206 research outputs found
Racoleus, a new genus of sterile filamentous lichen-forming fungi from the tropics, with observations on the nomenclature and typification of Cystocoleus and Racodium
Racoleus trichophorus gen. sp. nov. is described for a tropical sterile filamentous lichenized fungus which overgrows various crustose lichens on bark. It shares some features with Cystocoleus and Racodium, but is unique in having non-lichenized long lateral spines. The genus, which is known from China, the Ivory Coast, and Peru, is of uncertain systematic position; on the basis of morphological similarities, however, it may be referred to â? Capnodiales (incertae sedis)â ad interim. In addition, the nomenclature and typification of the monotypic genera Cystocoleus and Racodium are reviewed, and lectotypes selected for the type of each. The available information on the ecology and distribution of these two genera is also summarized, and scanning electron micrographs (SEM) of all three species are presented for the first time
Sample Handling and Chemical Kinetics in an Acoustically Levitated Drop Microreactor
Accurate measurement of enzyme kinetics is an essential part of understanding the mechanisms of biochemical reactions. The typical means of studying such systems use stirred cuvettes, stopped-flow apparatus, microfluidic systems, or other small sample containers. These methods may prove to be problematic if reactants or products adsorb to or react with the containerâs surface. As an alternative approach, we have developed an acoustically-levitated drop reactor eventually intended to study enzyme-catalyzed reaction kinetics related to free radical and oxidative stress chemistry. Microliter-scale droplet generation, reactant introduction, maintenance, and fluid removal are all important aspects in conducting reactions in a levitated drop. A three capillary bundle system has been developed to address these needs. We report kinetic measurements for both luminol chemiluminescence and the reaction of pyruvate with nicotinamide adenine dinucleotide, catalyzed by lactate dehydrogenase, to demonstrate the feasibility of using a levitated drop in conjunction with the developed capillary sample handling system as a microreactor
Standing waves for acoustic levitation
Standing waves are the most popular method to achieve acoustic trapping. Particles with greater acoustic impedance than the propagation medium will be trapped at the pressure nodes of a standing wave. Acoustic trapping can be used to hold particles of various materials and sizes, without the need of a close-loop controlling system. Acoustic levitation is a helpful and versatile tool for biomaterials and chemistry, with applications in spectroscopy and lab-on-a-droplet procedures. In this chapter, multiple methods are presented to simulate the acoustic field generated by one or multiple emitters. From the acoustic field, models such as the Gor'kov potential or the Flux Integral are applied to calculate the force exerted on the levitated particles. The position and angle of the acoustic emitters play a fundamental role, thus we analyse commonly used configurations such as emitter and reflector, two opposed emitters, or arrangements using phased arrays
Rapid solidification of acoustically levitated Al-Cu-Si eutectic alloy under laser irradiation
The Effect of Salt on Protein Chemical Potential Determined by Ternary Diffusion in Aqueous Solutions
Simulation of harvester productivity in selective and boom-corridor thinning of young forests
Forest management practices may change in the future, due to increases in the extraction of forest fuel in first thinnings. Simulation models can be used to aid in developing new harvesting systems. We used such an approach to assess the productivity of innovative systems in various thinnings of young stands with wide ranges of mean breast height diameter (1.5â15.6 cm), stems per hectare (1000â19,100), and mean height (2.3â14.6 m).
The results show that selective multiple-tree-handling increases productivity by 20â46% compared to single-tree-handling. If the trees are cut in boom-corridors (10Ă1 or 2 m strips between strip roads), productivity increases up to 41%, compared to selective multiple-tree-handling. Moreover, if the trees are felled using area-based felling systems, productivity increases by 33â199%, compared to selective multiple-tree-handling. For any given harvesting intensity, productivity increased the most in the densest stands with small trees.
The results were used to derive time consumption functions. Comparisons with time study results suggest that our simulation model successfully mimicked productivity in real-life forest operations, hence the model and derived functions should be useful for cost calculations and evaluating forest management scenarios in diverse stands
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