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Impact of field strength and RF excitation on abdominal diffusion-weighted magnetic resonance imaging

World journal of Radiology 2013年第9期5卷 334-344页

作者： Philipp Riffel Raghuram K Rao Stefan Haneder Mathias Meyer Stefan O Schoenberg henrik j michaely Department of Clinical Radiology and Nuclear Medicine University Medical Center Mannheim Medical Faculty Mannheim-Heidelberg University the Russel H. Morgan Department of Radiology and Radiologic Science the Johns Hopkins Hospital

AIM:To retrospectively and prospectively compare diffusion-weighted(DW)images in the abdomen in a1.5T system and 3.0T systems with and without twochannel functionality for ***:DW images of the abdomen were obtained on 1.5T and 3.0T(with and without two-channel functionality for B1shimming)scanners on 150 patients(retrospective study population)and 10 volunteers(prospective study population).Eight regions were selected for clinical significance or artifact susceptibility(at higher field strengths).Objective grading quantified signal-to-noise ratio(SNR),and subjective evaluation qualified image quality,ghosting artifacts,anddiagnostic *** significance was calculated usingχ2tests(categorical variables)and independent two-sided t tests or Mann-Whitney U tests(continuous variables).RESULTS:The 3.0T using dual-source parallel transmit(dpTX 3.0T)provided the significantly highest SNRs in nearly all *** regions susceptible to artifacts at higher field strengths(left lobe of liver,head of pancreas),the SNR was better or similar to the 1.5T ***,both dpTX 3.0T and 1.5T systems provided higher image quality,diagnostic value,and less ghosting artifact(P<0.01,most values)compared to the 3.0T system without dual-source parallel transmit(non-dpTX 3.0T).CONCLUSION:The dpTX 3.0T scanner provided the highest *** image quality,lack of ghosting,and diagnostic value were equal to or outperformed most currently used systems.

关键词： Abdominal imaging Diffusion weighted 3.0T Radiofrequency excitation Signal-to-noise ratio

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Evaluation of a handheld creatinine measurement device for real-time determination of serum creatinine in radiology departments

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World journal of Radiology 2012年第7期4卷 328-334页

作者： Stefan Haneder Alexandra Gutfleisch Claudia Meier joachim Brade Dieter Hannak Stefan O Schoenberg Christoph R Becker henrik j michaely Institute of Clinical Radiology and Nuclear Medicine University Medical Centre Mannheim University of Heidelberg 68167 Mannheim Germany Institute for Clinical Statistics University Medical Centre Mannheim University of Heidelberg 68167 Mannheim Germany Institute of Clinical Chemistry University Medical Centre Mannheim University of Heidelberg 68167 Mannheim Germany Institute of Clinical Radiology Hospital Munich-Grosshadern University of Munich 81377 Munich Germany

AIM: To assess the feasibility/accuracy of a commercial handheld device in the context of increased demand for point-of-care serum creatinine (SCr) determination. METHODS: In this institutional review board-approved, prospective study, 401 patients referred for contrastenhanced computed tomography were included at two centres. Capillary (c)SCr was determined using two devices A+B and venous (v)SCr was determined in the centre's laboratory. Method comparison statistics for both centres and for vSCr1.2 mg/dL, receiver operating characteristic analysis, negative predictive values (NPV), sensitivity and specificity were calculated pre-/ post-curve offset correction with vSCr. RESULTS: Pearson's coefficients for cSCr vs vSCr were: centre 1-A:0.93/B:0.92; centre 2-A:0.85/B:0.82 (all P 1.2 mg/dL. The area under the receiver operating characteristic curves showed a high accuracy for cSCr, but the device underestimated SCr, which was confirmed by Bland-Altman plot. Addition of the offset correction factor to the original data from centre 1 resulted in an improvement in sensitivity for detecting patients at risk (> 1.2 mg/dL), whilst maintaining acceptable specificity and improving NPV. CONCLUSION: This study showed the feasibility of SCr determination using the evaluated handheld device in a routine clinical setting. The device showed high sensitivity and high NPV, but may significantly underestimate SCr without offset correction to local laboratories.

关键词： Contrast-medium-induced nephropathy Nephrogenic systemic fibrosis Point of care testing Serum creatinine determination StatSensor

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Particle size and packing characterization by diffuse light transmission

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Particuology 2012年第5期10卷 619-627页

作者： henrik Ehlers jyrki Heinmki jouko Yliruusi Division of Pharmaceutical Technology Faculty of Pharmacy P.O. Box 56 (Viikinkaari 5 E) FI-00014 University of Helsinki Finland Pharmaceutical Sciences Laboratory Department of Biosciences bo Akademi University BioCity Artillerigatan 6 20520 Turku Finland Department of Pharmacy Faculty of Medicine University of Tartu Nooruse 1 50411 Tartu Estonia

Particle size, packing density and blend composition of glass ballotini, microcrystalline cellulose pellets and theophylline granules were studied by diffuse light transmission. Diffuse visible light was directed to the sample and the intensity of the light transmitted to the opposite side of the sample was measured through a diffusing lens using a phototransistor, Light transmission was found to decrease with decreasing particle size and with increasing packing density, There was a correlation, though somewhat irregular, between light transmission and particle size for glass ballotini and microcrystalline cellulose pellets, and a strong near-linear correlation between light transmission and particle size for theophylline granules, The effect of packing density on light transmission was significant, Differentiating the composition of binary blends of microcrystalline cellulose pellets and glass ballotini and blends of theophylline granules was found possible on the basis of light transmission, The method proposed showed potential as a rapid, simple and inexpensive analytical tool for basic process diagnostics,

关键词： Light transmissionParticle sizePacking densityConvectionSegregation

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Infrared spectroscopic probing of dimethylamine clusters in an Ar matrix

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journal of Environmental Sciences 2016年第2期28卷 51-59页

作者： Siyang Li henrik G.Kjaergaard Lin Du Environment Research Institute Shandong University Shanda South Road 27 Shandong 250100 China Department of Chemistry University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen φ Denmark

Amines have many atmospheric sources and their clusters play an important role in aerosol nucleation processes. Clusters of a typical amine, dimethylamine（DMA）, of different sizes were measured with matrix isolation IR（infrared） and NIR（near infrared）spectroscopy. The NIR vibrations are more separated and therefore it is easier to distinguish different sizes of clusters in this region. The DMA clusters, up to DMA tetramer, have been optimized using density functional methods, and the geometries, binding energies and thermodynamic properties of DMA clusters were obtained. The computed frequencies and intensities of NH-stretching vibrations in the DMA clusters were used to interpret the experimental spectra. We have identified the fundamental transitions of the bonded NH-stretching vibration and the first overtone transitions of the bonded and free NH-stretching vibration in the DMA clusters. Based on the changes in vibrational intensities during the annealing processes, the growth of clusters was clearly observed. The results of annealing processes indicate that DMA molecules tend to form larger clusters with lower energies under matrix temperatures, which is also supported by the calculated reaction energies of cluster formation.

关键词： Matrix isolation Infrared(IR) spectroscopy Dimethylamine clusters Aerosol nucleation

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ICT and E-learning, the Road to Hell or Paradise? The Need for a Strategic Thinking on Sustainable Digital Environment for E-learning

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开放教育研究 2005年第3期11卷 58-61页

作者： henrik Hansson Institute of International Education Stockholms University Sweden

The paper mainly discusses the negative sides of technology in education that have arisen from the the rapid development of technology.

关键词：建构主义在线学习现代教育技术学习环境自主学习利弊分析

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The synergies of SMAP enhanced and MODIS products in a random forest regression for estimating 1 km soil moisture over Africa using Google Earth Engine

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Big Earth Data 2024年第1期8卷 33-57页

作者： Farzane Mohseni Amirhossein Ahrari jan-henrik Haunert Carsten Montzka Institute of Geodesy and Geoinformation University of BonnBonnGermany Water Energy and Environmental Engineering Research UnitUniversity of OuluOuluFinland Institute of Bio-and Geosciences:Agrosphere(IBG-3) Forschungszentrum Jülich GmbHJülichGermany

Due to the coarse scale of soil moisture products retrieved from passive microwave observations(SMPMW),several downscaling methods have been developed to enable regional scale ***,it can be challenging for users to access final data products and algorithms,as well as managing different data sources and formats,various data processing methods,and the complexity of the workflows from raw data to information ***,the Google Earth Engine(GEE),which as of late offers SMPMW,is used to implement a workflow for retrieving 1 km SM at a depth of 0-5 cm using MODIS optical/thermal measurements,the SM_(PMW)coarse scale product,and a random forest *** proposed method was implemented on the African continent to estimate weekly SM *** results of this study were evaluated against in-situ measurements of three validation ***,in comparison to the original SM_(PMW)product,which was limited by a spatial resolution of only 9 km,this method is able to estimate SM at 1 km spatial resolution with acceptable accuracy(an average correlation coefficient of 0.64 and a ubRMSD of 0.069 m^(3)/m^(3)).The results show that the proposed method in GEE provides a precise estimation of SM with a higher spatial resolution across the entire continent.

关键词： Soil moisture SMAP Google Earth Engine random forest regression MODIS

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Severe steroid refractory gastritis induced by Nivolumab: A case report

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World journal of Gastroenterology 2020年第16期26卷 1971-1978页

作者： Helene Hjorth Vindum jØrgen S Agnholt Anders Winther Moelby Nielsen Mette Bak Nielsen henrik Schmidt Department of Oncology Aarhus University HospitalAarhus 8200Denmark Department of Gastroenterology Aarhus University HospitalAarhus 8200Denmark Department of Pathology Aarhus University HospitalAarhus 8200Denmark

BACKGROUND Immune checkpoint inhibitors are widely used for treatment of many advanced *** gastrointestinal(GI)side effects,such as diarrhea and colitis,are common,but upper GI side effects are rarely ***,the correct treatment of upper GI adverse events has been less frequently *** SUMMARY We describe a case of a 16-year-old woman with stage IIIb malignant melanoma treated with adjuvant monotherapy using *** patient developed severe gastritis after six series of Nivolumab with weight loss,nausea,and *** was no effect of intravenous steroids,but the patient′s condition resolved after administration of *** This case report supports the same treatment for gastritis as for colitis,which is in line with current guidelines.

关键词： Gastritis Immune checkpoint inhibitors Nivolumab Case report Immune-related adverse events Infliximab

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Structural and chemical changes in pyrogenic organic matter aged in a boreal forest soil

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Pedosphere 2023年第3期33卷 436-447页

作者： jari HYVÄLUOMA Arttu MIETTINEN Riikka KESKINEN Kimmo RASA henrik LINDBERG Häme University of Applied Sciences Mustialantie 105Mustiala FI-31310(Finland) Department of Physics University of JyväskyläP.O.Box 35JyväskyläFI-40014(Finland) Natural Resources Institute Finland Tietotie 4Jokioinen FI-31600(Finland) Häme University of Applied Sciences Visamäentie 35 AP.O.Box 230Hämeenlinna FI-13101(Finland)

Pyrogenic organic matter(PyOM)is formed during wildfires and prescribed burnings or produced intentionally in the form of biochar for soil amendment *** is attracting a growing scientific and practical interest due to its important role in the global carbon cycle and agronomic applications as a soil *** of the studies on the physicochemical properties of PyOM have been conducted using fresh biochars even though the characteristics of PyOM are expected to alter due to aging processes in soil *** this paper,we report the results of a study that utilized X-ray microtomography and elemental analysis to investigate the chemical and structural changes in the PyOM formed during prescribed burning events and aged thereafter for 1–71 years in a boreal forest *** results indicate that changes in elemental composition occurred at decadal timescales,and an apparent steady state was reached ca.30 years after PyOM formation and exposure to the *** such timescales,PyOM was able to retain its porous structure originating from the cellular structure of the initial wood ***,structural analysis revealed several effects of aging on the pore structure,such as the formation of surface coating layers,pore fillings,and *** changes may alter pore size distribution and accessibility of the pores and further alter the influence of PyOM on soil functions,such as the transfer and retention of water and nutrients in PyOM pores.

关键词： biochar charcoal chronosequence porosity prescribed burning soil amendment X-ray microtomography

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New approach for particle size and shape analysis of iron-based oxygen carriers at multiple oxidation states

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Particuology 2024年第7期90卷 493-503页

作者： Victor Purnomo Marcelo Dal Belo Takehara Robin Faust Lidiya Abdisa Ejjeta henrik Leion Division of Energy and Materials Department of Chemistry and Chemical EngineeringChalmers University of TechnologyGöteborg 41258Sweden Division of Energy Science Department of Engineering Sciences and MathematicsLuleåUniversity of TechnologyLuleå97187Sweden

One of the crucial issues in the chemical looping technology lies in its bed material:the oxygen *** size analysis of an oxygen carrier is important since in a fluidized bed the material can only work well within a specific size *** the favorable size ranges for oxygen carrier materials have already been reported,none of the published studies has analyzed the particle size and shape of oxygen carriers in ***,the effect of oxygen carriers'oxidation degree on such properties has not been considered *** study aimed to report the particle size and shape analysis of five iron-based oxygen carriers,one natural ore,one synthetic material,and three residue products,at different oxidation degrees using dynamic image analysis(DIA).The oxygen carriers were prepared at different mass conversion degrees in a fluidized bed batch *** size distribution,sphericity,and aspect ratio of the oxygen carrier particles were examined experimentally using a Camsizer *** results show that the DIA method was successfully able to analyze the particle size and shape of our oxygen carriers with satisfying accuracy for *** oxidation state of the investigated materials seems to only affect the particle size and shape of oxygen carriers to a minor ***,exposures to redox cycles in a fluidized bed reactor may alter the particle size and shape of most oxygen carriers.

关键词： Oxygen carrier Size and shape analysis Dynamic image analysis Oxidation state Fluidized bed Chemical looping

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Identification of non-linear autoregressive models with exogenous inputs for room air temperature modelling

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Energy and AI 2022年第3期9卷 78-87页

作者： Christian Ankerstjerne Thilker Peder Bacher Davide Cali henrik Madsen Technical University of Denmark Department of Applied Mathematics and Computer ScienceAsmussens AlléBuilding 303BDK-2800 Kgs.LyngbyDenmark

This paper proposes non-linear autoregressive models with exogenous inputs to model the air temperature ineach room of a Danish school building connected to the local district heating network. To obtain satisfactorymodels, the authors find it necessary to estimate the solar radiation effect as a function of the time of the dayusing a B-spline basis expansion. Furthermore, this paper proposes a method for estimating the valve positionof the radiator thermostats in each room using modified Hermite polynomials to ensure monotonicity of theestimated curve. The non-linearities require a modification in the estimation procedure: Some parametersare estimated in an outer optimisation, while the usual regression parameters are estimated in an inneroptimisation. The models are able to simulate the temperature 24 h ahead with a root-mean-square-errorof the predictions between 0.25℃ and 0.6℃. The models seem to capture the solar radiation gain in away aligned with expectations. The estimated thermostatic valve functions also seem to capture the importantvariations of the individual room heat inputs.

关键词： Time series analysis Non-linear models District heating Smart energy systems

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