In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains, Escherichia coli DH5α, Micrococcus luteus and Staphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications. Biswarup Saha and Jaydeep Bhattacharya authors contributed equally.     

Dissipative based adaptive reliable sampled-data control of time-varying delay systems

This paper is concerned with the problem of dissipative based adaptive reliable controller for a class of time delay systems subject to actuator failures and time-varying sampling with a known upper bound on the sampling intervals. By constructing a proper Lyapunov-Krasovskii functional which fully uses the available information about the actual sampling pattern and time delays, a new set of sufficient conditions is derived to obtain the required result. Then, a dissipative based adaptive sampled-data controller is designed such that the resulting closed-loop system is reliable in the sense that it is asymptotically stable and has the prescribed dissipative performance under given constraints. The existence condition of the desired dissipative based adaptive reliable sampled-data controller is obtained in terms of linear matrix inequalities. Further, the performance of the proposed controller is implemented on a liquid propellant rocket motor with a pressure feeding system model. The simulation results show the effectiveness and better performance of the proposed adaptive reliable sampled-data controller over conventional reliable controller.     

Rotational sandpile models: A finite size scaling study

Nontrivial critical behaviour is observed in equilibrium lattice statistical models under rotational constraint. Effect of rotational constraint on lattice statistical models at out of equilibrium situation is important to study. Critical properties of non-equilibrium steady state of sandpile models are studied under rotational constraint via finite size scaling (FSS) analysis. Not only FSS is found to be valid for a wide range of rotational sandpile models but also they are found to belong to the same universality class.     

Neuropsychological correlates of ADHD symptoms in preschoolers.

The authors examined the neuropsychological status of 22 preschoolers at risk for attention-deficit/hyperactivity disorder (ADHD) and 50 matched control children, using measures of nonverbal working memory, perceptual and motor inhibition, and memory for relative time. All tasks included paired control conditions, which allowed for the isolation of discrete executive function constructs. Group differences were evident on several measures of neuropsychological functioning; however, after accounting for nonexecutive abilities, no deficits could be attributed to specific functions targeted by the tasks. Performance on executive measures was not related to objective indices of activity level or ratings of ADHD symptoms. Yet, the fact that at-risk preschoolers were highly symptomatic casts doubt on whether executive function deficits and/or frontostriatal networks contribute etiologically to early behavioral manifestations of ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A genetic approach for efficient outlier detection in projected space

In this paper we present a genetic solution to the outlier detection problem. The essential idea behind this technique is to define outliers by examining those projections of the data, along which the data points have abnormal or inconsistent behavior (defined in terms of their sparsity values). We use a partitioning method to divide the data set into groups such that all the objects in a group can be considered to behave similarly. We then identify those groups that contain outliers. The algorithm assigns an ‘outlier-ness’ value that gives a relative measure of how strong an outlier group is. An evolutionary search computation technique is employed for determining those projections of the data over which the outliers can be identified. A new data structure, called the grid count tree (GCT), is used for efficient computation of the sparsity factor. GCT helps in quickly determining the number of points within any grid defined over the projected space and hence facilitates faster computation of the sparsity factor. A new crossover is also defined for this purpose. The proposed method is applicable for both numeric and categorical attributes. The search complexity of the GCT traversal algorithm is provided. Results are demonstrated for both artificial and real life data sets including four gene expression data sets.     

Powder profile studies in electrodeposited cuprous oxide films

Thin films of copper oxide have been electrodeposited cathodically on copper substrates at room temperature. The deposited films have been characterized by X-ray diffraction and scanning electron microscopy. XRD showed the formation of crystalline cuprous oxide (Cu₂O). The XRD peaks are found to be shifted towards lower angle with narrowing of the profiles and the lattice parameter increases with annealing temperature. Scanning electron micrographs showed the formation of localized grain growth region which may be due to the non-uniform deposition of the films. The X-ray diffraction line broadening analysis of the as deposited as well as annealed films have been studied in order to evaluate the microstructural parameters which characterize the microstructural changes. The microstructural parameters like coherent domain size, RMS microstrain and dislocation density have been calculated using Warren-Averbach (Fourier) for multiple order, integral breadth (single and multiple line) and Williamson–Hall plot. The results of analysis obtained by different methods have been compared. The coherent domain size and RMS strain are not found to change appreciably with the increase of film thickness (4–13 μm). The optimum pH value of the electrolytic solution to deposit the films is found to lie in the range 9.2–9.3 where the strain variation is small compared to other pH values. The values of crystallite size and strains obtained by Warren–Averbach method and integral breadth method are comparable. However, Williamson–Hall plot overestimates the values of these two parameters. It is found that the crystallite size increases and RMS strain decreases with the increase of annealing temperature. The dislocation density is also found to decrease with annealing temperature.     

Syntheses and applications of Mn-doped II-VI semiconductor nanocrystals

Luminescent Mn-doped II-VI semiconductor nanocrystals have been intensively investigated over the last ten years. Several semiconductor host materials such as ZnS, CdS, and ZnSe have been used for Mn-doped nanocrystals with different synthetic routes and surface passivation. Beyond studies of their fundamental properties including photoluminescence and size, these luminescent nanocrystals have now been tested for practical applications such as electroluminescent displays and biological labeling agents (biomarkers). Here, we first review ZnS:Mn, CdS:Mn/ZnS core/shell, and ZnSe:Mn nanocrystal systems in terms of their synthetic chemistries and photoluminescent properties. Second, based on ZnS:Mn and CdS:Mn/ZnS core/shell nanocrystals as electroluminescent components, direct current electroluminescent devices having a hybrid organic/inorganic multilayer structure are reviewed. Highly luminescent and photostable CdS:Mn/ZnS nanocrystals can further be used as the luminescent biomarkers and some preliminary results are also discussed here.     

Effect of Hyperbolic Band Structure on the Energy Loss Rate of Hot Electrons with Non-equilibrium Phonon Distribution in the Extreme Quantum Limit at Low Temperatures in n-Hg0.8Cd0.2Te

The energy loss rate of hot electrons with the non-equilibrium phonons in narrowgap semiconductors with hyperbolic band structures has been investigated in the extreme quantum limit condition in the low temperature region. The calculation is done for n-Hg_0.8Cd_0.2Te sample considering electron scattering by acoustic phonons via piezoelectric coupling to be the dominant loss mechanism. The value of the energy loss rate with hyperbolic band is compared with the results of parabolic and non-parabolic band structures and at the same time all the results are also compared with the experimentally observed data. It is found that with the inclusion of hyperbolic band structure, the value of energy loss rate is found to be close to the experimental values. The dependence of energy loss rate on magnetic field and lattice temperature has been studied. Using the experimental value of the energy loss rate, the phonon life time is evaluated. The value of the phonon life time is found to be of the order of the phonon boundary relaxation time indicating that phonon boundary scattering is the dominant phonon dissipation mechanism. The dependence of the phonon life time on magnetic field, and lattice temperature has also been studied. The phonon life time is also found to decrease with increase in electron temperature.     

Entanglement-enabled interferometry using telescopic arrays

ABSTRACT

A protocol of measuring interferometric visibility function using imperfectly entangled states shared between remote telescopes is proposed. We demonstrate how quantum entanglement can be utilized to increase the baseline size of telescopic arrays thereby providing substantial enhancement to the resolution of direct-detection interferometric measurements. We demonstrate, through a comprehensive analysis, how errors in visibility measurements and in the intensity distribution of a distant object show dependence on the entanglement degree of the shared quantum resource. We analyse the feasibility of the protocol using currently available technology and identify the nature of sources that can benefit most from it.