The influence of sodium perfluorooctanoate on the conformational transitions of human immunoglobulin

In the field of bioscience, the study of the interactions between blood proteins and fluorinated materials is very important from both theoretical and applied points of view. Fluorinated materials have potential use in drug delivery, as blood substitutes, and in biotechnology. Using a combination of ultraviolet-visible (UV-vis) and ultraviolet-circular dichroism (UV-CD) spectroscopies and ion-selective electrodes, the complete interaction of sodium perfluorooctanoate (SPFO) and the most important immunoglobulin (on a quantitative basis) in human serum, immunoglobulin G (IgG), has been evaluated. The study has been focused on bulk solution. By the application of an SPFO selective electrode, it was determined that there were true specific unions between surfactant molecules and IgG structure. The experimental data were presented as Koltz and Scatchard plots and analyzed on the basis of an empirical Hill equation. The conformational changes at the bulk solution were well characterized by UV-vis and UV-CD spectroscopies. As a consequence of these changes, the protein structure was affected.     

Templated construction of a Zn-selective protein dimerization motif

Here, we report that the approach of metal-templated ligand synthesis can be applied to construct a dimeric protein assembly ((BMOE)RIDC1(2)), which is stabilized by noncovalent interactions and flexible covalent cross-linkers around the Zn templates. Despite its flexibility, (BMOE)RIDC1(2) selectively binds Zn(II) over other divalent metals and undergoes dimerization upon metal binding. Such simultaneous fulfillment of plasticity and selectivity is a hallmark of cellular signaling events that involve ligand/metal-induced protein dimerization.     

Application of DSC–TG and NMR to study the soil organic matter

The environmental concern on soil exploitation, linked to global warming by the Kyoto protocol, is responsible for increasing interest in the understanding of the role of the composition and structure of the soil organic matter (SOM) on soil carbon, C, dynamics. Thermal analysis and nuclear magnetic resonance (NMR) are applied to study the thermal properties, the structure and composition of the SOM of six samples with different C contents in order to improve the interpretation of results given by thermal analysis. Results showed that the direct integral of the combustion peaks obtained by DSC and the percentage of SOM given by TG were both directly related to the quantity of total soil C. Thus, soils with higher C content showed higher energy content too. The combustion temperatures of the curves given by DSC are those reported for labile OM. NMR results indicated the presence of aliphatic C, carbohydrates, and a weak signal in the aromatic C band in all the samples that was not detected in the DSC curves. Only two samples showed carboxyl/carbonyl C which was not detected by DSC also.     

Effect of tretinoin inclusion in dimethyl-beta-cyclodextrins on release rate from a hydrogel formulation

The aim of this work was to study the release, permeation and skin retention profiles of 0.05% tretinoin hydrogel formulations in which tretinoin was in free form or complexed with dimethyl-beta-cyclodextrin in a stoichiometry of 1:4. Theoretically, this complexation will mainly allow to: overcome drug’s low water solubility and low stability; enhance the drug permeation by promoting skin absorption and alleviate drug inducing local irritation. In vitro release, permeation and skin retention tests were performed in both formulations in order to compare the main advantages of this complexation. The influence of the thermodynamic activity on the drug release profile was also investigated. This study proved that tretinoin inclusion complexes formulation with excess of cyclodextrins had better release profile than the free tretinoin formulation. It was concluded that in this study, thermodynamic activity was not the driving force for the release rate improvement observed with cyclodextrins. Probably, this improvement was due to the increased availability of tretinoin near the membrane surface. In fact, the percentage of total drug that had been retained in the skin was 0.41?±?0.08% for complexed tretinoin gel and 0.17?±?0.04% for the free tretinoin gel.     

Assessment of dispersion map impact on the digital back propagation of long-haul fibre-optic links

The back propagation algorithm is one of the best methods known for simultaneous linear and nonlinear impairment mitigation in long-haul fibre-optic links. Better understanding the full potential of such algorithm is key to improve the capacity of future links, whose design is likely to depend on the algorithm performance under different link configurations. In this paper, we carry out a novel and pertinent comparison in terms of the computational complexity requirements of both symmetric and asymmetric back-propagation implementation approaches for different dispersion map configurations, using simple single channel transmission, which results in the proposal of several design rules for the optimized deployment of ultra-long haul optical transport systems. In particular, it is concluded that dispersion unmanaged transmission is preferable in the sense of compatibility with different link design configurations as well as computational complexity requirements and maximum performance that can be achieved.     

Lie Superalgebras Over 𝔤𝔩2

Whereas Holm proved that the ring of differential operators on a generic hyperplane arrangement is finitely generated as an algebra, the problem of its Noetherian properties is still open. In this article, after proving that the ring of differential operators on a central arrangement is right Noetherian if and only if it is left Noetherian, we prove that the ring of differential operators on a central 2-arrangement is Noetherian. In addition, we prove that its graded ring associated to the order filtration is not Noetherian when the number of the consistuent hyperplanes is greater than 1.     

Eleven-dimensional gauge theory for the M-algebra as an Abelian semigroup expansion of \mathfrak{osp} ( 32 | 1 )

A new Lagrangian realizing the symmetry of the M-algebra in eleven-dimensional space-time is presented. By means of the novel technique of Abelian semigroup expansion, a link between the M-algebra and the orthosymplectic algebra is established, and an M-algebra-invariant symmetric tensor of rank six is computed. This symmetric invariant tensor is a key ingredient in the construction of the new Lagrangian. The gauge-invariant Lagrangian is displayed in an explicitly Lorentz-invariant way by means of a subspace separation method based on the extended Cartan homotopy formula.     

p-Almost tangent structures

Rendiconti del Circolo Matematico di Palermo Series 2 - In this paper, we introduce a new type of geometric structures (calledp-almost tangent structures). They are a natural generalization of...     

Numerical analysis of the electric field formulation of an eddy current problem

In this paper we analyze a finite element method for the numerical solution of an eddy current problem in a bounded conducting domain. We use a weak formulation in terms of the electric field and impose non-local non-standard boundary conditions. The unique data are the input current intensities which are imposed by means of some special curves lying on the boundary of the domain. Optimal error estimates are shown and implementation issues are discussed. To cite this article: A. Bermúdez et al., C. R. Acad. Sci. Paris, Ser. I 337 (2003).     

Anaerobically treated wastewater in agricultural irrigation as an alternative for posttreatment in water-demanding zones

Agroindustries usually produce high amounts of wastewaters and are frequently located close to agricultural activities. Agricultural use of treated wastewaters therefore represents a unique opportunity to solve the problem of water supply for irrigation and disposal of treated water at the same time. This article is the result of collaborative work with the biggest Chilean pisco-(a distillated drink prepared from Muscatel wine) producing company at present. Experiments were conducted to establish anaerobic treatability of wastewaters and also irrigation properties of treated water. With the purpose of confirming laboratory results, a full-scale anaerobic plant was built, and treated water is being used to irrigate 3000 eucalypti. The results showed, at both laboratory and full scale, that anaerobic treatment is suitable for the treatment of pisco wastewater, and that nutrient content of treated water can be beneficial for plant growth, reducing the need for fertilizers.