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A new process combining fossil fuels and solar energy to obtain synthetic liquid fuels from coal and natural gas is investigated. The aim of the work is to develop a hybrid process for the production of liquid fuels, where fossil fuels are used as feedstock and solar energy as heat source. Gasification of coal and steam reforming of natural gas have been coupled, examined, and simulated with respect to material and energy balances. The technical feasibility of the process is discussed in two different cases: a plant located in Italy (Sicily) and one in the USA (Texas). A comparison in terms of CO2 emissions is performed among the processes presently proposed, a gas to liquid (GTL) process, a coal to liquid (CTL) process, and another hybrid configuration coupling GTL and CTL, called the modified CTL process. It is shown that the CO2 produced per unit weight of liquid fuel is the minimum among all the alternatives considered, except for the GTL one, where the value is comparable. Also, the thermal efficienc...

A continuous plant specifically designed for microbial inactivation by high pressure CO 2 is presented. The pilot plant was built to check the high pressure CO 2 pasteurization method on pumpable foodstuffs in an apparatus suitable for development at industrial scale. Results are reported on both simple and complex substrates. First, model suspension with selected microbial strain as test microorganism was tested at 110 bar, 27 °C and 36 °C, then fresh foodstuffs were treated in their natural condition. The operating temperature was always between 26 and 40 °C, the pressure between 80 and 110 bar. In physiological saline solution, inoculated with Bacillus subtilis , total inactivation degree was achieved. The effectiveness of the proposed technology for food pasteurization was successfully checked at particularly mild conditions on natural grape must. The high pressure CO 2 pasteurization was effective with natural red orange juice and commercial inoculated tomato paste as well, whereas natural tomato paste proved to be resistant to the CO 2 treatment.

The production of biofuels from microalgae is associated with high demands of nutrients (nitrogen and phosphorus) required for growth. Recycling nutrients from the residual biomass is essential to obtain a sustainable production. In this work, the aqueous phase obtained from flash hydrolysis of Scenedesmus sp. was used as cultivation medium for a microalga of the same genus, to assess the feasibility of this technique for nutrient recycling purposes. Batch and continuous cultivations were carried out, to determine growth performances in this substrate compared to standard media, and verify if a stable biomass production could be obtained. In continuous experiments, the effect of hydrolysate inlet concentration and of residence time were assessed to optimize nutrient supply in relation to productivity. Results obtained show that nutrient recycling is feasible by treating biomass with flash hydrolysis, and Scenedesmus is capable of recycling large amounts of recovered nutrients.

Muscle synergies are hypothesized to represent motor modules recruited by the nervous system to flexibly perform subtasks necessary to achieve movement. Muscle synergy analysis may offer a better view of the neural structure underlying motor behaviors and how they change in motor deficits and rehabilitation.

Gasification is one of the cleanest possible ways to exploit abundant coal reservoirs all over the world to produce electricity and synthesize chemicals. Major challenges in the design of any gasification plant are desulfurization of the gases produced as a result of high sulfur contents in some coal types, removal of tar in the product gas, and costs associated with Air Separation Unit. For environmental sustenance and energy saving, an indirect gasification scheme for coal is proposed and simulated which uses steam instead of oxygen-steam mixture as the gasification medium. This avoids the need of costly air separation process, while the heat for the endothermic process is supplied by hot flue gases passing through a bayonet heat exchanger installed within the reactor vessel. Simulation is carried out using the Aspen Plus™ software integrated with an MS Excel™ spreadsheet. The simulation results show a remarkable achievement of cold gas efficiency of 70 %. The utilization of heating value of coal is optimized as the process is fully heat integrated and large amount of surplus superheated high pressure steam is generated providing for the electrical power needs of the installation. The proposed gasification scheme can be used to convert high sulfur-containing coal to fuels, chemicals and energy in areas like Thar, Pakistan, where there are an estimated 175 billion tons of coal reservoirs with sulfur content as high as 2.9 wt. %.

Abnormal motor cortex activity is common in dystonia. Cathodal transcranial direct current stimulation may alter cortical activity by decreasing excitability while anodal stimulation may increase motor learning. Previous results showed that a single session of cathodal transcranial direct current stimulation can improve symptoms in childhood dystonia. Here we performed a 5-day, sham-controlled, double-blind, crossover study, where we measured tracking and muscle overflow in a myocontrol-based task. We applied cathodal and anodal transcranial direct current stimulation (2 mA, 9 minutes per day). For cathodal transcranial direct current stimulation (7 participants), 3 subjects showed improvements whereas 2 showed worsening in overflow or tracking error. The effect size was small (about 1% of maximum voluntary contraction) and not clinically meaningful. For anodal transcranial direct current stimulation (6 participants), none showed improvement, whereas 5 showed worsening. Thus, multiday cathodal transcranial direct current stimulation reduced symptoms in some children but not to a clinically meaningful extent, whereas anodal transcranial direct current stimulation worsened symptoms. Our results do not support transcranial direct current stimulation as clinically viable for treating childhood dystonia.

All-Vanadium Redox Flow Batteries (VRFBs) are emerging as a novel technology for stationary energy storage. Numerical models are useful for exploring the potential performance of such devices, optimizing the structure and operating condition of cell stacks, and studying its interfacing to the electrical grid. A one-dimensional steady-state multiphysics model of a single VRFB, including mass, charge and momentum transport and conservation, and coupled to a kinetic model for electrochemical reactions, is first presented. This model is then extended, including reservoir equations, in order to simulate the VRFB charge and discharge dynamics. These multiphysics models are discretized by the finite element method in a commercial software package (COMSOL). Numerical results of both static and dynamic 1D models are compared to those from 2D models, with the same parameters, showing good agreement. This motivates the use of reduced models for a more efficient system simulation.

Most relevant factors influencing microalgae growth are light availability and utilization. In view of maximizing the photosynthetic efficiency of a photobioreactor, the evaluation of maintenance energy is essential to understand the energy requirement for cell growth and it is also a key parameter of most mathematical growth models. In this work, steady-state continuous experiments were carried out in a flat-bed photobioreactor, at different light intensities and irradiation regimes, measuring growth rate, productivity, lipid content, and photosynthetic efficiency of Scenedesmus obliquus at non-limiting N and P condition. Energy balance was applied to measure the maintenance term as a function of irradiation, under both continuous and simulated seasonal irradiation at middle latitudes. The energy requirement for maintenance was found to be greater under high irradiances as a result of the photoinhibition effect. Experimental data were correlated following a substrate inhibition model. The nutrient uptakes were found to depend on growth rate and light intensity and to be affected by the maintenance requirement.

Increasing concern over climate change and the impact of greenhouse gas emissions as well as diminishing global oil reserves has pushed research into alternative energy sources. Among these options, reducing the cost of microalgae cultivation, a promising source for renewable energy, is a key step in commercializing biodiesel production. Microalgae also have a two-fold advantage thanks to the capability to treat waste streams by reducing contaminants via bioremediation. In this work, the possibility of exploiting nutrients from landfill leachate was tested. Some microalgal species are able to grow in the leachate as a substrate, but the chemical composition of this waste stream often leads to growth inhibition. Thus, using strain directly isolated from the target environment could avoid problems of inhibition, in order to obtain higher biomass productivity and nutrient, i.e. pollutant, removal. Acutodesmus obliquus is a microalgal species isolated from a pond containing pretreated leachate from an urban landfill located in Lazio (Italy). This strain was cultivated in leachate from a landfill located in Istrana (TV), Italy. The leachate was diluted with distilled water and the growth of the species was measured. Several dilution ratios were tested and the maximum growth rate was obtained with 10 % of leachate in water, even though an acceptable growth was also observed with 1:2 dilution. Lipid content of about 38 – 48 % dry weight was measured. Nutrients uptake in the form of ammonia from the various leachate dilutions ranged from 30 - 97 % and, generally, it was >90 % in the case of phosphorus, which was assessed as the limiting nutrient for growth. The outcome of this work has established the real potential of utilizing ammonia-N enriched leachate as the nutrient source for yielding high lipid content algal biomass, by using native strains. Based on experimental results, preliminary calculations on photobioreactor design to treat leachate from urban landfill were carried out.

The growing penetration of renewable energy power in the electric grid has boosted the development of new technologies for stationary energy storage. All-vanadium redox flow batteries (VRFBs) exhibit a very high potential for both medium and large-scale applications. This is due to power/energy independent sizing, high efficiency, room temperature operation, and long charge/discharge cycle life. A number of challenges need to be tackled before commercialization, i.e. cell and stack design, highly efficient materials, and optimal power management and control operations [1]. Numerical models are very important for designing control and monitoring systems, which are needed for the electric grid interfacing. Both 1D and 2D finite element models have been developed in order to reduce computing cost and allow for a real-time simulation of VRFB operations [2]-[4]. In this work novel 1D steady-state and dynamic finite-element model of an all-vanadium redox flow battery are proposed. The reference cell model includes current collectors, positive and negative porous electrodes, where chemical reactions occur, and the polymer membrane for proton conduction. The FEM model incorporates the following multiphysics phenomena: momentum, charge and species conservation, mass transport (Nernst-Plank equation), electric conduction, charge generation (Butler-Volmer equation) inside the porous electrodes, and the proton conduction inside the membrane. In particular, for charge generation the effect of mass transport is taken into account by considering surface concentration of the electrolytes, which differs from bulk concentration. The VRFBs charge and discharge dynamics is taken into account by including reservoir mass balance equations. In such a way the energy storage cell performance can be properly simulated. The independent variables of the model are the electrode and electrolyte potentials and the ionic species concentrations in the porous electrodes. From potentials the overall cell voltage is derived as a function of the State of Charge (SoC) during charge and discharge cycles. The cell runtime and the storage efficiency can be deduced from the voltage time profile of the dynamic model. Numerical results of both the static and the dynamic 1D model are compared with those of 2D models, with the same parameters, showing good agreement. The proposed model is expected to be a useful tool in driving and optimizing the stack design. References [1] P. Alotto, M. Guarnieri and F. Moro, “Redox flow batteries for the storage of renewable energy: A review,” Renew. Sust. Energ. Rev., 29, (2014): 325–335. [2] C.L. Chen, H. K. Yeoh and M. H. Chakrabarti, “An enhancement to Vynnycky’s model for the all-vanadium redox flow battery,” Electrochem. Acta, 120, (2014): 167-179. [3] D. You, H. Zhang, and J. Chen, “A simple model for the vanadium redox battery,” Electrochem. Acta, 54, (2009): 6827-6836. [4] K. W. Knehr et al., “A Transient Vanadium Flow Battery Model Incorporating Vanadium Crossover and Water Transport Through the Membrane,” J. Electrochem. Soc., 159 (9), (2012): A1446-A1459.

The role of motor uncertainty in discrete or static space tasks, such as pointing tasks, has been investigated in many experiments. These studies have shown that humans hold an internal representation of intrinsic and extrinsic motor uncertainty and compensate for this variability when planning movement. The aim of this study was to investigate how humans respond to uncertainties during movement execution in a dynamic environment despite indeterminate knowledge of the outcome of actions. Additionally, the role of errors, or lack thereof, in predicting risk was examined. In the experiment, subjects completed a driving simulation game on a two-lane road. The road contained random curves so that subjects were forced to use sensory feedback to complete the task and could not rely only on motor planning. Risk was manipulated by using horizontal perturbations to create the illusion of driving on a bumpy road, thereby imposing motor uncertainty, and altering the cost function of the road. Results suggest continual responsiveness to cost and uncertainty in a dynamic task and provide evidence that subjects avoid risk even in the absence of errors. The results suggest that humans tune their statistical motor behavior based on cost, taking into account probabilities of possible outcomes in response to environmental uncertainty.

Motor speed and accuracy are both affected in childhood dystonia. Thus, deriving a speed-accuracy function is an important metric for assessing motor impairments in dystonia. Previous work in dystonia studied the speed-accuracy trade-off during point-to-point tasks. To achieve a more relevant measurement of functional abilities in dystonia, the present study investigates upper-limb kinematics and electromyographic activity of 8 children with dystonia and 8 healthy children during a trajectory-constrained child-relevant task that emulates self-feeding with a spoon and requires continuous monitoring of accuracy. The speed-accuracy trade-off is examined by changing the spoon size to create different accuracy demands. Results demonstrate that the trajectory-constrained speed-accuracy relation is present in both groups, but it is altered in dystonia in terms of increased slope and offset toward longer movement times. Findings are consistent with the hypothesis of increased signal-dependent noise in dystonia, which may partially explain the slow and variable movements observed in dystonia.

Supercritical fluid and pressurized liquid extractions are investigated for effective recovery of phenolic compounds from asparagus. By the one hand, the effect of different co-solvents on supercritical fluid extraction (SFE) is examined. Results confirm that the presence of water and ethanol is essential to obtain a phenolic enriched extract with high antioxidant activity. Operative conditions influence the extraction yield, whereas the phenolic composition of the extract does not vary significantly. By the other hand, the differences among various solvents on pressurized liquid extraction (PLE) is analysed. Once again, the mixture water–ethanol gives the best results in terms of phenolic content, which are comparable with SFE and Soxhlet ones. In total, 14 phenolic derivatives were identified, being rutin the most abundant compound in all the extracts. Phenolic acids, mainly 3-O-feruloylquinic acid, represent a relevant percentage of the phenolic content of the asparagus extracts. The methods and solvents considered influence diversely the extraction of molecules with different structure.

One of the main limitations to large-scale production of biofuels derived from microalge is the lower efficiency of sunlight conversion. The maximum theoretical value for photosynthetic efficiency is hardly achieved in real outdoor cultivation systems, mainly due to inefficient light utilization, in addition to photosaturation and photoinhibition phenomena that take place at high irradiances. This work is focused on testing different possibilities aimed at improving the overall photoconversion efficiency of microalgal production in photobioreactors. Two strategies were followed: the first one increases the portion of spectrum available for photosynthesis employing luminescent spectral-converter filters on the photobioreactor surface, the second one integrates microalgae reactors with photovoltaic panels, producing electrical energy together with biomass. Experiments were carried out both in batch and continuous laboratory scale flat-plate photobioreactors, at different light intensities and regimes, with two different species ( Nannochloropsis salina and Scenedesmus obliquus ), measuring the growth rate, pigment content, biomass concentration and photosynthetic efficiency. Results show that spectral-converters do not substantially improve the growth rate, while an integrated PV and PBR system could be a valid way to improve energy conversion performances.

The effects of CO2, CHClF2 and CH2FCF under pressure on solid lipids were addressed by high-pressure differential scanning calorimeter (HP DSC). In particular, the influence on solid–liquid and solid–solid transitions were investigated for pure tristearin and a mixture of lipids (tristearin–phosphatidylcholine–dioctyl sulfosuccinate). Both of these substances are commonly used for the production of solid–lipid–nano-particles [1] , [2] , [3] . The experiments were carried at different operating pressures up to 7.0 MPa. The melting and solidification temperatures were measured for six gas–lipid systems. Interestingly, a hysteresis was observed in the solid–liquid and liquid–solid transitions. In addition, the formation of alpha and beta polymorphisms that are typical for lipids, were found to be affected by the system pressure. With regard to the experiments with CO2, the results indicate a melting point depression as function of the gas pressure, up to 6 MPa. A similar trend to CO2 was obtained using CHClF2 at a lower pressure (0.75 MPa), however CH2FCF3 exhibits a weaker effect on the melting temperature depression compared to CHClF2. These results indicate the possibility of processing liquid lipids and similar thermosensitive compounds in gas-assisted micronization processes under mild temperature conditions.

The aim of this work is to study the effect of CO 2 under pressure on hybrid inorganic–organic polymer electrolytes, by using broad band dielectric spectroscopy (BDS) in the frequency interval 40 Hz–10 MHz and in the temperature range of −80 to 120 °C. Eleven inorganic–organic hybrid materials of the ORMOCERs type, with general formula {Al[O(CH 2 CH 2 O) 8.7 ] ρ /(LiClO 4 ) z } n were treated by applying CO 2 at 293 K and 5 MPa. The results demonstrated that the CO 2 treatment generally depressed the conductivity of about one order of magnitude. The decreased conductivity in treated complexes is explained in terms of a smaller anion-trapping ability of the Al centers. Residual CO 2 molecules are likely to inhibit the interaction of the perchlorate anions with Al centers within the structure. Segmental motion of the polymer chains plays a crucial role in the conductivity of investigated samples, while the ion-hopping phenomenon is the most important charge transfer mechanism both in the pristine and CO 2 treated materials. Equivalent conductivity studies have elucidated the different ionic species present at various salt concentrations and gave insight about the role of CO 2 in modifying the transport properties of the samples.

This study addresses some microbial inactivation phenomena induced by high pressure CO2 over micro-organisms and enzymes. The activity of four selected enzymes was measured before and after treatment with CO2 under pressure in both buffer solutions and natural cellular environment (E. coli cells and tomato paste). Results are reported for acid phosphatase, alkaline phosphatase, ATPase, and pectinase at different conditions of temperature, CO2 pressure, and treatment time (32-40 degrees C, 85-150 bar, 30-70 min). The results obtained show that the high pressure CO2 treatment induces an inactivation of cellular enzymatic activity higher than the one caused on the same enzymes in solution. However, the measured activity difference is not caused by a damage at the enzymes molecular level but is a consequence of the permeabilization of the cellular envelopes which leads to a release of unmodified enzymes from the cells with simultaneous drop of enzymatic cellular activity. The reported data suggest that the bacterial cell death is probably due not to a selective effect of high pressure CO2 treatment but to simultaneous detrimental action of CO2 on cellular membrane and cell wall.

High-pressure CO2 absorption into polymers was measured by a gravimetric method. The amount of CO2 absorbed in the polymer was extrapolated using the CO2 release profile from polymeric samples measured at standard conditions by an external balance. The polymers studied were poly-(methyl methacrylate) (PMMA) and poly(lactic-co-glycolic acid) (PLGA) with different molecular weights (MW) and lactide–glycolide copolymer ratios. Experimental results for PMMA well agree with literature data of Wissinger and Paulaitis [J. Polym. Sci.: Part B: Polym. Phys. 25 (1987) 2497] and Chang et al. [J. Supercrit. Fluids 13 (1998) 113]. For PLGA, CO2 absorption measurements were performed at 313 K and in the pressure range 0.6–4.0 MPa. The method gave reproducible results within the accuracy of ±0.002 for mass fraction, ±0.1 MPa for pressure and ±0.15 K for temperature. A perturbed-hard-sphere-chain equation of state (PHSC EOS) was used to correlate CO2–PLGA absorption isotherms. Pure EOS parameters were estimated by a group contribution method, whereas only one interaction parameter was necessary to fit the measured data. The model fairly describes the experimental data points for all PLGAs considered in this work. These results may be very useful to examine the possibility of successfully using a biodegradable amorphous PLGA polymer for developing effective pharmaceutical products by high-pressure CO2 techniques.

The use of CO2 under pressure (dense CO2) is one of the most promising techniques to achieve cold pasteurization and/or sterilization of liquid and solid materials, and is likely to replace or partially substitute currently and widely applied thermal processes. Although the ability of CO2 to inactivate microorganisms has been known since the 1950's, only within the last 15 years it has received special attention, and the scientific and economic interest towards practical applications is presently growing more and more. Here we collect and discuss the relevant current knowledge about the potentials of dense CO2 as a non-thermal technology in the field of microbial inactivation. We summarize the state of the art, including definitions, description of the equipment, relevant applications, in both simple suspensions and complex media, for the treatment of a wide range of microorganisms in both liquid and solid substrates. Finally, we also summarize and discuss the different hypotheses about the mechanisms of inactivation © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng84: 627–638, 2003.

Bacillus subtilis spores were suspended in saline solution (107 cfu/ml) and treated by both conventional heating and CO2 batch treatment at an operating pressure in the range of 70–150 bar under identical temperature conditions. Temperatures tested were in the range of 36–75 °C. Survival curves indicated significantly higher lethality when spores were treated with supercritical CO2 (SC-CO2) rather than with heating alone. These results appear particularly evident at 60 °C, a temperature at which conventional heating gave no spore-inactivation after a treating time as long as 24 h, whereas a 6 h SC-CO2 treatment led to complete sterilization. At 75 °C spores were partially killed with conventional heating but a treatment of 2 with SC-CO2 hours assured total inactivation. It is concluded that spore-inactivation during SC-CO2 treatment was only in part due to thermal effect (at the higher temperature of 75 °C) and there was a significant additional effect caused by CO2 penetration inside the latent bacteria forms.

An original experimental setup based on UV-vis spectroscopy was developed to study the precipitation kinetics of a biodegradable polymer by gas antisolvent processes (GAS). Po(v(L-lactide) acid (PLA) precipitations were carried out in a high-pressure optical cell equipped with sapphire windows, working at 1-80 bar and 301.15 - 307.15 K The particle formation and precipitation kinetics were investigated in situ by measuring UV-vis absorbance of polymeric particles at a wavelength of 600 nm. They were measured in a batch system at different pressurization rates (different supersaturation conditions). To rationalize the precipitation kinetics in GAS processes, a population balance model was developed considering particle nucleation, growth, aggregation, and settling. Nucleation and growth were represented by the McCabe model, whereas both independent- and nonindependent-kemel Smoluchowski's coagulation equations were used for aggregation. Settling was approximated by a first-order kinetic. Absorbance measurements were related to the second moment of the simulated particle-size distribution, and the kinetic parameters were estimated based on spectroscopic data. The model gave a correct phenomenological representation of all experimental data and fairly predicted the particle-size distribution of the precipitated PLA microparticles.

In this work, a new thermodynamic method, based on the McMillan–Mayer solution theory, is proposed to interpret and predict the solubility of low- and high-molecular-weight compounds in compressed CO2. In the thermodynamic approach presented here, the solute is referred to as a pseudo pure component while the compressed CO2 is represented as a continuous medium that affects the interactions among solute molecules. The perturbed-hard-sphere-chain (PHSC) theory is used within the McMillan–Mayer framework to derive an expression for the repulsive and attractive contributions to the Helmholtz free energy of the solute. While easy to handle, the model enlightens the effects of molecular weight and other physical–chemical characteristics on compounds solubility in compressed media. The thermodynamic approach fairly describes the experimental data concerning the solubility of several substances in compressed CO2 at different temperatures. The model also predicts CO2 solubility in PEG polymer and semi-quantitatively reproduces high-molecular-weight component solubility in compressed CO2 containing low amount of ethanol as co-solvent.

In this work UV−vis spectroscopy is used to measure in situ the volume expansion of the saturated liquid phase during gas−antisolvent (GAS) processes with compressed CO2. The technique involves the use of two internal standards: potassium hexacyanoferrate(III) is used for polar solvents, and ferrocene for nonpolar solvents. The absorbance peaks of the reference substances are used to determine the volume expansion of the saturated liquid phase. Measurements on the dimethyl sulfoxide + CO2, dioxane + CO2, and dimethyl sulfoxide + water + CO2 systems have been made in the temperature range from 298 to 313 K and for pressures up to 70 bar. The experimental results obtained compare well with available literature data.

High-pressure treatments are receiving a great deal of attention for the inactivation of micro-organisms in foodstuff processing, pressure instead of temperature is used as stabilizing factor. In this context, high hydrostatic pressure treatment is the most studied alternative process, many works reported successful results in inactivating a wide range of micro-organisms under different operative conditions such as temperature, cycles of pressure, exposure time. Furthermore, a number of processes using high pressure treatment (HPT) has already been put into the market. Nevertheless this new technology presents the main limitation to be very expensive and difficult to control and manage because of the extremely high pressure employed, so that the widespread industrial diffusion in industry field appears cumbersome. The treatment with supercritical CO 2 could become a relevant alternative to HPT in the field of microbial inactivation of food as well as an innovative technique for the sterilization of thermally and hydrolytically sensitive polymeric materials in biomedical applications, such as polymeric particles for drug delivery or polymeric implants. It has been demonstrated that the effect of microbial inactivation assuring healthy food preservation is already consistent at pressures moderated (lower than 200 bar) when compared with those employed by traditional hydrostatic-pressure HPT methods (2000–7000 bar). In this work the anti-microbial potential of compressed CO 2 was investigated against gram-negative bacteria, gram-positive bacteria and spores; as model species, Pseudomonas aeruginosa , Bacillus subtilis and spores of B. subtilis were used. The experiments were performed in a semi-continous apparatus at different but mild operative conditions. Excellent results were obtained for micro-organisms, under appropriate conditions the survival ratio of bacteria could be reduced to about seven orders of magnitude. Inactivation of spores under the same conditions, found to be conflicting in open literature, was not satisfactory. Spore inactivation was possible by coupling combination of higher temperature and longer contact time conditions. The application of pressure cycles was also found to be beneficial.

In this paper, acidic hydrolysis (0–5 vol%) was performed on Chlorella vulgaris biomass using a range of temperature (100–130 °C) and reaction time (0–60 min) with high biomass load (10%—100 g L−1), in order to characterize the kinetic of biomass solubilization, hydrolysis of sugars, proteins and ash release, and to verify the main divergences and similarities in relation to lignocellulosic biomass. More than 90% of the sugars present in the biomass was hydrolyzed and later satisfactorily fermented by S. cerevisiae. The inclusion of acid concentration in the kinetic model for biomass solubilization and sugar hydrolysis led to a modified Michaelis–Menten equation able to simulate efficiently the acidic extraction/hydrolysis data of all experimental runs. Main divergences in relation to lignocellulosics were related to higher reaction order and lower activation energy, reveling better susceptibility of microalgal biomass to acidic treatment. The proposed process is promising and can be easily scaled up at industrial level.

Background Even if movement abnormalities in dystonia are obvious on observation-based examinations, objective measures to characterize dystonia and to gain insights into its pathophysiology are still strongly needed. We hypothesize that motor abnormalities in childhood dystonia are partially due to the inability to suppress involuntary variable muscle activity irrelevant to the achievement of the desired motor task, resulting in the superposition of unwanted motion components on the desired movement. However, it is difficult to separate and quantify appropriate and inappropriate motor signals combined in the same muscle, especially during movement. Methods We devise an innovative and practical method to objectively measure movement abnormalities during the performance of a continuous figure-eight writing task in 7 children with dystonia and 9 age-matched healthy controls. During the execution of a continuous writing task, muscle contractions should occur at frequencies that match the frequencies of the writing outcome. We compare the power spectra of kinematic trajectories and electromyographic signals of 8 upper limb muscles to separate muscle activity with the same frequency content of the figure-eight movement (task-correlated) from activity occurring at frequencies extraneous to the task (task-uncorrelated). Results Children with dystonia present a greater magnitude of task-uncorrelated muscle components. The motor performance achieved by children with dystonia is characterized by an overall lower quality, with high spatial and temporal variability and an altered trade-off between speed and accuracy. Conclusions Findings are consistent with the hypothesis that, in childhood dystonia, the ability to appropriately suppress variable and uncorrelated elements of movement is impaired. Here we present a proof-of-concept of a promising tool to characterize the phenomenology of movement disorders and to inform the design of neurorehabilitation therapies., Journal of NeuroEngineering and Rehabilitation, 12, ISSN:1743-0003

Childhood dystonia is a movement disorder characterized by involuntary sustained or intermittent muscle contractions causing twisting and repetitive movements, abnormal postures, or both (Sanger et al, 2003). Dystonia is a devastating neurological condition that prevents the acquisition of normal motor skills during critical periods of development in children. Moreover, it is particularly debilitating in children when dystonia affects the upper extremities such that learning and consolidation of common daily motor actions are impeded. Thus, the treatment and rehabilitation of dystonia is a challenge that continuously requires exploration of novel interventions. This review will initially describe the underlying neurophysiological mechanisms of the motor impairments found in childhood dystonia followed by the clinical measurement tools that are available to document the presence and severity of symptoms. Finally, we will discuss the state-of-the-art of therapeutic options for childhood dystonia, with particular emphasis on emergent and innovative strategies.

In view of an efficient industrial autotrophic cultivation of microalgal biomass, the role of light into photobioreactor is still to be fully ascertained. The influence of different light intensities was investigated using both continuous illumination and alternation of light and dark cycles with different frequencies, which mimic illumination variations in a photobioreactor due to mixing. In order to minimize the effect of cell self- shading all experiments were carried out in thin layer flat plate reactor (which can be operated both in batch and continuous mode), where microalgae were cultivated under a non-limiting CO2 supply, with CO2- enriched air bubbled through the culture. In this apparatus, we measured growth rate, lipid content and photosynthetic performances of Scenedesmus obliquus. The species showed a maximum growth rate at about 150 µmol of photons m-2 s-1. Above this value the growth was inhibited, while the algae was found still able to exploit light, even if at lower efficiency, and showed a decreased pigment content. The resistance of the species to high irradiances was confirmed also in continuous experiments, where microalgae were found able to adapt to high illumination, leading to an increased steady state concentration and higher productivity at 350 µmol m-2 s-1 (about 3 g L-1 d-1). In addition, by changing the residence time, a maximum in productivity was found. The lipid content, constitutively high, was not affected by the variation light intensity, making this species suitable to industrial application. Furthermore, the alternation of light and dark cycles with different frequencies was studied both in batch and continuous experiments. Cultures exposed to pulsed light shows a drastically reduced growth compared to continuous light.

In the last years new renewable energy sources started to be exploited to compensate exhausting fossil fuels and minimize anthropogenic factors on climate change. Microalgae have reemerged as potential next-generation feedstock for biofuels and they are considered very promising on the long term, since they have a potentially high productivity per area and they can be grown on marginal land without competing with food crops. Our work is focused on the seawater microalga Nannochloropsis gaditana, which combines a fast growth rate with a strong accumulation of lipids and therefore yields great potential for these kinds of applications. Solar radiation provides all the energy supporting algae growth and lipids production and for this reason the available radiation must be exploited with the highest possible efficiency to optimize productivity and make their cultivation on a large scale competitive. Investigation of the bases affecting light use efficiency is thus seminal to elucidate the connection between light and the lipids/biomass productivity. To this aim we investigated the influence of different illumination regimes, nutrients availability and batch/ continuous cultivation on N. gaditana cultures productivity and light use efficiency. This information will be exploited for optimization of growing systems but also to design Nannochloropsis gaditana genetic manipulations. Strains with altered composition of the photosynthetic apparatus and modified regulation of photosynthesis are being selected and characterized to increase Nannochloropsis gaditana productivity in photobioreactors.

Background Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is a treatment for severe childhood-onset dystonia. A common challenge for clinicians is determining which contacts of the DBS electrode to stimulate in order to provide maximum future benefit to the patient. Objective To characterize how the cortical responses to DBS relate to stimulation parameters (i.e. electrode contacts, voltage, and pulse width) and clinical outcomes. Methods We examined 11 patients with dystonia undergoing DBS therapy (9–21 years old when implanted). We varied the active contacts, voltage, and pulse width of the stimulating electrode and analyzed the deep-brain stimulator evoked potentials (DBSEPs) measured with electroencephalogram, and assessed symptoms with the Barry-Albright dystonia scale. Statistical tests included: Repeated measures ANOVA, Mann–Whitney U test and paired t -test. Results DBSEPs near sensorimotor areas were larger ipsilaterally than contralaterally ( P = 0.007). The rate of DBSEP amplitude increase with respect to stimulator voltage (voltage gain) and pulse width (pulse width gain) varied across subjects and stimulating contacts. Voltage gains were significantly higher among patients who showed larger improvements with DBS ( P = 0.038). Additionally, a within-subject comparison of all patients showed that voltage gains were higher for contacts chosen for chronic stimulation as compared to those that were not ( P = 0.007). Conclusions DBSEPs may be good predictors of therapeutic response to stimulation at different electrode contacts. Furthermore, effective DBS therapy appears to modulate sensorimotor cortex. These findings may help clinicians optimize stimulator programming and may eventually lead to improved targeting during implantation.

Microalgae as source of energy have generated an enormous interest in the last decades. Microalgae seem to be the most feasible option to obtain renewable liquid fuels due to high growth rates, CO2 fixation capability and large accumulation of oil compared to other crop plants. The bottleneck of this technology is anyway represented by the costs of the process, both from the economic and energetic points of view. In order to reduce the energetic costs and to make microalgae cultivation more attractive, the possibility of exploiting the energetic content of microalgal biomass residues after oil extraction by means of anaerobic digestion to produce biogas was studied. Two microalgal species, Scenedesmus obliquus and Chlorella protothecoides, selected for their high oil contents and fast growth rates, were tested for biogas production, before and after the oil extraction. Oil extraction was carried out by Soxhlet method, using a mixture of methanol and chloroform as the solvent. Biochemical Methane Potential (BMP) tests were carried out to evaluate biogas production capacity from microalgae and degradability rates. Two different kinds of inocula were used to compare the specific hydrolytic capacities and to assess the most suitable one to maximize the biogas conversion of microalgae. The digestion tests were performed at controlled temperature of 37 °C, in batch reactors. Production of biogas and the proportion of CO2 and CH4 content were measured. The results are discussed in view of feasible industrial application.

One of the main parameters influencing microalgae production is light, which provides energy to support metabolism but, if present in excess, can lead to oxidative stress and growth inhibition. In this work, the influence of illumination on Scenedesmus obliquus growth was assessed by cultivating cells at different light intensities in a flat plate photobioreactor. S. obliquus showed a maximum growth rate at 150 μmol photons m(-2) s(-1). Below this value, light was limiting for growth, while with more intense illumination photosaturation effects were observed, although cells still showed the ability to duplicate. Looking at the biochemical composition, light affected the pigment contents only while carbohydrate, lipid, and protein contents remained stable. By considering that in industrial photobioreactors microalgae cells are subjected to light-dark cycles due to mixing, algae were also grown under pulsed illumination (5, 10, and 15 Hz). Interestingly, the ability to exploit pulsed light with good efficiency required a pre-acclimation to the same conditions, suggesting the presence of a biological response to these conditions.

Dystonia has been associated with injury to the basal ganglia, in particular to the putamen and globus pallidus, even if there is evidence that other brain areas including cerebellum, brainstem, or sensory cortex can be causes of dystonia. Although dystonia is regarded as a movement disorders, several sensory phenomena occur. This suggests a dysfunction ascribable to a defective central processing of sensory inputs leading to a distorted afferent information causing a fixed input-output mismatch in specific motor programs. Still little is known about the altered sensorimotor integration in dystonia, therefore the need for a deeper investigation and for optimal complementary treatments is strong. We propose the use of the biofeedback technique as an exploratory tool and a possible future rehabilitation instrument. In this framework, the aim of our study is to investigate, in children with dystonia, the ability to voluntarily and selectively control the activation of a target muscle at different levels of the upper limb kinematic chain by means of a EMG-based vibro-tactile biofeedback. These tests should shed light on how an additional proprioceptive information affects the motor outcome in dystonia compared to the healthy behavior, both in kinematic and electromyographic quantitative terms.

The exploitation of microalgae in a wastewater treatment process is currently an open issue, and its actual applicability is still under investigation. In this work the effects of temperature, day/night irradiation and bacterial competition were studied on growth and nutrient removal of Chlorella protothecoides cultivated in real and unsterilized primary urban wastewater. C. protothecoides showed a linear dependence of growth rate on temperature under continuous irradiation with a maximum at 30 °C. Continuous flow experiment under day–night irradiation condition showed that a cyclic steady state was achieved, with significant differences in biomass concentration and nutrient removal after dark and light periods. The presence of a native microflora in wastewater did not affect the microalgal growth, both in batch and continuous flow experiments. N and P were efficiently removed in all conditions tested, while the COD was not consumed by microalgal biomass. Thus, in view of a large scale application, a two step depuration process would be required, where the photobioreactor will remove nutrients as N and P and an activated sludge reactor downstream will reduce the organic matter. The experimental data obtained were used to design a possible process of this type.

Supercritical CO2 extraction from microalgae is applied with the aim of obtaining an oil rich in α-linolenic (ALA) essential fatty acid and with a low ω6:ω3 ratio. The maximum extraction yield is obtained at 60 °C and 30 MPa with 0.4 kg/h of CO2 and 5% of co-solvent (ethanol). When the effect of pressure, temperature and density on the supercritical extraction yield and solubility are studied, the thermodynamic cross-over is found at a pressure close to 30 MPa, while the extraction cross-over occurs at around 25 MPa. The experimental solubility data are correlated by literature empirical models. Mathematical models developed by Sovova are applied to describe the experimental extraction curves. Soxhlet extraction of lipids is also carried out, obtaining a similar fatty acids profile but proving to be less selective than SCCO2 method. Among the three species of microalgae examined, results show that Scenedesmus obliquus oil is richer in ω-3 fatty acids and ALA than Chlorella protothecoides and Nannochloropsis salina lipids. The effect of the extraction parameters on ALA content and the fatty acid profile is also analysed, concluding that the ω-3 percentage is favoured by lower temperatures, lower pressures and shorter extraction times.

Inactivation kinetics of Escherichia coli spiked on fresh cut carrot and exposed to high pressure carbon dioxide (HPCD) treatment at several conditions of pressure (6, 8, 10, and 12 MPa) and two conditions of temperature (26 and 35 °C) were obtained as a function of the treatment time (up to 30 min). The Weibull model was applied to fit the inactivation kinetics and calculate δ and n model parameters for each pressure and temperature. The results demonstrated that the model was able to fit with good agreement the inactivation curves (high R 2 and low RMSE values). In a second attempt, the model parameters were correlated with CO 2 density resulting in a linear relationship. Validation of the proposed model was also performed at 6.6 and 10 MPa, 26 °C and at 8 MPa, 35 °C providing log reduction residual values (observed value–predicted value) lower than 0.50 and showing a good agreement between the experimental and the predicted inactivation data. The model proved to be a powerful tool to fit and predict, in the proposed operative range, the inactivation kinetics of E. coli spiked on fresh cut carrot treated by HPCD. The results demonstrated the potential of a relative simple correlative model for the interpretation of the inactivation data and for HPCD process design and optimization.

Drug-loaded polymers and polymeric microparticles provide an attractive form for controlled drug-delivery systems. Design of new systems requires knowledge of polymer–drug interactions. The effect of polymer architecture and chemistry upon active-ingredient loading is investigated by Monte Carlo simulation. The ensemble-growth method is used to sample conformations of a model polymer comprising polar and nonpolar segments. The polymer is a block copolymer, linear or branched. In our calculations, the polar portion of the polymer contains 21 segments. The polymers are dissolved in either of two types of solvent models. In the first, nonpolar solvent, the polar segments tend to collapse, but the bulky nonpolar groups, easily soluble in the medium, create some cavities in the polymer. These cavities are suitable hosts for the slightly polar active ingredient. In the second solvent, polar, the nonpolar segments contribute to attract the active ingredient within the polymer segments, therefore lowering the burst-release rate. The relative uptake of the active ingredient, proportional to the probability of finding an active ingredient within the radius of gyration of the polymer, is computed as a function of the number of nonpolar segments in the polymer. Simulation results are reported for active ingredients of two different sizes. For given size of the polar portion, short nonpolar tails increase the active-ingredient relative uptake in both solvents considered. Linear block copolymers look promising for obtaining higher entrapment efficiency for the active ingredient and for controlled release.

Artificial neural networks (ANNs) have been employed for the inversion of the geometrical parameters of a magma-filled dike, which causes observable changes in various geophysical fields. The inversion approach, which is based on the function approximation capabilities of multilayer perceptrons (MLPs), is also carried out by a systematic search technique based on the simulated annealing (SA) optimization algorithm in order to emphasize the merits of the proposed strategy. It is shown that even if the SA approach guarantees a high degree of accuracy, it requires a considerable amount of time, incompatible with on-line applications. On the other hand, it is shown that MLPs, once correctly trained, can solve the inversion problem very fast and with an appreciable degree of accuracy. It is also demonstrated that an integrated approach involving geophysical data of different kinds allows for a more accurate solution than when ground deformation data alone is considered. The results given in the paper are supported by experiments carried out using an interactive software tool developed ad hoc, which allows both direct and inverse modeling of data related to the opening of a crack at the beginning and throughout a volcanic activity episode.

Toward improved understanding of the dilute-solution properties of arborescent polystyrenes, new measurements are reported for osmotic second virial coefficients and for intrinsic viscosities in three common organic solvents. As observed for other branched polymers, branching decreases the second virial coefficient in good solvents and lowers the theta temperature for a polymer–solvent system. For generation-zero arborescent polystyrene in methylcyclohexane, the theta temperature is 36±2°C. A correspondence between intrinsic viscosity and second virial coefficient, valid for hard-spheres solutions, holds in good solvents; this correspondence improves with decreasing branch molecular weight. The osmotic-pressure data are interpreted with a colloid-like thermodynamic framework using a van der Waals-type equation of state. The reference state is the hard sphere and the perturbation is given by an attraction decaying with the sixth power of the center-to-center distance between polymers. The hard-sphere diameter is obtained from intrinsic-viscosity data. Predicted and observed osmotic pressures are in good agreement.

In view of developing new drug-delivery systems, microparticles of biocompatible polymer loaded with protein were produced using a supercritical antisolvent technique. As the polymer, poly(lactic acid) (PLA) of about 100 000 Da was used, whereas insulin was chosen as the protein model. To achieve microencapsulation, we started from a homogeneous solution of protein and polymer, to which the supercritical antisolvent is added; mixtures of dichloromethane and dimethyl sulfoxide were used to ensure the solubility of both the polymer and the protein. All experiments were performed in semicontinuous mode. A preliminary study with PLA alone was done in order to select the best operative condition and to control the particle dimension and their diameter distribution range, especially with mixtures of the two solvents. Then, the microspheres of PLA charged with insulin were produced; the average diameters ranged from 0.5 to 2 μm. The composition of these particles was determined analytically, and the protein bioa...