One-phase Method Research Articles

Mobility of B.C.T. Dental implants inserted by one and two-phase surgical method: An experimental study

Achievement of the osseointegration of dental implants is of crucial importance for their long-term survival. One of the factors that influence the osseointegration is a surgical method of implantation. The outcome of osseointegration can be evaluated on the basis of implant mobility in bone. The aim of this study was to investigate and compare the mobility of B.C.T. dental titanium implants inserted to experimental animals using an one- and two-phase method. The investigation was performed using a split-mouth design on nine dogs, male german shephards, average age of 3.5 years and average weight of 32 kg. Extractions of the third and fourth lower premolars were performed under intravenous (i.v.) anaesthesia with 5% ketamine chloride. Eight weeks after the extractions, the implants, diameter of 4.5 mm each, with four threads 13.7 mm long, were inserted. Eighteen implants were inserted one side of the jaw using a one-phase method, and another 18 implants were inserted contralaterally using a two-phase method. Three months after the implantation, the implant mobility was evaluated. Three measurements were performed with a Periotest device, and average values were calculated. The implant mobility was classified according to the Periotest scale in four groups of Periotest values (PTV) and compared. A total of 36 implants were inserted in 9 experimental dogs. The PTV ranged from -7.666 to + 50. According to the Periotest scale, 14 one-phase implants (78%) were classified into the 0 group of PTV, and 4 one-phase implants (22%) in the 3rd group. Thirteen two-phase implants (72%) were classified in the 0 group, and 5 implants in the 3rd group of Periotest scale. The difference in the average values of PTV between the two methods was 0.879 which was not statistically significant. This study showed that the method of implant insertion had no influence on the implant mobility, i.e. satisfactory osseointegration could be achieved by both methods. Further clinical parameters, as well as pathohistological and histomorphometric ones, have to be evaluated in order to assess better outcome of a particular method.

Synthesis and Microstructural Analysis of Benzylthiol-functionalized Au Nanocrystals

ABSTRACTWe report on the synthesis and microstructural and microanalytical analysis of dodecanethiol and benzylthiol-stabilized Au nanoparticles (diameter range between 2 nm and 10 nm). Stable functionalized gold nanoparticles were synthesized by using two different routes: a two-phase liquid-liquid method and a one-phase method. The size, strain, shape and crystalline structure of the nanocrystals were determined by a full-pattern X-ray powder diffraction analysis and high-resolution electron microscopy. The chemical environment of the Au nanocrystals and their interaction with the thiols was investigated by X-ray photoelectron spectroscopy. Photoluminescence spectroscopy measurements show a characteristic IR emission at λ=960 nm of small sized Au nanocrystals (∼3 nm). The origin of this IR emission line seems to be correlated to the Au-S bonding and the size of the nanoparticles.

Characterization of Palladium Nanoparticles by Using X-ray Reflectivity, EXAFS, and Electron Microscopy

We compared the characteristics of dodecanethiolate palladium nanoparticles synthesized by two different techniques, a one-phase method and a two-phase method. From transmission electron microscopy (TEM), we determined that the particle sizes were 46 +/- 10 angstroms and 20 +/- 5 angstroms for the one- and two-phase particles, respectively. Electron diffraction confirmed that their structure was face-centered cubic (fcc). The lattice constant a0 was 3.98 +/- 0.01 angstroms and 3.90 +/- 0.01 angstroms for the one- and two-phase particles, respectively. High-resolution TEM (HRTEM) showed that the one-phase particles had an ordered core surrounded by a disordered shell structure, while the two-phase particles appeared to be crystalline throughout. The particles were also analyzed with extended X-ray absorption fine structure (EXAFS). A cuboctahedral fcc model was used to fit the data, which implied particle sizes of less than 10 angstroms for both the one- and two-phase particles. The discrepancy between the two techniques was attributed to the presence of a disordered phase, which we presumed was composed of Pd-S compounds. Compared with the bulk palladium, lattice expansion was observed in both one- and two-phase particles by electron diffraction, HRTEM, and EXAFS. At the air/water interface, a uniform film that produced surface pressure/area isotherms could only be obtained from the two-phase particles. The one-phase particles did not wet the water surface. X-ray reflectivity data indicated that the Langmuir monolayer of the two-phase particles was only 13 angstroms thick. TEM revealed the diameter of the particles in this layer to be 23 angstroms; hence the particles assumed an oblate structure after spreading. EXAFS examination of a stack of 750 Langmuir monolayers indicated far fewer Pd-S compounds, which may have dissolved in the water. The data were consistent with a model of a monolayer of truncated cuboctahedron Pd particles that were 7 angstroms thick and 19 angstroms in diameter.

Synthesis of Thiolate-Stabilized Platinum Nanoparticles in Protolytic Solvents as Isolable Colloids

Water-dispersible, isolable thiolate-stabilized platinum nanoparticles are synthesized by two one-phase methods: one is conducted in water; another mainly in methanol, through the reduction of chloroplatinic acid with sodium borohydride, using mercaptosuccinic acid (MSA) as the stabilizer. The well-separated particles with mean diameter of 2.5 nm are obtained in water when the initial molar ratio of MSA to chloroplatinic acid (S/Pt) is 0.7. High-resolution transmission electron microscopy reveals that most particles are fcc single crystals of cuboctahedral or truncated octahedral morphology with cell parameter similar to that of bulk Pt. The average particle diameter increases from 2.5 nm to around 4.7 nm upon decreasing the S/Pt ratio from 0.7 to 0.1; at the same time, particle aggregation occurs due to the incomplete coverage of thiolate molecules on the particle surface. The particles with mean diameter of 2.3 nm are also obtained while using methanol as the solvent at an initial S/Pt ratio of 0.5. Ex...

One-phase reverse zymography after denaturing gel electrophoresis: High sensitivity detection of activity of plasminogen activator inhibitor 2 and other protease inhibitors

Summary A one-phase reverse zymography is described for the detection of activity of protease inhibitors after electrophoresis in denaturing conditions. The method is based on a previously described one-phase zymography designed to detect protease activity. 1 The reverse method contains the following steps: (1) electrophoretic separation of sample components in a sodium dodecyl sulphate (SDS)-polyacrylamide gel that also includes casein, and, if necessary, plasminogen as substrates for proteolytic enzymes. (2) Gel-wash in Triton X-100 to restore SDS-denatured biological activity of sample components. (3) Incubation of the gel with a desired proteolytic enzyme that can clear casein directly or indirectly. (4) Gel staining for casein left undegraded. Activity of protease inhibitors is visualized in the gel as dark bands against the background that was cleared from casein by the protease included in the incubation mixture. The major advantage of the method is the capability to also visualize activity of plasminogen activator inhibitors 2 (PAI-2) whose detection after denaturing conditions has been so far very limited. The one-phase method is convenient and highly sensitive, allowing the detection of plasminogen activator inhibitor 1 (PAI-1) and PAI-2 at the nanogram range. Other inhibitors visualized through this method included α 2 -antiplasmin, α 1 -antitrypsin, soybean trypsin inhibitor and trypsin inhibitory activity co-purified and co-migrating with chicken ovalbumin. Examination through the method of an array of cell lines revealed that most of them secreted inhibitors of urokinase-type plasminogen activator (u-PA) and trypsin, thus pointing to the necessity for cells to counteract proteolysis in their external environment.

Marking: the One-Phase and Two-Phase Methods

Journal Article Marking: the One-Phase and Two-Phase Methods Get access Michael Kitto Michael Kitto Search for other works by this author on: Oxford Academic Google Scholar ELT Journal, Volume 34, Issue 1, October 1979, Pages 64–67, https://doi.org/10.1093/elt/34.1.64 Published: 01 October 1979