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En un pequeño porcentaje de pacientes, la estimulación sonora, táctil e incluso nociceptiva en presencia de una ligera profundidad anestésica no provoca la aparición de ondas cerebrales propias de la activación cerebral (ondas α, β), sino que desencadena un enlentecimiento del trazado de las ondas del electroencefalograma.

La tigeciclina es un antibiótico de amplio espectro estructuralmente similar a la minociclina y que comparte algunos de los efectos adversos de las tetraciclinas. Presentamos el caso de una mujer de 68 años que se trató con tigeciclina por una sepsis de origen desconocido y desarrolló al 5.° día de tratamiento un cuadro sugerente de pancreatitis aguda con dolor abdominal junto con elevación de enzimas pancreáticas. Tras descartar diferentes etiologías y basándonos en la escala de Naranjo para la probabilidad de reacciones adversas a fármacos, la tigeciclina fue la causa probable de la pancreatitis aguda, complicación de la cual ha habido 5 comunicaciones en la base de datos del sistema español de farmacovigilancia desde 2009. Se recomienda una vigilancia estrecha de signos y síntomas abdominales durante el uso de tigeciclina, ya que los efectos adversos en el aparato digestivo son los más prevalentes con este fármaco.

The deactivation pathways of a zeolite H-ZSM-5 catalyst containing bentonite and α-Al2O3as binder material have been studied during the transformation of chloromethane into light olefins, which is considered as a possible step to valorize methane from natural gas. The reactions have been carried out in a fixed bed reactor, feeding pure chloromethane at 400, 425 and 450 °C, 1.5 bar and with a space-time of 5.4 (gcatalyst) h (molCH2)−1for 255 min. The properties of the fresh and spent catalysts have been assessed by several techniques, such as N2physisorption, adsorption/desorption of NH3, XPS and 29Si NMR. Additional measurements of the spent catalysts have been performed to study the nature of the deactivating coke species: TG-TPO analysis, SEM, and FT-IR and UV-vis spectroscopy. With the results in hand, two deactivation mechanisms were proposed: irreversible dealumination at temperatures higher than 450 °C by HCl and reversible coke fouling, while coke formation results from the condensation of polyalkylbenzenes, which are also intermediates in olefin production. The coke deposits grow in size with the addition of Cl to the carbonaceous structure.

The effect of temperature has been studied in hydrocracking of light cycle oil (LCO), byproduct of fluidized catalytic cracking (FCC) units on a bifunctional catalyst (Pt‐Pd/HY zeolite). The increase in both temperature and H2partial pressure have an important attenuating effect on catalyst deactivation, given that they decrease sulfur equilibrium adsorption and enhance hydrocracking of coke precursors. Therefore, the catalyst maintains significant hydrodesulfurization and hydrocracking activity. As the temperature is increased, hydrocracking conversion and naphtha selectivity increase, although there is no significant dearomatization of the medium distillate fraction in the range of the studied experimental conditions. 400 °C is the more suitable temperature for obtaining a high yield of naphtha with a high content of i‐paraffins.

The performance of a draft‐tube conical spouted bed for drying fine particles under batch operating conditions has been assessed at several temperatures using nonporous and open‐sided draft tubes, and the results have been compared with those obtained when operating without a draft tube. In order to ascertain the influence of temperature on drying, experimental runs have been carried out in the 25–300 °C temperature range. The open‐sided draft tube provides the best performance due to the excellent gas‐solid contact attained with this device, which enables shorter drying times. A maximum air temperature of 200 °C is recommended for energy optimization. An open‐sided tube protruding above the stagnant bed by at least 2/3 of the latter's height produces much lower and denser fountains than a tube flush with the upper surface of the bed.

About 20% of familial amyotrophic lateral sclerosis (ALS) is caused by mutations in SOD1and is typically transmitted as an autosomal dominant trait. However, due to reduced mutation penetrance, the disease may present in a recessive or sporadic manner.

Spout diameter has been measured in shallow spouted beds by means of an optical fiber probe, for different geometric factors of the contactor (base angle and gas inlet diameter) and under different experimental conditions (stagnant bed height, gas velocity, particle density, particle size, and particle shape). The study has been performed with glass beads and low-density solids (high and low-density polyethylene, polypropylene, and extruded and expanded polystyrene). A correlation that is valid to predict the average spout diameter in cylindrical spouted beds for beds composed of solids of different density, size, and shape has been developed that is in agreement with the experimental data. This equation is interesting for the proposal of real models for gas−solid flow.

The transformation of methanol into olefins over SAPO-18 catalyst in the 250−450 °C range has been studied. The process has been analyzed by following the evolution with time on stream of the mass deposited on the catalyst, of the heat flow evolved, and of the product formation, which are analyzed by means of on-line mass spectroscopy. The results are in agreement with the “hydrocarbon pool” mechanism, and show that the process is conditioned by an initiation step in which the reactive intermediates for the production of olefins are generated. These intermediates are trapped in the SAPO-18 cages. As time on stream is increased, the steps of initiation, maximum production of olefins, and deactivation develop, and the duration of these steps depends on reaction conditions. Water content in the feed has an important attenuating effect on the methanol adsorption and delays the generation of the active intermediates, and also attenuates the subsequent degradation of the intermediates to coke. This attenuation of coke formation is of great importance for reducing catalyst deactivation.

The kinetics of the pyrolysis of tire material has been studied in a conical spouted bed reactor (CSBR), in the range between 450 and 600 °C, for two particle size ranges (between 0.1 and 0.8 mm and between 0.8 and 4.0 mm). The kinetic results have been compared with those obtained for the same material with other technologies, namely, thermogravimetry and a fast heating microreactor. This comparison and the one carried out with the literature results for similar materials have permitted the analysis of the effect of the technology and of the experimental conditions of pyrolysis (especially particle size) on the kinetic results. It has been proven that the CSBR is especially suitable for the kinetic study of these materials, as it allows for obtaining an excellent gas−solid contact, which minimizes the limitations of heat and mass transfer and maintains bed isothermallity at high temperatures, within the temperature ranges and heating rates of interest for scaling-up. In the pyrolysis of small particles (between 0.1 and 0.8 mm), the apparent activation energy is 121.3 kJ mol^-1 and the corresponding frequency factor is 1.0 × 10⁶ s^-1. The effect of particle size is significant and shows the impossibility of totally avoiding the limitations of heat and mass transfer in the pyrolysis of these materials.

The effect of the geometric factors of the contactor and of the operating conditions on the geometry of the spout and fountain has been studied by means of an optical fiber probe. In the fountain, the core or solid ascending zone and the periphery or solid descending zone have been delimited. The materials studied are glass beads and different plastics (polyethylene, polypropylene, and polystyrene, both extruded and expanded). A correlation proposed for the calculation of the average spout diameter in cylindrical spouted beds of a conical base has been proven to be valid for these materials of low density. New correlations are proposed for the calculation of the height and width of the fountain.

The combined effect of both the water content in the reaction medium and the reaction temperature (in the 400−500 °C range) on the acidity deterioration of a HZSM-5 zeolite catalyst in the methanol to olefins process has been studied. Accordingly, the catalyst has been used in reaction-regeneration cycles in an isothermal fixed-bed reactor. The nature of the acid sites has been measured by means of Fourier transform infrared of the pyridine adsorbed. Both the total acidity and the acid strength distribution of the sites have been determined by calorimetric measurements of differential scanning of adsorption of ammonia and temperature-programmed desorption of this base. The results are proof of the irreversible loss of acidity at 450 °C for a water content in the feed above 50 wt %. Irreversible deactivation occurs at 500 °C from low values of conversion, even when pure methanol is fed.

Celiac disease (CD) is an autoimmune enteropathy that develops in genetically susceptible individuals exposed to gliadin. Early diagnosis of CD may reduce the risk of complications, and several studies have related the duration of gluten exposure to the risk of other autoimmune diseases. It has been proposed that silent CD be diagnosed as soon as possible to avoid potential complications. The purpose of this study was to determine the prevalence of CD among children less than 3 years and to provide treatment to those patients diagnosed with CD. Parents of 1100 healthy children born between October 1998 and December 1999 were asked at the time of delivery to enroll their children in a program for the early diagnosis of CD. The parents of 830 children agreed to participate. Patients in the study were examined and anti–tissue transglutaminase antibody was first measured at about 1.5 years of age. A second antibody titer was obtained at about 2.5 years of age. Patients with detectable autoantibodies underwent intestinal biopsy for confirmation of CD. Of the 830 children initially enrolled, 613 and 484 returned for the first and second visits, respectively. None had anti–tissue transglutaminase antibodies at the first visit, but 9 had anti–tissue transglutaminase immunoglobulins at the second visit. In 7 of these 9, intestinal biopsy confirmed the diagnosis of CD which suggests a minimum prevalence of CD of 1 per 118 healthy newborns. The authors observed a very high prevalence of CD, comparable to that observed in other European populations, which might even be higher if all of the children initially examined had returned for their second visit. If general screening for CD were accepted, the authors would recommend age 2–3 years as the best time for measuring tissue transglutaminase antibodies.

A study has been made of the effect of both the geometric factors of the contactor (base angle and gas inlet diameter) and the experimental conditions (stagnant bed height, particle diameter, and gas velocity) on the trajectories of the particles in the three zones (spout, annulus, and interface) of spouted beds. The trajectories have been determined from the experimental results of the vertical component of the particle velocity measured by means of an optical fiber probe. Cycle time distributions have been calculated from the trajectories, and they have been compared with the experimental results obtained by monitoring colored particles using video-imaging treatment. Original correlations have been proposed for calculating the average cycle time from the geometric factors and experimental conditions.

The catalytic transformation over a HZSM-5 zeolite of key components of the liquid product obtained by the flash pyrolysis of biomass, namely, acetaldehyde, ketones (acetone and butanone), and acetic acid, has been studied, and great differences in reactivity and degradation to coke have been found. Acetaldehyde has a low reactivity to hydrocarbons, with a noticeable deactivation caused by coke deposition, which can be attributed to its capacity for oligomerization with the trimer trimethyltrioxane obtained as an intermediate product. The transformation of ketones [less reactive than the alcohols studied in part I of this work (see the preceding paper in this issue)] and of acetic acid (which gives rise to acetone as the primary product) mainly occurs through decarboxylation and, to a lesser degree, dehydration. Above 400 °C, this transformation gives olefins and aromatics according to a reaction scheme similar to that better known for the reaction of alcohols. The generation of coke (attenuated by the presence of water in the reaction medium) is more significant than in the corresponding process for alcohols, and it limits the formation of aromatics and increases the formation of olefins (intermediate products of the reaction scheme).

The effects of temperature and space time on the transformation over a HZSM-5 zeolite catalyst of several model components of the liquid product obtained by the flash pyrolysis of vegetable biomass (1-propanol, 2-propanol, 1-butanol, 2-butanol, phenol, and 2-methoxyphenol) have been studied. The transformation of alcohols follows a route similar to that of methanol and ethanol toward the formation of hydrocarbon constituents of the lumps of gasoline and light olefins. Phenol and 2-methoxyphenol have a low reactivities to hydrocarbons, and the deposition of coke of thermal origin caused by the condensation of 2-methoxyphenol is noticeable. The generation of catalytic coke and the deactivation by this cause attenuate as the space time and water content in the feed are increased. To avoid the irreversible deactivation of the HZSM-5 zeolite, operations must be carried out at a temperature below 400 °C. Above this temperature, the increase in product aromaticity is also significant.

The effect of the operating conditions (base angle, air inlet diameter, stagnant bed height, particle diameter, and air velocity) on the fountain geometry (height and amplitude) has been studied. Likewise, particle ascending and descending zones in the fountain have been delimited. These studies have been carried out by means of an optical fiber and by an image treatment system. An equation has been proposed for the calculation of the fountain height from the vertical component of the particle velocity in the axis at the base of the fountain. The contactor base angle has a major incidence on the fountain geometry. The external diameter of the fountain and that of the core are conditioned by the diameter of the spout at the base of the fountain. The diameter of the core (or ascending zone) decreases with the fountain level for all experimental conditions.

A study has been carried on the applicability of correlations previously proposed for the design of conical spouted beds, for the treatment of materials of density similar to that of glass, and for the handling of plastic materials (polyethylene, polypropylene, and extruded and expanded polystyrene). The correlations proposed allow for calculation of the geometric factors (angle and design of the base) of conical spouted beds for stable operation, the minimum velocity for spouting and dilute spouting, the operating pressure drop in both regimes, the peak pressure, the bed voidage, and the evolution of this voidage as the gas velocity is increased between the regimes of a spouted bed and a dilute spouted bed.

The MHC class I chain-related A gene (MICA) is expressed in gastrointestinal epithelium and functions as an immune activation signal under stress conditions. MICA protein binds to NKG2D, a receptor of γ δ T cells containing the TCR variable region Vδ1, which are the most abundant subset of T cells in the intestinal epithelium. Ingested gluten in patients with celiac disease (CD) may function as a stress signal for the epithelial cells, and could enhance MICAexpression on their surface. In this study, we have analyzed MICAexpression in intestinal biopsy specimens from newly diagnosed and treated CD patients and controls. Quantitative RT-PCR analysis did not show differences in MICAexpression among the three groups. With these results, we conclude that overexpression of MICAdoes not seem to play an important role in the pathogenesis of CD, at least at the time of diagnosis.

The VNTR region located at the 5'-end of the insulin gene on chromosome 11p15.5 is linked to susceptibility to type 1 diabetes mellitus (T1DM), and class I alleles have been associated with increased risk of disease, whereas class III alleles are considered to be protective. Although a potential effect on the expression level of thymic insulin and a consequent abnormal tolerance have been proposed as an explanation, it is still not clear whether the association is specific for T1DM or whether it is shared by other autoimmune disorders. To investigate the contribution of INS-VNTR to the genetic susceptibility to autoimmune disorders, we analyzed 102 autoantibody-positive T1DM patients, 59 patients with celiac disease (CD), and 57 patients with Addison's disease (ADD), as well as 111 unrelated healthy individuals from the general population. When analyzing the results, class I allele frequencies were 85.8 in the T1DM group, 77 among CD patients, 71 in the ADD group, and 76.1 in the general population. Association with increased risk was seen only in the T1DM group (pc 0.015). Risk to T1DM was associated with the class Iclass I homozygous genotype (RR, 1.92; 95 CI, 1.03-3.6). In conclusion, INS-VNTR does not seem to be involved in the susceptibility to autoimmune diseases other than T1DM and can be considered a diabetes-specific locus.

Autoimmune disorders such as type 1 diabetes (T1DM), celiac disease (CD), and Addison's disease (ADD) develop in individuals with genetic susceptibility that are exposed to environmental triggering factors not completely defined. Patients with an autoimmune disease (and their relatives) are at increased risk of developing another disorder, and this might be caused by a common genetic origin of autoimmunity; for example, HLA class II region in 6p21 shows a very strong association with most diseases. The aim of this study was to determine whether shared susceptibility markers extend from the central (DRB1) through the telomeric (MICA) HLA region. We analyzed three independent sets of families with one autoimmune disease, T1DM, CD, or ADD, and genotyped them for HLA-DRB1 and for the exon 5 GCT polymorphism of MICA. For HLA-DRB1, allele DRB10301 was the only one associated with risk for all three diseases; in the case of MICA, allele A9 was found to be the common protective allele. Haplotype analysis shows that haplotype A5.1-DRB10301 confers risk to autoimmunity. Our results show that there are common risk and protection alleles in both loci, suggesting a core of genetic association with autoimmunity (HLA-DRB10301 risk; A9 protection) that could be modulated by other allelesloci or environmental factors toward one or another disease. Some alleles are part of conserved haplotypes (A5.1-DR3, A5.1-DR2), whereas others seem to have independent effect (A9) and support the idea of two independent loci in this region.

The conversions and yields of the fractions of gases (C1, C2), LPG (C3, C4), gasoline (C5−C12), and coke and their compositions have been studied in the catalytic cracking of blends made up of polystyrene and polystyrene−butadiene with a LCO (light cycle oil, which is a secondary refinery product) used as the solvent. The catalysts were prepared from HZSM-5 zeolites of different total acidities. The reaction was carried out in the 450−550 °C range and under the standard conditions of FCC units. The important effects both of the total acidity of the zeolite and of the temperature on the conversion and yield of styrene are demonstrated. Total recovery of the monomer styrene is attained at 550 °C. Likewise, the LCO is valorized, as high yields of both the C5−C12 aromatic fraction and LPG (olefinic) are obtained with low yields of gases (C1, C2) and coke.

The effects of a sweeping treatment on the activity recovery, coke content, H/C ratio, and kinetics of coke combustion have been studied in the coke deposited on an HZSM-5 zeolite. The reaction test studied is the transformation of acetone into hydrocarbons at 400 °C, and the gases used in the sweeping are He, H2, and steam. Aside from the partial elimination of coke, which occurs with all these gases, each one has a different effect. Thus, sweeping with H2 causes catalyst rejuvenation. Sweeping with He promotes coke aging and a reduction in the H/C ratio. Steam is efficient for coke elimination but causes dealumination. The combustion of the remaining coke is disfavored (the activation energy is increased, and the kinetic constant is decreased) by the sweeping treatment that decreases the H/C ratio of the coke.

A study has been made of the valorization of polyolefins, PE (polyethylene) and PP (polypropylene), dissolved in LCO [light cycle oil obtained as a product stream in a fluid catalytic cracking (FCC) unit] by their cracking on three catalysts prepared based on HY zeolites of different acidity and different porous structure. The reaction has been studied in the 450−550 °C range and under conditions similar to those of the FCC. The determining factor in the performance of the catalyst is the accessibility of the acid sites by the dissolved macromolecular chains, where a moderate acidity of the zeolite is sufficient. Whereas a feed of dissolved PE contributes to a decrease of the yield of coke with respect to that corresponding to the cracking of LCO, a feed of PP increases the yield of coke. The optimum temperature for maximizing the yield of gasoline, and minimizing that of coke, is 450 °C. The gasoline fraction (C5−C12) is mainly aromatic with C8+ components. The stream of gaseous products is largely made up of propylene and butenes.

Celiac disease (CD) is an autoimmune disorder caused by intolerance to ingested gluten that develops in genetically susceptible individuals. The contribution of human leukocyte antigen (HLA) genes to the genetic risk to CD has been known for a long time; however, non-HLA genetic factors are likely to be required for the development of the disease. Several studies have associated the CD28/CTLA4region on chromosome 2q33 with the disease in different populations. The CTLA4gene encodes a receptor involved in the control of T-cell proliferation and mediates T-cell apoptosis. To determine the contribution of two polymorphisms of the CTLA4to the disease: the A/G dimorphism at position +49 in exon 1 and the (AT)nmicrosatellite in the 3´ untranslated region. Forty-one celiac families of Basque origin (43 patients with CD and 80 first-degree relatives). Restriction enzyme digestion of polymerase chain reaction amplified genomic DNA for the A/G dimorphism and polymerase chain reaction followed by high-resolution electrophoresis for the (AT)nmicrosatellite. For disease association studies, the Affected Family Based Controls approach was used. The frequency of the A allele of 49 A/G polymorphism was 67.47% in the celiac allele group compared with 70.13% in the Affected Family Based Controls group. These differences were not significant. Analysis of the (AT)npolymorphism identified 17 different alleles, ranging from 262 to 312 bp in length, but no allele was significantly associated with the disease. Our results did not show any evidence of association of any of the CTLA4gene polymorphisms with the disease. This may result from population-specific differences in genetics and environmental susceptibility to CD.

Bifunctional catalysts for the transformation of carbon dioxide and hydrogen into gasoline have been prepared by conventional and novel processes and characterized by measurement of BET surface area and volume and distribution of pores, and by X-ray diffraction, FTIR spectroscopy and X-ray fluorescence. The effects of the preparation conditions and of the atomic ratios between the metals on the structure and on the properties of the catalysts were studied.
© 2003 Society of Chemical Industry

Kinetic results of polyolefin (polyethylene and polypropylene) pyrolysis obtained in a conical spouted bed reactor are compared with those obtained by thermogravimetry and in a high-heating-rate microreactor. The results are evidence of the good performance of this original reactor for kinetic studies of flash pyrolysis of plastics at high temperatures, which is due to bed isothermicity and to the fast and uniform coating of sand particles with melted plastic and, consequently, to lower limitations of heat and mass transfer. Agglomeration problems are minimum in this reactor, which is due to the good gas−solid contact in the spouted bed and to the vigorous particle movement attained with the conical geometry of the reactor.

Basic aspects (coke deposition, acidity deterioration) of the deactivation by coke of a catalyst (prepared from a HZSM-5 zeolite) used in the transformation of aqueous ethanol into hydrocarbons in the 350−450 °C range have been studied. The experiments were carried out in an isothermal fixed-bed reactor with feeds of ethene, mixtures of ethanol and water at different mass ratios, and diethyl ether. The importance of temperature and water content in the reaction medium on the mechanism of coke evolution is demonstrated. The effect of these variables on deactivation is explained by a kinetic model in which the role of coke precursors (ethene, light olefins, and gasoline) is considered. This role depends on the operating conditions, particularly the temperature.

The maximum genetic susceptibility to type 1 diabetes (T1DM) in Basques is conferred by extended HLA haplotype F1C30-DR3-DQ2-DPB10202. Due to the strong linkage disequilibrium within the haplotype, it is difficult to determine which individual allele shows the strongest association with T1DM. Recent studies of the MIC-Agene have shown an HLA-independent association of allele A5 with T1DM and A5.1 with Addison's disease. In order to test for association of the MIC-Aexon 5 polymorphism with T1DM and to further characterize risk and protection haplotypes in Basques, we typed 70 Basque families with T1DM for MIC-Aexon 5 polymorphism using fluorescent PCR and electrophoresis on an ABI sequencing machine. When analyzed individually, allele A4 was associated with disease [OR 2.93 (1.58-5.5)], while the presence of A9 conferred protection from T1DM [OR 0.27 (0.08-0.74)]. In the context of HLA haplotypes, allele A4 was found to be associated to the F1C30-DR3-DQ2-DPB0202 risk haplotype, both for T1DM and AFBAC alleles ( Pc 0.0003 ). Allele A5.1 was strongly associated with protective haplotype SC31-DRB11501-DQB10602, present only in AFBAC alleles, but also with risk haplotype SC01-DR3-DQ2. In conclusion, polymorphisms in exon 5 of the MIC-Agene are associated with genetic susceptibilityprotection to T1DM, but in the context of susceptibility HLA haplotypes. Nevertheless, the protective effect of A9 allele seems independent from HLA, since it does not appear to be associated with any particular extended haplotype.

With the aim of determining the possibilities of directly upgrading the liquid obtained from carbohydrate fermentation, the effect of operating conditions (temperature, space time, water content in the feed) has been studied in the catalytic transformation of aqueous ethanol into hydrocarbons on an HZSM-5 zeolite in an isothermal fixed bed reactor. Special attention has been paid to the effect of water content on the yield, product distribution and catalyst deactivation. Although deactivation by coke decreases as the water content is increased, this content must be limited at 450 °C and higher temperatures in order to avoid irreversible deactivation of the catalyst by dealumination.
© 2002 Society of Chemical Industry

AbstractWe review the application of some fundamental concepts of discrete convex analysisto cooperative game theory, as well as several representations of n-person cooperative games by convex functions of nvariables.

A simulation model has been proposed and used to predict the behavior of a laboratory pseudoadiabatic reactor for the transformation of methanol into hydrocarbons. The model incorporates recent advances in the kinetic modeling of the main reaction steps and of the deactivation by coke of the catalyst in the 350−450 °C range and is efficient for analyzing the effect of process conditions (space time, water content and inert gas in the feed, and inlet temperature) on the evolution with time on stream of the temperature profile along the reactor and on the yields of the product lumps.

A kinetic model for the transformation of aqueous ethanol into hydrocarbons on a HZSM-5 zeolite has been proposed for the 623−723 K range on the basis of experiments carried out in an isothermal fixed-bed reactor with feeds of ethene, ethanol−water mixtures of different mass ratios, and diethyl ether. The kinetic model is of interest for directly upgrading the liquid product obtained by the fermentation of carbohydrate wastes. It is based on the latest progress made in the catalytic transformation of methanol and quantifies the attenuating effect of water in the reaction medium in all the steps of the kinetic scheme.

An original reactor (a conical spouted bed reactor) is used for the kinetic study of Pinus insignis sawdust pyrolysis in the range 400-500 °C under the usual conditions of this reactor for pyrolysis in a continuous regime. The equipment meets the requirements for pyrolysis kinetic study (bed isothermality, high mass and heat transfer between phases and short residence time of gaseous products). The results of yield of products are evidence of the good performance of the conical spouted bed reactor for obtaining a liquid product, with a maximum yield of 70 wt% in the range 440-460 °C.
© 2001 Society of Chemical Industry

The effect of operating conditions (base angle, gas inlet diameter, stagnant bed height, particle diameter, and gas velocity) on longitudinal and radial profiles of bed voidage has been studied in the spout, annulus, and both the fountain core and periphery of spouted beds, by means of an optical fiber probe. Correlations are proposed for calculation of the local bed voidage in spout and annular zones, along the spout axis and in proximity to the contactor wall.

The effect of the operating conditions (base angle, gas inlet diameter, stagnant bed height, particle diameter, and gas velocity) on spout geometry has been studied in shallow spouted beds by means of an optical fiber probe. The experimental results have been fitted to an empirical equation for calculation of the average spout diameter in shallow spouted beds. The proposed equation takes into account the effect of base angle and gas inlet diameter, which are parameters that have not been previously taken into account in the literature (for deep beds) and have a great importance in the generation of the spout in shallow spouted beds.

Over the last few years several studies of linkage between non-HLA loci and type I diabetes mellitus have mapped several putative susceptibility genes on chromosome 6q; in fact, positive evidence of linkage and/or association of JDDM5 (6q25), IDDM8 (6q27) and IDDM15 (6q21) with type 1 diabetes has been reported. We have studied these loci in diabetic families of Basque origin, a genetically homogeneous population, to avoid artifactual association results due to admixture within the sample analysed. Statistical analyses of linkage were performed using a transmission disequilibrium test (TDT). We could not confirm linkage for IDDM5, IDDM8 and IDDMI5 in our population, possibly due to population-specific differences in genetic susceptibility and/or environmental triggering factors to type 1 diabetes

Background:We evaluated the efficacy and safety of CO2wedged hepatic venography (CO2WHV) by comparing it with direct transjugular (DP) and indirect arterial portography (IP). Methods:Twenty-one CO2WHV and IP examinations were performed in 20 patients; 13 of them also underwent DP within 48 h of CO2WHV and IP. IP involved the injection of iodinated contrast into the superior mesenteric and splenic arteries. DP was performed from a transjugular approach, during transjugular intrahepatic portosystem shunt placement, with the injection of iodinated contrast into the superior mesenteric or splenic vein. The parameters evaluated were visualization of vessels and varices, portal vein thrombosis detection, and complications. Results:CO2WHV depicted the splenic vein in 57%, the superior mesenteric vein in 62%, the main portal vein in 90%, the right portal vein in 95%, and the left portal vein in 90% of patients. It also demonstrated gastroesophageal varices in seven cases, a splenorenal shunt in one case, mesenteric varices in one case, and a recanalized umbilical vein in one case; other varices were also seen. Conclusion:CO2WHV is a good and safe technique for demonstrating the portal circulation. It may provide information not obtainable by IP and DP. However, IP provides better demonstration of the variceal network. RID="" ID="" Correspondence to: A. Martínez-Cuesta

The kinetic behavior has been studied for cracking a commercial feedstock on a hybrid catalyst (with 5 wt % of HZSM-5 zeolite) made up of 80 wt % of a catalyst equilibrated in a fluid catalytic cracking (FCC) unit and of 20 wt % of a catalyst prepared based on a HZSM-5 zeolite. A laboratory-scale reactor which allows for operation under conditions similar to those of commercial FCC units has been used. From the analysis of the gases and gasoline obtained in the 500−550 °C range, with contact times between 2 and 10 s and for a catalyst/feedstock = 6, the influence of HZSM-5 zeolite presence in the catalyst on gas and gasoline composition and on gasoline research octane number has been analyzed.

The performance of original equipment provided with a conical spouted bed reactor has been studied in flash pyrolysis of sawdust with an inert gas (N2) in the 350−700 °C range and with 50 ms of average gas residence time. The effect of pyrolysis temperature on the yields of gas, liquid, and char on gas and liquid composition and on char properties has been studied. The maximum yield of liquid (corresponding to 70 wt %) is obtained at 450 °C and its composition determined by GC/MS is similar to that reported in the literature for bubbling fluidized beds. Although temperatures above 600 °C are required for the development of the char porous structure, the yield of CO2 obtained under these conditions is unacceptable.

A kinetic model for the methanol to olefins (MTO) process on a catalyst based on a silicoaluminophosphate SAPO-34 has been proposed. The model takes into account four individual steps for the production of ethene, propene, butenes, and remaining hydrocarbons (pentenes + paraffins). The kinetic parameters have been obtained by experimentation in an isothermal fixed-bed reactor, in the 623−748 K range. In virtue of the results, it has been proven that the water introduced in the feed (required for attenuation of coke deactivation) inhibits olefin formation. This inhibition is taken into account in the kinetic model.