Inclusion Of NaCl Research Articles

Thermal responsive sodium alginate/polyacrylamide/poly (N-isopropylacrylamide) ionic hydrogel composite via seeding calcium carbonate microparticles for the engineering of ultrasensitive wearable sensors

The design of polyelectrolyte hydrogel with unique tensile and adhesive properties which can be applied across disciplines has gradually become a popular trend. However, the phenomenon of global warming and the emergence of extreme weather, it still faces some urgent problems that should be solved, such as the optimal utilization of polyelectrolyte hydrogel across a wide range of temperatures. Herein, a wide temperature sensitivity and conductivity hydrogel based on sodium alginate, acrylamide and N-isopropylacrylamide was constructed, which exhibited excellent adhesion and temperature conductivity. It is worth noting that after the inclusion of CaCO3 and NaCl in the hydrogel, the hydrogel showed excellent tensile properties (fracture strain >2000 %). Within a wide temperature range (−15–50 °C), it exhibits exceptional electrical conductivity (2.75 S ∗ m−1) and sensitivity (GF = 8.76 under high strain). This innovative intelligent polyelectrolyte hydrogel provides suitable strategy for flexible sensors, smart wearable devices and medical monitoring equipment.

Thermally induced phase separation PVDF membrane fabricated by using NaCl coagulation bath: Relation of membrane surface morphology and permeation performance

Efforts have been made in thermally induced phase separation (TIPS) process to modify the morphology of polyvinylidene fluoride (PVDF) membranes in order to improve their permeation performance and mechanical properties. Nevertheless, many methods not only altered the outer surface but also impacted the overall membrane structure, resulting in a trade-off between permeability and mechanical properties. In this study, we utilized a modified TIPS process to refine the outer surface morphology without altering the bulk structure. This was achieved by introducing NaCl in the coagulation bath. The PVDF membranes were fabricated using a dope with water insoluble diluent dimethyl phthalate (DMP) as main solvent and water-soluble additives polyethylene glycol 400 (PEG400)/triethylene glycol (TEG) as pore formers. The inclusion of NaCl in the coagulation bath serves to decrease the solubility of PEG within this medium, owing to the salting-out effect. Consequently, the NaCl concentration in the coagulation bath emerges as a crucial factor in regulating the migration of PEG400 toward the membrane surface. This control mechanism facilitates the precise adjustment of the outer surface morphology in the fabrication of membranes. As the NaCl concentration increases in the coagulation bath, the outer surface of the fabricated membrane transited from a mesh-like structure to a spherulite structure. As 0.5 mol L−1 NaCl was added to the coagulation bath, the membranes displayed a pure water permeability of 1073.9 L m−2 h−1 bar−1 while maintaining a narrow pore size distribution. Compared to the membranes fabricated without NaCl addition, the increment of the PWP contributed to the slight increase in mean pore size from 65 nm to 84 nm. Meanwhile, the water-insoluble diluent DMP was not affected by the addition of NaCl, which means that the bulk structure of the membrane could be maintained. Consequently, the increase in permeability did not compromise the mechanical properties of the membranes. All the membranes fabricated in this study maintained a reasonable tensile strength of approximately 3 MPa. This study introduces a simple and environmental method to increase the permeability effectively and fine-tune the pore size of the TIPS membranes while having little effect on the bulk structure. Furthermore, the study provides valuable insights into how changes in outer surface morphology can impact the pore size and permeability of TIPS PVDF membranes.

Influence of volume expansion in NaCl crystallization on the physical properties and molecular structure of asphalt: A MD simulation study

The pavement damage caused by salt-induced volume expansion is becoming increasingly noticeable. Molecular dynamics (MD) method was applied to evaluate the effects of varied volumes of NaCl crystals on physical properties and structure of asphalt. The effects of NaCl crystals on the compatibility between styrene–butadiene–styrene triblock copolymer (SBS) and asphalt, as well as the influence of SBS on the diffusion coefficient of NaCl crystals in the asphalt system, were investigated alongside their effects on the physical modulus and molecular structure of asphalt. The results show that the solubility parameter of the asphalt blends decreases as the volume of NaCl crystals increases. Specifically, the solubility parameter decreases by 52.5 % for the biaxial crystalline growth of NaCl and asphalt blends compared to the matrix asphalt. The analysis of the ion diffusion coefficient reveals that the primary disruption of NaCl crystals in asphalt blends is due to early Cl- and late Na+ diffusion. Furthermore, the rise in shear modulus of the asphalt blends suggests that the salt erosion process of SBS-modified asphalt is advantageous for its high temperature and shear resistance. The changes in peak radial distribution function and radius of gyration indicate that the inclusion of NaCl and SBS into asphalt is a physical aging process. In this case, SBS incorporation acts as a reinforcement to the asphalt to retard the erosion of NaCl.

Antioxidant activity enhancement and oxidative damage inhibition by Lagenaria breviflora fruit and Xanthosoma sagittifolium corm in hypertensive Wistar rats.

Cardiovascular diseases are the leading causes of mortality in the world today with hypertension being the major clinical presentation of these diseases. This study assessed the anti-hypertensive effects of Lagenaria breviflora whole fruit and Xanthsoma sagittifolium corms in experimentally inudced hypertensive Wistar rats. The ability of the plants to ameliorate oxidative damage accompanying hypertension was evaluated using changes in oxidative stress markers as well as monitoring of cardiovascular parameters. Hypertension was induced by intraperitoneal injection of DOCA salt twice weekly and daily inclusion of NaCl (1%) in drinking water. Methanol extracts of L.breviflora or X. sagittifolium was administered to hypertensive rats for 35 days and the outcome was compared to hypertensive rats administred with lisinopril or hydrochlorothiazide and a group of normotensive rats (control). Systolic, diastolic and mean arterial pressures were determined on day 34 and blood sample collected on day 35. The rats were thereafter humanely sacrificed, and organs were harvested. This study showed that the extracts lowered blood pressure, free protein thiols but increased toal protein, gluthathione peroxidase, reduced glutathione, glutathione S-transferase, catalase and nitric oxide in the heart, kidney and liver compared to untreated hypertensive rats. However, malondialdehyde levels and hydrogen peroxide activities were reduced. L. breviflora fruit and X. sagittifloium corm exhibited antihypertensive properties and ameliorate oxidative damage associated with hypertension by enhancing the antioxidant defense sysyem and inhibiting generation of free radicals.

Reversal of Hypertension and Amelioration of Oxidative Stress by Persea americana and Allium sativum in Experimentally-Induced Hypertensive Wistar Rats

Aim: This study evaluated the antihypertensive and antioxidant effects of hexane, ethyl acetate and methanol extracts of Persea americana and Allium sativum in experimentally-induced hypertensive Wistar rats.
 Study Design: Experimental Research. 
 Place and Duration of Study: Department of Veterinary Pharmacology and Toxicology, University of Ibadan (Animal House), between May 2019 and December 2019.
 Methodology: The experiment was carried out in 85 rats randomly divided into 17 groups. Group 1 were normotensive rats while hypertension was induced in groups 2-16 by unilateral nephrectomy and inclusion of NaCl (1%) in drinking water. Group 17 had abdominal incision without nephrectomy (sham). Treatment groups were administered P. americana or A. sativum extracts at 20 mg/kg or 50 mg/kg dose and standard antihypertensives; lisinopril or hydrochlorothiazide.
 Results: Results of the experiment showed treatment of hypertensive rats with 50 mg/kg of A. sativum hexane and P. americana methanol extract caused the most significant decrease in blood pressure compared to normotensive rats. Various extracts of these two plants elevated antioxidants levels (GPx, GST, GSH and SOD) in the brain, heart, kidney and liver significantly while H2O2 and MDA were significantly decreased compared to untreated hypertensive rats. NO, an important neurotransmitter for normal endothelial function was also restored in the extract-treated rat, as a deficiency contributes greatly to the development of hypertension.
 Conclusion: The study concluded that P. americana and A. sativum do not only lower blood pressure. The plants also inhibited generation of free radicals by enhancing the antioxidant system and mopped up generated free radicals demonstrated by decline in H2O2 and MDA levels. These plants have been shown in this study to contain potential drug candidates which can be proposed for treatment of hypertension.

Increasing the Hydrophobic Component of Poloxamers and the Inclusion of Salt Extend the Release of Bupivacaine from Injectable In Situ Gels, While Common Polymer Additives Have Little Effect.

Various strategies have been applied to reduce the initial burst of drug release and sustain release from poloxamer-based thermoresponsive gels. This work focussed on investigating different formulation approaches to minimise the initial burst of release and sustain the release of the small hydrophilic drug bupivacaine hydrochloride from poloxamer-based thermoresponsive gels. Various in situ gel formulations were prepared by varying the polypropylene oxide (PPO)/polyethylene oxide (PEO) ratio and by adding additives previously described in the literature. It was observed that increasing the PPO/PEO ratio from 0.28 to 0.30 reduced the initial burst release from 17.3% ± 1.8 to 9.1% ± 1.2 during the first six hours and extended the release profile from 10 to 14 days. Notably, the inclusion of sodium chloride (NaCl 0.4% w/w) further reduced the initial burst release to 1.8% ± 1.1 over the first 6 h. Meanwhile, physical blending with additive polymers had a negligible effect on the burst release and overall release profile. The findings suggest that extended release of bupivacaine hydrochloride, with reduced initial burst release, can be achieved simply by increasing the PPO/PEO ratio and the inclusion of NaCl.

Short communication: Sodium chloride levels in pacu (Piaractus mesopotamicus) fingerling feeds free of fish meal

Aim of study: To evaluate the effects of increasing NaCl levels on the zootechnical performance of pacu fingerling. Area of study: The experiments were conducted at the Aquatic Organism Production and Reproduction Systems Laboratory belonging to the Federal University of Paraná (UFPR), in the Palotina Sector, Paraná Estate, Brazil. Material and methods: Seven hundred and fifty fingerlings with an average weight of 3.41 ± 0.09 g were distributed in circular boxes, in a completely randomized design consisting of six treatments and five replications. Treatments comprised soybean- and maize-based diets containing increasing levels of NaCl (0.00, 0.25, 0.50, 0.75, 1.00 and 1.25%). The experiments were conducted for 50 days. At the end of the experimental period the fish were fasted for 24 hours, anesthetized, weighed and measured to calculate zootechnical performances. Performance data were subjected to an analysis of variance followed by Tukey’s test when significant differences were found between the means (p<0.05). Main results: The influence (p<0.05) of dietary NaCl levels on final weight, feed intake, apparent feed conversion, specific growth rate, average weight gain, clean trunk production, head carcass yield, headless carcass yield, feed intake and survival was assessed. The results indicate that non-salt treated fingerlings along with the 0.25% salt inclusion treatment led to better feed use, as evidenced by apparent feed conversions of 1.64 and 2.02, respectively. Research highlights: The inclusion of NaCl in pacu fingerling soybean and maize-based diets is not recommended.

One-part hybrid cements from fly ash and electric arc furnace slag activated by sodium sulphate or sodium chloride

An innovative hybrid cement, based on type F fly ash (FA), iron and steel slag (ISS) and Portland cement (OPC), is proposed in the present paper. The precursors were activated by powder-form elements – sodium sulphate or sodium chloride – forming what is known as a ‘one part geopolymer’ cement, which was then evaluated considering both mechanical and microstructural perspectives. Results showed that, in these conditions, the reactivity of the ISS is lower than that of the FA, with or without the presence of the activators. In the ternary pastes formed by 50%ISS +25%FA + 25%OPC and 25%ISS +25%FA + 50%OPC, with no activator included, both the ISS and the FA reacted due to its inherent pozzolanic activity. The presence of the powder-form activators increased the mechanical strength of the pastes (which are known as “hybrid cements”, since an activator and OPC are simultaneously present), relatively to the no-activator pastes. Furthermore, the inclusion of Na2SO4 or NaCl increased and decreased the activation rate, respectively, relatively to the equivalent binder hydrated with water (i.e. without the presence of an activator). Regardless, in both cases, strength values above 40 MPa and 35 MPa, after 28 days curing, were obtained. In the hybrid cements, the activators first reacted with the OPC phases; with the activator anions originating products such as calcium sulphate, ettringite or Friedel's salt (depending on the activator type), which increase the density of the matrix and, therefore, the resulting mechanical strength. Furthermore, in the presence of the Na+ cation, local NaOH is generated, increasing the alkalinity of the medium and, consequently, accelerating the reaction of the ISS and FA, which further improves the mechanical strength. Behind every combination, a C-(A)-S-H gel is the main reaction product.

Geological and geochemical characterization of the Nanlia and Makorongo gold prospects, Mozambique Belt, northeastern Mozambique

Northern Mozambique hosts numerous occurrences of gold mineralization in metamorphic terranes, which are little known because of the insufficient studies. In this work, we describe the main geological and geochemical characteristics of the Nanlia and Makorongo gold prospects located in the Namuno district, northeastern Mozambique. We report the mode of occurrence of gold, petrography and mineralogy of the host rocks and ores, fluid inclusion characteristics and stable isotope data, to understand the genesis of gold mineralization in the study area. The gold mineralization in the Nanlia and Makorongo prospects is hosted by the Neoproterozoic Xixano Metamorphic Complex in the Mozambique Belt, which is composed of mafic granulite, amphibolite, paragneiss and marble. The host rock amphibolite consists mainly of amphibole, plagioclase, biotite and minor quartz, titanite and sulfides. The gold mineralization is associated with E-W to ENE-WSW trending quartz veins, oriented parallel to low angle to the foliation of the host rock amphibolite. The ore mineralogy consists of pyrite, pyrrhotite, chalcopyrite, magnetite, galena and sphalerite, with minor tellurides, xilingolite, electrum and native gold. Mineralized quartz veins in the Nanlia and Makorongo prospects host two types of fluid inclusions which locally coexist in the same assemblage: type 1, one-phase CO2 inclusions with final melting temperature between −58 and −52 °C; and type 2, two-phase H2O + NaCl (±CO2 ± N2 ± CH4) inclusions with homogenization temperature ranging from 246 to 370 °C and 239 to 382 °C in the Nanlia and Makorongo prospects, respectively, and salinity of 12–21 wt% NaCl eq. Pressure and temperature (P-T) conditions of ore-formation were estimated from fluid inclusions and sphalerite geobarometry at 420–620 °C and 160–280 MPa, and 330–440 °C and 150–200 MPa in the Nanlia and Makorongo prospects, respectively. The Nanlia and Makorongo gold prospects are classified as orogenic-type gold deposits. We suggest that gold mineralization was caused by an aqueous-carbonic fluid with low-moderate salinity originated by devolatilization during prograde metamorphism of underlying rocks. The gold mineralization post-dates the peak of metamorphism of the host rocks, thus formed during the retrograde metamorphism of the host rocks. The precipitation of gold in the Nanlia and Makorongo prospects was caused by fluid phase separation induced by pressure drop as the mineralizing fluid migrated to shallower depths.

Effect of common salt (NaCl) on reproductive tract dimension, haemolymph haemocyte count and biochemical parameters of Giant African Land snail (A. marginata) during dry season

A study was conducted on the effect of common salt (NaCl) on reproductive tract dimension, haemolymph haemocyte count and biochemical parameters of Giant African Land snail (GALs), Archachatina marginata during the dry season. Forty (40) snails with a weight range of 150 g–180 g were used for this study. Four (4) treatment with each consisting of ten (10) replicates were assigned as follows: T1 (Control: concentrate +0 g of salt (NaCl)), T2 (concentrate +0.05 g of salt (NaCl)), T3 (concentrate+0.15 g of salt (NaCl) and T4 (concentrate + 0.25 of salt (NaCl)). The experiment lasted 13 weeks. Haemolymph was collected at the end of 13 weeks to assess haemocyte count, total protein, albumin, globulin, alanine transaminase (ALT) and aspartate transaminase (AST). The haemocyte count was determined using a Neubeur haemocytometer, while haemolymph biochemical parameters were determined using spectrophotometric methods with the appropriate kit. The snails were also dissected for complete isolation of the reproductive tract for morphometric measurements. Key organs concerned were: Ovo-testis, albumen, little hermaphrodite duct and hepatopancreas. The weight and length of each of these organs were taken together with complete tract weight. Ovo-testis from each treatment was also harvested for histology. A mortality record was taken as the experiment progresses. The result showed that serum biochemical parameters were not significantly (P > 0.05) affected by a various inclusion level of salt used. But it had a significant effect on ovotesis length, albumen weight, little hermaphrodite weight and reproductive tract weight. However, no significant effect was seen in ovotestis weight, albumen length, little hermaphrodite length and hepatopancreas weight and length. It was also discovered that common salt (NaCl) significantly affected (P < 0.01) haemocyte count and mortality record of GALS. Snails fed 0.25 g NaCl had the highest haemocyte count, followed by those fed 0.15 g, while snails fed 0 g and 0.05 g recorded the least value. It was also discovered that 0 g NaCl inclusion into the diet of snail (A. marginata) recorded the highest mortality (60 %) followed by 0.05 g NaCl inclusion level which gave 30 % mortality. However, the inclusion level of 0.15 g and 0.25 g NaCl into snail feed recorded no mortality. Histological evaluation of the ovotestis revealed that snail given 0.25 g inclusion into the concentrate diet had active acini with spermatogonium and well-formed oocyte, followed by those group with 0.15 g with active acini with several ova. It is obvious from this study that NaCl had an immune-modulatory influence on GAS during the dry season via mitigation of mortality without negatively affecting the haemolymph biochemical parameter. Inclusion used in this study also boost reproductive apparatus functions which are usually not active during this period. It is therefore recommended that both 0.15 g and 0.25 g/kg be included into the diet of A. marginata during the dry season to mitigate challenges that confront snail farming during the period to boost production and reduce economic losses due to mortality during this season.

Modifying the figure of merit of thermoelectric materials with inclusions of porous structures

The overall investigation of devices when it comes to the transformation of heat flux into electrical power, and electrical energy to heat power, significantly involves thermoelectric devices (TEDs). These devices provide the potential to build clean energy using a combination of appropriate materials. It has been recognized that more than 60% of the energy generated worldwide disappears, frequently due to the heat involved (exothermic reactions, friction, combustion, and radiation). Economically feasible TED materials and devices have not been successfully developed for larger-scale industrial use due to their low efficiency, unreliability, and high cost of materials and manufacturing. In this study, simple and inexpensive materials and methods were used to tailor the properties of thermoelectric materials to improve their figure of merit, which may be of great potential for meeting future energy demand. Stoichiometric bismuth telluride (Bi2Te3) powder was compounded with numerous concentrations of sodium chloride (NaCl) salt particles ranging from 0 to 50% by volume. The NaCl was ground to microscale particles, and cylindrical pellets were crafted using cold pressing and sintering operations. Consequently, the NaCl was leached separately within the samples using hot water, which caused porous structures. Testing equipment was designed to measure the three essential parameters of TEDs—electrical conductivity, Seebeck coefficient, and thermal conductivity—before and after the NaCl leaching process. Following that, the figure of merit was also calculated for each concentration. Primarily porous structures containing 20% NaCl had a 37.55% higher figure-of-merit value compared to the base samples (0% NaCl), and an increase of 89.07% in the figure of merit from the solids content of the samples was observed with NaCl inclusions at a concentration of 30% by volume. The existence of both NaCl and pores was sufficient to increase the figure of merit. Inclusions and porosity detrimentally influenced the electrical conductivity, but there was a substantial rise in the Seebeck coefficient and thermal conductivity changes leading to an increase in the figure of merit. The figure of merit obtained from this study is relatively moderate for the latest generation of thermoelectric materials. However, the materials and methods used here were simple, economical, and scalable and have great potential for use with optimized thermoelectric materials in hopes of further improvement in the figure of merit.

Fat Inclusion Level, NaCl Content and LAB Starter Cultures in the Manufacturing of Italian-Type Ostrich Salami: Weight Loss and Nutritional Traits

The experiment studied the effect of two different fat inclusion levels (30% and 40%), NaCl contents (2.4 and 2.6%) and starter cultures (lactic acid bacteria (LAB) 6: L. curvatus/S. xylosus; LAB 8: L. sakei/S. xylosus) on the weight loss and nutritional composition of Italian-type ostrich salami. With this purpose, 8 batches of 9 salami each (n = 72) were prepared. Salami were ripened for 20 weeks: weight loss was monitored throughout the experiment, while salami nutritional composition was evaluated at 10 and 20 weeks of ripening. The lowest fat and highest salt inclusion levels provided the highest cumulative weight loss throughout the trial. At 10 weeks of ripening, salami with 40% fat were the richest in moisture and fat, whereas the leanest ones had the highest protein, ash and cholesterol contents. LAB 6 provided salami with the highest moisture and protein, while LAB 8 increased fat and cholesterol contents. At 20 weeks of ripening the proximate composition of ostrich salami was solely affected by fat inclusion level, with similar findings to those observed at 10 weeks. Overall, fat inclusion level had a great impact on the weight loss and nutritional composition of Italian-style ostrich salami. Reducing the NaCl inclusion from 2.6% to 2.4%, the weight loss of ostrich salami was retarded by approximately 1 week, without affecting the nutritional composition of the final product. Results of the study suggested that it is feasible to produce salami with lower fat and salt contents, while ensuring satisfactory product quality.

Petrogenesis, Ore Mineralogy, and Fluid Inclusion Studies of the Tagu Sn–W Deposit, Myeik, Southern Myanmar

Most of the granite-related Sn–W deposits in Myanmar are located in the Western Granitoid Province (WGP) of Southeast Asia. The Tagu deposit in the southern part of the WGP is a granite related Sn–W deposit. The biotite granite is composed of quartz, feldspars (plagioclase, orthoclase, and microcline), and micas (muscovite and biotite) and belongs to S-type peraluminous granite. Abundances of large-ion lithophile elements (LILEs), such as Rb, K, and Pb, coupled with the deficiency of high-field-strength elements (HFSEs), such as Nb, P, and Ti, indicate that the parental magma for the Tagu granite was derived from the lower continental crust at syn-collisional setting. Mineralized veins consist of early-formed oxide ore minerals, such as cassiterite and wolframite, which were followed by the formation of sulfide minerals. Three main types of fluid inclusions were distinguished from the mineralized quartz veins hosted by granite and metasedimentary rocks: Type-A—two phases, liquid (L) + vapor (V) aqueous inclusions; Type-B—two phases, vapor (V) + liquid (L) vapor-rich inclusions; And type-C—three phases, liquid + CO2-liquid + CO2-vapor inclusions. Quartz in the veins hosted in granite corresponding with earlier deposition contains type-A, type-B, and type-C fluid inclusions, whereas that in the veins hosted in metasedimentary rocks corresponding with later deposition contains only type-A fluid inclusions. The homogenization temperatures of type-A inclusions range from 140 °C to 330 °C (mode at 230 °C), with corresponding salinities from 1.1 wt.% to 8.9 wt.% NaCl equivalent for quartz veins hosted in metasedimentary rocks, and from 230 °C to 370 °C (mode at 280 °C), with corresponding salinities from 2.9 wt.% to 10.6 wt.% NaCl equivalents for quartz veins hosted in granite. The homogenization temperatures of type-B vapor-rich inclusions in quartz veins in granite range from 310 °C to 390 °C (mode at 350 °C), with corresponding salinities from 6.7 wt.% to 12.2 wt.% NaCl equivalent. The homogenization temperatures of type-C H2O–CO2–NaCl inclusions vary from 270 °C to 405 °C (mode at 330 °C), with corresponding salinities from 1.8 wt.% to 5.6 wt.% NaCl equivalent. The original ascending ore fluid was probably CO2-bearing fluid which evolved into two phase fluid by immiscibility due to pressure drop in the mineralization channels. Furthermore, the temperature and salinities of two-phase aqueous fluids were later most likely decreased by the mixing with meteoric water. The salinities of the type-B vapor-rich inclusions are higher than those of the type-C CO2-rich inclusions, which may have resulted from CO2 separation from the fluids. The escape of gases can lead to an increase in the salinity of the residual fluids. Therefore, the main ore-forming mechanisms of the Tagu Sn–W deposit are characterized by fluid immiscibility during an early stage, and fluid mixing with meteoric water in the late stage at a lower temperature.

Ore genesis of the Baiyun gold deposit in Liaoning province, NE China: constraints from fluid inclusions and zircon U–Pb ages

The Baiyun gold deposit in the Liaodong gold province, NE, North China Craton (NCC), is a lode gold deposit hosted within the Paleoproterozoic metamorphic rocks. Disseminated and vein-hosted gold mineralization occurs along NWW-trending interlayer faults and NE-trending normal faults. Crosscutting relationships and mineral assemblages indicate hydrothermal process of the gold deposit can be divided into three stages, characterized by pyrite–quartz (stage 1), quartz–pyrite–chalcopyrite (stage 2), and quartz–carbonate (stage 3) assemblages. Gold is observed within stage 1 and 2 veins. Hessite is observed within stage 2 veins. Fluid inclusion petrography and microthermometry indicate that the ore fluid evolved from moderate salinities to low salinities, likely due to fluid mixing. The precipitation of gold and hessite is attributed to fluid mixing. Fluid inclusion compositions present the minimum trapping temperatures of the ore fluid were between 200 and 290 °C. Minimum trapping pressures estimated from H2O–CO2–NaCl inclusions were 58–139 and 24–68 MPa for stage 1 and 2 assemblages, respectively. The δ18Owater (‰ SMOW) values of ore fluid in stage 1 range from 3.9 to 7.8 ‰, and the δD (‰ SMOW) values are between − 92 and − 69‰, indicating that the ore fluid was dominantly magmatic water. Zircon from a pre-ore quartz porphyry yielded a weighted mean zircon 206Pb/238U age of 127.8 ± 0.8 Ma, and the emplacement of a post-ore microdiorite is constrained to 125.6 ± 1.3 Ma. These results suggest that the Baiyun gold deposit is an intrusion-related vein gold deposit formed at ~ 126 Ma, which coincides with extension and a peak in magmatism within the NCC, indicating that gold mineralization in this region might have resulted from the breakup of the NCC.

Fluid inclusion and stable isotope (O, H, C) constraints on the genesis of the Pedra Branca gold deposit, Troia Massif, Borborema Province, NE Brazil: An example of hypozonal orogenic gold mineralization

At the Archean-Paleoproterozoic Troia Massif, NE Brazil, two major Paleoproterozoic greenstone belts are documented (Algodões and Serra das Pipocas). They share similar lithostratigraphic characteristics with other 2.2–2.1 Ga greenstone belts of the surrounding cratonic domains (e.g. Guiana shield and West Africa craton). Gold mineralization in the Serra das Pipocas greenstone belt is associated with a regional NE-trending shear zone. In the mineralized area (the Pedra Branca gold deposit) the main gold mineralization is found in association with quartz veins, calc–silicate alteration (e.g. diopside, K-feldspar, amphibole, titanite, biotite, pyrite, albite, magnetite ± carbonates) and albitization. Pyrrhotite is commonly found as inclusions in pyrite, and late magnetite replaces pyrite, suggesting progressive oxidation of the ore–forming fluid. Free-milling gold commonly precipitates at the late stages of alteration, in close association with magnetite and tellurides. The main tellurides found are hessite, altaite, sylvanite, calaverite and tellurobismuthite. Two fluid inclusion assemblages were identified from mineralized quartz veins. Assemblage 1 is characterized by pseudo-secondary trails that show the coexistence of CO2–rich and low salinity (0–8 wt% NaCl equiv.) CO2–H2O–NaCl and H2O–NaCl inclusions, suggesting formation during phase separation (fluid immiscibility). Assemblage 2 is represented by late secondary low–temperature (Th < 200 °C) H2O–NaCl inclusions, probably unrelated to gold mineralization. The δ18O, δD and δ13C values of hydrothermal minerals (quartz, calcite, biotite, hornblende and magnetite) and fluid inclusions are compatible with a magmatic–hydrothermal ore-forming fluid that underwent fluid–rock interaction with the greenstone sequence. The calculated fluid δ18O values range from +8.3 to +11.0‰ (n = 59), fluid δD from −98 to –32‰ (n = 24) and δ13C values of calcite from −6.35 to −9.40‰ (n = 3). Oxygen isotope thermometry for quartz–magnetite pairs yields temperatures from 467 to 526 °C (n = 7, average 503 °C). This probably represents the temperature of gold deposition, because gold is generally associated with magnetite in the ore mineral assemblage. The estimated PT conditions of the gold mineralization range from 467 °C and 1.93 kbar (7 km) to 526 °C and 3.48 kbar (13 km), repectively, and they were obtained from the intersection of isochores with the temperature range derived from the quartz–magnetite isotope geothermometer. This PT range is akin to hypozonal orogenic gold deposits. The association of gold with magnetite and tellurides implies an ore–forming fluid derived from oxidized magmas, similar to those interpreted as ‘orogenic oxidized intrusion-related gold deposits’ in other Precambrian greenstone belts (e.g. Abitibi and Eastern Goldfields).

Granitoid-associated gold mineralization in Egypt: a case study from the Atalla mine

Gold-bearing sulfide-quartz veins cutting mainly through the Atalla monzogranite intrusion in the Eastern Desert of Egypt are controlled by subparallel NE-trending brittle shear zones. These veins are associated with pervasive sericite-altered, silicified, and ferruginated rocks. The hosting shear zones are presumed as high-order structures of the Najd-style faults in the Central Eastern Desert (~ 615–585 Ma). Ore minerals include an early pyrite-arsenopyrite (±pyrrhotite) mineralization, partly replaced by a late pyrite-galena-sphalerite-chalcopyrite (±gold/electrum ± tetrahedrite ± hessite) assemblage. Gold occurs as small inclusions in pyrite and arsenopyrite, or more commonly as intergrowths with galena and sphalerite/tetrahedrite in microfractures. Arsenopyrite geothermometry suggests formation of the early Fe-As-sulfide mineralization at 380–340 °C, while conditions of deposition of the late base metal-gold assemblage are assumed to be below 300 °C. Rare hessite, electrum, and Bi-galena are associated with sphalerite and gold in the late assemblage. The early and late sulfide minerals show consistently a narrow range of δ34S ‰ (3.4–6.5) that overlaps with sulfur isotopic values in ophiolitic rocks. The Au-quartz veins are characterized by abundant CO2 and H2O ± CO2 ± NaCl inclusions, where three-dimensional clusters of inclusions show variable aqueous/carbonic proportions and broad range of total (bimodal) homogenization temperatures. Heterogeneous entrapment of immiscible fluids is interpreted to be caused by unmixing of an originally homogenous, low salinity (~ 2 eq. mass % NaCl) aqueous-carbonic fluid, during transition from lithostatic to hydrostatic conditions. Gold deposition occurred generally under mesothermal conditions, i.e., 1.3 kbar and ~ 280 °C, and continued during system cooling to < 200 °C and pressure decrease to ~ 0.1 kbar. Based on the vein textures, sulfur isotope values, composition of ore fluids, and conditions of ore formation, we suggest that the Atalla monzogranite intrusion acted only as a competent structural host for ore deposition from shear-related, metal-rich fluids migrated up from depth. This model is also presumed for most granitoid-associated Au deposits in the region, considering the similarity in their structural control, alteration pattern and mineralogy, and chemistry of the ore fluids.

Development of stable Pickering emulsions/oil powders and Pickering HIPEs stabilized by gliadin/chitosan complex particles.

In this paper, we demonstrate the use of gliadin/chitosan complex particles (GCCPs) as particulate stabilizers of oil-in-water emulsions of natural oils and water. For this purpose, we fabricated GCCPs through a facile anti-solvent procedure and demonstrated their usage in the formation of Pickering emulsions and Pickering high internal phase emulsions (HIPEs). The GCCPs can be used to produce surfactant-free o/w Pickering emulsions and Pickering HIPEs; unfortunately these emulsions were labile to coalescence. NaCl addition and/or pH regulation, and the combination were used to modify the surface wettability of the complex particles to achieve stable emulsions. The microstructures, e.g., interfacial frameworks, GCCP partition between the continuous phase and interfacial region, and the state of the droplets, of Pickering emulsions were visualized by confocal laser scanning microscopy (CLSM), confirming that the inclusion of NaCl and slightly adjusting pH toward 4.0 and/or 5.0 benefited the adsorption and accumulation of colloid particles at the droplet surface to form an engineered interfacial structure, bridging droplets together through a percolating layer of colloidal particles at the oil/water interface. A schematic representation for the formation route of the emulsions is proposed to relate the physical performance and rheological property with the interfacial structures and aggregate behaviors in the Pickering system stabilized by the complex particles. Interestingly, direct freeze-drying of the emulsions transformed unstable Pickering emulsions into stable oil powders. This study opens a promising route based on Pickering HIPEs or oil powders to structure liquid oils into solid-like fats without artificial trans-fat, which outlines new directions for future fundamental research.

Metallogeny of the Handagai skarn Fe–Cu deposit, northern Great Xing'an Range, NE China: Constraints on fluid inclusions and skarn genesis

The newly discovered Handagai skarn Fe–Cu deposit is located in the northern Great Xing'an Range of NE China and is hosted by the Ordovician Luohe Formation. The orebodies that form the deposit are generally concordant with the bedding within these sediments, and are spatially related to areas of skarn development. The Fe–Cu mineralization in this area records four stages of paragenesis, namely prograde skarn, retrograde skarn, quartz–sulfide, and quartz–carbonate stages. The Handagai deposit is a calcic skarn that is dominated by an andradite–diopside–epidote–actinolite assemblage. The mineralogy and geochemistry of the skarn indicate that it formed from a hydrothermal fluid that altered the carbonate units in this area to a garnet (And42–95Grs4–53) and pyroxene (Di71–78Hd22–29Jo0–2) bearing skarn. The epidote within the skarn has an epidote end-member composition, with the chlorite in the skarn dominantly Fe-rich, indicating that these minerals formed in an Fe-rich environment. The petrographic, microthermometric, and Raman spectroscopic analysis of fluid inclusions within garnet, epidote, actinolite, quartz, and calcite precipitated at different stages of formation of the Handagai deposit indicate that mineralization-related fluid inclusions are either liquid-rich two-phase H2O–NaCl (type I), gas-rich two-phase H2O–NaCl (type II), three-phase (liquid+vapor+solid) H2O–NaCl (type III), or CO2–H2O–NaCl inclusions (type IV). The early stages of mineralization are associated with all four types of inclusion, whereas the later stages of mineralization are only associated with type I and II inclusions. Inclusion homogenization temperatures vary between the four stages of mineralization (370°C–530°C and >600°C, 210°C–290°C, 190°C–270°C, and 150°C–230°C, from early to late, respectively), with salinities also varying between the earlier and later stages of mineralization (11–18 and >45, 7–15, 6–9, and 3–7wt.% NaCl equivalent (equiv.), respectively). The majority of the inclusions within the Handagai deposit have homogenization temperatures and salinities of 200°C–350°C and 4–14wt.% NaCl equiv., respectively, indicating that this is a medium–high temperature and medium–low salinity type deposit. The fluid inclusions were trapped at pressures of 11 to 72MPa, corresponding to depths of 0.4 to 2.9km. The geology, mineralogy, geochemistry, and fluid inclusions microthermometry indicate that the Handagai deposit formed as a result of contact infiltration metasomatism, with the deposition of ore minerals resulting from a combination of factors that include boiling as a result of reduced pressure, cooling, and fluid mixing.

Specificity and Ligand Affinities of the Cocaine Aptamer: Impact of Structural Features and Physiological NaCl.

The cocaine aptamer has been seen as a good candidate for development as a probe for cocaine in many contexts. Here, we demonstrate that the aptamer binds cocaine, norcocaine, and cocaethylene with similar affinities and aminoglycosides with similar or higher affinities in a mutually exclusive manner with cocaine. Analysis of its affinities for a series of cocaine derivatives shows that the aptamer specificity is the consequence of its interaction with all faces of the cocaine molecule. Circular dichroism spectroscopy and 2-aminopurine (2AP) fluorescence studies show no evidence of large structural rearrangement of the cocaine aptamer upon ligand binding, which is contrary to the general view of this aptamer. The aptamer's affinity for cocaine and neomycin-B decreases with the inclusion of physiological NaCl. The substitution of 2AP for A in position 6 (2AP6) of the aptamer sequence eliminated the effect of NaCl on its affinities for cocaine and analogues, but not for neomycin-B, showing a selective effect of 2AP substitution on cocaine binding. The affinity for cocaine also decreased with increasing concentrations of serum or urine, with the 2AP6 substitution blunting the effect of urine. Its low affinities for cocaine and metabolites and its ability to bind irrelevant compounds limit the opportunities for application of this aptamer in its current form as a selective and reliable sensor for cocaine. However, these studies also show that a small structural adjustment to the aptamer (2AP exchanged for adenine) can increase its specificity for cocaine in physiological NaCl relative to an off-target ligand.

Compositions and Pressure–Temperature Conditions of Metamorphic Fluids Overprinting the Talate VMS Pb–Zn Deposit, Southern Altay, China

The Talate Pb–Zn deposit, located in the east of the NW–SE extending Devonian Kelan volcanic‐sedimentary basin of the southern Altaides, occurs in the metamorphic rock series of the upper second lithological section of the lower Devonian lower Kangbutiebao Formation (D1k12). The Pb–Zn orebodies are stratiform and overprinted by late sulfide–quartz veins. Two distinct mineralization periods were identified: a submarine volcanic sedimentary exhalation period and a metamorphic hydrothermal mineralization period. The metamorphic overprinting period can be further divided into two stages: an early stage characterized by bedding‐parallel lentoid quartz veins developed in the chlorite schist and leptite of the ore‐bearing horizon, and a late stage represented by pyrite–chalcopyrite–quartz veins crosscutting chlorite schist and leptite or the massive Pb–Zn ores. Fluid inclusions in the early metamorphic quartz veins are mainly CO2–H2O–NaCl and carbonic (CO2±CH4±N2) inclusions with minor aqueous inclusions. The CO2–H2O–NaCl inclusions have homogenization temperatures of 294–368° C, Tm,CO2 of –62.6 to –60.5°C, Th,CO2 of 7.7 to 29.6°C (homogenized into liquid), and salinities of 5.5–7.4 wt% NaCl eqv. The carbonic inclusions have Tm,CO2 of –60.1 to –58.5°C, and Th, CO2 of –4.2 to 20.6°C. Fluid inclusions in late sulfide quartz veins are also dominated by CO2–H2O–NaCl and CO2±CH4 inclusions. The CO2–H2O–NaCl inclusions have Th,tot of 142 to 360°C, Tm,CO2 of –66.0 to –56.6°C, Th,CO2 of –6.0 to 29.4°C (homogenized into liquid) and salinities of 2.4–16.5 wt% NaCl eqv. The carbonic inclusions have Tm, CO2 of –61.5 to –57.3°C, and Th, CO2 of –27.0 to 28.7°C. The aqueous inclusions (L‐V) have Tm,ice of –9.8 to –1.3°C and Th,tot of 205 to 412°C. The P–T trapping conditions of CO2‐rich fluid inclusions (100–370 MPa, 250–368°C) are comparable with the late‐ to post‐regional metamorphism conditions. The CO2‐rich fluids, possibly derived from regional metamorphism, were involved in the reworking and metal enrichment of the primary ores. Based on these results, the Talate Pb–Zn deposit is classified as a VMS deposit modified by metamorphic fluids. The massive Pb–Zn ores with banded and breccia structures were developed in the early period of submarine volcanic sedimentary exhalation associated with an extensional subduction‐related back‐arc basin, and the quartz veins bearing polymetallic sulfides were formed in the late period of metamorphic hydrothermal superimposition related to the Permian–Triassic continental collision.