Structural and vibrational analysis of thymoquinone.

The molecular structure of 2-isopropyl-5-methyl-1,4-benzoquinone, C(6)O(2)H(2) (CH(3))(3)CH, has been optimized using methods based on density functional theory (DFT) and Moller-Plesset second-order perturbation theory (MP2). As regards C(6)O(2)H(2) (CH(3))(3)CH, two populated conformations with C(1) (trans) and C(s) (cis) symmetries are obtained, the former being more stable than the latter. The theoretical data indicate that although both anti and cis conformers are possible by rotation about the C-C bond, the preferred conformation is trans. The effects governing the torsion barriers and preferred conformations were analyzed at B3LYP/6-311++G** level. The atoms in molecules (AIM) theory and natural bond orbital (NBO) analysis was applied to the cis and trans conformers in order to detect intramolecular contacts. Furthermore, the infrared spectra for the gas and solid phases and the Raman spectrum for the solid one, were recorded and the observed bands assigned to the vibrational modes.

Characterization and crystal structure of 2R-(-)-6-hydroxytremetone from Xenophyllum poposum (Phil.) V.A. Funk.

2R-(-)-6-Hydroxytremetone (C13H14O3) is a bioactive metabolite isolated from Xenophyllum poposum (Phil.) V.A. Funk. (ex. Werneria poposa Phil.), a member of the Asteraceae. Various pharmacological properties attributed by popular medicine to benzofurane derivatives prompted their physical and chemical characterization. The obtained substance was characterized by melting point, optic rotation, ultraviolet spectrum, 1HRMN, 13CRMN, infrared spectroscopy, and thermo-analytical techniques. The molecular structure of 2R-(-)-6-hydroxytremetone was determined by single crystal X-rays diffraction methods. The substance crystallizes in the monoclinic space group P2(1) with a = 8.767(2) A, b = 5.423(1) A, c = 24.301(4) A, beta = 90.52(2) degrees , and two independent but very similar molecules of the same handedness per asymmetric unit (Z = 4). Both molecules have the phenyl ring and its attached oxydryl and methyl ketone groups nearly co-planar to one another and are stabilized by a strong OH ... Oketone intra-molecular bond (Ohydroxyl ... Oketone distances of 2.529 and 2.536 A; O-H ... Oketone angles of 146.4 and 143.9 degrees , respectively).

Crystal structure determination of thymoquinone by high-resolution X-ray powder diffraction.

The crystal structure of 2-isopropyl-5-methyl-1,4-benzoquinone (thymoquinone) and its thermal behavior--as necessary physical and chemical properties--were determined in order to enhance the current understanding of thymoquinone chemical action by using high resolution x-ray powder diffraction, Fourier transform infrared spectroscopy (FTIR), and 3 thermo-analytical techniques thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The findings obtained with high-resolution x-ray powder diffraction and molecular location methods based on a simulated annealing algorithm after Rietveld refinement showed that the triclinic unit cell was a = 6.73728(8) A, b = 6.91560(8) A, c = 10.4988(2) A, alpha = 88.864(2) degrees, beta = 82.449(1) degrees, gamma = 77.0299(9) degrees; cell volume = 472.52(1) A3, Z = 2, and space group P1. In addition, FTIR spectrum revealed absorption bands corresponding to the carbonyl and C-H stretching of aliphatic and vinylic groups characteristically observed in such p-benzoquinones. Also, a chemical decomposition process starting at 65 degrees C and ending at 213 degrees C was noted when TGA was used. DSC allowed for the determination of onset at 43.55 degrees C and a melting enthalpy value of DeltaH(m) = 110.6 J/g. The low value obtained for the fusion point displayed a van der Waals pattern for molecular binding, and the thermograms performed evidence that thymoquinone can only be found in crystalline triclinic form, as determined by DRX methods.

Manual autotraction: preliminary study on the effectiveness of a new device for back pain treatment.

AIM: The aim of this study is to assess the efficacy of a new, simple and cheap device of manual autotraction (MAT), in comparison with Natchev's autotraction system. METHODS: Fifty-four patients, with lumbalgia or sciatalgia for more than 4 months and disc herniation or protrusion at computed tomography (CT) or nuclear magnetic resonance (NRM), have been selected, at random, in a randomized control trial. Patients have been treated by MAT or by Natchev's autotraction. Treatments' efficacy has been assessed through the differences in visual analogic scale (VAS) for pain, and Backill scale for disability, before and after therapy (diffVAS and diffBi). The results of the 2 autotraction's devices have been compared in order to distinguish their differences. The results have been considered significant if p<0.05. RESULTS: Both treatments proved to be effective (MAT: diffVAS p<0.0001, diffBackill p<0.001; Natchev's group: diffVAS p<0.0001, diffBackill p<0.001). No significant difference of efficacy emerges between the treatments in diffVAS (p=0.199) and diffBi (p=0.906), and a greater efficacy of both in case of pain with nocturnal aggravation (MAT group: diffVAS: p=0.001; Natchev's group: p=0.001). CONCLUSIONS: The results of this study show an equal efficacy of MAT compared to the known Natchev's system, so it could be equally proposed like a simple conservative treatment in disc protrusion or herniation without surgery indication.

Foliar antioxidant status of adult Mediterranean oak species (Quercus ilex L. and Q. pubescens Willd.) exposed to permanent CO2-enrichment and to seasonal water stress.

Foliar antioxidants were measured in adult individuals of holm oak (Quercus ilex L.) and white oak (Q. pubescens Willd.) growing in the field either within the vicinity of natural CO2 springs or at a nearby control site under ambient CO2, which had been previously exposed to either daily irrigation or no irrigation. In oak trees permanently exposed to elevated CO2 the activities of antioxidant enzymes tended to be lower and the ascorbate pool was larger and more in reduced form, suggesting an attenuation of the oxidative risk in the CO2-enriched trees. In the enriched individuals of both species. the imposition of water shortage significantly increased the size of the glutathione pool and the total superoxide dismutase activity in a species-specific manner. Moreover, water-stressed trees exposed to elevated CO2 tended to have higher catalase and ascorbate peroxidase activities than water-stressed control trees. Such changes may reflect the need for an enhanced compensatory effort when trees acclimated to elevated CO2 are exposed to oxidative stress-promoting environmental factors, such as water shortage.

Comparative field water relations of three Mediterranean shrub species co-occurring at a natural CO(2) vent.

Annual variations in the water relations and stomatal response of Erica arborea, Myrtus communis and Juniperus communis occurring at a natural CO(2) vent were analysed under Mediterranean field conditions. A distinct gradient of CO(2)concentration ([CO(2)]) exists between two sites near a natural CO(2)-emitting vent, with higher [CO(2)] (700 micromol mol(-1)) in the proximity of the CO(2) spring. Plants at the CO(2) spring site have been growing for generations at elevated [CO(2)]. At both sites, maximum leaf conductance was related to predawn shoot water potential. The effects of water deficits during the summer drought were severe. Leaf conductance and water potential recovered after major rainfalls in September to predrought values. Strong relationships between leaf conductance, predawn water potential, and leaf-specific hydraulic resistance are consistent with the role of stomata in regulating plant water status. Considerable between-species variation in sensitivity of water potentials and stomatal characters to elevated [CO(2)] were observed. Common to all the shrubs were a reduction in leaf conductance and an increase in water potentials in response to elevated [CO(2)]. Elevated [CO(2)] decreased the sensitivity of leaf conductance to vapour pressure deficit. Morphological characters (including stomatal density and degree of sclerophylly) showed site-dependent variations, but degree and sign of such changes varied with the species and/or the season. Measurements of discrimination against (13)C provided evidence for long-term decreases of water use efficiency in CO(2) spring plants. Analysis of C isotope composition suggested that a downward adjustment of photosynthetic capacity may have occurred under elevated [CO(2)]. Elevated [CO(2)] effects on water relations and leaf morphology persisted in the long term, but the three shrubs growing in the same environment showed species-specific responses.

The impact of elevated CO2 on growth and photosynthesis in Agrostis canina L. ssp. monteluccii adapted to contrasting atmospheric CO2 concentrations.

The aim of this study was to characterise growth and photosynthetic capacity in plants adapted to long-term contrasting atmospheric CO2 concentrations (C a). Seeds of Agrostis canina L. ssp. monteluccii were collected from a natural CO2 transect in central-western Italy and plants grown in controlled environment chambers at both ambient and elevated CO2 (350 and 700 µmol mol-1) in nutrient-rich soil. Seasonal mean C a at the source of the plant material ranged from 610 to 451 µmol CO2 mol-1, derived from C4 leaf stable carbon isotope discrimination (δ13C). Under chamber conditions, CO2 enrichment stimulated the growth of all populations. However, plants originating from elevated C a exhibited higher initial relative growth rates (RGRs) irrespective of chamber CO2 concentrations and a positive relationship was found between RGR and C a at the seed source. Seed weight was positively correlated with C a, but differences in seed weight were found to explain no more than 34% of the variation in RGRs at elevated CO2. Longer-term experiments (over 98 days) on two populations originating from the extremes of the transect (451 and 610 µmol CO2 mol-1) indicated that differences in growth between populations were maintained when plants were grown at both 350 and 700 µmol CO2 mol-1. Analysis of leaf material revealed an increase in the cell wall fraction (CWF) in plants grown at elevated CO2, with plants originating from high C a exhibiting constitutively lower levels but a variable response in terms of the degree of lignification. In vivo gas exchange measurements revealed no significant differences in light and CO2 saturated rates of photosynthesis and carboxylation efficiency between populations or with CO2 treatment. Moreover, SDS-PAGE/ LISA quantification of leaf ribulose bisphosphate carboxylase/oxygenase (Rubisco) showed no difference in Rubisco content between populations or CO2 treatments. These findings suggest that long-term adaptation to growth at elevated CO2 may be associated with a potential for increased growth, but this does not appear to be linked with differences in the intrinsic capacity for photosynthesis.

Isotopic carbon discrimination and leaf nitrogen content of Erica arborea L. along a CO(2) concentration gradient in a CO(2) spring in Italy.

We studied a Mediterranean species (Erica arborea L.) growing in a CO(2) spring in Italy that was naturally exposed for generations to a gradient of atmospheric CO(2) concentrations. The CO(2) concentration gradient to which different individual plants were exposed was determined by an indirect method based on radioisotope analysis. The stable carbon isotope ratio of sampled leaves was determined by mass spectrometry, and isotopic discrimination was then calculated. Leaf nitrogen, specific leaf area, total soil nitrogen, soil organic matter content and soil pH were also measured. In one group of plants, grown on a homogeneous soil and exposed to moderate CO(2) enrichment, isotopic discrimination was significantly reduced in response to increasing CO(2) concentrations, whereas the intercellular CO(2) concentration and leaf nitrogen content were almost unaffected. In a second group of plants, grown along a gradient of CO(2) concentration and soil nitrogen content, leaf nitrogen content was reduced when nitrogen availability was limiting. However, when soil nitrogen was available in excess, even very high CO(2) concentrations did not result in increased discrimination or reduced leaf nitrogen content in the long term. The results are discussed with respect to current theories about the long-term CO(2) response of plants based on several years of experimentation with elevated atmospheric CO(2) concentrations under controlled conditions.

Restoration of gait with orthoses in thoracic paraplegia: a multicentric investigation.

Twenty-eight patients with complete T3-12 traumatic paraplegia were fitted with hip guidance orthosis (HGO, four cases), reciprocating gait orthosis (RGO, 13 cases) or advanced reciprocating gait orthosis (ARGO, 11 cases). Patients were enrolled for 2 months-6 years (median 5 months) in six Italian rehabilitation centres engaged in a common prospective protocol, including a 6 month follow up. After 12-84 (median 20) rehabilitation sessions over a 3-16 week (median 7) period of specific training all of the patients could perform don-doff manoeuvres autonomously in 2.5-15 min (median 6.4), and could walk at least 30 m with a walker (15 cases) or forearm crutches (13 cases) at 10-50 cm/s (median 16.6). HGO patients tended to walk more slowly than the others. None of them could walk upstairs, while three out of 13 RGO patients and seven out of 11 ARGO patients could. Six months later, 21 patients still used the orthosis for 0.5-3 h daily (median 2). Only four patients used the orthosis to walk outdoors. As a median they could still attain the speed recorded at discharge. Six patients had decided to abandon the device, while one was wheelchair bound due to a recent spinal intervention. Neither clinical, demographic or locomotor variables, nor centre and type of orthosis appeared to be predictive of abandonment of the device. During either the training or the follow up periods, six out of 13 RGO and seven out of 11 ARGO had to be repaired by the orthotist 1-10 times (median 3). Thus, in our sample of paraplegics, walking with these orthoses appeared to be a promising form of exercise rather than an alternative to wheelchair locomotion.

Ultrasound emission after cycles of water stress in Picea abies.

The relationships among rate of ultrasound acoustic emission (AE), xylem water potential and transpiration rate were investigated in 5-year-old potted saplings of Picea abies Karst. after cycles of water stress. Water-stressed plants displayed minimum xylem water potentials of -3.9 MPa, near-zero transpiration rates and up to 45 AE counts per minute. After rewatering, water-stressed plants no longer produced AEs. Well-watered control plants produced only a small number of ultrasonic AEs. After three cycles of water stress (lasting 24 days in total), it was estimated that about two-thirds of the functional tracheids were embolized. The concomitant reduction in hydraulic conductance was about 70%.