Chitosan/Ag-hydroxyapatite nanocomposite beads as a potential adsorbent for the efficient removal of toxic aquatic pollutants

© 2018 Elsevier B.V. In the present study, the potential of synthesized chitosan/Ag-substituted hydroxyapatite nanocomposite beads to remove basic dye, heavy metal and microbes from aqueous solutions was investigated. Beads were prepared in different ratios via embedding of Ag-hydroxyapatite (Ag-HA) into chitosan (CS) solution. The beads were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) in order to get an insight of the functional groups and morphology. Batch adsorption studies were conducted with copper ions (Cu (II)) and rhodamine B (RhB) dye by changing several parameters such as Ag-HA to Cs ratio, contact time, solution pH and initial concentration of pollutants. The antibacterial efficiency of beads was tested under dynamic contact conditions against commonly found bacteria in water, Escherichia coli. The adsorption isotherm data were best fitted with Langmuir model. The maximum Langmuir adsorption capabilities for Cu (II) ions and rhodamine B were found to be 40.11 mg/g and 127.61 mg/g, respectively. The adsorption process could be best described by pseudo-second-order kinetic model for both rhodamine B and Cu(II). The percentage removal efficiency of Cu (II) and rhodamine B from tap water and untreated river water ranged from 86.7 to 94.4% along with 99.99% of decontamination of microbial load

Chitosan/Al\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e-HA nanocomposite beads for efficient removal of estradiol and chrysoidin from aqueous solution

© 2019 Elsevier B.V. Alumina, as a support material, was loaded together with chitosan and hydroxyapatite to form chitosan/Al2O3-HA composite beads and was used for estradiol and chrysoidin removal from aqueous solution in the present work. The physicochemical properties of the beads were studied with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometry (FTIR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. FTIR spectra confirmed that the chitosan was loaded successfully on Al2O3-HA, and functional groups were immobilized onto the surface of the beads after the synthesis. The adsorption condition including pH, the amount of adsorbent, initial concentration and time were evaluated during the batch experiments. Isotherm data best matched the Langmuir model and the pseudo-second-order model best described the adsorption kinetics. The maximum adsorption capacity was found to be 39.78 mg/g and 23.26 mg/g for estradiol and chrysoidine, respectively. The adsorbed estradiol and chrysoidin were completely eluted from the composite beads with the eluent of 0.1 M H2SO4/MeOH and the regenerated material was used in several cycles without deterioration in its initial performances. This study suggests that the developed composite beads have high potential for the efficient removal estradiol and chrysoidin from aqueous solution

Lifelike Agility and Play on Quadrupedal Robots using Reinforcement Learning and Generative Pre-trained Models

Summarizing knowledge from animals and human beings inspires robotic innovations. In this work, we propose a framework for driving legged robots act like real animals with lifelike agility and strategy in complex environments. Inspired by large pre-trained models witnessed with impressive performance in language and image understanding, we introduce the power of advanced deep generative models to produce motor control signals stimulating legged robots to act like real animals. Unlike conventional controllers and end-to-end RL methods that are task-specific, we propose to pre-train generative models over animal motion datasets to preserve expressive knowledge of animal behavior. The pre-trained model holds sufficient primitive-level knowledge yet is environment-agnostic. It is then reused for a successive stage of learning to align with the environments by traversing a number of challenging obstacles that are rarely considered in previous approaches, including creeping through narrow spaces, jumping over hurdles, freerunning over scattered blocks, etc. Finally, a task-specific controller is trained to solve complex downstream tasks by reusing the knowledge from previous stages. Enriching the knowledge regarding each stage does not affect the usage of other levels of knowledge. This flexible framework offers the possibility of continual knowledge accumulation at different levels. We successfully apply the trained multi-level controllers to the MAX robot, a quadrupedal robot developed in-house, to mimic animals, traverse complex obstacles, and play in a designed challenging multi-agent Chase Tag Game, where lifelike agility and strategy emerge on the robots. The present research pushes the frontier of robot control with new insights on reusing multi-level pre-trained knowledge and solving highly complex downstream tasks in the real world

QTL mapping for plant height and ear height using bi-parental immortalized heterozygous populations in maize

IntroductionPlant height (PH) and ear height (EH) are key plant architectural traits in maize, which will affect the photosynthetic efficiency, high plant density tolerance, suitability for mechanical harvestingMethodsQTL mapping were conducted for PH and EH using a recombinant inbred line (RIL) population and two corresponding immortalized backcross (IB) populations obtained from crosses between the RIL population and the two parental lines.ResultsA total of 17 and 15 QTL were detected in the RIL and IB populations, respectively. Two QTL, qPH1-1 (qEH1-1) and qPH1-2 (qEH1-4) in the RIL, were simultaneously identified for PH and EH. Combing reported genome-wide association and cloned PH-related genes, co-expression network analyses were constructed, then five candidate genes with high confidence in major QTL were identified including Zm00001d011117 and Zm00001d011108, whose homologs have been confirmed to play a role in determining PH in maize and soybean.DiscussionQTL mapping used a immortalized backcross population is a new strategy. These identified genes in this study can provide new insights for improving the plant architecture in maize

Rapid determination of fumonisin (FB\u3csub\u3e1\u3c/sub\u3e) by syringe SPE coupled with solid-phase fluorescence spectrometry

© 2019 Fumonisin B1 is the most prevalent member of a family of toxins, known as fumonisins, which occurs mainly in maize, wheat and other cereals. Due to its hepatotoxic and nephrotoxic in all animal species, very strict regulations have been imposed on the levels of fumonisin B1 in cereal and cereal-based foods worldwide. In this work, a rapid determination method of fumonisin B1 by membrane solid phase extraction coupled with solid-phase fluorescence analysis is developed. A rhodamine based fluorescent probe was used for derivatization with fumonisin B1. After derivatization and extraction by nylon membrane, the enriched fumonisin B1 can be detected directly on the membrane without further elution process that is placed in a designed spectra collection device. The established method showed a linear relationship in concentration range of 0.5–5.0 μg/L, with the R2 = 0.991, and a limit of detection of 0.119 μg/L. Method accuracy was further confirmed using LC-MS method by comparing the detection results of 3 corn powder samples spiked with FB1, that demonstrated equivalent results. The results of this study indicated that the proposed method was simple, sensitive, reliable and suitable for trace fumonisins B1 quantitation in corn-based feeds

Evaluation of Geometrical Influence on the Hydrodynamic Characteristics and Power Absorption of Vertical Axisymmetric Wave Energy Converters in Irregular Waves

To obtain the mechanical energy of waves from arbitrary directions, the vibration absorbers of wave energy converters (WEC) are usually vertically axisymmetric. In such case, the wave-body interaction hydrodynamics is an essential research topic to obtain high-efficiency wave energy. In this paper, a semi-analytical method of decomposing the complex axisymmetric boundary into several ring-shaped stepped surfaces based upon the boundary approximation method (BAM) is introduced and examined. The hydrodynamic loads and parameters, such as the wave excitation forces, added mass and radiation damping of the vertical axisymmetric oscillating buoys, can then be achieved by using the new boundary discretisation method. The calculations of the wave forces and hydrodynamic coefficients show good convergence with the number of discretisation increases. Comparison between the constringent results and the results of the conventional method also verifies the feasibility of the method. Then, simulations and comparisons of the hydrodynamic forces, motions and wave power conversions of the buoys with series draught and displacement ratios in regular and irregular waves are conducted. The calculation results show that the geometrical shape has a great effect on the hydrodynamic and wave power conversion performance of the absorber. In regular waves, though the concave buoy has the lowest wave conversion efficiency, it has the largest frequency bandwidth for a given draught ratio, while in irregular waves, for a given draught ratio, the truncated cylindrical buoy has the best wave power conversion, and for a given displacement of the buoy, the concave buoy shows the best wave power conversion ability

On-chip solid phase extraction and in situ optical detection

© 2019 Elsevier B.V. A device was designed integrating solid phase extraction (SPE) and in situ optical detection techniques. A chip assembled in the device to carry out SPE was enclosed in a fully reflective aluminum box to avoid loss of radiation flux in the optical measurement. The spectrum was measured on the SPE material directly after SPE. The device offers simple analytical operation without any elution step comparing with the traditional analytical methods with complicated procedures. The device and the developed analytical technique was used for the determination of rhodamine B and benzo[a]pyrene with UV–visible diffuse reflectance and solid phase fluorescence spectroscopies, respectively. Under optimal conditions, standard curves of rhodamine B and benzo[a]pyrene showed a linear relationship in concentration ranges of 10–800 μg L-1 (R2 = 0.99) and 0.07–3.33 μg L-1 (R2 = 0.99), respectively. The limit of detections (LOD) were 7 μg L-1 and 0.02 μg L-1. The proposed device was successfully employed to quantify rhodamine B and benzo[a]pyrene in tap water samples. The results showed that the recoveries were 90–105% and the relative standard deviations (RSDs) were 2.53–5.55%, indicating that the device and analytical method is capable of trace analytes for rapid quantitative analysis in various samples

A translatome-transcriptome multi-omics gene regulatory network reveals the complicated functional landscape of maize

Abstract Background Maize (Zea mays L.) is one of the most important crops worldwide. Although sophisticated maize gene regulatory networks (GRNs) have been constructed for functional genomics and phenotypic dissection, a multi-omics GRN connecting the translatome and transcriptome is lacking, hampering our understanding and exploration of the maize regulatome. Results We collect spatio-temporal translatome and transcriptome data and systematically explore the landscape of gene transcription and translation across 33 tissues or developmental stages of maize. Using this comprehensive transcriptome and translatome atlas, we construct a multi-omics GRN integrating mRNAs and translated mRNAs, demonstrating that translatome-related GRNs outperform GRNs solely using transcriptomic data and inter-omics GRNs outperform intra-omics GRNs in most cases. With the aid of the multi-omics GRN, we reconcile some known regulatory networks. We identify a novel transcription factor, ZmGRF6, which is associated with growth. Furthermore, we characterize a function related to drought response for the classic transcription factor ZmMYB31. Conclusions Our findings provide insights into spatio-temporal changes across maize development at both the transcriptome and translatome levels. Multi-omics GRNs represent a useful resource for dissection of the regulatory mechanisms underlying phenotypic variation