Explore the vast range of titles available.

Although hundreds of different adjuvants have been tried, aluminum-containing adjuvants are by far the most widely used currently. It is worth mentioning that although aluminum-containing adjuvants have been commonly applied in vaccine production, their acting mechanism remains not completely clear. Thus far, researchers have proposed the following mechanisms: (1) depot effect, (2) phagocytosis, (3) activation of pro-inflammatory signaling pathway NLRP3, (4) host cell DNA release, and other mechanisms of action. Having an overview on recent studies to increase our comprehension on the mechanisms by which aluminum-containing adjuvants adsorb antigens and the effects of adsorption on antigen stability and immune response has become a mainstream research trend. Aluminum-containing adjuvants can enhance immune response through a variety of molecular pathways, but there are still significant challenges in designing effective immune-stimulating vaccine delivery systems with aluminum-containing adjuvants. At present, studies on the acting mechanism of aluminum-containing adjuvants mainly focus on aluminum hydroxide adjuvants. This review will take aluminum phosphate as a representative to discuss the immune stimulation mechanism of aluminum phosphate adjuvants and the differences between aluminum phosphate adjuvants and aluminum hydroxide adjuvants, as well as the research progress on the improvement of aluminum phosphate adjuvants (including the improvement of the adjuvant formula, nano-aluminum phosphate adjuvants and a first-grade composite adjuvant containing aluminum phosphate). Based on such related knowledge, determining optimal formulation to develop effective and safe aluminium-containing adjuvants for different vaccines will become more substantiated.

•The consistency approach is an avenue for vaccine batch release without animal testing.•In vitro testing of adjuvant biological activity contributes to animal-free potency testing of vaccines.•The aluminium-based vaccines and adjuvants tested showed in vitro NLRP3 inflammasome activation.•Benchmark dose modelling showed the activation to be due to the adjuvant only.•In vitro inflammasome activation may be used to measure adjuvant biological activity. Safety and potency assessment for batch release testing of established vaccines still relies partly on animal tests. An important avenue to move to batch release without animal testing is the consistency approach. This approach is based on thorough characterization of the vaccine to identify critical quality attributes that inform the use of a comprehensive set of non-animal tests to release the vaccine, together with the principle that the quality of subsequent batches follows from their consistent production. Many vaccine antigens are by themselves not able to induce a protective immune response. The antigens are therefore administered together with adjuvant, most often by adsorption to aluminium salts. Adjuvant function is an important component of vaccine potency, and an important quality attribute of the final product. Aluminium adjuvants are capable of inducing NLRP3 inflammasome activation. The aim of this study was to develop and evaluate an in vitro assay for NLRP3 inflammasome activation by aluminium-adjuvanted vaccines. We evaluated the effects of Diphtheria-Tetanus-acellular Pertussis combination vaccines from two manufacturers and their respective adjuvants, aluminium phosphate (AP) and aluminium hydroxide (AH), in an in vitro assay for NLRP3 inflammasome activation. All vaccines and adjuvants tested showed a dose-dependent increase in IL-1β production and a concomitant decrease in cell viability, suggesting NLRP3 inflammasome activation. The results were analysed by benchmark dose modelling, showing a similar 50% effective dose (ED50) for the two vaccine batches and corresponding adjuvant of manufacturer A (AP), and a similar ED50 for the two vaccine batches and corresponding adjuvant of manufacturer B (AH). This suggests that NLRP3 inflammasome activation is determined by the adjuvant only. Repeated freeze-thaw cycles reduced the adjuvant biological activity of AH, but not AP. Inflammasome activation may be used to measure adjuvant biological activity as an important quality attribute for control or characterization of the adjuvant.

Solketal is an important chemical product with widespread applications, and the raw materials glycerol and acetone are inexpensive, making it highly economically viable. The glycerol-acetone condensation reaction is a typical acid-catalyzed reaction. Traditional homogeneous acidic catalysts cause significant environmental pollution and are difficult to recover. Herein, PEG-800 was used as an additive, and a one-pot process was employed to prepare a series of aluminum phosphate catalysts (xP-Al-O) with different P/Al molar ratios. The physical and chemical properties of the prepared xP-Al-O catalysts were thoroughly investigated using XRD, FTIR, SEM, Py-FTIR, BET, and NH3 (CO2)-TPD methods. The results indicated that different P/Al molar ratios indeed affect the catalyst structure, and all prepared xP-Al-O samples exist in the form of amorphous aluminum phosphate, with weak acidic sites dominating the surface. The prepared catalysts were investigated for their catalytic behavior in the acetalization reaction of glycerol and acetone. The 1.1P-Al-O catalyst exhibited the highest acetone glycerol acetal yield and demonstrated good catalytic stability.

Aluminum adjuvants have been used for almost a century due to their good record of safety and efficacy. However, their preparation is rather traditional and usually exhibits batch-to-batch variations. To achieve optimal adjuvanticity, the controllable and consistent preparation of aluminum adjuvants is desired, but remains a great challenge to date. Here, the preparation of aluminum phosphate (AP) adjuvant through a microfluidic approach is investigated. A chaotic micromixer is applied to enhance the mixing between the reactants. In addition, the effects of magnetic stirring and continuous-flow shearing during the settling of the AP precipitate are compared. The influences of the concentration of reactants, flow rate, residence time, as well as the heating temperature and shear intensity in the stabilizing stage are analyzed. Results show that the current method provides better control over the particle size distribution. The median particle size Dv(50) is tunable in the range of 1.6–3.4 µm, and the uniformity index varies from 0.24 to 0.45. The isoelectric point (IEP) and the adsorption capacity are also examined. Relevant findings provide useful references for the development and optimization of AP-adjuvanted vaccines.

High flame retardancy, satisfactory mechanical properties are crucial for polymeric composites employed in fields with safety requirements. Inorganic fillers can effectively regulate the structure and composition of polymeric materials and have become an effective strategy for fabricating high-performance polymeric composites. Herein, aluminum phosphate–coated sepiolite (Sep@AlPO 4 ) fillers are fabricated as a multifunctional additive to modify polyethylene oxide (PEO), PEO nanocomposites were prepared via incorporation of Sep@AlPO 4 and phenethyl-bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (DiDOPO) in the PEO matrix, and the synergistic effects between Sep and AlPO 4 are discussed. The results reveal that Sep@AlPO 4 could simultaneously enhance the flame retardancy and strengthen the mechanical properties of PEO/DiDOPO. Additionally, Sep@AlPO 4 could increase the viscosity, storage modulus, and loss modulus of the composites. This study provides an effective strategy for fabricating enhanced flame retardants to improve the performance of polymers.

The potential of a new wet chemical process for phosphorus and aluminium recovery from sewage sludge ash by sequential elution with acidic and alkaline solutions has been investigated: SESAL-Phos (sequential elution of sewage sludge ash for aluminium and phosphorus recovery). Its most innovative aspect is an acidic pre-treatment step in which calcium is leached from the sewage sludge ash. Thus the percentage of alkaline soluble aluminium phosphates is increased from 20 to 67%. This aluminium phosphate is then dissolved in alkali. Subsequently, the dissolved phosphorus is precipitated as calcium phosphate with low heavy metal content and recovered from the alkaline solution. Dissolved aluminium is recovered and may be reused as a precipitant in wastewater treatment plants.

— We have studied the process and products of thermal dehydration of highly dispersed monoclinic AlРO 4 ⋅2Н 2 О prepared by crystallization from an aluminum phosphate solution at 95–97°C and demonstrated the influence of isothermal or polythermal heat treatment on the formation of AlPO 4 polymorphs similar in structure to α-quartz or tridymite. The formation of these phases has been shown to be related to changes in the oxygen coordination of aluminum as a result of the detachment of highly polarized molecules of water of crystallization in the composition of AlРO 4 ⋅2Н 2 О. We have assessed the electrorheological (ER) activity of AlPO 4 as a disperse phase of electrorheological fluids, with a weight fraction from 10 to 20%, and found out how AlPO 4 preparation conditions influence the shear stress of the electrorheological fluids in electric fields from 3.5 to 4.0 kV/mm. Suspensions containing tridymite AlPO 4 particles prepared under isothermal conditions have been shown to exhibit a stronger ER effect, at a level from 420 to 620 Pa. The ER activity of AlPO 4 has been shown to increase with increasing heat treatment temperature and time, which is attributable to the formation of a more defect-rich particle surface due to intrinsic thermal disorder.

This study considers the features of the chemical composition, internal structure, and oscillatory zoning of sulfosalts and sulfates in the epithermal high–intermediate-sulfidation-type Au-Ag-Te Emmy deposit (Khabarovsk Territory, Russia). In Emmy deposit, sulfosalts primarily represent goldfieldite, probably corresponding to a high-sulfidation (HS) mineral association replaced bytennantite–tetrahedrite group minerals. The latter is associated with tellurides and native tellurium, corresponding to an intermediate-sulfidation (IS)-type ore assemblage and suggesting an increasing influx of Te, Sb, and As in the system. Goldfieldite is replaced by native tellurium and tellurides along its growth zones, and is characterized by oscillatory zoning. The replacement of goldfieldite by mercury, nickel, lead, and copper tellurides indicate a new influx of native gold, native tellurium, and gold–silver tellurides into the open mineral-forming system. At deeper levels of the Emmy deposit, an advanced argillic alteration assemblage includes aluminum phosphate–sulfate (APS) minerals, represented by members of the svanbergite–woodhouseite series. Element mapping of the studied APS mineral grains indicated three distinct areas recording the evolution of the hydrothermal system in the Emmy: an oscillatory-zoned margin enriched in sulfur, lead, and barium, corresponding to the late influx of IS state fluids related to gold and tellurides; an intermediate part, which is leached and corresponds to the HS mineralization stage; and the central part of the grains, which is enriched in cerium, calcium, and strontium, resulting from a replacement of magmatic apatite in the pre-ore alteration stage. The leached zone between the core and rim of the APS grains is related to a change in crystallization conditions, possibly due to the mixing processes of the fluids with meteoric water. Barite, found in the upper level of the advanced argillic hypogene alteration assemblage, is also characterized by oscillatory zoning, associated with the enrichment of individual zones in lead. Micron gold particles associated with barite are confined to their lead-enriched zones. The study of fluid inclusions in quartz within the Emmy deposit showed the hydrothermal ore process at a temperature of 236–337 °C. Homogenization temperatures for quartz–pyrite–goldfieldite mineral association vary within 337–310 °C and salinity varies within 0–0.18 wt.%NaCl equivalent, and for gold–silver–telluride–polymetallic mineral association, they decrease and vary within 275–236 °C and salinity slightly increases from 0.18 to 0.35 wt.%NaCl equivalent. This study demonstrates that the nature of oscillatory zoning in sulfosalts and sulfates in the Emmy deposit results from an external process. Such a process is of fundamental importance from a genetic point of view.

Compositions prepared on the basis of fine corundum and aluminophosphate binders modified with B 3+ , Cr 3+ , Mo 6+ , and Zr 4+ ions are considered. The influence of the ions listed on thermophysical properties of aluminophosphate compositions is studied. Results of comparative tests for the composites obtained in an arc plasmatron flow with estimation of surface melting temperature of the specimens are presented. Results of moisture adsorption studies of the composites with various relative humidity are shown.

We have investigated the preparation of high-surface-area mesoporous aluminophosphates by non-hydrolytic sol–gel method based on reactions of EtAlCl 2 with trialkylesters of phosphoric acid (OP(OR) 3 , R = Me, Et, i Pr, n Bu, in dry organic solvents. The condensations proceed by alkylchloride elimination. Various reaction and calcination conditions were examined. Porosity is obtained after calcination by removal of organic residual groups. This thermal processing at 300 °C of as-synthesized precursor gels leads to amorphous aluminophosphate xerogels with surface areas of 400–500 m 2  g –1 provided by small mesopores (2–8 nm). Changes in the coordination environment of aluminium from six- to four-coordinate are evidenced by shift of 27 Al MAS NMR resonances. Highlights Dichloroethylalane reacts with trialkylphosphates by alkylchloride elimination. Aluminophosphate gels are obtained from the non-hydrolytic sol-gel technique. Thermal processing at 300 °C leads to amorphous xerogels with surface areas of 400–500 m 2  g –1 . Porosity is composed of small mesopores (2–8 nm). Templating with Pluronic P123 significantly improves pore size distribution.