Evolution of Cavitation Activity During Ultrasonic Nanostructuring of Magnesium

In this paper we focus on the investigation of the transient cavitation activity evolution during the sonochemical treatment of magnesium aqueous suspensions. We investigated the nonlinear behavior of cavitation activity that can be related with the influence of hydrogen gas released in the reaction of magnesium with water. Ultrasound causes the modification of the magnesium particles leading to the formation of the nanostructured Mg(OH)2 phase (brucite) resulting from both chemical and sonochemical impacts on the magnesium

Association of antibodies to benzo[a]pyrene, estradiol and progesterone with gene polymorphisms of cytokines in postmenopausal women

Previous studies reported some associations between IgA and IgG antibodies specific to benzo[a] pyrene (Bp), estradiol (Es) and progesterone (Pg), and breast cancer (BC) in postmenopausal women. Likewise, the individual ratios of these antibodies (IgA-Bp/IgA-Pg, IgG-Bp/IgG-Pg, IgG-Es/IgG-Pg, IgG-Es/IgG-Pg) were associated with BC. It was suggested that development of antibodies to chemical carcinogens and steroid hormones was determined by functional polymorphisms of cytokine genes. The purpose of this study was to identify the suggested associations of antibodies to Bp, Es, Pg, and their individual ratios to the following gene polymorphisms: IL1RN (rs4251961), IL1B (rs16944), IL6 (rs1800795, rs1800796, rs1554606), IL8 (rs4073), TNFA (rs1800629) and CD40 (rs6074022) detected in postmenopausal healthy women and BC patients.The serum IgA and IgG antibodies specific to Bp, Es and Pg were studied in 470 healthy women and 995 BC patients by non-competitive solid phase immunoassay. The conjugates of Bp, Es, Pg with bovine serum albumin were used as adsorbed antigen. The goat antibodies against human IgA or IgG conjugated with horseradish peroxidase were used for the detection of bound hapten-specific antibodies. Cytokine gene polymorphisms were analyzed by the real-time PCR.Associations between the studied antibodies and their ratios with the gene polymorphisms in IL1RN (rs4251961), IL6 (rs1800795), TNFA (rs1800629) and CD40 (rs6074022) were found in healthy women. Higher individual ratios of IgA-Bp/IgA-Pg (p = 0.0001), IgG-Bp/IgG-Pg (p < 0.0001), IgG-Es/IgG-Pg (p = 0.0003) were associated with the allele C gene IL1RN. The higher IgG-Es levels were more common in the persons with allele G gene IL6 (p = 0.007), and with C allele of CD40 gene (p = 0.005). The high IgA-Pg levels were associated with A allele gene of TNFA (p = 0.008). Associations of antibodies were found only with genes polymorphisms in CD40 (rs6074022) in BC patients. Higher IgG-Es levels were more common in persons with allele T gene CD40 (p = 0.007).In conclusion, we revealed the participation of cytokines in immune regulation of antibody genesis for environmental chemical carcinogens and endogenous steroid hormones in healthy women and BC patients. The future investigations of antibodies specific to Bp, Es and Pg combined with the analysis genes polymorphisms in cytokines will be useful for detection of the individual hormone-dependent cancer risks in humans

Characterization of transient cavitation activity during sonochemical modification of magnesium particles

Investigation of the cavitation activity during ultrasonic treatment of magnesium particles during nanostructuring has been performed. Cavitation activity is recorded in the continuous mode after switching the ultrasound on with the use of ICA-5DM cavitometer. It has been demonstrated that this characteristic of the cavitationzonemaybevariedinawiderangeofconstantoutputparametersofthegenerator.Thespeedand natureofthecavitationactivityalterationdependedontheconcentrationofMgparticlesinthesuspensionand the properties of the medium in which the sonochemical treatment has been performed. Three stages of the cavitation area evolution can be distinguished: 1 – the initial increase in cavitation activity, 2 – reaching a maximumwithasubsequentdecrease,and3–reachingtheplateau(ortherepeatedcycleswithfeedbackloops ofenlargement/reductionofthecavitationactivity). Theultrasonicallytreatedmagnesiumparticleshavebeencharacterizedbyscanningelectronmicroscopy,Xraydiffractionanalysisandthermalanalysis.Dependingonthenatureofthedispersedmediumtheparticlescan be characterized by the presence of magnesium hydroxide (brucite) and magnesium hydride. It is possible to reachtheincorporationofmagnesiumhydrideinthemagnesiumhydroxide/magnesiummatrixbyvaryingthe conditionsofultrasonictreatment(durationoftreatment,amplitude,dispersedmediumetc.).Theinfluenceof the magnesium reactivity is also confirmed by the measurements of cavitation activity in organic dispersed media(ethanol,ethyleneglycol)andtheiraqueousmixtures

Switching the stiffness of polyelectrolyte assembly by light to control behavior of supported cells

Polyelectrolyte block copolymer micelles assembled thin film is switched in response to local photocatalytic reactions on titanium dioxide, resulting in a layer of variable height, stiffness in response to visible light irradiation. Preosteoblasts migrate toward stiffer side of the substrates.Front Cover: There are great prospects of conversion of energy of electromagnetic irradiation into pH gradients enabling also spatial regulation by localization of the irradiation spot onto a semiconductor titania surface to guide cells on a surface that promises many applications in biosciences, fundamental cell biology and microfluidics. Further details can be found in the article by Sviatlana A. Ulasevich, Nadzeya Brezhneva, Yulia Zhukova, Helmuth Möhwald, Peter Fratzl, Felix H. Schacher, Dmitry V. Sviridov, Daria V. Andreeva, Ekaterina V. Skorb on page 1422

Using a chitosan nanolayer as an efficient pH buffer to protect pH-sensitive supramolecular assemblies

It is attractive to control the properties of macro objects and films by employing simple nanolayer composites, as in the case of nanoarchitectured Layer-by-Layer (LbL) coating. In this paper, we use chitosan as a surface-based pH buffer to protect adsorbed supramolecular fibres from pH-mediated disassembly. Protons are generated on a titania surface under illumination at 405 nm leading to an appreciable pH change on the surface. We find that supramolecular polymers that are highly sensitive to pH change will not disassemble after irradiation if a nanolayer of chitosan is present. We propose that chitosan can be used as an efficient pH-responsive protective layer for pH sensitive soft materials