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1.
J Environ Manage ; 206: 1192-1203, 2018 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-29153551

RESUMEN

Land use and land cover (LULC) change has been recognized as a key driver of global climate change by influencing land surface processes. Being in constant change, river basins are always subjected to LULC changes, especially decline in forest cover to give way for agricultural expansion, urbanization, industrialization etc. We used on-screen digital interpretation technique to derive LULC maps from Landsat images at three decadal intervals i.e., 1985, 1995 and 2005 of two major river basins of India. Rain-fed, Mahanadi river basin (MRB) attributed to 55% agricultural area wherein glacier-fed, Brahmaputra river basin (BRB) had only 16% area under agricultural land. Though conversion of forest land for agricultural activities was the major LULC changes in both the basins, the rate was higher for BRB than MRB. While water body increased in MRB could be primarily attributed to creation of reservoirs and aquaculture farms; snow and ice melting attributed to creation of more water bodies in BRB. Scrub land acted as an intermediate class for forest conversion to barren land in BRB, while direct conversion of scrub land to waste land and crop land was seen in MRB. While habitation contributed primarily to LULC changes in BRB, the proximity zones around habitat and other socio-economic drivers contributed to LULC change in MRB. Comparing the predicted result with actual LULC of 2005, we obtained >97% modelling accuracy; therefore it is expected that the Dyna-CLUE model has very well predicted the LULC for the year 2025. The predicted LULC of 2025 and corresponding LULC changes in these two basins acting as early warning, and with the past 2-decadal change analysis this study is believed to help the land use planners for improved regional planning to create balanced ecosystem, especially in a changing climate.


Asunto(s)
Conservación de los Recursos Naturales , Bosques , Tecnología de Sensores Remotos , Agricultura , Monitoreo del Ambiente , India , Ríos
2.
J Nanosci Nanotechnol ; 8(12): 6266-73, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19205193

RESUMEN

This study describes about the development of a mechanical manipulation system that can perform three-dimensional nano-machining inside a scanning electron microscope (SEM). Experiments are carried out by constructing a precise machining platform integrated with pico-motors, linear stages and monolithic-silicon-based tips which is generally used in atomic-force microscope (AFM). This integrated system can easily manipulate the atoms in a workpiece inside an SEM. The platform consists of three translational stages along XYZ axis direction and one rotational stage, with a resolution of 30 nm. The system can be utilized to produce nanopattern such as nanolines, nanoscale characters on silicon substrate coated with gold (Au) and aluminum (Al). Molecular dynamics simulation model is used to analyze the machining mechanism from various machining parameters. The same AFM tip can be utilized to scratch away the unwanted material from the workpiece surface.

3.
Mol Cell Biol ; 23(14): 4739-52, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12832462

RESUMEN

Activation of the oncogenic potential of the MEK kinase TPL-2 (Cot) requires deletion of its C terminus. This mutation also weakens the interaction of TPL-2 with NF-kappaB1 p105 in vitro, although it is unclear whether this is important for the activation of TPL-2 oncogenicity. It is demonstrated here that TPL-2 stability in vivo relies on its high-affinity, stoichiometric association with NF-kappaB1 p105. Formation of this complex occurs as a result of two distinct interactions. The TPL-2 C terminus binds to a region encompassing residues 497 to 534 of p105, whereas the TPL-2 kinase domain interacts with the p105 death domain. Binding to the p105 death domain inhibits TPL-2 MEK kinase activity in vitro, and this inhibition is significantly augmented by concomitant interaction of the TPL-2 C terminus with p105. In cotransfected cells, both interactions are required for inhibition of TPL-2 MEK kinase activity and, consequently, the catalytic activity of a C-terminally truncated oncogenic mutant of TPL-2 is not affected by p105. Thus, in addition to its role as a precursor for p50 and cytoplasmic inhibitor of NF-kappaB, p105 is a negative regulator of TPL-2. Insensitivity of C-terminally truncated TPL-2 to this regulatory mechanism is likely to contribute to its ability to transform cells.


Asunto(s)
Quinasas Quinasa Quinasa PAM/metabolismo , FN-kappa B/metabolismo , Precursores de Proteínas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Células 3T3 , Animales , Sitios de Unión , Estabilidad de Enzimas , MAP Quinasa Quinasa 1 , Quinasas Quinasa Quinasa PAM/genética , Ratones , Quinasas de Proteína Quinasa Activadas por Mitógenos/genética , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , FN-kappa B/genética , Subunidad p50 de NF-kappa B , Fragmentos de Péptidos/metabolismo , Unión Proteica , Precursores de Proteínas/genética , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Estructura Terciaria de Proteína , Proteínas Proto-Oncogénicas/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
4.
Oncogene ; 18(41): 5654-61, 1999 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-10523845

RESUMEN

The tumor suppressor protein APC (Adenomatous Polyposis Coli) is localized in the cytosol and in the nucleus. In this study, we demonstrate that the nuclear APC protein level is high in cells in the basal crypt region of the normal colorectal epithelium. Strikingly, the APC protein staining resembles the staining pattern of a nuclear proliferation marker. As a first step towards a possible role of the nuclear APC protein, we provide data showing the direct interaction of the nuclear APC protein with DNA. A nuclear APC isoform precipitates with matrix-immobilized DNA. Vice versa, the immunoprecipitation of APC from nuclear lysates results in co-precipitation of genomic DNA. Using recombinant APC fragments we mapped three DNA binding domains: one within the beta-catenin binding and regulatory domain, and two in the carboxyterminal third of the APC protein. All these three domains contain clusters of repetitive S(T)PXX sequence motifs that were described to mediate the DNA interaction of many other DNA binding proteins. In analogy to S(T)PXX proteins, the APC protein binds preferentially to A/T rich DNA sequences rather than to a single DNA sequence motif.


Asunto(s)
Emparejamiento Base , Proteínas del Citoesqueleto/metabolismo , ADN/metabolismo , Genes APC , Poliposis Adenomatosa del Colon/metabolismo , Proteína de la Poliposis Adenomatosa del Colon , Unión Competitiva , Bisbenzimidazol/metabolismo , Núcleo Celular/metabolismo , Proteínas del Citoesqueleto/química , Humanos , Fragmentos de Péptidos/metabolismo , Unión Proteica , Conformación Proteica , Isoformas de Proteínas/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Células Tumorales Cultivadas
5.
J Chromatogr A ; 722(1-2): 353-7, 1996 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-9019304

RESUMEN

A micellar electrokinetic capillary chromatographic (MECC) method has been developed and optimised for the separation of 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG). The running buffer consisted of a mixture of 20 mM sodium phosphate and 20 mM sodium borate containing 50 mM sodium dodecyl sulphate (SDS) adjusted to pH 9.5 with 1 M NaOH. The running voltage and temperature were 20-25 kV and 30 degrees C, respectively. The MECC method for the analysis of PBG is fast and simple and is useful for the screening of PBG in the urine of patients suspected to have acute intermittent porphyria (AIP), and for the confirmation of lead exposure by measuring red-cell ALA-dehydratase (ALA-D) activity with ALA as the enzyme substrate.


Asunto(s)
Eritrocitos/enzimología , Porfobilinógeno Sintasa/sangre , Porfobilinógeno/orina , Ácido Aminolevulínico/metabolismo , Electroforesis Capilar , Humanos , Concentración de Iones de Hidrógeno , Intoxicación por Plomo/sangre , Intoxicación por Plomo/enzimología , Micelas , Porfiria Intermitente Aguda/orina , Espectrofotometría Ultravioleta
6.
Nanotechnology ; 19(2): 025710, 2008 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-21817559

RESUMEN

In this investigation titanate nanowires were synthesized by a microwave hydrothermal process and their nanomechanical characterization was carried out by a compression experiment via buckling instability using a nanomanipulator inside a scanning electron microscope. Nanowires of diameters 120-150 nm and length tens of microns can be synthesized by keeping a commercial nanoparticle inside a microwave oven at 350 W and 210 °C for 5 h. The nanowire was clamped between two cantilevered AFM tips attached to two opposing stages of the manipulator for nanomechanical characterization. The elasticity coefficients of the titanate nanowires were measured by applying a continuously increasing load and observing the buckling instability of the nanowires. The buckling behavior of a nanowire was analyzed from the series of SEM images of displacement of the cantilever attached to the nanowire due to application of load. The critical loads for different sized titanate nanowires were determined and their corresponding Young's modulus was computed with the Euler pinned-fixed end model. The Young's modulus of these microwave hydrothermal process synthesized titanate nanowires were determined to be approximately in the range 14-17 GPa. This investigation confirms the capability of the nanomanipulator via the buckling technique as a constructive device for measuring the mechanical properties of nanoscale materials.

7.
Eur J Biochem ; 253(3): 591-7, 1998 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-9654054

RESUMEN

The tumor-suppressor protein APC (adenomatous polyposis coli) binds to microtubules and promotes tubulin assembly. In vivo the endogenous APC protein is mainly localized at the end of microtubules that are involved in active cell migration. Since most tumor-specific APC gene mutations lead to the loss of the microtubule binding domain this interaction is assumed to play a crucial role in tumorigenesis. In this study we show that an APC protein fragment (amino acids 2219-2580) within the C-terminal part is enough to bind to non-assembled tubulin with high affinity. The binding of APC to tubulin does not lead to an alteration of the intrinsic GTPase activity of the non-assembled tubulin. The APC protein induces the tubulin assembly in a fast reaction and below the critical assembly concentration of tubulin. The APC protein induces the bundling of the assembled microtubules in a concentration-dependent manner. Regarding its biochemical properties the analysed APC protein fragment strikingly resembles the members of the microtubule-associated protein family tau. This analogy may help to understand the role of the APC protein in the suppression of tumorigenesis.


Asunto(s)
Proteínas del Citoesqueleto/química , Conformación Proteica , Proteínas tau/química , Proteína de la Poliposis Adenomatosa del Colon , Secuencia de Aminoácidos , Animales , Sitios de Unión , Bovinos , Dicroismo Circular , Clonación Molecular , Proteínas del Citoesqueleto/metabolismo , Dimerización , GTP Fosfohidrolasas/metabolismo , Genes APC , Humanos , Cinética , Microtúbulos/ultraestructura , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo
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