ABSTRACT
Periodontitis, an infectious inflammatory disease influenced by various factors, disrupts the delicate balance between the host microbiota and immunity. The resulting excessive immune response exacerbates the progressive destruction of the supporting periodontal tissue. Macrophages are essential elements of the host innate immune system. They are pivotal components in the periodontal immune microenvironment and actively participate in both physiological and pathological processes of periodontal tissue. When confronted with periodontitis-related irritant factors, macrophages may differentiate to pro- or anti-inflammatory subtypes that affect tissue homeostasis. Additionally, macrophages may die in response to bacterial infections, potentially affecting the severity of periodontitis. This article reviews the typical mechanisms underlying macrophage death and its effects on periodontitis. We describe five forms of macrophage death in periodontitis: apoptosis, pyroptosis, necroptosis, ferroptosis, and ETosis. Our review of macrophage death in the pathophysiology of periodontitis enhances comprehension of the pathogenesis of periodontitis that will be useful for clinical practice. Although our review elucidates the complex mechanisms by which macrophage death and inflammatory pathways perpetuate periodontitis, unresolved issues remain, necessitating further research.
ABSTRACT
An alumina porous layer open-tubular (Al2O3 PLOT) column coated with γ-alumina nanoparticles (20 nm) for highly volatile hydrocarbons (C1 to C5) separation was described. Relative to the coating of bulk alumina, this column was easily coated with dynamic method under 0.4 or 0.6 MPa for 0.53 mm or 0.32 mm capillary, respectively. And the thickness of coating layer could be tuned by repeating the coating process after column was dried and activated at 300 °C for 3 h. The effect of deactivation agents on the physicochemical properties of nano γ-alumina was characterized by X-ray diffraction (XRD) measurement and nitrogen adsorption-desorption isotherms. The influences of deactivation agents, film thickness, conditioning and column dimensions on the inertness, polarity, selectivity and elution order of C1 to C5 separation were investigated in detail. The crystallite structure and size of nano alumina were not affected by the deactivation agents and remained constant during the column making processes, whereas specific surface area, pore volume and average half pore width altered significantly. The specific surface area decreased to 125.4 m2 g-1 or 174.0 m2 g-1 and the average half pore size distributions decreased to 1.6-8.4 nm or 2.4-14.3 nm when it was deactivated with potassium chloride or sodium sulfate solution, respectively. The deactivation agents and its concentrations impacted significantly on the retention performance of column. The column deactivated with sodium sulfate solution exhibited stronger polarity and lower selectivity than which deactivated with potassium chloride solution although both columns showed good inertness. The length, internal diameter and film thickness of the column had less influence on the selectivity and resolution for C1 to C5 hydrocarbons separation, whereas the conditioning temperature and time had an obvious influence. The column had distinguished polarity and selectivity which was different from either bulk or commercial alumina columns. Typically, the hydrocarbons were baseline separated with resolutions ranging from 1.65 to 15.33 within 9 min under programmed temperature below 100 °C, and the tailing factors ranging from 1.02 to 1.07.
