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Blood-brain barrier (BBB) disruption is a prominent pathophysiological mechanism in stroke. Transplantation of mesenchymal stem cells (MSCs) preserves BBB integrity following ischemic stroke. Fibroblast growth factor 21 (FGF21) has been shown to be a potent neuroprotective agent that reduces neuroinflammation and protects against BBB leakage. In this study, we assessed the effects of transplantation of MSCs overexpressing FGF21 (MSCs-FGF21) on ischemia-induced neurological deficits and BBB breakdown. MSCs-FGF21 was injected into the rat brain via the intracerebroventricular route 24 h after middle cerebral artery occlusion (MCAO) surgery. The behavioral performance was assessed using modified neurological severity scores and Y-maze tests. BBB disruption was measured using Evans blue staining, IgG extravasation, and brain water content. The levels of tight junction proteins, aquaporin 4, and neuroinflammatory markers were analyzed by western blotting and immunohistochemistry. The activity of matrix metalloproteinase-9 (MMP-9) was determined using gelatin zymography. At day-5 after MCAO surgery, intraventricular injection of MSCs-FGF21 was found to significantly mitigate the neurological deficits and BBB disruption. The MCAO-induced loss of tight junction proteins, including ZO-1, occludin, and claudin-5, and upregulation of the edema inducer, aquaporin 4, were also remarkably inhibited. In addition, brain infarct volume, pro-inflammatory protein expression, and MMP-9 activation were effectively suppressed. These MCAO-induced changes were only marginally improved by treatment with MSCs-mCherry, which did not overexpress FGF21. Overexpression of FGF21 dramatically improved the therapeutic efficacy of MSCs in treating ischemic stroke. Given its multiple benefits and long therapeutic window, MSC-FGF21 therapy may be a promising treatment strategy for ischemic stroke. [ABSTRACT FROM AUTHOR]

Maleic acid (MA) induces renal tubular cell dysfunction directed to acute kidney injury (AKI). AKI is an increasing global health burden due to its association with mortality and morbidity. However, targeted therapy for AKI is lacking. Previously, we determined mitochondrial-associated proteins are MA-induced AKI affinity proteins. We hypothesized that mitochondrial dysfunction in tubular epithelial cells plays a critical role in AKI. In vivo and in vitro systems have been used to test this hypothesis. For the in vivo model, C57BL/6 mice were intraperitoneally injected with 400 mg/kg body weight MA. For the in vitro model, HK-2 human proximal tubular epithelial cells were treated with 2 mM or 5 mM MA for 24 h. AKI can be induced by administration of MA. In the mice injected with MA, the levels of blood urea nitrogen (BUN) and creatinine in the sera were significantly increased (p < 0.005). From the pathological analysis, MA-induced AKI aggravated renal tubular injuries, increased kidney injury molecule-1 (KIM-1) expression and caused renal tubular cell apoptosis. At the cellular level, mitochondrial dysfunction was found with increasing mitochondrial reactive oxygen species (ROS) (p < 0.001), uncoupled mitochondrial respiration with decreasing electron transfer system activity (p < 0.001), and decreasing ATP production (p < 0.05). Under transmission electron microscope (TEM) examination, the cristae formation of mitochondria was defective in MA-induced AKI. To unveil the potential target in mitochondria, gene expression analysis revealed a significantly lower level of ATPase6 (p < 0.001). Renal mitochondrial protein levels of ATP subunits 5A1 and 5C1 (p < 0.05) were significantly decreased, as confirmed by protein analysis. Our study demonstrated that dysfunction of mitochondria resulting from altered expression of ATP synthase in renal tubular cells is associated with MA-induced AKI. This finding provides a potential novel target to develop new strategies for better prevention and treatment of MA-induced AKI. [ABSTRACT FROM AUTHOR]

Zeolites are aluminosilicate minerals with multiple channels and cages. They are widely used in industry; further, owing to its increasing demand, the hydrothermal synthesis of zeolites from natural minerals/rocks has attracted great attention. This study aims to discuss the crystal growth mechanisms of zeolites from pumice. Pumice is a widely available porous volcanic glass (mainly consisting of 65–75% SiO2 and 9–20% Al2O3) that can be used in the fabrication of zeolites. In this study, zeolite was formed from pumice via a hydrothermal method with varying alkaline concentrations, reaction times and temperatures, and addition of NaCl. Zeolite Na-P1 was synthesized under conditions of 0.1 or 0.5 M at 150 °C. The feldspar phase (albite) initially occurred, followed by the zeolite phase (zeolite Na-P1). Phillipsite was an unstable intermediate product during this synthesis process. Based on these results, we suggest that the phase transformation sequence follows the order of albite, phillipsite, and zeolite Na-P1. Moreover, it can be speculated that an increase in cation concentration can induce a rapid occurrence of the zeolite phase (zeolite Na-P1). Raman spectrometry analyses provided insights into the formation mechanism of zeolite structures, indicating differences related to the number of sodium ions. Both zeolite Na-P1 and phillipsite are composed of four- and eight-membered rings, and the former is mainly grown with four-membered rings as the main structure. This study provides a low-cost and simple synthetic method for producing zeolite Na-P1 and phillipsite, which can be used as indicator minerals for marine/lake facies and in environmental treatment. [ABSTRACT FROM AUTHOR]

Determination of hematite contributions to sedimentary magnetizations is an important but difficult task in quantitative environmental studies. The poorly crystalline and fine-grained nature of hematite nanoparticles makes quantification of their concentrations in natural environments challenging using mineralogical and spectroscopic methods, while the weak magnetization of hematite and often significant superparamagnetic nanoparticle concentrations make quantification difficult using magnetic remanence measurements. We demonstrate here that much-used magnetic parameters, such as the S-ratio and 'hard' isothermal remanent magnetization (HIRM), tend to significantly underestimate relative and absolute hematite contents, respectively. Unmixing of isothermal remanent magnetization (IRM) acquisition curves is among the more suitable approaches for defining magnetic mineral contributions, although it has under-appreciated uncertainties that limit hematite quantification. Diffuse reflectance spectroscopy and other methods can enable relative hematite and goethite content quantification under some conditions. Combined use of magnetic, mineralogical, and spectroscopic approaches provides valuable cross-checks on estimated hematite contents; such an integrated approach is recommended here. Further work is also needed to rise to the challenge of developing improved methods for hematite quantification. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of Cr(VI) adsorption onto nano-magnetite was examined by batch experiments, and the Cr(VI) adsorption mechanism was investigated using synchrotron-based X-ray absorption spectroscopy. Magnetite nanoparticles with a mean diameter of 10 nm were synthesized using an inexpensive and simple co-precipitation method. It shows a saturation magnetization of 54.3 emu/g, which can be recovered with an external magnetic field. The adsorption data fitted the Langmuir adsorption isotherm well, implying a monolayer adsorption behavior of Cr(VI) onto nano-magnetite. X-ray absorption spectroscopy results indicate that the adsorption mechanism involves electron transfer between Fe(II) in nano-magnetite (Fe2+OFe3+2O3) and Cr(VI) to transform into Cr(III), which may exist as an Fe(III)-Cr(III) mixed solid phase. Moreover, the Cr(III)/Cr(VI) ratio in the final products can be determined by the characteristic pre-edge peak area of Cr(VI) in the Cr K-edge spectrum. These findings suggest that nano-magnetite is effective for Cr(VI) removal from wastewater because it can transform highly poisonous Cr(VI) species into nontoxic Cr(III) compounds, which are highly insoluble and immobile under environmental conditions. [ABSTRACT FROM AUTHOR]

Water pollution, including the generation of wastewater, is becoming an increasingly serious global issue. In this study, ilmenite (FeTiO3) nano-photocatalysts were synthesized via a simple sol-gel method to determine their applicability to wastewater remediation. Methylene blue was photocatalytically decomposed by visible light in the presence of nano-ilmenite, and batch experiments were performed to study the adsorption characteristic. The results reveal that nano-ilmenite exhibits good photocatalytic activity under visible-light illumination (rate constant, 0.029 min−1) and possesses a high adsorption capacity (22.2 mg/g) for copper ions. These results indicate that nano-ilmenite is a good photocatalyst. The photocatalytic activity combined with its high copper ion adsorption activity renders it a suitable material for wastewater treatment. [ABSTRACT FROM AUTHOR]

In traditional learning, students passively absorb the materials provided by their teachers or textbooks. Thus, their learning autonomy is insufficient, and this affects learning motivation. Students find it difficult to absorb the knowledge taught in a classroom and apply it to real life. We combined situated learning and learning through drama to help realize students’ autonomy and ownership. A situational learning system using a comic play was devised to help students learn through scriptwriting in groups. When learning through drama, the visual aids on stage can provide students with a sense of immersion, which strengthens their knowledge application. This method was applied during English-language courses of fifth-grade students at an elementary school in Taiwan. Students’ questionnaire responses demonstrated that using this system helped their autonomous learning. The students’ sense of identification with their own work and their learning impressions were substantially improved. Examination results of the students from the experimental group were significantly higher from those from a control group taught using traditional teaching methods. [ABSTRACT FROM AUTHOR]

Iron sulphide minerals have been used in industrial applications for many years, and more recently there has been increasing interest in the use of iron sulphide nanomaterials because of their useful properties and low cost. Previous studies have mainly focused on the synthesis of iron sulphides, but their phase transition and micro-magnetic properties are still unclear. In this study, iron sulphide minerals were synthesized via a hydrothermal method, and their phase transition mechanisms and magnetic properties were investigated. Ex situ and in situ X-ray diffraction results of the iron–sulphur system under hydrothermal conditions suggested that the transformation sequence followed the order of mackinawite (FeS) → greigite (Fe3S4) → smythite (Fe9S11) → pyrrhotite (Fe9S10). Pure greigite and pyrrhotite were obtained during the synthesis processes, after 1 h at 120 and 160 °C, respectively. Greigite showed a granular morphology with particle diameters around 30 nm, and pyrrhotite comprised stacked hexagonal sheets with thousands of nanometers in width. Pyrrhotite showed anti-ferromagnetic behaviour; however, it did not saturate up to magnetic field of 7 T. Greigite was ferrimagnetic, with a high saturation magnetization of 62.7 Am2 kg−1 and coercive magnetic field of 27.6 mT. Magnetic force microscope measurements of greigite revealed that its magnetic structure belonged to a spin-canted single domain. Overall, this study provides new information on the phase transition mechanism, related reaction formulas, and magnetic properties of iron sulphides, and it emphasizes the important role played by temperature/time in phase transitions. [ABSTRACT FROM AUTHOR]

Air exposure causes extreme stress in fish. Most fish die within minutes when exposed to air; however, the common carp Cyprinus carpio can survive in air for several hours. To understand the hematological response following prolonged air exposure and its association with zinc, common carp were exposed to air for 4 h and allowed to recover in an aquarium for 140 h at 25 °C. Hematological analysis and microscopic examination of the blood cells revealed that during the recovery period, the total RBC count remained relatively constant, but the RBC composition changed greatly. After 20 h of recovery, 35 % of the mature RBCs had degraded and were replaced by immature RBCs. Among the RBCs that were renewed, 15 % were likely derived from the release of stored RBCs from the spleen immediately after air exposure, and the other 20 % appeared to be generated via erythropoiesis. An increase in the rate of erythropoiesis in the common carp was triggered and facilitated by zinc in the head kidney. The renewed RBCs had significantly higher osmotic resistance than RBCs obtained from fish at rest. These results suggest that the replacement of one-third of mature RBCs with immature RBCs can increase fish tolerance to stress. [ABSTRACT FROM AUTHOR]

To separate the connective tissue cells expressing the 43-kDa zinc-binding protein from the common carp, mucosa of the digestive tract of the fish was removed by scraping with a glass slide, and the de-mucosa tissue was digested with a collagenase type IV solution. The cells collected from the collagenase-treated suspension were rather homogeneous, and more than 90% of the cells were round with a diameter of approximately 6 μm. Significant quantities of the 43 kDa zinc-binding protein were shown to be present on the cell surface of the approximately 6-μm cells. The mean zinc concentration in the cells was found to be 2.21 μg zinc/106 cells, which is approximately 20–30 times higher than that found in the other three fish species (grass carp, silver carp, tilapia) studied. The present work may provide a basis for the culture of these cells. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of Cr(VI) adsorption onto nano-magnetite was examined by batch experiments, and the Cr(VI) adsorption mechanism was investigated using synchrotron-based X-ray absorption spectroscopy. [ABSTRACT FROM AUTHOR]