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Emanuele Calabrò, Salvatore Magazù
The aim of this article was to study the effects of mobile phone electromagnetic waves at 1750 MHz on the Amide I and Amide II vibration bands of some proteins in bidistilled water solution by means of Fourier transform infrared (FTIR) spectroscopy and Fourier self-deconvolution (FSD) analysis. The proteins that were used for the experiment were hemoglobin, myoglobin, bovine serum albumin and lysozyme. The exposure system consisted of microwaves emitted by an operational mobile phone at the frequency at 1750 MHz at the average power density of 1 W/m(2)...
June 20, 2017: Electromagnetic Biology and Medicine
Arun Chandramohan, Nikhil Kumar Tulsian, Ganesh Srinivasan Anand
Orthosteric sites on proteins are formed typically from non-contiguous interacting sites in three dimensional space where the composite binding interaction of a biological ligand is mediated by multiple synergistic interactions of its constituent functional groups. Through these multiple interactions, ligands stabilize both the ligand binding site and the protein fold. However, relative energetic contributions of the individual contacts in these protein-ligand interactions are difficult to resolve. Deconvolution of the contributions of these various functional groups in natural inhibitors/ligand would greatly aid in iterative fragment-based drug discovery (FBDD)...
June 19, 2017: Analytical Chemistry
Erwin Garcia, Justyna Wolak-Dinsmore, Zeneng Wang, Xinmin S Li, Dennis W Bennett, Margery A Connelly, James D Otvos, Stanley L Hazen, Elias J Jeyarajah
BACKGROUND AND OBJECTIVES: Trimethylamine-N-oxide (TMAO) produced by gut microbiota metabolism of dietary choline and carnitine has been shown to be associated with increased risk of cardiovascular disease (CVD) and to provide incremental clinical prognostic utility beyond traditional risk factors for assessing a patient's CVD risk. The aim of this study was to develop an automated nuclear magnetic resonance (NMR) spectroscopy assay for quantification of TMAO concentration in serum and plasma using a high-throughput NMR clinical analyzer...
June 14, 2017: Clinical Biochemistry
Xiaoli Wei, Biyun Shi, Imhoi Koo, Xinmin Yin, Pawel Lorkiewicz, Hamid Suhail, Ramandeep Rattan, Shailendra Giri, Craig J McClain, Xiang Zhang
Stable isotope assisted metabolomics (SIAM) measures the abundance levels of metabolites in a particular pathway using stable isotope tracers (e.g., (13)C, (18)O and/or (15)N). We report a method termed signature ion approach for analysis of SIAM data acquired on a GC-MS system equipped with an electron ionization (EI) ion source. The signature ion is a fragment ion in EI mass spectrum of a derivatized metabolite that contains all atoms of the underivatized metabolite, except the hydrogen atoms lost during derivatization...
August 8, 2017: Analytica Chimica Acta
Hu Chen, Yi Zhang, Mannudeep K Kalra, Feng Lin, Yang Chen, Peixo Liao, Jiliu Zhou, Ge Wang
Given the potential risk of X-ray radiation to the patient, low-dose CT has attracted a considerable interest in the medical imaging field. Currently, the main stream low-dose CT methods include vendor-specific sinogram domain filtration and iterative reconstruction algorithms, but they need to access raw data whose formats are not transparent to most users. Due to the difficulty of modeling the statistical characteristics in the image domain, the existing methods for directly processing reconstructed images cannot eliminate image noise very well while keeping structural details...
June 13, 2017: IEEE Transactions on Medical Imaging
Ulrike I Attenberger, Jing Liu, Philipp Riffel, Johannes Budjan, Robert Grimm, Kai T Block, Stefan O Schoenberg, Xiaoying Wang, Daniel Hausmann
OBJECTIVES: Purpose of this study was to compare the quality of perfusion maps obtained from prototypical free-breathing magnetic resonance imaging (MRI) with continuous golden-angle radial sampling and iterative reconstruction (GRASP) to conventional acquisition using time-resolved angiography with interleaved stochastic trajectories (TWIST) in patients with rectal cancer. MATERIAL AND METHODS: Forty cases were included for retrospective analysis. Twenty of the patients received routine multiparametric MRI at 3 T for rectal cancer staging, including perfusion measurement with GRASP or TWIST (10 patients for each technique, including 5 prechemoradiation and 5 postchemoradiation)...
June 16, 2017: Investigative Radiology
Xanthi D Andrianou, Pantelis Charisiadis, Konstantinos Christos Makris
Abiding by the exposome paradigm, incorporation of external and internal exposure metrics using metabolomics tools is warranted to refine the etiology of type II diabetes (T2D). A small (n=51) age- and sex-matched case-control study was conducted in Cyprus coupling urinary trihalomethanes (THM) with T2D. The objectives were to: i) perform a comparative assessment of different deconvolution parameters in compound identification, and ii) evaluate the association between differentially expressed metabolites and either urinary THM or T2D status...
June 16, 2017: Journal of Proteome Research
András Sápi, András Varga, Gergely F Samu, Dorina Dobó, Koppány L Juhász, Bettina Takács, Erika Varga, Ákos Kukovecz, Zoltán Kónya, Csaba Janáky
Photoelectrochemical hydrogen evolution is a promising avenue to store the energy of sunlight in the form of chemical bonds. The recent rapid development of new synthetic approaches enables the nanoscale engineering of semiconductor photoelectrodes, thus tailoring their physicochemical properties toward efficient H2 formation. In this work, we carried out the parallel optimization of the morphological features of the semiconductor light absorber (NiO) and the cocatalyst (Pt). While nanoporous NiO films were obtained by electrochemical anodization, the monodisperse Pt nanoparticles were synthesized using wet chemical methods...
June 8, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
S Eichstädt, V Wilkens
An estimation of the measurand in dynamic metrology usually requires a deconvolution based on a dynamic calibration of the measuring system. Since deconvolution is, mathematically speaking, an ill-posed inverse problem, some kind of regularization is required to render the problem stable and obtain usable results. Many approaches to regularized deconvolution exist in the literature, but the corresponding evaluation of measurement uncertainties is, in general, an unsolved issue. In particular, the uncertainty contribution of the regularization itself is a topic of great importance, because it has a significant impact on the estimation result...
June 2017: Journal of the Acoustical Society of America
Xin Gu, Yan Yan, Scott J Novick, Amanda Kovich, Devrishi Goswami, Jiyuan Ke, M H Eileen Tan, Lili Wang, Xiaodan Li, Parker de Waal, Martin R Webb, Patrick R Griffin, H Eric Xu, Karsten Melcher
AMP-activated protein kinase (AMPK) is a central cellular energy sensor that adapts metabolism and growth to the energy state of the cell. AMPK senses the ratio of adenine nucleotides (adenylate energy charge) by competitive binding of AMP, ADP, and ATP to three sites (CBS1, CBS3, and CBS4) in its γ-subunit. Since these three binding sites are functionally interconnected, it remains unclear how nucleotides bind to individual sites, which nucleotides occupy each site under physiological conditions, and how binding to one site affects binding to the other sites...
June 14, 2017: Journal of Biological Chemistry
Victor Shokhen, Yana Miroshnikov, Gregory Gershinsky, Noam Gotlib, Chen Stern, Doron Naveh, David Zitoun
Herein, we report energy storage devices, which are based on densely packed, vertically aligned MoS2 (VA-MoS2) or planar oriented MoS2 (PO-MoS2) and compare their electrochemical performances. The VA-MoS2 films have been processed by chemical vapor deposition (CVD) to reach unprecedented micron-scale thick films while maintaining the vertical alignment for the whole thickness. The VA-MoS2 and the PO-MoS2 films form a high-performance Li-ion electrode, reaching the theoretical limits of reversible capacity for this material (800 mAh/g; twice the specific capacity of graphite)...
June 12, 2017: Scientific Reports
Carolina Rodrigues Felix, Rashmi Gupta, Sandra Geden, Jill Roberts, Priscilla Winder, Shirley A Pomponi, Maria Cristina Diaz, John K Reed, Amy E Wright, Kyle H Rohde
The dormant phenotype acquired by Mycobacterium tuberculosis (Mtb) during infection poses a major challenge in disease treatment since these bacilli are tolerant to front-line drugs. Therefore, it is imperative to find novel compounds that effectively kill dormant bacteria. By screening 4,400 marine natural product samples against dual-fluorescent Mtb under both replicating and non-replicating conditions we have identified compounds that are selectively active against dormant Mtb This validates our strategy of screening all compounds in both assays as opposed to using the dormancy model as a secondary screen...
June 12, 2017: Antimicrobial Agents and Chemotherapy
José Coelho Neto, Fernanda L C Lisboa
Viagra and Cialis are among the most counterfeited medicines in many parts of the world, including Brazil. Despite the many studies that have been made regarding discrimination between genuine and counterfeit samples, most published works do not contemplate generic and similar versions of these medicines and also do not explore excipients/adjuvants contributions when characterizing genuine and suspected samples. In this study, we present our findings in exploring ATR-FTIR spectral profiles for characterizing both genuine and questioned samples of several generic and brand-name sildenafil- and tadalafil-based tablets available on the Brazilian market, including Viagra and Cialis...
July 2017: Science & Justice: Journal of the Forensic Science Society
Jose M Carnerero, Aila Jimenez-Ruiz, Elia M Grueso, Rafael Prado-Gotor
It is well known that single-stranded DNA (ssDNA) is easily able to adsorb on citrate-capped, non-functionalized gold nanoparticles (AuNPs). However, the affinity of double-stranded DNA (dsDNA) for them is much more limited. The present work demonstrates that long dsDNA suffers from a bending conformational change when anionic nanoparticles are present in solution. A striking decrease in the persistence length of the double helix in the absence of salt is observed through dynamic light scattering (DLS), viscometric, and atomic force microscopy (AFM) methods...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
J Pitarch-Motellón, A F Roig-Navarro, J V Sancho, M Ibáñez, N Fabregat-Cabello, O J Pozo, Rosa Ventura, J I García Alonso, Pablo Rodríguez-González, Adriana González Gago, Amaia Ereño Artabe, Peter Van Eenoo, Koen Deventer, Yvette Dehnes, Sebastian Rzeppa
Three quantification methodologies, namely calibration with internal standard (Cal-IS, non-weighted), weighted calibration with internal standard (wCal-IS) and isotope pattern deconvolution (IPD) have been used for the determination of testosterone in urine by LC-MS/MS. Uncertainty has been calculated and compared for the three methodologies through intra- and inter-laboratory reproducibility assays. IPD showed the best performance for the intra-laboratory reproducibility, with RSD and combined uncertainty values below 4% and 9% respectively...
June 3, 2017: Journal of Chromatography. A
Ning Tian, Sung-Hoon Byun, Karim Sabra, Justin Romberg
This paper presents a technique for solving the multichannel blind deconvolution problem. The authors observe the convolution of a single (unknown) source with K different (unknown) channel responses; from these channel outputs, the authors want to estimate both the source and the channel responses. The authors show how this classical signal processing problem can be viewed as solving a system of bilinear equations, and in turn can be recast as recovering a rank-1 matrix from a set of linear observations. Results of prior studies in the area of low-rank matrix recovery have identified effective convex relaxations for problems of this type and efficient, scalable heuristic solvers that enable these techniques to work with thousands of unknown variables...
May 2017: Journal of the Acoustical Society of America
H C Song, Chomgun Cho, Gihoon Byun, J S Kim
The array invariant proposed for robust source localization in shallow water is based on the dispersion characteristics in ideal waveguides. It involves conventional plane-wave beamforming using a vertical array, exploiting multiple arrivals separated in beam angle and travel time, i.e., beam-time migration. The approach typically requires either a short pulse emitted by a source or the Green's function that can be estimated from a probe signal to resolve distinct multipath arrivals. In this letter, the array invariant method is extended to unknown source waveforms by extracting the Green's function via blind deconvolution...
May 2017: Journal of the Acoustical Society of America
Mayandi Sivaguru, Mohammad M Kabir, Manas Rangan Gartia, David S C Biggs, Barghav S Sivaguru, Vignesh A Sivaguru, Glenn A Fried, Gang Logan Liu, Sakthivel Sadayappan, Kimani C Toussaint
Second-harmonic generation (SHG) microscopy has gained popularity because of its ability to perform submicron, label-free imaging of noncentrosymmetric biological structures, such as fibrillar collagen in the extracellular matrix environment of various organs with high contrast and specificity. Because SHG is a two-photon coherent scattering process, it is difficult to define a point spread function (PSF) for this modality. Hence, compared to incoherent two-photon processes like two-photon fluorescence, it is challenging to apply the various PSF-engineering methods to improve the spatial resolution to be close to the diffraction limit...
June 8, 2017: Journal of Microscopy
Selva Rivas-Arancibia, Erika Rodríguez-Martínez, Isidro Badillo-Ramírez, Ulises López-González, José M Saniger
The aim of this work was to study the effect of oxidative stress on the structural changes of the secondary peptide structure of amyloid beta 1-42 (Aβ 1-42), in the dentate gyrus of hippocampus of rats exposed to low doses of ozone. The animals were exposed to ozone-free air (control group) and 0.25 ppm ozone during 7, 15, 30, 60, and 90 days, respectively. The samples were studied by: (1) Raman spectroscopy to detect the global conformational changes in peptides with α-helix and β-sheet secondary structure, following the deconvolution profile of the amide I band; and (2) immunohistochemistry against Aβ 1-42...
2017: Frontiers in Molecular Neuroscience
Francesca Sibilia, Elizabeth Grace Kehoe, Dervla Farrell, Christian Kerskens, Desmond O'Neill, Jonathan Paul McNulty, Paul Gerald Mullins, Arun Bokde
The aim of this study was to investigate the aging-related structural changes of the cingulum, one of the major components of the limbic network, which has a critical role in emotion, attention and memory. 35 healthy young adults (22.3 ± 2.7 years) and 33 healthy older adults (69.5 ± 3.5 years) were recruited. Diffusion weighted imaging data were acquired with a b-value = 2000 s/mm2, 61 diffusion directions and 4 non-weighted images. The fiber directions in each voxel were based on the constrained spherical deconvolution (CSD) model...
June 5, 2017: Brain Connectivity
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