bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical diffusion for flow‐aligned unstructured grids with application to estuarine modeling
Authors: Holleman Rusty , Fringer Oliver , Stacey Mark
Published: February 2013

The benefits of unstructured grids in hydrodynamic models are well understood but in many cases lead to greater numerical diffusion compared with methods available on structured grids. The flexible nature of unstructured grids, however, allows for the orientation of the grid to align locally with the dominant flow direction and thus decrease numerical diffusion. We investigate the relationship between grid alignment and diffusive errors in the context of scalar transport in a triangular, unstructured, 3‐D hydrodynamic code. Analytical results are presented for the 2‐D anisotropic numerical diffusion tensor and verified against idealized simulations. Results from two physically realistic estuarine simulations, differing only in grid alignment, show significant changes in gradients of salinity. Changes in scalar gradients are reflective of reduced numerical diffusion interacting with the complex 3‐D structure of the transporting flow. We also describe a method for utilizing flow fields from an unaligned grid to generate a flow‐aligned grid with minimal supervision. Copyright © 2013 John Wiley & Sons, Ltd.
Detecting unfrozen sediments below thermokarst lakes with surface nuclear magnetic resonance
Authors: Parsekian Andrew D. , Grosse Guido , Walbrecker Jan O. , Müller‐Petke Mike , Keating Kristina , Liu Lin , Jones Benjamin M. , Knight Rosemary
Published: February 2013

A talik is a layer or body of unfrozen ground that occurs in permafrost due to an anomaly in thermal, hydrological, or hydrochemical conditions. Information about talik geometry is important for understanding regional surface water and groundwater interactions as well as sublacustrine methane production in thermokarst lakes. Due to the direct measurement of unfrozen water content, surface nuclear magnetic resonance (NMR) is a promising geophysical method for noninvasively estimating talik dimensions. We made surface NMR measurements on thermokarst lakes and terrestrial permafrost near Fairbanks, Alaska, and confirmed our results using limited direct measurements. At an 8 m deep lake, we observed thaw bulb at least 22 m below the surface; at a 1.4 m deep lake, we detected a talik extending between 5 and 6 m below the surface. Our study demonstrates the value that surface NMR may have in the cryosphere for studies of thermokarst lake hydrology and their related role in the carbon cycle.
Intra‐plate seismicity and flexural stresses in central Brazil
Authors: Assumpção Marcelo , Sacek Victor
Published: February 2013

Explaining intra‐plate seismicity is a challenging task. Different models have been proposed combining weak zones and stress concentration mechanisms. Here we propose that flexural deformation is a major factor to explain seismicity in Central Brazil. A SW‐NE‐oriented seismic zone between the Amazon and the São Francisco cratons coincides with high gravity anomalies, possibly due to a SW‐NE belt of thin crust. The load from the high‐density, shallow mantle rocks causes upper crustal compressional stresses up to 100 MPa in the 200 km wide seismic zone. Away from the central zone of horizontal compression, extensional stresses in the peripheral bulge balance the regional compression explaining the aseismic areas. Three other seismic clusters in Brazil also correlate with high gravity anomalies, suggesting that flexural deformation contributes significantly to explain mid‐plate seismicity in Brazil.
MicroRNA-140-5p suppresses tumor growth and metastasis by targeting transforming growth factor β receptor 1 and fibroblast growth factor 9 in hepatocellular carcinoma
Authors: Yang Hao , Fang Feng , Chang Ruimin , Yang Lianyue
Published: February 2013

By comparing the expression profiles of microRNAs (miRNAs) in different hepatocellular carcinoma (HCC) subtypes, we identified miR-140-5p as an HCC-related miRNA. We found that miR-140-5p was significantly decreased in HCC tissues and all of six liver cancer cell lines examined and its expression levels were correlated with multiple nodules, vein invasion, capsular formation, and differentiation, as well as overall and disease-free survival of HCC. We also found that miR-140-5p suppressed HCC cell proliferation and HCC metastasis. Multipathway reporter arrays suggested that miR-140-5p inhibited transforming growth factor β (TGF-β) and mitogen-activated protein kinase / extracellular signal-regulated kinase (MAPK/ERK) signaling. TGFB receptor 1 (TGFBR1) and fibroblast growth factor 9 (FGF9) were then characterized as the direct targets for miR-140-5p after it was found that ectopic miR-140-5p expression suppressed TGFBR1 and FGF9 expression. Silencing TGFBR1 and FGF9 by small interfering RNA (siRNA) resembled the phenotype resulting from ectopic miR-140-5p expression, while overexpression of TGFBR1 and FGF9 attenuated the effect of miR-140-5p on HCC growth and metastasis. Conclusion: These data elucidated a tumor suppressor role for miR-140-5p in HCC development and progression with therapeutic potential. Our correlation studies in clinical HCC samples further suggest that miR-140-5p could be a valuable biomarker for HCC prognosis. (Hepatology 2013 )
Intestinal microbiota in patients with nonalcoholic fatty liver disease
Authors: Mouzaki Marialena , Comelli Elena M. , Arendt Bianca M. , Bonengel Julia , Fung Scott K. , Fischer Sandra E. , McGilvray Ian D. , Allard Johane P.
Published: February 2013

Despite evidence that the intestinal microbiota (IM) is involved in the pathogenesis of obesity, the IM composition of patients with nonalcoholic fatty liver disease (NAFLD) has not been well characterized. This prospective, cross-sectional study was aimed at identifying differences in IM between adults with biopsy-proven NAFLD (simple steatosis [SS] or nonalcoholic steatohepatitis [NASH]) and living liver donors as healthy controls (HC). Fifty subjects were included: 11 SS, 22 NASH, and 17 HC. One stool sample was collected from each participant. Quantitative real-time polymerase chain reaction was used to measure total bacterial counts, Bacteroides/Prevotella (herein referred to as Bacteroidetes), Clostridium leptum, C. coccoides, bifidobacteria, Escherichia coli and Archaea in stool. Clinical and laboratory data, food records, and activity logs were collected. Patients with NASH had a lower percentage of Bacteroidetes (Bacteroidetes to total bacteria counts) compared to both SS and HC (P = 0.006) and higher fecal C. coccoides compared to those with SS (P = 0.04). There were no differences in the remaining microorganisms. As body mass index (BMI) and dietary fat intake differed between the groups (P < 0.05), we performed linear regression adjusting for these variables. The difference in C. coccoides was no longer significant after adjusting for BMI and fat intake. However, there continued to be a significant association between the presence of NASH and lower percentage Bacteroidetes even after adjusting for these variables (P = 0.002; 95% confidence interval = −0.06 to −0.02).

Conclusion:

There is an inverse and diet-/BMI-independent association between the presence of NASH and percentage Bacteroidetes in the stool, suggesting that the IM may play a role in the development of NAFLD. (HEPATOLOGY 2013 )
The effect of zinc and the role of p53 in copper‐induced cellular stress responses
Authors: Formigari Alessia , Gregianin Elisa , Irato Paola
Published: February 2013

Metals can directly or indirectly cause an increase in reactive oxygen species (ROS) accumulation in cells, and this may result in programmed cell death. A number of previous studies have shown that zinc (Zn) modulates mitogenic activity via several signalling pathways, such as AKT, mitogen‐activated protein kinase (MAPK), nuclear factor‐kappa B (NF ‐κB), AP‐1 and p53. The exact role that Zn plays in the regulation of apoptosis remains ambiguous. Intracellular free Zn modulates p53 activity and stability, and excess Zn alters the p53 protein structure and down‐regulates p53's binding to DNA. Copper (Cu) accumulation causes apoptosis that seems to be mediated by DNA damage and subsequent p53 activation. Cu can also displace Zn from its normal binding site on p53, resulting in abnormal protein folding and disruption of p53 function. In spite of the induction of the tumour suppressor p53, hepatic Cu accumulation significantly increases the risk of cancerous neoplasm both in humans and rats, suggesting that p53 function may be impaired in these cells. It is generally understood that imbalances in Cu and Zn levels may lead to a higher prevalence of p53 mutations. An increased number of p53 mutations have been found in liver samples from Wilson's disease (WD) patients. High levels of the p53 mutation most probably contribute to the pathogenesis of cancer in individuals with WD, but the cause and effect are not clear. The protein p53 also plays a crucial role in the transcriptional regulation of metallothionein, which indicates a novel regulatory role for p53. This review discusses the central role of p53 and the redox‐inert metal Zn in the cellular stress responses induced by the redox active biometal Cu. Copyright © 2013 John Wiley & Sons, Ltd.
Neural responses to electrical stimulation on patterned silk films
Authors: Hronik‐Tupaj Marie , Raja Waseem Khan , Tang‐Schomer Min , Omenetto Fiorenzo G. , Kaplan David L.
Published: February 2013

Peripheral nerve injury is a critical issue for patients with trauma. Following injury, incomplete axon regeneration or misguided axon innervation into tissue will result in loss of sensory and motor functions. The objective of this study was to examine axon outgrowth and axon alignment in response to surface patterning and electrical stimulation. To accomplish our objective, metal electrodes with dimensions of 1.5 mm × 4 cm, were sputter coated onto micropatterned silk protein films, with surface grooves 3.5 μm wide × 500 nm deep. P19 neurons were seeded on the patterned electronic silk films and stimulated at 120 mV, 1 kHz, for 45 min each day for 7 days. Responses were compared with neurons on flat electronic silk films, patterned silk films without stimulation, and flat silk films without stimulation. Significant alignment was found on the patterned film groups compared with the flat film groups. Axon outgrowth was greater (p < 0.05) on electronic films on days 5 and 7 compared with the unstimulated groups. In conclusion, electrical stimulation, at 120 mV, 1 kHz, for 45 min daily, in addition to surface patterning, of 3.5 μm wide × 500 nm deep grooves, offered control of nerve axon outgrowth and alignment. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2559–2572, 2013.
Calcium‐incorporated titanium surfaces influence the osteogenic differentiation of human mesenchymal stem cells
Authors: Sawada Rumi , Kono Ken , Isama Kazuo , Haishima Yuji , Matsuoka Atsuko
Published: February 2013

In this study, a titanium surface was chemically modified with calcium ions and assessed for its influence on osteogenic differentiation and molecular responses of human mesenchymal stem cells (hMSCs). Titanium disks were treated with NaOH (NaOH treatment), NaOH + CaCl2 (CaCl2 treatment), or NaOH + Ca(OH)2 (Ca(OH)2 treatment). Ca(OH)2 treatment caused significantly greater calcium incorporation onto the titanium surface and apatite formation than CaCl2 treatment. The morphology of hMSCs differed on CaCl2‐ and Ca(OH)2‐treated disks. The osteopontin (OPN) expression in hMSCs cultured on CaCl2‐treated titanium was significantly higher than that in cells cultured on NaOH‐treated disks; OPN expression was significantly higher in cells cultured on Ca(OH)2‐treated disks than on un‐, NaOH‐, and CaCl2‐treated disks. Osteocalcin (OCN) protein expression in hMSCs cultured on Ca(OH)2‐treated disks was significantly higher than that on all the other disks. Comparative expression profiling by DNA microarray and pathway analyses revealed that calcium modification of the titanium surface induced integrin β3 after OPN upregulation and promoted Wnt/β‐catenin signaling in hMSCs. In addition, Ca(OH)2 treatment upregulated the expression of bone morphogenetic protein 2, cyclooxygenase 2, and parathyroid hormone‐like hormone in comparison to CaCl2 treatment. These observations suggest that calcium‐modified titanium surfaces affect osteogenic differentiation in hMSCs and that Ca(OH)2 treatment induced osteogenic differentiation in hMSCs, whereas CaCl2 treatment had a limited effect. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2573–2585, 2013. © 147.
Ultra‐Trace Silver Determination in Biological and Water Samples by Electrothermal Atomic Absorption Spectrometry after Electrodeposition on a Graphite Probe
Authors: Moradkhani Reza , Rouhollahi Ahmad , Shirkhanloo Hamid , Ghasemi Jahan B
Published: February 2013

A rapid and simple procedure was developed for selective and sensitive determination of ultra‐trace silver in biological and environmental samples using the electrodeposition on a graphite probe modified with palladium followed by electrothermal atomic absorption spectrometry. Several experimental parameters for the electrodeposition, such as deposition potential, electrolyte concentration, pH of solution and deposition time were optimized. The calibration graph after preconcentration was linear in the range of 10‐250 ngL−1 with correlation coefficient of 0.9989 under the optimum conditions for procedure. The limits of detection (LOD) and quantification (LOQ) base on (3σ) and (10σ) were 2.8 ngL−1 and 9.4 ngL−1 respectively. Related standard deviation (RSD) for eight replicate measurements of 100 ngL−1 silver was 4.3%. Samples were digested completely in a closed microwave digestion system using only perchloric acid, and interference owing to various cations was also investigated. The proposed procedure was successfully applied to determine silver in blood, urine and some environmental samples with satisfactory analytical results.
Vitrifolin A: A Norlabdane Diterpenoid from the Fruits of Vitex trifolia Linn. var. simplicifolia Cham
Authors: Zhang Teng , Zhang Chong Xi , Xie Wei Dong , Row Kyung Ho
Published: February 2013

A new norlabdane diterpenoid, named vitrifolin A, was isolated from the fruits of Vitex trifolia Linn. var. simplicifolia Cham. Its structure was elucidated by mean of spectroscopic methods, including HRESIMS, IR, 1D and 2D NMR. The inhibitory effect of vitrifolin A on nitric oxide production in lipopolysaccarideactivated mouse macrophages was also evaluated.
Dissolution behaviour of platinum by electro‐generated chlorine in hydrochloric acid solution
Authors: Kim Min‐seuk , Lee Jae‐chun , Park Sang‐woon , Jeong Jinki , Kumar Vinay
Published: February 2013

Background

Depletion of primary resources, stringent environmental regulations, and the requirement for energy efficient and eco‐friendly processes have created research interest in recovering Pt from secondary resources using electro‐generated chlorine in HCl solution.

Results

Platinum dissolution rate was found to increase by a factor of 2.5 by increasing the HCl concentration from 3.0 to 5.0 mol L‐1 at 70°C, while maintaining total chloride ions at 5.0 mol L‐1 with NaCl. Increasing the aqueous chlorine concentration made no improvement to the dissolution rate. A theoretical calculation of distribution for chlorine species showed a predominance of Cl3− ions in comparison with Cl2(aq) upon increasing the acid concentration to above 5.0 mol L‐1; raising temperature also increased the dissolution rate. The activation energies of Pt dissolution in the 5.0 mol L‐1 HCl solution were 82.3 and 83.5 kJ mol‐1 at 5.0 and 15 mmol L‐1 aqueous chlorine concentration, respectively.

Conclusions

Eco‐friendly electro‐generated chlorine leaching was applied for the dissolution of Pt in hydrochloric acid solutions. Increasing HCl concentration and solution temperature effectively enhanced Pt dissolution during leaching. A quantitative investigation of Pt dissolution rate verified the chemical reaction control of Pt dissolution rather than mass transfer.
Highly efficient and simultaneous removal of 2‐mercaptobenzothiazole and 2‐mercaptobenzoxazole from water samples by copper oxide nanoparticles
Authors: Parham Hooshang , Khoshnam Farzaneh
Published: February 2013

BACKGROUND

This study introduces a method for simultaneous removal of 2‐mercaptobenzoxazole (2MBO) and 2‐mercaptobenzothiazole (2MBT) from water samples. The method uses a cartridge loaded with copper oxide nanoparticles as an efficient adsorbent to separate these hazardous mercaptans from aqueous solutions in a flow process.

RESULTS

The effects of some important parameters such as amounts of adsorbent, pH, buffer type and its volume, electrolyte concentration, contact time, flow rate, tolerable volume of solution, reusability of cartridges and interfering ions on removal efficiency were studied. Data on adsorption were analyzed using linear and non‐linear forms of first‐ and second‐order kinetic equations and also Langmuir and Freundlich isotherm models and results showed that maximum adsorption amounts of 90.9 mg g−1 and 158.7 mg g−1, were obtained for 2MBO and 2MBT, respectively.

CONCLUSION

The proposed removal method is independent of pH level of the sample solution and is effective over a wide range of pH values. Using a copper oxide nanoparticle loaded cartridge (CONLC) has the advantage that there is no need to collect nanoparticles after the removal process and that CONLC can be reused for further removal processes (at least three times). This method was successfully applied to remove 2MBT (≥95% removal) from the cooling water of a 3000 MW power plant. © 2013 Society of Chemical Industry
A review: production of activated carbon from agricultural byproducts via conventional and microwave heating
Authors: Alslaibi Tamer M. , Abustan Ismail , Ahmad Mohd Azmier , Foul Ahmad Abu
Published: February 2013

Production of activated carbon (AC) from agricultural byproducts is a research field that has gained increased interest in recent years because of its potential for the disposal of agro‐residues. At the same time, a beneficial byproduct that can be used in a number of environmental applications is produced. This paper surveys the developments in the production processes of AC from agricultural byproducts in the past 7 years from 2005 to 2012 via conventional and microwave heating. Emphasis is placed on the applied methodology and the influences of activating conditions, such as carbonization temperature, retention time, and impregnation ratio. From the review of AC production processes, agricultural wastes produced by a chemical method with microwave heating can be a source of AC with relatively higher surface area than that produced via conventional heating. © 2013 Society of Chemical Industry
A comparison of N‐doped TiO2 photocatalysts preparation methods and studies on their catalytic activity
Authors: Liu Yanan , He Jun , Sun Yu , Hu Jinlong , Li Chunyan , Xue Gang , Ognier Stéphanie
Published: February 2013

Background

N‐doped TiO2 can narrow the TiO2 forbidden band and thereby increase its catalytic activity under visible light. In this work, three methods (the sol–gel method (SG), the tetrabutyl titanate hydrolysis precipitation method TN', and the H2O2‐modified method (TNH)) were used to prepare N‐doped TiO2 photocatalysts. The Reactive Red‐Violet dye (KN‐R) was used as the target pollutant. The catalytic activities of the photocatalysts prepared via the three methods were compared and studied.

Results

The structures and optoelectronic properties of these catalysts were characterized by various means. The results demonstrated that the N‐doped TiO2 catalyst synthesized using the TNH method exhibited the most efficient catalytic activity under visible light and produced a degradation rate of 90% for the Reactive Red‐Violet dye. The N‐doped TiO2 prepared using the SG method exhibited the lowest catalytic activity under both UV and visible light. The kinetics of photocatalysis degradation for KN‐R by N‐doped TiO2 prepared by TNH method was studied and found to be zero order due to the good adsorption effect between KN‐R and TiO2.

Conclusion

The N‐doped TiO2 prepared by TNH method showed good photocatalytic activity in the case of degrading dye under both UV and visible light. © 2013 Society of Chemical Industry
An Efficient Synthesis of New Dispiropyrrolidine Derivatives via Three‐Component 1,3‐Dipolar Cycloaddition Reaction
Authors: Hu Yu , Shi Da‐Qing
Published: February 2013

A series of new dispiropyrrolidine derivatives were synthesized via the three‐component 1,3‐dipolar cycloaddition reaction of azomethine ylides generated in situ by the decarboxylative condensation of acenaphthenequinone and sarcosine or l‐thioproline with 5‐benzylidene‐1,3‐dimethylpyrimidine‐2,4,6‐trione. The structures of the products were identified by IR, 1H‐NMR, and HRMS spectra.
Fabrication of Chitosan Nanoparticles with Aggregation‐Induced Emission Characteristics and Their Applications in Long‐Term Live Cell Imaging
Authors: Li Min , Hong Yuning , Wang Zhengke , Chen Sijie , Gao Meng , Kwok Ryan T. K. , Qin Wei , Lam Jacky W. Y. , Zheng Qichang , Tang Ben Zhong
Published: February 2013

Chitosan with tetraphenylethene pendants (TPE‐CS) are synthesized by reaction between amine and isothiocyanate groups of chitosan and tetraphenylethene (TPE), respectively. Nanoparticles of TPE‐CS (TPE‐CS NPs) are fabricated by ionic gelation method. The NPs are uniform in size, spherical in shape, monodispersed, and positive in surface charge. The suspension of TPE‐CS NPs emits strong blue fluorescence under photoexcitation due to the aggregation‐induced emission characteristics of the TPE moieties. The NPs can be internalized into cytoplasm through endocytosis pathway and retain inside the live cells to image the cells. Cytotoxicity assay reveals that TPE‐CS NPs are cytocompatible and thus can be used for long‐term live cell imaging.

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Movement Disorders in Adult Patients With Classical Galactosemia
Authors: Rubio‐Agusti Ignacio , Carecchio Miryam , Bhatia Kailash P. , Kojovic Maja , Parees Isabel , Chandrashekar Hoskote S. , Footitt Emma J. , Burke Derek , Edwards Mark J. , Lachmann Robin H.L. , Murphy Elaine
Published: February 2013

Classical galactosemia is an autosomal recessive inborn error of metabolism leading to toxic accumulation of galactose and derived metabolites. It presents with acute systemic complications in the newborn. Galactose restriction resolves these symptoms, but long‐term complications, such as premature ovarian failure and neurological problems including motor dysfunction, may occur despite adequate treatment. The objective of the current study was to determine the frequency and phenotype of motor problems in adult patients with classical galactosemia. In this cross‐sectional study, adult patients with a biochemically confirmed diagnosis of galactosemia attending our clinic were assessed with an interview and neurological examination and their notes retrospectively reviewed. Patients were classified according to the presence/absence of motor dysfunction on examination. Patients with motor dysfunction were further categorized according to the presence/absence of reported motor symptoms. Forty‐seven patients were included. Thirty‐one patients showed evidence of motor dysfunction including: tremor (23 patients), dystonia (23 patients), cerebellar signs (6 patients), and pyramidal signs (4 patients). Tremor and dystonia were often combined (16 patients). Thirteen patients reported motor symptoms, with 8 describing progressive worsening. Symptomatic treatment was effective in 4 of 5 patients. Nonmotor neurological features (cognitive, psychiatric, and speech disorders) and premature ovarian failure were more frequent in patients with motor dysfunction. Motor dysfunction is a common complication of classical galactosemia, with tremor and dystonia the most frequent findings. Up to one third of patients report motor symptoms and may benefit from appropriate treatment. Progressive worsening is not uncommon and may suggest ongoing brain damage in a subset of patients. © 2013 Movement Disorder Society
A Strategy Combining Differential Low‐Throughput Screening and Virtual Screening (DLS‐VS) Accelerating the Discovery of new Modulators for the Orphan GPR34 Receptor
Authors: Diaz Constantino , Labit‐Le Bouteiller Christine , Yvon Stéphane , Cambon‐Kernëis Aimée , Roasio Annette , Jamme Marie‐Françoise , Aries Amélie , Feuillerat Claude , Perret Eric , Guette Fréderique , Dieu Pierre , Miloux Brigitte , Albène Danielle , Hasel Nathalie , Kaghad Mourad , Ferran Edgardo , Lupker Jan , Ferrara Pascual
Published: February 2013

The DLS‐VS strategy was developed as an integrated method for identifying chemical modulators for orphan GPCRs. It combines differential low‐throughput screening (DLS) and virtual screening (VS). The two cascaded techniques offer complementary advantages and allow the experimental testing of a minimal number of compounds. First, DLS identifies modulators specific for the considered receptor among a set of receptors, through the screening of a small library with diverse chemical compounds. Then, an active molecular model of the receptor is built by homology to a validated template, and it is progressively refined by rotamers modification for key side‐chains, by VS of the already screened library, and by iterative selection of the model generating the best enrichment. The refined active model is finally used for the VS of a large chemical library and the selection of a small set of compounds for experimental testing. Applied to the orphan receptor GPR34, the DLS‐VS strategy combined the experimental screening of 20 000 compounds and the virtual screening of 1 250 000 compounds. It identified one agonist and eight inverse agonists, showing a high chemical diversity. We describe the method. The strategy can be applied to other GPCRs.
Keeping PASE with WEFT: SHWEFT–PASE pulse sequences for 1H NMR spectra of highly paramagnetic molecules
Authors: Helms Gregory , Satterlee James D.
Published: February 2013

Metalloproteins are a category of biomolecules in which the metal site is usually the locus of activity or function. In many cases, the metal ions are paramagnetic or have accessible paramagnetic states, many of which can be studied using NMR spectroscopy. Extracting useful information from 1H NMR spectra of highly paramagnetic proteins can be difficult because the paramagnetism leads to large resonance shifts (~400 ppm), extremely broad lines, extreme baseline nonlinearity, and peak shape distortion. It is demonstrated that employing polychromatic and adiabatic shaped pulses in simple pulse sequences, then combining existing sequences, leads to significant spectral improvement for highly paramagnetic proteins. These sequences employ existing technology, with available hardware, and are of short duration to accommodate short nuclear T1 and T2. They are shown to display uniform excitation over large spectral widths (~75 kHz), accommodate high repetition rates, produce flat baselines over 75 kHz while maintaining peak shape fidelity, and can be used to reduce spectral dynamic range. High‐spin (S = 5/2) metmyoglobin, a prototypical highly paramagnetic protein, was used as the test molecule. The resulting one‐dimensional (1D) pulse sequences combine shaped pulses with super‐water elimination Fourier transform, which can be further combined with paramagnetic spectroscopy to give shaped pulses with super‐water elimination Fourier transform–paramagnetic spectroscopy. These sequences require, at most, direct current offset correction and minimal phasing. The performance of these sequences in simple 1H 1D, 1D NOE, and two‐dimensional NOESY experiments is demonstrated for metmyoglobin and Paracoccus denitrificans Co2+‐amicyanin (S = 3/2), and employed to make new heme hyperfine resonance assignments for high‐spin metBjFixLH151–256, the heme sensing domain of Bradyrhizobium japonicum FixL. Copyright © 2013 John Wiley & Sons, Ltd.
Blind retrospective motion correction of MR images
Authors: Loktyushin Alexander , Nickisch Hannes , Pohmann Rolf , Schölkopf Bernhard
Published: February 2013

Purpose

Subject motion can severely degrade MR images. A retrospective motion correction algorithm, Gradient‐based motion correction, which significantly reduces ghosting and blurring artifacts due to subject motion was proposed. The technique uses the raw data of standard imaging sequences; no sequence modifications or additional equipment such as tracking devices are required. Rigid motion is assumed.

Methods

The approach iteratively searches for the motion trajectory yielding the sharpest image as measured by the entropy of spatial gradients. The vast space of motion parameters is efficiently explored by gradient‐based optimization with a convergence guarantee.

Results

The method has been evaluated on both synthetic and real data in two and three dimentions using standard imaging techniques. MR images are consistently improved over different kinds of motion trajectories. Using a graphics processing unit implementation, computation times are in the order of a few minutes for a full three‐dimentional volume.

Conclusion

The presented technique can be an alternative or a complement to prospective motion correction methods and is able to improve images with strong motion artifacts from standard imaging sequences without requiring additional data. Magn Reson Med 70:1608–1618, 2013. © 2013 Wiley Periodicals, Inc.
Electrical Properties Tomography in the Human Brain at 1.5, 3, and 7T: A Comparison Study
Authors: van Lier Astrid L. H. M. W. , Raaijmakers Alexander , Voigt Tobias , Lagendijk Jan J. W. , Luijten Peter R. , Katscher Ulrich , van den Berg Cornelis A. T.
Published: February 2013

Purpose

To investigate the effect of magnetic field strength on the validity of two assumptions (namely, the “transceive phase assumption” and the “phase‐only reconstruction”) for electrical properties tomography (EPT) at 1.5, 3, and 7T.

Theory

Electrical properties tomography is a method to map the conductivity and permittivity using MRI; the B1+ amplitude and phase is required as input. The B1+ phase, however, cannot be measured and is therefore deduced from the measurable transceive phase using the transceive phase assumption. Also, earlier studies showed that the B1+ amplitude is not always required for a reliable conductivity reconstruction; this is the so‐called “phase‐only conductivity reconstruction.”

Methods

Electromagnetic simulations and MRI measurements of phantoms and the human head.

Results

Reconstructed conductivity and permittivity maps based on B1+ distributions at 1.5, 3, and 7T were compared to the expected dielectric properties. The noise level of measurements was also determined.

Conclusion

The transceive phase assumption is most accurate for low‐field strengths and low permittivity and in symmetric objects. The phase‐only conductivity reconstruction is only applicable at 1.5 and 3T for the investigated geometries. The measurement precision was found to benefit from a higher field strength, which is related to increased signal‐to‐noise ratio (SNR) and increased curvature of the B1+ field. Magn Reson Med 71:354–363, 2014. © 2013 Wiley Periodicals, Inc.
4D Dark Blood Arterial Wall Magnetic Resonance Imaging: Methodology and Demonstration in the Carotid Arteries
Authors: Koktzoglou Ioannis
Published: February 2013

Purpose

To propose and test a four‐dimensional (4D) dark‐blood magnetic resonance imaging (MRI) method based on a radial sampling trajectory capable of displaying the human arterial wall and its motion in three spatial dimensions over the cardiac cycle.

Methods

The carotid arteries of volunteer and patient subjects were imaged with the proposed 4D dark‐blood MRI sequence on a 3T scanner. Validation of arterial lumen and arterial wall areas obtained with the proposed 4D dark‐blood technique was made with respect to established two‐dimensional bright‐blood cine and high spatial resolution three‐dimensional dark‐blood MRI protocols, respectively.

Results

The proposed 4D MRI method provided for dark‐blood display of the carotid arterial wall and demonstrated its movement and distension over the cardiac cycle. Quantitative measurements of arterial lumen and wall areas were in statistical agreement with established MRI techniques.

Conclusion

4D blood suppressed MRI of the human vascular system with submillimeter isotropic spatial resolution is feasible in a clinically reasonable scan time, and data obtained in the carotid arteries show good agreement with established MRI techniques. Future efforts will examine the constellation of data provided by the method and investigate its utility for assessing cardiovascular risk. Magn Reson Med 69:956–965, 2013. © 2013 Wiley Periodicals, Inc.
Whole‐Heart Coronary MRA with 3D Affine Motion Correction Using 3D Image‐Based Navigation
Authors: Henningsson Markus , Prieto Claudia , Chiribiri Amedeo , Vaillant Ghislain , Razavi Reza , Botnar René M
Published: February 2013

Purpose

Robust motion correction is necessary to minimize respiratory motion artefacts in coronary MR angiography (CMRA). The state‐of‐the‐art method uses a 1D feet‐head translational motion correction approach, and data acquisition is limited to a small window in the respiratory cycle, which prolongs the scan by a factor of 2–3. The purpose of this work was to implement 3D affine motion correction for Cartesian whole‐heart CMRA using a 3D navigator (3D‐NAV) to allow for data acquisition throughout the whole respiratory cycle.

Methods

3D affine transformations for different respiratory states (bins) were estimated by using 3D‐NAV image acquisitions which were acquired during the startup profiles of a steady‐state free precession sequence. The calculated 3D affine transformations were applied to the corresponding high‐resolution Cartesian image acquisition which had been similarly binned, to correct for respiratory motion between bins.

Results

Quantitative and qualitative comparisons showed no statistical difference between images acquired with the proposed method and the reference method using a diaphragmatic navigator with a narrow gating window.

Conclusion

We demonstrate that 3D‐NAV and 3D affine correction can be used to acquire Cartesian whole‐heart 3D coronary artery images with 100% scan efficiency with similar image quality as with the state‐of‐the‐art gated and corrected method with approximately 50% scan efficiency. Magn Reson Med 71:173–181, 2014. © 2013 Wiley Periodicals, Inc.
A fracture mapping and extended finite element scheme for coupled deformation and fluid flow in fractured porous media
Authors: Lamb Anthony R. , Gorman Gerard J. , Elsworth Derek
Published: February 2013

This paper presents a fracture mapping (FM) approach combined with the extended finite element method (XFEM) to simulate coupled deformation and fluid flow in fractured porous media. Specifically, the method accurately represents the impact of discrete fractures on flow and deformation, although the individual fractures are not part of the finite element mesh. A key feature of FM‐XFEM is its ability to model discontinuities in the domain independently of the computational mesh. The proposed FM approach is a continuum‐based approach that is used to model the flow interaction between the porous matrix and existing fractures via a transfer function. Fracture geometry is defined using the level set method. Therefore, in contrast to the discrete fracture flow model, the fracture representation is not meshed along with the computational domain. Consequently, the method is able to determine the influence of fractures on fluid flow within a fractured domain without the complexity of meshing the fractures within the domain. The XFEM component of the scheme addresses the discontinuous displacement field within elements that are intersected by existing fractures. In XFEM, enrichment functions are added to the standard finite element approximation to adequately resolve discontinuous fields within the simulation domain. Numerical tests illustrate the ability of the method to adequately describe the displacement and fluid pressure fields within a fractured domain at significantly less computational expense than explicitly resolving the fracture within the finite element mesh. Copyright © 2013 John Wiley & Sons, Ltd.
Personality Types and Development of Adolescents’ Conflict with Friends
Authors: Yu Rongqin , Branje Susan J. T. , Keijsers Loes , Meeus Wim H. J.
Published: February 2013

This study examined the development of adolescents’ conflict frequency and conflict resolution with their best friends, and tested whether adolescents with different personality types differed in these developmental changes from early to middle adolescence. Dutch adolescents (N = 922, 468 boys; Mage = 12.4 years at first wave) annually filled in questionnaires for five consecutive years. Growth modelling revealed that, whereas adolescents’ conflict frequency and hostile conflict resolution did not change, positive problem solving, withdrawal, and compliance during conflict with best friends increased from age 12 to 16 years. Adolescents with different personality types differed in the mean levels of conflict frequency and conflict resolution strategies. That is, resilients had less conflict with friends than undercontrollers and overcontrollers. During conflict, resilients used the least hostile conflict resolution and compliance, and employed the most positive problem solving. Undercontrollers adopted the least positive problem solving, and overcontrollers complied and withdrew the most. Using a person–centred approach, three developmental conflict resolution types were identified based on different constellations of the four conflict resolution strategies over time. Adolescents with different personality types had different distributions on the conflict resolution types. Copyright © 2013 John Wiley & Sons, Ltd.
Comparative Pharmacokinetics, Pharmacodynamics, and Tolerability of Ertapenem 1 Gram/Day Administered as a Rapid 5‐Minute Infusion versus the Standard 30‐Minute Infusion in Healthy Adult Volunteers
Authors: Wiskirchen Dora E. , Housman Seth T. , Quintiliani Richard , Nicolau David P. , Kuti Joseph L.
Published: February 2013

Study Objective

To compare ertapenem pharmacokinetics, pharmacodynamics, and tolerability when administered as a rapid 5‐minute infusion to the standard 30‐minute infusion.

Design

Prospective, randomized, crossover pharmacokinetic study.

Setting

Clinical research center.

Subjects

Twelve healthy adult volunteers.

Intervention

Each subject received ertapenem 1 g intravenously, administered either as a rapid 5‐minute infusion or the standard 30‐minute infusion, every 24 hours for 3 days (first phase); after a 4‐day washout period, each subject then received the other infusion every 24 hours for 3 days (second phase).

Measurements and Main Results

Plasma samples were collected after the first and third (steady‐state) doses of each study phase, and protein binding was assessed by use of ultrafiltration. Pharmacokinetic analyses were conducted using noncompartmental and compartmental methods. A 5000‐subject Monte Carlo simulation was used to assess the probability of target attainment for free drug concentration remaining above the minimum inhibitory concentration (MIC) for 40% or greater of the dosing interval (40% fT > MIC) over an MIC range. Ertapenem was well tolerated and adverse events were similar for both infusions. The ertapenem steady‐state mean ± SD maximum concentrations were 193.3 ± 43.3 and 165.7 ± 20.4 mg/L for the 5‐ and 30‐minute infusions, respectively; the mean ± SD areas under the concentration‐time curves from 0–24 hours were 561.2 ± 77.0 and 531.3 ± 56.9 μg · hr/ml (geometric mean ratio 1.008, 90% confidence interval 0.999–1.017), respectively. Protein binding was concentration dependent (range 87.9–98.9%). A two‐compartment model best described ertapenem pharmacokinetics with the following parameter estimates: clearance 1.89 ± 0.19 L/hr, volume of central compartment 5.04 ± 0.56 L, and transfer constants k12 0.43 ± 0.08/hr and k21 0.44 ± 0.07/hr. The probabilities of target attainment for 5‐ and 30‐minute infusions were 97.0% and 97.9% at an MIC of 0.25 mg/L and 1.7% and 2.8% at an MIC of 0.5 mg/L, respectively.

Conclusion

Ertapenem administered as a rapid 5‐minute infusion provides a well tolerated, bioequivalent, and pharmacodynamically equivalent regimen to the 30‐minute infusion at clinically relevant MICs.
Neurogenetic Disorders and Treatment of Associated Seizures
Authors: Faulkner Michele A. , Singh Sanjay P.
Published: February 2013

Seizures are a frequent complication associated with several neurogenetic disorders. Antiepileptic medications remain the mainstay of treatment in these patients. We summarized the available data associated with various antiepileptic therapies used to treat patients with neurogenetic disorders who experienced recurrent seizures. AMEDLINEsearch was conducted to identify articles and abstracts describing the use of antiepileptic therapy for the treatment of various neurogenetic syndromes. Of all the neurogenetic syndromes, only autism spectrum disorders, Angelman syndrome,Rett syndrome,Dravet syndrome, and tuberous sclerosis complex were identified as having sufficient published information to evaluate therapy. Some efficacy trends were identified, including frequent successes with valproic acid with clonazepam for epilepsy with Angelman syndrome; valproic acid, stiripentol, and clobazam (triple combination therapy) for epilepsy with Dravet syndrome; and vigabatrin for infantile spasms associated with tuberous sclerosis complex. Due to a paucity of information regarding the mechanisms by which seizures are generated in the various disorders, approach to seizure control is primarily based on clinical experience and a limited amount of study data exploring patient outcomes. Although exposure of the developing brain to antiepileptic medications is of some concern, the control of epileptic activity is an important undertaking in these individuals, as the severity of eventual developmental delay often appears to correlate with the severity of seizures. As such, early aggressive therapy is warranted.
The energy payback time of advanced crystalline silicon PV modules in 2020: a prospective study
Authors: Mann Sander A. , de Wild‐Scholten Mariska J. , Fthenakis Vasilis M. , van Sark Wilfried G.J.H.M. , Sinke Wim C.
Published: February 2013

The photovoltaic (PV) market is experiencing vigorous growth, whereas prices are dropping rapidly. This growth has in large part been possible through public support, deserved for its promise to produce electricity at a low cost to the environment. It is therefore important to monitor and minimize environmental impacts associated with PV technologies. In this work, we forecast the environmental performance of crystalline silicon technologies in 2020, the year in which electricity from PV is anticipated to be competitive with wholesale electricity costs all across Europe. Our forecasts are based on technological scenario development and a prospective life cycle assessment with a thorough uncertainty and sensitivity analysis. We estimate that the energy payback time at an in‐plane irradiation of 1700 kWh/(m2 year) of crystalline silicon modules can be reduced to below 0.5 years by 2020, which is less than half of the current energy payback time. Copyright © 2013 John Wiley & Sons, Ltd.
Genetic and environmental factors interplay in Parkinson's disease
Authors: Church Alistair
Published: February 2013

Our series of Commentaries from the Primary Care Neurology Society (P‐CNS) aim to provide a primary care perspective on the neurology articles featured in each issue of Progress. Here, Dr Alistair Church provides a commentary on our article ‘Pesticides and Parkinson's disease pathogenesis: the controversy continues’ (see page 20 of this issue).
Myasthenia gravis unmasked by antipsychotic medication
Authors: Wilson Carol Lee , Ferguson John
Published: February 2013

Several medications, including some antipsychotics, have been shown to worsen myasthenia gravis symptoms. Here, Drs Wilson and Ferguson report the case of a patient with bipolar affective disorder, whose undiagnosed myasthenia gravis was unmasked by antipsychotic medication used to treat a manic relapse and whose symptoms were first attributed to antipsychotic‐associated extrapyramidal sideeffects.
On AlO Emission Spectroscopy as a Diagnostic in Energetic Materials Testing
Authors: Peuker Jennifer Mott , Lynch Patrick , Krier Herman , Glumac Nick
Published: February 2013

The emission of AlO is commonly observed in tests involving aluminum combustion in propellants and explosives. Such emission has been used as a signature of combustion, as a tool for measuring ignition and reaction times, and as a thermometer. This paper provides a critical review of methodologies exploiting AlO emission spectroscopy as a quantitative tool in energetics testing. Controlled tests involving aluminized explosives, as well as those using added alumina, are conducted, in which AlO emission is quantified and compared to total oxidation in the final residue. Experimental parameters such as optical depth and fireball confinement are systematically varied to examine the effect on AlO emission. We find that thermometry using AlO remains valid, and a new approach to using low resolution spectra is proposed. However, AlO emission spectroscopy or photometry can be quantitatively correlated to ignition and burning time, or used to infer the presence or absence of aluminum combustion, only under a limited set of circumstances. Factors that limit the ability to use AlO emission quantitatively are discussed in depth.
Preparation and Properties of 2,6‐Diamino‐3,5‐dinitropyrazine‐1‐oxide based Nanocomposites
Authors: An Chongwei , Li Hequn , Geng Xiaoheng , Li Junlong , Wang Jingyu
Published: February 2013

With estane as binder, a new nanocomposite energetic material based on 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) was successfully prepared by the spray drying method. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and X‐ray diffraction (XRD) was employed to characterize the nanocomposite samples. The impact sensitivity and thermal decomposition properties of the nanocomposites were also measured and analyzed. The results show that the nanocomposite particles are spherical in shape and range from 1 μm to 10 μm in size. The composite is aggregated of many tiny granules with nucleus/shell structure, in which the shell thickness and crystal size of LLM‐105 are about 20 nm and 50–100 nm. The crystal type of LLM‐105 in the nanocomposite is similar to that of raw LLM‐105, however, the diffraction peaks become weaker and wider mainly due to decreasing of particle size. The nanocomposite has lower impact sensitivity and better thermal stability.
A DFT Study on the Structures and Energies of Isomers of 4‐Amino‐1,3‐dinitro‐1,2,4‐triazol‐5‐one‐2‐oxide: New High Energy Density Compounds
Authors: Ravi Pasupala , Tewari Surya P. , Ramaswamy Ramakrishna
Published: February 2013

Isomers of 4‐amino‐1,3‐dinitrotriazol‐5‐one‐2‐oxide (ADNTONO) are of interest in the contest of insensitive explosives and were found to have true local energy minima at the DFT‐B3LYP/aug‐cc‐pVDZ level. The optimized structures, vibrational frequencies and thermodynamic values for triazol‐5‐one N‐oxides were obtained in their ground state. Kamlet‐Jacob equations were used to evaluate the performance properties. The detonation properties of ADNTONO (D=10.15 to 10.46 km s−1, P=50.86 to 54.25 GPa) are higher compared with those of 1,1‐diamino‐2,2‐dinitroethylene (D=8.87 km s−1, P=32.75 GPa), 5‐nitro‐1,2,4‐triazol‐3‐one (D=8.56 km s−1, P=31.12 GPa), 1,2,4,5‐tetrazine‐3,6‐diamine‐1,4‐dioxide (D=8.78 km s−1, P=31.0 GPa), 1‐amino‐3,4,5‐trinitropyrazole (D=9.31 km s−1, P=40.13 GPa), 4,4′‐dinitro‐3,3′‐bifurazan (D=8.80 km s−1, P=35.60 GPa) and 3,4‐bis(3‐nitrofurazan‐4‐yl)furoxan (D=9.25 km s−1, P=39.54 GPa). The NH2 group(s) appears to be particularly promising area for investigation since it may lead to two desirable consequences of higher stability (insensitivity), higher density, and thus detonation velocity and pressure.