Pain often exists in the absence of observable injury; therefore, the gold standard for pain assessment has long been self-report. Because the inability to verbally communicate can prevent effective ...pain management, research efforts have focused on the development of a tool that accurately assesses pain without depending on self-report. Those previous efforts have not proven successful at substituting self-report with a clinically valid, physiology-based measure of pain. Recent neuroimaging data suggest that functional magnetic resonance imaging (fMRI) and support vector machine (SVM) learning can be jointly used to accurately assess cognitive states. Therefore, we hypothesized that an SVM trained on fMRI data can assess pain in the absence of self-report. In fMRI experiments, 24 individuals were presented painful and nonpainful thermal stimuli. Using eight individuals, we trained a linear SVM to distinguish these stimuli using whole-brain patterns of activity. We assessed the performance of this trained SVM model by testing it on 16 individuals whose data were not used for training. The whole-brain SVM was 81% accurate at distinguishing painful from non-painful stimuli (p<0.0000001). Using distance from the SVM hyperplane as a confidence measure, accuracy was further increased to 84%, albeit at the expense of excluding 15% of the stimuli that were the most difficult to classify. Overall performance of the SVM was primarily affected by activity in pain-processing regions of the brain including the primary somatosensory cortex, secondary somatosensory cortex, insular cortex, primary motor cortex, and cingulate cortex. Region of interest (ROI) analyses revealed that whole-brain patterns of activity led to more accurate classification than localized activity from individual brain regions. Our findings demonstrate that fMRI with SVM learning can assess pain without requiring any communication from the person being tested. We outline tasks that should be completed to advance this approach toward use in clinical settings.
Urban environments are unique because fragments of natural or semi-natural habitat are embedded within a potentially permeable matrix of human-dominated areas, creating increased landscape and, ...potentially, habitat heterogeneity. In addition, urban areas can provide diet subsidies for wildlife species in the form of fruiting ornamental plants, trash, and domestic animals. Ecological opportunity in the forms of habitat and food heterogeneity are thought to be important mechanisms in maintaining individual specialization. Identifying which contexts, traits, and mechanisms determine the success or failure of individuals within an urban wildlife population could potentially provide predictions about which populations may succeed in human-dominated landscapes and which may experience local extinction. We used both scat and stable isotope analysis of whiskers to investigate the degree to which coyotes (Canis latrans) utilized anthropogenic subsidies and exhibited individual diet specialization across the urban-rural gradient in southern California. Land use surrounding scat and isotope sample locations was also evaluated to determine the effect of land cover on diet. Human food constituted a significant portion of urban coyote diet (22% of scats, 38% of diet estimated by stable isotope analysis). Domestic cats (Felis catus) and ornamental fruit and seeds were also important items in urban coyote diets. Consumption of anthropogenic items decreased with decreasing urbanization. In suburban areas, seasonality influenced the frequency of occurrence of anthropogenic subsidies with increased consumption in the dry season. The amount of altered open space (areas such as golf courses, cemeteries, and landscaped parks) nearby had a negative effect on the consumption of anthropogenic items in both urban and suburban areas. Contrary to our hypothesis, urban coyotes displayed reduced between-individual variation compared to suburban and rural coyotes. It is possible that the core urban areas of cities are so densely developed and subsidized that wildlife inhabiting these areas actually have reduced ecological opportunity. Suburban animals had the broadest isotopic niches and maintained similar individual specialization to rural coyotes. Wildlife in suburban areas still have access to relatively undisturbed natural areas while being able to take advantage of anthropogenic subsidies in neighboring residential areas. Therefore, areas with intermediate urban development may be associated with increased ecological opportunity and specialization.
A region of a star that is stable to convection according to the Ledoux criterion may nevertheless undergo additional mixing if the mean molecular weight increases with radius. This process is called ...fingering (thermohaline) convection and may account for some of the unexplained mixing in stars such as those that have been polluted by planetary infall and those burning super(3)He. We propose a new model for mixing by fingering convection in the parameter regime relevant for stellar (and planetary) interiors. Our theory is based on physical principles and supported by three-dimensional direct numerical simulations. We also discuss the possibility of formation of thermocompositional staircases in fingering regions, and their role in enhancing mixing. Finally, we provide a simple algorithm to implement this theory in one-dimensional stellar codes, such as KEPLER and MESA.
ABSTRACT Nucleosynthesis, light curves, explosion energies, and remnant masses are calculated for a grid of supernovae (SNe) resulting from massive stars with solar metallicity and masses from 9.0 to ...120 M ⊙ . The full evolution is followed using an adaptive reaction network of up to 2000 nuclei. A novel aspect of the survey is the use of a one-dimensional neutrino transport model for the explosion. This explosion model has been calibrated to give the observed energy for SN 1987A, using five standard progenitors, and for the Crab SN using a 9.6 M ⊙ progenitor. As a result of using a calibrated central engine, the final kinetic energy of the SN is variable and sensitive to the structure of each pre-SN star. Many progenitors with extended core structures do not explode, but become black holes (BHs), and the masses of exploding stars do not form a simply connected set. The resulting nucleosynthesis agrees reasonably well with the Sun provided that a reasonable contribution from SNe Ia is also allowed, but with a deficiency of light s-process isotopes. The resulting neutron star initial mass function has a mean gravitational mass near 1.4 M ⊙ . The average BH mass is about 9 M ⊙ if only the helium core implodes, and 14 M ⊙ if the entire pre-SN star collapses. Only ∼10% of SNe come from stars over 20 M ⊙ , and some of these are Type Ib or Ic. Some useful systematics of Type IIp light curves are explored.
Polymeric nanoparticles: the future of nanomedicine Banik, Brittany L.; Fattahi, Pouria; Brown, Justin L.
Wiley interdisciplinary reviews. Nanomedicine and nanobiotechnology,
March/April 2016, Letnik:
8, Številka:
2
Journal Article
Recenzirano
Polymeric nanoparticles (NPs) are one of the most studied organic strategies for nanomedicine. Intense interest lies in the potential of polymeric NPs to revolutionize modern medicine. To determine ...the ideal nanosystem for more effective and distinctly targeted delivery of therapeutic applications, particle size, morphology, material choice, and processing techniques are all research areas of interest. Utilizations of polymeric NPs include drug delivery techniques such as conjugation and entrapment of drugs, prodrugs, stimuli‐responsive systems, imaging modalities, and theranostics. Cancer, neurodegenerative disorders, and cardiovascular diseases are fields impacted by NP technologies that push scientific boundaries to the leading edge of transformative advances for nanomedicine. WIREs Nanomed Nanobiotechnol 2016, 8:271–299. doi: 10.1002/wnan.1364
This article is categorized under:
Therapeutic Approaches and Drug Discovery > Emerging Technologies
Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Disruption of Arctic Staircases by Shear Brown, Justin M.; Radko, Timour
Geophysical research letters,
28 October 2022, Letnik:
49, Številka:
20
Journal Article
Recenzirano
Odprti dostop
Though thermohaline staircases exist in a large fraction of the Arctic halocline, the interactions of such staircases with shear and turbulence are still largely unexplored. We perform a series of ...three‐dimensional Direct Numerical Simulations with and without shear and demonstrate the capacity of shear to disrupt Arctic staircases. We force an oscillating shear throughout the domain in order to represent the effects of passing internal waves of wavelengths much larger than the simulated domain. Shear is shown to disrupt staircases when the Richardson number falls below 1/4 for small layer heights (0.5 m thick), but larger layers (1 m thick) are more resistant. We determine the presence and strength of the layers using measures of steppiness from the literature, finding that a metric based on the rms temperature gradient proves most accurate. This work demonstrates that double‐diffusive interfaces can be surprisingly robust, sometimes even maintaining their structure in strong, dynamically unstable shears.
Plain Language Summary
In the Arctic, there exists a large mass of relatively warm water that originates from the Atlantic Ocean. Near the top of this watermass, where the temperature decreases rapidly, stacks of layers are present, each about 1–3 m tall, within which temperature and salinity are uniform. These peculiar structures are known as “staircases,” and they tend to form in regions that are deep enough that these layers are shielded from the near‐surface ocean turbulence. Because they exist above the warmer water of Atlantic origin and below the cooler water below the sea ice, the heat fluxes through them affect the rate at which heat from the Atlantic water propagates upward. Once this heat passes through these staircases, it inevitably reaches the sea ice and promotes sea‐ice melt. Thus, staircases serve as a gatekeeper protecting the sea ice from the warm water of Atlantic origin. We investigate the sensitivity of these structures to destruction by common wave‐induced motions.
Key Points
We establish conditions for the disruption of staircases by strong vertical shear associated with internal waves
Thin layers are more easily disrupted by shear than thick ones
We evaluate the efficacy of previous steppiness metrics, finding that the rms temperature gradient yields accurate results
Spinal cord injury (SCI) often results in devastating effects on function and quality of life. The majority of SCIs occur in the cervical region with restoration of arm and hand function being the ...highest priority by patients. Current restoration strategies rely on maximizing and optimally redistributing residual muscle functions that remain under volitional control. The polio epidemic and World Wars led to the development and refinement of tendon transfers, which has long been the standard reconstructive approach for the upper extremity following SCI. However, the past few decades has seen the emergence of nerve transfers from a “salvage” procedure for the management of peripheral nerve injuries, to a powerful reconstructive tool following SCI. Nerve transfers offer distinct advantages over tendon transfers; however, optimal functional recovery frequently benefits from a multi-modality approach and must be tailored to specific injury patterns. Extension of nerve transfers to the lower body presents additional hurdles such as limited donor nerve sources and much longer target distances.
In this review, we will discuss the evolution of nerve transfers for upper extremity reanimation following cervical SCI and discuss advantages over tendon transfers. We will address the progress for nerve transfers to restore lower body function, including ambulation and bladder control. Finally, we will address future efforts in the field. Reconstructive modalities, including nerve and tendon transfers, remain underutilized following SCI and it is important that these therapeutic options are made known to the research community, medical providers, and patients.
•Nerve transfers are a powerful intervention for functional recovery following spinal cord injury.•Comparison of nerve versus tendon transfers.•Role for nerve transfers in the lower body.•Future strategies to enhance nerve transfer approaches.
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