Adaptive memory programming for the vehicle routing problem with multiple trips

The Vehicle Routing Problem with Multiple Trips is an extension of the classical Vehicle Routing Problem in which each vehicle may perform several routes in the same planning period. In this paper, an adaptive memory algorithm to solve this problem is proposed. Computational experience is reported over a set of benchmark problem instances.     

mu-Conotoxin PIIIA, a new peptide for discriminating among tetrodotoxin-sensitive Na channel subtypes

We report the characterization of a new sodium channel blocker, mu-conotoxin PIIIA(mu-PIIIA). The peptide has been synthesized chemically and its disulfide bridging pattern determined. The structure of the new peptide is: [sequence: see text] where Z = pyroglutamate and O = 4-trans-hydroxyproline. We demonstrate that Arginine-14 (Arg14) is a key residue; substitution by alanine significantly decreases affinity and results in a toxin unable to block channel conductance completely. Thus, like all toxins that block at Site I, mu-PIIIA has a critical guanidinium group. This peptide is of exceptional interest because, unlike the previously characterized mu-conotoxin GIIIA (mu-GIIIA), it irreversibly blocks amphibian muscle Na channels, providing a useful tool for synaptic electrophysiology. Furthermore, the discovery of mu-PIIIA permits the resolution of tetrodotoxin-sensitive sodium channels into three categories: (1) sensitive to mu-PIIIA and mu-conotoxin GIIIA, (2) sensitive to mu-PIIIA but not to mu-GIIIA, and (3) resistant to mu-PIIIA and mu-GIIIA (examples in each category are skeletal muscle, rat brain Type II, and many mammalian CNS subtypes, respectively). Thus, mu-conotoxin PIIIA provides a key for further discriminating pharmacologically among different sodium channel subtypes.     

Composition and bioactive factor content of cowpea (Vigna unguiculata L. Walp) raw meal and protein concentrate

Analysis was done of the composition and bioactive factor content of whole meal, processed meal and protein concentrate from a cowpea cultivar (Vigna unguiculata L. Walp var. IT86D‐719) grown in Yucatan, Mexico and of changes in these parameters after soaking and dehulling. Both meals had a high protein content (247.53 and 257 g kg^?1 dry matter (DM) respectively). The protein concentrate was rich in protein (786 g kg^?1 DM) and lipids (58.47 g kg^?1 DM) and had an amino acid profile similar to that of the processed meal. The amino acid profiles of the meals almost covered human dietary requirements based on FAO/WHO/UNU‐suggested profiles but were deficient in sulphur amino acids. Trypsin inhibitor activity was high in both meals compared with levels found in previous studies. Trypsin inhibitor activity in the concentrate was not eliminated but was significantly reduced. Lectin activity, tannin levels, phytate levels and α‐amylase inhibitor activity were relatively low in the meals, and cyanogenic glucosides were not detected. Residual amounts of α‐amylase inhibitors, tannins and phytate were observed in the concentrate, and lectin activity was not detected. Results indicate that V. unguiculata L. Walp var. IT86D‐719 meals and protein concentrate are good potential foodstuffs in the Yucatan region. Copyright © 2006 Society of Chemical Industry     

Antioxidant activity of medicinal plant extracts in cookies

The antioxidant activity of ethanolic extracts of parsley, buckthorn, mint, caraway, and their mixture "Vitalplant" was evaluated, and the potential of "Vitalplant" mixture extract to retard the process of lipid oxidation in cookies was tested. The antioxidant activity was estimated by 2 direct (ESR) and 4 indirect (spectrophotometric) tests and correlated with the total phenolic and flavonoid content. The potential of "Vitalplant" mixture extract to retard the process of lipid oxidation in cookies was measured by thiobarbituric acid (TBA)-reactive-substances assay (TBARS) and DPPH˙ (1,1-diphenyl-2-picryl-hydrazyl) test. Significantly different (P < 0.05) amounts of total phenolics were found among extracts in the following order: mint > buckthorn > "Vitalplant" > parsley > caraway. Total flavonoid content varied from 0.510% (parsley) to 2.05% ("Vitalplant"). A statistically significant correlation was found between IC(50) values on DPPH˙ and total flavonoid content of the samples (r=- 0.94, P < 0.05) and between IC(50) values on DPPH˙ and IC(50) values on O(2) (·-) scavenging activity (r= 0.89, P < 0.05). A correlation between reducing activity and total phenolic content was found to be positive and statistically significant (r= 0.94, P < 0.05). "Vitalplant" mixture exhibited a relatively high antioxidant activity in most of the tests, which can be explained by synergistic effects of the ingredients of which it is composed. Finally, "Vitalplant" extract addition (2%, 4%, and 6%) improved antioxidant activity and oxidative stability of the cookies in dose-dependent manner. PRACTICAL APPLICATION: Supplementation of cookies with a mixture of Petroselini fructus, Frangulae cortex, Mentha piperitae folium, Carvi fructus can retard the process of lipid oxidation and elevate antioxidant activity of the final product.     

Thermal plasma spraying for SOFCs: Applications, potential advantages, and challenges

In this article, the applications, potential advantages, and challenges of thermal plasma spray (PS) processing for nanopowder production and cell fabrication of solid oxide fuel cells (SOFCs) are reviewed. PS processing creates sufficiently high temperatures to melt all materials fed into the plasma. The heated material can either be quenched into oxide powders or deposited as coatings. This technique has been applied to directly deposit functional layers as well as nanopowder for SOFCs application. In particularly, low melting point and highly active electrodes can be directly fabricated on zirconia-based electrolytes. This is a simple processing technique that does not require the use of organic solvents, offering the opportunity for flexible adjustment of process parameters, and significant time saving in production of the cell and cost reduction compared with tape casting, screen printing and sintering processing steps. Most importantly, PS processing shows strong potential to enable the deposition of metal-supported SOFCs through the integrated fabrication of membrane-electrode assemblies (MEA) on porous metallic substrates with consecutive deposition steps. On the other hand, the application of PS processing to produce SOFCs faces some challenges, such as insufficient porosity of the electrodes, the difficulty of obtaining a thin (<10 μm) and dense electrolyte layer. Fed with H₂ as the fuel gas and oxygen as the oxidant gas, the plasma sprayed cell reached high power densities of 770 mW cm⁻² at 900 °C and 430 mW cm⁻² at 800 °C at a cell voltage of 0.7 V.     

Sm0.5Sr0.5CoO3 + Sm0.2Ce0.8O1.9 composite cathode for cermet supported thin Sm0.2Ce0.8O1.9 electrolyte SOFC operating below 600 °C

The cathode is a key component in low temperature solid oxide fuel cells. In this study, composite cathode, 75 wt.% Sm_0.5Sr_0.5CoO₃ (SSC) + 25 wt.% Sm_0.2Ce_0.8O_1.9 (SDC), was applied on the cermet supported thin SDC electrolyte cell which was fabricated by tape casting, screen-printing, and co-firing. Single cells with the composite cathodes sintered at different temperatures were tested from 400 to 650 °C. The best cell performance, 0.75 W cm⁻² peak power operating at 600 °C, was obtained from the 1050 °C sintered cathode. The measured thin SDC electrolyte resistance R_s was 0.128 Ω cm² and total electrode polarization R_p(a + c) was only 0.102 Ω cm² at 600 °C.     

Use of ionic dialysance to calculate Kt/V in pediatric hemodialysis

Online clearance (OLC) monitor measures conductivity difference between dialysate entering and leaving the dialyser. Derived ionic dialysance (ID) represents effective urea clearance from which Kt/V is calculated, allowing Kt/V monitoring at every treatment without blood sampling. We tested ID accuracy in children and provide recommendations for its use. Using Fresenius machines 2008?K with built-in OLC monitors, we studied 45 hemodialysis (HD) sessions and 168 calculated Kt/V results in 11 patients. Urea distribution volume (V), needed to calculate Kt/V from ID, was estimated using three methods: Mellits and Cheek (MC), KDOQI recommended total body water nomograms (TBWN) and OLC-derived independent from tested HD sessions. Reference spKt/V from pre- and post-HD BUN (Daugirdas) was compared with Kt/V calculated from ID using three different estimated V's. ID was accurate in calculating Kt/V in children when V derived from OLC was used (P?=?0.42), with absolute error 0.14?±?0.12. If TBWN-derived V was used, Kt/V was consistently underestimated by 0.32?±?0.22. TBWN-derived V can still be recommended for use with OLC for monitoring trend in Kt/V, if underestimation of spKt/V of average 0.3 is accounted for. MC-derived V results in even greater underestimation of spKt/V and therefore cannot be recommended for use with OLC.     

Parallel conductance estimation by hypertonic dilution method withconductance catheter: effects of the bolus concentration and temperature

The conductance catheter has gained momentum since its introduction in cardiovascular dynamics back in 1980. However, measuring errors are still blurring its clinical acceptance. The main objective here was to study the effects of the injected saline concentration and temperature on the evaluation of the parallel conductance, Gp, and thus, on the correction volume Vp. That conductance, Gp, and its associated volume, Vp, were computed using 167 saline dilution curves obtained with boluses at different concentrations and temperatures, injected in seven anesthetized closed-chest dogs. The excursion of the total conductance relative to the steady-state value during a saline maneuver showed good correlation with the injected concentration at both studied temperatures. The reference parallel volume (one reference per dog) was defined as the average value obtained with three successive maneuvers, at 6-M concentration and at body temperature; therefore, the method acted as its own reference. The variation of Vp relative to the reference value was clearly dependent on the injected concentration and on its temperature; dispersion was greater at 22 degrees C than at 40 degrees C. The variability would recognize also other causes, such as uncertainty of the extrapolation procedure and the thoracic redistribution of electrical field lines. As conclusion, it is recommended to characterize each maneuver by its concentration and temperature. Body temperature and 6-M concentration appear as the most recommendable combination for the injectate in most animals. Finally, these results intend to characterize the Vp estimation procedure in order to minimize errors. The variability of Vp, in different experimental conditions, demonstrated that both concentration and temperature are additional parameters that may modify the Gp estimate.     

Molecular characterization of the phenylacetic acid catabolic pathway in Pseudomonas putida U: the phenylacetyl-CoA catabolon

Fourteen different genes included in a DNA fragment of 18 kb are involved in the aerobic degradation of phenylacetic acid by Pseudomonas putida U. This catabolic pathway appears to be organized in three contiguous operons that contain the following functional units: (i) a transport system, (ii) a phenylacetic acid activating enzyme, (iii) a ring-hydroxylation complex, (iv) a ring-opening protein, (v) a beta-oxidation-like system, and (vi) two regulatory genes. This pathway constitutes the common part (core) of a complex functional unit (catabolon) integrated by several routes that catalyze the transformation of structurally related molecules into a common intermediate (phenylacetyl-CoA).     

Ultrasonic spray pyrolysis of surface modified TiO2 nanoparticles with dopamine

Spherical, submicronic TiO₂ powder particles were prepared in the low temperature process of ultrasonic spray pyrolysis (150 °C) by using as a precursor aqueous colloidal solutions consisting of surface modified 45 Å TiO₂ nanoparticles with dopamine. Detailed structural and morphological characterization of colored submicronic TiO₂ spheres was performed by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser particle size analysis and FTIR techniques. Also, optical characterization of both dopamine-modified TiO₂ precursor nanoparticles and submicronic TiO₂ powder particles was performed using absorption and diffuse reflectance spectroscopy, respectively. A significant decrease of the effective band gap (1.9 eV) in dopamine-modified TiO₂ nanoparticles compared to the band gap of bulk material (3.2 eV) was preserved after formation of submicronic TiO₂ powder particles in the process of ultrasonic spray pyrolysis under mild experimental conditions. Due to the nanostructured nature, surface-modified assemblage of TiO₂ nanoparticles preserved unique ability to absorb light through charge transfer complex by photoexcitation of the ligand-to-TiO₂ band, conventionally associated with extremely small TiO₂ nanoparticles (d < 20 nm) whose surface Ti atoms, owing to the large curvature, have penta-coordinate geometry.