Search results for "PCA"

A Population-Based 3D Atlas of the Pathological Lumbar Spine Segment

2022

The spine is the load-bearing structure of human beings and may present several disorders, with low back pain the most frequent problem during human life. Signs of a spine disorder or disease vary depending on the location and type of the spine condition. Therefore, we aim to develop a probabilistic atlas of the lumbar spine segment using statistical shape modeling (SSM) and then explore the variability of spine geometry using principal component analysis (PCA). Using computed tomography (CT), the human spine was reconstructed for 24 patients with spine disorders and then the mean shape was deformed upon specific boundaries (e.g., by ±3 or ±1.5 standard deviation). Results dem…

Bromodomain factor 1 (Bdf1) protein interacts with histones

2001

AbstractUsing a yeast two-hybrid assay we detected an interaction between the N-terminal region of histone H4 (amino acids 1–59) and a fragment of the bromodomain factor 1 protein (Bdf1p) (amino acids 304–571) that includes one of the two bromodomains of this protein. No interaction was observed using fragments of histone H4 sequence smaller than the first 59 amino acids. Recombinant Bdf1p (rBdf1p) demonstrates binding affinity for histones H4 and H3 but not H2A and H2B in vitro. Moreover, rBdf1p is able to bind histones H3 and H4 having different degrees of acetylation. Finally, we have not detected histone acetyltransferase activity associated with Bdf1p.

PCAF catalyzes tha acetylation of spermidine to N8-acetylspermidine and regulates its acetylating activity on histones

2011

Post-transcriptional histone acetylation is a well known process playing a crucial role in chromatin assembly and transcription. Here, we report that PCAF, a highly conserved histone acetyltransferase (HAT), can efficiently catalyze acetylation of spermidine to N8-acetylspermidine, at low concentration. Remarkably, we found that spermidine at higher concentration can also inhibit PCAF HAT activity directed against histone H3 in vitro, confirming the in vivo data referred by Eisenberg et al. on the spermidine induced inhibition of H3 acetylation. Surprisingly when we performed HAT assay experiments at low spermidine concentration we observed an activating effect on PCAF on H3 acetylation. Ou…

A gallery of Chua's Attractors - Part V

2007

Enhancement of lysine acetylation accelerates wound repair

2013

In physiopathological conditions, such as diabetes, wound healing is significantly compromised and chronic complications, including ulcers, may occur. In a mouse model of skin repair, we recently reported that wound treatment with Sirtuin activators and class I HDAC inhibitors induced keratinocyte proliferation and enhanced healing via a nitric oxide (NO) dependent mechanism. We observed an increase in total protein acetylation in the wound area, as determined by acetylation of α-tubulin and histone H3 Lysine 9. We reasoned that this process activated cell function as well as regulated gene expression to foster tissue repair. We report here that the direct activation of P300/CBP-associated …

Regulation of PCAF Activity by Spermidine

2011

Histones and polyamines are important determinants of chromatin structure. Histones are the core of nucleosome particles and their modification by acetylation of N-terminal tails is involved in chromatin structural changes and transcriptional modulation. Polyamines also, including spermidine, are targets of both nuclear and cytoplasmic acetylation, which in turn alters their affinity for DNA and nucleosomes. Previous studies report an interplay existing between polyamines metabolism and levels, and histone acetylation. The relationship between polyamines and histone epigenetics in vivo has been considered in various models of ageing through epigenetic modifications, induction of autophagy a…

Functional Principal Component Analysis for the explorative analysis of multisite-multivariate air pollution time series with long gaps

2013

The knowledge of the urban air quality represents the first step to face air pollution issues. For the last decades many cities can rely on a network of monitoring stations recording concentration values for the main pollutants. This paper focuses on functional principal component analysis (FPCA) to investigate multiple pollutant datasets measured over time at multiple sites within a given urban area. Our purpose is to extend what has been proposed in the literature to data that are multisite and multivariate at the same time. The approach results to be effective to highlight some relevant statistical features of the time series, giving the opportunity to identify significant pollutants and…

A Data-Driven Approach for Studying the Influence of Carbides on Work Hardening of Steel

2022

This study proposes a new approach to determine phenomenological or physical relations between microstructure features and the mechanical behavior of metals bridging advanced statistics and materials science in a study of the effect of hard precipitates on the hardening of metal alloys. Synthetic microstructures were created using multi-level Voronoi diagrams in order to control microstructure variability and then were used as samples for virtual tensile tests in a full-field crystal plasticity solver. A data-driven model based on Functional Principal Component Analysis (FPCA) was confronted with the classical Voce law for the description of uniaxial tensile curves of synthetic AISI 420 ste…

Soil chemical and biochemical properties of a salt-marsh alluvial Spanish area after long-term reclamation

2009

Marisma, one of the largest salt-marsh alluvial areas in SW Spain, has been reclaimed since 1970 by artificial drainage and amendment with phosphogypsum (PG) so as to reduce Na+ saturation. Within the reclaimed area, two 250- × 20-m plots were treated as follows: (1) amendment with 25 Mg/ha of PG every 2 to 3 years between 1979 and 2003 (plot PY); (2) like PY but PG treatment stopped after 1997 (plot DR). A contiguous virgin Marisma salt-marsh plot (MV), neither drained nor amended, was the control. In MV, soil microbial biomass C, most enzyme activities and total organic C content were much greater than in PY and DR soils, despite the salinity stress. The decrease in soil organic matter co…

LA QUALITÉ ET LA VALEUR PERÇUE DANS LE TRANSPORT DE MARCHANDISES EN ESPAGNE ET LEUR IMPORTANCE DANS LA SEGMENTATION DE LA CLIENTÈLE

2015

En el estudio académico de las actividades logísticas y específicamente del transporte de mercancías, se ha señalado la influencia de la calidad del servicio en la generación y percepción de valor, así como la importancia de estos dos constructos en el proceso de evaluación del servicio en este entorno particular. En este trabajo se pretende identificar y caracterizar segmentos de empresas que prestan servicios de gestión del transporte internacional de mercancías (transitarias), con base en el valor que perciben del servicio recibido de sus principales proveedores de transporte de mercancías. A través de la realización de un análisis factorial exploratorio sobre una muestra de 205 empresas…