Tailoring 2D and 3D molecular sieves structures for polyolefin composites: do all roads lead to remarkable performances?

Multiple synthetic strategies were performed in order to tether a zirconium-based catalyst to the 2D and 3D molecular sieves for olefin polymerizations. The anchoring of fluorene silane to the mesoporous MCM-41 was performed in order to obtain a stable catalyst for olefin polymerization (1@MCM-41). Using spectroscopic methods, this system was shown to have the metal center locked on a face down conformation with the surface. Also, immobilized zirconium complexes have been prepared on three different types of aminopropyl-modified supports (2@magadiite, 2@MCM-41 and 3@MCM-48). The advantage of this latter method of immobilization would be the reduction of the steric effect caused by the support: the catalyst, distant from the surface, is more exposed to the monomer and this situation may lead to an increase in the catalytic activity compared to 1@MCM-41. However, a medium size chain as a spacer between the support and the metallocene is still flexible enough to bend and predisposes the metal center to interact with the support surface; this effect is more evident when the nature of the support is of fixed pore dimensions. These supported catalysts exhibited activity for ethylene polymerization, resulting in linear PEs with high melting temperatures. In order to retain a metallocene assembled as in a homogeneous environment, a multi-step reaction was investigated (4@magadiite) but it led to the leaching of the organic moieties from the surface during catalyst preparation. The best catalytic performance was achieved when homogeneous Oct-amido catalyst (5) was reacted with the surface of magadiite and n-alkyl-AlPO-kan.

First Report of 'Candidatus Liberibacter solanacearum' Naturally Infecting Tomatoes in the State of Mexico, Mexico.

In January 2011, tomato (Solanum lycopersicum) plants exhibiting stunting, yellow mosaic, short, chlorotic leaves, aborted flowers, and reduced-size fruits, symptoms similar to those exhibited by plants infected by 'Candidatus Liberibacter solanacearum' (2), were observed in approximately 5% of tomato plants in greenhouses in Jocotitlan in the State of Mexico, Mexico. Occasional plant recovery was also observed. Tomato plants in this facility were previously shown to be infected by Mexican papita viroid (MPVd), Pepino mosaic virus (PepMV), and aster yellows phytoplasma. Eight symptomatic leaf samples (designated MX11-01 to MX11-08) were collected and screened against selected tomato viruses and pospiviroids by reverse transcription (RT)-PCR using purified plant RNA or for 'Ca. L. solanacearum' by PCR using purified plant DNA. As expected, both PepMV and MPVd were detected in these samples. However, two 'Ca. L. solanacearum'-specific PCR products (1,168 and 669 bp) were also amplified in two samples (MX11-02 and MX11-05) using primers OA2 (2) and OI2c (1) or CL514F/CL514R (3), respectively. Each 'Ca. L. solanacearum'-specific PCR product was gel purified with Geneclean (Q-Biogene, Carlsbad, CA) and cloned into pCR2.1 using TOPO TA cloning kit (Invitrogen, Carlsbad, CA) and sequenced (Functional Biosciences, Madison, WI). Sequences of 16S rRNA (1,168 bp) in both isolates (GenBank Accession Nos. JF811596 and JF811597) were identical. However, the 669-bp 50S rRNA sequences in these two isolates (GenBank Accession Nos. JF811598 and JF811599) contained two single nucleotide polymorphism (SNP) mutations. BLASTn searches showed that both 16S rRNA and 50S gene sequences in MX11-05 were identical to the 'Ca. L. solanacearum' previously identified on potato in Chihuahua (GenBank Accession Nos. FJ829811 and FJ829812) and Saltillo (GenBank Accession Nos. FJ498806 or FJ498807) in eastern Mexico. These 'Ca. L. solanacearum' isolates were recently classified as the "b" haplotype (4). Alignment analysis of the 'Ca. L. solanacearum' 16S rRNA sequences also revealed the conserved SNP mutations (g.212T > G and g.581T > C) in MX11-02 and MX11-05 as previously identified for other "b" haplotype isolates (4). 'Ca. L. solanacearum' was first identified in greenhouse tomatoes in 2008 in New Zealand (2). It has also been identified in greenhouse and field tomatoes in the United States. 'Ca. L. solanacearum' was previously reported to infect field tomatoes in Sinaloa, Mexico (3), which was recently considered as the "a" haplotype (4). To our knowledge, this is the first report of 'Ca. L. solanacearum' naturally infecting tomatoes in Jocotitlan in the State of Mexico, Mexico. The greenhouse tomato 'Ca. L. solanacearum' may be transmitted from infected solanaceous plants by potato psyllids (Bactericera cockerelli), which were observed in this facility. References: (1) S. Jagoueix et al. Int. J. Syst. Bacteriol. 44:379, 1994. (2) L. W. Liefting et al. Plant Dis. 93:208, 2009. (3) J. E. Munyaneza et al. Plant Dis. 93:1076, 2009 (4) W. R. Nelson et al. Eur. J. Plant Pathol. 130:5, 2011.

Long-term survivors of pediatric heart transplantation: a multicenter report of sixty-eight children who have survived longer than five years.

OBJECTIVE: Short-term survival after pediatric heart transplantation is now excellent, but ultimately the efficacy of this procedure will depend on duration and quality of survival. We sought to evaluate the clinical course of long-term survivors of heart transplantation in childhood. METHODS: Patients who had undergone heart transplantation at the university hospitals of Stanford, Columbia, and Pittsburgh between 1975 and 1989 and survived longer than 5 years from transplantation were identified and their clinical courses retrospectively reviewed. RESULTS: Sixty eight children have survived more than 5 years from transplantation, and 60 (88%) are currently alive with a median follow-up of 6.8 years (5 to 17.9 years). Thirteen have survived more than 10 years from transplantation. Renal dysfunction caused by immunosuppressive agents was common, and two patients required late renal transplantation. Lymphoproliferative disease or other neoplasm occurred in 12 patients, but none resulted in death. Coronary artery disease was diagnosed in 13 patients (19%), leading to retransplantation in eight. Death after 5 years was related to acute or chronic rejection in 5 of 8 cases. Two of the deaths were directly related to noncompliance with immunosuppressive medication. All survivors are in New York Heart Association class 1. CONCLUSIONS: Long-term survival with good quality of life can be achieved after heart transplantation in childhood, though complications of immunosuppression remain common. Posttransplantation coronary artery disease is emerging as the main factor limiting long term graft and patient survival.

The distribution of F13A subtypes in four populations using agarose isoelectric focusing and Western Blot detection.

Using an isoelectric focusing gel containing agarose, urea, a separator and a narrow range ampholyte of pH 5-6, a system was designed to split the F13A*1 and F13A*2 alleles into the subtypes 1A, 1B, 2A and 2B. Four population groups (European-Americans, African-Americans, Mexican-Americans and Native-Americans) were data based. Subtyping F13A increased the information content significantly over the previous F13A typing system by doubling the number of alleles and increasing the number of phenotypes from three to ten. The new system has proved to be of value in parentage testing by increasing exclusionary power in cases of non-paternity and increasing the paternity index in non-exclusionary cases. Though there does not appear to be any significant variation among U.S. populations, published data on Japanese populations suggests that significant differences among populations may exist, leading to an anthropological usefulness as well.

Simultaneous subtyping of group specific component and esterase D by isoelectric focusing on agarose gels.

A quick, sensitive and economical technique has been developed to subtype GC and ESD simultaneously on the same agarose IEF gel. This method could be a useful tool for forensic application.

Influence of supplementation on the dental caries incidence and growth of rats fed two model diets.

In order to improve the quality of caries-promoting diets MIT 200 and NIH 2000, both diets were supplemented with fat. In addition, the NIH 2000 diet was supplemented with minerals and vitamins. Supplementation with essential nutrients improves the quality of the diets and enhances growth when compared to control animals. Adding minerals and vitamins to diet NIH 2000 abolishes loss of pigmentation of incisors, improves hemoglobin and hematocrit and reduces caries scores in the buccal surfaces by 50% when compared to the non-supplemented diet. It is possible that the cariogenic properties of diet NIH 2000 may be a function in part of a nutrient deficiency.

Influence of dietary iron on the dental caries incidence and growth of rats fed an experimental diet.

In view of the fact that supplementation with essential nutrients improves the quality of diet NIH 2000 and enhances growth, this study was carried out to determine the effects of supplementation with a specific nutrient. Diet 2000 was supplemented with 35 ppm of FeSO4 and fed ad libitum for 40 days. Iron supplementation reverses the caries process and reduces its incidence especially in the buccal surfaces which are bathed readily by saliva. In addition, hemoglobin and hematocrit, growth and pigmentation of the incisor teeth improve significantly with supplementation. The results of this experiment suggest that the effect of diet in the caries process involves not only the sucrose component of the diet but also an essential nutrient such as iron.

Growth, development and dental caries in rats fed two experimental diets.

In order to determine the nutritional adequacy of diets MIT 200 and NIH 2000 on the growth and development of experimental animals, these two diets were fed to two groups of animals during three periods of development: 1) pregnancy; 2) lactation, and 3) post-weaning. These diets were compared with a diet that satisfied the requirements of the National Research Council for growth and maintenance. It was found that for the two experimental diets, growth was compromised due to a caloric deficit in both diets. In addition, NIH 2000 was deficient in other nutrients such as iron. Analysis of other parameters such as hemoglobin, hematocrit, salivary protein, saliva flow and weight of vital organs upon autopsy revealed a picture of iron deficiency in the NIH 2000 group. Caries formation can be precipitated by a mechanism influenced by a nutrient deficit.

Growth, development and dental caries in rats fed two experimental diets.

Se proporcionaron las dietas MIT 200 y NIH 2000 a dos grupos de animales experimentales con el fin de determinar su adecuacion nutricional en relacion al crecimiento y desarrollo de las ratas. Estas dietas se les administraron a dos grupos de animales durante tres peridos de desarrollo: 1) prenez; 2) lactancia, y 3) post-destete.Luego se compararon con otra dieta que se ajustaba a los requerimientos para crecimiento y mantenimiento establecidos por el Consejo Nacional de Investigaciones de los Estados Unidos. Se encontro en ambos casos que debido a su deficit calorico el crecimiento era afectado por las dos dietas experimentales. Ademas, la dieta NIH 2000 era deficiente en otros nutrientes, hierro por ejemplo. El analisis de otros parametros tales como hemoglobina, hematocrito, proteina salivar, flujo salivar y peso de los organos vitales al momento de la autopsia, revelo un cuadro de deficiencia de hierro en el grupo alimentado con NIH 2000 La formacion de caries puede ser precipitada mediante un mecanismo que es influenciado por el deficit de un nutriente

Influence of supplementation on the dental caries incidence and growth of rats fed two model diets.

Con el fin de mejorar la calidad de las dietas MIT 200 y NIH 2000, ambas promotoras de caries, estas fueron suplementadas con grasa. Ademas, la dieta NIH 2000 se suplemento con minerales y vitaminas. Se encontro que la suplementacion con nutrientes esenciales mejora la calidad de ambas, y refuerza el crecimiento al compararse con el de animales testigo. Asimismo la adicion de minerales y vitaminas a la dieta NIH 2000 abolio la perdida de pigmentacion de los incisivos, mejoro la hemoglobina y el hematocrito, y redujo los puntajes de caries en las superficies bucales en 50%, en contraste con la constatada en las ratas que recibieron la dieta no suplementada. Es posible que las propiedades cariogenicas de la dieta NIH 2000 se deban en parte a la deficiencia de un nutriente dado

Influence of dietary iron on the dental caries incidence and growth of rats fed an experimental diet.

Considerando que la suplementacion con nutrientes esenciales mejora la calidad de la dieta NIH 2000 y acelera el crecimiento se llevo a cabo este estudio con el fin de determinar los efectos de la suplementacion con un nutriente especifico. Asi, la dieta 2000 fue suplementada con 35 ppm de FeSO4. administrandose luego ad libitum durante un periodo de 40 dias. Se encontro que la suplementacion con hierro revierte el proceso de la caries y reduce su incidencia, sobre todo en las superficies bucales facilmente humedecidas por la saliva Ademas, la hemoglobina y el hematocrito el crecimiento y la pigmentacion de los incisivos tambien mejora significativamente.Los resultados de este experimento sugieren que el efecto que la dieta en cuestion ejerce en el proceso de las caries, implica no solo el componente sucrosa de la dieta, sino tambien la inclusion de un nutriente esencial, tal como el hierro

Age-related immunity to measles, mumps and rubella in Middle American and United States children.

Serum samples from 3000 1 to 15-year-old children residing in the Dominican Republic, Honduras and the Republic of Panama were analyzed for measles, mumps and rubella susceptibility. These data were compared with results obtained on sera drawn from 2221 United States children of similar ages. It was found that children in all areas usually acquired immunity to measles early in life and tended to contract mumps and rubella somewhat later. Immunity data from the urban areas of the United States closely resembled that from the urban areas of the Dominican Republic. Honduran and Panamanian children showed much higher age-related frequencies of rubella, susceptibility. When compared to the other Middle American countries studied, the rural Honduran sample showed significantly higher age-grouped susceptibility rates for measles and simultaneous triple rate revealed a consistent bias, indicating that the attack rates of the three infections are not entirely independent.