Portable, rapid, cost effective and simple analytical tools are in increasing demand to facilitate the routine monitoring of target chemical/biological compounds at the point-of-need. Such devices are highly relevant within the context of food safety, particularly concerning the screening of highly toxic and strictly regulated mycotoxins. To achieve ultrarapid detection of mycotoxins, namely aflatoxin B1, ochratoxin A and deoxynivalenol, at the point-of-need, a novel multiplexed bead-based microfluidic competitive immunosensor, coupled with an array of a-Si:H thin-film photodiodes for integrated fluorescence signal acquisition, is reported. Simultaneously measuring the initial binding rate for each analyte of the sample under analysis against an internal reference, this device provided limits of detection below 1 ng mL-1 for all mycotoxins in a single-step assay and within 1 minute after mixing the sample under analysis with a fluorescent conjugate. The compatibility of the device with the analysis of mycotoxins spiked in corn samples was further demonstrated after performing a sample preparation procedure based on aqueous two-phase extraction. The short times of analysis and sensitivities in the low ng mL-1 range make these devices potentially competitive with the lateral flow devices that are currently the standard for this application. Furthermore, this device architecture and concept is amenable of being expanded to other analytes in food safety, biomedical and other applications.
Colorectal cancer is the second leading cause of cancer death worldwide. Significant advances in the molecular mechanisms underlying colorectal cancer have been made; however, the clinical approval of new drugs faces many challenges. Drug discovery is a lengthy process causing a rapid increase in global health care costs. Patient-derived tumour organoids are considered preclinical models with the potential for preclinical drug screening, prediction of patient outcomes, and guiding optimized therapy strategies at an individual level. Combining microfluidic technology with 3D tumour organoid models to recapitulate tumour organization and in vivo functions led to the development of an appropriate preclinical tumour model, organoid-on-a-chip, paving the way for personalized cancer medicine. Herein, a low-cost microfluidic device suitable for culturing and expanding organoids, OrganoidChip, was developed. Patient-derived colorectal cancer organoids were cultured within OrganoidChip, and their viability and proliferative activity increased significantly. No significant differences were verified in the organoids’ response to 5-fluorouracil (5-FU) treatment on-chip and on-plate. However, the culture within the OrganoidChip led to a significant increase in colorectal cancer organoid-forming efficiency and overall size compared with conventional culture on a 24-well plate. Interestingly, early-stage and late-stage organoids were predominantly observed on-plate and within the OrganoidChip, respectively. The OrganoidChip thus has the potential to generate in vivo-like organotypic structures for disease modelling and drug screening applications.
A search is presented for same-sign top-quark production and down-type heavy quarks of charge −1/3 in events with two isolated leptons (e or µ) that have the same electric charge, at least two jets and large missing transverse momentum. The data are selected from pp collisions at √ s = 7 TeV recorded by the ATLAS detector and correspond to an integrated luminosity of 1.04 fb −1 . The observed data are consistent with expectations from Standard Model processes. Upper limits are set at 95% confidence level on the cross section of new sources of same-sign top-quark pair production of 1.4-2.0 pb depending on the assumed mediator mass. Upper limits are also set on the pair-production cross-section for new heavy down-type quarks; a lower limit of 450 GeV is set at 95% confidence level on the mass of heavy down-type quarks under the assumption that they decay 100% of the time to W t.
Keywords: Hadron-Hadron ScatteringOpen Access, Copyright CERN, for the benefit of the ATLAS collaboration
Conclusion 19The ATLAS collaboration 24
IntroductionThe Standard Model (SM) of the electroweak and strong interactions is extremely successful in explaining most of the measurements in particle physics at energies accessible today. Its predicted behaviour at high energies, however, presents some theoretical problems which have motivated a large variety of theories encompassing and extending it. Due to the large variety of models proposed, signature-based searches are often useful when exploring the consequences of these theories in an economical way. In hadron collisions it is useful to group final states by the number of charged leptons (electrons or muons). Within this classification, a signal with two leptons of the same electric charge (same-sign leptons) is Figure 1. Production of same-sign top-quark pairs via the production of a heavy vector boson (such as color-triplet Q interesting since it has a low background rate in the Standard Model, and potentially large contributions from new theories, for example new flavour-changing Z ′ bosons, proposed [1] to explain the forward-backward asymmetry (A FB ) measured at the Tevatron [2, 3], or new heavy quarks [4,5]. In this paper we present a search for events characterised by two isolated same-sign leptons in association with at least two jets and large missing transverse momentum (E miss T ). Two specific signal processes are considered, same-sign top-quark production [6][7][8] and pair production of down-type heavy quarks of charge −1/3 [9]. Feynman diagrams of these processes are shown in figures 1 and 2, respectively. The uu → tt process illustrated in figure 1 can be mediated at the tree level by the exchange of a s-channel resonance (left), or a t-channel resonance (right). In the case of new vector bosons exchanged in the s-channel, the new particle must be a colour-triplet or colour-sextet (respectively labelled as Q 5 µ , Y 5 µ ) with charge 4/3, while for t-channel exchange it can be a colour-singlet Z ′ or colour-octet g ′ , both with zero charge. For resonance m...
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