Brainstem neurochemical profiles after hospitalisation for COVID-19: a 7T MR spectroscopy study

BackgroundSomatic, cognitive and mental health issues have been identified in three-quarters of people 5 months after hospitalisation for severe acute SARS-CoV-2 (COVID-19) infection. The underlying neuroanatomical basis of these symptoms remains unclear, but recent studies suggest a role for altered brainstem physiology. We aimed to test the hypothesis that brainstem neurochemical profiles differ in patients who had been hospitalised for COVID-19 compared to matched controls using 7T magnetic resonance spectroscopy (MRS).MethodsThis prospective case–control study recruited 34 individuals who were hospitalised for COVID-19 and 15 healthy controls with no history of COVID-19 infection from two major UK hospitals before vaccines became available. The participants underwent 7T semi-adiabatic localization by adiabatic selective refocusing (sLASER) 1H-MRS at the ponto-medullary junction. Water-referenced metabolite concentrations were compared between the patients and controls and correlated with infection severity, as measured by maximum C-reactive protein (CRPmax) assay during inpatient admission. Linear mixed modelling was used with a 0.05 significance level.ResultsSpectral quality was high/acceptable in 44/49 participants according to the MRS Consensus criteria. The magnitude of inflammation during patient admission (i.e., CRPmax) correlated positively with myo-inositol concentration (β = 0.005, p = 0.035), as did patient-reported symptoms (β = −0.564, p = 0.023). However, metabolite concentrations were not significantly different between the patients and controls.ConclusionWe show the feasibility of assessing brainstem neurochemical profiles using 7T 1H-MRS in a multi-centre study. Technical limitations at one site’s 7T MRI led to variable repetition times, which limited our statistical power and should be avoided in future studies. Our findings highlight the need for further investigation into the role of neuroinflammation in post-acute COVID-19

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Enhanced biological N2 fixation and yield of faba bean ('Vicia faba' L.) in an acid soil following biochar addition: dissection of causal mechanisms

Background and aims Acid soils constrain legume growth and biochars have been shown to address these constraints and enhance biological N₂ fixation in glasshouse studies. A dissection of causal mechanisms from multiple crop field studies is lacking. Methods In a sub-tropical field study, faba bean ('Vicia faba' L.) was cultivated in rotation with corn ('Zea mays') following amendment of two contrasting biochars, compost and lime in a rhodic ferralsol. Key soil parameters and plant nutrient uptake were investigated alongside stable ¹⁵N isotope methodologies to elucidate the causal mechanisms for enhanced biological N₂ fixation and crop productivity. Results Biological N₂ fixation was associated with plant Mo uptake, which was driven by reductions in soil acidity following lime and papermill (PM) biochar amendment. In contrast, crop yield was associated with plant P and B uptake, and amelioration of soil pH constraints. These were most effectively ameliorated by PM biochar as it addressed both pH constraints and low soil nutrient status. Conclusions While liming resulted in the highest biological N₂ fixation, biochars provided greater benefits to faba bean yield by addressing P nutrition and ameliorating Al toxicity

Enhanced biological N2 fixation and yield of faba bean (Vicia faba L.) in an acid soil following biochar addition: dissection of causal mechanisms

Background and aims Acid soils constrain legume growth and biochars have been shown to address these constraints and enhance biological N2 fixation in glasshouse studies. A dissection of causal mechanisms from multiple crop field studies is lacking. Methods In a sub-tropical field study, faba bean (Vicia faba L.) was cultivated in rotation with corn (Zea mays) following amendment of two contrasting biochars, compost and lime in a rhodic ferralsol. Key soil parameters and plant nutrient uptake were investigated alongside stable 15N isotope methodologies to elucidate the causal mechanisms for enhanced biological N2 fixation and crop productivity. Results Biological N2 fixation was associated with plant Mo uptake, which was driven by reductions in soil acidity following lime and papermill (PM) biochar amendment. In contrast, crop yield was associated with plant P and B uptake, and amelioration of soil pH constraints. These were most effectively ameliorated by PM biochar as it addressed both pH constraints and low soil nutrient status. Conclusions While liming resulted in the highest biological N2 fixation, biochars provided greater benefits to faba bean yield by addressing P nutrition and ameliorating Al toxicity

Biochar improves diary pasture yields by alleviating P and K constraints with no influence on soil respiration or N2O emissions

Dairy pastures can be a major source of soil nitrous oxide (N2O) emissions due to the combination of intensive nitrogen (N) fertiliser use and high soil water content, from either rainfall and/or irrigation. Biochar application is a promising approach to lower soil greenhouse gas emissions, particularly under high soil moisture conditions where denitrification is the primary N-transformation pathway. In a replicated field trial, we evaluated the effects of two contrasting biochars derived from poultry litter and from hardwood on soil N2O emissions, soil ammonium (NH4+) and nitrate (NO3−) status, pasture productivity and herbage nutrient content. A liming treatment to mimic the liming equivalence of the poultry litter biochar was used to separate any effects observed from changes in soil pH. To further separate the effects of biochars on soil N status, N2O emissions and pasture N uptake, high and low N fertiliser doses (annual application of 672 kg N ha−1, 336 kg N ha−1) were superimposed across all of the treatments. The N fertiliser dose had no significant impact on pasture yield. Application of poultry litter biochar resulted in significant increases in pasture productivity under both high and low N inputs. This was achieved by alleviating soil P, and possibly K nutritional constraints that are typical in Australian Ferralsols. Under the high N fertiliser dose, emissions of N2O from the treatments and control were not significantly different (p > 0.05) and ranged between 1.14 and 1.78 kg N2O-N ha−1 across the 11-month study. The low N dose resulted in significantly lower emissions of N2O of between 0.80 and 0.84 kg N2O-N ha−1, but biochar had no significant effect on net emissions across the season. The lack of impact of biochar on N2O emissions was attributed to the relatively dry conditions over the trial period resulting in nitrification being the most likely N-transformation pathway. During brief episodes of high soil moisture, peak emissions from the biochar plots were lower than from the control or lime treatment, but these differences did not impact on the emission budget over the 11-month sampling campaign.No Full Tex

Planning for Human Implantat ion of a Cor t ical Visual Prothesis (Semester Unknown) IPRO 306: Planning for Human Implantation of a Cortical Visual Prothesis IPRO 306 MidTerm Presentation F08

Over the years there has been intensive research on visual prosthesis around the world and significant technological advancements have been made. The Intracortical Visual Prosthesis Team (IVP) at IIT has been researching and developing a procedure as well as a device which will be implanted within the human visual cortex. The device consists of sub-miniature electrodes which will artificially stimulate the visual cortex by introducing electrical currents in to the cortex. The IIT Team has reached a point in their 10 year development process where they would like to proceed with implanting the device in a volunteer in the next few years. Implantation of a device which provides artificial vision is an extraordinarily complex process. In the initial stages the medical and engineering aspects are the most prevalent ones, but as the project moves forward there are some questions that inevitably must be answered or at least considered. These questions deal much less with the technology and much more with the volunteers that will eventually have these complex devices implanted. To try and answer some of these questions, in IPRO 306 we will look into various medical, political, engineering, ethical, media and psychological issues that we believe may become of greater importance as the project progresses into the implementation stage. We will also look into the public relations aspect as well as some political and psychological issues. Based on our research and understanding we will provide several issues that we see as needing to be addressed in the future and recommend possible solutions to them.Deliverable