scispace - formally typeset
Search or ask a question
Institution

National Autonomous University of Mexico

EducationMexico City, Distrito Federal, Mexico
About: National Autonomous University of Mexico is a education organization based out in Mexico City, Distrito Federal, Mexico. It is known for research contribution in the topics: Population & Galaxy. The organization has 72868 authors who have published 127797 publications receiving 2285543 citations. The organization is also known as: UNAM & Universidad Nacional Autónoma de México.


Papers
More filters
Journal ArticleDOI
TL;DR: In an ecological survey of nitrogen-fixing bacteria isolated from the rhizosphere and as endophytes of sugarcane, maize and teosinte plants in Brazil, Mexico and South Africa, a new phylogenetically homogeneous group of N(2)- fixing bacteria was identified within the genus Burkholderia.
Abstract: In an ecological survey of nitrogen-fixing bacteria isolated from the rhizosphere and as endophytes of sugarcane, maize and teosinte plants in Brazil, Mexico and South Africa, a new phylogenetically homogeneous group of N(2)-fixing bacteria was identified within the genus Burkholderia. This polyphasic taxonomic study included microscopic and colony morphology, API 20NE tests and growth on different culture media at different pH and temperatures, as well as carbon source assimilation tests and whole-cell protein pattern analysis. Analysis of 16S rRNA gene sequences showed 99.2-99.9 % similarity within the novel species and 97.2 % similarity to the closest related species, Burkholderia sacchari. The novel species was composed of four distinct amplified 16S rDNA restriction analysis groups. The DNA-DNA reassociation values within the novel species were greater than 70 % and less than 42 % for the closest related species, B. sacchari. Based on these results and on many phenotypic characteristics, a novel N(2)-fixing species is proposed for the genus Burkholderia, Burkholderia tropica sp. nov., with the type strain Ppe8(T) (=ATCC BAA-831(T)=LMG 22274(T)=DSM 15359(T)). B. tropica was isolated from plants grown in geographical regions with climates ranging from temperate subhumid to hot humid.

264 citations

Journal ArticleDOI
TL;DR: An algebraic framework for the description of baryons is introduced and a collective string-like model is studied, which gives a good overall description of the presently available data, in particular masses and electromagnetic couplings.

263 citations

Journal ArticleDOI
TL;DR: The benefits of garlic to health have been proclaimed for centuries; however, only recently have Allium sativum and its derivatives been proposed as promising candidates for maintaining the homeostasis of the immune system as discussed by the authors.
Abstract: The benefits of garlic to health have been proclaimed for centuries; however, only recently have Allium sativum and its derivatives been proposed as promising candidates for maintaining the homeostasis of the immune system. The complex biochemistry of garlic makes it possible for variations in processing to yield different preparations with differences in final composition and compound proportion. In this review, we assess the most recent experimental results, which indicate that garlic appears to enhance the functioning of the immune system by stimulating certain cell types, such as macrophages, lymphocytes, natural killer (NK) cells, dendritic cells, and eosinophils, by mechanisms including modulation of cytokine secretion, immunoglobulin production, phagocytosis, and macrophage activation. Finally, because immune dysfunction plays an important role in the development and progress of several diseases, we critically examined immunoregulation by garlic extracts and compounds isolated, which can contribute to the treatment and prevention of pathologies such as obesity, metabolic syndrome, cardiovascular disorders, gastric ulcer, and even cancer. We concluded that A. sativum modulates cytokine secretion and that such modulation may provide a mechanism of action for many of their therapeutic effects.

263 citations

Journal ArticleDOI
TL;DR: In this article, the identification of pyromorphite in phosphate amended soils has been carried out by different non destructive techniques such as X-ray diffraction, scanning electron microscopy coupled with energy dispersive Xray spectroscopy, Xray absorption fine structure and electron microprobe analysis, the effectiveness of in situ Pb immobilization has also been evaluated by selective sequential extraction, by toxicity leaching procedure and by a physiologically based extraction procedure simulating metal ingestion and gastrointestinal bioavailability to humans.
Abstract: In its soluble ionic forms, lead (Pb) is a toxic element occurring in waters and soils mainly as the result of human activities. The bioavailability of lead ions can be decreased by complexation with various materials in order to decrease their toxicity. Pb chemical immobilization using phosphate addition is a widely accepted technique to immobilize Pb from aqueous solution and contaminated soils. The application of different P amendments cause Pb in soils to shift from forms with high availability to the most strongly bound Pb fractions. The increase of Pb in the residual or insoluble fraction results from formation of pyromorphite Pb5(PO4)3X where X = F, Cl, Br, OH, the most stable environmental Pb compounds under a wide range of pH and Eh natural conditions. Accidental pyromorphite ingestion does not yield bioavailable lead, because pyromorphite is insoluble in the intestinal tract. Numerous natural and synthetic phosphates materials have been used to immobilize Pb: apatite and hydroxyapatite, biological apatite, rock phosphate, soluble phosphate fertilizers such as monoammonium phosphate, diammonium phosphate, phosphoric acid, biosolids rich in P, phosphatic clay and mixtures. The identification of pyromorphite in phosphate amended soils has been carried out by different non destructive techniques such as X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, X-ray absorption fine structure, transmission electron microscopy and electron microprobe analysis. The effectiveness of in situ Pb immobilization has also been evaluated by selective sequential extraction, by the toxicity leaching procedure and by a physiologically based extraction procedure simulating metal ingestion and gastrointestinal bioavailability to humans. Efficient Pb immobilization using P amendments requires increasing the solubility of the phosphate phase and of the Pb species phase by inducing acid conditions. Although phosphorus addition seems to be highly effective, excess P in soil and its potential effect on eutrophication of surface water, and the possibility of As enhanced leaching remains a concern. The use of mixed treatments may be a useful strategy to improve their effectiveness in reducing lead phyto- and bioavailability.

263 citations

Journal ArticleDOI
TL;DR: In this paper, the formation of organic molecules in space has been studied and the physical and chemical conditions, including density, temperature, ultraviolet (UV) radiation and energetic particles, have been used to determine reaction pathways and the complexity of organic molecule in different space environments.
Abstract: Stellar nucleosynthesis of heavy elements such as carbon allowed the formation of organic molecules in space, which appear to be widespread in our Galaxy. The physical and chemical conditions—including density, temperature, ultraviolet (UV) radiation and energetic particles—determine reaction pathways and the complexity of organic molecules in different space environments. Dense interstellar clouds are the birth sites of stars of all masses and their planetary systems. During the protostellar collapse, interstellar organic molecules in gaseous and solid phases are integrated into protostellar disks from which planets and smaller solar

263 citations


Authors

Showing all 73617 results

NameH-indexPapersCitations
Richard Peto183683231434
Anton M. Koekemoer1681127106796
Rory Collins162489193407
Timothy C. Beers156934102581
Vivek Sharma1503030136228
Kjell Fuxe142147989846
Prashant V. Kamat14072579259
Carmen García139150396925
Harold A. Mooney135450100404
Efe Yazgan12898679041
Roberto Maiolino12781661724
Peter Nugent12775492988
William R. Miller12560172570
Nicholas A. Kotov12357455210
John C. Wingfield12250952291
Network Information
Related Institutions (5)
Complutense University of Madrid
90.2K papers, 2.1M citations

90% related

Spanish National Research Council
220.4K papers, 7.6M citations

90% related

Autonomous University of Madrid
52.8K papers, 1.6M citations

89% related

University of Granada
59.2K papers, 1.4M citations

89% related

University of Buenos Aires
50.9K papers, 1M citations

89% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20241
2023311
2022967
20217,481
20207,906
20197,107