403 research outputs found
The polarized expression of Na+,K+-ATPase in epithelia depends on the association between beta-subunits located in neighboring cells
The polarized distribution of Na+,K+-ATPase plays a paramount physiological role, because either directly or through coupling with co- and countertransporters, it is responsible for the net movement of, for example, glucose, amino acids, Ca2+, K+, Cl-, and CO3H- across the whole epithelium. We report here that the beta-subunit is a key factor in the polarized distribution of this enzyme. 1) Madin-Darby canine kidney (MDCK) cells (epithelial from dog kidney) express the Na+,K+-ATPase over the lateral side, but not on the basal and apical domains, as if the contact with a neighboring cell were crucial for the specific membrane location of this enzyme. 2) MDCK cells cocultured with other epithelial types (derived from human, cat, dog, pig, monkey, rabbit, mouse, hamster, and rat) express the enzyme in all (100%) homotypic MDCK/MDCK borders but rarely in heterotypic ones. 3) Although MDCK cells never express Na+,K+-ATPase at contacts with Chinese hamster ovary (CHO) cells, they do when CHO cells are transfected with beta(1)-subunit from the dog kidney (CHO-beta). 4) This may be attributed to the adhesive property of the beta(1)-subunit, because an aggregation assay using CHO (mock-transfected) and CHO-beta cells shows that the expression of dog beta(1)-subunit in the plasma membrane does increase adhesiveness. 5) This adhesiveness does not involve adherens or tight junctions. 6) Transfection of beta(1)-subunit forces CHO-beta cells to coexpress endogenous a-subunit. Together, our results indicate that MDCK cells express Na+,K+-ATPase at a given border provided the contacting cell expresses the dog P,-subunit. The cell-cell interaction thus established would suffice to account for the polarized expression and positioning of Na+,K+-ATPase in epithelial cells
Do elephants feel pain and if so, how do we know this?
The objective of this document is to identify the behavior of the academic international production in urban history, from the bibliographical records index-linked in Scopus between 1973 and 2010. We use bibliometric indicators from SCImago Group, applying them to the production in the field of arts and humanities. Afterward, we corroborate the results obtained with the indicators calculated exclusively for 1.098 records of urban history. A geographical concentration is observed in the mechanisms of diffusion, authors and institutional affiliation. Likewise, we identify that over 50% of the works published between 1973 and 2010 have not been used by other authors to create new knowledge.El propósito de este documento es identificar el comportamiento de la producción académica internacional en historia urbana, a partir de los registros bibliográficos indizados en Scopus entre 1973 y 2010. Para ello se emplean indicadores bibliométricos obtenidos de SCImago Group y aplicados a la producción en el área de artes y humanidades. Posteriormente, se contrastan los resultados obtenidos con los indicadores calculados exclusivamente para 1.098 registros de historia urbana. Se evidencia una concentración geográfica en los medios de difusión de los productos del área, los autores y su filiación. Se identifica también que más del 50% de los trabajos realizados entre 1973 y 2010 no ha sido empleado por otro autor para crear nuevo conocimientoO propósito deste documento é identificar o comportamento da produção acadêmica internacional em história urbana, a partir dos registros bibliográficos indexados em Scopus entre 1973 e 2010. Para isso, empregam-se indicadores bibliométricos obtidos de SCImago Group e aplicados à produção na área de artes e humanidades. Posteriormente, se contrastam os resultados obtidos com os indicadores calculados exclusivamente para 1,098 registros de historia urbana. Evidencia-se uma concentração geográfica nos meios de difusão dos produtos da área, os autores e sua filiação. Identifica-se também que mais do 50% dos trabalhos realizados entre 1973 e 2010 não tem sido empregados por outro autor para criar conhecimento novo
The Shelton Mastodon Site: Multidisciplinary Study of a Late Pleistocene (Twocreekan) Locality in Southeastern Michigan
393-436http://deepblue.lib.umich.edu/bitstream/2027.42/48536/2/ID389.pd
The Elephants of Gash-Barka, Eritrea: Nuclear and Mitochondrial Genetic Patterns
Eritrea has one of the northernmost populations of African elephants. Only about 100 elephants persist in the Gash-Barka administrative zone. Elephants in Eritrea have become completely isolated, with no gene flow from other elephant populations. The conservation of Eritrean elephants would benefit from an understanding of their genetic affinities to elephants elsewhere on the continent and the degree to which genetic variation persists in the population. Using dung samples from Eritrean elephants, we examined 18 species-diagnostic single nucleotide polymorphisms in 3 nuclear genes, sequences of mitochondrial HVR1 and ND5, and genotyped 11 microsatellite loci. The sampled Eritrean elephants carried nuclear and mitochondrial DNA markers establishing them as savanna elephants, with closer genetic affinity to Eastern than to North Central savanna elephant populations, and contrary to speculation by some scholars that forest elephants were found in Eritrea. Mitochondrial DNA diversity was relatively low, with 2 haplotypes unique to Eritrea predominating. Microsatellite genotypes could only be determined for a small number of elephants but suggested that the population suffers from low genetic diversity. Conservation efforts should aim to protect Eritrean elephants and their habitat in the short run, with restoration of habitat connectivity and genetic diversity as long-term goals.https://digitalcommons.snc.edu/faculty_staff_works/1030/thumbnail.jp
Toward a first-principles integrated simulation of tokamak edge plasmas
Performance of the ITER is anticipated to be highly sensitive to the edge plasma condition. The edge pedestal in ITER needs to be predicted from an integrated simulation of the necessary first-principles, multi-scale physics codes. The mission of the SciDAC Fusion Simulation Project (FSP) Prototype Center for Plasma Edge Simulation (CPES) is to deliver such a code integration framework by (1) building new kinetic codes XGC0 and XGC1, which can simulate the edge pedestal buildup; (2) using and improving the existing MHD codes ELITE, M3D-OMP, M3D-MPP and NIMROD, for study of large-scale edge instabilities called Edge Localized Modes (ELMs); and (3) integrating the codes into a framework using cutting-edge computer science technology. Collaborative effort among physics, computer science, and applied mathematics within CPES has created the first working version of the End-to-end Framework for Fusion Integrated Simulation (EFFIS), which can be used to study the pedestal-ELM cycles
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