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Extremal Chemical Graphs of Maximum Degree at Most 3 for 33 Degree–Based Topological Indices
No full textpeer reviewedWe consider chemical graphs that are defined as connected graphs of maximum degree at most 3. We characterize the extremal ones, that is, those that maximize or minimize 33 degree-based topological indices. This study shows that five graph families are suf-ficient to characterize the extremal chemical graphs of 29 of these 33 indices. In other words, the extremal properties of this set of degree-based topological indices vary very little
New moonlighting activities for various GroEL/Hsp60 proteins, mainly characterized using recombinant M. tuberculosis GroEL1.
Full text linkpeer reviewedGroup I chaperonins are key proteins that control cell metabolism, stress adaptation and survival. They usually form a tetradecameric structure that assists, coupled to ATP hydrolysis, 10 % of all cellular protein folding. While working on TesA thioesterase activity, we serendipitously discovered that M. tuberculosis GroEL1 also had thioesterase activity. Using recombinant E. coli GroEL, human mitochondrial Hsp60 and GroEL1 and GroEL2 M. tuberculosis chaperonins, we found that these proteins all showed thioesterase activity. Focusing on M. tuberculosis chaperonins, we further identified that GroEL1 and GroEL2 also have esterase and auto-acyltransferase activities. The smaller oligomers of human Hsp60 and M. tuberculosis GroEL1 were able to use the long acyl carbon chain substrate palmitoyl-CoA, while tetradecameric E. coli GroEL and human Hsp60 were not. ATP, together with Mg, reduced GroEL1 dimerization, but, alone, also antagonized GroEL1 thioesterase activity. Alanine substitutions on six M. tuberculosis GroEL1 residues identified Asp86 and Thr89 in the ATP-binding pocket and an additional Ser393 as important residues for the thioesterase activity. Additionally, M. tuberculosis GroEL1 enhanced palmitoylation of the recombinant C-terminal half of the PpsE protein. As PpsE is required for phthiocerol dimycocerosate (PDIM) biosynthesis, this could explain, at least partly, the involvement of GroEL1 in M. tuberculosis PDIM biosynthesis and antibiotic resistance
Attitudes, sentiment de compétence et auto-efficacité des futurs enseignants face à la recherche en éducation
No full textPerceptions des futurs enseignants vis-à-vis de la recherche en éducation : élaboration et validation d’une sous-échelle francophone
No full textCritical points of solutions of elliptic equations in divergence form in planar non simply connected domains with smooth or nonsmooth boundary
No full textpeer reviewedWe study the critical points of the solution of second elliptic equations in divergence and diagonal form with a bounded and positive definite coefficient, under the assumption that the statement of the Hopf lemma holds (sign assumptions on its normal derivatives) along the boundary. The proof combines the argument principle introduced in [1] for elliptic equations with the representation formula (using quasi-conformal mappings) for operators in divergence form in simply connected domains [2]. The case of a degenerate coefficient is also treated where we combine the level lines technique and the maximum principle with the argument principle. Finally, some numerical experiments on illustrative examples are presented.
[1] G. Alessandrini and R. Magnanini. The index of isolated critical points and solutions of elliptic equations in the plane. Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4), 19(4):567–589, 1992.S
[2] G. Alessandrini and R. Magnanini. Elliptic equations in divergence form, geometric criticalpoints of solutions, and Stekloff eigenfunctions. SIAM J. Math. Anal., 25(5):1259–1268, 1994
Ultra-short-term heart rate variability vs. short-term heart rate variability for AF onset prediction in the era of wearables
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LLM-based Vulnerable Code Augmentation: Generate or Refactor?
No full textpeer reviewedVulnerability code-bases often suffer from severe imbalance, limiting the effectiveness of Deep Learning-based vulnerability classifiers. Data Augmentation could help solve this by mitigating the scarcity of under-represented CWEs. In this context, we investigate LLM-based augmentation for vulnerable functions, comparing controlled generation of new vulnerable samples with semantics-preserving refactoring of existing ones. Using Qwen2.5-Coder to produce augmented data and CodeBERT as a vulnerability classifier on the SVEN dataset, we find that our approaches are indeed effective in enriching vulnerable code-bases through a simple process and with reasonable quality, and that a hybrid strategy best boosts vulnerability classifiers' performance
