Search

Chromium (III) picolinate, [Cr(pic)3], was synthesized and characterized by solid electron paramagnetic resonance (EPR) in both room and frozen temperatures. Broad EPR signals of the mer-[Cr(pic)3] complex were found for the solid with g values of 3.45 and 3.47 at room temperature and frozen at 100 K, respectively. This result indicates that the mer-[Cr(pic)3] system has a rhombic character and a large zero-field splitting D value. In addition, its purity was confirmed by elementary analysis, atomic absorption spectroscopy (AAS), HPLC, UV–Vis, ATR-FTIR, Raman spectroscopy, and ESI-mass spectrometry. DFT calculations reveal that the most likely pathway for the acid-catalyzed [Cr(pic)3] aquation is via a two-step mechanism, which is in excellent agreement with the experimental result. Furthermore, the importance of outer sphere solvation was investigated with the addition of up to three explicit water molecules in the second coordination sphere. The enthalpies of activation (ΔH‡) for water-water exchange on the D pathway of [Cr(pic)(H2O)4]2+… nH2O complexes are found to decrease for n = 0–3 (64, 58, 56, and 53 kJ mol−1, respectively).

PURPOSE:The aim of this study was to quantify the prevalence of Fear of Cancer Recurrence (FCR) in patients with a prior haematology malignancy surviving more than one year post allogeneic haematopoietic stem cell transplantation (HSCT), and to identify the demographic, medical and psychological factors associated with FCR occurrence. METHOD:Participants were adult allogeneic HSCT recipients who had undergone the procedure for acute leukaemia or other haematological malignancy between the years 2000-2012 in Sydney, Australia. They completed a purpose designed survey and six other validated instruments which assessed FCR, psychological functioning, quality of life, demographic, social and clinical variables. RESULTS:Of the 364 respondents, approximately 11% of the sample lived with severe FCR while only 5% of subjects reported having no FCR. Variables significantly associated with higher FCR included unemployment, a shorter time (years) post-transplant, not attending to health screening (PAP smear), a secondary diagnosis of skin cancer, younger age, referral to a psychiatrist and taking psychotropic medication. Higher psychological distress (depression, anxiety, stress) and lower quality of life made a significant contribution to the prediction of FCR. CONCLUSIONS:Post HSCT follow-up care should include an assessment and discussion regarding FCR to balance both realistic and unrealistic cancer recurrence risks. Managing FCR is one of the most ubiquitous unmet needs of survivors of haematological disease and it is important that HSCT nurses are both aware of the fear, and are equipped with knowledge on how to help patients navigate it with realistic expectations.

Plasma synthesized 2-furaldehyde (PPFDH) amorphous polymer thin films of varying thicknesses were prepared in optimum conditions by a capacitively coupled parallel plate glow discharge reactor at room temperature. The structure, morphology, composition and optical properties of deposited PPFDH thin films have been investigated using X-Ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), Energy dispersive X-Ray spectroscopy (EDS), as well as Ultraviolet–visible (UV–vis) absorption spectroscopy. XRD results confirmed the amorphous nature of the films. The smooth and uniform nature of the PPFDH thin films were observed by SEM images. FTIR analyses of monomer FDH and PPFDH thin films show that structural rearrangement has occurred due to the synthesis process taking place in the chemical structure. IR stretching bands obtained from DFT calculations of the optimized structures of monomer and polymer of 2-furaldehyde are in good agreement with the experimental results. UV–vis absorption spectra in transmittance as well as reflectance mode was utilized to compute absorption coefficient, allowed direct and indirect transition energy gaps, band edge sharpness, Urbach energy, steepness parameter, extinction coefficient, and dispersion and oscillator energy. The oscillator strength, moments of optical spectra, refractive index at infinite wavelength, high frequency dielectric constant, average oscilator strength, complex refractive index, dissipation factor, optical conductivity and skin depth were also determined by using measured UV–vis transmittance and reflectance spectra.

The synthesis and characterization of mono-, bis- and tris-glycinatochromium(III) complexes by elemental analysis, UV–Vis, electron paramagnetic resonance (EPR), ATR-FTIR and Raman spectroscopy has been performed in this work. IR stretching bands obtained from DFT calculations of the mono-, bis- and tris-glycinatochromium(III) complexes are in good agreement with experimental data. Different mechanistic pathways were explored for the water exchange reactions of [Cr(+NH3CH2COO−)(H2O)5]3+ and its conjugate base species including, associative interchange (Ia), and dissociative (D) mechanisms. The lowest activation enthalpies for the mono- and bis-complexes are obtained for the Ia pathways with explicit outer sphere solvation (88 and 76 kJ mol−1), which are in good agreement with the experimental values (87 and 75 kJ mol−1). In comparison, tris-glycinatochromium(III) undergoes aquation via the dissociative (D) mechanism. Investigation of these systems in the pH range ∼3.0 to ∼8.5 by UV–Vis monitoring, helps identify the speciation of these complexes in physiological environments.

The price of carbon emitted by thermal plants has always been a favorite topic of researchers and policy makers. A substitute price for CO2 is calculated in this study based on real-time payments through government tariffs. These payments aim to mitigate CO2 emission caused by unregulated electricity generation. The total CO2 produced by the thermal plants of 10 European countries is shown in this study. The government's payment for each technology is utilized to clear the final CO2 abatement cost. The substitute price of avoiding CO2 emission (SPAC) for each technology and country is estimated. SPAC is basically the price that each country pays to avoid producing CO2. The conducted survey shows that the SPAC of the 10 European countries ranges from 63 to 2951 Euros depending on the type of technology used and the country's policy. Results confirm a competitive payment by governments only for German and UK hydro and UK wind technologies. Comparison of the countries’ payments for renewable energies and CO2 market price shows that governments incurred an inefficient payment of liquidity as a carbon mitigation policy.

The mechanism for aquation of dihalotetraaquachromium(III) complexes (trans-[Cr(H2O)4TX]+, where X or T = Cl, Br, or I), including a common component of many nutritional supplements (X, T = Cl) has been investigated using density functional theory. A number of mechanistic pathways were explored including associative interchange (Ia), and dissociative (D) mechanisms. The overall activation enthalpy for the D pathway of the dichloro (trans-[Cr (H2O)4Cl2]) system calculated at the PBE0/cc-pVDZ level, with inclusion of an explicit outer sphere water molecule and in aqueous solution (PCM), is in excellent agreement with the experimental result. The results provide a detailed understanding of the mechanism for the hydrolysis of trans-Cr(III) complexes, which could be useful in understanding the speciation of Cr(III) complexes in physiological environments.

The mechanism for the substitution reactions of halopentaaquachromium(III) complexes in the series, [CrX(H2O)5]2+, where X = F−, Cl−, Br−, or I− have been investigated using density functional theory. Several different mechanistic pathways were explored including associative interchange (Ia), dissociative (D) and the associatively activated dissociation mechanisms (Da). The lowest overall activation enthalpy (ΔH‡) obtained for the fluoride system is for the Ia pathway, with immediate proton abstraction leading to the formation of HF and the conjugate base. For the chloride, bromide and iodide systems the Da pathway has the lowest ΔH‡ values. Activation enthalpies determined at the PBE0/cc-pVDZ level, in aqueous solution (PCM), are in excellent agreement with the experimental results (MAD is 1.0 kJ mol−1). Reaction profiles were analyzed in terms of activation volumes to explain the observed trends.

A detailed computational investigation of the mechanism for the hydrolytic deamination of cytosine, its cyclobutane cytosine dimer C C, and other 5,6-saturated cytosine analogues was undertaken. The rationale behind this work was twofold: to clearly establish the mechanism for the hydrolytic deamination of cytosine and cytosine analogues by comparing calculated and experimentally known activation energies and secondly, to provide a logical basis for the much lower activation energy barriers for 5,6-saturated cytosine analogues versus cytosine monomer. Energies for all relevant species including intermediates and transition states for all pathways studied were determined using B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p) and G3MP2B3 levels of theory and solvent calculations were performed using both the polarizable continuum model (PCM) and the solvation model on density (SMD). Activation energies, Gibbs energies of activation, ΔH of reaction and ΔG of reaction were calculated for each pathway investigated. Deformation energies as well as the total interaction energy of reactant species were determined for the formation of the key transition state (TS2) which decomposes to form a tetrahedral intermediate in all pathways studied. The overall gas phase activation energies found for the deamination of cytosine and dicytosine with three explicit water molecules are in good agreement with the experimental values found in the literature. Such good agreement between calculated and experimental results is very strong evidence that the mechanism for the hydrolytic deamination has been correctly determined. Reduced deformation energy required to form the key transition state TS2 for the C5–C6 saturated cytosine analogues has been found to be the main reason for the significantly lower activation energies for their hydrolytic deamination.