bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of self‐attraction and loading effects induced by shelf mass loading on projected regional sea level rise
Authors: Richter K. , Riva R.E.M. , Drange H.
Published: February 2013

We investigate the effect of self‐attraction and loading (SAL) induced by the projected accumulation of sea water on shallow continental shelf areas. Using output from a climate model, we compute 21st century changes in regional steric sea surface height and find that steric changes are largest over the deep ocean and relatively small on the shallow continental shelves. The resulting redistribution of sea water towards the shelf areas leads to mass accumulation on the shelves and therefore to increased gravitational attraction as well as increased loading on the sea floor. We find that, depending on the scenario and region, SAL effects may result in an additional sea level rise of 1–3 cm on the world's continental shelf areas by the end of the 21st century. These estimates are at most 15% of the combined changes in sea surface height induced by redistribution of water masses and steric expansion.
Mass loss of Greenland's glaciers and ice caps 2003–2008 revealed from ICESat laser altimetry data
Authors: Bolch T. , Sandberg Sørensen L. , Simonsen S. B. , Mölg N. , Machguth H. , Rastner P. , Paul F.
Published: February 2013

The recently finalized inventory of Greenland's glaciers and ice caps (GIC) allows for the first time to determine the mass changes of the GIC separately from the ice sheet using space‐borne laser altimetry data. Corrections for firn compaction and density that are based on climatic conditions are applied for the conversion from volume to mass changes. The GIC which are clearly separable from the icesheet (i.e., have a distinct ice divide or no connection) lost 27.9 ± 10.7 Gt a−1 or 0.08 ± 0.03 mm a−1 sea‐level equivalent (SLE) between October 2003 and March 2008. All GIC (including those with strong but hydrologically separable connections) lost 40.9 ± 16.5 Gt a−1 (0.12 ± 0.05 mm a−1 SLE). This is a significant fraction (~14 or 20%) of the reported overall mass loss of Greenland and up to 10% of the estimated contribution from the world's GIC to sea level rise. The loss was highest in southeastern and lowest in northern Greenland.
Synthesis and Spectroscopic Characterization of New Double‐Armed Benzo‐15‐Crown‐5 Derivatives and Their Sodium Complexes
Authors: Sahin Onur , Hayvalı Zeliha
Published: February 2013

Double‐armed crown ether aldehydes (1–3) were synthesized from the reaction of 2 equiv salicylaldehyde, 4‐hydroxy‐3‐methoxybenzaldehyde (vanillin), and 3‐hydroxy‐4‐methoxybenzaldehyde (iso‐vanillin) with 4′,5′‐bis(bromomethyl)benzo‐15‐crown‐5. New crown ethers imine compounds (4–9) were synthesized by the condensation of corresponding crown ether aldehydes (1–3) with 4‐amino‐1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3H‐pyrazole‐3‐one and 2‐furan‐2‐yl‐methylamine. Sodium complexes (1a–9a) of the crown compounds form crystalline 1:1 (Na+:ligand) stoichiometries and were also synthesized. The structures of the crown ether aldehydes (1–3), imine compounds (4–9), and complexes (1a–9a) were confirmed on the basis of elemental analyses, IR, 1H and 13C NMR, and mass spectrometry. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:100–109, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21070
A role for anterior thalamic nuclei in affective cognition: Interaction with environmental conditions
Authors: Dupire Alexandra , Kant Patricia , Mons Nicole , Marchand Alain R. , Coutureau Etienne , Dalrymple‐Alford John , Wolff Mathieu
Published: February 2013

Damage to anterior thalamic nuclei (ATN) is a well‐known cause of diencephalic pathology that produces a range of cognitive deficits reminiscent of a hippocampal syndrome. Anatomical connections of the ATN also extend to cerebral areas that support affective cognition. Enriched environments promote recovery of declarative/relational memory after ATN lesions and are known to downregulate emotional behaviors. Hence, the performance of standard‐housed and enriched ATN rats in a range of behavioral tasks engaging affective cognition was compared. ATN rats exhibited reduced anxiety responses in the elevated plus maze, increased activity and reduced corticosterone responses when exploring an open field, and delayed acquisition of a conditioned contextual fear response. ATN rats also exhibited reduced c‐Fos and phosphorylated cAMP response element‐binding protein (pCREB) immunoreactivity in the hippocampal formation and the amygdala after completion of the contextual fear test. Marked c‐Fos hypoactivity and reduced pCREB levels were also evident in the granular retrosplenial cortex and, to a lesser extent, in the anterior cingulate cortex. Unlike standard‐housed ATN rats, enriched ATN rats expressed virtually no fear of the conditioned context. These results show that the ATN regulate affective cognition and that damage to this region may produce markedly different behavioral effects as a function of environmental housing conditions. © 2013 Wiley Periodicals, Inc.
Capabilities of satellite precipitation datasets to estimate heavy precipitation rates at different temporal accumulations
Authors: Mehran Ali , AghaKouchak Amir
Published: February 2013

The importance of satellite datasets as alternative sources of precipitation information has been argued in numerous studies. Future developments in satellite precipitation algorithms as well as utilization of satellite data in operational applications rely on a more in‐depth understanding of satellite errors and biases across different spatial and temporal scales. This paper investigates the capability of satellite precipitation data sets with respect to detecting heavy precipitation rates over different temporal accumulations. In this study, the performance of Tropical Rainfall Measuring Mission real time (TRMM‐RT), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks and CPC MORPHing (CMORPH) is compared against radar‐based gauge‐adjusted Stage IV data. The results show that none of the high temporal resolution (3‐h) datasets are ideal for detecting heavy precipitation rates. In fact, the detection skill of all products drops as the precipitation thresholds (i.e. 75 and 90 percentiles) increase. At higher temporal accumulations (6, 12 and 24 h), the detection skill improves for all precipitation products, with CMORPH showing a better detection skill compared to all other products. On the other hand, all precipitation products exhibit high false alarm ratios above the heavy precipitation thresholds, although TRMM‐RT lead to a relatively smaller level of false alarms. These results indicate that further efforts are necessary to improve the precipitation algorithms so that they can capture heavy precipitation rates more reliably. Copyright © 2013 John Wiley & Sons, Ltd.
The Use of Occupational Images in Counselor Supervision
Authors: Stoltz Kevin B. , Barclay Susan R. , Reysen Rebekah H. , Degges Suzanne
Published: February 2013

Counselor supervision occurs during a critical stage when counselors‐in‐training (CITs) are actively developing their career self‐concept as they adapt to professional life and responsibilities. This article provides an application of a narrative approach for supervisors helping CITs understand how their personal occupational images interplay with adjusting to the work environment. With this understanding, CITs are able to identify aspects of the professional career image that they want to develop and portray in their pursuit of a career in counseling.
Problems of Professional Competence Among Counselor Trainees: Programmatic Issues and Guidelines
Authors: Rust Jonathan P. , Raskin Jonathan D. , Hill Melanie S.
Published: February 2013

Counselor education programs have a responsibility to ensure that individuals are competently trained, demonstrate understanding of ethical guidelines, and are free of observable psychological issues that may affect their ability to provide adequate counseling services. Counselor trainees who do not reach or maintain these professional standards may exhibit problems of professional competence (PPC). This position paper provides a review of the issues related to PPC among counselor trainees. It offers guidelines to counselor education programs for developing PPC policies and procedures. Future directions for research and training practice are discussed.
Two phytoplankton blooms near Luzon Strait generated by lingering Typhoon Parma
Authors: Zhao Hui , Han Guoqi , Zhang Shuwen , Wang Dongxiao
Published: February 2013

Two phytoplankton blooms near Luzon Strait triggered by Typhoon Parma in 2009 were investigated using remote sensing data and in situ observations. Parma was slow moving (a translation speed of ~2 m s−1) and relatively weak (a maximum sustained wind of ~30 m s−1) during its lingering path northwest of Luzon Island. After it reached a point (120.5°E, 20.3°N) west of Luzon Strait, Parma turned sharply back toward the northern Philippines along approximately the same course. Such long (~7 days) lingering typhoons are rather rare in the South China Sea (SCS). Before Parma, low Chl‐a concentrations (<0.2 mg m−3) were observed in the northeastern SCS. After its passage, a strong offshore phytoplankton increase (Chl‐a > 0.6 mg m−3) appeared west of the central Luzon Strait; a nearshore phytoplankton increase was also observed north of Luzon Island, together with high CDOM (color dissolved organic matter). During and after the typhoon, sea‐surface cooling (~3°C), stronger wind (>20 m s−1), and heavy rainfall (>100 mm day−1) were seen in the above regions. The offshore bloom occurred where Parma's translation speed was the slowest (~1 m s−1). It may be caused primarily by the Ekman pumping which brought nutrients upward to the euphotic zone and also by the entrainment mixing. The nearshore bloom may be triggered by the heavy typhoon‐induced rainfall, which supplied nutrients for the coast region north of Luzon Island. The rapid increase of CDOM in the nearshore region implied that terrestrial input may be the source of nutrients.
Usefulness of 1H‐MRS in differentiating bilirubin encephalopathy from severe hyperbilirubinemia in neonates
Authors: Wu Wulin , Zhang Ping , Wang Xiaoyi , Chineah Ashley , Lou Mingwu
Published: February 2013

Purpose:

To evaluate the usefulness of 1H‐MRS in differentiating bilirubin encephalopathy from severe hyperbilirubinemia in neonates.

Materials and Methods:

There were 11 patients enrolled in the neonatal bilirubin encephalopathy (NBE) group, 8 patients in the neonatal hyperbilirubinemia (NH) group, and 9 healthy, age‐matched neonates were included as controls. All patients and controls underwent 1H‐MRS and conventional magnetic resonance (MR) sequences. The spectroscopic regions of interest were the bilateral basal ganglia and the thalamus, and a spatial resolution of 1.0 cm3 was obtained.

Results:

Peak‐area ratios of NAA/Cr and NAA/ Cho in the basal ganglia were found to be significantly lower for the NBE group compared with the NH and control groups (P < 0.05). In contrast, there was no significant difference in the NAA/Cr ratios calculated for basal ganglia of the NH and control groups. Peak‐area ratios of NAA/Cr and NAA/Cho in the thalamus were decreased for the NBE group compared with the NH and control groups, but the differences were not significant (P > 0.05). There was a significant correlation between NAA/Cr ratios for basal ganglia and the total serum bilirubin (TSB) peak level in the NBE group (P < 0.05).

Conclusion:

1H‐MRS is useful in the differential diagnosis of NBE from severe hyperbilirubinemia in neonates, especially when the symptoms of NBE are atypical (subtle) and MRI does not reveal clear abnormalities. J. Magn. Reson. Imaging 2013;38:634–640. © 2013 Wiley Periodicals, Inc.
Towards the automatic computational assessment of enlarged perivascular spaces on brain magnetic resonance images: A systematic review
Authors: del C. Valdés Hernández Maria , Piper Rory J. , Wang Xin , Deary Ian J. , Wardlaw Joanna M.
Published: February 2013

Enlarged perivascular spaces (EPVS), visible in brain MRI, are an important marker of small vessel disease and neuroinflammation. We systematically evaluated the literature up to June 2012 on possible methods for their computational assessment and analyzed confounds with lacunes and small white matter hyperintensities. We found six studies that assessed/identified EPVS computationally by seven different methods, and four studies that described techniques to automatically segment similar structures and are potentially suitable for EPVS segmentation. T2‐weighted MRI was the only sequence that identified all EPVS, but FLAIR and T1‐weighted images were useful in their differentiation. Inconsistency within the literature regarding their diameter and terminology, and overlap in shape, intensity, location, and size with lacunes, conspires against their differentiation and the accuracy and reproducibility of any computational segmentation technique. The most promising approach will need to combine various MR sequences and consider all these features for accurate EPVS determination. J. Magn. Reson. Imaging 2013;38:774–785. © 2013 Wiley Periodicals, Inc.
Elimination of two‐photon excited fluorescence using a single‐beam coherent anti‐Stokes Raman scattering setup
Authors: Wipfler Alexander , Rehbinder Jean , Buckup Tiago , Motzkus Marcus
Published: February 2013

In this report, we demonstrate how to obtain Raman spectra from single‐beam CARS measurements under the condition of strong overlapping two‐photon excited fluorescence (2PEF). Our approach is based on the use of a narrowband phase gate implemented via femtosecond laser pulse shaping from a single broadband laser source, without any use of polarization or amplitude modulation. The decisive quantity regarding the creation of 2PEF with shaped laser pulses is the second harmonic power spectrum, which shows a different dependence on the excitation phase from the CARS signal generation. By shifting the phase or the position of the gate in an appropriate way, it is possible to keep the second harmonic power spectrum and 2PEF constant, paving the way for an elimination of it. This allows to reconstruct the Raman signal and to retrieve quantitative information of resonances even when the fluorescence is about 160 times larger than the CARS signal. Copyright © 2013 John Wiley & Sons, Ltd.
3D digital cinema technologies
Authors: Schuck Miller , Sharp Gary
Published: February 2013

We describe fundamental aspects of the two major digital cinema projector platforms with special regard to the needs of 3D cinema. We present several optical solutions for 3D digital cinema, including polarization‐converting modulators, over‐under lenses, and dual projector systems. Finally, we define a metric for 3D efficiency and compare several solutions on this basis.
Experimental treatment of dog lice infestation in interior Alaska wolf packs
Authors: Gardner Craig L. , Beckmen Kimberlee B. , Pamperin Nathan J. , Del Vecchio Patricia
Published: February 2013

Biting dog lice (Trichodectes canis) were first detected on wolves (Canis lupus) in Southcentral Alaska (USA) in 1981 introduced via domestic dogs. Lice infestation expanded north via wolf dispersal to the Tanana Flats of Interior Alaska in December 2003. Effects of this ectoparasite on wolves were persistent with moderate to severe clinical signs of pediculosis lasting multiple generations. Our objectives were to evaluate the extent of lice infestation on wolves within the Tanana Flats and develop a management program that limited further transmission. We implemented a treatment method that consisted of multiple applications of oral antiparasitic ivermectin‐injected baits aerially distributed at den and rendezvous sites during mid‐May through August. During 2005–2010, we evaluated 12–19 packs annually as part of a treatment group and 3 infested packs as a control. Infestation rates of treatment packs prior to treatment varied from 15% in 2005 (2 of 13), 50% in 2006 (7 of 14), 24% in 2007 (4 of 17), 5% in 2008 (1 of 19), and 0% in 2009–2010 (0 of 19). We treated 50%, 71%, and 75% of the infested treatment packs during 2005–2007, respectively. All treated packs were lice‐free the winter following treatment, whereas all 3 control packs remained infested. The combination of treatment and harvest successfully eliminated the local source population of lice within 3 years and we found no evidence of lice infestation within the treatment area during the last 3 years of the study. By using this treatment method, managers can eliminate dog lice infestations of wolves in areas ≤13,000 km2. By initiating treatment promptly after detection, transmission to unexposed nearby packs can be postponed and the local source population of lice on wolves eradicated. © 2013 The Wildlife Society.
Cerussite, PbCO3 – a new Stimulated Raman Scattering (SRS)‐active crystal with high‐order Stokes and anti‐Stokes lasing
Authors: Kaminskii Alexander A. , Bohatý Ladislav , Rhee Hanjo , Kaltenbach André , Lux Oliver , Eichler Hans J. , Rückamp Reinhard , Becker Petra
Published: February 2013

Orthorhombic PbCO3, known as natural crystal cerussite, is presented as a new Stimulated Raman Scattering (SRS)‐active crystal. With picosecond laser pumping high‐order Raman‐induced χ(3) generation is observed. All registered Stokes and anti‐Stokes sidebands in the visible and near‐IR are identified and attributed to the SRS‐promoting phonon mode A1g of the carbonate group, with ωSRS ≈ 1054 cm−1. The first Stokes steady‐state Raman gain coefficient in the visible spectral range is estimated as well to a value not less than 4.6 cm·GW−1.
Usefulness, Enjoyment, and Self‐Image Congruence: The Adoption of e‐Book Readers
Authors: Antón Carmen , Camarero Carmen , Rodríguez Javier
Published: February 2013

One challenge when launching new technologies is to overcome consumer resistance to change so as to accelerate market acceptance. This is the case of e‐book readers. The present study investigates individuals’ perceptions of the utilitarian and hedonic values of such devices and their congruence with self‐image as determinants of adoption. Additionally, consumer profile and familiarity with the new technology as a whole influence individuals’ perceptions of this particular technology and its congruence with self‐image. Findings show that perceived enjoyment and self‐image congruence complement perceived usefulness in forging a favorable attitude toward e‐book readers and adoption intention, and that knowledge proves essential in the adoption process. Moreover, people highly involved with reading tend to perceive e‐book readers as useless, which hampers their adoption.
Signal scaling improves the signal‐to‐noise ratio of measurements with segmented 2D‐selective radiofrequency excitations
Authors: Finsterbusch Jürgen , Busch Martin G. , Larson Peder E. Z.
Published: February 2013

Purpose

Segmented 2D‐selective radiofrequency excitations can be used to acquire irregularly shaped target regions, e.g., in single‐voxel MR spectroscopy, without involving excessive radiofrequency pulse durations. However, segments covering only outer k‐space regions nominally use reduced B1 amplitudes (i.e., smaller flip angles) and yield lower signal contributions, which decreases the efficiency of the measurement. The purpose of this study was to show that applying the full flip angle for all segments and scaling down the acquired signal appropriately (signal scaling) retains the desired signal amplitude but reduces the noise level accordingly and, thus, increases the signal‐to‐noise ratio.

Methods

The principles and improvements of signal scaling were demonstrated with MR imaging and spectroscopy experiments at 3 T for a single‐line segmentation of a blipped‐planar trajectory.

Results

The observed signal‐to‐noise ration gain depended on the 2D‐selective radiofrequency excitation's resolution, field‐of‐excitation, and its excitation profile and was between 40 and 500% for typical acquisition parameters.

Conclusion

Signal scaling can further improve the performance of measurements with segmented 2D‐selective radiofrequency excitations, e.g., for MR spectroscopy of anatomically defined voxels. Magn Reson Med 70:1491–1499, 2013. © 2013 Wiley Periodicals, Inc.
Steady‐state first‐pass perfusion (SSFPP): A new approach to 3D first‐pass myocardial perfusion imaging
Authors: Giri Shivraman , Xue Hui , Maiseyeu Andrei , Kroeker Randall , Rajagopalan Sanjay , White Richard D. , Zuehlsdorff Sven , Raman Subha V. , Simonetti Orlando P.
Published: February 2013

Purpose

To describe and characterize a new approach to first‐pass myocardial perfusion utilizing balanced steady‐state free precession acquisition without the use of saturation recovery or other magnetization preparation.

Theory

The balanced steady‐state free precession sequence is inherently sensitive to contrast agent enhancement of the myocardium. This sensitivity can be used to advantage in first‐pass myocardial perfusion imaging by eliminating the need for magnetization preparation.

Methods

Bloch equation simulations, phantom experiments, and in vivo 2D imaging studies were run comparing the proposed technique with three other methods: saturation recovery spoiled gradient echo, saturation recovery steady‐state free precession, and steady‐state spoiled gradient echo without magnetization preparation. Additionally, an acquisition‐reconstruction strategy for 3D perfusion imaging is proposed and initial experience with this approach is demonstrated in healthy subjects and one patient.

Results

Phantom experiments verified simulation results showing the sensitivity of the balanced steady‐state free precession sequence to contrast agent enhancement in solid tissue is similar to that of magnetization‐prepared acquisitions. Images acquired in normal volunteers showed the proposed technique provided superior signal and signal‐to‐noise ratio compared with all other sequences at baseline as well as postcontrast.

Conclusions

A new approach to first‐pass myocardial perfusion is presented that obviates the need for magnetization preparation and provides high signal‐to‐noise ratio. Magn Reson Med 71:133–144, 2014. © 2013 Wiley Periodicals, Inc.
Design, manufacture, and analysis of customized phantoms for enhanced quality control in small animal MRI systems
Authors: Yoshimaru Eriko , Totenhagen John , Alexander Gene E. , Trouard Theodore P.
Published: February 2013

Purpose

Magnetic resonance imaging (MRI) is widely used in human brain research to evaluate the effects of healthy aging and development, as well as neurological disorders. Although standardized methods for quality assurance of human MRI instruments have been established, such approaches have typically not been translated to small animal imaging. We present a method for the generation and analysis of customized phantoms for small animal MRI systems that allows rapid and accurate system stability monitoring.

Methods

Computer‐aided design software was used to produce a customized phantom using a rapid prototyping printer. Automated registration algorithms were used on three‐dimensional images of the phantom to allow system stability to be easily monitored over time.

Results

The design of the custom phantom allowed reliable placement relative to the imaging coil. Automated registration showed superior ability to detect gradient changes reflected in the images than with manual measurements. Registering images acquired over time allowed monitoring of gradient drifts of less than one percent.

Conclusion

A low cost, MRI compatible phantom was successfully designed using computer‐aided design software and a three‐dimensional printer. Registering phantom images acquired over time allows monitoring of gradient stability of the MRI system. Magn Reson Med 71:880–884, 2014. © 2013 Wiley Periodicals, Inc.
Knee cartilage MRI with in situ mechanical loading using prospective motion correction
Authors: Lange Thomas , Maclaren Julian , Herbst Michael , Lovell‐Smith Cris , Izadpanah Kaywan , Zaitsev Maxim
Published: February 2013

Purpose

To assess the feasibility of high resolution knee cartilage MRI with in situ mechanical loading using optical tracking to compensate for motion.

Methods

In vivo cartilage MRI with in situ mechanical loading is demonstrated on a clinical 3T system for the patellofemoral as well as for the tibiofemoral knee joint using a T1‐weighted spoiled three‐dimensional gradient‐echo sequence. Prospective motion correction is performed with a moiré phase tracking system consisting of an in‐bore camera and a single tracking marker attached to the skin.

Results

Rigid‐body approximation required for prospective correction with optical motion tracking is fulfilled well enough for the patellofemoral as well as for the tibiofemoral joint when the tracking marker is attached to the knee cap and the shin, respectively. Presaturation proves to be efficient in suppressing pulsation artifacts from the popliteal artery and residual motion artifacts primarily arising from nonrigid motion of the posterior knee compartment.

Conclusion

The proposed technique enables knee cartilage imaging under in situ mechanical loading with submillimeter spatial resolution devoid of significant motion artifacts and thus appropriate for cartilage volumetry. It has the potential to provide new insight into the biomechanics of the knee and might complement the panoply of diagnostic MR methods for osteoarthritis. Magn Reson Med 71:516–523, 2014. © 2013 Wiley Periodicals, Inc.
Fast accurate MR thermometry using phase referenced asymmetric spin‐echo EPI at high field
Authors: Streicher Markus N. , Schäfer Andreas , Ivanov Dimo , Müller Dirk K. , Amadon Alexis , Reimer Enrico , Huber Laurentius , Dhital Bibek , Rivera Debra , Kögler Carsten , Trampel Robert , Pampel André , Turner Robert
Published: February 2013

Purpose

A novel highly accurate method for MR thermometry, effective at high field, is introduced and validated, which corrects for slow and fast field fluctuations by means of reference images.

Methods

An asymmetric spin‐echo echo planar imaging sequence was made frequency‐selective to water or a reference substance by controlling the slice‐select gradient polarity and the duration of the excitation and refocusing radiofrequency pulses. Images were acquired pairwise, and the temperature‐sensitive water images were corrected for field fluctuations using the reference images. In a phantom radiofrequency heating experiment, dissolved dimethyl sulfoxide was used as a reference substance. Temperature stability was tested in vivo on the human brain, referenced using subcutaneous scalp fat. Water and fat phase images were acquired only 50 ms apart. Bloch simulations validated the frequency selection accuracy.

Results

Asymmetric spin‐echo imaging using a simple frequency selection method provides highly accurate referenced MR thermometry in phantoms and in vivo at 7 T. Effects of field fluctuations caused by field drift, breathing, and heart beat were corrected. The technique is highly robust against B1 inhomogeneities.

Conclusion

Frequency selection using gradient‐reversal can enable fast accurate referenced in vivo MR thermometry, assisting thermal characterization of radiofrequency coils and possibly in vivo SAR monitoring. Magn Reson Med 71:524–533, 2014. © 2013 Wiley Periodicals, Inc.
Dynamic contrast‐enhanced MRI in mice at high field: Estimation of the arterial input function can be achieved by phase imaging
Authors: Fruytier A.‐C. , Magat J. , Colliez F. , Jordan B. , Cron G. , Gallez B.
Published: February 2013

Purpose

Quantitative dynamic contrast‐enhanced MRI requires an accurate arterial input function (AIF). At high field, increased susceptibility effects and decreased longitudinal relaxivity of contrast agents lead to predominant T2* effects in blood vessels, producing a dip in signal during passage of the contrast agent bolus. This study determined phase‐derived AIFs in mice at 11.7 T.

Methods

AIFs were measured in aorta/vena cava for five FBV/N mice and in iliac arteries/veins for five NMRI mice with a fast low angle shot sequence, simultaneously with tumor imaging (temporal resolution: 1.19 s). Gadoterate was injected into the tail vein as a bolus (0.286 mmol Gd/kg). An in vitro study was also performed to calculate the relationship between ΔΦ and gadolinium concentration.

Results

The phantom system confirmed the linear relationship between measured ΔΦ and gadolinium concentration. In vivo, a dip in arterial magnitude signal made it impossible to quantify the AIF. With phase imaging, a clear quantifiable bolus peak was obtained; peak measured concentration in plasma was 4.9 ± 0.9 mM for FBV/N mice and 8.0 ± 0.6 mM for NMRI mice, close to the expected concentration of 6.8 mM.

Conclusion

Phase imaging seems to be an appropriate means to measure the AIF of mice at high field. Magn Reson Med 71:544–550, 2014. © 2013 Wiley Periodicals, Inc.
Accelerated isotropic sub‐millimeter whole‐heart coronary MRI: Compressed sensing versus parallel imaging
Authors: Akçakaya Mehmet , Basha Tamer A. , Chan Raymond H. , Manning Warren J. , Nezafat Reza
Published: February 2013

Purpose

To enable accelerated isotropic sub‐millimeter whole‐heart coronary MRI within a 6‐min acquisition and to compare this with a current state‐of‐the‐art accelerated imaging technique at acceleration rates beyond what is used clinically.

Methods

Coronary MRI still faces major challenges, including lengthy acquisition time, low signal‐to‐noise‐ratio (SNR), and suboptimal spatial resolution. Higher spatial resolution in the sub‐millimeter range is desirable, but this results in increased acquisition time and lower SNR, hindering its clinical implementation. In this study, we sought to use an advanced B1‐weighted compressed sensing technique for highly accelerated sub‐millimeter whole‐heart coronary MRI, and to compare the results to parallel imaging, the current‐state‐of‐the‐art, where both techniques were used at acceleration rates beyond what is used clinically. Two whole‐heart coronary MRI datasets were acquired in seven healthy adult subjects (30.3 ± 12.1 years; 3 men), using prospective 6‐fold acceleration, with random undersampling for the proposed compressed sensing technique and with uniform undersampling for sensitivity encoding reconstruction. Reconstructed images were qualitatively compared in terms of image scores and perceived SNR on a four‐point scale (1 = poor, 4 = excellent) by an experienced blinded reader.

Results

The proposed technique resulted in images with clear visualization of all coronary branches. Overall image quality and perceived SNR of the compressed sensing images were significantly higher than those of parallel imaging (P = 0.03 for both), which suffered from noise amplification artifacts due to the reduced SNR.

Conclusion

The proposed compressed sensing‐based reconstruction and acquisition technique for sub‐millimeter whole‐heart coronary MRI provides 6‐fold acceleration, where it outperforms parallel imaging with uniform undersampling. Magn Reson Med 71:815–822, 2014. © 2013 Wiley Periodicals, Inc.
The dynamics of the marine nitrogen cycle across the last deglaciation
Authors: Eugster Olivier , Gruber Nicolas , Deutsch Curtis , Jaccard Samuel L. , Payne Mark R.
Published: February 2013

We use a geochemical box model to investigate the changes in marine N‐fixation and denitrification required to match the observed sedimentary δ15N changes between ∼ 30 kyr B.P. and the late Holocene. This is achieved by optimizing a set of seven parameters that describe the strengths of three ocean‐internal N feedbacks and the response of the oceanic N cycle to four external forcings. Scenarios that best match the δ15N constraints indicate a strong transient decrease in N‐fixation in the early deglacial in response to the decrease in iron input by dust. Around 15 kyr B.P., N‐fixation rebounds primarily in response to an abrupt increase in water column denitrification caused by an expansion of anoxia. Benthic denitrification is not well constrained by our model but tends to increase in sync with water column denitrification. As a result of the transient imbalance between N‐fixation and denitrification, we infer a glacial‐to‐interglacial decrease in the marine N inventory of between 15 and 50%. The model diagnoses this reduction in order to simultaneously fit the data from all ocean basins, requiring it to reduce the degree by which water column denitrification in the oxygen minimum zones is influencing the δ15N of nitrate of the whole ocean (dilution effect). Our optimal solution suggests a glacial N cycle that operated at nearly the same rates as that in pre‐industrial times, but sensitivity cases with substantially lower rates fit the data only marginally worse. An important caveat of our study is the assumption of an unchanging ocean circulation. An initial sensitivity experiment shows that this affects primarily the magnitude of the change in the N inventory, while the diagnosed deglacial dynamics with global marine N‐fixation taking a dip before the onset of denitrification remains a robust result.
A novel phenotype variant of severe congenital neutropenia caused by G6PC3 deficiency
Authors: Estévez Orlando A. , Ortega Consuelo , Tejero Ángeles , Fernández Silvia , Aguado Rocío , Aróstegui Juan I. , González‐Roca Eva , Peña José , Santamaría Manuel
Published: February 2013

Severe congenital neutropenia type 4 (SCN4) is associated with mutations in the G6PC3 gene. To date, all patients bearing the p.Gly260Arg variant of the G6PC3 gene show heart defects. Here, we present a case of the p.Gly260Arg variant in a patient who did not have structural or functional heart anomalies. Treatment with granulocyte colony‐stimulating factor recovered the absolute neutrophil count and neutrophil functional competence. Pediatr Blood Cancer 2013; 60: E29–E31. © 2013 Wiley Periodicals, Inc.
Selective isolation and analysis of glycoprotein fractions and their glycomes from hepatocellular carcinoma sera
Authors: Yang Ganglong , Cui Ting , Wang Ye , Sun Shisheng , Ma Tianran , Wang Ting , Chen Qiaoling , Li Zheng
Published: February 2013

As one of the most important post‐translational modifications, the discovery, isolation, and identification of glycoproteins are becoming increasingly important. In this study, a Con A‐magnetic particle conjugate‐based method was utilized to selectively isolate the glycoproteins and their glycomes from the healthy donor and hepatocellular carcinoma (HCC) case sera. The isolated glycoproteins and their N‐linked glycans were identified by LC‐ESI‐MS/MS and MALDI‐TOF/TOF‐MS, respectively. A total of 93 glycoproteins from the healthy donors and 85 glycoproteins from the HCC cases were identified. There were 34 different glycoproteins shown between the healthy donors (21/34) and the HCC cases (13/34). Twenty‐eight glycans from the healthy donors and 30 glycans from the HCC cases were detected and there were 22 different glycans shown between the healthy donors (10/22) and HCC cases (12/22). Among these glycoproteins, 50 were known to be N‐linked glycoproteins and three novel glycopeptides from two predicted potential glycoproteins were discovered. Moreover, lectin blotting, Western blotting and lectin/glyco‐antibody microarrays were applied to definitely elucidate the change of selective protein expressions and their glycosylation levels, the results indicated that the differences of the identified glycoproteins between the healthy donors and HCC cases were caused by the change of both protein expression and their glycosylation levels.
Unmet needs of Australian and Canadian haematological cancer survivors: a cross‐sectional international comparative study
Authors: Hall Alix , Campbell H. Sharon , Sanson‐Fisher Rob , Lynagh Marita , D'Este Catherine , Burkhalter Robin , Carey Mariko
Published: February 2013

Objective

Few population‐based studies have assessed the needs of haematological cancer survivors or conducted international comparisons. We aimed to assess and compare the unmet needs of Australian and Canadian haematological cancer survivors.

Methods

Two cross‐sectional datasets were analysed. Survivors were recruited from population‐based cancer registries and sent a self‐report survey containing the Survivors Unmet Needs Survey. Australians were aged 18–80 years at the time of study and diagnosed in the last 3 years. Canadians were diagnosed 1–5 years prior and aged 19 years and over at diagnosis.

Results

A total of 268 Australian and 169 Canadian survivors returned a completed survey. ‘Dealing with feeling tired’ was identified as the highest concern by survivors. Country (LRχ2 = 4.0(1), p = 0.045) was associated with survivors reporting a ‘high/very high’ unmet need with ‘worry about earning money,’ with Australians reporting marginally nonsignificantly higher odds than Canadians (OR 2.1; 95% CI; 0.99, 4.3). Country was not significantly associated with any other outcome. Having a personal expense in the last month as a result of having cancer, younger age at diagnosis, female sex, vocational or other level education, and consulting a health care professional for cancer treatment or concerns about cancer in the last month were associated with multiple areas of need.

Conclusions

Australian and Canadian haematological cancer survivors were found to experience similar levels of unmet needs. Overall, haematological cancer survivors may require additional assistance in dealing with feeling tired. Copyright © 2013 John Wiley & Sons, Ltd.
Mass spectrometry‐based methods to study protein architecture and dynamics
Authors: Kaltashov Igor A. , Bobst Cedric E. , Abzalimov Rinat R.
Published: February 2013

Mass spectrometry is now an indispensable tool in the armamentarium of molecular biophysics, where it is used for tasks ranging from protein sequencing and mapping of post‐translational modifications to studies of higher order structure, conformational dynamics, and interactions of proteins with small molecule ligands and other biopolymers. This mini‐review highlights several popular mass spectrometry‐based tools that are now commonly used for structural studies of proteins beyond their covalent structure with a particular emphasis on hydrogen exchange and direct electrospray ionization mass spectrometry.
Human enteropeptidase light chain: Bioengineering of recombinants and kinetic investigations of structure and function
Authors: Smith Eliot T. , Johnson David A.
Published: February 2013

The serine protease enteropeptidase exhibits a high level of substrate specificity for the cleavage sequence DDDDK∼ X, making this enzyme a useful tool for the separation of recombinant protein fusion domains. In an effort to improve the utility of enteropeptidase for processing fusion proteins and to better understand its structure and function, two substitution variants of human enteropeptidase, designated R96Q and Y174R, were created and produced as active (>92%) enzymes secreted by Pichia pastoris with yields in excess of 1.7 mg/Liter. The Y174R variant showed improved specificities for substrates containing the sequences DDDDK (kcat/KM = 6.83 × 106
M−1
sec−1) and DDDDR (kcat/KM = 1.89 × 107
M−1 sec−1) relative to all other enteropeptidase variants reported to date. BPTI inhibition of Y174R was significantly decreased. Kinetic data demonstrate the important contribution of the positively charged residue 96 to extended substrate specificity in human enteropeptidase. Modeling shows the importance of the charge–charge interactions in the extended substrate binding pocket.
Nanocrystalline electroplated NiFe‐based alloys for integrated magnetic microsensors
Authors: Theis Martin , Ediger Simon , Schmitt Martin Tobias , Hoffmann Joachim‐Ernst , Saumer Monika
Published: February 2013

The effect of pulse plating (PF) and direct current (DC) plating on the magnetic properties and grain size of electroplated NiFe films for the application in magnetic microsensors, i.e., as integrated magnetic concentrator, has been studied. In order to further improve magnetic properties additional subsequent thermal annealing experiments were carried out with chosen films. A sulphate‐based NiFe electrolyte containing various additives operated at a pH of 3.5 and a temperature of 50 °C was used. The softmagnetic NiFe films were deposited at a thickness of >10 µm on silicon substrates with a sputtered 200 nm thick Cu seed layer and a 50 µm high photoresist mould. The composition and magnetic properties were measured by energy dispersive X‐ray spectroscopy (EDX) and vibrating sample magnetometer (VSM), respectively. The morphology was investigated by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The composition of the fabricated fcc NiFe films ranged from 3 to 42 wt% Fe with a good adhesion. The as‐plated NiFe exhibited nanocrystalline grain sizes ranging from 12 to 18 nm with a coercivity as low as 16 A m−1. It was found that the grain size is generally higher at a lower iron content. However, pulse forward (PF) plating favours a refined grain size over DC plating which can be attributed to an increased nucleation rate caused by the high pulse current densities (high overpotential). By applying a thermal annealing for 2 h at 300 °C in a vacuum oven the coercivity of NiFe samples with ∼18.5 wt% Fe could be further reduced to 6 A m−1.
Heat treatment and substrate dependant properties of titania thin films with high copper loading
Authors: Joost Urmas , Pärna Rainer , Lembinen Meeri , Utt Kathriin , Kink Ilmar , Visnapuu Meeri , Kisand Vambola
Published: February 2013

Copper‐doped titania thin films have been prepared on SiO2/Si(100), fused‐silica and soda‐lime glass substrates by using sol–gel deposition and subsequent annealing in air atmosphere at 200–900 °C. Several experimental techniques [X‐ray photoelectron spectroscopy (XPS), wavelength dispersive X‐ray fluorescence (WDXRF), Raman spectroscopy, atomic force microscopy (AFM), UV–Vis spectroscopy, energy dispersive X‐ray analysis (EDX), photocatalytic activity measurements and hydrophilicity measurements] have been applied to characterize these films. The results demonstrate that the films prepared on SiO2/Si(100) and fused‐silica substrates start to crystallize after annealing above 300 °C, then anatase phase is formed. At 700 °C anatase content starts to decrease and from 800 °C the films consist of rutile. Annealing causes a formation of regions with increased Cu concentration, in case of titania films prepared on SiO2/Si(100) substrates. On the other hand films prepared on soda‐lime glass substrates show large sodium diffusion into the films, the crystalline nature of the films decreases during annealing and outward segregation of copper compounds does not occur. However, the surface of copper‐doped titania films on soda‐lime glass appear to be naturally hydrophilic (i.e. surface is hydrophilic without UV irradiation), water droplet contact angles as low as 4.2° were achieved. Influence of annealing time and copper‐doping to the photocatalytic activity of thin titania films was also studied by using two organic dyes as model contaminants.
Suppression of threshold voltage shifts in organic thin‐film transistors with bilayer gate dielectrics
Authors: Fukuda Kenjiro , Suzuki Tatsuya , Kobayashi Takuma , Kumaki Daisuke , Tokito Shizuo
Published: February 2013

Bias‐stress effects in pentacene thin‐film transistors (TFT) with parylene‐C and amorphous fluoropolymers as bilayer gate dielectric layers are systematically investigated. The threshold voltage shift can be controlled systematically by changing the thicknesses of the two dielectric layers. The shift is proportional to a proportion of a potential drop between parylene‐C layer to the total potential drop between gate and source electrodes, and the threshold voltage shift can be fitted to a sum of the exponential functions. Devices with optimized thicknesses of the bilayer gate dielectrics show remarkable stability under continuous gate‐bias voltage stress over long periods, demonstrating shifts in threshold voltage of less than 0.5 V after 48 h.
Elucidating elementary processes at Cu/ZnO interfaces: A microscopical approach
Authors: Zychma Andreas , Wansing Renate , Schott Vadim , Köhler Ulrich , Wöll Christof , Muhler Martin , Birkner Alexander
Published: February 2013

Despite its enormous importance for heterogeneous catalysis, and in particular methanol synthesis, detailed information about the Cu/ZnO interface is still far from being complete. Here we present an overview of recent work carried out using different types of microscopical methods from which the complexity of the problem becomes apparent. In addition to results from transmission electron microscopy (TEM) and scanning electron microscopy (SEM) data also obtained using scanning probe techniques, in particular scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are presented. Special attention is paid to the influence of elevated temperatures on the Cu/ZnO interface.
Assessment and the logic of instructional practice in Secondary 3 English and mathematics classrooms in Singapore
Authors: Hogan David , Chan Melvin , Rahim Ridzuan , Kwek Dennis , Maung Aye Khin , Loo Siok Chen , Sheng Yee Zher , Luo Wenshu
Published: February 2013

By any measure, Singapore's educational system has generated an extraordinary record of achievement over the past two or three decades. In this article, we report on one key component of a broader three year investigation into why Singapore has done so well, and explore the logic, strength, resilience and limits of the underlying pedagogical model and policy framework that have helped secure this record of achievement. Specifically, we draw on data we collected in 2010 to analyze the pedagogical organization of four theoretically specified ‘models’ of instructional strategy–traditional instruction, direct instruction, teaching for understanding, and co‐regulated learning strategies–in Secondary 3 mathematics and English. In the course of our analysis, we develop three arguments. The first is the single‐minded performative orientation of instructional practices generally–and instructional strategies specifically–in Singaporean classrooms that rarely deviated from a logic of curriculum coverage, knowledge transmission and assessment. Second, while we found substantial evidence of a pervasive performative orientation to instruction, we also found that teachers in Singapore draw from a variety of instructional perspectives in ways that reflect a pragmatic, instrumental fit‐for‐purpose approach and broader performative orientation. Third, we found that the national high stakes assessment system, by virtue of its considerable institutional authority, both shaped the pattern of instructional practice at the classroom level and constrained opportunities for instructional improvement. In the conclusion, we review related findings from the research program on the impact of instructional practice on student achievement in Singapore.
Report on an assessment experience based on ISO/IEC 29110
Authors: Takeuchi Motoko , Kohtake Naohiko , Shirasaka Seiko , Koishi Yumi , Shioya Kazunori
Published: February 2013

In January 2011, a new standard ISO/IEC 29110 was published. To evaluate effectiveness of the assessment using ISO/IEC 29110, we have performed a series of lightweight assessment. The lightweight assessment method taken in this trial was using the task checklist based on ISO/IEC 29110‐5 with the customized procedures based on ISO/IEC 15504‐2. Through the trial, we found that the lightweight assessment required little effort to the project. Moreover, we found that the lightweight assessment was an acceptable way for the project to extract issues and risks in the project and urge awareness. Regarding the one aforementioned, the lightweight assessment using ISO/IEC 29110 has two benefits. Firstly, it is useful for the readiness checking of forthcoming tasks and workproducts. Secondly, the lightweight assessment are performed iteratively and repeatedly performed several times with little effort. As mentioned earlier, lightweight assessment should be performed not for the evaluation but as a daily routine tool to obtain the actual status and performance of management and to identify the problems. In this way, the ISO/IEC 29110 lightweight assessment is useful. Copyright © 2013 John Wiley & Sons, Ltd.