Journal articles on the topic 'Sol-Gel/Centrifugation'
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1
WICKSTRÖM, Claes, Cecilia CHRISTERSSON, Julia R. DAVIES, and Ingemar CARLSTEDT. "Macromolecular organization of saliva: identification of ‘insoluble’ MUC5B assemblies and non-mucin proteins in the gel phase." Biochemical Journal 351, no. 2 (October 10, 2000): 421–28. http://dx.doi.org/10.1042/bj3510421.
Abstract:
Stimulated human submandibular/sublingual (HSMSL) and whole saliva were separated into sol and gel phases and mucins were isolated by density-gradient centrifugation in CsCl/4M guanidinium chloride. MUC5B and MUC7 were identified using anti-peptide antisera raised against sequences within the MUC5B and MUC7 apoproteins respectively. MUC7 was found mainly in the sol phase of both HSMSL and whole saliva, but some MUC7 was consistently present in the gel phase, suggesting that this mucin may interact with the salivary gel matrix. In HSMSL saliva, MUC5B was found in the gel phase; however, most of the material was ‘insoluble’in guanidinium chloride and was only brought into solution by reduction. In whole saliva, the MUC5B mucin was present both in the sol and gel phases although some material was again ‘insoluble’. Rate-zonal centrifugation of whole saliva showed that MUC5B mucins in the sol phase were smaller than those in the gel phase, suggesting differences in oligomerization and/or degradation. Antibodies against IgA, secretory component, lysozyme and lactoferrin were used to study the distribution of non-gel-forming proteins in the different phases of saliva. The majority of these proteins was found in the sol phase of both HSMSL and whole saliva. However, a significant fraction was present in the gel phase of whole saliva, suggesting a post-secretory interaction with the salivary gel matrix. A monoclonal antibody against a parotid salivary agglutinin was used to show that this protein is present mainly in the gel phase of both whole saliva and parotid secretion.
2
DAVIES, Julia R., Naila SVITACHEVA, Louise LANNEFORS, Ragnhild KORNFÄLT, and Ingemar CARLSTEDT. "Identification of MUC5B, MUC5AC and small amounts of MUC2 mucins in cystic fibrosis airway secretions." Biochemical Journal 344, no. 2 (November 24, 1999): 321–30. http://dx.doi.org/10.1042/bj3440321.
Abstract:
To investigate the genetic identities of the mucins secreted in cystic fibrosis (CF) airways, sputum was collected from five individuals. Samples were separated into gel and sol phases by high-speed centrifugation and the gel phase was extracted in 6 M guanidinium chloride. The ‘insoluble’ residue remaining after extraction of the gel phase was brought into solution by reduction/alkylation. Density-gradient centrifugation in CsCl revealed polydisperse distributions of sialic acid-containing mucins in the gel phase, insoluble residue and sol phase fractions and the degree of variation between the different individuals was low. Antibodies recognizing MUC5AC and MUC5B identified these mucins in each of the fractions. MUC2, however, was present only as a component of the insoluble residue from the gel which accounted for less than 4% by mass of the total mucins. MUC5B and MUC5AC from the gel phase were large oligomeric species composed of disulphide-bond linked subunits and MUC5B was present as two populations with different charge densities which are likely to correspond to MUC5B ‘glycoforms’. The sol phase contained, in addition to MUC5AC and MUC5B, mainly smaller mucins which did not react with the antisera and which were probably degraded. MUC5AC appeared to be enriched in the sol, suggesting that this mucin may be more susceptible to proteolytic degradation than MUC5B. The mucins present in sputum remained broadly similar during acute exacerbation and following antibiotic treatment, although the relative amount of an acidic MUC5B glycoform was decreased during infection.
3
Thornton, D. J., J. K. Sheehan, H. Lindgren, and I. Carlstedt. "Mucus glycoproteins from cystic fibrotic sputum. Macromolecular properties and structural ‘architecture’." Biochemical Journal 276, no. 3 (June 15, 1991): 667–75. http://dx.doi.org/10.1042/bj2760667.
Abstract:
Mucus glycoproteins (mucins) were isolated from sputum of patients with cystic fibrosis (CF) after separation into sol and gel phases. The mucus gel was solubilized with gentle stirring in 6 M-guanidinium chloride supplemented with proteinase inhibitors, and purification of mucins was subsequently achieved by isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. Density-gradient centrifugation also revealed a heterogeneity of the macromolecules, the pattern of which varied between individuals, and mucins from the gel phase was pooled as ‘heavy’ and ‘light’ fractions. Gel chromatography on Sepharose CL-2B showed that the heavy fraction contained a larger proportion of smaller species than the ‘light’ fraction and that the gel phase mucins were much larger than those from the sol. An apparently homogeneous high-Mr mucin population from one individual contained approx. 70% (w/w) carbohydrate, the major sugars being N-acetylglucosamine (17.8%), N-acetylgalactosamine (6.7%), galactose (20.7%), fucose (13.2%) and sialic acid (11.4%). These mucins had an S020.w of 47 S, and an Mr of 15 x 10(6) -20 x 10(6), and rate-zonal centrifugation revealed a polydisperse size distribution [range (5-30) x 10(6)] with a weight-average Mr of 17 x 10(6). The whole mucins were visualized with electron microscopy as linear and apparently flexible threads, disperse in size. Reduction produced subunits which were included on Sepharose CL-2B, and subsequent trypsin digestion yielded high-Mr glycopeptides which were further retarded. The size distributions and fragmentation patterns of mucin from two other CF patients were the same, as studied by gel chromatography, rate-zonal centrifugation and electron microscopy. We conclude that CF mucins are heterogeneous in both size and buoyant density and that the various populations, though differing in buoyant density, share the same architecture and macromolecular properties and are, in this respect, similar to mucins from normal respiratory secretions [Thornton, Davies, Kraayenbrink, Richardson, Sheehan & Carlstedt (1990) Biochem. J. 265, 179-186] and human cervical mucus [Carlstedt & Sheehan (1989) SEB Symp. XLIII 289-316].
4
HOVENBERG, Hans W., Ingemar CARLSTEDT, and Julia R. DAVIES. "Mucus glycoproteins in bovine trachea: identification of the major mucin populations in respiratory secretions and investigation of their tissue origins." Biochemical Journal 321, no. 1 (January 1, 1997): 117–24. http://dx.doi.org/10.1042/bj3210117.
Abstract:
Bovine respiratory secretions were separated into gel and sol phases to allow the identification of the gel-forming mucins. Mucins were subsequently isolated from the surface epithelium and submucosal tissue to investigate the tissue origins of the species in the secretions. Density-gradient centrifugation revealed ‘high-density’ and ‘low-density’ mucins in the gel phase of the secretions. The ‘high-density’ mucins were large, composed of subunits joined by disulphide bonds and contained two highly glycosylated domains of apparently different lengths, whereas the ‘low-density’ mucins were smaller and monomeric. The sol also contained both ‘high-density’ and ‘low-density’ species. A ‘high-density’ mucin similar to that in the gel was isolated from the surface epithelium, suggesting that the goblet cells produce large, gel-forming mucins. A second ‘high-density’ species was released from the submucosal tissue after reduction/alkylation, indicating that large mucins from the submucosal glands may also be a component of the mucus gel. In addition, two small, ‘low-density’ mucins were obtained from the submucosal tissue. One species was associated with the gel phase but was also present in the sol, whereas the other was present only in the sol. Bovine respiratory-tract secretions thus comprise a complex mixture of large gel-forming mucins originating from the goblet cells and submucosal glands, and smaller ‘soluble’ species from the submucosal glands which may interact with the gel.
5
Alias, S. S., A. B. Ismail, and A. A. Mohamad. "Effect of pH on ZnO nanoparticle properties synthesized by sol–gel centrifugation." Journal of Alloys and Compounds 499, no. 2 (June 2010): 231–37. http://dx.doi.org/10.1016/j.jallcom.2010.03.174.
6
Davies, J. R., J. T. Gallagher, P. S. Richardson, J. K. Sheehan, and I. Carlstedt. "Mucins in cat airway secretions." Biochemical Journal 275, no. 3 (May 1, 1991): 663–69. http://dx.doi.org/10.1042/bj2750663.
Abstract:
Mucous secretions were obtained from cat tracheas that had received [3H]glucose and [35S]sulphate to radiolabel mucus glycoproteins biosynthetically. Samples were collected under resting (‘basal’) conditions as well as after pilocarpine stimulation and were separated into gel and sol phases by centrifugation. Macromolecules were partially purified by using gel chromatography on Sepharose CL-4B, and the species that were eluted with the void volume were then separated into two major populations with isopycnic density-gradient centrifugation in CsCl. The major component from the gel phase of pilocarpine-induced secretions had a buoyant density typical of mucins and was observed as linear and apparently flexible chains by electron microscopy. Reduction of disulphide bonds gave subunits that could be further cleaved by trypsin digestion into components of approximately the same size as the high-Mr glycopeptides obtained from other mucins after this treatment. In contrast, the dominant species in the gel phase of the ‘basal’ secretion had a significantly higher buoyant density than expected for mucins and was largely unaffected by reduction, as studied by gel chromatography. The macromolecules were fragmented by trypsin, suggesting that they contain a polypeptide backbone. This more dense component also predominated in the sol phase both from the ‘basal’ secretions and from the pilocarpine-released secretions. Digestion with DNAase, chondroitin ABC lyase or heparan sulphate lyase had no effect, which shows that this component is not DNA, a dermatan sulphate/chondroitin sulphate or a heparan sulphate proteoglycan. In contrast, endo-beta-galactosidase and keratanase caused some fragmentation, suggesting that the molecules contain some linkages of the poly-(N-acetyl-lactosamine) type, although the degradation was not as extensive as expected for keratan sulphate. Treatment with alkaline borohydride resulted in extensive fragmentation of the high-Mr glycopeptides from both components, indicating that the glycans were oligosaccharides that were probably O-linked. The monosaccharide compositions of both components were consistent with that expected for mucins. The data are in keeping with the major component from the pilocarpine-stimulated gel secretions being a mucus glycoprotein and the more dense component being a mucin-like molecule, possibly related to the keratanase-sensitive material isolated from canine trachea by Varsano, Basbaum, Forsberg, Borson, Caughey & Nadel [(1987) Exp. Lung Res. 13, 157-184].
7
Hu, Yu Long, Xiao Dong Zhang, Hong Fang Liu, and Xing Peng Guo. "High-Efficiency Preparation of N-Doped Titania with High Visible Light Photocatalytic Activity Using Composite N Precursor." Key Engineering Materials 645-646 (May 2015): 368–74. http://dx.doi.org/10.4028/www.scientific.net/kem.645-646.368.
Abstract:
N-doped TiO2 nanoparticle powders were prepared efficiently by the sol-gel method using triethylamine and ammonium hydroxide as composite N precursor. The as-prepared N-doped TiO2 precursor powders were calcined at 300°C in air for 3 h and subsequently annealed at 300°C in air for 2.5 h. The samples were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, and X-ray photoelectron spectroscopy. The visible light photocatalytic activities of as-prepared samples were evaluated by photodecomposition of methyl orange (MO). The results show that the as-prepared samples have high visible light photocatalytic activities. Triethylamine produces the N-species doped in TiO2 lattice responsible for the high visible light photocatalytic activity. Ammonium hydroxide makes the gel of the TiO2 nanoparticles nitrided by triethylamine gelate further and facilitates significantly the centrifugation of the gel. An annealing treatment can eliminate effectively the outer N species caused by ammonium hydroxide and the surface organic residues, improve effectively crystallinity, and retain the N species caused by triethylamine.
8
Pollert, E., O. Kaman, P. Veverka, M. Veverka, M. Maryško, K. Závěta, M. Kačenka, et al. "Core–shell La 1− x Sr x MnO 3 nanoparticles as colloidal mediators for magnetic fluid hyperthermia." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 368, no. 1927 (September 28, 2010): 4389–405. http://dx.doi.org/10.1098/rsta.2010.0123.
Abstract:
Core–shell nanoparticles consisting of La 0.75 Sr 0.25 MnO 3 cores covered by silica were synthesized by a procedure consisting of several steps, including the sol–gel method in the presence of citric acid and ethylene glycol, thermal and mechanical treatment, encapsulation employing tetraethoxysilane and final separation by centrifugation in order to get the required size fraction. Morphological studies revealed well-separated particles that form a stable water suspension. Magnetic studies include magnetization measurements and investigation of the ferromagnetic–superparamagnetic–paramagnetic transition. Magnetic heating experiments in ‘calorimetric mode’ were used to determine the heating efficiency of the particles in water suspension and further employed for biological studies of extracellular and intracellular effects analysed by tests of viability.
9
Hu, Xufeng, Han Sun, Xiaopeng Zhao, and Jianbo Yin. "Enhanced Electrorheological Polishing Efficiency of Alumina-Doped Titanium Dioxide Particles." Materials 16, no. 6 (March 15, 2023): 2347. http://dx.doi.org/10.3390/ma16062347.
Abstract:
Electrorheological (ER) polishing is a novel polishing technology having flexible and tunable characteristics. At present, ER polishing uses ER particles to drive abrasive particles to polish the material surface. Under the action of high-speed centrifugation, the abrasive particles are easily separated from ER particles due to their significantly different ER effect, and this can easily cause the degradation of polishing ability. In this work, alumina-doped titanium dioxide ER polishing particles were developed via a sol-gel method. As a classical abrasive, alumina has higher hardness and can improve the ER effect of titanium dioxide by doping. Thus, alumina-doped titanium dioxide particles simultaneously possess high ER effect and high hardness. No phase separation appears in the polishing process and the result shows that alumina-doped titanium dioxide has a good polishing efficiency for materials with Mohs hardness of 3 and below.
10
Rembeza, E. S., T. V. Svistova, N. N. Kosheleva, D. S. Permyakov, M. V. Grechkina, T. G. Menshikova, and S. A. Romasev. "Synthesis and Electrophysical Properties of Copper Oxide Films for Gas Sensors." Nano- i Mikrosistemnaya Tehnika 25, no. 2 (April 21, 2023): 61–68. http://dx.doi.org/10.17587/nmst.25.61-68.
Abstract:
Thin films of copper oxide were fabricated by sol-gel method. For the preparation of CuO thin films, a sol-gel method based on copper acetate (Cu(CH3COO)2•H2O), isopropyl alcohol (C3H8O) and diethylamine ((CH3CH2 )2NH) was used. The film was applied by centrifugation at a speed of 1500 rpm for 75 seconds. The films were applied in 2, 4, 8 layers with drying between layers for 10 minutes at 250 °C. The thermal probe method was used to determine the p-type of conductivity of the films. The films were annealed at temperatures of 300, 400, 500, 600 °C. By method of X-ray phase analysis, it was found that the main phase in the films is CuO. On films without additional annealing, a single reflex corresponding to CuO (110) 31.7° is observed. After annealing the films at 400 and 500 °C, crystallization occurs and reflexes manifest: (110) by 31.7°, (–111) by 35.5°, (111) by 38.8°, corresponding to CuO. It was found that with an increase in the annealing temperature, the grain size decreases, which indicates the crystallization of the film and contributes to the improvement of gas-sensitive properties. The transparency of the films in the visible range has values T = 30—67 %. The width of the gap is estimated to be 1.9 eV. According to AFM data, the films have a fine-grained structure and with an increase in the annealing temperature from 300 °C to 400 °C, the size of the roughness decreases. The films have high gas sensitivity values (resistance change of 30 %) and low temperature values of maximum gas sensitivity (180—190) °C to ethanol, acetone, ammonia vapors in the air.
11
Ratirotjanakul, Waranya, Tanapon Sioloetwong, Teeraporn Suteewong, and Pramuan Tangboriboonrat. "Green Synthesis of AgNPs Coated Mesoporous Silica Nanoparticles Using Tyrosine as Reducing/Stabilising Agent." Materials Science Forum 928 (August 2018): 89–93. http://dx.doi.org/10.4028/www.scientific.net/msf.928.89.
Abstract:
A novel, simple and environmental friendly approach to fabricate silver nanoparticles (AgNPs) on mesoporous silica nanoparticles (MSNs) using tyrosine (Tyr) as biological reducing agent was developed. The functionalization of Tyr with MSNs (Tyr-MSNs) (150 nm in length) by the sol-gel process was confirmed by the characteristic peaks of amino, carboxyl and silanol groups appeared in FTIR spectrum and the change of the zeta potential from 0 mV at pH 2 to-60 mV at pH 12. Then, AgNPs were formed on the surface of Tyr-MSNs (Tyr-MSN@AgNPs) via only reducibility from phenolic group of Tyr and catalytic activity from base at room temperature. TEM images and UV-Visible absorption band at 420 nm supported the obtained AgNPs (18 nm at pH 11) were tightly bound to Tyr-MSNs even after centrifugation at high speed. These Tyr-MSN@AgNPs would be potentially used as drug carrier in biomedical applications.
12
Cui, Suihan, Qingdong Ruan, Cuiqing Jiang, Tijun Li, Zheng Jin, Ricky K. Y. Fu, Xiubo Tian, Paul K. Chu, Daining Fang, and Zhongzhen Wu. "Pre-lithiated Li(NixMnyCoz)O2 nanoparticles with a double-layer lithium structure." Functional Materials Letters 13, no. 04 (April 15, 2020): 2050020. http://dx.doi.org/10.1142/s1793604720500204.
Abstract:
Li(NixMnyCoz)O2 cathode materials (NMC) have advantages such as the good Li ion diffusivity, stable reversible capacity, and environmental compatibility in spite of a low actual capacity. Although a double-layer lithium structure can be generated by pre-lithiation, the thickness is very small and the capacity improvement is limited. In this work, a series of Li([Formula: see text][Formula: see text][Formula: see text])O2 nanoparticles are prepared by the sol–gel method and centrifugation and the pre-lithiation process are monitored by transmission electron microscope (TEM). A double lithium structure of about 10 nanometers thick is produced on the NMC materials with different sizes. With decreasing NMC particle size, the proportion of the double-layer lithium structure increases and reaches 48% for a particle diameter of 100[Formula: see text]nm. The results reveal a viable means to improve the capacity of NMC materials in charging and discharging.
13
Callone, Emanuela, Giovanni Carturan, Marco Ischia, and Adriana Sicurelli. "Nanometric oxides from molecular precursors in the presence of starch: Coatings of glass with these oxides in silica sols." Journal of Materials Research 21, no. 7 (July 1, 2006): 1726–37. http://dx.doi.org/10.1557/jmr.2006.0217.
Abstract:
Sn, Sn-Sb, Ti, Ce, Zr, Zn, In, In–Sn, and Fe oxides of nanometric size were obtained through the hydrolytic route, starting from molecular precursors in the presence of starch. Gels were treated with α-amylase to produce oxide suspensions and starch degradation. Solid oxide products resulted from reaction with H2O2, washing with H2O, and centrifugation of the suspensions. The nanometric size and morphology of crystallites were assessed by x-ray diffractometry, transmission electron microscopy, and, for SnO2, solid-state nuclear magnetic resonance. Product consolidation at 600 °C did not produce any noticeable increase in dimensions. Thermal analysis coupled with mass spectrometry of evolved gaseous species showed that glucoside residues remain chemically bonded to the nanoparticles, thus explaining the effective stabilization of crystallite dimensions. Aqueous suspensions of nanopowders were mixed with a silicon tetra-ethoxide ethanol solution and subjected to an ordinary sol-gel process. The resulting suspensions were used to obtain stable and homogeneous coatings on glass sheets.
14
Garzón-Agudelo, P. A., and J. Bautista-Ruiz. "Effect of layer thickness on anticorrosive performance of 316L steel coated with bismuth-titanium films." Journal of Physics: Conference Series 2139, no. 1 (December 1, 2021): 012014. http://dx.doi.org/10.1088/1742-6596/2139/1/012014.
Abstract:
Abstract Bismuth and titanium are elements with remarkable properties and applications in technological developments and in the field of biomedical engineering. The sol-gel method was used to form a bismuth-titanium system, which allowed to establish if it was possible to obtain films with anticorrosive properties on 316L stainless steel. The anticorrosive response was evaluated by means of Tafel curves, defining the parameters to obtain thin and functional films with good tribological properties. The coatings were obtained by the spin coating technique, varying the spin speeds from 3000 rpm to 5000 rpm with monolayer and bilayer systems. More positive values of corrosion potential were obtained when the steel is coated by the films, which implies a lower propensity to corrosion in saline medium, lower corrosion rates and higher potentials are reported for films with higher titanium content, likewise, better efficiency of the films with respect to the uncoated substrate is presented, the higher the titanium content and a strong influence between the calculated efficiencies and the centrifugation speeds is not observed.
15
Redha, Latrous Ahmed, Touafek Naima, and Mahamdi Ramdane. "Elaboration by spin coating and characterization of CZTS films." All Sciences Abstracts 1, no. 1 (April 20, 2023): 4. http://dx.doi.org/10.59287/as-abstracts.533.
Abstract:
Thin films of Cu2ZnSnS4 (CZTS) were deposited by the sol-gel spin coating method from a non-aqueous solution containing different molarities of precursors, cupric chloride CuCl2 (2H2O) (2M), zinc chloride ZnCl2 (1M), stannic chloride SnCl2 (2H2O) (1M) and thiourea SC(NH2)2 (8M) dissolved in different volumes of solvents, methanol CH3OH and deionized water. A light-yellow solution was formed by thermal centrifugation at adjustable speeds for several minutes. Characterizations were carried out after deposition, drying and thermal annealing of these films. XRD spectra showed the formation of several peaks with one peak corresponding to the (112) directions illustrating the presence of kesterite. The gap energy was deduced 1.87 eV from the transmittance obtained by UV-Visible-NIR. The percentages of the different CZTS constituents by SEM were recorded. The thicknesses of the films obtained by profilometer are between 0.6 μm and 2 μm. The theoretical study and the results of the characterization can contribute to the realization of a CZTS active layer of a photovoltaic cell.
16
Xekoukoulotakis, N. P., D. Mantzavinos, R. Dillert, and D. Bahnemann. "Synthesis and photocatalytic activity of boron-doped TiO2 in aqueous suspensions under UV-A irradiation." Water Science and Technology 61, no. 10 (May 1, 2010): 2501–6. http://dx.doi.org/10.2166/wst.2010.150.
Abstract:
Boron-doped TiO2 photocatalysts were synthesized employing a sol-gel method. Boric acid was used as the boron source and titanium tetra-isopropoxide as the TiO2 precursor, both dissolved in isopropanol. Nominal boron to titanium atomic ratios were in the range 0 to 4%. After the hydrolysis step, two different procedures for the recovery of TiO2 were followed, based on either centrifugation of the resulting reaction mixture or evaporation of the solvent under reduced pressure, both followed by a subsequent calcination step performed at 400 or 500°C. The photocatalytic efficiency of the synthesized photocatalysts was assessed by measuring the photocatalytic mineralization of dichloroacetic acid in aqueous suspensions under UV-A irradiation and it was compared to the corresponding efficiency of the commercial Degussa P 25 TiO2. Photocatalytic efficiency of the synthesized catalysts was higher for the boron-doped TiO2 synthesized at 2% boron to titanium nominal atomic ratio, centrifuged after the hydrolysis step followed by calcinations at 400°C. However, all photocatalysts synthesized in this work showed lower photocatalytic activity than Degussa P 25 TiO2, thus highlighting the need of further improvements of the proposed method.
17
Kobayashi, Yoshio, Hikaru Morimoto, Tomohiko Nakagawa, Yohsuke Kubota, Kohsuke Gonda, and Noriaki Ohuchi. "Preparation of Gd Complex-Immobilized Silica Particles and Their Application to MRI." ISRN Nanotechnology 2013 (April 10, 2013): 1–6. http://dx.doi.org/10.1155/2013/908614.
Abstract:
A preparation method for Gd-ethylenediaminetetraacetic acid disodium salt dihydrate (ETDA) complex-immobilized silica particles (Gd-EDTA/SiO2) is proposed. Preparation of spherical silica particles was performed by a sol-gel method at 35°C using 0.2 M tetraethylorthosilicate, 25 M H2O, and 0.01 M NaOH in ethanol, which produced silica particles with an average size of nm. Immobilization of Gd-EDTA on the silica particles was conducted at 35°C by introducing amino groups on the silica particles with (3-aminopropyl)trimethoxysilane at pH 3 (NH2/SiO2) and then making Gd-EDTA act on the NH2/SiO2 particles at pH 5. The as-prepared Gd-EDTA/SiO2 particle colloid solution was concentrated up to a Gd concentration of 0.347 mM by centrifugation. The sphere structure of Gd-EDTA/SiO2 particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated Gd-EDTA/SiO2 colloid solution revealed good MRI properties. A relaxivity value for T1-weighted imaging was as high as 5.15 mM−1 s−1, that was comparable to that for a commercial Gd complex contrast agent.
18
Kobayashi, Yoshio, Tetsuya Ayame, Kyosuke Shibuya, Tomohiko Nakagawa, Yohsuke Kubota, Kohsuke Gonda, and Noriaki Ohuchi. "Stabilization of silica-coated silver iodide nanoparticles by ethanol-washing." Pigment & Resin Technology 45, no. 2 (March 7, 2016): 99–105. http://dx.doi.org/10.1108/prt-10-2014-0083.
Abstract:
Purpose – This paper aims to propose a simple method for stabilizing silica-coated silver iodide (AgI/SiO2) core-shell particles, of which a colloid solution functions as an X-ray contrast agent. Design/methodology/approach – A colloid solution of AgI nanoparticles was prepared by mixing silver perchlorate and potassium iodide in water. The AgI/SiO2 nanoparticles were fabricated by a sol-gel method using NaOH, H2O and tetraethylorthosilicate in ethanol in the presence of AgI nanoparticles surface-modified with 3-mercaptopropyltrimethoxysilane. Findings – The silica shells of AgI/SiO2 particles were dissolved near the AgI nanoparticle surface, when they were washed by a process composed of centrifugation, removal of supernatant with decantation, addition of water as a washing solution and a shake with a vortex mixer. In contrast, the shells were not damaged by using ethanol as the washing solution, i.e. ethanol-washing. An X-ray photoelectron spectroscopy spectrum of the silica was changed after the ethanol-washing, which indicated that the ethanol-washing had an effect on the chemical bonds in silica. The effect also acted on the silica shells of AgI/SiO2 particles, which did not damage the core-shell structure, i.e. controlled the dissolution of shell. Originality/value – The paper demonstrates that the ethanol-washing is quite useful for stabilizing the core-shell structure composed of the silica shells.
19
Cheng, Gang, Hong Chen, Kai Wang, Jinxing Gao, Xiao Li, Hui Dong, and Shuyan Liu. "Biphasic Calcium Phosphate/Chitosan/Polyacrylonitrile/Polylactic Acid-Glycolic Acid (PLGA) Nanocomposite Stent for Repair and Osteogenesis of Oral Alveolar Bone Defect." Science of Advanced Materials 13, no. 7 (July 1, 2021): 1324–34. http://dx.doi.org/10.1166/sam.2021.4039.
Abstract:
ABSTRACTThe ability of sol-gel micro-nano biphasic calcium stent to repair oral alveolar bone defects was investigated in this study, and its osteogenesis performance was also analyzed. Biphasic calcium phosphate (BCP) was synthesized by wet method, which was combined with chitosan (CS), polyacrylonitrile (PAN), and polylactic acid-glycolic acid (PLGA). Then, the BCP/CS/PAN/PLGA nanocomposite stent was prepared by vacuum freeze-drying technology. The micro-nano composite stent was combined with the bone morphogenetic protein-2 (BMP-2) gene, so as to obtain the sol-gel micro-nano biphasic calcium BMP-2/BCP/CS/PAN/PLGA composite stent. Besides, the composite stent should be measured in terms of compressive strength, porosity, structure, and morphological features. The healthy female rhesus monkeys were taken as the research animals, and the iliac bone marrow was extracted by puncture. The mesenchymal stem cells (MSCs) were obtained by density gradient centrifugation, and their osteogenic differentiation ability was observed. The MSCs were cultured in vitro with BMP-2/BCP/CS/PAN/PLGA composite stent, methylthiazolyldiphenyl-tetrazolium bromide (MTT) was applied to detect cell adhesion and proliferation, and the alkaline phosphatase (ALP) activity was employed to analyze its osteogenic properties on stent materials. In addition, the expression of BMP-2 was detected by Western blot. The alveolar bone defect models were established and divided into group A (MSCs + BMP-2/BCP/CS/PAN/PLGA), group B (BMP-2/BCP/CS/PAN/PLGA), group C (BCP/CS/PAN/PLG), and group D (control group, reposition of gingival flap and suture) according to different implant materials. The changes of bone defect area in different groups were detected by gross examinations and X-ray, so that the new bone density was analyzed. The results showed that the BCP/CS/PAN/PLGA composite stent exhibited a porous structure combining multiple pores/small pores, with an average pore diameter (PD) of 400–500 µm, maximum compressive strength of 6.02 Mpa, and porosity of 86.82%. MSCs differentiated into osteoblasts under osteogenic induction conditioned medium, and the optical density (OD) of CS + MSCs/BMP-2/BCP/CS/PAN/PLGA cells was greater in contrast to that of MSCs/BMP-2/BCP/CS/PAN/PLGA cells on the 1st and 7th day of culture, showing a statistical difference (P < 0.05). The gross examination and X-ray of bone defect area in group A showed that its bone structure and density were very close to those of normal bone (all materials were absorbed, and newly formed bone cells were active); the CT value of alveolar bone in groups A, B, C, and D was 1,092.45± 15.87 g/cm3, 932.26± 16.75 g/cm3, 859.51 ±17.86 g/cm3, and 787.96± 16.54 g/cm3, respectively. There was no marked difference in CT values between group A and normal alveolar bone (P > 0.05), while the CT value of alveolar bone in group A was higher obviously than the value of groups C and D (P < 0.05). It indicated that the composite stent based on sol–gel micro-nano biphasic calcium BMP-2/BCP/CS/PAN/PLGA could promote the repair of oral alveolar bone defect and its osteogenesis, thereby providing a reference for the oral clinical treatment of periodontal bone defects.
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Аймбетова, И. О., Э. О. Аймбетова, О. С. Байгенженов, Д. Берди, and Б. Умиров. "DEVELOPMENT OF A V2O5 THIN FILM DEPOSITION TECHNIQUE." Вестник ГГНТУ. Технические науки, no. 4(30) (December 22, 2022): 38–48. http://dx.doi.org/10.34708/gstou.2022.47.67.005.
Abstract:
На основании технологического и экономического анализа самым оптимальным и технологически приемлемым методом получения термохромных композиций является легирование пленок фазопереходными материалами, позволяющих управлять основными параметрами энергосбережения и других термосвойств, с последующим нанесением на стеклянные и/или другие подложки. Исследован рост кристаллитов поликристаллических пленок, изготовленных путем одновременной вариации толщины напыленной пленки оксида ванадия и времени ее термообработки при различных температурах. Исследование структуры пленки осуществлено рентгеновским микрозондовым анализатором. Для определения оптимального ведения процесса осаждения тонких пленок оксида ванадия на поверхность стеклянной подложки были исследованы методы магнетронного осаждения, метод центрифугирования, нанесение опусканием в раствор с термохромным материалом. При spin-coating осаждении планарных покрытий тонких пленок V2O5 использована золь-гель техника. На основании проведенных исследований выявлено, что эффективные термохромные и электрохромные свойства демонстрируются пленками, поперечный размер которых менее 2 микрометров. Термическая обработка при температуре 400 позволяет кальцинацию и отжиг вещества. Выявлено, что при совместном послойном осаждении пентаоксида ванадия с оксидами переходных металлов на стеклянную подложку повышение/понижение температуры влияет на индуцированные изменения химических связей в комплексе и/ или координации лигандов вокруг иона переходного металла, который способствует снижению фотокаталической активности, порция ультрафиолетового света, поступающая на поверхность нанокатализатора, полностью поглощается каркасом слоя V2O5. Based on technological and economic analysis, the most optimal and technologically acceptable method for obtaining thermochromic compositions is the alloying of films of phase-transition materials that allow controlling the main parameters of energy saving and other thermal properties, followed by application to glass and/or other substrates. The growth of crystallites of polycrystalline films made by simultaneous variation of the thickness of the sprayed vanadium oxide film and the time of its heat treatment at different temperatures is investigated. The study of the film structure was carried out by an X-ray microprobe analyzer. In order to determine the optimal conduct of the process of deposition methods of thin films of vanadium oxide on the surface of a glass substrate, magnetron deposition methods, the method of centrifugation deposition by lowering into a solution with thermochromic material were investigated. During spin-coating deposition of planar coatings of V2O5 thin films, sol-gel technique was used. Based on the conducted studies, it was revealed that effective thermochromic and electrochromic properties are demonstrated by films whose transverse size is less than 2 micrometers. Heat treatment at a temperature of 400 allows calcination and annealing of the substance. It was revealed that during the joint layer-by-layer deposition of vanadium pentoxide with transition metal oxides on a glass substrate, an increase/decrease in temperature affects induced changes in chemical bonds in the complex and/or coordination of ligands around the transition metal ion, which contributes to a decrease in photocatalytic activity, a portion of ultraviolet light entering the surface of the nanocatalyst is completely absorbed by the framework of the V2O5 layer.
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Zhang, Raymond, Timofey Averianov, and Ekaterina Pomerantseva. "Assembly of Two-Dimensional δ-V2O5-Ti3C2Tx Heterostructure Electrodes for Li-Ion Batteries." ECS Meeting Abstracts MA2022-02, no. 2 (October 9, 2022): 150. http://dx.doi.org/10.1149/ma2022-022150mtgabs.
Abstract:
The bilayered phase of vanadium oxide (δ-V2O5∙nH2O or BVO) synthesized via sol-gel synthesis method is an attractive candidate to be used as a cathode material for Li-ion batteries (LIBs) due to its expanded interlayer spacing, and high theoretical capacity. However, poor electrical conductivity and rapid capacity fade present challenges for achieving high-rate performance and good cycle life during cycling in LIBs. A viable solution to mitigating these drawbacks is to fabricate two-dimensional (2D) heterostructures comprised of vanadium oxide and an additional selected 2D material. Titanium carbide (Ti3C2Tx) MXenes are particularly of interest for their high electronic conductivity (103 S cm-1) and well developed delamination protocols. Herein, we present a wet-based approach for assembling BVO and MXene nanoflakes into 2D heterostructures in suspension. In this study, we first demonstrate a simple liquid phase exfoliation technique utilizing probe ultrasonication to exfoliate bulk -LixV2O5·nH2O (LVO). Previous experiments from our group showed the exfoliation technique in n-methyl-2-pyrrolidone, an organic solvent that is toxic, flammable, and resulted in low yield during exfoliation. Here, for the first time, we have successfully performed exfoliation of LVO in aqueous media and obtained few layered nanoflakes with high yield after centrifugation. Despite the partial solubility of vanadium oxide in water, these nanoflakes suspended in aqueous media maintained chemical stability and readily assembled into a free-standing film using vacuum filtration. The LVO nanoflake films have a two-dimensional (2D) layered morphology as confirmed by SEM and maintain the bilayered structure as confirmed by XRD. Due to the hydrated nature of LVO, we also highlight the importance of controlling interlayer water content with vacuum drying for achieving better cycling stability. The comparison of a 105°C and 200°C vacuum drying temperature and corresponding interlayer water content was carried out using XRD, TGA, and Raman spectroscopy characterization methods. The 200°C vacuum dried LVO nanoflake cathode achieved an initial ion storage capacity of 212 mAh g-1 which was 32.5% higher than the sample dried at 105°C. In addition, galvanostatic cycling experiments conducted for the 200°C vacuum dried LVO nanoflake cathode show there were significant improvements in capacity retention by ~35%, compared to the 105°C dried sample, after 100 cycles at a current density of 20 mA g-1. Subsequently, dispersions of LVO and Ti3C2Tx flakes in water were combined in different weight ratios of 9:1, 4:1, and 1:1 LVO to Ti3C2Tx. The heterostructure electrostatic assembly was facilitated by the introduction of a cationic species into the mixed suspensions. Resistivity measurements showed that heterostructure films achieved electronic conductivities as high as ~105 higher than pristine LVO. Through electrochemical testing, the 9:1 heterostructure cathodes delivered the highest ion storage capacity of 167 mAh g-1. At the cost of lower capacity (125.3 mAh g-1), the 4:1 heterostructures maintain a superior capacity retention of ~96% after 10 cycles. Furthermore, rate capability experiments for the 9:1 heterostructure cathodes demonstrate that the addition of 10 wt % Ti3C2Tx to LVO enables greater tolerance to high current densities with a capacity retention of ~90% after cycling through increasing current densities. In this work we also show that increased capacities can be acquired upon the extension of the potential window below 2V covering where Ti3C2Tx exhibits redox activity. These results demonstrate an environmentally friendly and safe approach to obtaining 2D LVO nanoflakes and offers pathways to constructing novel vanadium oxide based 2D heterostructures for improving electrochemical performance in energy storage devices.
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Kostryukov, Victor F., Irina Y. Mittova, Boris V. Sladkopevtsev, Anna S. Parshina, and Dar’ya S. Balasheva. "Роль BiPO4, вводимого через газовую фазу, в процессе создания тонких пленок на поверхности InP." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 21, no. 2 (June 14, 2019): 215–24. http://dx.doi.org/10.17308/kcmf.2019.21/759.
Abstract:
Исследованием термооксидирования фосфида индия под воздействием фосфата висмута, вводимого через газовую фазу, установлено ускоряющее воздействие фосфата висмута на процесс формирования пленок. Величина ускорения составляет от 1.5 до 2 раз, и максимальный прирост пленки достигается в первые 10 мин оксидирования. Определяющим процессом является образование фосфата индия за счет вторичного взаимодействия оксидных форм компонентов подложки, лимитируемое диффузией оксидов в твердой фазе. Методами инфракрасной спектроскопии, локального рентгеноспектрального микроанализа и рентгенофазового анализа установлен состав пленок на поверхности InP, основными компонентами которого являются различные фосфаты индия
REFERENCES
Wager J. F., Wilmsen C. W. Thermal oxidation of InP. Appl. Phys., 1980, v. 51(1), pp. 812–814. https://doi.org/10.1063/1.327302
Yamaguchi M., Ando K. Thermal oxidation of InP and properties of oxide fi lm. Appl. Phys., 1980, v. 5(9), pp. 5007–5012. https://doi.org/10.1063/1.3283803. Mittova I. Ya., Borzakova G. V., Terekhov V. A., Mittov O. N, Pshestanchik V. R., Kashkarov V. M. Growth of own oxide layers on indium phosphide. Izvestija AN SSSR. Serija Neorganicheskie Materialy [News of the Academy of Sciences of the USSR. Series Inorganic Materials], 1991, v. 27(10), pp. 2047–2051. (in Russ.)
Mittova I. Ya., Borzakova G. V., Terekhov V. A., Mittov O. N, Pshestanchik V. R., Kashkarov V. M. Growth of own oxide layers on indium phosphide. Izvestija AN SSSR. Serija Neorganicheskie Materialy [News of the Academy of Sciences of the USSR. Series Inorganic Materials], 1991, v. 27(10), pp. 2047–2051. (in Russ.)
Minaychev V. Ye. Naneseniye plonok v vakuume. [Film deposition in vacuum]. Moscow, Vyssh. Shkola Publ., 1989, 130 p. (in Russ.)
Nikitin M. M. Tekhnologiya i oborudovaniye vakuumnogo napyleniya [Technology and equipment for vacuum deposition]. Moscow, Metallurgiya Publ., 1992, 112 p. (in Russ.)
Veselov A. A., Veselov A. G., Vysotsky S. L., Dzhumaliyev A. S., Filimonov Yu. A. Magnetic properties of thermally deposited Fe/GaAs (100) thin fi lms. J Technical Physics, 2002, v. 47(8), pp. 1067–1070. https://doi.org/10.1134/1.1501694
Danilin B. S. Magnetronnyye raspylitel’nyye sistemy [Magnetron Spray Systems]. Moscow, Radio i svyaz’ Publ., 1982, 72 p.
Pulver D., Wilmsen C.W. Thermal oxides of In0.5Ga0.5P and In0.5Al0.5P. Vac. Sci. Technol. B., 2001, v. 19(1), pp. 207–214. https://doi.org/10.1116/1.1342008
Punkkinen M. P. J., Laukkanen P., Lеng J., Kuzmin M., Tuominen M., Tuominen V., Dahl J., Pessa M., Guina M., Kokko K., Sadowski J., Johansson B., Väyrynen I. J., Vitos L. Oxidized In-containing III–V(100) surfaces: Formation of crystalline oxide fi lms and semiconductor-oxide interfaces. Physical review, 2011, v. 83(19), pp. 195–329. https://doi.org/10.1103/Phys-RevB.83.195329
Sladkopevtsev B. V., Tomina E. V., Mittova I. Ya., Dontsov A. I., Pelipenko D. I. On the thermal oxidation of VxOy–InP heterostructures formed by the centrifugation of vanadium (V) oxide gel. Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques, 2016, v. 10(2), pp. 335–340. https://doi.org/10.1134/S102745101602018X
Ningyi Y. Comparison of VO2 thin fi lms prepared by inorganic sol-gel and IBED methods. Appl. Phys. A., 2003, v. 78. pp. 777–780. https://doi.org/10.1007/s00339-002-2057-5
Herman M. A., Sitter H. Epitaxy: Fundamentals and Current Status. Heidelberg, Springer Science & Business Media, 2013, 382 p.
Manijeh R. The MOCVD Challenge: A survey of GaInAsP–InP and GaInAsP–GaAs for photonic and electronic device applications. Boca Raton, CRC Press, 2010, 799 p. https://doi.org/10.1201/9781439807002
Mittova Ya. Multichannel reactions in chemostimulated oxidation of semiconductors – transit, conjugation, catalysis. Vestnik VGU. Serija: Himija, biologija [Bulletin of the VSU. Series: Chemistry, Biology], 2000, 2, pp. 5–12. (in Russ.)
Mittova Ya. Infl uence of the physicochemical nature of chemical stimulators and the way they are introduced into a system on the mechanism of the thermal oxidation of GaAs and InP. Inorganic Materials, 2014, V. 50(9), pp. 874–881. https://doi.org/10.1134/S0020168514090088.
Brauer G. A. Rukovodstvo po neorganicheskomu sintezu [Inorganic Synthesis Guide]. Moscow, Khimiya Publ., 1985, 360 с. (in Russ.)
Nakamoto K. Infared and Raman Spectra of Inorganic and Coordination Compounds. New York, John Wiley & Sons Ltd, 1986, 335 p.
Atlas IK-spektrov fosfatov [Atlas IR spectra of phosphates]. by R.YA. Mel’nikovoy. Moscow, Nauka Publ., 1985, 235 p. (in Russ.)
Brandon D., Kaplan W. Microstructural Characterization of Materials. 2nd Edition, John Wiley & Sons Ltd, 2008, 536 p. https://doi.org/10.1002/9780470727133
International Center for Diffraction Data. 21. X-ray diffraction date cards, ASTM.
X-ray diffraction date cards, ASTM.
Kazenas B.K. Termodinamika ispareniya dvoynykh oksidov. [Thermodynamics of double oxide evaporation]. Мoscow, Nauka Publ., 2004, 551 p. (in Russ.)
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Jiang, Hang, Hengxing Yu, Xin Guan, Weijie Jiang, Yunxing Li, Wei Liu, Cheng Yang, Jianzhong Jiang, Bernard P. Binks, and To Ngai. "Harnessing the Power of Nature: Monodisperse Pickering Emulsion Droplets and Yolk‐Shell Microcapsules Utilizing Bee Pollen Particles." Advanced Functional Materials, February 15, 2024. http://dx.doi.org/10.1002/adfm.202316510.
Abstract:
AbstractThe preparation of monodisperse Pickering emulsions currently can only be achieved using microfluidics or membrane emulsification, limiting its widespread applications in many fields. Here, by simply introducing naturally occurring pollen grains during mechanical emulsification, it becomes extremely feasible to fabricate uniform Pickering emulsions. The process of shearing and turbulence leads to a constant reduction in the size of the droplets of the dispersed phase. The robust exine of the pollen grains in the continuous phase enables them to retain their structural integrity during emulsification, resulting in the formation of a single pollen‐in‐water‐in‐oil structure. Meanwhile, the intrinsic monodispersity of the pollen grains allows for the resulting emulsions to be similarly uniform, and they can be easily collected through centrifugation. As a result, this novel methodology achieves the effective formulation of monodisperse Pickering emulsions in an unprecedented way. Furthermore, the utilization of sporopollenin exine capsules (SECs) as a replacement for pollen, in conjunction with sol–gel interfacial engineering, enables the attainment of “yolk‐shell” dual‐shell microcapsules. This approach not only effectively addresses the issue of cargo leakage in SECs but also imparts exceptional uniformity and stability to the microcapsules.
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Nikoorazm, Mohsen, Maryam Khanmoradi, and Masoumeh Sayadian. "Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation." Combinatorial Chemistry & High Throughput Screening 23 (November 11, 2020). http://dx.doi.org/10.2174/1386207323999201111192649.
Abstract:
Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.