Bayesian estimation and selection of nonlinear vector error correction models: The case of the sugar-ethanol-oil nexus in Brazil

Nonlinear adjustment toward long-run price equilibrium relationships in the sugar-ethanol-oil nexus in Brazil is examined. We develop generalized bivariate error correction models that allow for cointegration between sugar, ethanol, and oil prices, where dynamic adjustments are potentially nonlinear functions of the disequilibrium errors. A range of models are estimated using Bayesian Monte Carlo Markov Chain algorithms and compared using Bayesian model selection methods. The results suggest that the long-run drivers of Brazilian sugar prices are oil prices and that there are nonlinearities in the adjustment processes of sugar and ethanol prices to oil price but linear adjustment between ethanol and sugar prices.

Anion-pi, Lone-Pair-pi, pi-pi and Hydrogen-Bonding Interactions in a Cu-II Complex of 2-Picolinate and Protonated 4,4 '-Bipyridine: Crystal Structure and Theoretical Studies

A Cu-II complex of protonated 4,4'-bipyridine (Hbyp) and 2-picolinate (pic), [Cu-2(pic)(3)(Hbyp)(H2O)(ClO4)(2)], has been synthesised and characterised by single-crystal X-ray analysis. The structure consists of two copper atoms that have different environments, bridged by a carboxylate group. The equatorial plane is formed by the two bidentate picolinate groups in one Cu-II, and one picolinate, one monodentate 4,4'-bipyridyl ligand and a water molecule in the other. Each copper atom is also weakly bonded to a perchlorate anion in an axial position. One of the coordinated perchlorate groups displays anion-pi interaction with the coordinated pyridine ring. The noncoordinated carboxylate oxygen is involved in lone-pair (l.p.)-pi interaction with the protonated pyridine ring. In addition there are pi-pi and H-bonding interactions in the structure. Bader's theory of "atoms in molecules" (AIM) is used to characterise the anion-pi and l.p.-pi interactions observed in the solid state. A high-level ab initio study (RI-MP2/aug-cc-pVTZ level of theory) has been performed to analyse the anion-pi binding affinity of the pyridine ring when it is coordinated to a transition metal and also when the other pyridine ring of the 4,4'-bipyridine moiety is protonated. Theoretical investigations support the experimental findings of an intricate network of intermolecular interactions, which is characterised in the studied complex, and also indicate that protonation as well as coordination to the transition metal have important roles in influencing the pi-binding properties of the aromatic ring. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Binding studies of a protonated dioxatetraazamacrocycle with carboxylate substrates

The tetraprotonated form of the dioxatetraazamacrocycle, 6,19-dioxa-3,9,16,22-tetraaza[22.2.2.2(11,14)]-triaconta-1(26),11,13,24, 27,29-hexaene, (H4L1)(4+), was used as the receptor for binding studies with carboxylate anionic substrates of different shapes, sizes, and charges [succinate (suc(2-)), cyclo- hexanetricarboxylate (cta(3-)), phthalate (ph(2-)), isophthalate (iph(2-)), terephthalate (tph(2-)), and benezenetricarboxylate (btc(3-))]. Association constants were determined by potentiometry in aqueous solution at 298.2 K and 0.10 M KCl and by H-1 NMR titration in D2O. The strongest association was found for the btc3- anion at 5-7 pH region. From both techniques it was possible to establish the binding preference trend of the receptor for the different substrates, and the H-1 NMR spectroscopy gave important suggestions about the type of interactions between partners and the location of the substrates in the supramolecular entities formed. The effective binding constants at pH 6 follow the order: btc(3-)>iph(2-)>cta(3-) =ph(2-)>tph(2-)>suc(2-). All the studies suggest that the anionic substrates bind to the receptor via N-H center dot center dot center dot O = C hydrogen bonds and electrostatic interactions, and the aromatic substrates can also establish pi-pi stacking interactions. The crystal structures of (H4L1)(4+) and its supramolecular assemblies with ph(2-) and tph(2-) were determined by X-ray diffraction. The last two structures showed that the association process in solid state occurs via multiple N-H center dot center dot center dot O = C hydrogen bonds with the anionic substrate located outside the macrocyclic cavity of the receptor. Molecular dynamics simulations carried out for the association of (H4L1)(4+) with tph(2-) and btC(3-) in water solution established at atomic level the existence of all interactions suggested by the experimental studies, which act cooperatively in the binding process. Furthermore, the binding free energies were estimated and the values are in agreement with the experimental ones, indicating that the binding of these two anionic substrates occurs into the receptor cavity. However, the tph(2-) has also propensity to leave the macrocyclic cavity and its molecular recognition can also happen at the top of the receptor. (C) 2008 Elsevier Ltd. All rights reserved.

Effect of ethanol on the micellization and gelation of Pluronic P123

In certain applications copolymer P123 (E21P67E21) is dissolved in water-ethanol mixtures, initially to form micellar solutions and eventually to gel. For P123 in 10, 20, and 30 wt % aqueous ethanol we used dynamic light scattering from dilute solutions to confirm micellization, oscillatory rheometry, and visual observation of mobility (tube inversion) to determine gel formation in concentrated solutions and small-angle X-ray scattering (SAXS) to determine gel structure. Except for solutions in 30 wt % aqueous ethanol, a clear-turbid transition was encountered on heating dilute and concentrated micellar solutions alike, and as for solutions in water alone (Chaibundit et al. Langmuir 2007, 23, 9229) this could be ascribed to formation of wormlike micelles. Dense clouding, typical of phase separation, was observed at higher temperatures. Regions of isotropic and birefringent gel were defined for concentrated solutions and shown (by SAXS) to have Cubic (fcc and hcp) and hexagonal structures, consistent with packed spherical and elongated micelles, respectively. The cubic gels (0, 10, and 20 wt % ethanol) were clear, while the hex gels were either turbid (0 and 10 wt % ethanol), turbid enclosing a clear region (20 wt % ethanol), or entirely clear (30 wt % ethanol). The SAXS profile was unchanged between turbid and clear regions of the 20 wt % ethanol gel. Temperature scans of dynamic moduli showed (as expected) a clear distinction between high-modulus cubic gels (G'(max) approximate to 20-30 kPa) and lower modulus hex gels (G'(max) < 10 kPa).

Substance P released by TRPV1-expressing neurons produces reactive oxygen species that mediate ethanol-induced gastric injury

Although neurokinin 1 receptor antagonists prevent ethanol (EtOH)-induced gastric lesions, the mechanisms by which EtOH releases substance P (SP) and SP damages the mucosa are unknown. We hypothesized that EtOH activates transient receptor potential vanilloid 1 (TRPV1) on sensory nerves to release SP, which stimulates epithelial neurokinin 1 receptors to generate damaging reactive oxygen species (ROS). SP release was assayed in the mouse stomach, ROS were detected using dichlorofluorescein diacetate, and neurokinin 1 receptors were localized by immunofluorescence. EtOH-induced SP release was prevented by TRPV1 antagonism. High dose EtOH caused lesions, and TRPV1 or neurokinin 1 receptor antagonism and neurokinin 1 receptor deletion inhibited lesion formation. Coadministration of low, innocuous doses of EtOH and SP caused lesions by a TRPV1-independent but neurokinin 1 receptor-dependent process. EtOH, capsaicin, and SP stimulated generation of ROS by superficial gastric epithelial cells expressing neurokinin 1 receptors by a neurokinin 1 receptor-dependent mechanism. ROS scavengers prevented lesions induced by a high EtOH dose or a low EtOH dose plus SP. Gastric lesions are caused by an initial detrimental effect of EtOH, which is damaging only if associated with TRPV1 activation, SP release from sensory nerves, stimulation of neurokinin 1 receptors on epithelial cells, and ROS generation.

Ethanol elicits and potentiates nociceptor responses via the vanilloid receptor-1

The vanilloid receptor-1 (VR1) is a heat-gated ion channel that is responsible for the burning sensation elicited by capsaicin. A similar sensation is reported by patients with esophagitis when they consume alcoholic beverages or are administered alcohol by injection as a medical treatment. We report here that ethanol activates primary sensory neurons, resulting in neuropeptide release or plasma extravasation in the esophagus, spinal cord or skin. Sensory neurons from trigeminal or dorsal root ganglia as well as VR1-expressing HEK293 cells responded to ethanol in a concentration-dependent and capsazepine-sensitive fashion. Ethanol potentiated the response of VR1 to capsaicin, protons and heat and lowered the threshold for heat activation of VR1 from approximately 42 degrees C to approximately 34 degrees C. This provides a likely mechanistic explanation for the ethanol-induced sensory responses that occur at body temperature and for the sensitivity of inflamed tissues to ethanol, such as might be found in esophagitis, neuralgia or wounds.

Review of the potential for co-firing of cassava rhizome for generating heat and power in cassava based bio-ethanol plant in Thailand

Biomass is an important source of energy in Thailand and is currently the main renewable energy source, accounting for 40% of the renewable energy used. The Department of Alternative Energy and E�ciency (DEDE), Ministry of Thailand, has been promoting the use of renewable energy in Thailand for the past decade. The new target for renewable energy usage in the country is set at 25% of the �nal energy demand in 2021. Thailand is the world’s fourth largest producer of cassava and this results in the production of signi�cant amounts of cassava rhizome which is a waste product. Cassava rhizome has the potential to be co-�red with coal for the production of heat and power. With suitable co-�ring ratios, little modi�cation will be required in the co-�ring technology. This review article is concerned with an investigation of the feasibility of co-�ring cassava rhizome in a combined heat and power system for a cassava based bio-ethanol plant in Thailand. Enhanced use of cassava rhizome for heat and power production could potentially contribute to a reduction of greenhouse gas emissions and costs, and would help the country to meet the 2021 renewable energy target.