4,797 research outputs found
Use of aerial survey and aerophotogrammetry methods in monitoring manatee populations
We evaluated the use of strip-transect survey methods for manatees through a
series of replicate aerial surveys in the Banana River, Brevard County, Florida, during
summer 1993 and summer 1994. Transect methods sample a representative portion of
the total study area, thus allowing for statistical extrapolation to the total area. Other
advantages of transect methods are less flight time and less cost than total coverage, ease
of navigation, and reduced likelihood of double-counting.
Our objectives were: (1) to identify visibility biases associated with the transect
survey method and to adjust the counts accordingly; (2) to derive a population estimate
with known variance for the Banana River during summer; and (3) to evaluate the
potential value of this survey method for monitoring trends in manatee population size
over time. (51 page document
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Sentinel Case of Candida auris in the Western United States Following Prolonged Occult Colonization in a Returned Traveler from India.
Candida auris is an emerging multidrug-resistant yeast with high mortality. We report the sentinel C. auris case on the United States West Coast in a patient who relocated from India. We identified close phylogenetic relatedness to the South Asia clade and ERG11 Y132F and FKS1 S639Y mutations potentially explaining antifungal resistance
Biomechanical Evaluation of Recurrent Dissociation of Modular Humeral Prostheses
The purpose of the study was to evaluate the force and torque required to dissociate a humeral head from the unimplanted modular total shoulder replacement system from different manufacturers and to determine if load and torque to dissociation are reduced in the presence of bodily fluids. Impingement, taper contamination, lack of compressive forces, and interference of taper fixation by the proximal humerus have all been reported as possible causes for dissociation. Experimental values determined in this research were compared with literature estimates of dissociation force of the humeral head under various conditions to gain more understanding of the causes of recurrent dissociations of the humeral head. This study examined biomechanical properties under dry and wet conditions under clinically practiced methods. Mean load to dissociation (1513 N ± 508 N) was found to be greater than that exerted by the activities of daily living (578 N) for all implants studied. The mean torque to dissociation was (49.77 N·m ± 19.07 N·m). Analysis of R2 correlation coefficients and p-values (α = 0.05) did not show any significant correlation between dry/bovine, dry/wet, or wet/bovine for load, displacement, or torsional stiffness in the majority of tests performed. Wetting the taper with water or bovine serum did not reduce the dissociation force to a statistically significant degree. Torque and lack of compressive forces at the rotator cuff may be the cause of dissociation at values less than those of activities of daily living. Torque data are provided by this study, but further research is needed to fully appreciate the role of torque in recurrent dissociations
Application of Appropriateness Criteria to Stress Single-Photon Emission Computed Tomography Sestamibi Studies and Stress Echocardiograms in an Academic Medical Center
ObjectivesThe purpose of this study was to apply published appropriateness criteria for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in a single academic medical center.BackgroundThe American College of Cardiology Foundation (ACCF) and the American Society of Nuclear Cardiology (ASNC) have developed appropriateness criteria for stress SPECT MPI to address concern about the growth in cardiac imaging studies.MethodsWe retrospectively examined 284 patients who underwent stress SPECT MPI and 298 patients who underwent stress echocardiography before publication of these criteria.ResultsThe overall level of agreement in characterizing appropriateness between 2 experienced cardiovascular nurse abstractors was modest (kappa = 0.56), but noticeably poorer (kappa = 0.27) for patients with previous SPECT or echo studies. Similar percentages of each imaging modality were assigned to the 3 appropriateness categories: 64% of stress SPECT and 64% of stress echo studies were classified appropriate; 11% of stress SPECT and 9% of stress echo were of uncertain appropriateness; and 14% of stress SPECT and 18% of stress echo were inappropriate. Of the inappropriate studies, 88% were performed for 1 of 4 indications. Approximately 10% of the patients were unclassifiable.ConclusionsApplication of existing SPECT MPI appropriateness criteria is demanding and requires an established database or detailed data collection, as well as a number of assumptions. Fourteen percent of stress SPECT studies and 18% of stress echo studies were performed for inappropriate reasons. Quality improvement efforts directed at reducing the number of these inappropriate studies may improve efficiency in the health care system
Effect of a magnetic field on the long-range magnetic order in insulating Nd2CuO4, nonsuperconducting and superconducting Nd1.85Ce0.15CuO4
We have measured the effect of a c-axis aligned magnetic field on the
long-range magnetic order of insulating Nd2CuO4, as-grown nonsuperconducting
and superconducting Nd1.85Ce0.15CuO4. On cooling from room temperature, Nd2CuO4
goes through a series of antiferromagnetic (AF) phase transitions with
different noncollinear spin structures. In all phases of Nd2CuO4, we find that
the applied c-axis field induces a canting of the AF order but does not alter
the basic zero-field noncollinear spin structures. Similar behavior is also
found in as-grown nonsuperconducting Nd1.85Ce0.15CuO4. These results contrast
dramatically with those of superconducting Nd1.85Ce0.15CuO4, where a c-axis
aligned magnetic field induces a static, anomalously conducting, long-range
ordered AF state. We confirm that the annealing process necessary to make
superconducting Nd1.85Ce0.15CuO4 also induces epitaxial, three-dimensional
long-range ordered cubic (Nd,Ce)2O3 as an impurity phase. In addition, the
annealing process makes a series of quasi two-dimensional superlattice
reflections associated with lattice distortions of Nd1.85Ce0.15CuO4 in the CuO2
plane. While the application of a magnetic field will induce a net moment in
the impurity phase, we determine its magnitude and eliminate this as a
possibility for the observed magnetic field-induced effect in superconducting
Nd1.85Ce0.15CuO4.Comment: 12 pages, 10 figures, to be published in Phys. Rev.
Structure and Dynamics of Superconducting NaxCoO(2) Hydrate and Its Unhydrated Analog
Neutron scattering has been used to investigate the crystal structure and
lattice dynamics of superconducting Na0.3CoO2 1.4(H/D)2O, and the parent
Na0.3CoO2 material. The structure of Na0.3CoO2 consists of alternate layers of
CoO2 and Na and is the same as the structure at higher Na concentrations. For
the superconductor, the water forms two additional layers between the Na and
CoO2, increasing the c-axis lattice parameter of the hexagonal P63/mmc space
group from 11.16 A to 19.5 A. The Na ions are found to occupy a different
configuration from the parent compound, while the water forms a structure that
replicates the structure of ice. Both types of sites are only partially
occupied. The CoO2 layer in these structures is robust, on the other hand, and
we find a strong inverse correlation between the CoO2 layer thickness and the
superconducting transition temperature (TC increases with decreasing
thickness). The phonon density-of-states for Na0.3CoO2 exhibits distinct
acoustic and optic bands, with a high-energy cutoff of ~100 meV. The lattice
dynamical scattering for the superconductor is dominated by the hydrogen modes,
with librational and bending modes that are quite similar to ice, supporting
the structural model that the water intercalates and forms ice-like layers in
the superconductor.Comment: 14 pages, 7 figures, Phys. Rev. B (in press). Minor changes + two
figures removed as requested by refere
Targeting the LOX/hypoxia axis reverses many of the features that make pancreatic cancer deadly: inhibition of LOX abrogates metastasis and enhances drug efficacy
Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer‐related mortality. Despite significant advances made in the treatment of other cancers, current chemotherapies offer little survival benefit in this disease. Pancreaticoduodenectomy offers patients the possibility of a cure, but most will die of recurrent or metastatic disease. Hence, preventing metastatic disease in these patients would be of significant benefit. Using principal component analysis (PCA), we identified a LOX/hypoxia signature associated with poor patient survival in resectable patients. We found that LOX expression is upregulated in metastatic tumors from Pdx1‐Cre KrasG12D/+ Trp53R172H/+ (KPC) mice and that inhibition of LOX in these mice suppressed metastasis. Mechanistically, LOX inhibition suppressed both migration and invasion of KPC cells. LOX inhibition also synergized with gemcitabine to kill tumors and significantly prolonged tumor‐free survival in KPC mice with early‐stage tumors. This was associated with stromal alterations, including increased vasculature and decreased fibrillar collagen, and increased infiltration of macrophages and neutrophils into tumors. Therefore, LOX inhibition is able to reverse many of the features that make PDAC inherently refractory to conventional therapies and targeting LOX could improve outcome in surgically resectable disease
High-levelexpression of functional recombinant human coagulation factor VII in insect cells
Abstract:
Recombinant coagulation factor VII (FVII) is used as a potential therapeutic intervention in hemophilia patients who produce antibodies against the coagulation factors. Mammalian cell lines provide low levels of expression, however, the Spodoptera frugiperda Sf9 cell line and baculovirus expression system are powerful systems for high-level expression of recombinant proteins, but due to the lack of endogenous vitamin K-dependent carboxylase, expression of functional FVII using this system is impossible. In the present study, we report a simple but versatile method to overcome the defect for high-level expression of the functional recombinant coagulation FVII in Sf9 cells. This method involves simultaneous expression of both human γ-carboxylase (hGC) and human FVII genes in the host. It may be possible to express other vitamin K-dependent coagulation factors using this method in the future.
Keywords: Baculovirus; γ-carboxylase; Coagulation FVII; Factor VII; Insect cel
From Quantum Systems to L-Functions: Pair Correlation Statistics and Beyond
The discovery of connections between the distribution of energy levels of
heavy nuclei and spacings between prime numbers has been one of the most
surprising and fruitful observations in the twentieth century. The connection
between the two areas was first observed through Montgomery's work on the pair
correlation of zeros of the Riemann zeta function. As its generalizations and
consequences have motivated much of the following work, and to this day remains
one of the most important outstanding conjectures in the field, it occupies a
central role in our discussion below. We describe some of the many techniques
and results from the past sixty years, especially the important roles played by
numerical and experimental investigations, that led to the discovery of the
connections and progress towards understanding the behaviors. In our survey of
these two areas, we describe the common mathematics that explains the
remarkable universality. We conclude with some thoughts on what might lie ahead
in the pair correlation of zeros of the zeta function, and other similar
quantities.Comment: Version 1.1, 50 pages, 6 figures. To appear in "Open Problems in
Mathematics", Editors John Nash and Michael Th. Rassias. arXiv admin note:
text overlap with arXiv:0909.491
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