1,147 research outputs found
Spatial and Temporal Immune Response in House Flies in Response to Ingestion of Bacillus Cereus and Eschericha Coli 0157-H7
House flies (Musca domestica L.) feed and breed on septic substrates, putting them in direct contact with a multitude of disease causing agents and can act as a bridge for those agents to humans. The house fly has previously been shown to carry many different species of bacteria that are pathogenic. Escherichia coli O157:H7 is a pathogenic enterohemorrhagic serotype of E. coli that can be vectored by the house fly. Bacillus cereus is a foodborne pathogen that has also been isolated from the house fly in previous studies. To examine vector potential for these pathogens, house flies were fed green fluorescent protein (GFP)-expressing E. coli 157:H7 or B. cereus and then bacterial fate and localization of fly defensive responses were analyzed at various hours post-ingestion (h PI). Bacterial fate was assessed qualitatively by localizing bacteria via microscopy and quantitatively by culturing whole fly homogenate. House fly defensive responses, including three antimicrobial peptides (AMPs; Defensin, Diptericin, and Cecropin) and the peptidoglycan cleaving enzyme Lysozyme, were analyzed using immunofluorescent localization. Localization of B. cereus and E. coli O157:H7 at various time points correlated with evidence of lysed bacteria in microscopy, a decrease in recovered bacteria, and observed expression of AMPs and Lysozyme. Bacterial recovery showed that B. cereus decreased steadily up to 24 h PI and E. coli O157:H7 decreased steadily up to 12 h PI. Flies fed B. cereus induced Defensin, Diptericin, and Lysozyme expression that peaked in the midgut at 6 h PI. In contrast, flies fed E. coli O157:H7 showed noticeable expression of only Lysozyme and Diptericin at 2 and 6 h PI in the midgut and proventriculus. This study shows that B. cereus elicits a strong immune response from the house fly and can persist in the gut until 24 h PI, while E. coli O157:H7 elicits little immune response and can persist up to 12 h PI. These findings help to define whether or not pathogenic bacteria can survive at infectious levels within the fly, how the house fly responds to ingestion of these pathogens, and finally how long the bacteria can persist within the fly
Advances in the molecular classification of pediatric brain tumors: a guide to the galaxy
Central nervous system (CNS) tumors are the most common solid tumor in pediatrics, accounting for approximately 25% of all childhood cancers, and the second most common pediatric malignancy after leukemia. CNS tumors can be associated with significant morbidity, even those classified as low grade. Mortality from CNS tumors is disproportionately high compared to other childhood malignancies, although surgery, radiation, and chemotherapy have improved outcomes in these patients over the last few decades. Current therapeutic strategies lead to a high risk of side effects, especially in young children. Pediatric brain tumor survivors have unique sequelae compared to age-matched patients who survived other malignancies. They are at greater risk of significant impairment in cognitive, neurological, endocrine, social, and emotional domains, depending on the location and type of the CNS tumor. Next-generation genomics have shed light on the broad molecular heterogeneity of pediatric brain tumors and have identified important genes and signaling pathways that serve to drive tumor proliferation. This insight has impacted the research field by providing potential therapeutic targets for these diseases. In this review, we highlight recent progress in understanding the molecular basis of common pediatric brain tumors, specifically low-grade glioma, high-grade glioma, ependymoma, embryonal tumors, and atypical teratoid/rhabdoid tumor (ATRT). © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd
The Resummed Photon Spectrum in Radiative Upsilon Decays
We present a theoretical prediction for the photon spectrum in radiative
Upsilon decay including the effects of resumming the endpoint region, E_\gamma
-> M_\Upsilon/2. Our approach is based on NRQCD and the soft collinear
effective theory. We find that our results give much better agreement with data
than the leading order NRQCD prediction.Comment: 4 pages, 6 figure
Resummation of Large Endpoint Corrections to Color-Octet J/psi Photoproduction
An unresolved problem in J/psi phenomenology is a systematic understanding of
the differential photoproduction cross section, dsigma/dz [gamma + p -> J/psi +
X], where z= E_psi/E_gamma in the proton rest frame. In the non-relativistic
QCD (NRQCD) factorization formalism, fixed-order perturbative calculations of
color-octet mechanisms suffer from large perturbative and nonperturbative
corrections that grow rapidly in the endpoint region, z -> 1. In this paper,
NRQCD and soft collinear effective theory are combined to resum these large
corrections to the color-octet photoproduction cross section. We derive a
factorization theorem for the endpoint differential cross section involving the
parton distribution function and the color-octet J/psi shape functions. A one
loop matching calculation explicitly confirms our factorization theorem at
next-to-leading order. Large perturbative corrections are resummed using the
renormalization group. The calculation of the color-octet contribution to
dsigma/dz is in qualitative agreement with data. Quantitative tests of the
universality of color-octet matrix elements require improved knowledge of shape
functions entering these calculations as well as resummation of the
color-singlet contribution which accounts for much of the total cross section
and also peaks near the endpoint.Comment: 30 pages, 6 figure
Duration of Outpatient Antibiotic Therapy for Common Outpatient Infections, 2017.
Our objective was to describe the duration of antibiotic therapy for the management of common outpatient conditions. The median duration of antibiotic courses for most common conditions, except for acute cystitis, was 10 days, in many cases exceeding guideline-recommended durations
Linear and nonlinear optical properties of silica aerogel
Scattering media have traditionally been seen as a hindrance to the controlled transport of
light through media, creating the familiar speckle pattern. However such matter does not cause
the loss of information but instead performs a highly complex deterministic operation on the
incoming flux. Through sculpting the properties of the incoming wavefront, we can unlock the
hidden characteristics of these media, affording us far more degrees of freedom than that which is
available to us in traditional ballistic optics.
These additional degrees of freedom have allowed for the creation of compact sophisticated
optical devices based only on the deterministic nature of light scattering. Such devices include
diffraction-limit-beating lenses, polarimeters, spectrometers, and some which can transmit entire
images through a scattering substance.
Additional degrees of freedom would allow for the creation of even more powerful devices,
in new working regimes. In particular, the application of related techniques where the scattering
material is actively modified is limited.
This thesis is concerned with the use of optothermal nonlinearity in random media as a way to
provide an additional degree of control over light which scatters through it. Specifically, we are
concerned with silica aerogel as a platform for this study.
Silica aerogel is a lightweight skeletal structure of silica fibrils, which results in a material which
is up to 99.98 % by volume. This material exhibits a unique cocktail of properties of use such as near
unitary refractive index, an order of magnitude lower thermal conductivity, and high optothermal
nonlinearity. The latter two of these properties allow for the creation of localised steep thermal
gradients, proportionally affecting the low refractive index significantly. Additionally through
differing fabrication steps, the opacity, and as a result, we can adjust the scattering strength.
In line with the development of light deterministic light scattering techniques in linear media,
we develop through the use of pump-probe setups, a framework for the development of a similar
line of techniques in nonlinear scattering media. We show that we can reversibly control the
far-field propagation of light in weakly scattering silica aerogel. Following this, we show that
nonlinear perturbation can be used to extend and modify the optical memory effect, where slight
adjustments in scattering direction maintain the overall correlation of the scattered profile. Finally,
we measure the nonlinear transmission matrix, a complete description of how any wavefront would
pass through at a particular point in a scattering media, and how that scattering can be modified
through the application of an optothermal nonlinearity.
Extending the tool of scattering media into the nonlinear regime helps pave the way toward the
next set of advances in the field of light scattering control."This work was supported by the Engineering and Physical Sciences Research Council [grant number
EP/M508214/1]" -- Fundin
Exclusive Radiative Decays of Upsilon in SCET
We study exclusive radiative decays of the using soft-collinear
effective theory and non-relativistic QCD. In contrast to inclusive radiative
decays at the endpoint we find that color-octet contributions are power
suppressed in exclusive decays, and can safely be neglected, greatly
simplifying the analysis. We determine the complete set of Lorentz structures
that can appear in the SCET Wilson coefficients and match onto them using
results from a previous calculation. We run these coefficients from the scale
\mups to the scale , thereby summing large
logarithms. Finally we use our results to predict the ratio of branching
fractions , , and the partial rate for .Comment: 17 pages, 2 figures. Updated to reflect published versio
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