TY  - JOUR
A1  - Holtrup, S.
A1  - Sadeghfam, Arash
A1  - Heuermann, Holger
A1  - Awakowicz, P.
T1  - Characterization and optimization technique for microwave-driven high-intensity discharge lamps using hot S-parameters
JF  - IEEE transactions on microwave theories and techniques
N2  - High-intensity discharge lamps can be driven by radio-frequency signals in the ISM frequency band at 2.45 GHz, using a matching network to transform the impedance of the plasma to the source impedance. To achieve an optimal operating condition, a good characterization of the lamp in terms of radio frequency equivalent circuits under operating conditions is necessary, enabling the design of an efficient matching network. This paper presents the characterization technique for such lamps and presents the design of the required matching network. For the characterization, a high-intensity discharge lamp was driven by a monofrequent large signal at 2.45 GHz, whereas a frequency sweep over 300 MHz was performed across this signal to measure so-called small-signal hot S-parameters using a vector network analyzer. These parameters are then used as an equivalent load in a circuit simulator to design an appropriate matching network. Using the measured data as a black-box model in the simulation results in a quick and efficient method to simulate and design efficient matching networks in spite of the complex plasma behavior. Furthermore, photometric analysis of high-intensity discharge lamps are carried out, comparing microwave operation to conventional operation.
Y1  - 2014
U6  - https://doi.org/10.1109/TMTT.2014.2342652
SN  - 0018-9480
VL  - 62
IS  - 10
SP  - 2471
EP  - 2480
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Hoehr, Cornelia
A1  - Paulßen, Elisabeth
A1  - Benard, Francois
A1  - Lee, Chris Jaeil
A1  - Hou, Xinchi
A1  - Badesso, Brian
A1  - Ferguson, Simon
A1  - Miao, Qing
A1  - Yang, Hua
A1  - Buckley, Ken
A1  - Hanemaayer, Victoire
A1  - Zeisler, Stefan
A1  - Ruth, Thomas
A1  - Celler, Anna
A1  - Schaffer, Paul
T1  - ⁴⁴ᶢSc production using a water target on a 13 MeV cyclotron
JF  - Nuclear medicine and biology
N2  - Access to promising radiometals as isotopes for novel molecular imaging agents requires that they are routinely available and inexpensive to obtain. Proximity to a cyclotron center outfitted with solid target hardware, or to an isotope generator for the metal of interest is necessary, both of which can introduce significant hurdles in development of less common isotopes. Herein, we describe the production of ⁴⁴Sc (t₁⸝₂ = 3.97 h, Eavg,β⁺ = 1.47 MeV, branching ratio = 94.27%) in a solution target and an automated loading system which allows a quick turn-around between different radiometallic isotopes and therefore greatly improves their availability for tracer development. Experimental yields are compared to theoretical calculations.
Y1  - 2014
U6  - https://doi.org/10.1016/j.nucmedbio.2013.12.016
SN  - 1872-9614
VL  - 41
IS  - 5
SP  - 401
EP  - 406
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Heuermann, Holger
A1  - Finger, Torsten
T1  - 2.45 GHz Plasma Powered Spark Plug by Thermal and EM-Optimization
Y1  - 2014
N1  - Ansys High Frequency Simulation Conference - AHFSC 2014, Munich; 02/2014
ER  - 
TY  - CHAP
A1  - Heuermann, Holger
A1  - Finger, Torsten
ED  - Günther, Michael
T1  - Microwave Spark Plug for Very High-Pressure Conditions
T2  - Ignition systems for gasoline engines
Y1  - 2014
SP  - 269
EP  - 282
PB  - DCM Druck
CY  - Meckenheim
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  - 
TY  - JOUR
A1  - Heinze, Daniel
A1  - Mang, Thomas
A1  - Peter, Karin
A1  - Möller, Martin
A1  - Weichold, Oliver
T1  - Synthesis of low molecular weight poly(vinyl acetate) and its application as plasticizer
JF  - Journal of applied polymer science
N2  - Poly(vinyl acetate), PVAc, with a degree of polymerization Xn = 10 was prepared by chain-transfer radical polymerization using carbon tetrachloride and used as oligomeric plasticizer for commercial PVAc. However, the chlorinated chain ends cause a low thermal stability requiring mild Cl/H substitution. The product exhibits high thermal stability and excellent melt-compounding properties. Blends of oligomeric and commercial PVAc show single glass transition temperatures which decrease with higher oligomer content and exhibit small negative deviations from Fox' linear additivity rule. This indicates plasticization and miscibility being mainly due to entropic effects. Injection-moulded thick specimens show ductile behaviour at oligomer contents >10 wt %, while sheets with a thickness of 0.2–0.5 mm appear flexible already at 7.5 wt %. The oxygen permeability coefficients are an order of magnitude lower than those of low-density polyethylene. Due to the sum of their properties, the plasticized sheets present a promising alternative in the preparation of barrier materials.
Y1  - 2014
U6  - https://doi.org/10.1002/app.40226
SN  - 1097-4628 (E-Journal); 0021-8995 (Print)
VL  - 131
IS  - 9
SP  - Article No. 40226
PB  - Wiley
CY  - New York
ER  - 
TY  - JOUR
A1  - Heine, A.
A1  - Herrmann, G.
A1  - Selmer, Thorsten
A1  - Terwesten, F.
A1  - Buckel, W.
A1  - Reuter, K.
T1  - High resolution crystal structure of clostridium propionicum β-Alanyl-CoA:Ammonia Lyase, a new member of the "Hot Dog Fold" protein superfamily
JF  - Proteins
N2  - Clostridium propionicum is the only organism known to ferment β-alanine, a constituent of coenzyme A (CoA) and the phosphopantetheinyl prosthetic group of holo-acyl carrier protein. The first step in the fermentation is a CoA-transfer to β-alanine. Subsequently, the resulting β-alanyl-CoA is deaminated by the enzyme β-alanyl-CoA:ammonia lyase (Acl) to reversibly form ammonia and acrylyl-CoA. We have determined the crystal structure of Acl in its apo-form at a resolution of 0.97 Å as well as in complex with CoA at a resolution of 1.59 Å. The structures reveal that the enyzme belongs to a superfamily of proteins exhibiting a so called “hot dog fold” which is characterized by a five-stranded antiparallel β-sheet with a long α-helix packed against it. The functional unit of all “hot dog fold” proteins is a homodimer containing two equivalent substrate binding sites which are established by the dimer interface. In the case of Acl, three functional dimers combine to a homohexamer strongly resembling the homohexamer formed by YciA-like acyl-CoA thioesterases. Here, we propose an enzymatic mechanism based on the crystal structure of the Acl·CoA complex and molecular docking. Proteins 2014; 82:2041–2053. © 2014 Wiley Periodicals, Inc.
Y1  - 2014
U6  - https://doi.org/10.1002/prot.24557
SN  - 1097-0134 (E-Journal); 0887-3585 (Print)
VL  - 82
IS  - 9
SP  - 2041
EP  - 2053
PB  - Wiley-Liss
CY  - New York
ER  - 
TY  - CHAP
A1  - Heckl, O. H.
A1  - Weiler, Sascha
A1  - Fleischhaker, Robert
A1  - Gebs, Raphael
A1  - Budnicki, Aleksander
A1  - Wolf, M.
A1  - Kleinbauer, Jochen
A1  - Russ, S.
A1  - Kumkar, M.
A1  - Sutter, Dirk H.
ED  - Heisterkamp, Alexander
ED  - Herman, Peter R.
ED  - Meunier, Michael
ED  - Nolte, Stefan
T1  - Industry-grade high average power femtosecond light source
T2  - Frontiers in ultrafast optics: Biomedical, scientific, and industrial applications XIV : 1 Februar 2014, San Francisco, USA. - (SPIE proceedings series ; 8972)
Y1  - 2014
U6  - https://doi.org/10.1117/12.2039337
N1  - Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XIV <2, 2014, San Francisco, CA>
SP  - 89720P
EP  - 89720P-7
PB  - SPIE, International Society for Optical Engineering
ER  - 
TY  - JOUR
A1  - Handtke, Stefan
A1  - Volland, Sonja
A1  - Methling, Karen
A1  - Albrecht, Dirk
A1  - Becher, Dörte
A1  - Nehls, Jenny
A1  - Bongaerts, Johannes
A1  - Maurer, Karl-Heinz
A1  - Lalk, Michael
A1  - Liesegang, Heiko
A1  - Voigt, Birgit
A1  - Daniel, Rolf
A1  - Hecker, Michael
T1  - Cell physiology of the biotechnological relevant bacterium Bacillus pumilus - An omics-based approach
JF  - Journal of Biotechnology
N2  - Members of the species Bacillus pumilus get more and more in focus of the biotechnological industry as potential new production strains. Based on exoproteome analysis, B. pumilus strain Jo2, possessing a high secretion capability, was chosen for an omics-based investigation. The proteome and metabolome of B. pumilus cells growing either in minimal or complex medium was analyzed. In total, 1542 proteins were identified in growing B. pumilus cells, among them 1182 cytosolic proteins, 297 membrane and lipoproteins and 63 secreted proteins. This accounts for about 43% of the 3616 proteins encoded in the B. pumilus Jo2 genome sequence. By using GC–MS, IP-LC/MS and H NMR methods numerous metabolites were analyzed and assigned to reconstructed metabolic pathways. In the genome sequence a functional secretion system including the components of the Sec- and Tat-secretion machinery was found. Analysis of the exoproteome revealed secretion of about 70 proteins with predicted secretion signals. In addition, selected production-relevant genome features such as restriction modification systems and NRPS clusters of B. pumilus Jo2 are discussed.
Y1  - 2014
U6  - https://doi.org/10.1016/j.jbiotec.2014.08.028
SN  - 1873-4863 (E-Journal); 0168-1656 (Print)
IS  - 192(A)
SP  - 204
EP  - 214
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Handtke, Stefan
A1  - Schroeter, Rebecca
A1  - Jürgen, Britta
A1  - Methling, Karen
A1  - Schlüter, Rabea
A1  - Albrecht, Dirk
A1  - Hijum, Sacha A. F. T. van
A1  - Bongaerts, Johannes
A1  - Maurer, Karl-Heinz
A1  - Lalk, Michael
A1  - Schweder, Thomas
A1  - Hecker, Michael
A1  - Voigt, Birgit
T1  - Bacillus pumilus reveals a remarkably high resistance to hydrogen peroxide provoked oxidative stress
JF  - PLOS one
N2  - Bacillus pumilus is characterized by a higher oxidative stress resistance than other comparable industrially relevant Bacilli such as B. subtilis or B. licheniformis. In this study the response of B. pumilus to oxidative stress was investigated during a treatment with high concentrations of hydrogen peroxide at the proteome, transcriptome and metabolome level. Genes/proteins belonging to regulons, which are known to have important functions in the oxidative stress response of other organisms, were found to be upregulated, such as the Fur, Spx, SOS or CtsR regulon. Strikingly, parts of the fundamental PerR regulon responding to peroxide stress in B. subtilis are not encoded in the B. pumilus genome. Thus, B. pumilus misses the catalase KatA, the DNA-protection protein MrgA or the alkyl hydroperoxide reductase AhpCF. Data of this study suggests that the catalase KatX2 takes over the function of the missing KatA in the oxidative stress response of B. pumilus. The genome-wide expression analysis revealed an induction of bacillithiol (Cys-GlcN-malate, BSH) relevant genes. An analysis of the intracellular metabolites detected high intracellular levels of this protective metabolite, which indicates the importance of bacillithiol in the peroxide stress resistance of B. pumilus.
Y1  - 2014
U6  - https://doi.org/10.1371/journal.pone.0085625
SN  - 1932-6203
VL  - 9
IS  - 1
PB  - PLOS
CY  - San Francisco
ER  -