33,665 research outputs found
Visual and Contextual Modeling for the Detection of Repeated Mild Traumatic Brain Injury.
Currently, there is a lack of computational methods for the evaluation of mild traumatic brain injury (mTBI) from magnetic resonance imaging (MRI). Further, the development of automated analyses has been hindered by the subtle nature of mTBI abnormalities, which appear as low contrast MR regions. This paper proposes an approach that is able to detect mTBI lesions by combining both the high-level context and low-level visual information. The contextual model estimates the progression of the disease using subject information, such as the time since injury and the knowledge about the location of mTBI. The visual model utilizes texture features in MRI along with a probabilistic support vector machine to maximize the discrimination in unimodal MR images. These two models are fused to obtain a final estimate of the locations of the mTBI lesion. The models are tested using a novel rodent model of repeated mTBI dataset. The experimental results demonstrate that the fusion of both contextual and visual textural features outperforms other state-of-the-art approaches. Clinically, our approach has the potential to benefit both clinicians by speeding diagnosis and patients by improving clinical care
Evidence to Suggest That Teeth Act as Human Ornament Displays Signalling Mate Quality
Ornament displays seen in animals convey information about genetic quality, developmental history and current disease state to both prospective sexual partners and potential rivals. In this context, showing of teeth through smiles etc is a characteristic feature of human social interaction. Tooth development is influenced by genetic and environmental factors. Adult teeth record environmental and traumatic events, as well as the effects of disease and ageing. Teeth are therefore a rich source of information about individuals and their histories. This study examined the effects of digital manipulations of tooth colour and spacing. Results showed that deviation away from normal spacing and/or the presence of yellowed colouration had negative effects on ratings of attractiveness and that these effects were markedly stronger in female models. Whitening had no effect beyond that produced by natural colouration. This indicates that these colour induced alterations in ratings of attractiveness are mediated by increased/decreased yellowing rather than whitening per se. Teeth become yellower and darker with age. Therefore it is suggested that whilst the teeth of both sexes act as human ornament displays, the female display is more complex because it additionally signals residual reproductive value
Agent-based modeling: a systematic assessment of use cases and requirements for enhancing pharmaceutical research and development productivity.
A crisis continues to brew within the pharmaceutical research and development (R&D) enterprise: productivity continues declining as costs rise, despite ongoing, often dramatic scientific and technical advances. To reverse this trend, we offer various suggestions for both the expansion and broader adoption of modeling and simulation (M&S) methods. We suggest strategies and scenarios intended to enable new M&S use cases that directly engage R&D knowledge generation and build actionable mechanistic insight, thereby opening the door to enhanced productivity. What M&S requirements must be satisfied to access and open the door, and begin reversing the productivity decline? Can current methods and tools fulfill the requirements, or are new methods necessary? We draw on the relevant, recent literature to provide and explore answers. In so doing, we identify essential, key roles for agent-based and other methods. We assemble a list of requirements necessary for M&S to meet the diverse needs distilled from a collection of research, review, and opinion articles. We argue that to realize its full potential, M&S should be actualized within a larger information technology framework--a dynamic knowledge repository--wherein models of various types execute, evolve, and increase in accuracy over time. We offer some details of the issues that must be addressed for such a repository to accrue the capabilities needed to reverse the productivity decline
Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 274)
This bibliography lists 128 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1985
Recommended from our members
Immunosuppressive effect and global dysregulation of blood transcriptome in response to psychosocial stress in vervet monkeys (Chlorocebus sabaeus).
Psychosocial stressors - life events that challenge social support and relationships - represent powerful risk factors for human disease; included amongst these events are relocation, isolation and displacement. To evaluate the impact of a controlled psychosocial stressor on physiology and underlying molecular pathways, we longitudinally studied the influence of a 28-day period of quarantine on biomarkers of immune signalling, microbial translocation, glycaemic health and blood transcriptome in the wild-born vervet monkey. This event caused a coordinated, mostly transient, reduction of circulating levels of nine immune signalling molecules. These were paralleled by a massive dysregulation of blood transcriptome, including genes implicated in chronic pathologies and immune functions. Immune and inflammatory functions were enriched among the genes downregulated in response to stress. An upregulation of genes involved in blood coagulation, platelet activation was characteristic of the rapid response to stress induction. Stress also decreased neutrophils and increased CD4 + T cell proportions in blood. This model of psychosocial stress, characterised by an immune dysregulation at the transcriptomic, molecular and cellular levels, creates opportunities to uncover the underlying mechanisms of stress-related diseases with an immune component, including cardiovascular diseases and susceptibility to infections
Characterization studies of Silicon Photomultipliers and crystals matrices for a novel time of flight PET detector
This paper describes the characterization of crystal matrices and silicon
photomultiplier arrays for a novel Positron Emission Tomography (PET) detector,
namely the external plate of the EndoTOFPET-US system. The EndoTOFPET-US
collaboration aims to integrate Time-Of-Flight PET with ultrasound endoscopy in
a novel multimodal device, capable to support the development of new biomarkers
for prostate and pancreatic tumors. The detector consists in two parts: a PET
head mounted on an ultrasound probe and an external PET plate. The challenging
goal of 1 mm spatial resolution for the PET image requires a detector with
small crystal size, and therefore high channel density: 4096 LYSO crystals
individually readout by Silicon Photomultipliers (SiPM) make up the external
plate. The quality and properties of these components must be assessed before
the assembly. The dark count rate, gain, breakdown voltage and correlated noise
of the SiPMs are measured, while the LYSO crystals are evaluated in terms of
light yield and energy resolution. In order to effectively reduce the noise in
the PET image, high time resolution for the gamma detection is mandatory. The
Coincidence Time Resolution (CTR) of all the SiPMs assembled with crystals is
measured, and results show a value close to the demanding goal of 200 ps FWHM.
The light output is evaluated for every channel for a preliminary detector
calibration, showing an average of about 1800 pixels fired on the SiPM for a
511 keV interaction. Finally, the average energy resolution at 511 keV is about
13 %, enough for effective Compton rejection.Comment: 12 pages, 31 figure
- …