Solid biomass oxy-fuel combustion with external recirculation was demonstrated in a 100-kW atmospheric, down-fired combustor operated close to stoichiometry. The external recirculation setup comprised a particulate filter, a condenser, a fan and O2 addition before the burner inlet. A theoretical description of the recirculation process is presented and validated. Two fuels, softwood (SW) and forest residues (FR), with similar residence times, were compared. Gaseous species, including potassium (K) compounds (atomic K, KOH, and KCl), and gas temperature were quantified in real-time by tunable diode laser absorption spectroscopy (TDLAS) and photofragmentation TDLAS at two locations in the reactor core. Major species (CO2, H2O, O2, and N2) were also measured at the exhaust. Flue gas particles collected with a low-pressure impactor at the exhaust were analyzed by X-ray powder diffraction and scanning electron microscopy. The average CO2 purity (dry) was 90 % for SW and 86 % for FR. The NO concentration was higher for FR due to the larger nitrogen content in the fuel. The gaseous K species concentrations were higher for FR than for SW (factor 2-3), but not as high as expected from the difference in fuel K content (factor 7), likely due to the high content of Si and Al in FR. Gas-phase K was significantly lower than predicted by thermodynamic equilibrium calculations (TEC), probably due to K adsorption by soot particles. The fine and coarse particle concentrations were significantly higher for FR than for SW due to the higher ash content of FR. The FR fine mode particles consisted mainly of K2SO4 and KCl, in good quantitative agreement with TEC of gas phase condensation. Apatite, Ca5(PO4)3OH, likely formed from vaporized Ca and P, was found in the fine mode in all recirculation cases.
Biochar performance in applications like soil amendment depends on properties including porosity, surface area, and pore structure, which are influenced by both process conditions and feedstock characteristics such as wood anatomy. However, their effects across micro-and nanometre length scales remain poorly understood. This study therefore investigates how feedstock and process conditions affect properties of pine wood biochar produced in industrially relevant pilot-scale continuous reactor for torrefaction (291-315 degrees C, 6-12 min) and pyrolysis (350-400 degrees C, 25 min). High-resolution X-ray microtomography combined with AI-assisted image analysis was used to quantify earlywood-latewood distribution, porosity, pore size, cell wall thickness, and micrometre-scale surface area, while N(2)and CO(2)sorption probed nanometre-scale structure. The wood microstructure was largely preserved across treatments, resulting in highly anisotropic pore networks. Porosity remained high (33-77%), primarily influenced by earlywood-latewood variability rather than temperature. From torrefaction to pyrolysis, cell wall thickness and pore diameter decreased, while microporosity (
Purpose Rupture of the extensor pollicis longus (EPL) tendon is an uncommon but clinically important complication of distal radius fractures. We investigated its incidence, timing, associated factors, and functional consequences in a prospective cohort. Methods This is a secondary analysis of a prospective multicenter cohort at two Swedish orthopedic departments, 2009–2012. Consecutive adults with acute distal radius fractures were enrolled and followed to 12 months. EPL function was assessed by active thumb extension testing at 3 and 12 months. Extensor tendon status was recorded in 419 fractures at 3 months and 373 at 12 months. Associations were analyzed between EPL rupture and age, sex, initial fracture displacement, dorsal comminution, treatment modality, surgical technique, 12-month grip strength, Disabilities of the Arm, Shoulder, and Hand (QuickDASH), and EQ-5D. Results Ten EPL ruptures were identified among the 419 fractures assessed at 3 months, representing an incidence of 2.4%. One rupture was acute; none occurred between 3 and 12 months. Seven ruptures occurred in undisplaced or minimally displaced fractures, and three occurred in displaced fractures (P = .06). Four followed surgical treatment, and six followed nonsurgical management. EPL rupture was not significantly associated with age, sex, dorsal comminution, treatment type, or surgical technique. At 12 months, grip strength, QuickDASH, and EQ-5D did not differ significantly between patients with and without EPL rupture. Seven of the 10 patients with rupture underwent tendon transfer; 12-month QuickDASH scores did not differ between these subgroups. Conclusions EPL rupture occurred in 2.4% of distal radius fractures, and all cases occurred within 3 months. No clear demographic, fracture-related, or treatment-related risk factors were identified. Long-term grip strength, function, and quality of life were comparable between patients with and without rupture. Outcomes were acceptable in the few selected patients managed nonsurgically, but the study was not powered to compare treatments. These findings underscore the importance of early surveillance and support an individualized approach. Type of study/level of evidence Prognostic II.
Dementia is a multifactorial clinical syndrome, for which neurotropic herpes viruses have been proposed as potential contributors to disease etiology. While varicella-zoster virus (VZV) vaccination has been associated with reduced dementia risk, little is known about how longitudinal VZV-specific antibody dynamics relate to dementia diagnosis. To investigate this, we analysed VZV-specific IgM and IgG levels in 2867 samples from 1612 older adults living in nursing homes. Capillary blood samples were collected at seven sampling periods between 2021 and 2024. Antibody levels were linked to national registry data. Linear mixed-effects models assessed (i) pre-diagnostic differences in antibody levels between individuals who subsequently developed dementia and those who did not, (ii) longitudinal trajectories relative to diagnosis, and (iii) within-individual changes among participants with samples before and after diagnosis. VZV-IgM levels were lower in participants who were later diagnosed with dementia (estimate -0.075 log10, p = 0.037), with VZV-IgG showing a similar trend. Longitudinal models demonstrated increasing VZV antibody levels in the years surrounding dementia diagnosis, with significant yearly increases in IgM (estimate 0.0069 log10, p = 0.008) and a trend for elevated IgG, whereas no corresponding temporal changes were observed for RSV antibodies. Within a subset of participants with samples on both sides of diagnosis (n = 23), VZV-IgM and VZV-IgG levels showed consistent within-individual increases, although statistical power was limited. These findings align with epidemiological evidence linking VZV vaccination to reduced dementia risk and provide new insights into immunological changes accompanying dementia progression. Further studies are warranted to clarify causal mechanisms and the role of antiviral or vaccination strategies in dementia prevention.
