bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative lung perfusion evaluation using fourier decomposition perfusion MRI
Authors: Kjørstad Åsmund , Corteville Dominique M.R. , Fischer Andre , Henzler Thomas , Schmid‐Bindert Gerald , Zöllner Frank G. , Schad Lothar R. 
Published: September 2013

PurposeTo quantitatively evaluate lung perfusion using Fourier decomposition perfusion MRI. The Fourier decomposition (FD) method is a noninvasive method for assessing ventilation‐ and perfusion‐related information in the lungs, where the perfusion maps in particular have shown promise for clinical use. However, the perfusion maps are nonquantitative and dimensionless, making follow‐ups and direct comparisons between patients difficult. We present an approach to obtain physically meaningful and quantifiable perfusion maps using the FD method.MethodsThe standard FD perfusion images are quantified by comparing the partially blood‐filled pixels in the lung parenchyma with the fully blood‐filled pixels in the aorta. The percentage of blood in a pixel is then combined with the temporal information, yielding quantitative blood flow values. The values of 10 healthy volunteers are compared with SEEPAGE measurements which have shown high consistency with dynamic contrast enhanced‐MRI.ResultsAll pulmonary blood flow (PBF) values are within the expected range. The two methods are in good agreement (mean difference = 0.2 mL/min/100 mL, mean absolute difference = 11 mL/min/100 mL, mean PBF‐FD = 150 mL/min/100 mL, mean PBF‐SEEPAGE = 151 mL/min/100 mL). The Bland‐Altman plot shows a good spread of values, indicating no systematic bias between the methods.ConclusionQuantitative lung perfusion can be obtained using the Fourier Decomposition method combined with a small amount of postprocessing. Magn Reson Med 72:558–562, 2014. © 2013 Wiley Periodicals, Inc.
An improved trap design for decoupling multinuclear RF coils
Authors: Meyerspeer Martin , Roig Eulalia Serés , Gruetter Rolf , Magill Arthur W. 
Published: September 2013

PurposeMultinuclear magnetic resonance spectroscopy and imaging require a radiofrequency probe capable of transmitting and receiving at the proton and non‐proton frequencies. To minimize coupling between probe elements tuned to different frequencies, LC (inductor‐capacitor) traps blocking current at the 1H frequency can be inserted in non‐proton elements. This work compares LC traps with LCC traps, a modified design incorporating an additional capacitor, enabling control of the trap reactance at the low frequency while maintaining 1H blocking.MethodsLosses introduced by both types of trap were analysed using circuit models. Radiofrequency coils incorporating a series of LC and LCC traps were then built and evaluated at the bench. LCC trap performance was then confirmed using 1H and 13C measurements in a 7T human scanner.ResultsLC and LCC traps both effectively block interaction between non‐proton and proton coils at the proton frequency. LCC traps were found to introduce a sensitivity reduction of 5±2%, which was less than half of that caused by LC traps.ConclusionSensitivity of non‐proton coils is critical. The improved trap design, incorporating one extra capacitor, significantly reduces losses introduced by the trap in the non‐proton coil. Magn Reson Med 72:584–590, 2014. © 2013 Wiley Periodicals, Inc.
Phase reconstruction from multiple coil data using a virtual reference coil
Authors: Parker Dennis L. , Payne Allison , Todd Nick , Hadley J. Rock 
Published: September 2013

PurposeThis study develops a method to obtain optimal estimates of absolute magnetization phase from multiple‐coil MRI data.Theory and MethodsThe element‐specific phases of a multi‐element receiver coil array are accounted for by using the phase of a real or virtual reference coil that is sensitive over the entire imaged volume. The virtual‐reference coil is generated as a weighted combination of measurements from all receiver coils. The phase‐corrected multiple coil complex images are combined using the inverse covariance matrix. These methods are tested on images of an agar phantom, an in vivo breast, and an anesthetized rabbit obtained using combinations of four, nine, and three receiver channels, respectively.ResultsThe four‐ and three‐channel acquisitions require formation of a virtual‐reference receiver coil while one channel of the nine‐channel receive array has a sensitivity profile covering the entire imaged volume. Referencing to a real or virtual coil gives receiver phases that are essentially identical except for the individual receiver channel noise. The resulting combined images, which account for receiver channel noise covariance, show the expected reduction in phase variance.ConclusionThe proposed virtual reference coil method determines a phase distribution for each coil from which an optimal phase map can be obtained. Magn Reson Med 72:563–569, 2014. © 2013 Wiley Periodicals, Inc.
Flow compensated quantitative susceptibility mapping for venous oxygenation imaging
Authors: Xu Bo , Liu Tian , Spincemaille Pascal , Prince Martin , Wang Yi 
Published: September 2013

PurposeVenous blood oxygen saturation is an indicator of brain oxygen consumption and can be measured directly from quantitative susceptibility mapping (QSM) by deconvolving the MR phase signal. However, accurate estimation of the susceptibility of blood may be affected by flow induced phase in the presence of imaging gradient and the inhomogeneous susceptibility field gradient. The purpose of this study is to correct the flow induced error in QSM for improved venous oxygenation quantification.MethodsFlow compensation is proposed for QSM by using a fully flow compensated multi‐echo gradient echo sequence for data acquisition. A quadratic fit of the phase with respect to echo time is employed for the flow phase in the presence of inhomogeneity field gradients. Phantom and in vivo experiments were carried out to validate the proposed method.ResultsPhantom experiments demonstrated reduced error in the estimated field map and susceptibility map. Initial data in in vivo human imaging demonstrated improvements in the quantitative susceptibility map and in the estimated venous oxygen saturation values.ConclusionFlow compensated multi‐echo acquisition and an adaptive‐quadratic fit of the phase images improves the quantitative susceptibility map of blood flow. The improved vein susceptibility enables in vivo measurement of venous oxygen saturation throughout the brain. Magn Reson Med 72:438–445, 2014. © 2013 Wiley Periodicals, Inc.
High‐resolution ultrasound visualization of the subcutaneous nerves of the forearm: A feasibility study in anatomic specimens
Authors: Moritz Thomas , Prosch Helmut , Pivec Christopher H. , Sachs Alexander , Pretterklieber Michael L. , Kriechbaumer Lukas , Happak Wolfgang , Bodner Gerd 
Published: September 2013

ABSTRACTIntroduction: The aim of this ultrasound‐anatomical study was to evaluate the ability of high‐resolution ultrasound (HRUS) to visualize and infiltrate small subcutaneous nerves of the forearm in anatomic specimens. Methods: Seven nonembalmed human bodies (4 men, 3 women; mean age at death, 60 years) were included in the study. Two investigators scanned the anatomic specimens using 15‐MHz and 18‐MHz HRUS transducers. The lateral, medial, and posterior antebrachial cutaneous nerves were scanned and interventionally marked with ink using HRUS‐guidance. Subsequently, dissections were performed to assess the anatomical correlation of HRUS findings. Results: All 3 nerves were identified consistently using HRUS. The precision of the ink‐markings was excellent, with good correlation with the small peripheral branches of all 3 nerves. Conclusions: HRUS can identify precisely the small subcutaneous nerves of the forearm and may aid in both diagnosis and therapy in cases of neuropathy. Muscle Nerve 49: 676–679, 2014
Electrodiagnostic features of true neurogenic thoracic outlet syndrome
Authors: Tsao Bryan E. , Ferrante Mark A. , Wilbourn Asa J. , Shields Robert W. 
Published: September 2013

ABSTRACTIntroduction: We report the electrodiagnostic (EDX) features of 32 patients with surgically verified true neurogenic thoracic outlet syndrome (TN‐TOS). Methods: Retrospective record review. Results: We found uniform EDX evidence of a chronic axon loss process that affected the lower portion of the brachial plexus and disproportionately involved the T1 more than the C8 sensory and motor fibers. Because of this relationship, the medial antebrachial cutaneous sensory nerve (T1) and median motor (T1 > C8) study combination was abnormal in 89%, whereas response combinations that primarily assessed the C8 fibers were less frequently affected. Conclusions: The characteristic EDX features of TN‐TOS are T1 > C8 nerve fiber involvement. A comprehensive EDX examination of the lower plexus with contralateral comparison studies is imperative to diagnose this disorder accurately. Muscle Nerve 49: 724–727, 2014
Pathophysiology of immune‐mediated demyelinating neuropathies—part I: Neuroscience
Authors: Franssen Hessel , Straver Dirk C.G. 
Published: September 2013

ABSTRACTThis first article of this review deals with neuroscientific aspects of immune‐mediated demyelinating neuropathies. It describes the anatomy and physiology of normal myelinated axons, methods of studying peripheral nerve physiology, pathophysiological consequences of demyelination or damage at the node of Ranvier, and the mechanisms that may lead to impaired axonal membrane dysfunction or axonal degeneration. This article (part I) will be followed by a second (part II) dealing with clinical aspects of these neuropathies. Muscle Nerve 48: 851–864, 2013
Preclinical evaluation of the PARP inhibitor, olaparib, in combination with cytotoxic chemotherapy in pediatric solid tumors
Authors: Norris Robin E. , Adamson Peter C. , Nguyen Vu T. , Fox Elizabeth 
Published: September 2013

AbstractBackgroundPoly(ADP‐ribose) polymerase (PARP) signals DNA damage and facilitates DNA repair. PARP inhibitors are being evaluated in cancers with defective DNA repair mechanisms or in combination with cytotoxic therapy or radiation. We evaluated the PARP inhibitor, olaparib, in combination with chemotherapy using in vitro and in vivo pediatric solid tumor models.ProcedureThe IC50 of olaparib alone and in combination with cytotoxic agents was determined in 10 pediatric solid tumor cell lines. Synergy was assessed using the combination index of Chou‐Talalay. Olaparib alone and in combination with topotecan/cyclophosphamide was evaluated in xenograft models of Ewing sarcoma (RD‐ES) and neuroblastoma (NGP). PAR activity was evaluated in cell lines and tumor lysates.ResultsOlaparib induced growth inhibition, median (range) IC50 = 3.6 (1–33.8) µM, and inhibited PAR activity in pediatric solid tumor cell lines. The addition of olaparib to DNA damaging agents resulted in additive to synergistic interactions. In RD‐ES and NGP xenografts, olaparib inhibited PAR activity by 88–100% as a single agent and 100% when administered with cyclophosphamide/topotecan. Although the addition of olaparib did not antagonize the activity of cyclophosphamide/topotecan, clear evidence of synergy could not be demonstrated.ConclusionsIn pediatric solid tumor cell lines, clinically achievable concentrations of single agent olaparib caused growth inhibition. Although the in vitro data demonstrated synergistic efficacy of olaparib when added to the camptothecins and alkylating agents, synergy was not discernible in vivo. Clinical trials of PARP inhibitors in combination DNA damaging agents are necessary to establish the role of PARP inhibitors in childhood cancer. Pediatr Blood Cancer 2014;61:145–150. © 2013 Wiley Periodicals, Inc.
Determining the predictive value of Read codes to identify congenital cardiac malformations in the UK Clinical Practice Research Datalink
Authors: Hammad Tarek A. , Margulis Andrea V. , Ding Yulan , Strazzeri Marian M. , Epperly Holly 
Published: September 2013

ABSTRACTPurposesThe purposes of this study were to determine (i) the positive predictive value (PPV) of multiple Read codes used to identify congenital cardiac malformation (CCM) cases in the UK Clinical Practice Research Datalink (CPRD); (ii) the accuracy of the diagnosis date; and (iii) the source of information that the general practitioners (GPs) use for validating the diagnosis suggested by the code.MethodsEight hundred eighty‐eight records with Read diagnostic and procedures codes for CCM, between January 1996 and November 2010, were identified from CPRD. Questionnaires were sent to GPs to verify the diagnoses and date of the code‐identified events.ResultsA total of 719 questionnaires were returned (81% response rate). The PPV of the CCM codes was 93% (670/719). Thirty‐one percent of cases had a different event date than the one recorded in the electronic medical record (EMR); 10% of these differing dates were within 30 days of the code‐identified CCM date. GPs used a variety of data sources to confirm CCM diagnoses. Although the EMR was the most frequently used data source (70%), 66% reported using consultation letters, 9% reported using clinical notes or paper charts, and 35% of GPs reported using the hospital record to confirm the CCM diagnosis.ConclusionsClinical Practice Research Datalink Read codes for CCMs have 93% PPV and most likely point to true cases. However, the accuracy of diagnosis dates and the age at diagnosis may not be as reliable. The findings of this study indicate that GPs use information beyond what is available for researchers in the EMR to confirm clinical diagnoses when responding to validation questionnaires. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
NMR study of photo‐crosslinked solid polymer electrolytes: The influence of monofunctional oligoethers
Authors: Chiappone Annalisa , Jeremias Sebastian , Bongiovanni Roberta , Schönhoff Monika 
Published: September 2013

ABSTRACTSolid polymer electrolytes for Lithium batteries applications are commonly prepared by dissolving a lithium salt in poly(ethylene oxide) (PEO)‐based materials. Their performance is strongly related to the structure of the polymer network. In this article, a new salt‐in‐polymer electrolyte prepared by the fast and easy radical photopolymerization of PEO acrylate oligomers is studied. Here, a difunctional monomer used as the polymer backbone is copolymerized with monofunctional monomers of different length and concentration. Thus, the crosslinking density and conductivity are changed. These systems are investigated by a detailed NMR study yielding local dynamics and mass transport by temperature‐dependent spin‐lattice relaxation time and PFG‐NMR diffusion measurements for different nuclei (7Li and 19F). The results indicate that a sufficiently long monofunctional oligoether improves the properties, since it provides a lower crosslinking density as well as more coordinating oxygens for the Li ions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1571–1580
Social problem solving and social performance after a group social skills intervention for childhood brain tumor survivors
Authors: Schulte Fiona , Vannatta Kathryn , Barrera Maru 
Published: September 2013

AbstractPurposeThe aim of this study was to explore the ability of a group social skills intervention program for childhood brain tumor survivors to effect two steps of the social information processing model: social problem solving and social performance.MethodsParticipants were 15 survivors (eight men and seven women) aged 7–15 years. The intervention consisted of eight 2‐h weekly sessions focused on social skills including friendship making. Social problem solving, using hypothetical scenarios, was assessed during sessions 1 and 8. Social performance was observed during intervention sessions 1, 4, and 8.ResultsCompared with session 1, significant increases were found in social performance: frequency of maintaining eye contact and social conversations with peers over the course of the intervention. No significant changes in social problem solving were noted.ConclusionsThis pilot study is the first to report improvements related to group social skills intervention at the level of observed social performance over the course of intervention. The lack of change in social problem solving suggests that survivors may possess the social knowledge required for social situations but have difficulty enacting social behaviors. Copyright © 2013 John Wiley & Sons, Ltd.
Admixture mapping of prostate cancer in African Americans participating in the North Carolina‐Louisiana Prostate Cancer Project (PCaP)
Authors: Bensen Jeannette T. , Xu Zongli , McKeigue Paul M. , Smith Gary J. , Fontham Elizabeth T.H. , Mohler James L. , Taylor Jack A. 
Published: September 2013

AbstractBACKGROUNDFew genetic risk factors have been uncovered that contribute specifically to the racial disparity in prostate cancer (CaP) observed in African Americans (AA). With the advent of ancestry informative marker (AIM) single nucleotide polymorphism (SNP) panels and powerful genetic strategies such as mapping by admixture linkage disequilibrium (MALD) it is possible to discover genes that underlie ethnic variation in disease risk.METHODSOne thousand one hundred thirty AA CaP cases enrolled in the North Carolina‐Louisiana Prostate Cancer Project (PCaP) were genotyped using a 1,509 AIM SNP panel. MALD was performed using ADMIXMAP to test for linkage between CaP risk and ancestry estimates at each AIM SNP.RESULTSThe largest increase of African ancestry was observed at marker rs12543473 (P = 0.0011), located on chromosome 8q24.21, and the greatest excess of European ancestry was observed at marker rs10768140 (P = 0.0004) at chromosome 11p13.CONCLUSIONSThe study confirmed the 8q24 risk loci and identified a novel genomic region on 11p13 that is associated with CaP risk. These findings should be replicated in larger AA populations and combined with fine mapping data to further refine the novel 11p13 CaP risk loci. Prostate 74:1–9, 2014. © 2013 Wiley Periodicals, Inc.
Ca2+ clearance mechanisms in cancer cell lines and stromal cells of the prostate
Authors: Wolf Anne , Wennemuth Gunther 
Published: September 2013

AbstractBACKGROUNDThree prostatic cell lines, PC3, LNCaP, and DU 145, are used as established models to study cell signaling in prostate cancer. Recently, stromal cell lines of the prostate, such as P21, were also introduced. Here we investigate a basic and important mechanism of living cells: Ca2+ homeostasis in PC3, DU 145, and P21.METHODSWe examined Ca2+ clearance mechanisms by monitoring the kinetics of recovery from histamine stimulation under conditions which inhibit prospect mechanisms for storing or extrusion of Ca2+ from the cytosol by photometry.RESULTSDespite the fact that in all three cell lines the Ca2+ ATPase of the plasma membrane and the SERCA are most important for Ca2+ homeostasis, inhibition of PMCA in epithelial cells has a greater effect than in stromal cells. Furthermore, the proportion of PMCA and SERCA differs in PC3 and DU145 cells. PMCA is most effective at reaching resting [Ca2+]i in the final recovery stage. In contrast to DU 145 and P21 cells, PC3 are the only cells substantially affected by the inhibition of the mitochondrial uniporter. In all cell lines the role of the sodium calcium exchanger is marginal.CONCLUSIONThese results demonstrate that not only cancer and stromal cell lines show significant differences in the modes and extent of their use of Ca2+ clearance mechanisms, but also the cancer cell lines themselves. Prostate 74:29–40, 2014. © 2013 Wiley Periodicals, Inc.
Nrf2/Maf‐binding‐site‐containing functional Cyp6a2 allele is associated with DDT resistance in Drosophila melanogaster
Authors: Wan Hua , Liu Yan , Li Mei , Zhu Shunyi , Li Xianchun , Pittendrigh Barry R , Qiu Xinghui 
Published: September 2013

AbstractBACKGROUNDIncreased insecticide detoxification mediated by cytochrome P450s is a common mechanism of insecticide resistance. Although Cyp6a2 has been observed to be overexpressed in many 4,4′‐dichlorodiphenyltrichloroethane (DDT)‐resistant strains of Drosophila melanogaster, how Cyp6a2 is regulated and whether its overproduction confers DDT resistance remain elusive.RESULTSMolecular analysis identified five Cyp6a2 alleles (Cyp6a2Canton−S‐1, Cyp6a2Canton−S‐2, Cyp6a291‐C, Cyp6a291‐R and Cyp6a2Wisconsin−WD) from four D. melanogaster strains, notably differing in the presence or absence of an intact Nrf2/Maf (a transcription factor) binding site in the 5′‐promoter core region, a ‘G1410’ frameshift deletion mutation in the heme‐binding region and a long terminal repeat (LTR) of transposable element 17.6 in the 3′‐untranslated region (UTR). Linkage analysis confirmed that DDT resistance was genetically linked to a Nrf2/Maf‐binding‐site‐containing, LTR‐lacking functional allele of Cyp6a2 (Cyp6a291‐R). The qRT‐PCR results showed that overexpression of functional Cyp6a2 was consistently associated with DDT resistance. Luciferase reporter gene assays revealed that an intact Nrf2/Maf binding site in the 5′‐promoter core region enhanced the constitutive transcription of Cyp6a2.CONCLUSIONThe results suggest that the Nrf2/Maf binding‐site‐containing functional Cyp6a2 allele is associated with DDT resistance in the D. melanogaster strains under study. © 2013 Society of Chemical Industry
To Have or Not to Have a Child? Perceived Constraints on Childbearing in a Lowest‐Low Fertility Context
Authors: Wesolowski Katharina 
Published: September 2013

AbstractThe influence of perceived macro‐level constraints on childbearing on women's fertility decision‐making on the micro level was analysed in Stakhanov, a city with a shrinking population in Eastern Ukraine. The perceived macro‐level constraints employed in the study were related to childcare arrangements, value changes regarding family formation, and pollution of the environment and health concerns. To study the influence of those constraints, logistic regression analyses were conducted whereby first‐birth and second‐birth intentions were analysed separately. None of the constraints influenced childless women's first‐birth intentions. Instead, sociodemographic factors such as age and civil status appeared as significant predictors. That none of the constraints influenced childless women's fertility intentions is interpreted to be an indicator of the strong norm of having at least one child in Ukraine.For women with one child, the fact that pollution of the environment and health concerns connected to childbirth were perceived as a constraint on childbearing at the national level was significantly associated with lower second‐birth intentions. Women in Ukraine seem to perceive environmental pollution as a constraint on their fertility, possibly influenced by public discourse related to the health consequences of the Chernobyl nuclear disaster. Moreover, the inhabitants of Stakhanov itself have experienced environmental pollution at close range. Those factors together could explain why environmental pollution and poor health were seen as constraints on childbearing at the national level, and the negative influence these had on second‐birth intentions.It is argued that environmental pollution should be considered a factor influencing fertility decision‐making. Copyright © 2013 John Wiley & Sons, Ltd.