Simultaneous detection of transgenic DNA by surface plasmon resonance imaging with potential application to gene doping detection

Surface plasmon resonance imaging (SPRi) was used as the transduction principle for the development of optical-based sensing for transgenes detection in human cell lines. The objective was to develop a multianalyte, label-free, and real-time approach for DNA sequences that are identified as markers of transgenosis events. The strategy exploits SPRi sensing to detect the transgenic event by targeting selected marker sequences, which are present on shuttle vector backbone used to carry out the transfection of human embryonic kidney (HEK) cell lines. Here, we identified DNA sequences belonging to the Cytomegalovirus promoter and the Enhanced Green Fluorescent Protein gene. System development is discussed in terms of probe efficiency and influence of secondary structures on biorecognition reaction on sensor; moreover, optimization of PCR samples pretreatment was carried out to allow hybridization on biosensor, together with an approach to increase SPRi signals by in situ mass enhancement. Real-time PCR was also employed as reference technique for marker sequences detection on human HEK cells. We can foresee that the developed system may have potential applications in the field of antidoping research focused on the so-called gene doping.     

Corrosion behavior of Cu–SiO<Subscript>2</Subscript> nanocomposite coatings obtained by electrodeposition in the presence of cetyl trimethyl ammonium bromide

Copper silica composite coatings are an attractive alternative to chromium and nickel coatings in order to avoid environmental problems and for application in electrical devices. However, co-deposition of SiO₂ particles with metals occurs to a rather limited extent, generally under 1%, due to the hydrophilicity of SiO₂, which makes the incorporation of particles in a metallic matrix difficult. To overcome this drawback, the influence of cetyl trimethyl ammonium bromide (CTAB) on the deposition and corrosion behavior of Cu–SiO₂ coatings on steel has been studied. It was established that CTAB plays a beneficial role in SiO₂ suspension stabilization, promotes the co-deposition of nanoparticles in the copper matrix and improves the deposit morphology and structure. Consequently, a higher corrosion resistance of Cu–SiO₂ deposits obtained in the presence of CTAB was noticed. The most important effect was observed in the case when CTAB was used in concentration of 10⁻³ M in the electroplating bath.     

Comparison of conventional extraction under reflux conditions and microwave-assisted extraction of oil from popcorn.

Popcorn offers an environmentally friendly alternative to the commercial synthetic loose-fill packing materials. Popcorn could be used for cushioning purposes if the oil is extracted after the popping process. Conventional and microwave-assisted extraction methods were used for oil extraction from whole and ground, popped and unpopped kernels. The conventional extraction method achieved 68.5% oil recovery from whole popped kernels. However, whole unpopped kernels were not efficiently de-oiled with either of the methods. Extraction of oil from popped kernels is recommended; corn varieties with higher starch content and lower oil content should be used.     

Synthesis,characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers

Copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with methyl methacrylate and styrene were synthesized in benzene at 85 °C in the presence of 2,2′‐azobisisobutyronitrile as initiator. The structure of the resulting copolymers was investigated and a polymerization mechanism was proposed. The intrinsic viscosity of the copolymers in dilute solutions of carbon tetrachloride was determined as a function of temperature and conformational transitions were investigated. Copyright © 2004 Society of Chemical Industry     

Polycondensation of tetrachlorobisphenol a with chloromethylphosphonic dichloride. 1H-NMR kinetic study

The temperature-programmed polycondensation of tetrachlorobisphenol A with chloromethylphosphonic dichloride is carried out in the sample tube of an NMR spectrometer. From the spectra during polycondensation, the instantaneous concentration of components can be determined. Phosphorus and chlorine-containing polymers with flame-retardant properties are obtained.     

Restarts and exponential acceleration of the Davis-Putnam-Loveland-Logemann algorithm: A large deviation analysis of the generalized unit clause heuristic for random 3-SAT

An analysis of the hardness of resolution of random 3-SAT instances using the Davis-Putnam-Loveland-Logemann (DPLL) algorithm slightly below threshold is presented. While finding a solution for such instances demands exponential effort with high probability, we show that an exponentially small fraction of resolutions require a computation scaling linearly in the size of the instance only. We compute analytically this exponentially small probability of easy resolutions from a large deviation analysis of DPLL with the Generalized Unit Clause search heuristic, and show that the corresponding exponent is smaller (in absolute value) than the growth exponent of the typical resolution time. Our study therefore gives some quantitative basis to heuristic restart solving procedures, and suggests a natural cut-off cost (the size of the instance) for the restart.     

Biosorption of protons and heavy metals onto olive pomace: modelling of competition effects

Heavy metal biosorption onto solid wastes from olive oil production plants, olive pomace, has been investigated. Acid-base properties of the active sites of olive pomace were determined by potentiometric titrations and represented by a continuous model accounting for two main kinds of active sites. Competition among protons and heavy metals in solution was considered by performing biosorption tests at different equilibrium pH with single (Cu and Cd) and binary metal systems (Cu-Cd). Both Langmuir extensions and non-ideal competitive adsorption models (NICA models) can be used to represent experimental data of Cu and Cd biosorption in single metal systems at different equilibrium pH. Nevertheless only NICA models, accounting for site heterogeneity and non-ideal adsorption of the different species simultaneously present in solution, can adequately simulate the competition among Cu and Cd in binary metal systems by using the parameters fitted to single system data.     

Storage-time effects on olive oil DNA assessed by Amplified Fragments Length Polymorphisms

In this study Amplified Fragments Length Polymorphisms (AFLPs) analysis was applied on DNA extracted from different monovarietal olive oils. The aim was to study how the length of storage after milling of the oil can affect the use of DNA as an analyte for molecular traceability. Results, all assessed by statistical analyses, showed that the authentication of olive oil with molecular methods should be performed within a month from olive oil production. After this period, a significant decrease of quality of DNA extracted from olive oil was observed, with a consequent loss of information, that can affect the reliability of the results.     

Supercritical carbon dioxide-treated blood orange juice as a new product in the fresh fruit juice market

The work described here deals with the effectiveness of using high-pressure carbon dioxide treatment (HPCD) to stabilise freshly squeezed blood orange juice. Technical planning of a continuous high-pressure supercritical carbon dioxide pilot system, suitable for development on an industrial scale, was carried out in our lab. To determine the optimal operating conditions (temperature, pressure, and CO₂/juice ratio), three different experimental trials were carried out. The first trial was conducted at 230 bar, 36 ± 1 °C, 5.08 L/h juice flow rate, and 3.91 L/h CO₂ flow rate, corresponding to a g_CO2/g_juice ratio of 0.770. The second trial utilised the same conditions except that the operative pressure was reduced (130 bar). The third trial was carried out at 130 bar, 36 ± 1 °C, 5.08 L/h juice flow rate, 1.96 L/h CO₂ flow rate, corresponding to a 0.385 g_CO2/g_juice ratio. The effects of processing were evaluated by determining physicochemical, antioxidant, and microbiological parameters of the treated juices. In addition, once the best operative parameters had been determined, physicochemical, antioxidant, microbiological and sensory evaluation of fresh blood orange juice stabilised by HPCD treatment was carried out during refrigerated storage of juices at 4 ± 1 °C for thirty days. The results showed that HPCD treatment cannot be considered as an alternative to traditional thermal methods but as a new mild technology for producing a stabilised blood orange juice with a shelf-life of 20 days.Industrial relevanceBlood oranges are the main cultivated varieties of Citrus sinensis (L.) Osbeck in Italy. Freshly squeezed blood orange juice exert a high antiradical and antioxidant activity, due to its rich phenolic profile, but its preservation is usually assured by thermal treatment which affects its nutritional and sensory value. In this study we proposed a “milder” continuous HPCD process suitable for implementation on an industrial scale. The HPCD stabilised juice retains its physicochemical, antioxidant, and sensory properties and could be placed within a new retail framework, namely, that of fresh juices with a shelf-life of 20 days.