1,192 research outputs found
The rational development of molecularly imprinted polymer-based sensors for protein detection.
The detection of specific proteins as biomarkers of disease, health status,
environmental monitoring, food quality, control of fermenters and civil defence
purposes means that biosensors for these targets will become increasingly more
important. Among the technologies used for building specific recognition
properties, molecularly imprinted polymers (MIPs) are attracting much attention.
In this critical review we describe many methods used for imprinting recognition
for protein targets in polymers and their incorporation with a number of
transducer platforms with the aim of identifying the most promising approaches
for the preparation of MIP-based protein sensors (277 references)
Body fineness ratio as a predictor of maximum prolonged-swimming speed in coral reef fishes
The ability to sustain high swimming speeds is believed to be an important factor affecting resource acquisition in fishes. While we have gained insights into how fin morphology and motion influences swimming performance in coral reef fishes, the role of other traits, such as body shape, remains poorly understood. We explore the ability of two mechanistic models of the causal relationship between body fineness ratio and endurance swimming-performance to predict maximum prolonged-swimming speed (Umax ) among 84 fish species from the Great Barrier Reef, Australia. A drag model, based on semi-empirical data on the drag of rigid, submerged bodies of revolution, was applied to species that employ pectoral-fin propulsion with a rigid body at U max. An alternative model, based on the results of computer simulations of optimal shape in self-propelled undulating bodies, was applied to the species that swim by body-caudal-fin propulsion at Umax . For pectoral-fin swimmers, Umax increased with fineness, and the rate of increase decreased with fineness, as predicted by the drag model. While the mechanistic and statistical models of the relationship between fineness and Umax were very similar, the mechanistic (and statistical) model explained only a small fraction of the variance in Umax . For body-caudal-fin swimmers, we found a non-linear relationship between fineness and Umax , which was largely negative over most of the range of fineness. This pattern fails to support either predictions from the computational models or standard functional interpretations of body shape variation in fishes. Our results suggest that the widespread hypothesis that a more optimal fineness increases endurance-swimming performance via reduced drag should be limited to fishes that swim with rigid bodies.MEA was partially supported by National Science Foundation Division of Environmental Biology (NSF DEB) grant 0842397 (http://www.nsf.gov/div/
index.jsp?div = DEB). CJF was partially supported by the Australian Research Council (http://www.arc.gov.au/)
An analysis of the masking of speech by competing speech using self-report data (L)
Many of the items in the "Speech, Spatial, and Qualities of Hearing" scale questionnaire [S. Gatehouse and W. Noble, Int. J. Audiol. 43, 85–99 (2004)] are concerned with speech understanding in a variety of backgrounds, both speech and nonspeech. To study if this self-report data reflected informational masking, previously collected data on 414 people were analyzed. The lowest scores (greatest difficulties) were found for the two items in which there were two speech targets, with successively higher scores for competing speech (six items), energetic masking (one item), and no masking (three items). The results suggest significant masking by competing speech in everyday listening situations
A unified encyclopedia of human functional DNA elements through fully automated annotation of 164 human cell types [preprint]
Semi-automated genome annotation methods such as Segway enable understanding of chromatin activity. Here we present chromatin state annotations of 164 human cell types using 1,615 genomics data sets. To produce these annotations, we developed a fully-automated annotation strategy in which we train separate unsupervised annotation models on each cell type and use a machine learning classifier to automate the state interpretation step. Using these annotations, we developed a measure of the functional importance of each genomic position called the functionality score, which allows us to aggregate information across cell types into a multi-cell type view. This score provides a measure of importance directly attributable to a specific activity in a specific set of cell types. In contrast to evolutionary conservation, this measure is not biased to detect only elements shared with related species. Using the functionality score, we combined all our annotations into a single cell type-agnostic encyclopedia that catalogs all human functional regulatory elements, enabling easy and intuitive interpretation of the effect of genome variants on phenotype, such as in disease-associated, evolutionarily conserved or positively selected loci. These resources, including cell type-specific annotations, enyclopedia, and a visualization server, are available at http://noble.gs.washington.edu/proj/encyclopedia
Recommended from our members
Mother-child histocompatibility and risk of rheumatoid arthritis and systemic lupus erythematosus among mothers.
The study objective was to test the hypothesis that having histocompatible children increases the risk of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), possibly by contributing to the persistence of fetal cells acquired during pregnancy. We conducted a case control study using data from the UC San Francisco Mother Child Immunogenetic Study and studies at the Inova Translational Medicine Institute. We imputed human leukocyte antigen (HLA) alleles and minor histocompatibility antigens (mHags). We created a variable of exposure to histocompatible children. We estimated an average sequence similarity matching (SSM) score for each mother based on discordant mother-child alleles as a measure of histocompatibility. We used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals. A total of 138 RA, 117 SLE, and 913 control mothers were analyzed. Increased risk of RA was associated with having any child compatible at HLA-B (OR 1.9; 1.2-3.1), DPB1 (OR 1.8; 1.2-2.6) or DQB1 (OR 1.8; 1.2-2.7). Compatibility at mHag ZAPHIR was associated with reduced risk of SLE among mothers carrying the HLA-restriction allele B*07:02 (n = 262; OR 0.4; 0.2-0.8). Our findings support the hypothesis that mother-child histocompatibility is associated with risk of RA and SLE
Bifurcations of discrete breathers in a diatomic Fermi-Pasta-Ulam chain
Discrete breathers are time-periodic, spatially localized solutions of the
equations of motion for a system of classical degrees of freedom interacting on
a lattice. Such solutions are investigated for a diatomic Fermi-Pasta-Ulam
chain, i. e., a chain of alternate heavy and light masses coupled by anharmonic
forces. For hard interaction potentials, discrete breathers in this model are
known to exist either as ``optic breathers'' with frequencies above the optic
band, or as ``acoustic breathers'' with frequencies in the gap between the
acoustic and the optic band. In this paper, bifurcations between different
types of discrete breathers are found numerically, with the mass ratio m and
the breather frequency omega as bifurcation parameters. We identify a period
tripling bifurcation around optic breathers, which leads to new breather
solutions with frequencies in the gap, and a second local bifurcation around
acoustic breathers. These results provide new breather solutions of the FPU
system which interpolate between the classical acoustic and optic modes. The
two bifurcation lines originate from a particular ``corner'' in parameter space
(omega,m). As parameters lie near this corner, we prove by means of a center
manifold reduction that small amplitude solutions can be described by a
four-dimensional reversible map. This allows us to derive formally a continuum
limit differential equation which characterizes at leading order the
numerically observed bifurcations.Comment: 30 pages, 10 figure
Integrated High-Speed Torque Control System for a Robotic Joint
A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA)
Recommended from our members
Peto's paradox and human cancers
Peto's paradox is the lack of the expected trend in cancer incidence as a function of body size and lifespan across species. The leading hypothesis to explain this pattern is natural selection for differential cancer prevention in larger, longer lived species. We evaluate whether a similar effect exists within species, specifically humans. We begin by reanalysing a recently published dataset to separate the effects of stem cell number and replication rate, and show that each has an independent effect on cancer risk. When considering the lifetime number of stem cell divisions in an extended dataset, and removing cases associated with other diseases or carcinogens, we find that lifetime cancer risk per tissue saturates at approximately 0.3-1.3% for the types considered. We further demonstrate that grouping by anatomical site explains most of the remaining variation. Our results indicate that cancer risk depends not only on the number of stem cell divisions but varies enormously (approx. 10 000 times) depending on anatomical site. We conclude that variation in risk of human cancer types is analogous to the paradoxical lack of variation in cancer incidence among animal species and may likewise be understood as a result of evolution by natural selection
Role of cell cycle events and apoptosis in mediating the anti-cancer activity of a silver(I) complex of 4-hydroxy-3-nitro-coumarin-bis(phenanthroline) in human malignant cancer cells.
The central objective of the current study was to investigate the potential in vitro anti-proliferative effect of
4-hydroxy-3-nitro-coumarin (hncH), and the mixed-ligand silver (I) complex of 4-oxy-3-nitro-coumarin-bis
(phenanthroline), [Ag(hnc)(phen)2] using four human-derived model cell lines. In addition, selected
mechanistic studies were carried out using the most sensitive of the four cell lines. Results obtained show
that the complex could decrease the proliferation of all four cell lines including neoplastic renal and hepatic,
namely A-498 and HepG2 cells, respectively, along with two non-neoplastic renal and hepatic cell lines, HK-2
and Chang, respectively. Furthermore, non-neoplastic hepatic cells (Chang) appeared to be less sensitive to
the effect of the complex, but this effect was not replicated in the non-neoplastic renal (HK-2) cells. Based on
IC50 values [Ag(hnc)(phen)2] was shown to be almost four times more potent than cisplatin, using HepG2
cells. In addition, the observed anti-proliferative effect was shown to be both dose- and time-dependent.
Furthermore, the complex was shown to decrease DNA synthesis, but did not intercalate with it. Moreover,
there was no evidence that P-glycoprotein-mediated multi-drug resistance was likely to decrease antiproliferative
activity. Cytological stains, analysis of genomic DNA, and biochemical assays [caspase-3 and -9
and cleaved poly(ADP-ribose)-polymerase protein] showed that cell death appeared to result from apoptosis,
with the possibility of secondary necrosis. Additionally, flow cytometric analysis showed that the complex
functioned through an alteration in cell cycle progression. Taken together, [Ag(hnc)(phen)2] has been shown
to be a more potent anti-proliferative agent than cisplatin, capable of altering key biochemical events leading
to cell death. Additional mechanistic studies are underway to probe more fully its mechanism of action
Guidelines on the use of Structure from Motion Photogrammetry in Geomorphic Research
As a topographic modelling technique, structure-from-motion (SfM) photogrammetry combines the utility of digital photogrammetry with a flexibility and ease of use derived from multi-view computer vision methods. In conjunction with the rapidly increasing availability of imagery, particularly from unmanned aerial vehicles, SfM photogrammetry represents a powerful tool for geomorphological research. However, to fully realize this potential, its application must be carefully underpinned by photogrammetric considerations, surveys should be reported in sufficient detail to be repeatable (if practical) and results appropriately assessed to understand fully the potential errors involved. To deliver these goals, robust survey and reporting must be supported through (i) using appropriate survey design, (ii) applying suitable statistics to identify systematic error (bias) and to estimate precision within results, and (iii) propagating uncertainty estimates into the final data products
- …