Enhancement in Seed Priming-Induced Starch Degradation of Rice Seed Under Chilling Stress via GA-Mediated α-Amylase Expression.

Chilling stress is the major abiotic stress that severely limited the seedling establishment of direct-seeded rice in temperate and sub-tropical rice production regions. While seed priming is an efficient pre-sowing seed treatment in enhancing crop establishment under abiotic stress. Our previous research has identified two seed priming treatments, selenium priming (Se) and salicylic priming (SA) that effectively improved the seed germination and seedling growth of rice under chilling stress. To further explore how seed priming enhance the starch degradation of rice seeds under chilling stress, the present study evaluated the effects of Se and SA priming on germination and seedling growth, α-amylase activity, total soluble sugar content, hormone content and associated gene relative expression under chilling stress. The results showed that both Se and SA priming significantly increased the seed germination and seedling growth attributes, and enhanced the starch degradation ability by increasing α-amylase activity and total soluble sugar content under chilling stress. Meanwhile, seed priming increased the transcription level of OsRamy1A, OsRamy3B that regulated by GA, and increased the transcription level of OsRamy3E that regulated by sugar signals. Furthermore, seed priming significantly improved the GA3 contents in rice seeds by up-regulating the expression of OsGA3ox1 and OsGA20ox1, and decreased the ABA content and the expression of OsNCED1, indicating that the improved starch degradation ability in primed rice seeds under chilling stress might be attributed to the increased GA3 and decreased ABA levels in primed rice seeds, which induced the expression of GA-mediated α-amylase. However, studies to explore how seed priming mediate hormonal metabolism and the expression of OsRamy3E are desperately needed.

Long-term performance of a full-scale intermittently decanted extended aeration (IDEA) plant: The effect of dissolved oxygen and the relocation of alum dosing to bioselector.

Dosing alum to remove phosphorus (P) from wastewater is a common practice. However, the dosing-location and quantity of alum required to meet P discharge limits are vaguely defined. As such, utilities overdose alum to avoid noncompliance, but this leads to wastage and costs. This study aimed to address this issue through a long-term evaluation of an alum-assisted full-scale intermittently decanted extended aeration (IDEA) plant. Specifically, the effects of relocating alum dosing from a low P containing IDEA-tank to a bioselector containing elevated P concentrations were examined. The plant is fitted with two IDEA-tanks, each retrofitted with a bioselector at the inlet end. Over 359 d, key parameters (dissolved oxygen (DO), NH4+-N, NO2--N, NO3--N, PO43--P) were quantified to account for the effects of switching alum-dosing into the bioselector and varying dosages (429, 643, 1072 and 1286 g-Al3+ per treatment cycle). Results indicated a 52% reduction of alum usage with no impact on discharge limit (≤0.85 mg-P/L). As expected, a failure to maintain DO setpoint (1.6 mg/L) reduced both NH4+-N and PO43--P removal. Increasing alum dosage simply could not alleviate this problem, but maintenance of DO at least 85% of setpoint enabled effective rectification. This 15% DO buffer zone offers operators an opportunity to rectify imminent operational failures related to DO, prior to escalating alum dosage. An operational framework to manage DO related failures is proposed. Overall, this study offers insights on how to cost effectively apply alum and manage DO failures to achieve P discharge limits in IDEA plants.

Sequential removal of selenate, nitrate and sulfate and recovery of elemental selenium in a multi-stage bioreactor process with redox potential feedback control.

Bioreduction can facilitate oxyanions removal from wastewater. However, simultaneously removing selenate, nitrate and sulfate and recovering high-purity elemental selenium (Se0) from wastewater by a single system is difficult and may lead to carcinogenic selenium monosulfide (SeS) formation. To solve this issue, a two-stage biological fluidized bed (FBR) process with ethanol dosing based on oxidation-reduction potential (ORP) feedback control was developed in this study. FBR1 performance was first evaluated at various ORP setpoints (between -520 and -360 mV vs. Ag/AgCl) and elevated sulfate concentration. Subsequently, ethanol-fed FBR2 was used to reduce sulfate from FBR1 effluent, followed by an aerated sulfide oxidation reactor (SOR). At - 520 mV≤ ORPs≤ -480 mV, FBR1 removed 100 ±â€¯0.1% nitrate and 99.7 ±â€¯0.3% selenate without sulfate reduction. At ORPs ≥ -440 mV, selenate reduction was incomplete, whereas nitrate removal remained stable. Se0 recovery efficiency from FBR1 effluent was 37.5% with 71% Se purity. FBR2 converted 86% of the remaining sulfate in FBR1 effluent to hydrogen sulfide, but the over-oxidation of dissolved sulfide in SOR decreased the overall sulfate removal efficiency to ~46.3%. Overall, the two-stage FBR process with ORP feedback dosing of ethanol was effective for sequentially removing selenate, nitrate and sulfate and recovering Se0 from wastewater.

Magnetoelectric effect in flexible nanocomposite films based on size-matching.

Flexible magnetoelectric (ME) nanocomposites with a strong coupling between ferromagnetism and ferroelectricity are of significant importance from the point of view of next-generation flexible electronic devices. However, a high loading of magnetic nanomaterials is needed to achieve preferable ME response due to the size mismatch of the magnetostrictive phase and piezoelectric phase. In this work, ultra-small CoFe2O4 nanoparticles were prepared to match the size of the polar crystal in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) is introduced to enhance the interplay between P(VDF-TrFE) and CoFe2O4. The above multiple effects promote a good connection between the magnetostrictive phase and the piezoelectric phase. Therefore, an effective transference of stress from CoFe2O4 to P(VDF-TrFE) can be achieved. The as-prepared P(VDF-TrFE)/CoFe2O4@POTS exhibits a high ME coupling coefficient of 34 mV cm-1 Oe-1 when the content of CoFe2O4@POTS is 20 wt%. The low loading of fillers ensures the flexibility of ME nanocomposite films.

Insights drawn from a full-scale Intermittently Decanted Extended Aeration (IDEA) plant for optimising nitrogen and phosphorus removal from municipal wastewater.

Intermittently Decanted Extended Aeration (IDEA) processes are widely used for wastewater treatment. However, in-depth performance evaluation of a full-scale IDEA plant is rare, making it challenging for water utilities to meet the increasingly stringent discharge requirements with these assets. This study aims to fill this gap through a comprehensive assessment of nitrogen and phosphorus removal in a full-scale IDEA plant in Australia. The plant consists of two identical IDEA tanks operated in-parallel. Upstream to each tank is a bioselector with four interlinked compartments. We conducted an eight-week monitoring program with four intensive cyclic studies to establish detailed nutrient profiles of the two IDEA tanks to assess the performance of nitrogen and alum assisted phosphorus removal. Results showed that the plant enabled good nitrification in the IDEA effluent. However, the denitrification efficiency was low (ca. 50%), and could be improved by decreasing oxygen supply to suppress nitrite oxidation and preserve influent carbon. The addition of alum to the IDEA tank appeared to be ineffective given the low P concentration (<1 mg-P/L) in the tank. The bioselector was identified as a better alum-dosing location, given its higher (~7-fold) phosphate concentration in comparison to the influent. Stopping the dosing of alum only marginally increased the effluent P (0.35 to 0.52 mg-P/L), implying that P removal was predominantly (94%) biologically mediated and achieved via P accumulating microorganisms. Overall, this study offers timely and useful process understanding of the performance of IDEA plants, as well as other similar wastewater treatment configurations.

Natural Microtubule-Encapsulated Phase-Change Material with Simultaneously High Latent Heat Capacity and Enhanced Thermal Conductivity.

It is of critical importance to exploit high-performance phase-change materials (PCM) for thermal energy storage. Present form-stable PCM suffer from the defects in low PCM loading, poor form stability, low thermal conductivity, and complicated approaches. We prepared a novel microtubule-encapsulated phase-change material (MTPCM) by encapsulating lauric acid (LA) into kapok fiber (KF) microtubules that had been precoated with silver nanoparticles. The measured melting and freezing temperatures were 43.9 and 41.3 °C for the LA/KF MTPCM and 44.1 and 42.1 °C for the LA/KF@Ag MTPCM, respectively. After being heated, the MTPCM can retain its original solid state without leaking, even under a pressure of 500 times the gravity of MTPCM itself, which shows that the encapsulated phase-change material can undergo a solid-liquid transition microscopically while retaining its macroscopic solid state. The latent heats of fusion were found to be 153.5 J/g for the LA/KF MTPCM and 146.8 J/g for the LA/KF@Ag MTPCM, which is up to 86.5% and 82.7% that of pristine LA, respectively. This thermal energy storage capacity is much higher than reported values in recent literature, which tend to be ≤60%. In contrast with the penalty of a 3.8% decrease in latent heat capacity, the remarkable 92.3% increase in thermal conductivity caused by the introduction of silver nanoparticles is more pronounced. The thermoregulatory capacity analysis results show that the thermal transfer efficiency of LA/KF@Ag MTPCM has been enhanced significantly by 15.8% and 23.5% in terms of thermal energy storage and release compared to that of the LA/KF MTPCM. Moreover, the LA/KF@Ag MTPCM exhibits a robust thermal, chemical, and morphological reliability after 2000 thermal cycles, which makes it favorable for repetitive thermal energy storage/retrieval applications. The high latent heat, suitable phase-change temperature, outstanding form stability, robust thermal reliability, enhanced thermal transfer efficiency, and the inherited advantages of KF and nanosilver provide potential for the novel application of MTPCM in solar thermal energy storage, waste heat recovery, intelligent thermoregulated textiles, and infrared stealth of important military targets.

Hydrophilic Magnetofluorescent Nanobowls: Rapid Magnetic Response and Efficient Photoluminescence.

Multifunctional integration based on a single nanostructure is emerging as a promising paradigm to future functional materials. In this paper, novel magnetofluorescence nanobowls built with ferroferric mandrel and quantum dots exoderm is reported. Magnetic mandrels are stacked into nanobowls though hydrophobic primary Fe3O4 nanocrystals dragged into anion polyelectrolyte aqueous solution via forced solvent evaporation. Bright luminescence core/shell/shell CdSe/CdS/ZnS quantum dots (QDs) are modified with cationic hyperbranched polyethylenimine (PEI). Through electrostatic interactions, positively charged PEI-coated QDs are anchored on the surface of magnetic mandrel. Under this method, the luminescence of QDs is not quenched by magnetic partners in the resultant magnetoflurescence nanobowls. Such magnetoflurescence nanobowls exhibit high saturation magnetization, superparamagnetic characteristics at room temperature, superior water dispersibility, and excellent photoluminescence properties. The newly developed magnetoflurescence nanobowls open a new dimension in efforts toward multimodal imaging probes combining strong magnetization and efficient fluorescence in tandem for biosensors and clinical diagnostic imaging.