Analysis of Damage on the Streptococcus mutans Immersed in Ozonated Water: Preliminary Study for Application as Mouth Rinse

Ozonated water has been demonstrated to induce significant results in terms of the elimination of microorganisms. The present study assessed the damage to Streptococcus mutans after exposure to ozonated water; the ozone generator was adjusted to provide an outlet concentration of 60 mg/L, the samples were submitted to different ozonation times 1, 2, 4, 6, and 10 mi. Scanning electron microscopy and atomic force images were obtained to identify damage to the bacteria, followed by reactive oxygen species (ROS) evaluation and microbial viability. The results showed a significant reduction in viability and the images evidenced the generation of gaps on the microbial wall and surface layer alterations. Ozone can induce significant damage to S. mutans, thus suggesting that the use of ozonated water to prevent carious lesion formation is extremely promising.     

Characterization of Crude Watermelon Seed Oil by Two Different Extractions Methods

The aim of this paper was to study the physical–chemical composition of the watermelon seed oil extracted by a mechanical process using an expeller and by a chemical process using hexane as the solvent. The watermelon seed oil had a high concentration of unsaturated fatty acids. The two primary sterols were stigmasterol and β-sitosterol, which corresponded to approximately 47 and 30% of the total phytosterols. The oil had a low tocopherol content (65.19 mg/kg for S and 73.19 mg/kg for E). Comparing the two extraction methods, extraction by expeller produced an oil of superior quality with respect to oxidative stability, carotenoids and Lovibond color. No significant differences were found between the two extraction methods with respect to the minor components of the oil considered as functional, such as phytosterols.     

Peptide‐Based Fluorescent Probes for Deacetylase and Decrotonylase Activity: Toward a General Platform for Real‐Time Detection of Lysine Deacylation

Histone deacetylases regulate the acetylation levels of numerous proteins and play key roles in physiological processes and disease states. In addition to acetyl groups, deacetylases can remove other acyl modifications on lysines, the roles and regulation of which are far less understood. A peptide‐based fluorescent probe for single‐reagent, real‐time detection of deacetylase activity that can be readily adapted for probing broader lysine deacylation, including decrotonylation, is reported. Following cleavage of the lysine modification, the probe undergoes rapid intramolecular imine formation that results in marked optical changes, thus enabling convenient detection of deacylase activity with good statistical Z′ factors for both absorption and fluorescence modalities. The peptide‐based design offers broader isozyme scope than that of small‐molecule analogues, and is suitable for probing both metal‐ and nicotinamide adenine dinucleotide (NAD⁺)‐dependent deacetylases. With an effective sirtuin activity assay in hand, it is demonstrated that iron chelation by Sirtinol, a commonly employed sirtuin inhibitor, results in an enhancement in the inhibitory activity of the compound that may affect its performance in vivo.     

A note on high-Q active networks

Levi's and Zeheb's approach for approximating a high-Q second-order section by n sections with lower Q's is compared with the optimal solution of this problem proposed by Khazanov. Tables relating the maximum error in the approximation to the values of n and the achievable Q-reduction (QR) are also given. They should prove useful to the designer. Finally, some comments on sensitivities are added.     

Effect ofSolanum Glycoalkaloids on Potato Aphid,Macrosiphum euphorbiae

Macrosiphum euphorbiae, also known as the potato aphid, is a potato virus vector, associated with decreased tuber production. Feeding, toxicity, and reproductive effects of the major potato glycoalkaloids (α-chaconine and α-solanine), their common aglycone (solanidine), and a nonpotato glycoalkaloid (α-tomatine) and its aglycone (tomatidine) onM. euphorbiae were studied. As expected, neither α-chaconine nor α-solanine had a strong lethal effect on the aphid, but α-chaconine stimulated feeding at low concentrations. Both aglycones were deterrent and lethal at high concentrations and, like α-chaconine and α-tomatine, they delayed the appearance and decreased the number of nymphs.     

Comparative Analysis of Ozone and Ultrasound Effect on the Elimination of Giardia spp. Cysts from Wastewater

Giardia spp. is a flagellate protozoan that presents two evolution forms, cysts and trophozoites. Cysts are resistant to chlorine, the most employed disinfectant agent in the treatment of water. For this reason, new techniques for the disinfection of waters that contain this parasite are necessary. This work evaluated the efficiency of the disinfection by ozone and ultrasound individually and simultaneously upon wastewater. The data obtained showed that after application, ozone, ultrasound, and combined techniques induced a significant elimination of Giardia spp. cysts. Furthermore, this effect was more accentuated when the two techniques were applied simultaneously.     

Anisotropic molecular packing of soluble C60 fullerenes in hexagonal nanocrystals obtained by solvent vapor annealing

We describe the self-assembly of soluble, chemically modified fullerene [6,6]-phenyl C₆₁ butyric acid methyl ester (PCBM) into a new crystalline phase where the C₆₀ moieties are arranged in parallel layers. Minimum C₆₀ center-to-center distance is 10 Å within the layers, and up to 15 Å perpendicular to the layers. Highly anisotropic, mesoscopic hexagonal crystals of this material, with a lateral size of many microns and a thickness below 1 μm, are obtained from chloroform solution by solvent vapor annealing, and characterized by optical microscopy and X-ray diffraction. The crystalline structure is deduced combining experimental data with molecular modeling and ab initio calculations. The large difference in C₆₀–C₆₀ spacing indicates a high anisotropy in electrical and charge transport properties of this new phase.     

A theoretical evaluation of the effect of water on the electronic properties of low density amorphous carbon nanoparticles

Monte Carlo simulations combined with first-principles calculations were carried out to investigate the structure and electronic properties of amorphous carbon nanoparticles containing between 287 and 467 atoms, isolated and in an aqueous environment. Carbon interactions were described in terms of the semiemperical Tersoff potential and the interactions of the nanoparticles with water were described by an all-atom Lennard–Jones potential. The nanostructures were generated from low mass density amorphous carbon phases simulated under ambient conditions. Our study has indicated that the formation energy of these nanomaterials is slightly affected by the initial configuration of the amorphous phase. The large number of dangling bonds present in the nanostructures leads to huge magnetic moments, in a 31–42 μ_B range, calculated for the amorphous nanostructures containing distinct sp²/sp³ ratios. Also, these nanoparticles exhibit strong interaction energies with the aqueous environment, which are in agreement with the high reactivity expected for these amorphous systems. Most importantly, the calculated magnetism appears to be reduced between 1% and 14% in the presence of water, depending on both the nanoparticle density and surface.