Three-Dimensional Numerical Modeling of Acoustic Trapping in Glass Capillaries

Acoustic traps are used to capture and handle suspended microparticles and cells in microfluidic applications. A particular simple and much-used acoustic trap consists of a commercially available, millimeter-sized, liquid-filled glass capillary actuated by a piezoelectric transducer. Here, we present a three-dimensional numerical model of the acoustic pressure field in the liquid coupled to the displacement field of the glass wall, taking into account mixed standing and traveling waves as well as absorption. The model predicts resonance modes well suited for acoustic trapping, their frequencies and quality factors, the magnitude of the acoustic radiation force on a single test particle as a function of position, and the resulting acoustic retention force of the trap. We show that the model predictions are in agreement with published experimental results, and we discuss how improved and more stable acoustic trapping modes might be obtained using the model as a design tool.Comment: 13 pages, 15 pdf figures, pdfLatex/Revte

Spatially and Intertemporally Efficient Waste Management: The Costs of Interstate Flow Control

We examine the intertemporal allocation of the solid waste of cities within the United States to spatially distributed landfills and incinerators, taking into account that capacity at existing and potential landfills is scarce. Amendments have been proposed to restrict waste flows between states by means of quotas and surcharges. We assess the aggregate surplus loss (and its regional distribution) resulting from proposed policies. In addition, we find that limitations on the size of shipments to any one state can have the perverse effect of substantially increasing interstate waste shipments as states export smaller volumes to more destinations.Solid Waste, Efficiency, Hotelling

Spatial Variability and Error Limits of Reference Evapotranspiration Estimates

The overall objective of this research was to develop a methodology for assessing the spatial variability and error limits of reference evapotranspiration (ETr) estimates from a weather station network. Likely errors introduced into ETr estimates due to sensor measurement variability and nonstandard site conditions were investigated. Temporal and spatial correlation structures of the weather variables used to compute ETr and of ETr data collected over a three-year period by an operational agricultural weather station network were studied. Results indicated that ETr errors are minimal compared to inherent model error when sensors (of the type studied) are maintained and calibrated to operate with measurement errors that are within the limits of manufacturer\u27s specifications of accuracy. Sensor evaluation studies showed new and recalibrated/reconditioned sensors often were operating within the limits of accuracy specifications. A methodology for adjusting maximum, minimum, and dewpoint temperature data collected at arid weather measurement sites to reflect the conditions of an irrigated measurement site was developed. Positive bias in air temperatures and negative bias in dewpoint temperatures measured at arid sites resulted in positive bias in ETr. as much as 17% greater (approximately 1.4 mm d-1) in July and August, at some arid sites as compared to an irrigated reference site. Weather data adjustment algorithms based on daily energy and soil water balances at the dry sites were developed. These provided effective removal of bias in the dry station data and ETr estimates. Univariate autoregressive models of daily weather parameters--maximum and minimum temperature, solar radiation, dewpoint temperature and wind speed, and daily ETr--were developed using standard time series analysis approaches. These models can be used to forecast/estimate weather variables or ETr at the weather station sites studied. Space-time models were developed for each variable as multivariate AA(1) processes, having lag one temporal correlation and lag zero and lag one spatial correlation. The lag zero cross correlation matrixes of standardized zero-mean, and spatially and seasonally detrended residuals of each variable were analyzed with interstation distances and with contoured isoline plots imposed on the network area. This revealed that geographically nearest neighbor stations were not always the most correlated. Interpolation of observations between and among network sites should include consideration of spatial correlation structure as well as physical proximity. The multivariate AR(1) models were used in state-space representation with the Kalman filter to determine statistically optimal estimates of the true state of a network variable at a given time. The effects of maximum and minimum weather data measurement errors found during the course of this research were evaluated in the Kalman filter. Kalman filter ETr estimation error was equivalent to the reported error of the Penman-Wright ETr model. The Kalman filter was shown to be an effective spatial interpolation technique for ETr. Using stations that were best correlated to a suppressed fictitious point interpolation site was more efficient than using stations that were geographically closest, i.e., only three best correlated stations provided the same ETr estimation error as was obtained using six nearest neighbors

Quantum-state input-output relations for absorbing cavities

The quantized electromagnetic field inside and outside an absorbing high-$Q$ cavity is studied, with special emphasis on the absorption losses in the coupling mirror and their influence on the outgoing field. Generalized operator input-output relations are derived, which are used to calculate the Wigner function of the outgoing field. To illustrate the theory, the preparation of the outgoing field in a Schr\"{o}dinger cat-like state is discussed.Comment: 12 pages, 5 eps figure

TPL-2 restricts Ccl24-dependent immunity to Heligmosomoides polygyrus

Funding: This work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001220), the UK Medical Research Council (FC001220), and the Wellcome Trust (FC001200). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We are indebted to The Francis Crick Institute Flow Cytometry facility, and in particular Bhavik Patel, Graham Preece, Wayne Turnbull and Phil Hobson. We would also like to thank The Francis Crick Institute Procedural Service Section for production of GA lines and Biological Services, especially Trisha Norton, Keith Williams and Adebambo Adekoya for animal husbandry and technical support; to Riccardo Guidi for constructive discussions and technical assistance. We would like to thank Gitta Stockinger and AhR Immunity Laboratory for providing technical support and reagents throughout this study. We also thank Richard Rance and the Wellcome Trust Sanger Institute’s 454 pyrosequencing team for generating 16S rRNA gene data.Peer reviewedPublisher PD

Developmental refinement of cortical systems for speech and voice processing

Development typically leads to optimized and adaptive neural mechanisms for the processing of voice and speech. In this fMRI study we investigated how this adaptive processing reaches its mature efficiency by examining the effects of task, age and phonological skills on cortical responses to voice and speech in children (8-9years), adolescents (14-15years) and adults. Participants listened to vowels (/a/, /i/, /u/) spoken by different speakers (boy, girl, man) and performed delayed-match-to-sample tasks on vowel and speaker identity. Across age groups, similar behavioral accuracy and comparable sound evoked auditory cortical fMRI responses were observed. Analysis of task-related modulations indicated a developmental enhancement of responses in the (right) superior temporal cortex during the processing of speaker information. This effect was most evident through an analysis based on individually determined voice sensitive regions. Analysis of age effects indicated that the recruitment of regions in the temporal-parietal cortex and posterior cingulate/cingulate gyrus decreased with development. Beyond age-related changes, the strength of speech-evoked activity in left posterior and right middle superior temporal regions significantly scaled with individual differences in phonological skills. Together, these findings suggest a prolonged development of the cortical functional network for speech and voice processing. This development includes a progressive refinement of the neural mechanisms for the selection and analysis of auditory information relevant to the ongoing behavioral task

The reaction 2H(p,pp)n in three kinematical configurations at E_p = 16 MeV

We measured the cross sections of the $^2$H(p,pp)n breakup reaction at E$_p$=16 MeV in three kinematical configurations: the np final-state interaction (FSI), the co-planar star (CST), and an intermediate-star (IST) geometry. The cross sections are compared with theoretical predictions based on the CD Bonn potential alone and combined with the updated 2$\pi$-exchange Tucson-Melbourne three-nucleon force (TM99'), calculated without inclusion of the Coulomb interaction. The resulting excellent agreement between data and pure CD Bonn predictions in the FSI testifies to the smallness of three-nucleon force (3NF) effects as well as the insignificance of the Coulomb force for this particular configuration and energy. The CST also agrees well whereas the IST results show small deviations between measurements and theory seen before in the pd breakup space-star geometries which point to possible Coulomb effects. An additional comparison with EFT predictions (without 3NF) up to order N$^3$LO shows excellent agreement in the FSI case and a rather similar agreement as for CD Bonn in the CST and IST situations.Comment: 20 pages, 11 figure

Total synthesis and biological evaluation of the tetramic acid based natural product harzianic acid and its stereoisomers

Financial support for this project was provided by Cancer Research UK (Grant No. C21383/A6950)The bioactive natural product harzianic acid was prepared for the first time in just six steps (longest linear sequence) with an overall yield of 22%. The identification of conditions to telescope amide bond formation and a Lacey-Dieckmann reaction into one pot proved important. The three stereoisomers of harzianic acid were also prepared, providing material for comparison of their biological activity. While all of the isomers promoted root growth, improved antifungal activity was unexpectedly associated with isomers in the enantiomeric series opposite that of harzianic acid.Publisher PDFPeer reviewe

Aggregation of Lipid Rafts Accompanies Signaling via the T Cell Antigen Receptor

The role of lipid rafts in T cell antigen receptor (TCR) signaling was investigated using fluorescence microscopy. Lipid rafts labeled with cholera toxin B subunit (CT-B) and cross-linked into patches displayed characteristics of rafts isolated biochemically, including detergent resistance and colocalization with raft-associated proteins. LCK, LAT, and the TCR all colocalized with lipid patches, although TCR association was sensitive to nonionic detergent. Aggregation of the TCR by anti-CD3 mAb cross-linking also caused coaggregation of raft-associated proteins. However, the protein tyrosine phosphatase CD45 did not colocalize to either CT-B or CD3 patches. Cross-linking of either CD3 or CT-B strongly induced tyrosine phosphorylation and recruitment of a ZAP-70(SH2)2–green fluorescent protein (GFP) fusion protein to the lipid patches. Also, CT-B patching induced signaling events analagous to TCR stimulation, with the same dependence on expression of key TCR signaling molecules. Targeting of LCK to rafts was necessary for these events, as a nonraft- associated transmembrane LCK chimera, which did not colocalize with TCR patches, could not reconstitute CT-B–induced signaling. Thus, our results indicate a mechanism whereby TCR engagement promotes aggregation of lipid rafts, which facilitates colocalization of LCK, LAT, and the TCR whilst excluding CD45, thereby triggering protein tyrosine phosphorylation