Daniel Ruiz

Using recombinant proteins from Lutzomyia longipalpis saliva to estimate human vector exposure in visceral Leishmaniasis endemic areas.

Background Leishmania is transmitted by female sand flies and deposited together with saliva, which contains a vast repertoire of pharmacologically active molecules that contribute to the establishment of the infection. The exposure to vector saliva induces an immune response against its components that can be used as a marker of exposure to the vector. Performing large-scale serological studies to detect vector exposure has been limited by the difficulty in obtaining sand fly saliva. Here, we validate the use of two sand fly salivary recombinant proteins as markers for vector exposure. Methodology/principal findings ELISA was used to screen human sera, collected in an area endemic for visceral leishmaniasis, against the salivary gland sonicate (SGS) or two recombinant proteins (rLJM11 and rLJM17) from Lutzomyia longipalpis saliva. Antibody levels before and after SGS seroconversion (n = 26) were compared using the Wilcoxon signed rank paired test. Human sera from an area endemic for VL which recognize Lu. longipalpis saliva in ELISA also recognize a combination of rLJM17 and rLJM11. We then extended the analysis to include 40 sera from individuals who were seropositive and 40 seronegative to Lu. longipalpis SGS. Each recombinant protein was able to detect anti-saliva seroconversion, whereas the two proteins combined increased the detection significantly. Additionally, we evaluated the specificity of the anti-Lu. longipalpis response by testing 40 sera positive to Lutzomyia intermedia SGS, and very limited (2/40) cross-reactivity was observed. Receiver-operator characteristics (ROC) curve analysis was used to identify the effectiveness of these proteins for the prediction of anti-SGS positivity. These ROC curves evidenced the superior performance of rLJM17+rLJM11. Predicted threshold levels were confirmed for rLJM17+rLJM11 using a large panel of 1,077 serum samples. Conclusion Our results show the possibility of substituting Lu. longipalpis SGS for two recombinant proteins, LJM17 and LJM11, in order to probe for vector exposure in individuals residing in endemic areas.

Asymmetric Hybrid Silica Nanomotors for Capture and Cargo Transport: Towards a Novel Motion‐Based DNA Sensor

An innovative self-propelled nanodevice able to perform motion, cargo transport, and target recognition is presented. The system is based on a mesoporous motor particle, which is asymmetrically functionalized by the attachment of single-stranded DNA onto one of its faces, while catalase is immobilized on the other face. This enzyme allows catalytic decomposition of hydrogen peroxide to oxygen and water, giving rise to the driving force for the motion of the whole system. Moreover the motor particles are able to capture and transport cargo particles functionalized with a noncomplementary single-stranded DNA molecule, only if a specific oligonucleotide sequence is present in the media. Functionalization with characteristic oligonucleotide sequences in the system implies a potential for further developments for lab-on-chip devices with applications in biomedical applications.

Dendrimeric hyperbranched alkylaromatic polyradicals with mesoscopic dimensions and high-spin ground states

Abstract Molecular design to super high-spin stable organic molecules with dendrimeric character is described. The synthesis of some polyradicals with this characteristics are also reported.

Study of intervalence bands due to reversible intramolecular electron transfer phenomena in purely organic mixed-valence high-spin molecules

Abstract Up to now, few examples of reversible electron intramolecular transfer phenomena in purely organic mixed-valence molecules have been studied in detail. We present the first example of a purely organic molecule in which, in addition to the observation of an optical electron transfer between open-shell and anionic sites, two radical centers remain ferromagnetic ally coupled inside the molecule. The intervalence band which arises from the optical ET is clearly observed in the far NIR range and is quantitatively analyzed by means of an ad hoc model. Since these properties are rather unusual for purely organic compounds, even separately, this and similar molecules offer us a unique chance for studying the reciprocal influence between electron transfer and strong magnetic coupling in organic systems.

Coexistence of Ferromagnetic Coupling and Intramolecular Electron Transfer in a Purely Organic Mixed-Valence Molecule with a Triplet Ground State

Abstract The magnetic study of a purely organic biradical anion presenting electron transfer and ferromagnetic coupling between two radical centers simultaneously is discussed. The mixed-valence molecule was first generated electrochemically and the electron transfer was detected by optical spectroscopy. ESR measurements not only made the determination of the ground state possible, but also gave further evidence of transient site-localisation of the extra electron.

Electromagnetic absorption of semiconductor 2D Majorana nanowires

We calculate the cross section for the electromagnetic absorption of planar 2D Majorana nanowires. The electromagnetic field is described in the dipole approximation. We discuss the signatures on the cross section of a near-zero-energy mode. A low energy peak for transverse polarization, absent in the longitudinal one, reveals the presence of the Majorana-like state. This peak is relatively robust against the thermal smearing of the level occupations. We consider the influence of optical masks hiding parts of the nanowire from the radiation.