Seasonal Variability of a Caryophyllane Chemotype Essential Oil of Eugenia patrisii Vahl Occurring in the Brazilian Amazon

Eugenia patrisii Vahl is a native and non-endemic myrtaceous species of the Brazilian Amazon. Due to few botanical and phytochemical reports of this species, the objective of the present work was to evaluate the seasonal variability of their leaf essential oils, performed by GC and GC-MS and chemometric analysis. The results indicated that the variation in oil yields (0.7 ± 0.1%) could be correlated with climatic conditions and rainy (R) and dry seasons (D). (E)-caryophyllene (R = 17.1% ± 16.0, D = 20.2% ± 17.7) and caryophyllene oxide (R = 30.1% ± 18.4, D = 14.1% ± 19.3) are the major constituents and did not display significant differences between the two seasons. However, statistically, a potential correlation between the main constituents of E. patrisii essential oil and the climatic parameters is possible. It was observed that the higher temperature and insolation rates and the lower humidity rate, which are characteristics of the dry season, lead to an increase in the (E)-caryophyllene contents, while lower temperature and insolation and higher humidity, which occur in the rainy season, lead to an increase in the caryophyllene oxide content. The knowledge of variations in the E. patrisii essential oil composition could help choose the best plant chemical profile for medicinal purposes.     

Gap Space Optimization for NO Removal in a Non‐thermal Plasma Discharge

Given the operational constraints of aerospace ground equipments (AGE), the nonthermal plasma discharge (NTPD) has been identified as a promising technology for their NO_x removal. As part of a program to optimize an NTPD system for this particular application, an investigation of the effect of discharge gap spacing on the electrical and chemical processes that occur in NTPDs was initiated. A number of experiments were performed to examine how the gap spacing affects the NO removal efficiency, discharge characteristics, and chemical reactions in a NTPD device. Gap spacings ranging from 0.8 to 4.0 mm were investigated in this study. An optimum gap spacing for NO removal was observed at approximately 2 mm and, based on the experimental data, a physical explanation for the optimum was developed. The experiments, results and conclusions are discusssed in detail in this paper.     

Quantum chemical study on the abstraction reaction of alkylidenegermylene with oxirane and thiirane

The mechanisms of theion reaction of alkylidenegermylene with oxirane and thiirane have been characterized detail in using density functional theory, as well as ab initio method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies were calculated by CCSD(T)/6-311G(d)//B3LYP/6-311G(d,p) method for the involved conformations. The results show that the reaction pathways for both reactions consist of two ways: (1) the reactants can yield bent products (P1; P4) by syn-isomers; (2) the reactants can also yield three-membered products (P2; P5) by anti-isomers, which then further react with oxirane and thiirane to form the ultimate products (P3-1, P3-2; P6). Furthermore, a comparison with alkylidenecarbene, oxirane, and thiirane was done.     

Role of Bipolar Pulsed DBD on the Growth of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> in Three-Phase Discharge Plasma Reactor

Algae in drinking water supplies often bring about impact on the water treatment. In this study, a bipolar pulsed dielectric barrier discharge system in three-phase discharge plasma reactor was constructed for investigating its ability to control excessive growth of cyanobacteria, Microcystis aeruginosa. Experimental results show there was almost no change in optical density immediately after the interruption of electrical discharge, but the decreasing trend of optical density, cell density and chlorophyll-a content was obvious during the incubation period, indicating a significant residual effect of electrical discharge process on the algal growth inhibition. Scanning electron microscopy investigation of algae revealed surface damage, apparent leakage of intracellular contents and pores formed after electrical discharge process, which showed that algal cells had no potential to survive and grow. Compared with the control sample, it was observed that electrical discharge on the algal extracellular products has almost no residual effect and the growth rate of algae slightly decreased before three days storage. Hydrogen peroxide was produced by electrical discharge in the μM level and showed a first-order decay. But at such level, the external addition of hydrogen peroxide alone is not likely to cause the residual effect. These results implicated that the growth inhibition of M. aeruginosa was mainly caused by electrical discharge process, and it made the algal cells lose ability to survive, demonstrating the considerable potential of such an alternative process for efficient water purification.     

Identification of target organs of copper nanoparticles with ICP-MS technique

Nanosized copper particles are widely used in fields of lubricants, polymers/plastic, metallic coating and ink. Recently, we found that copper particles in different sizes can lead to different toxicological effects. To clarify the target organs of copper particles of different sizes, the inductively coupled plasma mass spectroscopy (ICP-MS) was employed to evaluate the distribution of copper in different organs of mice after a single dose oral exposure. The results suggest that the main target organs for copper nanoparticles are kidney, liver and blood. Liver is the main damaged organ.     

Production of Raw Starch-Saccharifying Thermostable and Neutral Glucoamylase by the Thermophilic Mold <Emphasis Type="Italic">Thermomucor indicae-seudaticae</Emphasis> in Submerged Fermentation

Among physical and nutritional parameters optimized by “one variable at a time” approach, four cultural variables (sucrose, MgSO₄ ^.7H₂O, inoculum size, and incubation period) significantly affected glucoamylase production. These variables were, therefore, selected for optimization using response surface methodology. The p-values of the coefficients for linear effect of sucrose and inoculum size were less than 0.0001, suggesting them to be the key experimental variables in glucoamylase production. The enzyme production (34 U/ml) attained under optimized conditions (sucrose, 2%; MgSO₄ ^.7H₂O, 0.13%; yeast extract, 0.1%; inoculum size, 5 × 10⁶ spores per 50 ml production medium; incubation time, 48 h; temperature, 40°C; and pH 7.0) was comparable with the value predicted by polynomial model (34.2 U/ml). An over all 3.1-fold higher enzyme titers were attained due to response surface optimization. The experimental model was validated by carrying out glucoamylase production in shake flasks of increasing capacity (0.25–2.0 l) and 22-l laboratory bioreactors (stirred tank and airlift), where the enzyme production was sustainable. Furthermore, the fermentation time was reduced from 48 h in shake flasks to 32 h in bioreactors.     

Freeze-drying for the stabilisation of shellfish toxins in mussel tissue (<Emphasis Type="Italic">Mytilus edulis</Emphasis>) reference materials

Two samples of mussels (Mytilus edulis) were collected from the southwest of Ireland. One sample contained domoic acid, the other sample contained okadaic acid, dinophysistoxin-2 and azaspiracid-1, -2 and -3. Wet and freeze-dried reference materials were prepared from each of the two samples to test for differences in homogeneity, stability and extractability of the analytes in either condition. Wet materials were homogenised, aliquoted and hermetically sealed under argon and subsequently frozen at −80 °C. Dry materials were similarly homogenised but frozen in flat cakes prior to freeze-drying. After grinding, sieving and further homogenisation, the resulting powder was aliquoted and hermetically sealed. Domoic acid materials were characterised using HPLC–UV, while LC–MS was used for the determination of lipophilic toxins. The extractabilities of all phycotoxins studied were comparable for wet and freeze-dried materials once a sonication step had been carried out for reconstitution of the freeze-dried materials prior to extraction. Homogeneity was assessed through replicate analysis of the phycotoxins (n = 10), and was found to be similar for wet and freeze-dried materials, for both hydrophilic and lipophilic toxins. Water contents were determined for both wet and freeze-dried materials, and particle size was determined for the freeze-dried materials. Stability was evaluated isochronously over eight months at four temperatures (−20, +4, +20 and +40 °C). The freeze-dried material containing domoic acid was stable over the whole duration at all temperatures, while in the wet material domoic acid degraded to some extent at all temperatures except −20 °C. In freeze-dried and wet materials containing lipophilic toxins, okadaic acid, dinophysistoxin-2, azaspiracid-1 and azaspiracid-2 were stable over the whole duration at all conditions, while concentrations of azaspiracid-3 changed significantly in both materials at some storage temperatures. Figure Aliquots of freeze-dried and wet mussel tissue reference materials containing the various shellfish toxins examined in the study     

Study on the cationic modification and dyeing of ramie fiber

A modification procedure for ramie fiber using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) as a cationic agent and NaOH as a catalyst was developed in this paper. The morphological and structural transformations of the fiber induced by modification were determined by XRD (XRD), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). XRD results show that the crystal structure of the modified fiber was still preserved although its crystallinity was decreased, which was confirmed from the TGA results. The mechanisms for the modification and dyeing of ramie fiber were analyzed, and the optimum modification conditions were determined to be the CHPTAC concentration of 30 g L⁻¹, the NaOH concentration of 15 g L⁻¹, the reaction temperature of 50 °C, and the reaction time of 60 min. The raw and the modified fibers were dyed with C.I. reactive red 2. The K/S values for the cationic modified fiber increased to be three times as high as the unmodified fiber. The dye uptakes increased greatly with an increase in the nitrogen contents up to 0.4% on the modified fibers.     

Investigation of polynuclear Zr(IV) hydroxide complexes by nanoelectrospray mass-spectrometry combined with XAFS

Polynuclear species of zirconium in acidic aqueous solution are investigated by combining X-ray absorption spectroscopy (XAFS) and nanoelectrospray mass spectrometry (ESI-MS). Species distributions are measured between pH_C 0 and pH_C 3 for [Zr] = 1.5–10 mM. While the monomer remains a minor species, with increasing pH the degree of polymerization increases and the formation of tetramers, pentamers, octamers, and larger polymers is observed. The high resolution of the mass spectrometer permits the unambiguous determination of polynuclear zirconium hydroxide complexes by means of their isotopic patterns. The relative abundances of mononuclear and polynuclear species present simultaneously in solution are measured, even if one of the species contributes only 0.1% of the Zr concentration. For the first time it has been directly observed that the hydrolysis of polynuclear Zr species is a continuous process which leads to charge compensation through the sequential substitution of water molecules by hydroxide ligands until doubly charged polymers dominate at conditions (H⁺ and Zr concentrations) close to the solubility of Zr(OH)₄(am). The invasiveness of the electrospray process was minimized by using very mild declustering conditions, leaving the polynuclear species within a solvent shell of approximately 20 water molecules. Figure Schematic Diagram of Multiplexed Measurement of 9 Anti-Nuclear Antibodies Using the AtheNa Multilyte Assay