Cap Content Research Articles

Efficacy of P-sorbent material combined with aquatic plants in controlling nutrient release from urban lake sediment: Field investigation

The release of stored nutrients from sediments is thought to substantially affect water quality in urban lakes. To explore the efficiency of different in-situ remediation methods on controlling high internal urban lake sediments, 120 days of field-enclosure experiments were conducted to investigate the efficacy of P-sorbent materials combined with aquatic plants in controlling nutrient release from urban-lake sediments. The lanthanum-modified clay (LMC) effectively reduced sediment P release flux and could temporarily lead to a small increase in N concentration in the overlying water. In contrast, Vallisneria spiralis (V. spiralis) has a relatively weak effect on controlling nutrient release and can even cause an increase in P concentration. The combined restoration technique of V. spiralis + LMC can overcome the drawbacks of a single method, reduce the nutrient content in overlying water, and inhibit the sediment internal release. Relative to the control, the V. spiralis + LMC treatment reduced mobile P content by 52.5% and increased Ca-P content by 34.5%. The added lanthanum contained material can quickly bind the readily released P in sediment and porewater, transforming it into intert P over time. Submerged macrophytes can absorb active P in water and sediments and transport oxygen to sediments promoting denitrification and N removal. The combined restoration technique synergistically combines the high P sorption affinity of LMC and the substrate improvement effect of V. spiralis, thus realizing the long-term control of endogenous release in urban lakes. This approach holds great promise for restoring urban lakes with high endogenous nutrient loading.

Isolation, Characterization, Moisturization and Anti-HepG2 Cell Activities of a Novel Polysaccharide from Cyanobacterium aponinum.

Polysaccharides from cyanobacteria are extensively reported for their complex structures, good biocompatibility, and diverse bioactivities, but only a few cyanobacterial species have been exploited for the biotechnological production of polysaccharides. According to our previous study, the newly isolated marine cyanobacterium Cyanobacterium aponinum SCSIO-45682 was a good candidate for polysaccharide production. This work provided a systematic study of the extraction optimization, isolation, structural characterization, and bioactivity evaluation of polysaccharides from C. aponinum SCSIO-45682. Results showed that the crude polysaccharide yield of C. aponinum reached 17.02% by hot water extraction. The crude polysaccharides showed a porous and fibrous structure, as well as good moisture absorption and retention capacities comparable to that of sodium alginate. A homogeneous polysaccharide (Cyanobacterium aponinum polysaccharide, CAP) was obtained after cellulose DEAE-52 column and Sephadex G-100 column purification. CAP possessed a high molecular weight of 4596.64 kDa. It was mainly composed of fucose, galactose, and galacturonic acid, with a molar ratio of 15.27:11.39:8.64. The uronic acid content and sulfate content of CAP was 12.96% and 18.06%, respectively. Furthermore, CAP showed an in vitro growth inhibition effect on human hepatocellular carcinoma (HepG2) cells. The above results indicated the potential of polysaccharides from the marine cyanobacterium C. aponinum SCSIO-45682 as a moisturizer and anticancer addictive applied in cosmetical and pharmaceutical industries.

Practice Analysis: Developing a Content Outline for the Child Abuse Pediatrics Certification Exam.

The examination by which physicians achieve board certification in CAP should reflect the knowledge and skills required of the modern practitioner. The American Board of Pediatrics (ABP) assembled a 12-member volunteer panel of practicing child abuse pediatricians to conduct a practice analysis. In the first phase of the project, the panel identified and documented the practice domains, tasks, knowledge, and skills required for clinical practice. During the second phase, the panel organized testable knowledge areas into content domains and subdomains and updated the ABP CAP content outline. Feedback on the revised outline was requested from all ABP board-certified child abuse pediatricians via an online survey and results from the survey informed final revisions to the outline.

Preparation and properties of chitosan/gelatin film containing capsaicinoid for hemostasis and antibacterial

Blood loss resulting from accidents or surgery is a worrying health problem. This is because hemorrhage can occur and cause death. Therefore, the development of safe and effective hemostatic materials is important. Hemostatic agents (Ha) made from the composite of chitosan, gelatin, and glycerol mixtures and capsaicinoids (Cap) at various compositions 0, 1, 2, 4, 6 and 12 wt%. The films forming were prepared by casting with the aim of obtaining an environmentally friendly material for intraoperative hemostasis. The characterizations of the samples were performed by physicochemical, morphological, hemostasis test, functional groups, antibacterial, and mechanical properties were evaluated. The samples received are flexible and transparent. It was found that 6 wt% Cap showed the optimization in stopping bleeding, and Cap content of 12 wt% was optimized for antibacterial properties both Staphylococcusaureus and Escherichia coli. The results show that the addition Cap into chitosan/gelatin film based Ha has high potential as a hemostatic product, and there is a very interesting trend in the development of hemostatic and antibacterial materials in the future.

Effect of Initial pH on the Microbial Growth, Final pH Value, Crude Protein and Ash Level of Agaricus bisporus Cap and Stem in Submerged Fermentation

The aim of the study was to investigate the effect of submerged fermentation with Lactobacillus spp. on the nutritional composition of Agaricus bisporus cap and stem. Fresh A. bisporus was provided, and the cap and stem parts were separated and cut into small pieces. Afterward, distilled water (400 ml) and urea (8.4 g) were added to the mushroom parts (100 g) and placed in different fermentation flasks. The fermentation flasks containing mushroom caps or stems were divided into two groups, and the pH levels of the fermentation medium were adjusted to 6 and 7. Fermentation flasks were autoclaved at 121°C for 15 minutes and Lactobacillus spp. was inoculated to each flask at 1 ml (108 CFU/ml). A positive control group was formed by allocating one uninoculated flask for each replicate of each pH value. Fermentation flasks were incubated for 48 hours at 30°C. After fermentation, fermented and inoculated mushroom cap and stem were analyzed to determine the crude protein, ash content, Lactobacillus spp. count and pH value. Lactobacillus spp. count was higher (P=0.028) in the pH 6 group of mushroom cap and tended to be higher (P=0.078) in the pH 6 group of mushroom stems compared with the pH 7 group. Submerged fermentation decreased (P<0.001) the ash content of the mushroom cap and stem in both pH values except the cap with pH 7 compared with the uninoculated mushroom. Similarly, the fermented mushroom cap and stem had lower (P<0.01) final pH values in both initial pH values. Lactobacillus spp. increased (P<0.001) the crude protein content of the mushroom cap with pH 6 but did not alter the crude protein content with pH 7. Besides, submerged fermentation decreased (P<0.001) the crude protein content of mushroom stem with both pH values. The results indicate that submerged fermentation using Lactobacillus spp. can be used to improve the nutritional composition of mushroom caps with pH 6.

Co-occurrence of organophosphate esters and phosphorus fractions in river sediments: Implications for pollution prediction and environment risk assessment

Organophosphate esters (OPEs) and phosphorus (P) are widespread pollutants in aquatic ecosystems, presenting potential ecological risks. However, there is still a lack of comprehensive understanding of their relationships in sediments. In this study, we investigated the co-occurrence and behaviors of the OPEs and P in urban river sediments. The results indicated serious OPE and P pollution in the study area, with substantial spatial variations in the contents and compositions. The OPE congeners and P fractions exhibited different correlations, particularly more significant linear relationships (R = 0.455 - 0.816, p < 0.05) were observed between the aryl-OPEs and P fractions, potentially due to the influence from sources, physicochemical properties, and total organic carbon. About 56 to 71% of variability in predicting the concentrations of aryl-OPE can be explained by the multiple linear regression model using the Fe/Al- and Ca-bound P contents. The study regions exhibited greater aryl-OPEs ecological risks were consistent with the regions with more serious Total P pollution levels. This study represents the first report demonstrating the potential of Fe/Al-P and Ca-P contents in predicting aryl-OPE contents in heavily polluted sediments, providing a useful reference to comprehensively assess the occurrence and environmental behaviors of aryl-OPEs in anthropogenic polluted sediments.

Simultaneous removal of nitrate nitrogen and orthophosphate by electroreduction and electrochemical precipitation

Electrochemical methods can effectively remove nitrate nitrogen (NO3-N) and orthophosphate phosphorus (PO4-P) from wastewater. This work proposed a process for the simultaneous removal of NO3-N and PO4-P by combining electroreduction with electrochemically-induced calcium phosphate precipitation, and its performance and mechanisms were studied. For the treatment of 100 mg L–1 NO3-N and 5 mg L–1 PO4-P, NO3-N removal of 60–90% (per cathode area: 0.25–0.38 mg h–1 cm–2) and 80–90% (per cathode area: 0.33–0.38 mg h–1 cm–2) could be acquired within 3 h in single-chamber cell (SCC) and dual-chamber cell (DCC), while P removal was 80–98% (per cathode area: 0.10–0.12 mg h–1 cm–2) in SCC after 30 min and 98% (per cathode area: 0.37 mg h–1 cm–2) in DCC within 10 min. The faster P removal in DCC was due to the higher pH and more abundant Ca2+ in the cathode chamber of DCC, which was caused by the cation exchange membrane (CEM). Interestingly, NO3-N reduction enhanced P removal because more OH– can be produced by nitrate reduction than hydrogen evolution for an equal-charge reaction. For 10 mg L–1 PO4-P in SCC, when the initial NO3-N was 0, 20, 100, and 500 mg L–1, the P removal efficiencies after 1 h treatment were < 10%, 45–55%, 86–99%, and above 98% respectively. An increase in Ca2+ concentration also promoted P removal. However, Ca and P inhibited nitrate reduction in SCC at the relatively low initial Ca/P, as CaP on the cathode limited the charge or mass transfer process. The removal efficiency of NO3-N in SCC after 3 h reaction can reduce by about 17%, 40%, and 34% for Co3O4/Ti, Co/Ti, and TiO2/Ti. The degree of inhibition of P on NO3-N removal was related to the content and composition of CaP deposited on the cathode. On the cathode, the lower the deposited Ca and P, and the higher the deposited Ca/P molar ratio, the weaker the inhibition of P on NO3-N removal. Especially, P had little or even no inhibition on nitrate reduction when treated in DCC instead of SCC or under high initial Ca/P. It is speculated that under these conditions, a high local pH and local high concentration Ca2+ layer near the cathode led to a decrease in CaP deposition and an increase in Ca/P molar ratio on the cathode. High initial concentrations of NO3-N might also be beneficial in reducing the inhibition of P on nitrate reduction, as few CaP with high Ca/P molar ratios were deposited on the cathode. The evaluation of the real wastewater treatment was also conducted.

Impact of Long-term Use of Fertilizers and Manure on Distribution of Soil-inorganic Phosphorus Fractions in a Vertisol

The field experiment was conducted during the kharif season under the AICRP on Long-Term Fertilizer Experiment at the Research Farm, Department of Soil Science and Agricultural Chemistry, JNKVV, Jabalpur (M.P.), India. The investigation was carried out to assess the distribution of P fractions in Vertisol after the harvesting of the soybean crop. Eight treatments were imposed with four replications in a simple randomized block design. The treatments were applied in combination with different doses of fertilizer viz., T1 (50% NPK), T2 (100% NPK), T3 (150% NPK), T4 (100% N), T5 (100% NP), T6 (100% NPK+FYM), T7 (100% NPK-S), and T8 (control). Through the findings, the soil pH and electrical conductivity (dS m-1) did not show significant changes even after the long-term application of various fertilizer levels compared to their initial values. The treatment with 100% NPK + FYM exhibited the highest organic carbon (g kg-1) content and available N, P, and K (kg ha-1) content over the control. The various forms of phosphorus in the soil were observed in the following order: Ca-P &gt; Fe-P &gt; Al-P &gt; Occluded-P &gt; Saloid-P . The Ca-P content was highest when 100% NPK fertilizer and farmyard manure (FYM) were used together. The analysis showed that the presence of saloid-P significantly influences the availability of phosphorus in Vertisol soil. Based on the current investigation, it is recommended to use integrated nutrient management, which includes both 100% NPK fertilizer and FYM, to prevent phosphorus deficiency in soybean cultivation in Vertisol.

Effects of experimental bleaching gels containing co-doped titanium dioxide and niobium pentoxide combined with violet light.

The objective of the study is to evaluate the bleaching potential of 6% hydrogen peroxide (6% HP) gels containing NF_TiO2 or Nb2O5 irradiated with a violet LED light and the effects on enamel mineral content and surface morphology. Particles were synthesized, and experimental gels were chemically analyzed by preliminary and accelerated stability tests, pH, and HP decomposition rate. Bovine enamel blocks were treated with 6% HP gels containing (n = 10): 5% NF_TiO2, 5% Nb2O5, 2.5% NF_TiO2 + 2.5% Nb2O5 or without particles (6% HP), irradiated or not with LED, and the control was treated with 35% HP. Color (∆E00) and whitening index (∆WID) variations, surface microhardness (SH), average roughness (∆Ra), Ca-P concentration (EDS), and enamel morphology (SEM) were assessed. Bleaching was performed in 3 sessions of 30min and 7-day intervals. Data were submitted to two- (pH, decomposition rate, ∆E00, and ∆WID) or three-way ANOVA and Bonferroni (SH), Kruskal-Wallis (∆Ra), and Dunnettests (α = 0.05). No changes in the gel's color, odor, or translucency were observed. ThepH (6 to 6.5) remained stable over time, and light irradiation boosted the HP decomposition rate. NF_TiO2 and Nb2O5-containing gels displayed higher ∆E00 and ΔWID when light-irradiated (p < 0.05). Nb2O5 and Nb2O5 + NF_TiO2 decreased enamel SH (p < 0.05), but no SH changes were found among groups (p > 0.05). No differences among groups were noted in ∆Ra, Ca-P content, and enamel morphology after treatments (p > 0.05). Experimental light-irradiated 6% HP gels containing NF_TiO2 or Nb2O5 were chemically stable and exhibited bleaching potential comparable with 35% HP. Low-concentrated HP gelscontaining NF_TiO2 or Nb2O5 and light-irradiatedstand as a possible alternative to in-office bleaching.

Effects of calcium glycerophosphate concentration on micro-arc oxidation coating of Mg alloy

Due to its good biocompatibility and compatible hardness with human bones, magnesium (Mg) alloy is considered as a promising material for bone nails and implants. However, Mg and its alloys are characteristics of active chemical properties and high corrosion rate, which is detrimental to the recovery of patients implanted with Mg alloy bone scaffold. In the present work, to retard the corrosion of the Mg alloy, calcium glycerophosphate (C3H7CaO6P•H2O) was added in the electrolyte to form the micro-arc oxidation (MAO) coatings. Various experimental techniques such as XRD, SEM and EDS have been used to characterize the surface morphology and phase composition of MAO coatings. MAO coatings of different CaP content were studied to explore the synergetic effect between the biocompatibility and corrosive properties by means of electrochemical measurements, hemolysis and pyrogen test. The results showed that higher CaP content can improve the biocompatibility and corrosion resistance while decelerating the hemolysis rate.

Effects of Oyster Shell Powder and Lime on Availability and Forms of Phosphorus and Enzyme Activity in Acidic Paddy Soil

Soil acidification improvement in the main grain production regions of southern China is an important issue to enhance the quality of cultivated land and promote grain yield. In order to explore the effects of oyster shell powder and lime on acidity and availability and inorganic forms of phosphorus in acidic paddy soil, a pot experiment was performed using oyster shell powder and lime amendments with dosages of 0.05%, 0.10%, and 0.15%. The results showed that both oyster shell powder and lime significantly (P<0.05) increased the pH and decreased exchangeable acid content of paddy soil. The improvement effects increased with the dosage of soil amendments. Under the same amendment dosage, the effects of lime on soil pH and acidity were higher than those of oyster shell powder. Both lime and oyster shell powder significantly increased the content of available P extracted using H2SO4-P, Bray-1 P, and Olsen-P techniques. The contents of inorganic P in soils decreased in the order of Fe-P>Al-P>Ca-P. The application of lime and oyster shell powder significantly increased the contents of Al-P and Fe-P in soil. Compared with the control treatment, lime and oyster shell power increased Al-P and Fe-P by 26.3%-37.4% and 7.9%-23.7%, respectively. However, there was no significant difference in Al-P content among treatments of the three amendment dosages. The contents of Fe-P and Ca-P in soils increased with an increased dosage of amendments. The activities of DHA, ALP, and IPP and the copy number of the phoD gene in soil increased with the application of lime and oyster shell powder, whereas the activities of ACP and the copy numbers of phoC and pqqC decreased. The application of lime and oyster shell powder at a rate of 0.10% and 0.15% significantly (P<0.05) increased the yield of rice. The lime and oyster shell powder treatments at the dosage of 0.15% increased rice yield by 34.2% and 46.8%, respectively, whereas the amendment had no significant effect on straw biomass of the rice crop. Correlation analysis showed that soil pH and the ALP activity were significantly positively correlated with inorganic P and available P contents, respectively. These results suggested that lime and oyster shell power could effectively increase the content of available phosphorus by eliminating soil acidity and improving the phosphatase activity, which played a positive role in increasing crop yield.

TH1 lymphocytes in the perivascular adipose tissue correlate with plaque composition and increase the risk of intraplaque haemorrhages in coronary arteries: an autopsy study

Abstract Background Inflammation in the perivascular adipose tissue (PvAT) might play a role in coronary artery disease. The T helper 1 (Th1) lymphocytes are the most popular T helper (Th) lymphocytes in atherosclerotic plaques and are proatherogenic. However, the association between the Th1 and Th lymphocytes in the PvAT with coronary atherosclerosis composition was not previously investigated in humans. Purpose We investigated the correlation between Th CD4+ and Th1 CD4+CXCR3+ lymphocytes in the PvAT with atherosclerotic plaque composition. Methods Human coronary arteries were freshly dissected with adjacent PvAT. The most important atherosclerotic plaque was selected of the main coronary arteries and was stained with hematoxylin-eosin, Masson's trichrome, and Verhöeff. We calculated the percentage of arterial obstruction, intima-media thickness, the minimum fibrous cap thickness, and the percentual of collagen, smooth muscle cells (SMC), fibrous cap, calcification, lipid, necrosis, and intraplaque hemorrhage. The atherosclerotic plaques were classified in stable and unstable plaques (hemorrhages and thrombus). The density of Th lymphocytes (CD4+), Th1 (CD4+CXCR3+), and the ratio of Th1/Th were detected using the immunohistochemistry double staining technique. The densities and the ratio Th1/Th were correlated with plaque composition using linear, negative binomial, or Poisson regressions models with clustering for multiple measures in the same individual and adjusted for age, sex, hypertension, diabetes, body mass index, sedentary lifestyle, smoking, and alcohol consumption. Results We evaluated a sample of 126 coronary arteries from 58 subjects. The individuals were older (70.4±14.3 years old), sex was equally distributed, 74% had hypertension, and 40% diabetes. In multivariate analysis, the Th lymphocytes were negatively correlated with calcification content (β=−0.21, 95% CI: −0.41; −0.006, p=0.043). The Th1 lymphocytes were not correlated with plaque composition; however, the increase of Th1 density in relation to Th lymphocytes was negatively correlated with SMC (β=−35.6, 95% CI: −68.5; −2.83, p=0.03) and the fibrous cap content (β=−11.6, 95% CI: −19.1; −4.05, p=0.003). Additionally, the higher proportion of Th1/Th lymphocytes increased the risk of intraplaque haemorrhages compared to stable coronary plaques (OR=15.5, 95% CI: 1.23; 196.4, p=0.03). Conclusions The increase of pro-inflammatory Th1 lymphocytes in the PvAT was correlated to the decrease of components in atherosclerotic plaques related to plaque stabilization, such as SMC and fibrous cap content. Additionally, the increase in the proportion of pro-inflammatory Th1 lymphocytes in the PvAT also increases the risk of intraplaque haemorrhages in coronary arteries. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): São Paulo Research Foundation (FAPESP) Figure 1Figure 2

Adsorption Behavior of Phosphate by CaO2 Remolded Sediment

This study simulated the state of CaO2 loss after in situ coverage and examined the bottom 2 cm of sediment after restoration. Observations and elemental analysis of the sediment using scanning electron microscopy (SEM) and X-ray energy spectrometry (EDX) were also performed. The CaO2 remodeling notably changed the structure of the sediment; most of the organic matter and iron-manganese oxide attached to the sediment surface was removed, the porosity of the sediment particles increased, and the Ca2+ content was also increased. CaO2 remodeling stabilized the endogenous phosphorus in the sediment; total phosphorous (TP) was reduced by approximately 20% and potential active phosphorus content was reduced by approximately 30%. Furthermore, the contents of Ca-P and Res-P were significantly increased. The amount of phosphorus released from the remodeled sediment under anaerobic conditions was significantly lower than the original sediment, indicating that the CaO2 remodeling greatly reduced the risk of endogenous phosphorus release. The Langmuir model was more suitable than the Freundlich and Dubinin-Radushkevich models for describing the isothermal adsorption behavior of the CaO2 remodeling, which significantly improved the adsorption capacity of the sediment with respect to phosphate from 1.44 mg·g-1 to 20.91 mg·g-1. The mechanism of adsorption was switched from chemical adsorption to physicochemical adsorption. In addition, the adsorption kinetics of the CaO2 remodeled sediment with respect to phosphate could be best described using the quasi-second-order kinetic model.

Promoting plaque stability by gene silencing of monocyte chemotactic protein-3 or overexpression of tissue factor pathway inhibitor in ApoE-/- mice

Chemokines may promote the formation and instability of atherosclerotic plaque, which is the most common cause of acute coronary syndrome. The aim of this study was to clarify the function of monocyte chemotactic protein-3 (MCP-3) in the stability of atherosclerotic plaque, to determine the role of tissue factor pathway inhibitor (TFPI) on the development and stability of atherosclerotic plaques, and to further elucidate the anti-atherosclerotic mechanism of TFPI with the emphasis on chemokine MCP-3. We constructed an adenovirus-mediated shRNA against mouse MCP-3 (Ad-MCP-3-shRNA) and an adenovirus-containing TFPI (Ad-TFPI), and tranferred them in a model of vulnerable plaque in ApoE-/- mice respectively. Here, we reported that MCP-3-shRNA and TFPI could both reduce the plaque area and decrease the content of lipids and macrophages, on the contrary, the fibrous cap thickness and content of collagen and smooth muscle cells were increased. In addition, the expression of MCP-3 and CC chemokine receptor 2 (CCR2) was decreased by TFPI transfer. These data provide the first in vivo evidence that MCP-3 is a major contributor to the unstability of atherosclerotic plaque and TFPI may exert its anti-atherosclerotic effects and promote stabilisation of plaque at least partly through inhibiting MCP-3/CCR2 pathway, which may be a new therapeutic method for atherosclerosis.

Instrumental texture and sensory preference of vacuum-fried shiitake crisps as affected by isomalto-oligosaccharide pretreatment

ABSTRACT Shiitake (Lentinula edodes) is well-known for its distinct flavor and texture as well as its medicinal and nutritional properties. Small good grade fresh shiitake mushrooms are highly perishable and have a low commodity value in the Taiwan market. As a result, these are frequently used as raw materials for vacuum-fried crisps. However, manufacturers continue to use traditional maltose (MO) syrup with no functional properties as a sweetener, and shiitake stipes are frequently discarded, increasing production costs. Isomalto-oligosaccharide (IMO) is a functional oligosaccharide sweetener with health benefits. The purpose of this research is to study the use of functional IMO in the processing of shiitake crisps to replace MO, and the reusability of stipes. In the manufacture of vacuum-fried shiitake cap and stipe crisps, the 30–40°Brix IMO syrup replaces the 35°Brix MO syrup. Vacuum-fried crisps’ quality characteristics were determined using physicochemical and sensory evaluation. The results showed that centrifuged caps and stipes reach equilibrium after 3 h of being soaked in various concentrations of 90–95°C syrup. The L*, a*, b*, h*, and c* values for the cap crisps decreased with the increase in the level of IMO syrup. The breaking force for the stipe crisps was less than that for cap crisps. The crude protein and crude fat content of vacuum-fried cap and stipe crisps decreased as the level of IMO syrup increased, but the carbohydrate content increased. For a nine-point hedonic test, the sensory scores for cap and stipe crisps without seasoning powder were 6.9–7.4 and 6.1–6.5, respectively. Addition of seasoning powder increased the flavor and overall scores to 8.1–8.2 and 7.2–7.4, respectively. Overall, the addition of IMO syrup reduced the calories and increased the health benefits of vacuum-fried shiitake crisps. Furthermore, the result showed that stipes can also be used to make vacuum-fried crisps and increase profitability for manufacturers.

Effectiveness of dredging on internal phosphorus loading in a typical aquacultural lake

Intensive aquaculture significantly affects the global phosphorus (P) cycle and enhances eutrophication in inland waters. Sediment dredging efficiently removes P-rich sediments from shallow-water eutrophic lakes. However, studies on the effects of sediment dredging on the internal P loading of aquacultural lakes are still lacking. Moreover, the migration and transformation processes of labile P and the mechanisms of sediment P release are unclear. To evaluate dredging effectiveness, we employed two in situ high-resolution sampling techniques to simultaneously measure sediment labile P and porewater soluble reactive P (SRP) and Fe (II) at the millimeter scale. Dredging effectively reduced surface sediment CaP contents and organic matter (OM) below the sediment-water interface (SWI). Moreover, dredging decreased the SRP diffusion flux across the SWI in summer. After dredging, FeP (P bound to Fe, Al, and Mn oxides and hydroxides) and OP (organic P) contents increased by 136% and 48% in the newly formed deposited layer (140 mm thick), respectively. The increased bioavailable P content significantly enhanced the capability of sediment solids to resupply labile P to porewater SRP. The stronger positive correlation between porewater soluble Fe (II) and SRP suggests that Fe redox cycling regulated internal P release. Our results suggest that dredging effectiveness will weaken over time due to the re-deposition of active P, which in turn increases the risk of sediment P release. To curb the release of sediment P, we recommend the implementation of additional in situ restoration techniques that improve the oxide layer of surface sediments and reduce sediment suspension.

Stereolithographic fabrication of three-dimensional permeable scaffolds from CaP/PEGDA hydrogel biocomposites for use as bone grafts

Polyethylene glycol diacrylate–based hydrogels filled with calcium phosphates (CaP, Ca/P < 1.5) were stereolithographically fabricated as three-dimensional permeable biocomposites for bone tissue regeneration, probed by several instrumental techniques (including scanning electron microscopy, infrared and UV–vis spectroscopy), and subjected to rheological/mechanical property analysis. As the CaP content increased from 0 to 10 wt%, Young's modulus and mechanical strength increased from 4 to 11 kPa and from 34 to 167 kPa, respectively. Moreover, the enhanced elastic properties and tuneable swelling behaviour of the fabricated composites made them well suited for bone defect filling.

Stone Matrix Asphalt (SMA) with Construction Waste and Curauá Fiber (Ananas erectifolius)

The SMA mixtures are characterized by a high void ratio, which favors binder draindown. In order to avoid this effect, fibers are added to the mixture, which in this case came from Curauá da Amazônia (Ananas erectifolius). The final composition studied resulted in 75% coarse aggregate, 15% fine aggregate, 10% filler, 0.3% of the Curauá fiber residue, and CAP contents equal to 6.50% and 6.88% for the formulations with SMA-Crushed Stone (reference) and SMA-construction and demolition waste (alternative), respectively. The results showed for the Tensile Strength that the composites with CDW reached higher results. The Resilient Modulus values presented small variations for the set of compositions in all loading levels at a temperature of 25°C. However, at a temperature of 40°C, the aforementioned parameter presented decreases in both researched formulations. In general, at all levels examined, higher results were observed for the alternative mixture (SMA-CDW). It is noteworthy the highest results of this parameter when comparing the compositions with the Curauá fiber residue and the formulations mentioned in the literature, with the presence of other types of fibers. Regarding the increase in temperature, there was a decrease in results for both mechanical parameters (TS, DM), but with lower losses for the SMA-RCD composition.

Comparative Phosphorus Accumulation and Ca-P Content of Two Submerged Plants in Response to Light Intensity and Phosphorus Levels

The micro-environment formed by the photosynthesis of submerged plants is conducive to the formation of CaCO3-P from co-precipitation of calcium and phosphorus in water, thereby permanently removing phosphorus from water to the bottom mud and avoiding secondary pollution after plants decay. However, CaCO3-P co-precipitation shows obvious specific-differences and environmental dependencies. In the present study, two different submerged plants, Myriophyllum aquaticum and Potamogeton crispus, were used as the research objects. Two variables, inorganic phosphorus level (0, 0.2, and 2 mg·L-1) and light intensity [66 μmol·(m2·s)-1 and 110 μmol·(m2·s)-1], were set. After cultivating for a week, the plant relative growth rate, plant total phosphorus, plant ash phosphorus, and Ca-P were measured to analyze the actual ability of phosphorus accumulation and clarify the effect of plant corruption on phosphorus increase in the water body. Results revealed that under various culture conditions, the relative growth rates (RGR) of P. crispus were significantly higher than those of M. aquaticum, and RGR reached the maximum at a P level of 2 mg·L-1 and a light intensity of 66 μmol·(m2·s)-1. The addition of inorganic phosphorus significantly affected plant ash phosphorus of the two plants (P. crispus 95.681%, M. aquaticum 85.432%), and the highest value of Ca-P content in the ash phosphorus of the two submerged plants appeared at a high phosphorus level. The total phosphorus in P. crispus was lower than that in M. aquaticum under various treatments, but the total ash phosphorus and Ca-P levels were higher than those in M. aquaticum. Consequently, M. aquaticum and P. crispus can effectively accumulate phosphorus during growth. However, the actual ability of P. crispus of removing phosphorus from water by the formation of CaCO3-P was higher than that of M. aquaticum at a P level of 2 mg·L-1.

Organic management improves soil phosphorus availability and microbial properties in a tea plantation after land conversion from longan (Dimocarpus longan)

Studies on the transformation of P fractions under different land uses and management practices remain scarce, especially in tropical regions. Hence, we investigated the P fraction, microbial communities and soil chemical properties after the conversion of a longan orchard (LO) into an organic tea plantation (OTP) and a conventional tea plantation (CTP) in Hainan, China. At 0–10 cm and 10–20 cm soil depths, the conversion of the LO into the OTP increased the contents of labile P (Resin-P, NaHCO3-Pi and NaHCO3-Po), moderately labile P (NaOH-Pi and NaOH-Po) and occluded P (Sonicate-Pi and Sonicate-Po) but decreased the contents of Ca-P (HCl-Pi) and residual P (stable P), whereas converting the LO into the CTP increased the Ca-P and residual P but decreased the labile P, moderately labile P and occluded P. In addition, at the 0–10 cm soil depth, the bacteria, fungi, actinomycetes, arbuscular mycorrhizal fungal (AMF) and total phospholipid fatty acid (PLFA) biomass were decreased in the CTP, but only the total PLFA was increased in the OTP. However, at the 10–20 cm soil depth, the total PLFA, fungi, and AMF were increased in the OTP, whereas all the PLFA biomarkers remained unchanged in the CTP compared to those in the LO. Furthermore, the labile P, moderately labile P, occluded P and Ca-P in the 0–10 cm layer were related to the soil chemical properties and microbially related groups such as the TK, NO3−, NH4+, acid phosphatase activity (APA), fungi, AMF and bacteria. However, at the 10–20 cm soil depth, these fractions were only associated with soil chemical properties such as the TK, NO3−, NH4+ and APA. Our results revealed that the land use altered the soil P fractions as well as the microbial biomass and activity related to soil P cycling, and organic management practices enhanced the soil P availability more than conventional management practices.