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Organic radicals can potentially play important roles in functional materials owing to an unpaired electron, but they are usually highly reactive and difficult to use. Therefore, stabilization of organic radicals is important. Among organic radicals, carbon-centered radicals are promising because of their trivalent nature, which enables structural diversity and elaborate designs, but they are also less stable because of the reactivities towards carbon-carbon bond formation and atmospheric oxygen. Recently, stable carbon-centered radicals across diverse molecular platforms have been increasingly explored. This Minireview highlights these newly explored, stable carbon-centered radicals, with a focus on porphyrinoid-stabilized radicals because of their remarkable spin delocalization abilities.

The present atmosphere of Venus contains almost no water, but recent measurements indicate that in its early history, Venus had an Earth-like ocean. Understanding how the Venusian atmosphere evolved is important not only for Venus itself but also for understanding the evolution of other planetary atmospheres. In this study, we quantify the escape rates of oxygen ions from the present Venus to infer the past of the Venusian atmosphere. We show that an extrapolation of the current escape rates back in time leads to the total escape of 0.02-0.6 m of a global equivalent layer of water. This implies that the loss of ions to space, inferred from the present state, cannot account for the loss of an historical Earth-like ocean. We find that the O+ escape rate increases with solar wind energy flux, where more energy available leads to a higher escape rate. Oppositely, the escape rate decreases slightly with increased extreme ultraviolet radiation (EUV) flux, though the small variation of EUV flux over the measured solar cycle may explain the weak dependency. These results indicate that there is not enough energy transferred from the solar wind to Venus' upper atmosphere that can lead to the escape of the atmosphere over the past 3.9 billion years. This means that the Venusian atmosphere did not have as much water in its atmosphere as previously assumed or the present-day escape rates do not represent the historical escape rates at Venus. Otherwise, some other mechanisms have acted to more effectively remove the water from the Venusian atmosphere. Plain Language Summary Today, Venus only has small amounts of water in its atmosphere. In its early history, Venus presumably contained an Earth-like ocean of several meters. The evolution of the atmosphere may have been caused by escape of atmospheric content to space. In this study, we investigate how much the escape of oxygen ions to space could have affected the atmospheric evolution for Venus from measurements of the present-day escape rates. Using measurements of oxygen ions in the vicinity of Venus, we show that the amount of energy available in the solar wind to be transferred to the upper atmosphere of Venus determines how much of the atmosphere escapes. From the evolution of the energy in the solar wind over the past 3.9 billion years, together with the relation between the solar wind energy and oxygen ion escape, we show that in total, about 0.02-0.6 m of water depth, if spread equally over the entire Venusian surface, was lost. This indicates that either Venus did not have as much water as previously assumed or the current escape rates are not representative of the historical escape rates. Otherwise, some other mechanisms must have acted to more effectively remove the water from Venus.

Greater public, and research, focus on oceanic and atmospheric oxygen budgets is needed. Oceans are “losing their breath”; there has been a 1-2% loss, 77-154 gigatons (GT) of total oceanic oxygen (...

The oxidative cleavage of 1,2-diols is a fundamental organic transformation. The stoichiometric oxidants that are still predominantly used for such oxidative cleavage, such as H5 IO6 , Pb(OAc)4 , and KMnO4 , generate stoichiometric hazardous waste. Herein, we describe a widely applicable and highly selective silver(I)-catalyzed oxidative cleavage of 1,2-diols that consumes atmospheric oxygen as the sole oxidant, thus serving as a potentially greener alternative to the classical transformations.

The Gaia theory of James Lovelock proposes that the Earth is a self-regulating system, or super-organism, maintaining conditions hospitable to contemporary planetary biota. Objections to this theory, concerning its alleged untestability and circularity, are considered and countered. Favourable evidence includes Lovelock's Daisyworld model of a planet regulating its own temperatures and thus maintaining homeostasis, and his discoveries of actual regulatory mechanisms such as the biological generation of dimethyl sulphide, which removes sulfur from the oceans and seeds clouds whose albedo reduces solar radiation (a negative feedback mechanism). After some decades of scepticism, sections of the scientific community have partially endorsed Gaia theory, accepting that the Earth system behaves as if self-regulating. Whether or not this theory is acceptable in full, it has drawn attention to the need for preserving planetary biological cycles and for the planetary dimension to be incorporated in ethical decision-making, and thus for a planetary ethic. Key Concepts James Lovelock hypothesises that the planetary physical and biological system is a self-regulating super-organism. There were precedents before Lovelock for ascribing life either to the planet or to the universe. James W. Kirchner presents Gaia hypotheses as either unoriginal or untestable. Lovelock demonstrates that Gaia theory is both original and testable, albeit indirectly. Lovelock's theory can readily escape the charge of circularity. Predictions of Gaia theory include the existence of biologically generated mechanisms of planetary regulation. Lovelock's discovery of dimethyl sulphide discloses such a mechanism for the regulation of oceanic sulfur. Both atmospheric oxygen and atmospheric nitrogen turn out to be biologically generated and maintained. Philosophers such as Stephen Clark and Mary Midgley have made Gaia a symbol for the planetary thinking currently needed. The Amsterdam Declaration of planetary scientists (Moore et al., 2001) accepted aspects of Gaia theory, without explicitly accepting the theory's planetary goal. Keywords: Daisyworld model; dimethyl sulphide; feedback mechanisms; Gaia; homeostasis; Lovelock, James; planetary ethic; self-regulating system; super-organism; testability

Herein, polyaniline-grafted vanadyl acetylacetonate [VO(acac)2] was prepared and used as an effective catalyst for the oxidation of 5-hydroxymethylfurfural (HMF) under atmospheric oxygen pressure. A high HMF conversion of 99.2 % was obtained after 12 h at 110 °C, and 2,5-diformylfuran (DFF) was obtained in 86.2 % yield. More importantly, the one-pot conversion of fructose into DFF was also realized with two binary catalysts: Amberlyst-15 and polyaniline–VO(acac)2. Amberlyst-15 was used for the acid-catalyzed dehydration of fructose into HMF, followed by the in situ oxidation of HMF catalyzed by polyaniline–VO(acac)2. DFF could be obtained in a yield of 42.1 % from fructose by using the one-pot reaction, whereas two consecutive steps gave a higher DFF yield of 71.1 %. Owing to the facile catalyst preparation and low cost, this method showed a promising potential for the synthesis of DFF from abundant carbohydrates.

A simple and practical method for synthesizing α-ketoamides has been developed involving Cu(OTf)2-promoted oxidative amidation-diketonization of terminal alkynes with primary/secondary amines. This method has a wide substrate scope, and atmospheric oxygen acts as the oxidant.

The physiological performance of a mid-intertidal limpet Cellana toreuma was determined to study the physiological adaptation of intertidal animals to rapid changes and extreme temperatures during emersion. The relationship between the Arrhenius breakpoint temperature (ABT) and in situ operative body temperature was studied to predict the possible impact of climate change on the species. The temperature coefficient (Q10) of emersed animals was higher than that of submersed animals and the ratio of aerial: aquatic heart rate rose with increasing temperature. The ABTs of submersed and emersed animals were 30.2 and 34.2°C, respectively. The heart rate and levels of molecular biomarkers (hsps, ampkα, ampkβ and sirt1 mRNA) were determined in 48 h simulated semi-diurnal tides. There were no obvious changes of heart rate and gene expression during the transition between emersion and submersion at room temperature, although expressions of hsp70 and hsp90 were induced significantly after thermal stress. These results indicate that C. toreuma can effectively utilize atmospheric oxygen, and the higher Q10 and ABT of emersed animals are adaptations to the rapid change and extreme thermal stress during emersion. However, the in situ operative body temperature frequently exceeds the aerial ABT of C. toreuma, indicating the occurrence of large-scale mortality of C. toreuma in summer, and this species should be sensitive to increasing temperature in the scenario of climate change.

A novel oxidative coupling of acetophenones with N,N-dimethylformamide to synthesize aryl-α-ketoamides was developed by using copper oxide and iodine as the additives. For this conversion, DMF works not only as the solvent but also as the surrogate of dimethylamine. Besides, additional oxidants, such as peroxides or dioxygen, are not necessary, and atmospheric oxygen acts as the oxidant.

Cyclic β‐oxo esters are converted with enol acetates in a cerium‐catalyzed, oxidative Umpolung reaction to furnish 1,4‐diketones with up to 95 % yield. Atmospheric oxygen is the oxidant in this process, which can be regarded as ideal from economic and ecological points of view. Further advantages of this new C–C coupling reaction are its operational simplicity and the application of nontoxic and inexpensive CeCl3 ·7H2O as precatalyst.

Recent studies challenge the classical view that the origin of animal life was primarily controlled by atmospheric oxygen levels. For example, some modern sponges, representing early-branching animals, can live under 200 times less oxygen than currently present in the atmosphere - levels commonly thought to have been maintained prior to their origination. Furthermore, it is increasingly argued that the earliest animals, which likely lived in low oxygen environments, played an active role in constructing the well-oxygenated conditions typical of the modern oceans. Therefore, while oxygen is still relevant to understanding early animal evolution, the relationships between the two might be less straightforward than previously thought.

A copper(II)-catalysed approach to oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines via formal C-H, Ar-H coupling is described. In a new variant, copper(II) 2-ethylhexanoate has been identified as an inexpensive and efficient catalyst for this transformation, which utilises atmospheric oxygen as the re-oxidant.

An efficient protocol for the Pd-catalyzed regiospecific ortho-nitration of (E)-azoarenes has been achieved for the first time using tBuONO as a nitrating agent under atmospheric oxygen. A series of both symmetrical and unsymmetrical azoarenes were nitrated efficiently by this procedure providing excellent chemo- and regioselectivity and compatibility with a broad array of functional groups.

Feuer sind seit dem Auftreten der ersten Landpflanzen im Oberen Silur vor etwa 425 Mio. Jahren ein naturlicher Faktor in der Biosphare. Der Nachweis von fossilen Vegetationsbranden erfolgt durch Holzkohle oder charakteristische aromatische Kohlenwasserstoffe, die bei Branden entstehen. Neben dem Vorhandensein von Brennstoffen (=pflanzliche Biomasse) und Zundquellen (vor allem Blitze) wurde das Auftreten von Branden in der Erdgeschichte auch von wechselnden Sauerstoffkonzentrationen in der Atmosphare und von Klimaanderungen beeinflusst. Auch wenn unser Wissen uber Feuer fur manche Abschnitte der Erdgeschichte noch luckenhaft ist, konnen unsere Kenntnisse uns helfen zu verstehen, wie sich zukunftige Klimaanderungen auf die Feuerokologie heutiger Okosysteme auswirken konnten. Fires in the Earth history Fire is a naturally occurring factor in the biosphere ever since the first appearance of land plants in the Late Silurian about 425 million years ago. Charcoal and characteristic polyaromatic hydrocarbons can be used as evidence for such palaeo-wildfires. Besides the presence of fuel (=plant biomass) and sources of ignition (i.e. lightning strikes) the most important factors influencing the occurrence of fires throughout the Earth history are varying atmospheric oxygen concentrations and climatic changes. Although our knowledge about palaeo-wildfires remains incomplete for several periods of the Earths history it is possible to use the existing knowledge to gain a better understanding of the possible impacts of current and future climate change on the fire-ecology of modern ecosystems.

A new dehydrogenative C–H activation of uracil in an open atmosphere was developed to synthesize pyrrolo-pyrimidines, which are potentially bioactive molecules. This new approach establishes the selective catalytic activity of Cu(OTf)2 to accomplish the uracil C-6–H activation.

A convenient and efficient synthesis of symmetrical and asymmetric thiosulfonates from thiols and sodium sulfinates is reported. The protocol involves iron(III)-catalyzed formation of sulfenyl and sulfonyl radicals in situ under aerobic conditions and their subsequent cross-coupling to afford thiosulfonates in 83–96% yield. The utilization of readily available, nontoxic, and inexpensive iron(III) as a catalyst and atmospheric oxygen as an oxidant is within the confines of green and sustainable chemistry.

Formation of δ-lactones is observed when cyclopentanone-2-carboxylates are converted in a cerium-catalyzed reaction with α-aryl vinyl acetates under oxidative conditions. The products of this transformation possess a 1,4-dicarbonyl constitution together with a quaternary carbon center. Atmospheric oxygen is the oxidant in this process, which can be regarded as ideal from economic and ecological points of view. Further advantages of this new C–C coupling and oxidation reaction are its operational simplicity and the application of nontoxic and inexpensive CeCl3·7 H2O as precatalyst. This so far unprecedented reaction is proposed to proceed via 1,2-dioxane derivatives, which decompose under formation of an oxycarbenium cation in a Baeyer–Villiger-type pathway. This mechanistic picture is supported by the observation that electron-rich (donor substituted or heteroaromatic) enol esters give higher yields than electron deficient congeners. Apart from 1,4-diketones and α-hydroxylated β-oxoesters formed as byprod...

A novel oxidative coupling of acetophenones with N,N-dimethylformamide to synthesize aryl-α-ketoamides was developed by using copper oxide and iodine as the additives. For this conversion, DMF works not only as the solvent but also as the surrogate of dimethylamine. Besides, additional oxidants, such as peroxides or dioxygen, are not necessary, and atmospheric oxygen acts as the oxidant.

Regioselective synthesis of 4-hydroxybiphenyl-2-carboxylates via the base-mediated oxygenative [3 + 3] benzannulation reaction of α,β-unsaturated aldehydes and γ-phosphonyl crotonates is reported. A hydroxyl group is installed in the final product on the originally phosphorus-bound carbon via a novel oxygenative and dehydrogenative transformation. The reaction proceeds rapidly in an open flask, uses atmospheric oxygen as an oxidant, and affords good yields of substituted biaryl phenols.

An efficient method for the 2-hydroxylation of 1,3-diketones by using atmospheric oxygen as an oxidant under transition-metal-free condition is described. The protocol has the advantages of using an inexpensive and stable oxidant, producing high yields, and requiring ecofriendly conditions.

An eco-efficient, clean, and photoredox catalyzed synthesis of highly functionalized pyrazole derivatives in good to excellent yields is reported.

Efficient methods for the preparation of 1-hydroxy-1,5-dihydro-2H-pyrrol-2-ones and 1-hydroxy-1,6-dihydropyridine-2,5-diones from N-hydroxy-N-(2-oxoalkyl)amides are reported. It was found that the reaction of N-hydroxy-N-(2-oxoalkyl)amides with 3 equiv of potassium tert-butoxide led to 1-hydroxy-1,5-dihydro-2H-pyrrol-2-ones. A decrease of the base content to 1.5 equiv or less led to an increase of 1-hydroxy-3-phenyl-1,6-dihydropyridine-2,5-dione in the reaction due to oxidation of the starting materials by atmospheric oxygen and their subsequent transformation.

Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian-Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by-product of paleo-fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model-based calculation suggests that the O2 levels near the Wuchiapingian/Changhsingian boundary and the Permian-Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the Permian-Triassic boundary crisis.

So far only very few reports deal with Triassic (especially macro- or mesofossil) charcoal in detail. Here we present the first results of a detailed study of fossil charcoal from Late Triassic sandstones of the Tubingen Sandstein (Exter-Formation, Rhaetian) in the vicinity of Tubingen in SW Germany. The discovery of charcoal at this locality can be regarded as direct evidence of wildfires in the hinterland of the Rhaetian sea and all charcoal fragments studied so far represent gymnosperm woods. At the moment nothing can be stated about the frequency and extent of such fires, although the occurrence of charcoal in different sandstone-bodies points to more than one fire event. The charcoal content of the marginal marine deposit probably represents a larger region and not only the vegetation in the direct vicinity of the shore. A considerable amount of transport is indicated by abrasion of some of the charcoal fragments and the taphonomic sorting, leading to the selected accumulation of woody fragments. Some charcoal fragments are permineralized by goethite and we assume that in this case the goethite is the primary permineralization agent. Our data support the assumption that during the Late Triassic atmospheric oxygen concentrations were high enough to sustain larger wildfires. Copyright © 2010 John Wiley & Sons, Ltd.

As a contribution to the study of the formation of humic acids in soil, a polarographic investigation has been made of the oxidation of some poly-hydroxybenzenes in aqueous solution under different conditions. The formation of hydroxyquinone as an intermediate in the oxidation of hydroquinone was confirmed. Indications were obtained for the identity of some other intermediate reaction products. The important conclusion is drawn that the presence of tyrosinase or certain clay-minerals frequently not only influences the reaction velocity, as is sometimes supposed, but also may alter the course of the oxidation reaction.

An efficient procedure for the oxidative coupling of alkyl, aryl and heteroaryl thiols with atmospheric oxygen is reported. The methodology utilizes BMIM-BF4 as a recyclable solvent and does not require support materials or metal salts. Symmetric disulfides are obtained in excellent yields.

Reduction kinetics of thionine (Th) with D-galactose (RH) was observed on a UV/Visible 1601 Shimadzu spectrophotometer at λmax 599 nm. The results showed that the initially slow reduction kinetics got enhanced and proceeded to completion within a few minutes. A pseudo first order kinetics was observed when influence of different parameters like concentration of dye and reductant, ionic strength and temperature was investigated. A significant shift in wave length from 599 to 517 nm was observed at alkaline pH whereas addition of a small amount of acid caused a shift in equilibrium. This resulted in the generation of oxidized form of thionine which was pragmatic in the presence of atmospheric oxygen. Change in ionic strength at elevated temperature lied to decrease in the rate constant. Thermodynamics activation parameters like Ea reflects a high amount of energy required for reduction of Th with RH whereas entropy of activation (ΔS⊖) and free energy of activation (ΔG⊖) show the highly solvated states of transient complex which was less disorderly arranged than the oxidized form of dye. A mechanism consistent with above findings has been discussed in the relevant section of paper.

The effect on corneal sensitivity of exposing the cornea to reduced partial pressure of atmospheric oxygen for up to 10 h was evaluated. It was found that corneal sensitivity diminished markedly with 2.1% and 3.15% partial oxygen pressure. It is suggested that lower than normal oxygen pressure at the corneal surface is mainly responsible for significant changes in corneal sensitivity.

The effect of soft contact lens (SCL) wear on corneal endothelium was studied with a noncontact specular microscope in 21 unadapted young volunteers. In 4 cases the specular reflection remained intact. In 6 cases the specular reflection was abnormally pronounced in the cell periphery and less pronounced in the central cell area. Nine of 21 eyes presented also nonreflecting areas or blebs. In 2 individuals these changes were extensive. The changes appeared 4 to 10 min after the contact lens (CL) insertion and reached a maximum after 15 to 40 min. The endothelial mosaic returned to normal about 30 min after removal of the CL. The endothelial bleb reaction and the role of atmospheric oxygen flux to the endothelium is discussed.

The potentials at which iron is converted into anhydrous cubic oxide in certain inhibitive solutions have been measured and it has been shown that these potentials are more negative than the potentials acquired by unpolarised specimens immersed in the solutions for 3 days. It is suggested that when iron, carrying its air-formed film, is placed in an inhibitive solution, saturated with air, the corrosion current is concentrated at the weak spots in the oxide film and at the air-formed film is thereby thickened and corrosion prevented. When the pH of the inhibitive solution exceeds 9, anhydrous cubic oxide may also be formed by the interaction of the anodic product, ferrous hydroxide, with atmospheric oxygen. This explanation of inhibition has been extended to account for the corrosive nature of pure water, the effect of the concentration of the inhibitor, the dual rǒle of oxygen and the effect of oxygen on the efficiency of non-oxidising inhibitors.

Tubes of polythene, polypropylene, furfural polymer (‘Tygon’) or polytetrafluoroethylene are normally permeable to atmospheric oxygen when deoxygenated water flows through them. Both polypropylene and Tygon can achieve a state of impermeability after prolonged contact with water, and this is due to the steady-state water transmission through the tube-wall becoming sufficiently vigorous to exclude the oxygen that attempts to penetrate in the opposite direction. It is shown that the achievement of oxygen impermeability by this mechanism can depend on the cross-sectional dimensions of the tube. Hence only the smaller of two polypropylene tubes achieved impermeability to atmospheric oxygen. On account of the special conditions required for oxygen impermeability, it is considered that none of the four types of polymer tubing tested in this work is suitable for routine use in the sampling of water before microdetermination of dissolved oxygen.

The nature of the mixed phosphates present in coatings produced by the action of phosphoric acid on a clean steel surface has been investigated. It has been shown that the coating composition changes with time of exposure to atmospheric oxygen. The role of oxygen in the reaction mechanism is discussed.

A direct intermolecular olefination of sp3 C–H bond between 2-oxindoles and simple alkenes via a Cross-Dehydrogenative Coupling (CDC) strategy has been developed. In the absence of additional base, moderate to excellent yields have been obtained by using a catalytic amount of iodine with atmospheric oxygen as the reoxidant. Based on the observation of a radical capture experiment, the transformation is proposed to proceed via a radical process.

In the presence of atmospheric oxygen, secondary and primary amines can be used in the title process.

An efficient and metal-free method for the one-pot synthesis of various 5-substituted 2-amino-1,3,4-oxadiazoles (II) utilizing visible light and atmospheric oxygen under mild reaction conditions is developed.

The direct carbonylation of C—H bonds of aromatic and aliphatic amides is achieved via nickel/copper synergistic catalysis under atmospheric oxygen with the assistance of a bidendate directing group.

ConspectusRedox-neutral methods for the functionalization of amine α-C–H bonds are inherently efficient because they avoid external oxidants and reductants and often do not generate unwanted byproducts. However, most of the current methods for amine α-C–H bond functionalization are oxidative in nature. While the most efficient variants utilize atmospheric oxygen as the terminal oxidant, many such transformations require the use of expensive or toxic oxidants, often coupled with the need for transition metal catalysts.Redox-neutral amine α-functionalizations that involve intramolecular hydride transfer steps provide viable alternatives to certain oxidative reactions. These processes have been known for some time and are particularly well suited for tertiary amine substrates. A mechanistically distinct strategy for secondary amines has emerged only recently, despite sharing common features with a range of classic organic transformations. Among those are such widely used reactions as the Strecker, Mannich, P...

We present here a facile and practical procedure for the synthesis of tetrasubstituted furans from alkynes catalyzed by palladium acetate together with cupric acetate in acetic acid, using atmospheric oxygen as a terminal oxidant. Various internal aromatic alkynes afforded the target furans in satisfactory yield.

An extremely technically simple cross-methylation of aryl and vinyl halides and pseudohalides using an air-stable adduct of trimethylaluminium with a Pd(0) catalyst supported by commercially available biarylphosphines gives excellent yields of methylated products (mainly >95%). Reactions can be run with either 0.5 mol % catalyst or without requiring the exclusion of atmospheric oxygen or the drying of solvents in some cases. A wide variety of functional groups is tolerated including CN, OH, CO 2 R, CHO and NO 2 .

A mild, simple, metal-free, direct, and rapid protocol for difunctionalization of alkenes using thiophenols and atmospheric oxygen is presented.

Die Wirksamkeit handelsublicher Saureinhibitoren wird durch eine Auslagerung von Grobblechen aus Behalterstahl uber 1000 Stunden in technisch gebrauchlichen Losungen der Feuerverzinkung untersucht. Ortliche Korrosion ist als Muldenkorrosion in Gegenwart von Saureinhibitoren vor allem in Salzsaurebeizen (20 g/l HCl) bei Raumtemperatur und in salzsaurehaltigen Reinigern (10–30 g/l HCl) bei 40°C aufgetreten, wenn Zusatzbedingungen erfullt sind. Ortliche Korrosion wird vorwiegend durch eine Unterschreitung der Inhibitorkonzentration (0,2 g/l) in Verbindung mit einer minimalen Salzsaurekonzentration (10–30 g/l) ausgelost. Aber auch Oxidationsmittel wie Eisen(III)-Ionen (5–10 g/l), Luftsauerstoff und freies Chlor (100–1000 mg/l) fuhren zu ortlicher Korrosion. In Spulbadern (2–10 g/l HCl) und Flussmittellosungen aus Zinkchlorid und Ammoniumchlorid (pH-Wert: 2,0–5,5) ist keine ortliche Korrosion entstanden, sondern Flachenkorrosion. Im untersuchten Langzeitbereich sind Saureinhibitoren gegen Flachenkorrosion sehr gut wirksam (Hemmwerte bis 99%). Inhibitor efficiency in long-time protection of steel tanks for the chemical surface preparation against local corrosion by process solutions containing hydrochloric acid The efficiency of prevailing acid inhibitors is examined by age hardening heavy tank-steel plates in technically usual hot-galvanizing solutions for 1000 hours. With acid inhibitors local corrosion emerged as shallow pit formation first and foremost in hydrochlorid acid pickles (20 g/l HCl) at ambient temperature as well as in cleaners containing hydrochloric acid (10–30 g/l HCl) at 40°C when other conditions also applied. Above all, local corrosion was produced if the inhibitor concentration became too low (0.2 g/l) in connection with a minimum hydrochloric acid concentration (10–30 g/l). However, oxidizing agents like iron(III)-ions (5–10 g/l), atmospheric oxygen and free chlorine (100–1000 mg/l) lead to local corrosion, too. Local corrosion did not emerge in rinse baths (2–10 g/l HCl) and fluxing material solutions of zinc chloride and ammonium chloride (pH value: 2.0–5.5). Here uniform corrosion developed. Acid inhibitors turned out to be very effective against uniform corrosion in the examined long-time period (inhibiting values up to 99%).

A method for high-precision and high-accuracy mass spectometric measurements of the ratios among the three oxygen isotopes, and of the O2/Ar ratio, is presented. It involves separation of the O2-Ar mixture from air and includes a fully automated system that ensures highly reliable sample processing. Repeated measurements of atmospheric oxygen yield the repeatability (±SE × t, standard error of the mean (n = 12) multiplied by Student's t-factor for a 95% confidence limit) of 0.004, 0.003 and 0.2‰ for δ18O, δ17O and δO2/Ar, respectively. Copyright © 2003 John Wiley & Sons, Ltd.

Mitochondria have been put forward as the saviours of anaerobes when their environment became oxygenated. However, despite oxygenic photosynthesis evolving around 2.7 billion years ago (Ga), followed by the "Great Oxidation" of the atmosphere ~ 2.4 Ga, the deep oceans remained largely anoxic and either iron-enriched or sulphidic until 580 million years ago, when the eukaryotic radiation was well underway. Atmospheric oxygen probably remained at an intermediate concentration (1-10% of the present level) from ~ 2.4 until ~ 0.8 Ga when a "lesser oxidation" began. This drastically changes the textbook view of the ecological conditions under which the mitochondrial endosymbiont established itself. It could explain the widespread distribution of anaerobic biochemistry in every eukaryotic supergroup: anaerobic biochemistry is hard-wired into the eukaryotes.

This study represents the first systematic investigation of long-term anhydrobiotic survival in tardigrades, rotifers and nematodes inhabiting mosses and lichens. Sixty-three different samples from public and private collections, kept dry for 9-138 years, were examined. Rotifers of the genus Mniohia and the eutardigrade Ramazzottius oberhaeuseri (hatched from eggs) were found alive from one of the samples (9 years old). These observations represent the longest record for rotifers in the anhydrobiotic state. For tardigrades, our results confirm previous reports on the upper limit of anhydrobiotic survival under atmospheric oxygen conditions. This study suggests the possibility that tardigrade eggs are able to withstand longer periods in anhydrobiosis than animals. Some problems related to the evaluation of long-term anhydrobiotic survival, such as contamination and chemical treatments of samples, are reported. The possible role of the microenvironment in which the anhydrobiotic animals are kept is discussed.

Silica-supported casein–Co complex (Si-CA–Co) was prepared from silica, casein and cobalt chloride, and found to be useful as a chiral catalyst for the asymmetric epoxidation of cinnamyl alcohol to (2R,3R)-(+)-3-phenylglycidol at 70 °C and under 1 atmospheric oxygen pressure. When a proper content of cobalt in the Si-CA–Co complex and suitable reaction conditions were selected, the product and optical yield could be amounted to 70.6 and 92.0%, respectively, and the Si-CA–Co complex could be reused several times without any remarkable change in the optical catalytic activity. Copyright © 2002 John Wiley & Sons, Ltd.