Case report: MR spectroscopy in pantothenate kinase-2 associated neurodegeneration

We report a case of a 13-year-old girl with Hallervorden-Spatz disease (HSD) or pantothenate kinase-2 associated neurodegeneration (PKAN). HSD is a rare neurodegenerative disorder, which is characterized by a rapidly progressive extrapyramidal syndrome, dementia with optic atrophy, and retinal degeneration. It is associated with accumulation of cysteine-iron complex in the globus pallidi and substantia nigra. The MRI "eye of the tiger" sign is the characteristic. MRI spectroscopy is also characteristic. It shows markedly decreased NAA/Cr values in the globus pallidi and substantia nigra with increased mI/Cr values that suggest of gliosis

Case report: MR spectroscopy in pantothenate kinase-2 associated neurodegeneration

We report a case of a 13-year-old girl with Hallervorden-Spatz disease (HSD) or pantothenate kinase-2 associated neurodegeneration (PKAN). HSD is a rare neurodegenerative disorder, which is characterized by a rapidly progressive extrapyramidal syndrome, dementia with optic atrophy, and retinal degeneration. It is associated with accumulation of cysteine-iron complex in the globus pallidi and substantia nigra. The MRI “eye of the tiger” sign is the characteristic. MRI spectroscopy is also characteristic. It shows markedly decreased NAA/Cr values in the globus pallidi and substantia nigra with increased mI/Cr values that suggest of gliosis

Fish community diversity assessment of protected Saraiyaman wetland in the Ganga River basin, India

‘Saraiyaman’ along Gandak River in the Ganges basin is a protected natural oxbow lake. In spite of the protection mecha- nism, it has been unrecognised for its habitat services to the fish community by resource managers and local dwellers. To investigate fish diversity and habitat status of Saraiyaman, exploratory surveys were conducted from April 2017 to March 2021. The analysis resulted in distribution of 58 fish species belonging to 7 orders, 20 families and 40 genera. Cypriniformes was found as the most dominant order. Out of 58 species, 7 were evaluated under Near Threatened (NT) category. The high value of Shannon diversity index (H’ = 3.50) highlighted significance of habitat offered by Saraiyaman for diverse fish spe- cies and its potential to serve as a gene pool for conservation of endemic and threatened fish species of the Ganga basin. The loss of Saraiyaman’s connection from River Gandak, increasing encroachment by cropland and climate change have resulted in water level reduction, water area shrinkage, eutrophication, infestation of aquatic weeds, degradation in habitat condition for fish community, decline in fish population, especially vulnerable catfish Wallago attu, and lack of quality fish brooders. Hence, under influence of multiple stressors, Saraiyaman is leading towards marsh and land afterwards. The baseline information generated on habitat and fish diversity status and management measures suggested in the present study will help in restoration of the function and services of Saraiyaman through existing protection mechanism by ensuring the conservation and sustainable resource utilisation for achieving the wetland-associated CBD-Sustainable Development Goals

Electrical Properties of Thiol-ene-based Shape Memory Polymers Intended for Flexible Electronics

Thiol-ene/acrylate-based shape memory polymers (SMPs) with tunable mechanical and thermomechanical properties are promising substrate materials for flexible electronics applications. These UV-curable polymer compositions can easily be polymerized onto pre-fabricated electronic components and can be molded into desired geometries to provide a shape-changing behavior or a tunable softness. Alternatively, SMPs may be prepared as a flat substrate, and electronic circuitry may be built directly on top by thin film processing technologies. Whichever way the final structure is produced, the operation of electronic circuits will be influenced by the electrical and mechanical properties of the underlying (and sometimes also encapsulating) SMP substrate. Here, we present electronic properties, such as permittivity and resistivity of a typical SMP composition that has a low glass transition temperature (between 40 and 60 °C dependent on the curing process) in different thermomechanical states of polymer. We fabricated parallel plate capacitors from a previously reported SMP composition (fully softening (FS)-SMP) using two different curing processes, and then we determined the electrical properties of relative permittivity and resistivity below and above the glass transition temperature. Our data shows that the curing process influenced the electrical permittivity, but not the electrical resistivity. Corona-Kelvin metrology evaluated the quality of the surface of FS-SMP spun on the wafer. Overall, FS-SMP demonstrates resistivity appropriate for use as an insulating material

Chronic Intracortical Recording and Electrochemical Stability of Thiol-ene/Acrylate Shape Memory Polymer Electrode Arrays

Current intracortical probe technology is limited in clinical implementation due to the short functional lifetime of implanted devices. Devices often fail several months to years post-implantation, likely due to the chronic immune response characterized by glial scarring and neuronal dieback. It has been demonstrated that this neuroinflammatory response is influenced by the mechanical mismatch between stiff devices and the soft brain tissue, spurring interest in the use of softer polymer materials for probe encapsulation. Here, we demonstrate stable recordings and electrochemical properties obtained from fully encapsulated shape memory polymer (SMP) intracortical electrodes implanted in the rat motor cortex for 13 weeks. SMPs are a class of material that exhibit modulus changes when exposed to specific conditions. The formulation used in these devices softens by an order of magnitude after implantation compared to its dry, room-temperature modulus of ~2 GPa

Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes

Thiol-ene based shape memory polymers (SMPs) have been developed for use as intracortical microelectrode substrates. The unique chemistry provides precise control over the mechanical and thermal glass-transition properties. As a result, SMP substrates are stiff at room temperature, allowing for insertion into the brain without buckling and subsequently soften in response to body temperatures, reducing the mechanical mismatch between device and tissue. Since the surface chemistry of the materials can contribute significantly to the ultimate biocompatibility, as a first step in the characterization of our SMPs, we sought to isolate the biological response to the implanted material surface without regards to the softening mechanics. To accomplish this, we tightly controlled for bulk stiffness by comparing bare silicon ‘dummy’ devices to thickness-matched silicon devices dip-coated with SMP. The neuroinflammatory response was evaluated after devices were implanted in the rat cortex for 2 or 16 weeks. We observed no differences in the markers tested at either time point, except that astrocytic scarring was significantly reduced for the dip-coated implants at 16 weeks. The surface properties of non-softening thiol-ene SMP substrates appeared to be equally-tolerated and just as suitable as silicon for neural implant substrates for applications such as intracortical microelectrodes, laying the groundwork for future softer devices to improve upon the prototype device performance presented here