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31.
Varghese N Shetye GS Bandyopadhyay D Gobalasingham N Seo J Wang JH Theiler B Luk YY 《Langmuir : the ACS journal of surfaces and colloids》2012,28(29):10797-10807
Single-chain surfactants usually emulsify and stabilize oily substances into droplets in an aqueous solution. Here, we report a coassembly system, in which single types of anionic or non-ionic surfactants emulsify a class of water-soluble nonamphiphilic organic salts with fused aromatic rings in aqueous solutions. The nonamphiphilic organic salts are in turn promoted to form droplets of water-based liquid crystals (chromonic liquid crystals) encapsulated by single-chain surfactants. The droplets, stabilized against coalescence by encapsulated in a layer (or layers) of single chain surfactants, are of both nonspherical tactoid (elongated ellipsoid with pointy ends) and spherical shapes. The tactoids have an average long axis of ~9 μm and a short axis of ~3.5 μm with the liquid crystal aligning parallel to the droplet surface. The spherical droplets are 5-10 μm in diameter and have the liquid crystal aligning perpendicular to the droplet surface and a point defect in the center. Cationic and zwitterionic surfactants studied in this work did not promote the organic salt to form droplets. These results illustrate the complex interplay of self-association and thermodynamic incompatibility of molecules in water, which can cause new assembly behavior, including potential formation of vesicles or other assemblies, from surfactants that usually form only micelles. These unprecedented tactoidal shaped droplets also provide potential for the fabrication of new soft organic microcapsules. 相似文献
32.
A method is developed for extraction of gold(III) (75–300 g) from hydrochloric acid solution with triphenylarsine oxide dissolved in toluene as extradant. Gold(III) is determined spectrophotometrically with stannous chloride. The extraction is quantitative from 1.5–1.9M hydrochloric acid with 0.25% triphenylarsine oxide and an equilibration period of 30s. The method permits separation of gold(III) from Cu(II), Pt(IV), Pd(II), Ni(II), Zn(II), Cd(II) and Hg(II) and its spectrophotometric determination in ayurvedic medicines. The recovery and relative standard deviation obtained are >99.0% and <1.0%. 相似文献
33.
Polyol Process Synthesis of Monodispersed FePt Nanoparticles 总被引:1,自引:0,他引:1
Liu C Wu X Klemmer T Shukla N Yang X Weller D Roy AG Tanase M Laughlin D 《The journal of physical chemistry. B》2004,108(20):6121-6123
Monodispersed FePt nanoparticles are synthesized by reduction of iron(II) acetylacetonate and platinum(II) acetylacetonate with 1,2-hexadecanediol as the reducing reagent in the polyol process. As-prepared FePt nanoparticles are chemically disordered with fcc phase. Transmission electron microscopy (TEM) images show a self-assembled particle array with an average particle size of 3 nm and a standard deviation about 10%. The transformation from chemically disordered fcc to chemically ordered L10 phase is achieved by annealing at 650 degrees C for 30 min in Ar atmosphere where the oxygen level is less than 1 ppm. Magnetic hysteresis measurements show a coercivity of 9.0 kOe at 293K, and 16.7 kOe at 5 K for the annealed FePt nanoparticles. 相似文献
34.
Devdutt Chaturvedi Nisha Mishra Virendra Mishra 《Monatshefte für Chemie / Chemical Monthly》2007,138(1):57-60
Summary. A novel Mitsunobu-based protocol was developed for the synthesis of carbamates from the corresponding alcohols using carbon dioxide and amines
in good to excellent yields. This protocol is mild, chemoselective, and efficient compared to other reported methods. 相似文献
35.
Poonia Nisha Lal Kashmiri Kumar Ashwani Kumar Anil Sahu Srikanta Baidya Anurag T. K. Kumar Rajnish 《Molecular diversity》2022,26(5):2375-2391
Molecular Diversity - Some urea-thiazole/benzothiazole hybrids with a triazole linker were synthesized via Cu(I)-catalysed click reaction. After successfully analysed by various spectral techniques... 相似文献
36.
Mario Pink Nisha Verma Albert W. Rettenmeier Simone Schmitz‐Spanke 《Electrophoresis》2010,31(4):593-598
Various CBB‐based methods for staining proteins separated by 2‐D gel electrophoresis were compared with regard to sensitivity and resolution. A modified Kang's CBB staining protocol, which we have modified, includes phosphoric acid in a concentration of 8% instead of the original 2%. This proved to be the best approach. Protein amounts as low as 2 ng and ∼2300 spots in the gel can be detected by employing this protocol. The modified procedure takes less time to carry out. Moreover, this practice is more sensitive and resolves more protein spots than most protocols reported to date and is compatible with subsequent mass spectrometric analysis. 相似文献
37.
38.
The Eupatorium odoratum leaf peroxidase exists as at least seven distinct isozymes (three cationic, three anionic, and one neutral). These isozymes
were identified and separated by preparative iso-electric focusing. Thermal stability, including the activation enthalpy (ΔH
*), free energy of inactivation (ΔG
*) and activation entropy (ΔS
*), and kinetic studies of two isozymes, one having a pI of 5.0 (E5) and another one having a pI of 7.0 (E7) with mol mass
of 43 and 50 kD, respectively, were studied in detail. Of the molecular weight of E5 and E7, 25 and 32% correspond to the
carbohydrate content of the isozymes. Optimal pH was in the acidic range of 3.6–3.8 for E5 and 3.8 for E7 with the oxidation
of ABTS. E7 and E5 showed activation energy for inactivation, 194.8 and 145.4 kJ/mol, respectively. Both the isozymes showed
distinct substrate specificity. The catalytic specificity constant for E5 and E7 were 112×105 and 124×105/s·M, respectively, when 2,2′-azino-bis-(3-ethylbenz-thiazoline-6 sulfonic acid) was used as the substrate. Maximum affinity (i.e., lowest K
m value) to H2O2 was shown by E5 and E7 along with Pyrogallol and was 0.02 and 0.05/s·M, respectively. 相似文献
39.
Maiti S Chatterji PR Nisha CK Manorama SV Aswal VK Goyal PS 《Journal of colloid and interface science》2001,240(2):630-635
Aggregation behavior in aqueous solution of a series of poly (ethylene glycol) (PEG)-based macromonomers with methacryloyl group as the only hydrophobic segment has been investigated using surface tension, steady-state and time-resolved fluorescence spectroscopy using pyrene as a probe, and small-angle neutron scattering techniques. The general formula of these macromonomers is CH2=C(CH3)–CO–O–Em–CH3, where E is the ethylene glycol unit and m=8 (ME8), 18 (ME18), 49 (ME49), and 120 (ME120). The results indicate that a macromonomer with 8 ethylene glycol units forms as an aggregate above a certain critical concentration, which can be defined as critical aggregation concentration. The observed high value of I1/I3 in pyrene emission spectra at the interface of these aggregates and the inability to scatter a neutron beam by these aggregates indicate that the hydrophobic cluster formed by this macromonomer is remarkably solvated. ME18 has a tendency to aggregate but others do not form any hydrophobic cluster. The homopolymerization behaviors of these macromonomers in an aqueous medium at 70°C are consistent with these possibi- lities. 相似文献
40.
Mohd. Imran Ansari Mohd. Kamil Hussain Nisha Yadav Puneet K. Gupta K. Hajela 《Tetrahedron letters》2012,53(16):2063-2065
A rapid and chemoselective method for the N-formylation of structurally diverse amines with formic acid using silica supported perchloric acid (HClO4–SiO2) at room temperature and under solvent-free conditions has been developed. The catalyst was found to be compatible with different functional groups and the formylation proceeded smoothly with amines bearing electron withdrawing as well as electron donating substituents. 相似文献