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关键词： HIV   Molecular surveillance   Molecular epidemiology   Molecular transmission network   Community detection   Exponential random graph model  

摘要： Large clusters in HIV-1 molecular networks contain a substantial proportion of people living with HIV and dominate local epidemics; however, their large size and complex structure pose a challenge for effective public health interventions. We developed an analytical framework to partition the large cluster into small groups for precise intervention. In the HIV-1 CRF07_BC molecular transmission network in Guangzhou, China (2008-2020), a giant component (681 members) was partitioned into 34 communities with dense internal and sparse external links. All 378 inter-community links involved high-centrality members from Community 1 (P < 0.001) and phylogenetic analysis identified Community 1 as the most likely ancestral source of the giant component (marginal probability = 0.989). Exponential random graph models (ERGMs) revealed significant homophily effect among members with specific characteristics in the giant component and its large communities, highlighting potential outbreaks within specific subgroups. Partitioning giant components into communities may be a promising approach to help develop community-level interventions and could improve the effectiveness of interventions targeted at large clusters.

关键词： Poincar & eacute   Steklov operator   d-sets   Laplacian transport   fractal  

摘要： We correct different points of article K. Arfi, A. Rozanova-Pierrat, Dirichlet-to-Neumann or Poincar & eacute;-Steklov operator on fractals described by d-sets. Discrete & Continuous Dynamical Systems-S, Vol. 12, No. 1, 2019, pp. 1-26.

关键词： Magnetic fuel treatment   Jet A-1   Swirl combustor   OH* chemiluminescence   LIIsoot diagnostics   Emissions  

摘要： Magnetic fuel treatment has been proposed as a low-cost and additive-free technique for improving combustion and reducing emissions. However, its effects on aviation fuels, particularly Jet A-1 under swirl-stabilized combustion conditions, remain insufficiently understood. This study experimentally investigates the influence of magnetic fuel treatment on the combustion and emission characteristics of Jet A-1 in an atmospheric swirl combustor. Jet A-1 was treated using a 7,000 Gauss magnetic field, and its fuel-property changes were evaluated through viscosity measurements and FTIR absorption analysis using n-hexane as a simple alkane model compound. Combustion experiments were conducted using a non-swirling bluff-body configuration (S = 0) and an axial swirler (S = 0.82) over different equivalence ratios. OH* chemiluminescence imaging, laser-induced incandescence (LII), and FTIR exhaust-gas analysis were employed to characterize the reaction zone, soot distribution, and gaseous emissions. The results showed that magnetic treatment temporarily reduced the dynamic viscosity of Jet A-1 by approximately 2.7%, while the FTIR spectra of n-hexane indicated changes in the absorption intensities of CH₂ and CH₃ vibration modes after magnetic exposure. These results suggest possible short-term changes in bulk fuel properties and molecular-level behavior, although they should be regarded as qualitative indications rather than direct evidence of Jet A-1 combustion mechanisms. For the combustion results, the magnetically treated Jet A-1 generally exhibited stronger OH* chemiluminescence, shorter lift-off lengths, and lower LII soot intensities than the untreated fuel. In the emission analysis, CO emissions were reduced by up to 34.5% for the S0 configuration and 11.1% for the S45 configuration at ER = 1.4 after magnetic treatment. The HC emission of S0_UM was approximately 13% lower than that of S0_NM on average, and the N₂O emission decreased by

关键词： Methane oxidation   Sulfur poison   Catalyst regeneration   Activity promotion   Mechanism study  

摘要： Pd-based catalysts with high C–H activation ability have been extensively studied in catalytic methane oxidation, but suffer from sulfur-induced deactivation. The recently reported SO₂-induced activity promotion phenomenon brings a glimmer of hope for solving this problem, but the relevant mechanism is still unclear. Herein, the Pd/Ce_xZr_1-xO₂ is designed and reveals a SO₂-induced CH₄ oxidation enhancement. A two-step mechanism is proposed to illustrate the role of SO₂: (i) the adsorption of SO₂ on the PdO_x and then migrates to bulk support to generate bulk sulfates; (ii) the reservation of SO₂ by bulk support reaches saturation and the accumulation of surface sulfates occurs. During the first step, SO₂ increases adosrbed oxygen species and modifies the interaction between Pd and CZ support. By combining these two functions of SO₂, methane activation on Pd/CZ catalysts is facilitated. The second step elucidates the mechanism of SO₂-induced deactivation. Besides, the oxidizing atmosphere is favorable for catalyst regeneration, but the presence of stable support sulfates results in the limited activity recovery. This work provides a meaningful reference for the understanding of sulfur-induced deactivation process and the development of sulfur-resistant Pd based catalysts for CH₄ oxidation and other applications.

关键词： Dry reforming of methane   Chemical looping   Fluidized bed   Oxygen carriers   A -site cation-deficient  

摘要： Chemical looping dry reforming of methane (CL-DRM) in fluidized bed reactors represents a promising approach for the conversion of CO₂ and CH₄ into hydrogen-rich syngas. However, the development of oxygen carriers (OCs) with both high reactivity and sufficient mechanical stability under fluidized bed conditions remains a critical challenge. In this work, A-site cation-deficient ${\text{La}}_{\text{1-x}}{\text{FeO}}_{\text{3-}\mathrm{\delta }}$ OCs were synthesized and evaluated for CL-DRM applications in a fluidized bed reactor. The effects of A-site cation-deficient level (x in ${\text{La}}_{\text{1-x}}{\text{FeO}}_{\text{3}\text{-}\mathrm{\delta }}$), particle size, and fluidization velocity on CH₄ conversion were investigated. Among the tested materials, ${\text{La}}_{\text{0.95}}{\text{FeO}}_{\text{3-}\mathrm{\delta }}$ exhibited the highest catalytic activity, achieving a CH₄ conversion of 75 %, a CO selectivity of 97.5 %, and a syngas yield (H₂ + CO) of 9 mmol/g, while maintaining stable performance over 10 redox cycles at 850 °C. Fine particles (100–200 μm) show higher CH₄ conversion compared to larger particle sizes (200–300 μm), mainly due to improved gas–solid contact associated with the combined effects of minimum fluidization voidage (<

关键词： Biomass   Coal   Dual fluidized bed   Gasification   Pilot plant  

摘要： This study presents a hydrodynamic and operational assessment of a 1 MW_th pilot-scale dual fluidized bed (DFB) gasification system, which is equipped with a gasifier, a combustor, a riser, cyclones, and L–valves to regulate solid circulation under reactive gasification conditions. A 48–hour test campaign was conducted using quartz sand as bed material with bituminous coal and biomass as feedstocks. Stable operation was achieved with gasifier and combustor temperatures of ∼ 700 °C and 800–900 °C, respectively, at a system pressure of 200–300 kPaG. A solid circulation rate (G_s) of ∼ 98.3 kg/m²⋅s was maintained via L–valve regulation, corresponding to a riser pressure drop of 2.3  kPa. Coal gasification exhibited increase in H₂ concentration from 30.3 to 67.1 vol%, attributed to stable char inventory facilitating gasification reaction. In contrast, biomass gasification exhibited pronounced operational instability, with transient H₂ concentration peaks reaching only 22.4 vol% and substantial tar formation (28.2  g/Nm³), dominated by oxygen–rich secondary tars. Under biomass gasification, most char is consumed in the gasifier, leading to insufficient char recirculation for combustion, consequently reducing heat generation and causing temperature fluctuations (600–850 °C). Overall, the results demonstrate that active L-valve control enables stable solid circulation and feedstock flexibility, thereby providing a validated hydrodynamic framework for pilot-scale of DFB gasification systems.

关键词： Danshen-chuanxiong   Multi-omics   Cerebral ischemia   Carnitine metabolism   Angiogenesis  

摘要： Cerebral ischemia remains a leading cause of mortality and long-term disability. Current therapeutic interventions are still limited by a narrow therapeutic time window, hemorrhagic risk, and incomplete functional recovery against the complex pathological cascade of ischemic injury. Salvia miltiorrhiza−Ligusticum chuanxiong (Danshen-Chuanxiong, DC) herb pair, widely recognized in clinical practice, is extensively employed as a therapeutic intervention for cerebral ischemia. Nevertheless, the bioactive ingredients of DC and its underlying mechanism in cerebral ischemia remain largely unclear.

关键词： 1-D PS-MA   Virtual array   PARAFAC decomposition   DOA and polarization estimation  

摘要：

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  Implicit rotation invariance of the cosine-form manifold is derived for 1-D PS-MA.
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  Joint DOA and polarization estimation is achieved by analyzing the decomposed factor matrices.
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  The proposed method avoids spectrum search and achieves automatic DOA-polarization pairing.

关键词： Diesel engine   Boron doped filter   Exhaust emission   Catalyst   Environmental effect   Activated carbon  

摘要： One of the main causes of environmental pollution is the exhaust emissions emitted from internal combustion engines. Currently, the use of rare elements such as platinum, palladium and rhodium in metal catalysts, which form part of exhaust purification systems, causes production difficulties and increased costs. Furthermore, these elements do not possess particle retention properties. This study aimed to determine whether geopolymer materials could be used as an innovative exhaust purification system in the automotive industry, given that porous geopolymer structures contain catalyst materials, are resistant to pressure and temperature, are easy and inexpensive to apply, and can be made from waste raw materials. In this study, newly developed aluminum-carbon-boron (5% Al₂O₃ and 1% activated carbon) doped emission treatment filter (also named as “AlCBDoF”) and zirconium-boron (5% ZrO₂ and 5% Zr(SO₄)₂) doped emission treatment filter (also named as “ZrBDoF”) are developed and their effects on the diesel engine performance and emissions were investigated. The developed novel emission treatment filters and a standard catalytic converter of the diesel engine were separately installed in the exhaust after treatment line of a 4-cylinder diesel engine under different speeds and loads. When standard catalytic converter is used, HC emissions are improved by up to 48%, while HC emissions are reduced by 60% when AlCBDoF is used and 70% when ZrBDoF is utilized. The fact that the filter output values of the CO₂ are higher than the filter input values shows that the filters are effective in CO₂ conversion of CO emissions by acting as a catalyst. It has also been observed to demonstrate over 99% improvement in particulate matter. Therefore, the newly developed Boron Doped Filters can be used as a single device instead of both Diesel Oxidation Catalyst and Diesel Particulate Filter. In addition to improving

关键词： Importance sampling   Instantons for rare impactful events   N-1 contingencies   Power system dynamics under faults   Transmission grids  

摘要：

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  A probabilistic framework for real-time screening of dynamic N-1 grid contingencies is proposed.
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  Dynamic overload risk is quantified using a time-integrated overload indicator derived from swing-equation dynamics.
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  A scalable analytical solution of the linearized swing equations enables fast evaluation of post-fault trajectories.
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  Cross-entropy importance sampling efficiently estimates probabilities of rare high-impact transient overload events.
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  Case studies demonstrate probabilistic assessment of dynamic congestion and identification of vulnerable transmission assets.