely recognized for its bioactive properties in the medical field. The deproteinization, epoxidation, and graft copolymerization through the esterification reaction were confirmed by Fourier Transform Infrared Spectroscopy and Hydrogen Nuclear Magnetic Resonance Spectroscopy analysis. Thermogravimetry and Differential Scanning Calorimetry demonstrated that the grafted sample exhibited a lower degradation rate and a higher glass transition temperature, indicating strong intermolecular interactions. Moreover, contact angle measurement revealed that the grafted NR exhibited a high hydrophilic character. The results obtained suggest the formation of a novel material with great potential for application in biomaterials involved in tissue repair processes.

Synthesis of a high efficiency DED-12 demulsifier by a simple two-step method

In this paper, a high efficiency DED-12 demulsifier was synthesized using poly (ethylene glycol) diglycidyl ether and ethanolamine as raw materials through a simple two-step method. The DED-12 structure was assessed using both Fourier transform infrared spectrometer and nuclear magnetic resonance hydrogen spectra. Additionally, demulsifying performance of DED-12 was evaluated by bottle test and the effect of concentration, pH value, salinity and temperature on the demulsification efficiency (DE) was studied in detail. The results showed that the DE reached 92.9 % in an emulsion with 70 % water content at 50 ℃ when 300 mg/L of DED-12 was used for 180 min. Especially, it reached 100 % in an emulsion with 30 % water content at 60 ℃. Moreover, DED-12 had good tolerance of acid, alkali and salt. The interfacial competitive adsorption and demulsification mechanism was investigated by the interfacial tension (IFT), three-phase contact angle (CA), zeta potential, coalescence time of droplets (CTD) and optical microscopic observation.

Spiral Square Nanosheets Assembled from Ru Clusters.

Spiral two-dimensional (2D) nanosheets exhibit unique physical and chemical phenomena due to their twisted structures. While self-assembly of clusters is an ideal strategy to form hierarchical 2D structures, it is challenging to form spiral nanosheets. Herein, we first report a screw dislocation involved assembled method to obtain 2D spiral cluster assembled nanosheets (CANs) with uniform square morphology. The 2D spiral Ru CANs with a length of approximately 4 μm and thickness of 20.7 ± 3.0 nm per layer were prepared via the assembly of 1-2 nm Ru clusters in the presence of molten block copolymer Pluronic F127. Cryo-electron microscopy (cryo-EM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) demonstrate the existence of screw dislocation in the spiral assembled structure. The X-ray absorption fine structure spectrum indicates that Ru clusters are Ru3+ species, and Ru atoms are mainly coordinated with Cl with a coordination number of 6.5. Fourier-transform infrared (FT-IR) spectra and solid-state nuclear magnetic resonance hydrogen spectra (1H NMR) indicate that the assembly process of Ru clusters is formed by noncovalent interactions, including hydrogen bonding and hydrophilic interactions. Additionally, the Ru-F127 CANs exhibit excellent photothermal conversion performance in the near-infrared (NIR) region.

Synthesis of near infrared absorbing cationic zinc aminophthalocyanine and its application as an efficient photo-sensitizing nanoparticle in anti-drug-resistant bacteria

The emergence of drug-resistant bacteria threatens human health, and photodynamic therapy and photothermal therapy are promising methods to eliminate drug-resistant bacteria. However, the key to photodynamic and photothermal therapy is efficient photosensitizers, which are not fully developed. Herein, a novel cationic zinc aminophthalocyanine, zinc tetrakis(dimethyloctylammonium bromide) phthalocyanine (DMAZnPc-C8), is synthesized and investigated. The structures of the cationic zinc aminophthalocyanines are characterized by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance hydrogen spectrum (1H NMR)，Mass spectrometry and X-ray spectroscopy. The singlet oxygen generation ability, photo-thermal properties and antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) of cationic zinc aminophthalocyanine nanoparticles (DMAZnPc-C8 NP) in aqueous dispersion are investigated. The results show that the maximum ultraviolet absorption wavelength of DMAZnPc-C8 in DMSO is at 764 nm, and DMAZnPc-C8 shows good response to near-infrared light. DMAZnPc-C8 NP has good photo-thermal performance. After irradiation with an 808 nm laser (0.5 W/cm2) for 10 min, the temperature of DMAZnPc-C8 NP dispersion (0.05 mg/mL) is increased by 7.4 °C. And DMAZnPc-C8 NP has good singlet oxygen production capacity. DMAZnPc-C8 NP has excellent antibacterial effect against MRSA-resistant bacteria. When the concentration of DMAZnPc-C8 NP is 0.03 mg/mL, the growth of MRSA is almost completely inhibited after 10 min of laser irradiation at 808 nm (0.5 W/cm2), the antibacterial rate reach over 99 %. This study shows that cationic zinc aminophthalocyanine has promising application prospects in the field of anti-drug-resistant bacteria.