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The wetting behavior of Cu-Ti powder compacts with 22 wt % Ti and 50 wt % Ti on carbon materials, including graphite and carbon fiber reinforced carbon composites (CFC), has been investigated in a vacuum using the sessile drop method. The equilibrium contact angles of Cu-22Ti (containing 22 wt% Ti) on the graphite and the CFC substrates at 1 253 K are 32° and 26°, respectively, whereas the equilibrium contact angle of 9° is obtained for Cu-50Ti (containing 50 wt% Ti) on both the graphite and the CFC substrates at 1 303 K. Microstructural analysis of the wetting samples shows that a thin TiC reaction layer is developed at the interfacial area and Ti-Cu intermetallic compounds are formed over the reaction layer. The investigation on the spreading kinetics of Cu-Ti compacts on carbon materials substrates at fixed temperatures reveals that the spreading is controlled by the interfacial reactions in the first stage and then by the diffusion of the active Ti from the drop bulk to the triple line in the later stage. The spreading is promoted by the intense reaction at higher Ti concentrations.

Purpose In this process the electrical contact is brought to the backside of a standard silicon wafer. The details of the entire process are disclosed, from the photolithography processes to the electrodepositing step, and a model for electrical contact was designed. Design/methodology/approach The localized Cu growth of high aspect ratio (AR) microstructures was obtained through an SU-8 photolithography by exploiting the optimal adhesion on the silicon surface and the possibility of generating thick layers with a single spun process Findings The experimental results showed an unexpected behaviour that is theoretically explained in detail considering the energy band theory. The obtained geometries showed a remarkable 6:1 AR without any adhesion problem. The non-invasive front-side manipulation represents a noteworthy improvement and simplification for the design of a multi-step production process. Originality/value An alternative technological approach, called back plate electroplating, has been carried out to obtain Cu growth on the front side of a standard n-type Si wafer through a back side electrical contact. This technique was then applied to fabricate a master for hot-embossing in a LIGA (Lithographie, Galvanoformung, Abformung)-like process flow. For this purpose, an SU-8 thick mask on a standard n-doped wafer was used. Finally, by using this process, it was possible to obtain high AR Cu geometries, avoiding any complex designing and patterning of the contacts on the front side and thus ensuring good adhesion of the SU-8.

A microfluidic platform for cell motility analysis in a three-dimensional environment is presented. The microfluidic device is designed to study migration of both single cells and cell spheroids, in particular under spatially and temporally controlled chemical stimuli. A layout based on a central microchannel confined by micropillars and two lateral reservoirs was selected as the most effective. The microfluidics have an internal height of 350 mu m to accommodate cell spheroids of a considerable size. The chip is fabricated using well-established micromachining techniques, by obtaining the polydimethylsiloxane replica from a Si/SU-8 master. The chip is then bonded on a 170-mu m-thick microscope glass slide to allow high spatial resolution live microscopy. In order to allow the cost-effective and highly repeatable production of chips with high aspect ratio (5:1) micropillars, specific design and fabrication processes were optimized. This design permits spatial confinement of the gel where cells are grown, the creation of a stable gel-liquid interface and the formation of a diffusive gradient of a chemoattractant (>48 h). The chip accomplishes both the tasks of a microfluidic bioreactor system and a cell analysis platform avoiding critical handling of the sample. The experimental fluidic tests confirm the easy handling of the chip and in particular the effectiveness of the micropillars to separate the Matrigel T from the culture media. Experimental tests of (i) the stability of the gradient, (ii) the biocompatibility and (iii) the suitability for microscopy are presented.

Copper patinas are generally regarded as aesthetically pleasing and are supposed to protect copper against further corrosion. The preparation of artificial sulphate patina on bronzes has been realized by immersing the bronze into CuSO4 solution. The effect of immersion time on the formation of the patina has been investigated. The sulphate patina obtained with immersion time of 500 h in CuSO4 solution consists of flat area and crystals. The flat area in the patina is mainly made of cuprite, whereas the crystals are mainly composed of brochantite. The electrochemical measurement of sulphate patina in simulated acid rain with pH 3.1 shows that the protective effectiveness of patina decreases with time and the dissolution of patina is the key factor leading to the degradation of patina. The investigation of the formation mechanism of sulphate patina shows that the cuprite layer forms on the surface of bronze in the initial patination. Then, crystal brochantite grows on the surface of cuprite by the oxidation of cuprite and the incorporation of CuSO4 solution.

In this work a polymer lab-on-a-chip (LOC), fabricated through MEMS technology, was employed to execute a genetic protocol for the Single Nucleotide Polymorphisms (SNPs) detection. The LOC was made in Poly (methyl methacrylate) (PMMA) and has two levels: the lower one for the insertion and mixing of the reagents, the upper one for the interfacing with the DNA microarray chip. The hereditary hearing loss was chosen as case of study, since the demand for testing such a particular disorder is high and genetics behind the condition is quite clear. The Arrayed Primer EXtension (APEX) genetic protocol was implemented on the LOC to analyze the SNPs. A low density (for detection of up to 10 mutations) and a high density microarray chips (for detection of 245 mutations in 12 genes), containing the primers for the extension, were employed to carry out the APEX reaction on the LOC. Both the microarray chips provide a signal to noise ratio and efficiency comparable with a detection obtained in a conventional protocol in standard conditions. Moreover, significant reduction of the employed PCR volume (from 30 mu L to 10 mu L) was obtained using the low density chip.

The tarnishing test in the presence of hydrogen sulfide (H2S) vapors has been used to investigate the tarnish resistance capability of copper-based alloys coated with SiO2-like films by means of plasma-enhanced chemical vapor deposition (PECVD) fed with a tetraethoxysilane/oxygen mixture. The chemical and morphological properties of the films have been characterized by using infrared absorption spectroscopy (IR) and scanning electron microscopy (SEM) with energy disperse spectroscopy (EDS). The corrosion products of the samples after the tarnishing test have been identified by X-ray diffraction analysis (XRD). It has been found that SiO2-like films formed via PECVD with a high O2 flow rate could protect copper-based alloys from H2S vapor tarnishing. The alloys coated at the O2 flow rate of 20 sccm remain uncorroded after 54 days of H2S vapor tarnish testing. The corrosion products for the alloys deposited at a low O2 flow rate after 54 days of tarnish testing are mainly composed of brochantite.

Hepatitis C virus (HCV) is one of the main causes of chronic liver disease worldwide. The diagnosis and monitoring of HCV infection is a crucial need in the clinical management. The conventional diagnostic technologies are challenged when trying to address molecular diagnostics, especially because they require a complex and time-consuming sample preparation phase. Here, a new concept based on surface functionalization was applied to viral RNA purification: first of all polydimethylsiloxane (PDMS) flat surfaces were modified to hold RNA adsorption. After a careful chemical and morphological analysis of the modified surfaces, the functionalization protocols giving the best RNA adsorbing surfaces were applied to PDMS microdevices. The functionalized microdevices were then used for RNA purification from HCV infected human plasma samples. RNA purification and RT were successfully performed in the same microdevice chamber, saving time of analysis, reagents, and labor. The PCR protocol for HCV cDNA amplification was also implemented in the microdevice, demonstrating that the entire process of HCV analysis, from plasma to molecular readout, could be performed on-chip. Not only HCV but also other microdevice-based viral RNA detection could therefore result in a successful Point-of-Care (POC) diagnostics for resource-limited settings.

The chromium addition remarkably improves the wettability of SiC/Ni–Cr systems within the Cr content range of 10–60 wt.%. For the SiC/Ni–51Cr system, a reaction layer about 100 μm thick exists between the SiC ceramic and the filler layer and is composed mainly of Ni 2 Si and graphite with a little Cr 23 C 6 , whereas the filler layer consists mainly of Cr 23 C 6 and Ni 2 Si. Both the interfacial reactions and the formation of reaction products contribute to the improvement of the wetting of SiC/Ni–Cr systems.

A cumulative sensor for in situ monitoring of H2S vapors in museum showcases based on plastic optical fiber (POF) has been developed. H2S is responsible for the tarnishing of silver artifacts, so monitoring their total exposure over time to sulfide rich atmospheres can help in choosing the correct display procedure and, consequently, lead to improvements in their conservation.

Surface engineering has been explored using plasma enhanced chemical vapur deposition (PECVD) of SiO2-like coatings on different metallic substrates in order to improve their resistance to corrosion. Specifically, the coatings have been deposited onto silver-based alloys which are prone to unaesthetic tarnishing, by means of PECVD in radio frequency (RF) plasma fed with tetraetoxysilane/oxygen/argon mixture. Microchemical and microstructural characterization of the coatings has been carried out by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The protective effectiveness against tarnishing of SiO2-like layers has been evaluated by immersion tests in 0.1M Na2S aerated solution at room temperature. It has been found that SiO2-like coatings deposited by increasing the oxygen-to-monomer ratio in the feeding-gas mixture and the input power density possess excellent barrier effects, and the coating adhesion increases if the deposition process is performed after a hydrogen plasma treatment. The protective effectiveness of PECVD coatings may be related to their barrier effect against the diffusion of water and other gaseous aggressive agents present in the environment and coming into contact with the metal surface. Copyright (C) 2010 John Wiley & Sons, Ltd.

Vetiver is the only grass cultivated worldwide for the root essential oil, which is a mixture of sesquiterpene alcohols and hydrocarbons, used extensively in perfumery and cosmetics. Light and transmission electron microscopy demonstrated the presence of bacteria in the cortical parenchymatous essential oil-producing cells and in the lysigen lacunae in close association with the essential oil. This finding and the evidence that axenic Vetiver produces in vitro only trace amounts of oil with a strikingly different composition compared with the oils from in vivo Vetiver plants stimulated the hypothesis of an involvement of these bacteria in the oil metabolism. We used culture-based and culture-independent approaches to analyse the microbial community of the Vetiver root. Results demonstrate a broad phylogenetic spectrum of bacteria, including alpha-, beta- and gamma-Proteobacteria, high-G+C-content Gram-positive bacteria, and microbes belonging to the Fibrobacteres/Acidobacteria group. We isolated root-associated bacteria and showed that most of them are able to grow by using oil sesquiterpenes as a carbon source and to metabolize them releasing into the medium a large number of compounds typically found in commercial Vetiver oils. Several bacteria were also able to induce gene expression of a Vetiver sesquiterpene synthase. These results support the intriguing hypothesis that bacteria may have a role in essential oil biosynthesis opening the possibility to use them to manoeuvre the Vetiver oil molecular structure.

Frequently, identification of individuals is problematical due to the level of associated decomposition and even more when the skeletal remains are incomplete or fragmented. The identikit, which includes a sketch or a facial reconstruction, could assist investigators with determining the identity of the decedent. Similarly, in archeology and physical anthropology it gives a realistic appearance to a historical character known only through iconography. We examined the skull of Angelo Poliziano, an Italian humanist of the 15(th) century. Previously, his facial approximation was completed in clay according to the Manchester protocol and then a duplication was prepared in ultra-realistic materials. This technique returns a long lasting 3D model of the individual and provides the perception to be in front of a real person and, although expensive, applied in forensic context could it improve the recognition of the individual.

Thin films are increasingly used both for the development of innovative gas sensors and for surface protection purposes due to availability of new surface treatments, such as those based on low pressure and atmospheric plasma processes. In many cases sequential treatments are required, where, after the initial deposition, the film is exposed to different chemical compounds that both react and diffuse inside the film, usually to enhance its properties. These reaction/diffusion processes depend on many parameters connected to the layer morphology and are, therefore, complex and difficult to preview. Several authors have studied the problem and have developed powerful mathematical models, whose validation, however, is difficult since making measurements during the transient process, especially for films with nanometric thickness, is not easy. In this paper, the authors investigate two optical solutions that can be applied to many practical cases to follow the diffusion process of gases in real time and thus tune and validate the models. The first solution is based on the well-known Surface Plasmon Resonance (SPR) phenomenon and allows precise evaluations to be obtained, but requires a lab-type setup. The other solution employs a Plastic Optical Fiber (POF) and exploits the evanescent field interaction to arrange a simple and cheap setup, that can be used also for in situ tests. Both approaches are applied to the study of the diffusion of sulfide vapors in silver with subsequent surface tarnishing, a topic that represents a practical case of relevant importance in the field of cultural heritage preservation.

An easy-to-use and cheap diagnostic tool based on digital photography and 2D-FFT imaging processing is described that can be used to monitor the corrosion process occurring over time on the surface of metallic works of art in indoor and outdoor environments and to assess the stability of the materials employed for restoration. The proposed solution has the advantage of not requiring standard lighting and artifacts manipulation, that are not easily achievable in real applications. The imaging algorithm is capable of highlighting the changes in the surface uniformity due to the corrosion process and can be used to put in evidence the beginning of dangerous localized corrosion phenomena onto the metallic surface. Although this technique does not allow a quantitative measurement of the corrosion rate, it has proved to be an effective approach to assess the stability of protective coatings. The proposed processing has been tested in laboratory to asses the stability of SiO2—like protective coatings deposited by PECVD on a set of silver reference alloys submitted to a tarnishing test in the presence of H2S vapors.

This paper describes the realization of a temperature sensor based on plasma sputtered thermocouples. The thermocouples are realized in the vacuum with quite pure materials, negligible oxydation and with low contamination thus enabling accurate measurements and are made inert by means of a thin coating of tetraethoxysilane (TEOS) that seals them. The thermocouples have an overall thickness of few hundreds of nanometers and are designed to allow non invasive, though accurate temperature measurement to be obtained in adverse conditions, such as the ones found during lyophilization processes. Lyophilization is widely employed to obtain pharmacological active powders in an economical and massive way. The lyophilization process effectiveness depends on the thermal distribution inside the lyophilizing vials: if the temperature is too low the process become extremely slow thus greatly increasing the powder cost, but if the temperature is too high a melting of the frozen substance can occur that can make the powder useless. Tuning the drying process is therefore extremely important, but such an operation is quite difficult since the temperature greatly changes inside each lyophilizing vial due to the process itself and among vials due to their position within the apparatus. A local temperature measurement would therefore be necessary, but normal temperature sensors would alter the drying local condition making the measurement incorrect and indirect measurements proved to be not reliable. The proposed solution instead is almost inert, capable of performing accurate local measurements and can be used in a variety of conditions where size and possible contamination are of importance. A sensor prototype is described and its performance compared with conventional sensors highlighting the advantages of the proposed solution.

In this paper the realization and characterization of a new plastic optical fiber sensor for the detection of H2S and other sulfide compounds is described. The sensor is specifically tailored for applications in cultural heritage preservation, where the capability to evaluate the total exposure even to small quantities of pollutants is required. The substitution of plastic for glass optical fibers accounts for the possibility of having all the advantages of a fiber-based device, while lowering the cost of the final device and furthermore improving the sensitivity for evanescent field sensing. The transducer exploits the variation of the optical absorption of Ag when exposed to the sulfide atmosphere and is fabricated by a preliminary chemical etching of the cladding in ethyl-acetate, followed by deposition of the Ag thin film by plasma sputtering. Some sensors prototypes have been developed and tested in a climatic chamber to assess their response in the presence of sulfide vapors. In addition chemical and morphological characterization of the plastic fibers have been carried out by means of infrared spectroscopy and scanning electron microscopy. The prototypes exposed to H2S have shown a very fast response achieving a 90% decay in the transmitted power in 900 seconds upon exposure to a 0.1 M H2S solution; such a decay has been found to be nearly wavelength independent, and is correlated to the transformation of the metallic Ag into Ag2S.