Chronoamperometry as effective alternative technique for electro-synthesis of ortho-phenylendiamine permselective films for biosensor applications

Analyte quantification in first generation electrochemical biosensors is threatened by electro-active molecules, such as ascorbic acid (AA). Electrochemical deposition of ortho-phenylendiamine (oPD) on transducer considerably reduces AA interfering. These properties of poly-oPD (PPD) are influenced by electro-polymerization conditions. Chronoamperometry (CA) is proposed as an alternative technique for oPD electro-deposition over Pt. Pt/PPD sensors are evaluated through functional parameters related to AA rejection and analytical performances. N₂, O₂, and air bubbled supporting electrolyte and several step duration times are used. Best performing CA-PPD sensor is obtained in N₂-purged phosphate solution containing 300 mM oPD by means of a 1 s step duration/120 steps CA. High performing PPD is achieved in shorter time compared to commonly used constant potential amperometry. Aging of polymeric features and scanning electron microscopy investigations are performed and optimized CA electro-polymerization conditions are used to build up an efficient interference blocking layer in a glucose oxidase biosensor.     

Genomic and Epigenomic Profile of Uterine Smooth Muscle Tumors of Uncertain Malignant Potential (STUMPs) Revealed Similarities and Differences with Leiomyomas and Leiomyosarcomas

Uterine smooth muscle tumors of uncertain malignant potential (STUMPs) represent a heterogeneous group of tumors that cannot be histologically diagnosed as unequivocally benign or malignant. For this reason, many authors are working to obtain a better definition of diagnostic and prognostic criteria. In this work, we analyzed the genomic and epigenomic profile of uterine smooth muscle tumors (USMTs) in order to find similarities and differences between STUMPs, leiomyosarcomas (LMSs) and leiomyomas (LMs), and possibly identify prognostic factors in this group of tumors. Array-CGH data on 23 USMTs demonstrated the presence of a more similar genomic profile between STUMPs and LMSs. Some genes, such as PRKDC and PUM2, with a potential prognostic value, were never previously associated with STUMP. The methylation data appears to be very promising, especially with regards to the divergent profile found in the sample that relapsed, characterized by an overall CGI hypomethylation. Finally, the Gene Ontology analysis highlighted some cancer genes that could play a pivotal role in the unexpected aggressive behavior that can be found in some of these tumors. These genes could prove to be prognostic markers in the future.     

Aorta and skeletal muscle NO synthase expression in experimental heart failure

Nitric oxide (NO), the free radical that accounts for the biological activity of endothelium-derived relaxing factor, is synthesized from L-arginine by NO synthase (NOS). There is evidence that NO availability is reduced in the peripheral vasculature of patients with congestive heart failure (CHF). The aim of this study was to investigate the expression of NOS in the descending aorta and in the skeletal muscles of rats subjected to heart failure. The alkaloid, monocrotaline, was used to induce pulmonary hypertension and cardiac failure in rats. The expression of both the constitutive (ecNOS) and the inducible (iNOS) isoforms of the enzyme was assessed by Western blot analysis. In CHF animals, the ecNOS location in the aorta is altered: the endothelial protein expression is substantially reduced (from 0.083 +/- 0.012 to 0.003 +/- 0.004 OD/microgram total proteins, P < 0.001) whereas the expression of ecNOS in the smooth muscle is increased (from 0.024 +/- 0.004 to 0.059 +/- 0.009 OD/ microgram total proteins, P < 0.01). The total aortic ecNOS is diminished in CHF respect to control animals (0.062 +/- 0.009 v 0.107 +/- 0.013 OD/microgram total proteins, P < 0.01). On the contrary, no difference in ecNOS protein expression was observed in the extensor digitorum longus and soleus muscles. Furthermore, iNOS was not detected in any of the tissues considered. In conclusion, experimental CHF causes a re-setting of the ecNOS protein expression in the descending aorta but not in skeletal muscles. The reduced abundance of ecNOS in the aortic endothelium is consistent with the impairment of the vasodilating function reported in patients with CHF.     

Long-term treatment with cabergoline, a new long-lasting ergoline derivate, in idiopathic or tumorous hyperprolactinaemia and outcome of drug-induced pregnancy

Cabergoline (CAB), a new long-acting ergoline derivative, was shown to be very effective in reducing PRL levels in normal volunteers and in hyperprolactinemic patients. We evaluated the hormonal changes after discontinuation of long-term therapy with CAB as well as the safety of drug exposure during pregnancy both for mothers and babies. We therefore studied 48 patients (47 females and one male) with pathological hyperprolactinaemia (mean +/- SE, 117.2 +/- 15.2: median 73.2 micrograms/l), treated for 1-82 months (mean +/- SE, 28.3 +/- 3; median 18). After long-term treatment, CAB was withdrawn in 11 patients and PRL levels were persistently normal for almost 15 days and significantly lower (p < 0.05) than basal at 30, 45, 60, 90, 120 days. Three patients had normal PRL levels still at 45 days after treatment discontinuation. Nine patients became pregnant after 1-37 months (mean 12.4) of therapy. In two patients the pregnancy was interrupted spontaneously in one case and voluntarily in the other. In all but one patients after delivery or three-month breast feeding, PRL levels trended towards reduction. In two cases (one with microadenoma and one with idiopathic hyperprolactinaemia) PRL remained in the normal levels for 1-3 years after delivery. In conclusion CAB is able to inhibit plasma PRL levels for long time (up to 120 days) after withdrawal in patients with pathological hyperprolactinaemia treated with long-term therapy.     

Reliable and efficient forwarding in ad hoc networks

This paper focuses on packet forwarding in ad hoc networks and proposes a new approach to improve performance of nodes communication. In particular, we present a lightweight mechanism for REliable and Efficient Forwarding (REEF), which mitigates the effects of adverse situations caused by cooperation misbehavior or network fault conditions. It exploits nodes’ local knowledge to estimates route reliability, and multi-path routing to forward packets on the most reliable route. REEF becomes also a security mechanism in case of a security association established between the communication parties. This additional feature makes the mechanism robust, guaranteeing trustworthiness of the reliability estimator and security of data transmission.A new approach to cooperation enforcing is also proposed. The classical method denies service to misbehaving nodes by, for example, not serving their forwarding requests. We approach the problem less drastically, differentiating the quality of service provided to nodes according to their behavior. In other words, traffic of misbehaving nodes will flow through the network slower than that one of reliable nodes.     

Electrochemical synthesis and characterization of poly[3-(ω-bromoalkyl)thiophene]s

A novel series of functionalized polythiophenes incorporating 3-(ω-bromoalkyl) pendants are synthesized by electrochemical polymerization. The effect of the solvent on the electrosynthesis is investigated. The polymeric films are characterized using cyclic voltammetry, FT-IR, AFM and SEM microscopy. The poly[3-(6-bromohexyl)thiophene] film cast on GC or ITO electrode surface is compared with a sample obtained by a chemical method.     

About some corrosion mechanisms of AZ91D magnesium alloy

The present work is dedicated to a study of the corrosion resistance of AZ91D (91% Mg) alloy in wet environments. Three industrial alloys obtained by die-casting or sand casting were subjected to salt spray corrosion tests (ASTM-B117 standard) and immersion tests. Weight loss kinetic curves were measured. Surface analysis was performed by X-ray photoelectron diffraction (XPS). After corrosion the sand cast alloy presents a surface mainly enriched in hydroxides and carbonates while the die-cast alloy presents a surface enriched also in mixed Mg-Al oxides. The quantitative analysis of the rate Mg/Al shows an enrichment in aluminium for the die-cast alloys in comparison to the sand cast alloy.     

Homology modelling of the human eukaryotic initiation factor 5A (eIF-5A)

Homology modelling of the human eIF-5A protein has been performedby using a multiple predictions strategy. As the sequence identitybetween the target and the template proteins is nearly 30%,which is lower than the commonly used threshold to apply withconfidence the homology modelling method, we developed a specificpredictive scheme by combining different sequence analyses andpredictions, as well as model validation by comparison to structuralexperimental information. The target sequence has been usedto find homologues within sequence databases and a multiplealignment has been created. Secondary structure for each singleprotein has been predicted and compared on the basis of themultiple sequence alignment, in order to evaluate and adjustcarefully any gap. Therefore, comparative modelling has beenapplied to create the model of the protein on the basis of theoptimized sequence alignment. The quality of the model has beenchecked by computational methods and the structural featureshave been compared to experimental information, giving us agood validation of the reliability of the model and its correspondenceto the protein structure in solution. Last, the model was depositedin the Protein Data Bank to be accessible for studies on thestructure–function relationships of the human eIF-5A.