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Objectives: Diffusion-weighted imaging (DWI) MRI is increasingly available in veterinary medicine for investigation of the brain. However, apparent diffusion coefficient (ADC) values have only been reported in a small number of cats or in research settings. The aim of this study was to investigate the ADC values of different anatomical regions of the morphologically normal brain in a feline patient population. Additionally, we aimed to assess the possible influence on the ADC values of different patient-related factors, such as sex, body weight, age, imaging of the left and right side of the cerebral hemispheres and white vs grey matter regions. Methods: This retrospective study included cats undergoing an MRI (3T) examination with DWI sequences of the head at the Vetsuisse Faculty of the University Zurich between 2015 and 2021. Only cats with morphologically normal brains were included. On the ADC maps, 10 regions of interest (ROIs) were manually drawn on the following anatomical regions: caudate nucleus; internal capsule (two locations); piriform lobe; thalamus; hippocampus; cortex cerebri (two locations); cerebellar hemisphere; and one ROI in the centre of the cerebellar vermis. Except for the ROI at the cerebellar vermis, each ROI was drawn in the left and right hemisphere. The ADC values were calculated by the software and recorded. Results: A total of 129 cats were included in this study. The ADC varied in the different ROIs, with the highest mean ADC value in the hippocampus and the lowest in the cerebellar hemisphere. ADC was significantly lower in the white cerebral matter compared with the grey matter. ADC values were not influenced by age, with the exception of the hippocampus and the cingulate gyrus. Conclusion and relevance: ADC values of different anatomical regions of the morphologically normal feline brain in a patient population of 129 cats in a clinical setting are reported for the first time. [ABSTRACT FROM AUTHOR]

Cell-free hemoglobin in the cerebrospinal fluid (CSF-Hb) may be one of the main drivers of secondary brain injury after aneurysmal subarachnoid hemorrhage (aSAH). Haptoglobin scavenging of CSF-Hb has been shown to mitigate cerebrovascular disruption. Using digital subtraction angiography (DSA) and blood oxygenation-level dependent cerebrovascular reactivity imaging (BOLD-CVR) the aim was to assess the acute toxic effect of CSF-Hb on cerebral blood flow and autoregulation, as well as to test the protective effects of haptoglobin. DSA imaging was performed in eight anesthetized and ventilated sheep (mean weight: 80.4 kg) at baseline, 15, 30, 45 and 60 minutes after infusion of hemoglobin (Hb) or co-infusion with haptoglobin (Hb:Haptoglobin) into the left lateral ventricle. Additionally, 10 ventilated sheep (mean weight: 79.8 kg) underwent BOLD-CVR imaging to assess the cerebrovascular reserve capacity. DSA imaging did not show a difference in mean transit time or cerebral blood flow. Whole-brain BOLD-CVR compared to baseline decreased more in the Hb group after 15 minutes (Hb vs Hb:Haptoglobin: -0.03 ± 0.01 vs -0.01 ± 0.02) and remained diminished compared to Hb:Haptoglobin group after 30 minutes (Hb vs Hb:Haptoglobin: -0.03 ± 0.01 vs 0.0 ± 0.01), 45 minutes (Hb vs Hb:Haptoglobin: -0.03 ± 0.01 vs 0.01 ± 0.02) and 60 minutes (Hb vs Hb:Haptoglobin: -0.03 ± 0.02 vs 0.01 ± 0.01). It is demonstrated that CSF-Hb toxicity leads to rapid cerebrovascular reactivity impairment, which is blunted by haptoglobin co-infusion. BOLD-CVR may therefore be further evaluated as a monitoring strategy for CSF-Hb toxicity after aSAH. [ABSTRACT FROM AUTHOR]

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Abstract: The presence of polycyclic aromatic hydrocarbons/compounds (PAH/PAC) in the exhaust of combustion equipment as well as their growth to soot particles depends on the balance of formation and depletion reaction pathways. Detailed understanding of PAH oxidation is necessary for a correct quantitative description of combustion processes. This study focuses on the high-temperature oxidation of anthracene, a 3-ring PAH, by molecular oxygen. By reacting this already formed PAH, under non-sooting conditions, its oxidative depletion processes were isolated from its formation processes, as well as from soot formation pathways. Anthracene powder, fluidized in nitrogen, was introduced into a two-stage electrically heated laminar-flow drop-tube furnace. In the first stage, kept at 900°C, anthracene was vaporized. Thereafter, upon mixing with preheated oxygen-containing gases in a venturi, gaseous anthracene was oxidized in the second furnace at oxygen mole fractions of 1–5% and gas temperatures of 950–1050°C. Gas temperature and velocity profiles in the furnaces, as well as anthracene particle vaporization trajectories were obtained with a computational fluid dynamics code. Sampling, followed by chemical analysis, was conducted at three locations within the oxidizing furnace. Trends with residence time show increasing CO and CO2 yields in the furnace and gradually decreasing O2. CO increased with higher oxidizing temperatures and oxygen concentrations. Acetylene was the most abundant light hydrocarbon, followed by methane, ethylene, benzene, propylene and ethyl acetylene. Prevalent PAC included fluorene-9-one, 9,10-anthracenodione, biphenylene, dibenzofuran, fluorene, indene, naphthalene, anthrone, xanthone and 2-naphthalenecarboxaldehyde. Most species’ yields increased with rising oxidation temperatures. A global anthracene reaction rate with oxygen was deduced, and an activation energy of 71kJ/mol was calculated. An anthracene oxidation reaction scheme was proposed. [Copyright &y& Elsevier]

Abstract: Samples of condensable material from opposed flow diffusion flames of methane and acetylene and oxygen enriched air at atmospheric pressure were collected and analyzed by high-pressure liquid chromatography to determine the fullerene yield. High resolution transmission electron microscopy studies revealed the presence of fullerenes and well-defined carbon layers with various degrees of curvature. Results show that fullerene formation strongly increases with the acetylene content in the fuel. Increasing strain rate positively affects the fullerene content in the condensable material; higher strain rate flames favor fullerenes over soot, indicating lower fullerene consumption by soot due to lower soot concentration. If the oxygen content in the oxidizing oxygen/nitrogen mixture is increased, fullerene concentration increases due to the higher temperatures and higher precursor concentration. Similar relative variations of fullerene concentrations with flame conditions are predicted by the numerical model. However, the absolute concentrations of fullerenes are, in general, underpredicted by 4 orders of magnitude. This result can be partially attributed to uncertainties in the rate coefficients for H-abstraction and C2H2-addition. This discrepancy also suggests that other important fullerene formation pathways are to be included in the numerical model. [Copyright &y& Elsevier]

Abstract: Combustion-generated polycyclic aromatic hydrocarbons (PAH) and soot particles are of significant environmental concern whereas controlled combustion is of increasing interest for the synthesis of carbonaceous nanostructures such as fullerenic material. Improved understanding of chemical and physical processes involved in PAH and soot formation is required to correlate operating conditions with emission characteristics. A detailed kinetic model describing the formation and consumption of PAH and soot in fuel-rich hydrocarbon combustion has been developed. Using a sectional approach, large PAH and carbonaceous particles with diameters of up to ?70nm are defined as classes (BINs) covering given mass ranges. Numbers of carbon and hydrogen atoms corresponding to their average masses are assigned to each BIN, accounting for a decrease in H/C ratios with increasing particle size. The model has been successfully tested for a rich premixed benzene/oxygen/argon flame (? =2.4, 10% argon, v =25cms?1, 5.33kPa). Model predictions are compared with published experimental data including mole fraction profiles of individual PAH and concentration as well as number density profiles of soot. Reactions of PAH radicals with PAH and between PAH radicals were found to be the dominant pathway to soot nuclei. Surface growth contributes ?75% to the final particle mass, and reaction of acetylene with particle radicals is the major growth pathway. Surface growth reactions are involved in PAH depletion in the postflame zone. Particle coagulation involving BINs and BIN radicals significantly contributes to the formation of progressively larger particles whereas oxidation by OH plays a non-negligible role in their depletion. [Copyright &y& Elsevier]

Application of lanthanum carbonate causes significant lanthanum deposition in the human body, which is similar to gadolinium deposition from gadolinium-based contrast agents. • Two similar elements applied in different species to the same patient. • LA-ICP-MS method reveals correlating iatrogenic La and Gd deposition. • La deposition from applied La carbonate is detected, but its effects are unknown. • Concentration ratio-based approach shows differences between Gd and La deposition. • Transport of lanthanides into the brain is highly species dependent. Recently, gadolinium from linear GBCAs has been reported to deposit in various regions of the body. Besides gadolinium, other lanthanides are used in medical care. In the current study, we investigated deposition of lanthanum in two patients who received lanthanum carbonate as a phosphate binder due to chronic kidney injury and compared it to additionally found Gd deposition. Tissue specimens of two patients with long-term application of lanthanum carbonate as well as possible GBCA application were investigated. Spatial distribution of gadolinium and lanthanum was determined by quantitative laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) imaging of tissue sections. The deposition of gadolinium and lanthanum in different organs was compared, and the ratio of Gd concentration to La concentration (Gd-to-La-ratio) was investigated on an individual pixel base within the images. Deposition of Gd and La was found in all investigated tissues of both patients. Gd and La exhibited high spatial correlation for all samples, with the main deposition being located in the middle coat (tunica media) of blood vessels. The Gd-to-La-ratio was similar in the tissues investigated (between 8 ± 4 (mean ± standard deviation) and 10 ± 2), except for the thyroid vasculature and surrounding tissue (90 ± 17) as well as the cerebellum (270 ± 18). Here, the ratio was significantly increased towards higher Gd concentration. The results of this study demonstrate long-term deposition of La and comparable localization of additionally found Gd in various tissues of the body. La deposition was relatively low, considering the total administered amount of lanthanum carbonate of up to 11.5 kg, indicating a low absorption and/or high excretion of lanthanum. However, the total amount of deposited La is significant and raises questions about possible adverse side effects. The ratio-approach allows for the usage of the additionally generated Gd data, without detailed knowledge about possible GBCA applications. The significantly decreased Gd-to-La-ratio in the brain might be explained by the lanthanum being released and taken up as free La3+ ion in the stomach that impedes a crossing of the blood-brain-barrier while the intravenously injected GBCAs might dechelate first when they have already crossed the blood-brain-barrier. [ABSTRACT FROM AUTHOR]