An integrated microfluidic system for reaction, high-sensitivity detection, and sorting of fluorescent cells and particles

Presented is a novel approach for an integrated micro total analysis system (microTAS) based on a microfluidic on-chip device that supports ultrasensitive confocal detection of fluorescent cells and particles and subsequently allows for their precise sorting in the fluid phase with respect to spectroscopic properties, such as brightness and color. The hybrid silicone elastomer/glass chip first comprises a branched channel system to initiate fluid mixing and to hydrodynamically focus the sample solution down to a thin flow layer, matching the size of the confocal detection volume placed at that position and, thus, providing a high detection efficiency. In the subsequent on-chip module, the dispersed cells or particles can be sorted into two different output channels. The sorting process is realized by a perpendicular deflection stream that can be switched electrokinetically. The performance of the automated sorting routine is demonstrated by precise partition of a mixture of differently colored fluorescent beads. Moreover, the specifically branched channel geometry allows for direct implementation of reaction steps prior to detection and sorting, which is demonstrated by inducing a selective recognition reaction between the fluorescent protein R-phycoerythrin and a mixture of live bacterial cells exhibiting or lacking the respective surface antigens.     

Accent Patterning on Domain-Related Information in Swedish Travel Dialogues

Investigation of travel-domain dialogues reveals travel-agent (System) utterances with intonational contours characterized by late-timed focal accents on given information. These accents occur on content words in utterance-initial position. The accentuation can be assumed to be related to the interactive nature of the dialogue in which the travel agent links back to a domain-related concept introduced by the client (User) and comments on it in an engaged manner. A perception test using constructed human-machine dialogues in which the machine (synthesized) responses vary as to the type of accent pattern on the initial words was developed to test listeners' preference for accent type. Results indicate that i) focal accents on domain-related utterance-initial given concepts are indeed preferred to nonfocal accents and that ii) late-timed focal accents are preferred to early-timed focal accents. These results have implications for the design of the prosody-generating component of human-machine dialogue systems.     

Improving the accuracy of decision tree induction by feature preselection

Selecting the right set of features for classification is one of the most important problems in designing a good classifier. Decision tree induction algorithms such as C4.5 have incorporated in their learning phase an automatic feature selection strategy, while some other statistical classification algorithms require the feature subset to be selected in a preprocessing phase. It is well known that correlated and irrelevant features may degrade the performance of the C4.5 algorithm. In our study, we evaluated the influence of feature preselection on the prediction accuracy of C4.5 using a real-world data set. We observed that accuracy of the C4.5 classifier could be improved with an appropriate feature preselection phase for the learning algorithm. Beyond that, the number of features used for classification can be reduced, which is important for image interpretation tasks since feature calculation is a time-consuming process.     

Remote monitoring of aerosols with ocean colour sensors: then and now

Synoptic coverage of the temporal and spatial variability of aerosol distribution patterns can only be achieved with satellites. Results from the first ocean colour sensor, the Coastal Zone Color Scanner (CZCS), indicate an annual cycle of the major mineral aerosol plumes that is consistent with the published literature. Seasonality and interannual aerosol variability observed with the CZCS agrees well with that found by ground data measurements and other satellite platforms used to monitor aerosols. The successor to the CZCS—the Sea viewing Wide Field of view Sensor (SeaWiFS)—provides estimates of aerosol load and particle size, both on a global scale. Seasonal maps of both of these aerosol optical properties are in accord with well-known distribution patterns and also with independent satellite estimates. These results indicate that ocean colour sensors are capable of monitoring the variability of global aerosol loads and, more recently, with the retrieval of aerosol particle size, they can be used to characterize different aerosol events.     

Terrestrial laser scanning for estimating urban tree volume and carbon content

The acquisition of single-tree-related information is an important task, especially in urban areas where there is an increasing interest in standing carbon stock. Therefore, an easy and robust method was developed to extract the volume, diameter at breast height (DBH) and height of single trees from point clouds of terrestrial laser scanning. For data acquisition, nine trees were scanned from several positions and the resulting high-resolution point clouds (20–60 million points) were analysed by an algorithm based on voxel structure. First, noise reduction was carried out, followed by filling of voxels inside the stem and branches through the intersection of four orthogonal viewing directions. After the elimination of erroneously generated fillings, volume was determined layer-wise for each cross section. For quality assessment, nine deciduous trees were selected, cut, weighed and analysed for wet specific gravity and carbon content in order to provide a control value. The estimated volumes agree with the control value within a range of –5.1% to +14.3%. This is also the case with DBH values; however, heights are systematically underestimated.     

A Study of the Properties of Compacts from Silicified Microcrystalline Celluloses

ABSTRACT

The paper deals with a study of tensile strength and disintegration time of compacts made from silicified microcrystalline celluloses, Prosolv SMCC 90, and Prosolv HD 90, in dependence on compression force, addition of two types of lubricants, and two active ingredients. The lubricants were magnesium stearate and sodium stearyl fumarate in a concentration of 0.5%, the active ingredients being ascorbic acid and acetylsalicylic acid in a concentration of 50%.

Prosolv SMCC 90 proved to be better compatible than Prosolv HD 90; the compacts were of higher strength, which was markedly increased with increasing compression force. Prosolv HD 90 was more sensitive to additions of lubricants, and a greater decrease in strength was recorded due to the influence of sodium stearyl fumarate. The effect of lubricants on the strength of compacts in the presence of active ingredients was not identical. The disintegration time of compacts from Prosolv HD 90 without as well as with lubricants was shorter than from Prosolv SMCC 90 and was increasing with increasing compression force. Disintegration time was increased with added lubricants, and it was markedly shortened by addition of active ingredients. Compacts containing ascorbic acid possessed a shorter disintegration time than those containing acetylsalicylic acid, and it was not markedly influenced by the presence of lubricants.     

The influence of discharge time on post-partial discharge gassing of zinc powder

Gas evolution in primary alkaline cells depends on discharge time. This dependence can be so strong that acceptable volumes of gas are evolved in cells when discharged over relatively long periods, whereas shorter times may lead to gassing beyond the limits of the cell design. The dependency of gassing on discharge time was investigated for a number of commercial cells and for different zinc-alloy powders. An indication of a relation between certain alloying elements and the gas evolution at short discharge times was found. The most important result of the investigations, however, was the development of a modified zinc powder production process which leads to zinc powders with reduced gas evolution rates for both short and long discharge times.