Search results for " Seconda"

Activation of bee venom phospholipase A2 through a peptide-enzyme complex

1995

AbstractPhospholipase A2 activation by membrane-bound peptides was investigated in order to understand the role of the membrane-induced conformation on activation, and to examine the occurrence of a peptide-enzyme complex at the lipid/water interface. For the peptides studies, bee venom phospholipase A2 was stimulated regardless of the membrane-bound conformation (α-helix, β-sheet or random coil). Using antisera raised against melittin, we were able to demonstrate the occurrence of a calcium-dependent complex involving the enzyme, phospholipid substrate, and peptide.

Synthesis and Structure-Activity Relationships of Amino Acid Conjugates of Cholanic Acid as Antagonists of the EphA2 Receptor

2013

The Eph–ephrin system plays a critical role in tumor growth and vascular functions during carcinogenesis. We had previously identified cholanic acid as a competitive and reversible EphA2 antagonist able to disrupt EphA2-ephrinA1 interaction and to inhibit EphA2 activation in prostate cancer cells. Herein, we report the synthesis and biological evaluation of a set of cholanic acid derivatives obtained by conjugation of its carboxyl group with a panel of naturally occurring amino acids with the aim to improve EphA2 receptor inhibition. Structure-activity relationships indicate that conjugation of cholanic acid with linear amino acids of small size leads to effective EphA2 antagonists whereas …

Construction of an agglutination tool: recombinant Fab fragments biotinylated in vitro.

2009

The pComb3H vector system is used for constructing and panning recombinant antibody libraries. It allows for expression of monovalent Fab fragments, either on the surface of M13 phage, or in the form of soluble proteins secreted into the periplasmic space of bacteria. We constructed a modified pComb3H vector containing cDNA encoding for a 23-amino acid fragment of the Escherichia coli biotin carboxy carrier protein (BCCP), which is an acceptor sequence for biotinylation. The vector was used to express the Fab fragment recognizing human glycophorin A. The purified Fab fragment containing this biotin acceptor sequence was effectively biotinylated in vitro using biotin ligase (BirA). The speci…

Secondary structure of peptides. 4:13C-Nmr CP/MAS investigation of solid oligo- and poly(L-alanines)

1983

Primary and tertiary amine-initiated polymerizations of L-alanine-N-carboxyanhydride (L-Ala-NCA) were conducted at 20 or 100°C in a variety of solvents. The 75.5-MHz 13C-nmr CP/MAS spectra of the resulting poly(L-alanines) revealed that all samples contain both α-helix and pleated-sheet structures. Depending on the reaction conditions the α-helix content varied between ca. 1 and 99%. Reprecipitation from aprotic nonsolvents does not change the α-helix/β-sheet ratio, indicating that this ratio is thermodynamically controlled. Since relatively large amounts of oligopeptides of degree of polymerization (DP) 4–6 can be extracted by means of acetic acid, it is concluded that (a) most poly(L-alan…

La demande d'éducation à l'issue de l'enseignement secondaire

1978

L'enseignement secondaire inférieur en Europe : diversité et similarité des modes d'organisation

2000

International audience; Comprehensive secondary school in Europe is organized according to three types which imply different conditions of admission, different educational paths. The opportunities for taking decisions at local level concerning matters taught or students' assessment are also varying from one country to another. Though presently in Europe as a whole, a higher education level is compulsory for all teachers, teacher training takes different forms in the various European countries.

Exergy recovery in regasification facilities – Cold utilization: A modular unit

2009

Abstract The paper deals with the problem of cold recovery for direct utilization both in the site of regasification facility and far from it. A modular LNG regasification unit is proposed having the regasification capacity of 2 billion standard cubic meters/year of gas. The modular plant is based on use of a power cycle working with ethane or ethylene which allows operation of cold energy transfer, contained in LNG to be regasified, in a range of temperatures suitable for multipurpose use of cold, reducing regasification process irreversibility. Some electric energy is produced by the power cycle, but the own mission of modular unit proposed is addressed to deliver cold suitable for indust…

Variation in situation-specific engagement among lower secondary school students

2018

The majority of previous research has examined school engagement as an overall student characteristic. The present study contributes to the field by examining variation in students' situation-specific engagement from one lesson to another and by investigating situational determinants of such variation. An intensive one-week lesson-to-lesson data collection was conducted in four lower secondary school classrooms. Students rated their situation-specific engagement at the end of each lesson with a mobile-based InSitu instrument. Data comprising a total of 57 students and 1328 ratings were analyzed with two-level hierarchical multivariate model (between students, and within students between les…

Mistranslation Drives Alterations in Protein Levels and the Effects of a Synonymous Variant at the Fibroblast Growth Factor 21 Locus.

2021

This article also appears in: Health, Medical, and Life Sciences Virtual Issue for Advanced Science.

On resampling schemes for particle filters with weakly informative observations

2022

We consider particle filters with weakly informative observations (or `potentials') relative to the latent state dynamics. The particular focus of this work is on particle filters to approximate time-discretisations of continuous-time Feynman--Kac path integral models -- a scenario that naturally arises when addressing filtering and smoothing problems in continuous time -- but our findings are indicative about weakly informative settings beyond this context too. We study the performance of different resampling schemes, such as systematic resampling, SSP (Srinivasan sampling process) and stratified resampling, as the time-discretisation becomes finer and also identify their continuous-time l…