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Key PointsQuestionHow do levels of neurofilament light in cerebrospinal fluid (cNfL) compare between neurological conditions and with healthy controls? FindingsAmong 10 059 individuals in this systematic review and meta-analysis, cNfL was elevated in most neurological conditions compared with healthy controls, and the magnitude of the increase varies extensively. Although cNfL overlaps between most clinically similar conditions, its distribution did not overlap in frontotemporal dementia and other dementias or in Parkinson disease and atypical parkinsonian syndromes. MeaningThe cNfL is a marker of neuronal damage and may be useful to differentiate some clinically similar conditions, such as frontotemporal dementia from Alzheimer disease and Parkinson disease from atypical parkinsonian syndromes. This systematic review and meta-analysis assesses the associations of age, sex, and diagnosis with neurofilament light in cerebrospinal fluid and evaluates its potential in discriminating clinically similar conditions. ImportanceNeurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date. ObjectivesTo assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions. Data SourcesPubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC. Study SelectionStudies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex. Data Extraction and SynthesisIndividual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept. Main Outcome and MeasureThe cNfL levels adjusted for age and sex across diagnoses. ResultsData were collected for 10059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n=2795), dementias and predementia stages (n=4284), parkinsonian disorders (n=984), and HC (n=1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes. Conclusions and RelevanceThese data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.

Objectives To evaluate the concordance between Google Maps® application (GM®) and clinical practice measurements of ambulatory function (e.g., Ambulation Score (AS) and respective Expanded Disability Status Scale (EDSS)) in people with multiple sclerosis (pwMS). Materials and methods This is a cross-sectional multicenter study. AS and EDSS were calculated using GM® and routine clinical methods; the correspondence between the two methods was assessed. A multinomial logistic model is investigated which demographic (age, sex) and clinical features (e.g., disease subtype, fatigue, depression) might have influenced discrepancies between the two methods. Results Two hundred forty-three pwMS were included; discrepancies in AS and in EDDS assessments between GM® and routine clinical methods were found in 81/243 (33.3%) and 74/243 (30.4%) pwMS, respectively. Progressive phenotype (odds ratio [OR] = 2.8; 95% confidence interval [CI] 1.1–7.11, p = 0.03), worse fatigue (OR = 1.03; 95% CI 1.01–1.06, p = 0.01), and more severe depression (OR = 1.1; 95% CI 1.04–1.17, p = 0.002) were associated with discrepancies between GM® and routine clinical scoring. Conclusion GM® could easily be used in a real-life clinical setting to calculate the AS and the related EDSS scores. GM® should be considered for validation in further clinical studies. Supplementary Information The online version contains supplementary material available at 10.1007/s10072-021-05389-7.

The study presented hereby investigates experimentally and with CFD simulations the gas distribution effect on the hydrodynamic of a Geldart Group A turbulent fluidized bed. Experiments were carried out on a cold flow fluidized bed column with an even and uneven gas distribution. Local solid volume fraction profiles were measured using optical probes at different bed heights and along two radial directions. Optical probe measurements allow catching a clear hydrodynamic difference between both even and uneven gas distributions. These results were then used to assess CFD simulations with the code Barracuda™ (MP-PIC approach). It is noteworthy that the choice of drag correlation and boundary conditions strongly influences the agreement between the experimental and CFD results. Once the correct parameters are chosen, CFD simulations captured the effect of gas distribution changes.

The performance of a perovskite-based oxygen carrier for the partial oxidation of methane in thermochemical energy storage applications has been investigated. A synthetic perovskite with formula La0.6Sr0.4FeO3 has been scrutinized for Chemical Looping Reforming (CLR) of CH4 under fixed-bed and fluidized-bed conditions. Temperature-programmed reduction and oxidation steps were carried out under fixed-bed conditions, together with isothermal reduction/oxidation cycles, to evaluate long-term perovskite performance. Under fluidized-bed conditions, isothermal reduction/oxidation cycles were carried out as well. Results obtained under fixed-bed and fluidized-bed conditions were compared in terms of oxygen carrier reactivity and stability. The oxygen carrier showed good reactivity and stability in the range 800–1000 °C. An overall yield of 0.6 Nm3 of syngas per kg of perovskite can be reached per cycle. The decomposition of CH4 catalyzed by the reduced oxide can also occur during the reduction step. However, deposited carbon is easily re-gasified through the Boudouard reaction, without affecting the reactivity of the material. Fluidized-bed tests showed higher conversion rates compared to fixed-bed conditions and allowed better control of CH4 decomposition, with a H2:CO ratio of around 2 and CO selectivity of around 0.8. However, particle attrition was observed and might be responsible for a loss of the inventory of up to 9%w.

The tendency of ash particles to stick under high temperatures is dictated by the ash chemistry, particle physical properties, deposit surface properties and furnace operation conditions. A model has been developed in order to predict the particle sticking efficiency for fly ash deposition at high temperatures. The model incorporates the particle properties relevant to the ash chemistry, particle kinetic energy and furnace operation conditions and takes into consideration the partial sticking behaviour and the deposit layer. To test the model, the sticking behaviours of synthetic ash in a drop tube furnace are evaluated and the slagging formation from coal combustion in a down-fired furnace is modelled. Compared with the measurements, the proposed model presents reasonable prediction performance on the particle sticking behaviour and the ash deposition formation. Through a sensitivity analysis, furnace operation conditions (velocity and temperature), contact angle and particle size have been found to be the significant factors in controlling the sticking behaviours for the synthetic ash particles. The ash chemistry and furnace temperature dictate the wetting potential of the ash particles and the melting ability of the deposit surface; particle size and density not only control the particle kinetic energy, but also affect the particle temperature. The furnace velocity condition has been identified as being able to influence the selective deposition behaviour, where the maximum deposition efficiency moves to smaller particles when increasing the gas velocity. In addition, the thermophoresis effect on the arrival rate of the particles reduces with increasing the gas velocity. Further, increasing the melting degree of the deposit layer could greatly enhance the predicted deposition formation, in particular for the high furnace velocity condition.

Thermochemical energy storage is gaining widespread consideration to increase energy dispatchability in concentrating solar thermal power plants. Accordingly, excess solar energy input drives an endothermic reaction, accomplishing high energy densities and virtually unlimited storage times. As gas–solid reactions are usually involved, multiphase reactor design is essential for the success of this technology. A novel concept of directly-irradiated fluidized bed autothermal reactor is investigated for applications in concentrated solar thermal technologies. The device can be operated as a rechargeable battery, alternating a charge phase, during which solar energy is collected and stored by an endothermal gas–solid reaction, and a discharge phase, during which the stored chemical energy is released by the reverse exothermic reaction. The autothermal operation, during the charge process, consists in the recovery of the sensible heat of the reaction products to preheat the reactants by means of an internal double-pipe countercurrent heat exchanger. This operation allows to increase the overall efficiency, reducing the required solar energy input. A compartmental model to simulate the operation of the thermochemical battery is developed and closed with constitutive equations and parameters obtained by previous experimental studies on lab-scale test facilities. Limestone calcination/carbonation has been considered as model reversible reaction. Both the charge and the discharge steps were assessed investigating the effect of the design and operational variables. For the charge operation, an optimal temperature was found around 900 °C with thermal efficiencies close to 90%. For the discharge operation, thermal efficiency was found to depend almost solely on the reactor temperature, reaching values as high as 80%, whereas the gas flowrate can be set independently. The upper limit for reaction temperature is set to the reaction equilibrium condition corresponding to the inlet concentration of carbon dioxide. The obtained results represent the basis for the realization of a new prototype, that will serve for the complete proof-of-concept of the directly-irradiated fluidized bed autothermal reactor.

This paper reports on preliminary results of an experimental investigation aimed at the development of a phenomenological model of the fate of coal/ash particles in entrained-flow slagging coal gasifiers. The study specifically addresses the interaction between the lean-dispersed particle phase and the reactor walls, and the establishment of a particle segregated phase in the near-wall region of the gasifier. Better mechanistic understanding of particle–wall interaction patterns in entrained-flow gasifiers is pursued using the tool of physical modeling. To this end a lab-scale cold flow reactor (0.04 m-ID) has been designed and set up, where molten wax is air-atomized (droplets of 50–100 μm size) into a mainstream of air to simulate the near-wall fate of char/ash particles in a real hot environment. Preliminary characterization of the hydrodynamics of the lean-dispersed phase, of its interaction with the wall, of the build-up of the liquid wall layer has been accomplished with a focus on the “sticky wall–sticky particle” subregime. The particle deposition rate at the wall and the partitioning of wax droplets between the lean-dispersed phase and the wall liquid layer have been assessed under a range of operating conditions. Temperatures of the atomized wax, of the mainstream air and of the reactor wall have been set in a range of values (120–155 °C) at which the wax was fluid. Experiments with wax feeding rate of 0.2 g s−1 and flow rate of atomizing air in the order of 0.30 m3 h−1 demonstrated that the fractional mass of wax in the dispersed phase decreased from 91% to 12% as the reactor length increased from 0.03 m to 0.27 m. The velocity of the descending wall liquid layer, whose thickness was in the order of 0.2 mm, ranged between 3 mm s−1 and 6 mm s−1. The effects of the flow rate of atomization air and of the nozzle temperature were limited.

Polymorphisms in the 3' untranslated region (3'UTR) of HLA-G, an important player in immunological tolerance, could be involved in post-transcriptional expression control, and their association with different clinical immune-related conditions including autoimmunity and transplantation is of mounting interest. Most studies have focused on a 14 base pair (bp) insertion/deletion (ins/del), while additional single-nucleotide polymorphisms (SNPs) in the HLA-G 3'UTR have been described but not extensively investigated for their clinical relevance. Here we have comparatively studied the association between 3'UTR haplotypes of HLA-G, or the 14 bp ins/del, with clinical outcome of HLA-identical sibling hematopoietic stem cell transplantation (HSCT) in 147 Middle Eastern beta-thalassemia patients. Sequence based typing of 3'UTR HLA-G polymorphisms in the patients and in 102 healthy Italian blood donors showed strong linkage disequilibrium between the 14 bp ins/del and five 3'UTR SNPs, which together could be arranged into eight distinct haplotypes based on expectation-maximization studies, with four predominant haplotypes (UTRs1-4). After HSCT, we found a moderate though not significant association between the presence of UTR-2 in double dose and protection from acute graft versus host disease (hazard ratio (HR) 0.45, 95% confidence intervals (CI): 0.14-1.45; P = 0.18), an effect that was also seen when the corresponding 14 bp ins/ins genotype was considered alone (HR 0.42, 95% CI: 0.16-1.06; P = 0.07). No association was found with rejection or survival. Taken together, our data show that there is no apparent added value of considering entire 3'UTR HLA-G haplotypes for risk prediction after allogeneic HSCT for beta-thalassemia.

Background. Persistent mixed chimerism represents a state wherein recipient and donor cells stably co-exist after haematopoietic stem cell transplantation. However, since in mostly of the studies reported in literature the engraftment state was observed in the nucleated cells, in this paper we determined the donor origin in the mature erythrocytes of patients with persistent mixed chimerism after transplantation for haemoglobinopathies. Results were compared with the engraftment state observed in singularly picked-up burst-forming unit-erythroid colonies and in the nucleated cells collected from the peripheral blood and from the marrow. Design and Methods. The donor origin of the erythrocytes was determined analyzing differences on the surface antigens of the erythrocytes suspension after incubation with anti-ABO and/or anti-C, -c, -D, -E and -e monoclonal antibodies by a flow cytometer. Short tandem repeats analysis was used to determine the donor origin of nucleated cells and burst-forming unit-erythroid colonies singularly picked up after 14 days incubation. Results. A proportion of donor-derived nucleated cells of 71%, 46%, 15% and 25% was observed at day 1364, 1385, 1314 and 932 respectively, in four transplanted patients affected by haemoglobinopathies. Similar results were also obtained in the erythroid precursors, analyzing the donor/recipient origin of the burst-forming unit-erythroid colonies, while on the contrary, at the same days of observation, a proportion of 100%, 100%, 73% and 90% donor-derived erythrocytes was observed in the four patients with persistent mixed chimerism. Conclusions. Our results showed that mostly of the erythrocytes present in four long-term transplanted patients affected by haemoglobinopathies and characterized by the presence of few donor engrafted nucleated cells were of donor origin. The indication that small proportions of donor engrafted cells might be sufficient to clinical control the disease in patients affected by haemoglobinopathies is relevant, although the biological mechanisms underlying these observations need to be further investigated.