Evaluating Nicotinamide Adenine Dinucleotide for Its Effects on Halo Blight of Snap Bean.

Halo blight, caused by Pseudomonas syringae pv. phaseolicola, is one of the major bacterial diseases on snap bean in Florida, and the outbreaks of this disease have occurred more often in recent years. Current management of this disease primarily depends on application of fixed copper-based bactericides but climate change and resistance development in the pathogen populations still cause hardship for management of this disease, especially in south Florida. In this study, nicotinamide adenine dinucleotide (NAD+) was evaluated in the greenhouse for its potential to reduce halo blight on snap bean. When NAD+ at 5 mM was applied by soil drench, foliar spray, or leaf infiltration, NAD+ significantly (P < 0.05) reduced disease severity of halo blight on snap bean compared with the untreated control. When NAD+ was applied by leaf infiltration, among the tested concentrations, NAD+ at 0.5 to 1.0 mM was most effective in decreasing halo blight disease. NAD+ at 2.5 mM applied as a foliar spray in rotation with Kocide 3000 (copper hydroxide) at 0.5 mg/ml further reduced disease severity compared with Kocide 3000 alone. In the in vitro study, no inhibitory effects of NAD+ were detected on the bacterial pathogen P. syringae pv. phaseolicola. Results of real-time PCR showed that the defense-related genes PR1, AZI1, EDS1, SARD1, PDF1.2, and PAL1 were upregulated in the NAD+ treatment. Taken together, these data indicated that NAD+ significantly suppressed halo blight on snap bean, and application of NAD+ has the potential in management of this important disease.

Evaluation of dentinal tubule occlusion and pulp tissue response after using 980-nm diode laser for dentin hypersensitivity treatment.

OBJECTIVES: To evaluate the effectiveness of the 980-nm diode laser for dentinal tubule occlusion, measure the intrapulpal temperature, and investigate the dental pulp response. MATERIALS AND METHODS: The dentinal samples were randomly divided into G1-G7 groups: control; 980-nm laser irradiation (0.5 W, 10 s; 0.5 W, 10 s × 2; 0.8 W, 10 s; 0.8 W, 10 s × 2; 1.0 W, 10 s; 1.0 W, 10 s × 2). The dentin discs were applied for laser irradiation and analyzed by scanning electron microscopy (SEM). The intrapulpal temperature was measured on the 1.0-mm and 2.0-mm thickness samples, and then divided into G2-G7 groups according to laser irradiation. Moreover, forty Sprague Dawley rats were randomly divided into the laser-irradiated group (euthanized at 1, 7, and 14 days after irradiation) and the control group (non-irradiated). qRT-PCR, histomorphology, and immunohistochemistry analysis were employed to evaluate the response of dental pulp. RESULTS: SEM indicated the occluding ratio of dentinal tubules in the G5 (0.8 W, 10 s × 2) and G7 (1.0 W, 10 s × 2) were significantly higher than the other groups (p < 0.05). The maximum intrapulpal temperature rises in the G5 were lower than the standard line (5.5 ℃). qRT-PCR showed that the mRNA expression level of TNF-α and HSP-70 upregulated significantly at 1 day (p < 0.05). Histomorphology and immunohistochemistry analysis showed that, compared with the control group, the inflammatory reaction was slightly higher at the 1 and 7 days (p < 0.05) and decreased to the normal levels at 14 days (p > 0.05). CONCLUSIONS: A 980-nm laser at a power of 0.8 W with 10 s × 2 defines the best treatment for dentin hypersensitivity in terms of compromise between the efficacy of the treatment and the safety of the pulp. CLINICAL RELEVANCE: The 980-nm laser is an effective option for treating dentin sensitivity. However, we need to ensure the safety of the pulp during laser irradiation.

Combined effects of hydrothermally-altered feldspar and water regime on cadmium minimization in rice.

The accumulation of cadmium (Cd) in grains and edible parts of crops poses a risk to human health. Because rice is the staple food of more than half of the world population, reducing Cd uptake by rice is critical for food safety. HydroPotash (HYP), an innovative potassium fertilizer produced with a hydrothermal process, has the characteristics of immobilizing heavy metals and potential use for remediating Cd-contaminated soils. The objective of this study was to evaluate the HYP as a soil amendment to immobilize Cd in acidic soils and to reduce the accumulation of Cd in rice tissues. The experiment was performed in a greenhouse with a Cecil sandy loam soil (pH 5.3 and spiked with 3 mg Cd kg-1) under either flooding conditions (water level at 4 cm above the soil surface) or at field capacity. Two hydrothermal materials (HYP-1 and HYP-2) were compared with K-feldspar + Ca(OH)2 (the raw material used for producing HYP), Ca(OH)2, zeolite, and a control (without amendment). After 30 days of soil incubation, HydroPotashs, the raw material, and Ca(OH)2 increased both soil solution pH and electrical conductivity. These materials also decreased soluble Cd concentration (up to 99.7%) compared with the control (p < 0.05). After 145 days, regardless of the materials applied, plant growth was favored (up to 35.8%) under the flooded regime. HydroPotash-1 was more effective for increasing dry biomass compared with other amendments under both water regimes. HydroPotashs reduced extractable Cd in soil, Cd content in plant biomass at tillering and maturing stage, and were efficient in minimizing Cd accumulation in rice grains.

Positional Changes of Mandibular Canal Before and After Decompression of Cystic Lesions in the Mandible.

PURPOSE: Significant displacement of the mandibular canal (MC), which occurs frequently in extensive mandibular cystic lesion cases, may raise the risk of inferior alveolar neurovascular bundle injury in surgery. The aim of the present study was to measure the association between positional changes of the MC and the direction (in the coronal plane) of bone expansion of cystic lesions in the mandible. PATIENTS AND METHODS: We performed a retrospective study of patients who had undergone decompression and enucleation surgery from January 2014 to December 2018. Based on coronal planes of cone-beam computerized tomography, the centroids of the expanded mandibles were calculated and considered markers for evaluation of the directions of bone expansion. In addition, the changes in the position of the MC before decompression and enucleation were measured and compared. A Cartesian coordinate system was introduced in this study to illustrate the relationship of positional changes between the displacement of the MC and expansion of the mandible in a straightforward manner. Statistical analysis was performed using the paired t test, unpaired t test, one-way analysis of variance or linear regression as appropriate. RESULTS: Thirty-six patients with an average age of 29.8 years (14 men, 22 women) who received treatment of decompression and enucleation for mandibular cystic lesions were included in this study. The MCs were displaced in the direction toward the lower edge of the mandible and opposite to the direction of mandibular expansion. In addition, the MCs were relocated close to their original location by 1.67 ± 1.45 mm (mean ± standard deviation) approximately 1 year after decompression, accounting for 22.66% of the total displacement. CONCLUSIONS: In mandibular cystic lesion cases, the MCs tend to displace opposite to the direction of mandibular expansion and relocate less after decompression.

Hydrothermally-altered feldspar as an environmentally-friendly technology to promote heavy metals immobilization: Batch studies and application in smelting-affected soils.

Hydrothermally-altered feldspar (HydroPotash, HYP) possesses, among other physicochemical properties, high pH buffering and cation exchange capacity. Therefore, it may potentially remove heavy metals from aqueous solutions and immobilize these metals in contaminated soil. This study aimed to evaluate the capabilities of two types of HydroPotash (HYP-1 and HYP-2) and a zeolite sample (a commercial adsorbent) for immobilizing cadmium (Cd), zinc (Zn), and lead (Pb) from both aqueous solution and contaminated soils from a Zn-smelting area (classified as soilhigh, soilintermediate, and soillow based on their level of soluble metal concentration). Sorption studies in natural suspension pH showed that HYPs removed 63.8-99.9% Zn, 20.6-40.7% Cd, and 68.4-99.7% Pb from aqueous solution. In the batch test with controlled pH (at pH 5.5), HYPs sorbed more Cd than zeolite. Analyses of scanning electron microscopy-energy dispersive X-ray spectroscopy after desorption showed the presence of Pb at HYP-2, indicating that this metal was effectively adsorbed. In soilhigh HYPs immobilized 99.9% of Zn, Cd, and Pb after one week of soil incubation with these products. The HYPs immobilization effect persisted up to 84 days of soil incubation with these products. The increased soil pH promoted by HYPs appears to be the main factor controlling metal sorption. In conclusion, HydroPotash can be used as an adsorbent/amendment to effectively immobilize heavy metals in both water and contaminated soils by precipitation and adsorption. Our findings indicate the high potential of this material for Cd, Zn, and Pb stabilization, which is of great relevance when recovering areas affected by mining/smelting activities with multi-element contamination.

Pinewood outperformed bamboo as feedstock to prepare biochar-supported zero-valent iron for Cr6+ reduction.

In this work, pinewood and bamboo were pyrolyzed at 600 °C to prepare PBC and BBC-supported zerovalent iron (ZVI), respectively. Raman spectra suggested PBC was more intensively carbonized than BBC as indicated by higher ID/IG ratio. XRD and TEM confirmed nanoscaled ZVI was well dispersed in PBC but soldered in chain-structure in BBC. Maximal chromate (Cr(VI)) sorption capacity followed the order of PBC/ZVI (5.93 g kg-1)>BBC/ZVI (3.61 g kg-1)>BBC (3.55 g kg-1)>PBC (2.59 g kg-1). Desorption and XPS of four Cr-spent sorbents suggested reduction accounted for 79-88% of overall Cr(VI) detoxification. Greater Cr(VI) reduction of BBC than PBC indicated greater tendency of BBC to donate electrons. However, Cr(VI) reduction by PBC/ZVI was 1.7 times greater than BBC/ZVI, corresponding to greater electron transfer of PBC/ZVI (2.5 µA e-) than BBC/ZVI (0.5 µA e-). Thus, PBC is more conducible to transfer electrons as evidenced by Tafel and Amperometric analyses. Demineralization of pristine BC enhanced the difference between PBC/ZVI and BBC/ZVI regarding Cr(VI) reduction, suggesting the dominant role of biopolymers in biomass in terms of electron transfer capacity. Three model biopolymers were compared which indicated lignin-BC had lower electron transfer rates than cellulose-BC and hemicellulose-BC. BC prepared by lignin extracted from pinewood exhibited higher corrosion rate and lower electrical resistance than that from bamboo. Thus, unfavorable lignin in bamboo compromised electron transfer of BBC and Cr(VI) reduction by BBC/ZVI.

Distribution, accumulation, and potential risks of heavy metals in soil and tea leaves from geologically different plantations.

Risk assessment regarding heavy metals in tea is crucial to ensure the health of tea customers. However, the effects of geological difference on distribution of heavy metals in soils and their accumulation in tea leaves remain unclear. This study aimed to estimate the impacts of geological difference on distribution of cadmium (Cd), lead (Pb), thallium (Tl), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), nickel (Ni), and manganese (Mn) in soils and their accumulation in tea leaves, and further evaluate their health risks. 22 soils and corresponding young tea leaves (YTL) and old tea leaves (OTL), from geologically different plantations, were sampled and analyzed. Results showed that heavy metals concentrations in soils, derived from Permian limestone and Cambrian weakly mineralized dolomite, were obviously greater than those from Silurian clastic rock. The geological difference controlled the distribution of soil heavy metals to a large extent. Contents of Cd, Tl, and Mn in tea leaves mainly depended on their contents in soils. Soil Hg, Pb, As, and Sb contents may not be the only influencing factors for their respective accumulation in tea leaves. More attentions should be paid to soil acidification of tea plantations to ensure the tea quality security. Target hazard quotients (THQ) of Cd, Pb, Tl, Hg, As, Sb, Cr, and Ni and hazard index (HI) via tea intake were below one, indicating no human health risk. The non-mineralized Silurian area was less at risk of heavy metals accumulation in tea leaves than the Cambrian metallogenic belt and the Permian Cd-enriched zone. This study could provide an important basis to understand and mitigate the potential risks of heavy metals in tea.

Effect of Wheat-Solanum nigrum L. intercropping on Cd accumulation by plants and soil bacterial community under Cd contaminated soil.

Using accumulators for intercropping in agricultural production can change the heavy metal concentration in the target plants. This study aims to investigate how intercropping wheat (Triticum aestivum L.) and Solanum nigrum L. affects soil bacterial community and cadmium (Cd) absorption in response to Cd-contaminated soil. We compared the concentrations and accumulations of Cd by plants, the activities of soil enzymes and the bacterial community structures of rhizosphere soil in monoculture and intercropping system. Principal component analysis (PCA) ordinations showed that soil bacterial communities were significantly separated by MW and IW, which illustrated intercropping with Solanum nigrum L. impacted the bacterial community structure of wheat. Firstly, the results showed that the biomass of shoots and roots in intercropped wheat (IW) were significantly decreased by 16.19% and 29.38% compared with monoculture wheat (MW) after 60 days after transplanting (DAT). Secondly, the Cd concentration and accumulation of shoots in IW was higher than MW. The Cd accumulation of IW shoots and roots were increased 12.87% and 0.98%, respectively after 60 days DAT. Besides, the enzymes activity [catalase (CAT), urease (UA) and alkaline phosphatase (ALP)] of IW were decreased 35%, 6% and 21%, respectively after 60 days DAT. Finally, the diversity indexes [Abundance-based Coverage Estimator (ACE), Chao and InvSimpson] of IW were lower than MW. These results indicated that intercropping with Solanum nigrum L. inhibited the wheat growth and decreased the bacterial community diversity in wheat rhizosphere, increased the Cd concentration and accumulation in plant tissues of wheat. Therefore, intercropping Solanum nigrum L. and wheat with Cd-contaminated soil might increase the risk of excessive Cd in wheat.

Use of mineral multi-elemental analysis to authenticate geographical origin of different cultivars of tea in Guizhou, China.

BACKGROUND: The geographical origin of tea (Camellia sinensis) can be traced using mineral elements in its leaves as fingerprints. However, the role that could be played by soil mineral elements in the geographical authentication of tea leaves has been unclear. In this study, 22 mineral elements in 73 pairs of tea leaves and soils from three regions (Pu'an, Duyun, and Liping) in Guizhou, China, were determined using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The mineral element concentrations were processed by multivariate statistical analysis, including one-way analysis of variance (ANOVA), correlation analysis, principal component analysis (PCA), and stepwise linear discriminant analysis (S-LDA). RESULTS: Based on a one-way ANOVA, tea leaves and soils with different origins possessed unique mineral element fingerprints. Sixteen mineral element concentrations in tea leaves were significantly correlated with those in soils (P < 0.05). The geographical origins of tea leaves were effectively differentiated using the 16 correlated mineral elements combined with PCA. The S-LDA model offered a 100% differentiation rate, and six indicative elements (phosphorus, Sr, U, Pb, Cd, and Cr) were selected as important fingerprinting markers for the geographic traceability of tea leaves. The accurate discrimination rate of geographical origin was unaffected by the cultivars of tea in the S-LDA model. CONCLUSIONS: Mineral elements in soils played an important role in the geographical authentication of tea leaves. Mineral elemental concentrations with significant correlations between tea leaves and soils could be robust, and could be used to trace the geographical origins of tea leaves. © 2020 Society of Chemical Industry.

Molecular Composition of Size-Fractionated Fulvic Acid-Like Substances Extracted from Spent Cooking Liquor and Its Relationship with Biological Activity.

The treatment of spent cooking liquor is critical for clean production of pulp and paper industry. There is a compelling need to develop a cost-effective and green technology for reuse of organic matter in spent cooking liquor to mitigate the negative impacts on the environment. The objective of this study is to examine the chemical structure of fulvic acid-like substances extracted from spent cooking liquor (PFA) and their relationship with bioactivity in plant growth. Compared with the benchmark Pahokee peat fulvic acid (PPFA), PFA has less aromatic structure, but higher content of lignin, carbohydrates, and amino acid. After fractionation, protein/amino proportion decreased with increasing molecular weight, but the aromaticity increased. Under salt stress, rice seedling growth was promoted by PFA with low molecular weight (<5 kDa), but inhibited by fraction with high molecular weight (>10 kDa). Principal component analysis suggested that promoted growth was more related with chemical structure (O- and N-alkyl moieties) than with molecular weight. This study provided the theoretical basis for development of an innovative green technology of sustainable reuse of spent cooking liquor in agriculture.

Controlled-release urea reduced nitrogen leaching and improved nitrogen use efficiency and yield of direct-seeded rice.

The use of controlled-release urea (CRU) has become one of best management practices for increasing crop yield and improving nitrogen (N) use efficiency (NUE). However, the effects of CRU on direct-seeded rice are not well understood while direct-seeding has gradually replaced transplanting due to increasing labor cost and lack of irrigation water. The objective of this two-year field experiment was to compare the effects of the CRU at four rates (120, 180, 240 and 360 kg N ha-1, CRU1, CRU2, CRU3 and CRU4, respectively) with a conventional urea fertilizer (360 kg N ha-1; U) and a control (no N fertilizer applied; CK) on yield, biomass, NUE of direct-seeded rice and soil nutrients. The results indicated that the successive release rates of N from CRU corresponded well to the N requirements of rice. The use of CRU3 and CRU4 increased rice grain yields by 20.8 and 28.7%, respectively, compared with U. In addition, the NUEs were improved by all CRU treatments compared to the U treatment. Concentrations of NO3--N and NH4+-N in the soil were increased, especially during the later growth stages of the rice, and the leaching of N was reduced with CRU treatments. In conclusion, applying CRU on direct-seeded rice increased the crops yields and NUE, increased nitrogen availability at the late growth stages, and reduced N leaching.

Multielemental Analysis Associated with Chemometric Techniques for Geographical Origin Discrimination of Tea Leaves (Camelia sinensis) in Guizhou Province, SW China.

This study aimed to construct objective and accurate geographical discriminant models for tea leaves based on multielement concentrations in combination with chemometrics tools. Forty mineral elements in 87 tea samples from three growing regions in Guizhou Province (China), namely Meitan and Fenggang (MTFG), Anshun (AS) and Leishan (LS) were analyzed. Chemometrics evaluations were conducted using a one-way analysis of variance (ANOVA), principal component analysis (PCA), linear discriminant analysis (LDA), and orthogonal partial least squares discriminant analysis (OPLS-DA). The results showed that the concentrations of the 28 elements were significantly different among the three regions (p < 0.05). The correct classification rates for the 87 tea samples were 98.9% for LDA and 100% for OPLS-DA. The variable importance in the projection (VIP) values ranged between 1.01⁻1.73 for 11 elements (Sb, Pb, K, As, S, Bi, U, P, Ca, Na, and Cr), which can be used as important indicators for geographical origin identification of tea samples. In conclusion, multielement analysis coupled with chemometrics can be useful for geographical origin identification of tea leaves.

An HPLC method for simultaneous quantitative determination of seven secoiridoid glucosides separated from the roots of Ilex pubescens.

A simple and specific high-performance liquid chromatographic method has been developed and validated to simultaneously determine seven secoiridoid glucosides for the first time. Three of them were separated from the ethanolic extract of the roots of Ilex pubescens for the first time, namely nuezhenide A, ligusides B and oleonuezhenide. In quantitative analysis, all of the calibration curves showed good linear regression (r > 0.999) within the tested ranges, and the mean recoveries of three different concentrations ranged from 97.6 to 101.2%. The limit of detection and limit of quantification were <4.18 and 11.63 ng mL-1 , respectively. The relative standard deviation for repeatability and the precision of seven analytes were <3.4 and 1.9%, respectively. The established method was successfully applied to simultaneous determination of seven secoiridoid glucosides in 11 batches of samples collected from different habitats in China.

Linking Spatial Variations in Water Quality with Water and Land Management using Multivariate Techniques.

Most studies using multivariate techniques for pollution source evaluation are conducted in free-flowing rivers with distinct point and nonpoint sources. This study expanded on previous research to a managed "canal" system discharging into the Indian River Lagoon, Florida, where water and land management is the single most important anthropogenic factor influencing water quality. Hydrometric and land use data of four drainage basins were uniquely integrated into the analysis of 25 yr of monthly water quality data collected at seven stations to determine the impact of water and land management on the spatial variability of water quality. Cluster analysis (CA) classified seven monitoring stations into four groups (CA groups). All water quality parameters identified by discriminant analysis showed distinct spatial patterns among the four CA groups. Two-step principal component analysis/factor analysis (PCA/FA) was conducted with (i) water quality data alone and (ii) water quality data in conjunction with rainfall, flow, and land use data. The results indicated that PCA/FA of water quality data alone was unable to identify factors associated with management activities. The addition of hydrometric and land use data into PCA/FA revealed close associations of nutrients and color with land management and storm-water retention in pasture and citrus lands; total suspended solids, turbidity, and NO + NO with flow and Lake Okeechobee releases; specific conductivity with supplemental irrigation supply; and dissolved O with wetland preservation. The practical implication emphasizes the importance of basin-specific land and water management for ongoing pollutant loading reduction and ecosystem restoration programs.

Seawater flooding of calcareous soils: Implications for trace and alkaline metals mobility.

Developing management strategies to safeguard public health and environmental sustainability requires a comprehensive understanding of the solubility and mobility of trace and alkaline metals in the event of seawater flooding. This study investigated the effects of seawater flooding, along the duration of flooding, on the release of trace and alkaline metals (Mn, Fe, Cu, Zn, Ca, K, and Mg) in two calcareous soils (Krome and Biscayne) located in southern Florida. Seawater flooding experiments involved two soil types and four flooding durations (1, 7, 14, and 28 days) replicated three times. Freshwater flooding experiments were also conducted for comparison. After each flooding experiment, soil samples were collected at three depths (15, 30, and 45 cm), and analyzed for selected elements. Comparative analysis revealed significant releases of Mn, Fe, and Zn in both soils flooded by seawater compared to freshwater. In most cases, significant increments were evident as early as 1-day exposure to seawater flooding, which further increased with flooding duration. However, the impacts of seawater flooding had notable differences between the two soils. Seawater flooding in Krome soil for 28 days, resulted in higher Mn, Fe, and Zn contents by 58, 340, and 510% compared with freshwater flooding, while corresponding increases in Biscayne soil were 3.3, 130, and 180%, respectively. Comparable marginal increases in Cu content were observed for both soils. Similarly, seawater flooding increased K, Mg, and Na contents from single-day flooding. The interplay between soil type, column depth, flooding duration, and their interactions proved influential factors in determining Mn, Fe, Cu, and Zn releases, with peak levels typically observed on the 28th day of flooding and at bottom depths. Overall, these findings highlight the release of these elements, raising concerns about potential plant toxicity and groundwater or surface water contamination due to leaching and runoff.

A switch in the pathway of TRPC3-mediated calcium influx into brain pericytes contributes to capillary spasms after subarachnoid hemorrhage.

Calcium influx and subsequent elevation of the intracellular calcium concentration ([Ca2+]i) induce contractions of brain pericytes and capillary spasms following subarachnoid hemorrhage. This calcium influx is exerted through cation channels. However, the specific calcium influx pathways in brain pericytes after subarachnoid hemorrhage remain unknown. Transient receptor potential canonical 3 (TRPC3) is the most abundant cation channel potentially involved in calcium influx into brain pericytes and is involved in calcium influx into other cell types either via store-operated calcium entry (SOCE) or receptor-operated calcium entry (ROCE). Therefore, we hypothesized that TRPC3 is associated with [Ca2+]i elevation in brain pericytes, potentially mediating brain pericyte contraction and capillary spasms after subarachnoid hemorrhage. In this study, we isolated rat brain pericytes and demonstrated increased TRPC3 expression and its currents in brain pericytes after subarachnoid hemorrhage. Calcium imaging of brain pericytes revealed that changes in TRPC3 expression mediated a switch from SOCE-dominant to ROCE-dominant calcium influx after subarachnoid hemorrhage, resulting in significantly higher [Ca2+]i levels after SAH. TRPC3 activity in brain pericytes also contributed to capillary spasms and reduction in cerebral blood flow in an in vivo rat model of subarachnoid hemorrhage. Therefore, we suggest that the switch in TRPC3-mediated calcium influx pathways plays a crucial role in the [Ca2+]i elevation in brain pericytes after subarachnoid hemorrhage, ultimately leading to capillary spasms and a reduction in cerebral blood flow.

A novel mussel-inspired desensitizer based on radial mesoporous bioactive nanoglass for the treatment of dentin exposure: An in vitro study.

OBJECTIVES: The dentin exposure always leads to dentin hypersensitivity and the acid-resistant/abrasion-resistant stability of current therapeutic approaches remain unsatisfatory. Inspired by the excellent self-polymerization/adherence activity of mussels and the superior mineralization ability of bioactive glass, a novel radial mesoporous bioactive nanoglass coated with polydopamine (RMBG@PDA) was developed for prevention and management of dentin hypersensitivity. METHODS: Radial mesoporous bioactive nanoglass (RMBG) was synthesized by the sol-gel process combined with the cetylpyridine bromide template self-assembly technique. RMBG@PDA was synthesized by a self-polymerization process involving dopamine and RMBG in an alkaline environment. Then, the nanoscale morphology, chemical structure, crystalline phase and Zeta potential of RMBG and RMBG@PDA were characterized. Subsequently, the ion release ability, bioactivity, and cytotoxicity of RMBG and RMBG@PDA in vitro were investigated. Moreover, an in vitro experimental model of dentin hypersensitivity was constructed to evaluate the effectiveness of RMBG@PDA on dentinal tubule occlusion, including resistances against acid and abrasion. Finally, the Young's modulus and nanohardness of acid-etched dentin were also detected after RMBG@PDA treatment. RESULTS: RMBG@PDA showed a typical nanoscale morphology and noncrystalline structure. The use of RMBG@PDA on the dentin surface could effectively occlude dentinal tubules, reduce dentin permeability and achieve excellent acid- and abrasion-resistant stability. Furthermore, RMBG@PDA with excellent cytocompatibility held the capability to recover the Young's modulus and nanohardness of acid-etched dentin. CONCLUSION: The application of RMBG@PDA with superior dentin tubule occlusion ability and acid/abrasion-resistant stability can provide a therapeutic strategy for the prevention and the management of dentin hypersensitivity.

Novel pit and fissure sealant with nano-CaF2 and antibacterial monomer: Fluoride recharge, microleakage, sealing ability and cytotoxicity.

Conventional resin-based sealants release minimal fluoride ions (F) and lack antibacterial activity. The objectives of this study were to: (1) develop a novel bioactive sealant containing calcium fluoride nanoparticles (nCaF2) and antibacterial dimethylaminohexadecyl methacrylate (DMAHDM), and (2) investigate mechanical performance, F recharge and re-release, microleakage, sealing ability and cytotoxicity. Helioseal F served as commercial control. The initial F release from sealant containing 20% nCaF2 was 25-fold that of Helioseal F. After ion exhaustion and recharge, the F re-release from bioactive sealant did not decrease with increasing number of recharge and re-release cycles. Elastic modulus of new bioactive sealant was 44% higher than Helioseal F. The new sealant had excellent sealing, minimal microleakage, and good cytocompatibility. Hence, the nanostructured sealant had substantial and sustained F release and antibacterial activity, good sealing ability and biocompatibility. The novel bioactive nCaF2 sealant is promising to provide long-term F ions for caries prevention.

Mechanistic investigation of mercury sorption by Brazilian pepper biochars of different pyrolytic temperatures based on X-ray photoelectron spectroscopy and flow calorimetry.

We investigated the mechanisms of Hg sorption onto biochars produced from Brazilian pepper (BP; Schinus terebinthifolius) at 300, 450, and 600 °C using different analytical techniques. The Hg sorption capacity of BP300, BP450, and BP600 was 24.2, 18.8, and 15.1 mg g(-1) based on Langmuir isotherm. FTIR data suggested the participation of phenolic hydroxyl and carboxylic groups in Hg sorption by biochars. XPS analysis showed that 23-31% and 77-69% of sorbed Hg was associated with carboxylic and phenolic hydroxyl groups in biochars BP300-450, whereas 91% of sorbed Hg was associated with a graphite-like domain on an aromatic structure in BP600 biochar, which were consistent with flow calorimetry data. Based on flow calorimetry, sorption of K and Ca onto biochar was exchangeable with the molar heat of sorption of 3.1 kJ mol(-1). By comparison, Hg sorption was via complexation with functional groups as it was not exchangeable by K or Ca with molar heat of sorption of -19.7, -18.3, and -25.4 kJ mol(-1) for BP300, BP450, and BP600. Our research suggested that Hg was irreversibly sorbed via complexation with phenolic hydroxyl and carboxylic groups in low temperature biochars (BP300 and BP450) and graphite-like structure in high temperature biochar (BP600).

Controlled-release urea commingled with rice seeds reduced emission of ammonia and nitrous oxide in rice paddy soil.

Reduction of ammonia (NH) and nitrous oxide (NO) emission and enhanced nitrogen (N) fertilizer use efficiency have been investigated with different N fertilizer management and application methods for irrigated rice production. Few studies have examined NH and NO emissions from rice paddy soil when commingling controlled release urea with rice seeds. The objective of this study was to assess NH volatilization and NO emission from a novel controlled-release urea formulation (CRU-180) when commingled at the full application rate with seeds in a single application during the preparation of plant plugs at the nursery stage. The experiment was conducted as a factorial design with two fertilizer sources (conventional urea and CRU-180), four rates (0, 100, 200, and 300 kg N ha), and three replicates. The entire amount of CRU-180 was incorporated into each plug with germinated seed. The conventional urea was split into four applications based on the standard practice for fertilizer application. The CRU-180 treatments reduced the NH and NO concentration in the paddy flood water and paddy soil solution as compared with the conventional urea treatments. The percentage of applied N fertilizer emitted as NH volatilization and NO emission in the CRU-180 treatments was only about 10% of that from the conventional urea treatments at the same N application rate. The application of CRU-180 with seeds offers a novel N fertilizer management technique, a method to reduce environmental impacts associated with rice production and the cost of rice production.