Stimuli responsive gels based on interpenetrating network of hydroxy propylcellulose and poly(N-isopropylacrylamide)

Sequential networks made of hydroxypropylcellulose (HPC) and poly(N-isopropylacrylamide) (PNIPA) were synthesized by adsorption of a solution of NIPA monomer into a dried porous HPC network. NIPA polymerization inside the network allows us to obtain IPN which show, as the neat components, thermosensitive volumetric behavior. The volumetric transition temperatures range between those of HPC and PNIPA gels. Moreover, as the rate of the swelling-deswelling process is quite higher than that of PNIPA irrespective of the composition, the synthesis method appears interesting in modulated thermosensitive behavior and in the application of this kind of IPN.     

Specificity of substrate recognition by Pseudomonas fluorescens N3 dioxygenase. The role of the oxidation potential and molecular geometry

Pseudomonas fluorescens N3 is able to grow on naphthalene as the sole carbon and energy source. The mutant TTC1, blocked at the dihydrodiol dehydrogenase level, which can transform the hydrocarbon into the corresponding dihydrodiol, has been used to produce bioconversion products. To rationalize the different grades of conversion obtained with different substrates, a study was performed using non-naphthalene derivatives, including benzenes, conjugated benzenes, and polycyclic aromatic hydrocarbons. The corresponding diols obtained by bioconversion have been isolated and characterized. A theoretical model that considers both energy and geometry factors has been proposed to rationalize the experimental data. Good agreement has been found between the calculated values and the experimental results.     

Helicobacter pylori eradication in the healing and recurrence of benign gastric ulcer: a two-year, double-blind, placebo controlled study

STUDY OBJECTIVE: To evaluate the safety and efficacy of monitored anesthesia care (MAC) in patients who undergo a novel treatment for hepatocellular cancer in which procedure-related hemodynamic instability is problematic. DESIGN: Nonrandomized open study. SETTING: University cancer center operating room. PATIENTS: Nine patients scheduled for hepatic arterial infusion of doxorubicin with complete hepatic venous isolation and extracorporeal chemofiltration (no more than 3 procedures per patient). INTERVENTIONS: Hepatic venous isolation was achieved with a dual-balloon inferior vena cava catheter connected to an extracorporeal circuit containing chemofilters. Doxorubicin was infused through the hepatic artery and filtered from the venous blood, which was returned to the patient through an internal jugular venous catheter. Each patient received a bolus of propofol (200 micrograms/kg) and one of alfentanil (2 micrograms/kg) followed by simultaneous infusions of propofol and alfentanil for percutaneous placement of the catheters and operation of the extracorporeal circuit. Drug rates were varied to maintain a sedative-analgesic state of calm, comfort, minimal movement, and adequate respiratory function. Prior to circuit initiation, patients were preloaded with crystalloid. During circuit operation, hypotension was treated with intravenous (IV) phenylephrine and crystalloid. MEASUREMENTS AND MAIN RESULTS: End-tidal CO2 (PETCO2), respiratory rate, oxygen saturation (SaO2), arterial blood pressure (BP), and heart rate (HR) were monitored. Systolic, diastolic, and mean arterial pressure (MAP), and HR were compared before, during, and after hepatic venous isolation and chemofiltration. Doses and infusion rates of propofol, alfentanil, and phenylephrine were recorded for each treatment. Hypotension occurred in 11 of 13 procedures when blood was directed through the chemofilters and was successfully treated with phenylephrine (dose range 40 to 5,733 micrograms) and crystalloid. Blood pressure returned to the baseline value on termination of the circuit. Throughout the sedation, patients were easily arousable, analgesia was adequate, and PETCO2 level of 38 +/- 4 mmHg and SaO2 greater than 94% were maintained. Mean doses and infusion rates of MAC drugs were, respectively: propofol, 261 +/- 88 mg and 23.7 +/- 3.6 micrograms/kg/min; alfentanil, 3,350 +/- 1,468 micrograms and 0.32 +/- 0.14 microgram/kg/min. CONCLUSIONS: Patients undergoing this novel cancer treatment are safely and effectively managed by MAC achieved with simultaneous infusions of alfentanil and propofol. Procedure-associated hypotension is easily treated with IV phenylephrine and crystalloid.     

Dynamic time warping in the analysis of event-related potentials.

The aim of this article is to compute reliable templates of event-related potentials (ERPs) for homogeneous groups of subjects and to automatically quantify the morphological characteristics of the ERPs. We developed a method based on dynamic time warping (DTW). The method was applied to ERPs recorded from normal and dyslexic children during two reading tasks. We found that characteristic latency and amplitude changes of ERP components are due to task and pathology. Our results support the idea that dyslexia involves different and complex cerebral functions aside from the language system. This mathematical approach provides reproducible analysis criteria that are crucial for the reliability of ERP analysis.     

Hot-carrier reliability of 20V MOS transistors in 0.13 μm CMOS technology

This paper presents results of reliability investigation of 20 V N-Drift MOS transistor in 0.13 μm CMOS technology. Due to high performances required for CMOS applications, adding high voltage devices becomes a big challenge to guarantee the reliability criteria. In this context, new reliability approaches are needed. Safe Operating Area are defined for switch, V_ds limited and V_gs limited applications in order to improve circuit designs. For V_ds limited applications, deep doping dose effects in drift area are investigated in correlation to lifetime evaluations based on device parameter shifts under hot carrier stressing. To further determine the amount and locations of hot carriers injections, accurate 2D technological and electrical simulations are performed and permit to select the best compromise between performance and reliability for N-Drift MOS transistor.     

An agent‐based approach for managing e‐commerce activities

In this article, we propose an agent‐based approach for managing e‐commerce activities. In our approach, an agent is present in each e‐commerce site, managing the information stored there. In addition, another agent is associated with each customer, handling his/her profile. The proposed approach is based on the use of a particular conceptual model called the Behaviour‐Semantic Distance and Relevance (B‐SDR) network, which is capable of uniformly representing and handling information stored in e‐commerce sites and customer profiles. The capabilities of the B‐SDR network model are exploited to let customer and site agents cooperate in such a way in order to support a customer in identifying, whenever he/she accesses an e‐commerce site, those products and services present in the site itself and for better matching his/her interests. The approach has been implemented in a prototype in which its functionalities are discussed here also. © 2004 Wiley Periodicals, Inc.     

Polymorphism in Sr3Fe2O7−x

The compound Sr₃Fe₂O_7–x , with variable iron valence, was investigated by X-ray powder techniques, both at room and at high temperatures. If the material is examined in massive form, a single phase called -Sr₃Fe₂O_7–x appears as previously reported in the literature. This -phase is tetragonal and exhibits the lattice parameters: a=3.874 and c=40.314 Å. Two other phases, called and -Sr₃Fe₂O_7–x , respectively, can be obtained on heating the finely powdered material when laid on a flat platinum support. The form is stable up to 1275° C, while the form is revealed only above 1275° C and changes always into -Sr₃Fe₂O_7–x when quenched. Both and phases are tetragonal, with a=4.001 and c= 58.251 for the form and a=4.013, c=57.092 Å for the form. The transition involves a true phase equilibrium, while the transformation is possible only by means of a suitable mechanical treatment of the material.     

Model dependency of multivariate autoregressive spectral analysis

A combination of simulations and experimental data analysis has been used to demonstrate that, because cardiovascular control represents a complex linking of input and output parameters, interpreting the variability of individual parameters such as heart rate and arterial pressure virtually requires the use of techniques that quantify control by relating these inputs and outputs. Transfer functions represent appropriate techniques for this purpose. Further, despite the complexities of in vivo physiological control, many of the control elements can be well characterized by only taking into account single inputs and outputs and using a bivariate AR model. However, occasionally when two control systems have a strong and simultaneous influence on a single output parameter, such as arterial pressure and respiratory activity on RR interval, an expansion of the model to the general multivariate case may be required for a complete interpretation. Finally, although not fully demonstrated here, because of the closed-loop nature of cardiovascular control it is likely that algorithms that include causality to account for this characteristic, such as the AR formulation, will most accurately identify the transfer relations     

Design considerations for fractional-slot winding configurations of synchronous machines

This paper presents some design considerations for synchronous machines characterized by a fractional number of slots per pole per phase. The main advantage of this configuration is a smooth torque, which is due to the elimination of periodicity between slots and poles. A second advantage is a higher fault-tolerant capability, making the machine able to work even in faulty conditions. However, the fractional-slot configuration presents a high content of MMF harmonics that may cause an unbalanced saturation and thus an unbearable torque ripple. A method to design fractional-slot machines is illustrated in this paper, including double-layer and single-layer windings. The analytical computation is extended to determine the harmonics of MMF distribution. Their effect is highlighted in isotropic as well as anisotropic machines. Finally, some considerations are reported to avoid unsuitable configurations.