Probe functionalization with a Rhop-3 antibody: toward a Rhop-3 antigen immunosensor for detection of malaria

The antibody specific for the malaria protein, Rhop-3, and FL-Rhop-3, were immobilized on the surface of a gold electrode modified with cysteamine. Colloidal gold was used to enhance the detection signal for Rhop-3 antigens. The Rhop-3 antibody was also immobilized on gold electrodes preactivated with dithiobis(succinimidyl proprionate) (DSP). Immobilization was performed at room temperature and at 37 °C. Cyclic voltammetry (CV) was used to monitor the interaction between the immobilized antibody and its cognate antigen in solution, using ferricyanide, K₃Fe(CN)₆, as reporting electroactive probe. Tests indicate recognition of Rhop-3 protein by the immobilized antibody. Antigen recognition was enhanced by incubation at 37 °C compared with room-temperature incubation. Our results suggest that an immunosensor can be developed and optimized to aid detection of Rhop-3 antigens in samples from malaria patients. As far as we are aware, this is the first amperometric immunosensor targeting Rhop-3 antigen as a malaria biomarker.     

Crystal Structure Determination for Eugenyl Acetate

Abstract  Essential oils are good candidates for the substitution of conventional medicinal treatments. Many articles and patents for their use have been published in recent years. The most attractive aspects of using essential oils as medicaments are their natural source and rapid permeability. Besides permeability, the solubility behavior of a drug is a key determinant of its oral bioavailability. Based on these characteristics, the aim of this study was to synthesize an essential oil derivative compound, using the raw oil extracted from Syzygium aromaticum L., without previous purification. The Eugenol molecular modification may diminish the problems of water solubility and bioavailability. The Eugenyl acetate molecule was characterized and its molecular modification investigated, including its structural properties and stereochemistry. This study was performed applying techniques, such as carbon-13 nuclear magnetic resonance spectroscopy (C-13 NMR), X-ray crystallographic analysis (XRD), powder X-ray diffraction (PXRD) and microscopic recording. Graphical Abstract  Eugenol and its structure have been known for many years, where as Eugenyl acetate’s structure has never been elucidated nor confirmed until now.      

2s and 2p X-ray photoelectron spectra of Ti4+ ion in TiO2

A detailed experimental study of the 2s- and 2p XPS spectra of TiO₂ revealed new (charge-transfer) shake-up satellite structures (at 4.0–5.0 eV from the main peaks) which can be explained using molecular orbital representation. The satellite peaks, situated at about 26 eV from the main peaks, the origin of which was in doubt in the previously reported works are shown conclusively in the present investigation to be energy loss peaks. The relative energies and intensities of the observed satellites are presented and the theoretical implications of the work are discussed.     

The Geometry of Tetrathiotetracene as a Donor in Charge Transfer Complexes: an ab Initio Theoretical Investigation

Ab initio STO-3G calculations are performed on both tetracene (T) and tetrathiotetracene (TTT), and their respective radical-cations. Mulliken populations indices and nodal structure of the HOMO explain the geometry changes of these compounds upon ionization. The strong relaxation energy calculated for tetrathiotetracene, and its low first ionization potential, are related to the grafting of the two disulfide bridges and largely justify the peculiar behavior of TTT upon charge transfer     

Simulation of environmental effects on coherent quantum dynamics in many-body systems

In this paper we describe an application of the trajectory-based semiclassical Liouville method for modeling coherent molecular dynamics on multiple electronic surfaces to the treatment of the evolution and decay of quantum electronic coherence in many-body systems. We consider a model representing the coherent evolution of quantum wave packets on two excited electronic surfaces of a diatomic molecule in the gas phase and in rare gas solvent environments, ranging from small clusters to a cryogenic solid. For the gas phase system, the semiclassical trajectory method is shown to reproduce the evolution of the electronic-nuclear coherence nearly quantitatively. The dynamics of decoherence are then investigated for the solvated systems using the semiclassical approach. It is found that, although solvation in general leads to more rapid and extensive loss of quantum coherence, the details of the coupled system-bath dynamics are important, and in some cases the environment can preserve or even enhance quantum coherence beyond that seen in the isolated system.     

Cholesterol levels and activity of membrane bound proteins: characterization by thermal and electrochemical methods

The long-term goal of this investigation is to study the effects of increased cholesterol levels on the molecular activity of membrane-bound enzymes such as nitric oxide synthase, that are critical in the functioning of the cardiovascular system. In this particular investigation, we used differential scanning calorimetry (DSC) and dielectric thermal analysis (DETA) to study the effect of added cholesterol on melting/recrystallization and dielectric behavior, respectively, of phosphatidylcholine (PC) bilayered thin films. We also used electrochemical methods to investigate the effect of added cholesterol on the redox behavior of the oxygenase domain of nitric oxide synthase as a probe embedded in the PC films. The results show that added cholesterol in the PC films seems to depress the molecular dynamics as indicated by lowered current responses in the presence of cholesterol as well as a slight increase of the transition temperature in the overall two-phase regime behavior observed in PC–cholesterol films. These results are rationalized in the context of the general DSC and DETA behaviors of the PC–chol films.     

Comparative Ab initio analysis of valence XPS data for acenes and paraphenyl oligomers: Application of the molecular-orbital intensity model

The electronic structures of acenes and paraphenyls are approached by ab initio calculations and XPS valence data. Particular attention is drawn to the molecular-orbital intensity model, which proves to be a quite successful means of following the evolution of all the valence orbitals as a function of system size.