19 research outputs found
Experience from Two Resistivity Inversion Techniques Applied in Three Cases of Geotechnical Site Investigation
Seismic Characterisation of a Site in the Alps
This study concerns the dynamic characterisation devoted to seismic response analysis of an Alpine test site.
We show how integration and combination of different seismic techniques allow a comprehensive characterisation of the site leading to a reliable 2D model for site amplification studies. For the evaluation of the deep structure and the location of the seismic bedrock, combined seismic reflection-refraction tests are used while the shear wave velocity profile is obtained by down-hole measurements and surface wave tests, performed integrating passive and active data to increase the depth of penetration without loosing in resolution of shallow layers. The ground roll affecting reflection-refraction seismic data is also used to reconstruct lateral variation of the shear wave velocity in the soil deposit by means of an innovative
inversion approach based on the integration of Monte Carlo and Laterally Constrained Inversion, in which the Vs profiles obtained from the others seismic techniques are used as constrains to improve the reliability of the final solution. Moreover an estimation of the quality factor (Q) is performed from records acquired for surface wave analysis.
The use of the same seismic records for different and independent analysis optimize the cost effectiveness of the whole survey
Laterally constrained inversion of ground roll of seismic reflection records
A new strategy for processing and inverting surface waves retrieved by seismic reflection ground roll is presented. The
use of a Laterally Constrained Inversion algorithm allows for estimating a reliable subsoil model also in the case of smooth lateral variations in spite of the 1D approach used for surface wave interpretation. A Montecarlo analysis is also performed for model assessment. An experimental case is used to discuss advantages and limits of the proposed approach
Long-Term Green Tea Extract Supplementation Does Not Affect Fat Absorption, Resting Energy Expenditure, and Body Composition in Adults
BACKGROUND: Green tea (GT) extract may play a role in body weight regulation. Suggested mechanisms are decreased fat absorption and increased energy expenditure. OBJECTIVE: We examined whether GT supplementation for 12 wk has beneficial effects on weight control via a reduction in dietary lipid absorption as well as an increase in resting energy expenditure (REE). METHODS: Sixty Caucasian men and women [BMI (in kg/m2): 18-25 or >25; age: 18-50 y] were included in a randomized placebo-controlled design in which fecal energy content (FEC), fecal fat content (FFC), resting energy expenditure, respiratory quotient (RQ), body composition, and physical activity were measured twice (baseline vs. week 12). For 12 wk, subjects consumed either GT (>0.56 g/d epigallocatechin gallate + 0.28-0.45 g/d caffeine) or placebo capsules. Before the measurements, subjects recorded energy intake for 4 consecutive days and collected feces for 3 consecutive days. RESULTS: No significant differences between groups and no significant changes over time were observed for the measured variables. Overall means +/- SDs were 7.2 +/- 3.8 g/d, 6.1 +/- 1.2 MJ/d, 67.3 +/- 14.3 kg, and 29.8 +/- 8.6% for FFC, REE, body weight, and body fat percentage, respectively.Conclusion: GT supplementation for 12 wk in 60 men and women did not have a significant effect on FEC, FFC, REE, RQ, and body composition. This trial was registered at clinicaltrials.gov as NCT01556321
Identification of Key Hinge Residues Important for Nucleotide-Dependent Allostery in E. coli Hsp70/DnaK
Equilibration of labelled and endogenous bile acids in patients with liver cirrhosis after administration of (24- 14
Cochaperones enable Hsp70 to use ATP energy to stabilize native proteins out of the folding equilibrium
Pharmacological Tuning of Heat Shock Protein 70 Modulates Polyglutamine Toxicity and Aggregation
Nine neurodegenerative disorders are caused by the abnormal expansion of polyglutamine (polyQ) regions within distinct proteins. Genetic and biochemical evidence has documented that the molecular chaperone, heat shock protein 70 (Hsp70), modulates polyQ toxicity and aggregation, yet it remains unclear how Hsp70 might be used as a potential target in polyQ-related diseases. We have utilized a pair of membrane-permeable compounds that tune the activity of Hsp70 by either stimulating or by inhibiting its ATPase functions. Using these two pharmacological agents in both yeast and PC12 cell models of polyQ aggregation and toxicity, we were surprised to find that stimulating Hsp70 solubilized polyQ conformers and simultaneously exacerbated polyQ-mediated toxicity. By contrast, inhibiting Hsp70’s ATPase activity protected against polyQ toxicity and promoted aggregation. These findings clarify Hsp70’s role as a possible drug target in polyQ disorders and suggest that Hsp70 uses ATP hydrolysis to help partition polyQ proteins into structures with varying levels of proteotoxicity. Our results thus support an emerging concept in which certain kinds of polyQ aggregates may be protective, while more soluble polyQ species are toxic
Plasmodium falciparum encodes a single cytosolic type I Hsp40 that functionally interacts with Hsp70 and is upregulated by heat shock
Heat shock protein 70 (Hsp70) and heat shock protein 40 (Hsp40) function as molecular chaperones during the folding and trafficking of proteins within most cell types. However, the Hsp70–Hsp40 chaperone partnerships within the malaria parasite, Plasmodium falciparum, have not been elucidated. Only one of the 43 P. falciparum Hsp40s is predicted to be a cytosolic, canonical Hsp40 (termed PfHsp40) capable of interacting with the major cytosolic P. falciparum-encoded Hsp70, PfHsp70. Consistent with this hypothesis, we found that PfHsp40 is upregulated under heat shock conditions in a similar pattern to PfHsp70. In addition, PfHsp70 and PfHsp40 reside mainly in the parasite cytosol, as assessed using indirect immunofluorescence microscopy. Recombinant PfHsp40 stimulated the ATP hydrolytic rates of both PfHsp70 and human Hsp70 similar to other canonical Hsp40s of yeast (Ydj1) and human (Hdj2) origin. In contrast, the Hsp40-stimulated plasmodial and human Hsp70 ATPase activities were differentially inhibited in the presence of pyrimidinone-based small molecule modulators. To further probe the chaperone properties of PfHsp40, protein aggregation suppression assays were conducted. PfHsp40 alone suppressed protein aggregation, and cooperated with PfHsp70 to suppress aggregation. Together, these data represent the first cellular and biochemical evidence for a PfHsp70–PfHsp40 partnership in the malaria parasite, and furthermore that the plasmodial and human Hsp70–Hsp40 chaperones possess unique attributes that are differentially modulated by small molecules