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L-threo-methylsulonylphenylserine (L-threo-MSPS) is a crucial intermediate in florphenicol and thiamphenicol synthesis. L-threo-MSPS can be synthesized from L-threonine and p-methylsulfonylbenzaldehyde (p-MSBA) chiral selectively under the catalyse of L-threonine transaldolase. However, the byproduct acetaldehyde formed during the reaction process severely hinders the biosynthesis of high-quality L-threo-MSPS. The accumulated acetaldehyde reacts with L-thero-MSPS and L-threonine to form N-derivatives, and the activity of L-threonine transaldolase decreases to 14.10% even when the concentration of acetaldehyde is as low as 0.5 g/L. The acetaldehyde could be removed by aeration, and the removal efficiency is closely related to the aeration conditions, which was described by the volumetric oxygen transfer coefficient k L a in this paper. Regular aeration through pipes cannot provide enough aeration efficiency, and filters or sintered rods were used to increase the k L a value during the reaction. The residual concentration of acetaldehyde depended on the balance between the formation and removal speed of acetaldehyde. When the optimal enzyme concentration was applied and the k L a value of 5.5 min-1, the L-threo-MSPS concentration reached 293.28 mM in a 1-L reaction, and the highest conversion reached 90.03%. The need of coenzyme NAD+ was cut off in this method, and only one enzyme was applied. Consequently, the reaction was simpler and easier to control. [Display omitted] • NAD+-independent biosynthesis of L-threo-MSPS with transaldolase and aeration. • The derivatization of L-threo-MSPS and L-threonine by acetaldehyde in the reaction. • The relation between acetaldehyde removal efficiency and the kLa value of aeration. • Increased conversion of L-threo-MSPS from 60% to 90% by aeration. [ABSTRACT FROM AUTHOR]

Abstract The water and nitrogen recovery from human urine are the crucial issues for the water recycling in the bioregenerative life support system (BLSS). Most of the water in the urine could be recovered through physical/chemical methods, however the efficiency of recovering nitrogen remained unsatisfactory. In our previous work, immobilized urease catalysis followed by reduced pressure distillation has been utilized to purify the urine, and high recovery efficiency of both water and nitrogen has been gained. However, the source of the urease and the immobilization preparation method would limit its practical application. In this study, biological activated carbon (BAC) immobilizing urease-producing microorganisms was explored as the continuous provider of urease to hydrolyze urea existing in human urine. The batch experiment results illustrated that it is feasible to use BAC technology to hydrolyze urea in urine and the highest urea hydrolysis efficiency of 79.33% was gained in synthetic urine with the powder activated carbon dosage (PACD) of 100 g/L and the hydraulic retention time (HRT) of 5 d. Image results of scanning electron microscope and confocal laser scanning microscope presented that BAC succcessfully immobilized living bacteria, and 16S rRNA high throughput sequencing illustrated that the main urease-producing bacteria were genera of Bacillus , Sporosarcina , Pseudomonas and Paracoccus , and genera of Pseudomonas and Paracoccus possessed heterotrophic nitrification ability as well. A pilot-scale membrane biological reactor inoculated with urea-hydrolyzing BAC cultivated in batch experiment was applied to treat the crew's urine continuously inside an experimental facility for BLSS, and the urea hydrolysis efficiency could maintain at 99.84% during 203 d operation. Graphical abstract Image 1 Highlights • Urease-producing bacteria immobilized on BAC were used to hydrolyze urea in urine. • 79.33% of the urea in synthetic urine was hydrolyzed by BAC in optimal conditions. • Living urease-producing bacteria were confirmed to be enriched by BAC. • Membrane-BAC reactor was successfully applied to treat crew's urine in BLSS. [ABSTRACT FROM AUTHOR]

Accurate detecting bacterial communities in ballast water and sediments supports risk management. This study uses full-length 16S rRNA gene sequencing to investigate the bacterial communities in ballast water and sediments, focusing on detecting pathogens. The results indicate that full-length sequencing more accurately reveals the species diversity. There is a significant difference (P < 0.05) in bacterial communities between ballast water and sediments, despite both being dominated by the Proteobacteria phylum. Thirty human and fish pathogens were identified by full-length sequencing, yet only five pathogens were detected from V3-V4 sequencing. Notably, emerging pathogens such as Citrobacter freundii and Nocardia nova are detected in samples, which are harmful to aquaculture and human health. Several opportunistic pathogens were also identified. In summary, this study provides important insights into the bacterial communities in ballast water and sediments, highlighting the need for strict management. [Display omitted] • Full-length 16S rRNA gene sequencing promotes the annotation of bacterial community. • The bacterial community in ballast sediments was richer than in water. • More pathogens were found with the support of full-length gene sequencing. • Several emerging pathogens were detected in the ballast water and sediments. [ABSTRACT FROM AUTHOR]

Eutrophication and hydrodynamics determine the final distribution patterns of aquatic macrophytes; however, there is limited available knowledge regarding their interactive effects. Morphological and biomechanical responses to eutrophication and hydrodynamic stresses were assessed by sampling five abundant and dominant species, Potamogeton maackianus , P. pectinatus , P. lucens , Ceratophyllum demersum and Myriophyllum spicatum , in three macrophyte beds in Lake Erhai, Yunnan Province, China: one exposed to eutrophication and moderate southeast (SE) wind; one with mesotrophication, but sheltered by the lakeshore, with weak wind disturbance; and one with meso-eutrophication and strong SE wind. The results showed significant interactive effects of eutrophication and hydrodynamics on most biomechanical traits and some morphological traits, suggesting that aquatic macrophytes preferentially undergo biomechanical adjustments to resist the coexisting eutrophication and hydrodynamic stresses. In particular, hydrodynamics increased both the tensile force and tensile strain of P. maackianus under meso-eutrophication and dramatically decreased them in eutrophic areas, suggesting that eutrophication triggers mechanical failure in this species. Additionally, P. pectinatus , C. demersum and M. spicatum showed the lowest and highest values for the biomechanical variables (greater values for M. spicatum ) in the most eutrophic and hydrodynamic areas, respectively, implying that increases in hydrodynamics primarily induce mechanical damage in eutrophic species. The plants generally exhibited greater tensile strain in both shallow and deep waters and the greatest tensile force at moderate depths. The stem cross-sectional area, plant height, stem length, internode length, and branch traits were all responsible for determining the biomechanical variables. This study reveals that hydrodynamic changes primarily induce mechanical damage in eutrophic species, whereas eutrophication triggers mechanical damage in sensitive species. [ABSTRACT FROM AUTHOR]

In the bioregenerative life support system (BLSS), water recycling is one of the essential issues. The Lunar Palace 1, a ground-based bioregenerative life support system experimental facility, has been developed by our team and a 105-day closed bioregenerative life support experiment with multi-crew involved has been accomplished within this large-scale facility. During the 105-day experiment, activated carbon-absorption/ultra-filtration, membrane-biological activated carbon reactor and reduced pressure distillation technology have been used to purify the condensate water, sanitary & kitchen wastewater and urine, respectively. The results demonstrated that the combination of those technologies can achieve 100% regeneration of the water inside the Lunar Palace 1. The purified condensate water (the clean water) could meet the standards for drinking water quality in China (GB5749-2006). The treatment capacity of the membrane-biological activated carbon reactor for sanitary & kitchen wastewater could reach 150 kg/d. During the 105-d experiment, the average volume loading of the bioreactor was 0.441 kgCOD/(m 3 d), and the average COD removal efficiency was about 85.3%. The quality of the purified sanitary & kitchen wastewater (the greywater) could meet the standards for irrigation water quality (GB 5084–2005). In addition, during the 105-day experiment, the total excreted urine volume of three crew members was 346 L and the contained water was totally treated and recovered. The removal efficiency of ion from urine was about 88.12%. Moreover, partial nitrogen within the urine was recovered as well and the average recovery ratio was about 20.5%. The study laid a foundation for the water recycling technologies which could be used in BLSS for lunar or Mars bases. [ABSTRACT FROM AUTHOR]

With the growing demand of safety and accurate control for electric vehicles, it is urgent to develop a physics-based electrochemical model of lithium-ion battery with simple calculation and high accuracy over wide temperature range for application in battery management system (BMS). However, traditional electrochemical models are too complex to be applied in real usage, and most of them fail to capture thermal characteristics of the cell. Therefore, a fractional-order model of lithium-ion battery considering polarization in electrolyte and thermal effect (FOMeT) is proposed in this paper. The fractional-order model (FOM) is improved by considering the polarization in electrolyte. The particle thermal model is proposed to describe the heat generation and absorption of the cell. Finally, the FOM considering electrolyte polarization and the particle thermal model are combined to form FOMeT by coupling the cell temperature and dynamics of lithium-ion. The results show that the proposed model performs high voltage accuracy and temperature accuracy over wide temperature range (273.15K∼318.15K) and wide current load range (0.5C∼2C). [ABSTRACT FROM AUTHOR]

Nonetheless, the photovoltaic (PV) system's reliability performance remains a major challenge. The factors that affect the reliability of a PV system include the location of the plant, its environmental conditions, and the type of equipment that it uses. Researchers noted that the performance of a PV inverter is dependent on the environment variations like mission profile. Hence to understand the impact of environmental conditions on the system's performance, mission profile analysis is required. The objective of this study is to perform reliability oriented lifetime assessment of a cascaded H-bridge multilevel inverter (CHMI) considering the mission profile to account for the factors that affect its performance. CHMI consists of a large number of switches and DC-link capacitors which increases the probability of failure. So, a lifetime assessment of CHMI is required. A test case of 3 kW 1-phase CHMI based PV system is considered and modelled in PLECS. To determine the effect of the installation site on the lifetime of the cascaded H-bridge multilevel PV inverter (MLPVI), real-time mission profiles for one-year recorded in South India and Denmark are considered. With this mission profile from installation locations, system-level reliability assessment of MLPVI is carried out based on the loss model and thermal model of the insulated gate bipolar transistors (IGBTs) and DC-link capacitors. The results reveal that environmental conditions have a considerable impact on the reliability performance of PV inverter. • System-level reliability assessment of cascaded H-bridge multilevel PV inverter considering mission profile • The reliability assessment is carried out based on the loss model and thermal model of the IGBTs and DC-link capacitors. • The system-level reliability of the PV inverter has been strongly influenced by the mission profile. [ABSTRACT FROM AUTHOR]

The northeastern continental slope of the South China Sea is one of the promising areas for gas hydrates, which is characterized by its variable topography and complex tectonics. In this paper, two gravity piston cores were sampled from the shallow sediments in the vicinity of the region where various morphologies of gas hydrate was recovered during the second gas hydrate expedition of Guangzhou Marine Geological Survey. Conventionally, the identification of gas hydrate was primarily dependent on the bottom simulating reflector (BSR). Apart from BSR, the anomalies in pore water geochemistry, which are highly related to various microbially-mediated processes and features of fluid from deep hydrocarbon reservoir, are also helpful for the gas hydrate exploration. In this study, upward methane flux may be responsible for distinct characteristics of pore waters observed at the two sample sites. A reactive transport model was accordingly established to compare contrastive fluid features and to estimate the upward methane flux. Since fluid migration is typically associated with complex tectonic settings of the study area, it is proposed that heterogeneous distribution of gas hydrates along the continental margin should be well considered. [ABSTRACT FROM AUTHOR]

Abalone withering syndrome is a serious chronic disease. Ultrastructure and pathological changes were studied using transmission electron microscopy. Myofibers appeared hollow, and the number of inner intact myofibrils was reduced greatly. The morphology of mitochondria in cells appeared abnormal. Crystal lattice-like inclusions in pathological muscle cells were observed. The hepatopancreas was damaged severely; it was full of empty vesicles and devoid of any recognizable cellular structures. The activities of 3 enzymes, acid phosphatase (ACP), alkaline phosphatase (AKP), and total superoxide dismutase (T-SOD), in hemolymph of healthy and diseased abalone showed little differences. ACP activity in the pedal mucus of healthy and diseased abalone was not significantly different. However, in diseased abalone pedal mucus, activities of AKP and T-SOD were significantly lower than in the control group. In pedal mucus of healthy and diseased abalone, the differential (SDS-PAGE) bands were identified as actin and hemocyanin. Protein identification was accomplished with mass spectrometry. A total of 16 2-DE gel spots were identified; 5 gel spots showed upregulation and 11 gel spots showed downregulation in diseased abalone. Proteins involved in energy production and storage, including fructose-1, 6-bisphosphate aldolase, arginine kinase, and triosephosphate isomerase, showed diverse expression patterns in diseased abalone. For stress-responsive proteins, expression of Cu/Zn-superoxide dismutase showed downregulation. For contraction and regulation proteins of muscle, actin showed significant downregulation. Statement of relevance Abalone withering syndrome (WS) is a serious chronic disease. However, there is limited information on the physiological performance of infected abalones. The present study was to assess the alterations of Haliotis diversicolor caused by WS using transmission electron microscopy as well as assess the immune enzyme activity of hemolymph and mucus, and muscle, mucus proteins changes by 2-DE and SDS-PAGE. [ABSTRACT FROM AUTHOR]

Parameterized evaluation of thermal characteristics for a lithium ion battery is a challenge due to the facts: 1) heat generated by a battery is extremely hard to be measured; 2) the measured surface temperature is unable to reflect the entire thermal status. In this study, thermal energy conversion efficiency is proposed to evaluate the thermal behaviors. Results show thermal energy conversion efficiencies at 2 C are about 4.6% and 8.1% when charging and discharging, respectively, showing the former is significantly less than the later. The elevated temperature also shows the similar trend. The increased max temperatures at 2 C are about 16 K and 30 K when charging and discharging, respectively. It is found that the irreversible thermal energy is higher when discharging than when charging. The linear relations between thermal energy conversion efficiencies, and the max and min temperature are discovered, proving that temperature distribution is determined by the thermal energy conversion efficiency. The increased max and min temperatures as function of a current rate and state of charge (SOC) or depth of discharge (DOD) are estimated and plotted as three-dimensional figures. Thus, the temperature range can be known according to the ranges of SOC/DOD and current rates. • Parameterized evaluation of thermal characteristics for a lithium ion battery is proposed. • The linear relations between thermal energy conversion efficiency, and the max and min temperature are found. • Quantitative relation of thermal behaviors to operating conditions is established. • Increased temperature as function of a current rate and SOC or DOD is estimated. [ABSTRACT FROM AUTHOR]

Ballast water is one of the main vectors for the spread of harmful organisms among geologically isolated waters. However, the successional processes of microbial functions and assembly processes in ballast water during the long-term shipping voyage remain unclear. In this study, the compositions, ecological functions, community assembly, and potential environmental drivers of bacteria and microeukaryotes were investigated in simulated ballast water microcosms for 120 days. The results showed that the diversity and compositions of the bacterial and microeukaryotic communities varied significantly in the initial 40 days (T0∼T40 samples) and then gradually converged. The relative abundance of Proteobacteria showed a distinct tendency to decrease (87.90%–41.44%), while that of Ascomycota exhibited an increasing trend (6.35%–62.12%). The functional groups also varied significantly over time and could be related to the variations of the microbial community. The chemoheterotrophy and aerobic chemoheterotrophy functional groups for bacteria decreased from 44.80% to 28.02% and from 43.77% to 25.39%, respectively. Additionally, co-occurrence network analysis showed that the structures of the bacterial community in T60∼T120 samples were more stable than those in T0∼T40 samples. Stochastic processes also significantly affected the community assembly of bacteria and microeukaryotes. pH played the most significant role in driving the structures and assembly processes of the bacterial and microeukaryotic communities. The results of this study could aid in the understanding of variations in the functions and ecological processes of bacterial and microeukaryotic communities in ballast water over time and provide a theoretical basis for its management. [Display omitted] • Obvious changes of bacterial and microeukaryotic communities occurred with time. • Microbial community became more similar with the increase of time. • Distinct variations of microbial functional groups occurred in simulated ballast water. • Stochasticity played a dominant role on bacterial and microeukaryotic communities assembly. • pH was the crucial factor driving the structures and assembly of microbial community. [ABSTRACT FROM AUTHOR]

Highlights: [•] We evaluate the effects of water depths on C, N and P stoichiometry of five submersed macrophytes. [•] Water depths affected growth of the plants significantly but weakly affected the plant C, N and P stoichiometry. [•] The plant species and their organs explained most of the variance in the C, N and P stoichiometry. [Copyright &y& Elsevier]

Abstract: The uptake kinetics of phosphate (Pi) by Myriophyllum spicatum was determined from adsorption and absorption under light and dark conditions. Pi uptake was light dependent and showed saturation following the Michaelis–Menten relation (in light: V =16.91×[Pi](1.335+[Pi]), R 2 =0.90, p <0.001; in the dark: V =5.13×[Pi](0.351+[Pi]), R 2 =0.77, p <0.001). Around 77% of the loss of Pi in the water column was absorbed into the tissue of M. spicatum, and only 23% was adsorbed on the surface of the plant shoots. Our study shows that M. spicatum shoots have a much higher affinity (in light: 3.9μmolg−1 dwh−1 μM−1; in the dark: 3.7μmolg−1 dwh−1 μM−1) and V max (maximum uptake rate, shoot light) for Pi uptake than many other aquatic macrophytes (in light: 0.002–0.23μmolg−1 dwh−1 μM−1; in the dark: 0.002–0.19μmolg−1 dwh−1 μM−1), which may provide a competitive advantage over other macrophytes across a wide range of Pi concentrations. [Copyright &y& Elsevier]

The superhydrophobic/superoleophilic copper hydroxide coated mesh was used for separating a series of water-in-oil emulsions. • The superhydrophobic copper hydroxide coated mesh was successfully fabricated by a simple spraying and surface modification process. • The as-prepared material was used for separating various water-in-oil emulsions effectively. • The as-prepared materials showed favorable recyclability. Recently, the super-wetting materials for separating oil/water emulsions have attracted great attention. Developing a low-cost and high-efficient filter material that is challenging to separate stable oil/water emulsions efficiently. In this work, the superhydrophobic copper hydroxide coated mesh was successfully fabricated through a facile spraying and surface modification approach. The excellent separation property of the as-prepared material with efficiency greater than 99.0% under the driving of gravity. Furthermore, the as-developed SCM retained the favorable recyclability and excellent stability even after 10 reuses. More importantly, the SCM exhibited excellent mechanical abrasion resistance after 50 abrasion cycles with sandpaper, which could still remove water from emulsions and possessed excellent separation efficiency. Therefore, the newly developed materials with special wettability have excellent potential in practical use and provide a novel perspective for preparation of stable emulsions separation materials. [ABSTRACT FROM AUTHOR]