The Sensitivity Analysis of a Lake Ecosystem with the Conditional Nonlinear Optimal Perturbation Method

The instability and sensitivity of a lake ecosystem to the finite-amplitude perturbations related to the initial condition and the parameter correspondingly are studied. The CNOP-I and CNOP-P methods are adopted to investigate this nonlinear system. The numerical results with CNOP-I method show that the lake ecosystem can be nonlinearly unstable with finite-amplitude initial perturbations when the nutrient loading rate is between the two bifurcation points. A large enough finite amplitude initial perturbation, that is, CNOP-I, can induce a transition from an oligotrophic (eutrophic) state to an eutrophic (oligotrophic) state. With CNOP-P method, it is shown that the lake ecosystem can be transformed from an oligotrophic (eutrophic) state to an eutrophic (oligotrophic) state with a large enough finite amplitude parameter perturbation, that is, CNOP-P, no matter how large the nutrient loading rate is

Formulations, Features of Solution Space, and Algorithms for Line-Pure Seru System Conversion

The line-seru conversion is usually used to improve productivity, especially in volatile business environment. Due to the simplicity, most researches focused on line-pure seru system conversion. We summarize the two existing models (i.e., a biobjective model and a single-objective model) of line-pure system conversion and formulate the three other usually used single-objective models in an integrated framework by combining evaluated performances and constraints. Subsequently, we analyze the solution space features of line-pure seru system conversion by dividing the whole solution space into several subspaces according to the number of serus. We focus on investigating the features between Cmax (and TLH) and subspaces. Thirdly, according to the distinct features between Cmax (and TLH) and subspaces, we propose four effective algorithms to solve the four single-objective models, respectively. Finally, we evaluate the computational performance of the developed algorithms by comparing with enumeration based on extensive experiments

Preparation and characterization of porous magnetic steel slag abrasives

To effectively solve the problems of environmental pollution and resource waste caused by steel slag and open up a new field of application of steel slag, the porous magnetic steel slag abrasive was prepared by combining the gas quenching process with steel slag as the main raw material. Besides, and the micro-morphology, the pore structure, the magnetic properties, the mechanical properties and the abrasive properties of steel slag abrasive were characterized by field emission scanning electron microscope, high-performance automatic mercury porosimeter, magnetometer, etc. The results show that the steel slag abrasive is monodisperse spherical, and there are disordered pores arranged in round or elliptical shape on its surface and cross section. The porosity of abrasive sample is 37% to 45%, and the pore volume is 0.18 to 0.23 mL/g. Under the action of external magnetic field, with the increase of the particle size of the abrasive sample, its hysteresis loop shifts clockwise and presents a narrow “S” type closed curve. The abrasive sample shows typical ferrous magnetism, which can effectively improve the surface quality of aluminum alloy workpiece, and the surface roughness Ra of the workpiece is reduced from 3.2 µm to 0.7 µm

<i>In Situ</i> Cavitation of Phenolic Supramolecules with PEO–PPO–PEO Block Copolymers by Friedel–Crafts Alkylation toward Ordered Nanoporous Polymers

The release of hydrogen halides in Friedel–Crafts alkylation has long been considered as troublesome and detrimental. Here we demonstrate that the released HCl in alkylation is beneficial and highly demanded to remove poly­(ethylene oxide)-<i>b</i>-poly­(propylene oxide)-<i>b</i>-poly­(ethylene oxide) templates from the phenolic supramolecules for the preparation of ordered nanoporous phenolic polymers as additional treatment for template removal is no longer necessary. Friedel–Crafts alkylation using bifunctional alkylation agent, 1,4-bis­(chloromethyl)­benzene, leads to the hyper-cross-linking of phenolic polymers, thus generating micropores in the skeleton of the polymers. HCl <i>in situ</i> generated as the byproduct during alkylation facilely extracts the copolymer because of its enhanced diffusion through the micropores. The prepared phenolic polymers exhibit high surface areas and well-ordered porosities in a hexagonal or gyriodal structure. The <i>in situ</i> cavitation by alkylation takes place at much milder conditions and has higher efficiency than other template-removing methods

Transcriptomic Analysis Reveals Transcription Factors Related to Leaf Anthocyanin Biosynthesis in Paeonia qiui

Paeonia qiui is a wild species of tree peony. P. qiui has good ornamental value owing to its leaf color change in spring. So far, the molecular mechanism of leaf color change in P. qiui is unclear. This study analyzes the anthocyanin level and transcriptome of two different color stages in P. qiui leaf. The purplish-red leaf stage is rich in anthocyanin, while the green leaf has very low levels of anthocyanin. Transcriptome analysis reveals that 6678 differentially-expressed genes (DEGs) are up-regulated, and 14,667 are down-regulated in the purplish-red leaf. Among these DEGs, 40 MYB (v-myb avian myeloblastosis viral oncogene homolog) genes, 40 bHLH (MYC-like basic helix–loop–helix) genes, and 15 WD40 (WD-repeat protein) genes were found. Based on phylogenetic and alignment analysis with the deduced amino acid sequences with known transcription factors, Unigene0024459 (MYB1) is likely the R2R3-MYB that promotes anthocyanin biosynthesis; Unigene0050761 (MYB2) is likely the R2R3-MYB that represses anthocyanin biosynthesis; Unigene0005081 (bHLH1) and Unigene0006146 (WD40-1) are likely the bHLH and WD40 that participate in regulating anthocyanin biosynthesis. Additionally, quantitative RT-PCR results confirmed the transcriptome analyses for key genes

A 22.3-Bit Third-Order Delta-Sigma Modulator for EEG Signal Acquisition Systems

This paper presents a high resolution delta-sigma modulator for continuous acquisition of electroencephalography (EEG) signals. The third-order single-loop architecture with a 1-bit quantizer is adopted to achieve 22.3-bit resolution. The effects of thermal noise on the performance of the delta-sigma modulator are analyzed to reasonably allocate the switched-capacitor sizes for optimal signal to noise ratio (SNR) and minimum chip area. The coefficients in feedback path and input path are optimized to avoid the signal distortion under the full-scale input voltage range with almost no increase in total capacitance sizes. Fabricated in 0.5 µm CMOS technology and powered by a 5 V voltage supply, the proposed delta-sigma modulator can achieve 136 dB peak SNR with 16 Hz input and 137 dB dynamic range in 100 Hz signal bandwidth with an oversampling ratio of 512. The modulator dissipates 700 µA. The core chip area is 1.96 mm2. The modulator occupies 1.41 mm2 and the decimator occupies 0.55 mm2

Effects of xylo-oligosaccharide and flavomycin on the immune function of broiler chickens

This study investigated the effects of xylo-oligosaccharide (XOS) and flavomycin (FLA) on the performance and immune function of broiler chickens. A total of 150 ArborAcres broilers were randomly divided into three groups and fed for six weeks from one day of age in cascade cages. The diets of each test group were (1) a basal diet, (2) the basal diet supplemented with 2 mg/kg FLA, and (3) the basal diet supplemented with 2 mg/kg XOS. At 21 and 42 days, the growth performance index values and short-chain fatty acid (SCFA) concentrations in the cecum were quantified. Furthermore, immunoglobulin G (IgG) and plasma interleukin 2 (IL-2) as well as mRNA expression of LPS-Induced TNF-alpha Factor (LITAF), Toll-like receptor-5 (TLR5) and interferon gamma (IFNγ) in the jejunum were quantified. The results showed that administration of XOS or FLA to chickens significantly improved the average daily gain. Supplementation with XOS increased acetate and butyrate in the cecum, while FLA supplementation increased propionate in the cecum. An increase in plasma IgG was observed in XOS-fed 21-day-old broilers, but FLA supplementation decreased IgG in the plasma of 42-day-old broilers and increased plasma IL-2. Furthermore, FLA or XOS supplementation downregulated mRNA expression of IFNγ, LITAF and TLR5. The above data suggest that addition of XOS and FLA to the diet could improve the growth performance of broilers and reduce the expression of cytokine genes by stimulating SCFA

Two kinds of ketoprofen enteric gel beads (CA and CS-SA) using biopolymer alginate

To obtain expected rapid-release and sustained-release of ketoprofen gel beads, this paper adopted biopolymer alginate to prepare alginate beads and chitosan-alginate gel beads. Formulation factors were investigated and optimized by the single factor test. The release of ketoprofen from calcium alginate gel beads in pH 1.0 hydrochloric acid solution was less than 10% during 2 h, then in pH6.8 was about 95% during 45 min, which met the requirements of rapid-release preparations. However, the drug release of chitosan-alginate gel beads in pH1.0 was less than 5% during 2 h, then in pH6.8 was about 50% during 6 h and reached more than 95% during 12 h, which had a good sustained-release behavior. In addition, the release kinetics of keteprofen from the calcium alginate gel beads fitted well with the Korsmeyer–Peppas model and followed a case-II transport mechanism. However, the release of keteprofen from the chitosan-alginate gel beads exhibited a non-Fickian mechanism and based on the mixed mechanisms of diffusion and polymer relaxation from chitosan-alginate beads. In a word, alginate gel beads of ketoprofen were instant analgesic, while chitosan-alginate gel beads could control the release of ketoprofen during gastro-intestinal tract and prolong the drug's action time. Keywords: Gel beads, Enteric rapid-release, Enteric sustained-release, Ketoprofe

Potential toxic components in size-resolved particles and gas from residential combustion: Emission factor and health risk

Particulate matter (PM) from residential combustion is an existential threat to human health. Emission factors (EFs) of multiple potential toxic components (PTCs) in size-resolved PM and gas from eight residential fuel combustion were measured, and size distribution, gas/particle partitioning and health risks of the PTCs were investigated. Average EFs from clean coal and anthracite coal were PTEs (sum of EFs of 11 Potential Toxic Elements, 6.62 mg/kg fuels) > PAHs (sum of 22 Polycyclic Aromatic Hydrocarbons, 1.12 mg/kg) > OPAHs (sum of 5 Oxygenated Polycyclic Aromatic Hydrocarbons, 0.45 mg/kg) > PAEs (sum of 6 Phthalate Esters, 0.11 mg/kg) > NPAHs (sum of 14 Nitropolycyclic Aromatic Hydrocarbons, 16.84 μg/kg) > OPEs (sum of 7 Organophosphate Esters, 7.57 μg/kg) > PCBs (sum of 6 Polychorinated Biphenyls, 0.07 μg/kg), which were 2–3 and 1–2 orders of magnitude lower than the EFs of PTCs (except PTEs) from bituminous coal and biomass. Most PAHs, OPAHs and NPAHs, which may mainly originate from chemical reactions, showed similar size distributions and averagely 85 % concentrated in PM1. PTEs, PAEs, OPEs and PCBs generated from the release from raw fuels may have a higher proportion, so their size distributions were more complex and varied with combustion temperature, volatility of compounds, binding mode of the raw fuels, and so on. In addition, clean coal and high-quality anthracite coal could reduce the health risks from the potential organic toxic components, but also reveal the stumbling block of PTEs in risk control

A liquid phosphorus-containing imidazole derivative as flame-retardant curing agent for epoxy resin with enhanced thermal latency, mechanical, and flame-retardant performances

The development of phosphorus-containing flame retardants combining good compatibility with matrix, low curing temperature, and mechanically reinforcing effect has remained a major challenge. Herein, we reported the synthesis of a liquid flame-retardant curing agent (DA) via the nucleophilic substitution between diphenylphosphinic chloride and 1-(3-aminopropyl)-imidazole (AI). DA exhibited good blending and latency towards epoxy resin (EP) at room temperature. According to DSC studies, DA could rapidly cure EP at moderate temperature. Compared with EP/AI sample, EP/DA samples displayed comparable or higher glass transition temperature (Tg) and enhanced mechanical properties due to the introduction of rigid diphenylphosphinyl group and improved cross-linking density. Moreover, DA improved the flame-retardant performances of EP thermoset. For instance, the LOI and UL94 rating of EP/DA-16 sample achieved 37.2 % and V-0, respectively. In addition, the peak of heat release rate (PHRR), average of heat release rate (AHRR), fire growth rate (FIGRA), and total heat release (THR) for EP/DA-16 sample reduced by 32 %, 42 %, 28 % and 27 % in comparison to EP/AI sample, respectively. DA was characterized by its good compatibility with EP, moderate curing temperature, fast curing rate, suitable thermal latency, mechanical reinforcing and flame-retardant effects, and thus it had a broad application prospect in various industrial fields