Effect Of Mn2 Research Articles

Effect of Mn2+ concentration on the growth of δ-MnO2 crystals under acidic conditions

δ-MnO2 is an important component of environmental minerals and is among the strongest sorbents and oxidants. The crystalline morphology of δ-MnO2 is one of the key factors affecting its reactivity. In this work, δ-MnO2 was initially synthesized and placed in an acidic environment to react with Mn2+ and undergo a crystalline transformation. During the transformation of crystalline δ-MnO2, kinetic sampling was conducted, followed by analyses of the structures and morphologies of the samples. The results showed that at pH 2.5 and 4, δ-MnO2 nanoflakes spontaneously self-assembled into nanoribbons via edge-to-edge assembly in the initial stage. Subsequently, these nanoribbons attached to each other to form primary nanorods through a face-to-face assembly along the c-axis. These primary nanorods then assembled along the (001) planes and lateral surfaces, achieving further growth and thickening. Since a lower pH is more favorable for the formation of vacancies in δ-MnO2, δ-MnO2 can rapidly adsorb Mn2+ directly onto the vacancies to form tunnel walls. At the same time, the rapid formation of the tunnel walls leads to a quick establishment of hydrogen bonding between adjacent nanoribbons, enabling the assembly of these nanoribbons into primary nanorods. Therefore, in a solution with the same concentration of Mn2+, the structure transformation and morphology evolution of δ-MnO2 to α-MnO2 occur faster at pH 2.5 than at pH 4. These findings provide insights into the mechanism for crystal growth from layer-based to tunnel-based nanorods and methods for efficient and controlled syntheses of nanomaterials.

Effect of Mn2+ substitution on the dielectric properties of NaMg(PO3)3 ceramics at microwave and terahertz frequencies

In this study, NaMg1-xMnx(PO3)3 (0.00 ≤ x ≤ 0.0625) ceramics with low dielectric constant were prepared via the solid-state reaction method. The effects of Mn2+ substitution on the microstructure and dielectric properties (at microwave and terahertz frequencies) of the NaMg(PO3)3 ceramics were studied by means of the Rietveld refinement, morphology, and ionic polarizability analysis. It is obtained that the NaMg0.0975Mn0.025(PO3)3 ceramic sintered at 880 °C for 4 h exhibited optimal dielectric properties at microwave frequencies, where εr = 4.585, Q × f = 48,313 GHz (@17.228 GHz), and τf = −40.83 ppm/°C. The Q × f and τf values were changed by 74.2 % and 27.8 %, as compared to the values of 27,728 GHz and −56.52 ppm/°C for the pure NaMg(PO3)3 ceramic, respectively. For terahertz frequencies (0.2–1.0 THz), the εr values were decreased to 3.79–3.98, and the tanδ values were between 0.0203 and 0.1152. All the experimental results indicate that this system exhibits great potentials both at microwave and terahertz frequencies.

Effect of Mn2+ doping and DDAB-assisted postpassivation on the structural and optical properties of CsPb(Cl/Br)3 halide perovskite nanocrystals

Cesium lead halide perovskite (CsPbX3; X = Cl, Br, I) nanocrystals showing intense band-edge emission and high photoluminescence quantum yield are known to be a potential candidate for application in optoelectronic devices. However, controlling toxicity due to the presence of Pb2+ in lead-based halide perovskites is a major challenge for the environment that needs to be tackled cautiously. In this work, we have partially replaced Pb2+ with Mn2+ ions in the CsPb(Cl/Br)3 nanocrystals and investigated their impact on the structural and optical properties. The Rietveld refinement shows that CsPbCl2Br nanocrystals possess a cubic crystal structure with Pm 3̅ m space group, the Mn2+ doping results in the contraction of the unit cell. The CsPb(Cl/Br)3: Mn nanocrystals show a substantial change in the optical properties with an additional emission band at ∼588 nm through a d-d transition, changing the emission color from blue to pink. Here, a didodecyldimethylammonium bromide (DDAB) ligand that triggers both anion and ligand exchange in the CsPb(Cl/Br)3: Mn nanocrystals have been used to regulate the exchange reaction and tune the emission color of halide perovskites by changing the peak position and the PL intensities of band-edge and Mn2+ defect states. We have also shown that oleic acid helps in the desorption of oleylamine capping from the CsPb(Cl/Br)3: Mn nanocrystal surfaces and DDAB, resulting in the substitution of Cl− with Br− as well as provides capping with shorter branched length ligand which led to increase in the overall PL intensity by many folds.

The effect of supplementing freezing extender with Mn2+-, Zn2+- or Cu2+-nanosuccinate on select post-thaw characteristics of ram semen

The effects of Mn2+-, Zn2+- or Cu2+-nanosuccinate added to freezing extender on select post-thaw semen characteristics were determined in six Texel rams (aged 2–4 years) during seasonal anestrus (April-May). Ejaculates (n = 6 per ram) collected into an artificial vagina were divided into ten isovolumetric fractions each. Semen was diluted in lactose-yolk-tris-citrate-glycerin medium and nanosuccinates (Mn2+- and Zn2+-nanosuccinate: 0.0 (control), 2.5, 5.0 and 7.5 μg/l; Cu2+-nanosuccinate: 0.0 (control), 1.25, 2.5 and 3.75 μg/l) were added to semen extender. Extended semen was loaded into 0.25-ml straws and frozen in liquid nitrogen. After thawing, sperm motility parameters were determined with computer assisted semen analysis (CASA), and the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) was measured with a spectrophotometric technique. The addition of 5.0 μg/l of Mn2+- and Zn2+-nanosuccinate significantly increased the sperm progressive motility and both 2.5 and 5.0 μg/l improved sperm motion kinetics. Further, both nanosuccinates at a dose of 5.0 μg/l significantly decreased SOD activity and stimulated an increase in GPx and CAT activity in semen samples. Alternatively, the addition of Cu2+-nanosuccinate (highest dose) significantly reduced the progressive motility and velocity of ram spermatozoa, increased the percentage of sperm with acrosomal/head defects and seminal SOD activity, and depressed CAT (highest dose) and GPx (all doses) activity. In summary, the addition of Mn2+- and Zn2+-nanosuccinate to semen extender had beneficial effects on sperm motility/motion kinetics and structural integrity, whereas Cu2+-nanosuccinate generally had debilitating effects on the post-thaw semen characteristics in rams.

Effect of Mn2+ on RO membrane organic fouling: Insights into the complexation and interfacial interaction

RO process is commonly used to treat and reuse manganese-containing industrial wastewater. Nevertheless, even after undergoing multi-stage treatment, the secondary biochemical effluent still exhibits a high concentration of Mn2+ coupled with organics entering the RO system, leading to membrane fouling. In this work, we systematically analyze the RO membrane organic fouling processes and mechanisms, considering the coexistence of Mn2+ with humic acid (HA), sodium alginate (SA), bovine serum albumin (BSA) and their mixtures (HBS). The impact of Mn2+ on membrane fouling was HBS > SA > HA > BSA, controlling polysaccharide pollutant concentrations should be a priority for mitigating membrane fouling. In the presence of Mn2+ with HA, SA, or HBS, membrane fouling is primarily attributed to the complexation of organics and Mn2+ and the facilitation of interfacial interaction energy. RO membrane BSA fouling was not directly affected by Mn2+, the addition of Mn2+ induced a salting-out effect, leading to the deposition of BSA in a single molecular on the membrane. Simultaneously, adhesion energy hinders the deposition of BSA on the membrane, resulting in milder membrane fouling. This study provided the theoretical basis and suggestions for RO membrane organic fouling control in the presence of Mn2+.

Mn–Si synergistically co-doping adjusting microstructures and microwave-millimeter-wave dielectric properties of Y3Al5O12 garnet ceramics: Lattice occupancy and ligand distortion perspective

Y3-xMnxAl5-xSixO12 (x = 0.1–0.5) ceramics were fabricated through the high-temperature reaction method. The effects of Mn2+-Si4+ co-doping on lattice occupancy, ligand distortion and microwave dielectric properties of Y3Al5O12 garnet were inquired. Mn2+ ions successively occupy the lattice sites of Y3+ dodecahedron and Al3+ octahedron along with the increase of distortion degree of [AlO6] octahedron. In Y3-xMnxAl5-xSixO12, εr predominantly correlates with ionic polarizability, average bond ionicity (△fi) and Mn2+ ionic lattice occupation. The Q × f is primarily influenced by factors like relative density, lattice energy (U) and atomic packing fraction. Meanwhile, τf is associated with the distortion of octahedra, bond energy (E), and the bond valence between Y/Mn and O. Ultimately, the microwave and millimeter-wave dielectric properties of the Y2.8Mn0.2Al4.8Si0.2O12 ceramics excel with values of εr = 10.89, Q × f = 56,135 GHz@11 GHz (Q × f = 88200 GHz@25 GHz), and τf = -39.35 ppm/°C.

Effect of Mn2+ substitution on catalytic properties of Fe3-xMnxO4 nanoparticles synthesized via co-precipitation method

Mn-substituted magnetite samples Fe3-xMnxO4 (x = 0.0; 0.02; 0.05; 0.1; 0.15; 0.2; 0.25) were synthesized using the co-precipitation method. X-ray diffraction patterns confirmed the formation of pure, well-crystallized manganese ferrite with a cubic spinel structure. The crystallites size increases sharply for the minimum degrees of substitution, with a subsequent tendency to decrease with the growth of manganese ions content. The catalytic properties of Fe3-xMnxO4 were investigated for the degradation of oxytetracycline (ОТС) and inactivate E. coli. There is a correlation between particle size and catalytic activity. The Fe2.95Mn0.05O4 sample exhibited the highest catalytic activity in the destruction of OTC. The effect of electromagnetic heating (EMH) on the catalytic properties of iron oxides were investigated. The Fe2.9Mn0.1O4 sample with electromagnetic heating achieved 100 % efficiency in decomposing 5 mg/L of OTC. Fe3-xMnxO4 samples reduce the number of Gram-negative bacteria E. coli at concentrations of 104 and 106 CFU/mL. Electromagnetic heating experiments demonstrated high performance, achieving inactivation of 6 logs of E. coli in the presence of Fe2.98Mn0.02O4 and Fe2.95Mn0.05O4 catalysts within 135 minutes. Studies on ecotoxicity have shown that Daphnia magna is a sensitive bioindicator of residual H2O2 concentration. An increase in the Mn2+ content in the synthesized catalysts resulted in a decrease in the toxicity of purified water. The study suggests that Mn-substituted magnetite catalysts are effective materials for catalytic decomposition of OTC and inactivation of E. coli bacteria.

Effects of Mn2+ and flow speed on blood and physiological indexes of larvae GIFT tilapia (Oreochromis niloticus)

To assess the toxicological effects of heavy metal ions on fish at different flowing speeds within aquatic environments, we investigated the impact of Mn2+ and flow speed on the physiological parameters of juvenile GIFT tilapia (95.2±4.3g,15.1±0.21cm). The experiment design included four different levels of Mn2+ concentration: control group (0mg/L), 0.1mg/L, 0.5mg/L and 1mg/L, as well as three different flow speeds: control group (0 body length/second), low speed (1 body length/second), and high-speed group (2 body lengths/second). The main research findings were as follows: Mn2+ had varying effects on the hematological parameters of juvenile GIFT tilapia. As the levels of Mn2+ increased, there was a remarkable reduction in both the red blood cell (RBC) number and hemoglobin content of the fish(P<0.05). The activity of SOD, CAT, the level of MDA in the liver and white blood cell (WBC) number exhibited an initial increase followed by a subsequent decrease, with the highest levels observed mostly in the 0.5mg/L group. However, With the prolongation of Mn2+ exposure duration, a significant decline in levels of RBC, hemoglobin, CAT and SOD was observed. In most cases, the highest values of those, as mentioned earlier four physiological parameters were recorded at 24 hours, while the lowest values were recorded at 96 hours when exposed to the same Mn2+ level. However, MDA levels reached their peak at 48 hours. These findings suggested that lower levels of Mn2+ might enhance the immune capacity of tilapia, while higher levels could impede its immune and antioxidant functions. An increase in flow speed led to a significant elevation in both the RBC number and hemoglobin content of the GIFT tilapia at 30d(P<0.05), but flow speed had no significant impact on the WBC of the fish(P>0.05). Its effect on the fish antioxidant parameters also showed a certain induction, and there were significant correlations between the activity of SOD, CAT, the level of MDA, and flow speed (P<0.05). At the same flow speed, the prolonging water-flow-stimulus duration could not increase the levels of three antioxidant parameters(P>0.05). These findings could provide fundamental data for investigating the influence of heavy metal stress on fish ecotoxicology in aquatic environments and the artificial running water breeding of GIFT tilapia in Hebei province, China.

Effect of Mn2+ Substitution on Structural and Magnetic Properties of Co-Zn Ferrite

A series of Co0.8−x Mnx Zn0.2 Fe2O4 (x = 0.0 to 0.3 instep of 0.1) was prepared using the coprecipitation method. We investigated the structural and magnetic properties ascribed to the Mn+2 substitution. A single-phase spinel cubic ferrite nanoparticle with no extra peaks, supporting pure phase formation which confirmed by the X-ray analysis while the morphology studies has been examined using SEM, whose results showed an agglomeration to spherical shaped nanoparticles. The expected stoichiometry was confirmed by EDX analysis. By using VSM, the magnetic parameters measurements were performed at room temperature. The prepared samples exhibit soft ferrimagnetism from M–H loops. By increasing the Mn content, the saturation magnetization was found to decrease. Based on Neel’s two sublattice model of ferrimagnetism, and according to the cation distribution over A and B sites, the magnetic moments were estimated in all the samples from measured magnetic parameters. Based on the magnetic properties study which we obtained that revealed an enhancement in the magnetic properties of the prepared samples, that made them appropriate for practical applications in recording media and magnetic data storage ascribed to the Mn ions substitution.

Differences in the Effect of Mn2+ on the Reverse Osmosis Membrane Fouling Caused by Different Types of Organic Matter: Experimental and Density Functional Theory Evidence.

Landfill leachate from some sites contains a high concentration of Mn2+, which may cause reverse osmosis (RO) membrane fouling during RO treatment. In this study, the effect of Mn2+ on RO membrane fouling caused by typical organic pollutants (humic acid (HA), protein (BSA), and sodium alginate (SA)) was systematically investigated, and it was found that Mn2+ exacerbates RO membrane fouling caused by HA, SA, and HBS (mixture of HA + BSA + SA). When the Mn2+ concentration was 0.5 mM and 0.05 mM separately, the membrane fouling caused by HA and SA began to become significant. On the other hand, with for HBS fouling only, the water flux decreased significantly by about 21.7% and further decreased with an increasing Mn2+ concentration. However, Mn2+ has no direct effect on BSA. The effect degrees to which Mn2+ affected RO membrane fouling can be expressed as follows: HBS > SA > HA > BSA. The density functional theory (DFT) calculations also gave the same results. In modeling the reaction of the complexation of Mn2+ with the carboxyl group in these four types of organic matter, BSA has the highest energy (-55.7 kJ/mol), which predicts that BSA binding to Mn2+ is the most unstable compared to other organic matter. The BSA carboxylate group also has the largest bond length (2.538-2.574 Å) with Mn2+ and the weakest interaction force, which provides a theoretical basis for controlling RO membrane fouling exacerbated by Mn2+.

Soft X-ray induced color-tunable long afterglow phosphors Ca9-xTb(PO4)7:xMn2+ based on Mn2+ modulation and energy transfer

In this paper, X-ray induced color-tunable long afterglow luminescent material Ca9-xTb(PO4)7:xMn2+ was synthesized by high-temperature solid state reaction. The effects of Mn2+ doping concentration on the properties of the samples were studied by XRD, SEM, fluorescence and afterglow spectra. The results showed that there was a very efficient energy transfer between Tb3+and Mn2+under X-ray excitation, with a transfer efficiency of up to 94.6%, which also contributed to the tunable green-red emission. With the increase of Mn2+ concentration, the green afterglow emissions of Tb3+ mainly at 546.9 nm gradually decreased and even disappeared, while the red afterglow emissions of Mn2+ at 647.3 nm gradually increases due to excellent energy transfer. When the doping concentration of Mn2+ was 0.07, the red afterglow emissions were the strongest. Furthermore, even at low-dose radiation (3 mGy), the sample still possessed excellent afterglow performance, which can persist for more than 5 h. In addition, the samples also showed excellent photostimulated luminescence properties, which can be persist for many cycles by the irradiation of 980 nm laser. The thermoluminescence results revealed that the doping Mn2+ ions can not only enhance the trap concentrations obviously but also created new deep traps with trap depth of 0.864 eV, which thus resulted in better long afterglow luminescence and photostimulated luminescence properties of Ca9Tb(PO4)7:Mn2+.

The effect of Mn2+ additives on the capacity of aqueous Zn/δ-MnO2 batteries: Elucidating the Mn2+ concentration dependence of the irreversible transformation of δ-MnO2

Rechargeable aqueous Zn/MnO2 batteries receive extensive attention owing to the high capacity and safety. Pre-adding Mn2+ in electrolyte is widely adopted as an effective strategy to improve the electrochemical performance of Zn/MnO2 batteries. However, the reaction mechanism of MnO2 electrode during long cycles is still unclear with Mn2+ pre-added in electrolyte because of the complex reactions involved Mn2+. In this work, the reaction process of δ-MnO2 electrode with different concentration of Mn2+ pre-added in electrolyte is elucidated. The pre-addition of 0.1 M Mn2+ promotes the formation of vernadite on δ-MnO2 electrode and delivers extra capacity. Nevertheless, with the increasing Mn2+ concentration in electrolyte, electrochemical inactive ZnMn2O4 forms and the coverage of ZnMn2O4 nanoparticles on δ-MnO2 electrode hinders the electrodissolution of δ-MnO2 thus leading to the severe capacity fading. The different electrodeposition reactions with different concentration of Mn2+ pre-added in electrolyte cause the distinct irreversible transformation of δ-MnO2 into vernadite or ZnMn2O4 after long cycles. These findings shed new light on the reaction mechanism for δ-MnO2 electrode in aqueous zinc ion batteries.

The Effect of Mn2+ on the Microstructure and Mechanical Properties of ZrO2–Al2O3–SiO2 Ceramic Materials

The Effect of Mn2+ on the Microstructure and Mechanical Properties of ZrO2–Al2O3–SiO2 Ceramic Materials

Manganese Acts as an Environmental Inhibitor of Pseudomonas aeruginosa Biofilm Development by Inducing Dispersion and Modulating c-di-GMP and Exopolysaccharide Production via RbdA.

The opportunistic human pathogen Pseudomonas aeruginosa causes chronic infections that involve multicellular aggregates called biofilms. Biofilm formation is modulated by the host environment and the presence of cues and/or signals, likely affecting the pool of the bacterial second messenger cyclic diguanylate monophosphate (c-di-GMP). The manganese ion Mn2+ is a divalent metal cation that is essential for pathogenic bacterial survival and replication during the infection in a host organism. In this study, we investigated how Mn2+ alters P. aeruginosa biofilm formation via the regulation of c-di-GMP levels. Exposure to Mn2+ was found to temporally enhance attachment but impair subsequent biofilm development, apparent by reduced biofilm biomass accumulation and lack of microcolony formation due to the induction of dispersion. Moreover, exposure to Mn2+ coincided with reduced production of the exopolysaccharides Psl and Pel, decreased transcriptional abundance of pel and psl, and decreased levels of c-di-GMP. To determine whether the effect of Mn2+ was linked to the activation of phosphodiesterases (PDEs), we screened several PDE mutants for Mn2+-dependent phenotypes (attachment and polysaccharide production) as well as PDE activity. The screen revealed that the PDE RbdA is activated by Mn2+ and is responsible for Mn2+-dependent attachment, inhibition of Psl production, and dispersion. Taken together, our findings suggest Mn2+ is an environmental inhibitor of P. aeruginosa biofilm development that acts through the PDE RbdA to modulate c-di-GMP levels, thereby impeding polysaccharide production and biofilm formation but enhancing dispersion. IMPORTANCE While diverse environmental conditions such as the availability of metal ions have been shown to affect biofilm development, little is known about the mechanism. Here, we demonstrate that Mn2+ affects Pseudomonas aeruginosa biofilm development by stimulating phosphodiesterase RbdA activity to reduce the signaling molecule c-di-GMP levels, thereby hindering polysaccharide production and biofilm formation but enhancing dispersion. Our findings demonstrate that Mn2+ acts as an environmental inhibitor of P. aeruginosa biofilms, further suggesting manganese to be a promising new antibiofilm factor.

Solution NMR of Battery Electrolytes: Assessing and Mitigating Spectral Broadening Caused by Transition Metal Dissolution.

NMR spectroscopy is a powerful tool that is commonly used to assess the degradation of lithium-ion battery electrolyte solutions. However, dissolution of paramagnetic Ni2+ and Mn2+ ions from cathode materials may affect the NMR spectra of the electrolyte solution, with the unpaired electron spins in these paramagnetic solutes inducing rapid nuclear relaxation and spectral broadening (and often peak shifts). This work establishes how dissolved Ni2+ and Mn2+ in LiPF6 electrolyte solutions affect 1H, 19F, and 31P NMR spectra of pristine and degraded electrolyte solutions, including whether the peaks from degradation species are at risk of being lost and whether the spectral broadening can be mitigated. Mn2+ is shown to cause far greater peak broadening than Ni2+, with the effect of Mn2+ observable at just 10 μM. Generally, 19F peaks from PF6 - degradation species are most affected by the presence of the paramagnetic metals, followed by 31P and 1H peaks. Surprisingly, when NMR solvents are added to acquire the spectra, the degree of broadening is heavily solvent-dependent, following the trend of solvent donor number (increased broadening with lower solvent donicity). Severe spectral broadening is shown to occur whether Mn is introduced via the salt Mn(TFSI)2 or is dissolved from LiMn2O4. We show that the weak 19F and 31P peaks in spectra of electrolyte samples containing micromolar levels of dissolved Mn2+ are broadened to an extent that they are no longer visible, but this broadening can be minimized by diluting electrolyte samples with a suitably coordinating NMR solvent. Li3PO4 addition to the sample is also shown to return 19F and 31P spectral resolution by precipitating Mn2+ out of electrolyte samples, although this method consumes any HF in the electrolyte solution.

Biochemical characteristics of point mutated Capra hircus lysosome α-mannosidase.

Locoweeds, a type of poisonous weedare, are widely distributed throughout the world and have a significant impact on the development of herbivore animal husbandry. Swainsonine (SW), the main toxin in locoweeds, can competitively inhibit lysosomes α-mannosidase (LAM) in animal cells, resulting in α-mannosidosis. However, the specifics of the interaction between SW and LAM are still unclear. Here, we used molecular docking to predicte the interaction points between SW and LAM, built mutated lysosomes α-mannosidase (LAMM), and analyzed its biochemical properties changes in presumption points. The Trp at the 28th position and the Tyr at the 599th position of the LAM were interaction point candidates, and the above two amino acids in Capra hircus LAM (chLAM), were successfully mutated to glycine by constructing recombinant yeast GS115/PIC9K- LAMM. The results showed that the sensitivity of Capra hircus LAMM (chLAMM), to SW decreased significantly compared with wild-type LAM, the enzyme activity of LAM decreased approximately threefold, the optimum temperature of LAMM decreased from 55°C to 50°C, the optimum pH value increased from 4.5 to 5.0, and the effects of Mn2+, Fe3+, Al3+, Co2+, Cr3+, and ethylenediaminetetraacetic acid (EDTA) on LAM enzyme activity before and after point mutation changed significantly. These findings help us better understanding the molecular mechanism of the interaction mechanism between SW and chLAM, and provide new reference for solving locoweeds poisoning.

Manganese immunotherapy for treating osteosarcoma: Glycosylating 1V209 anchored MnO2 nanosheets prompt pro-inflammatory macrophage polarization

Current immunotherapy has not met the curative expectations in the treatment of osteosarcoma. As the most abundant immune cells in the tumor microenvironment (TME), macrophages are closely related to the progression of osteosarcoma. Recently, bivalent manganese ions (Mn2+) have been found to present great potential for immunotherapy in natural killer cells and dendritic cells. However, the effect of Mn2+ on macrophage polarization remains entirely unclear, especially in the TME. Toll-like receptor 7 (TLR7) agonists can initiate innate immune responses but are limited in clinical application for their hydrophobicity. Herein, we prepare BSA-templated MnO2 nanosheets (BMs) and conjugate 1V209, a small molecule TLR7 agonist, with a sugar group to improve hydrophilicity and immunostimulatory effects. Sugar-conjugated 1V209 (SV) is further anchored onto BMs to construct SV@BMs. In our study, SV@BMs can react with glutathione (GSH) to release Mn2+ and produce plenty of reactive oxygen species (ROS) via Mn2+-mediated Fenton-like reactions in macrophages. ROS generated by pro-inflammatory macrophages can induce apoptosis of tumor cells. Mn2+ and co-released SV together promote pro-inflammatory macrophage polarization, which may depend on the activation of the NF-κB signal pathway. In vivo, the application of SV@BMs significantly activates local and systematic immunity, eliminates tumor cells and reduces lung metastases.

Manganese suppresses the development of oral leukoplakia by activating the immune response.

Manganese ion (Mn2+ ) is reported to promote the antitumor immune response by activating the cGAS-STING pathway, but it is unknown whether Mn2+ can prevent the malignant transformation of precancerous lesions. The effects of Mn2+ in treating oral leukoplakia (OLK) were explored in this work. Peripheral blood Mn analysis of the patients was performed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). A coculture model of dendritic cells (DCs)/macrophages, CD8+ T cells, and dysplastic oral keratinocytes (DOKs) was employed to analyze the role and mechanism of Mn2+ in a simulated OLK immune microenvironment. Western blot, RT-PCR, flow cytometry, enzyme-linked immunosorbent assay (ELISA), and lactate dehydrogenase (LDH) assays were adopted to detect the mechanism of Mn2+ in this model. 4-nitroquinoline oxide (4NQO)-induced OLK mice were used to assess the role of Mn2+ in suppressing OLK progression, and a novel Mn2+ -loaded guanosine-tannic acid hydrogel (G-TA@Mn2+ hydrogel) was fabricated and evaluated for its advantages in OLK therapy. The content of Mn in patients' peripheral blood was negatively related to the progression of OLK. Mn2+ promoted the maturation and antigen presentation of DCs and macrophages and enhanced the activation of CD8+ T cells in the coculture model, resulting in effective killing of DOKs. Mechanistic analysis found that Mn2+ enhanced the anti-OLK immune response by activating the cGAS-STING pathway. Moreover, Mn2+ suppressed the development of 4NQO-induced carcinogenesis in the mouse model. In addition, the G-TA@Mn2+ hydrogel had better anti-OLK effects. Mn2+ enhanced the anti-OLK immune response by activating the cGAS-STING pathway, and the G-TA@Mn2+ hydrogel is a potential novel therapeutic approach for OLK treatment.

Effect of Mn2+/Zn2+/Fe3+ Oxy(Hydroxide) Nanoparticles Doping onto Mg-Al-LDH on the Phosphate Removal Capacity from Simulated Wastewater.

A parent Mg-Al-LDH was upgraded in its adsorption properties due to the incorporation of tri-metal species oxy(hydroxide) nanoparticles obtaining Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite for the phosphate recovery from simulated urban treated wastewater. The physicochemical properties of the synthesized Mn2+/Zn2+/Fe3+/Mg-Al-LDH make promising for real application without being environmentally harmful. The performance of Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was evaluated through batch adsorption assays. The support of iron, manganese, and zinc (oxy)hydroxide nanoparticles onto the parent Mg-Al-LDH structure was performed by precipitation, isomorphic substitution, and complexation reactions. The main improvement of the Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was the highest phosphate adsorption capacity (82.3 mg∙g−1) in comparison to the parent Mg-Al-LDH (65.3 mg∙g−1), in a broad range of concentrations and the effective phosphate adsorption at neutral pH (7.5) near to the real wastewater effluents conditions in comparison to the conventional limitations of other adsorbents. The effectiveness of Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was higher than the conventional metal LDHs materials synthesized in a single co-precipitation step. The phosphate adsorption onto Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was described to be governed by both physical and chemical interactions. The support of Mn2+/Zn2+/Fe3+ oxy(hydroxide) nanoparticles over the parent Mg-Al-LDH was a determinant for the improvement of the phosphate adsorption that was governed by complexation, hydrogen bonding, precipitation, and anion exchange. The intra-particular diffusion also described well the phosphate adsorption onto the Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite. Three specific stages of adsorption were determined during the phosphate immobilization with an initial fast rate, followed by the diffusion through the internal pores and the final equilibrium stage, reaching 80% of removal and the equilibrium within 1 h. The Mn2+/Zn2+/Fe3+/Mg-Al-LDH was strongly selective towards phosphate adsorption in presence of competing ions reducing the adsorption capacity at 20%. The Mn2+/Zn2+/Fe3+/Mg-Al-LDH has limited reusability, only 51% of the adsorbed phosphate could be recovered in the second cycle of the adsorption-desorption process. Around 14% of phosphate was loosely-bond to Mn2+/Zn2+/Fe3+/Mg-Al-LDH which brings the opportunity to be a new source of phosphorus. The use of eluted concentrates and the final disposal of the exhausted adsorbent for soil amendment applications can be an integral nutrient system (P, Mn, Zn, Fe) for agriculture purposes.

A single‐structured LuAG:Ce,Mn phosphor ceramics with high CRI for high‐power white LEDs

AbstractThe realization of high color rendering index (CRI) is still a great challenge for high‐power LEDs (hp‐LEDs), which is hindered by the phosphor converter. In this work, based on the strategy of Ce3+ and Mn2+ multi‐ion substitution, the single‐structured LuAG:Ce,Mn ceramics with high CRI were prepared via regulating the ratio of tri‐color (red, green, and blue) components. The effects of Mn2+‐Si4+ pairs doping content on the crystal structure, morphologies, and luminescence properties were investigated in detail. The red emission centered at 590 and 750 nm were effectively compensated by regulating Mn2+ occupancy sites, resulting in a significant improvement of CRI. Pure white light with general CRI Ra up to 91.0, special CRI R9 reaching 37.9 and LE as high as 85.07 lm/W was achieved, when the hp‐LEDs were constructed from related phosphor ceramic Ce02Mn7. These results suggest that the LuAG:Ce,Mn phosphor ceramics are highly promising color converters for hp‐LEDs application.