PRESERVATION OF FOSSIL MICROBES AND BIOFILM IN CAVE POOL CARBONATES AND COMPARISON TO OTHER MICROBIAL CARBONATE ENVIRONMENTS

Palaios ◽  
2016 ◽  
Vol 31 (4) ◽  
pp. 177-189 ◽  
Author(s):  
LESLIE A. MELIM ◽  
DIANA E. NORTHUP ◽  
PENELOPE J. BOSTON ◽  
MICHAEL N. SPILDE
Keyword(s):  
Organic Material ◽  
Elevated Temperatures ◽  
Hot Spring ◽  
Cold Seep ◽  
Alternative Mode ◽  
Photolytic Degradation ◽  
Microbial Carbonate ◽  
Edx Analyses ◽  
Uniform Diameter

Abstract Fossil microbes are generally preserved by authigenic minerals, including silica, apatite, iron minerals, clays, and carbonates. An alternative mode of preservation by entombment in calcite, without replacement, has been identified in carbonate cave pool microbialites that were etched and examined in the scanning electron microscope (SEM). Features identified include filaments, threads, and films that show excess carbon in energy dispersive X-ray (EDX) analyses, suggesting preservation of organic matter. Filaments are single smooth or reticulated strands with curving string-like morphology, often hollow, and with a uniform diameter of 0.5 to 1.0 μm. Threads, in contrast, are variable thickness, from several microns down to 0.1 μm, always solid, and commonly branch. Films are thin (< 1 μm) drapes associated with threads. Filaments are interpreted as microbial filaments, while threads and films are interpreted as preserved extracellular polymeric substance (EPS). In addition, microbial filaments and EPS are only revealed via acid etching, suggesting preservation of organic material by entombment, not by replacement with calcite. To determine whether entombed microbes are a common feature of carbonate microbialites that form in different environmental settings, samples of hot spring travertine, caliche soil, and reef microbialite were examined. Whereas the travertine samples were barren, entombed EPS was found in the caliche soil and the reef microbialite; the latter also contained a few entombed filaments. In addition, entombed microbial material has been reported from carbonate cold seep deposits. Such findings indicate that entombment of microbes and EPS in carbonates is not restricted to cave settings, but is more widespread than previously reported. Possible causes for the lack of preservation in travertines include rapid degradation of microbial material either by sunlight due to photolytic degradation, aerobic microbial degradation, detritivore consumption, or elevated temperatures. Rapid carbonate precipitation is ruled out as, somewhat surprisingly, preservation is better in slower growing cave carbonates than in rapidly growing travertines. Potential long-term preservation of organic material entombed in carbonate has implications for the characterization of fossil microbial communities using molecular biomarkers and the search for life on other planets.

scholarly journals CO Detection Investigation at High Temperature by SiC MISFET Metal/Oxide Gas Sensors

Proceedings ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 41
Author(s):  
Lida Khajavizadeh ◽  
Anita Lloyd Spetz ◽  
Mike Andersson
Keyword(s):  
High Temperature ◽  
Gas Sensors ◽  
Elevated Temperatures ◽  
Long Term Stability ◽  
Stability Performance ◽  
Catalytic Metal ◽  
Co Detection ◽  
Effect Transistor ◽  
Metal Oxide Gas Sensors

In order to investigate the necessary device improvements for high-temperature CO sensing with SiC metal insulator semiconductor field effect transistor (MISFET)-based chemical gas sensors, devices employing, as the gas-sensitive gate contact, a film of co-deposited Pt/Al2O3 instead of the commonly used catalytic metal-based contacts were fabricated and characterized for CO detection at elevated temperatures and different CO and O2 levels. It can be concluded that the sensing mechanism at elevated temperatures correlates with oxygen removal from the sensor surface rather than the surface CO coverage as observed at lower temperatures. The long-term stability performance was also shown to be improved compared to that of previously studied devices.

scholarly journals The Long-Term Impact of Different Offline Population Inclusion Strategies in Probability-Based Online Panels: Evidence From the German Internet Panel and the GESIS Panel

2021 ◽  
pp. 089443932098413
Author(s):  
Carina Cornesse ◽  
Ines Schaurer
Keyword(s):  
Survey Data ◽  
Positive Impact ◽  
Alternative Mode ◽  
Mail Surveys ◽  
Internet Users ◽  
Online Panels ◽  
Long Term Impact ◽  
The Impact ◽  
Postal Mail

While online panels offer numerous advantages, they are often criticized for excluding the offline population. Therefore, some probability-based online panels have developed offline population inclusion strategies. Two dominant approaches prevail: providing internet equipment and offering an alternative survey participation mode. We investigate the impact of these approaches on two probability-based online panels in Germany: the German Internet Panel, which provides members of the offline population with internet equipment, and the GESIS Panel, which offers members of the offline population to participate via postal mail surveys. In addition, we explore the impact of offering an alternative mode only to non-internet users versus also offering the alternative mode to internet users who are unwilling to provide survey data online. Albeit lower recruitment and/or panel wave participation probabilities among offliners than onliners, we find that including the offline population has a positive long-term impact on sample accuracy in both panels. In the GESIS Panel, the positive impact is particularly strong when offering the alternative participation mode to non-internet users and internet users who are unwilling to provide survey data online.

Technology Focus: Wellbore Tubulars (July 2021)

2021 ◽  
Vol 73 (07) ◽  
pp. 50-50
Author(s):  
Robello Samuel
Keyword(s):  
Geothermal Energy ◽  
Elevated Temperatures ◽  
Clean Energy ◽  
Well Integrity ◽  
The Future ◽  
Geothermal Wells ◽  
Abandoned Wells ◽  
Thermal Simulations ◽  
Technology Focus

How we think about the future of the pipe industry must evolve. How must tubular design and manufacturing change as we transition to clean energy? Geothermal energy is an area that needs attention and, further, needs very specific attention on tubulars. Tubulars are an important component in the construction of geothermal wells, and we must align our requirements for geothermal energy. Some of the main challenges encountered in geothermal wells are corrosion and scaling. Moreover, temperature becomes a major consideration for tubulars, even more so with the temperature excursion during geothermal production. Perhaps the critical aspect in the design of the geothermal wells involves casing selection and design. Beyond manufacturing casing pipes to withstand these problems, considering the manufacturing of other components, such as connections, float collars, and float shoes, also is essential. Thermal expansion and thermal excursion of casings are well-integrity concerns; thus, casing design is important for long-term sustainability of geothermal wells. Apart from thermal simulations, guidelines and software are needed to undergird the designs to withstand not only temperature excursions but also thermomechanical and thermochemical loadings. Engineered nonmetallic casings also provide an alternative solution because they provide the desired strength and corrosion resistance in addition to meeting the goals of sustainability. Undoubtedly, the future of the tubular industry is going to be revitalized. The question now is how we can retrofit existing abandoned wells for this purpose. Recommended additional reading at OnePetro: www.onepetro.org. SPE 199570 - Special Considerations for Well-Tubular Design at Elevated Temperatures by Gang Tao, C-FER Technologies, et al.

Rational Design of Organic Electro-Optic Materials

2001 ◽  
Vol 708 ◽  
Author(s):  
Alex Jen ◽  
Robert Neilsen ◽  
Bruce Robinson ◽  
William H. Steier ◽  
Larry Dalton
Keyword(s):  
Wavelength Division Multiplexing ◽  
Material Properties ◽  
Electrostatic Interactions ◽  
Rational Design ◽  
Elevated Temperatures ◽  
Optical Loss ◽  
Quality Factors ◽  
Electro Optic ◽  
Lattice Hardening

ABSTRACTA number of material properties must be optimized before organic electro-optic materials can be used for practical device applications. These include electro-optic activity, optical transparency, and stability including both thermal and photochemical stability. Exploiting an improved understanding of the structure/function relationships, we have recently prepared materials exhibiting electro-optic coefficients of greater than 50 pm/V and optical loss values of less than 0.7 dB/cm at the telecommunication wavelengths of 1.3 and 1.55 microns. When oxygen is excluded to a reasonable extent, long-term photostability to optical power levels of 20 mW has been observed. Photostability is further improved by addition of scavengers and by lattice hardening. Long-term (greater than 1000 hours) thermal stability of poling-induced electro-optic activity is also observed at elevated temperatures (greater than 80°C) when appropriate lattice hardening is used. The successful improvement of organic electro-optic materials rests upon (1) attention to the design of chromophore structure including design to inhibit unwanted intermolecular electrostatic interactions and to improve chromophore instability and (2) attention to processing conditions including those involved in spin casting, electric field poling, and lattice hardening. A particularly attractive new direction has been the exploitation of dendrimer structures and particularly of multi-chromophore containing dendrimer structures. This approach has permitted the simultaneous improvement of all material properties. Development of new materials has facilitated the fabrication of a number of prototype devices and most recently has permitted investigation of the incorporation of electro-optic materials into photonic bandgap and microresonator structures. The latter are relevant to active wavelength division multiplexing (WDM). Significant quality factors (greater than 10,000) have been realized for such devices permitting wavelength discrimination at telecommunication wavelengths of 0.01 nm.

scholarly journals High–flux Composite PTMSP Membranes with Long–term Stable Characteristics at Elevated Temperatures and Pressures

2012 ◽  
Vol 44 ◽  
pp. 782-783 ◽  
Author(s):  
G. Dibrov ◽  
E. Novitskii ◽  
V. Vasilevskii ◽  
S. Bazhenov ◽  
V. Volkov
Keyword(s):  
Elevated Temperatures ◽  
High Flux

scholarly journals The long-term variations of rare earth element contents in Tamagawa hot spring waters, Akita Prefecture, Japan.

2002 ◽  
Vol 63 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Tetsuya SANADA ◽  
Nobuki TAKAMATSU ◽  
Yuzo YOSHIIKE ◽  
Masayuki IMAHASHI ◽  
Hideo HIGUCHI
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Hot Spring ◽  
Akita Prefecture ◽  
Element Contents ◽  
Long Term Variations

Long-Term Stability of Aluminum Oxide Based Surface Passivation Schemes Under Illumination at Elevated Temperatures

2017 ◽  
Vol 7 (5) ◽  
pp. 1197-1202 ◽  
Author(s):  
Tim Niewelt ◽  
Wolfram Kwapil ◽  
Marisa Selinger ◽  
Armin Richter ◽  
Martin C. Schubert
Keyword(s):  
Aluminum Oxide ◽  
Elevated Temperatures ◽  
Surface Passivation ◽  
Term Stability ◽  
Long Term Stability

Analysing the relationship of CO2 and O2 concentrations and flux patterns in forest soils

2021 ◽  
Author(s):  
Valentin Gartiser ◽  
Verena Lang ◽  
Martin Maier
Keyword(s):  
Diffusion Coefficient ◽  
Organic Material ◽  
West Germany ◽  
Atmospheric Environment ◽  
Concentration Data ◽  
Forest Sites ◽  
Production And Consumption ◽  
Different Depths ◽  
Relationship Of

&lt;p&gt;Soils act as bioreactors for the production and consumption of different gases. CO&lt;sub&gt;2&lt;/sub&gt; is usually produced in soils due to the oxidation of organic material. Under aerobic conditions, this production is coupled to a consumption of O&lt;sub&gt;2&lt;/sub&gt; resulting in concentration profiles that increase with depth for CO&lt;sub&gt;2&lt;/sub&gt; and decrease for O&lt;sub&gt;2&lt;/sub&gt;. Depending on the organic material present, the exchange of O&lt;sub&gt;2&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt; is approximately equimolar in well aerated soils. This can be deduced from vertical gradients of both gases which should reflect the ratio of their diffusion coefficient (Massmann 1998). The ratio between the CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; flux is often called the respiratory coefficient. However, certain soil types or conditions may invoke anaerobe processes that may lead to a decoupling of CO&lt;sub&gt;2&lt;/sub&gt; production and O&lt;sub&gt;2&lt;/sub&gt; consumption. Such a decoupling can also result from oxidation of minerals or dissolution and relocation of carbonates.&lt;/p&gt;&lt;p&gt;Here we present long-term data of soil CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; concentrations from forest sites in South West Germany. Gas samples were collected passively starting 1998 until now using permanently installed gas wells at different depths. The samples were then analysed using gas chromatography for CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; (and additionally N&lt;sub&gt;2&lt;/sub&gt;, Ar, N&lt;sub&gt;2&lt;/sub&gt;O, CH&lt;sub&gt;4&lt;/sub&gt;, and C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;4&lt;/sub&gt;).&lt;/p&gt;&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; fluxes were calculated using the gradient approach (Maier et al 2020). At sites with well aerated soils, the observed CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; fluxes followed a clear linear relationship, with high effluxes of CO&lt;sub&gt;2&lt;/sub&gt; corresponding to high influxes of O&lt;sub&gt;2&lt;/sub&gt;. The exchange was furthermore approximately equimolar with the calculated fluxes following a -1:1 trend.&lt;/p&gt;&lt;p&gt;We will compare these data from well aerated soils to concentration data of CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; from less well-aerated soils with temporally suboxic conditions to further analyse the respiratory coefficient under oxygen limited conditions. Furthermore, diffusion-coefficient-normalised gradients are calculated to obtain information about the stoichiometry of the production and consumption patterns involved.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Literature:&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Maier M, Gartiser V, Schengel A, Lang V. Long Term Soil Gas Monitoring as Tool to Understand Soil Processes. Applied Sciences. 2020; 10(23):8653.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Massman, W J. A review of the molecular diffusivities of H&lt;sub&gt;2&lt;/sub&gt;O, CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt;, CO, O&lt;sub&gt;3&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, NH&lt;sub&gt;3&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O, NO, and NO&lt;sub&gt;2&lt;/sub&gt; in air, O&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt; near STP. Atmospheric Environment 1998; 32(6), 1111&amp;#8211;1127&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Nucleic acid cleavage with a hyperthermophilic Cas9 from an uncultured Ignavibacterium

2019 ◽  
Vol 116 (46) ◽  
pp. 23100-23105 ◽  
Author(s):  
Stephanie Tzouanas Schmidt ◽  
Feiqiao Brian Yu ◽  
Paul C. Blainey ◽  
Andrew P. May ◽  
Stephen R. Quake
Keyword(s):  
Dna Cleavage ◽  
Elevated Temperatures ◽  
Hot Spring ◽  
Metagenomic Sequencing ◽  
Rna Seq ◽  
Bacterial Rna ◽  
Acid Cleavage ◽  
Cas9 Protein ◽  
Ribosomal Rrna

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) systems have been effectively harnessed to engineer the genomes of organisms from across the tree of life. Nearly all currently characterized Cas9 proteins are derived from mesophilic bacteria, and canonical Cas9 systems are challenged by applications requiring enhanced stability or elevated temperatures. We discovered IgnaviCas9, a Cas9 protein from a hyperthermophilic Ignavibacterium identified through mini-metagenomic sequencing of samples from a hot spring. IgnaviCas9 is active at temperatures up to 100 °C in vitro, which enables DNA cleavage beyond the 44 °C limit of Streptococcus pyogenes Cas9 (SpyCas9) and the 70 °C limit of both Geobacillus stearothermophilus Cas9 (GeoCas9) and Geobacillus thermodenitrificans T12 Cas9 (ThermoCas9). As a potential application of this enzyme, we demonstrate that IgnaviCas9 can be used in bacterial RNA-seq library preparation to remove unwanted cDNA from 16s ribosomal rRNA without increasing the number of steps, thus underscoring the benefits provided by its exceptional thermostability in improving molecular biology and genomic workflows. IgnaviCas9 is an exciting addition to the CRISPR-Cas9 toolbox and expands its temperature range.

Long-Term Evaluation of the Bonding Strength of Composite Repairs

2012 ◽  
Author(s):  
Khalid Farrag ◽  
Kevin Stutenberg
Keyword(s):  
Shear Strength ◽  
Elevated Temperatures ◽  
Water Solution ◽  
Effect Of Temperature ◽  
Shear Tests ◽  
Composite Repair ◽  
Testing Program ◽  
Repair Systems ◽  
Composite Repairs

The long-term performance of composite repair systems depends on their structural integrity and interaction with the carrier pipe. The adhesives used in the composites are critical components that not only bond the repair to the pipe, but also bond the individual layers of the repair to one another. The durability of the inter-laminate adhesive bond is required to ensure adequate load transfer between the pipe and the composite layers over the predicted lifetime of the repair. A testing program was performed to evaluate the shear strength of the adhesives used in composite repairs. The testing program evaluated the performance of seven commercially-available composite repair systems and it consisted of short-term and long-term shear tests on the adhesives and cathodic disbondment tests on the repair systems. The long-term shear tests were performed for 10,000 hours on samples submerged in a water solution with pH value of 9 and at various loading levels at temperatures of 70°F, 105°F and 140°F. The results of the long-term tests at elevated temperatures were extrapolated to predict the shear strengths at longer durations. The 20-year shear strengths of the composites were estimated using: (a) direct extrapolation of the best-fit curves and (b) the application of the rate process procedure. The results demonstrated the significant effect of temperature on the bond strength of the composites and provided a comparative analysis to evaluate the long-term shear strength and cathodic disbondment of the composite repair systems.

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