Synergistic enzymatic mechanism of lepidolite leaching enhanced by a mixture of Bacillus mucilaginosus and Bacillus circulans.

Numerous studies have demonstrated that the co-leaching of ores by different silicate bacteria significantly improves the performance of bioleaching systems. Nevertheless, the mechanism of different silicate bacteria synergistically or complementarily enhanced the leaching process of lithium-containing silicate remains unclear. This study discussed the leaching impact of the combined presence of two metabolically distinct silicate bacteria on lepidolite, with the aim of comprehending the synergistic effect resulting from the presence of Bacillus mucilaginosus and Bacillus circulans in the leaching process. The results indicated that the polysaccharides and proteins secreted by bacteria-containing functional groups such as -OH and -COOH, which played an important role in the complex decomposition of ores. Organic acids played the role of acid etching and complexation. Bacillus mucilaginosus and Bacillus circulans exhibited low individual leaching efficiency, primarily due to their weak organic acid secretion. Moreover, the prolific polysaccharide production by Bacillus mucilaginosus led to bacterial aggregation, diminishing contact capability with minerals. Bacillus circulans decomposed the excessive polysaccharides produced by Bacillus mucilaginosus through enzymatic hydrolysis in the co-bioleaching process, providing later nutrient supply for both strains. The symbiosis of the two strains enhanced the synthesis and metabolic capabilities of both strains, resulting in increased organic acid secretion. In addition, protein and humic acid production by Bacillus mucilaginosus intensified, collectively enhancing the leaching efficiency. These findings suggested that the primary metabolic products secreted by different bacterial strains in the leaching process differ. The improvement in bioleaching efficiency during co-leaching was attributed to their effective synergistic metabolism. This work contributes to the construction of an efficient engineering microbial community to improve the efficiency of silicate mineral leaching, and reveals the feasibility of microbial co-culture to improve bioleaching.

Research on the decomposition mechanisms of lithium silicate ores with different crystal structures by autotrophic and heterotrophic bacteria.

Ores serve as energy and nutrient sources for microorganisms. Through complex biochemical processes, microorganisms disrupt the surface structure of ores and release metal elements. However, there is limited research on the mechanisms by which bacteria with different nutritional modes act during the leaching process of different crystal structure ores. This study evaluated the leaching efficiency of two types of bacteria with different nutritional modes, heterotrophic bacterium Bacillus mucilaginosus (BM) and autotrophic bacterium Acidithiobacillus ferrooxidans (AF), on different crystal structure lithium silicate ores (chain spodumene, layered lepidolite and ring elbaite). The aim was to understand the behavioral differences and decomposition mechanisms of bacteria with different nutritional modes in the process of breaking down distorted crystal lattices of ores. The results revealed that heterotrophic bacterium BM primarily relied on passive processes such as bacterial adsorption, organic acid corrosion, and the complexation of small organic acids and large molecular polymers with metal ions. Autotrophic bacterium AF, in addition to exhibiting stronger passive processes such as organic acid corrosion and complexation, also utilized an active transfer process on the cell surface to oxidize Fe2+ in the ores for energy maintenance and intensified the destruction of ore lattices. As a result, strain AF exhibited a greater leaching effect on the ores compared to strain BM. Regarding the three crystal structure ores, their different stacking modes and proportions of elements led to significant differences in structural stability, with the leaching effect being highest for layered structure, followed by chain structure, and then ring structure. These findings indicate that bacteria with different nutritional modes exhibit distinct physiological behaviors related to their nutritional and energy requirements, ultimately resulting in different sequences and mechanisms of metal ion release from ores after lattice damage.

Advances and Prospects in the Treatment of Pancreatic Cancer.

Pancreatic cancer is a highly malignant and incurable disease, characterized by its aggressive nature and high fatality rate. The most common type is pancreatic ductal adenocarcinoma (PDAC), which has poor prognosis and high mortality rate. Current treatments for pancreatic cancer mainly encompass surgery, chemotherapy, radiotherapy, targeted therapy, and combination regimens. However, despite efforts to improve prognosis, and the 5-year survival rate for pancreatic cancer remains very low. Therefore, it's urgent to explore novel therapeutic approaches. With the rapid development of therapeutic strategies in recent years, new ideas have been provided for treating pancreatic cancer. This review expositions the advancements in nano drug delivery system, molecular targeted drugs, and photo-thermal treatment combined with nanotechnology for pancreatic cancer. It comprehensively analyzes the prospects of combined drug delivery strategies for treating pancreatic cancer, aiming at a deeper understanding of the existing drugs and therapeutic approaches, promoting the development of new therapeutic drugs, and attempting to enhance the therapeutic effect for patients with this disease.

Advances in aptamer-mediated targeted delivery system for cancer treatment.

Aptamers with high affinity and specificity for certain targets have rapidly become a novel class of targeted ligands applicated in drug delivery. Based on the excellent characteristics of aptamers, different aptamer-mediated drug delivery systems have been developed, including aptamer-drug conjugate (ApDC), aptamer-siRNA, and aptamer-functionalized nanoparticle systems for the effective treatment of cancer, which can reduce potential toxicity and improve therapeutic efficacy. In this review, we summarize the recent progress of aptamer-mediated delivery systems in cancer therapy, and discuss the application prospects and existing problems of innovative approaches based on aptamer therapy. Overall, this review aims to better understand the current aptamer-based targeted delivery applications through in-depth analysis to improve efficacy and develop new therapeutic methods which can ultimately improve treatment outcomes for cancer patients.

Self-induced suppression of collective neutrino oscillations in a supernova.

We investigate collective flavor oscillations of supernova neutrinos at late stages of the explosion. We first show that the frequently used single-angle (averaged coupling) approximation predicts oscillations close to, or perhaps even inside, the neutrinosphere, potentially invalidating the basic neutrino transport paradigm. Fortunately, we also find that the single-angle approximation breaks down in this regime; in the full multiangle calculation, the oscillations start safely outside the transport region. The new suppression effect is traced to the interplay between the dispersion in the neutrino-neutrino interactions and the vacuum oscillation term.

Flavor evolution of the neutronization neutrino burst from an O-Ne-Mg core-collapse supernova.

We present results of 3-neutrino flavor evolution simulations for the neutronization burst from an O-Ne-Mg core-collapse supernova. We find that nonlinear neutrino self-coupling engineers a single spectral feature of stepwise conversion in the inverted neutrino mass hierarchy case and in the normal mass hierarchy case, a superposition of two such features corresponding to the vacuum neutrino mass-squared differences associated with solar and atmospheric neutrino oscillations. These neutrino spectral features offer a unique potential probe of the conditions in the supernova environment and may allow us to distinguish between O-Ne-Mg and Fe core-collapse supernovae.

Neutrino mass hierarchy and stepwise spectral swapping of supernova neutrino flavors.

We examine a phenomenon recently predicted by numerical simulations of supernova neutrino flavor evolution: the swapping of supernova nu(e) and nu(mu,tau) energy spectra below (above) energy E(C) for the normal (inverted) neutrino mass hierarchy. We present the results of large-scale numerical calculations which show that in the normal neutrino mass hierarchy case, E(C) decreases as the assumed effective 2x2 vacuum nu(e)<==>nu(mu,tau) mixing angle (approximately theta13) is decreased. In contrast, these calculations indicate that E(C) is essentially independent of the vacuum mixing angle in the inverted neutrino mass hierarchy case. With a good neutrino signal from a future galactic supernova, the above results could be used to determine the neutrino mass hierarchy even if theta13 is too small to be measured by terrestrial neutrino oscillation experiments.

Coherent development of neutrino flavor in the supernova environment.

We calculate coherent neutrino and antineutrino flavor transformation in the supernova environment, for the first time including self-consistent coupling of intersecting neutrino and antineutrino trajectories. For neutrino mass-squared difference /deltam2/ = 3 x 10(-3) eV2 we find that in the normal (inverted) mass hierarchy the more tangentially-propagating (radially-propagating) neutrinos and antineutrinos can initiate collective, simultaneous medium-enhanced flavor conversion of these particles across broad ranges of energy and propagation direction. Accompanying alterations in neutrino and antineutrino energy spectra and fluxes could affect supernova nucleosynthesis and the expected neutrino signal.