The effects of conformation and intermolecular hydrogen bonding on the structure and IR spectra of flutamide; a study based on the matrix isolation technique, ab initio and DFT calculations.

In this study, stable conformers of flutamide referred to as an anticancer drug were searched through a relaxed potential energy surface scan carried out at the B3LYP/6-31G(d) level of theory. This was followed by geometry optimization and thermochemistry calculations performed with the HF-SCF, MP2, B3LYP methods and the 6-31G(d), 6-311++G(d,p), aug-cc-pvTZ basis sets for each of the determined minimum energy conformers. The results revealed that flutamide has at least five stable conformers and two of them provide the major contribution to the observed matrix isolation infrared (IR) spectra of the molecule. The effects of conformational variety and intermolecular hydrogen bonding interactions on the observed IR spectra of flutamide were interpreted in the light of the vibrational spectral data obtained for the most stable monomer and dimer forms of the molecule at the same levels of theory. Pulay's "Scaled Quantum Mechanical-Force Field (SQM-FF)" method was used in the refinement of the calculated harmonic wavenumbers, IR intensities and potential energy distributions. This scaling method which proved its superiority to both anharmonic frequency calculations and other scaling methods helped us to correctly interpret the remarkable differences between the matrix IR spectra of flutamide in argon and the condensed phase IR spectra of the molecule in solvents such as KBr, H2O, D2O, ethanol and methanol.

An investigation on the structure and group vibrations of balenine molecule by matrix isolation IR spectroscopy, DFT and MP2 based calculations.

Stable conformers of neutral balenine were scanned through molecular dynamics simulations and energy minimizations using Allinger's MM2 force field. For each of the found minimum-energy conformers, geometry optimization and thermochemistry calculations were performed by using B3LYP, MP2, G3MP2B3 methods, 6-31G(d), 6-311++G(d,p) and aug-cc-pvTZ basis sets. The calculation results have indicated that balenine has about twenty stable conformers whose relative energies are in the range of 0-9.5 kcal/mol. Three of these are thought to provide the major contribution to matrix isolation IR spectra of the molecule. Our solvent calculations using the polarized continuum model revealed the stable zwitterion structures which are predicted to dominate IR spectra of balenine in water and heavy water (D2O) solvents. Pulay's SQM-FF method was used in scaling of the harmonic force constants and vibrational spectral data calculated for the neutral and zwitterion structures. These refined calculation data together with those obtained from anharmonic frequency calculations enabled us to correctly interpret the matrix isolation IR spectrum of balenine and the tautomerism-based changes observed in its KBr IR and solution (D2O) IR spectra. The results revealed the crucial role of conformation and zwitterionic tautomerism on the structure and vibrational spectral data of the molecule.

A vibrational spectroscopy study on anserine and its aqueous solutions.

In this study based on vibrational spectroscopic measurements and Density Functional Theory (DFT), we aimed for a reliable interpretation of the IR and Raman spectra recorded for anserine in the solid phase and water (H2O) and heavy water (D2O) solutions. Initial DFT calculations at the B3LYP/6-31G(d) searched possible conformers of the anserine zwitterion using a systematic conformational search. The corresponding equilibrium geometrical parameters and vibrational spectral data were determined for each of the stable conformers (in water) by the geometry optimization and hessian calculations performed at the same level of theory using the polarized continuum model (PCM). The same calculations were repeated to determine the most energetically preferred dimer structure for the molecule and the associated geometry, force field and vibrational spectral data. The harmonic force constants obtained from these calculations were scaled by the Scaled Quantum Mechanical Force Field (SQM) method and then used in the calculation of the refined wavenumbers, potential energy distributions, IR and Raman intensities. These refined theoretical data, which confirm the zwitterion structure for anserine in the solid phase or aqueous solvents, revealed the remarkable effects of intermolecular hydrogen bonding on the structural properties and observed IR and Raman spectra of this molecule.

Bartonella henselae seroprevalence in cattle breeders and veterinarians in the rural areas of Aydin and Denizli, Turkey.

Bartonella henselae infections are usually detected among people who have close contact with animals. Veterinarians and cattle breeders, in particular, are considered as the risk groups for B. henselae infections. In this study, the seroprevalence of antibodies to B. henselae was investigated in these two groups of subjects in the two cities of Aydin and Denizli, which are located in the same region in the southwest of Turkey. Total antibodies to B. henselae were evaluated by indirect immunofluorescence assay in serum samples taken from 63 cattle breeders and 27 veterinarians. Twenty samples (22.2%) were found to react on 1/64 titre with B. henselae antigens. Bartonella henselae seroprevalence was found to be significantly related to age (P = 0.033) and higher in those living in Aydin (P = 0.047). Age was the only independent factor in multivariate analysis (P = 0.008). Seroprevalence was found to be 2-fold higher in those people who had had tick contact (P = 0.093). In conclusion, the physicians in the region should consider B. henselae infection among veterinarians and breeders in their differential diagnosis list of fever of unknown origin.

Early mobilization following anterior fixation with bone graft and metal plate in traumatic cervical fracture dislocations.

Eighteen cases of traumatic fracture dislocation were managed surgically using a technique which involved an anterior cervical approach followed by discectomy, bone graft, and insertion of a metal plate. The patients were mobilized early to prevent the usual complications of bedsores, deep vein thrombosis, pulmonary embolism, chest infection, and contractures. After more than two years of follow-up, no patient has had problems with local infection, screw loosening, neurological deterioration, dysphagia, or persistence of laryngeal nerve paresis. The benefits of this technique, already endorsed by some authors, include reduced morbidity and hospitalization as well as decreased demand on the staff, particularly as required by quadriplegic patients.