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Copyright of Natures Sciences Sociétés is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The complexes of poly A and poly U are interesting models for studying the structure of nucleic acids. In the first part of this paper, the thermal stability of these complexes has been studied as a function of both pH and ionic strength in alkaline solution. The thermal stability is measured by the half transition temperatures, or Tm's. There are four different kinds of transitions: Tm2-1 refers to the dissociation of the two-stranded complex, poly (A + U); Tm2-1 to the dissociation of the three-stranded complex, poly (A + 2U) [4]. Tm8-2 is the temperature of half dissociation of poly (A + 2U) into poly (A + U) [1], and Tm2-3 is the temperature of rearrangement of 2 poly (A + U) into poly (A + 2U) [3] (Fig. 1). It is found that Tm2-1, and Tm8-1 decrease as pH increases above neutrality (Fig. 2 and 3), but that Tm2-8 does not vary (Fig. 3). This effect is readily explained if it is assumed that the ionisation of uracil brings a change in the state of the free poly U, but that the complexes themselves are not modified. In the second part of the paper a simple thermodynamic formulation is given which represents satisfactorily the relationship between the four equilibria, as observed at neutral pH (Fig. 1). A more complex treatment is then presented. It includes quantitation of electrostatic interactions, according to the theory of Kotin [18] and of the free enthalpy term corresponding to the organisation (stacking) of poly A. This leads to an excellent representation of the experimental data (Fig. 5). In alkaline solution, one can calculate the free enthalpy change associated with the ionisation of poly U at the Tm. According to our observations, it is likely that this is the only factor responsible for the decrease of Tm. Therefore, we can write that the sum of the free enthalpy of complex formation in the same conditions, but at pH 7, and of the free enthalpy of ionisation is zero. This leads to a determination of ΔG both as a function of temperature and ionic strength: the variation of ΔG with these factors is shown to be in good agreement with our detailed model. However, the absolute values are different, probably because of uncertainties concerning the data for poly A stacking enthalpy and entropy. Apart from providing evaluation of the thermodynamic parameters for double and triple helix formation, our results lead us to emphasize the importance of the thermodynamic state of the unassociated polynucleotides. This may be particularly relevant when one considers the partially complementary secondary structures of RNA's. [ABSTRACT FROM AUTHOR]

Currently, researchers have indicated that inorganic minerals in reservoirs, such as clay minerals, carbonates and quartz, can catalyze the evolution of organic matter into oil and gas. Therefore it is reasonable to believe that the minerals in reservoirs may act as a catalyst support with the metal-containing catalyst added from outside during the thermal recovery of heavy oil. This paper studied the aquathermolysis of heavy oil catalyzed by minerals and transition metal. The reaction conditions of two heavy oil samples were investigated. The results show that the optimal reaction conditions of heavy oil from Xinjiang Baikouquan Oilfield (XBO) are the reaction temperature of 250 °C and the reaction time of 6 h; for the crude oil from Xinjiang Tahe Oilfield (XTO), the optimal reaction conditions are determined to be the reaction temperature of 250 °C and the reaction time of 12 h, the water–oil ratio of the two oils is 0.3. Under optimal conditions, viscosity and pour point of heavy oil are significantly reduced. Differential scanning calorimetry (DSC), GC-MS analysis, thermogravimetric analysis (TGA), and elemental analysis were used to study the properties of the two heavy oil samples before and after reaction to explore the mechanism of the catalyzed aquathermolysis of heavy oil. This work will benefit the related heavy oil recovery work in this field.

The present paper introduces soil as a complex system, so a multidisciplinary approach is needed to study not only the composition, abundance, and transport of microplastics (MPs) in terrestrial ecosystems but also soil properties and processes involved in their degradation and/or interaction with soil polyphasic matrix. Despite many researchers focusing their studies on the impact of MPs on the terrestrial ecosystem over the past years, little has been done about the use of biochemical indicators to study their effect on soil functionality.

It is a matter of strategic independence for many countries to urgently find processes that take into account environmental and economic issues when recycling critical metals. Liquid–liquid (L/L) extraction is a promising method for recovering rare-earth elements from electrical and electronic waste. However, an optimized process on an industrial scale has not yet been established. One of the main reasons is the lack of fundamental knowledge. Therefore, designing a cost-effective and adaptive formulation is still beyond the scope of possibilities. This requires deciphering the molecular forces that control ion transfer beyond the classical supramolecular complexation and developing predictive models compatible with the design and control needs of recycling processes. In all liquid/liquid processes, the high loading of the organic solvent with metal salts/acids or extractant can sometimes lead to a third phase formation. Phase modifiers are often added to the solvent phase in order to prevent the formation of this third phase. However, the effect of these additives on the extraction efficiency as well as their mechanisms of action are still poorly understood. The phase modifiers used in industrial processes are mainly fatty alcohols, called “lipotropes”. In this paper, we study a new class of molecules opening new possibilities beyond the commonly used phase modifiers (i.e., n-octanol). These are the “hydrotropic” molecules. We first show the role of a model hydrotrope (PnP) in preventing the third phase formation for different extraction systems. We also show that the role of modifiers can be understood according to three molecular mechanisms: as co-solvent, as co-surfactant and by preferential solvation. The dominant molecular effect can be identified and quantified by combining surface tension and neutron scattering experiments. In the case of phase modifiers that are hydrotropes, the co-solvent or co-surfactant effect is dominant. In the case of “lipotropes”, the preferential solvation mechanism is emphasized. Finally, the consequences of these mechanisms on the extraction efficiency and selectivity are discussed.

NiO-based catalysts are among the most active and selective catalytic systems for low-temperature oxidative dehydrogenation (ODH) of ethane into ethylene and, therefore, they have been extensively studied in the last twenty-five years. This paper reviews the most relevant works focusing on NiO-based catalysts for ethane ODH, including promoted and unpromoted, bulk and supported NiO. The effects of the nature of the promoter and of the support together with the influence of the method of preparation used on their activity in ethane ODH are discussed in detail as they were shown to be key factors controlling the catalytic performance, including the catalyst stability. The reaction mechanism involved in ethane ODH reaction over NiO-based catalysts is also presented and discussed.

The SCR-DeNOx commercial catalysts are reported as possible candidates to remove aromatic VOCs and NO$_{{x}}$ simultaneously. In this paper, we present the kinetic studies of the oxidation of benzene and its mono-halogenated derivatives over V$_{2}$O$_{5}$–WO$_{3}$/TiO$_{2}$ catalyst as typical high-dust SCR-DeNOx system. The kinetic investigation follows the influence of temperature on the conversion of aromatic VOCs to establish the apparent energy activation and dependence on between temperature and the effective constant rate of the catalytic oxidation reaction. The data shows that the catalytic oxidation process takes place after a combined kinetic mechanism, mass transport through pores—chemical transformation.

The California State Parks curators granted access to artifacts owned by Jack London that are in storage in their Sonoma Barracks in Sonoma, CA. A medicine case, drug vials, and various paper documents that covered the period of his life from 1906 to 1915 were examined for drug residues left on their surface. All the objects were tested with the non-invasive surface analysis EVA (ethylene-vinyl acetate) technology, which consist of a foil studded with ground mixed-bed cation/anion exchangers as well as with C$_{8}$ and C$_{18}$ resins. The harvested material collected by the foils was analysed via GC-MS and the following 12 drugs were identified: N-(4-ethoxyphenyl) acetamide, phenyl salicylic acid, morphine, 6-monoacetylmorphine, 3-acetylmorphine, diacetylmorphine, dipenteneglycol, quinine dihydrochloride, quinine base, atropine, scopolamine and hyoscyamine. Despite the claims by his biographers that he used opium, morphine, and heroin on a regular basis this assertion could not be confirmed by the chemical analyses of the objects here tested. Only two opioids were discovered, morphine and diacetylmorphine (heroin) both of which could have been derived from the use of common, legal (over-the-counter) flu and cough medications.

Most papers on kidney stones arising from infection concentrate on the mineral struvite. In this contribution, we would like to call attention to other mineral phases such as highly carbonated calcium phosphate apatite, ammonium urate, and whitlockite, by presenting clinical and chemical data. We start with epidemiological data which emphasize the increase in the prevalence of kidney stones related to infection. Then we present a statistical analysis of more than 85,000 stones which have been analysed at the Laboratoire des Lithiases of Assistance Publique-Hôpitaux de Paris which gives insights regarding the link between urinary tract infection and struvite, carbonated calcium phosphate apatite (carbapatite), and also surprisingly whitlockite. Some information regarding the pathogenesis of kidney stones linked to infection, the nature of the bacteria which have been identified, and the approach to precisely analyse infrared spectra to identify struvite, carbapatite, and whitlockite, conclude this first part. To complete this clinical description, we describe the crystallographic structure and the chemistry of three relevant compounds namely carbonated calcium phosphate, struvite, and whitlockite. To conclude this second part, the dependence of crystallite morphology of struvite on pH and on the presence, or absence, of bacteria, is described. Based on clinical and chemical data, it is becoming clear that struvite is not the only mineral intimately related to renal infectious processes, but that whitlockite and carbapatite with a high carbonation rate are strongly associated with urinary tract infection as well.

Hydrogen peroxide and peroxymonocarbonate anion-based bleach reactions are important for many applications such as paper bleach, waste water treatment and laundry. Nonheme iron(III) complexes, $[\mathrm{Fe}^{\mathrm{III}}(\mathrm{L}^{1-4})\mathrm{Cl}_{2}]$ with the 1,3-bis($2^{\prime}$-Ar-imino)isoindolines ligands ($\mathrm{HL}^{n}$, $n=$1–4, Ar $=$ pyridyl, thiazolyl, benzimidazolyl and N-methylbenzimidazolyl, respectively) have been shown to catalyze the oxidative degradation of morin as a soluble model of a bleachable stain by $\mathrm{H}_{2}\mathrm{O}_{2}$ in buffered aqueous solution. In these experiments the bleaching activity of the catalysts was significantly influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the $\mathrm{Fe}^{\mathrm{III}}/\mathrm{Fe}^{\mathrm{II}}$ redox potentials (in the range of 197–415 mV) controlled by the modification of the electron donor properties of the ligand introducing various aryl groups on the bis-iminoisoindoline moiety. A similar trend but with low yields was observed for the disproportionation of $\mathrm{H}_{2}\mathrm{O}_{2}$ (catalase-like reaction) which is a major side reaction of catalytic bleach with transition metal complexes. The effect of bicarbonate ions might be explained by the reduction of Fe(III) ions and/or the formation of peroxymonocarbonate monoanion, which is a much stronger oxidant and could increase the formation of the catalytically active high-valent oxoiron species.

In this paper, catalytic hydro-deoxygenation (HDO) of bio-oil’s model molecules (acetic acid, 4-ethylguaiacol, and furfural) using Ni$_{2}$P/HZSM-5 catalyst was carried out to better identify the products and make the modeling work of HDO process more reliable. Results showed that low temperatures favored the formation of acetaldehyde and acetone during acetic acid HDO, but disfavored the formation of aromatic hydrocarbons. Acetone was produced via the self-ketonization reaction of acetic acid. In most cases of 4-ethylguaiacol HDO, phenol, cresol, and 2, 4-dimethylphenol were the primary products. For furfural HDO, the major furan and CO products proved that the direct decarbonylation of furfural was the main reaction. Accordingly, the main pathways of acetic acid, 4-ethylguaiacol, and furfural HDO were proposed, which could provide significant guidance for the upgrading of crude bio-oil.

The filtration properties in solid–liquid separation mainly depend upon the filter cake properties, for instance, cake resistance. However, particle size distribution, particle shape, and their arrangements significantly impact cake filtration. This paper aims to review the work done so far and collate both fundamental and applied work with regard to the quantification of cake properties. The cake resistance and cake porosity in terms of shape, as well as varying particle size distribution width, are discussed here. This work summarizes the current state of the technology and recommends advancements and improvements for future research.

Praziquantel and Syloid 244 FP (amorphous silicon dioxide) were ground in a vibrational mill in standard conditions ($15^{\prime}$ or $30^{\prime}$ at 25 Hz). Amorphous solid dispersions were obtained in a very short grinding time (15 min), as testified by DSC, PXRD and ESEM analyses. Samples ground at $15^{\prime}$ and $30^{\prime}$ showed the presence of the same degradation product, as was evident from UPLC, MS and NMR analyses. This short paper brings to light the tremendous lattice de-structuration ability of Syloid 244 FP upon grinding toward Praziquantel as well as its detrimental influence on promoting chemical degradation through ring opening and oxidation.

The rejection of anti-inflammatory drugs by membranes has shown paramount importance in separation membrane processes such as nanofiltration and reverse osmosis (NF/RO) membranes for pharmaceutical industries. Therefore, the main objective of this paper is to use support vector machine (SVM) and artificial neural network (ANN) to model the rejections of anti-inflammatory drugs by NF/RO membranes using 300 experimental data points gathered from the literature. Both approaches (ANN and SVM) gave close results with a slight superiority of the neural networks model demonstrated by its correlation coefficient (R) and root mean square error (RMSE) values of 0.9930 and 1.8094% respectively, in contrast to 0.9900 and 2.2355% for SVM. Sensitivity analysis by the weight method demonstrates that the most relevant variables that influence the rejection of anti-inflammatory drugs are: effective diameter of an organic compound in water “$d_{{c}}$”, molecular length, contact angle, and zeta potential. These input relevant variables have a significant contribution (relative importance superior to 10%).

This paper deals with the electrochemical properties of three iso-structural compounds of general formula [SiW$_{10}$ O$_{36}$(M$_{2}$O$_{2}$E$_{2}$)]$^{6-}$ (M $=$ Mo or W; E $=$ S or O). A first part is focused on their electrochemical behaviors in aqueous medium. A second part concerns the electrocatalytic properties of these compounds in aqueous medium and the preparation of modified glassy carbon electrodes through a layer-by-layer methodology. This method allowed preparing a multilayer system, which was applied to the electroanalysis of iodate anions in aqueous medium with a limit detection of $6.2~\mu \mbox {M}$.

This paper aims to evaluate the simultaneous adsorption of basic red 2 (BR2) and basic violet 3 (BV3) in a binary system in a batch mode using date stones as low cost adsorbents. For both dyes, experimental kinetic data were well fitted by the Brouers–Sotolongo model $(R^{2}= 0.99)$ and intraparticle diffusion was the controlling step in mass transfer mechanisms. The intraparticle diffusion extent was found to be lower for BR2 ($1.13 \times 10^{-11}~\mathrm{cm}^{2}/\mathrm{s}$) than for BV3 ($1.11 \times 10^{-11}~\mathrm{cm}^{2}/\mathrm{s}$) when compared to individual solutions ($1.24 \times 10^{-10}~\mathrm{cm}^{2}/\mathrm{s}$ and $1.76 \times 10^{-11}~\mathrm{cm}^{2}/\mathrm{s}$ for BR2 and BV3, respectively). The equilibrium study revealed lower adsorption capacities (41.95 and 88.91 mg/g for BR2 and BV3, respectively) compared to the individual sorption results (92.00 and 136.00 mg/g for BR2 and BV3, respectively) for both dyes. To assess the extent of competition and the preference of dyes for functional sites, competition and separation factors were calculated suggesting an antagonistic effect as well as a greater affinity for BV3 than for BR2 to the adsorption sites. The equilibrium adsorption results were best fitted by modified Langmuir and $P$-factor Langmuir isotherms for BR2 and BV3, respectively. Besides, based on enthalpy values (16.30 and 30.26 kJ/mol for BR2 and BV3, respectively), the simultaneous adsorption of both dyes was endothermic while the entropy revealed a higher affinity of the investigated adsorbent to BV3. The sorption process in separate systems (BR2 and BV3) was thermodynamically feasible for both dyes with negative free enthalpy values. The comparison to single systems showed an increase of affinity for BV3 contrarily to BR2 and, a decrease of spontaneity with higher extent for BR2.

Copyright of IBS, Immuno-analyse & Biologie Specialisee is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revue Francophone des Laboratoires is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revue Francophone des Laboratoires is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The effect of oxygen in modulating metabolism has been largely investigated in vitro and in animal studies, but very little in humans. This paper focuses on recent literature regarding pathological and physiological situations characterized by chronic exposure to hypoxia, particularly in patients with chronic respiratory insufficiency and in healthy subjects staying at high altitude. The latest allow for very interesting comparison because they do not experience comorbidities observed in patients with chronic respiratory insufficiency and therefore provide a unique model to assess the specific effect of hypoxia on human body and metabolism. [Copyright &y& Elsevier]

This paper focuses on the synthesis of a new silver nanocomposite adsorbent derived from rice husk as raw material. The synthesis is based on triethoxysilane chemistry and the reduction of silver without the aid of reductant chemicals. The derived AgNPs@SiO2 nanocomposites are fully characterized and then used for the removal of mercury (II) from aqueous solutions. The results demonstrated that the affinity of the composite for mercury is high and the removal mechanism is adsorption accompanied by a redox reaction between mercury and silver followed by the formation of calomel and amalgams between silver and mercury. The silver–mercury reaction is complex, and its stoichiometry seems to scale with the silver content. Besides the importance of the surface reactions, the successful implementation of biosourced silica for mercury removal from water is useful for the development of strategies for the valorization of agricultural waste and boosts the concept of circular economy and bioeconomy.

This is a retraction note for the paper originally published as https://doi.org/10.1016/j.crci.2019.09.006.

This is a retraction note for the paper originally published as https://doi.org/10.1016/j.crci.2019.06.002.

Copyright of Revue Archéologique de Picardie is the property of Revue Archeologique de Picardie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)