Absorption and desorption of liquid water by a superabsorbent polymer: Effect of polymer in the drying of the soil and the quality of certain plants

In this work, we were interested in the study of the kinetic behavior of the reaction of drying soil representing the Marrakesh region (south of Morocco) in the presence of an superabsorbent polymer. The presence of a polymer in the soil diminished the kinetic drying of the soil, which will have as an application a reduction in water loss in the process of irrigation. The presence of a polymer in the soil enables a complete modification of the kinetic regimes controlling the soil‐drying kinetic. We also realized the first study of the behavior of certain selected plants in the melange of a soil and a polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 234–243, 2002     

BiNem® manufacturing process for mass production

Abstract— As the need for high‐resolution ultra‐low‐power bistable displays grows, it is important to rapidly implement the mass‐production manufacturing of BiNem® LCDs. The cost‐effective approach for BiNem® manufacturing is based on using STN manufacturing process technologies since BiNem® and STN displays have a similar internal structure. The key differences between BiNem® and STN displays from a manufacturing point of view will be discussed. We show that industrial STN manufacturing equipment can be used to produce BiNem® LCDs at competitive costs. Reflective e‐book display modules with VGA resolution are produced in the pilot‐production series.     

DM1 Transgenic Mice Exhibit Abnormal Neurotransmitter Homeostasis and Synaptic Plasticity in Association with RNA Foci and Mis-Splicing in the Hippocampus

Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disease mediated by a toxic gain of function of mutant RNAs. The neuropsychological manifestations affect multiple domains of cognition and behavior, but their etiology remains elusive. Transgenic DMSXL mice carry the DM1 mutation, show behavioral abnormalities, and express low levels of GLT1, a critical regulator of glutamate concentration in the synaptic cleft. However, the impact of glutamate homeostasis on neurotransmission in DM1 remains unknown. We confirmed reduced glutamate uptake in the DMSXL hippocampus. Patch clamp recordings in hippocampal slices revealed increased amplitude of tonic glutamate currents in DMSXL CA1 pyramidal neurons and DG granule cells, likely mediated by higher levels of ambient glutamate. Unexpectedly, extracellular GABA levels and tonic current were also elevated in DMSXL mice. Finally, we found evidence of synaptic dysfunction in DMSXL mice, suggestive of abnormal short-term plasticity, illustrated by an altered LTP time course in DG and in CA1. Synaptic dysfunction was accompanied by RNA foci accumulation in localized areas of the hippocampus and by the mis-splicing of candidate genes with relevant functions in neurotransmission. Molecular and functional changes triggered by toxic RNA may induce synaptic abnormalities in restricted brain areas that favor neuronal dysfunction.     

Transparent polycrystalline alumina obtained by SPS: Green bodies processing effect

Starting from a commercial slurry of high purity α-Al₂O₃, freeze-dried powders, cast, filter-pressed or cold isostatically pressed samples were produced. Resulting powders or green bodies showing different particles packing were densified by spark plasma sintering (SPS) to obtain transparent polycrystalline α-Al₂O₃. Microstructure and real in-line transmittance (RIT) after SPS were dependent on the particles packing quality. Avoiding large agglomerates, narrowing the pore size distribution, reducing the most-frequent pore size (D_mode) and avoiding macroscopic heterogeneities within the green bodies enabled high RIT values to be achieved in the visible and near-infrared spectrum. However, a limit was achieved in the preparation of green bodies for which reducing the D_mode had no more influence on the optical behaviour of samples sintered by SPS. Finally, pure α-Al₂O₃ samples presenting a high RIT_640 nm value of 53% were produced from all the green bodies obtained by the following techniques: filter-pressing, slip casting and cold isostatic pressing.     

Anisotropie de la decomposition d'un solide. II-mise en evidence d'un gradient thermique dans la phase solide a l'aide d'un thermographe infra-rouge

Monocrystalline platelets of pentahydrate Copper sulfate are submitted to temperature and pressure conditions such that they cause this salt to be converted into a trihydrated salt. Thermal equilibrium of these platelets is ensured before the reaction starts. Temperature is recorded as moving away from the superficial domain undergoing conversion, by means of an I.R. scanning camera fitted with a cooled detecting device. The occurence of a thermal gradient from the reactive solid-solid interface can, thus, be shown. It seems, therefore necessary to take into account the physical properties of the crystal, which are involved in the occurence of thermal gradients in the solid, to explain the anisotropy of this interface displacement during a conversion where a gas is removed.     

Effects of the nature of the doping salt and of the thermal pre-treatment and sintering temperature on Spark Plasma Sintering of transparent alumina

A slurry of α-Al₂O₃ was doped with Mg, Zr and La nitrates or chlorides, in various amounts in the range 150-500 wt ppm and then freeze-dried to produce nanosized doped powder (∼150 nm). The powder was sintered by SPS to yield transparent polycrystalline alpha alumina. The influence of the nature of the doping element and the starting salt, the thermal treatment before sintering and the sintering temperature on the transparency of the ceramics were investigated. The transparency of the ceramics of nanosized Al₂O₃ was shown to depend mainly on the way the powder was prepared, the nature of the doping salt also had an effect. Finally, a high real inline transmittance, reaching 48.1% was achieved after optimization.     

Phase analysis by variable-incidence X-ray diffraction: Application to zirconium oxidation

The oxidation of zirconium at high temperature (T> 400°C) leads to reaction products of two allotropic oxide (ZrO₂ monoclinic and ZrO₂ tetragonal). The distribution and proportion of these two phases were studied as a function of time and space by X-ray diffraction techniques. Quantitative analyses are possible after some corrections, and we demonstrate the presence of a phase gradient in the oxide scale. The interest of this nondestructive method is then discussed.     

Absorption and desorption of liquid water by a superabsorbent polyelectrolyte: Role of polymer on the capacity for absorption of a ground

To study the potentialities of a polyelectrolyte superabsorbent for the storage of water, we have studied a ground representative of the area of Haouz (area of Marrakesh, South of Morocco) in the presence of polymer. We sought the optimal proportions allowing the best retention of water by the mixture made up of the polymer and the ground and to prolong the storage period of water in the ground. We have also studied the effect of certain ions and the pH on the capacity for absorption of polymer. These ions can be naturally present in the ground or introduced by the means of manure and pesticides. The presence of polymer in the ground makes it possible to increase the capacity for absorption of the water by the ground, which can thus involve a saving in water while decreasing the frequency of irrigation and by reducing the water losses by the phenomena of evaporation and infiltration. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1541–1548, 2001     

Influence of plasma cholesteryl ester transfer activity on the LDL and HDL distribution profiles in normolipidemic subjects

The relations of cholesteryl ester transfer protein (CETP) activity to the distribution of low density lipoproteins (LDLs) and high density lipoproteins (HDLs) were investigated in fasting plasma samples from 27 normolipidemic subjects. LDL and HDL subfractions were separated by electrophoresis on 20-160 g/L and 40-300 g/L polyacrylamide gradient gels, respectively. Subjects were subdivided into two groups according to their LDL pattern. Monodisperse patterns were characterized by the presence of a single LDL band, whereas polydisperse patterns were characterized by the presence of several LDL bands of different sizes. To investigate the influence of lipid transfers on LDL patterns, total plasma was incubated at 37 degrees C in the absence of lecithin:cholesterol acyltransferase (LCAT) activity. The incubation induced a progressive transformation of polydisperse patterns into monodisperse patterns. Under the same conditions, initially monodisperse patterns remained unchanged. Measurements of the rate of radiolabeled cholesteryl esters transferred from HDL3s to very low density lipoproteins (VLDLs) and LDLs revealed that subjects with a monodisperse LDL pattern presented a significantly higher plasma CETP activity than subjects with a polydisperse LDL pattern (301 +/- 85%/hr per milliliter versus 216 +/- 47%/hr per milliliter, respectively; p < 0.02). In addition, when total plasma was incubated for 24 hours at 37 degrees C in the absence of LCAT activity, the relative mass of cholesteryl esters transferred from HDLs to apolipoprotein B-containing lipoproteins was greater in plasma with monodisperse LDL than in plasma with polydisperse LDL (0.23 +/- 0.06 versus 0.17 +/- 0.06, respectively; p < 0.02). These results indicated that in normolipidemic plasma, CETP could play an important role in determining the size distribution of LDL particles. The analysis of lipoprotein cholesterol distribution in the two groups of subjects sustained this hypothesis. Indeed, HDL cholesterol levels, the HDL:VLDL+LDL cholesterol ratio, and the esterified cholesterol:triglyceride ratio in HDL were significantly lower in plasma with the monodisperse LDL pattern than in plasma with the polydisperse LDL pattern (p < 0.01, p < 0.01, and p < 0.02, respectively). Plasma LCAT activity did not differ in the two groups. Plasma CETP activity correlated positively with the level of HDL3b (r = 0.542, p < 0.01) in the entire study population. Whereas plasma LCAT activity correlated negatively with the level of HDL2b (r = -0.455, p < 0.05) and positively with the levels of HDL2a (r = 0.475, p < 0.05) and HDL3a (r = 0.485, p < 0.05), no significant relation was observed with the level of HDL3b.(ABSTRACT TRUNCATED AT 400 WORDS)     

Influence of apolipoprotein composition of high density lipoprotein particles on cholesteryl ester transfer protein activity. Particles containing various proportions of apolipoproteins AI and AII

The effect of apolipoprotein (apo) composition of high density lipoproteins (HDL) on cholesteryl ester transfer protein (CETP) activity was studied by measuring the rate of radiolabeled cholesteryl esters transferred between low density lipoproteins (LDL) and HDL3 which contained various proportions of apoAI and apoAII. Ultracentrifugally isolated HDL3, which contained virtually only apoAI and apoAII in their protein moiety, were progressively enriched with apoAII upon the incubation with increasing amounts of delipidated HDL apolipoproteins. The substitution of apoAII for apoAI in HDL3 did not induce marked alteration of the lipid composition of the lipoprotein particles. The rates of cholesteryl ester exchanges with LDL in the presence of purified human CETP were significantly reduced with apoAII-enriched HDL3 as compared with non-enriched homologous particles. Consistent results were obtained by determining the rate of cholesteryl esters transferred either from LDL toward HDL3, or in the opposite direction, from HDL3 to LDL. The effect of the apoAI and apoAII content of HDL particles on CETP activity was also investigated by measuring the rate of cholesteryl esters transferred from LDL to plasma HDL3 particles which contained either only apoAI, HDL3-AI, or both apoAI and apoAII, HDL3-AIAII. HDL3-AI and HDL3-AIAII particles were isolated from human plasma by a sequential procedure which combined ultracentrifugation and anti-apoAII immunoaffinity chromatography. As observed with HDL3 artificially enriched with apoAII, cholesteryl ester transfer rates were significantly lower with plasma HDL3-AIAII than with plasma HDL3-AI particles. Kinetic analysis of the interaction of CETP with apoAII-enriched HDL3 revealed that apoAII could act as an uncompetitive inhibitor of the cholesteryl ester transfer reaction. Since the plasma levels of HDL-AI, HDL-AIAII, and HDL-AII may undergo significant physiological fluctuation, the present study suggests that HDL apoproteins may be important factors in modulating cholesteryl ester transfer rates in vivo.