Baicalin Released from <Emphasis Type=Italic>Scutellaria baicalensis</Emphasis> Induces Autotoxicity and Promotes Soilborn Pathogens

Experiments were conducted to determine whether allelochemicals released by the important medicinal plant Scutellaria baicalensis Georgi help to explain why S. baicalensis performs poorly when continuously cropped. Based on high performance liquid chromatography, the concentration of baicalin (the major compound released by S. baicalensis roots) in the soil where S. baicalensi had been grown for 3 years was 0.97 μg.g⁻¹. Both the crude extracts from S. baicalensis roots and purified baicalin at 0.97 μg.g⁻¹ increased the mortality of S. baicalensis seedlings in an autotoxicity test. This concentration stimulated the growth of two soilborne pathogens (Pythium ultimum and Rhizoctonia solani) on agar, and their growth and pathogenic activity in sand. Seedling mortality and damping-off caused by both pathogens were greater in sand where S. canadensis had previously grown than in sand where it had not previously grown. Mortality and damping-off of S. baicalensis seedlings also were significantly higher in soil collected from an S. baicalensis field than in soil collected from a Nicotiana tabacum L. field. The results are consistent with the hypothesis that allelochemicals released by S. baicalensis negatively affect S. baicalensis directly by inducing autotoxicity and indirectly by increasing pathogen activity in the soil.     

Journey in the <Emphasis Type=Italic>Ostrinia</Emphasis> World: From Pest to Model in Chemical Ecology

The European corn borer Ostrinia nubilalis (ECB; Lepidoptera: Crambidae) is a widely recognized pest of agricultural significance over much of the northern hemisphere. Because of the potential value of pheromone-based control, there has been considerable effort devoted to elucidation of the ECB chemical ecology. The species is polymorphic regarding its female-produced pheromone. Partly because of this feature, over the years the ECB has become a model to study pheromone evolution. This review should assist in identifying new areas of pheromone research by providing an overview of the literature produced on this subject for the ECB since the late 1960’s.     

Phase Equilibria of the Sn-Sb Binary System

Sn-Sb alloys are important high-temperature solders. However, inconsistencies are found in the available phase diagrams, and some phase boundaries in the Sn-Sb system have not been determined. Sn-Sb alloys were prepared, equilibrated at 160°C to 300°C, and the equilibrium phases and their compositions were determined. The β-SnSb phase has a very wide compositional homogeneity range, and its composition varies from Sn-47.0at.%Sb to Sn-62.8at.%Sb. There is no order–disorder transformation of the β-SnSb phase. There are three peritectic reactions in the Sn-Sb system, L + Sb = β-SnSb, L + β-SnSb = Sn₃Sb₂, and L + Sn₃Sb₂ = Sn, and their temperatures are 424°C, 323°C, and 243°C, respectively. Thermodynamic models of the Sn-Sb binary system were developed using the CALPHAD approach based on the experimental results of this study and the data in the literature. The calculated phase diagram and thermodynamic properties are in good agreement with the experimental determinations.     

Pheromones and Other Semiochemicals for Monitoring Rare and Endangered Species

As global biodiversity declines, biodiversity and conservation have become ever more important research topics. Research in chemical ecology for conservation purposes has not adapted to address this need. During the last 10–15 years, only a few insect pheromones have been developed for biodiversity and conservation studies, including the identification and application of pheromones specifically for population monitoring. These investigations, supplemented with our knowledge from decades of studying pest insects, demonstrate that monitoring with pheromones and other semiochemicals can be applied widely for conservation of rare and threatened insects. Here, I summarize ongoing conservation research, and outline potential applications of chemical ecology and pheromone-based monitoring to studies of insect biodiversity and conservation research. Such applications include monitoring of insect population dynamics and distribution changes, including delineation of current ranges, the tracking of range expansions and contractions, and determination of their underlying causes. Sensitive and selective monitoring systems can further elucidate the importance of insect dispersal and landscape movements for conservation. Pheromone-based monitoring of indicator species will also be useful in identifying biodiversity hotspots, and in characterizing general changes in biodiversity in response to landscape, climatic, or other environmental changes.     

Process Optimization,Physical Properties,and Environmental Stability of an α-Tocopherol Nanocapsule Preparation Using Complex Coacervation Method and Full Factorial Design

α-Tocopherol (α-Toc) has valuable biological activity, but its activity is limited when exposed to environmental factors. Nanocapsules can be used to overcome this problem. Using nanocapsules in the range of 100–200 nm is more beneficial. A 2⁴ full factorial design was carried out to optimize the size of nanocapsules using the complex coacervation method. The four factors were the amount of the wall material, the ratio of core material to wall material, the pH of the solution, and the speed of the homogenizer. The smallest nanocapsules (176 nm) were obtained at a wall content (gelatine and pectin) of 0.8 mg, a percentage of core material (α-Toc) to wall material of 20%, a pH = 4.5, and a homogenizer speed of 12,000 rpm. The encapsulation efficiency was 90.6 ± 1.1%, and the encapsulation yield was 83.4 ± 1.6%. Assessment of the stability of α-Toc after 1 month showed that encapsulation could improve its stability in the presence of three influential factors: humidity, light, and temperature.     

Elemental mercury removal from syngas at high-temperature using activated char pyrolyzed from biomass and lignite

Activated char obtained by the co-pyrolysis of a mixture of lignite and biomass impregnated with ZnCl₂ solution was found to be effective for the high-temperature capture of mercury from syngas. The prepared samples were characterized by X-ray photoelectron spectroscopy, Hg-thermal programmed desorption as well as Brunauer- Emmett-Teller analysis. The results show that activated char exhibits a large surface area as well as abundant micropores and C-Cl, C=O, and COOH functional groups. During the chemisorption of mercury, gaseous Hg⁰ is first oxidized by C-Cl to HgCl₂; HgCl₂ which acts as the intermediate product then reacts with the C=O and COOH functional groups on the surface of activated char to generate Hg-OM. At high adsorption temperatures, Hg-OM on the adsorbent surface can further decompose and generate HgO. The C-Cl group is important for the first oxidation step of gaseous Hg⁰, and the formation of HgCl₂ is the rate-determining step for the entire process of adsorption.     

Matrix based method for synthesis of main intensified and integrated distillation sequences

The objective of many studies in this area has involved access to a column-sequencing algorithm enabling designers and researchers alike to generate a wide range of sequences in a broad search space, and be as mathematically and as automated as possible for programing purposes and with good generality. In the present work an algorithm previously developed by the authors, called the matrix method, has been developed much further. The new version of the algorithm includes thermally coupled, thermodynamically equivalent, intensified, simultaneous heat and mass integrated and divided-wall column sequences which are of gross application and provide vast saving potential both on capital investment, operating costs and energy usage in industrial applications. To demonstrate the much wider searchable space now accessible, a three component separation has been thoroughly examined as a case study, always resulting in an integrated sequence being proposed as the optimum.