Pure phase-encoded MRI and classification of solids

Here, the authors combine a pure phase-encoded magnetic resonance imaging (MRI) method with a new tissue-classification technique to make geometric models of a human tooth. They demonstrate the feasibility of three-dimensional imaging of solids using a conventional 11.7-T NMR spectrometer. In solid-state imaging, confounding line-broadening effects are typically eliminated using coherent averaging methods. Instead, the authors circumvent them by detecting the proton signal at a fixed phase-encode time following the radio-frequency excitation. By a judicious choice of the phase-encode time in the MRI protocol, the authors differentiate enamel and dentine sufficiently to successfully apply a new classification algorithm. This tissue-classification algorithm identifies the distribution of different material types, such as enamel and dentine, in volumetric data. In this algorithm, the authors treat a voxel as a volume, not as a single point, and assume that each voxel may contain more than one material. They use the distribution of MR image intensities within each voxel-sized volume to estimate the relative proportion of each material using a probabilistic approach. This combined approach, involving MRI and data classification, is directly applicable to bone imaging and hard-tissue contrast-based modeling of biological solids

Coherence as an indicator to discern electromagnetically induced transparency and Autler-Townes splitting

Electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS) are generally characterized and distinguished by the width of the transparency created in the absorption profile of a weak probe in presence of a strong control field. This often leads to ambiguities, as both phenomena yield similar spectroscopic signature. However, an objective method based on the AIC test offers a quantitative way to discern the two regimes when applied on the probe absorption profile. The obtained transition value of control field strength was found to be higher than the value given by pole analysis of the corresponding off-diagonal density matrix element $\rho_{13}$. By contrast, we apply the test on ground state coherence $\rho_{12}$ and the measured coherence quantifier, which yielded a distinct transition point around the predicted value also in presence of noise. Our test accurately captures the transition between the two regimes, indicating that a proper measure of coherence is essential for making such distinctions.Comment: 5 pages, 4 figure

Local Identification of Subsets of Quantum states: A Stronger Quantum Nonlocality

Nonolocality makes quantum theory nontrivially sacred and useful in the paradigm of information theoretic tasks. Apart from Bell nonlocality, which deals with measurement outcome statistics of spatially separated agents, there is also another kind of quantum nonlocality, that is associated with perfect distinguishability of quantum states by local operations and classical communication (LOCC). We propose a distributed task: perfect identification of subsets of a known set of multipartite orthogonal states by LOCC, namely, local subset identification. Failure in accomplishing this task guarantees a new notion of quantum nonlocality, viz., local subset unidentifiability. Here, we show that both local distinguishability and local markability of quantum states implies local subset identifiability, but the converse is not necessarily true. This makes local subset unidentifiability a stronger quantum nonlocal phenomenon than its predecessors -- local indistinguishability and local unmarkability. Moreover, we also present an even stronger version of local subset unidentifiablity involving more than two spatially separated parties namely, genuine local subset unidentifiability, where a given subset becomes identifiable if and only if all the parties come together in a common lab.Comment: Initial draft, New results added, Comments are welcom

Role of plant secondary metabolites in combating pest induced stress in brinjal (Solanum melongena L.)

Brinjal or eggplant (Solanum melongena L.) is known as a vegetable of diet because it contains high moisture and low calorific value. It is also a good source of antioxidants and phytonutrients. Brinjal is widely grown in the South and South-East Asian countries and is the second most important vegetable in India. It belongs to the Solanaceae family. Shoot and fruit borer (Leucinodes orbonalis) pest of brinjal is the most widespread one and it has the ability to affect any of the developmental stages of brinjal. Plants and their insect herbivores have had a long and intimate evolutionary association that has resulted in many complex interactions mediated by specialized plant metabolites like phenolics, alkaloids, terpenoids, cyanogenic glycosides etc. Frequent and excessive use of insecticides has become a common practice now which only increases the probability of resistance development and resurgence of pest. Hence to develop an effective approach to combat this pest understanding of its feeding mechanism and chemistry of its interaction with the fruit is necessary. The importance of the secondary metabolites in the field of chemical biology and in pest management is discussed in this study

Excited-state proton transfer from pyranine to acetate in methanol

Excited-state proton transfer (ESPT) of pyranine (8-hydroxypyrene-1,3,6-trisulphonate, HPTS) to acetate in methanol has been studied by steady-state and time-resolved fluorescence spectroscopy. The rate constant of direct proton transfer from pyranine to acetate (k1) is calculated to be ~1 × 109 M-1 s-1. This is slower by about two orders of magnitude than that in bulk water (8 × 1010 M-1 s-1) at 4 M acetate