TY  - JOUR
A1  - Choi, Chang-Hoon
A1  - Felder, Tim
A1  - Felder, Jörg
A1  - Tellmann, Lutz
A1  - Hong, Suk-Min
A1  - Wegener, Hans-Peter
A1  - Shah, N Jon
A1  - Ziemons, Karl
T1  - Design, evaluation and comparison of endorectal coils for hybrid MR-PET imaging of the prostate
JF  - Physics in Medicine & Biology
N2  - Prostate cancer is one of the most common cancers among men and its early detection is critical for its successful treatment. The use of multimodal imaging, such as MR-PET, is most advantageous as it is able to provide detailed information about the prostate. However, as the human prostate is flexible and can move into different positions under external conditions, it is important to localise the focused region-of-interest using both MRI and PET under identical circumstances. In this work, we designed five commonly used linear and quadrature radiofrequency surface coils suitable for hybrid MR-PET use in endorectal applications. Due to the endorectal design and the shielded PET insert, the outer face of the coils investigated was curved and the region to be imaged was outside the volume of the coil. The tilting angles of the coils were varied with respect to the main magnetic field direction. This was done to approximate the various positions from which the prostate could be imaged. The transmit efficiencies and safety excitation efficiencies from simulations, together with the signal-to-noise ratios from the MR images were calculated and analysed. Overall, it was found that the overlapped loops driven in quadrature were superior to the other types of coils we tested. In order to determine the effect of the different coil designs on PET, transmission scans were carried out, and it was observed that the differences between attenuation maps with and without the coils were negligible. The findings of this work can provide useful guidance for the integration of such coil designs into MR-PET hybrid systems in the future.
Y1  - 2020
U6  - https://doi.org/10.1088/1361-6560/ab87f8
SN  - 0031-9155
VL  - 65
IS  - 11
PB  - IOP
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Hoffstadt, Kevin
A1  - Pohen, Gino D.
A1  - Dicke, Max D.
A1  - Paulsen, Svea
A1  - Krafft, Simone
A1  - Zang, Joachim W.
A1  - Fonseca-Zang, Warde A. da
A1  - Leite, Athaydes
A1  - Kuperjans, Isabel
T1  - Challenges and prospects of biogas from energy cane as supplement to bioethanol production
JF  - Agronomy
N2  - Innovative breeds of sugar cane yield up to 2.5 times as much organic matter as conventional breeds, resulting in a great potential for biogas production. The use of biogas production as a complementary solution to conventional and second-generation ethanol production in Brazil may increase the energy produced per hectare in the sugarcane sector. Herein, it was demonstrated that through ensiling, energy cane can be conserved for six months; the stored cane can then be fed into a continuous biogas process. This approach is necessary to achieve year-round biogas production at an industrial scale. Batch tests revealed specific biogas potentials between 400 and 600 LN/kgVS for both the ensiled and non-ensiled energy cane, and the specific biogas potential of a continuous biogas process fed with ensiled energy cane was in the same range. Peak biogas losses through ensiling of up to 27% after six months were observed. Finally, compared with second-generation ethanol production using energy cane, the results indicated that biogas production from energy cane may lead to higher energy yields per hectare, with an average energy yield of up to 162 MWh/ha. Finally, the Farm²CBG concept is introduced, showing an approach for decentralized biogas production.
Y1  - 2020
U6  - https://doi.org/10.3390/agronomy10060821
SN  - 2073-4395
VL  - 10
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Akimbekov, Nuraly S.
A1  - Digel, Ilya
A1  - Sherelkhan, Dinara K.
A1  - Lutfor, Afzalunnessa B.
A1  - Razzaque, Mohammed S.
T1  - Vitamin D and the Host-Gut Microbiome: A Brief Overview
JF  - Acta Histochemica et Cytochemica
N2  - There is a growing body of evidence for the effects of vitamin D on intestinal host-microbiome interactions related to gut dysbiosis and bowel inflammation. This brief review highlights the potential links between vitamin D and gut health, emphasizing the role of vitamin D in microbiological and immunological mechanisms of inflammatory bowel diseases. A comprehensive literature search was carried out in PubMed and Google Scholar using combinations of keywords “vitamin D,” “intestines,” “gut microflora,” “bowel inflammation”. Only articles published in English and related to the study topic are included in the review. We discuss how vitamin D (a) modulates intestinal microbiome function, (b) controls antimicrobial peptide expression, and (c) has a protective effect on epithelial barriers in the gut mucosa. Vitamin D and its nuclear receptor (VDR) regulate intestinal barrier integrity, and control innate and adaptive immunity in the gut. Metabolites from the gut microbiota may also regulate expression of VDR, while vitamin D may influence the gut microbiota and exert anti-inflammatory and immune-modulating effects. The underlying mechanism of vitamin D in the pathogenesis of bowel diseases is not fully understood, but maintaining an optimal vitamin D status appears to be beneficial for gut health. Future studies will shed light on the molecular mechanisms through which vitamin D and VDR interactions affect intestinal mucosal immunity, pathogen invasion, symbiont colonization, and antimicrobial peptide expression.
Y1  - 2020
U6  - https://doi.org/10.1267/ahc.20011
SN  - 1347-5800
VL  - 53
IS  - 3
SP  - 33
EP  - 42
PB  - Japan Society of Histochemistry and Cytochemistry
CY  - Osaka
ER  - 
TY  - JOUR
A1  - Khayyam, Hamid
A1  - Jamali, Ali
A1  - Bab-Hadiashar, Alireza
A1  - Esch, Thomas
A1  - Ramakrishna, Seeram
A1  - Jalili, Mahdi
A1  - Naebe, Minoo
T1  - A Novel Hybrid Machine Learning Algorithm for Limited and Big Data Modeling with Application in Industry 4.0
JF  - IEEE Access
N2  - To meet the challenges of manufacturing smart products, the manufacturing plants have been radically changed to become smart factories underpinned by industry 4.0 technologies. The transformation is assisted by employment of machine learning techniques that can deal with modeling both big or limited data. This manuscript reviews these concepts and present a case study that demonstrates the use of a novel intelligent hybrid algorithms for Industry 4.0 applications with limited data. In particular, an intelligent algorithm is proposed for robust data modeling of nonlinear systems based on input-output data. In our approach, a novel hybrid data-driven combining the Group-Method of Data-Handling and Singular-Value Decomposition is adapted to find an offline deterministic model combined with Pareto multi-objective optimization to overcome the overfitting issue. An Unscented-Kalman-Filter is also incorporated to update the coefficient of the deterministic model and increase its robustness against data uncertainties. The effectiveness of the proposed method is examined on a set of real industrial measurements.
Y1  - 2020
U6  - https://doi.org/10.1109/ACCESS.2020.2999898
SN  - 2169-3536
VL  - 8
IS  - Art. 9108222
SP  - 111381
EP  - 111393
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Ramoshaba, Nthai E.
A1  - Huisman, Hugo W.
A1  - Lammertyn, Leandi
A1  - Kotliar, Konstantin
A1  - Schutte, Aletta E.
A1  - Smith, Wayne
T1  - Retinal microvasculature and masked hypertension in young adults: the African-PREDICT study
JF  - Hypertension Research
N2  - Masked hypertension is known to induce microvascular complications. However, it is unclear whether early microvascular changes are already occurring in young, otherwise healthy adults. We therefore investigated whether retinal microvascular calibers and acute responses to a flicker stimulus are related to masked hypertension. We used the baseline data of 889 participants aged 20–30 years who were taking part in the African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension. Clinic and 24-h ambulatory blood pressure were measured. The central retinal artery equivalent (CRAE) and central retinal vein equivalent were calculated from fundus images, and retinal vessel dilation was determined in response to flicker light-induced provocation. A smaller CRAE was observed in those with masked hypertension vs. those with normotension (157.1 vs. 161.2 measuring units, P < 0.001). In forward multivariable-adjusted regression analysis, only CRAE was negatively related to masked hypertension [adjusted R² = 0.267, β = −0.097 (95% CI = −0.165; −0.029), P = 0.005], but other retinal microvascular parameters were not associated with masked hypertension. In multivariable logistic regression analyses, masked hypertension [OR = 2.333, (95% CI = 1.316; 4.241), P = 0.004] was associated with a narrower CRAE. In young healthy adults, masked hypertension was associated with retinal arteriolar narrowing, thereby reflecting early microvascular alterations known to predict cardiovascular outcomes in later life.
Y1  - 2020
U6  - https://doi.org/10.1038/s41440-020-0487-0
SN  - 1348-4214
IS  - 43
SP  - 1231
EP  - 1238
PB  - Springer Nature
CY  - Osaka
ER  - 
TY  - JOUR
A1  - Gronsfeld, Richard
A1  - Joachim, Klubert
A1  - Malecha, Hartmut
T1  - 3-D-Visualisierung von vorhandenen Staubauwerken zur holistischen Planung und Überwachung
JF  - Wasserwirtschaft
Y1  - 2019
U6  - https://doi.org/10.1007/s35147-019-0075-x
SN  - 2192-8762
N1  - gedruckt in der Bereichsbibliothek Bayernallee unter der Signatur 13 Z 218 vorhanden
VL  - 109
IS  - 5
SP  - 82
EP  - 85
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Svaneborg, Carsten
A1  - Karimi-Varzaneh, Hossein Ali
A1  - Hojdis, Nils
A1  - Fleck, Franz
A1  - Everaers, Ralf
T1  - Multiscale approach to equilibrating model polymer melts
JF  - Physical Review E
N2  - We present an effective and simple multiscale method for equilibrating Kremer Grest model polymer melts of varying stiffness. In our approach, we progressively equilibrate the melt structure above the tube scale, inside the tube and finally at the monomeric scale. We make use of models designed to be computationally effective at each scale. Density fluctuations in the melt structure above the tube scale are minimized through a Monte Carlo simulated annealing of a lattice polymer model. Subsequently the melt structure below the tube scale is equilibrated via the Rouse dynamics of a force-capped Kremer-Grest model that allows chains to partially interpenetrate. Finally the Kremer-Grest force field is introduced to freeze the topological state and enforce correct monomer packing. We generate 15 melts of 500 chains of 10.000 beads for varying chain stiffness as well as a number of melts with 1.000 chains of 15.000 monomers. To validate the equilibration process we study the time evolution of bulk, collective, and single-chain observables at the monomeric, mesoscopic, and macroscopic length scales. Extension of the present method to longer, branched, or polydisperse chains, and/or larger system sizes is straightforward.
Y1  - 2016
U6  - https://doi.org/10.1103/PhysRevE.94.032502
SN  - 2470-0053
VL  - 94
IS  - 032502
PB  - AIP Publishing
CY  - Melville, NY
ER  - 
TY  - JOUR
A1  - Schwab, Lukas
A1  - Hojdis, Nils
A1  - Lacayo, Jorge
A1  - Wilhelm, Manfred
T1  - Fourier-Transform Rheology of Unvulcanized, Carbon Black Filled Styrene Butadiene Rubber
JF  - Macromolecular Materials and Engineering
N2  - Rubber materials filled with reinforcing fillers display nonlinear rheological behavior at small strain amplitudes below γ0 < 0.1. Nevertheless, rheological data are analyzed mostly in terms of linear parameters, such as shear moduli (G′, G″), which loose their physical meaning in the nonlinear regime. In this work styrene butadiene rubber filled with carbon black (CB) under large amplitude oscillatory shear (LAOS) is analyzed in terms of the nonlinear parameter I3/1. Three different CB grades are used and the filler load is varied between 0 and 70 phr. It is found that I3/1(φ) is most sensitive to changes of the total accessible filler surface area at low strain amplitudes (γ0 = 0.32). The addition of up to 70 phr CB leads to an increase of I3/1(φ) by a factor of more than ten. The influence of the measurement temperature on I3/1 is pronounced for CB levels above the percolation threshold.
Y1  - 2016
U6  - https://doi.org/10.1002/mame.201500356
SN  - 1439-2054
VL  - 301
IS  - 4
SP  - 457
EP  - 468
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Harish, Ajay B.
A1  - Wriggers, Peter
A1  - Jungk, Juliane
A1  - Hojdis, Nils
A1  - Recker, Carla
T1  - Mesoscale Constitutive Modeling of Non-Crystallizing Filled Elastomers
JF  - Computational Mechanics
N2  - Elastomers are exceptional materials owing to their ability to undergo large deformations before failure. However, due to their very low stiffness, they are not always suitable for industrial applications. Addition of filler particles provides reinforcing effects and thus enhances the material properties that render them more versatile for applications like tyres etc. However, deformation behavior of filled polymers is accompanied by several nonlinear effects like Mullins and Payne effect. To this day, the physical and chemical changes resulting in such nonlinear effect remain an active area of research. In this work, we develop a heterogeneous (or multiphase) constitutive model at the mesoscale explicitly considering filler particle aggregates, elastomeric matrix and their mechanical interaction through an approximate interface layer. The developed constitutive model is used to demonstrate cluster breakage, also, as one of the possible sources for Mullins effect observed in non-crystallizing filled elastomers.
Y1  - 2016
U6  - https://doi.org/10.1007/s00466-015-1251-1
SN  - 1432-0924
VL  - 57
SP  - 653
EP  - 677
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Hentschke, Reinhard
A1  - Hager, Jonathan
A1  - Hojdis, Nils
T1  - Molecular Modeling Approach to the Prediction of Mechanical Properties of Silica-Reinforced Rubbers
JF  - Journal of Applied Polymer Science
N2  - Recently, we have suggested a nanomechanical model for dissipative loss in filled elastomer networks in the context of the Payne effect. The mechanism is based on a total interfiller particle force exhibiting an intermittent loop, due to the combination of short-range repulsion and dispersion forces with a long-range elastic attraction. The sum of these forces leads, under external strain, to a spontaneous instability of “bonds” between the aggregates in a filler network and attendant energy dissipation. Here, we use molecular dynamics simulations to obtain chemically realistic forces between surface modified silica particles. The latter are combined with the above model to estimate the loss modulus and the low strain storage modulus in elastomers containing the aforementioned filler-compatibilizer systems. The model is compared to experimental dynamic moduli of silica filled rubbers. We find good agreement between the model predictions and the experiments as function of the compatibilizer's molecular structure and its bulk concentration.
KW  - theory and modeling
KW  - supramolecular structures
KW  - rubber
KW  - mechanical properties
KW  - elastomers
Y1  - 2014
U6  - https://doi.org/10.1002/app.40806
SN  - 1097-4628
VL  - 131
IS  - 18
SP  - 1
EP  - 9
PB  - Wiley
CY  - New York, NY
ER  -