bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of cisterna chyli diameter with MRI in patients with chronic kidney disease
Authors: Albayrak Eda , Ozmen Zafer , Sahin Safak , Demir Osman , Erken Ertugrul 
Published: March 2016

PurposeTo evaluate cisterna chyli (CC) diameter with magnetic resonance imaging (MRI) in patients with chronic kidney disease (CKD).Materials and MethodsThe study included 71 patients with CKD and 68 healthy controls. In both groups, the largest transverse diameter of CC was measured in axial heavily T2‐weighted images using a 1.5T MRI. The diameter of the CC in the CKD patients and control group were compared, and the correlations between the CKD, glomerular filtration rate (GFR), and stage of CKD were investigated. The CC diameters were compared between/among groups with independent sample t‐test or one‐way analysis of variance (ANOVA). A receiver operating characteristic (ROC) curve was constructed for CC diameter to determine the effectiveness of various cutoff points for the presence of CKD. The Pearson correlation coefficient was used to examine correlation between CC diameter and GFR. Multivariate logistic regression models were implemented in order to examine to determine relation among selected variables and study group.ResultsThe average CC diameter was 5.68 ± 2.55 mm in the CKD group, and 3.18 ± 2.24 mm in control group (P < 0.001). The CC diameter showed an increase with more severe stages of the disease (P < 0.001). There was a significant negative correlation between CC diameter and GFR (r –0.447, P < 0.001). Based on multivariate analysis, it was determined that the only factor associated with severity of disease was CC diameter (odds ratio: 1.636, 95% confidence interval: 1.314–2.037, P < 0.0001). Based on ROC analysis, the optimal CC diameter cutoff value for detecting CKD was 4.5 mm, with sensitivity and specificity values of 0.704 and 0.824, respectively.ConclusionCC diameter is observed to be larger in patients with CKD than in the normal population. Additionally, CC diameter increased with more severe stages of CKD. According to our results, CC diameter might be used as an MRI marker to indicate the presence and severity of CKD. J. MAGN. RESON. IMAGING 2016;44:890–896.
Parameter optimization for reproducible cardiac 1H‐MR spectroscopy at 3 Tesla
Authors: de Heer Paul , Bizino Maurice B. , Lamb Hildo J. , Webb Andrew G. 
Published: March 2016

PurposeTo optimize data acquisition parameters in cardiac proton MR spectroscopy, and to evaluate the intra‐ and intersession variability in myocardial triglyceride content.Materials and MethodsData acquisition parameters at 3 Tesla (T) were optimized and reproducibility measured using, in total, 49 healthy subjects. The signal‐to‐noise‐ratio (SNR) and the variance in metabolite amplitude between averages were measured for: (i) global versus local power optimization; (ii) static magnetic field (B0) shimming performed during free‐breathing or within breathholds; (iii) post R‐wave peak measurement times between 50 and 900 ms; (iv) without respiratory compensation, with breathholds and with navigator triggering; and (v) frequency selective excitation, Chemical Shift Selective (CHESS) and Multiply Optimized Insensitive Suppression Train (MOIST) water suppression techniques. Using the optimized parameters intra‐ and intersession myocardial triglyceride content reproducibility was measured. Two cardiac proton spectra were acquired with the same parameters and compared (intrasession reproducibility) after which the subject was removed from the scanner and placed back in the scanner and a third spectrum was acquired which was compared with the first measurement (intersession reproducibility).ResultsLocal power optimization increased SNR on average by 22% compared with global power optimization (P = 0.0002). The average linewidth was not significantly different for pencil beam B0 shimming using free‐breathing or breathholds (19.1 Hz versus 17.5 Hz; P = 0.15). The highest signal stability occurred at a cardiac trigger delay around 240 ms. The mean amplitude variation was significantly lower for breathholds versus free‐breathing (P = 0.03) and for navigator triggering versus free‐breathing (P = 0.03) as well as for navigator triggering versus breathhold (P = 0.02). The mean residual water signal using CHESS (1.1%, P = 0.01) or MOIST (0.7%, P = 0.01) water suppression was significantly lower than using frequency selective excitation water suppression (7.0%). Using the optimized parameters an intrasession limits of agreement of the myocardial triglyceride content of ‐0.11% to +0.04%, and an intersession of ‐0.15% to +0.9%, were achieved. The coefficient of variation was 5% for the intrasession reproducibility and 6.5% for the intersession reproducibility.ConclusionUsing approaches designed to optimize SNR and minimize the variation in inter‐average signal intensities and frequencies/phases, a protocol was developed to perform cardiac MR spectroscopy on a clinical 3T system with high reproducibility. J. Magn. Reson. Imaging 2016;44:1151–1158.
Impact of trophic state on the distribution of intact polar lipids in surface waters of lakes
Authors: Bale Nicole J. , Hopmans Ellen C. , Schoon Petra L. , de Kluijver Anna , Downing John A. , Middelburg Jack J. , Sinninghe Damsté Jaap S. , Schouten Stefan 
Published: March 2016

AbstractWe characterized the intact polar lipid (IPL) composition in the surface waters of 22 lakes from Minnesota and Iowa, ranging in trophic state between eutrophic and oligo‐mesotrophic, to investigate the impact of trophic state on IPL composition. A high diversity of IPL classes was detected. Most IPL classes were detected in all lakes, but the eutrophic lakes contained a significantly higher relative abundance of lyso‐phosphatidylcholine (PC) than the oligo‐mesotrophic lakes, which in turn were characterized by significantly higher relative abundance of hydroxymethyltrimethyl‐alanine/trimethyl‐homoserine (DGTA/DGTS) betaines, ornithine lipids and the recently discovered trimethyl ornithine (TMO) lipids. The higher relative abundance of ornithines and TMOs may relate to a higher contribution of heterotrophic bacteria relative to phytoplankton while the higher abundance of the DGTA/DGTS betaines may relate to substitution by microorganisms of these non‐P lipids for PC under P‐stress, as has been observed in other environments. We also detected a variety of heterocyst glycolipids (HGs) derived from N2‐fixing heterocystous Cyanobacteria in all lakes, suggesting the presence of these Cyanobacteria in the full range of trophic conditions. Correlation of HG abundance with environmental data showed that high productivity lakes have high HG abundances, while other distributional differences in HGs, which did not correlate with environmental parameters, are likely due to differences in species composition. We conclude that the significant differences in IPL composition between the eutrophic and oligo‐mesotrophic lakes are either due to adaptation of the membrane composition to nutrient conditions or due to general divergences in microbial composition under the different conditions.
Carotenoid accumulation in copepods is related to lipid metabolism and reproduction rather than to UV‐protection
Authors: Schneider Tobias , Grosbois Guillaume , Vincent Warwick F. , Rautio Milla 
Published: March 2016

AbstractAccumulation of carotenoid pigments in copepods has often been described as a plastic adaptation providing photoprotection against ultraviolet radiation (UVR). However, reports of seasonal carotenoid maxima in winter, when UVR is low, challenge the proposed driving role of UVR. Therefore, we here evaluate the mechanistic connection between UVR and the seasonal pattern of copepod carotenoid pigmentation. We assessed the carotenoids, fatty acid content and reproduction of Leptodiaptomus minutus along with UVR exposure, water temperature, phytoplankton pigments, and fish predation in a boreal lake during 18 months covering two winter seasons. The predominant carotenoid astaxanthin occurred in free form as well as esterified with fatty acids. Mono‐ and diesters accounted for 62–93% of total astaxanthin and varied seasonally in close correlation with fatty acids. The seasonal variability in total astaxanthin content of the copepods was characterized by net accumulation in late fall of up to 0.034 μg (mg dry mass)−1 d−1, which led to the mid‐winter maximum of 3.89 ± 0.31 μg mg−1. The two periods of net loss (−0.018 μg mg−1 d−1 and −0.021 μg mg−1 d−1) coincided with peaks of egg production in spring and summer leading to minimum astaxanthin content (0.86 ± 0.03 μg mg−1) in fall. This period was also characterized by the highest predation pressure by young‐of‐the‐year fish. The results suggest that accumulation of astaxanthin in copepods is strongly related to lipid metabolism but not to UVR‐photoprotection, and that seasonal changes of fatty acids and carotenoids are related to the reproduction cycle.
Carbon isotope fractionation in phytoplankton as a potential proxy for pH rather than for [CO2(aq)]: Observations from a carbonate lake
Authors: Wang Shilu , Yeager Kevin M. , Lu Weiqi 
Published: March 2016

AbstractThe method of reconstructing paleoatmospheric CO2 levels using carbon isotope signatures of organic matter buried in sediments has been questioned due to the dubious foundation that carbon isotope fractionation during phytoplankton photosynthesis (εp) is controlled primarily by aquatic CO2 concentration ([CO2(aq)]). Consequently, what carbon isotope data from bulk sedimentary organic matter reflects is a puzzle. In this study, we determined the carbon isotope compositions of dissolved inorganic carbon and particulate organic carbon in a lake located in a carbonate area. Partial correlation analysis was employed to distinguish between direct and indirect factors in controlling εp. The results show that εp is more closely, and more steadily related with pH than with [CO2(aq)], which is in accordance with recent advances in our understanding of the physiology of carbon utilization by phytoplankton for CO2 and
. Therefore, we propose that carbon isotope fractionation in phytoplankton is more suitable as a proxy of pH than of [CO2(aq)]. One advantage of this amendment is that information on
, the main species of carbon uptake by phytoplankton, is likewise included. In the future, culture experiments aiming at revealing the relationship between pH and cellular carbon isotope signatures is necessary to construct a new isotope fractionation formula to couple the different effects of CO2 and
, which is of critical importance to improve the understanding of carbon isotope fractionation, and to more precisely model pH and CO2.
Reply to comment: Prey perception in feeding‐current feeding copepods
Authors: Kiørboe Thomas , Gonçalves Rodrigo J. , Couespel Damien , van Someren Gréve Hans , Saiz Enric , Tiselius Peter 
Published: March 2016

AbstractWe reply to the comments of Paffenhöfer and Jiang () who argues that remote chemical prey perception is necessary for feeding‐current feeding copepods to fulfill their nutritional requirements in a dilute ocean, that remote chemical prey detection may only be observed at very low prey concentrations, and that chemical prey perception is feasible if prey cells release dissolved organic material in short‐lasting but intense bursts. We demonstrate that mechanoreception at a very short range is sufficient to sustain a living, even in a dilute ocean. Further, if chemoreception requires that prey cells have short intense leakage burst, only a very small fraction of prey cells would be available to the copepod at any instance in time and, thus would be inefficient at low prey concentration. Finally, we report a few new observations of prey capture in two species of copepods, Temora longicornis and Centropages hamatus, offered a 45‐μm sized dinoflagellate at very low concentration. The observed short prey detection distances, up to a few prey cell radii, are consistent with mechanoreception and we argue briefly that near‐field mechanoreception is the most likely and common prey perception mechanism in calanoid copepods.
Comment: On phytoplankton perception by calanoid copepods
Authors: Paffenhöfer Gustav‐Adolf , Jiang Houshuo 
Published: March 2016

AbstractThree publications recently reported that calanoid copepods, feeding on phytoplankton cells by using a feeding current, perceived such cells by mechanoperception. There was no evidence of remote chemically‐mediated perception of those cells. These observations differ from earlier findings that feeding‐current producing calanoids are able to detect phytoplankton cells by chemoperception at a distance from their particle‐collecting setae of their cephalic appendages. The results on mechanoperception and the earlier published data on chemoperception will be presented and discussed. In addition, the concentration of chemicals within the phycosphere of food cells will be re‐examined. We conclude that chemoperception of phytoplankton cells by calanoid copepods in a feeding current is feasible.
Accelerated phase contrast flow imaging with direct complex difference reconstruction
Authors: Sun Aiqi , Zhao Bo , Ma Ke , Zhou Zechen , He Le , Li Rui , Yuan Chun 
Published: March 2016

PurposeTo propose and evaluate a new model‐based reconstruction method for highly accelerated phase‐contrast magnetic resonance imaging (PC‐MRI) with sparse sampling.Theory and MethodsThis work presents a new constrained reconstruction method based on low‐rank and sparsity constraints to accelerate PC‐MRI. More specifically, we formulate the image reconstruction problem into separate reconstructions of flow‐reference image sequence and complex differences. We then utilize the joint partial separability and sparsity constraints to enable high quality reconstruction from highly undersampled
‐space data. We further integrate the proposed method with ESPIRiT based parallel imaging model to effectively handle multichannel acquisition.ResultsThe proposed method was evaluated with in vivo data acquired from both 2D and 3D PC flow imaging experiments, and compared with several state‐of‐the‐art methods. Experimental results demonstrate that the proposed method leads to more accurate velocity reconstruction from highly undersampled
‐space data, and particularly superior capability of capturing the peak velocity of blood flow. In terms of flow visualization, blood flow patterns obtained from the proposed reconstruction also exhibit better agreement with those obtained from the fully sampled reference.ConclusionThe proposed method achieves improved accuracy over several state‐of‐the‐art methods for velocity reconstruction with highly accelerated
‐space data. Magn Reson Med 77:1036–1048, 2017. © 2016 International Society for Magnetic Resonance in Medicine
Sequential combination of k‐t principle component analysis (PCA) and partial parallel imaging: k‐t PCA GROWL
Authors: Qi Haikun , Huang Feng , Zhou Hongmei , Chen Huijun 
Published: March 2016

Purposek‐t principle component analysis (k‐t PCA) is a distinguished method for high spatiotemporal resolution dynamic MRI. To further improve the accuracy of k‐t PCA, a combination with partial parallel imaging (PPI), k‐t PCA/SENSE, has been tested. However, k‐t PCA/SENSE suffers from long reconstruction time and limited improvement. This study aims to improve the combination of k‐t PCA and PPI on both reconstruction speed and accuracy.MethodsA sequential combination scheme called k‐t PCA GROWL (GRAPPA operator for wider readout line) was proposed. The GRAPPA operator was performed before k‐t PCA to extend each readout line into a wider band, which improved the condition of the encoding matrix in the following k‐t PCA reconstruction. k‐t PCA GROWL was tested and compared with k‐t PCA and k‐t PCA/SENSE on cardiac imaging.Resultsk‐t PCA GROWL consistently resulted in better image quality compared with k‐t PCA/SENSE at high acceleration factors for both retrospectively and prospectively undersampled cardiac imaging, with a much lower computation cost. The improvement in image quality became greater with the increase of acceleration factor.ConclusionBy sequentially combining the GRAPPA operator and k‐t PCA, the proposed k‐t PCA GROWL method outperformed k‐t PCA/SENSE in both reconstruction speed and accuracy, suggesting that k‐t PCA GROWL is a better combination scheme than k‐t PCA/SENSE. Magn Reson Med 77:1058–1067, 2017. © 2016 International Society for Magnetic Resonance in Medicine
Growth hormone receptor expression in human gluteal versus abdominal subcutaneous adipose tissue: Association with body shape
Authors: Karastergiou Kalypso , Bredella Miriam A. , Lee Mi‐Jeong , Smith Steven R. , Fried Susan K. , Miller Karen K. 
Published: March 2016

ObjectiveGrowth hormone (GH) administration reduces abdominal, but not lower body, fat mass. To gain insight into the underlying mechanisms, this study examined the expression of the GH receptor (GHR) and some of its targets in abdominal and gluteal adipose tissue.MethodsGHR and GH targets in the lipolytic pathway were assessed (quantitative PCR/Western blotting) in adipose aspirates from premenopausal women [n = 15, age 26.9 ± 6.1 years, body mass index (BMI) 28.0 ± 6.8 kg/m2] and men (n = 28, age 29.2 ± 7.0 years, BMI 26.9 ± 3.7 kg/m2).ResultsGHR mRNA expression was lower in the gluteal depot when compared with the abdominal depot (P = 0.01). Abdominal GHR correlated negatively with age and BMI, whereas gluteal GHR was associated with lower waist‐to‐hip ratio (WHR), that is, pear shape. In both sites, GHR mRNA correlated strongly with genes important for the regulation of lipolysis: adipose tissue triglyceride lipase (ATGL), hormone‐sensitive lipase, perilipin, and CIDEA (all P < 0.001), independently of BMI, WHR, age, and sex. GHR protein was lower in the gluteal fat when compared with the abdominal fat (P = 0.03) and correlated with ATGL protein in the gluteal depot (P < 0.001).ConclusionsGHR levels correlate with levels of lipases and lipid droplet‐associated proteins crucial for lipolysis. Thus, higher GHR expression in the abdominal depot when compared with the gluteal depot may underlie the in vivo effect of GH to specifically reduce abdominal adipose tissue mass.
Maternal caffeine intake during pregnancy, early growth, and body fat distribution at school age
Authors: Voerman Ellis , Jaddoe Vincent W.V. , Gishti Olta , Hofman Albert , Franco Oscar H. , Gaillard Romy 
Published: March 2016

ObjectiveThe associations of maternal caffeine intake during pregnancy with offspring growth patterns and body fat and insulin levels at school age were examined.MethodsIn a population‐based birth cohort among 7,857 mothers and their children, maternal caffeine intake during pregnancy was assessed by questionnaires. Growth characteristics were measured from birth onward. At 6 years, body fat and insulin levels were measured.ResultsCompared to children whose mothers consumed <2 units of caffeine per day during pregnancy (1 unit of caffeine is equivalent to 1 cup of coffee (90 mg caffeine)), those whose mothers consumed ≥6 units of caffeine per day tended to have a lower weight at birth, higher weight gain from birth to 6 years, and higher body mass index from 6 months to 6 years. Both children whose mothers consumed 4‐5.9 and ≥6 units of caffeine per day during pregnancy tended to have a higher childhood body mass index and total body fat mass. Only children whose mothers consumed ≥6 units of caffeine per day had a higher android/gynoid fat mass ratio.ConclusionsThese results suggest that high levels of maternal caffeine intake during pregnancy are associated with adverse offspring growth patterns and childhood body fat distribution.
Cost‐Effectiveness of High‐Dose Edoxaban Compared with Adjusted‐Dose Warfarin for Stroke Prevention in Non–Valvular Atrial Fibrillation Patients
Authors: Nguyen Elaine , Egri Florence , Mearns Elizabeth S. , White Charles M. , Coleman Craig I. 
Published: March 2016

ObjectiveTo estimate the quality‐adjusted life‐years (QALYs), costs, and cost‐effectiveness of high‐dose edoxaban compared with adjusted‐dose warfarin in patients at risk for stroke who have nonvalvular atrial fibrillation (NVAF) and a creatinine clearance (Clcr) of 15–95 ml/minute.MethodsA Markov model was created to compare the cost‐effectiveness of high‐dose edoxaban and adjusted‐dose warfarin in patients with a Clcrof 15–95 ml/minute. The model was performed from a U.S. societal perspective and assumed patients initiated therapy at 70 years of age, had a meanCHADS2(congestive heart failure, hypertension, age 75 or older, diabetes, stroke) score of 3, and no contraindications to anticoagulation. The model assumed a cycle length of 1 month and a lifetime horizon (maximum of 30 years/360 cycles). Data sources included renal subgroup analysis of the Effective Anticoagulation with Factor Xa Next Generation in Atrial Fibrillation (ENGAGE‐AF) trial and other published studies. Outcomes included lifetime costs (2014US$),QALYs, and incremental cost‐effectiveness ratios. The robustness of the model's conclusions was tested using one‐way and 10,000‐iteration probabilistic sensitivity analysis (PSA).ResultsPatients treated with high‐dose edoxaban lived an average of 10.50QALYs at a lifetime treatment cost of $99,833 compared with 10.11QALYs and $123,516 for those treated with adjusted‐dose warfarin. The model's conclusions were found to be robust upon one‐way sensitivity analyses.PSAsuggested high‐dose edoxaban was economically dominant compared with adjusted‐dose warfarin in more than 99% of the 10,000 iterations run.ConclusionsHigh‐dose edoxaban appears to be an economically dominant strategy when compared with adjusted‐dose warfarin for the prevention of stroke inNVAFpatients with a Clcrof 15–95 ml/minute and an appreciable risk of stroke.
Thermosensitive behavior of amphiphilic triblock copolymers based on poly(acrylic acid) and poly(propylene oxide)
Authors: Pottier Christophe , Morandi Gaëlle , Rihouey Christophe , Dulong Virginie , Picton Luc , Le Cerf Didier 
Published: March 2016

ABSTRACTSelf‐association in aqueous solution of amphiphilic poly(acrylic acid)‐b‐poly(propylene oxide)‐b‐poly(acrylic acid) (PAA‐b‐PPO‐b‐PAA) copolymers having various outer PAA block lengths are presented. These copolymers show two thermosensitive behaviors. The first one, due to hydrogen bonds between PAA and PPO resulting in large aggregates, was observed by visible spectroscopy. The second one, due to the association of PPO middle block into aggregates, was evidenced by dynamic light scattering and pyrene fluorescence. These critical temperatures both depend on the ionization and the length of PAA blocks. The characterization of the aggregates above the critical aggregation concentration by fluorescence quenching experiments showed a very low aggregation number corresponding to dimers or trimers association depending on the conditions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1507–1514
Concise Review: Advances in Generating Hepatocytes from Pluripotent Stem Cells for Translational Medicine
Authors: Szkolnicka Dagmara , Hay David C. 
Published: March 2016

Abstract
The liver is one of the major organs in the human body. Severe or prolonged exposure of the liver to different factors may cause life-threatening disease, which necessitates donor organ transplantation. While orthotopic liver transplantation can be used to effectively treat liver failure, it is an invasive procedure, which is severely limited by organ donation. Therefore, alternative sources of liver support have been proposed and studied. This includes the use of pluripotent stem cell-derived hepatocytes as a renewable source of cells for therapy. In addition to cell-based therapies, in vitro engineered liver tissue provides powerful models for human drug discovery and disease modeling. This review focuses on the generation of hepatocyte-like cells from pluripotent stem cells and their application in translational medicine.