Expression of FcRII in chronic lymphocytic leukemia B cells. Gamberale, Romina; Geffner, Jorge Raúl; Sanjurjo, Julieta; Fernandez Calloti, Paula X.; Arrosagaray, Guillermo; Sánchez Ávalos, Julio César Américo; Giordano, Mirta Nilda We have read with interest the paper from Damle et al analyzing the surface membrane phenotype of B lymphocytes in chronic lymphocytic leukemia (B-CLL). The authors stated that the leukemic cells from all B-CLL patients evaluated (irrespective of immunoglobulin heavy chain (IgVH) gene mutational status) bear the phenotype of antigen-experienced B cells based, among other features, on the very low expression of Fcγ receptors type IIb (FcγRIIb, CD32), which is the main isoform of FcγRII in B lymphocytes.

Interaction between process design and process operability of chemical processes: An eigenvalue optimization approach Blanco, Anibal Manuel; Bandoni, Jose Alberto An increasing effort is being devoted to consider controllability issues (or in a wider sense operability issues) at the process design stage. Controllability has mainly to do with dynamics in the face of disturbances. One philosophy for the integration of design and controllability is to explicitly consider dynamic elements within the process design formulation. An outstanding feature of dynamics is stability, which is related with the spectrum (set of eigenvalues) of the dynamic system Jacobian matrix. Dynamic convergence speed may also be analyzed in terms of the eigenvalues of the matrix from a Lyapunov function related to the Jacobian of the system. It is the purpose of this contribution to formulate and solve the chemical process design problem, considering process dynamics from an eigenvalue optimization approach.

Retrofit of multiproduct batch plants through generalized disjunctive programming Montagna, Jorge Marcelo; Vecchietti, Aldo The retrofit problem for multiproduct batch plants deals with the modification of the original structure of the plant to meet new production conditions such as the introduction of new products, a new supply pattern, etc. For this problem, a disjunctive model is presented, which takes into consideration every usual alternative about the configuration of units and storage tanks. A disjunction is generated for that purpose. The selection of one of those alternatives sets up all the corresponding constraints, which are: operation time, unit size and cost, etc. Finally, the performance of this approach is analyzed through the resolution of a set of examples.

Centothecoid grasses and the evolution of panicoid spikelets Rua, Gabriel Hugo An evolutionary pathway leading to acrotonous, 2-flowered spikelets of Panicoideae has been suggested elsewhere, which involves apical reduction of many-flowered mesotonic spikelets. Current phylogenies of the grass family show a sister relationship between Panicoideae and Centothecoideae. A survey of spikelet structures occurring among centothecoid grasses shows that some representatives of this group have intermediate morphologies which are consistent with that hypothesis. Chasmanthium and Bromuniola have many-flowered spikelets with a barren proximal floret, whereas Thysanolaena, Gouldochloa and Gynerium represent a series of apical reductions leading to 2-flowered spikelets. Moreover, many-flowered spikelets with 1-3 proximal male flowers followed by several female-fertile ones occur in Puelioideae, one of the early-diverging clades of the Poaceae. This fact suggests that some "panicoid" characters may have evolved long before the radiation of the Panicoideae took place.

Predictive functional control based on fuzzy model: magnetic suspension system case study Lepetic, Marko; Skrjanc, Igor; Chiacchiarini, Hector Gerardo; Matko, Drago Fuzzy model based predictive functional controller (FPFC) is applied to the magnetic suspension system - a pilot plant for magnetic bearing. High quality control requirements are short settle time with a-periodical step response and zero steady-state error. Open loop unstable process was stabilised with linear lead compensator. The FPFC was used as a cascade controller. Due to some model uncertainties, the Takagi-Sugeno fuzzy model of stabilised system was obtained using fuzzy identification. Comparing to PID, it improved quality and robustness performance. With its computational efficiency, it proved to be ideal solution for high sampling frequency.

Lattice gas study of the kinetics of the NO-CO catalytic reaction on Pd nanoclusters Bustos Giunta, Victor Angel; Uñac, Rodolfo Omar; Zgrablich, Giorgio; Henry, Claude R. The kinetics of the NO-CO reaction on Pd nanoclusters is studied through a lattice-gas model and Monte Carlo simulation. Pd nanoclusters with three typical sizes: 2.8 nm, 6.9 nm and 15.6 nm, are considered. These nanoclusters have been epitaxially grown on MgO(100) and tested for the NO-CO reaction in previous experimental work [ref. 9-11: C. H. F. Peden, D. W. Goodman, D. S. Blair, P. J. Berlowitz, G. B. Fisher and S. H. Oh, J. Phys. Chem., 1988, 92, 1563; C. Duriez, C. R. Henry and C. Chapon, Surf. Sci., 1991, 253, 190; L. Piccolo and C. R. Henry, Appl. Surf. Sci., 2000, 162-163, 670], thus providing the motivation for the present study. According to their size, the nanoclusters present different proportions of Pd(100) and Pd(111) facets. The effects of CO and NO desorption are found to be of fundamental importance for the behavior of the system. In all cases the medium size particles are found to be the most active. At low temperature, where NO desorption can be neglected (since the activation energy for desorption of NO on Pd is about 5 kcal mol-1 greater than that for the desorption of CO), the largest particles are revealed as the less active, while at high temperature, where both NO and CO desorption take place, the smallest particles are found to be the less active. These results are in concordance with the experimentally observed behavior.

Diffusion of particles adsorbed on a triangular lattice: Pairwise and three-particle interactions Tarasenko, Alexander A.; Nieto Quintas, Felix Daniel; Jastrabík, Lubomír; Uebing, Christian In the present paper, the influence of both pairwise and three-particle interactions on the mobility of adsorbed particles diffusing on a lattice with triangular symmetry has been studied. Two different techniques has been used for describing the surface diffusion phenomenon. On one hand, explicit expressions for the chemical and jump diffusion coefficients have been calculated by using real-space renormalization group (RSRG) approach. A number of the RSRG transformations with blocks of different sizes and symmetries have been investigated. In particular, it has been shown that the precision of the method depends strongly not only on the number of sites in the RSRG blocks but also on their composition and structure. On the other hand, numerical simulations by using the Monte Carlo scheme has been used to simulate the process of particle migration. Using both methods, adsorption isotherms for different temperatures and the coverage dependencies for the thermodynamic factor and the chemical diffusion coefficient have been calculated. The behavior of the above mentioned quantities has been compared when the adparticles interact via only either pairwise or three-particle interactions. Despite the fact that both methods constitute very different approaches, the correspondence of numerical data with analytical results is surprisingly good. Therefore, it can be concluded that the RSRG method can be successfully applied for lattice gas systems to characterize the thermodynamic and kinetic properties of strongly interacting adsorbates.

Objective method for classifying air masses: an application to the analysis of the Buenos Aires' (Argentina) urban heat island intensity Bejarán, Rubén Aníbal; Camilloni, Ines Angela During recent years, numerous studies have examined the Buenos Aires urban climate, but the relationship between large-scale weather conditions and the Buenos Aires urban heat island (UHI) intensity has not been studied. The goal of this paper is to apply an objective synoptic climatological method to identify homogeneous air masses or weather types affecting Buenos Aires during winter, and to relate the results to the UHI intensity. A K-means clustering method was used to define six different air masses considering the 03:00, 09:00, 15:00 and 21:00 LT surface observations of dry bulb temperature, dew point, cloud cover, atmospheric pressure and wind direction and velocity at Ezeiza, the most rural meteorological station of the Buenos Aires metropolitan area (Fig. 1). Results show that the mean UHI intensity is at its maximum (2.8 °C) a few hours before sunrise when conditions are dominated by cold air masses associated with cold-core anticyclones, weak winds and low cloud cover. Inverse heat islands are found during the afternoon for all air masses indicating that surface processes are not dominant at that time. The relatively infrequent and warmest air mass is the only one that presents a mean negative urban-rural temperature difference (−0.1 °C) during the afternoon with the smallest diurnal cycle of the UHI intensity probably due to the prevailing high humidity and cloudy sky conditions. The paper provides an insight into the Buenos Aires urban?rural temperature difference under a variety of winter weather types and results could be useful to improve local daily temperature forecasts for the metropolitan area of Buenos Aires on the basis of the routine forecasts of weather types.

Modelling corn starch swelling in batch systems: effect of sucrose and hydrocolloids Krüger, Alejandra; Ferrero, Cristina; Zaritzky, Noemi Elisabet Hydrocolloids are used in starch-based products to improve stability and to obtain specific textural characteristics. In stirred batch systems with constant jacket temperature, xanthan gum, guar gum and sodium alginate (1% w/w) were added to corn starch (10% w/w) and sucrose (15% w/w) in aqueous systems to test their effects on granule swelling, starch gelatinization temperatures and viscoelastic behavior of the hot paste. As heating is not instantaneous, time–temperature relationships cannot be avoided. In this regard, heat penetration was faster in viscoelastic systems with lower complex dynamic modulus ðGÞ values, while pastes containing gums showed lower heat transfer rates during gelatinization. Microscopy and image analysis were applied to describe the granule swelling process in starch gelatinization. Starch granule swelling was considerably reduced by the presence of gums due to the lower heating rates and the decreased mobility of water molecules. The presence of sucrose increased starch gelatinization temperatures, measured by differential scanning calorimetry; gum addition did not show a significant influence on these temperatures. The effect of time and temperature on the starch swelling process was modelled considering, as driving force, the difference between the instantaneous mean curvature of the granule (reciprocal of the diameter) and the asymptotic curvature. Gelatinization rate constants were calculated for the different pastes and the lowest values were observed for starch pastes added with gums. Activation energies ranged from 80 ( 14) to 119 ( 3) kJ mol 1, being comparable to values reported in the literature for starch gelatinization measured by different methods.

Infinite dilution activity coefficients of solvents in fatty oil derivatives Ferreira, O.; Foco, Gloria Margarita Inverse gas-liquid chromatography has been applied to measure infinite dilution activity coefficients (γ ∞) of different solutes in low and high molecular weight triacylglycerides (TAGs) and in mixtures of carboxylic acids with TAGs. The γ ∞ data obtained were used to determine binary interaction and size related parameters for the GCA-EOS group contribution with association equation of sate.

Optimization of the operating conditions of azeotropic distillation columns with pervaporation membranes Hoch, Patricia Monica; Daviou, Maria Carolina; Eliceche, Ana Maria The main objective of this work is the optimization of the operating conditions of azeotropic distillation columns in hybrid distillation/pervaporation systems. In the configuration analyzed, a liquid side stream extracted from the azeotropic distillation column with the distributing non-key component is treated in a pervaporation membrane while the retentate is recycled to the column. The pervaporation membrane separates the pure distributing non-key component from the mixture, thus helping to improve the purity in the top and/or bottom products of the distillation column. The case study shows the hybrid process of a distillation column combined with pervaporation membranes, compared to the classical two-column process for Methyl tert-Butyl Ether production. In both cases, the operating conditions of the distillation columns such as reflux ratio, product and side draw flowrates are selected optimally. The numerical results show a significant reduction in operating cost obtained by using a pervaporation membrane instead of the second column in the original process.

Restricted weak type inequalities for convolution maximal operators in weighted Lp spaces Bernardis, Ana Lucia; Martín Reyes, Francisco Javier Let φ: ℝ → [0, ∞) be an integrable function such that φ(-∞,0) = 0 and φ is decreasing in (0, ∞). Let τh f (x) = f (x - h), with h ∈ ℝ/{0} and φ R(x) = (1/R)φ(x/R), with R > 0. In this paper we study the pair of weights (u, v) such that the operators Mτhφ f (x) = supR>0 |f| * [tau;hφ]R (x) are of restricted weak type (p, p) with respect to (u, v), 1 ≤ p < ∞. As particular cases, these operators include some maximal operators related to Cesàro convergence. We characterize those functions φ for which Mτhφ is of (restricted) weak type (p, p) with respect to the Lebesgue measure. Unlike the case of the Cesàro maximal operators, it follows from the characterization that the interval of those p such that M τhφ is of weak type (p, p) can be left-closed, [p 0, ∞], or left-open, (p0, ∞], without having restricted weak type (p0, p0).

New evolutionary models for massive ZZ Ceti stars, I : first results for their pulsational properties Althaus, Leandro Gabriel; Serenelli, A. M.; Corsico, Alejandro Hugo; Montgomery, M. H. Chaotic orbits suffer significant changes as a result of small perturbations. One can thus wonder whether the dynamical friction suffered by a satellite on a regular orbit, and interacting with the stars of a galaxy, will be different if the bulk of the stars of the galaxy are in regular or chaotic orbits. In order to check that idea, we investigated the orbital decay (caused by dynamical friction) of a rigid satellite moving within a larger stellar system (a galaxy) whose potential is nonintegrable. We performed numerical experiments using two kinds of triaxial galaxy models: (1) the triaxial generalization of Dehnen's spherical mass model (Dehnen; Merritt & Fridman); (2) a modified Satoh model (Satoh; Carpintero, Muzzio, & Wachlin). The percentages of chaotic orbits present in these models were increased by perturbing them. In the first case, a central compact object (black hole) was introduced; in the second case, the perturbation was produced by allowing the galaxy to move on a circular orbit in a logarithmic potential. The equations of motion were integrated with a non-self-consistent code. Our results show that the presence of chaotic orbits does not affect significantly the orbital decay of the satellite.

Up-regulated expression of MICA on activated T lymphocytes involves Lck and Fyn kinases, and signaling through MEK1/ERK, p38 MAP kinase and calcineurin Molinero, Luciana Lorena; Fuertes, Mercedes Beatriz; Fainboim, Leonardo; Rabinovich, Gabriel Adrián; Zwirner, Norberto Walter Major histocompatibility complex class I-related chain (MICA) is a cell stress-regulated molecule recognized by cytotoxic cells expressing the NKG2D molecule. MICA can be induced on T cells after CD3 or CD28 engagement. Here, we investigated the intracellular pathways leading to activation-induced expression of MICA. The Src kinase inhibitor PP1 inhibited up-regulated expression of MICA on anti-CD3-stimulated T cells. Downstream signaling routes involved mitogen-activated protein kinase (MAPK) kinase (MEK)1/extracellular signal-regulated kinase (ERK), p38 MAPK, and calcineurin, as MICA expression was prevented by U0126, SB202190, cyclosporin A, and FK506. Also, Lck and Fyn as well as MEK1/ERK and p38 MAPK were found to regulate MICA expression in anti-CD28/phorbol 12-myristate 13-acetate-stimulated T cells. Expression of MICA on activated T cells involved interleukin-2-dependent signaling routes triggered by Janus tyrosine kinases/signal transducer and activators of transcription and p70S6 kinase, as it could be inhibited by AG490 and rapamycin. This is the first demonstration of the intracellular pathways involved in activation-induced expression of MICA, which may reveal potential targets for immune intervention to modulate MICA expression in pathological disorders.

Role of prolactin in the regulation of cytosolic NADP isocitrate dehydrogenase in the liver of the male rat Zirulnik, Fanny; Anzulovich Miranda, Ana Cecilia; Larregle, Ethel Viviana; Jahn, Graciela Alma; Gimenez, Maria Sofia The activity of cytosolic NADP-linked isocitrate dehydrogenase (ICDH) in rat liver was determined. The administration of 2-bromo-α-ergocryptine (CB-154) to male rats produced a significant increase of the enzyme activity and a decrease of serum prolactin (PRL) levels in relation to control animals. Male rats 21 days after castration had lower levels of serum prolactin and higher activity of the enzyme than controls. Injection of PRL to castrated male rats lowered the enzymatic activity to control values. In intact rats injected with prolactin, the activity of the enzyme also decreased. Female rats were separated into the following groups: (a) virgins; (b) rats on day 15 of lactation; (c) ovariectomized rats. The enzymatic activity was similar in the different groups, but significantly higher than in male rats. However, serum PRL was significantly increased in 15 days lactating rats and decreased in ovariectomized ones in relation to virgins. We conclude that PRL regulates hepatic ICDH activity in male, but not in female rats. Incubation of isolated hepatocytes from intact or castrated male rats maintained the difference in ICDH activity observed in vivo, while there were no differences in ICDH activity in non-parenchymal cells. Addition of PRL, CB-154, androgens or antiandrogens to isolated hepatocytes from intact and castrated rat, had no effect on the ICDH activity, suggesting that the effect of PRL is exerted at the transcriptional level.

Extraction of molybdenum by a supported liquid membrane method Basualto, Carlos; Marchese, Jose; Valenzuela, Fernando R.; Acosta, Adolfo Francisco This is a report on the extraction of molybdenum(VI) ions using a supported liquid membrane, prepared by dissolving in kerosene, the extractant Alamine 336 (a long-chain tertiary amine) employed as mobile carrier. A flat hydrophobic microporous membrane was utilised as solid support. Appropriate conditions for Mo(VI) extraction through the liquid membrane were obtained from the results of liquid-liquid extraction and stripping partition experiments. The influence of feed solution acidity, the carrier extractant concentration in the organic liquid film and the content of strip agent on the metal flux through membrane were investigated. It was established that maximal extraction of metal is achieved at a pH 2.0 if sulphuric acid is used in the feed solution and at a pH value over 11.0 if Na2CO3 is used as strip agent. Moreover, the molybdenum extraction through membrane is enhanced when a 0.02 mol 1-1 content of the amine carrier in the organic phase is used. The present paper deals with an equilibrium investigation of the extraction of Mo(VI) by Alamine 336 and its permeation conditions through the liquid membrane, and examines a possible mechanism of extraction.

Weather regimes in the South American sector and neighbouring oceans during winter Solman, Silvina Alicia; Menendez, Claudio Guillermo We classified 34 years of winter daily 500 hPa geopotential height patterns over the eastern South Pacific-South America-South Atlantic region using the K-means clustering method. We found a significant classification into five weather regimes (WRs) defined as the most frequent large-scale circulation anomalies: WR1 (trough centred downstream of the Drake Passage), WR2 (trough over the SW Pacific and ridge downstream), WR3 (ridge over the SE Pacific and NW–SE trough downstream), WR4 (trough over the SE Pacific and NW–SE ridge downstream) and WR5 (weak ridge to the west of southern South America). We also analysed their persistence and temporal evolution, including transitions between them and development around onsets and breaks of each regime. The preferred transitions, WR1→WR3→WR2→WR4→WR1 and also WR1→WR3→WR2→WR1, suggest the progression of a Rossby wave-like pattern in which each of the regimes resemble the Pacific-South America modes. Significant influence of the WRs on local climate over Argentina was found. The preferred transitions WR1→WR3 and WR3→WR2 induce sustained cold conditions over Patagonia and over northern Argentina, respectively. The most significant change in precipitation frequency is found for WR3, with wetter conditions over all the analysed regions. Finally, the interannual to interdecadal significant variations in the occurrence of these regimes were discussed. WR1 and WR3 are more frequent and WR2 is less frequent during El Niño, and WR2 and WR5 are more frequent and WR1 is less frequent during La Niña. A significant decrease in WR2 and increase of WR4 and WR5 during the 1970s and early 1980s were found.

Post-mortem analysis of formic acid disposition in acute methanol intoxication Ferrari, Luis Alberto; Arado, Miriam G.; Nardo, Cesar A.; Giannuzzi, Leda Fifteen cases of fatal massive methanol intoxication have been investigated. Victims received either no treatment or ethanol therapeutic treatment. Methanol poisoning cases were classified in three groups according to survival time: more than 3 days (group 1), up to 3 days (group 2) and few hours (group 3). Body distribution of methanol and formic acid, as the main metabolite, was analyzed in blood and in different organs (brain, kidney, lung and liver). Relationships between formic acid concentration in the different tissues, survival time and type of treatment applied to victims were studied. Formic acid in blood and tissues was analyzed by head space gas chromatography (head space-GC) with FID detector, previous transformation in methyl formate, essentially as described by Abolin. Formic acid concentration was between 0.03 and 1.10g/l in the samples under study. A good correlation between blood and brain, but poor between blood and the remaining tissues was found. Obtained data suggested that the use of blood and brain could help to improve the analysis of formic acid intoxication. The best correlation among organs was found between lung and kidney for all groups (r2=0.91, 0.84 and 0.87, corresponding to groups 1, 2 and 3, respectively). Lethality index was defined as LI = (concentration of formic acid in blood in (g/l)/0.5) × 100, taking into account that 0.5g/l is the concentration reported by Mahieu in severe methanol poisoning. LI parameter was used to estimate formic acid incidence on the lethality of methanol poisoning cases. LI showed a good correlation with total formic acid concentration of the different tissues analyzed (r2=0.80). Furthermore, LI allowed us to discriminate between individuals that received therapeutic treatment and survived different periods. LI>100 indicated a severe intoxication and short survival time if the victim was assisted with ethanol therapy and hemodialysis was not applied. With regard to victims who received no therapeutic treatment and died in few hours, LI was in the range 40-100. LI was below 40 for individuals that survived more than 3 days and hemodyalisis was not performed. Results showed the importance of performing formic acid analysis to diagnose severe methanol intoxication in post-mortem cases.

Predictive Functional Control based on Fuzzy Model: Comparison with linear predictive functional control and PID control Lepetic, Marko; Skrjanc, Igor; Chiacchiarini, Hector Gerardo; Matko, Drago The implementation of the fuzzy predictive functional control (FPFC) on the magnetic suspension system is presented in the paper. The magnetic suspension system was in our case the pilot plant for magnetic bearing and is an open-loop unstable process, therefore a lead compensator was used to stabilize it. The high quality control requirements were a-periodical step response and zero steady-state error. Adding the integrator to a feedback causes overshoot. The solution to the problem was cascade control with fuzzy predictive functional controller in the outer loop. To cope with the unknown model parameters and the nonlinear nature of the magnetic system, a fuzzy identification based on FNARX model was used. After successful validation the obtained fuzzy model was used for controller design. The FPFC is compared with a cascade linear predictive functional control (PFC) and PID control. The results we obtained with the FPFC are very promising and hardly comparable with conventional control techniques.

Isotropic and anisotropic components of the neutron emissions at the FN-II and PACO dense plasma focus devices Castillo, F.; Herrera, J. J. E.; Rangel, J.; Milanese, Maria Magdalena; Moroso, Roberto Luis; Pouzo, Jorge Osvaldo; Golzarri, J. I.; Espinosa, G. The average angular distribution of neutron emissions has been measured in the Fuego Nuevo II (FN-II) dense plasma focus device (5 kJ) by means of CR-39 plastic nuclear track detectors. When pure deuterium is used as the filling gas, the data can be adjusted to a Gaussian function, related to anisotropic emission, superposed on a constant pedestal, related to isotropic emission. When deuterium–argon admixtures are used, the anisotropic contribution is best represented by a parabola. The same analysis is applied to previously reported results, for fewer shots, in pure deuterium from the PACO device, which is similar in size to the FN-II. In both devices the anisotropic component is smaller than the isotropic one, but with different features. In PACO the anisotropic component is concentrated on a large narrow beam around the axis, but its contribution to the total neutron yield is significantly smaller than in the FN-II, where the anisotropic component spreads over a wider range. The neutron flux per shot is monitored in both devices with calibrated silver activation detectors, at 20˚ and at 90˚ from the axis. The average values of the neutron flux at these two angles are used, along with the angular distributions obtained form the track detectors, in order to estimate the absolute neutron yield of both the isotropic and the anisotropic contributions. From examining different groups of shots, it is found that the shape of the angular distribution is important in the estimation of anisotropy, and that the value usually reported, as the ratio of neutron counts head-on and side-on, as measured by activation counters, may be misleading.