Co-nonsolvency of PMMA

Summary Phase separation temperatures have been determined in the system PMMA/chlorobutane + amyl acetate. This liquid mixture is a co-nonsolvent (co-precipitant) of the polymer. The molecular origin of such co-nonsolvency is discussed in terms of the interactions pressumably present in the system.     

A SAX-GA approach to evolve investment strategies on financial markets based on pattern discovery techniques

This paper presents a new computational finance approach, combining a Symbolic Aggregate approXimation (SAX) technique together with an optimization kernel based on genetic algorithms (GA). The SAX representation is used to describe the financial time series, so that, relevant patterns can be efficiently identified. The evolutionary optimization kernel is here used to identify the most relevant patterns and generate investment rules. The proposed approach was tested using real data from S&P500. The achieved results show that the proposed approach outperforms both B&H and other state-of-the-art solutions.     

Electromigration-aware analog Router with multilayer multiport terminal structures

The combined effects of current densities and temperature in the interconnects may cause the failure of a circuit due to electromigration (EM). EM becomes increasingly more relevant with the ongoing reduction in circuit sizes caused by the evolution of nanoscale integration processes. Therefore EM effects must be taken into account in the design of both power networks and signal wires of analog or mixed-signal integrated circuits (ICs), to make their impact on the circuits’ reliability negligible. In previous EM-aware analog IC routing approaches, ‘dot-models’ are assumed for the terminals, i.e. each terminal has only one port that needs to be routed; however, in practice, analog standard cells usually contain multiple electrically-equivalent locations, often distributed over different fabrications layers, where legal connections can be made, multiport terminals, which need to be properly explored. This paper describes an EM-aware routing methodology considering multiport multiterminal signal nets of analog ICs. The complete design flow is detailed and demonstrated with experimental results and also, by generating the routing for two typical analog circuit structures for the UMC 130 nm design process; the automatically generated layouts are validated using the industrial grade Calibre^® tool.     

A proposal for ground measurement techniques in substations fedexclusively by power cables

It was previously reported that when a fault to ground occurs in a substation fed exclusively by power cables, around 98% of the fault current can flow along the cable sheaths and auxiliary underground conductors, producing no local potential rise. This can modify greatly the results of ground measurements carried out in this type of substation, unless special care is taken and correction factors are suitably applied. The authors extend the experience gained during those measurement and determine a set of procedures that allow ground measurements to be made in substations fed solely by power cables. They set forth basic requirements for the measuring circuits and for handling the measured data. They then discuss power cable sheath characteristics in some step-down urban substations and ground measurement strategy for such substations     

Automatic topology selection and sizing of class-D loop-filters for minimizing distortion based on an evolutionary optimization kernel

This paper presents an optimization methodology for continuous time loop-filters design applied to Class-D amplifiers. The methodology is based on an evolutionary optimization approach which integrates both the topology selection and circuit sizing by automatically generating optimal sized topologies and performance tradeoffs for the Class-D amplifier. The presented approach is demonstrated on two cases: for the design of a half-bridge amplifier and for a fully differential BTL class-D loop filter topology that achieves less than 0.003% THD at 680?mW output power in typical 0.18???m CMOS technology.     

Cytolytic activity in the genus Leishmania: involvement of a putative pore-forming protein

We describe here that parasites of the genus Leishmania contain a cytolytic activity which acts optimally at pH 5.0 to 5.5 and at 37 degrees C in vitro. or the four species examined, Leishmania (Leishmania) amazonensis and Leishmania (Leishmania) major presented considerable hemolytic activity, whereas Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis showed little and no hemolytic activity, respectively. The cytolytic factor of L. amazonensis promastigotes was characterized as a protein with no protease-, phospholipase-, or detergent-like activity, probably localized inside membranous vesicles. The use of osmotic protectants revealed the colloid-osmotic nature of hemolysis, which is indicative of pore formation in the membranes of target cells. This putative pore-forming protein also damaged nucleated cells, including macrophages, causing an increase in their membrane permeability with leakage of cytoplasmic proteins. Both promastigotes and amastigotes express this lytic activity, suggesting that the cytolysin may have a function in both stages of this parasite. The pH and temperature required for optimal activity indicate that it might be more effective within the mammalian host, particularly inside the macrophage parasitophorous vacuole. In promastigotes of L. amazonensis, the expression of lytic activity seems to be regulated during their growth in vitro, being maximal at the early stationary phase.     

The effect of side chains on the partial specific volumes of poly(o-alkylphenyl methacrylate)s and polydiitaconates

Partial specific volumes ν of a series of poly(o-alkyl phenyl methacrylate)s and polydiitaconates were determined by density measurements, in toluene and tetrahydrofuran solutions, respectively. The effect of the size and nature of the side groups on partial specific volume is analyzed. Good agreement is found between the experimental ν values and those obtained theoretically from the group contribution method.     

Bioactivity-based screening methods for antibiotics residues: a comparative study of commercial and in-house developed kits

Two bioactivity-based screening methods for antibiotic residue analysis (FAST Antimicrobial Screening Test and PremiTest) were compared, in terms of sensitivity, with a new in-house developed tube test assay using Escherichia coli. Tests were performed using antibiotic standards, spiked samples and real incurred samples. The minimum inhibitory concentration (MIC) for several antibiotics was established and compared with maximum residue levels (MRLs) in samples. The results of all evaluated tests are compared with liquid chromatography-tandem mass spectrometry multi-residue screening tests to compare parameters such as sample preparation, cost, time of analysis and confidence in results. For all tests, values of half the maximum residue limit (0.5 × MRL) were considered as a satisfactory target for a screening method. The potential and limitations of each method are discussed to indicate more rational and effective strategies for high-throughput residue monitoring and surveillance programmes. It was concluded that bioactivity-based screening methods are a useful tool, but the best compromise between minimum performance limits, cost and selectivity must be taken into account. For laboratories equipped with mass spectrometry, multi-class screening methods provide more specific responses with high sensitivity.