Seasonal, 2-D sedimentary extracellular enzyme activities and controlling processes in Great Peconic Bay, Long Island

Extracellular enzymes (EE) initiate heterotrophic remineralization by hydrolyzing high-molecularweight organic matter to substrates that are sufficiently small (approximately 600 Da) to be transported across cell membranes. An accurate understanding of EE associated remineralization processes in sedimentary deposits requires measuring patterns of extracellular enzyme activity (EEA) with minimal disturbance of natural sediment structure. In this study, two-dimensional patterns of extracellular enzyme (leucine aminopeptidase) activity in shallow-water, marine sediments from Great Peconic Bay, Long Island, New York were examined seasonally at sub-millimeter resolution by using a newly developed EE planar fluorosensor. Comparisons of spatially averaged, vertical enzyme activity profiles measured using this imaging sensor system and traditional sediment homogenization techniques verified the overall consistency of the methodology. The depth-averaged EEA (approximately 10 cm) varied seasonally with highest levels in the late spring through summer (0.2 μmol substrate g-wet-wt–1 hr–1) and lowest in the late fall and early winter (0.1 μmol substrate g-wet-wt–1 hr–1). EEA distributions, however, showed extensive small-scale horizontal heterogeneity as well as vertical variations. Both the input of reactive substrates (planktonic organic matter) and temperature differences accounted for major changes in EEA seasonally. In general, horizontal heterogeneity in EEA was greatest during warm seasons (summer, fall) as a result of increased macrofaunal activity. On the other hand, vertical variations are less significant during warm periods compared with cold periods as the sediment is more intensely reworked. Hot spots of elevated microbial activity from sub-millimeter to millimeter scales are observed in some seasons and are specifically associated with substrate inputs from phytoplankton blooms and particle reworking by infauna. The deposition of phytodetritus from an early spring bloom greatly enhanced surface sediment EEA, and at this time high EEA closely coincided with regions of elevated metabolite production as measured by NH+4 and ΣCO2 concentrations. Direct correlations between averaged EEA distributions and nutrient production rates were observed throughout the year but no correlations between EEA and pore water nutrient concentrations were present. Spatially resolved EEA directly tracks reactive particle distributions and is generally independent of solute transport mechanisms, such as bioirrigation, and redox conditions

MetaBox: A Benchmark Platform for Meta-Black-Box Optimization with Reinforcement Learning

Recently, Meta-Black-Box Optimization with Reinforcement Learning (MetaBBO-RL) has showcased the power of leveraging RL at the meta-level to mitigate manual fine-tuning of low-level black-box optimizers. However, this field is hindered by the lack of a unified benchmark. To fill this gap, we introduce MetaBox, the first benchmark platform expressly tailored for developing and evaluating MetaBBO-RL methods. MetaBox offers a flexible algorithmic template that allows users to effortlessly implement their unique designs within the platform. Moreover, it provides a broad spectrum of over 300 problem instances, collected from synthetic to realistic scenarios, and an extensive library of 19 baseline methods, including both traditional black-box optimizers and recent MetaBBO-RL methods. Besides, MetaBox introduces three standardized performance metrics, enabling a more thorough assessment of the methods. In a bid to illustrate the utility of MetaBox for facilitating rigorous evaluation and in-depth analysis, we carry out a wide-ranging benchmarking study on existing MetaBBO-RL methods. Our MetaBox is open-source and accessible at: https://github.com/GMC-DRL/MetaBox.Comment: Accepted at NuerIPS 202

The collecting performance and interaction mechanism of sodium diisobutyl dithiophosphinate in sulfide minerals flotation

The interaction mechanism of sodium diisobutyl dithiophosphinate (DTPINa) with chalcopyrite, pyrite, galena and sphalerite was investigated by single mineral flotation experiment, adsorption measurement and FTIR spectrum analysis. Single mineral flotation experiments showed that sodium diisobutyl dithiophosphinate exhibited a strong ability to collect chalcopyrite and galena. For chalcopyrite and pyrite, the recovery of chalcopyrite can reach 96.2% when the dosage is 12 mg/L and pH value is 8. In the same situation, the recovery of pyrite is as low as 13.5%. For galena and sphalerite, the recovery of galena reached 91.7% when the dosage was 50 mg/L at pH 11, and the recovery of sphalerite was only 16.9%. DTPINa adsorbed on chalcopyrite and galena surfaces are more than that on pyrite and sphalerite surfaces. The adsorption capacity of DTPINa on the minerals surface is proportional to its dosage. The FTIR spectrum analysis results showed that the adsorption of DTPINa on sulfide minerals surface is chemical and S atoms in PS and PS may have taken part in the reaction. The natural ores experiments also confirmed the excellent performance of sodium diisobutyl dithiophosphinate

Biomass Straw-Derived Porous Carbon Synthesized for Supercapacitor by Ball Milling

A large amount of biomass straw waste is generated every year in the world, which can cause serious environmental pollution and resource waste if disposed of improperly. At present, biomass-derived porous carbon materials prepared from biomass waste as a carbon source have garnered attention due to their renewability, huge reserves, low cost, and environmental benevolence. In this work, high-performance carbon materials were prepared via a one-step carbonization-activation method and ball milling, with waste tobacco straw as precursor and nano-ZnO as template and activator. The specific surface area and porous structure of biomass-derived carbon could be controlled by carbonization temperature, which is closely related to the electrochemical performances of the carbon material. It was found that, when the carbonization temperature was 800 °C, the biochar possesses maximum specific surface area (1293.2 m2·g−1) and exhibits high capacitance of 220.7 F·g−1, at 1 A·g−1 current density in a three-electrode configuration with 6 M KOH aqueous solution. The capacitance retention maintained about 94.83% at 5 A·g−1 after 3000 cycles. This work proves the porous biochar derived from tobacco straws has a great potential prospect in the field of supercapacitors

Research on High-Value Utilization of Carbon Derived from Tobacco Waste in Supercapacitors

Large quantities of tobacco stalks residues are generated and discarded as crop waste or combusted directly every year. Thus, we need to find an appropriate way to dispose of this type of waste and recycle it. The conversion of biomass waste into electrode materials for supercapacitors is entirely in line with the concept of sustainability and green. In this paper, tobacco-stalk-based, porous activated carbon (TC) was successfully synthesized by high-temperature and high-pressure hydrothermal pre-carbonization and KOH activation. The synthesized TC had a high pore volume and a large surface area of 1875.5 m2 g−1, in which there were many mesopores and interconnected micro-/macropores. The electrochemical test demonstrated that TC-1 could reach a high specific capacitance of up to 356.4 F g−1 at a current density of 0.5 A g−1, which was carried in 6M KOH. Additionally, a symmetrical supercapacitor device was fabricated by using TC-1 as the electrode, which delivered a high energy density up to 10.4 Wh kg−1 at a power density of 300 W kg−1, and excellent long-term cycling stability (92.8% of the initial capacitance retention rate after 5000 cycles). Therefore, TC-1 is considered to be a promising candidate for high-performance supercapacitor electrode materials and is a good choice for converting tobacco biomass waste into a resource

Grazing impact of microzooplankton on phytoplankton in the Xiamen Bay using pigment-specific dilution technique

Phytoplankton group-specific growth and microzooplankton grazing were determined seasonally using the dilution technique with high-performance liquid chromatography (HPLC) in the Xiamen Bay, a subtropical bay in southeast China, between May 2003 and February 2004. The results showed that growth rates of phytoplankton ranged from 0.71 to 2.2 d(-1) with the highest value occurred in the inner bay in May. Microzooplankton grazing rates ranged from 0.5 to 3.1 d(-1) with the highest value occurred in the inner bay in August. Microzooplankton grazing impact ranged from 39\% to 95\% on total phytoplankton Chl a biomass, and 65\% to 181\% on primary production. The growth and grazing rates of each phytoplankton group varied, the highest growth rate (up to 3.3 d(-1)) was recorded for diatoms in August, while the maximum grazing rate (up to 2.1 d(-1)) was recorded for chlorophytes in February in the inner bay. Among main phytoplankton groups, grazing pressure of microzooplankton ranged from 10\% to 83\% on Chl a biomass, and from 14\% to 151\% on primary production. The highest grazing pressure on biomass was observed for cryptophytes (83\%) in August, while the maximum grazing pressure on primary production was observed for cyanobacteria (up to 151\%) in December in the inner bay. Net growth rates of larger phytoplanktons (diatoms and dinoflagellates) were higher than those of smaller groups (prasinophytes, chlorophytes and cyanobacteria). Relative preference index showed that microzooplankton grazed preferentially on prasinophytes and avoided to harvest diatoms in cold seasons (December and February)

Spatial and temporal distribution of nanoflagellates in the northern South China Sea

Seasonal variation, horizontal and vertical distribution, and cell size of nanoflagellates, together with physico-chemical and biological factors, were studied in the northern South China Sea (SCS). It was found that nanoflagellate abundance ranged from 0.157 x 10(3) to 9.193 x 10(3) cells/ml (with a mean of 0.891 x 10(3)) in winter (February, 2004), while it ranged from 0.107 x 10(3) to 5.417 x 10(3) cells/ml (with a mean of 0.599 x 10(3)) in summer (July, 2004). Nanoflagellates were more abundant in winter than summer in offshore regions, showing an unique seasonal pattern in this subtropical marginal sea. The abundance of nanoflagellates decreased from the estuary to the offshore region. Vertical distribution of nanoflagellates coupled well with that of bacteria and Chl a. The small size fraction of less than 5 mu m dominated the nanoflagellate populations. Wind-driven mixing, eddies, availability of nutrients as well as Chl a and abundance of picoplankton seemed to be the major controlling factors for the spatial distribution and seasonal variation of nanoflagellates in the study area

Grazing impact of microzooplankton on phytoplankton in the Xiamen Bay using pigment-specific dilution technique

Phytoplankton group-specific growth and microzooplankton grazing were determined seasonally using the dilution technique with high-performance liquid chromatography (HPLC) in the Xiamen Bay, a subtropical bay in southeast China, between May 2003 and February 2004. The results showed that growth rates of phytoplankton ranged from 0.71 to 2.2 d(-1) with the highest value occurred in the inner bay in May. Microzooplankton grazing rates ranged from 0.5 to 3.1 d(-1) with the highest value occurred in the inner bay in August. Microzooplankton grazing impact ranged from 39% to 95% on total phytoplankton Chl a biomass, and 65% to 181% on primary production. The growth and grazing rates of each phytoplankton group varied, the highest growth rate (up to 3.3 d(-1)) was recorded for diatoms in August, while the maximum grazing rate (up to 2.1 d(-1)) was recorded for chlorophytes in February in the inner bay. Among main phytoplankton groups, grazing pressure of microzooplankton ranged from 10% to 83% on Chl a biomass, and from 14% to 151% on primary production. The highest grazing pressure on biomass was observed for cryptophytes (83%) in August, while the maximum grazing pressure on primary production was observed for cyanobacteria (up to 151%) in December in the inner bay. Net growth rates of larger phytoplanktons (diatoms and dinoflagellates) were higher than those of smaller groups (prasinophytes, chlorophytes and cyanobacteria). Relative preference index showed that microzooplankton grazed preferentially on prasinophytes and avoided to harvest diatoms in cold seasons (December and February).The National Natural Science Foundation of China [40730846, 40521003]; Ministry of Science and Technology of China [2006CB400604

Deep learning models incorporating endogenous factors beyond DNA sequences improve the prediction accuracy of base editing outcomes

Abstract Adenine base editors (ABEs) and cytosine base editors (CBEs) enable the single nucleotide editing of targeted DNA sites avoiding generation of double strand breaks, however, the genomic features that influence the outcomes of base editing in vivo still remain to be characterized. High-throughput datasets from lentiviral integrated libraries were used to investigate the sequence features affecting base editing outcomes, but the effects of endogenous factors beyond the DNA sequences are still largely unknown. Here the base editing outcomes of ABE and CBE were evaluated in mammalian cells for 5012 endogenous genomic sites and 11,868 genome-integrated target sequences, with 4654 genomic sites sharing the same target sequences. The comparative analyses revealed that the editing outcomes of ABE and CBE at endogenous sites were substantially different from those obtained using genome-integrated sequences. We found that the base editing efficiency at endogenous target sites of both ABE and CBE was influenced by endogenous factors, including epigenetic modifications and transcriptional activity. A deep-learning algorithm referred as BE_Endo, was developed based on the endogenous factors and sequence information from our genomic datasets, and it yielded unprecedented accuracy in predicting the base editing outcomes. These findings along with the developed computational algorithms may facilitate future application of BEs for scientific research and clinical gene therapy