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When deprived of essential nutrients, the non-diazotrophic cyanobacterium Synechococcus sp. strain PCC 7942 undergoes a proteolytic degradation of the phycobiliproteins, its major light-harvesting pigments. This process is known as chlorosis. This paper presents evidence that the degradation of phycobiliproteins is part of an acclimation process in which growing cells differentiate into non-pigmented cells able to endure long periods of starvation. The time course of degradation processes differs for various photosynthetic pigments, for photosystem I and photosystem II activities and is strongly influenced by the illumination and by the experimental conditions of nutrient deprivation. Under standard experimental conditions of combined nitrogen deprivation, three phases of the differentiation process can be defined. The first phase corresponds to the well-known phycobiliprotein degradation, in phase 2 the cells lose chlorophyll a prior to entering phase 3, the fully differentiated state, in which the cells are still able to regenerate pigmentation after the addition of nitrate to the culture. An analysis of the protein synthesis patterns by two-dimensional gel electrophoresis during nitrogen starvation indicates extensive differential gene expression, suggesting the operation of tight regulatory mechanisms.

For the single step synthesis of dimethyl ether (DME) from synthesis gas a Cu/ZnO/Al 2 O 3 -catalyst has been prepared using flame-spray pyrolysis. The resulting powder was co-mixed with γ-alumina to give an admixed system for DME production. The flame-made catalyst was analyzed using the BET method, in situ XRD, N 2 O decomposition, TPR and XPS. These studies unraveled that the catalyst exhibited a high Cu surface area including good contact with zinc oxide and alumina as well as small Cu particles resulting in high catalytic activity and product selectivity, also in comparison to a commercially available catalyst.

This article contains sections titled: 1. General Plug Flow Reactor Characteristics 1.1. Fundamental Types of Chemical Reactors 1.2. Flow Patterns in Tubular Reactors 1.3. PFR Heating and Cooling via Tube Wall 1.4. Mass and Energy Balance 1.5. Adiabatic Temperature Increase 1.6. Pressure Drop 1.7. Residence Time Distribution 1.8. Dimensional Analysis of PFRs for Design and Scale-Up 2. PFR Types and Configurations 2.1. Adiabatic PFRs 2.1.1. Single-Stage Adiabatic PFR 2.1.2. Multistage PFRs with Interstage Heat Exchange 2.1.3. Stepwise Cold Shot Cooling 2.1.4. Feed-Effluent Heat Exchange 2.2. Polytropic PFRs 2.2.1. Jacketed PFRs 2.2.2. Radiation Heating 2.2.3. Tubular Loop Reactor 2.3. Multitubular PFR Configurations 3. Technical Applications 3.1. General Aspects 3.2. Large Scale Commercial Applications 3.2.1. Olefins by Steam Cracking of Naphtha 3.2.2. Gas Oil Cracking in the FCC Riser Reactor 3.2.3. Vinyl Chloride Production by EDC Dehydrochlorination 3.2.4. High Pressure Ethylene Polymerization for Low Density Polyethylene (LDPE) Polyethylene 3.3. Other Commercial Applications 3.3.1. Gas Phase Halogenation of Methane and Light Alkanes 3.3.2. HCN-Production in the Degussa BMA Process 3.3.3. Ketene via Acetic Acid or Acetone Cracking 3.3.4. Ethylene Glycol via Ethylene Oxide Hydrolysis 3.3.5. Various Additional Applications 3.4. Research and Development

Purpose : To review the survival, cure rate, and pattern of relapse or progression of patients with histologically confirmed Stage I testicular seminoma who inderwent orchiectomy and radiation therapy to paraaortic lymphatics only. The pelvic ipsilateral lymph nodes were not irradiated. Methods and Materials : Between 1978 and 1992, 150 patients with Stages I or II testicular seminoma received treatment at the Department of Radiation Oncology of the University of Wuerzburg. The distribution by stage was Stage I, 117 patients of which 93 were pT1 N0 M0 and 24 were pT2 N0 M0. Four patients were staged as Stage II (pT3 N0 M0), and in 29 patients the T Stage was not specified. Eighty-six patients from the 117 Stage I (pT1-pT2, N0 M0 according to the TNM classification) seminoma received postorchiectomy irradiation, and are analyzed for outcome in this article. The distribution of the Stage I patients by pT Stage was 71 pT1 and 15 pT2 patients. All these 86 patients had their paraaortic nodes (the bioligical target volume extending from top of L1 to the bottom of L5) irradiated with four field technique. Tumor dose was specified at normalization point along the central axis. The median tumor dose was 30 Gy given in 1.8−2.0 Gy fractions. Elective irradiation to the ipsilateral hemipelvis (iliac nodes) was totally abandoned. Results : The 10-year disease-free survival and overall survival were 95.3 and 100%. No recurrence in the irradiated field was noted. Four patients (4.7%) experienced relapse of disease outside the treated volume. The most common site of solitary failure was the ipsilateral hemipelvis (one iliacal and one inguinal). One patient developed metastatic disease to the lung. One patient developed a mediastinal recurrence with superior vena cava syndrome and was successfully salvaged by mediastinal irradiation and chemotherapy. Conclusion : Recommendation for the future management of Stage I seminoma include: reduced biological target volume to the paraaortal lymph nodes (from lumbar vertebra L1 to L5). Compute elimination of irradiation to the pelvic nodes is warranted. Radiation dose should no exceed 30 Gy.

An experimental investigation in a tube wall reactor with catalyst-coated inner wall is presented. Yields of formaldehyde of more than 70% can be obtained in the selective methanol dehydrogenation over alkalialuminate. Models for the reactor and the system of most important homogeneous reactions are derived. Different models describing the catalytic action are proposed. The results can only be explained by a new type of catalytic reaction, not described so far in the literature. Reducing gases like hydrogen and methanol lead to a volatilization of material from alkalialuminate which apparently catalyzes the dehydrogenation in the gas phase. Calculations and experimental evidence lead to the conclusion that this material should be sodium atoms. These are engaged in the homogeneous radical chain reaction by regulating the concentration of hydrogen atoms.

Laser-Doppler vibrometry (LDV) is a proven technique for vibration analysis of mechanical structures. A wavelength of 633 nm is usually employed because of the availability of the relatively inexpensive Helium-Neon laser source which has a good coherence behavior. However, coherence break-down through the beat of multiple longitudinal modes and the limited detector carrier-to-noise-ratio (CNR) at a measurement laser power of 1 mW have prevented a wide use of LDV in remote sensing applications. Such applications in civil engineering are bridges, towers or wind turbines. The lower photon energy of IR light at 1550 nm wavelength increases the CNR by a factor 2.4. This helps especially in the condition where the carrier power decreases below the FM threshold. We have designed a heterodyne interferometer which allows the shot noise limited detection at 1550 nm wavelength close to the theoretical possible CNR. We present calculations of the fundamental noise contributions in interferometric light detection for a comparison of the achievable CNR between common HeNe vibrometers and IR vibrometers. The calculations are backed by measurements that show the devices working close to the theoretical limits. The achievable noise level of the demodulated velocity signal is shown in dependence from the standoff distance. Our novel heterodyne interferometer has been transferred to the Polytec product RSV-150. An application example of this new sensor will be demonstrated.

The sections in this article are Introduction The Andrussow Process History Fundamentals Production of Liquid Hydrocyanic Acid Pressure Variant Oxygen Variant Ammonia Recycling Reactor and Catalyst The BMA Process Overview Development of the Catalyst Development of the BMA Tubes Reactor Design Mechanism and Kinetics of HCN formation in the BMA and Andrussow Processes Kinetics and Mechanism of the BMA Process Thermodynamic Context HCN and N2 Formation Coke Formation On the Role of Gas-Phase Reactions Catalytically Active Centers Kinetics and Mechanism of the Andrussow Process Thermodynamic Relationships HCN Formation HCN Hydrolysis Catalytically Active Centers Final Remarks Keywords: shawinigan process; Andrussow process; BMA process; reactor design and development; thermodynamics; high temperatures catalysis

This work introduces a general framework for the global optimization of arbitrary single- and multi-objective optimization tasks. The framework covers the industrial demand on a user-friendly toolkit uniting arbitrary optimizations in one graphical user interface. The framework includes a stand-alone solver communicating over a free programmable interface with one or multiple instances of any simulation tool. The functionality of the framework is shown by two highly differing case studies. The first concerns the determination of intrinsic kinetics, carried out at our industrial partners the Evonik Degussa GmbH and Evonik Oxeno GmbH. The second addresses the multi-objective mixed-integer dynamic optimization of a middle vessel batch distillation including the startup. In both case studies the high flexibility of the framework, its easy setup and its robust optimization capabilities will be shown.

The transcription factor of the cyclic AMP receptor protein/FNR family, NtcA, and the P II signaling protein play central roles in global nitrogen control in cyanobacteria. A dependence on P II for NtcA-regulated transcription, however, has not been observed. In the present investigation, we examined alterations in gene expression following nitrogen deprivation in Synechococcus elongatus strain PCC 7942 and specifically the roles of NtcA and P II . Global changes in de novo protein synthesis following combined-nitrogen deprivation were visualized by in vivo [ 35 S]methionine labeling and two-dimensional polyacrylamide gel electrophoresis analysis. Nearly all proteins whose synthesis responded specifically to combined-nitrogen deprivation in wild-type cells of S. elongatus failed to respond in P II - and NtcA-deficient mutants. One of the proteins whose synthesis was down-regulated in a P II - and NtcA-dependent manner was RbcS, the small subunit of RubisCO. Quantification of its mRNA revealed that the abundance of the rbcLS transcript following combined-nitrogen deprivation rapidly declined in wild-type cells but not in P II and NtcA mutant cells. To investigate further the relationship between P II and NtcA, fusions of the promotorless luxAB reporter genes to the NtcA-regulated glnB gene were constructed and these constructs were used to transform wild-type cells and P II − and NtcA − mutants. Determination of bioluminescence under different growth conditions showed that NtcA represses gene expression in the presence of ammonium in a P II -independent manner. By contrast, NtcA-dependent activation of glnB expression following combined-nitrogen deprivation was impaired in the absence of P II . Together, these results suggest that under conditions of combined-nitrogen deprivation, the regulation of NtcA-dependent gene expression requires the P II signal transduction protein.

Cells of the non-diazotrophic cyanobacteriumSynechococcus sp. strain PCC 7942 acclimate to nitrogen deprivation by differentiating into non-pigmented resting cells, which are able to survive prolonged periods of starvation. In this study, the physiological properties of the long-term nitrogen-starved cells are investigated in an attempt to elucidate the mechanisms of maintenance of viability. Preservation of energetic homeostasis is based on a low level of residual photosynthesis; activities of photosystem II and photosystem I were approximately 0.1% of activities of vegetatively growing cells. The low levels of photosystem I activity were measured by a novel colorimetric assay developed from the activity staining of ferredoxin:NADP+ oxidoreductase. Photosystem II reaction centers, as determined by chlorophyll fluorescence measurements, exhibited normal properties, although the efficiency of light harvesting was significantly reduced compared with that of control cells. Long-term chlorotic cells carried out protein synthesis at a very low, but detectable level, as revealed by in vivo [35S]methionine labeling and two-dimensional gel electrophoresis. In conjunction with the very low levels of total cellular protein contents, this implies a continuous protein turnover during chlorosis. Synthesis of components of the photosynthetic apparatus could be detected, whereas factors of the translational machinery were stringently down-regulated. Beyond the massive loss of protein during acclimation to nitrogen deprivation, two proteins that were identified as SomA and SomB accumulated due to an induced expression following nitrogen reduction.

We report the cloning and sequencing of the glnN gene encoding a class III glutamine synthetase from the cyanobacterium Synechococcus strain PCC 7942. Mapping of the transcriptional start site revealed a DNA sequence in the promoter region that resembles an imperfect NtcA binding motif. Expression of glnN is impaired in NtcA- and P II -deficient mutants. The only parameter which was negatively affected in the glnN mutant compared to the wild type was the recovery rate of prolonged nitrogen-starved cells with low concentrations of combined nitrogen.

The nondiazotrophic cyanobacterium Synechococcus sp. strain PCC 7942 responds to nitrogen deprivation by differentiating into nonpigmented resting cells able to survive prolonged periods of starvation. The degradation of photosynthetic pigments, termed chlorosis, proceeds in an ordered manner in which the light-harvesting phycobiliproteins are degraded prior to chlorophyll. Here, we show that the function of the global transcription activator of nitrogen-regulated genes, NtcA, is required for the sequential pigment degradation and cell survival. The P(II) protein, known to signal the nitrogen status of the cells, is most probably not involved in the perception of the nitrogen-starvation-specific signal since in a mutant lacking P(II), chlorosis proceeded in the same manner as in the wild type. Inhibition of glutamine synthetase with l-methionine sulfoximine led to a rapid decrease of apc mRNA and to an increase of nblA mRNA levels, which is characteristic for nitrogen deprivation, suggesting that nitrogen starvation is sensed by a metabolic signal connected to glutamine synthetase activity. However, l-methionine sulfoximine treatment did not induce phycobiliprotein degradation, but led to an immediate cessation of this proteolytic process after its induction by nitrogen deprivation. This suggests that the proteolytic activity elicited by the expression of nblA has to be supported by glutamine synthetase activity.

Neben der Herausforderung gesattigter Markte, der Internationalisierung, Technologiedynamik und des Wertewandels stehen in zunehmendem Mase okologieorientierte Fragestellungen im Mittelpunkt der Diskussion in Wissenschaft und Untemehmenspraxis. Verscharfte gesetzliche Umweltschutzanforderungen und die wachsende Sensibilisierung der Bevolkerung in Hinblick auf umweltschonende Produkte, Dienstleistungen und leistungserstellende Prozesse begrunden dabei die Entwicklung und Implementierung von Umweltschutzkonzepten.

Bio based platform chemicals can be provided through lignin, especially aromatic compounds. Lignin is a 3D- macromolecule which contains phenolic structures and a variety of functional groups. The ecological point of view of the exchange of crude oil production strains with biomass like lignin should be held high. Nevertheless, on the one hand lignin is a natural molecule which is built to resists environmental influences, so the use as a starting material held a lot of challenges. On the other hand, lignin could be a source of bifunctional molecules, like the monocyclic compounds catechol or guaiacol, which can be used as monomeric compounds for polymers. However, no method for aromatics production from lignin has been established by now.Hence, the focus of the presented work is to get a better knowledge of lignin as a starting material to produce chemicals. Therefore, the different influences of temperature and reaction times, the reaction pathways and the therefore necessary analytics need to be understood. But lignin brings a lot of challenges with it. The first is that every lignin has a different composition, depending on the wood source and the degradation method applied to gain the lignin which has a significant influence on the lignin structure. And with this, a lot of changes come e.g. in the handling of the biomass. To liquefy lignin towards high functional molecules, hydrothermal conditions are used. Water is already a main component of biomass and an ecological friendly solvent. It further proved to increase the yield and selectivity towards bifunctional molecules like catechol. The combination of fast hydrolysis, thermal degradation reactions, and hydrogenation drives the hydrothermal liquefaction; this gives the possibility to narrow down the product spectrum in comparison to other "dry" methods, towards a higher yield of e.g. catechols., Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 987-991

Gasification in supercritical water can be assisted with heterogeneous catalysts. Effective salt separation up stream of the catalyst is important to avoid poisoning of the catalyst and recover nutrients. Recovery of phosphorus, nitrogen and gasification of a significant portion of organic bounded carbon have been demonstrated in the pilot plant scale. A Ru/C catalyst was applied to catalyze the formation of CH4 which should be the primary gasification product. On top of the catalyst a layer of ZnO as sulfur adsorbent was used to protect the catalyst from deactivation. As feedstock for the process glycerol, ethanol and digestate sludge were applied., Proceedings of the 24th European Biomass Conference and Exhibition, 6-9 June 2016, Amsterdam, The Netherlands, pp. 1062-1066

The process of gasification of organic substances in supercritical water is an effective method for the energetic utilization of wet residual biomass. Biomass contains also inorganic plant components like Phosphorous, Sulphur and Nitrogen salts. Reuse of these components is essential in order to save the limited natural resources and energy. On the other hand, inorganic salts precipitate under the conditions of supercritical water and cause plugging and corrosion of different components. In the present work, a new procedure to separate inorganic salts during the gasification process is applied to spent grains slurries. Reaction conditions were temperature up to 660°C and a pressure of 28 MPa. Salt separation occurred at 350-450 °C in a lab-scale plant. Dry matter content of the feed slurry was 12 wt%, residence time in the reactor about 5 min. KHCO3, a known homogenous catalyst, was added to the feed slurry., Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 338-343

Gas fermentation using anaerobic bacteria as a biocatalyst is an attractive biotechnological process for the sustainable conversion of synthesis gas for the production of green fuels and chemicals. A known bottleneck of syngas fermentation are low gas-liquid mass transfer rates, caused by the low solubility of syngas components in the fermentation liquid. This work presents the results of an experimental study on syngas fermentation at elevated pressure, which can be employed to enhance gas solubility according to Henry’s Law. Gas fermentation with a process pressure up to 7 bar were performed in a high-pressure stirred-tank reactor. Clostridium ljungdahlii was used as biocatalyst, converting a mixture of H2, CO and CO2 to acetic acid, ethanol and formic acid. Gas consumption, cell growth, and product concentration are determined during fermentation. Results show a positive effect of a moderate pressure increase on cell growth and acetate productivity. The highest cell density (1.05 g L-1) as well as highest acetate concentration (16.9 g L-1) are observed at a pressure of 4 bar. Gas conversion rates are increased, with CO conversion reaching nearly 99 %. A further direct pressure increase up to 7 bar leads to a decrease in fermentation stability., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 1255-1261