Sodium–selenium (Na–Se) and potassium–selenium (K–Se) batteries have emerged as promising energy storage systems with high energy density and low cost. However, major issues such as huge Se volume ...changes, polyselenide shuttling, and low Se loading need to be overcome. Although many strategies have been developed to resolve these issues, the relationship between the carbon host pore structure and electrochemical performance of Se has not been studied extensively. Here, the effect of the carbon host pore structure on the electrochemical performance of Na–Se and K–Se batteries is investigated. N, S-co-doped hierarchically porous carbon microspheres with different pore structures that can incorporate a large amount of amorphous Se (∼60 wt %) are synthesized by spray pyrolysis and subsequent chemical activation at different temperatures. By optimizing the amount of micropore volume and micropore-to-mesopore ratio, high reversible capacity and cycling stability are achieved for the Se cathode. The optimized cathode delivers a reversible capacity of 445 mA h g–1 after 400 cycles at 0.5C for Na–Se batteries and 436 mA h g–1 after 120 cycles at 0.2C for K–Se batteries. This study marks the importance of developing conductive carbon matrices with delicately designed pore structures for advanced alkali metal–chalcogen battery systems.
Pathogenesis hallmarks for tuberculosis (TB) are the Mycobacterium tuberculosis (Mtb) escape from phagolysosomal destruction and limited drug delivery into infected cells. Several nanomaterials can ...be entrapped in lysosomes, but the development of functional nanomaterials to promote phagolysosomal Mtb clearance remains a big challenge. Here, we report on the bactericidal effects of selenium nanoparticles (Se NPs) against Mtb and further introduce a novel nanomaterial‐assisted anti‐TB strategy manipulating Ison@Man‐Se NPs for synergistic drug‐induced and phagolysosomal destruction of Mtb. Ison@Man‐Se NPs preferentially entered macrophages and accumulated in lysosomes releasing Isoniazid. Surprisingly, Ison@Man‐Se/Man‐Se NPs further promoted the fusion of Mtb into lysosomes for synergistic lysosomal and Isoniazid destruction of Mtb. Concurrently, Ison@Man‐Se/Man‐Se NPs also induced autophagy sequestration of Mtb, evolving into lysosome‐associated autophagosomal Mtb degradation linked to ROS‐mitochondrial and PI3K/Akt/mTOR signaling pathways. This novel nanomaterial‐assisted anti‐TB strategy manipulating antimicrobial immunity and Mtb clearance may potentially serve in more effective therapeutics against TB and drug‐resistant TB.
Destructive duo: The bactericidal effects of selenium nanoparticles (NPs) were combined with the delivery of the drug Isoniazid via the mannose‐decorated nanomaterial Ison@Man‐Se NPs for the synergistic drug‐induced and phagolysosomal destruction of Mycobacterium tuberculosis (Mtb).
Background and aims
Ageing is an important factor for controlling selenium bioavailability and toxicity in soil.
Methods
The ageing processes of selenite and selenate in two soils were systematically ...investigated by adopting diffusive gradients in thin film technique (DGT) and sequential extraction.
Results
Soluble Se was the main fraction (29.3%–61.7%) for selenate-treated soils, and which decreased significantly (52.5% for chestnut soil and 44.2% for black soil) and transformed to less labile fractions with ageing. By contrast, exchangeable Se fraction was the main fraction in selenite-treated soils, which decreased by 38%–71.8% with ageing. The DGT measurement (
C
DGT
) of selenate treatment was 1.8–96.7 times higher than that of selenite treatment. Dynamic analysis showed that shorter response time
T
c
(44 s) and higher desorption rate constant
k
−1
(≥ 1.5E-3 s
−1
) were observed in selenite-treated chestnut soil than black soil, which coincided with the higher Se contents in pak choi planted in chestnut soil than black soil. The opposite result was found for selenate, demonstrating that Se bioavailability was affected by soil properties and Se species.
Conclusions
This study demonstrated that DGT can describe the changes of Se bioavailability caused by ageing and predict Se uptake by pak choi roots in selenite- or selenate-aged soils.
Fertilization with Se improves forage organic Se concentration, but comparisons with other forms of Se supplementation in feeding lactating dairy cows are scarce. Our objective was to compare the ...effect of Se-enriched forages to dietary sources of inorganic and organic Se. Digestibility, retention, and balance were assessed by measuring Se concentrations in feces, urine, milk, and blood. The resulting effect on antioxidant status and lactation performance of dairy cows was also determined. High-Se silages 1.72 mg of Se/kg of dry matter (DM) were produced following a spring application of 2.5 kg/ha of Selcote Ultra, whereas low-Se silages (0.05 mg of Se/kg of DM) were produced in the Se-unfertilized portion of the same fields. After a 77±17 d period of Se depletion, 33 late-lactation primiparous Holstein cows were blocked and randomly assigned for 43 d to 1 of 4 experimental total mixed rations fed for ad libitum intake in an unbalanced randomized block design. Treatments consisted of 4 diets: control with low-Se silages, without Se supplement (0.12±0.04 mg of Se/kg of DM); ISe with low-Se silages and inorganic Se (0.80±0.14 mg of Se/kg of DM); YSe with low-Se silages and organic Se from yeast (0.70±0.11 mg of Se/kg of DM); and FSe with high-Se silages, without Se supplement (0.79±0.14 mg of Se/kg of DM). Organic Se, either as YSe or FSe, was more available and more effective to increase blood and milk Se concentrations than ISe. Moreover, FSe was more available than YSe, as cows fed FSe excreted 16 and 22% less Se (as percentage of intake) in feces and urine, respectively, had higher Se apparent absorption (17%), retention (37%), and balance (45%), and had greater concentration of Se in serum (16%) and milk (11%) than cows fed YSe. Antioxidant status (whole blood and plasma glutathione peroxidase, and milk thioredoxin reductase and malondialdehyde) was not affected by treatments. Dry matter intake, yield of actual, energy-corrected, and fat-corrected milk, as well as milk fat and lactose concentrations, were not affected by the dietary treatments. Cows fed ISe had lower milk protein concentration (3.44%) than cows fed YSe (3.58%) or FSe (3.51%). Cows fed Se-supplemented diets had a lower milk somatic cell count than cows fed the control diet. Results from the current study showed that the production of Se-enriched forages is an effective method to supplement dairy cows in Se as it was more available than YSe, and did not alter antioxidant status and performances of lactating dairy cows.
Although the issue has been of much concern and has subsequently been controlled for years, the environmental risk of excess selenium (Se) in farmlands still has not been eliminated in Se-toxicity ...areas. Different types of farmland utilization can change Se behavior in soil. Thus, located field monitoring and surveys of various farmland soils in and around typical Se-toxicity areas spanning eight years were conducted in the tillage layer and deeper soils. The source of new Se contamination in farmlands was traced along the irrigation and natural waterway. This research indicated that 22 % of paddy fields increased to Se-toxicity in surface soil led by irrigation with high-Se river water. Selenate is the dominant Se species in rivers (90 %) originating from geological background areas with high Se. Both soil organic matter (SOM) and amorphous iron content played important roles in the fixation of input Se. Thus, available Se was increased by more than twofold in paddy fields. The release of residual Se and eventual bounding by organic matter is commonly observed, thus suggesting that stable soil Se availability seems sustainable for a long time. This study is the first report in China that shows how new soil Se-toxicity farmland is caused by high-Se water irrigation. This research warns that external attention should be paid to the selection of irrigation water in high-Se geological background areas to avoid new Se contamination.
Display omitted
•Irrigation led to new Se-toxicity paddy fields in and around Se-toxicity area.•Se from high-Se geological background areas will migrate with streams.•Soil organic matter and amorphous iron played important roles during Se fixation.•It's the first report in China of new farmland Se contamination caused by irrigation.
Coronavirus disease 2019 (COVID-19) is a global pandemic causing one of the biggest challenges for critical care medicine. Mortality from COVID-19 is much greater in elderly men, many of whom succumb ...to acute respiratory distress syndrome (ARDS) triggered by the viral infection. Because there is no specific antiviral treatment against COVID-19, new strategies are urgently needed. Selenium is an essential trace element with antioxidant and immunomodulatory effects. Poor nutritional status increases the pathogenicity of viruses and low selenium in particular can be a determinant of viral virulence. In the past decade, selenium pharmaconutrition studies have demonstrated some reduction in overall mortality, including how reduced incidence of ventilator-associated pneumonia and infectious complications such as ARDS in the critically ill. Consequently, we postulate that intravenous selenium therapy, could be part of the therapeutic fight against COVID-19 in intensive care unit patients with ARDS and that outcomes could be affected by age, sex, and body weight. Our working hypothesis addresses the question: Could high-dose selenite pharmaconutrition, as an early pharmacologic intervention, be effective at reducing the incidence and the progression from type 1 respiratory failure (non-ARDS) to severe ARDS, multiorgan failure, and new infectious complications in patients with COVID-19 patients?
•Poor selenium status is associated to viral virulence.•Selenium as selenite may be able to inhibit the entrance of severe acute respiratory syndrome coronavirus 2 in host cells, impeding its ability to infect healthy individuals.•We propose that high-dose selenite pharmaconutrition may be effective at reducing the incidence and progression of multiorgan failure, and new infections in patients with coronavirus disease 2019 (COVID-19).•We postulate that clinical outcomes could be affected by age, sex, and body weight.
Increasing evidences suggest that nanoscale zero-valent iron (nZVI) is an effective agent for treatment and removal of selenium from water. For example, 1.3 mM selenite was quickly removed from water ...within 3 min with 5 g/L nZVI. In this work, reaction mechanisms of selenite Se(IV) in a single core–shell structured nanoscale zero-valent iron (nZVI) particle were studied with the method of spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) integrated with X-ray energy dispersive spectroscopy (XEDS). This method was utilized to visualize solid phase translocation and transformation of Se(IV) such as diffusion, reduction, deposition and the effect of surface defects in a single nanoparticle. Se(IV) was reduced to Se(-II) and Se(0), which then formed a 0.5 nm layer of selenium at the iron oxide-Fe(0) interface at a depth of 6 nm from the surface. The results provided near atomic-resolution proof on the intraparticle diffusion-reduction of Se(IV) induced by nZVI. The STEM mapping also discovered that defects on the surface layer accelerate the diffusion of selenium and increase the capacity of nZVI for selenium sequestration.
Mechanisms of selenium (IV) sequestration in nanoscale zero-valent iron (nZVI). Display omitted
•Se(IV) can be separated from water, reduced and encapsulated by nZVI.•Near atomic-resolution imaging on the Se diffusion-reduction in nZVI is obtained.•Defects on the nZVI nanoparticles apparently can enhance selenium removal.•Reduction and sequestration fully explain rapid and large capacity Se(IV) removal.•STEM-XEDS is usable for visualizing solid phase reaction at near atomic resolution.
Selenium (Se) has recently been demonstrated to reduce inorganic mercury (IHg) accumulation in rice plants, while its mechanism is far from clear. Here, we aimed at exploring the potential effects of ...Se application routes (soil or foliar application with Se), speciation (selenite and selenate), and doses on IHg-Se antagonistic interactions in soil-rice systems. Results of our pot experiments indicated that soil application but not foliar application could evidently reduce tissue IHg concentrations (root: 0–48%, straw: 15–58%, and brown rice: 26–74%), although both application routes resulted in comparable Se accumulation in aboveground tissues. Meanwhile, IHg distribution in root generally increased with amended Se doses in soil, suggesting antagonistic interactions between IHg and Se in root. These results provided initial evidence that IHg-Se interactions in the rhizosphere (i.e., soil or rice root), instead of those in the aboveground tissues, could probably be more responsible for the reduced IHg bioaccumulation following Se application. Furthermore, Se dose rather than Se speciation was found to be more important in controlling IHg accumulation in rice. Our findings regarding the importance of IHg-Se interactions in the rhizosphere, together with the systematic investigation of key factors affecting IHg-Se antagonism and IHg bioaccumulation, advance our understanding of Hg dynamics in soil-rice systems.
•Soil application with Se could reduce inorganic mercury (IHg) accumulation in rice.•Foliar application with Se could increase Se but not IHg accumulation in rice.•IHg-Se antagonism in soil-rice systems depends on Se doses and Se application routes.•Se speciation (selenite and selenate) may play a minor role in IHg-Se antagonism.•IHg-Se interactions in soil could be important in explaining IHg-Se antagonism.
Selenium (Se) as one of the essential trace elements for human plays an important role in the oxidation reduction system. But the high toxicity of Se limits its application. In this case, the element ...Se with zero oxidation state (Se
) has captured our attention because of its low toxicity and excellent bioavailability. However, Se
is very unstable and easily changes into the inactive form. By now many efforts have been done to protect its stability. And this work was conducted to explore the antioxidant capacities of the stable Se
nanoparticles (SeNPs) stabilized using chitosan (CS) with different molecular weights (Mws) (CS-SeNPs).
The different Mws CS-SeNPs could form uniform sphere particles with a size of about 103 nm after 30 days. The antioxidant tests of the DPPH, ABTS, and lipid peroxide models showed that these CS-SeNPs could scavenge free radicals at different levels. And the 1 month old SeNPs held the higher ABTS scavenging ability that the value could reach up to 87.45 ± 7.63% and 89.44 ± 5.03% of CS(l)-SeNPs and CS(h)-SeNPs, respectively. In the cell test using BABLC-3T3 or Caco-2, the production of the intracellular reactive oxygen species (ROS) could be inhibited in a Se concentration-dependent manner. The topical or oral administration of CS-SeNPs, particularly the Se nanoparticles stabilized with low molecular weight CS, CS(l)-SeNPs, and treated with a 30-day storage process, could efficiently protect glutathione peroxidase (GPx) activity and prevent the lipofusin formation induced by UV-radiation or D-galactose in mice, respectively. Such effects were more evident in viscera than in skin. The acute toxicity of CS(l)-SeNPs was tenfold lower than that of H
SeO
.
Our work could demonstrate the CS-SeNPs hold a lower toxicity and a 30-day storage process could enhance the antioxidant capacities. All CS-SeNPs could penetrate the tissues and perform their antioxidant effects, especially the CS(l)-SeNPs in mice models. What's more, the antioxidant capacities of CS-SeNPs were more evident in viscera than in skin.
Cadmium (Cd) as a ubiquitous toxic heavy metal is reported to affect the nervous system. Selenium (Se) has been shown to have antagonistic effects against heavy metal toxicity. In addition, it shows ...potential antioxidant and anti-inflammatory properties. Thus, the purpose of this study was to determine the possible mechanism of brain injury after high Cd exposure and the mitigation of Nano-selenium (Nano-Se) against Cd-induced brain injury. In this study, the Cd-treated group showed a decrease in the number of neurons in brain tissue, swelling of the endoplasmic reticulum and mitochondria, and the formation of autophagosomes. Nano-Se intervention restored Cd-caused alterations in neuronal morphology, endoplasmic reticulum, and mitochondrial structure, thereby reducing neuronal damage. Furthermore, we found that some differentially expressed genes were involved in cell junction and molecular functions. Subsequently, we selected eleven (11) related differentially expressed genes for verification. The qRT-PCR results revealed the same trend of results as determined by RNA-Seq. Our findings also showed that Nano-Se supplementation alleviated Cx43 phosphorylation induced by Cd exposure. Based on immunofluorescence colocalization it was demonstrated that higher expression of GFAP and lower expressions of Cx43 were restored by Nano-Se supplementation. In conclusion, the data presented in this study establish a direct association between the phosphorylation of Cx43 and the occurrence of autophagy and neuroinflammation. However, it is noteworthy that the introduction of Nano-Se supplementation has been observed to mitigate these alterations. These results elucidate the relieving effect of Nano-Se on Cd exposure-induced brain injury.
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