2,086 research outputs found
Hydrogel-Based Colorimetric Assay for Multiplexed MicroRNA Detection in a Microfluidic Device
Although microRNA (miRNA) expression levels provide important information regarding disease states owing to their unique dysregulation patterns in tissues, translation of miRNA diagnostics into point-of-care (POC) settings has been limited by practical challenges. Her; we developed a hydrogel-based microfluidic platform for colorimetric profiling of miRNAs, without the use of complex external equipment for fluidics and imaging. For sensitive and reliable measurement without the risk of sequence bias, we employed a gold deposition-based signal amplification scheme and dark-field imaging, and seamlessly integrated a previously developed miRNA assay scheme into this platform. The assay demonstrated a limit of detection of 260 fM, along with multiplexing of small panels of miRNAs in healthy and cancer samples. We anticipate this versatile platform to facilitate a broad range of POC profiling of miRNAs in cancer-associated dysregulation with high-confidence by exploiting the unique features of hydrogel substrate in an on-chip format and colorimetric analysis
A single mutation in the envelope protein modulates flavivirus antigenicity, stability, and pathogenesis
The structural flexibility or 'breathing' of the envelope (E) protein of flaviviruses allows virions to sample an ensemble of conformations at equilibrium. The molecular basis and functional consequences of virus conformational dynamics are poorly understood. Here, we identified a single mutation at residue 198 (T198F) of the West Nile virus (WNV) E protein domain I-II hinge that regulates virus breathing. The T198F mutation resulted in a ~70-fold increase in sensitivity to neutralization by a monoclonal antibody targeting a cryptic epitope in the fusion loop. Increased exposure of this otherwise poorly accessible fusion loop epitope was accompanied by reduced virus stability in solution at physiological temperatures. Introduction of a mutation at the analogous residue of dengue virus (DENV), but not Zika virus (ZIKV), E protein also increased accessibility of the cryptic fusion loop epitope and decreased virus stability in solution, suggesting that this residue modulates the structural ensembles sampled by distinct flaviviruses at equilibrium in a context dependent manner. Although the T198F mutation did not substantially impair WNV growth kinetics in vitro, studies in mice revealed attenuation of WNV T198F infection. Overall, our study provides insight into the molecular basis and the in vitro and in vivo consequences of flavivirus breathing
The Bell Laboratories (13)CO Survey: Longitude-Velocity Maps
A survey is presented of the Galactic plane in the J=1-0 transition of
(13)CO. About 73,000 spectra were obtained with the 7 m telescope at Bell
Laboratories over a ten-year period. The coverage of survey is (l, b) = (-5 to
117, -1 to +1), or 244 square degrees, with a grid spacing of 3' for |b| < 0.5,
and a grid spacing of 6' for |b| > 0.5. The data presented here have been
resampled onto a 3' grid. For 0.68 km/s channels, the rms noise level of the
survey is 0.1 K on the scale. The raw data have been transformed into
FITS format, and all the reduction processes, such as correcting for emission
in the reference positions, baseline removal and interpolation were conducted
within IRAF using the FCRAO task package and additional programs. The reduced
data are presented here in the form of longitude-velocity color maps at each
latitude. These data allow identification and classification of molecular
clouds with masses in excess of ~ 1,000 solar masses throughout the first
quadrant of the Galaxy. Spiral structure is manifested by the locations of the
largest and brightest molecular clouds.Comment: 23 pages, 7 figures, ApJS submitted (out of 41 frames of Figure4,
only one is included becaue of size limit
Activity-dependent trafficking of lysosomes in dendrites and dendritic spines.
In neurons, lysosomes, which degrade membrane and cytoplasmic components, are thought to primarily reside in somatic and axonal compartments, but there is little understanding of their distribution and function in dendrites. Here, we used conventional and two-photon imaging and electron microscopy to show that lysosomes traffic bidirectionally in dendrites and are present in dendritic spines. We find that lysosome inhibition alters their mobility and also decreases dendritic spine number. Furthermore, perturbing microtubule and actin cytoskeletal dynamics has an inverse relationship on the distribution and motility of lysosomes in dendrites. We also find trafficking of lysosomes is correlated with synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors. Strikingly, lysosomes traffic to dendritic spines in an activity-dependent manner and can be recruited to individual spines in response to local activation. These data indicate the position of lysosomes is regulated by synaptic activity and thus plays an instructive role in the turnover of synaptic membrane proteins
FK506 suppression of heart and liver allograft rejection: II: The induction of graft acceptance in rats
Lewis recipients of orthotopic ACI livers had permanent graft acceptance induced with 3 doses of i.m. FK506 in the early postoperative period. They were studied 100 and 300 days posttransplantation. The re-cipients rejected ACI as well as Brown Norway (BN) (third-party) skin grafts, and had lymphocytes with substantial reactivity by mixed lymphocyte culture testing against ACI and third-party (BN) alloantigens. Lymphocyte subset redistribution had not occurred in the peripheral blood or spleens of these animals, and there was no evidence of Suppressor cell activation by in vitro and in vivo tests. Graft-versus-host reactivity in splenic lymphoid tissues of these recipients was demonstrated with the popliteal lymph node assay. Attempts at adaptive transfer with recipient lymphocytes were unsuccessful. Heart graft acceptance was far more difficult to accomplish than liver graft acceptance, and probably was never permanent. ACI heart graft Prolongation in LEW recipients after a brief induction with FK506 lasted for no more than 3 months in most animals. The temporary heart graft acceptance was specific for hearts of the original ACI donor strain but not for ACI skin. Results of studies of lymphocyte subsets and suppressor cell activity were similar to those in the liver recipients. These studies illustrate how poorly graft acceptance is understood and how badly further work is needed to clarify its mechanism. © 1990 by Williams & Wilkins
Die Computertomographie bei der Bildgebung von Kindern mit kongenitalen Herzvitien
Zusammenfassung: Kongenitale Herzfehler sind die häufigsten kongenitalen Fehlbildungen. Echokardiographie und Katheterangiographie gelten allgemein als Goldstandard zur Abklärung angeborener Herzerkrankungen. Die Magnetresonanztomographie ist aufgrund ihrer Fähigkeit, Herzvitien morphologisch und funktionell zu charakterisieren, als ein wichtiges ergänzendes Verfahren anzusehen. Durch mehr und mehr dosissparende Untersuchungsprotokolle der neuesten Gerätegenerationen und eine gleichzeitig bessere zeitliche und räumliche Auflösung findet die Computertomographie zunehmend Eingang in die Abklärung kongenitaler Herzfehler. In der präoperativen Planung und der postoperativen Kontrolle erlaubt sie eine übersichtliche Darstellung komplexer Fehlbildung nicht nur des Herzens, sondern auch der pulmonalvenösen und -arteriellen Zirkulation sowie des systemischen Kreislaufs. Dieser Beitrag gibt eine Übersicht über die technischen Aspekte der kardialen CT und die Anpassung des Untersuchungsprotokolls an die zu erwartende Pathologie und das Alter des Kindes. Zudem werden die Möglichkeiten und Limitationen der unterschiedlichen dosissparenden Protokolle erläuter
Lattice instabilities of cubic NiTi from first principles
The phonon dispersion relation of NiTi in the simple cubic B2 structure is
computed using first-principles density-functional perturbation theory with
pseudopotentials and a plane-wave basis set. Lattice instabilities are observed
to occur across nearly the entire Brillouin zone, excluding three
interpenetrating tubes of stability along the (001) directions and small
spheres of stability centered at R. The strongest instability is that of the
doubly degenerate M5' mode. The atomic displacements of one of the eigenvectors
of this mode generate a good approximation to the observed B19' ground-state
structure.Comment: 11 pages, 3 figure
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