Evidence for thermal stability of ribosomal DNA sequences in hydrothermal-vent organisms

This paper reports the results of experiments designed to investigate the relationship between thermal stability of DNA and the physical and chemical conditions experienced by various species of invertebrates, with particular reference to hydrothermal vent organisms. The major conclusion is that thermal stability correlates positively with environmental temperature within the DNA regions encoding ribosomal RNA, but not throughout the genome. Increased thermal stability (based it is supposed on an increase in G-C content) of rDNA relative to total DNA confers protection to coding sequences which would otherwise be susceptible to damage during transcription. An increase in G-C content of rDNA will lead to an increase in G-C levels in rRNA which forms a major structural component of ribosomes, thus conferring increased thermal and chemical stability to these sites of amino acid synthesis within the cell.

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Synthese und Eigenschaften von Alkyloxi-und Aryloxi-substituierten Trithiadiborolanen / Synthesis and Properties of Alkoxi and Aryloxi Substituted Trithiadiborolanes

Zeitschrift für Naturforschung B ◽

10.1515/znb-1981-1117 ◽

1981 ◽

Vol 36 (11) ◽

pp. 1444-1450 ◽

Cited By ~ 10

Author(s):

Max Schmidt ◽

Erich Sametschek

Keyword(s):

Thermal Stability ◽

Nmr Spectra ◽

Chemical Properties ◽

Physical And Chemical Properties ◽

H Nmr ◽

New Compounds ◽

Physical And Chemical ◽

Thermal Stability Of ◽

And Chemical Properties

Abstract The first examples of the hitherto unknown 1,2,4-Trithia-3,5-diborolanes with B-O-C-bonds have been synthesized and characterised. The diiodo substituted ring (2) reacts with 2,6-dimethylphenol, to form 3,5-bis-(2,6-dimethylphenyloxi)-1,2,4-trithia-3,5-di-borolane (3) and HI. 3,5-Diethoxi-1,2,4-trithia-3,5-diborolane, 5, and C2H5I are formed via the cleavage of diethylether by 2. From 2 and diisopropylether, the corresponding 3,5-diisopropyloxi-1,2,4-trithia-3,5-diborolane (6) is formed. The unsymmetrical ethers methyl-t-butylether and methylphenylether undergo reactions with 2 resulting in the formation of 3,5-dimethyloxi-1,2,4-trithia-3,5-diborolane (8) (besides t-C4H9I) and 3,5-diphenyloxi-1,2,4-trithia-3,5-diborolane (10) (besides CH3I). The thermal stability of the new compounds is increasing with increasing size of R in the -OR group and from aliphatic to aromatic R in this group. IR, Raman, 1H NMR and 11B NMR spectra of the compounds are reported as well as some physical and chemical properties.

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Occurrence and significance of folic acid

Pteridines ◽

10.1515/pteridines-2018-0017 ◽

2018 ◽

Vol 29 (1) ◽

pp. 187-195 ◽

Cited By ~ 1

Author(s):

Ewa Cieślik ◽

Iwona Cieślik

Keyword(s):

Folic Acid ◽

Glutamic Acid ◽

High Sensitivity ◽

Acid Synthesis ◽

The Body ◽

Neural Tube Closure ◽

Amino Acid Synthesis ◽

Biochemical Processes ◽

Chemical Factors ◽

Physical And Chemical

AbstractFolic acid is a naturally occurring pteridine, which was originally isolated from plants. Folic acid (pteroyl-glutamic acid) is composed of pteridine (6-methylptero), p-aminobenzoic acid (PABA) and glutamic acid. Folic acid (folacin) is a compound of major importance for the proper functioning of the human body. Its adequate supply is essential for the proper course of many biochemical processes in the body, including the process of neural tube closure in the fetus, DNA and amino acid synthesis, growth of red blood cells, and the function of the nervous system. Folic acid is a compound of a high sensitivity to physical and chemical factors, and its bioavailability is limited by interactions with multiple food components. Therefore, folate deficiency is one of the most common deficiencies. This paper presents the structure and characteristics of folic acid as a pteridine, it also discusses dietary sources of folate and the effects of its deficiency.

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Effect of Physical and Chemical Surface Treatment on the Thermal Stability of Hemp Fibers as Reinforcement in Composite Structures

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.616 ◽

2011 ◽

Vol 71-78 ◽

pp. 616-620 ◽

Cited By ~ 4

Author(s):

Na Lu ◽

Shubhashini Oza

Keyword(s):

Thermal Stability ◽

Plasma Treatment ◽

Composite Structures ◽

Treatment Time ◽

Thermo Gravimetric Analysis ◽

Oxygen Plasma Treatment ◽

Gravimetric Analysis ◽

Hemp Fiber ◽

Physical And Chemical ◽

Thermal Stability Of

Hemp fiber is an excellent sustainable and renewable alternative to glass fiber as a reinforcing component in composite system, owing to its unique features of fast growth, high mechanical strength, low density, low cost, biodegradable, and low energy consumption. In this study a systematic investigation of physical and chemical treatment on hemp fiber was conducted, and their effects on thermal stability of hemp fiber were analyzed. Oxygen plasma treatment was used as physical modification approach, 5 wt% sodium hydroxide solution was used for chemical modification. Surface chemical composition and thermal stability were characterized by Fourier transform infrared spectroscopy and thermo gravimetric analysis. The results indicated that 5 wt% of NaOH with 16 hours treatment time increased hemp fiber thermal stability, while the plasma treatment had no impact on thermal stability of hemp fiber.

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Boehmite Nanofillers in Epoxy Oligosiloxane Resins: Influencing the Curing Process by Complex Physical and Chemical Interactions

Materials ◽

10.3390/ma12091513 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1513

Author(s):

Ievgeniia Topolniak ◽

Vasile-Dan Hodoroaba ◽

Dietmar Pfeifer ◽

Ulrike Braun ◽

Heinz Sturm

Keyword(s):

Thermal Stability ◽

Glass Transition ◽

Particle Surface ◽

Nanocomposite Coating ◽

Material Behavior ◽

Hydroxyl Groups ◽

Toluenesulfonic Acid ◽

Physical And Chemical ◽

Thermal Stability Of

In this work, a novel boehmite (BA)-embedded organic/inorganic nanocomposite coating based on cycloaliphatic epoxy oligosiloxane (CEOS) resin was fabricated applying UV-induced cationic polymerization. The main changes of the material behavior caused by the nanofiller were investigated with regard to its photocuring kinetics, thermal stability, and glass transition. The role of the particle surface was of particular interest, thus, unmodified nanoparticles (HP14) and particles modified with p-toluenesulfonic acid (OS1) were incorporated into a CEOS matrix in the concentration range of 1–10 wt.%. Resulting nanocomposites exhibited improved thermal properties, with the glass transition temperature (Tg) being shifted from 30 °C for unfilled CEOS to 54 °C (2 wt.% HP14) and 73 °C (2 wt.% OS1) for filled CEOS. Additionally, TGA analysis showed increased thermal stability of samples filled with nanoparticles. An attractive interaction between boehmite and CEOS matrix influenced the curing. Real-time infrared spectroscopy (RT-IR) experiments demonstrated that the epoxide conversion rate of nanocomposites was slightly increased compared to neat resin. The beneficial role of the BA can be explained by the participation of hydroxyl groups at the particle surface in photopolymerization processes and by the complementary contribution of p-toluenesulfonic acid surface modifier and water molecules introduced into the system with nanoparticles.

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Investigation of physical and chemical properties, performance and behavior in fire conditions of epoxy compositions modified with inhibitory fillers

Journal of Physics Conference Series ◽

10.1088/1742-6596/2131/4/042044 ◽

2021 ◽

Vol 2131 (4) ◽

pp. 042044

Author(s):

D Totskiy ◽

V Borisova ◽

A Davidenko ◽

E Kadochnikova ◽

N Loran

Keyword(s):

Thermal Stability ◽

Experimental Study ◽

Chemical Properties ◽

Thermal Insulating ◽

Operational Characteristics ◽

And Behavior ◽

In Fire ◽

Physical And Chemical ◽

Thermal Stability Of ◽

And Chemical Properties

Abstract The presented article presents the results of investigations of operational characteristics and thermal stability of polymer composites whose matrix is represented by epoxy resins modified with different kinds of inhibiting fillers. An analytical literature review has been performed, methods and methods of obtaining flame retardant composites have been studied. Experimental study of the influence of inhibiting modifiers - fine fillers: iron oxide, silica flour, graphite, talcum, copper oxide has been carried out. According to the results of the experimental study, the modification of the epoxy matrix of the composite by the introduction of inhibiting fillers by ultrasonic treatment contributes to an increase in thermal stability. The modified material is characterized by decrease of intensity of destruction of the material matrix, expressed in decrease of mass loss level, decrease of maximum value of thermal effect, increase of oxidation period, and also steady formation of a thermal insulating carbonaceous layer.

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The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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Microstructure studies of tungsten silicide schottky contacts on Gaas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126445 ◽

1987 ◽

Vol 45 ◽

pp. 328-329

Author(s):

Yih-Cheng Shih ◽

E. L. Wilkie

Keyword(s):

Thermal Stability ◽

Field Effect Transistors ◽

Schottky Contact ◽

Schottky Contacts ◽

Excellent Thermal Stability ◽

Barrier Heights ◽

Gaas Substrates ◽

Film Adhesion ◽

Threshold Voltages ◽

Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

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