2,439 research outputs found
Phenotypic Characterization of Chicken Thymic Stromal Elements
Phenotypic profiles of the thymic stromal components provide an excellent approach to
elucidating the nature of the microenvironment of this organ. To address this issue in
chickens, we have produced an extensive panel of 18 mAb to the thymic stroma. These
mAb have been extensively characterized with respect to their phenotypic specificities
and reveal that the stromal cells are equally as complex as the T cells whose maturation
they direct. They further demonstrate that, in comparison to the mammalian thymus,
there is a remarkable degree of conservation in thymic architecture between
phylogenetically diverse species. Eleven mAb reacted with thymic epithelial cells: MUI-73 was panepithelium, MUI-54 stained all cortical and medullary epithelium but only a
minority of the subcapsule, MUI-52 was specific for isolated stellate cortical epithelial
cells, MUI-62, -69, and -71 were specific for the medulla (including Hassall’s corpusclelike
structures), MUI-51, -53, -70, and -75 reacted only with the type-I epithelium, or
discrete regions therein, lining the subcapsular and perivascular regions and MUI-58
demonstrated the antigenic similarity between the subcapsule and the medulla. Seven
other mAb identified distinct isolated stromal cells throughout the cortex and medulla.
Large thymocyte-rich regions, which often spanned from the outer cortex to medulla,
lacked epithelial cells. These mAb should prove invaluable for determining the
functional significance of thymic stromal-cell subsets to thymopoiesis
Selecting soil hydraulic properties as indicators of soil health: Measurement response to management and site characteristics
Caregiver responses to symptoms of first-onset psychosis: A comparative study of Chinese-and Euro-Canadian families
Considerable evidence suggests that ethnic Chinese families in Canada are reluctant to seek psychiatric treatment for a relative with mental illness. The following hypotheses were investigated: (a) longer delay in seeking treatment among Chinese versus Euro-Canadians; (b) greater burden among Chinese versus Euro-Canadians; and (c) more negative conceptions of mental illness among Chinese versus Euro-Canadians. The sample consisted of 18 Chinese Canadians and 36 Euro-Canadians experiencing a first episode of psychosis; each participant recruited a parent or sibling who responded to measures of perceived family burden and attitudes toward mental illness. Results confirmed all three hypotheses. Chinese care-givers were particularly more likely to endorse the practice of keeping mental illness a secret from others, as well as withdrawal from individuals with mental illness. These findings suggest that Chinese caregivers were more affected by the stigma of mental illness than were Euro-Canadian caregivers
MicroRNA Biomarkers for Infectious Diseases: From Basic Research to Biosensing
In the pursuit of improved diagnostic tests for infectious diseases, several classes of molecules have been scrutinized as prospective biomarkers. Small (18–22 nucleotide), non-coding RNA transcripts called microRNAs (miRNAs) have emerged as promising candidates with extensive diagnostic potential, due to their role in numerous diseases, previously established methods for quantitation and their stability within biofluids. Despite efforts to identify, characterize and apply miRNA signatures as diagnostic markers in a range of non-infectious diseases, their application in infectious disease has advanced relatively slowly. Here, we outline the benefits that miRNA biomarkers offer to the diagnosis, management, and treatment of infectious diseases. Investigation of these novel biomarkers could advance the use of personalized medicine in infectious disease treatment, which raises important considerations for validating their use as diagnostic or prognostic markers. Finally, we discuss new and emerging miRNA detection platforms, with a focus on rapid, point-of-care testing, to evaluate the benefits and obstacles of miRNA biomarkers for infectious disease
The Application of Nanopore Sequencing Technology to the Study of Dinoflagellates:A Proof of Concept Study for Rapid Sequence-Based Discrimination of Potentially Harmful Algae
New invasive Nemertean species (Cephalothrix Simula) in England with high levels of tetrodotoxin and a microbiome linked to toxin metabolism
The marine nemertean Cephalothrix simula originates from the Pacific Ocean but in recent years has been discovered in northern Europe. The species has been associated with high levels of the marine neurotoxin Tetrodotoxin, traditionally associated with Pufferfish Poisoning. This study reports the first discovery of two organisms of C. simula in the UK, showing the geographical extent of this species is wider than originally described. Species identification was initially conducted morphologically, with confirmation by Cox 1 DNA sequencing. 16S gene sequencing enabled the taxonomic assignment of the microbiome, showing the prevalence of a large number of bacterial genera previously associated with TTX production including Alteromonas, Vibrio and Pseudomonas. LC-MS/MS analysis of the nemertean tissue revealed the presence of multiple analogues of TTX, dominated by the parent TTX, with a total toxin concentration quantified at 54 µg TTX per g of tissue. Pseudomonas luteola isolated from C. simula, together with Vibrio alginolyticus from the native nemertean Tubulanus annulatus, were cultured at low temperature and both found to contain TTX. Overall, this paper confirms the high toxicity of a newly discovered invasive nemertean species with links to toxin-producing marine bacteria and the potential risk to human safety. Further work is required to assess the geographical extent and toxicity range of C. simula along the UK coast in order to properly gauge the potential impacts on the environment and human safety
A Substellar Companion in a 1.3 yr Nearly-circular Orbit of HD 16760
We report the detection of a substellar companion orbiting the G5 dwarf HD
16760 from the N2K sample. Precise Doppler measurements of the star from Subaru
and Keck revealed a Keplerian velocity variation with a period of 466.47+-0.35
d, a semiamplitude of 407.71+-0.84 m/s, and an eccentricity of 0.084+-0.003.
Adopting a stellar mass of 0.78+-0.05 M_Sun, we obtain a minimum mass for the
companion of 13.13+-0.56 M_JUP, which is close to the planet/brown-dwarf
transition, and the semimajor axis of 1.084+-0.023 AU. The nearly circular
orbit despite the large mass and intermediate orbital period makes this
companion unique among known substellar companions.Comment: 14 pages, 2 figures, accepted for publication in Ap
Stochastic Inflation Revisited: Non-Slow Roll Statistics and DBI Inflation
Stochastic inflation describes the global structure of the inflationary
universe by modeling the super-Hubble dynamics as a system of matter fields
coupled to gravity where the sub-Hubble field fluctuations induce a stochastic
force into the equations of motion. The super-Hubble dynamics are ultralocal,
allowing us to neglect spatial derivatives and treat each Hubble patch as a
separate universe. This provides a natural framework in which to discuss
probabilities on the space of solutions and initial conditions. In this article
we derive an evolution equation for this probability for an arbitrary class of
matter systems, including DBI and k-inflationary models, and discover
equilibrium solutions that satisfy detailed balance. Our results are more
general than those derived assuming slow roll or a quasi-de Sitter geometry,
and so are directly applicable to models that do not satisfy the usual slow
roll conditions. We discuss in general terms the conditions for eternal
inflation to set in, and we give explicit numerical solutions of highly
stochastic, quasi-stationary trajectories in the relativistic DBI regime.
Finally, we show that the probability for stochastic/thermal tunneling can be
significantly enhanced relative to the Hawking-Moss instanton result due to
relativistic DBI effects.Comment: 38 pages, 2 figures. v3: minor revisions; version accepted into JCA
Cosmological expansion on a dilatonic brane-world
In this paper we study brane-world scenarios with a bulk scalar field, using
a covariant formalism to obtain a 4D Einstein equation via projection onto the
brane. We discuss, in detail, the effects of the bulk on the brane and how the
scalar field contribute to the gravitational effects. We also discuss choice of
conformal frame and show that the frame selected by the induced metric provides
a natural choice. We demonstrate our formalism by applying it to cosmological
scenarios of Randall-Sundrum and Horava-Witten type models. Finally we consider
the cosmology of models where the scalar field couples non-minimally to the
matter on the brane. This gives rise to a novel scenario where the universe
expands from a finite scale factor with an initial period of accelerated
expansion, thus avoiding the singularity and flatness problem of the standard
big bang model.Comment: 20 pages - Version to appear in Classical and Quantum Gravity. New
section added on conformal rescaling of the metric. Some other minor changes
made and references adde
Impairment of Coronary Arteriolar Endothelium-Dependent Dilation after Multi-Walled Carbon Nanotube Inhalation: A Time-Course Study
Engineered nanomaterials have been developed for widespread applications due to many highly unique and desirable characteristics. The purpose of this study was to assess pulmonary inflammation and subepicardial arteriolar reactivity in response to multi-walled carbon nanotube (MWCNT) inhalation and evaluate the time course of vascular alterations. Rats were exposed to MWCNT aerosols producing pulmonary deposition. Pulmonary inflammation via bronchoalveolar lavage and MWCNT translocation from the lungs to systemic organs was evident 24 h post-inhalation. Coronary arterioles were evaluated 24–168 h post-exposure to determine microvascular response to changes in transmural pressure, endothelium-dependent and -independent reactivity. Myogenic responsiveness, vascular smooth muscle reactivity to nitric oxide, and α-adrenergic responses all remained intact. However, a severe impact on endothelium-dependent dilation was observed within 24 h after MWCNT inhalation, a condition which improved, but did not fully return to control after 168 h. In conclusion, results indicate that MWCNT inhalation not only leads to pulmonary inflammation and cytotoxicity at low lung burdens, but also a low level of particle translocation to systemic organs. MWCNT inhalation also leads to impairments of endothelium-dependent dilation in the coronary microcirculation within 24 h, a condition which does not fully dissipate within 168 h. The innovations within the field of nanotechnology, while exciting and novel, can only reach their full potential if toxicity is first properly assessed
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