Guarini, Juvarra e Antonelli. Segni e simboli per Torino

Valentina Filemio reports on a 2008 exhibit in Turin, Italy, that focussed on architects Guarino Guarini, Filippo Juvarra and Alessandro Antonelli. Palazzo Bricherasio, Turin, Italy 28 June – 14 September 2008     

Optimization protocol for amyloid-β peptides detection in human cerebrospinal fluid using SELDI TOF MS

Purpose: The aim of the present work was to set up an optimized protocol for human cerebrospinal fluid amyloid‐β (Aβ) profiling. Experimental design : We devised an immunoproteomic assay that employs monoclonal antibodies (mAbs) on Preactivated Surface (PS20) chip array followed by SELDI TOF MS. A comparison of a number of factors was performed, and the impact of these differences was noted. Each variable was tested using in parallel two different mAbs, 6E10 and 4G8. In addition, we tested whether the combined use of these two mAbs could improve the capture of N and C‐terminally truncated Aβ peptides and then the quality of spectra. Results : The best results were obtained using a mixture of Aβ mAbs (0.125μg/μL 6E10+4G8): 15 Aβ peptides (including 3 N‐terminally truncated forms) were detected. Conclusions and clinical relevance : This approach has many potential advantages in speed, sensitivity and economy of reagents and could be helpful in order to define the role played by specific Aβ truncated forms in cognitive decline.     

Highly cited Soviet journals in the physical and life sciences: A study of the function of journals

The research developed from the identification of the most highly cited Soviet journals in the physical and life sciences. Several measures of growth and citedness were taken at the beginning and end of a recent five-year period, 1982–87, in order to generally assess the functions of these journals. The research involved making comparisons among these groupings of journals and control groupings of journals with similar content, but not published in the Soviet Union. Differences in citedness could be related, in the physical sciences, to the scale of Russophone science within world sciences, but not in the life sciences. In the physical sciences, there are increases in the citedness across Soviet and Western journals; but in the Soviet journals the increase is several times greater than in the control grouping. In sharp contrast, the largest, most cited, Western life sciences' journals have increased in citedness and other groupings, including Soviet journals, have declined. The measures on control groups show that the extreme levels of improvement in citedness on the part of Soviet physical sciences' journals reflect local, i.e. Soviet, developments. The decrease in citedness of Soviet life sciences' journals seems, instead, tied broadly to events in the world life sciences' literature. There has been, apparently a centralizing of attention within those discipline on those few journals publishing major findings while leaving the rest of the world literature behind. In addition, the research developed several findings on the formal properties of the measures used.     

Effect of Temperature on the Torrefaction of Peat

The effect of temperature on the torrefaction (mild pyrolysis) of peat was studied. The process was carried out under anaerobic conditions at atmospheric pressure and a temperature of 230–300°C. It was established that an increase in the temperature from 230 to 270°C leads to a certain decrease in the yield of biocoal and an increase in the gas formation. However, in this case, the fraction of carbon in the material increases by 10%. As a result, the calorific value of solid fuel increases to 25–26 MJ/kg. The process is characterized by a high carbon efficiency (about 90%)     

In situ TiC particle reinforced TiCuZrNi brazing alloy for joining C/C composites to Ti6Al4V

Chromium carbide modified C/C and Ti6Al4V were successfully joined using a TiCuZrNi brazing alloy in powder form. The braze/composite interface and the mechanical strength of C/C‐Ti6Al4V joints were evaluated. The apparent shear strength of chromium carbide modified C/C joined to Ti6Al4V, measured by single lap test in compression, was 52 ± 6 MPa, which was highest among that without chromium carbide modification (15 ± 2 MPa) and the intrinsic C/C shear strength. The fractography of joints without chromium carbide modification indicated that failure mainly occurred at the TiC layer formed at the composite/braze interface while the joints with chromium carbide modification failed within the C/C.     

Mixing Under Vibrations in Reduced Gravity

The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two initially stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures (Sc?=?7125) are considered. The vibrations with a constant frequency are imposed parallel to the initially planar interface. The ability of the applied vibrations to enhance the flow is examined. At the early stage after imposing the vibrations the Kelvin-Helmholtz instability is observed in absence and at low level of gravity. Later in time the system undergoes a transition to Rayleigh-Taylor instability. With increasing of gravity level the life-time of Kelvin-Helmholtz instability is decreased. We found the critical value of Gr above which this instability do not developed.     

Protein and electrode engineering for the covalent immobilization of P450 BMP on gold

Site-directed mutagenesis and functionalization of gold surfaces have been combined to obtain a stable immobilization of the heme domain of cytochrome P450 BM3 from Bacillus megaterium. Immobilization experiments were carried out using the wild type protein bearing the surface C62 and C156 and the site-directed mutants C62S, the C156S, and the double mutant C62S/C156S (no exposed cysteines). The gold surface was functionalized using two different spacers: cystamine- N-succinimidyl 3-maleimidopropionate and dithio-bismaleimidoethane, both leading to the formation of maleimide-terminated monolayers capable of covalent linkage to cysteine. Tapping mode atomic force microscopy experiments carried out on cystamine- N-succinimidyl 3-maleimidopropionate derivatized gold led to good images with expected molecular heights (5.5-6.0 nm) for the wild type and the C156S mutant. These samples also gave measurable electrochemical signals with midpoint potentials of -48 and -58 mV for the wild type and C156S, respectively. On the other hand, the dithio-bismaleimidoethane spacer led to variability on the molecular heights measured by tapping mode atomic force microscopy and the electrochemical response. This is interpreted in terms of lack of homogeneous dithio-bismaleimidoethane monolayer on gold. Furthermore, results from tapping mode atomic force microscopy show that the double mutant and the C62S did not lead to stably immobilized P450 protein, confirming the necessity of the solvent exposed C62.     

Apatite formation and cellular response of a novel bioactive titanium

The modification of titanium and titanium alloy surface properties by chemical and electrochemical techniques has opened new possibilities to improve the bioactivity and, in general, the biological performance of the implants once in vivo. One of the main aims is the achievement of a surface oxide layer that stimulates hydroxylapatite mineralization and, also, shows osteoconductive properties once in the host. In the present study, two different bioactive surfaces have been prepared following the method purposed by the group of Kokubo and a new method, BioSpark™, involving high voltage anodic polarisation and alkali etching both on surface mineralization potential. The aim of the present work was to evaluate and compare the mineralization capability and the early cell response of titanium modified with a new bioactive method and with a well-known and widely tested biomimetic treatment, both compared to non treated titanium. Physical and chemical (energy dispersion spectroscopy, thin film X-ray diffractometry) and morphological (scanning electron microscopy) characterisation of the novel surface features has been performed. Also the effect of the novel surface properties on both hydroxyapatite precipitation and early cellular response has been investigated using in vitro models. The results have shown that both treatments produce an active outer layer on titanium but do not impair cells activity and support osteoblasts processes. BioSpark™ showed high bioactivity and good mineral phase deposition even after early incubation time, these properties were found in Kokubo’s surface as previously published. Mineralisation mechanisms of the two materials were different, and while this mechanisms was well characterised and reported for Kokubo’s surface, it was still unclear for BioSpark™. In this paper an explanation was given and catalytic properties of the latter surface was bound to both well known crystal titanium oxide exhibiting anatase lattice and a certain level of calcium and phosphorus doping, which promoted chemical and physical variation in anatase properties. At the same time early osteoblasts response to Kokubo’s and BioSpark™’s surface was characterised and, no significant differences was found.     

Directed three-dimensional patterning of self-assembled peptide fibrils

Molecular self-assembly is emerging as a viable "bottom-up" approach for fabricating nanostructures. Self-assembled biomolecular structures are particularly attractive, due to their versatile chemistry, molecular recognition properties, and biocompatibility. Among them, amyloid protein and peptide fibrils are self-assembled nanostructures with unique physical and chemical stability, formed from quite simple building blocks; their ability to work as a template for the fabrication of low resistance, conducting nanowires has already been demonstrated. The precise positioning of peptide-based nanostructures is an essential part of their use in technological applications, and their controlled assembly, positioning, and integration into microsystems is a problem of considerable current interest. To date, their positioning has been limited to their placement on flat surfaces or to the fabrication of peptide arrays. Here, we propose a new method for the precise, three-dimensional patterning of amyloid fibrils. The technique, which combines femtosecond laser technology and biotin-avidin mediated assembly on a polymeric matrix, can be applied in a wide variety of fields, from molecular electronics to tissue engineering.     

Adsorption of Dinitrogen Tetroxide (N2O4) on Multi-walled Carbon Nanotubes (MWCNTs)

The adsorption of dinitrogen tetroxide (N₂O₄) on multi-walled carbon nanotubes (MWCNTs) has been studied by FT-IR, Raman and X-ray photoelectron spectroscopy (XPS). The N₂O₄ adsorption is fully reversible, and after the desorption there is no evidences of MWCNTs nitration. Instead, the MWCNTs have been found oxidized by the action of N₂O₄. By thermogravimetric analysis (TGA) about 5% by weight of oxygenated groups have been found. Thermal analysis has revealed that MWCNTs having a surface area of 275 m²/g are able to reversibly adsorb about 25% by weight of N₂O₄, a value comparable to that observed for certain active carbons.