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Biomechanical Computed Tomography analysis (BCT) for clinical assessment of osteoporosis.
The surgeon general of the USA defines osteoporosis as "a skeletal disorder characterized by compromised bone strength, predisposing to an increased risk of fracture." Measuring bone strength, Biomechanical Computed Tomography analysis (BCT), namely, finite element analysis of a patient's clinical-resolution computed tomography (CT) scan, is now available in the USA as a Medicare screening benefit for osteoporosis diagnostic testing. Helping to address under-diagnosis of osteoporosis, BCT can be applied "opportunistically" to most existing CT scans that include the spine or hip regions and were previously obtained for an unrelated medical indication. For the BCT test, no modifications are required to standard clinical CT imaging protocols. The analysis provides measurements of bone strength as well as a dual-energy X-ray absorptiometry (DXA)-equivalent bone mineral density (BMD) T-score at the hip and a volumetric BMD of trabecular bone at the spine. Based on both the bone strength and BMD measurements, a physician can identify osteoporosis and assess fracture risk (high, increased, not increased), without needing confirmation by DXA. To help introduce BCT to clinicians and health care professionals, we describe in this review the currently available clinical implementation of the test (VirtuOst), its application for managing patients, and the underlying supporting evidence; we also discuss its main limitations and how its results can be interpreted clinically. Together, this body of evidence supports BCT as an accurate and convenient diagnostic test for osteoporosis in both sexes, particularly when used opportunistically for patients already with CT. Biomechanical Computed Tomography analysis (BCT) uses a patient's CT scan to measure both bone strength and bone mineral density at the hip or spine. Performing at least as well as DXA for both diagnosing osteoporosis and assessing fracture risk, BCT is particularly well-suited to "opportunistic" use for the patient without a recent DXA who is undergoing or has previously undergone CT testing (including hip or spine regions) for an unrelated medical condition
The Portrayal of Complementary and Alternative Medicine in Mass Print Magazines Since 1980
Objectives: The objectives of this study were to examine and describe the portrayal of complementary and alternative medicine (CAM) in mass print media magazines.
Design: The sample included all 37 articles found in magazines with circulation rates of greater than 1 million published in the United States and Canada from 1980 to 2005. The analysis was quantitative and qualitative and included investigation of both manifest and latent magazine story messages.
Results: Manifest analysis noted that CAM was largely represented as a treatment for a patient with a medically diagnosed illness or specific symptoms. Discussions used biomedical terms such as patient rather than consumer and disease rather than wellness. Latent analysis revealed three themes: (1) CAMs were described as good but not good enough; (2) individualism and consumerism were venerated; and (3) questions of costs were raised in the context of confusion and ambivalence
Recombinant Human Parathyroid Hormone Effect on Health-Related Quality of Life in Adults With Chronic Hypoparathyroidism
Context: Reduced health-related quality of life (HRQoL) is common in patients with hypoparathyroidism on conventional therapy with calcium and active vitamin D supplements. Objective: To examine the effects of recombinant human parathyroid hormone (rhPTH[1-84]) on HRQoL as measured by the 36-Item Short Form Health Survey (SF-36) during the multinational, randomized, placebo-controlled REPLACE study. Patients: 122 adults with chronic hypoparathyroidism. Intervention(s): Following an optimization period when calcium and/or active vitamin D supplements were adjusted to reach target serum calcium levels (8.0-9.0 mg/dL; 2.0-2.2 mmol/L), patients were randomized to receive placebo (n=39) or rhPTH(1-84) (n=83) (starting dose 50 mug/day, could be titrated up to 100 mug/day); supplement doses were adjusted to maintain target serum calcium levels. Main Outcome Measure(s): Change from baseline (post-optimization, at randomization) to Week 24 in HRQoL as assessed by the SF-36v2 health survey. Results: Overall, the between-group differences were not statistically significant. However, in the rhPTH(1-84) group, there were significant improvements in the physical component summary score (P=0.004) and in body pain (P<0.05), general health (P<0.05), and vitality (P<0.001) domains as compared with baseline values. In the placebo group, there were no significant changes for any of the domains. The magnitude of change between 0 and 24 weeks in SF-36 scores was negatively correlated with baseline scores, such that patients with lower HRQoL at baseline were more likely to experience improvement in response to treatment. Conclusions: Treatment with rhPTH(1-84) may improve HRQoL in adults with hypoparathyroidism
Star Routing: Between Vehicle Routing and Vertex Cover
We consider an optimization problem posed by an actual newspaper company,
which consists of computing a minimum length route for a delivery truck, such
that the driver only stops at street crossings, each time delivering copies to
all customers adjacent to the crossing. This can be modeled as an abstract
problem that takes an unweighted simple graph and a subset of
edges and asks for a shortest cycle, not necessarily simple, such that
every edge of has an endpoint in the cycle.
We show that the decision version of the problem is strongly NP-complete,
even if is a grid graph. Regarding approximate solutions, we show that the
general case of the problem is APX-hard, and thus no PTAS is possible unless P
NP. Despite the hardness of approximation, we show that given any
-approximation algorithm for metric TSP, we can build a
-approximation algorithm for our optimization problem, yielding a
concrete -approximation algorithm.
The grid case is of particular importance, because it models a city map or
some part of it. A usual scenario is having some neighborhood full of
customers, which translates as an instance of the abstract problem where almost
every edge of is in . We model this property as , and
for these instances we give a -approximation algorithm,
for any , provided that the grid is sufficiently big.Comment: Accepted to the 12th Annual International Conference on Combinatorial
Optimization and Applications (COCOA'18
Minimal metabolic pathway structure is consistent with associated biomolecular interactions
Pathways are a universal paradigm for functionally describing cellular processes. Even though advances in high-throughput data generation have transformed biology, the core of our biological understanding, and hence data interpretation, is still predicated on human-defined pathways. Here, we introduce an unbiased, pathway structure for genome-scale metabolic networks defined based on principles of parsimony that do not mimic canonical human-defined textbook pathways. Instead, these minimal pathways better describe multiple independent pathway-associated biomolecular interaction datasets suggesting a functional organization for metabolism based on parsimonious use of cellular components. We use the inherent predictive capability of these pathways to experimentally discover novel transcriptional regulatory interactions in Escherichia coli metabolism for three transcription factors, effectively doubling the known regulatory roles for Nac and MntR. This study suggests an underlying and fundamental principle in the evolutionary selection of pathway structures; namely, that pathways may be minimal, independent, and segregated
Preliminary Limits on the WIMP-Nucleon Cross Section from the Cryogenic Dark Matter Search (CDMS)
We are conducting an experiment to search for WIMPs, or weakly-interacting
massive particles, in the galactic halo using terrestrial detectors. This
generic class of hypothetical particles, whose properties are similar to those
predicted by extensions of the standard model of particle physics, could
comprise the cold component of non-baryonic dark matter. We describe our
experiment, which is based on cooled germanium and silicon detectors in a
shielded low-background cryostat. The detectors achieve a high degree of
background rejection through the simultaneous measurement of the energy in
phonons and ionization. Using exposures on the order of one kilogram-day from
initial runs of our experiment, we have achieved (preliminary) upper limits on
the WIMP-nucleon cross section that are comparable to much longer runs of other
experiments.Comment: 5 LaTex pages, 5 eps figs, epsf.sty, espcrc2dsa2.sty. Proceedings of
TAUP97, Gran Sasso, Italy, 7-11 Sep 1997, Nucl. Phys. Suppl., A. Bottino, A.
di Credico and P. Monacelli (eds.). See also http://cfpa.berkeley.ed
Inconsistent boundaries
Research on this paper was supported by a grant from the Marsden Fund, Royal Society of New Zealand.Mereotopology is a theory of connected parts. The existence of boundaries, as parts of everyday objects, is basic to any such theory; but in classical mereotopology, there is a problem: if boundaries exist, then either distinct entities cannot be in contact, or else space is not topologically connected (Varzi in Noûs 31:26–58, 1997). In this paper we urge that this problem can be met with a paraconsistent mereotopology, and sketch the details of one such approach. The resulting theory focuses attention on the role of empty parts, in delivering a balanced and bounded metaphysics of naive space.PostprintPeer reviewe
The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)
The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans
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