Search

Sugarcane bagasse is a rich source of bioactive compounds (e.g., phenolics) known to have antimicrobial, antioxidant, anticancer, and anti-inflammatory properties. These bioactive molecules can be used in the green synthesis of metal nanoparticles. Metal nanoparticles have gathered attention because of their novel physico-chemical properties and potential biological applications (e.g., biocides, pesticides, plant biostimulants). Silver nanoparticles are of particular interest as they can be easy to operate and are cost effective, biocompatible, and their biological activities can be enhanced by surface modifications. In this study, the reducing potential of the phenolic compounds extracted from sugarcane bagasse was investigated for the synthesis of silver nanoparticles without the external addition of reducing agents. The reddish color formation and peak appearance at 420 nm were indications of the successful synthesis of the silver nanoparticles. The synthesized nanoparticles were further characterized by microscopy techniques indicating nanoparticles of spherical shape and with particle sizes averaging -15 nm. The antimicrobial activity of the synthesized nanoparticles was evaluated against several microbial species, some of which had been isolated from cane juice. The synthesized nanoparticles showed a biocidal effect against bacteria which was further confirmed by microscopy techniques. It appears that the nanoparticles are interacting with the cell surface of microorganisms, penetrating the cell and also causing the disruption of intracellular organelles. These nanoparticles can also reduce the growth of microbial biofilms. A biofilm is a complex and functional community of microbes encased in a primarily polysaccharide matrix, which act as a barrier to protect microbes against most biocides. [ABSTRACT FROM AUTHOR]

Graphene reinforced metal matrix composites represent a promising class of materials for high-strength surface coatings because of their high strength and ductility. This study reports the application of different interatomic potentials to correctly describe the interaction between graphene and metals (Al, Cu, Ni, and Ti) by molecular dynamics. Both simple pair potentials, such as Lennard-Jones and Morse, and many-body potentials, such as bond order potential are applied for the simulation of a graphene/metal system at room temperature. Three different structures are considered: (i) graphene interacting with one metal atom; (ii) graphene interacting with a metal nanoparticle, and (iii) three-dimensional graphene network filled with metal nanoparticles. We first determine the potential energy that any graphene/metal system can reach during exposure at 300 K; then, we analyze the interaction dynamics for all considered systems and all potentials. A considerable difference in the interaction between metal nanoparticles with planar and folded graphene was found. For graphene/Ni, graphene/Cu, and graphene/Ti, the Lennard-Jones and Morse potentials provide accurate energetic and structural properties of the studied structures; they also describe interaction in the graphene/metal system in a similar way, at variance with bond-order potential. For graphene/Al, the Tersoff and Morse potentials describe the interaction better than Lennard-Jones. For the simulation of graphene/Me system, the optimal choice of the potential for different structures is of crucial importance. The presented analysis of the interatomic potentials appears to be promising for realistic and accurate simulations of graphene reinforced metal composites. • The applicability of interatomic potentials to describe the interaction of graphene with Al, Cu, Ni and Ti was analyzed. • Crumpled graphene filled with metal nanoparticles at various conditions was studied by molecular dynamics. • For each case, the interatomic potential that better reproduces the behavior of the metal/graphene system was defined. [ABSTRACT FROM AUTHOR]

The article presents the discussion on disposal leading to the leaching of toxic metals. Topics include recycling requires immense amounts of energy and producing polluting chemicals; banning the sale of petrol, diesel, and hybrid cars for the demand of lithium ion batteries; and concerning about the environmental and ethical effect of metal mining.

Purpose A porous medium saturated with a nanofluid based on pure water and copper nanoparticles is used for cooling a hemispherical electronic device contained in an annulus space. The disc of the cavity could be inclined at an angle ranging from 0 ° (horizontal disc with dome facing upwards) to 180° (horizontal disc with dome facing downwards). The important surface heat flux generated by the dome leads to high Rayleigh number values reaching 7.29 × 10^10. The purpose of this work is to examine the influence of the nanofluid saturated porous medium on the free convective heat transfer.Design/methodology/approach Heat transfer occurring between this active component and the isothermal passive cupola is quantified by means of a three-dimensional numerical study using the control volume method associated to the SIMPLE algorithm.Findings The work shows that heat transfer in the annulus space is improved by interposing a porous medium saturated with the water-copper nanofluid.Originality/value New correlation is proposed to calculate the Nusselt number for any combination of the inclination angle, the fraction volume, the Rayleigh number and the ratio between the thermal conductivities of the porous medium and the fluid. The wide ranges corresponding to these parameters allow the thermal design of this electronic equipment for various configurations. [ABSTRACT FROM AUTHOR]

Abstract In this letter, we have explored the effects of nanoparticles on unsteady pulsatile blood flow through a curved overlapping stenosed channel. The governing differential equations are derived for the given physical problem and this contains momentum and energy equations along with suitable boundary conditions. An explicit finite difference technique has been used to calculate the numerical results of the given differential equations. The numerical results for different values of curved parameter (R c) , nanoparticles (Cu, TiO 2 , Al 2 O 3) and Grashof numbers (Gr) are calculated in order to analyze the effects of these parameters on blood flow pattern. A notable deviation in the results of blood flow pattern has been observed with the comparison of pure blood with nano-fluids. It is further noted that the curved parameter (R c) of a channel has a great influence on velocity profile, flow rate and impedance/resistance to flow. It is also extracted from the velocity profiles that the shape of the velocity curves reduces to symmetric pattern for the higher values of the curved parameters (R c). Similarly, the magnitude of temperature profiles is constricted due to the insertion of nanoparticles within blood. Moreover, streamlines are also calculated in order to analyze the effects of nanoparticles inside the circulating regions of the flow field. [ABSTRACT FROM AUTHOR]

Purpose The paper aims to examine the boundary layers of a three-dimensional stagnation point flow of Al-Cu nanoparticle-suspended water-based nanofluid in an electrically conducting medium. The effect of magnetic field on second-order slip effect and convective heating is also taken into account.Design/methodology/approach The thermophysical properties of alloy nanoparticles such as density, specific heat capacity and thermal conductivity are computed using appropriate formula. The non-linear parabolic partial differential equations are transformed to ordinary differential equations and solved by shooting technique.Findings The influence of compositional variation of alloy nanoparticle, nanoparticle concentration, magnetic effect, slip parameters and Biot number are presented for various flow characteristics. Interesting results on skin friction and Nusselt number are obtained for different composition of aluminium and copper.Originality/value A novel result of the analysis reveals that impact of magnetic field near the boundary is suppressed by the slip effect. [ABSTRACT FROM AUTHOR]

Ichthyophthirius multifiliis is a widespread, ciliated protozoan ectoparasite of fish. In the present study, we investigated the effects of metal nanoparticles on the reproduction and infectivity of free-living stages of I. multifiliis. We determined that ~50% of theronts could be killed within 30 min of exposure to either 20 ng mL−1 gold, 10 ng mL−1 silver or 5 ng mL−1 zinc oxide nanoparticles. Silver and zinc oxide nanoparticles at concentration of 10 and 5 ng mL−1 killed 100 and 97% of theronts, respectively and inhibited reproduction of tomonts after 2 h exposure. Gold nanoparticles at 20 ng mL killed 80 and 78% of tomonts and theronts 2 h post exposure, respectively. In vivo exposure studies using rainbow trout (Oncoryhnchus mykiss) demonstrated that theronts, which survived zinc oxide nanoparticles exposure, showed reduced infectivity compared with control theronts. No mortalities were recorded in the fish groups cohabited with theronts exposed to either nanoparticles compared with 100% mortality in the control group. On the basis of the results obtained from this study, metal nanoparticles particularly silver nanoparticles hold the best promise for the development of effective antiprotozoal agents useful in the management of ichthyophthiriosis in aquaculture. [ABSTRACT FROM AUTHOR]

The article discusses the use of single-cell inductively coupled plasma mass spectroscopy (ICP-MS) to determine the relationship between metal levels in cells and diseases. Particular focus is given to the benefits of using single-cell ICP-MS and highlights on topics including determination of the inefficiency of the drug Cisplatin, measuring metal content to attogram size, and determining the size of nanoparticles. INSETS: The single-cell ICP-MS instrument;Follow that cell: an NIH challenge.

Interaction of metal or oxide nanoparticles (NPs) with biological soft matter is one of the central phenomena in basic and applied biology-oriented nanoscience. Often, this interaction includes adsorption of suspended proteins on the NP surface, resulting in the formation of the protein corona around NPs. Structurally, the corona contains a “hard” monolayer shell directly contacting a NP and a more distant weakly associated “soft” shell. Chemically, the corona is typically composed of a mixture of distinct proteins. The corresponding experimental and theoretical studies have already clarified many aspects of the corona formation. The process is, however, complex, and its understanding is still incomplete. Herein, we present a kinetic mean-field model of the formation of the “hard” corona with emphasis on the role of (i) protein-diffusion limitations and (ii) interplay between competitive adsorption of distinct proteins and irreversible reconfiguration of their native structure. The former factor is demonstrated to be significant only in the very beginning of the corona formation. The latter factor is predicted to be more important. It may determine the composition of the corona on the time scales comparable or longer than a few hours. [ABSTRACT FROM AUTHOR]

Theoretically, the determination of the structure of a cluster is to search the global minimum on its potential energy surface. The global minimization problem is often nondeterministic-polynomial-time (NP) hard and the number of local minima grows exponentially with the cluster size. In this article, a multi-populations multi-strategies differential evolution algorithm has been proposed to search the globally stable structure of Fe and Cr nanoclusters. The algorithm combines a multi-populations differential evolution with an elite pool scheme to keep the diversity of the solutions and avoid prematurely trapping into local optima. Moreover, multi-strategies such as growing method in initialization and three differential strategies in mutation are introduced to improve the convergence speed and lower the computational cost. The accuracy and effectiveness of our algorithm have been verified by comparing the results of Fe clusters with Cambridge Cluster Database. Meanwhile, the performance of our algorithm has been analyzed by comparing the convergence rate and energy evaluations with the classical DE algorithm. The multi-populations, multi-strategies mutation and growing method in initialization in our algorithm have been considered respectively. Furthermore, the structural growth pattern of Cr clusters has been predicted by this algorithm. The results show that the lowest-energy structure of Cr clusters contains many icosahedra, and the number of the icosahedral rings rises with increasing size. [ABSTRACT FROM AUTHOR]

Owing to its broad potential applications, nanostructured ceria has been subject of intense investigation in the past few decades. Experiments have demonstrated that various material properties of the nanostructured ionic solids including ceria vary with the feature size. Here, we present a theoretical study of the size effects on the composition, defect concentrations and stresses in free-standing nanoparticles of nonstoichiometric ionic solids. To this end, a continuum model is developed which accounts for the highly nonlinear coupling between mechanical, chemical and electrical driving forces, and their effects on the thermodynamic equilibrium of the defect species. It is demonstrated that the model, once applied to the case of ceria, predicts size-dependent defect concentrations and surface stresses. It is further shown that the theoretical predictions of the size effects on the composition and lattice parameter are in good agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

When the grain size in polycrystalline materials is reduced to the nanometer length scale (nanocrystallinity), observations from experiments and atomistic simulations suggest that the yield strength decreases (softening) as the grain size is decreased. This is in contrast to the Hall–Petch relation observed in larger sized grains. We incorporated grain boundary (GB) sliding and dislocation emission from GB junctions into the classical DDD framework, and recovered the smaller is weaker relationship observed in nanocrystalline materials. This current model shows that the inverse Hall–Petch behavior can be obtained through a relief of stress buildup at GB junctions from GB sliding by emitting dislocations from the junctions. The yield stress is shown to vary with grain size, d , by a d 1 / 2 relationship when grain sizes are very small. However, pure GB sliding alone without further plastic accomodation by dislocation emission is grain size independent. [ABSTRACT FROM AUTHOR]

We study irreversible ultrafast dynamics caused by interaction of a semiconductor quantum-dot-metallic-nanorod system with an infrared laser field. We show that when this system supports exciton-plasmon coupling, by just varying the amplitude of this laser for a short period of time (several nanoseconds), one can decide the instance when the plasmon field of the nanorod becomes significant and its duration. This is done by showing that a sudden rise in the amplitude of the infrared laser (positive pulse) can induce irreversible transition from one of the collective molecular states of this system to another, making the plasmon field significant. When this amplitude reduces for a short period of time (negative pulse), the system returns back to its initial state, suppressing this field. We provide a detailed description of how, depending on the location, the infrared-induced dynamics can lend itself to different time-dependent plasmon fields around the nanorod. Our results show that at a given moment of time at each location we can have dramatically different types of dynamics for the phase and amplitude of the plasmon field. Using these we show that a quantum-dot-metallic-nanoparticle system can act as an all-optical and logic gate. [ABSTRACT FROM AUTHOR]

We conducted uniaxial compression of single crystalline Mg alloy, AZ31 (Al 3 wt% and Zn 1 wt%) nanopillars with diameters between 300 and 5000 nm with two distinct crystallographic orientations: (1) along the [0001] c -axis and (2) at an acute angle away from the c -axis, nominally oriented for basal slip. We observe single slip deformation for sub-micron samples nominally oriented for basal slip with the deformation commencing via a single set of parallel shear offsets. Samples compressed along the c -axis display an increase in yield strength compared to basal samples as well as significant hardening with the deformation being mostly homogeneous. We find that the “smaller is stronger” size effect in single crystals dominates any improvement in strength that may have arisen from solid solution strengthening. We employ 3D-discrete dislocation dynamics (DDD) to simulate compression along the [0001] and [ 11 2 ¯ 2 ] directions to elucidate the mechanisms of slip and evolution of dislocation microstructure. These simulations show qualitatively similar stress-strain signatures to the experimentally obtained stress–strain data. Simulations of compression parallel to the [ 11 2 ¯ 2 ] direction reveal the activation and motion of only 〈 a 〉-type dislocations and virtually no dislocation junction formation. Computations of compression along [0001] show the activation and motion of both 〈 c + a 〉 and 〈 a 〉 dislocations along with a significant increase in the formation of junctions corresponding to the interaction of intersecting pyramidal planes. Both experiments and simulation show a size effect, with a differing exponent for basal and pyramidal slip. We postulate that this anisotropy in size effect is a result of the underlying anisotropic material properties only. We discuss these findings in the context of the effective resolved shear stress relative to the unit Burgers vector for each type of slip, which reveal that the mechanism that governs size effect in this Mg-alloy is equivalent in both orientations. [ABSTRACT FROM AUTHOR]

Pt–Pd alloy nanoparticles, as potential catalyst candidates for new-energy resources such as fuel cells and lithium ion batteries owing to their excellent reactivity and selectivity, have aroused growing attention in the past years. Since structure determines physical and chemical properties of nanoparticles, the development of a reliable method for searching the stable structures of Pt–Pd alloy nanoparticles has become of increasing importance to exploring the origination of their properties. In this article, we have employed the particle swarm optimization algorithm to investigate the stable structures of alloy nanoparticles with fixed shape and atomic proportion. An improved discrete particle swarm optimization algorithm has been proposed and the corresponding scheme has been presented. Subsequently, the swap operator and swap sequence have been applied to reduce the probability of premature convergence to the local optima. Furthermore, the parameters of the exchange probability and the ‘particle’ size have also been considered in this article. Finally, tetrahexahedral Pt–Pd alloy nanoparticles has been used to test the effectiveness of the proposed method. The calculated results verify that the improved particle swarm optimization algorithm has superior convergence and stability compared with the traditional one. [ABSTRACT FROM AUTHOR]

The effect of spatial correlations on the Purcell effect in a bidimensional dispersion of resonant nanoparticles is analyzed. We perform extensive calculations on the fluorescence decay rate of a point emitter embedded in a system of nanoparticles statistically distributed according to a simple two-dimensional lattice-gas model near the critical point. For short-range correlations (high temperature thermalization) the Purcell factors present a long-tailed statistic which evolves towards a bimodal distribution when approaching the critical point where the spatial correlation length diverges. Our results suggest long-range correlations as a possible origin of the large fluctuations of experimental decay rates in disordered metal films. [ABSTRACT FROM AUTHOR]

We investigate the coherent control of the quantum optical properties of a quantum dot coupled to a metallic nanoparticle using a photon Green's function method, which is based on the exact quantization of the electromagnetic fields in a dissipative medium. The properties of the spontaneous emission spectra of such a system are studied in detail with and without involving the coherent field. The Rabi splitting effect in the spectrum emitted by the quantum dot under particular conditions is predicted for different sizes of the metal nanoparticles. We show that the spontaneous emission spectra of the transition coupled to surface plasmons may be further modified by adjusting the external coherent control on the adjacent transitions. Furthermore, the pronounced oscillatory behavior for the quantum-dot dynamics is demonstrated with the presence of the metal nanoparticle by the non-Markovian treatment. Our results may have potential applications in plasmonic-based quantum manipulation. [ABSTRACT FROM AUTHOR]

We consider the integration of quantum emitters into a negative permeability metamaterial design in order to introduce tunability as well as nonlinear behavior. The unit cell of our metamaterial is a ring of metamolecules, each consisting of a metal nanoparticle and a two-level semiconductor quantum dot (QD). Without the QDs, the ring of the unit cell is known to act as an artificial optical magnetic resonator. By adding the QDs we show that a Fano interference profile is introduced into the magnetic field scattered from the ring. This induced interference is shown to cause an appreciable effect in the collective magnetic resonance of the unit cell. We find that the interference provides a means to tune the response of the negative permeability metamaterial. The exploitation of the QD's inherent nonlinearity is proposed to modulate the metamateriaľs magnetic response with a separate control field. [ABSTRACT FROM AUTHOR]

The interactions between polarized Laguerre-Gaussian beams and clusters of metallic nanoparticles have been investigated by means of the nonlinear multiple scattering method. The near-field phase singularities and vorticity in the longitudinal component of the second-harmonic field have been discussed. We have found that the phase profile of the second-harmonic field is twice as many helicities as that of the fundamental frequency field. The spin-based second-harmonic generations--spatial splitting of spin states and spin-Hall effect of the second-harmonic field--have been observed. A class of spin-based second-harmonic generation devices is anticipated. [ABSTRACT FROM AUTHOR]

• Transparent synaptic RRAM device with ALD-based TiN-NPs was fabricated. • HfAlO/TiO x N y interface controls the formation of the conductive filament. • Applying both increasing and identical pulse amplitudes, stable P/D was achieved. • STDP and SRDP learning rules are implemented depending on the pulse timing and frequency. • UV-induced change in currents predicted the formation of ionized oxygen defects. Resistive switching behavior of sandwiched HfAlO/TiN-NP/HfAlO switching layer demonstrated in this work. Stable 103 DC switching cycles achieved after incorporation of TiN-NPs, which were partially oxidized to form TiO x N y confirmed by X-ray photoelectron spectroscopy. The experiment predicted that TiO x N y /HfAlO interface acts as a weak spot and facilitated the rapture and formation of the conductive filaments. Also, gradual switching behavior between low resistance state and high resistance state improved after introducing atomic layer deposited TiN-NPs into the switching layer. Several synaptic properties have been studied, including potentiation/depression under different pulse schemes, spike-time-dependent plasticity, spike-rate-dependent plasticity at the frequency of 2 Hz to 200 Hz, and short-term plasticity under different pulse amplitudes. These properties demonstrated that ITO/ HfAlO/TiN-NP/HfAlO/ITO RRAM device is suitable for the neuromorphic application. Light-induced modulation of increasing current and relaxation behavior using a 405 nm laser source further confirms the possibility for light-induced random access memory devices. [ABSTRACT FROM AUTHOR]

We theoretically study a method for all-optical delay of images based on backward four-wave mixing in composites containing metal nanoparticles. In this approach a delayed phase-conjugate probe pulse is generated by the interaction of two counterpropagating pump beams and a noncollinear shaped probe pulse in the nanocomposite. The fractional delay and the reflectivity for the phase-conjugate signal pulses are studied as functions of the input pump intensity. It is shown that this scheme can be used for delayed imaging combined with the elimination of optical diffraction. The advantages of this method include miniaturized design, tunable wavelength range up to the telecommunication range, and wide bandwidth. [ABSTRACT FROM AUTHOR]

We explore the entanglement generation between two dipole emitters via a hybrid photonic-plasmonic resonant structure which consists of two metal nanoparticles (MNPs) and a high-g whispering-gallery-mode (WGM) microcavity. Because the coupling strength between the dipole emitter and the cavity can be substantially enhanced with the help of MNPs and maintained by the WGM cavity, the maximum entanglement plateau between two dipole emitters can be deterministically created even in the presence of the spontaneous emission of the dipole emitters and the decay induced by the microcavity and MNPs. The width of the plateau depends on the coupling strengths (or the radii of the MNPs) and the initial state, but is insensitive to the dipole-cavity detuning. These results are useful in real experiments. [ABSTRACT FROM AUTHOR]

We present theoretical investigations of high-order-harmonic generation (HHG) resulting from the interaction of noble gases with localized surface plasmons. These plasmonic near-fields are produced when a metal nanoparticle is subject to a few-cycle laser pulse. The enhanced field, which largely depends on the geometrical shape of the metallic nanostructure, has a strong spatial dependency. We demonstrate that the strong nonhomogeneity of this laser field plays an important role in the HHG process and leads to a significant increase of the harmonic-cutoff energy. In order to understand and characterize this feature, we include the functional form of the laser electric field obtained from recent attosecond streaking experiments [F. Süßmann and M. F. Kling, Proc. SPIE 8096, 80961C (2011)] in the time-dependent Schrödinger equation. By performing classical simulations of the HHG process we show consistency between them and the quantum-mechanical predictions. These allow us to understand the origin of the extended harmonic spectra as a selection of particular trajectory sets. The use of metal nanoparticles is an alternate way of generating coherent XUV light with a laser field whose characteristics can be synthesized locally. [ABSTRACT FROM AUTHOR]

We present theoretical studies of above-threshold ionization (ATI) produced by spatially inhomogeneous fields. This kind of field appears as a result of the illumination of plasmonic nanostructures and metal nanoparticles with a short laser pulse. We use the time-dependent Schrödinger equation in reduced dimensions to understand and characterize the ATI features in these fields. It is demonstrated that the inhomogeneity of the enhanced plasmonic field plays an important role in the ATI process and it produces appreciable modifications to the energy-resolved photoelectron spectra. In fact, our numerical simulations reveal that high-energy electrons can be generated. Specifically, using a linear approximation for the spatial dependence of the enhanced plasmonic field and with a near-infrared laser with intensities in the mid 1014W/cm2 range, we show it is possible to drive electrons with energies in the near-keV regime. Furthermore, we study how the carrier envelope phase influences the emission of ATI photoelectrons for few-cycle pulses. Our quantum mechanical calculations are supported by their classical counterparts. [ABSTRACT FROM AUTHOR]

We investigate an array of metal nanoparticles as a channel for nanophotonic quantum communication and the generation of quantum plasmonic interference. We consider the transfer of quantum states, including single qubits as plasmonic wave packets, and highlight the necessity of a quantum-mechanical description by comparing the predictions of quantum theory with those of classical electromagnetic theory. The effects of loss in the metal are included, thus putting our investigation into a practical setting and enabling the quantification of the performance of realistic nanoparticle arrays as plasmonic quantum channels. We explore the interference of single plasmons, finding nonlinear absorption effects associated with the quantum properties of the plasmon excitations. This work highlights the benefits and drawbacks of using nanophotonic periodic systems for quantum plasmonic applications, such as quantum communication and the generation of quantum interference. [ABSTRACT FROM AUTHOR]

Fluorescence, resonance, and off-resonance Raman spectroscopy are all precise and versatile techniques for indentifying small quantities of chemical and biological substances. One way to improve the sensitivity and specificity of these measurement techniques is to use enhancement of optical fields in the vicinity of metal nanoparticles. The degree of enhancement, however, is drastically different as Raman enhancement of 10 orders of magnitude or more has been consistently measured in experiment, while the enhancement of the seemingly similar process of fluorescence is typically far more modest. While resonance Raman scattering has the advantages of higher sensitivity and specificity when compared with the ordinary, nonresonant Raman process, its plasmon enhancement is far less spectacular. In fact, both fluorescence and resonance Raman measurements are subject to quenching when the molecule is placed too close to the metal surface. Such an effect, however, is completely absent from the normal nonresonant Raman process. In this work, we present an analytical model that reveals the physics behind the strikingly different orders of magnitude in enhancement that have been observed, provide a fundamental explanation for the quenching effect observed in fluorescence and resonance Raman but not in normal Raman, establish limits for attainable enhancement, and outline the path to optimization of all three processes. [ABSTRACT FROM AUTHOR]

We propose a hybrid photonic-plasmonic resonant structure which consists of a metal nanoparticle (MNP) and a whispering-gallery-mode (WGM) microcavity. It is found that the hybrid mode enables a strong interaction between the light and matter, and the single-atom cooperativity is enhanced by more than two orders of magnitude compared to that in a bare WGM microcavity. This improvement originates from two aspects: the MNP offers a highly enhanced local field in the vicinity of an emitter, and, interestingly, the high-Q property of WGMs can be maintained in the presence of the MNP. Thus the present system has advantages over a single microcavity or a single MNP, and holds potential in quantum optics, nonlinear optics, and highly sensitive biosensing. [ABSTRACT FROM AUTHOR]

It's been a big year for low-energy nuclear reactions. LENRs, as they're known, are a fringe research topic that some physicists think could explain the results of an infamous experiment nearly 30 years ago that formed the basis for the idea of cold fusion. That idea didn't hold up, and only a handful of researchers around the world have continued trying to understand the mysterious nature of the inconsistent, heat-generating reactions that had spurred those claims. [ABSTRACT FROM AUTHOR]

The article presents comments on miscellaneous topics by "New Scientist" readers. Topics include an article on middle age in the March 10, 2012 issue, the link between metallic nanoparticles and foot pain, and a book titled "How Many Elephants in a Blue Whale?," by Marcus Weeks that asserts a marathon is equal to 85 5-minute walks (FMWs).

The article discusses a collaborative project for the development of opthothermoelectric nanotweezers (OTENTs) to improve particle-trapping efficiency using simple optics with tunable working wavelength and low power consumption. It illustrates the operation of OTENT, which consists surface modification of a metal nanoparticle through cetyltrimethylammonium chloride. Comments from project leader Yuebing Zheng on the potential of OTENT in nanophotonics and colloidal particle science.

The article reports on the study by researchers at the University of Oxford, University of Manchester, and Macquarie University, published in the journal "Nano Letters" translating a biological technique to uncover atomic-scale chemistry in metal nanoparticles.

We theoretically study the resonance fluorescence spectrum of a three-level quantum emitter coupled to a spherical metallic nanoparticle. We consider the case in which the quantum emitter is driven by a single laser field along one of the optical transitions. We show that the development of the spectrum depends on the relative orientation of the dipole moments of the optical transitions in relation to the metal nanoparticle. In addition, we demonstrate that the location and width of the peaks in the spectrum are strongly modified by the exciton-plasmon coupling and the laser detuning, allowing one to achieve a controlled strongly subnatural spectral line. A strong antibunching of the fluorescent photons along the undriven transition is also obtained. Our results may be used for creating a tunable source of photons which could be used for a probabilistic entanglement scheme in the field of quantum information processing. [ABSTRACT FROM AUTHOR]

We present a theoretical investigation of high-order-harmonic generation (HHG) via bichromatic plasmonic near fields with metal nanoparticles. Bichromatic plasmonic near fields, which depend on temporal waveform synthesis, are generated when a metallic nanoparticle subjected to a moderate-intensity (<1012W/cm²) bichromatic few-cycle pulse. By means of a windowed Fourier transform of the time-dependent acceleration, we show that the differences in energies and level crossing between the adiabatic states of a two-level Hamiltonian are responsible for the cutoff energy of harmonics. Thus, we can manipulate the adiabatic states, and consequently the HHG spectra, by means of the bichromatic plasmonic near fields. In contrast to the case of a monochromatic field alone, a significant cutoff extension can be achieved via optimization of the bichromatic few-cycle pulse. Moreover, the supercontinuum in the bichromatic field shows a higher energy spectrum along with a broader bandwidth, which is beneficial for the efficient generation of broadband-isolated ultrashort extreme ultraviolet pulses from few-cycle laser fields. [ABSTRACT FROM AUTHOR]

The article discusses research on the use magnets to control brain activity in mice. It references a study by Polina Anikeeva et al and published in the March 12, 2015 online issue of "Science." Topics covered include the effectiveness of deep brain stimulation as treatment for disorders like Parkinson's disease, the technical challenge of injecting metal nanoparticles into the human brain and controlling them with magnetic fields, and the ability of nanoparticles to destroy cancer tumors.