Time-delayed chameleon: Analysis,synchronization and FPGA implementation

In this paper we report a time-delayed chameleon-like chaotic system which can belong to different families of chaotic attractors depending on the choices of parameters. Such a characteristic of self-excited and hidden chaotic flows in a simple 3D system with time delay has not been reported earlier. Dynamic analysis of the proposed time-delayed systems are analysed in time-delay space and parameter space. A novel adaptive modified functional projective lag synchronization algorithm is derived for synchronizing identical time-delayed chameleon systems with uncertain parameters. The proposed time-delayed systems and the synchronization algorithm with controllers and parameter estimates are then implemented in FPGA using hardware–software co-simulation and the results are presented.     

Extended Holomorphic Anomaly in Gauge Theory

The partition function of an N=2{\mathcal {N}=2} gauge theory in the Ω-background satisfies, for generic value of the parameter b = -e₁/e₂{\beta=-{\epsilon_1}/{\epsilon_2}} , the, in general extended, but otherwise β-independent, holomorphic anomaly equation of special geometry. Modularity together with the (β-dependent) gap structure at the various singular loci in the moduli space completely fixes the holomorphic ambiguity, also when the extension is non-trivial. In some cases, the theory at the orbifold radius, corresponding to β = 2, can be identified with an “orientifold” of the theory at β = 1. The various connections give hints for embedding the structure into the topological string.     

Detection of nanoparticles in edible plant tissues exposed to nano-copper using single-particle ICP-MS

The increasing use of nanopesticides has raised concerns about their effects on crop plants and the impact of human health as well as ecological effects. While increased uptake of metal ions has been observed before, to date, very few studies have demonstrated the presence of nanoparticles in edible tissues. Single-particle inductively coupled plasma–mass spectrometry (sp-ICP-MS) has been suggested as a powerful tool to detect inorganic nanoparticles (NPs) in environmental samples. Here, we exposed edible plant tissues from lettuce, kale, and collard green to nano-CuO, simulating its use as a nanopesticide. We applied sp-ICP-MS to demonstrate the presence of nanoparticles, both in the water used to rinse crop leaf surfaces exposed to nano-CuO and within the leaf tissues. Lettuces retained the highest amounts of nCuO NPs on the leaf surface, followed by collard green and then kale. Surface hydrophilicity and roughness of the leaf surfaces played an important role in retaining nano-CuO. The results indicate that most of the nanoparticles are removed via washing, but that a certain fraction is taken up by the leaves and can result in human exposure, albeit at low levels.

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Graphical abstract ?

     

One-step hydrothermal synthesis of feather duster-like NiS@MoS<Subscript>2</Subscript> with hierarchical array structure for the Pt-free dye-sensitized solar cell

Novel feather duster-like nickel sulfide (NiS) @ molybdenum sulfide (MoS₂) with hierarchical array structure is synthesized via a simple one-step hydrothermal method, in which a major structure of rod-like NiS in the center and a secondary structure of MoS₂ nanosheets with a thickness of about 15–55 nm on the surface. The feather duster-like NiS@MoS₂ is employed as the counter electrode (CE) material for the dye-sensitized solar cell (DSSC), which exhibits superior electrocatalytic activity due to its feather duster-like hierarchical array structure can not only support the fast electron transfer and electrolyte diffusion channels, but also can provide high specific surface area (238.19 m² g^?1) with abundant active catalytic sites and large electron injection efficiency from CE to electrolyte. The DSSC based on the NiS@MoS₂ CE achieves a competitive photoelectric conversion efficiency of 8.58%, which is higher than that of the NiS (7.13%), MoS₂ (7.33%), and Pt (8.16%) CEs under the same conditions.

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Graphical abstract Novel feather duster-like NiS@MoS₂ hierarchical structure array with superior electrocatalytic activity was fabricated by a simple one-step hydrothermal method.

     

Effect of alkyl chain lengths on the assemblies of magnetic nanoparticles coated with multi-functional thiolactone-containing copolymer

This work presents the synthesis of magnetite nanoparticle (MNP) coated with poly(N,N-diethylaminoethyl methacrylate)-b-poly(N-isopropyl acrylamide-st-thiolactone acrylamide) (PDEAEMA-b-P(NIPAAm-st-TlaAm) copolymer and its use in controlled drug release and bio-conjugation. TlaAm units in the copolymer were ring-opened with various alkyl amines to form thiol groups (-SH), followed by thiol-ene coupling reactions with acrylamide-coated MNP and then quaternized to obtain cationic copolymer-MNP assemblies (the size <?200 nm/cluster). The use of alkyl amines having various chain lengths (e.g., 1-propylamine, 1-octylamine, or 1-dodecylamine) in the nucleophilic ring-opening reactions of the thiolactone rings affected their magnetic separation ability, water dispersibility, and release rate of doxorubicin model drug. In all cases, when increasing the temperature, they showed a thermo-responsive behavior as indicated by the decrease in hydrodynamic size and the accelerated drug release rate. These copolymer-MNP assemblies could be used as a novel platform with thermal-triggering controlled drug release and capability for adsorption with any negatively charged biomolecules.

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Graphical abstract MNP coated with multi-functional PDEAEMA-b-P(NIPAAm-st-TlaAm) copolymer and its proposed drug release

     

Nondestructive interface construction for CdS-buffered ZnO nanorod/Cu<Subscript>2</Subscript>O composite structure solar cells

In this work, ZnO nanorod/Cu₂O composite nanostructure solar cells were prepared using hydrothermal growth and electrodeposition. The CdS layer was added between ZnO and Cu₂O to suppress carrier reverse recombination. Nondestructive interface deposition methods were employed to prepare CdS and Cu₂O functional layers. The CdS layers were unconventionally deposited in non-alkaline solution, which can inhibit etching on the ZnO surface, and Cu₂O layers were electrodeposited in ZnO-buffered alkaline solution which can also inhibit etching on the ZnO surface. Finally, the performance of solar cells was improved by adding a highly resistive CdS intermediate layer between ZnO and Cu₂O layers. This work demonstrated the nondestructive interface approach of chemical solution deposition of functional layers on ZnO and possibilities for further improvements to the performance of Cu₂O-based nanostructure solar cells with the addition of an intermediated layer.     

Characterization of Zn<Subscript>2</Subscript>SnO<Subscript>4</Subscript> Thin Films Prepared by RF Magnetron Sputtering

Zn₂SnO₄ (ZTO) is a stable semiconductor in ZnO–SnO₂ system and important transparent conducting oxide (TCO) predominantly used in optoelectronic devices. ZTO thin films were prepared by RF magnetron sputtering using Zn₂SnO₄ ceramic target in this paper. The effects of annealing temperatures and oxygen contents on characterization of ZTO thin films were studied. The results show that ZTO thin films prepared by RF magnetron sputtering are amorphous with an optical band gap of 3.22 eV. After annealing at 650°C in Ar atmosphere for 40 min, ZTO films possess a spinel structure with an optical band gap of 3.62 eV. The atomic force microscope (AFM) data of morphology reveals that the surface roughness of films is about 2 nm. The results of energy dispersive spectrometer (EDS) show that the concentration ratio of Zn to Sn is in the range from 1.44 to 1.57. The results of Hall-effect-measurement system reveal that the resistivity of films varies from 102 to 10–1 Ωcm, carrier concentration is about 10¹⁷ cm^–3, and mobility ranges from 10⁰ to 10¹ cm² v^–1 s^–1.     

Influence of non-Gaussian noise on a tumor growth system under immune surveillance

In this paper, the stationary probability distribution (SPD) function and the mean first passage time (MFPT) are investigated in a tumor growth model driven by non-Gaussian noise which is introduced to mimic random fluctuations in the levels of the immune system. Results demonstrate the different transitions induced by the strength of non-Gaussian noise under different immune coefficients and the dual roles of non-Gaussian noise in promoting host protection against cancer and in facilitating tumor escape from immune destruction. Additionally, it can be discovered that increases in noise strength, the degree of departure from Gaussian noise, and the immune coefficient can accelerate the extinction of tumor cells. Numerical simulations are performed, and their results present good agreement with the theoretical results.     

Carpet oscillator: A new megastable nonlinear oscillator with infinite islands of self-excited and hidden attractors

Polarisation of the particle spin can be an important problem for different plasmas. In this article, the contribution of the electron spin on the growth rate of the temperature anisotropy of electromagnetic instabilities has been investigated. Results show that polarisation of the electron spin will restrict the instability growth rate while instability can survive due to the spin-depolarised electrons even when the requested temperature anisotropy is vanished. Instability can reach the damping state exponentially due to the spin-polarised electrons while it can grow linearly due to the spin-depolarised (the semi-classical) electrons.     

Envisaging quantum transport phenomenon in a muddled base pair of DNA

The effect of muddled base pair on electron transfer through a deoxyribonucleic acid (DNA) molecule connected to the gold electrodes has been elucidated using tight binding model. The effect of hydrogen and nitrogen bonds on the resistance of the base pair has been minutely observed. Using the semiempirical extended Huckel approach within NEGF regime, we have determined the current and conductance vs. bias voltage for disordered base pairs of DNA made of thymine (T) and adenine (A). The asymmetrical behaviour amid five times depreciation in the current characteristics has been observed for deviated Au–AT base pair–Au devices. An interesting revelation is that the conductance of the intrinsic AT base pair configuration attains dramatically high values with the symmetrical zig-zag pattern of current, which clearly indicates the transformation of the bond length within the strands of base pair when compared with other samples. A thorough investigation of the transmission coefficients T(E) and HOMO–LUMO gap reveals the misalignment of the strands in base pairs of DNA. The observed results present an insight to extend this work to build biosensing devices to predict the abnormality with the DNA.