Incubation-based hydroxyapatite synthesis method using shells as Ca2+ source

Hydroxyapatite, the well-known calcium phosphate, was obtained on the surface of shells fragments by partial conversion of the latter, which served both as template and also provided the calcium ions required for synthesis. Confirmation of hydroxyapatite formation was acquired by recording and analyzing X-ray diffraction patterns. The degree to which the phosphate ions were consumed during the incubation-based synthesis was determined using a phosphate minicolorimeter, and the results indicate that a nucleation process takes place in the first 4 hours

Influence of nucleation centers upon solvothermal growth of silver nano/microcrystals

Silver nano/microcrystals were obtained at medium pressure in a microwave field by using the solvothermal synthesis. In order to evaluate the nucleation centers’ influence upon the formed crystals’ morphology, investigations were conducted using scaffolds to stimulate their heterogeneous nucleation. Therefore, besides the silver and chloride nanocrystals used as nucleation centers, SiOx type spheres were used. The results indicate that the presence of the heterogeneous nucleation centers on the SiOx scaffolds plays a crucial role in the silver nano/microcrystals morphology

Dimensional distribution of PM2.5 and PM10 in the road proximity

The particulate matter (PM) is comprised of two kinds of particles, classified after their dimensions, the PM2.5 which encompasses particles with sizes smaller than 2.5 µm and the PM10 with particles ranging in size from 2.5 µm to 10 µm. As previous studies have shown, PMs have an undeniable influence, dependent on the exposure time, upon the health of the human cardiopulmonary system. In this study we focused on the dimensional distribution of PMs and the influence of altitude on their numbers. Our detailed investigation lead us to the conclusion that the particle number is increasing at higher altitudes and also that PM2.5, which represents a greater health risk factor, is much more abundant than PM10

Hydrothermal synthesis of hydroxyapatite with tartaric acid

The hydrothermal synthesis of hydroxyapatite (HA) with addition of tartaric acid (TA) is presented in the paper. The role of tartaric acid is to form a complex with the Ca ions and to help in tailoring the crystallization behavior of hydroxyapatite. A comparison is made between two situations: one is characterized by the addition of tartaric acid after the precipitation of hydroxyapatite, and the other is defined by tartaric acid being added to the Ca precursor, followed by the addition of the P precursor. The crystalline particles resulted were studied by means of XRD, FTIR, SEM and TEM, and it was concluded that they consist in hexagonal lamellar crystals with lengths < 200 nm and widths < 50 nm. The difference between the two cases is that the crystallinity degree, the uniformity in crystal dimensions and the aspect ratio are higher when TA was added before the precipitation rather than to the precipitated HA. The dimensions of the achieved crystals are similar to the mineral grains found in the hard tissues of the human body

Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections

Dentists, members of the French Resistance movement during the World War II

The Resistance was a reaffirmation of France's independence and individuality, as well as a struggle to regain freedom and, above all, national integrity. In fact, many historians appreciate that the French Resistance could have achieved more if it had been more effectively integrated into Allied plans and strategies. Thus, in this material we tried to present some short biographies of dentists who worked in the French Resistance against the German occupation troops, some of them even paying with their lives for the courage they showed