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An investigation on the dispersal characteristics of the cylindrically packed material of dry powder particles driven by explosive load is presented. By establishing a controllable experimental system under laboratory conditions and combining with near-field simulation, the particle dispersal process is described. Additionally, Kelvin-Helmholtz instability is observed during the process of jet deceleration dispersal. The characteristic parameters of radially propagated particles are explored under different mass ratio of particle-to-charge (M/C). Results indicate that, when the charge mass remains constant, an increase in M/C leads to a decrease in dispersed jet number, void radius and maximum velocity, wherein the maximum velocity correlates with calculations by the porous Gurney model. The case of the smaller M/C always has a higher outer-boundary radius and area expansion factor. Findings indicate that when particles detach from the jet upon reaching minimum acceleration and entering low-speed far-field stage from high-speed near-field stage, the outer-boundary radius is 30~36 times the initial particles' body radius under different M/C. In addition, particle concentration distribution over time and distance is qualitatively analyzed by the grayscale image method. This research can be referential for improving the fire-extinguishing capacity of extinguishing bombs and the damage property of fuel air explosive (FAE).

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BACKGROUND: Some previous studies showed abnormal pathological and vascular changes in the retina of patients with Alzheimer's disease (AD). However, whether retinal microvascular density is a diagnostic indicator for AD remains unclear. OBJECTIVE: This study evaluated the macular vessel density (m-VD) in the superficial capillary plexus and fovea avascular zone (FAZ) area in AD, explored their correlations with clinical parameters, and finally confirmed an optimal machine learning model for AD diagnosis. METHODS: 77 patients with AD and 145 healthy controls (HCs) were enrolled. The m-VD and the FAZ area were measured using optical coherence tomography angiography (OCTA) in all participants. Additionally, AD underwent neuropsychological assessment, brain magnetic resonance imaging scan, cerebrospinal fluid (CSF) biomarker detection, and APOE ɛ4 genotyping. Finally, the performance of machine learning algorithms based on the OCTA measurements was evaluated by Python programming language. RESULTS: The m-VD was noticeably decreased in AD compared with HCs. Moreover, m-VD in the fovea, superior inner, inferior inner, nasal inner subfields, and the whole inner ring declined significantly in mild AD, while it was more serious in moderate/severe AD. However, no significant difference in the FAZ was noted between AD and HCs. Furthermore, we found that m-VD exhibited a significant correlation with cognitive function, medial temporal atrophy and Fazekas scores, and APOE ɛ4 genotypes. No significant correlations were observed between m-VD and CSF biomarkers. Furthermore, results revealed the Adaptive boosting algorithm exhibited the best diagnostic performance for AD. CONCLUSION: Macular vascular density could serve as a diagnostic biomarker for AD.

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AIMS: We mainly evaluate retinal alterations in Alzheimer's disease (AD) patients, investigate the associations between retinal changes with AD biomarkers, and explore an optimal machine learning (ML) model for AD diagnosis based on retinal thickness. METHODS: A total of 159 AD patients and 299 healthy controls were enrolled. The retinal parameters of each participant were measured using optical coherence tomography (OCT). Additionally, cognitive impairment severity, brain atrophy, and cerebrospinal fluid (CSF) biomarkers were measured in AD patients. RESULTS: AD patients demonstrated a significant decrease in the average, superior, and inferior quadrant peripapillary retinal nerve fiber layer, macular retinal nerve fiber layer, ganglion cell layer (GCL), inner plexiform layer (IPL) thicknesses, as well as total macular volume (TMV) (all p < 0.05). Moreover, TMV was positively associated with Mini-Mental State Examination and Montreal Cognitive Assessment scores, IPL thickness was correlated negatively with the medial temporal lobe atrophy score, and the GCL thickness was positively correlated with CSF Aß42 /Aß40 and negatively associated with p-tau level. Based on the significantly decreased OCT variables between both groups, the XGBoost algorithm exhibited the best diagnostic performance for AD, whose four references, including accuracy, area under the curve, f1 score, and recall, ranged from 0.69 to 0.74. Moreover, the macular retinal thickness exhibited an absolute superiority for AD diagnosis compared with other enrolled variables in all ML models. CONCLUSION: We identified the retinal alterations in AD patients and found that macular thickness and volume were associated with AD severity and biomarkers. Furthermore, we confirmed that OCT combined with ML could serve as a potential diagnostic tool for AD.

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Oxygen plays a crucial role in coal spontaneous combustion (CSC), and the magnitude of oxygen concentration determines the oxidation reaction intensity of CSC. This work is aiming to investigate the contribution of oxygen concentration to CSC and to predict the spontaneous combustion stage of coal at different oxygen concentrations. Firstly, experiments on the spontaneous combustion of coal samples at six oxygen concentrations (6%, 9%, 12%, 15%, 18%, and 21%) were carried out combined with a temperature-programmed system. Then, the gas products at different temperature stages were extracted to provide detailed classification and assessment of the indicator gasses for coal spontaneous combustion at different oxygen concentrations. The results show that the oxygen concentration and the crossing point temperature (CPT) are inversely proportional. The higher the oxygen concentration, the more intense the coal-oxygen complex reaction and the greater the gas product concentration. The critical temperature of some stages in high oxygen concentration environment is lower than that in low oxygen concentration environment. The oxidation process can be slowed down by reducing the oxygen concentration as much as possible. Indicator gasses are different for different oxygen concentration environments and should be selected reasonably and optimally to match the specific environment for judging natural coal fires in order to effectively prevent coal spontaneous combustion fire disasters.

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Whether structural alterations of intraretinal layers are indicators for the early diagnosis of Parkinson's disease (PD) remains unclear. We assessed the retinal layer thickness in different stages of PD and explored whether it can be an early diagnostic indicator for PD. In total, 397 [131, 146, and 120 with Hoehn-Yahr I (H-Y I), H-Y II, and H-Y III stages, respectively] patients with PD and 427 healthy controls (HCs) were enrolled. The peripapillary retinal nerve fiber layer (pRNFL), total macular retinal thickness (MRT), and macular volume (TMV) were measured by high-definition optical coherence tomography, and the macular intraretinal thickness was analyzed by the Iowa Reference Algorithms. As a result, the PD group had a significantly lower average, temporal quadrant pRNFL, MRT, and TMV than the HCs group (all p < 0.001). Moreover, the ganglion cell layer (GCL), inner plexiform layer (IPL), and outer nuclear layer were thinner in patients with PD with H-Y I, and significantly decreased as the H-Y stage increased. In addition, we observed that GCL and IPL thicknesses were both correlated with Movement Disorder Society-Unified Parkinson's Disease Rating Scale III (MDS-UPDRS III) scores and non-motor symptoms assessment scores. Furthermore, macular IPL thickness in the superior inner (SI) quadrant (IPL-SI) had the best diagnostic performance in patients with PD with H-Y I versus HCs, with a sensitivity and specificity of 75.06% and 81.67%, respectively. In conclusion, we confirmed the retinal structure was significantly altered in patients with PD in different clinical stages, and that GCL and IPL changes occurred during early PD disease and were correlated with MDS-UPDRS III scores and non-motor symptoms assessment scores. Furthermore, macular IPL-SI thickness might be performed as an early diagnostic indicator for PD.

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As a key parameter, the particle size of residual coal contributes greatly to its oxidation characteristics, so it is a significant and far-reaching topic to explore the role of different particle sizes in coal spontaneous combustion disaster. In this work, temperature-programmed system (TPS) was applied to analyze the oxygen consumption rate and CO and C2H4 production rules of six groups of coal samples with different particle sizes in the process of oxidation heating. The critical temperature (CT) and xerochasy temperature (XT) of different coal samples were obtained, and the coal oxidation process was divided into three stages (S1, slow oxidation stage; S2, fast oxidation stage; and S3, combustion stage). Then, the apparent activation energy (E) and pre-exponential factor (A) in three stages were regressed combined with Arrhenius formula. The results show that the smaller the coal particle size is, the larger the specific surface area is, the stronger the adsorption capacity of coal molecules and oxygen molecules is, resulting in the larger oxygen consumption rate. The values of CT and XT with particle size of 0.125-0.18 mm and 2-4 mm are the smallest and largest. For coal samples with the same particle size, the maximum values of E and A occur in stage S3 and the minimum values appear in stage S1. This is mainly due to the higher temperature of stage S3, which allows the activation of functional groups with higher apparent activation energy, stronger collisions between activated molecules, and more intense oxidation reactions.

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A new method for the synthesis of di- and trisubstituted pyrroles via copper-catalyzed cyclization of ethyl allenoates with activated isocyanides has been developed. In contrast to related annulation reactions previously reported, this new process features a skeletal rearrangement in which the aryl sulfonyl moiety, which functions as the electron-withdrawing group in the α-carbon of the isocyanide, was found to migrate to the γ-carbon of the starting allenoate in the final product for the first time.