Search

Quaternary ammonium compounds (QACs) are widely detected in the aquatic environment due to their extensive use in a wide array of antibacterial products during the pandemic. In the current study, UV/monochloramine (UV/NH 2 Cl) was used to degrade three typical QACs, namely benzalkonium compounds (BACs), dialkyl dimethyl ammonium compounds (DADMACs), and alkyl trimethyl ammonium compounds (ATMACs). This process achieved high efficiency in removing BACs from water samples. The transformation products of QACs treated with UV/NH 2 Cl were identified and characterized using a high-resolution mass spectrometer, and transformation pathways were proposed. The formation of N-nitroso-N-methyl-N-alkylamines (NMAs) and N-nitrosodimethylamine (NDMA) were observed during QAC degradation. The molar formation yield of NDMA from C 12 -BAC was 0.04 %, while yields of NMAs reached 1.05 %. The ecotoxicity of NMAs derived from QACs was predicted using ECOSAR software. The increased toxicity could be attributed to the formation of NMAs with longer alkyl chains; these NMAs, exhibited a one order of magnitude increase in toxicity compared to their parent QACs. This study provides evidence that QACs are the specific and significant precursors of NMAs. Greater attention should be given to NMA formation and its potential threat to the ecosystem, including humans. [Display omitted] • Transformation pathways for QACs in UV/NH 2 Cl process are proposed for the first time. • Aliphatic QACs were poorly removed by UV/NH 2 Cl process. • QACs are specific and significant precursors of NMAs. • Molar formation yield of C 12 -NMA from C 12 -BAC was 26 times higher than of NDMA. • NMAs derived from QACs were more toxic than NDMA. [ABSTRACT FROM AUTHOR]

Purpose: Plasma trimethylamine-N-oxide (TMAO) levels have been shown to correlate with increased risk of metabolic diseases including cardiovascular diseases. TMAO exposure predominantly occurs as a consequence of gut microbiota-dependent trimethylamine (TMA) production from dietary substrates including choline, carnitine and betaine, which is then converted to TMAO in the liver. Reducing microbial TMA production is likely to be the most effective and sustainable approach to overcoming TMAO burden in humans. Current models for studying microbial TMA production have numerous weaknesses including the cost and length of human studies, differences in TMA(O) metabolism in animal models and the risk of failing to replicate multi-enzyme/multi-strain pathways when using isolated bacterial strains. The purpose of this research was to investigate TMA production from dietary precursors in an in-vitro model of the human colon. Methods: TMA production from choline, l-carnitine, betaine and γ-butyrobetaine was studied over 24–48 h using an in-vitro human colon model with metabolite quantification performed using LC–MS. Results: Choline was metabolised via the direct choline TMA-lyase route but not the indirect choline–betaine-TMA route, conversion of l-carnitine to TMA was slower than that of choline and involves the formation of the intermediate γ-BB, whereas the Rieske-type monooxygenase/reductase pathway for l-carnitine metabolism to TMA was negligible. The rate of TMA production from precursors was choline > carnitine > betaine > γ-BB. 3,3-Dimethyl-1-butanol (DMB) had no effect on the conversion of choline to TMA. Conclusion: The metabolic routes for microbial TMA production in the colon model are consistent with observations from human studies. Thus, this model is suitable for studying gut microbiota metabolism of TMA and for screening potential therapeutic targets that aim to attenuate TMA production by the gut microbiota. Trial registration number: NCT02653001 (http://www.clinicaltrials.gov), registered 12 Jan 2016. [ABSTRACT FROM AUTHOR]

The study of interactions between surfactant and salt in aqueous solutions has attracted significant interest in recent years because of their widespread applications and relatively complex behavior. This work reports the systematic study of surface phenomenon and self-aggregation behavior of cationic surfactant cetyltrimethyl ammonium bromide (CTAB) with ammonium nitrate (NH4NO3) salt. Surface and thermodynamic properties of cationic surfactant CTAB with NH4NO3 were investigated at different temperatures using different techniques such as conductometry and surface tensiometery. The surface tension measurement was carried out to find out the critical micelle concentration, free energy of adsorption, free energy of micellization, minimum area per molecule, and surface excess concentration. The study reveals that the process of micellization is spontaneous and exothermic in nature. Conductance measurement was carried out to determine critical micelle concentration, degree of ionization and degree of counter ion binding. Addition of NH4NO3 to the surfactant solutions increase the values of degree of ionization and degree of counter ion binding, although it lowers the values of critical micelle concentration showing that the process of micellization is more favorable and spontaneous. The study is very helpful to develop better understanding about interaction between electrolyte and surfactant, which are used in many applications and in different processes (e.g., pharmaceutical, industrial foaming, drug solubilization, oil recovery, and medium for metal nanoparticle formation). [ABSTRACT FROM AUTHOR]

The combination of enzymolysis of compound enzyme, oxidation of sodium hypochlorite, and cationic etherification of 3‐chloro‐2‐hydroxypropyl trimethyl ammonium chloride (CHPTMA) was selected for the functionalization of rice starch (RS) to better raise the performances. The results showed that the oxidation and etherification could improve the acid and alkali resistance of RS, and enhanced its thermal stability. The crystalline structure of RS was an A‐type, the enzymolysis, oxidation, and etherification did not change the structural type, while the crystallinity degree of RS derivatives was all reduced. The enzymolysis, oxidation, and etherification altered the pasting properties of RS, and could effectively decrease the setback and breakdown of RS. The oxidation of sodium hypochlorite not only damaged RS particles containing no micropores, but also destroyed the particles containing the micropores. The enzymolysis and oxidation more seriously destroyed the crystalline region than cationic etherification. The oxidation could increase the enthalpy change of RS, whereas the enzymolysis and etherification decreased its enthalpy change. In addition, the enzymolysis and oxidation could lead to the evident increase in average size of RS. The cationic etherification was able to improve the adsorption of Cu2+ on RS, whereas the low oxidation could only slightly ameliorate the adsorption of Cu2+. Practical Application: Cationic oxidized microporous rice starch as an adsorbent, slow‐release agent, and flocculant will be well used in food, medicine, pesticide, papermaking, waste water treatment, and so on owing to its abundant micropores, anionic groups, and cationic groups as well as small particle size and narrow size range. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a series of protonated titanate nanotubes (PTNTs) modified by stearyl trimethyl ammonium bromide (STAB) were prepared as supports for Polyethyleneimine (PEI)-based sorbents. The CO 2 adsorption performance was evaluated in a self-assembled fixed bed reactor. The typical sorbents were characterized by XRD, EDS, SEM, HR-TEM, N 2 adsorption-desorption, FT-IR and TGA. Results indicate that the modification significantly improves CO 2 adsorption capacity of the sorbents. The maximum CO 2 adsorption amount of 2.22 mmol/g was obtained over the modified PEI-based sorbent in 2% CO 2 /air. Based on the characteristic analysis, the formation of creviced nanotubes, instead of intact nanotubes, is testified because of the modification. Such unique nanotubes possess the higher BET surface area and larger pore volume, which enables more PEI to uniformly distribute on the surface of modified PTNT supports. Especially, it is easier for PEI to enter the inner pores through the crevice than from tube orifices, avoiding pore blockage and facilitating CO 2 diffusion in pores. The abundant amine-sites and small internal diffusion resistance endow the modified sorbent with large CO 2 adsorption capacity. In addition, the PEI/PTNT adsorbent displays good thermal stability and reusability. Graphical abstract Image 1 Highlights • Creviced nanotubes instead of intact nanotubes are formed after introducing stearyl trimethyl ammonium bromide. • The formation of the creviced nanotubes is favorable for the exposure of amine-sites. • The increased accessible amine-sites on the modified nanotubes improve the CO 2 adsorption. • The modified amine-based sorbents display good thermal stability and reusability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The effect of surfactant on the dewaterability of microalgae was investigated. • Dose of SDS and Triton X-100 caused a significant deterioration in dewaterability. • CTAB is found as suitable pretreatment to improve microalgae dewaterability. • 140% biomass recovery efficiency is obtained. Abstract The application of pressure filtration in microalgae harvesting requires chemical pretreatment in order to reduce membrane fouling and to increase water flux. Surfactants have shown potential to enhance microalgae dewaterability by charge neutralization, bridging and releasing extracellular polymeric substances (EPS) and bound water. In this study, the effect of three surfactants including anionic sodium dodecyl sulfate (SDS), non-ionic triton X-100 and cationic cetyl trimethyl ammonium bromide (CTAB) on the dewaterability of Chlamydomonas sp. was investigated. Filtration fluxes and biomass concentrations were used to evaluate the microalgae dewaterability. Based on the results, SDS and Triton X-100 had a negative effect on the dewaterability of microalgae biomass. However, CTAB improved the dewaterability by decreasing the reversible and irreversible fouling resistance. The optimum dosage of CTAB was found to be 1500 mg/L, and resulted in 95.8% and 140% improvement on average water flux and biomass recovery efficiency, respectively. [ABSTRACT FROM AUTHOR]

Lavender fragrance (LF) was encapsulated successfully in ORMOSIL (organically modified silica) via the sol‐gel approach. Silane precursor‐ethylsilicate (TEOS) was modified with methyltrimethoxysilane (MTMS) to enhance the mechanical strength and compatibility of the wall material. Hexadecyl trimethyl ammonium bromide (CTAB) was added as surfactant and polymer for the formation of nanospheres. An encapsulation efficiency of 96.36% was achieved under optimal conditions (water/ethanol ratio of 2 : 1, with pH 9.5, and with a surfactant concentration of 25 mM). Moreover, a scanning electron microscope (SEM) image of the LF nanospheres showed that the nanospheres were spherical with good dispersibility. The Fourier transform infrared spectroscopy (FTIR) analysis indicated that LF was successfully encapsulated in organically modified silica. The result of thermogravimetric (TG) analysis showed that the nanospheres had excellent thermal stability. Furthermore, the SEM image of aromatic wallpaper indicated a successful application of the LF nanospheres in wallpaper. The ORMOSIL lavender fragrance nanospheres were arranged uniformly and spherically with mean diameter sizes 220.5 nm. 96.36% of encapsulation efficiency was achieved in optimal conditions. [ABSTRACT FROM AUTHOR]

A kinetic study of the oxidation of thiosulphate (S2O3 2-) by hexacyanoferrate (III) ([Fe(CN)6]3-) is carried out in the presence of cetyl trimethyl ammonium bromide (CTAB) reverse micelles. The reaction obeys first order kinetics with respect to each of the reactants at all values of W, {W= [H2O]/[CTAB]}. In the reverse micellar medium, the reaction is much slower compared to that in the aqueous medium due to lower micropolarity of the water pools which does not facilitate an anion-anion reaction. The second order rate constant (k2) increases as the value of W increases up to a value of 8.88 and remains constant thereafter. The effect of CTAB concentration is explained by the modified Berezin pseudo phase model for weakly bound reactants leading to the conclusion that it is also valid for the reverse micelles. [ABSTRACT FROM AUTHOR]

Wheat straws (WS) were pretreated by a two-step pretreatment for enhanced enzymatic hydrolysis. The raw wheat straw (RWS) was firstly soaked in microwave-assisted NaOH solution at the presence of a mixed solution of H2O2 and hexadecyl trimethyl ammonium chloride (HTAC), and the residue was put into methyl orange (MO) solution to obtain the final substrate for enzymatic hydrolysis. It was interesting to find that the WS after the first step of the pretreatment could effectively remove MO in the second step of the pretreatment with the highest removal efficiency of 98.86% at the MO concentration of 25 mg/L and at the adsorbent-adsorbate ratio of 0.8%. Meanwhile, the enzymatic hydrolysis efficiency of the WS that was pretreated by the two steps was higher than that of the RWS as well as the first-step-pretreated WS. Enzymatic hydrolysis experiment showed that the glucose concentration after 48-h hydrolysis was 4.85 g/L at the solid loading of 5%, compared with the RWS of 0.90 g/L and the first-step-pretreated WS of 4.33 g/L. This suggested that the two-step pretreatment method could not only make WS as a good adsorbent but also a more biodegradable lignocellulosic material. Characterization analysis showed that the specific surface area and the cellulose content of the WS were both increased after the two-step pretreatment, indicating that the pretreatment method was significant to properly utilizing WS as biosorbent and biofuel. Besides, a possible mechanism for the effect of the pretreatment on the WS was proposed. [ABSTRACT FROM AUTHOR]

Abstract: A new method is developed to measure the phase-transition temperatures in artificial phospholipid membranes. This method is based on studying the temperature dependence of dark conductivity and photoconductivity in a symmetric cell with current-conducting indium-tin oxide (ITO) electrodes. Internal electron photoemission into a thin liposome layer is induced by visible and near IR light from the ITO electrodes. This method is applied to study the lyotropic phases in 1,2-dipalmitoyl-rac-glycero-3-phosphocholine (DPPC) and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) with ethylene glycol (EG) and glycerol (G). The results of time-of-flight measurements are used to calculate the carrier mobilities in liposome vesicles. The measurement results are compared with the results obtained by dc conductometry. We are the first to detect the effect of a positive temperature coefficient of resistivity in a liquid-crystal phase. The proposed method makes it possible to detect the phase transitions in lyotropic liquid-crystal systems and, hence, can be used to create biocompatible drug carriers based on thermosensitive liposomes. [ABSTRACT FROM AUTHOR]

Reaction of 2-chloro-N-(2,2-dichloro-1-cyanovinyl)acetamide with dimethylamine gave 5-(dimethylamino)-2-[(dimethylamino)methyl]-1,3-oxazole-4-carbonitrile, where aliphatic dimethylamino group was regioselectively alkylated with iodomethane. The resulting trimethylammonium salt reacted diastereoselectively with aromatic aldehydes to form new substituted 2-(oxiran-2-yl)-1,3-oxazoles. [ABSTRACT FROM AUTHOR]

Three kinds of organic rectorites (ORECs) were prepared by selecting dodecyl trimethyl ammonium chloride (1231), lauryl dimethyl benzyl ammonium chloride (1227) and stearyl trimethyl ammonium chloride (1831) as organic modifiers to modify Na-REC. Na-REC and ORECs modified asphalts were prepared by using the melting intercalation method. The effect of organic reagents on hydrophilicity of Na-REC was investigated by using hydrophilicity test. The result indicates that 1831-OREC shows the best lipophilicity. Microstructures of Na-REC, ORECs and their modified asphalts were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) tests. Results show that 1831-OREC has the largest interlayer spacing, followed by 1227-OREC. Only 1831-OREC in modified asphalt forms part-exfoliated nanostructure. Effects of ORECs on physical properties, thermal storage stability were studied by penetration, softening point, ductility and viscosity test. It is concluded that introduction of Na-REC and ORECs enhances high temperature property but has the bad effect on low temperature cracking resistance of asphalt. 1831-OREC has the best modification effect on asphalt. Moreover, the 1831-OREC modified asphalt shows the best thermal storage stability. Morphologies of modified asphalts were investigated by atomic force microscope (AFM) test. The result shows that Na-REC and ORECs in asphalt matrix act as nucleators which can contribute to heterogeneous nucleation of asphaltenes. [ABSTRACT FROM AUTHOR]

Kraft lignin is currently under-utilized since it is primarily used as fuel in pulping processes. However, it can be used as a raw material to prepare a functional polymer such as flocculant. A cationic lignin polymer was synthesized via graft polymerization of lignin and [2-(methacryloyloxy)ethyl] trimethylammonium chloride (METAC) in an acidic environment (i.e., a heterogeneous system). The reaction, which was optimized under the conditions of pH 4.0, METAC/lignin ratio of 1.8 mol/mol, 3 h, 80 °C, 0.3 mol/L of lignin concentration, and 1.5 wt % of initiator dosage, generated a lignin-graft-PMETAC polymer having 2.93 mequiv/g charge density and 1.53 × 106 g/mol molecular weight. The lignin-graft-PMETAC polymer can be dissolved in water (at 10 g/L concentration) and a pH range of 0.5-13. The flocculation performance of the polymer was evaluated in a 0.25 wt % kaolin suspension using a particle dispersion analyzer, and the results demonstrated the superiority of the lignin-graft-PMETAC polymer to unmodified lignin and PMETAC. These results confirmed that lignin-graft-PMETAC polymer could replace PolyMETAC (i.e., PMETAC, a synthetic polymer) as a flocculant, which promotes the use of sustainable products in industry. This paper introduces a new process for inducing a cationic lignin-based flocculant. [ABSTRACT FROM AUTHOR]

Collecting performance and adsorption behaviors and mechanisms of two quaternary ammonium salts, dodecyltrimethyl ammonium chloride (DTAC) and cetyltrimethyl ammonium chloride (CTAC), on illite particles have been investigated through flotation tests, adsorption analysis, zeta potential, FTIR measurements and fluorescence spectroscopy. Adsorption analysis revealed that the adsorbed amount of surfactants on mineral surface increases by increasing the pulp pH or by increasing the length of carbon chains of surfactants. Therefore, at same concentrations, CTAC due to its longer carbon chains has a larger adsorption density on illite surface than DTAC, which was measured by FTIR analysis and zeta potential measurements. As compared to DTAC, CTAC showed much better collecting properties as it has higher I 3 /I 1 value and a lower critical micelle concentration (CMC) value, which was analyzed by pyrene fluorescence observations. However, decrease in recovery by CTAC in an alkaline solution was mainly due to the complete adsorption of CTAC molecules on mineral particles, hence, its insufficient concentration in the pulp was unable to stabilize the flotation froth. From the results of flotation behaviors and adsorption mechanisms, it is concluded that CTAC is much more efficient surfactant than DTAC in relation to flotation separation of illite. [ABSTRACT FROM AUTHOR]

The effect of cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) on base hydrolysis of iron(II)-triazine complexes viz., tris((3-(4-phenyl)-2-pyridyl)-5,6-bis(4-phenyl)-1,2,4-triazine)iron(II), Fe(PPDT) 3 2+ and its sulphonated analogue, tris(3-(4-(4-phenylsulphonic acid)-2-pyridyl)-5,6-bis(4-phenyl sulphonic acid)-1,2,4-triazine)iron(II), Fe(PPDTS) 3 7‐ has been studied under pseudo -first order conditions at 25, 35, 45 and 55 °C. These reactions are first order with respect to the substrate and hydroxide ion. The rate of base hydrolysis of Fe(PPDT) 3 2+ decreases with the increase in ionic strength in both aqueous and CTAB media whereas the effect is minimal in SDS medium. In the case of Fe(PPDTS) 3 7‐ , the opposite is seen i.e., the rate of hydrolysis increases with the increase in ionic strength in both the aqueous and SDS media whereas in CTAB medium it has little effect. Specific rate constants ( k 2 ) and activation parameters, E a , ΔH # , ΔS # and ΔG # have also been evaluated. The results obtained suggest that these reactions occur essentially by the same mechanism in aqueous and micellar media. About 10 4 times catalysis and 5 times inhibition were noticed in CTAB and SDS media respectively when compared to aqueous medium. The observed catalysis is ascribed to electrostatic and hydrophobic interactions between hydroxide and CTAB ions, whereas the inhibition is attributed to the electrostatic repulsions between hydroxide ion and dodecyl sulphonate anions. Density functional theory (DFT) calculations were found to support the experimental results. [ABSTRACT FROM AUTHOR]

Modified H-type ZSM-5 (HZSM-5) catalysts were prepared using hexadecyl trimethyl ammonium bromide (CTAB) as mesopore templates to enhance the activity for the catalytic fast pyrolysis of rice straw for aromatics compounds. A certain quantity of CTAB added into the HZSM-5 (HZ) forming hierarchical structure exhibited an improvement in the yield of the aromatics and a decrease in the yield of coke in comparison with that of bare HZ. In contrast, excessive CTAB addition resulted in a decrease in aromatic yield and an increase in coke yield. The effects of crystallinity, textural properties, morphological structure and acidity distribution on the production of aromatic compounds were measured by XRD, BET, TEM and NH 3 -TPD. The good crystallinity, small amount of mesopore formation and highest total acidity discovered in HZ-0.01 (the mole ratio of CTAB/SiO 2 is 0.01) provided the highest aromatic compound yield of 26.8% and the lowest coke yield of 39.2%. [ABSTRACT FROM AUTHOR]

Cationic polymers possess significant potential in various biomedical applications due to their favorable interactions with biocomponents in aqueous media, which is related to their inherent structure and associated water structure. This work presents the development of a novel biodegradable cationic polymer with specific associated water structure and unique interactions with biocomponents. Bioinspired branched dicationically-charged phosphodicholine-chitosan (PdCCs) with different substitute degree were synthesized via Atherton-Todd reaction. As compared with monocationically charged N -(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC), thermal analysis confirmed the existence of the freezing bound water surrounding PdCCs due to the introduction of branched dicationically-charged PdC moiety. Fluorescence spectra revealed that PdCCs induced much less conformational change of bovine serum albumin than HTCC. Antibacterial and hemolysis assay showed that PdCCs and HTCC displayed high antibacterial activities against Escherichia coli and Staphylococcus aureus with different bacterial-type selectivity, and PdCCs showed higher selectivity to kill bacteria over red blood cell than HTCC. Furthermore, PdCCs-immobilized antibacterial surfaces exhibited better hydrophilicity and less protein adsorption than HTCC-immobilized antibacterial surfaces. These results indicated that branched dicationic PdC with capacity to restrain the freezing bound water may provide a good choice for developing cationic polymers for therapeutic applications. [ABSTRACT FROM AUTHOR]

Background: Polysaccharides can alleviate obesity in mammals; however, studies on mechanism of this alleviation are limited. A few studies have indicated that polysaccharides improve obesity by regulating the metabolism of the body. Therefore, a metabolomics approach, consisting of high resolution nuclear magnetic resonance (NMR) spectroscopy and a multivariate statistical technique, was applied to explore the mechanism of the protective effects of lentinan and Flos Lonicera polysaccharides (LF) on high-fat diet (HFD) induced obesity. Methods: In this study, rats were randomly divided into three groups: control diet (CD), HFD, and HFD supplemented with a mixture of lentinan and Flos Lonicera polysaccharide. Histopathological and clinical biochemical assessments were also conducted. A combination of a NMR metabolomics study and a multivariable statistical analysis method to distinguish urinary and fecal metabolites was applied. Results: Significant obesity symptoms appeared in HFD rats (for example, significant weight gain, epididymal adipose accumulation and lipid deposition in hepatocytes), which was attenuated in the LF group. Additionally, the HFD induced a reduction of choline, citrate, pyruvate and glycerol and increased the levels of trimethylamine oxide (TMAO) and taurine. Of note, these metabolic disorders were reversed by LF intervention mainly through pathways of energy metabolism, choline metabolism and gut microbiota metabolism. Conclusions: LF supplementation had a re-balancing effect on the disturbed metabolic pathways in the obese body. The results of this study validate the therapeutic effect of the compound polysaccharide--LF in obesity and described the biochemical and metabolic mechanisms involved. [ABSTRACT FROM AUTHOR]

Montmorillonite (MMT) clay platelets were successfully encapsulated in poly(methyl methacrylate-co-ethyl acrylate) [poly(MMA-co-EA)] matrix by an in situ suspension polymerization, and evaluated for their plugging behaviors in single-sand pack tube models. Swelling behaviors of the poly(MMA-co-EA)/MMT nanocomposites in various salinity water were also investigated. Results showed that the poly(MMA-co-EA)/MMT nanocomposites had a spherical morphology and their particle sizes mainly range from 10 to 120 µm by scanning electron microscopy (SEM) analysis. X-ray diffraction indicated that the existing of MMT layers in the polymer matrix was mainly in exfoliated form; this was consistent with transmission electron microscopy analysis. The thermal stability of poly(MMA-co-EA)/MMT nanocomposites were effectively improved after adding the MMT by thermogravimetric analysis. Furthermore, the selected nanocomposites containing MMT (1.0 wt%) provided an effective plugging in sand pack tubes of high permeability, and plugging rate was up to approximately 85.0%. [ABSTRACT FROM AUTHOR]

In this work; we investigated the differential interaction of amphiphilic antimicrobial peptides with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid structures by means of extensive molecular dynamics simulations. By using a coarse-grained (CG) model within the MARTINI force field; we simulated the peptide-lipid system from three different initial configurations: (a) peptides in water in the presence of a pre-equilibrated lipid bilayer; (b) peptides inside the hydrophobic core of the membrane; and (c) random configurations that allow self-assembled molecular structures. This last approach allowed us to sample the structural space of the systems and consider cooperative effects. The peptides used in our simulations are aurein 1.2 and maculatin 1.1; two well-known antimicrobial peptides from the Australian tree frogs; and molecules that present different membrane-perturbing behaviors. Our results showed differential behaviors for each type of peptide seen in a different organization that could guide a molecular interpretation of the experimental data. While both peptides are capable of forming membrane aggregates; the aurein 1.2 ones have a pore-like structure and exhibit a higher level of organization than those conformed by maculatin 1.1. Furthermore; maculatin 1.1 has a strong tendency to form clusters and induce curvature at low peptide-lipid ratios. The exploration of the possible lipid-peptide structures; as the one carried out here; could be a good tool for recognizing specific configurations that should be further studied with more sophisticated methodologies. [ABSTRACT FROM AUTHOR]

The corrosion inhibition performances of octadecylamine (OCT) and tetradecyl trimethyl ammonium bromide (TTAB) for carbon steels in H 2 S and CO 2 brine solution were investigated by weight loss, potentiodynamic polarization, molecular dynamic simulation and XPS analysis. TTAB showed better inhibition effects on H 2 S and CO 2 induced corrosion than OCT. Synergistic corrosion inhibition effect was found between OCT and TTAB with proper mass ratios and the best inhibition performance was achieved with 10 mg L −1 OCT and 20 mg L −1 TTAB. The synergism was correlative to the fractional free volume of the inhibitor film of OCT and TTAB. [ABSTRACT FROM AUTHOR]

Cyanobacteria and their toxins present potential hazard to consumers of water from lakes, reservoirs and rivers, thus their removal via water treatment is essential. The capacity of nano-composites of Octadecyltrimethyl-ammonium (ODTMA) complexed with clay to remove cyanobacterial and their toxins from laboratory cultures and from lake water, was evaluated. Column filters packed with micelles of ODTMA complexed with bentonite and granulated were shown to significantly reduce the number of cyanobacteria cells or filaments and their corresponding toxins from laboratory cultures. Fluorescence measurements demonstrated that cyanobacteria cells lost their metabolic activity (photosynthesis) upon exposure to the micelle (ODTMA)–bentonite complex, or ODTMA monomers. The complex efficiently removed cyanobacteria toxins with an exceptional high removal rate of microcystins. The effectiveness of the complex in elimination of cyanobacteria was further demonstrated with lake water containing cyanobacteria and other phytoplankton species. These results and model calculations suggest that filters packed with granulated composites can secure the safety of drinking water in case of a temporary bloom event of toxic cyanobacteria. [ABSTRACT FROM AUTHOR]

A simple and rapid UPLC-MS/MS method to simultaneously determine gemcitabine and its L-carnitine ester derivative (2'-deoxy-2', 2'-difluoro-N-((4-amino-4-oxobutanoyl) oxy)-4-(trimethyl amm-onio) butanoate-cytidine, JDR) in rat plasma was developed and validated. The conventional plasma sample preparation method of nucleoside analogues is solidphase extraction (SPE) which is time-consuming and cost-expensive. In this study, gradient elution with small particles size solid phase was applied to effectively separate gemcitabine and JDR and protein precipitation pretreatment was adopted to remove plasma protein and extract the analytes with high recovery(>81%). Method validation was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 5-4000 ng/ml for JDR and 4-4000 ng/ml for gemcitabine, respectively.The lower limit of quantitation (LLOQ) of gemcitabine and JDR was 4 and 5 ng/ml, respectively. The intra-day and inter-day precision and accuracy results were within the acceptable limits. Finally, the developed method was successfully applied to investigate the pharmacokinetic studies of JDR and gemcitabine after oral administration to rats. [ABSTRACT FROM AUTHOR]

N -[(2-hydroxyl)-propyl-3-trimethyl ammonium] chitosan chloride (HTCC) was synthesized using 1-allyl-3-methylimidazole chloride (AmimCl) as a homogeneous green reaction media. The effects of polymer concentration, temperature, cation valence, anion type and concentration of inorganic salt, and degree of substitution (DS) on the rheological properties of HTCC were investigated. The apparent viscosity indicated that HTCC solution was a typical pseudoplastic fluid, which could be described by Ostwald de Waele and Cross-empirical models. The viscoelastic properties showed the formation of gel-like structures. Temperature showed slight effect on the apparent viscosity of HTCC solution, while the DS of HTCC showed remarkable effect on the apparent viscosity. At a low shear rate, the apparent viscosities of HTCC solution increased firstly with an increase of c NaCl from 0 to 40 mmol/L, and then decreased with further increasing c NaCl to 60 mmol/L. At a high shear rate, the opposite trends were observed. The variation of HTCC molecular construction under different inorganic salt conditions was confirmed by scanning electron microscopy, meanwhile, the variation mechanism was proposed. [ABSTRACT FROM AUTHOR]

Clinoptilolite nano-particles (CNP) were modified by hexadecyltrimethyl ammonium bromide surfactant (HDTMA) and dithizone (DZ). The modified zeolite was then used for the modification of carbon paste electrode (CPE). The resulted CNP-HDTMA-DZ-CPE was finally used for the voltammetric determination of Sn(II) in aqueous solution. The raw and modified CNP was characterized by SEM-EDX, BET, TG-DTG and FTIR techniques. The best voltammetric response was obtained in 0.1 mol L −1 NaNO 3 + HCl at pH 2.2 as supporting electrolyte. The electrode showed a linear response in the concentration range of 1 × 10 −8 to 1 × 10 −2 mol L −1 Sn(II) with LOD about 9 × 10 −9 mol L −1 Sn(II). The electrode showed good selectivity and applicability for the determination of Sn(II) in real samples such as river water, an steel company wastewater, tomato paste and a canned tuna fish. [ABSTRACT FROM AUTHOR]

A stable SiO2 material marked as CTAB-Ms(x) was synthesized by a novel sol-gel method. It was modified with hexadecyl trimethyl ammonium bromide (CTAB), which resulted in high adsorption capacity. Its microstructure and surface functional groups were characterized by scanning electron microscope, transmission electron microscope and Fourier transform infrared. The results showed that CTAB-Ms(x) had a core/shell structure in which the core was a CTAB micelle and the shell was SiO2. The prepared material was applied to adsorb bisphenol A (BPA). Pseudo-first-order kinetics equation, pseudo-second-order kinetics equation, Langmuir adsorption isotherm model, Temkin adsorption isotherm model, and thermodynamic equations were used to fit and analyze the experiment results. The theoretical maximum adsorption capacities calculated according to linear and non-linear forms of the Langmuir isotherm were 370.37 mg·g-1 and 198.80 mg·g-1, and the adsorption equilibrium time was 120 min. A mechanism study showed that the high adsorption capacity was attributed to the solubilization effect of the CTAB micelle. [ABSTRACT FROM AUTHOR]

The synthesis of high activity TiO-CTAB-SiC composite possessing the microwave absorption capacity has been reported. Herein, the commercial Silicon carbide (SiC) particles were used as the microwave absorbent and supporter. TiO nanopowders were loaded on the surface of SiC modified by hexadecyl trimethyl ammonium bromide (CTAB) via the hydrothermal route. The as-prepared TiO-CTAB-SiC composite was characterized by X-ray diffraction, field-emission scanning electron microscopy, Fourier transformed infrared spectra, inductively coupled plasma-atomic emission spectrometry and fluorescence emission (PL). Its photocatalytic activity was evaluated by the degradation of rhodamine B in the microwave discharge electrodeless lamp (MDEL) system. The experimental results showed that TiO-CTAB-SiC composite exhibited obviously higher photocatalytic activity in the MDEL system compared with pure TiO nanopowders. Their reusability and separation performance were evaluated by recycling experiments. The reasons for the improvement in photocatalytic performance were discussed in detail. [ABSTRACT FROM AUTHOR]

A new montmorillonite intercalation nickel compound (MINC) was devised and synthesized. MINC was modified by cetyl trimethyl ammonium bromide to obtain organic MINC (OMINC). The results of X-ray diffraction show that the layer spacing was expanded by nickel compound and cetyl trimethyl ammonium bromide, indicating that OMINC was prepared successfully. OMINC was further incorporated into polypropylene (PP)/intumescent flame retardant (IFR) system for preparing PP/IFR/OMINC nanocomposites via melt blending. In thermogravimetric analysis, PP/IFR/OMINC nanocomposites exhibit an enhanced thermal behavior and residue amount. Vertical burning test (UL-94) and limited oxygen index results show that PP/IFR/OMINC nanocomposites have excellent flame retardance, i.e. the limited oxygen index value at 29.5 and UL-94 V0 level for PP/IFR/4 wt% OMINC nanocomposites. According to cone calorimeter testing, the addition of OMINC brings an efficient reduction of flammability parameters, such as peak heat release rate, total heat release, and smoke production rate. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Facile synthesis of poly (ether sulfone)-based anion exchange membranes (AEMs) bearing flexible pendent quaternary ammonium (QA) groups for fuel cells is reported. (2,3-Epoxypropyl) trimethyl ammonium chloride (EPTMAC) is directly grafted onto the hydroxyl-bearing poly (ether sulfone) (PES) backbone via one-step ring-opening reaction to introduce ion conductive moieties. This scheme is more straightforward than the conventional two-step functionalization approach via chloromethylation or radical-initiated bromination and Menshutkin reactions. This method can be used to control the degree of functionalization of QA-containing PES easily. 2D nuclear overhauser effect spectroscopy (NOESY) shows that QA groups aggregate and self-assemble in the functionalized-PES solutions which are in favor of fabricating a membrane with phase separation morphology, as well as confirmed by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). These resulting AEMs exhibit reasonable hydroxide conductivity, low water uptake, high power density, and desirable durability in a single fuel cell. This suggests that they are good candidates for fuel cells. [ABSTRACT FROM AUTHOR]

All proteins are synthesized by the ribosome, a macromolecular complex that accomplishes the life-sustaining tasks of faithfully decoding mRNA and catalyzing peptide bond formation at the peptidyl transferase center (PTC). The ribosome has evolved an exit tunnel to host the elongating new peptide, protect it from proteolytic digestion, and guide its emergence. It is here that the nascent chain begins to fold. This folding process depends on the rate of translation at the PTC. We report here that besides PTC events, translation kinetics depend on steric constraints on nascent peptide side chains and that confined movements of cramped side chains within and through the tunnel fine-tune elongation rates. [ABSTRACT FROM AUTHOR]

TiO2-SiO2 composites were synthesized using cetyl trimethyl ammonium bromide (CTAB) as the structure directing template. Self-assembly hexadecyltrimethyl- ammonium bromide TiO2-SiO2/(CTAB) were soaked into silver nitrate (AgNO3) aqueous solution. The Ag-TiO2-SiO2(Ag-TS) composite were prepared via a precipitation of AgBr in soaking process and its decomposition at calcination stage. Structural characterization of the materials was carried out by various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption and ultraviolet visible spectroscopy (UV-Vis). Characterization results revealed that Ag particles were incorporated into hierarchical TiO2-SiO2 without significantly affecting the structures of the supports. Further heating-treatment at 723 K was more favorable for enhancing the stability of the Ag-TS composite. The cyclohexene oxide was the major product in the epoxidation using H2O2 as the oxidant over the Ag-TS catalysts. Besides, the optimum catalytic activity and stability of Ag-TS catalysts were obtained under operational conditions of calcined at 723 K for 2 h, reaction time of 120 min, reaction temperature of 353 K, catalyst amount of 80 mg, aqueous H2O2 (30 wt.%) as oxidant and chloroform as solvent. High catalytic activity with conversion rate up to 99.2% of cyclohexene oxide could be obtainable in water-bathing. The catalyst was found to be stable and could be reused three times without significant loss of catalytic activity under the optimized reaction conditions. [ABSTRACT FROM AUTHOR]

TiO2-SiO2 composites were synthesized using cetyl trimethyl ammonium bromide (CTAB) as the structure directing template. Self-assembly hexadecyltrimethyl- ammonium bromide TiO2-SiO2/(CTAB) were soaked into silver nitrate (AgNO3) aqueous solution. The Ag-TiO2-SiO2(Ag-TS) composite were prepared via a precipitation of AgBr in soaking process and its decomposition at calcination stage. Structural characterization of the materials was carried out by various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption and ultraviolet visible spectroscopy (UV-Vis). Characterization results revealed that Ag particles were incorporated into hierarchical TiO2-SiO2 without significantly affecting the structures of the supports. Further heating-treatment at 723 K was more favorable for enhancing the stability of the Ag-TS composite. The cyclohexene oxide was the major product in the epoxidation using H2O2 as the oxidant over the Ag-TS catalysts. Besides, the optimum catalytic activity and stability of Ag-TS catalysts were obtained under operational conditions of calcined at 723 K for 2 h, reaction time of 120 min, reaction temperature of 353 K, catalyst amount of 80 mg, aqueous H2O2 (30 wt.%) as oxidant and chloroform as solvent. High catalytic activity with conversion rate up to 99.2% of cyclohexene oxide could be obtainable in water-bathing. The catalyst was found to be stable and could be reused three times without significant loss of catalytic activity under the optimized reaction conditions. [ABSTRACT FROM AUTHOR]

The system of alcohol (C8OH) and hexadecyl trimethyl ammonium bromide (CTAB) was studied by molecular dynamics simulation, and the cylindrical (or rod-like) micelles with different endcaps were obtained. The simulation results presented the different terminal structures of the cylindrical (rod-like) micelles. According to the critical packing parameters of the micellar stability theory, the microscopic structures of cylindrical (or rod-like) micelles with different endcaps were analyzed. The shorter rod-like micelle was constituted by the cylindrical body and two swelling spherical endcaps, while the longer cylindrical (or rod-like) micelle had two spherical crown endcaps less than the hemisphere. The models of the cylindrical (rod-like) micelles were presented in detail based on the simulation results and the micellar stability theory. [ABSTRACT FROM PUBLISHER]

The objective of this study was to investigate the effect of L-carnitine (LC), hypotaurine (HT), and taurine (T) on the quality of frozen-thawed chicken semen. Pooled semen samples were divided into seven aliquots (control, 1 mM LC, 5 mM LC, 1 mM HT, 10 mM HT, 1 mM T, and 10 mM T) and subjected to cryopreservation. Postthaw sperm motility was determined by IVOS system and sperm characteristics were assessed with fluorochromes and flow cytometry. The highest sperm motility and the highest percentage of viable sperm were in the HT1 group (P<0.01 and P<0.05) following cryopreservation. After thawing, we observed a higher percentage of sperm without apoptosis and membrane reorganization changes in the LC1 and T1 group when compared to the control (P<0.05). There was a higher percentage of live sperm without lipid peroxidation (LPO) in all treatments (P<0.01; P<0.05), when compared to the control group. The percentage of sperm with high mitochondrial potential significantly increased with LC1, T1, and T10 (P<0.05). Supplementation of the diluent with LC1, LC5, and T1 significantly (P<0.05) reduced DNA susceptibility to fragmentation, compared to the control and HT1 groups. These results indicate that the addition of examined antioxidants improves the quality of cryopreserved chicken semen. [ABSTRACT FROM AUTHOR]

In this paper, konjac glucomannan was cationized by 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (a kind of cationic reagent) as a paper strength agent. The effects of dosage of cationic reagent, cationization time, cationization temperature and the pH of papermaking on paper properties were analyzed. The results showed that when 1% cationic glucomannan (the cationization temperature was 70°C, dosage of cationic reagent was 20% and cationization time was 5 h) was added, tensile index, burst index and folding endurance of the paper were improved by 11.0%, 13.2%, 72.0%, respectively, compared with the control. The results of SEM analysis, FTIR analysis, and elemental analysis illustrated that the addition of paper strengthening agent make fibers combined more closely, and further lead to the increase of paper strength properties. [ABSTRACT FROM PUBLISHER]

This work studied the interactions of an oppositely charged surfactant mixture of oleyl bis(2-hydroxyethyl)methyl ammonium bromide (OHAB) and sodium dodecyl sulfate (SDS) with 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphocholine (DOPC) vesicles as well as the penetration of the OHAB/SDS mixture through model skin, aimed at understanding the relationship between the ability of different surfactant aggregates in solubilizing phospholipid vesicles and their potential in irritating skin. By changing the molar fraction of OHAB (XOHAB), five kinds of aggregates are constructed: OHAB and SDS separately form cationic and anionic small micelles, whereas the OHAB/SDS mixtures form cationic and anionic vesicles at XOHAB = 0.30 and 0.70, respectively, and weakly charged vesicles at XOHAB = 0.50. The mixtures have much lower critical micellar concentrations (CMCs) and much larger aggregates than either OHAB or SDS alone, and the CMC and the size of the OHAB/SDS vesicles decrease with the increase in XOHAB. The phase diagrams indicate that the OHAB/SDS mixtures show much stronger ability in solubilizing the DOPC vesicles than individual OHAB and SDS and decrease in the order of XOHAB = 0.30 > 0.50 > 0.70 ≫ 1.00 > 0. However, the ability of the surfactants in penetrating the model skin decreases reversely, and the penetration of the surfactants are significantly reduced by mixing. These results indicate that the surfactant mixture with a larger aggregate size and a smaller CMC value displays much stronger ability in solubilizing the DOPC vesicles but much weaker ability in penetrating the skin. [ABSTRACT FROM AUTHOR]

A new application of polymer–surfactant aggregates has been developed to remove dilute metallic anions, such as CrO 4 2 − and Fe(CN) 6 3 − , from aqueous solutions. This process uses anionic polymers, such as poly(sodium 4-styrenesulfonate) (PSS) or poly(acrylic acid) (PAA), as a back-bone structure onto which cationic surfactants, such as myristyl trimethyl ammonium bromide (MTAB), form micelle-like aggregates. The resulting structures, called polymer–surfactant aggregates (PSAs), have the ability to remove anions from solutions, and to form larger flocculated aggregates through a process of intermolecular association. The flocculated aggregates can then be separated out from the solution through a settling or coarse filtration step. In the work presented here, the results show that 99% of 0.1 mM Fe(CN) 6 3 − and 80% of 0.2 mM CrO 4 2 − can be removed at optimum dosages. The change in conductivity with the change in surfactant concentration is plotted to reveal changes in the state of the system, and to detect the point of formation of the PSAs. The results indicate that the PSAs, which form at surfactant concentrations well below the critical micellar concentration, are responsible for removing the metallic anions. This process is effective for metallic anion removal over a pH range from 4.5 to 6 and a temperature range from 5 to 50 °C. Furthermore, both salt and organic contaminants do not significantly interfere with the anion removal efficiency. Such a PSA process thus has potential applications for the efficient removal of dilute anions, and metallic anions in particular, during process effluent water treatment. [ABSTRACT FROM AUTHOR]

The influence of water concentrations on phase transformations of a surfactant/co-surfactant/water system is investigated by using all atom molecular dynamics simulations. At higher water concentrations, where surfactant (behenyl trimethyl ammonium chloride, BTMAC) to co-surfactant (stearyl alcohol, SA) ratio is fixed, BTMAC and SA self-assemble into spherical micelles, which transform into strongly interdigitated one dimensional rippled lamellar phases upon decreasing water concentrations. Fragmentation or fusions of spherical micelles of different sizes are evident from the radial distribution functions at different temperatures. However, at lower water concentrations rippled lamellar phase transforms into an L β I phase upon heating. Our simulations reveal that the concentrations of water can influence available space around the head groups which couple with critical thickness to accommodate the packing fraction required for respective phases. This directs towards obtaining a controlling factor to design desired phases important for industrial and medical applications in the future. [ABSTRACT FROM AUTHOR]

In participation of the fifth statistical assessment of modeling of proteins and ligands (SAMPL5), the strength of association of six guests ( 3- 8) to two hosts ( 1 and 2) were measured by H NMR and ITC. Each host possessed a unique and well-defined binding pocket, whilst the wide array of amphiphilic guests possessed binding moieties that included: a terminal alkyne, nitro-arene, alkyl halide and cyano-arene groups. Solubilizing head groups for the guests included both positively charged trimethylammonium and negatively charged carboxylate functionality. Measured association constants ( K ) covered five orders of magnitude, ranging from 56 M for guest 6 binding with host 2 up to 7.43 × 10 M for guest 6 binding to host 1. [ABSTRACT FROM AUTHOR]

Recently DNA with hexadecyltrimethyl ammonium chloride (CTMA) complex has been included in some organic electronic devices. Thermal stability is one of key parameters required for successful applications in different electronic and optoelectronic devices. This work shows a possibility of enhancing thermal stability in this complexes and analyzes origin of this enhancement. Different techniques were applied to explore this issue of solid DNA-CTMA. Results of TGA analysis, DSC calorimetry, FTIR spectroscopy, and analysis of evolved gaseous products convince that chemical composition of DNA-CTMA complex remains fixed at temperatures <200-220 °C. In contrast, broadband dielectric spectroscopy applied to freshly prepared thin films of DNA-CTMA revealed at 150-160 °C a permanent and irreversible change of dielectric properties. This phenomenon may be attributed to a transformation affecting the microstructure. Some experiments were conducted also for the native DNA as a reference. We demonstrate that DNA-CTMA complex chemical composition is more stable at temperatures about 200 °C with respect to DNA which is very important for laser operated optoelectronic applications. [ABSTRACT FROM AUTHOR]

We investigated the influence of the quaternary ammonium salt (QAS) called IM ( N-(dodecyloxycarboxymethyl)- N, N, N-trimethyl ammonium chloride) on yeast cells of the parental strain and the IM-resistant mutant (EO25 IM) growth. The phenotype of this mutant was pleiotropic. The IM mutant exhibited resistance to ethanol, osmotic shock and oxidative stress, as well as increased sensitivity to UV. Moreover, it was noted that mutant EO25 appears to have an increased resistance to clotrimazole, ketoconazole, fluconazole, nystatin and cycloheximide. It also tolerated growth in the presence of crystal violet, DTT and metals (selenium, tin, arsenic). It was shown that the presence of IM decreased ergosterol level in mutant plasma membrane and increased its unsaturation. These results indicate changes in the cell lipid composition. Western blot analysis showed the induction of Pma1 level by IM. RT-PCR revealed an increased PMA1 expression after IM treatment. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) are a type of ionic solvents composed of two components and that have a melting point lower than either of the individual components. DES's can be prepared combining a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA). In this study, benzyl tri-methyl ammonium chloride (BTMAC) is used as the hydrogen bond acceptor, and p-toluene sulfonic acid (PTSA), citric acid (CA), and oxalic acid (OX) are used as the HBD. The physical properties of DES 1 (BTMAC-PTSA), DES 2 (BTMAC-CA), and DES 3 (BTMAC-OX) were investigated at their respective eutectic points. The refractive index, conductivity, density, viscosity, and pH values were measured for the three DES between 293.15 and 333.15 K. As expected, the density, refractive index, and viscosity decreased and the ionic conductivity increased with increasing temperature, whereas, the pH values remained constant. The catalytic activities of the DES were tested in the esterification reaction between acetic acid and butanol. The results showed the superiority of DES 1 (BTMAC: PTSA) which gave the highest conversion of acetic acid and a further parametric study including the effects of catalyst loading, mole ratio, alcohol type, and reusability were conducted using DES 1. The obtained results showed a high applicability of DES for catalytic applications. [ABSTRACT FROM AUTHOR]

In the present study, we reported a convenient route to prepare well dispersed and functionalized K-doped core-shell upconversion nanoparticles (UCP) by layer-by-layer (LbL) assembly of polyelectrolytes. UCP was firstly transferred to aqueous phase using cationic surfactant cetyl trimethyl ammonium bromide (CTAB) via hydrophobic interaction without removing the existing oleic acid (OA). Then the positively charged hydrophilic UCP@CTAB was further alternately deposited with negatively charged [poly (sodium 4-styrenesulfonate)] (PSS), positively charged [poly (allylamine hydrochloride)] (PAH) and negatively charged [poly (acrylic acid)] (PAA). The final carboxyl functionalized UCP@CTAB@PSS@PAH@PAA was then conjugated with monoclonal antibody1 (AB1) of procalcitonin (PCT), resulting in successful detection of PCT antigens based on the immunochromatographic assay (ICA). Linear response was achieved from 0 to 10 ng/mL, and the lowest limit of detection (LLD) was 0.18 ng/mL. [ABSTRACT FROM AUTHOR]

Clinoptilolite nanoparticles (NClin) modified with hexadecyltrimethyl ammonium bromide surfactant (HDTMABr) and Arsenazo III (ARS) was used for the modification of carbon paste electrode. The modified electrode was used for voltammetric determination of Cesium. The peak current of semi-reversible electrochemical peaks of Arsenazo III was decreased by adding cesium to the solution and hence this decrease was used for the determination of cesium in solution. The electrode response can be controlled by diffusion of cesium to the surface of the modified electrode. The modified electrode showed a suitable linear calibration graph in the concentration ranges of 8.4 × 10 −8 –1.0 × 10 −3 , 9.6 × 10 −9 –1.0 × 10 −3 and 8.0 × 10 −9 –1.0 × 10 −3 mol L −1 cesium with detection limits of 3.6 × 10 −8 , 3.0 × 10 −9 and 2.4 × 10 −9 mol L −1 of Cs + for CV, SqW and chronoamperometric methods, respectively. The proposed electrode showed high selectivity for cesium among the tested cations and good recovery results confirmed applicability of the sensor for Cs determination in real samples. [ABSTRACT FROM AUTHOR]

Air floatation, an efficient solid-liquid separation process, was tested as a post treatment technique for phenol removal. The results consider about the practical solutions for certain operations such as efficient solid-liquid separation, attainment of maximized percentage removal, phenol rich solution with Micrococcus lylae cells, and pure water without M. lylae cells. The two processes, biosorption and flotation, can effectively operate in combination and both the sorbent and treated water can be recycled. The effect of various operating parameters, such as initial feed concentration, equilibrium time, biosorbent dose, pH, liquid pool height, surfactant concentration, and air flow rate, was experimentally investigated. The maximum sorption capacity was found to be 303 mg/g at pH 7 and an initial phenol concentration of 500 mg/L. The higher floatability of M. lylae was obtained in a maximum time of 10 min. In addition, the adsorption isotherm and kinetic studies revealed that the biosorption process followed the Dubinin-Radushkevich model ( R2 = 0.982) and pseudo-first order kinetics with a kinetic constant of 2.6537/day. The adsorbed chemical species was identified by Fourier transform infrared (FTIR) spectroscopy. Electrokinetic measurements were carried out to determine the isoelectric point of the bacteria. The zeta potential profile of the bacteria was affected by the presence of phenol at different pH values. The recovery of phenol loaded biomass and final traces of phenol by flotation were found to be 99.91%. [ABSTRACT FROM AUTHOR]

Treatment of Jurkat T cells with the dynamin inhibitor, myristyl trimethyl ammonium bromides (MiTMAB) caused cytokinesis impairment and apoptotic DNA fragmentation along with down-regulation of anti-apoptotic BAG3 and Mcl-1 levels, Bak activation, mitochondrial membrane potential (Δψm) loss, activation of caspase-9 and -3, and PARP cleavage, without accompanying necrosis. Bcl-xL overexpression completely abrogated these MiTMAB-induced mitochondrial damage and resultant caspase cascade activation, except for impaired cytokinesis and down-regulated BAG3 and Mcl-1 levels. Additionally, autophagic responses including Akt-mTOR pathway inhibition, formation of acridine orange-stainable acidic vesicular organelles, LC3-I/II conversion, and p62/SQSTM1 down-regulation were detected regardless of Bcl-xL overexpression. The autophagy inhibitors 3-methyladenine and LY294002 enhanced MiTMAB-induced apoptotic sub-G 1 peak, BAG3 and Mcl-1 down-regulation, Bak activation, Δψm loss, and caspase activation. These results indicate that MiTMAB-caused cytokinesis failure leads to concomitant induction of apoptosis and cytoprotective autophagy, and suggest that inhibition of autophagy is a promising strategy to augment antitumor activity of MiTMAB. [ABSTRACT FROM AUTHOR]

In aqueous solutions containing isopropanol (IPA), within the range of 0–100 g/L, the micellization behaviors of binary surfactant mixtures of amphoteric sodium 3-( N -dodecyl ethylenediamino)-2-hydropropyl sulfonate (C12AS) and cationic octadecyltrimethyl ammonium bromide (OTAB) were investigated by three techniques including tensiometry, conductometry and isothermal titration microcalorimetry (ITC). Based on extant theories and models (such as, the regular solution theory, the pseudophase separation model, the Rubingh’s model, etc.), the effects of IPA on the molar fraction of components in mixed micelles, the interaction parameters between the two surfactants, and associated thermodynamic parameters have been discussed. The addition of cosolvent IPA results in a change in the conformation of C12AS, as well as affecting the interaction behavior between the two surfactants and a decrease in the hydrophobic effect. The synergistic effects between the two surfactants varies partly with the concentration of IPA. The observations can be used to explain the cause for the abnormal dependence of the molar fraction of components in mixed micelles and the interaction parameters on the concentration of the cosolvent IPA. Thermodynamic parameters further show the effect of IPA on the entropy-driven process of micellization. [ABSTRACT FROM AUTHOR]

We investigate the effect of cetyl-trimethyl-ammonium-bromides (CTAB) concentration on the fluorescence of Rhodamine-6G in water. This spectroscopic study of Rhodamine-6G in presence of CTAB was performed using two-photon-induced-fluorescence at 780 nm wavelength using high repetition rate femtosecond laser pulses. We report an increment of ∼10 % in the fluorescence in accordance with ∼12 % enhancement in the absorption intensity of the dye molecule around the critical micellar concentration. We discuss the possible mechanism for the enhancement in the two-photon fluorescence intensity and the importance of critical micellar concentration. [ABSTRACT FROM AUTHOR]

In this study, mineralized collagen (COL) coatings with controlled loading and release of bone morphogenetic protein (rhBMP-2) as well as enhanced osteogenic differentiation were successfully achieved via the spatially-control of hydroxypropyltrimethyl ammonium chloride chitosan (HACC) within the coatings. The distribution of HACC in the inner part (HACC-IN) or the outer part (HACC-OUT) of the coatings were adjusted by different potential values and negative/positive alternations during alternating potentials assisted electrochemical deposition (AP-ECD). It was found that rhBMP-2 loading capacity was remarkably enhanced with the increased incorporation of HACC due to their strong interaction, and the release behavior was also tuned by HACC location. In general, HACC-IN coatings showed a prominent improvement in cytocompatibility and osteogenic differentiation. The main reason is considered that the inner location of HACC can eliminate the negative effect of HACC to initial cellular adhesion and bring to a sustained rhBMP-2 release behavior due to kinetic modification. An optimized coating in this work could load as high as 4644 ng/cm 2 rhBMP-2 and release only 25% for 14 days, which consequently leads to a better osteogenic differentiation. This study has thus inspired another promising protocol for designing growth factor incorporated bioactive coatings for bone implants with improved osteointegration. [ABSTRACT FROM AUTHOR]

Air entraining agent (AEA) can bring a lot of microbubbles into fresh concrete for improving its fluidity; however, high fluidity has adverse effect on the shootability of wet-mix shotcrete. In order to solve the contradictory issue, the paper developed a new type of green switch air entraining agent (GSAE) that can improve both the pumpability and shootability. The single-admixture and combination tests containing foaming ability and surface tension were performed with Deer agitator and automatic tension meter. The new AEA was developed with two constituents A and B. A was prepared with Sapindus mukorossi(S-1), dodecyl trimethyl ammonium chloride(1231), and polyacrylamide. B was prepared with lauryl sodium sulfate (K12) and silicone oil. The mass mix proportion was S-1 : 1231 : polyacrylamide : K12 : silicone oil = 1 : 0.33 : 0.2 : 0.33 : 0.47. The application method of GSAE proposed that A was premixed with fresh concrete and then B was added at nozzle. Experimental investigation showed that the optimal mixing amount of GSAE was 0.1%–0.2% relative to cement. All performance measured of wet-mix shotcrete with 0.12% GSAE met the first-grade product requirements of the China National Standard. Compared with the conventional type of AEA, the proposed GSAE is capable of effectively improving pumpability and shootability. [ABSTRACT FROM AUTHOR]