Decrease In Na Research Articles

Apatite as a Probe into the Nature and Origin of Hydrothermal Fluids Responsible for U Leaching in the Lujing Granite-Related U Deposits, South China

Abstract Hydrothermal fluids have been suggested to be capable of leaching U and other elements (e.g., rare earth elements; REEs) from U-fertile granites to form granite-related U deposits. However, the nature and origin of the hydrothermal fluid responsible for transporting these elements are poorly constrained. Apatite accommodates both U and REEs, and its composition can be modified by hydrothermal fluids with certain compositions. This study investigated in situ chemical and Sr-Nd isotope compositions of primary apatite in altered wall granites from the Lujing U deposits in the Zhuguang batholiths. Large-scale alterations of apatite occurred during the hematitization stage. Uranium was extensively leached out of the apatite, and its total REE concentrations were decreased from as high as 12,667 ppm to a few hundred ppm during the alteration, whereas REE-bearing mineral inclusions were absent in altered apatites. The release of U and REEs was associated with decrease of Na, Mn, and Fe and increase of Ca, Cl, and Eu anomalies in altered regions of apatite. According to apatite compositional variations, the fluid that induced hematitization was oxidizing, rich in Ca and Cl, but poor in Na. The elevated Cl in the fluid is crucial for mobilizing both U and REEs, whereas PO43− can also be a major ligand for U6+ transport given the massive dissolution of apatite during the leaching process. Altered regions of apatite contain high radiogenic strontium, implying assimilation of the fluid by clastic sediments in the adjacent red-bed basins sourced from the Precambrian crystalline basement rocks. The oxidizing, Ca- and Cl-rich, but Na- and F-poor fluid that induces hematitization shows significant potential in leaching U and REEs from the wall granite and providing ore-forming materials for U mineralization.

Synergistic Impact of Melatonin and Putrescine Interaction in Mitigating Salinity Stress in Snap Bean Seedlings: Reduction of Oxidative Damage and Inhibition of Polyamine Catabolism

While the individual influences of melatonin (MT) and polyamines (PAs) have been widely studied under various abiotic stresses, little is known about their interaction under salinity stress. In the present study, salt stress applied by 50 mM of sodium chloride (NaCl) on snap bean seedlings has been supplemented with 20 μM of MT and/or 100 μM of putrescine (Put) (individually and in combination). The results indicated that under salinity stress, the combination of MT + Put achieved the highest significant increase in shoot fresh and dry weight, chlorophyll (Chl a), Chl a + b, carotenoids, total soluble sugars, proline, K, Ca, and cell membrane stability index (CMSI), as well as catalase (CAT) and peroxidase (POX) activities. This improvement was associated with an obvious decrease in Na, Na/K ratio, and oxidative damage as indicated by reducing leaf contents of methylglyoxal (MG), hydrogen peroxide (H2O2), and the rate of lipid peroxidation (malondialdehyde; MDA). Moreover, the combination of MT + Put demonstrated a significant decrease in the activities of diamine oxidase (DAO) and polyamine oxidase (PAO) leading to the reduction of the rate of polyamine oxidation. Meanwhile, MT applied individually gave the highest significant increase in leaf relative water content (RWC), Chl b, superoxide dismutase (SOD), and ascorbate peroxidase (APX). Conclusively, the combination treatment of MT + Put could decrease the degradation of polyamines and enhance tolerance to salinity stress in snap bean seedlings.

Mg2+ extrusion activated by hydrogen peroxide in rat ventricular myocytes.

To investigate the effect of reactive oxygen species (ROS) on intracellular-free Mg2+ concentration ([Mg2+]i), we measured [Mg2+]i in rat ventricular myocytes using a fluorescent indicator, mag-fura-2. The treatment of hydrogen peroxide (H2O2, 500 μM) for 5 min decreased [Mg2+]i from 1.02 ± 0.08 (mean ±SD, n = 7) to 0.75 ± 0.18 mM (p = 0.018, by Wilcoxon signed-rank test) in ∼9 min (including the 5-min treatment and subsequent washout). [Mg2+]i was continuously decreased in ∼ 20 min, and then recovered to the basal level (∼1.0 mM) gradually in the Ca2+-free Tyrode's solution. The half maximal effective concentration of H2O2 on the Mg2+- decrease was estimated to be between 400 and 425 μM. The rate of decrease in [Mg2+]i by H2O2 in the Ca2+-free Tyrode's solution (−0.61± 0.42 μM/s, n = 36) was not significantly different from that obtained in the absence of extracellular Na+ or Mg2+. The addition of 1 mM Ca2+ extracellularly slowed the rate of Mg2+- decrease, on average, by ∼60% (p = 0.002, by Mann-Whitney U-test). The H2O2-induced Mg2+ decrease in Na+-free (substituted with N-methyl-d-glucamine) /Ca2+-free Tyrode's solution was inhibited by 200 μM imipramine, a known inhibitor of Na+/Mg2+ exchange. Rat hearts were perfused with the Ca2+-free Tyrode's solution containing 500 μM H2O2 for 5 min on the Langendorff apparatus. The Mg2+-concentration of the cardiac perfusate was significantly increased after H2O2 administration, suggesting that the H2O2-induced Mg2+-decrease was caused by Mg2+- extrusion. Pyocyanin, a generator of reactive oxygen species also reduced [Mg2+]i. The Mg2+-decrease by pyocyanin was inhibited by a pretreatment of n-acetyl cysteine, an anti-oxidant. In conclusion, it is suggested ROS disrupt intracellular Mg2+ homeostasis, and that the existence of a Na+-independent Mg2+- extrusion system activated by H2O2 in cardiomyocytes.

Voltage-gated sodium channels gene expression in Burning Mouth Syndrome: a case-control study

Burning mouth syndrome (BMS) is a condition characterized by painful symptoms of the oral mucosa, despite the absence of any clinical signs. Its etiology is unknown, and there is still no effective treatment to date. Current evidence has shown neuropathic impairment in BMS patients. Neuropathic pain can be related to the dysfunction of voltage-gated sodium channels, considering that these receptors regulate the induction of action potentials in nociceptive neurons. This study evaluated the gene expression of voltage-gated sodium channels Na v 1.7, Na v 1.8 and Na v 1.9 in these patients. The gene expressions of these channels were assessed by real time RT-PCR analysis of fresh-frozen tongue biopsies in a case-control study composed of 12 patients with BMS, and 5 healthy control patients, proportionally matched by sex and age, and analyzed using the 2^(-Delta Delta CT) method. There was no statistically significant difference between the analyzed groups, despite the increase in Na v 1.7 (fold-change = 3.13, p = 0.52) and decrease in Na v 1.9 (fold-change = 0.45, p = 0.36) gene expression in the BMS group. The Na v 1.8 gene was not expressed in any of the samples analyzed. Although the gene expression in the voltage-gated sodium channels in BMS under study seems to be comparable with that of the normal oral mucosa, the functionality of these channels in BMS has not yet been identified, thus suggesting that further research is needed to better understand these voltage-gated sodium channels.

Lycium barbarum polysaccharide protects cardiomyocytes from hypoxia/reoxygenation injury via activation of SIRT3/CypD signaling.

Myocardial ischemia-reperfusion is a common pathological feature of many heart and vascular diseases, but the molecular mechanism of this process is still unclear, and there is no effective way to protect cardiomyocytes. The aim of this study was to examine the effects and underlying molecular mechanisms of Lycium barbarum polysaccharide (LBP) on myocardial ischemia-reperfusion injury in cardiomyocytes. The cardiomyocyte cell line H9c2 were used to establish an in vitro hypoxia/reoxygenation (H/R) model. After treatment with LBP and/or the SIRT3 inhibitor 3-TYP, cell morphology was observed under the light microscopy. The Cell Counting Kit (CCK)-8 and 5-ethynyl-2'-deoxyuridine (EdU) assay were used to detect cell proliferation, and flow cytometry was performed to assess cell apoptosis. The lysine (166)-acetylation of CypD1 was determined by co-immunoprecipitation assay. Enzyme-linked immunosorbent assay (ELISA) was used to determine the lactate dehydrogenase (LDH) level in the culture medium. Na+-K+-ATPase activity, Ca2+-ATPase activity, and nitric oxide (NO) levels were measured. LBP alleviated cell damage and upregulated STIR3 expression in a dose-dependent manner. Upregulated SIRT3 expression and suppressed acetylation of CypD were also observed in H/R-induced H9c2 cells treated with LBP. Indeed, LBP remarkably reversed the inhibition of proliferation and cell apoptosis in H/R-induced H9c2 cells by activating SIRT3/CypD signaling. Blockade of SIRT3 with SIRT3 inhibitor (3-TYP) inhibited the protective effect of LBP on H9c2 cells. LBP markedly alleviated the H/R-induced increase of LDH release, and the decrease of Na+-K+-ATPase activity, Ca2+-ATPase activity, and NO levels. Inhibition of SIRT3 restored the protective effects of LBP. LPB induced deacetylation of CypD by upregulating SIRT3, thereby protecting mitochondrial function and relieving H/R-induced injury in cardiomyocytes.

Effect of pressure quenching on the structures and properties of borosilicate glasses: Insights from molecular dynamics simulations

Combining thermal and pressure effect represents a novel approach to modify glass properties. However, the microscopic structural origin of these property modifications is complex and far from fully understood, especially in multicomponent glasses with mixed glass formers. In this paper, we have utilized classical molecular dynamics simulations with a set of composition dependent potentials to investigate pressure-quenching effect on sodium borosilicate glasses. Processes including hot compression, cold compression and subsequent annealing on the structures and properties are investigated and compared. It was found that applying pressure up to 10 GPa at the glass transition temperature led to permanent densifications and a dramatic increase of elastic moduli by 90%, while thermal annealing reversed the increase and applying pressure at ambient temperture did not increase the modulus. The main structural change of the hot compressed sample is the increase of four-fold coordinated boron while silicon remains four-fold coordinated. The sodium environment shows an increase of coordination number and a decrease of Na O and Na Na bond distances. Medium range structure is also changed with an increase of 8-membered rings. These results provide atomistic insights of the pressure quench effect on borosilicate glasses. • Compared cold compression, compression near T g and annealing effect on glass structure and properties • Up to 90% increase of elastic moduli due to hot compression while cold compression led to little change of elastic properties • Hot compression increases [4] B and Na coordination while a decrease of Na O bond distance • Medium range structure change observed in ring size distribution • Combing thermal and pressure effect a novel way to modify glass properties

Evaluation of T-cell aging-related immune phenotypes in the context of biological aging and multimorbidity in the Health and Retirement Study

BackgroundCellular changes in adaptive immune system accompany the process of aging and contribute to an aging-related immune phenotype (ARIP) characterized by decrease in naïve T-cells (TN) and increase in memory T-cells (TM). A population-representative marker of ARIP and its associations with biological aging and age-related chronic conditions have not been studied previously.MethodsWe developed two ARIP indicators based on well understood age-related changes in T cell distribution: TN/(TCM (Central Memory) + TEM (Effector Memory) + TEFF (Effector)) (referred as TN/TM) in CD4 + and CD8 + T-cells. We compared them with existing ARIP measures including CD4/CD8 ratio and CD8 + TN cells by evaluating associations with chronological age and the Klemera Doubal measure of biological age (measured in years) using linear regression, multimorbidity using multinomial logistic regression and two-year mortality using logistic regression.ResultsCD8 + TN and CD8 + TN/TM had the strongest inverse association with chronological age (beta estimates: -3.41 and -3.61 respectively; p-value < 0.0001) after adjustment for sex, race/ethnicity and CMV status. CD4 + TN/TM and CD4 + TN had the strongest inverse association with biological age (β = -0.23; p = 0.003 and β = -0.24; p = 0.004 respectively) after adjustment for age, sex, race/ethnicity and CMV serostatus. CD4/CD8 ratio was not associated with chronological age or biological age. CD4 + TN/TM and CD4 + TN was inversely associated with multimorbidity. For CD4 + TN/TM, people with 2 chronic conditions had an odds ratio of for 0.74 (95%CI: 0.63–0.86 p = 0.0003) compared to those without any chronic conditions while those with 3 chronic conditions had an odds ratio of 0.75 (95% CI: 0.63–0.90; p = 0.003) after adjustment for age, sex, race/ethnicity, CMV serostatus, smoking, and BMI. The results for the CD4 + TN subset were very similar to the associations seen with the CD4 + TN/TM. CD4 + TN/TM and CD4 + TN were both associated with two-year mortality (OR = 0.80 (95% CI: 0.67–0.95; p = 0.01) and 0.81 (0.70–0.94; p = 0.01), respectively).ConclusionCD4 + TN/TM and CD4 + TN had a stronger association with biological age, age-related morbidity and mortality compared to other ARIP measures. Future longitudinal studies are needed to evaluate the utility of the CD4 + subsets in predicting the risk of aging-related outcomes.

Acute Neuromuscular and Hormonal Responses to Power, Strength, and Hypertrophic Protocols and Training Background

This study investigated how two slightly different athlete groups would differ in acute neuromuscular and endocrine responses to specific resistance exercise loadings and recovery compared to untrained participants. Power athletes (PA, n = 8), strength athletes (SA, n = 8) and non-athletes (NA, n = 7) performed power (PL, 7 × 6 × 50% of 1RM), maximal strength (MSL, 7 × 3 × 3RM), and hypertrophic (HL, 5 × 10 × 10RM) loadings in Smith-machine back-squat. Neuromuscular performance, serum testosterone, growth hormone, and cortisol concentrations, and blood lactate (BL) were measured before (Pre), at Mid and after (Post) loading, and after recovery for 24 and 48 h. All loadings led to acute decreases in neuromuscular performance and elevations in hormone concentrations and BL. During PL, a significant group × time interactions occurred in maximal isometric force [F(4, 40) = 4.189, p = 0.006, = 0.295] indicating a greater decrease in PA compared to SA from Pre to Mid (p < 0.05), and in countermovement jump height [F(4, 40) = 2.895, p = 0.034, = 0.224] indicating a greater decrease in NA compared to SA from Pre to Mid (p < 0.05). During HL, growth hormone was higher in Mid and Post in SA compared to NA (p < 0.05). No significant interactions were found during recovery. The differences during PL and HL suggest that the training background may enhance acute responses during the present loadings, whereas it seemed to have a limited effect on the recovery.

Storage Lesions after Irradiation

Background and Objectives: Saline adenine glucose mannitol (SAGM) with citrate phosphate dextrose (CPD) or CPD adenine (CPDA) are two common red cell preservatives used in our country. This study analyzed and compared serial biochemical changes on different days of storage in irradiated packed red blood cells stored in CPDA and SAGM solutions. The aim of this study was to see if these changes are influenced by or different, if any, in these two storage solutions. Patients and Methods: Ninety units of RBCs were randomly chosen, with 45 units each collected in CPDA and SAGM, respectively. Nine units each were irradiated by gamma irradiator using cobalt 60 (BI 2000) on days 1, 7, 14, and 21 of their storage, respectively. Nine units were not irradiated and used as controls. All the units were weekly assessed for their plasma levels of potassium, sodium, glucose, lactate dehydrogenase (LDH), and lactate by Clinical Chemistry Auto-analyzer, Beckman Coulter AU680. The values were documented and analyzed by SPSS. Results: Baseline values on day 1 for potassium, lactate, and LDH were similar between SAGM- and CPDA-stored blood bags. Glucose and sodium levels were slightly higher in SAGM bags compared to CPDA. Postirradiation, the changes (increase in K+, Lactate, LDH and decrease in Na+, glucose) were higher in CPDA bags than SAGM bags, and the difference in this trend was not significantly different from that seen in nonirradiated blood bags stored in these two preservative solutions. Conclusion: Storage lesions (biochemical parameters) after irradiation were severe, but paralleled that observed in nonirradiated bags. The storage solution, either SAGM or CPDA, made no difference to these changes.

Effect of arbuscular myccorhizal fungi on soil properties, mineral nutrition and antioxidant enzymes of olive plants under treated wastewater irrigation

The present study aimed to determine the impact of arbuscular mycorrhizal fungi (AMF) on soil and young olive plants irrigated for one year with saline treated wastewater (TWW). One-year-old olive plants were inoculated with different AMF: (i) Glomus deserticola; (ii) Gigaspora margarita and (iii) combination of G. deserticola and G. margarita. Changes were observed in the soil chemical characteristics, in particular a significant increase in the electrical conductivity and an accumulation of Na+ and Cl−. Consequently, compared to the control treatment, the Na+ and Cl− contents of young olive plants irrigated with TWW increased by 12 and 133% in the leaves and by 98 and 106% in the roots, respectively. Moreover, an increase in the antioxidant enzyme activities, malondialdehyde and H2O2 contents, and electrolyte leakage rate was observed. Interestingly, roots and leaves of olive plants inoculated with AMF and irrigated with TWW showed a lower Na+ and Cl−content, and a higher macro- and micro-nutrient content, compared to uninoculated plants. The decrease of Na+ and Cl− contents in olive plants inoculated with both G. deserticola and G. margarita was about 24 and 43% in the leaves, and about 30 and 39% in the roots, respectively. Furthermore, the AMF symbiosis enhanced the antioxidant enzymes activities (CAT and APX) and reduced the malondialdehyde and H2O2 contents.

Bacillus atrophaeus WZYH01 and Planococcus soli WZYH02 Improve Salt Tolerance of Maize (Zea mays L.) in Saline Soil.

With the increasing shortage of land resources and people’s attention to the ecological environment, the application of microbial fertilizer with natural soil microorganisms as the main component has attracted increasing attention in saline agriculture. In this study, two salt-tolerant strains, YL07 (Bacillus atrophaeus) and YL10 (Planococcus soli), were isolated from maize (Zea mays L.) rhizosphere soil with a saturated conductivity (ECe) of 6.13 dS/m and pH of 8.32 (Xinjiang, China). The effects of B. atrophaeus WZYH01 (YL07) and Planococcus soli WZYH02 (YL10) on the growth and development of maize (Zea mays L.) under salt stress (ECe = 5.9 dS/m) were further studied. The results showed that compared with uninoculation, inoculation with B. atrophaeus WZYH01 and Planococcus soli WZYH02 significantly improved maize growth performance, biomass yield, and antioxidant levels under salt stress, and the effect of Planococcus soli WZYH02 was more prominent than the effect of B. atrophaeus WZYH01. Moreover, inoculation with B. atrophaeus WZYH01 and Planococcus soli WZYH02 protected maize from salt stress by regulating plant hormone [IAA and abscisic acid (ABA)] levels and increasing nutrient acquisition. In addition, the tested strains were most efficient for maize growth and health, increasing the content of K+ accompanied by an effective decrease in Na+ in maize tissues. The transcription levels of salt tolerance genes (ZMNHX1, ZMNHX2, ZMHKT, ZMWRKY58, and ZMDREB2A) in inoculated maize were also dramatically higher than the transcription levels of the specified salt tolerance genes in uninoculated maize. In conclusion, B. atrophaeus WZYH01 and Planococcus soli WZYH02 can alleviate the harmful effects of salt stress on crop growth, thereby promoting sustainable agricultural development.

Digestibility of Meat Mineral and Proteins from Broilers Fed with Graded Levels of Chlorella vulgaris.

The incorporation of sustainable protein sources in animal feeding is a growing trend. So far, no study has investigated in vitro digestion of meat, from broilers fed microalgae, in a human model. This research aimed to evaluate the effect of incorporating Chlorella vulgaris in the broilers diet on human protein digestibility, and mineral bioaccessibility. The study used 240 male Ross 308 broilers randomly allocated to groups fed a control diet or a diet where soybean meal was replaced with 10% (CV10%), 15% (CV15%), or 20% (CV15%) of C. vulgaris for 40 days. The microalga supplementation increased the protein and lowered the fat content in the muscle. Results on the percentages of amino acids highlighted that arginine and threonine proportions increased and lysine and cysteine proportions decreased with microalga inclusion. CV15% and CV20% meat had higher amount of K, Ca, Mg, P, and Fe in raw breasts, improving the nutrient composition of the meat. Cooking caused a decrease in Na and K and an increase in other minerals. CV20% had higher bioaccessibility of K, Ca, Mg, P, and Mg, compared to the control. Replacing soybean meal in broiler feed with higher concentrations of C. vugaris could improve the digestibility of meat protein and minerals.

The Alteration of Giglio Island Granite: Relevance to the Conservation of Monumental Architecture

The research examines the alteration phenomena of Giglio island granite, a rock quarried by Romans from the 3rd century, used for columns in the Italian peninsula and later reemployed in many Christian religious buildings. The study has shown that already in the bedrock there are small percentages of clay minerals. Starting from this condition, the alteration develops by an increase in porosity, which in turn favours the establishment of a slight hydrolysis of the silicates with a decrease in Na, Ca, and K, in accordance with the sericitisation process. The alteration proceeds with a further increase in porosity, apparently not related to a real loss of cohesion, which, however, occurs shortly after, highlighting the necessity of a continuous monitoring of the state of conservation of the material in the architectural heritage.

Selective removal of Na+ by NaTi2(PO4)3-MWCNT composite hollow-fiber membrane electrode in capacitive deionization

In this study, NaTi2(PO4)3 (NTP) nanoparticles were incorporated into a carbon nanotube hollow-fiber (CHF) electrode for the selective removal of Na+ during the capacitive deionization (CDI) of salty water. Due to the Na+-selective electro-sorption of NTP nanoparticles, NTP-CHF achieved 1.5 ~2 times higher Na+ adsorption capacity than that of CHF only electrodes at a range of 1.7 mM~17.1 mM (100 mg L−1~1000 mg L−1) NaCl solution. Moreover NTP-CHF sustained the Na+ adsorption capacity even at the presence of Ca2+ ions, whereas the dramatic decrease in Na+ removal was observed in CHF with an increase of Ca2+ concentration. As the result, NTP-CHF can retain 52% of the initial Na+ removal capacity after three times of capture and release cycles at the presence of Ca2+, while CHF showed <10% of the initial Na+ removal capacity due to the irreversible adsorption of Ca2+ ions onto the MWCNT surface. Thus, the incorporation of NTP into the conductive carbon nanomaterial network can greatly improve both the adsorption capacity and selectivity of Na+ compared to the conventional carbon-based electrode during the CDI of salty water containing multivalent cations such as Ca2+.

Hormetic Effect of 3-Bromopyruvate on Age-Induced Alterations in Erythrocyte Membrane Transporters and Oxidative Biomarkers in Rats.

3-Bromopyruvate (3-BP) is a glycolytic inhibitor and a potential calorie restriction mimic that shows a variety of beneficial effects in several aging model systems. A chronic low dose of 3-BP was given to male Wistar rats for 4 weeks. The effect of 3-BP on age-dependent alteration on the activities of various transporters/exchangers and redox biomarkers (protein carbonyl [PC], sialic acid [SA], sulfhydryl group [-SH], intracellular calcium ion [Ca2+]i, and osmotic fragility) was studied. In aged rats, 3-BP treatment increases the membrane-bound activities of Na+/K+-ATPase (NKA) and Ca2+-ATPase (PMCA), along with levels of -SH and SA. It also exerts a concomitant decrease in Na+/H+ exchanger (NHE) activity and the levels of [Ca2+]i, PC, and osmotic fragility in aged groups. 3-BP can be considered as a potential antiaging agent that induces a hormetic effect leading to amelioration of age-dependent impairment of membrane-bound ATPases and alterations in the redox biomarker level.

Potential mechanisms of Na+/K+-ATPase attenuation by heat and pesticides co-exposure in goldfish: role of cellular apoptosis, oxidative/nitrative stress, and antioxidants in gills.

In this study, we examined the dose-dependent effects of an environmentally relevant pesticide cocktail (metalachlor, linuron, isoproturon, tebucanazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) and temperature change (22 vs. 32°C for 4-week exposure) on Na+/K+-ATPase, 3-nitrotyrosine protein (NTP), dinitrophenyl protein (DNP), catalase (CAT), and superoxide dismutase (SOD) expressions in gills of goldfish (Carassius auratus). Histopathological analysis showed widespread damage to gill in elevated temperature (32°C) and pesticide co-exposure groups, including fusion of secondary lamellae, club-shaped primary lamellae, rupture of epithelial layer, loss of normal architecture, and hemorrhaging. Immunohistochemical and qRT-PCR analyses showed significant decreases in Na+/K+-ATPase protein and mRNA expressions in gills exposed to higher temperature and pesticides; however, combined exposure to heat and pesticides significantly increases NTP, DNP, CAT, and SOD expressions. In situ TUNEL assay revealed elevated levels of apoptotic cells in response to combined exposure. Collectively, our results suggest the combined effects of heat and pesticide stress cause cellular damage, upregulate oxidative/nitrative stress biomarkers, and increase apoptotic cells, downregulate Na+/K+-ATPase expression in gills. This provides new evidence for oxidant/antioxidant-dependent mechanisms for downregulation of Na+/K+-ATPase expression in gills during combined exposure.

Developmental disorders caused by cefixime in the otic vesicles of zebrafish embryos or larvae

To explore the developmental toxicity of cefixime (CE) in the developmental disorder and toxicity mechanism of CE on otic vesicles, zebrafish embryos were used as an animal model. The results showed that CE increased mortality in a dose-dependent manner and decreased the hatching rate of zebrafish larva at 96 hpf. Interestingly, CE significantly reduced the area of the saccule and utricle, as well as the area of otic vesicles in zebrafish larvae (p < 0.001). Fibroblast growth factor 8a (Fgf8a) inhibitors and bone morphogenetic protein (BMP) inhibitors caused similar morphological changes. CE decreased the lateral hair cells of zebrafish larvae in a dose-dependent manner. Furthermore, CE caused the downregulation of cartilage and bone-related genes and Na+/K+-ATPase-related genes of zebrafish larvae at 72 hpf and 120 hpf according to RT-qPCR. A comparison with the control group revealed that 100 μg/mL CE also caused a decrease in Na+/K+-ATPase activity (p < 0.01). In addition, antibody staining verified that CE inhibited the expression of Na+/K+-ATPase in the otic vesicles and the nephridium of zebrafish larvae. The data obtained in this study suggested that CE has significant ototoxicity during embryonic development of zebrafish, which is closely related to Na+/K+-ATPase and the regulation of the Fgf8a/BMP signaling pathways. The effects and toxicity of CE on ear development in other animal models need to be further explored.

How Grain Boundaries and Interfacial Electrostatic Interactions Modulate Water Desalination via Nanoporous Hexagonal Boron Nitride.

To fulfill the increasing demand for drinking water, researchers are currently exploring nanoporous two-dimensional materials, such as hexagonal boron nitride (hBN), as potential desalination membranes. A prominent, yet unsolved challenge is to understand how such membranes will perform in the presence of defects or surface charge in the membrane material. In this work, we study the effect of grain boundaries (GBs) and interfacial electrostatic interactions on the desalination performance of bicrystalline nanoporous hBN using classical molecular dynamics simulations supported by quantum-mechanical density functional theory (DFT) calculations. We investigate three different nanoporous bicrystalline hBN configurations, with symmetric tilt GBs having misorientation angles of 13.2, 21.8, and 32.2°. Using lattice dynamics calculations, we find that grain boundaries alter the areas and shapes of nanopores in bicrystalline hBN, as compared to the nanopores in monocrystalline hBN. We observe that, although bicrystalline nanoporous hBN with a misorientation angle of 13.2° shows an improved water flow rate by ∼30%, it demonstrates reduced Na+ ion rejection by ∼6%, as compared to monocrystalline hBN. We also uncover the role of the nanopore shape in water desalination, finding that more elongated pores with smaller sizes (in 21.8- and 32.2°-misoriented bicrystalline hBN) can match water permeation through less elongated pores of slightly larger sizes, with a concomitant ∼3-4% decrease in Na+ rejection. Simulations also predict that the water flow rate is significantly affected by interfacial electrostatic interactions. Indeed, the water flow rate is the highest when altered partial charges on B and N atoms were determined using DFT calculations, as compared to when no partial charges or bulk partial charges (i.e., charged hBN) were considered. Overall, our work on water/ion transport through nanopores in bicrystalline hBN indicates that the presence of GBs and surface charge can lead, respectively, to a decrease in the ion rejection and water permeation performance of hBN membranes.

Implications of Major and Trace Element Migration in Altered Granites for Hydrothermal Alteration and Granite-Related Uranium Mineralization in the Sanjiu Ore Field, South China

The recently discovered Sanjiu ore field (SJOF) is a granite-related uranium ore field located in the middle of Zhuguangshan (South China). The relationship between hydrothermal alteration of granite and uranium mineralization in the SJOF is crucial yet understudied. In this study, the major- and trace-element contents of granite samples (fresh granite, altered granite, and tectonites) with different uranium contents were analyzed by using X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma–mass spectrometry (ICP–MS). The analytical results show a relative increase in Si, S, Ca, Pb, Mo, and Sb content in altered granites and tectonites, relative to fresh granites. During the mineralization stage, the increase of the aforementioned elements is related to various hydrothermal alterations (e.g., silicification, carbonation, sulfation, etc.) and newly formed minerals (e.g., microfine crystalline quartz veins; calcite agglomerates or fine veins; and metal sulfides, such as pyrite). There is a concomitant relative decrease in Na, K, Al, Fe, Mg, and other elemental contents that may be due to mineralogical alteration processes, such as biotite to chlorite, feldspar-group minerals to clay minerals, and redox of Fe-bearing minerals. The LREE/HREE ratio in altered granites decreases significantly with the increase in uranium content, suggesting that a low LREE/HREE ratio may be a prospecting indicator. The normalized trace-element patterns of mineralized granite (ore) and the relatively high U content of fresh granite imply that granitic rocks may be the primary uranium source in the SJOF. The uranium mineralization is mainly concentrated in the redox zone that occurs at a depth of 100−300 m. The redox zone is characterized by the most developed hydrothermal alterations and enrichment of trace elements, including W, Mo, Sb, Li, and the HREE.

Effect of curcumin nanoparticles on streptozotocin-induced male Wistar rat model of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease that afflicts millions of people all over the world. Intracerebroventricular (ICV) injection of a sub-diabetogenic dose of streptozotocin (STZ) was established as an experimental animal model of AD. The present study was conducted to evaluate the efficacy of curcumin nanoparticles (CNs) against the behavioral, neurochemical and histopathological alterations induced by ICV-STZ. The animals were divided into: control animals, the animal model of AD that received a single bilateral ICV microinjection of STZ, and the animals protected by a daily oral administration of CNs for 6days before the ICV-STZ injection. The animals of all groups were subjected to surgical operation on the 7th day of administration. Then the administration of distilled water or CNs was continued for 8days. The ICV-STZ microinjection produced cognitive impairment as evident from the behavioral Morris water maze (MWM) test and induced oxidative stress in the cortex and hippocampus as indicated by the significant increases in lipid peroxidation and nitric oxide (NO) levels and the significant decrease in reduced glutathione (GSH) levels. It also produced a significant increase in acetylcholinesterase (AChE) and tumor necrosis-alpha (TNF-ɑ) and a significant decrease in Na+,K + -ATPase. In addition, a significant increase in amino acid neurotransmitters occurred in the hippocampus, whereas a significant decrease was obtained in the cortex of STZ-induced AD rats. CNs ameliorated the behavioral, immunohistochemical and most of the neurochemical alterations induced by STZ in the hippocampus and cortex. It may be concluded that CNs might be considered as a promising therapeutic agent for the treatment of AD.