Aqueous Component Research Articles

Synthesis and Bioactivity of Silver Nanoparticles Against Bacteria (<i>E. coli</i> and <i>Enterococcus sp. </i>) Isolated from Kalamu River, Kinshasa City, Democratic Republic of the Congo

The emergence of new infectious agents is a potential risk associated with genetic manipulation and field cultivation of genetically modified organisms and constitutes a new challenge in molecular epidemiology. The main objective of the current study was to synthesize silver nanoparticles and evaluate the antibacterial activity of these nanoparticles. E. coli and Enterococcus sp. were isolated from wastewater samples collected from Kalamu River. The preliminary characterization of silver nanoparticles was carried out using UV-visible spectrophotometer. Noble metals, such as silver nanoparticles, exhibit unique and adjustable optical properties due to their external plasmon resonance. The reduction of silver ions was monitored by measuring the UV-visible spectrum of the solutions after dilution of a small aliquot (0.2 mL) of the aqueous component. The antibiotic susceptibility test results confirmed the inactivity of these antibiotics tested against the wild strain of Enterococcus sp. The synthesized silver nanoparticles displayed a good antibacterial activity against Enterococcus sp. The synthesis of silver nanoparticles is designed precisely to alleviate this situation; and these results provide a strong evidence that silver nanoparticles can be used to fight antibiotic-resistant bacteria.

Novel liposome-based and in situ gelling artificial tear formulation for dry eye disease treatment.

Artificial tears are widely used in the treatment of dry eye disease, although current formulations do not closely resemble natural tears. The purpose of this study was the design and characterization of a novel in situ gelling artificial tear formulation, containing both lipid and aqueous components, in order to resemble natural tears and replenish the tear film. Liposomes, containing phosphatidylcholine, cholesterol, vitamins A and E, were prepared by the thin-film hydration method. The aqueous phase of the formulation was comprised of gellan gum, hydroxypropyl methylcellulose, levocarnitine, electrolytes (sodium chloride and potassium chloride), trehalose, and borates. The artificial tear was characterized in terms of liposome size, pH, surface tension, and viscosity. In vitro tolerance studies were performed in a human epithelial carcinoma cell line (HeLa) and a murine macrophage cell line (J774). In vivo tolerance was assessed in rabbits. Liposomes presented a unimodal distribution with a mean size of 200.1 ± 4.4 nm. The resulting surface tension was 53.4 ± 1.1 mN/m (at 33 °C) and the pH was 7.6 ± 0.1. The viscosity of the formulation presented a mean value of 4.0 ± 0.1 mPa s within the shear rate interval of 200-1000 s-1 at 33 °C. Cell viability remained higher than 90% in both cell lines. No discomfort or clinical signs were observed in rabbits. The liposome-based and in situ gelling artificial tear formulation presented good tolerance and suitable properties for topical ophthalmic administration. It may be beneficial in the treatment of dry eye disease.

Diagenesis of dinosaur eggshell from the Gobi Desert, Mongolia

In order to test for paleoenvironmental and paleoecological parameters important in dinosaur evolution, thirty-four fragments of dinosaur eggshell, paleosol carbonates from six localities, and calcite crystals from inside a dinosaur femur were collected from the Campanian to Maastrichtian Baruungoyot and Nemegt formations, Gobi Desert, Mongolia. The samples were examined for diagenesis using light microscopy, SEM, and cathodoluminescence, and each was analyzed for δ13C and δ18O values. Eggshell isotope values plot along two trends of enrichment, with paleosol carbonate nodule values plotting along locality specific trends. Convergence of the trends suggests similar initial conditions among localities. Permian-age detrital zircons in the fossiliferous sediment suggest that enriched eggshell and paleosol carbonate nodule δ13C values may have been caused by phreatic zone diagenetic alteration by waters with an aqueous bicarbonate component derived from interaction and dissolution of Permian calcareous marine host rocks. Our hypothetical model for eggshell diagenesis assumes a stable carbon- and oxygen-isotope domain space delimited by three end members: (1) apparently unaltered eggshell with primary microstructure, (2) non-luminescent eggshell with no preserved microstructure, and (3) luminescent eggshell with no preserved microstructure. The two end members showing no preservation of microstructure indicate different phases of diagenetic alteration in the presence of vadose and phreatic waters. None of the samples analyzed can be shown to be sufficiently unaltered for analysis using standard techniques. Biologically, eggshell is porous to facilitate the movement of gases while an embryo is developing within the egg. Geologically, that same property allows the flow of diagenetic ground waters, which modifies the primary isotopic signature of eggshell.

Retention Models on Core-Shell Columns.

A thin, active shell layer on core-shell columns provides high efficiency in HPLC at moderately high pressures. We revisited three models of mobile phase effects on retention for core-shell columns in mixed aqueous-organic mobile phases: linear solvent strength and Snyder-Soczewiński two-parameter models and a three-parameter model. For some compounds, two-parameter models show minor deviations from linearity due to neglect of possible minor retention in pure weak solvent, which is compensated for in the three-parameter model, which does not explicitly assume either the adsorption or the partition retention mechanism in normal- or reversed-phase systems. The model retention equation can be formulated as a function of solute retention factors of nonionic compounds in pure organic solvent and in pure water (or aqueous buffer) and of the volume fraction of an either aqueous or organic solvent component in a two-component mobile phase. With core-shell columns, the impervious solid core does not participate in the retention process. Hence, the thermodynamic retention factors, defined as the ratio of the mass of the analyte mass contained in the stationary phase to its mass in the mobile phase in the column, should not include the particle core volume. The values of the thermodynamic factors are lower than the retention factors determined using a convention including the inert core in the stationary phase. However, both conventions produce correct results if consistently used to predict the effects of changing mobile phase composition on retention. We compared three types of core-shell columns with C18-, phenyl-hexyl-, and biphenyl-bonded phases. The core-shell columns with phenyl-hexyl- and biphenyl-bonded ligands provided lower errors in two-parameter model predictions for alkylbenzenes, phenolic acids, and flavonoid compounds in comparison with C18-bonded ligands.

Revisiting the Analytical Solution Approach to Mixing‐Limited Equilibrium Multicomponent Reactive Transport Using Mixing Ratios: Identification of Basis, Fixing an Error, and Dealing With Multiple Minerals

AbstractMulticomponent reactive transport involves the solution of a system of nonlinear coupled partial differential equations. A number of methods have been developed to simplify the problem. In the case where all reactions are in instantaneous equilibrium and the mineral assemblage is constant in both space and time, de Simoni et al. (2007) provide an analytical solution that separates transport of aqueous components and minerals using scalar dissipation of “mixing ratios” between a number of boundary/initial solutions. In this approach, aqueous speciation is solved in conventional terms of primary and secondary species, and the mineral dissolution/precipitation rate is given in terms of the scalar dissipation and a chemical transformation term, both involving the secondary species associated with the mineral reaction. However, the identification of the secondary species is nonunique, and so it is not clear how to use the approach in general, a problem that is keenly manifest in the case of multiple minerals which may share aqueous ions. We address this problem by developing an approach to identify the secondary species required in the presence of one or multiple minerals. We also remedy a significant error in the de Simoni et al. (2007) approach. The result is a fixed and extended de Simoni et al. (2007) approach that allows construction of analytical solutions to multicomponent equilibrium reactive transport problems in which the mineral assemblage does not change in space or time and where the transport is described by closed‐form solutions of the mixing ratios.

Adsorption of Aqueous Crude Oil Components on the Basal Surfaces of Clay Minerals: Molecular Simulations Including Salinity and Temperature Effects

Molecular simulations of the adsorption of representative organic molecules onto the basal surfaces of various clay minerals were used to assess the mechanisms of enhanced oil recovery associated with salinity changes and water flooding. Simulations at the density functional theory (DFT) and classical levels provide insights into the molecular structure, binding energy, and interfacial behavior of saturate, aromatic, and resin molecules near clay mineral surfaces. Periodic DFT calculations reveal binding geometries and ion pairing mechanisms at mineral surfaces while also providing a basis for validating the classical force field approach. Through classical molecular dynamics simulations, the influence of aqueous cations at the interface and the role of water solvation are examined to better evaluate the dynamical nature of cation–organic complexes and their coadsorption onto the clay surfaces. The extent of adsorption is controlled by the hydrophilic nature and layer charge of the clay mineral. All organ...

Lacrimal gland development: From signaling interactions to regenerative medicine.

The lacrimal gland plays a pivotal role in keeping the ocular surface lubricated, and protecting it from environmental exposure and insult. Dysfunction of the lacrimal gland results in deficiency of the aqueous component of the tear film, which can cause dryness of the ocular surface, also known as the aqueous-deficient dry eye disease. Left untreated, this disease can lead to significant morbidity, including frequent eye infections, corneal ulcerations, and vision loss. Current therapies do not treat the underlying deficiency of the lacrimal gland, but merely provide symptomatic relief. To develop more sustainable and physiological therapies, such as in vivo lacrimal gland regeneration or bioengineered lacrimal gland implants, a thorough understanding of lacrimal gland development at the molecular level is of paramount importance. Based on the structural and functional similarities between rodent and human eye development, extensive studies have been undertaken to investigate the signaling and transcriptional mechanisms of lacrimal gland development using mouse as a model system. In this review, we describe the current understanding of the extrinsic signaling interactions and the intrinsic transcriptional network governing lacrimal gland morphogenesis, as well as recent advances in the field of regenerative medicine aimed at treating dry eye disease. Developmental Dynamics 246:970-980, 2017. © 2017 Wiley Periodicals, Inc.

Salvianolic acid B inhibits intermittent high glucose-induced INS-1 cell apoptosis through regulation of Bcl-2 proteins and mitochondrial membrane potential

Blood glucose fluctuations, also referred to as intermittent high glucose, have been validated to be more harmful than sustained high glucose in exacerbating pancreatic dysfunction by inducing β cell apoptosis. Salvianolic acid B (Sal B), an aqueous component of Salvia miltiorrhiza, has been proved beneficial to pancreatic islet function in diabetes, but the underlying mechanisms remain to be elucidated. The present study investigated the protective effect of Sal B on INS-1 cells exposed to intermittent high glucose and the possible mechanisms implicated. The results indicated that Sal B was able to restore cell viability and suppress INS-1 cell apoptosis induced by intermittent high glucose. Preincubation with Sal B led to a significant decrease of caspase-9 and caspase-3 activity and poly ADP-ribose polymerase (PARP) cleavage. Exposure to intermittent high glucose induced significant up-regulation of proapoptotic proteins, down-regulation of antiapoptotic protein and depolarization of mitochondrial membrane potential (MMP) in INS-1 cells, while these changes were reversed effectively in Sal B treated groups. In addition, Sal B markedly attenuated intermittent high glucose-induced oxidative stress as manifested by notably decreased levels of intracellular reactive oxygen species and malondialdehyde (MDA). Taken together, these results indicate that Sal B is able to suppress intermittent high glucose-induced INS-1 cell apoptosis, which might be ascribed to regulation of Bcl-2 family protein expression and preservation of mitochondrial membrane potential.

Serotonin hormonally regulates lacrimal gland secretory function via the serotonin type 3a receptor

Tears are extracellular fluid secreted from the lacrimal gland (LG). Tears consist of a dynamic tri-layered film composed of secretions from the LG, Meibomian gland, and conjunctival goblet cells. The LG secretes the aqueous component of the tear, the Meibomian gland secretes the lipid component, and conjunctival goblet cells secrete mucin. The regulation of LG activity via the autonomic nervous system has been recognized as fundamental to maintaining aqueous tear flow. Here, we describe the role of a hormone, peripheral serotonin, in tear secretion. We found that blood serotonin concentration, changed by feeding a diet deprived of the serotonin precursor tryptophan, correlated with tear secretion, and that a sustained decrease in serotonin resulted in LG atrophy and autophagy. The combination of a decrease in serotonin with the interruption of autonomic neural stimuli to the LG preceded these alterations. Furthermore, we found that the serotonin type 3a receptor expressed in LG acinar cells is involved in tear secretion via intracellular calcium mobilization. Our findings demonstrate that hormonal regulation by serotonin, in cooperation with the autonomic nervous system, regulates tear secretion.

Microwave-assisted pyrolysis of Mediterranean forest biomass waste: Bioproduct characterization

Different types of forest and scrub biomass waste that are representative of the Mediterranean biogeographical region (Pinus pinaster, Quercus ilex, waste from forestry activities in pinewoods and Cistus ladanifer) were pyrolyzed in a batch microwave reactor. The pyrolysis conditions were optimized using Pinus pinaster as the raw material. All experiments were performed at 400W with 7.5% biochar as a microwave absorber. Under these conditions four fractions were characterized: a non-condensable gas fraction, a bio-liquid composed of separable organic and aqueous soluble components and biochar. All liquid and gas fractions were characterized by gas chromatography/mass spectrometery (GC/qMS) to identify the main components. The bioliquid organic fraction was distilled and a bio-bitumen residue was collected. The rheological properties of this residue were studied. Biochar was characterized by measuring the specific surface area in order to assess its adsorptive properties. Mass distribution was calculated according to the feedstock.

Two new ways to get proteins into cells

Proteins can be important therapeutics, but in many cases their potential is limited because their polarity and large size prevent them from traversing cell membranes and entering cells, where their molecular targets may be located. Cell-penetrating peptides can shepherd proteins into cells, but in many cases the proteins are taken up by and retained in cell endosomes and thus still don’t reach the cytosol, the aqueous component of the cytoplasm. Two groups have now devised novel methods for getting proteins into the cytosol. Shiroh Futaki of Kyoto University and coworkers treat cells with an antibody and a peptide derivatized with an acidic group (Nat. Chem. 2017, DOI: 10.1038/nchem.2779). The pair enter an endosome, but the peptide disrupts the endosome’s negatively charged membrane, releasing the antibody. And Henry D. Herce and M. Cristina Cardoso of the Technical University of Darmstadt, Dominik Schumacher and Christian P. R. Hackenberger of Leibniz Institute for

Nanocomposite biomimetic vesicles based on interfacial complexes of polyelectrolytes and colloid magnetic nanoparticles

Development and study of novel biomimetic and biocompatible functional nanofilm structures, surfaces and colloid membranous vesicles are currently important from fundamental and applied viewpoints. They can serve as model systems for insight into the basic structural-functional interconnections and physicochemical mechanisms at the nano-scale in biomembranous systems, and are useful for development of engineering solutions efficient for bio-medical applications including controlled drug delivery. We present here the results of a study of novel nanofilm composite structures (Langmuir monolayers, Langmuir-Blodgett films and liposomes) based on the interfacial complexes formed by biogenic lipid phosphatidylcholine, synthetic amphiphilic water-insoluble polyamine stearoylspermine (a derivative of biogenic polyamine spermine and stearic acid), colloid cationic ligand-free magnetite nanoparticles and polyanions (DNA, Poly(styrenesulfonate)). It was found that stearoylspermine molecules formed stable Langmuir monolayer on an aqueous subphase surface and that monolayer compression isotherm changed as a result of interactions of the stearoylspermine monolayer with aqueous subphase components (colloid cationic magnetite nanoparticles and polyanions). Monolayer Langmuir-Blodgett films of interfacial polycomplexes formed by stearoylspermine and magnetite nanoparticles or DNA molecules were deposited onto the mica substrate surface and the structure of polycomplex films was investigated using AFM. The data obtained using Langmuir monolayer technique were further used in formation of new composite nanofilm magnetic colloidal membranous vesicles based on the interfacial polycomplexes of phosphatidylcholine, stearoylspermine, magnetite nanoparticles and polyanions. The nanocomposite membranous vesicles were prepared successfully by sequential adsorption of colloid cationic ligand-free magnetite nanoparticles and polyanions onto the cationic surface of mixed phosphatidylcholine/stearoylspermine liposomes preliminarily formed using conventional ultrasound method. The formed vesicles were characterized by transmission electron microscopy, AFM, electron magnetic resonance technique, laser light scattering and electrophoresis techniques. The synthesized stable biocompatible nanocomposite magnetic liposomal vesicles can be useful in development of novel efficient systems for capsulation, targeted transport, controlled spatial localization and physical stimuli-addressed drug and DNA delivery.

Influence of crosslinked alginate on drug release from highly concentrated emulsions

Biocompatible water-in-oil (W/O) and oil-in-water (W/O) highly concentrated emulsions (HIPREs) have been formed at 25°C, in systems consisting of aqueous component/castor oil derivative surfactant/oil compound. In both kinds of emulsions the concentration of internal phase was 83% and the aqueous component consisted of water, 1% sodium alginate solution or a mixture of sodium alginate solution and calcium chloride solution (crosslinked calcium alginate). Ketoprofen (KP) or clindamycine hydrochloride (CH) were solubilized in both kinds of HIPREs and the influence of the composition of the aqueous phase on drug release was studied. Droplet sizes of the W/O HIPREs formed were in the nanometric range, being smaller than other HIPREs described in the literature. Dynamic viscoelastic measurements showed an increase in the elastic modulus (G’) of the emulsions in the presence of alginate or crosslinked alginate. The influence of the order of incorporation of alginate and calcium chloride on the viscosity was demonstrated, as an indication of crosslinking efficiency. KP release to a PBS receptor solution was slower when crosslinked alginate was formed in the internal phase of W/O HIPREs. In contrast, the influence of crosslinked alginate on the release of CH was negligible and the solubility of the drug in the disperse phase demonstrated to be the main mechanism responsible of CH diffusion. The results obtained suggest that the formation of a crosslinked alginate matrix in the internal phase of HIPREs is a factor that has to be taken into account in the development of controlled drug delivery systems.

Sensory Evaluation and Oxidative Stability of a Suncream Formulated with Thermal Spring Waters from Ourense (NW Spain) and Sargassum muticum Extracts

The purpose of this work was to evaluate four thermal spring waters from Ourense and a Sargassum muticum extract as cosmetic ingredients for the preparation of a suncream. The thermal spring waters were tested for their suitability as an aqueous phase main component, and the algal extract was added as an antioxidant instead of using synthetic preservatives in the cosmetic formula. The emulsion was tested for lipid oxidation during a period of 9 months and for consumer acceptance by performing a sensory test on controls and blanks. Further, color parameters were considered, and a pH determination was performed. The S. muticum extract protected from primary and secondary oxidation as efficiently as Fucus sp. or α-tocopherol extracts. In addition, the sensorial test revealed that consumers preferred suncreams prepared with the S. muticum extract and with thermal spring water from O Tinteiro and A Chavasqueira. The pH of the suncreams varied with the selection of the ingredients, and no oscillations in colorimetric values were visually observed. Our results indicate that the algal extract and the thermal spring waters from Ourense are potential cosmetic ingredients, since they showed effectiveness as antioxidant ingredients, and the suncreams were well accepted by consumers.

Geochemical impact of injection of Eagle Ford brine on Hosston sandstone formation—Observations of autoclave water–rock interaction experiments

This study investigates water–rock interactions induced by brine injection into the Cretaceous clastic Hosston Formation in South Central Texas, a potential host formation for disposal of produced water from the Eagle Ford Shale during oil and gas extraction. The primary objectives of this experimental study were to (1) predict the geochemical reactions between the injected brine and the host formation during disposal operation, and (2) assess potential impact on flow properties of the host rock. The results provide important information of potential impact to injectivity and available methods to alleviate the problems if they occur during brine disposal. Five batch autoclave experiments were conducted to react an argillaceous sandstone of the Hosston Formation with a series of synthetic brines and the Eagle Ford brine for 3 weeks at 193 bar and 80 °C. To better identify mineral dissolution and precipitation, rock samples were ion-milled and examined using scanning electron microscopy (SEM) before and after the experiments. For each experiment, approximately 15 aqueous samples were taken with increasing time intervals from hours to days. Dissolution of anhydrite, which results in a rapid increase of SO4 and Ca concentrations in the solution of ∼500 ppm and ∼200 ppm respectively, is the most significant reaction. Small amounts of dolomite and K-feldspar were also dissolved to release Mg, Ca, K, and Si. Small amounts of iron hydroxides and kaolinite precipitated. Geochemical modeling is able to reproduce the behavior of the major aqueous components and of the observed mineral dissolution and precipitation. Overall, change in flow properties from the water–rock interaction is insignificant: mercury intrusion capillary pressure (MICP) data show little difference in porosity, permeability, and pore-throat-size distribution between the pre- and post-experiment samples. This study suggests that injection of Eagle Ford brine into the Hosston Formation will pose minimum risks for the brine disposal operation.

Sources and behaviour of nitrogen compounds in the shallow groundwater of agricultural areas (Poyang Lake basin, China)

Nitrogen contamination of natural water is a typical problem for various territories throughout the world. One of the regions exposed to nitrogen pollution is located in the Poyang Lake basin. As a result of agricultural activity and dense population, the shallow groundwater of this area is characterised by a high concentration of nitrogen compounds, primarily NO3−, with the concentration varying from 0.1mg/L to 206mg/L. Locally, high ammonium content occurs in the shallow groundwater with low reduction potential Eh (<100mV). However, in general, the shallow groundwater of the Poyang Lake basin has Eh>100mV. To identify sources of nitrogen species and the factors that determine their behaviour, the dual stable isotope approach (δ15N and δ18О) and physical-chemical modelling were applied. Actual data were collected by sampling shallow groundwater from domestic water supply wells around the lake. The δ18О values from −4.1‰ to 13.9‰ with an average value of 5.3 permille indicate a significant influence of nitrification on nitrogen balance. The enrichment of nitrate with the 15N isotope indicates that manure and domestic sewage are the principal sources of nitrogen compounds. Inorganic nitrogen speciation and thermodynamic calculations demonstrate the high stability of nitrate in the studied groundwater. Computer simulation and field observations indicate the reducing conditions formed under joint effects of anthropogenic factors and appropriate natural conditions, such as the low-level topography in which decreased water exchange rate can occur. The simulation also demonstrates the growth in pH of the groundwater as a consequence of fertilisation, which, in turn, conduced to the clay mineral formation at lower concentrations of aqueous clay-forming components than the ones under the natural conditions.

Assessing Biomineral Formation by Iron‐oxidizing Bacteria in a Circumneutral Creek

AbstractIron oxidizing bacteria and environmental conditions influence the formation of iron biominerals in aquatic environments. This 10‐week Research Experience for Undergraduates (REU) study focused on elucidating how water chemistry and iron oxidizing bacteria affect the formation of iron oxides in creeks with circumneutral pH. Two locations, each with multiple microenvironments containing abundant iron oxide deposits, were studied. Water chemistry was assessed via both in situ and laboratory analysis over a 5‐week period, revealing correlations between aqueous components that indicate differing groundwater sources may feed nearby discharge points. Microscopy of iron oxide deposits reveals morphologies consistent with the presence of iron oxidizing bacteria. Although efforts to isolate iron oxidizing bacteria did not produce pure cultures, 16S ribosomal DNA analysis also suggests the presence of iron oxidizing bacteria in these sites. Taken together, these results show the diversity of iron oxide forming microenvironments in spatially collocated sites, which may result in unique formations of iron oxide structures, microbial communities, and aqueous chemical cycling.

Textural, Fluid Inclusion, and Stable Oxygen Isotope Constraints on Vein Formation and Gold Precipitation at the 007 Deposit, Rice Lake Greenstone Belt, Bissett, Manitoba, Canada

The 007 gold deposit is located within the 2.99–2.70 Ga Rice Lake greenstone belt, Manitoba, Canada. Auriferous quartz-ankerite veins (± albite ± sericite ± chlorite) contain early, coarse-grained, barren quartz (Q1) and secondary, finer grained quartz (Q2). The latter occurs as polycrystalline “ribbons” and microveinlets hosted along Q1 grain boundaries that formed by dynamic recrystallization of Q1, and later dissolution-reprecipitation, respectively. Deposition of electrum (65–86 at. % Au) postdated Q1 formation and was broadly syngenetic with Q2 formation. Electrum occurs in two forms: (1) along sutured (healed, recrystallized) and partially sutured grain boundaries representing dissolution-reprecipitation surfaces between adjacent Q2 grains in association with coeval sericite and ankerite, and (2) as inclusions coeval with Au-Ag-Ni-Pb tellurides hosted within pyrite grains coeval with Q2 and secondary ankerite and sericite. Pyrite trace element mapping (by LA-ICP-MS) displays complex metal zonation indicating significant variations in the availability of metals during various stages of pyrite formation. Mapping of trace elements in pyrite shows that there were two Au precipitation events, one coeval with Zn, In, Sn, Cd, Ag, and Te enrichment in the cores of pyrite and another fracture-controlled stage coeval with Ag, As, Se, Pb, Bi, Ni, and Co enrichment. Four distinct types of fluid inclusions are identified in quartz: (1) type 1 aqueous-carbonic inclusions (H2O-NaCl-CO2 ± CH4 ± N2) hosted throughout Q1 quartz with a range in the melting point of CO2 ![Formula][1] from −59.6° to −56.6°C due to minor and variable CH4 (≤1.4 mol %) and N2 (≤1.7 mol %) in the carbonic phase, salinities from 4.1 to 9.7 wt % NaCl equiv, and total homogenization (ThTOT) between 278° and 346°C to the liquid phase; (2) type 2 carbonic inclusions with a minor aqueous component (CO2 ± CH4 ± N2 ± H2O-NaCl) hosted along Q1-Q2, and Q2-Q2 grain boundaries; ![Formula][2] in these inclusions ranges from −58.0° to −56.6°C due to minor CH4 and N2 in the carbonic phase; (3) type 3 aqueous inclusions with a minor carbonic component (H2O-NaCl ± CO2 ± CH4 ± N2) that are hosted along Q1-Q2 and Q2-Q2 grain boundaries; these inclusions show a range in salinity (4.0–12.4 wt % NaCl equiv) similar to type 1 inclusions and have ThTOT between 273° and 315°C; and (4) type 4 aqueous inclusions (H2O-NaCl) that occur in secondary trails crosscutting (i.e., postdating) Q1 and Q2 domains and grain boundaries; these inclusions are more saline (14.8–17.5 wt % NaCl equiv) than type 1 and 3 inclusions. Importantly, whereas type 1 inclusions were trapped during the growth of Q1 (prior to gold deposition), the common occurrence of texturally coeval type 2 and 3 inclusions and electrum along Q1-Q2 and Q2-Q2 grain boundaries suggests that these fluids are likely related to gold deposition. In situ oxygen isotope analysis of barren Q1 and auriferous Q2 shows large inter- and intra-grain variations in composition. These variations in δ 18O and the corresponding temperature-dependent δ 18OH2O values for the fluids that equilibrated with Q1 (−3.7 to +6.8‰) and Q2 (−3.3 to +8.4‰) are not the consequence of fluid mixing. Rather, grain-scale δ 18O variation may have involved Rayleigh fractionation within the veins if they are considered to have acted as a partially closed system rather than a continuously open and replenished flow-through system. An approximate P-T window of gold deposition is constrained using fluid inclusion microthermometry for type 2 and 3 inclusions (trapped synchronous to gold precipitation), combined with the relevant stability boundaries for Au-Ag-Te phases that occur as inclusions in texturally coeval pyrite. The maximum conditions for gold precipitation are ~1 kbar and 320°C. Differences between minimum Ptrapping and Ttrapping for pre-gold fluids (type 1 inclusions) and maximum Ptrapping and Ttrapping for syn-gold fluids (types 2 and 3) suggest that immiscibility was responsible for gold deposition and occurred due to significant fluctuations in pressure (>1 kbar) but with neglegible cooling from the barren Q1 to the auriferous Q2 stage. [1]: /embed/mml-math-1.gif [2]: /embed/mml-math-2.gif

Specific process features of epoxidation of fatty acid methyl esters of vegetable oils with performic acid generated in situ

Physicochemical relationships of the phase distribution of the reactants in epoxidation of fatty acid methyl esters of vegetable oils with performic acid generated in situ were determined.. The progress of epoxidation is accompanied by redistribution of the organic and aqueous phase volumes. The major cause of changes in the phase volumes is the transfer of peroxide oxygen from the aqueous phase into the organic phase upon formation of epoxy groups. A comparable change in the phase volumes is due to reactive extraction of aqueous phase components with the epoxy compounds formed.

Stability of Mixed Preparations Consisting of Commercial Moisturizing Creams with an Ointment Base Investigated by Magnetic Resonance Imaging.

A moisturizing cream mixed with a steroid ointment is frequently prescribed to patients suffering from atopic dermatitis. However, there is a concern that the mixing operation causes destabilization. The present study was performed to investigate the stability of such preparations closely using magnetic resonance imaging (MRI). As sample preparations, five commercial moisturizing creams that are popular in Japan were mixed with an ointment base, a white petrolatum, at a volume ratio of 1 : 1. The mixed preparations were stored at 60°C to accelerate the destabilization processes. Subsequently, the phase separations induced by the storage test were monitored using MRI. Using advanced MR technologies including spin-spin relaxation time (T2) mapping and MR spectroscopy, we successfully characterized the phase-separation behavior of the test samples. For most samples, phase separations developed by the bleeding of liquid oil components. From a sample consisting of an oil-in-water-type cream, Urepearl Cream 10%, a distinct phase-separation mode was observed, which was initiated by the aqueous component separating from the bottom part of the sample. The resultant phase separation was the most distinct among the test samples. To investigate the phase separation quantitatively and objectively, we conducted a histogram analysis on the acquired T2 maps. The water-in-oil type creams were found to be much more stable after mixing with ointment base than those of oil-in-water type creams. This finding strongly supported the validity of the mixing operation traditionally conducted in pharmacies.