The effects of chronic neural implantation on localized vasculature

Prosthetic solutions currently available range from simple devices intended for aesthetics purposes to complex systems attempting to restore lost function and sensation; of these methods, none show more promise in restoration of normal function and life satisfaction than neural prosthetics. These devices directly interface with the nervous system in order to restore realistic function and feeling to the patient, potentially returning them to how their life once was. While in some cases patients requiring prosthetics can utilize peripheral nerves, those who suffer from injuries or disease which cause damage to the central nervous system can necessitate the usage of devices implanted directly into the brain or spinal cord. Research has shown that these implants lose efficacy over time due to the immunological reaction of the brain to injury, mirroring the foreign body response occurring in the rest of the body; these devices become encapsulated by scar tissue and local cells die or migrate over time. Outside of the response of cells like microglia and astrocytes to the injury, there is another factor influencing how the brain responds to injury: the vascular response. Previous experiments have shown the presence of visible vasospasms during and after implantation, as well as potential vasoconstriction in chronically implanted animals. As the vascular response can influence the survival of nearby cells as well as portions of the immunological response, as evidenced by stroke, Reversible cerebral vasoconstriction syndrome (RVCS), and other disorders which occur due to vascular abnormalities, understanding how local vasculature responds to chronic implantation is an important step in developing methods to maintain function for chronically implanted devices. ^ In order to quantify this response, we implanted shank electrodes into 12 animals and then sacrificed them at separate time points that already have a well characterized immunological response. The brains extracted from these animals were then sliced in order to capture the implant intact and stained to allow for confocal imaging. These images were then cleaned and post-processed to extract information on the blood vessels present, allowing for the quantification of vascular segment diameter and length. Our resulting data shows that local vasodilation occurs almost immediately following the initial implantation, and is still occurring at 7 days afterward. Furthermore, our data suggests that there is a degree of systemic vasodilation, as over the course of 7 days we find an increase in the vascular diameter present in the opposite hemisphere where no injury has occurred

Discrete model for laser driven etching and microstructuring of metallic surfaces

We present a unidimensional discrete solid-on-solid model evolving in time using a kinetic Monte Carlo method to simulate micro-structuring of kerfs on metallic surfaces by means of laser-induced jet-chemical etching. The precise control of the passivation layer achieved by this technique is responsible for the high resolution of the structures. However, within a certain range of experimental parameters, the microstructuring of kerfs on stainless steel surfaces with a solution of $\mathrm{H}_3\mathrm{PO}_4$ shows periodic ripples, which are considered to originate from an intrinsic dynamics. The model mimics a few of the various physical and chemical processes involved and within certain parameter ranges reproduces some morphological aspects of the structures, in particular ripple regimes. We analyze the range of values of laser beam power for the appearance of ripples in both experimental and simulated kerfs. The discrete model is an extension of one that has been used previously in the context of ion sputtering and is related to a noisy version of the Kuramoto-Sivashinsky equation used extensively in the field of pattern formation.Comment: Revised version. Etching probability distribution and new simulations adde

Process mapping of laser surface modification of AISI 316L stainless steel for biomedical applications

A 1.5-kW CO2 laser in pulsed mode at 3 kHz was used to investigate the effects of varied laser process parameters and resulting morphology of AISI 316L stainless steel. Irradiance and residence time were varied between 7.9 to 23.6 MW/cm2 and 50 to 167 µs respectively. A strong correlation between irradiance, residence time, depth of processing and roughness of processed steel was established. The high depth of altered microstructure and increased roughness were linked to higher levels of both irradiance and residence times. Energy fluence and surface temperature models were used to predict levels of melting occurring on the surface through the analysis of roughness and depth of the region processed. Microstructural images captured by the SEM revealed significant grain structure changes at higher irradiances, but due to increased residence times, limited to the laser in use, the hardness values were not improved

Molecular Phylogeny of the Genus Lolliguncula Steenstrup, 1881 Based on Nuclear and Mitochondrial DNA Sequences Indicates Genetic Isolation of Populations from North and South Atlantic, and the Possible Presence of Further Cryptic Species

Squid of the genus Lolliguncula Steenstrup, 1881 are small bodied, coastal species capable of tolerating low salinity. Lolliguncula sp. are found exclusively in the New World, although only one of the four recognized species (Lolliguncula brevis) occurs in the Atlantic Ocean. Preliminary morphological analyses suggest that Lolliguncula brevis populations in the North and South Atlantic may represent distinct species. The principal objective of the present study was to verify the phylogenetic relationships within the genus and test for the presence of possible cryptic species. Both gene and species tree topologies indicated that Lolliguncula brevis specimens from the North and South Atlantic represent distinct phylogenetic clades. In contrast with previous studies, L. panamensis was identified as the basal species of the genus. Our results provide important insights into the phylogenetic relationships among the Lolliguncula specimens analyzed, and confirm the genetic separation of Lolliguncula brevis populations of the North and South Atlantic at the level of sister species

A Mild and Efficient Synthesis of Oxindoles: Progress Towards the Synthesis of Welwitindolinone A Isonitrile

The complete carbon skeleton of welwitindolinone A isonitrile has been prepared by using a [2+2] cycloaddition to establish the bicyclo[4.2.0]octane core and a SmI2-mediated intramolecular reductive cyclization between an enone and an aryl isocyanate to stereoselectively install the spiro-oxindole (see scheme; DBU=1,8-diazabicyclo[5.4.0]undec-7-ene)

Environmental Influences on Fish Species Distribution in the Musolo River System, Congo River Basin (Democratic Republic of the Congo, Central Africa)

Ichthyofaunal distribution was studied in the Musolo River system, a small affluent tributary of the Congo River flowing into Pool Malebo (Democratic Republic of the Congo). Twelve ecological stations were sampled, of which eight were located in the Musolo main-channel and four in the Fushi River, a principal tributary of the Musolo. Each station was sampled four times over a two-year period, with fishing techniques following standardized methods utilizing dip and cast nets, and nine environment variables were measured at each station. Fifty-three fish species belonging to 36 genera and 16 families were collected with the Alestidae, Distichodontidae, Cichlidae, Cyprinidae, Mormyridae, and Mochokidae being the most diversified. Redundancy Analysis with forward selection coupled with Monte Carlo permutation tests (499 permutations) identified total dissolved solid (25.8%) and altitude (24.4%) as accounting for 50.2% of total variance (p < 0.05). The contribution of the two first axes was significant (F = 3.41; p = 0.004). Species richness increases from upstream to downstream. In general, the high value of Shannon’s diversity (1.07-2.67) and Equitability European Scientific Journal November 2019 edition Vol.15, No.33 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431 193 (0.62-0.96) indices at all sites, indicates that the examined stretch of the Musolo River system is in good ecological health, despite its location adjacent to the megacity of Kinshasa

HDQLIFE and neuro‐QoL physical function measures: Responsiveness in persons with huntington’s disease

BackgroundHuntington’s disease (HD) is a neurological disorder that causes severe motor symptoms that adversely impact health‐related quality of life. Patient‐reported physical function outcome measures in HD have shown cross‐sectional evidence of validity, but responsiveness has not yet been assessed.ObjectivesThis study evaluates the responsiveness of the Huntington Disease Health‐Related Quality of Life (HDQLIFE) and the Quality of Life in Neurological Disorders (Neuro‐QoL) physical function measures in persons with HD.MethodsA total of 347 participants completed baseline and at least 1 follow‐up (12‐month and 24‐month) measure (HDQLIFE Chorea, HDQLIFE Swallowing Difficulties, HDQLIFE Speech Difficulties, Neuro‐QoL Upper Extremity Function, and/or Neuro‐QoL Lower Extremity Function). Of the participants that completed the baseline assessment, 338 (90.9%) completed the 12‐month assessment, and 293 (78.8%) completed the 24‐month assessment. Standardized response means and general linear models evaluated whether the physical function measures were responsive to self‐reported and clinician‐rated change over time.ResultsSmall to moderate effect sizes for the standardized response means supported 12‐month and 24‐month responsiveness of the HDQLIFE and Neuro‐QoL measures for those with either self‐reported or clinician‐rated declines in function. General linear models supported 12‐month and 24‐month responsiveness for all HRQOL measures relative to self‐reported declines in health, but generally only 24‐month responsiveness was supported relative to clinician‐rated declines in function.ConclusionsLongitudinal analyses indicate that the HDQLIFE and the Neuro‐QoL physical function measures are sensitive to change over time in individuals with HD. Thus, these scales exhibit evidence of responsiveness and may be useful outcome measures in future clinical trials. © 2019 International Parkinson and Movement Disorder SocietyPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154235/1/mds27908_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154235/2/mds27908.pd