Defining Multi-Scale Relationships Between Biomechanics & Neuronal Dysfunction In Ligament Pain Using Integrated Experimental & Computational Approaches

Capsular ligaments can encode the mechanical state of joints owing to their innervation. For example, the spinal facet capsular ligament that encloses the facet joint is innervated by mechanoreceptors and nociceptors, and is a major source of neck and low back pain from aberrant spinal motions. The cervical facet capsule is commonly injured by its excessive stretch during neck trauma. Although supraphysiologic deformation of the facet capsular ligament can activate its afferents and induce pain, the local biomechanical and neuronal mechanisms underlying sensory transduction for pain from mechanical inputs remain unclear. The studies in this thesis use integrated in vitro, in vivo and in silico methods to investigate the interplay between the mechanical and nociceptive functions of the cervical facet capsular ligament. Tissue-level mechanics, collagen network restructuring and neuronal dysfunction are all assessed across length scales using a neuron collagen construct (NCC) system as well as animal and computational modeling. Afferent activation, nociception and dysfunction are found to depend on the macro-scale tissue strains. Yet, relationships between macroscopic stretch and micro-scale pathophysiology in the facet capsule is confounded by its heterogeneous fibrous architecture. Studies in this thesis show that localized collagen disorganization is associated with excessive network-level reorganization and fiber-level stretch using network analysis and finite element-based modeling. Integrated imaging of the extracellular matrix structure and neuronal dysfunction in the NCC system provides evidence for collagen network organization and local fiber kinematics as mediators of pain-related neuronal signaling. Stretch-induced production of nociceptive neuropeptides in NCCs is prevented by inhibiting collagen-binding integrins, supporting a role of cell-matrix adhesion in converting noxious mechanical stimuli in to pain signals. Further, neuronal mechanotransduction that initiates pain is found to involve the intracellular RhoA/Rho kinase ROCK. In vivo studies in the rat suggest that intra-articular ROCK likely contributes to the development of central sensitization and facet joint pain, possibly via neuropeptide-mediated synaptic transmission and spinal microglial activation. Collectively, these findings establish the role of collagen networks and fibers in translating macroscopic ligament stretch in to neuronal pain signals and identify mechanotransductive signaling cascades that have clinical relevance as possible treatment for trauma-induced facet pain

A cross-cultural comparison of school disciplinary climate between Asia and North America using a large-scale international dataset and Rasch measurement theory

School disciplinary climate influences student outcomes. As a result, examining differences in principals’ perceptions of disciplinary climate within and across countries and regions may shed some light on decreasing achievement gaps. The quantitative study examined how principals from different geographical locations perceive school disciplinary climate differently with a subset sample obtained from the Progress in International Reading Literacy Study (PIRLS) 2021 package. School disciplinary climate was measured using the School Discipline and Safety subscale from the School Questionnaire. Results suggested that there existed statistically significant differences in the difficulty ordering of school disciplinary climate across regions, and these differences were more pronounced between the two continents

Optimal Sensor Collaboration for Parameter Tracking Using Energy Harvesting Sensors

In this paper, we design an optimal sensor collaboration strategy among neighboring nodes while tracking a time-varying parameter using wireless sensor networks in the presence of imperfect communication channels. The sensor network is assumed to be self-powered, where sensors are equipped with energy harvesters that replenish energy from the environment. In order to minimize the mean square estimation error of parameter tracking, we propose an online sensor collaboration policy subject to real-time energy harvesting constraints. The proposed energy allocation strategy is computationally light and only relies on the second-order statistics of the system parameters. For this, we first consider an offline non-convex optimization problem, which is solved exactly using semidefinite programming. Based on the offline solution, we design an online power allocation policy that requires minimal online computation and satisfies the dynamics of energy flow at each sensor. We prove that the proposed online policy is asymptotically equivalent to the optimal offline solution and show its convergence rate and robustness. We empirically show that the estimation performance of the proposed online scheme is better than that of the online scheme when channel state information about the dynamical system is available in the low SNR regime. Numerical results are conducted to demonstrate the effectiveness of our approach

The double contravariant powerset monad in the Goguen category of fuzzy sets

A monad is constructed in the Goguen category of fuzzy sets valued in a unital quantale, which is an analog of the double contravariant powerset monad in the category of sets. With help of this monad it is proved that the Goguen category of fuzzy sets is dually monadic over itself.Comment: 21 page

Fractal Metamaterial Absorber with Three-Order Oblique Cross Dipole Slot Structure and its Application for In-band RCS Reduction of Array Antennas

To miniaturize the perfect metamaterial absorber, a fractal three-order oblique cross dipole slot structure is proposed and investigated in this paper. The fractal perfect metamaterial absorber (FPMA) consists of two metallic layers separated by a lossy dielectric substrate. The top layer etched a three-order oblique fractal-shaped cross dipole slot set in a square patch and the bottom one is a solid metal. The parametric study is performed for providing practical design guidelines. A prototype with a thickness of 0.0106λ (λ is the wavelength at 3.18 GHz) of the FPMA was designed, fabricated, measured, and is loaded on a 1×10 guidewave slot array antennas to reduce the in-band radar cross section (RCS) based on their surface current distribution. Experiments are carried out to verify the simulation results, and the experimental results show that the absorption at normal incidence is above 90% from 3.17 to 3.22GHz, the size for the absorber is 0.1λ×0.1λ, the three-order FPMA is miniaturized 60% compared with the zero-order ones, and the array antennas significantly obtain the RCS reduction without the radiation deterioration