scholarly journals Evaluation of the Potential for Dissolved Oxygen Ingress into Deep Sedimentary Basins during a Glaciation Event

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Sergio A. Bea ◽  
Danyang Su ◽  
K. Ulrich Mayer ◽  
Kerry T. B. MacQuarrie
Keyword(s):  
Dissolved Oxygen ◽  
Reactive Transport ◽  
Large Scale ◽  
Sedimentary Basins ◽  
Mineral Dissolution ◽  
Depth Of Penetration ◽  
Glacial Meltwater ◽  
Oxidation Rates ◽  
High Concentrations ◽  
Oxygen Ingress

Geochemical conditions in intracratonic sedimentary basins are currently reducing, even at relatively shallow depths. However, during glaciation-deglaciation events, glacial meltwater production may result in enhanced recharge (Bea et al., 2011; and Bea et al., 2016) potentially having high concentrations of dissolved oxygen (O2). In this study, the reactive transport code Par-MIN3P-THCm was used to perform an informed, illustrative set of simulations assessing the depth of penetration of low salinity, O2-rich, subglacial recharge. Simulation results indicate that the large-scale basin hydrostratigraphy, in combination with the presence of dense brines at depth, results in low groundwater velocities during glacial meltwater infiltration, restricting the vertical ingress of dilute recharge waters. Furthermore, several geochemical attenuation mechanisms exist for O2, which is consumed by reactions with reduced mineral phases and solid organic matter (SOM). The modeling showed that effective oxidative mineral dissolution rates and SOM oxidation rates between 5 × 10−15 and 6 × 10−13 mol dm−3 bulk s−1 were sufficient to restrict the depth of O2 ingress to less than 200 m. These effective rates are low and thus conservative, in comparison to rates reported in the literature. Additional simulations with more realistic, yet still conservative, parameters reaffirm the limited ability for O2 to penetrate into sedimentary basin rocks during a glaciation-deglaciation event.

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

scholarly journals Glucose-Limited Fed-Batch Cultivation Strategy to Mimic Large-Scale Effects in Escherichia coli Linked to Accumulation of Non-Canonical Branched-Chain Amino Acids by Combination of Pyruvate Pulses and Dissolved Oxygen Limitation

2021 ◽  
Vol 9 (6) ◽  
pp. 1110
Author(s):  
Ángel Córcoles García ◽  
Peter Hauptmann ◽  
Peter Neubauer
Keyword(s):  
Amino Acids ◽  
Dissolved Oxygen ◽  
Large Scale ◽  
Scale Effects ◽  
Branched Chain Amino Acids ◽  
Oxygen Limitation ◽  
Fed Batch ◽  
Fermentation Products ◽  
Cultivation Strategy ◽  
Branched Chain

Insufficient mixing in large-scale bioreactors provokes gradient zones of substrate, dissolved oxygen (DO), pH, and other parameters. E. coli responds to a high glucose, low oxygen feeding zone with the accumulation of mixed acid fermentation products, especially formate, but also with the synthesis of non-canonical amino acids, such as norvaline, norleucine and β-methylnorleucine. These amino acids can be mis-incorporated into recombinant products, which causes a problem for pharmaceutical production whose solution is not trivial. While these effects can also be observed in scale down bioreactor systems, these are challenging to operate. Especially the high-throughput screening of clone libraries is not easy, as fed-batch cultivations would need to be controlled via repeated glucose pulses with simultaneous oxygen limitation, as has been demonstrated in well controlled robotic systems. Here we show that not only glucose pulses in combination with oxygen limitation can provoke the synthesis of these non-canonical branched-chain amino acids (ncBCAA), but also that pyruvate pulses produce the same effect. Therefore, we combined the enzyme-based glucose delivery method Enbase® in a PALL24 mini-bioreactor system and combined repeated pyruvate pulses with simultaneous reduction of the aeration rate. These cultivation conditions produced an increase in the non-canonical branched chain amino acids norvaline and norleucine in both the intracellular soluble protein and inclusion body fractions with mini-proinsulin as an example product, and this effect was verified in a 15 L stirred tank bioreactor (STR). To our opinion this cultivation strategy is easy to apply for the screening of strain libraries under standard laboratory conditions if no complex robotic and well controlled parallel cultivation devices are available.

Two-dimensional elastic pseudo-spectral modeling of wide-aperture seismic array data with application to the Wichita Uplift-Anadarko Basin region of southwestern Oklahoma

1990 ◽  
Vol 80 (6A) ◽  
pp. 1677-1695 ◽  
Author(s):  
Ik Bum Kang ◽  
George A. McMechan
Keyword(s):  
Large Scale ◽  
Deep Structure ◽  
Sedimentary Basins ◽  
P Wave ◽  
Two Dimensional ◽  
Anadarko Basin ◽  
Near Surface ◽  
University Of Texas ◽  
Wide Aperture ◽  
The University

Abstract Full wave field modeling of wide-aperture data is performed with a pseudospectral implementation of the elastic wave equation. This approach naturally produces three-component stress and two-component particle displacement, velocity, and acceleration seismograms for compressional, shear, and Rayleigh waves. It also has distinct advantages in terms of computational requirements over finite-differencing when data from large-scale structures are to be modeled at high frequencies. The algorithm is applied to iterative two-dimensional modeling of seismograms from a survey performed in 1985 by The University of Texas at El Paso and The University of Texas at Dallas across the Anadarko basin and the Wichita Mountains in southwestern Oklahoma. The results provide an independent look at details of near-surface structure and reflector configurations. Near-surface (<3 km deep) structure and scattering effects account for a large percentage (>70 per cent) of the energy in the observed seismograms. The interpretation of the data is consistent with the results of previous studies of these data, but provides considerably more detail. Overall, the P-wave velocities in the Wichita Uplift are more typical of the middle crust than the upper crust (5.3 to 7.1 km/sec). At the surface, the uplift is either exposed as weathered outcrop (5.0 to 5.3 km/sec) or is overlain with sediments of up to 0.4 km in thickness, ranging in velocity from 2.7 to 3.4 km/sec, generally increasing with depth. The core of the uplift is relatively seismically transparent. A very clear, coherent reflection is observed from the Mountain View fault, which dips at ≈40° to the southwest, to at least 12 km depth. Velocities in the Anadarko Basin are typical of sedimentary basins; there is a general increase from ≈2.7 km/sec at the surface to ≈5.9 km/sec at ≈16 km depth, with discontinuous reflections at depths of ≈8, 10, 12, and 16 km.

scholarly journals COMPORTAMIENTO DE TORRE DE LAVADO A NIVEL DE ESCALA PARA LA REMOCIÓN DE H2S DE UN REACTOR ANAEROBICO DE FLUJO ASCENDENTE

2018 ◽  
Vol 27 (1) ◽  
pp. 85
Author(s):  
José A. Acaro R ◽  
Jeannie L. Quispe E. ◽  
Mali I. Salas D.
Keyword(s):  
Hydrogen Sulfide ◽  
Dissolved Oxygen ◽  
Coming Out ◽  
Packed Bed ◽  
Uasb Reactor ◽  
Sulfate Concentration ◽  
Hydrogen Sulfide Removal ◽  
Palabras Clave ◽  
Wet Scrubber ◽  
High Concentrations

Nuestro equipo en esta oportunidad hizo una simulación de una torre de lavado, la cual la aplicamos en el reactor UASB, a manera de escala construimos una torre de lavado compuesta por difusores, una cama de sólidos hecha de material de esponja, un tubo de acrílico y todas las conexiones que conducen el biogás con H2S. Los componentes a eliminar y/o remover fueron los gases que salen del reactor, en especial del H2S (gas odorífero y toxico que a grandes concentraciones pude llevar a la muerte y como resultado de sus reacciones con el ambiente puede causar daños en las estructuras con la cual este en contacto) mediante la oxidación con el oxígeno disuelto que proveen las microalgas presentes en el agua de la laguna terciara utilizada. Esta torre de lavado la montamos en las instalaciones de CITRAR‐UNI con el permiso del operador y vimos el comportamiento que tiene esta torre, mediante los monitoreos de oxígeno disuelto, temperatura, pH y sulfatos que realizamos durante tres semanas de monitoreo. Como resultados obtuvimos que la torre de lavado sí oxidaba y removía la contracción de H2S, ya que cuando pasaba el tiempo se consumía el oxígeno disuelto, además de esto también en el monitoreo de sulfatos pudimos observar un aumento de este parámetro es decir la torre si estaba consumiendo en H2S, y por esta razón también disminuyo el olor fétido que produce este gas. Palabras clave.- Torre de lavado, reactor UASB, remoción de sulfuro de hidrógeno. ABSTRACT The present work reports the simulation of a wet scrubber coupled to an UASB reactor. The scrubber consisted of baffles, packed bed of sponge material, an acrylic tube and all the connections necessary to bring the H2S‐ladden biogas. The purpose of the equipment is to eliminate some of the gases coming out of the reactor, through their oxidation by the dissolved oxygen provided by the microalgae present in the water from the tertiary lagoon. Hydrogen sulfide is a foul‐ smelling and toxic gas which can cause death at high concentrations, and can also cause damage to the structures with which it comes into contact. The scrubber was installed on the site of CITRAR‐UNI and the behavior of the equipment was monitored during three weeks by following the temperature, pH and the concentrations of sulfates and dissolved oxygen. The results have shown that the scrubber was effectively an oxidizing environment which was removing H2S, since the dissolved oxygen was actually consumed gradually. It was also observed that the sulfate concentration was increasing, indicating a consumption of H2S, which was also confirmed by a reduction in the odor of the gas. Keywords.- scrubber, UASB reactor, hydrogen sulfide removal .

scholarly journals Changes in Oxygen Availability during Glucose-Limited Chemostat Cultivations of Penicillium chrysogenum Lead to Rapid Metabolite, Flux and Productivity Responses

Metabolites ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 45
Author(s):  
Qi Yang ◽  
Wenli Lin ◽  
Jiawei Xu ◽  
Nan Guo ◽  
Jiachen Zhao ◽  
...  
Keyword(s):  
Steady State ◽  
Dissolved Oxygen ◽  
Penicillium Chrysogenum ◽  
Large Scale ◽  
Scale Up ◽  
Redox Status ◽  
Oxygen Availability ◽  
Industrial Scale ◽  
Cell Factory ◽  
Microbial Cell Factory

Bioreactor scale-up from the laboratory scale to the industrial scale has always been a pivotal step in bioprocess development. However, the transition of a bioeconomy from innovation to commercialization is often hampered by performance loss in titer, rate and yield. These are often ascribed to temporal variations of substrate and dissolved oxygen (for instance) in the environment, experienced by microorganisms at the industrial scale. Oscillations in dissolved oxygen (DO) concentration are not uncommon. Furthermore, these fluctuations can be exacerbated with poor mixing and mass transfer limitations, especially in fermentations with filamentous fungus as the microbial cell factory. In this work, the response of glucose-limited chemostat cultures of an industrial Penicillium chrysogenum strain to different dissolved oxygen levels was assessed under both DO shift-down (60% → 20%, 10% and 5%) and DO ramp-down (60% → 0% in 24 h) conditions. Collectively, the results revealed that the penicillin productivity decreased as the DO level dropped down below 20%, while the byproducts, e.g., 6-oxopiperidine-2-carboxylic acid (OPC) and 6-aminopenicillanic acid (6APA), accumulated. Following DO ramp-down, penicillin productivity under DO shift-up experiments returned to its maximum value in 60 h when the DO was reset to 60%. The result showed that a higher cytosolic redox status, indicated by NADH/NAD+, was observed in the presence of insufficient oxygen supply. Consistent with this, flux balance analysis indicated that the flux through the glyoxylate shunt was increased by a factor of 50 at a DO value of 5% compared to the reference control, favoring the maintenance of redox status. Interestingly, it was observed that, in comparison with the reference control, the penicillin productivity was reduced by 25% at a DO value of 5% under steady state conditions. Only a 14% reduction in penicillin productivity was observed as the DO level was ramped down to 0. Furthermore, intracellular levels of amino acids were less sensitive to DO levels at DO shift-down relative to DO ramp-down conditions; this difference could be caused by different timescales between turnover rates of amino acid pools (tens of seconds to minutes) and DO switches (hours to days at steady state and minutes to hours at ramp-down). In summary, this study showed that changes in oxygen availability can lead to rapid metabolite, flux and productivity responses, and dynamic DO perturbations could provide insight into understanding of metabolic responses in large-scale bioreactors.

scholarly journals Influence of Storage Period on the Geochemical Evolution of a Compressed Energy Storage System

2021 ◽  
Vol 3 ◽  
Author(s):  
Chidera O. Iloejesi ◽  
Lauren E. Beckingham
Keyword(s):  
Energy Storage ◽  
Reactive Transport ◽  
Storage System ◽  
Storage Period ◽  
Energy Storage System ◽  
Storage Conditions ◽  
Mineral Dissolution ◽  
Geochemical Evolution ◽  
Operational Life ◽  
Storage Zone

Subsurface porous aquifers are being considered for use as reservoirs for compressed energy storage of renewable energy. In these systems, a gas is injected during times in which production exceeds demand and extracted for energy generation during periods of peak demand or scarcity in production. Current operational subsurface energy facilities use salt caverns for storage and air as the working gas. CO2 is potentially a more favorable choice of working gas where under storage conditions CO2 has high compressibility which can improve operational efficiency. However, the interaction of CO2 and brine at the boundary of the storage zone can produce a chemically active fluid which can result in mineral dissolution and precipitation reactions and alter the properties of the storage zone. This study seeks to understand the geochemical implications of utilization of CO2 as a working gas during injection, storage and extraction flow cycles. Here, reactive transport simulations are developed based on 7 h of injection, 11 h of withdrawal and 6 h of reservoir closure, corresponding to the schedule of the Pittsfield field test, for 15 years of operational life span to assess the geochemical evolution of the reservoir. The evolution in the storage system is compared to a continuously cyclic system of 12 h injection and extraction. The result of the study on operational schedule show that mineral reactivity occurs at the inlet of the domain. Furthermore, the porosity of the inner domain is preserved during the cycling of CO2 acidified brine for both systems.

Correlation between Chlorophyll-a Concentration and Environmental Factors in Jihongtan Reservoir

2011 ◽  
Vol 356-360 ◽  
pp. 959-962
Author(s):  
Ji Ping Ma ◽  
Cui Jie Rui ◽  
Jian Hua Ge ◽  
Yu Hua Liu ◽  
Zhi Wen Song ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Statistical Method ◽  
Chlorophyll A ◽  
Potassium Permanganate ◽  
Total Nitrogen ◽  
Average Concentration ◽  
Low Concentrations ◽  
High Concentrations

Based on the Jihogntan reservoir’s monitoring data from 2006 to 2009, eutrophication of Jihongtan reservoir was assessed. The result showed that the nutrition level of the Jihongtan reservoir was middle in recent years. The average concentration of chlorophyll-a(Chla) was higher in summer and autumn than in spring and winter. The correlation between concentration of Chla and some environmental factors was studied by statistical method, and seasonal variation of Chla and the extent of eutrophication were also analyzed. The results showed that the correlations between Chla and total nitrogen(TN), dissolved oxygen(DO) and transparency were significantly negative, and that between Chla and total phosphorus(TP), temperature(T) and potassium permanganate index(COD Mn) were significantly positive. The growth of phytoplankton was promoted by TP and TN at low concentrations, and inhibited by TN at high concentrations.

Latent disciplinal clashes concerning the batch dissolution of minerals, and their wider implications

2018 ◽  
Vol 15 (2) ◽  
pp. 113 ◽  
Author(s):  
Victor W. Truesdale ◽  
Jim Greenwood
Keyword(s):  
Large Scale ◽  
Dissolution Kinetics ◽  
Mineral Dissolution ◽  
Atomic Scale ◽  
Rate Equations ◽  
Silicate Mineral ◽  
Waste Products ◽  
Calcite Dissolution ◽  
Macro Scale ◽  
Made In

Environmental contextMineral dissolution kinetics are important to understand natural processes including those increasingly used to store waste carbon dioxide and highly radio-active nuclides, and those involved in the amelioration of climate change and sea-level rise. We highlight a mistake made in the fundamental science that has retarded progress in the field for over 40 years. Its removal suggests improved ways to approach dissolution studies. AbstractMineral dissolution kinetics are fundamental to biogeochemistry, and to the application of science to reduce the deleterious effects of humanity’s waste products, e.g. CO2 and radio-nuclides. However, a mistake made in the selection of the rate equation appropriate for use at the macro-scale of the aquatic environment has stymied growth in major aspects of the subject for some 40 years. This paper identifies the mistake, shows how it represents a latent disciplinal clash between two rate equations, and explores the misunderstandings that resulted from it. The paper also briefly explores other disciplinal clashes. Using the example of calcite dissolution, the paper also shows how the phenomenon of ‘non-ideal’ dissolution, which is prevalent in alumino-silicate mineral dissolution, as well as with calcite, has obscured the clash. The paper provides new information on plausible mechanisms, the absence of which has contributed to the problem. Finally, it argues that disciplinal clashes need to be minimised so that a rigorous description of dissolution at the large scale can be matched to findings at the atomic, or near-atomic, scale.

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