A single multiplex PCR and SNaPshot minisequencing reaction of 42 SNPs to classify admixture populations into mitochondrial DNA haplogroups

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Investigation of the pore blockage of a Brazilian dolomite during the sulfation reaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoluminescence property of Ba(Zr0.25Ti0.75)O-3 powders prepared by solid state reaction and polymeric precursor method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Investigation of Ferroelectric Layered Perovskite Barium Bismuth Tantalate Prepared by Solid-State Reaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemiluminescence induced in the laser-promoted reaction of ethanol with oxygen

The vibrational multiphoton excitation of ethanol in the presence of oxygen results in chemiluminescent reactions yielding CH* and C*2. The rise times of the chemiluminescence become progressively slower and the intensity increases with ad-O2 pressure. At 15 Torr of O2 the emission duration is longer than 10 μs. © 1983.

Kinetics of the reaction of alkylamines with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in organic solvents

The following sequence of substitution reactions was studied spectrophotometrically in organic solvents: RNH2 + TCNQ →-HCN 7-substituted TCNQ →-HCN +RNH2 7.7-disubstituted TCNQ where R = butyl, octyl, dodecyl, and hexadecyl. The production of 7-(alkylamino)-7,7,8-tricyanoquinodimethanes proceeds via the formation of the anion radical of TCNQ (TCNQ-·) whose rate of appearance was found to be a function of the chain length of R, reaching a maximum for octylamine. The formation of TCNQ-· was sensitive to the solvent polarity and electron-donor power and was associated with a small enthalpy and a highly negative entropy of activation. Above a certain [C8H17NH2] the rate of disappearance of TCNQ-· was independent of the amine concentration, and the reaction had a much higher enthalpy and entropy of activation. The occurrence of tautomerism precluded an investigation of the conversion of 7-(octylamino)-7,8,8-tricyanoquinodimethane into 7,7-bis(octylamino)-8,8-dicyanoquinodimethane. A study of the reaction of octylamine with 7-morpholino-7,8,8-tricyanoquinodimethane (which does not exist in tautomeric forms) showed that the second substitution step proceeds with the same mechanism as the first one. The only difference between the two compounds (TCNQ and its monosubstituted morpholino derivative) is one of reactivity. © 1985 American Chemical Society.

Reaction of the human gingival tissue to different suture materials used in periodontal surgery.

The gingival reaction to 4 different suture materials used in periodontal surgery was studied in 36 patients. The gingiva was sutured prior to surgery and biopsies were taken at 3, 7 and 14 days to observe the tissue reaction. The histological examination showed that silk caused the most intense and longest inflammatory response. Polyester and perlon provoked shorter, less intense tissue reactions than silk, and nylon caused the least inflammatory response, with earlier tissue repair.

Contribution to the study of the reaction of mercury with platinum and a platinum-iridium alloy

Thermogravimetry (TG) and other analysis techniques have been used to study the reaction of mercury with Pt and a PtIr alloy. The results suggested that, when heated, the electrodeposited Hg film reacts with Pt or with PtIr to form products of different stabilities, indicated by at least three weight loss steps. In the first step, between room temperature and 170°C, only the bulk Hg is removed. From this temperature to about 280°C the mass loss can be attributed to the desorption of a monolayer of mecury. The last step, from 280 to ≈600°C, can be ascribed to the removal of Hg from a solid solution with Pt and PtIr alloy. © 1995.

Synthesis of lanthanide oxysulfides activated by Eu3+. A topochemical reaction

The oxysulfide compounds La2O2S:Eu and Y2O2S were obtained directly from thermodecomposition of the respective oxalate compounds under argon and sulfur vapor, the obtained compounds were analyzed by infrared spectroscopy, X ray diffraction and luminescence spectroscopy. The particle size distribution and crystalline habit of the compounds were observed by scanning electron microscopy. Although the particle size of the oxysulfide was found to be 30%-40% smaller than the precursor oxalates, the initial morphology was completely maintained, which indicates the occurrence of a topochemical reaction from oxalates to oxysulfides. © Gauthier-Villars.

Detection of leptospires in bovine semen by polymerase chain reaction

Objective: In view of the considerable importance of venereal transmission of bovine leptospirosis, the objective of the present study was to compare the polymerase chain reaction (PCR), culture/isolation and serology to detect leptospire infection in bovine semen. Design: Blood for serologic examination and semen for bacterial culture and PCR were collected from 20 bulls at artificial insemination centres in Brazil. Each animal was sampled twice for serology. Result: Forty-five percent (9/20) of the serum samples collected showed agglutinin titers to serovar hardjo in the first sample and 25% (5/20) had agglutinin titers to serovar hardjo in the second sample. Eighty percent (16/20) of semen samples were positive by PCR. Leptospires could not be isolated from any of the semen samples examined. Conclusion: Polymerase chain reaction can be a method of great potential for the detection of leptospires at artificial insemination centres.

Reaction of rat connective tissue to implanted dentin tubes filled with mineral trioxide aggregate or calcium hydroxide

This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted dentin tubes filled with calcium hydroxide or mineral trioxide aggregate. The animals were sacrificed after 7 and 30 days, and the specimens were prepared for morphological study. Some undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for calcium. The results were similar for both studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. It is possible that the mechanism of action of both materials has some similarity. Copyright © 1999 by The American Association of Endodontists.

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo. Copyright © 1999 by The American Association of Endodontists.

Contribution to the study of the solid-state reaction of mercury with pure rhodium

Thermogravimetry (TG) and other analysis techniques (EDX, SEM, Mapping surface, X-ray diffraction, inductively coupled argon plasma emission spectroscopy and atomic spectrometry with cold vapor generation) were used to study the reaction of Hg with Rh. The results permitted the suggestion that, when subjected to heat, an electrodeposited Hg film reacts with Rh to form intermetallic products with different stabilities, as indicated by at least three mass loss steps. In the first step, between room temperature and 160°C, only the bulk Hg is removed. From this temperature up to about 175°C, the mass loss can be attributed to the desorption of a film of metallic Hg. The last step, from 175 to 240°C, can be ascribed to the removal of Hg from a thin dark film of RhHg2.

Structure of thrombin complexed with selective non-electrophilic inhibitors having cyclohexyl moieties at P1

The crystal structures of five new non-electrophilic β-strand-templated thrombin active-site inhibitors have been determined bound to the enzyme. Four co-crystallize with hirugen and inhibitor isomorphously to produce thrombin-hirugen crystals (monoclinic, space group C2), while one co-crystallizes in the hexagonal system, space group P65. A 1,4-substituted cyclohexyl moiety is conserved at the P1 position of all the inhibitors, along with a fused hetero-bicyclic five- and six-membered ring that occupies the P2 site. Amino, amidino and aminoimidazole groups are attached to the cyclohexyl ring for recognition at the S1 specificity site, while benzylsulfonyl and diphenyl groups enhance the binding at the S3 subsite. The cyclohexyl groups at the P1 positions of three of the inhibitors appear to be in the energetically favored chair conformation, while the imidazole-substituted cyclohexyl rings are in a boat conformation. Somewhat unexpectedly, the two cyclohexyl-aminoimidazole groups bind differently in the specificity site; the unique binding of one is heretofore unreported. The other inhibitors generally mimic arginyl binding at S1. This group of inhibitors combines the nonelectrophilicity and selectivity of DAPA-like compounds and the more optimal binding features of the S1-S3 sites of thrombin for peptidic molecules, which results in highly potent (binding constants 12 nM-16 pM, one being 1.1 μM) and selective (ranging from 140 to 20 000 times more selective compared with trypsin) inhibitors of thrombin. The binding modes of these novel inhibitors are correlated with their binding constants, as is their selectivity, in order to provide further insight for the design of therapeutic antithrombotic agents that inhibit thrombin directly at the active site.