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Violeta Lazic, Roberta Fantoni, Antonio Palucci, Massimiliano Ciaffi
We studied changes in laser-induced breakdown spectroscopy (LIBS) signal intensity with the thickness of a liquid layer placed on a solid substrate, where an easily evaporating methanol sample was used. For a certain optimal liquid film thickness we obtained a manifold increase of the LIBS signal from methanol. Progressive liquid film thinning leads to a reduction and a successive disappearance of laser-induced splashes; the latter condition drastically reduces the sample consumption and allows measurements to be repeated many times on a single liquid droplet...
January 1, 2017: Applied Spectroscopy
Suyash P Awate, Richard M Leahy, Anand A Joshi
Typical studies of the geometry of the cerebral cortical structure focus on either cortical folding or thickness. They rely on spatial normalization, but use cortical descriptors that are sensitive to misregistration arising from the well-known problems of partial homologies between subject brains and local optima in nonlinear registration. In contrast to these approaches, we propose a novel framework for studying the geometry of the entire cortical sheet, subsuming its folding and thickness characteristics...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
Vincent Drouard, Radu Horaud, Antoine Deleforge, Sileye Ba, Georgios Evangelidis
Head-pose estimation has many applications, such as social event analysis, human-robot and human-computer interaction, driving assistance, and so forth. Head-pose estimation is challenging because it must cope with changing illumination conditions, variabilities in face orientation and in appearance, partial occlusions of facial landmarks, as well as bounding-box-to- face alignment errors. We propose tu use a mixture of linear regressions with partially-latent output. This regression method learns to map high-dimensional feature vectors (extracted from bounding boxes of faces) onto the joint space of head-pose angles and bounding-box shifts, such that they are robustly predicted in the presence of unobservable phenomena...
January 16, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Mehrtash Harandi, Mathieu Salzmann, Richard Hartley
Representing images and videos with Symmetric Positive Definite (SPD) matrices, and considering the Riemannian geometry of the resulting space, has been shown to yield high discriminative power in many visual recognition tasks. Unfortunately, computation on the Riemannian manifold of SPD matrices -especially of high-dimensional ones- comes at a high cost that limits the applicability of existing techniques. In this paper, we introduce algorithms able to handle high-dimensional SPD matrices by constructing a lower-dimensional SPD manifold...
January 18, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
Ken H M Ho, Vico C L Chiang, Doris Leung
AIMS: This paper discusses the ways researchers may become open to manifold interpretations of lived experience through thematic analysis that follows the tradition of hermeneutic phenomenology. BACKGROUND: Martin Heidegger's thinking about historical contexts of understandings and the notions of 'alētheia' and 'techne' disclose what he called meaning of lived experience, as the 'unchanging Being of changing beings'. While these notions remain central to hermeneutic phenomenological research, novice phenomenologists usually face the problem of how to incorporate these philosophical tenets into thematic analysis...
January 19, 2017: Journal of Advanced Nursing
Bo Peng, Niranjan Govind, Edoardo Aprà, Michael Klemm, Jeff R Hammond, Karol Kowalski
In this paper we apply the equation-of-motion coupled cluster (EOM-CC) methods in the studies of the vertical ionization potentials (IPs) and electron affinities (EAs) for a series of single walled carbon nanotubes (SWCNT). The EOM-CC formulations for IPs and EAs employing excitation manifolds spanned by single and double excitations (IP/EA-EOM-CCSD) are used to study the IPs and EAs of the SWCNTs as a func- tion of the nanotube length. Several armchair nanotubes corresponding to C20nH20 models with n = 2 - 6 have been used in benchmark calculations...
January 19, 2017: Journal of Physical Chemistry. A
Laia Davin, Ross McLellan, Alberto Hernán-Gómez, William Clegg, Alan R Kennedy, Maria Mertens, Iain A Stepek, Eva Hevia
Using a specially designed magnesium metallating manifold, combining kinetically activated TMP amide base with a sterically amplified β-diketiminate ligand, this study has established a new regioselective strategy for magnesiation of challenging N-heterocyclic molecules. The broad scope of the approach is illustrated through reactions of pyrazine, triazoles and substituted pyridines by isolation and structural elucidation of their magnesiated intermediates.
January 19, 2017: Chemical Communications: Chem Comm
Maik Pflugradt, Kai Geissdoerfer, Matthias Goernig, Reinhold Orglmeister
Automatic detection of ectopic beats has become a thoroughly researched topic, with literature providing manifold proposals typically incorporating morphological analysis of the electrocardiogram (ECG). Although being well understood, its utilization is often neglected, especially in practical monitoring situations like online evaluation of signals acquired in wearable sensors. Continuous blood pressure estimation based on pulse wave velocity considerations is a prominent example, which depends on careful fiducial point extraction and is therefore seriously affected during periods of increased occurring extrasystoles...
January 14, 2017: Sensors
Pooria Farahani, Wilhelm Josef Baader
Determination of the ground and excited state unimolecular decomposition mechanisms of 1,2-dioxetanedione gives a level of insight into bimolecular decomposition reactions of this kind for which some experimental results are reported. Although, a few studies have put some effort to describe a biradical mechanism of this decomposition, there is still no systematic study which proves an existence of a biradical character. In the present study, state-of-the-art high-level multistate multiconfigurational reference second-order perturbation theory calculations are performed to describe the reaction mechanism of 1,2-dioxetanedione, in detail...
January 17, 2017: Journal of Physical Chemistry. A
Andrei E Tarkhov, Leonid I Menshikov, Peter O Fedichev
Gompertz empirical law of mortality is often used in practical research to parametrize survival fraction as a function of age with the help of just two quantities: the Initial Mortality Rate (IMR) and the Gompertz exponent, inversely proportional to the Mortality Rate Doubling Time (MRDT). The IMR is often found to be inversely related to the Gompertz exponent, which is the dependence commonly referred to as Strehler-Mildvan (SM) correlation. In this paper, we address fundamental uncertainties of the Gompertz parameters inference from experimental Kaplan-Meier plots and show, that a least squares fit often leads to an ill-defined non-linear optimization problem, which is extremely sensitive to sampling errors and the smallest systematic demographic variations...
January 16, 2017: Journal of Theoretical Biology
Jiahao Pang, Gene Cheung
Inverse imaging problems are inherently underdetermined, and hence it is important to employ appropriate image priors for regularization. One recent popular prior- the graph Laplacian regularizer-assumes that the target pixel patch is smooth with respect to an appropriately chosen graph. However, the mechanisms and implications of imposing the graph Laplacian regularizer on the original inverse problem are not well understood. To address this problem, in this paper we interpret neighborhood graphs of pixel patches as discrete counterparts of Riemannian manifolds and perform analysis in the continuous domain, providing insights into several fundamental aspects of graph Laplacian regularization for image denoising...
January 11, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Xiaojuan Dai, Di Song, Kunhui Liu, Hongmei Su
5-Iodouracil (5-IU) can be integrated into DNA and acts as a UV sensitive chromophore suitable for probing DNA structure and DNA-protein interactions based on the photochemical reactions of 5-IU. Here, we perform joint studies of time-resolved Fourier transform infrared (TR-FTIR) spectroscopy and ab initio calculations to examine the state-specific photochemical reaction mechanisms of the 5-IU. The fact that uracil (U) is observed in TR-FTIR spectra after 266 nm irradiation of 5-IU in acetonitrile and ascribed to the product of hydrogen abstraction by the uracil-5-yl radical (U·) provides experimental evidence for the C-I bond homolysis of 5-IU...
January 14, 2017: Journal of Chemical Physics
Tobias Meinert, Benjamin Alexander Gutwein, Alexander Rohrbach
Light-sheet microscopy enables fast 3D, high-contrast imaging in biology and colloidal sciences. Recently, the controlled transport of living embryos or small colloids through stable glass capillaries is manifold interesting. Although they hardly impair the sample, glass capillaries spoil the image by generating significant aberrations of the illumination and detection light. Here, we analyze the deflection of illuminating Bessel beams at the capillary by k-spectral shifting, and correct for it by a beam deflector...
January 15, 2017: Optics Letters
Chong Cheng, Shuang Li, Arne Thomas, Nicholas A Kotov, Rainer Haag
Functional graphene nanomaterials (FGNs) are fast emerging materials with extremely unique physical and chemical properties and physiological ability to interfere and/or interact with bioorganisms; as a result, FGNs present manifold possibilities for diverse biological applications. Beyond their use in drug/gene delivery, phototherapy, and bioimaging, recent studies have revealed that FGNs can significantly promote interfacial biointeractions, in particular, with proteins, mammalian cells/stem cells, and microbials...
January 11, 2017: Chemical Reviews
Alexandra Schischko, Hongjun Ren, Nikolaos Kaplaneris, Lutz Ackermann
Methods for the chemoselective modification of amino acids and peptides are powerful techniques in biomolecular chemistry. Among other applications, they enable the total synthesis of artificial peptides. In recent years, significant momentum has been gained by exploiting palladium-catalyzed cross-coupling for peptide modification. Despite major advances, the prefunctionalization elements on the coupling partners translate into undesired byproduct formation and lengthy synthetic operations. In sharp contrast, we herein illustrate the unprecedented use of versatile ruthenium(II)carboxylate catalysis for the step-economical late-stage diversification of α- and β-amino acids, as well as peptides, through chemo-selective C-H arylation under racemization-free reaction conditions...
January 11, 2017: Angewandte Chemie
Ling Ma, Xiabi Liu, Yan Gao, Yanfeng Zhao, Xinming Zhao, Chunwu Zhou
This paper proposes a new method of content based medical image retrieval through considering fused, context-sensitive similarity. Firstly, we fuse the semantic and visual similarities between the query image and each image in the database as their pairwise similarities. Then, we construct a weighted graph whose nodes represent the images and edges measure their pairwise similarities. By using the shortest path algorithm over the weighted graph, we obtain a new similarity measure, context-sensitive similarity measure, between the query image and each database image to complete the retrieval process...
January 6, 2017: Journal of Biomedical Informatics
Pew-Thian Yap, Bin Dong, Yong Zhang, Dinggang Shen
In diffusion MRI, the outcome of estimation problems can often be improved by taking into account the correlation of diffusion-weighted images scanned with neighboring wavevectors in q-space. For this purpose, we propose in this paper to employ tight wavelet frames constructed on non-flat domains for multi-scale sparse representation of diffusion signals. This representation is well suited for signals sampled regularly or irregularly, such as on a grid or on multiple shells, in q-space. Using spectral graph theory, the frames are constructed based on quasi-affine systems (i...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
M Brouard, S D S Gordon, A Hackett Boyle, C G Heid, B Nichols, V Walpole, F J Aoiz, S Stolte
The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging...
January 7, 2017: Journal of Chemical Physics
Qiongdi Zhang, Ming Zhang, Lyas Deghlaf, Jeanne Bataille, Jean Gamby, Anne-Marie Haghiri-Gosnet, Antoine Pallandre
Microfluidics has emerged following the quest for scale reduction inherent to micro and nanotechnologies. By definition, microfluidics manipulates fluids in small channels with dimensions of tens to hundreds of micrometers. Recently, microfluidics has been greatly developed and its influence extends not only the domains of chemical synthesis, bioanalysis and medical researches but also optics and information technology. In this review article, we will shortly discuss an enlightening analogy between electrons transport in electronics and fluids transport in microfluidic channels...
January 6, 2017: Electrophoresis
Otoniel Denis-Alpizar, Raymond J Bemish, Markus Meuwly
The NO(X(2)Π) + N((4)S) reaction which occurs entirely in the triplet manifold of N2O is investigated using quasiclassical trajectories and quantum simulations. Fully-dimensional potential energy surfaces for the (3)A' and (3)A'' states are computed at the MRCI+Q level of theory and are represented using a reproducing kernel Hilbert space. The N-exchange and N2-formation channels are followed by using the multi-state adiabatic reactive molecular dynamics method. Up to 5000 K these reactions occur predominantly on the N2O (3)A'' surface...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
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