Cetylmethylammonium Bromide Research Articles

The effects of calcination on the electrochemical properties of manganese oxides.

Three different crystalline forms of Mn3O4 were successfully prepared by a liquid phase method with different additives. Using XRD, SEM, EDS, BET, compacted density and electrochemical analysis, the effects of different additives on the morphology, phase composition, surface characteristics, specific surface area, electrochemical and other physical and chemical properties of manganese oxides were investigated. The results showed that the rod type Mn3O4 was prepared by mixing ammonia water and anhydrous ethanol in a 1 : 1 ratio and an appropriate amount of cetylmethyl ammonium bromide as the additive. The rod-type Mn3O4 showed a maximum specific surface area of 63.87 m2 g-1 and has the advantages of low compaction density, no introduction of other impurities, and high adsorption potential. It also has excellent electrochemical performance and an impedance of 240 Ω. The specific capacity was as high as 666.5 mA h g-1 at 1C current density and 382.2 mA h g-1 after 200 cycles. The results also showed that the electrochemical performance of Mn2O3 prepared at 700 °C from the rod-type Mn3O4 was the best. When it was used as the anode material of a lithium-ion battery, it showed a high specific capacity of 712.1 mA h g-1 after 200 cycles. Therefore, the rod-type Mn2O3 material has the characteristics of high capacity, low cost and environmental friendliness and is a promising candidate anode material for lithium-ion batteries.

Effect of Process Control Parameters on the Filtration Performance of PAN-CTAB Nanofiber/Nanonet Web Combined with Meltblown Nonwoven.

Nanofibers have potential applications as filters for particles with diameters <10 μm owing to their large specific surface area, macropores, and controllable geometry or diameter. The filtration efficiency can be increased by creating nanonets (<50 nm) whose diameter is smaller than that of nanofibers. This study investigates the effect of process conditions on the generation of nanonet structures from a polyacrylonitrile (PAN) solution containing cation surfactants; in addition, the filtration performance is analyzed. The applied electrospinning voltage and the electrostatic treatment of meltblown polypropylene (used as a substrate) are the most influential process parameters of nanonet formation. Electrospun polyacrylonitrile–cetylmethylammonium bromide (PAN–CTAB) showed a nanofiber/nanonet structure and improved thermal and mechanical properties compared with those of the electrospun PAN. The pore size distribution and filter efficiency of the PAN nanofiber web and PAN–CTAB nanofiber/nanonet web with meltblown were measured. The resulting PAN–CTAB nanofiber/nanonet air filter showed a high filtration efficiency of 99% and a low pressure drop of 7.7 mmH2O at an air flow rate of 80 L/min. The process control methods for the nanonet structures studied herein provide a new approach for developing functional materials for air-filtration applications.

A mechanistic experimental study on the combined effect of Mg2+, Ca2+, and SO42- ions and a cationic surfactant in improving the surface properties of oil/water/rock system

More than half of the discovered hydrocarbon reservoirs in the world are the oil-wet carbonates. Enhanced oil recovery (EOR) from these reservoirs is challenging because of their tendency to retain oil at the rock surface. The use of low salinity (LS) water injection to recover more oil from these types of oil reservoirs has been recommended by several researchers. There are possible mechanisms concerning LS water flooding that have been introduced in the literature; a distinct lack of experimental investigation to enhancing the efficiency of this method is still felt. In this work, a detailed and comprehensive study was carried out on using LS + surfactant (LSS) to improve the surface and interface properties of oil + water + calcite rock samples. In the first step, the point of zero charge of the rock sample was determined. Then, the effect of different salts including MgCl2, CaCl2, and Na2SO4 at different concentrations on improving the oil-water interfacial tension and wettability alteration of the rock surfaces was investigated in the presence and absence of a cationic surfactant, cetyl methylammonium bromide (CTAB), in the operational range of pH. Emulsion formation and adsorption measurement tests were performed for a deep investigation of the performance of the cationic surfactant in the presence of different salts. Finally, waterflooding experiments were carried out and the water/oil relative permeabilities, amount of recovery and wettability alteration were thoroughly investigated for three different injection scenarios.The results showed that the co-presence of magnesium, calcium and sulfate ions all in the presence and absence of CTAB surfactant causes a significant reduction in IFT and contact angle values, especially at the lower ranges of salinity. The addition of divalent cations, i.e., Mg2+ and Ca2+, could reduce the amount of surfactant adsorbed on the calcite rock surfaces, especially in the low ranges of salinities. Also, in flooding tests, an increase in differential pressure between the inlet and outlet faces of the core samples from about 2.9 MPa for LS to about 4.7 MPa for LSS flooding, at the breakthrough time, was observed which was related to the formation of water in oil emulsions during LSS flooding. Comparison of the ratio of the residual to initial oil saturation (Sor/Soi) for different flooding scenarios (i.e., injection of saline water (SW), LS and LSS solutions) indicates that as the salinity of water reduces, the efficiency of CTAB surfactant in improving oil recovery increases.

Poly(lactic acid) microparticles with controllable morphology by hydroxyapatite stabilized pickering emulsions: Effect of pH, salt, and amphiphilic agents

Pickering emulsion and solvent removal technique was used to prepare poly(lactic acid) (PLA) microparticles. Hydroxyapatite nanoparticles (HAp) were used as an emulsion stabilizer and their assembly on the interface was intended to give additional functionality on PLA microparticles. This research aimed to control the structural morphology of PLA microparticles by changing the interfacial adsorption behavior of HAp with different approaches i.e., pH adjustment, salt concentration, propyl gallate (PG) amphiphile and cetylmethylammonium bromide (CTAB) surfactant. Zeta potential and particle size results demonstrated that the changes in surface charge density, double layer repulsion and the aggregation behavior of the modified HAp in different approaches. Such modification is crucial in determining the particle-interface interaction. Results demonstrated that PLA microparticles with deflated-sphere morphology can be obtained by two conditions, i.e., HAp without modification and low salt concentration at pH 4.5. At high alkalinity (pH 10), microparticles with dumbbell morphology can be obtained in the absence of salt, whereas coagulated deflated-spheres morphology dominated in 0.01M and 0.1M salt. To obtained plate-shape morphology, 1.0M salt concentration is required, with the exception of pH 7 wherein a mixture of deflated-sphere and spherical morphology was obtained. In situ hydrophobization of HAp with PG amphiphile produced large deflated microparticles with wrinkled surface which is resulted from the high particle-interface chemical affinity. CTAB modified HAp produced spherical microparticles. However, the interfacial adsorption of HAp on PLA microparticles can be only obtained at 1×10−4M CTAB concentration. In summary, this work demonstrated that interfacial adsorption behavior of colloidal stabilizer is critical in determining the morphology of colloidal coated polymer microparticles.

A rapid method for isolation of genomic DNA from food-borne fungal pathogens.

Food contaminated with fungal pathogens can cause extremely harmful effects to human even when present in low concentrations. Researchers now pay more attention towards rapid DNA extraction for the quick screening, which is highly demanded in diverse research field. Molecular description of many fungal species is identified by different molecular characteristics. Hence, the efficient isolation of genomic DNA and amplification using PCR is a prerequisite for molecular characterization. Here, we used an improved Sodium dodecyl sulfate-Cetyltrimethyl ammonium bromide-Chloroform-isoamyl alcohol method by combining Sodium dodecyl sulfate with cetyl methylammonium bromide without addition of proteinase K, RNase K, and β-mercaptoethanol. To analyze the quality of recovered DNA, this method was compared with the other four routine methods. The present method has been chosen in the study as a preferred method because of easy adaptation to routine laboratories/food industries considering its rapid, sensitivit,y and cost effectiveness involved in the method.

Microemulsion-assisted Zinc Oxide Synthesis: Morphology Control and Its Applications in Photoanodes of Dye-Sensitized Solar Cells

Zinc oxide (ZnO) crystals with structures of hexagonal club (HC), nanoparticle (NP), and hexagonal plate (HP) are synthesized via microemulsion technique by using the surfactants of cationic cetylmethylammonium bromide (CTAB), nonionic Triton® X-100, and anionic docusate sodium (AOT), respectively, and they are used for the photoanodes of dye-sensitized solar cells (DSSCs). Phase diagrams are constructed in mapping the compositions of the microemulsions to guide the synthesis of ZnO crystals. All the synthesized ZnO crystals exhibited wurtzite crystal phase of ZnO in their X-ray diffraction (XRD) patterns, and their morphologies and structures were investigated by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM), respectively. The sub-micro sized HC and HP ZnO crystals are meritorious in the present work as large particles are effective for light-scattering in the photoanode; the nano-sized NP ZnO crystal is meritorious in the present work as small particles are effective for dye adsorption in the photoanode of DSSCs. By using the photoanodes with bi-layer NPs/HPs and NPs/HCs ZnO films for the ZnO-based DSSCs with a novel organic dye (coded DJ149), we obtained good cell efficiencies of 7.40% and 6.95%, respectively. Incident photon-to-current conversion efficiency (IPCE) curves, and UV–vis reflectance spectra are also used to substantiate the results.

Morphological Influence of Polypyrrole Nanoparticles on the Performance of Dye–Sensitized Solar Cells

Polypyrrole (PPy) with various morphologies were synthesized by chemical oxidative polymerization and further used as the counter electrode (CE) in dye–sensitized solar cells (DSSCs). The conventional anionic surfactant, docusate sodium salt (AOT), cationic surfactant, cetylmethyl ammonium bromide (CTAB), and the newly developed polymeric dispersant, poly(oxyethylene)–imide (POEM), were employed in the PPy synthesis. Scanning electron microscopy images (SEM) revealed diversified morphologies of the synthesized PPy nanoparticles with irregular sheet (IS), hierarchical nanosphere (HNS), and nanosphere (NS), corresponded to the choice of the commercial surfactants AOT and CTAB, as well as the home–made POEM, respectively. Fourier transform spectroscopy (FT–IR) and X–ray diffraction (XRD) analysis were used to confirm the PPy structures and crystalline properties. When fabricated into films and used as CE in DSSCs, the PPy–HNS demonstrated the superior cell efficiency of 6.71±0.16% to those of PPy–IS (5.46±0.31) and PPy–NS (6.31±0.24), respectively. The excellent electrocatalytic ability of PPy–HNS was essentially attributed to its high electrochemical surface area (Ae), which was quantitatively calculated through a rotating disk electrode system by using the Koutecky–Levich equation. Brunauer–Emmett–Teller (BET) surface area measurement, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were also used to substantiate the explanation for the DSSC performances.

Environmental effects on the Raman spectra of single walled carbon nanotubes

The radial breathing mode (RBM) is a diameter dependent, resonant Raman active mode of single walled carbon nanotubes (SWNTs). We demonstrate, using three different excitations (explicitly 532, 561, and 785 nm), the influence of ionic surfactants (cetyl methyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS)) on the intensity and frequency of the RBM. It was found that the van der Waals (vdW) interaction, between the water molecules and the SWNTs, induced by the CTAB surfactant was stronger than that induced by the SDS surfactant. The strength of the vdW interaction allowed us to suggest that the surfactants were randomly adsorbed on the surface of the SWNTs.

Pluronic Triblock Copolymer Encapsulated Gold Nanorods as Biocompatible Localized Plasmon Resonance-Enhanced Scattering Probes for Dark-Field Imaging of Cancer Cells

Gold nanorods (GNR) are synthesized using cetylmethylammonium bromide (CTAB) surfactants which function as structure-directing agents. However, CTAB forms a tightly bound cationic bilayer on GNR surface with the cationic trimethylammonium head group exposed to the aqueous media, which is known to be highly toxic in vitro and in vivo. Pluronic is a non-ionic triblock polymer, which can associate with CTAB and form stable CTAB–polymer complexes due to hydrophobic interactions. In this work, two types of Pluronic triblock copolymers were used to encapsulate GNR to reduce their cytotoxicity and improve colloidal and optical stability for biological applications. These formulations were characterized by UV–vis absorption spectra analysis, transmission electron microscopy, cell viability studies, differential interference contrast microscopy and dark-field imaging.

Control of morphology and size of platinum crystals through amphiphilic polymer-assisted microemulsions and their uses in dye-sensitized solar cells

A film of platinum nanostructure crystals is synthesized for the counter electrode (CE) of a dye-sensitized solar cell (DSSC) via an approach of water-in-oil microemulsions in the presence of an amphiphilic polymer, poly(oxyethylene)-segmented imide (POEM). Phase diagrams are constructed in mapping the compositions of the microemulsions to guide the synthesis of platinum nanostructure crystals. The conventional cationic surfactant, cetylmethyl ammonium bromide (CTAB), and anionic surfactant, docusate sodium salt (AOT), are compared with the newly developed POEM for preparing the emulsions. Transmission electron microscopic images reveal that the synthesized Pt nanostructure crystals have diversified morphologies, including nanospindle, nanosquare and nanosphere in correlation with the surfactants of CTAB, AOT, and POEM, respectively. X-ray diffraction patterns of the three Pt crystals indicates the presence of (111), (200) and (220) lattice planes of Pt. The Pt with different morphologies and structures are proved to be influential for catalytic ability when using them as Pt CEs in DSSCs. The DSSC with the CE containing the film of Pt nanospheres demonstrates a significantly improved power conversion efficiency of 9.34%, compared to 7.20% and 8.17% for the corresponding Pt nanosquare and Pt nanospindle films. Fourier transform spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) are also used to substantiate the explanation for the DSSC performance.

Cytotoxicity of serum protein-adsorbed visible-light photocatalytic Ag/AgBr/TiO 2 nanoparticles

Photocytotoxicity of visible-light catalytic Ag/AgBr/TiO 2 nanoparticles (NPs) was examined both in vitro and in vivo. The Ag/AgBr/TiO 2 NPs were prepared by the deposition–precipitation method. Their crystalline structures, atomic compositions, and light absorption property were examined by X-ray diffraction (XRD) patterns, X-ray photoelectron (XPS) intensities, and ultraviolet-visible (UV–vis) diffuse reflectance spectroscopic tools. The Ag/AgBr/TiO 2 NPs appeared to be well internalized in human carcinoma cells as evidenced by transmission electron microscopy (TEM). The cytotoxicity of cetylmethylammonium bromide (CTAB) appeared to be significantly reduced by adsorption of serum proteins in the cellular medium on the NP surfaces. Two types of human cervical HeLa and skin A431 cancer cells were tested to check their viability after the cellular uptake of the Ag/AgBr/TiO 2 NPs and subsequent exposure to an illumination of visible light from a 60 W/cm 2 halogen lamp. Fluorescence images taken to label mitochondria activity suggest that the reactive oxygen species should trigger the photo-destruction of cancer cells. After applying the halogen light illumination for 50–250 min and ∼8 ppm (μg/mL) of photocatalytic Ag/AgBr/TiO 2 NPs, we observed a 40–60% selective decrease of cell viability. Ag/AgBr/TiO 2 NPs were found to eliminate xenograft tumors significantly by irradiating visible light in vivo for 10 min.

Magnetic mesoporous silica nanospheres as DNA/drug carrier

In this study, superparamagnetic magnetite/polystyrene (Fe 3O 4/PS) nanospheres obtained by miniemulsion polymerization have been encapsulated with a thin nonporous silica coating as well as an additional layer of ordered mesoporous silica through a cetylmethyl ammonium bromide (CTAB) templated sol–gel process. The obtained sandwich-like magnetic mesoporous silica nanospheres (M-MSNs) show high magnetization accompanied with typical ordered mesoporous material characteristics, including ordered and accessible mesopores of 4.2 nm in size, high surface area (475 m 2/g) and high pore volume (0.6 cm 3/g). The composite nanospheres also possess monodisperse spherical morphology with a smooth surface, and narrow particle size distribution centered at 225 nm. Adsorption tests of macromolecular salmon sperm DNA and the small-molecular drug rapamycin on the M-MSNs both show high adsorption capacity, demonstrating their promising applicability in enhanced DNA separation or drug/gene delivery.

Effects of DNA Extraction and Purification Methods on Real-Time Quantitative PCR Analysis of Roundup Ready Soybean

The quality of DNA affects the accuracy and repeatability of quantitative PCR results. Different DNA extraction and purification methods were compared for quantification of Roundup Ready (RR) soybean (event 40-3-2) by real-time PCR. DNA was extracted using cetylmethylammonium bromide (CTAB), DNeasy Plant Mini Kit, and Wizard Magnetic DNA purification system for food. CTAB-extracted DNA was also purified using the Zymo (DNA Clean & Concentrator 25 kit), Qtip 100 (Qiagen Genomic-Tip 100/G), and QIAEX II Gel Extraction Kit. The CTAB extraction method provided the largest amount of DNA, and the Zymo purification kit resulted in the highest percentage of DNA recovery. The Abs260/280 and Abs260/230 ratios were less than the expected values for some of the DNA extraction and purification methods used, indicating the presence of substances that could inhibit PCR reactions. Real-time quantitative PCR results were affected by the DNA extraction and purification methods used. Further purification or dilution of the CTAB DNA was required for successful quantification of RR soybean. Less variability of quantitative PCR results was observed among experiments and replications for DNA extracted and/or purified by CTAB, CTAB+Zymo, CTAB+Qtip 100, and DNeasy methods. Correct and repeatable results for real-time PCR quantification of RR soybean were achieved using CTAB DNA purified with Zymo and Qtip 100 methods.

The Hemolymph of the Ascidian Styela plicata (Chordata-Tunicata) Contains Heparin inside Basophil-like Cells and a Unique Sulfated Galactoglucan in the Plasma

The hemolymph of ascidians (Chordata-Tunicata) contains different types of hemocytes embedded in a liquid plasma. In the present study, heparin and a sulfated heteropolysaccharide were purified from the hemolymph of the ascidian Styela plicata. The heteropolysaccharide occurs free in the plasma, is composed of glucose ( approximately 60%) and galactose ( approximately 40%), and is highly sulfated. Heparin, on the other hand, occurs in the hemocytes, and high performance liquid chromatography of the products formed by degradation with specific lyases revealed that it is composed mainly by the disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4)) (39.7%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(6SO(4)) (38.2%). Small amounts of the 3-O-sulfated disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4)) (9.8%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4))(6SO(4)) (3.8%) were also detected. These 3-O-sulfated disaccharides were demonstrated to be essential for the binding of the hemocyte heparin to antithrombin III. Electron microscopy techniques were used to characterize the ultrastructure of the hemocytes and to localize heparin and histamine in these cells. At least five cell types were recognized and classified as univacuolated and multivacuolated cells, amebocytes, hemoblasts, and granulocytes. Immunocytochemistry showed that heparin and histamine co-localize in intracellular granules of only one type of hemocyte, the granulocyte. These results show for the first time that in ascidians, a sulfated galactoglucan circulates free in the plasma, and heparin occurs as an intracellular product of a circulating basophil-like cell.

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Various media were tested for in vitro germination of pollen grains of radish and Brassica campestris. The basal medium contained 50 mg·liter-1 H3BO3, 100 mg·liter-1 CaCl2 and the pH was adjusted to pH 5.8. Species of pollen grains tested were : radish (Raphanus sativus L.) 'Harumaki Minowase', 'Ryujin Miura', 'Motohashikei Taibyou Minowase', and four of Brassica campestris L. 'Hiroshimana' and 'Santousai' (non-heading chinese cabbage, pekinensis group), 'Mibuna' (japonica group), and Pak-choi 'Chingensai' (chinensis group). The results obtained were as follows ; 1. The basal medium containing 0.43M sucrose yielded the highest germination rate of radish pollen compared to that at 0.29 or 0.58M sucrose. 2. Among the media adjusted between pH 5.8a12.0, pH 9.0 gave the best pollen germination. 3. Germination rate was improved by using buffer solutions of pH 8.0 and 8.5, such as Taps, Tris, MES, boric acid or phosphoric acid buffer compared to distilled water. Taps and Tris buffers were most effective, followed by boric acid and barbital buffers. 4. Cholic acid, cetylmethyl ammonium bromide and sodium lauryl sulfate promoted pollen germination of radish. 5. Pollen grains of mother plants of the same age grown under 10a25°C during MayaJune, and OctoberaDecember had the best germination rate, whereas those obtained between JulyaSeptember had the poorest rate.

Cloning, characterization and chromosomal localization of a repeated sequence in Crypthecodinium cohnii, a marine dinoflagellate.

Genomic DNA of Crypthecodinium cohnii has been extracted in the presence of cetylmethylammonium bromide and hydrolysed by 13 restriction enzymes. No typical ladder-like pattern or isolated band of satellite sequences were found with any of these enzymes. A "mini" genomic DNA library had been made and screened by reverse hybridization to isolate highly repeated sequences. Seven such DNA fragments were sequenced. The copy number of one of them (Cc18), 226 bp long, was estimated at around 25,000, representing 0.06% of the total genome. Cc18 was found to be included in a higher fragment of 3.0 kb by Southern blot analysis after cleavage by PstI. This higher molecular weight fragment could be composed either of tandemly repeated Cc18 sequences, or by only one or a very low copy number of Cc18. In this latter case, these fragments, also repeated 25,000 times would represent 1 to 2% of the total genome. Genomic localization of Cc18 by in situ hybridization on squashed C. cohnii cells showed that it was widely distributed on the different chromosomes. All the chromosomes observed displayed Cc18 labeling, which appeared homogeneously distributed. The ability of Cc18 to be a specific molecular marker to distinguish sibling C. cohnii species is discussed.

Acceleration of bacterial glutamic decarboxylase and glutaminase by cetyltrimethylammonium bromide.

Acceleration of bacterial glutamic decarboxylase and glutaminase by cetyltrimethylammonium bromide.