Functional properties of subunit interactions in human cytidine deaminase

An intersubunit interactions study related to the active sitehas been performed on the wild-type cytidine deaminase (CDA)and on the mutant enzyme F137W/W113F. F137 is the homologousto the Bacillus subtilis CDA F125 involved in the subunit interactions.In the presence of SDS, wild-type human CDA dissociates intoenzymatically inactive monomers without intermediate forms viaa non-cooperative transition. Extensive dialysis or dilutionof the inactivated monomers restores completely the activity.Circular dichroism measurements show that the secondary/tertiarystructure organization of each subunit is unaffected by theSDS concentration, while the mutation Phe/Trp causes weakeningin quaternary structure. The presence of the strong human CDAcompetitive inhibitor 5-fluorozebularine disfavours dissociationof the tetramer into subunits in the wild-type CDA, but notin mutant enzyme F137W/W113F. The absence of tyrosine fluorescenceand the much higher quantum yield of the double mutant proteinspectrum suggest the occurrence of an energy transfer effectbetween the protein subunits. This assumption is confirmed bythe crystallographic studies on B.subtilis in which it is shownthat three different subunits concur with the formation of eachof the four active sites and that F125, homologous to the humanCDA F137, is located at the interface between two differentsubunits contributing to the formation of active site. Received February 10, 2003; revised October 14, 2003;; accepted October 21, 2003     

Functional cortico-muscular coupling during upright standing in athletes and nonathletes: A coherence electroencephalographic-electromyographic study.

We tested the hypothesis that functional cortico-muscular coupling of brain rhythms is implied in the control of lower limb muscles for upright standing. Electroencephalographic (EEG; Be-plus Eb-Neuro) and electromyographic (EMG) data were recorded in 18 fencing and 19 karate elite athletes, 14 karate amateurs, and 9 non-athletes, during quiet upright standing with open and closed eyes conditions. Cortico-muscular coupling was evaluated by computing EEG-EMG spectral coherence and directed transfer function (DTF). Body sway area did not differ among the groups. In non-athletes, the EEG-EMG coherence (gastrocnemius lateralis) at centro-parietal and parasylvian alpha rhythms (about 8-12 Hz) was higher during the open than closed eyes condition. This was not true in the elite athletes. At the same alpha rhythms, the sport amateurs presented values halfway between the non-athletes and elite athletes. Finally, the DTF was higher for cortico-muscular than muscular-cortical direction. These results suggest that visual information affects cortico-muscular coherence at 8-12 Hz in non-athletes and amateur athletes but not in elite athletes. In elite athletes, this might be due to a long training for the control of equilibrium based on proprioceptive and tactile inputs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design of a hybrid electric fuel cell power train for an urban bus

With the requirements for reducing emissions and improving fuel economy, new markets have become attractive for automotive companies that are developing electric, hybrid, and plug-in vehicles using new technologies candidates to be implemented in the next generations of vehicles. Most of all, hybrid vehicles are attracting interest due to great potential to achieve higher fuel economy and a longer range with respect to pure electric mode but often this solution is not petroleum free. Within a national project CNR TAE Institute is involved in the development of a zero emission hybrid electric city bus based on PEM fuel cell technology able to increase the range at least 30% with respect to the same vehicle in pure electric configuration. Design, control and preliminary results are reported in this paper.     

Coupling and thermal integration of a solid oxide fuel cell with a magnesium hydride tank

A solid oxide fuel cell (SOFC) based combined heat and power (CHP) system in the power range of 1 kWe fed by pure hydrogen stored in a MgH₂ tank thermally integrated with the SOFC is presented. Different system configurations were first simulated to compare the system performances in each case. An experimental setup specially designed to test the thermal integration of a magnesium hydride tank with a 1 kWe SOFC stack is fully described. The difficulties encountered during the coupling tests are useful to understand how to solve these technical issues.     

A Review on Agri-food Supply Chain Traceability by Means of RFID Technology

Radio Frequency Identification (RFID) is a technology which provides appealing opportunities to improve the management of information flow within the supply chain and security in the agri-food sector. Nowadays, food safety is considered a major requirement in several countries, in particular, the traceability of food products which is mandatory by law. Thus, technological implementation leading to traceability strengthening in the agri-food sector is crucial. The first aim of this review is to analyze the current developments in RFID technology in the agri-food sector, through an operative framework which organizes the literature and facilitate a quick content analysis identifying future research direction. RFID technology seems to be able to bring great opportunities to this sector; nevertheless, several constraints are slowing its adoption. This survey may provide readers with an exhaustive overview of opportunities and constraints for the wide adoption of RFID. The second aim of this review is to provide an updated analysis on the current developments of RFID technology for different product typologies within the agri-food industry, discussing at the same time its potential in technological and logistical development regarding different sectors of the production/distribution chain. As referenced here, RFID implementations in the agri-food sector are increasing at a fast rate, and technological advancement follows the applicability opportunities. However, real applications of RFID technologies are still limited because of various technical and economical obstacles which are also discussed.     

Renewable energy for hydrogen production and sustainable urban mobility

In recent years, the number of power plants based on renewable energy (RWE) has been increasing and hydrogen as an energy carrier has become a suitable medium-to-long term storage solution as well as a “fuel” for FCEV's because of its CO₂-free potential.     

Electrochemical characterization of single cell and short stack PEM electrolyzers based on a nanosized IrO2 anode electrocatalyst

A nanosized IrO₂ anode electrocatalyst was prepared by a sulfite-complex route for application in a proton exchange membrane (PEM) water electrolyzer. The physico-chemical properties of the IrO₂ catalyst were studied by termogravimetry–differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The electrochemical activity of this catalyst for oxygen evolution was investigated in a single cell PEM electrolyzer consisting of a Pt/C cathode and a Nafion^® membrane. A current density of 1.26 A cm⁻² was obtained at 1.8 V and a stable behavior during steady-state operation at 80 °C was recorded. The Tafel plots for the overall electrochemical process indicated a slope of about 80 mV dec⁻¹ in a temperature range from 25 °C to 80 °C. The kinetic and ohmic activation energies for the electrochemical process were 70.46 kJ mol⁻¹ and 13.45 kJ mol⁻¹, respectively. A short stack (3 cells of 100 cm² geometrical area) PEM electrolyzer was investigated by linear voltammetry, impedance spectroscopy and chrono-amperometric measurements. The amount of H₂ produced was 80 l h⁻¹ at 60 A under 330 W of applied electrical power. The stack electrical efficiency at 60 A and 75 °C was 70% and 81% with respect to the low and high heating value of hydrogen, respectively.     

Electronic nose application for determination of Penicillium digitatum in Valencia oranges

BACKGROUND: Penicillium digitatum and Penicillium italicum are responsible for one the most serious diseases occurring during storage of citrus fruits. Its early detection allows a relevant increase in shelf life, and in situ monitoring of fungal infections represents a very efficient tool to improve storage quality. In the case of metabolic alterations due to physiological or fungal pathologies, olfactometric analysis allows the detection of specific volatile biomarkers, thus providing an effective tool for postharvest quality control of fruits and vegetables. RESULTS: A total of 300 Valencia oranges were analysed with an electronic nose and results were screened by a multivariate classification technique, partial least squares discriminant analysis, in order to investigate whether the electronic nose could distinguish between Penicillium‐infected and non‐infected samples and to evaluate the efficiency of the group classifications. High percentages of correct classification were obtained at low levels of infection (100% for 2–5% infection in an independent test). CONCLUSION: The electronic nose may be successfully applied as a reliable, non‐destructive and non‐contact indirect technology for the identification of fungal strains in storage rooms, especially when the infection occurs in small percentages that are not easily identifiable by classic methodologies of inspection. Copyright © 2012 Society of Chemical Industry