3,584 research outputs found
Spontaneous showering of tumor emboli in a patient with advanced primary lung cancer: a case report
Extension of primary lung tumors into the left atrium via pulmonary veins is a well-documented phenomenon. Peripheral arterial embolism and cerebral embolism originating from a primary lung neoplasm are rare events. We report a case of simultaneous acute bilateral lower limb ischemia, bilateral renal infarction, splenic infarction and cerebral infarction as a result of multiple emboli originating from primary lung malignancy invasion of the left atrium. An emergent embolectomy revealed pathologic features of the extracted thrombus that were identical to the pulmonary neoplasm
Effects of disrupting the polyketide synthase gene WdPKS1 in Wangiella [Exophiala] dermatitidis on melanin production and resistance to killing by antifungal compounds, enzymatic degradation, and extremes in temperature
BACKGROUND: Wangiella dermatitidis is a human pathogenic fungus that is an etiologic agent of phaeohyphomycosis. W. dermatitidis produces a black pigment that has been identified as a dihydroxynaphthalene melanin and the production of this pigment is associated with its virulence. Cell wall pigmentation in W. dermatitidis depends on the WdPKS1 gene, which encodes a polyketide synthase required for generating the key precursor for dihydroxynaphthalene melanin biosynthesis. RESULTS: We analyzed the effects of disrupting WdPKS1 on dihydroxynaphthalene melanin production and resistance to antifungal compounds. Transmission electron microscopy revealed that wdpks1Δ-1 yeast had thinner cell walls that lacked an electron-opaque layer compared to wild-type cells. However, digestion of the wdpks1Δ-1 yeast revealed small black particles that were consistent with a melanin-like compound, because they were acid-resistant, reacted with melanin-binding antibody, and demonstrated a free radical signature by electron spin resonance analysis. Despite lacking the WdPKS1 gene, the mutant yeast were capable of catalyzing the formation of melanin from L-3,4-dihyroxyphenylalanine. The wdpks1Δ-1 cells were significantly more susceptible to killing by voriconazole, amphotericin B, NP-1 [a microbicidal peptide], heat and cold, and lysing enzymes than the heavily melanized parental or complemented strains. CONCLUSION: In summary, W. dermatitidis makes WdPKS-dependent and -independent melanins, and the WdPKS1-dependent deposition of melanin in the cell wall confers protection against antifungal agents and environmental stresses. The biological role of the WdPKS-independent melanin remains unclear
Cascade MIMO P-PID controllers applied in an over-actuated quadrotor Tilt-Rotor
To map the Virtual Control Actions (VCAs) into
Real Control Actions (RCAs), over-actuated systems typically
require nonlinear control allocation methods. On embedded
robotic platforms, computational efforts are not always available.
With this in mind, this work presents the design of a
Quadrotor Tilt-Rotor (QTR) through a new concept of control
allocation with uncoupled RCAs, where a nonlinear system is
divided into partially dependent and linear subsystems with fast
and robust convergence. The RCAs are divided into smaller
and linearized sets and solved sequentially. Then, the cascade
Multipe-Input-Multipe-Output (MIMO) Proportional (P)-
Proportional, Integral and Derivative (PID) controllers tuning
were presented with saturation constants and successive loop
closure technique, where some open-field environment tests were
conducted to validate the respective tuning. In the end, it showed
to be reliable, robust, efficient, and applicable when VCAs are
overlapped between the subsystems.The authors would like to thank CEFET-MG and Leuphana
University of L¨uneburg for their financial support.info:eu-repo/semantics/publishedVersio
Electron Abundance in Protostellar Cores
The determination of the fractional electron abundance, Xe, in protostellar
cores relies on observations of molecules, such as DCO+, H13CO+ and CO, and on
chemical models to interpret their abundance. Studies of protostellar cores
have revealed significant variations of Xe from core to core within a range
10^-8<Xe<10^-6. The physical origin of these large variations in Xe is not well
understood, unless unlikely variations in the cosmic ray ionization rate or ad
hoc values of metal depletion are assumed. In this work we explore other
potential causes of these variations in Xe, including core age, extinction and
density. We compute numerically the intensity of the radiation field within a
density distribution generated by supersonic turbulence. Taking into account
the lines of sight in all directions, the effective visual extinction in dense
regions is found to be always much lower than the extinction derived from the
column density along a fixed line of sight. Dense cores with volume and column
densities comparable to observed protostellar cores have relatively low
mass-averaged visual extinction, 2mag <= A_V <= 5mag, such that
photo-ionization can sometimes be as important as cosmic ray ionization.
Chemical models, including gas-grain chemistry and time dependent gas depletion
and desorption, are computed for values of visual extinction in the range 2mag
<= A_V <= 6mag, and for a hydrogen gas density of 10^4cm^-3$, typical of
protostellar cores. The models presented here can reproduce some of the
observed variations of ion abundance from core to core as the combined effect
of visual extinction and age variations. The range of electron abundances
predicted by the models is relatively insenstive to density over 10^4 to 10^6
cm^{-3}.Comment: 25 pages, 9 figures. Astrophysical Journal, in pres
Patients with MEN1 are at an increased risk for venous thromboembolism VTE risk in MEN1
Background: Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited disorder predisposing to the development of multiple functional and non-functional neuroendocrine tumors (NETs). Only uncommon MEN1-associated functional NETs such as glucagonomas (<1%) and ACTH-producing tumors (<5%) are known to be associated with hypercoagulability. It is unknown if patients with MEN1 generally have increased risk of VTE.
Methods: We queried a prospective natural history study of germline mutation positive MEN1 patients (n=286) between 1991-2019 for all lifetime events of VTE. Search terms were: DVT, thromb, embol, PE, pulmonary embolism, clot, hematology consult, anticoagulant, coumadin, lovenox, xarelto, warfarin, aspirin, rivaroxaban and apixaban. Incidence rates were calculated accounting for age and sex. Comparison was made to published incidence rates in healthy populations, different types of cancer, and Cushing's syndrome.
Results: Thirty-six subjects (median age 45 years, range 16-75) experienced a VTE event, yielding a prevalence rate of 12.9%. The age-sex adjusted incidence rate of VTE is 9.11 per 1,000 patient-years, with a sex-adjusted lifetime incidence rate of 2.81 per 1,000 patient-years. MEN1-associated lifetime incidence rates are ~two-fold higher than the estimated annual incidence rate in the general population and are comparable to known risk in the setting of various types of cancer. Approximately 80% were diagnosed with pancreatic NETs, of which 24% were insulinomas. Fourteen patients (42%) experienced peri-operative VTE events.
Conclusions: MEN1 patients have an increased risk of VTE. Further mechanistic investigation and validation from other MEN1 cohorts are needed to confirm the increased prevalence of VTE in MEN1
Demonstration of tunable three-body interactions between superconducting qubits
Nonpairwise multi-qubit interactions present a useful resource for quantum
information processors. Their implementation would facilitate more efficient
quantum simulations of molecules and combinatorial optimization problems, and
they could simplify error suppression and error correction schemes. Here we
present a superconducting circuit architecture in which a coupling module
mediates 2-local and 3-local interactions between three flux qubits by design.
The system Hamiltonian is estimated via multi-qubit pulse sequences that
implement Ramsey-type interferometry between all neighboring excitation
manifolds in the system. The 3-local interaction is coherently tunable over
several MHz via the coupler flux biases and can be turned off, which is
important for applications in quantum annealing, analog quantum simulation, and
gate-model quantum computation.Comment: 14 pages, 11 figure
Scaling of oscillatory kinematics and Froude efficiency in baleen whales
High efficiency lunate-tail swimming with high-aspect-ratio lifting surfaces has evolved in many vertebrate lineages, from fish to cetaceans. Baleen whales (Mysticeti) are the largest swimming animals that exhibit this locomotor strategy, and present an ideal study system to examine how morphology and the kinematics of swimming scale to the largest body sizes. We used data from whale-borne inertial sensors coupled with morphometric measurements from aerial drones to calculate the hydrodynamic performance of oscillatory swimming in six baleen whale species ranging in body length from 5 to 25 m (fin whale, Balaenoptera physalus; Bryde\u27s whale, Balaenoptera edeni; sei whale, Balaenoptera borealis; Antarctic minke whale, Balaenoptera bonaerensis; humpback whale, Megaptera novaeangliae; and blue whale, Balaenoptera musculus). We found that mass-specific thrust increased with both swimming speed and body size. Froude efficiency, defined as the ratio of useful power output to the rate of energy input (Sloop, 1978), generally increased with swimming speed but decreased on average with increasing body size. This finding is contrary to previous results in smaller animals, where Froude efficiency increased with body size. Although our empirically parameterized estimates for swimming baleen whale drag were higher than those of a simple gliding model, oscillatory locomotion at this scale exhibits generally high Froude efficiency as in other adept swimmers. Our results quantify the fine-scale kinematics and estimate the hydrodynamics of routine and energetically expensive swimming modes at the largest scale
The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics Imaging
We present diffraction-limited \ks band and \lprime adaptive optics images of
the edge-on debris disk around the nearby F2 star HD 15115, obtained with a
single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the
disk is detected at signal-to-noise per resolution element (SNRE) \about 3-8
from \about 1-2\fasec 5 (45-113 AU) on the western side, and from \about
1.2-2\fasec 1 (63-90 AU) on the east. At \lprime the disk is detected at SNRE
\about 2.5 from \about 1-1\fasec 45 (45-90 AU) on both sides, implying more
symmetric disk structure at 3.8 \microns . At both wavelengths the disk has a
bow-like shape and is offset from the star to the north by a few AU. A surface
brightness asymmetry exists between the two sides of the disk at \ks band, but
not at \lprime . The surface brightness at \ks band declines inside 1\asec
(\about 45 AU), which may be indicative of a gap in the disk near 1\asec. The
\ks - \lprime disk color, after removal of the stellar color, is mostly grey
for both sides of the disk. This suggests that scattered light is coming from
large dust grains, with 3-10 \microns -sized grains on the east side and 1-10
\microns dust grains on the west. This may suggest that the west side is
composed of smaller dust grains than the east side, which would support the
interpretation that the disk is being dynamically affected by interactions with
the local interstellar medium.Comment: Apj-accepted March 27 2012; minor correction
Identification of Class I HLA T Cell Control Epitopes for West Nile Virus
The recent West Nile virus (WNV) outbreak in the United States underscores the importance of understanding human immune responses to this pathogen. Via the presentation of viral peptide ligands at the cell surface, class I HLA mediate the T cell recognition and killing of WNV infected cells. At this time, there are two key unknowns in regards to understanding protective T cell immunity: 1) the number of viral ligands presented by the HLA of infected cells, and 2) the distribution of T cell responses to these available HLA/viral complexes. Here, comparative mass spectroscopy was applied to determine the number of WNV peptides presented by the HLA-A*11:01 of infected cells after which T cell responses to these HLA/WNV complexes were assessed. Six viral peptides derived from capsid, NS3, NS4b, and NS5 were presented. When T cells from infected individuals were tested for reactivity to these six viral ligands, polyfunctional T cells were focused on the GTL9 WNV capsid peptide, ligands from NS3, NS4b, and NS5 were less immunogenic, and two ligands were largely inert, demonstrating that class I HLA reduce the WNV polyprotein to a handful of immune targets and that polyfunctional T cells recognize infections by zeroing in on particular HLA/WNV epitopes. Such dominant HLA/peptide epitopes are poised to drive the development of WNV vaccines that elicit protective T cells as well as providing key antigens for immunoassays that establish correlates of viral immunity. © 2013 Kaabinejadian et al
First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs
As the only directly imaged multiple planet system, HR 8799 provides a unique
opportunity to study the physical properties of several planets in parallel. In
this paper, we image all four of the HR 8799 planets at H-band and 3.3 microns
with the new LBT adaptive optics system, PISCES, and LBTI/LMIRCam. Our images
offer an unprecedented view of the system, allowing us to obtain H and 3.3$
micron photometry of the innermost planet (for the first time) and put strong
upper-limits on the presence of a hypothetical fifth companion. We find that
all four planets are unexpectedly bright at 3.3 microns compared to the
equilibrium chemistry models used for field brown dwarfs, which predict that
planets should be faint at 3.3 microns due to CH4 opacity. We attempt to model
the planets with thick-cloudy, non-equilibrium chemistry atmospheres, but find
that removing CH4 to fit the 3.3 micron photometry increases the predicted L'
(3.8 microns) flux enough that it is inconsistent with observations. In an
effort to fit the SED of the HR 8799 planets, we construct mixtures of cloudy
atmospheres, which are intended to represent planets covered by clouds of
varying opacity. In this scenario, regions with low opacity look hot and
bright, while regions with high opacity look faint, similar to the patchy cloud
structures on Jupiter and L/T transition brown-dwarfs. Our mixed cloud models
reproduce all of the available data, but self-consistent models are still
necessary to demonstrate their viability.Comment: Accepted to Ap
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