bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shell bed tempestites in the Chenier Plain of Louisiana: late Holocene example and modern analogue
Authors: Williams Harry F.L. 
Published: February 2011

AbstractHurricane Ike's storm surge deposited a concentrated shell bed in the form of a series of coalescing washover fans over backshore sand and adjoining marshland in part of southwest Louisiana's Chenier Plain. The shell bed is a tempestite and has distinctive morphological, sedimentological and biogenic characteristics that provide a modern analogue to aid interpretation of older shell bed tempestites in the geological record. The shell bed has a wedge‐shaped profile that thickens landward, is about 40 m wide, up to 27 cm thick and extends several hundred metres parallel to the shore. Shells are predominantly disarticulated valves of the common bivalve Mulinia lateralis, probably reworked and transported landward from skeletal remains offshore. The shell bed has an erosional base, is bioclast supported, normally graded and has common mud rip‐up clasts. Similarities between the modern shell bed and another concentrated shell deposit, forming part of a sandy beach ridge some 1.5 km inland, suggest that the palaeo shell deposit is also a tempestite recording hurricane washover of a former shoreline 600 a ago. These findings demonstrate that the shell bed deposited by Hurricane Ike is a valuable analogue for palaeotempestological investigations and that hurricanes have likely contributed to the construction of both modern berm ridges and palaeo beach ridges on this coastal plain. Copyright © 2011 John Wiley & Sons, Ltd.
SERS activity of pulsed laser ablated silver thin films with controlled nanostructure
Authors: Fazio E. , Neri F. , D'Andrea C. , Ossi P. M. , Santo N. , Trusso S. 
Published: February 2011

AbstractThe surface‐enhanced Raman scattering (SERS) activity of silver thin films deposited by the pulsed laser ablation technique was investigated. The samples were grown in a controlled Ar atmosphere at pressures ranging between 10 and 70 Pa, and changing the number of laser pulses. Different surface morphologies, from isolated nearly spherical nanoparticles (NPs) to larger islands with smooth edges, were observed by means of scanning and transmission electron microscopies, as a function of the different deposition conditions adopted. SERS measurements were performed by soaking the samples in rhodamine 6G aqueous solutions over the concentration range between 1.0 × 10−4 and 5.0 × 10−8 M. Raman spectra were acquired using both the 632.8 and 514.5 nm excitation sources. The dependence of the SERS activity of the samples on the observed surface morphology is presented and discussed. The presence of the so called hot spots is envisaged. Copyright © 2011 John Wiley & Sons, Ltd.
Deployment to a combat zone and other risk factors for mental health‐related disability discharge from the U.S. Army: 1994–2007
Authors: Bell Nicole S. , R.Hunt Phillip , Harford Thomas C. , Kay Ashley 
Published: February 2011

AbstractCombat exposure is associated with subsequent mental health symptoms, but progression to mental health disability is unclear. Army soldiers discharged with mental health disability (n = 4,457) were compared to two matched control groups: other disability discharge (n = 8,974) and routine discharge (n = 9,128). In multivariate logistic models, odds of mental health disability discharge versus other disability and routine discharge were significantly higher for soldiers deployed to combat zones; odds ratios increased with deployment time. Prior mental health hospitalization decreased these odds, though they remained significantly elevated. Mental health hospitalization with successful treatment may facilitate better coping during deployment. The frequency of disability after mental health hospitalization suggests remaining gaps in deployment‐related mental health assessment and treatment.
Anilinolysis of reactive aryl 2,4‐dinitrophenyl carbonates: Kinetics and mechanism
Authors: Castro Enrique A. , Domecq Claudia , Santos José G. 
Published: February 2011

AbstractThe reactions of a series of anilines with phenyl 2,4‐dinitrophenyl (1), 4‐nitrophenyl 2,4‐dinitrophenyl (2), and bis(2,4‐dinitrophenyl) (3) carbonates are subjected to a kinetic investigation in 44 wt% ethanol–water, at 25.0 ± 0.1°C and an ionic strength of 0.2 M. Under amine excess pseudo‐first‐order rate coefficients (kobs) are obtained. Plots of kobs against free amine concentration at constant pH are linear, with slopes kN. The Brønsted plots (log kN vs. anilinium pKa) for the anilinolysis of 1–3 are linear, with slope (β) values of 0.52, 0.61, and 0.63, respectively. The values of these slopes and other considerations suggest that these reactions are ruled by a concerted mechanism. For these reactions, the kN values follow the reactivity sequence: 3 > 2 > 1. Namely, the reactivity increases as the number of nitro groups attached to the nonleaving group increases. Comparison of the reactions of this work with the stepwise pyridinolysis of carbonates 1–3 indicates that the zwitterionic tetrahedral intermediate (T±) formed in the pyridinolysis reactions is destabilized by the change of its pyridino moiety by an isobasic anilino group. This is attributed to the superior leaving ability from the T± intermediate of anilines, relative to isobasic pyridines, which destabilize kinetically this intermediate. The kN values for the anilinolysis of carbonates 1–3 are similar to those found in the reactions of these carbonates with secondary alicyclic amines. With the kinetic data for the anilinolysis of the title substrates and 4‐methylphenyl and 4‐chlorophenyl 2,4‐dinitrophenyl carbonates, a multiparametric equation is derived for log kN as a function of the pKa of the conjugate acids of anilines and nonleaving groups. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 191–197, 2011
Ion spectrometric detection technologies for ultra‐traces of explosives: A review
Authors: Mäkinen Marko , Nousiainen Marjaana , Sillanpää Mika 
Published: February 2011

AbstractIn recent years, explosive materials have been widely employed for various military applications and civilian conflicts; their use for hostile purposes has increased considerably. The detection of different kind of explosive agents has become crucially important for protection of human lives, infrastructures, and properties. Moreover, both the environmental aspects such as the risk of soil and water contamination and health risks related to the release of explosive particles need to be taken into account. For these reasons, there is a growing need to develop analyzing methods which are faster and more sensitive for detecting explosives. The detection techniques of the explosive materials should ideally serve fast real‐time analysis in high accuracy and resolution from a minimal quantity of explosive without involving complicated sample preparation. The performance of the in‐field analysis of extremely hazardous material has to be user‐friendly and safe for operators. The two closely related ion spectrometric methods used in explosive analyses include mass spectrometry (MS) and ion mobility spectrometry (IMS). The four requirements—speed, selectivity, sensitivity, and sampling—are fulfilled with both of these methods. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 30:940–973, 2011
Fragmentation of toxicologically relevant drugs in positive‐ion liquid chromatography–tandem mass spectrometry
Authors: Niessen W.M.A. 
Published: February 2011

AbstractThe identification of drugs and related compounds by LC–MS–MS is an important analytical challenge in several application areas, including clinical and forensic toxicology, doping control analysis, and environmental analysis. Although target‐compound based analytical strategies are most frequently applied, at some point the information content of the MS–MS spectra becomes relevant. In this article, the positive‐ion MS–MS spectra of a wide variety of drugs and related substances are discussed. Starting point was an MS–MS mass spectral library of toxicologically relevant compounds, available on the internet. The positive‐ion MS–MS spectra of ∼570 compounds were interpreted by chemical and therapeutic class, thus involving a wide variety of drug compound classes, such benzodiazepines, beta‐blockers, angiotensin‐converting enzyme inhibitors, phenothiazines, dihydropyridine calcium channel blockers, diuretics, local anesthetics, vasodilators, as well as various subclasses of anti‐diabetic, antidepressant, analgesic, and antihistaminic drugs. In addition, the scientific literature was searched for available MS–MS data of these compound classes and the interpretation thereof. The results of this elaborate study are presented in this article. For each individual compound class, the emphasis is on class‐specific fragmentation, as discussing fragmentation of all individual compounds would take far too much space. The recognition of class‐specific fragmentation may be quite informative in determining the compound class of a specific unknown, which may further help in the identification. In addition, knowledge on (class‐specific) fragmentation may further help in the optimization of the selectivity in targeted analytical approaches of compounds of one particular class. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 30:626–663, 2011
In vitro bioaccessibility and gut biotransformation of polyphenols present in the water‐insoluble cocoa fraction
Authors: Fogliano Vincenzo , Corollaro Maria Laura , Vitaglione Paola , Napolitano Aurora , Ferracane Rosalia , Travaglia Fabiano , Arlorio Marco , Costabile Adele , Klinder Annett , Gibson Glenn 
Published: February 2011

AbstractScope: Cocoa, especially the water‐insoluble cocoa fraction (WICF), is a rich source of polyphenols. In this study, sequential in vitro digestion of the WICF with gastrointestinal enzymes as well as its bacterial fermentation in a human colonic model system were carried out to investigate bioaccessibility and biotransformation of WICF polyphenols, respectively.Methods and results: The yield of each enzymatic digestion step and the total antioxidant capacity (TAC) were measured and solubilized phenols were characterized by MS/MS. Fermentation of WICF and the effect on the gut microbiota, SCFA production and metabolism of polyphenols was analyzed. In vitro digestion solubilized 38.6% of WICF with pronase and Viscozyme L treatments releasing 51% of the total phenols from the insoluble material. This release of phenols does not determine a reduction in the total antioxidant capacity of the digestion‐resistant material. In the colonic model WICF significantly increased of bifidobacteria and lactobacilli as well as butyrate production. Flavanols were converted into phenolic acids by the microbiota following a concentration gradient resulting in high concentrations of 3‐hydroxyphenylpropionic acid (3‐HPP) in the last gut compartment.Conclusion: Data showed that WICF may exert antioxidant action through the gastrointestinal tract despite its polyphenols being still bound to macromolecules and having prebiotic activity.
Retrospective estimation and correction of physiological artifacts in fMRI by direct extraction of physiological activity from MR data
Authors: Le Tuong Huu , Hu Xiaoping 
Published: February 2011

AbstractA physiological artifact reduction method based on extracting respiratory motion and cardiac pulsation directly from functional MR data is described. In fast low angle shot (FLASH), respiratory cycles are derived utilizing the phase of the center of a navigator echo, in echo‐planar imaging (EPI) from the phase of the center κ‐space point. Cardiac cycles are determined from projections obtained from the navigator echo (FLASH) and the center κ‐space line (EPI). Because direct extraction of physiological parameters eliminates the need for external monitoring, the method can be more readily implemented. Experimental results illustrate that the technique provides effective compensation for physiology‐related signal fluctuations in functional MRI and performs as well as the retrospective technique using external physiological monitoring. Key words: fMRI; motion artifacts; physiological motion; image processing.
Simultaneous magnetic resonance phase and magnitude temperature maps in muscle
Authors: Cline Harvey E. , Hynynen Kullervo , Schneider Erika , Hardy Christopher J. , Maier Stefan E. , Watkins Ronald D. , Jolesz Ferenc A. 
Published: February 2011

AbstractNoninvasive magnetic resonance temperature maps that are used to monitor thermal ablation of tissue are described. In magnetic resonance images, thermally induced proton nuclear magnetic resonance frequency shifts, and changes in the longitudinal relaxation time produce both phase and magnitude changes in the MR signal. Temperature maps with improved sensitivity are derived from the complex‐difference nuclear magnetic resonance signal. Bovine muscle specimens were heated with focused ultrasound to model thermal surgery and create a known thermal distribution to test the method. Resulting MR images acquired in 2 s produce temperature maps with 1 mm resolution and 2°C temperature sensitivity. The temperature sensitivity was increased by extending the acquisition to 5 s, by decreasing the receiver bandwidth, and increasing the echo time.
A forward‐subtraction procedure for removing hyperfine artifacts in electron paramagnetic resonance imaging
Authors: Kuppusamy Periannan , Zweier Jay L. 
Published: February 2011

AbstractThe potential for using electron paramagnetic resonance (EPR) imaging in biological applications has been limited by the lack of ideal single‐line imaging probes. The commonly used nitroxides exhibit multiple lines, causing either hyper‐fine‐based limitations in the maximum obtainable image resolution or hyperfine‐based artifacts in the reconstructed image. The application of a numerical method, based on forward‐subtraction principles for removing hyperfine artifacts in the measured projections is reported. It is demonstrated by using computer simulations, imaging of phantoms, and imaging of rat hearts, that marked enhancement in image quality and resolution can be obtained by removing the hyper‐fine‐imposed limit on the gradient magnitude and performing postacquisition corrections for removing hyperfine artifacts in the image.
Three‐Dimensional gated EPR imaging of the beating heart: Time‐resolved measurements of free radical distribution during the cardiac contractile cycle
Authors: Kuppusamy Periannan , Chzhan Michael , Wang Penghai , Zweier Jay L. 
Published: February 2011

AbstractIn vivo or ex vivo EPR imaging, EPRI, has been established as a powerful technique for determining the spatial distribution of free radicals and other paramagnetic species in living organs and tissues. While instrumentation capable of performing EPR imaging of free radicals in whole tissues and isolated organs has been previously reported, it was not possible to image rapidly moving organs such as the beating heart Therefore instrumentation was developed to enable the performance of gated‐spectroscopy and imaging on isolated beating rat hearts at L‐band. A synchronized pulsing and timing system capable of gated acquisitions of up to 256 images per cycle, with rates of up to 16 Hz was developed. The temporal and spatial accuracy of this instrumentation was verified using a specially designed beating heart‐shaped isovolumic phantom with electromechanically driven sinusoidal motion at a cycle rate of 5 Hz. Gated EPR imaging was performed on a series of isolated rat hearts perfused with nitroxide spin labels. These hearts were paced at a rate of 6 Hz with either 16 or 32 gated images acquired per cardiac contractile cycle. The images enabled visualization of the time‐dependent alterations in the free radical distribution and anatomical structure of the heart that occur during the cardiac cycle.
Evaluation of intracellular diffusion in normal and globally‐ischemic rat brain via 133Cs NMR
Authors: Neil Jeffrey J. , Duong Timothy Q. , Ackerman Joseph J. H. 
Published: February 2011

AbstractThe question of whether the apparent diffusion coefficient (ADC) of intracellular water changes after brain injury was addressed by using 133Cs as an indicator to report on the state of the intracellular environment. Cesium is an NMR‐detect‐able potassium analog that accumulates in the intracellular space and is detectable in rat brain after being added to the animal's diet. The ADC of cesium was measured before and after the death of the rat. The cesium ADC fell from 0.91 ± 0.05 × 10−3 mm2/s (mean ± SEM, n = 5) in the alive rat to 0.71 ± 0.05 × 10−3 mm2/s within 20 min (the best time resolution of the experiment) of the death of the animal and stayed at this value for at least 3 h (P < 0.001). Assuming that the ADC of cesium reflects motion in the intracellular environment, these results support the idea that there are changes associated with cell injury that would cause a reduction in the ADC of intracellular water. Hence, one factor contributing to the decrease in water ADC after brain injury is a change in the ADC of intracellular water.
Evaluation of triple‐quantum‐filtered 23Na NMR in monitoring of intracellular na content in the perfused rat heart: Comparison of intra‐ and extracellular transverse relaxation and spectral amplitudes
Authors: Dizon José M. , Tauskela Joseph S. , Wise David , Burkhoff Daniel , Cannon Paul J. , Katz José 
Published: February 2011

AbstractMultiple‐quantum filtered (MQF) NMR offers the possibility of monitoring intracellular (IC) Na content in the absence of shift reagents (SR), provided that (i) the contribution from IC Na to the MQF spectrum is substantial and responds to a change in IC Na content, and (ii) the amplitude of the extracellular (EC) MQF component remains constant during a change in IC Na content. The validity and basis for these conditions were examined in isolated perfused rat hearts using SR‐aided and SR‐free triple‐quantum filtered (TQF) 23NaNMR. Despite a myocardial Na content that was only ˜1/70 that of EC Na. IC Na contributed to over 25% of the total TQF spectrum acquired in the absence of SR. Transverse relaxation times (T2) were approximately twice as long for EC compared to IC Na, despite SR‐induced relaxation of T2 for the former pool. However, the efficiency of generation of the TQF signal was similar for IC and EC Na, indicating that a much greater percentage of IC relative to EC Na exhibits TQ coherence. During constant perfusion with ouabain (0.2 mM for 25 min) or with a hypoxic and aglycemic solution (50 min), the amplitude of the IC TQF spectrum increased by ˜330% and ˜280%, respectively. In contrast, the amplitude of the EC TQF spectra remained essentially constant for both interventions. The amplitude for IC Na increased ˜250% relative to baseline during no‐flow ischemia (60 min), whereas the amplitude of the EC TQF spectra decreased by ˜33% before stabilizing. In SR‐free experiments, the TQF spectral amplitude increased ˜2‐fold during the constant perfusion interventions, but did not change significantly during no‐flow ischemia. These data suggest that the change in the TQF spectral amplitude during constant perfusion interventions is from IC Na, and that TQF techniques in the absence of SR may be useful in monitoring IC Na during these interventions. The fall in the amplitude of the EC TQF spectral amplitude during no‐flow ischemia complicates the use of TQF techniques without SR during this intervention.
Noninvasive temperature measurement in Vivo using a temperature‐sensitive lanthanide complex and 1H magnetic resonance spectroscopy
Authors: Frenzel Thomas , Roth Klaus , Koßler Susanne , Radüchel Bernd , Bauer Hans , Platzek Johannes , Weinmann Hanns‐Joachim 
Published: February 2011

AbstractA new lanthanide complex, praseodymium‐2‐methoxyethyl‐DO3A, was tested as a temperature indicator for 1H magnetic resonance spectroscopy under in vivo conditions, using a 2‐T imaging system. The chemical shift of the methoxy group of the compound is strongly temperature dependent. In vitro, a shift change of −0.131 ppm/°C was found. The signal was shifted by about −24 ppm relative to the water signal, allowing easy water suppression and signal identification in vivo. The body temperatures of eight anesthetized rats were measured in the liver after intravenous administration of 1 mmol/kg of the praseodymium complex under different heating conditions of the animal. The temperatures calculated from the spectra were in good agreement (deviation < ± 1°C) with values obtained simultaneously with a thermocouple placed in the rectum of the animals.
Phase‐Encode reordering to minimize errors caused by motion
Authors: MacGowan Christopher K. , Wood Michael L. 
Published: February 2011

AbstractA new method for suppressing the effects of motion in MR images by reordering the acquisition of k space has been developed. Existing reordering methods suffer from image blurring. The method presented here applies specifically to translation along the phase‐encoding direction, in which case it reduces both ghosting and blurring. The method is conceptually similar to a linear phase shift of k space, except that it has the advantage of not corrupting stationary structures inadvertently. The method is intended for anatomic sites in which substantial translational motion occurs along the phase‐encoding direction, such as the cranial‐caudal motion of the liver and kidneys. The reordering method is motivated from an analysis of factors affecting the severity of motion artifacts. The theory behind the reordering method is described and validated experimentally by imaging a moving phantom.
Transesophageal cardiac pacing during magnetic resonance imaging: Feasibility and safety considerations
Authors: Hofman Mark B. M. , de Cock Carel C. , van der Linden Johannes C. , van Rossum Albert C. , Visser Frans C. , Sprenger M. , Westerhof N. 
Published: February 2011

AbstractThe feasibility and safety of transesophageal cardiac pacing during clinical MRI at 1.5 Tesla is considered. An MRI compatible pace catheter was developed. In vitro testing showed a normal performance of the pulse generator, image artifacts that extended less than 11 mm from the catheter, and a less than 5% increase in noise. Cardiac stimulation induced by MRI was not observed and, theoretically, is not expected. Potentially, tissue around the catheter tip may become heated. This heating (ΔT) was monitored. Eight dogs were exposed to MRI during pacing. For low RF radiation exposure, a time‐averaged squared B1 field below 0.08 pT2 (SAR < 0.03 W/kg), ΔT was below 1°C. For high RF radiation exposure, but at normal RF radiation specific absorption rate (0.4 W/kg), ΔT was 5°C. Thus, transesophageal atrial pacing during MRI at low RF exposure seems to be possible to perform cardiac stress studies or to correct unstable heart rates.
A method for generating magnetic resonance microimaging T2 maps with low sensitivity to diffusion
Authors: Mlynárik Vladimír , Degrassi Anna , Toffanin Renato , Jarh Orest , Vittur Franco 
Published: February 2011

AbstractGenerating T2 maps in magnetic resonance microimaging is often complicated by the self‐diffusion of water molecules. A modification of the standard spin‐echo pulse sequence is proposed which minimizes this effect. Experiments with doped water confirmed that the T2 values obtained with the modified sequence were equal within the experimental error to the value obtained by the spectroscopic Carr‐Purcell‐Meiboom‐Gill method. The applicability of the technique is demonstrated by generating T2 maps of porcine articular cartilage. Key words: MR microimaging; relaxation; diffusion; cartilage.