A post-wildfire response in cave dripwater chemistry

Surface disturbances above a cave have the potential to impact cave dripwater discharge, isotopic composition and solute concentrations, which may subsequently be recorded in the stalagmites forming from these dripwaters. One such disturbance is wildfire; however, the effects of wildfire on cave chemistry and hydrology remains poorly understood. Using dripwater data monitored at two sites in a shallow cave, beneath a forest, in southwest Australia, we provide one of the first cave monitoring studies conducted in a post-fire regime, which seeks to identify the effects of wildfire and post-fire vegetation dynamics on dripwater δ18O composition and solute concentrations. We compare our post-wildfire δ18O data with predicted dripwater δ18O using a forward model based on measured hydro-climatic influences alone. This helps to delineate hydro-climatic and fire-related influences on δ18O. Further we also compare our data with both data from Golgotha Cave – which is in a similar environment but was not influenced by this particular fire – as well as regional groundwater chemistry, in an attempt to determine the extent to which wildfire affects dripwater chemistry. We find in our forested shallow cave that δ18O is higher after the fire relative to modelled δ18O. We attribute this to increased evaporation due to reduced albedo and canopy cover. The solute response post-fire varied between the two drip sites: at Site 1a, which had a large tree above it that was lost in the fire, we see a response reflecting both a reduction in tree water use and a removal of nutrients (Cl, Mg, Sr, and Ca) from the surface and subsurface. Solutes such as SO4 and K maintain high concentrations, due to the abundance of above-ground ash. At Site 2a, which was covered by lower–middle storey vegetation, we see a solute response reflecting evaporative concentration of all studied ions (Cl, Ca, Mg, Sr, SO4, and K) similar to the trend in δ18O for this drip site. We open a new avenue for speleothem science in fire-prone regions, focusing on the geochemical records of speleothems as potential palaeo-fire archives. © Author(s) 2016

Study of Peri-Articular Anaesthetic for Replacement of the Knee (SPAARK): study protocol for a patient-blinded, randomised controlled superiority trial of liposomal bupivacaine

Background: Optimising the management of peri-operative pain and recovery following knee replacement has been identified as a patient priority. Current pain relief strategies use opiate-based analgesia; however, up to 50% of patients experience significant side effects. Local anaesthetic incisional infiltration is one alternative. The length of the duration of action is a major limiting factor of current local anaesthetic techniques. Liposomal bupivacaine has been reported to be effective for up to 72 h. This randomised controlled trial will evaluate the clinical and cost effectiveness of liposomal bupivacaine. Methods: SPAARK is a patient-blinded, multi-centre, active comparator, superiority, two-arm, parallel-group randomised controlled trial. Five hundred patients undergoing knee replacement will be recruited and randomised to liposomal bupivacaine plus bupivacaine hydrochloride or bupivacaine hydrochloride alone. The co-primary outcomes are the Quality of Recovery 40 measured at 72 h post-surgery and also cumulative pain measured daily using a 0–10 visual analogue scale for the first 3 days following surgery. Secondary outcomes include cumulative opioid consumption, fitness for discharge, functional outcomes assessed using the Oxford Knee Score and American Knee Society Score, the EuroQol five dimensions instrument and complications. A cost utility analysis is also planned. Discussion: The clinical effectiveness and cost effectiveness of liposomal bupivacaine have yet to be evaluated in the National Health Service, making this trial appropriate and timely. Trial registration: ISRCTN registry, ISRCTN54191675. Registered on 14 November 2017

Head Circumference of Infants Born to Mothers with Different Educational Levels; The Generation R Study

Objective: Head circumference (HC) reflect growth and development of the brain in early childhood. It is unknown whether socioeconomic differences in HC are present in early childhood. Therefore, we investigated the association between socioeconomic position (SEP) and HC in early childhood, and potential underlying factors. Methods: The study focused on Dutch children born between April 2002 and January 2006 who participated in The Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Maternal educational level was used as indicator of SEP. HC measures were concentrated around 1, 3, 6 and 11 months. Associations and explanatory factors were investigated using linear regression analysis, adjusted for potential mediators. Results: The study included 3383 children. At 1, 3 and 6 months of age, children of mothers with a low education had a smaller HC than those with a high education (difference at 1 month: -0.42 SD; 95% CI: -0.54,-0.30; at 3 months: -0.27 SD; 95% CI -0.40,-0.15; and at 6 months: -0.13 SD; 95% CI -0.24,-0.02). Child's length and weight could only partially explain the smaller HC at 1 and 3 months of age. At 6 months, birth weight, gestational age and parental height explained the HC differences. At 11 months, no HC differences were found. Conclusion: Educational inequalities in HC in the first 6 months of life can be mainly explained by pregnancy-related factors, such as birth weight and gestational age. These findings further support public health policies to prevent negative birth outcomes in lower socioeconomic groups

Albumin and multiple sclerosis

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Leakage of the blood–brain barrier (BBB) is a common pathological feature in multiple sclerosis (MS). Following a breach of the BBB, albumin, the most abundant protein in plasma, gains access to CNS tissue where it is exposed to an inflammatory milieu and tissue damage, e.g., demyelination. Once in the CNS, albumin can participate in protective mechanisms. For example, due to its high concentration and molecular properties, albumin becomes a target for oxidation and nitration reactions. Furthermore, albumin binds metals and heme thereby limiting their ability to produce reactive oxygen and reactive nitrogen species. Albumin also has the potential to worsen disease. Similar to pathogenic processes that occur during epilepsy, extravasated albumin could induce the expression of proinflammatory cytokines and affect the ability of astrocytes to maintain potassium homeostasis thereby possibly making neurons more vulnerable to glutamate exicitotoxicity, which is thought to be a pathogenic mechanism in MS. The albumin quotient, albumin in cerebrospinal fluid (CSF)/albumin in serum, is used as a measure of blood-CSF barrier dysfunction in MS, but it may be inaccurate since albumin levels in the CSF can be influenced by multiple factors including: 1) albumin becomes proteolytically cleaved during disease, 2) extravasated albumin is taken up by macrophages, microglia, and astrocytes, and 3) the location of BBB damage affects the entry of extravasated albumin into ventricular CSF. A discussion of the roles that albumin performs during MS is put forth

Dating stalagmites in mediterranean climates using annual trace element cycles

Speleothems may preserve geochemical information at annual resolution, preserving information about past hydrology, environment and climate. In this study, we advance information-extraction from speleothems in two ways. First, the limitations in dating modern stalagmites are overcome by refining a dating method that uses annual trace element cycles. It is shown that high-frequency variations in elements affected by prior calcite precipitation (PCP) can be used to date speleothems and yield an age within 2-4% chronological uncertainty of the actual age of the stalagmite. This is of particular relevance to mediterranean regions that display strong seasonal controls on PCP, due to seasonal variability in water availability and cave-air pCO2. Second, using the chronology for one stalagmite sample, trace elements and growth-rate are compared with a record of climate and local environmental change i.e. land-use and fire, over the 20th century. Well-defined peaks in soil-derived trace elements and simultaneous decreases in growth-rate coincide with extreme annual rainfall totals in 1934 and 1974. One of which, 1934, was due to a recorded cyclone. We also find that bedrock-derived elements that are dominated by PCP processes, reflect a well-known period of drying in southwest Australia which began in the 1970's

Wildfire on Karst: an Overview

Wildfires dramatically change the surface environment by removing vegetation and soil microbial communities and altering soil structure and geochemistry. Karst subsurface processes such as dissolution, cave formation and speleothem deposition are sensitive to environmental change, which is precisely why speleothems have been widely used as recorders of surface and climate change at an annual to millennial temporal scale. The effect of fire on karst processes is poorly understood. We hypothesise that a wildfire induced change at the surface will impact karst dissolution and precipitation processes. Firstly, sterilisation of the soil by heating causes a reduction in soil CO2 concentration which is a key component in dissolution processes. Secondly, removal of vegetation alters surface albedo and soil water storage properties. This could change the hydrology and isotopic signature of speleothem-forming drip water. We also hypothesise that a wildfire will produce a unique biogeochemical signature due to a change in the organic and inorganic properties of soil, which can be transported into speleothem forming drip water. Fire changes the organic matter character which is an important component in the mobilisation and transport of trace metals. Combustion of vegetation results in addition of ash derived minerals to the soil. Quantifying the biogeochemical signature from a burnt landscape will enable us to determine whether this wildfire signature is preserved in speleothems. This would provide the opportunity to use speleothems as recorders of fire history for the first time. Determining the impact of fire on karst processes would inform fire management and karst conservation policies