Using Differential Equations to Model Predator-Prey Relations as Part of SCUDEM Modeling Challenge

Differential equation modeling challenges provide students with an opportunity to improve their mathematical capabilities, critical thinking skills, and communication abilities through researching and presenting on a differential equations model. This article functions to display an archetype summary of an undergraduate student team’s response to a provided prompt. Specifically, the provided mathematical model estimates how certain stimuli from a predator are accumulated to trigger a neural response in a prey. Furthermore, it tracks the propagation of the resultant action potential and the physical flight of the prey from the predator through the analysis of larval zebrafish as a model organism. This article also shares personal testimonies to highlight the benefits of these kinds of challenges for students

Development of a centrifugal microfluidic system for rapid on-site analysis of environmentally important species

Micro-total analysis systems (æTAS) have enabled the miniaturization and simplification of environmental contaminant detection methods. Reduced reagent and sample consumption, speed of analysis, and field portability are only a few of the advantages æTAS systems provide. Centrifugal microfluidics have the added advantages of using centrifugal force for moving liquids, thereby avoiding solvent and filtration problems encountered with the electroosmotic flow typically used in æTAS manifolds. These properties suggest that centrifugal æTAS systems may offer many advantages as analysis platforms for the on-site analyses of a variety of important environmental pollutants. A model instrument has been developed and characterized for rapid, classical spectrochemical reactions. The system is designed for the determination of nitrite, nitrate and hexavalent chromium, three common pollutants. The system uses a single disc that requires 100æl of sample per analyte using a centrifugal disc that filters the water sample which is then mixed with the appropriate reagents in one or two steps using capillary valves, and is detected on-disc with a pathlength of 1.04 mm. Using a multi-wavelength technique for the precise determination of the reference signal, the detection limits for these three systems are 0.008, 0.6, and 0.03 mg*L -1 for NO 2 - -N, NO 3 - -N, and Cr 6+ respectively. A comparison between this technique and several conventional techniques highlights the strengths and limitations of the system

Improved Physiology and Psychosocial Well-Being for Children with Physical Disabilities Through Virtual Reality Immersion

The purpose of this case study was to examine the physiological and psychosocial effects of an immersive virtual reality (VR) system in a female, young adult with right side paralysis following a left hemisphere brain bleed in order to determine the usefulness of immersive VR for children with physical disabilities, in particular, cerebral palsy (CP). The current study consisted of six sessions over a span of three weeks, with each session lasting approximately 45 minutes. Physiological factors (upper body mobility, heart rate variability) were assessed via a hand use questionnaire and a heart rate monitor, while psychosocial factors (e.g. positive mood) were assessed through post-session debriefing discussions with the participant. All measures were completed at each of the six VR sessions, with the exception of the hand use questionnaire, which was administered at baseline, and post-intervention. The VR programs selected were specifically chosen to engage upper body and arm movements. Descriptive analyses and coding of interviews were conducted to examine changes throughout the study sessions. The participant reported an increase in hand mobility and psychosocial well-being, such as improvement in mood, as a result of her participation in the VR sessions. The results of the current study suggest that the use of movement-specific VR programs may be beneficial to children with physical disabilities and CP, although due to the single-subject design of the study, further research is warranted

Parallel Analysis: a Method for Determining Significant Principal Components

Numerous ecological studies use Principal Components Analysis (PCA) for exploratory analysis and data reduction. Determination of the number of components to retain is the most crucial problem confronting the researcher when using PCA. An incorrect choice may lead to the underextraction of components, but commonly results in overextraction. Of several methods proposed to determine the significance of principal components, Parallel Analysis (PA) has proven consistently accurate in determining the threshold for significant components, variable loadings, and analytical statistics when decomposing a correlation matrix. In this procedure, eigenvalues from a data set prior to rotation are compared with those from a matrix of random values of the same dimensionality (p variables and n samples). PCA eigenvalues from the data greater than PA eigenvalues from the corresponding random data can be retained. All components with eigenvalues below this threshold value should be considered spurious. We illustrate Parallel Analysis on an environmental data set. We reviewed all articles utilizing PCA or Factor Analysis (FA) from 1987 to 1993 from Ecology, Ecological Monographs, Journal of Vegetation Science and Journal of Ecology. Analyses were first separated into those PCA which decomposed a correlation matrix and those PCA which decomposed a covariance matrix. Parallel Analysis (PA) was applied for each PCA/FA found in the literature. Of 39 analyses (in 22 articles), 29 (74.4%) considered no threshold rule, presumably retaining interpretable components. According to the PA results, 26 (66.7%) overextracted components. This overextraction may have resulted in potentially misleading interpretation of spurious components. It is suggested that the routine use of PA in multivariate ordination will increase confidence in the results and reduce the subjective interpretation of supposedly objective methods

Distinct transcriptional responses of mouse sensory neurons in models of human chronic pain conditions.

Background: Sensory neurons play an essential role in almost all pain conditions, and have recently been classified into distinct subsets on the basis of their transcriptomes. Here we have analysed alterations in dorsal root ganglia (DRG) gene expression using microarrays in mouse models related to human chronic pain. Methods: Six different pain models were studied in male C57BL/6J mice: (1) bone cancer pain using cancer cell injection in the intramedullary space of the femur; (2) neuropathic pain using partial sciatic nerve ligation; (3) osteoarthritis pain using mechanical joint loading; (4) chemotherapy-induced pain with oxaliplatin; (5) chronic muscle pain using hyperalgesic priming; and (6) inflammatory pain using intraplantar complete Freund's adjuvant. Microarray analyses were performed using RNA isolated from dorsal root ganglia and compared to sham/vehicle treated controls. Results: Differentially expressed genes (DEGs) were identified. Known and previously unreported genes were found to be dysregulated in each pain model. The transcriptomic profiles for each model were compared and expression profiles of DEGs within subsets of DRG neuronal populations were analysed to determine whether specific neuronal subsets could be linked to each of the pain models.  Conclusions: Each pain model exhibits a unique set of altered transcripts implying distinct cellular responses to different painful stimuli. No simple direct link between genetically distinct sets of neurons and particular pain models could be discerned

Accelerating Discovery for Complex Neurological and Behavioral Disorders Through Systems Genetics and Integrative Genomics in the Laboratory Mouse

Recent advances in systems genetics and integrative functional genomics have greatly improved the study of complex neurological and behavioral traits. The methods developed for the integrated characterization of new, high-resolution mouse genetic reference populations and systems genetics enable behavioral geneticists an unprecedented opportunity to address questions of the molecular basis of neurological and psychiatric disorders and their comorbidities. Integrative genomics augment these strategies by enabling rapid informatics-assisted candidate gene prioritization, cross-species translation, and mechanistic comparison across related disorders from a wealth of existing data in mouse and other model organisms. Ultimately, through these complementary approaches, finding the mechanisms and sources of genetic variation underlying complex neurobehavioral disease related traits is becoming tractable. Furthermore, these methods enable categorization of neurobehavioral disorders through their underlying biological basis. Together, these model organism-based approaches can lead to a refinement of diagnostic categories and targeted treatment of neurological and psychiatric disease

Complement 3a Receptor in Dorsal Horn Microglia Mediates Pronociceptive Neuropeptide Signaling

The complement 3a receptor (C3aR1) participates in microglial signaling under pathological conditions and was recently shown to be activated by the neuropeptide TLQP‐21. We previously demonstrated that TLQP‐21 elicits hyperalgesia and contributes to nerve injury‐induced hypersensitivity through an unknown mechanism in the spinal cord. Here we determined that this mechanism requires C3aR1 and that microglia are the cellular target for TLQP‐21. We propose a novel neuroimmune signaling pathway involving TLQP‐21‐induced activation of microglial C3aR1 that then contributes to spinal neuroplasticity and neuropathic pain. This unique dual‐ligand activation of C3aR1 by a neuropeptide (TLQP‐21) and an immune mediator (C3a) represents a potential broad‐spectrum mechanism throughout the CNS for integration of neuroimmune crosstalk at the molecular level

Sensory Symptom Profiles and Co-Morbidities in Painful Radiculopathy

Painful radiculopathies (RAD) and classical neuropathic pain syndromes (painful diabetic polyneuropathy, postherpetic neuralgia) show differences how the patients express their sensory perceptions. Furthermore, several clinical trials with neuropathic pain medications failed in painful radiculopathy. Epidemiological and clinical data of 2094 patients with painful radiculopathy were collected within a cross sectional survey (painDETECT) to describe demographic data and co-morbidities and to detect characteristic sensory abnormalities in patients with RAD and compare them with other neuropathic pain syndromes. Common co-morbidities in neuropathic pain (depression, sleep disturbance, anxiety) do not differ considerably between the three conditions. Compared to other neuropathic pain syndromes touch-evoked allodynia and thermal hyperalgesia are relatively uncommon in RAD. One distinct sensory symptom pattern (sensory profile), i.e., severe painful attacks and pressure induced pain in combination with mild spontaneous pain, mild mechanical allodynia and thermal hyperalgesia, was found to be characteristic for RAD. Despite similarities in sensory symptoms there are two important differences between RAD and other neuropathic pain disorders: (1) The paucity of mechanical allodynia and thermal hyperalgesia might be explained by the fact that the site of the nerve lesion in RAD is often located proximal to the dorsal root ganglion. (2) The distinct sensory profile found in RAD might be explained by compression-induced ectopic discharges from a dorsal root and not necessarily by nerve damage. These differences in pathogenesis might explain why medications effective in DPN and PHN failed to demonstrate efficacy in RAD