Desmoplastic small round cell tumor of the kidney: a case report and discussion.

A 13-year-old boy was admitted to the hospital with 1-month history of neck pain and a 2-week history of bilateral hip joint pain accompanied by low fever. Positron emission tomography-computed tomography (PET-CT) revealed the presence of a malignant tumor in the left kidney with metastases to the left renal hilum, retroperitoneum, para-aortic lymph nodes, and multiple bone sites throughout the body. Given that the patient's left kidney capsule was intact and the boundary with surrounding tissues was clear, left nephrectomy was performed. Postoperative pathological diagnosis showed desmoplastic small round cell tumor (DSRCT) of the left kidney. CAV-VIP alternating chemotherapy was given 20 days after the first stage surgery. After the end of the 6th cycle, the patient underwent surgery again. The tumor in front of the aorta and postcava, the greater omentum, the retroperitoneal lymph nodes and the hepatic hilum lymph nodes, and the visible tumors in the abdomen were removed. CAV-VIP alternating chemotherapy was continued after the second stage surgery. At the end of the 4th cycle of post operation chemotherapy, radiotherapy was started. An abdominal CT scan conducted 11 months after second-stage surgery did not reveal any recurrence of abdominal tumors; however bone metastases persisted. The patient is currently receiving oral targeted therapy with anlotinib while ongoing follow-up continues.

Preparing a novel baicalin-loaded microemulsion-based gel for transdermal delivery and testing its anti-gout effect.

We previously demonstrated that baicalin had efficacy against gouty arthritis (GA) by oral administration. In this paper, a novel baicalin-loaded microemulsion-based gel (B-MEG) was prepared and assessed for the transdermal delivery of baicalin against GA. The preparation method and transdermal capability of B-MEG was screened and optimized using the central composite design, Franz diffusion cell experiments, and the split-split plot design. Skin irritation tests were performed in guinea pigs. The anti-gout effects were evaluated using mice. The optimized B-MEG comprised of 50 % pH 7.4 phosphate buffered saline, 4.48 % ethyl oleate, 31.64 % tween 80, 13.88 % glycerin, 2 % borneol, 0.5 % clove oil and 0.5 % xanthan gum, with a baicalin content of (10.42 ± 0.08) mg/g and particle size of (15.71 ± 0.41) nm. After 12 h, the cumulative amount of baicalin permeated from B-MEG was (672.14 ± 44.11) µg·cm-2. No significant skin irritation was observed following B-MEG application. Compared to the model group, B-MEG groups significantly decreased the rate of auricular swelling (P < 0.01) and number of twists observed in mice (P < 0.01); and also reduced the rate of paw swelling (P < 0.01) and inflammatory cell infiltration in a mouse model of GA. In conclusion, B-MEG represents a promising transdermal carrier for baicalin delivery and can be used as a potential therapy for GA.

Preparation of modified chitosan-based nano-TiO2-nisin composite packaging film and preservation mechanism applied to chilled pork.

Here, we developed a nano-TiO2-nisin-modified chitosan composite packaging film and investigated its properties and antibacterial activity, as well as its effect on chilled pork preservation time. The results indicated that the preservation time of chilled pork coated with a nano-TiO2-nisin-modified chitosan film (including 0.7 g/L nano-TiO2, irradiated with ultraviolet light for 40 min, and dried for 6 h) followed by modified atmosphere packaging (50% CO2 + 50% N2) increased from 7 to 20 days at 4 °C. Both nano-TiO2 and nisin enhanced the mechanical strength of the chitosan film, and nisin promoted nano-TiO2 dispersion and compatibility in chitosan. Treatment with 0.4 g/L nano-TiO2 for 60 min considerably inhibited spoilage bacteria, particularly Acinetobacter johnnii XBB1 (A. johnnii XBB1). As nano-TiO2 concentration and photocatalytic time increased, K+, Ca2+, and Mg2+ leakage in A. johnnii XBB1 increased but Na+/K+-ATPase and Ca2+/Mg2+-ATPase activities decreased. In A. johnnii XBB1, TiO2 significantly downregulated the expression of putrefaction-related genes such as cysM and inhibited cell self-regulation and membrane wall system repair. Therefore, our nano-TiO2-nisin-modified chitosan film could extend the shelf life without the addition of any chemical preservatives, demonstrating great potential for application in food preservation.

S defect-rich MoS2 aerogel with hierarchical porous structure: Efficient photocatalysis and convenient reuse for removal of organic dyes.

To avoid the difficulty of separating solids from liquids when reusing powder photocatalysts, 3D stereoscopic photocatalysts were constructed. In this study, three-dimensional S defect-rich MoS2 hierarchical aerogel was prepared by chemical cross-linking of functional ultrathin 2D MoS2. Its phase, micro-morphology and structure were characterized, and it was used in the study of photocatalytic degradation of organic pollutants. Of the samples tested, MS@CA-3 (i.e., defect-rich 3D MoS2 aerogel with a loading of 30 mg of defect-rich MoS2) exhibited the best photocatalytic activity due to its suitable load, good light transmission, and a degradation rate of up to 91.0% after 3 h. In addition, MS@CA-3 aerogel offers high recyclability and structural stability, and the degradation rate of the organic pollutant methylene blue decreases only 9.8% after more than ten cycles of photocatalytic degradation. It combines the high catalytic performance of S defect-rich 2D MoS2 and the convenient reusability of hierarchical porous aerogel. This study provides valuable data and a reference for the practical promotion and application of photocatalytic technology in the field of environmental remediation.

Causes of recurrence of paediatric inguinal hernia after single-port laparoscopic closure.

PURPOSE: This paper explores the causes of paediatric inguinal hernia (PIH) recurrence after single-port laparoscopic percutaneous extraperitoneal closure (SPLPEC). METHOD: From January 2015 to December 2020, the clinical data of 3480 children with PIHs who underwent SPLPEC were retrospectively reviewed, including 644 children who underwent SPLPEC with a homemade single-hook hernia needle from January 2015 to December 2016 and 2836 children who underwent the SPLPEC with a double-hook hernia needle and hydrodissection from January 2017 to December 2020. There were 39 recurrences (including communicating hydrocele) during the 2-5 years of follow-up. The findings of redo-laparoscopy were recorded and correlated with the revised video of the first operation to analyse the causes of recurrence. RESULT: Thirty-three males and 6 females experienced recurrence, and 8 patients had a unilateral communicating hydrocele. The median time to recurrence was 7.1 months (0-38). There were 20 cases (3.11%) in the single-hook group and 19 cases (0.67%) in the double-hook group. Based on laparoscopic findings, recurrence most probably resulted from multiple factors, including uneven tension of the ligation (10 cases), missing part of the peritoneum (14 cases), loose ligation (8 cases), broken knot (5 cases), and knot reaction (2 cases). All children who underwent repeat SPLPEC were cured by double ligations or reinforcement with medial umbilical ligament. CONCLUSION: The main cause of recurrence is improper ligation. Tension-free and complete PIH ligation are critical to the success of surgery, which requires avoiding the peritoneum skip area and the subcutaneous and muscular tissues. Redo-laparoscopic surgery was suitable for the treatment of recurrent inguinal hernia (RIH). For giant hernias, direct ligation of the internal ring incorporating the medial umbilical ligament (DIRIM) may be needed.

Arsenic triggered nano-sized uranyl arsenate precipitation on the surface of Kocuria rosea.

Arsenic (As) and uranium (U) frequently occur together naturally and, in consequence, transform into cocontaminants at sites of uranium mining and processing, yet the simultaneous interaction process of arsenic and uranium has not been well documented. In the present contribution, the influence of arsenate on the removal and reduction of uranyl by the indigenous microorganism Kocuria rosea was characterized using batch experiments combined with species distribution calculation, SEM-EDS, FTIR, XRD and XPS. The results showed that the coexistence of arsenic plays an active role in Kocuria rosea growth and the removal of uranium under neutral and slightly acidic conditions. U-As complex species of UO2HAsO4 (aq) had a positive effect on uranium removal, while Kocuria rosea cells appeared to have a large specific surface area serving as attachment sites. Furthermore, a large number of nano-sized flaky precipitates, constituted by uranium and arsenic, attached to the surface of Kocuria rosea cells at pH 5 through P=O, COO-, and C=O groups in phospholipids, polysaccharides, and proteins. The biological reduction of U(VI) and As(V) took place in a successive way, and the formation of a chadwickite-like uranyl arsenate precipitate further inhibited U(VI) reduction. The results will help to design more effective bioremediation strategies for arsenic-uranium cocontamination.

Dextran-assisted ultrasonic exfoliation of two-dimensional metal-organic frameworks to evaluate acetylcholinesterase activity and inhibitor screening.

Acetylcholinesterase (AChE) is regarded as a biomarker of Alzheimer's disease (AD), and its inhibitors show great potential in AD therapy as AChE can increase the neurotoxicity of the amyloid component that induces AD. Because of this, it is crucial and significant to develop a simple and highly sensitive strategy to monitor AChE levels and screen highly efficient AChE inhibitors. Herein, we synthesize an ultrathin two-dimensional (2D) metal-organic framework (MOF) based on copper-catecholate (Cu-CAT) via dextran assisted ultrasound exfoliation, followed by construction of a sensitive sensor for the monitoring AChE and screening of its inhibitors. By adding AChE, the acetylthiocholine (ATCh) substrate is hydrolyzed to be thiocholine (TCh), which decreases the peroxidase-like activity of Cu-CAT nanosheets (Cu-CAT NSs), impairing the signal reaction of 3,3',5,5'-tetramethylbenzidine (TMB) to oxidized-TMB (ox-TMB). In the presence of an AChE inhibitor, the signal can be gradually restored. The newly developed sensor shows high sensitivity and selectivity for AChE and huperzine A (HA, an effective drug for AD, an acetylcholine receptor antagonist), as well as for AD drug discovery from traditional Chinese herbs. The limit of detection of the sensor for AChE is 0.01 mU mL-1 and the average IC50 value of HA is 30.81 nM under the optimal of catalysis conditions. Compared with the 3D bulk Cu-CAT, the current 2D Cu-CAT NSs exhibit higher peroxidase activity due to more catalytic active site exposure. This study provides a strategy to prepare an ultrathin 2D MOF with high catalytic activity and new insights for the construction of a biosensor to monitor AChE and new AD drugs.

Outdoor Atmospheric Micro-/Nanomineral-Mediated Organochlorine Pesticides in Sichuan Basin, China: Adsorption, Occurrence, and Risk Assessment.

Atmospheric micro-/nanominerals play an important role in the adsorption, enrichment, and migration of organochlorine pesticides (OCPs). In the present study, the correlations between OCPs and minerals in outdoor atmospheric dustfall were investigated, and the correlations were used to speculate the source of p,p'-(dicofol+dichlorobenzophenone [DBP]), which is the sum of p,p'-dicofol and p,p'-DBP. Atmospheric dustfall samples were collected from 53 sites in the Chengdu-Deyang-Mianyang economic region in the Sichuan basin. In this region, 24 OCPs were analyzed by gas chromatography-tandem mass spectrometry. The average concentration of 24 OCPs was 51.2 ± 27.4 ng/g. The results showed that the concentration of Σ24 OCPs in urban areas was higher than that in suburban areas (p < 0.05). Minerals in atmospheric dustfall were semiquantitatively analyzed by X-ray diffraction. The primary minerals were quartz, calcite, and gypsum. A Spearman correlation analysis of OCPs and minerals showed that low-volatility OCPs could be adsorbed by minerals in atmospheric dustfall. A density functional theory simulation verified that p,p'-(dicofol+DBP) in atmospheric dustfall was primarily derived from the p,p'-dicofol adsorbed by gypsum. Isomeric ratio results suggested that the samples had weathered lindane and chlordane profiles and confirmed that residents in the Sichuan basin used technical dichlorodiphenyltrichloroethane. Finally, the OCPs were evaluated to determine the potential risk of cancer in adults and children from OCP exposure. Exposure to OCPs via atmospheric dustfall was safe for adults. The cancer risk for children exposed to OCPs was slightly lower than the threshold value (10-6 ) under a high dust ingestion rate, which poses a concern. Environ Toxicol Chem 2023;42:594-604. © 2022 SETAC.

Laparoscopic surgery for stage III neuroblastoma: A case report.

Laparoscopic surgery for malignant solid tumors is still in the stage of clinical exploration. Neuroblastoma is a common solid tumor in children. The present study discussed significance and feasibility of complete resection of stage III neuroblastoma by laparoscopic surgery and its safety and effectiveness was compared with traditional surgery. For children suffering from neuroblastoma with large tumor volume and vascular invasion, preoperative chemotherapy can be given and minimally invasive laparoscopic surgery can be one option to be considered when the tumor volume is <6 cm. During the operation, the tumor tissue can be removed by segmental resection and the removal of as much tumor tissue as possible is an important factor in improving the prognosis. Laparoscopic minimally invasive surgery is associated with minimal surgical trauma and quick recovery of patients, and children can receive postoperative chemotherapy as early as possible, which is conducive to good recovery. Basically, the prerequisite and requirements for performing this operation are professional laparoscopic skills and an experienced team.

Surface biomineralization of uranium onto Shewanella putrefaciens with or without extracellular polymeric substances.

The influence of extracellular polymeric substances (EPS) on the interaction between uranium [U(VI)] and Shewanella putrefaciens (S. putrefaciens), especially the U(VI) biomineralization process occurring on whole cells and cell components of S. putrefaciens was investigated in this study. The removal efficiency of U(VI) by S. putrefaciens was decreased by 22% after extraction of EPS. Proteins were identified as the main components of EPS by EEM analysis and were determined to play a major role in the biosorption of uranium. SEM-EDS results showed that U(VI) was distributed around the whole cell as 500-nanometer schistose structures, which consisted primarily of U and P. However, similar uranium lamellar crystal were wrapped only on the surface of EPS-free S. putrefaciens cells. FTIR and XPS analysis indicated that phosphorus- and nitrogen-containing groups played important roles in complexing U (VI). XRD and U LIII-edge EXAFS analyses demonstrated that the schistose structure consisted of hydrogen uranyl phosphate [H2(UO2)2(PO4)2•8H2O]. Our study provides new insight into the mechanisms of induced uranium crystallization by EPS and cell wall membranes of living bacterial cells under aerobic conditions.

Preparation and characterization of chitosan/pullulan film loading carvacrol for targeted antibacterial packaging of chilled meat.

In this research, the common microorganisms in chilled meat were used as the targeted antibacterial objects. Chitosan, pullulan, and carvacrol were chosen to prepare the edible antibacterial film. The effects of different concentrations of carvacrol on the microstructure, physical properties and antibacterial properties of the films were investigated. The results showed that the antibacterial activity of chitosan/pullulan film (CS/PU) was unsatisfactory, when carvacrol was added, the antibacterial activity of the chitosan/pullulan/carvacrol film (CS/PU/CAR) improved significantly (p < 0.05), and the water vapor permeability (WVP) of the CS/PU/CAR decreased significantly (p < 0.05). When the carvacrol concentration was higher than 1.25% (w/v), the tensile strength and percentage elongation at break of the CS/PU/CAR increased significantly (p < 0.05), and the CS/PU/CAR exhibited satisfying antibacterial activity against the common bacteria in chilled meat such as Pseudomonas fluorescens, Listeria monocytogenes, Escherichia coli, Pseudomonas putida, Enterobacter cloacae, and Staphylococcus aureus. Finally, the CS/PU/CAR film was applied to the preservation of chilled goat meat and extended the shelf life of goat meat to more than 15 days. These results suggested that the targeted CS/PU/CAR film can be used as biodegradable films for the active packaging of chilled meat.

Efficient extraction of U(VI) from uranium enrichment process wastewater by amine-aminophosphonate-modified polyacrylonitrile fibers.

The enrichment and recovery of U(VI) from low-level radioactive wastewater in the process of uranium enrichment is important for the sustainable development of nuclear energy and environmental protection. Herein, a novel amine-aminophosphonate bifunctionalized polyacrylonitrile fiber (AAP-PAN), was prepared for the extraction of U(VI) from simulated and real uranium-containing process wastewater. The AAP-PAN fiber demonstrated a maximum adsorption capacity of 313.6 mg g-1 at pH = 6.0 and 318 K in the batch experiments. During the dynamic column experiment, over 99.99% removal of U(VI) could be achieved by the fiber using multi-ion simulated solution and real wastewater with an excellent saturation adsorption capacity of 132.0 mg g-1 and 72.5 mg g-1, respectively. It also exhibited an outstanding reusability for at least 5 cycles of adsorption process. The mechanism for U(VI) removal was studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis in the assist of simulation calculation. It suggested that the amine and aminophosphonate groups can easily bind uranyl ions due to U(VI) is more likely to combine with oxygen atoms of CO and PO, respectively.

Nanobiocatalyst consisting of immobilized α-amylase on montmorillonite exhibiting enhanced enzymatic performance based on the allosteric effect.

Enzyme immobilization on nanostructured substrates is an emerging method for the efficient development of nanobiocatalysts to enhance enzymatic performance. In this study, a novel α-amylase nanobiocatalytic system was constructed based on the allosteric activation of the enzyme and its immobilization on a natural nanostructured mineral montmorillonite. The strategy of allosteric modulation and immobilization, equipped the immobilized α-amylase with higher catalytic activity and greater stability (compared to those of free α-amylase) over a broad range of pH values (4.5-9.0) and temperatures (30-80 °C). Kinetic experiments revealed that although the immobilized α-amylase possessed a considerably lower affinity for its substrate, its catalytic activity was higher than that of free α-amylase, likely owing to allosteric modulation. Thus, this study demonstrates a convenient and environmentally benign immobilization strategy to construct a nanobiocatalytic α-amylase system that exploits the phenomenon of allosteric activation of the enzyme and lays the foundation for further industrial applications.

Production of a Class IIb Bacteriocin with Broad-spectrum Antimicrobial Activity in Lactiplantibacillus plantarum RUB1.

Bacteriocins produced by lactic acid bacteria have potential use as natural food preservatives, which may alleviate current problems associated with the overuse of antibiotics and emerging multi-drug-resistant microbes. In this work, Lactiplantibacillus plantarum RUB1 was found to produce a class IIb bacteriocin with strong antibacterial activity. Except for plnXY encoding putative proteins, L. plantarum RUB1 contains most genes in five operons (plnABCD, plnGHSTUVW, plnMNOP, plnIEF, and plnRLJK) related to bacteriocin synthesis. Adding low (100 and 500 ng/mL) and medium (1 µg/mL) concentrations of PlnA to broth promoted bacteriocin production and upregulated bacteriocin gene plnA, while high concentrations (50 and 200 µg/mL) inhibited expression of these genes. Co-culturing L. plantarum RUB1 with Enterococcus hirae 1003, Enterococcus hirae LWS, Limosilactobacillus fermentum RC4, L. plantarum B6, and even Listeria monocytogenes ATCC 19111 and Staphylococcus aureus ATCC 6538 enhanced bacteriocin activity and expression of bacteriocin-related genes. This study verifies that PlnA can indeed upregulate the expression of bacteriocin genes, and also bacteriocin production can be induced by co-culture with some specific bacteria or their cell-free supernatants. Bacteriocin production by L. plantarum RUB1 is mediated by a quorum sensing mechanism, directly influenced by autoinducing peptide or specific strains. The findings provide new methods and insight into bacteriocin production mechanisms.

Interface interaction between high-siliceous/calcareous mineral granules and model cell membranes dominated by electrostatic force.

High-siliceous/calcareous mineral granules may cause cytotoxicity by attaching to cell membranes. In this research, giant (GUVs) and small unilamellar vesicles (SUVs) were used as model membranes for studying the interaction between high-siliceous/calcareous mineral granules (micro calcite, micro quartz, nano calcium carbonate, and nano silica) and artificial membranes. Confocal laser scanning microscopy (CLSM) and fluorescence labeling experiments suggest that nano calcium carbonate (nano CaCO3) and nano silica (nano SiO2) induce gelation by disrupting the oppositely charged membranes, indicating the important role of electrostatic forces. Thereby, the mineral granule size affects the electrostatic interactions and thus leading to the damage of the membranes. FTIR spectra and molecular dynamics reveal that mineral granules mainly interact with -PO2-, -OH, and -C-N(CH3)3+ groups in phospholipids. The electrostatic force between nano minerals and phospholipids is greater in the case SiO2 when compared to CaCO3. Moreover, nano SiO2 forms the strongest hydrogen bond with the -PO2- group as confirmed by FTIR. Thus, nano SiO2 causes the greatest damage to membranes. This research provides a deeper understanding of the mechanism regarding the interaction between inhalable mineral granules and cell membranes.

Speciation Distribution of Heavy Metals in Uranium Mining Impacted Soils and Impact on Bacterial Community Revealed by High-Throughput Sequencing.

This study investigated the influence of heavy metals on bacterial community structure in a uranium mine. Soils from three differently polluted ditches (Yangchang ditch, Zhongchang ditch, and Sulimutang ditche) were collected from Zoige County, Sichuan province, China. Soil physicochemical properties and heavy metal concentrations were measured. Differences between bacterial communities were investigated using the high-throughput sequencing of the 16S rRNA genes. The obtained results demonstrated that bacterial richness index (Chao and Ace) were similar among three ditches, while the highest bacterial diversity index was detected in the severely contaminated soils. The compositions of bacterial communities varied among three examined sites, but Proteobacteria and Acidobacteria were abundant in all samples. Redundancy analysis revealed that soil organic matter, Cr and pH were the three major factors altering the bacterial community structure. Pearson correlation analysis indicated that the most significant correlations were observed between the contents of non-residual Cr and the abundances of bacterial genera, including Thiobacillus, Nitrospira, and other 10 genera. Among them, the abundances of Sphingomonas and Pseudomonas were significant and positively correlated with the concentrations of non-residual U and As. The results highlighted the factors influencing the bacterial community in uranium mines and contributed a better understanding of the effects of heavy metals on bacterial community structure by considering the fraction of heavy metals.

Effects and mechanism of riboflavin on the growth of Alcaligenes faecalis under bias conditions.

Some microorganisms can utilize photoelectrons and electrode electrons. Exogenous electrons generate enough energy for growth, and electron shuttles may accelerate this process. This research data supported photoelectron-responsive microorganism Alcaligenes faecalis was effected by the growth metabolism due to bias and electron shuttle riboflavin (RF) with an adaptive screening voltage under oligotrophic conditions. A slight change was observed in the redox property of RF. RF played the role of an electron shuttle. Microbial extracellular metabolites could bind additional nicotinamide adenine dinucleotide (NADH) species with RF. The intracellular protein content in the group of RF-Bias was 1.94, 1.93 and 4.02 times higher than those in the RF, bias and control groups, respectively, while the corresponding intracellular contents of humus were 1.10, 0.93 and 1.42 times higher. The content of CoA in RF-Bias, RF and bias increased to 116.0%, 108.5% and 103.8%, respectively. The organic acids of the RF-Bias group in the Krebs cycle are more advanced than those of other groups. Overall, in the Krebs cycle, RF and bias facilitated the growth and metabolism of A. faecalis. Finally, a mechanism was proposed, showing that the electron transfer chain and the Krebs cycle are stimulated by RF and bias.

Improving photoelectrochemical reduction of Cr(VI) ions by building α-Fe2O3/TiO2 electrode.

Photoelectrochemical process is an environmentally friendly technology and has a wide application in the control of environmental pollutants. Efficient nanophotocatalysts responsive to visible light are still highly attractive. In this work, α-Fe2O3/TiO2 were grown on fluorine doped tin oxide (FTO) substrates by hydrothermal method for photoelectrochemical reduction of Cr(VI). Compared with the separate α-Fe2O3 and TiO2 electrodes, the composite α-Fe2O3/TiO2 electrodes show higher photocurrent density. Under visible light irradiation, 100% removal efficiency of Cr(VI) was obtained after 40 min treatment. The composite α-Fe2O3/TiO2 electrodes showed an enhanced absorbance in visible light region and had good stability to photoelectrochemical reduction of Cr(VI). The role of hole scavengers (citric acid and oxalic acid) and pH values was systematically investigated. This novel intensification approach provides new insight on the application of photoelectrochemical reduction in environmental remediation.

A synergetic biomineralization strategy for immobilizing strontium during calcification of the coccolithophore Emiliania huxleyi.

The coccolithophore species Emiliania huxleyi has one of the most global distributions in the modern oceans. They are characteristically covered with calcite scales called coccoliths. In this study, stable strontium immobilization during the calcification process was investigated to indirectly assess a proposed bioremediation approach for removing Sr2+ contamination from marine environments. Results indicate that E. huxleyi has high Sr2+ tolerance and removal efficiency in response to Sr2+ stress ranging from 5.6 to 105.6 ppm. Sr2+ immobilization during E. huxleyi calcification indicates a concentration-dependent synergistic mechanism. At lower concentrations of Sr2+ (25.6 ppm), Sr2+ is incorporated into coccoliths through competitive supply between Sr2+ and Ca2+. In addition, calcite productivity decreases with increased Sr2+ removal efficiency due to crystallographic transformation of coccoliths from hydrated calcite into aragonite at 55.6 ppm Sr2+. Further formation of strontianite at 105.6 ppm Sr2+ is due to precipitation of Sr2+ on the edge of the rims and radial arrays of the coccoliths. Our study implies that coccolithophores are capable of significant removal of Sr2+ from the marine environment.

Synergistic interface behavior of strontium adsorption using mixed microorganisms.

The proper handling of low-level radioactive waste is crucial to promote the sustainable development of nuclear power. Research into the mechanism for interactions between bacterium and radionuclides is the starting point for achieving successful remediation of radionuclides with microorganisms. Using Sr(II) as a simulation radionuclide and the mixed microorganisms of Saccharomyces cerevisiae and Bacillus subtilis as the biological adsorbent, this study investigates behavior at the interface between Sr(II) and the microorganisms as well as the mechanisms governing that behavior. The results show that the optimal ratio of mixed microorganisms is S. cerevisiae 2.0 g L-1 to B. subtilis 0.05 g L-1, and the optimal pH is about 6.3. Sr(II) biosorption onto the mixed microorganisms is spontaneous and endothermic in nature. The kinetics and the equilibrium isotherm data of the biosorption process can be described with pseudo-second-order equation and the Langmuir isotherm equation, respectively. The key interaction between the biological adsorbent and Sr(II) involves shared electronic pairs arising from chemical reactions via bond complexation or electronic exchange, and spectral and energy spectrum analysis show that functional groups (e.g., hydroxyl, carboxyl, amino, amide) at the interface between the radionuclide and the mixed microorganisms are the main active sites of the interface reactions.