Aluminum Hydroxide Research Articles

Industrial aluminum hydroxides: Part 1. Phase composition and textural characteristics of industrial aluminum hydroxides/oxides

The most common component in the design of heterogeneous catalysts for oil refining and petrochemistry are aluminum oxides. Each type of hydrocarbon raw materials and technological process corresponds to the optimal characteristics of aluminum oxide supports and catalysts: specific surface area, pore size, phase and impurity compositions. Due to the trend towards import substitution, the research of domestic producers of aluminum hydroxide used for the synthesis of aluminum oxides is becoming more relevant. In this work, domestic industrial samples of aluminum hydroxides were studied by methods of X-ray phase analysis, thermogravimetry combined with differential scanning calorimetry, low-temperature nitrogen adsorption and elemental analysis. It is established that the objects of research are most often phase-inhomogeneous, in which impurities of iron, silicon and calcium are present. The influence of the degree of crystallization and the size of the coherent scattering regions of aluminum hydroxides, mainly with the structure of boehmite and, in some cases, containing bayerite, on the textural characteristics of the resulting aluminum oxides is shown.

Analytical Insights into Protein-Alum Interactions and Their Impact on Conformational Epitope.

Several alum-adjuvanted vaccines have been licensed in the past 40 years. Despite its extensive and continuous use, the immune mechanism of action of alum adjuvants is not yet completely understood. Many different variables during the formulation process have been assessed as critical for alum-adjuvanted vaccines, although most of them are still not yet fully understood. The absence of a clear understanding of all the possible variables regulating the mechanism of action and the behavior that alum adjuvant imposes on the protein antigen may also be related to analytical challenges. For this reason, there is an urgent need for a fast and simple tool that is possible without a preliminary sample manipulation and is able to control the amount and the degree of antigen adsorption levels and their consistency across different production processes. This work attempts to develop new analytical tools with the aim of directly quantifying and assessing both the content and/or the purity of formulated alum-adsorbed antigens, without any preliminary sample manipulation (e.g., antigen desorption) being reported. In addition, the different confirmation/behavior in terms of the response to specific monoclonal antibodies in the presence of different ratios of alum-OH adsorbent antigens have been investigated. As a proxy to develop new analytical tools, three recombinant protein adsorbed models were used as follows: Neisseria adhesin A (NadA), Neisserial Heparin Binding Antigen (NHBA), and factor H binding protein (fHbp) as antigens, as well as aluminum hydroxide (AH) as an adjuvant system. The selection of the adjuvanted system model was dictated due to the substantial quantity of the literature regarding the protein structure and immunological activities, meaning that they are well characterized, including their adhesion rate to alum. In conclusion, three different analytical tools were explored to quantify, detect, and study the behavior of antigens in the presence of the alum adjuvant.

Batch electrocoagulation system for the treatment of Borneo urban river in relation to the industrial zone

Urbanization activities on Borneo Island have degraded the water quality of some urban rivers due to increased anthropogenic activities which leading to elevated levels of total organic carbon (TOC) and reduced access to clean water sources. As such, this study aims to develop a batch electrocoagulation treatment system to reduce the TOC levels in Borneo urban river for domestic consumption. Correspondingly, this study analyses the effect of electric current and residence time on TOC reduction efficiency. Subsequent, this study has found that the TOC levels in treated urban river water met domestic consumption safety standard by utilizing a batch electrocoagulation treatment system at 5 A of electric current and 25 minutes of residence time. The treatment system achieves 82.83% of maximum TOC reduction efficiency by decreasing the initial TOC levels from 5.65 mg/L to 0.97 mg/L. The energy operating cost analysis done in this study has reported that electrocoagulation treatment system could generate 116.51 g Al(OH)3 per meter cubic of urban river water at a cost of United States Dollars (USD) 0.32 per m3. Additionally, the reduction of TOC levels in urban river by using in-situ aluminium hydroxide coagulants follows Freundlich isotherm model with a regression coefficient of 0.99, thus, exhibiting a multilayer adsorption. The aluminium hydroxide coagulants could reduce TOC from urban river at 1.40 min−1 of adsorption rate and 0.20 mg/g of maximum adsorption capacity. From the energy dispersive X-ray analysis conducted, this study has observed the presence of electrocoagulation flocs that are constituted with aluminium hydroxide coagulants and carbon element which indicated the occurrence of adsorption process. Overall, this study demonstrates that the batch electrocoagulation treatment system could be utilized to reduce the TOC level from Borneo urban river with an adsorption process which is deemed suitable for domestic consumption at a reasonable cost.

Enhancing flame and electrical surface discharge resistance in silicone rubber composite insulation through aluminium hydroxide, clay, and glass fibre additives

Silicone rubber (SR) is a leading polymer used in electrical outdoor insulation applications due to its superior hydrophobic characteristics. However, the low flame and electrical surface discharge resistance of SR limit its broad viability and challenge its integrity in severe outdoor working conditions. This work attempts to explore the flame retardancy and surface discharge characteristics of SR co-filled with aluminium hydroxide (ATH), nanoclay montmorillonite (MMT), and chopped glass fibre (GF). Results indicate that the incorporation of ATH/MMT/GF could assist in improving the fire and surface discharge resistance of the SR material. It is noted that the maximum average rate of heat emission (MARHE) and total smoke production (TSP) are measured at 24.93 kW/m2 and 0.48 m2 in SRE, relative to 61.29 kW/m2 and 6.02 m2 in SRB. Using finite element analysis (FEA), the maximum electric field strength is computed at 4.66 × 106 V/m in the air gap coupled with a high-voltage (HV) plate and sample. SRE exhibits a higher partial discharge inception voltage (PDIV) value of 2.32 kVrms than its counterparts, while the maximum discharge magnitude (Qmax) is computed at 7095 pC, relative to 7746 pC in SRB. SRE emerges as a preferable SR composite to be used in electrical insulation applications with excellent flame and surface discharge resistance characteristics.

Silk fibroin-based hydrogel as injectable carrier for prolonged immunization of plant-based COVID-19 subunit vaccine

Silk fibroin (SF)-based hydrogel was prepared to serve as an injectable carrier, aimed at prolonging the immunization effect of the plant-derived vaccine for the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). This vaccine consists of the Receptor-Binding Domain (RBD) linked with the Fragment Crystallizable (Fc) region of Human Immunoglobulin G 1 (IgG1), also referred to as the RBD-Fc vaccine. The formulation also includes Aluminium hydroxide gel (Alum). Ex-vivo experiments demonstrated that both the SARS-CoV-2 RBD-Fc-loaded SF hydrogel (RBD-Fc/SF hydrogel) and the Alum-adjuvanted SARS-CoV-2 RBD-Fc-loaded SF hydrogel (Alum-RBD-Fc/SF hydrogel) indicated localized retention. This resulted in a controlled and prolonged release of 75% and 25% over a period of 60 days, respectively. This facilitated continuous interaction between the immune system and the viral peptide, specifically the RBD, which could have significant implications for geometric mean titer (GMT). In immunization studies, the RBD-Fc/SF hydrogel and Alum-RBD-Fc/SF hydrogel had induced a more prolonged and stronger immunogenic response of mouse-RBD-specific IgG titer and IgG subtypes (IgG1 and IgG2a). The specific IgG1 and IgG2a titers of RBD-Fc/SF hydrogel (with GMTs of 67,559 and 1,056, respectively) and Alum-RBD-Fc/SF hydrogel (with GMTs of 155,209 and 1,838, respectively) were superior to the RBD-Fc vaccine without SF hydrogel (with GMTs of 3200 and 200, respectively). Furthermore, they were comparable to the responses elicited by commercial Alum-adjuvants currently in use (with GMTs of 51,200 and 4,850, respectively). Additionally, a concentration of 0.1%w/v SF exhibited significant adjuvant properties by augmenting the secretion of various cytokines. For instance, it enhanced the secretion of Interleukin-6 (IL-6) to 88.02 pg/mL, which is comparable to the secretion induced by commercial Alum adjuvants (39.48 pg/mL). These findings suggest that SF hydrogel-based vaccine formulations could enhance humoral immunity and induce long-lasting immune responses. However, further investigations are required to assess the neutralizing potential of the antibodies produced against SARS-CoV-2 and its variants. The prospects and outcomes of SF hydrogel-based vaccine formulations indicate their potential as a next-generation vaccine platform. Such innovative strategies could be pivotal in the fight against COVID-19 and other infectious diseases.

Effect and mechanism of acupuncture on airway smooth muscle relaxation during acute asthma attack in rats.

To explore the effect and mechanism of acupuncture at "Feishu" (BL 13) and "Dingchuan" (EX-B 1), and "Kongzui" (LU 6) and "Yuji" (LU 10) for relaxing the airway smooth muscle in the rats during acute asthma attack and compare the effect among the two pairs of acupoints and the acupoints combination. Forty SD male rats with SPF grade were randomly divided into a blank group, a model group, a pair-point A group (acupuncture at "Feishu" [BL 13] and "Dingchuan" [EX-B 1]), a pair-point B group (acupuncture at "Kongzui" [LU 6] and "Yuji" [LU 10]) and a point combination group (acupuncture at "Feishu" [BL 13] , "Dingchuan" [EX-B 1], "Kongzui" [LU 6] and "Yuji" [LU 10]), with 8 rats in each group. Except the rats in the blank group, the model of acute asthma attack was induced by ovalbumin (OVA) combined with aluminum hydroxide gel in the rest groups. Started on the 15th day of modeling, except in the blank group and the model group, acupuncture was delivered in the other groups, 30 min in each intervention, once daily, for 14 days. In each group, the latent period of asthma inducing was measured; the lung resistance (LR) and dynamic lung compliance (Cdyn) were determined using lung function detector; the levels of endothelin-1 (ET-1), tumor necrosis factor-α (TNF-α), cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in serum and bronchoalveolar lavage fluid (BALF) were measured by ELISA; with Masson staining and electron microscopy adopted, the morphology and ultrastructure of airway smooth muscle of the rats were observed; the mRNA and protein expressions of ET-1 and beta-2 adrenergic receptor (β2-AR) were detected by quantitative real-time fluorescence and Western blot, respectively. Compared with the blank group, the latent period of asthma inducing was shortened (P<0.05), RL increased and Cdyn decreased (P<0.05) with the different concentrations of methacholine (0.025 mg/kg, 0.05 mg/kg, 0.1 mg/kg, 0.2 mg/kg) in the model group. In the pair-point A group, the pair-point B group and the point combination group, the latent period of asthma inducing was prolonged (P<0.05), RL decreased and Cdyn increased (P<0.05) with different concentrations of methacholine when compared with those in the model group; and the latent period of asthma inducing in the point combination group was longer than that in the pair-point A group (P<0.05). Compared with the blank group, the levels of ET-1, TNF-α and cGMP in the serum and BALF were elevated (P<0.05), and those of cAMP reduced (P<0.05) in the model group. The levels of ET-1, TNF-α and cGMP in the serum and BALF were reduced (P<0.05), and those of cAMP elevated (P<0.05) in the pair-point A group, the pair-point B group and the point combination group when compared with those in the model group. In the blank group, the lung tissue was normal structurally. In the model group, the collagen fibers were proliferated increasingly, the smooth muscle was thickened, the mitochondria were swollen, and their cristae disrupted and reduced massively. In the pair-point B group, the collagen fibers were proliferated, the smooth muscle was thicker compared with that in the blank group, the mitochondria were mildly swollen and their cristae disrupted partially. In the pair-point A group and the point combination group, the lung tissue changes were obviously alleviated in comparison with the model group, the mitochondria were slightly swollen and their cristae disrupted occasionally. Compared with the blank group, the mRNA and protein expression of ET-1 increased and that of β2-AR decreased in the lung tissue of the model group (P<0.05). In the pair-point A group, the pair-point B group and the point combination group, the mRNA and protein expression of ET-1 was reduced and that of β2-AR elevated in the lung tissue when compared with those in the model group (P<0.05). In comparison with the pair-point A group, the mRNA expression of β2-AR was elevated in the point combination group (P<0.05). When compared with the pair-point B group, the mRNA expression of β2-AR increased, the protein expression of ET-1 decreased (P<0.05) in the point combination group. Acupuncture at "Feishu" (BL 13) and "Dingchuan" (EX-B 1), "Kongzui" (LU 6) and "Yuji" (LU 10), two pairs of acupoints relieves the airway smooth muscle spasm in the rats during acute asthma attack, which may be related to inhibiting the mRNA and protein expression of ET-1 to reduce the excretion of ET-1 and TNF-α; while enhancing the mRNA and protein expression of β2-AR to balance the levels of cAMP and cGMP. The effect is optimal when acupuncture is delivered at two pairs of acupoints simultaneously.

An inactivated whole-virion vaccine for Enterovirus D68 adjuvanted with CpG ODN or AddaVax elicits potent protective immunity in mice

Enterovirus D68 (EV-D68), a pathogen that causes respiratory symptoms, mainly in children, has been implicated in acute flaccid myelitis, which is a poliomyelitis-like paralysis. Currently, there are no licensed vaccines or treatments for EV-D68 infections. Here, we investigated the optimal viral inactivation reagents, vaccine adjuvants, and route of vaccination in mice to optimize an inactivated whole-virion (WV) vaccine against EV-D68. We used formalin, β-propiolactone (BPL), and hydrogen peroxide as viral inactivation reagents and compared their effects on antibody responses. Use of any of these three viral inactivation reagents effectively induced neutralizing antibodies. Moreover, the antibody response induced by the BPL-inactivated WV vaccine was enhanced when adjuvanted with cytosine phosphoguanine oligodeoxynucleotide (CpG ODN) or AddaVax (MF59-like adjuvant), but not with aluminum hydroxide (alum). Consistent with the antibody response results, the protective effect of the inactivated WV vaccine against the EV-D68 challenge was enhanced when adjuvanted with CpG ODN or AddaVax, but not with alum. Further, while the intranasal inactivated WV vaccine induced EV-D68-specific IgA antibodies in the respiratory tract, it was less protective against EV-D68 challenge than the injectable vaccine. Thus, an injectable inactivated EV-D68 WV vaccine prepared with appropriate viral inactivation reagents and an optimal adjuvant is a promising EV-D68 vaccine.

Halogen‐free boron‐based hybrid system for enhancing flame retardancy, mechanical and thermal properties of epoxy

AbstractThis study aims to increase the flame retardancy of epoxy‐based composites by using various flame retardants together with colemanite filler (CLM), which is a very mineral‐rich boron type. As a flame retardant, aluminum hydroxide (Al(OH)3) and boron‐containing compounds: borax (BRX) and natural minerals (tincal (TNC) and colemanite (CLM)), as well as barium metaborate (BaMB) synthesized by us were used. Scanning electron microscopy (SEM), x‐ray powder diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), contact angle (CA), and particle size analysis were used to characterize the composites and additives. All boron compounds increased the thermal stability of the composites. Except for the ER/CLM‐BaMB composite, other composites' surface contact angles were over 90°. In terms of both combustion and thermal properties, the best CLM‐BaMB‐Al(OH)3‐TNC ratio was determined as 15:5:15:15. The tensile strength, self‐extinguishing time, estimated and experimental Limited Oxygen Index (LOI) values for this composite were determined as 96 MPa, 65 s, 29.6%, and 25%, respectively. In addition, ANOVA was applied to determine the effect of hybrid filler type and different weight ratios on the mechanical properties of composites.

MDCK-Adaptive Mutation of A169S Changes Glycosylation Pattern of Hemagglutinin and Enhances MDCK-Based H7N9 Vaccine Virus Production without Loss of Antigenicity and Immunogenicity.

The adaptation of egg-derived H7N9 candidate vaccine virus (CVV) in the mammalian cell line is an approach to developing a high-growth virus strain for the mass production of vaccine manufacturing. The adaptive mutations that occur in hemagglutinin (HA) are critical to the activity and potency of the vaccine virus. Previously, we identified a new mutation of A169S in the HA protein of an MDCK-adapted H7N9 vaccine virus (A/Anhui/2013, RG268); however, whether and how this mutation affects vaccine potency remain to be investigated. In this study, we serially passaged RG268 in MDCK cells and found that the HA titer and the TCID50 of the passaged virus RG268-M5 were 4-fold (HA units/50 μL) and 3.5-fold (log10 TCID50/mL) higher than those of the original CVV. By inspecting tandem MS spectra, we identified a new glycosylation site at N167 near the receptor binding site of the HA protein of RG268-M5. Flow cytometry results revealed that RG268-M5 could efficiently infect MDCK cells and initiate viral protein replication as well as that of RG268. Though the new glycosylation site is in the antigenic epitope of viral HA protein, the HI assay result indicated that the antigenicity of RG268-M5 was similar to RG268. Additionally, immunizing mice with RG268-M5 mixed aluminum hydroxide could induce potent antibody responses against the homologous and heterologous H7N9 viruses in vitro whereas the titers were comparable with those from the RG268 group. These results provide in-depth structural information regarding the effects of site-specific glycosylation on virus properties, which have implications for novel avian influenza vaccine development.

Evaluation of different types of adjuvants in a malaria transmission-blocking vaccine

Adjuvants are critical components for vaccines, which enhance the strength and longevity of the antibody response and influence the types of immune response. Limited research has been conducted on the immunogenicity and protective efficacy of various adjuvants in malaria transmission-blocking vaccines (TBVs). In this study, we formulated a promising TBV candidate antigen, the P. berghei ookinete surface antigen PSOP25, with different types of adjuvants, including the TLR4 agonist monophosphoryl lipid A (MPLA), the TLR9 agonist cytosine phosphoguanosine oligodeoxynucleotides (CpG ODN 1826) (CpG), a saponin adjuvant QS-21, aluminum hydroxide (Alum), and two combination adjuvants MPLA + QS-21 and QS-21 + CpG. We demonstrated that adjuvanted vaccines results in elevated elicited antibody levels, increased proliferation of plasma cells, and efficient formation of germinal centers (GCs), leading to enhanced long-term protective immune responses. Furthermore, CpG group exhibited the most potent inhibition of ookinete formation and transmission-blocking activity. We found that the rPSOP25 with CpG adjuvant was more effective than MPLA, QS-21, MPLA + QS-21, QS-21 + CpG adjuvants in dendritic cells (DCs) activation and differentiation. Additionally, the CpG adjuvant elicited more rubust immune memory response than Alum adjuvant. CpG and QS-21 adjuvants could activate the Th1 response and promote the secretion of IFN-γ and TNF-α. PSOP25 induced a higher number of Tfh cells in splenocytes when combined with MPLA, CpG, and QS-21 + CpG; and there was no increase in these cell populations when PSOP25 was administered with Alum. In conclusion, CpG may confer enhanced efficacy for the rPSOP25 vaccine, as evidenced by the ability of the elicited antisera to induce protective immune responses and improved transmission-blocking activity.

Utilizing the Adsorbability of Pseudoboehmite for Tailoring the Stability of an Aluminum Sulfate Alkali-free Accelerator for Shotcrete.

Shotcrete is widely used in tunnels, bridges, culverts, and other large-scale projects. The accelerator is an additive employed to expedite the setting time of shotcrete. Previous research primarily concentrated on enhancing the early strength of accelerators, whereas their long-term stability has been inadequately investigated. In this study, pseudoboehmite (PB) and amorphous aluminum hydroxide (AAH) were incorporated into the accelerator to enhance its stability over a period of 90 days without any signs of crystallization or delamination. Furthermore, the accelerator exhibited an initial setting time of 170 s, a final setting time of 550 s, and a compressive strength of 11.58 MPa after 1 day. The mechanism of effects was studied by isothermal calorimetry, FTIR, XRD, TG-DTG, and SEM analysis. The enhancement in stability is attributed to the distinctive adsorption and thixotropic properties of PB, which facilitate the formation of an electrical double-layer structure in acidic solutions. The expedited setting and hardening are primarily due to the equilibrium between Al3+, SO42-, and Ca2+ ions, which accelerates the hydration process of cement. This research offers a methodology for developing a high-performance, alkali-free liquid accelerator.

Characterization of Peat Water Electrocoagulation Flocs from Sarawak Southern Region

Sarawak located in Borneo is endowed with the vast availability of peat water sources, particularly for the state southern region. Several investigations have shown that electrocoagulation treatment with aluminium electrodes is feasible to treat peat water in which the quality is comparable to the National Water Quality Standard (NWQS). Even though electrocoagulation treatment is feasible to treat peat water, the characteristics of peat water electrocoagulation flocs have not been reported. As such, this study aims to investigate the characteristics of the electrocoagulation flocs from peat water derived from the Sarawak southern region by using batch electrocoagulation treatment. The objectives of this study are to conduct an experimental study analysis of and identify the minerals on the electrocoagulation flocs along with operating energy cost analysis of peat water batch electrocoagulation treatment. Consequently, this study has found that reaction time and current density affect the production of flocs in which the amount of flocs increases with the increasing reaction time and current density. The flocs produced are found to consist of a large fraction of oxygen (O), carbon (C), iron (Fe), and aluminium (Al) along with a small fraction of potassium (K), magnesium (Mg), calcium (Ca) and Silicon (Si). The presence of Al observed in the flocs is due to the aluminium hydroxide generated during the electrocoagulation process. The total operating cost for peat electrocoagulation with a current density of 5A and reaction time of 20 minutes is about RM0.31 per m3. As a result, the electrocoagulation of peat water process is able to treat peat water as well as produce flocs in which earth elements and heavy metals could be recovered.

A superior heterologous prime-boost vaccination strategy against COVID-19: A bivalent vaccine based on yeast-derived RBD proteins followed by a heterologous vaccine.

Various vaccines have been challenged by SARS-CoV-2 variants. Here, we reported a yeast-derived recombinant bivalent vaccine (Bivalent wild-type [Wt]+De) based on the wtand Delta receptor-binding domain (RBD). Yeast derived RBD proteins based on the wtand Delta mutant were used as the prime vaccine. It was found that, in the presence of aluminium hydroxide (Alum) and unmethylated CpG-oligodeoxynucleotides (CpG) adjuvants, more cross-protective immunity against SARS-CoV-2 prototype and variants were elicited by bivalent vaccine than monovalent wtRBD or Delta RBD. Furthermore, a heterologous boosting strategy consisting of two doses of bivalent vaccines followed by one dose adenovirus vectored vaccine exhibited cross-neutralization capacity and specific T cell responses against Delta and Omicron (BA.1 and BA.4/5) variants in mice, superior to a homologous vaccination strategy. This study suggested that heterologous prime-boost vaccination with yeast-derived bivalent protein vaccine could be a potential approach to address the challenge of emerging variants.

Microencapsulation of Al-Si-Fe alloys for high-temperature thermal storage with excellent thermal cycling performance

Metal-based phase change heat storage materials have become a potent candidate to regulate supply and demand of thermal energy due to their high conductivity, latent heat and stability. With the development of high-efficiency energy storage systems, materials with higher phase change temperatures are in demand urgently for more effective energy storage, which had not been achieved. Herein, the industrial Al-Si-Fe alloy with phase change temperature of 869 °C was chosen as heat storage material in this research. Furthermore, to prevent the alloy from the inherent problems such as liquid leakage, oxidation and corrosion at high temperature, a new and simple strategy was developed to micro-capsulate the alloy. The prepared process of microcapsules involved two steps: pre-coated of aluminum hydroxide along with hydrothermal carbon and heat treatment in nitrogen atmosphere. The composition, morphology, and thermal performance of the microcapsules were characterized by XRD, SEM, TEM, and TG-DSC. The results indicated the shell below 1 μm was composed of α-Al2O3 strengthened by network AlN fibers formed through the V-S mechanism. The latent heat of microcapsules reached 187.6 J·g−1 which was 82.9 % relative to raw material. Moreover, the total latent heat of the microcapsules did not change much after 300 cycles between 500 and 900 °C, although the phase transition behavior was altered. Overall, this research provides a novel idea for the encapsulation technology and the application of thermal energy storage materials from preparation and structure, which is conducive to promote the application of high-temperature phase change materials.

Vaccination with parasite-specific TcTASV proteins combined with recombinant baculovirus as a delivery platform protects against acute and chronic Trypanosoma cruzi infection.

Chagas' is a neglected disease caused by the eukaryotic kinetoplastid parasite, Trypanosoma cruzi. Currently, approximately 8 million people are infected worldwide, most of whom are in the chronic phase of the disease, which involves cardiac, digestive, or neurologic manifestations. There is an urgent need for a vaccine because treatments are only effective in the initial phase of infection, which is generally underdiagnosed. The selection and combination of antigens, adjuvants, and delivery platforms for vaccine formulations should be designed to trigger mixed humoral and cellular immune responses, considering that T. cruzi has a complex life cycle with both intracellular and bloodstream circulating parasite stages in vertebrate hosts. Here, we report the effectiveness of vaccination with a T. cruzi-specific protein family (TcTASV), employing both recombinant proteins with aluminum hydroxide and a recombinant baculovirus displaying a TcTASV antigen at the capsid. Vaccination stimulated immunological responses by producing lytic antibodies and antigen-specific CD4+ and CD8+ IFNɣ secreting lymphocytes. More than 90% of vaccinated animals survived after lethal challenges with T. cruzi, whereas all control mice died before 30 days post-infection. Vaccination also induced a strong decrease in chronic tissue parasitism and generated immunological memory that allowed vaccinated and infected animals to control both the reactivation of the infection after immunosuppression and a second challenge with T. cruzi. Interestingly, inoculation with wild-type baculovirus partially protected the mice against T. cruzi. In brief, we demonstrated for the first time that the combination of the baculovirus platform and the TcTASV family provides effective protection against Trypanosoma cruzi, which is a promising vaccine for Chagas disease.

Detoxification of chromium slag using corn stalk for the hierarchical preparation of ultrafine aluminum hydroxide and iron hydroxide

The harmless treatment and resource utilization of chromite ore processing residue (COPR), a consequential byproduct of chromate production, carry profound significance. In this study, corn stalk, an agricultural waste, was used to generate reducing substances through high-temperature and vacuum treatments and was successfully used to detoxify COPR. The acid leaching method combined with multi-step purification was employed to extract iron and aluminum, two crucial metallic elements, from COPR. The successful preparation of iron hydroxide and ultrafine aluminum hydroxide (ATH) was achieved. The prepared ATH has an average particle size of 8.124 μm, with a highly uniform distribution, enabling it to be a promising environmentally friendly inorganic flame retardant. This study not only effectively addresses the issue of pollution caused by COPR but also presents a novel approach to utilizing industrial and agricultural wastes, thereby promoting the maximization of resource utilization.

Novel adjuvants in allergen-specific immunotherapy: where do we stand?

Type I hypersensitivity, or so-called type I allergy, is caused by Th2-mediated immune responses directed against otherwise harmless environmental antigens. Currently, allergen-specific immunotherapy (AIT) is the only disease-modifying treatment with the potential to re-establish clinical tolerance towards the corresponding allergen(s). However, conventional AIT has certain drawbacks, including long treatment durations, the risk of inducing allergic side effects, and the fact that allergens by themselves have a rather low immunogenicity. To improve AIT, adjuvants can be a powerful tool not only to increase the immunogenicity of co-applied allergens but also to induce the desired immune activation, such as promoting allergen-specific Th1- or regulatory responses. This review summarizes the knowledge on adjuvants currently approved for use in human AIT: aluminum hydroxide, calcium phosphate, microcrystalline tyrosine, and MPLA, as well as novel adjuvants that have been studied in recent years: oil-in-water emulsions, virus-like particles, viral components, carbohydrate-based adjuvants (QS-21, glucans, and mannan) and TLR-ligands (flagellin and CpG-ODN). The investigated adjuvants show distinct properties, such as prolonging allergen release at the injection site, inducing allergen-specific IgG production while also reducing IgE levels, as well as promoting differentiation and activation of different immune cells. In the future, better understanding of the immunological mechanisms underlying the effects of these adjuvants in clinical settings may help us to improve AIT.

Vaccine Based on Recombinant Fusion Protein Combining Hepatitis B Virus PreS with SARS-CoV-2 Wild-Type- and Omicron-Derived Receptor Binding Domain Strongly Induces Omicron-Neutralizing Antibodies in a Murine Model.

COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a recurrent endemic disease affecting the whole world. Since November 2021, Omicron and its subvariants have dominated in the spread of the disease. In order to prevent severe courses of disease, vaccines are needed to boost and maintain antibody levels capable of neutralizing Omicron. Recently, we produced and characterized a SARS-CoV-2 vaccine based on a recombinant fusion protein consisting of hepatitis B virus (HBV)-derived PreS and two SARS-CoV-2 wild-type RBDs. To develop a PreS-RBD vaccine which induces high levels of Omicron-specific neutralizing antibodies. We designed, produced, characterized and compared strain-specific (wild-type: W-PreS-W; Omicron: O-PreS-O), bivalent (mix of W-PreS-W and O-PreS-O) and chimeric (i.e., W-PreS-O) SARS-CoV-2 protein subunit vaccines. Immunogens were characterized in vitro using protein chemical methods, mass spectrometry, and circular dichroism in combination with thermal denaturation and immunological methods. In addition, BALB/c mice were immunized with aluminum-hydroxide-adsorbed proteins and aluminum hydroxide alone (i.e., placebo) to study the specific antibody and cytokine responses, safety and Omicron neutralization. Defined and pure immunogens could be produced in significant quantities as secreted and folded proteins in mammalian cells. The antibodies induced after vaccination with different doses of strain-specific, bivalent and chimeric PreS-RBD fusion proteins reacted with wild-type and Omicron RBD in a dose-dependent manner and resulted in a mixed Th1/Th2 immune response. Interestingly, the RBD-specific IgG levels induced with the different vaccines were comparable, but the W-PreS-O-induced virus neutralization titers against Omicron (median VNT50: 5000) were seven- and twofold higher than the W-PreS-W- and O-PreS-O-specific ones, respectively, and they were six-fold higher than those of the bivalent vaccine. Among the tested immunogens, the chimeric PreS-RBD subunit vaccine, W-PreS-O, induced the highest neutralizing antibody titers against Omicron. Thus, W-PreS-O seems to be a highly promising COVID-19 vaccine candidate for further preclinical and clinical evaluation.

Castor oil‐based polyurethane ternary composites with enhanced thermal conductivity and mechanical properties by using liquid metal as second filler

AbstractWith the miniaturization, high frequency of electronic devices, and low‐carbon and sustainable development, higher requirements are put forward for thermal conductive polyurethane composites in terms of comprehensive performance and renewable raw materials. Herein, choosing bio‐based polyurethane (PU) derived from castor oil as matrix, and liquid metal (LM) and aluminum hydroxide (ATH) as hybrid thermal conductive filler, castor oil‐based PU composites were developed via high‐speed rotation and in‐situ polymerization method. The LM‐ATH hybrid filler displayed a synergistic enhancement effect on the thermal conductivity of composites due to the presence of LM‐bridging significantly improved the effective contact probability between ATH fillers. The thermal conductivity of 50LM‐ATH/PU reached 1.69 Wm−1 K−1, which was 9.9 times and 1.4 times higher than that of pure PU and 50ATH/PU, respectively. Notably, the 50LM‐ATH/PU exhibited outstanding mechanical properties including tensile strength up to 4.0 MPa and adhesion strength up to 7.9 MPa, especially elongation at break up to 120% which was improved by 200% compared with 50ATH/PU (40%). Additionally, the composite possessed excellent electric insulation, thermal stability, and inflaming retarding properties, showing great application potential in the electronic devices field.Highlights Castor oil‐based PU composites with ATH‐LM hybrid filer were developed. LM‐ATH hybrid filler of 2:8 promoted the thermal conductivity of composites. Hybrid filler than ATH‐endowed composites with better mechanical properties. The ATH‐LM/PU exhibited excellent electric insulation.

Evaluation of long-term immune response in cattle to botulism using a recombinant E. coli bacterin formulated with Montanide™ ISA 50 and aluminum hydroxide adjuvants

Botulism is a severe disease caused by potent botulinum neurotoxins (BoNTs) produced by Clostridium botulinum. This disease is associated with high-lethality outbreaks in cattle, which have been linked to the ingestion of preformed BoNT serotypes C and D, emphasizing the need for effective vaccines. The potency of current commercial toxoids (formaldehyde-inactivated BoNTs) is assured through tests in guinea pigs according to government regulatory guidelines, but their short-term immunity raises concerns. Recombinant vaccines containing the receptor-binding domain have demonstrated potential for eliciting robust protective immunity. Previous studies have demonstrated the safety and effectiveness of recombinant E. coli bacterin, eliciting high titers of neutralizing antibodies against C. botulinum and C. perfringens in target animal species. In this study, neutralizing antibody titers in cattle and the long-term immune response against BoNT/C and D were used to assess the efficacy of the oil-based adjuvant compared with that of the aluminum hydroxide adjuvant in cattle. The vaccine formulation containing Montanide™ ISA 50 yielded significantly higher titers of neutralizing antibody against BoNT/C and D (8.64 IU/mL and 9.6 IU/mL, respectively) and induced an immune response that lasted longer than the response induced by aluminum, extending between 30 and 60 days. This approach represents a straightforward, cost-effective strategy for recombinant E. coli bacterin, enhancing both the magnitude and duration of the immune response to botulism.