bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accuracy, repeatability, and interplatform reproducibility of T1 quantification methods used for DCE‐MRI: Results from a multicenter phantom study
Authors: Bane Octavia , Hectors Stefanie J. , Wagner Mathilde , Arlinghaus Lori L. , Aryal Madhava P. , Cao Yue , Chenevert Thomas L. , Fennessy Fiona , Huang Wei , Hylton Nola M. , Kalpathy‐Cramer Jayashree , Keenan Kathryn E. , Malyarenko Dariya I. , Mulkern Robert V. , Newitt David C. , Russek Stephen E. , Stupic Karl F. , Tudorica Alina , Wilmes Lisa J. , Yankeelov Thomas E. , Yen Yi‐Fei , Boss Michael A. , Taouli Bachir 
Published: September 2017

PurposeTo determine the in vitro accuracy, test‐retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast‐enhanced MRI at 1.5 and 3 T.MethodsA T1 phantom with 14 samples was imaged at eight centers with a common inversion‐recovery spin‐echo (IR‐SE) protocol and a variable flip angle (VFA) protocol using seven flip angles, as well as site‐specific protocols (VFA with different flip angles, variable repetition time, proton density, and Look‐Locker inversion recovery). Factors influencing the accuracy (deviation from reference NMR T1 measurements) and repeatability were assessed using general linear mixed models. Interplatform reproducibility was assessed using coefficients of variation.ResultsFor the common IR‐SE protocol, accuracy (median error across platforms = 1.4–5.5%) was influenced predominantly by T1 sample (P < 10−6), whereas test‐retest repeatability (median error = 0.2–8.3%) was influenced by the scanner (P < 10−6). For the common VFA protocol, accuracy (median error = 5.7–32.2%) was influenced by field strength (P = 0.006), whereas repeatability (median error = 0.7–25.8%) was influenced by the scanner (P < 0.0001). Interplatform reproducibility with the common VFA was lower at 3 T than 1.5 T (P = 0.004), and lower than that of the common IR‐SE protocol (coefficient of variation 1.5T: VFA/IR‐SE = 11.13%/8.21%, P = 0.028; 3 T: VFA/IR‐SE = 22.87%/5.46%, P = 0.001). Among the site‐specific protocols, Look‐Locker inversion recovery and VFA (2–3 flip angles) protocols showed the best accuracy and repeatability (errors < 15%).ConclusionsThe VFA protocols with 2 to 3 flip angles optimized for different applications achieved acceptable balance of extensive spatial coverage, accuracy, and repeatability in T1 quantification (errors < 15%). Further optimization in terms of flip‐angle choice for each tissue application, and the use of B1 correction, are needed to improve the robustness of VFA protocols for T1 mapping. Magn Reson Med 79:2564–2575, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Simultaneous acquisition of perfusion image and dynamic MR angiography using time‐encoded pseudo‐continuous ASL
Authors: Suzuki Yuriko , Helle Michael , Koken Peter , Van Cauteren Marc , van Osch Matthias J. P. 
Published: September 2017

PurposeBoth dynamic magnetic resonance angiography (4D‐MRA) and perfusion imaging can be acquired by using arterial spin labeling (ASL). While 4D‐MRA highlights large vessel pathology, such as stenosis or collateral blood flow patterns, perfusion imaging provides information on the microvascular status. Therefore, a complete picture of the cerebral hemodynamic condition could be obtained by combining the two techniques. Here, we propose a novel technique for simultaneous acquisition of 4D‐MRA and perfusion imaging using time‐encoded pseudo‐continuous arterial spin labeling.MethodsThe time‐encoded pseudo‐continuous arterial spin labeling module consisted of a first subbolus that was optimized for perfusion imaging by using a labeling duration of 1800 ms, whereas the other six subboli of 130 ms were used for encoding the passage of the labeled spins through the arterial system for 4D‐MRA acquisition. After the entire labeling module, a multishot 3D turbo‐field echo‐planar‐imaging readout was executed for the 4D‐MRA acquisition, immediately followed by a single‐shot, multislice echo‐planar‐imaging readout for perfusion imaging. The optimal excitation flip angle for the 3D turbo‐field echo‐planar‐imaging readout was investigated by evaluating the image quality of the 4D‐MRA and perfusion images as well as the accuracy of the estimated cerebral blood flow values.ResultsWhen using 36 excitation radiofrequency pulses with flip angles of 5 or 7.5°, the saturation effects of the 3D turbo‐field echo‐planar‐imaging readout on the perfusion images were relatively moderate and after correction, there were no statistically significant differences between the obtained cerebral blood flow values and those from traditional time‐encoded pseudo‐continuous arterial spin labeling.ConclusionsThis study demonstrated that simultaneous acquisition of 4D‐MRA and perfusion images can be achieved by using time‐encoded pseudo‐continuous arterial spin labeling. Magn Reson Med 79:2676–2684, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
An improved model for prostate diffusion incorporating the results of Monte Carlo simulations of diffusion in the cellular compartment
Authors: Gilani Nima , Malcolm Paul , Johnson Glyn 
Published: September 2017

The purpose of this work was to refine a previously published model of prostate diffusion by incorporating improved estimates of cellular diffusivity obtained by Monte Carlo simulation.Stromal and epithelial cell size and intracellular volume fraction in different grades of cancer were determined from histological images. Diffusion in different mixtures of cells, corresponding to different tumor grades, was simulated and cellular apparent diffusion coefficient and kurtosis values determined. These values were incorporated into the previously published model of prostate diffusion and model predictions compared with values found in the literature.Stromal cell radius and intracellular volume fraction were 3.74 ± 0.96 μm and 13 ± 3% respectively in normal peripheral zone (PZ), and were similar in all grades of cancer. Epithelial cell radius and intracellular volume fraction were 3.40 ± 0.15 μm and 45 ± 5% respectively in normal PZ, rising to 4.75 ± 0.20 μm and 70 ± 8% in high grade cancer. Cellular apparent diffusion coefficient and kurtosis were 1.02 μm2 ms−1 and 0.58 respectively in normal PZ, and 0.61 μm2 ms−1 and 1.15 in high grade cancer (variation in simulation values are less than 0.1%). Agreement between model predictions and measurements were good, with a mean square error of 0.22 μm2 ms−1.Incorporation of cellular diffusion coefficient and kurtosis values obtained by Monte Carlo simulation into a model of prostate diffusion gives good agreement with published results.
1H–MRS processing parameters affect metabolite quantification: The urgent need for uniform and transparent standardization
Authors: Bhogal Alex A. , Schür Remmelt R. , Houtepen Lotte C. , van de Bank Bart , Boer Vincent O. , Marsman Anouk , Barker Peter B. , Scheenen Tom W.J. , Wijnen Jannie P. , Vinkers Christiaan H. , Klomp Dennis W.J. 
Published: September 2017

Proton magnetic resonance spectroscopy (1H–MRS) can be used to quantify in vivo metabolite levels, such as lactate, γ‐aminobutyric acid (GABA) and glutamate (Glu). However, there are considerable analysis choices which can alter the accuracy or precision of 1H–MRS metabolite quantification. It is currently unknown to what extent variations in the analysis pipeline used to quantify 1H–MRS data affect outcomes. The purpose of this study was to evaluate whether the quantification of identical 1H–MRS scans across independent and experienced research groups would yield comparable results. We investigated the influence of model parameters and spectral quantification software on fitted metabolite concentration values. Sixty spectra in 30 individuals (repeated measures) were acquired using a 7‐T MRI scanner. Data were processed by four independent research groups with the freedom to choose their own individualized and optimal parameter settings using LCModel software. Data were processed a second time in one group using an independent software package (NMRWizard) for an additional comparison with a different post‐processing platform. Correlations across research groups of the ratio between the highest and, arguably, the most relevant resonances for neurotransmission [N‐acetyl aspartate (NAA), N‐acetyl aspartyl glutamate (NAAG) and Glu] over the total creatine [creatine (Cr) + phosphocreatine (PCr)] concentration, using Pearson's product–moment correlation coefficient (r), were calculated. Mean inter‐group correlations using LCModel software were 0.87, 0.88 and 0.77 for NAA/Cr + PCr, NAA + NAAG/Cr + PCr and Glu/Cr + PCr, respectively. The mean correlations when comparing NMRWizard results with LCModel fitting results at University Medical Center Utrecht (UMCU) were 0.87, 0.89 and 0.71 for NAA/Cr + PCr, NAA + NAAG/Cr + PCr and Glu/Cr + PCr, respectively. Metabolite quantification using identical 1H–MRS data was influenced by processing parameters, basis sets and software choice. Locally preferred processing choices affected metabolite quantification, even when using identical software. Our results reinforce the notion that standard practices should be established to regularize outcomes of 1H–MRS studies, and that basis sets used for processing should be made available to the scientific community.
Secure and efficient verification for data aggregation in wireless sensor networks
Authors: Merad Boudia Omar Rafik , Senouci Sidi Mohammed , Feham Mohammed 
Published: September 2017

SummaryThe Internet of Things (IoT) concept is, and will be, one of the most interesting topics in the field of Information and Communications Technology. Covering a wide range of applications, wireless sensor networks (WSNs) can play an important role in IoT by seamless integration among thousands of sensors. The benefits of using WSN in IoT include the integrity, scalability, robustness, and easiness in deployment. In WSNs, data aggregation is a famous technique, which, on one hand, plays an essential role in energy preservation and, on the other hand, makes the network prone to different kinds of attacks. The detection of false data injection and impersonation attacks is one of the major concerns in WSNs. In order to verify the data, there is either the end‐to‐end approach or the hop‐by‐hop approach. In the former, the detection of these attacks can only be performed at sink node, i.e., after reception of aggregate, a detection that is inefficient and leads to a significant loss of legitimate data. In this paper, we propose a scheme that provides the end‐to‐end privacy and allows early detection of the attack through a hop‐by‐hop verification, thus reducing the need to rely entirely on sink node for verification. Based on an enhanced version of TinyECC, the solution is implemented on MicaZ and TelosB motes. Through simulation and experimental results, we show the applicability of the scheme for WSNs.
Polyurethanes with separately tunable biodegradation behavior and mechanical properties for tissue engineering
Authors: Moghanizadeh‐Ashkezari Mojgan , Shokrollahi Parvin , Zandi Mojgan , Shokrolahi Fatemeh 
Published: September 2017

Two series (random and block) poly(glycolide‐co‐ε‐caprolactone) macrodiols with various glycolide to ε‐caprolactone ratios (50/50 and 30/70, R‐PG50C, R‐PG30C, B‐PG50C, and B‐PG30C) were synthesized. Next, segmented polyurethanes (PUs) were synthesized based on the synthesized macrodiols, 1,6‐hexamethylene diisocyanate and 1,4‐butanediol (PU‐R30, PU‐R50, PU‐B30, and PU‐B50). Effect of glycolide (G) and ε‐caprolactone (C) monomers arrangement (random or block) on the PUs properties were investigated via FTIR, 1H NMR, DSC, TGA, DMA, SEM, and mechanical tests. All PUs illustrated Tg (−33°C to −48°C) and Tm (102°C to 139°C) corresponding to the soft and the hard segments, respectively. Polymers based on block macrodiols also showed Tm related to the soft segments. While PUs underwent a two‐step thermal degradation, the PUs based on block macrodiols indicated higher degradation temperature. Dynamic mechanical analysis results evidenced development of a well‐defined microphase separated structure in PU‐R30. Contact angle (about 70°‐80°) and water uptake (around 20% after 24 hours) of the PU films are close to those suitable for tissue engineering materials. The PU based on R‐PG30C (PU‐R30) exhibited the highest tensile strength (2.87 MPa) followed by PU‐B50 and PU‐R50. Over a 63‐day in vitro degradation study in phosphate buffered saline, the PUs showed variable weight loss (up to 40%) depending on their soft segments composition and arrangement. Also, the PUs showed no cytotoxicity. Thus, these PUs with tunable biodegradation rate and mechanical properties are suitable candidates for tissue engineering.
Cardioprotective Effects of Pomegranate (Punica granatum) Juice in Patients with Ischemic Heart Disease
Authors: Razani Zahra , Dastani Mostafa , Kazerani Hamid Reza 
Published: September 2017

Ischemic heart disease is the leading cause of mortality worldwide. The purpose of this study was to evaluate the cardioprotective effects of pomegranate juice in patients with ischemic heart disease. One hundred patients, diagnosed with unstable angina or myocardial infarction, were randomly assigned to the test and the control groups (n = 50, each). During 5 days of hospitalization, in addition to the conventional medical therapies, the test groups received 220 mL pomegranate juice, daily. During the hospitalization period, the blood pressure, heart rate, as well as the intensity, occurrence, and duration of the angina were evaluated on a regular basis. At the end of the hospitalization period, the serum levels of malondialdehyde, interleukin‐6, and tumor necrosis factor alpha were measured in all patients. The levels of serum troponin and high‐sensitive C‐reactive protein levels were also assayed in patients diagnosed with myocardial infarction. Pomegranate juice caused significant reductions in the intensity, occurrence, and duration of angina pectoris in patients with unstable angina. Consistently, the test patients had significantly lower levels of serum troponin and malondialdehyde. Other studied parameters did not change significantly. The results of this study suggest protective effects of pomegranate juice against myocardial ischemia and reperfusion injury. Copyright © 2017 John Wiley & Sons, Ltd.
Hyphenation of proton transfer reaction mass spectrometry with thermal analysis for monitoring the thermal degradation of retinyl acetate
Authors: Peinado Irene , Mason Marco , Biasioli Franco , Scampicchio Matteo 
Published: September 2017

RationaleThe processing of retinyl acetate, a vitamin and biomarker, at high temperatures causes significant decomposition of the compound and thus loss of its activity. The rate of mass loss can be conveniently studied by thermogravimetry (TG). However, this technique generally fails to reveal which compounds have evolved from the compound. In this work we propose a new hyphenation approach to continuously monitor the thermal decomposition of retinyl acetate and follow the evolution of specific volatile organic compounds (VOCs).MethodsThermal degradation of retinyl acetate was followed by TG coupled to a direct injection mass spectrometer based on proton transfer reaction mass spectrometry (PTR‐MS) to follow continuously the thermal decomposition of retinyl acetate. The results were also compared with those obtained by a second evolved gas analysis system based on the coupling of TG with FTIR.ResultsThe TG results showed two main mass losses, at 180°C and 350°C. When the PTR‐MS instrument was connected to the outlet of the TG instrument, specific fragment ions (m/z 43, 61, 75, 85 and 97) showed characteristic evolution profiles. The first mass loss was mainly associated with the release of acetic acid (m/z 43 and 61), whereas the second mass loss was connected with the degradation of the molecule backbone (m/z 43, 61, 75, 85 and 97). These results were substantially correlated with those achieved by TG coupled with FTIR, although PTR‐MS showed superior performance in terms of the qualitative identification of specific fragments and better sensitivity toward complex organic VOCs.ConclusionsThe proposed TG‐PTR‐MS technique shows a great potential for following in real time the thermal degradation of ingredients such as retinyl acetate and identifying compounds evolved at specific temperatures.
High‐performance liquid chromatography/high‐resolution mass spectrometry for the characterization of transformation products of ionic liquids
Authors: Fabbri Debora , Calza Paola , Noè Giorgio , Santoro Valentina , Medana Claudio 
Published: September 2017

RationaleIonic liquids (ILs) are a subject of active research in the field of alternative solvents. We studied the behaviour of a piperidine IL, 1‐butyl‐1‐methylpiperidinium tetrafluoroborate (BMPA), through the elucidation of its transformation products (TPs) in water.MethodsThe transformation pathways of BMPA were investigated using high‐performance liquid chromatography (HPLC) combined with a hybrid LTQ‐Orbitrap instrument on the basis of mass defect filtering. TPs of BMPA were identified by fragmentation patterns and accurate mass measurements.ResultsThe separation and identification of 32 TPs was achieved. BMPA can be oxidized at different positions in the alkyl chains. The ultimate products corresponds to N‐methyl‐piperidinium and some byproducts involving ring‐opening. Tests of acute toxicity, evaluated with Vibrio Fischeri bacteria, show that BMPA transformation proceeds through the formation of slightly harmful compounds.ConclusionsResults showed that the main transformation pathways of BMPA were alkyl chain hydroxylation/shortening and de‐alkylation, and that HPLC/LTQ‐Orbitrap can serve as an important analytical platform to gather the unknown TPs of ILs.
A ToF‐SIMS investigation on correlation between grinding environments and sphalerite surface chemistry: implications for mineral selectivity in flotation
Authors: Xia Liuyin , Hart Brian , Chen Zhe , Furlotte Mark , Gingras Gary , Laflamme Patrick 
Published: September 2017

AbstractChanges in mineral surface properties during grinding play a key role in flotation performance. Time of flight secondary mass spectrometry (ToF‐SIMS) surface chemical analytical studies have shown that flotation separation of sphalerite from chalcopyrite is significantly affected by the oxidation of metal species on the surface of sphalerite. The intensity of iron oxyhydroxyl species on the surface of sphalerite has a positive correlation with poor recovery of sphalerite. Given the link between the presence of oxide species on the surface of sphalerite and a lower recovery during copper flotation, a laboratory study was initiated to evaluate the potential for sphalerite surface oxidation control and improving recovery through grinding. For the investigation, a ball mill that allowed for monitoring pulp chemistry during grinding was utilized to study the impact of grinding conditions on selective flotation of sphalerite. ToF‐SIMS was used to identify and measure the variability in sphalerite surface species as a result of the different test parameters. Variable mill parameters include two types of grinding media, aeration conditions, addition of FeSO4, and altering the pyrite content in the feed ore. ToF‐SIMS analyses of mill discharge samples identified higher intensities of iron oxyhydroxyl species on sphalerite surface subsequent to grinding with mild steel balls, in condition of aeration, use of FeSO4, and by increasing the pyrite content of the feed ore. The higher adsorption of iron oxyhydroxyl species on the surface of sphalerite should be consistent with the lower recovery. To verify this, bench‐scale flotation tests in the presence and absence of FeSO4 were performed; results correlated iron oxyhydroxyl species with the poor sphalerite recovery. Copyright © 2017 John Wiley & Sons, Ltd.
Visible Light Driven Coupling of 2‐aminopyridines and α‐Keto Vinyl Azides for the Synthesis of Imidazo[1, 2‐a]pyridines and Their Cytotoxicity
Authors: Adiyala Praveen Reddy , Sastry Kasinathuni Naga Visweswara , Kovvuri Jeshma , Nagarajan Apoorva , Reddy Velma Ganga , Sayeed Ibrahim Bin , Nayak Vedinthe Lakshma , Maurya Ram Awatar , Kamal Ahmed 
Published: September 2017

Abstractα‐Keto vinyl azides and 2‐aminopyridines were coupled to yield 1‐aryl‐N‐(2‐arylimidazo[1, 2‐a]pyridin‐3‐yl)methanimines in the presence of visible light using Ru(bpy)3Cl2.6H2O as a photocatalyst. This synthetic protocol allows the formation of 3 new C−N bonds in the overall transformation at ambient temperature. It is applicable to a wide range of vinyl azides and 2‐aminopyridines providing a straightforward access to a variety of highly functionalized imidazo[1, 2‐a]pyridines in high yields. The synthesized imidazo[1, 2‐a]pyridines were evaluated for their cytotoxic activity against a set of four selected human cancer cell lines i.e, A549 (lung cancer), DU‐145 (prostate cancer), MCF‐7 (breast cancer) and Hela (cervical cancer). Many compounds of the series (4 e, 4 g, 4 i, 4 j and 4 u) exhibited promising cytotoxicity in these cancer cell lines.
Dangers on the road: A longitudinal examination of passenger‐initiated violence against bus drivers
Authors: Zhou Biru , Boyer Richard , Guay Stéphane 
Published: September 2017

AbstractThis study examined the impact of workplace violence against 109 bus drivers over a 1‐year span. Workplace violence is related to both psychological and work‐related consequences. Our findings showed that bus drivers experienced a wide range of violence at work and the psychological consequences were devastating: Half of the participants met the diagnostic criteria for acute stress disorder within the first month following the index event. Majority of them experienced at least moderate levels of post‐traumatic stress disorder (PTSD) problems over the 1‐year span. About 9.3% of participants showed a delayed onset of PTSD 6 months after. Furthermore, counter‐supportive behaviours and reexposure to violence played important roles in the maintenance of PTSD symptoms over time. Even though PTSD symptoms per se did not relate to bus driver's confidence in coping with aggressive passengers, the immediate post‐traumatic reaction—symptoms of acute stress disorder—showed a significant long‐term negative effect on bus drivers' confidence in dealing with aggressive passengers 12 months after. This study provided empirical evidence of the changing nature of PTSD symptoms over time among bus drivers.
Transcranial colour‐coded duplex of the intracranial large arteries
Authors: McKiernan Sharmaine , Selmes Christine 
Published: September 2017

AbstractTranscranial colour‐coded duplex (TCCD) is a non‐invasive ultrasound technique that assesses blood flow within the large arteries of the circle of Willis. In the clinical sonography world, it can be considered a relatively recent technique that is useful to assess cerebral haemodynamics in a variety of conditions. This article covers the anatomy of the circle of Willis, TCCD scanning and information on some common pathologies TCCD may be used to assess. It is important the sonographer is aware of TCCD imaging and of the intricacies involved in the technique.