[Kirja-arvostelu]

Kirjallisuusarvostelu

Intrinsically bent DNA sites in the Drosophila melanogaster third chromosome amplified domain

Bent DNA sites promote the curvature of DNA in both eukaryotic and prokaryotic chromosomes. Here, we investigate the localization and structure of intrinsically bent DNA sites in the extensively characterized Drosophila melanogaster third chromosome DAFC-66D segment (Drosophila amplicon in the follicle cells). This region contains the amplification control element ACE3, which is a replication enhancer that acts in cis to activate the major replication origin ori-beta. Through both electrophoretic and in silico analysis, we have identified three major bent DNA sites in DAFC-66D. The bent DNA site (b1) is localized in the ACE3 element, whereas the other two bent DNA sites (b2 and b3) are localized in the ori-beta region. Four additional bent DNA sites were identified in the intron of the S18 gene and near the TATA box of the S15, S19, and S16 genes. The identification of DNA bent sites in genomic regions previously characterized as functionally relevant for DNA amplification further supports a function for DNA bent sites in DNA replication in eukaryotes.

Strength improvement of adhesively-bonded joints using a reverse-bent geometry

Adhesive bonding of components has become more efficient in recent years due to the developments in adhesive technology, which has resulted in higher peel and shear strengths, and also in allowable ductility up to failure. As a result, fastening and riveting methods are being progressively replaced by adhesive bonding, allowing a big step towards stronger and lighter unions. However, single-lap bonded joints still generate substantial peel and shear stress concentrations at the overlap edges that can be harmful to the structure, especially when using brittle adhesives that do not allow plasticization in these regions. In this work, a numerical and experimental study is performed to evaluate the feasibility of bending the adherends at the ends of the overlap for the strength improvement of single-lap aluminium joints bonded with a brittle and a ductile adhesive. Different combinations of joint eccentricity were tested, including absence of eccentricity, allowing the optimization of the joint. A Finite Element stress and failure analysis in ABAQUS® was also carried out to provide a better understanding of the bent configuration. Results showed a major advantage of using the proposed modification for the brittle adhesive, but the joints with the ductile adhesive were not much affected by the bending technique.

equivalence of almost bent and almost perfect nonlinear functions and their generalizations

Vectorial Boolean function, almost bent, almost perfect nonlinear, affine equivalence, CCZ-equivalence

Haita Shelt Naro Beloukid ; Ana Bent Darna Gharni Baddad / Cheikha El Oualida, El Koreha et Khadouj Bent El Maachia, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Haitama Bine Djmaa Oultlata ; Haita Ellah Ydaoui El Hal / Cheikha El Oualida, El Koreha et Khadouj Bent El Maachia, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Haita Hala Sidi Beliout ; Haita Sidi Lahsen Laidi / Cheikha Aicha Bent Loukid et Cheikha Khadouj Bent El Kebir, duo voc. [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Nouvelle Haita de Chaouia ; Haita Hadak Ya Sidi / Cheikha Aicha Bent Loukid et Cheikha Khadouj Bent El Kebir, duo voc. [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Haita Beidaouia ; Haita Slaouia / Cheikha Aicha Bent Loukid et Cheikha Khadouj Bent El Kebir, duo voc. [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Haita Zdida Dialt Salé ; Haita Erbatia / Cheikha Aicha Bent Loukid et Cheikha Khadouj Bent El Kebir, duo voc. [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

A regra de Bent contextualiza a força da ligação de hidrogênio em clusters trimoleculares

This article presents a theoretical study of the molecular properties of trimolecular clusters of CnHm∙∙∙HCN∙∙∙HX formed by the ϖ∙∙∙H and n∙∙∙H hydrogen bonds. The interaction strengths of these interactions are in line with the variations in s-character, and independently, the red-shift rise whether stronger or weaker bound systems are carried out. This behavior was justified via NBO analysis and supported by Bent´s rule, wherein the greater variations in s-character of X are in good agreement with larger red-shifts and vice-versa. To conclude, the refinement of the supermolecule approach and NBO binding energies also corroborate in this regard.

Intrinsic bent DNA sites in the chromosomal replication origin of Xylella fastidiosa 9a5c

The features of the nucleotide sequences in both replication and promoter regions have been investigated in many organisms. Intrinsically bent DNA sites associated with transcription have been described in several prokaryotic organisms. The aim of the present study was to investigate intrinsic bent DNA sites in the segment that holds the chromosomal replication origin, oriC, of Xylella fastidiosa 9a5c. Electrophoretic behavior analyses, as well as in silico analyses of both the 2-D projection and helical parameters, were performed. The chromosomal segment analyzed contains the initial sequence of the rpmH gene, an intergenic region, the dnaA gene, the oriC sequence, and the 5' partial sequence of the dnaN gene. The analysis revealed fragments with reduced electrophoretic mobility, which indicates the presence of curved DNA segments. The analysis of the helical parameter ENDS ratio revealed three bent DNA sites (b1, b2, and b3) located in the rpmH-dnaA intergenic region, the dnaA gene, and the oriC 5' end, respectively. The chromosomal segment of X. fastidiosa analyzed here is rich in phased AT tracts and in CAnT motifs. The 2-D projection indicated a segment whose structure was determined by the cumulative effect of all bent DNA sites. Further, the in silico analysis of the three different bacterial oriC sequences indicated similar negative roll and twist >34.00° values. The DnaA box sequences, and other motifs in them, may be associated with the intrinsic DNA curvature.

Don Bent

Campus Mailman

An approximation method for evaluating centrifugal distortion constants in XH2 bent symmetric molecules

University of Cochin