Acid In Fluid Research Articles

A Transformative Wearable Corneal Microneedle Patch for Efficient Therapy of Ocular Injury and Infection.

Ocular injury and infection are significant causes of vision impairment and blindness globally. Effective treatment is, however, challenging due to the physical barrier of the cornea, which restricts drug penetration in the eye, as well as the presence of eye injury that necessitates continuous delivery of growth factors on the ocular surface for cornea healing. Here, we introduce a transformative wearable corneal microneedle (MN) patch designed for efficient therapy of ocular injury and infection. The MN patch comprises water-soluble tips that encapsulate antibacterial nanoparticles (NPs), along with a transformative backing layer that contains epidermal growth factor (EGF). Upon insertion into the eye, the MN tips dissolve swiftly within the cornea stroma, resulting in the release of the antimicrobial NPs to efficiently eradicate bacteria. Meanwhile, the residual backing layer undergoes rapid in situ transformation upon contact with mildly acidic fluid from infected corneal edema, converting into a contact lens that conforms to the eye's surface, which facilitates sustained release of EGF on the ocular surface over 8h to promote corneal healing. Benefiting from these features, the designed transformative corneal MN patch demonstrates superior efficacy in treating ocular injuries and infections in vivo, offering a promising therapeutic strategy to manage eye diseases.

Evolutionary insights into gut acidification: Invertebrate-like mechanisms in the basal vertebrate hagfish.

Acidification is a key component of digestion throughout metazoans. The gut digestive fluid of many invertebrates is acidified by the vesicular-type H+-ATPase (VHA). In contrast, vertebrates generate acidic gut fluids using the gastric H+/K+-ATPase (HKA); an evolutionary innovation linked with the appearance of a true stomach that greatly improves digestion, absorption, and immune function. Hagfishes are the most basal extant vertebrates, and their mechanism of digestive acidification remains unclear. Herein we report that the stomachless Pacific hagfish (Eptatretus stoutii) acidify their gut using the VHA, while searches of E. stoutii gut transcriptomes and the genome of a closely related hagfish species (E. burgerii) indicate they lack HKA, consistent with its emergence following the 2R whole genome duplication. Immunostaining revealed prominent VHA presence in the apical membrane of enterocytes and sub-apical expression of both VHA and sAC. Interestingly, akin to vertebrates, VHA was also observed in immature pancreatic-like zymogen granules and was noticeably absent from the mature granules. Furthermore, isolated gut sacs from fed hagfish demonstrate increased VHA-dependent luminal H+ secretion that is stimulated by the cAMP pathway. Overall, these results suggest that the hagfish gut shares the trait of VHA-dependent acidification with invertebrates, while simultaneously performing some roles of the pancreas and intestine of gnathostomes.

Location of NWA 6148 and NWA 10153 in the nakhlite body and their aqueous alteration

AbstractThe petrologic and mineralogical characteristics and alteration processes of the nakhlites NWA 6148 and NWA 10153 were studied. Both consist of augite, olivine, and mesostasis. Based on the characteristics of each volume fraction of the components and the chemical composition of olivine and pyroxene, NWA 6148 correspond to lava units crystallized at 1346–1391 Ma in the nakhlite body. The position of NWA 10153 in the nakhlite body is unclear. Iron oxides/hydroxides, barite, and calcite fill the fractures of NWA 6148, which are terrestrial weathering products. In NWA 10153, olivine grains are replaced by goethite, magnetite, saponite, amorphous silica, jarosite, and siderite. Although it is uncertain whether all of the alteration minerals were formed on the surface of Mars or on the surface of Earth, NWA 10153 records two different alteration environments: reducing, neutral to alkaline, and oxidizing and acidic. As in NWA 6148 and NWA 10153, the assemblage of alteration mineral species in other nakhlites is also heterogeneous even within the same lava unit. The nakhlite body was altered by the oxidizing acidic fluid after a ‐bearing reducing neutral to alkaline fluid. The drastic change of alteration environments may have been caused by an impact event.

Supercritical CO2-Stable Cementing Materials Based on Vinyl Ester Resin for Maintaining Wellbore Integrity.

Ensuring long-term wellbore integrity is critical for carbon dioxide geological storage. Ordinary Portland cement (PC) is usually used for wellbore primary cementing and plug operation, and set cement is easily corroded by acidic fluids, such as carbon dioxide, in underground high-temperature and high-pressure (HTHP) environments, resulting in a decrease in the mechanical properties and an increase in permeability. In order to achieve long-term wellbore integrity in a CO2-rich environment This study introduces materials such as thermosetting vinyl ester resin (TSR), filler composite resin (FCR), and low-cost resin cement (RC). Corrosion experiments were conducted using four materials in 28 days under supercritical carbon dioxide gas and water phase conditions of 60 °C and 10 MPa. The samples were characterized through mechanical property testing machines, core permeability measuring instruments, FTIR, XRD, and SEM. The results proved that after corrosion, PC mechanical properties decreased, the permeability increased, and the microscopic composition and morphology changed greatly. Penetrating corrosion occurs in the sample in the gas phase environment, and propulsive corrosion from outside to inside occurs in the water phase environment. However, TSR, FCR, and RC materials all maintain excellent resistance to carbon dioxide corrosion in gas and water environments. They have higher compressive strength and extremely low permeability compared to ordinary Portland cement. These three materials' compressive strengths can be maintained around 131, 99, and 58 MPa, and permeability can be stabilized at <6 × 10-7, <6 × 10-7, and 0.16 mD levels. In summary, the above three materials all show better performance than ordinary Portland cement and are promising alternative materials that can be used in primary cementing and plug operations of carbon dioxide geological storage wells.

Dynamic fracture toughness and fractal characteristics of crack in pressurized acidified Qinshui coal under impact loading

To investigate the effect of acid fracturing fluid on the fracture toughness and fractal properties of crack propagation in Qinshui coal under impact load, the 50 mm diameter split Hopkinson pressure bar device was employed to carry out mode I dynamic fracture toughness tests on Qinshui anthracite samples treated with acid fracturing fluid and water-based fracturing fluid under different impact pressures. Coal samples were subjected to force saturation and acidity treatment using an innovative apparatus. The fracture propagation phase of the specimen was acquired by a high-speed camera sensor. Combined with Image J analysis software and PCAS image recognition system, the macroscopic crack propagation trajectory and probability entropy of micro pores in coal samples were quantitatively analyzed. These findings revealed that dynamic fracture toughness endowed a strong rate-response relationship. When the impact pressure is 0.3, 0.4, and 0.5 MPa, the average fracture toughness of the water-based fracturing fluid group coal specimens was respectively 0.64, 1.20, and 1.31 times better that of the acidic fracturing fluid group. The rate of crack propagation and the dynamic fracture toughness of coal were reduced after acidification of the specimens. The crack growth rate initially surged, then decreased rapidly until it reached a stable state under impact load, while the variation in crack growth length and opening breadth showed a time-dependent increase. Crack propagation resistance and dynamic fracture toughness of coal are reduced by the acidification of the specimens. The fractal dimension of cracks in specimen increased under the impact of pressure growth. The fractal dimensions of crack in coal samples under the action of acidic fracturing fluid at 0.30, 0.40, and 0.50 MPa are 1.066, 1.078, and 1.087 times that of water-based fracturing fluid, as well as 1.119, 1.136, and 1.157 times that of natural state coal samples. With the increase in impact pressure, the entropy magnitude of the pore probability on the fracture surface of the coal sample also increased. The fracture surface morphology of coal sample transformed from compact and neat to loose and porous with the action of acidification. The dual mechanism of weakening and enhancing the fracture behavior of anthracite coal by fracturing fluid under different loading rates was explored, and a microscopic fracture mechanics model incorporating loading rate was developed based on the dual nature of the fracturing fluid and linear elastic fracture mechanics theory. The study results offer empirical evidence to investigate the process of fracture initiation and propagation in acid fracturing in Qinshui coal, and provide theoretical direction for designing acid fracturing in coal seams and controlling complicated fracture network.

Pharmacological investigation of selected 1,2,4 triazole derivative against ethanol induced gastric ulcer.

The present study aims to assess the therapeutic potential of (2S,3S,4S,5S,6S-2-(acetoxymethyl)-6-(4-chlorophenyl)-3-(pyridine-4-yl)5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl tetrahydro-2H-pyran 3,4,5tryltriacetate (JAK05) on gastric ulcer. The current study was designed to evaluate the anti-ulcer potential of JAK05 against ethanol-induced gastric ulcer by employing in silico, in vitro and in vivo techniques. In silico studies, JAK05 has a binding score ranging from -8.51 to -21.38 (kcal/mol). Molecular dynamics simulation at 100ns shows better structural stability, stable binding affinity and stable conformation when bonded to H+/K+-ATPase. In vitro study demonstrates that JAK05 inhibits Helicobactor pylori. In vivo study confirmed that JAK05 promotes ulcer healing in rats at a dose of 40mg/kg and demonstrated a protective effect on the gastric mucosa, comparable to omeprazole by modulating acid secretion and fluid volume. Glutathione, glutathione-s-transferase and catalase levels increased in rat stomach tissue while nitric oxide decreased with the administration of JAK05. Additionally, lipid peroxide levels were found to have significantly decreased. Pathological histopathology analysis shows improved tissue structure and reduced inflammatory markers. These findings were confirmed using immunohistochemistry and enzyme-linked immunosorbent assay. JAK05 exhibits a high affinity for selected targets. JAK05 shows anti-ulcer properties by targeting through multiple mechanisms inhibiting H. pylori, reducing oxidative stress, suppressing inflammation and blocking acid production.

Coupled antimony and sulfur isotopic composition of stibnite as a window to the origin of Sb mineralization in epithermal systems (examples from the Kremnica and Zlatá Baňa deposits, Slovakia)

AbstractStibnite is a relatively common mineral in epithermal deposits, with little known about Sb transport and efficient stibnite precipitation. The famous Kremnica Au-Ag low-sulfidation deposit and Zlatá Baňa intermediate-sulfidation Pb-Zn-Cu-Au-Ag-Sb deposit are hosted in two different Neogene volcanic fields in Western Carpathians, Slovakia. In both deposits, stibnite-rich veins occur outside of major vein structures, accompanied by illite, illite/smectite, and kaolinite alteration, and affiliated to late-stage fluids (&lt; 2 wt% NaCl eq., &lt; 150 °C). Sulfur isotopic composition of stibnite and sulfides is different at both deposits, likely due to a different magmatic-hydrothermal evolution of the parental magmatic chambers in the Central and Eastern Slovak Volcanic Fields. The Sb isotopes (δ123Sb), however, show similar values and trends of gradual simultaneous increase with δ34S values, explained by a progressive precipitation of stibnite and its fractionation with the fluid. The data were modeled by two coupled Rayleigh fractionation models, (for Sb and for S), assuming a predominant Sb transport in HSb2S4– with a variable amount of S species. Higher molality ratio mS/mSb of fluids was found in Kremnica (~ 3–4) than in Zlatá Baňa (~ 2). At both deposits, the heaviest δ123Sb values are accompanied by a decrease in the δ34S values probably due to the commencement of pyrite/marcasite precipitation. According to thermodynamic models of solubility of Sb(III) complexes and observations from active geothermal fields, stibnite precipitation was triggered by temperature decrease accompanied by mixing with a mildly acidic fluid (pH 4–5) of a steam-heated CO2-rich condensate on margins and in the final stages of epithermal systems. The proposed model for the origin of stibnite-bearing veins in epithermal systems can be used for their better targeting and efficient mineral exploration.

The Impact of Acid Strength and Mineral Composition on Spontaneous Imbibition with Reactive Fluids

Capillary rise experiments are conducted in a set of calcareous and siliceous rocks with varying mineralogy and petrophysical properties to understand the coupled impact of reactivity and spontaneous imbibition. A capillary rise experiment is performed in each sample: first with deionized water, then with a dilute acidic solution, and finally again with deionized water, and the capillary rise profile for each is recorded. Pre- and post-acid petrophysical properties such as porosity, permeability, pore size distribution, and contact angle are measured for each sample. The mineral makeup of the rocks significantly influences how the acidic fluids penetrate the samples. The primary reactions are the dissolution of Ca- and Mg-rich minerals which alter the pore network. The higher acid strength results in higher capillary rise in calcareous rocks and results in an increase in the average pore size. The same pH acid results in lower capillary rise in the siliceous rocks, and a general decrease in the average pore size is observed. Changes in contact angle indicate increased water affinity in carbonate and reduced affinity in sandstone. The link between capillary interactions and fluid reactivity is often overlooked in fluid flow studies, and this research sheds light on the importance of reactivity during spontaneous imbibition, offering insights into dissolution and precipitation processes during capillary flow.

A phase-field modeling study for reaction instability and localized fluid flow in carbonate rocks

As acidic fluids flow and dissolve minerals in carbonate formations, the reaction may localize into a dendritic pattern under certain conditions known as wormhole. Wormhole is considered to be triggered by pore-scale heterogeneity in the rock that promotes preferential flow paths. Therefore, in macroscale (Darcy scale) simulation, numerical models usually need to prescribe a certain degree of macroscopic heterogeneous permeability to promote localized dissolution (wormhole). However, experimental studies have shown that wormholes form in synthetic plasters without apparent heterogeneity, implying that macroscopic heterogeneity is not a necessary prerequisite for wormhole formation and prescribed heterogeneity may impose unnecessary biases. Here, we applied a macroscale wormhole model based on a phase-field approach to demonstrate that wormhole can form in macroscopically homogeneous media as long as the inlet velocity meets the infiltration-reaction instability condition obtained from perturbation analysis. Furthermore, we simulated wormhole growth behaviors in homogeneous and heterogeneous permeability fields with the standard variance values of 0.5, 1.0 and 2.0. The simulation results showed that the normalized injectivity decreases from 3.90 to 3.15 when the standard variance changed from 0.5 to 2.0 indicating that heterogeneity may actually suppress the wormhole growth because an increasing amount of acid infiltrates into the branched wormholes. These findings suggest that permeability heterogeneities should not be treated as a trigger for wormholes in the macroscale numerical simulation. Instead, they should be regarded as parameters that influence the nucleation and growth of wormholes because the permeability field has significant effects on post-acid wormhole geometry and resultant well productivity and injectivity.

A retarded foam acid fluid system for low-temperature dolomite geothermal reservoir stimulation and its action mechanisms

Acidizing improves geothermal reservoir productivity by dissolving rocks to increase formation permeability, which is achieved by injecting acid fluids into reservoir formations. However, conventional acid fluids either can not achieve effective acidizing or cause geothermal reservoir damages. Foam acid fluids, which have been applied for oil-gas reservoir stimulation, can realize effective acidizing by retarding acid-rock reactions, and can protect reservoirs. Here, a foam acid fluid system is proposed, aiming at achieving efficient acidizing and reservoir protection in low-temperature dolomite geothermal reservoirs. Formic acid (FA) and acetic acid (HAc) are used to replace a portion of hydrochloride (HCl) acid. Alkyl glycine surfactant AGS-12 is added for foaming, while xanthan gum and nano silica particles are used to stabilize foams. Corrosion inhibitor and ferric ion stabilizer are added to inhibit acid corrosion of steel and ferric ion precipitations. The acidizing effect was evaluated through foam stability, dissolution performance, corrosion inhibition performance, and compatibility. Microscopic observation, field emission scanning electron microscope, and numerical simulation were applied to reveal the mechanisms of temporal evolution of foams and acid dissolution behaviors. Results show that the foam acid fluid with 5 wt% FA, 5 wt% HAc and 10 wt% HCl acid has the best foam stability and retardation effect. Compared to non-foam acid fluid, the decrease degree of the cuttings mass change rate in foam acid fluids exceeds 50 %, and foaming primarily retards acid-rock reactions. Simulation results is consistent with the experiment results, demonstrating that the cuttings dissolve less in FA and HAc. Calcium (Ca) content on the cuttings surfaces after acid-rock reactions in foam acid fluids with FA and HAc is less than that after acid-rock reactions in foam acid fluid with sole HCl acid, indicating that FA and HAc inhibit Ca-bearing mineral precipitations, as formate and acetate ions can chelate with Ca2+. The replacement of HCl acid by FA and HAc contributes to a low corrosivity and good compatibility of the foam acid fluids due to a reduced hydrogen ions resulted from partial dissociation of weak acids. This study shows the feasibility of foam acid fluids during geothermal reservoir stimulation with eliminated reservoir damages.

Influence of the substitution of CaO by SrO on the structure, degradation and in vitro apatite formation of sol–gel derived SiO2–CaO–SrO–P2O5system bioactive glasses

The present study investigates the influence of the substitution of CaO by SrO on the structure, degradation and in vitro apatite formation of sol–gel-derived bioactive glasses with composition of 58SiO2–(38-x)CaO–xSrO–4P2O5, where x varies between 0 and 10 mol.%. The IV-type nitrogen adsorption/desorption isotherms and pore size values (ranging from 5.41 to 12.56 nm) confirmed the mesoporous structure of the synthesized glasses. The detailed structural analysis was carried out by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). As network modifiers, the addition of Ca and Sr oxides disrupted the bonds of bridging oxygens (BOs) and resulted in the formation of non-bridging oxygens (NBOs), where the substitution of Ca with Sr led to an increase in Q1 units and a decrease in Q3 units. The effects of the addition of Sr on sample degradation and apatite formation were assessed using an assay in tris-(hydroxymethyl)-aminomethane and hydrochloric acid (Tris–HCl) and simulated body fluid (SBF). The results demonstrated that the substitution of CaO by SrO in the CaO–SiO2–P2O5 bioglass system altered the glass structure, resulting in reduced sample degradation and delayed apatite formation. This suggests that the incorporation of Sr into bioactive glasses may serve as a promising strategy to regulate the structure, dissolution behavior and apatite formation of silicate-based glasses, particularly concerning their long-term applications within the human body.

PH-responsive magnetic nanocarrier based on hyaluronic acid-folic acid conjugated Fe3O4 nanoparticles for controlled delivery of imatinib: Isotherms, kinetics, and thermodynamics studies

A novel pH-responsive magnetic nanocarrier was synthesized with hyaluronic acid/folic acid conjugated magnetic nanoparticles and used as a drug carrier for imatinib drug delivery. Magnetic nanoparticles were surface modified with (3-glycidyloxypropyl) trimethoxysilane. Grafting of hyaluronic acid/folic acid on these magnetic nanoparticles was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, thermogravimetric analysis, and vibrating sample magnetometer. The effect of adsorption parameters such as pH, initial concentration, contact time, and adsorbent dosage was examined. The pseudo-second-order model best described the kinetic data, while the Langmuir model best described the isotherm data, indicating physico-sorption and monolayer imatinib adsorption, respectively. Also, thermodynamic experiments showed that the uptake of the drug by the magnetic adsorbent was endothermic and spontaneous. The maximum sorption capacity of unmodified magnetic nanoparticle for imatinib was 6.38 mg/g and for modified magnetic nanoparticles, it was 16.56 mg/g. Imatinib as an anticancer drug, was loaded and the release curve was investigated at pH 5.6 and 7.4 for 6 h. At acidic fluid, the amount of imatinib released increased to 63.01 % compared to physiological fluid with 26.04 % drug release.

Characteristics and main controlling factors of the Sangonghe tight sandstone reservoirs in the Shengbei Sub-sag of the Turpan-Hami basin, China

The Sangonghe tight sandstone hydrocarbon reservoirs in the Shengbei Sub-sag of the Turpan-Hami Basin are key areas for hydrocarbon exploration. However, previous research has mostly focused on petrological characteristics, physical properties, and pore types. There is a lack of understanding regarding diagenesis, microscopic pore-throat features, and the impact of overpressure on the reservoir. This gap in knowledge poses a disadvantage for future studies and hydrocarbon exploration. This study examines the Sangonghe tight sandstone hydrocarbon reservoirs in the Shengbei Sub-sag of the Turpan-Hami Basin. It combines cast thin sections, physical property tests, high-pressure mercury injection experiments, low-temperature nitrogen adsorption experiments, and well logging overpressure identification to investigate the basic characteristics, diagenesis, and microscopic pore-throat features of these reservoirs. Based on this analysis, the study identifies the main controlling factors of the reservoir properties and presents three key findings. First, the reservoir rocks are primarily composed of lithic sandstone and feldspathic lithic sandstone with porosity ranging from 4% to 10% and permeability ranging between 0.1 and 10 mD, classifying it as a low-porosity, low-permeability tight sandstone reservoir. Second, the reservoir has undergone several diagenetic processes, with significant compaction and common occurrences of cementation and metasomatism. Acidic dissolution is the main dissolution process, but it is relatively weak. The pore-throat system exhibits poor and concentrated sorting, with nanometer-sized pores being predominant. These include 'ink-bottle' pores with narrow necks and wide bodies, and parallel plate-structured fissure pores. Finally, the development of the reservoirs is mainly influenced by sedimentation, dissolution, and overpressure. The parent rock provenance features a high content of stable heavy minerals, larger grain sizes, and thicker sand body layers. These factors enhanced the reservoir's resistance to compaction and promoted the development of primary intergranular pores. Additionally, organic acid fluids caused extensive dissolution of feldspar and lithic fragments, resulting in the formation of numerous secondary dissolution pores. Additionally, under-compaction overpressure helped preserve primary pores, while hydrocarbon generation overpressure extended the hydrocarbon generation period. This extended period provided the driving force for fluid migration, enhanced the transformation of reservoir space, and aided in hydrocarbon accumulation.

Predestinative role acidic cerebrospinal fluid on the destiny of central channel in spinal cord following subarachnoid hemorrhage: an experimental study

Predestinative role acidic cerebrospinal fluid on the destiny of central channel in spinal cord following subarachnoid hemorrhage: an experimental study

Optimization of pH-responsive microgel for the co-delivery of Weizmannia coagulans and procyanidins to enhance survival rate and tolerance

The purpose of this study was to prepare a pH-responsive microgel for co-delivering Weizmannia coagulans 99 (BC99) and procyanidins (PCs) to enhance the survival rate and tolerance of probiotics in complex micro-environment. The effects of different concentrations of PCs on the properties of microgels were optimized, and found that the spherical microgels had higher encapsulation efficiency (90.27 ± 2.51%) and smaller size when the concentration of PCs was 20 μg/mL. The interaction among PCs, pectin and protein could effectively improve the survival rate of BC99 under different pH, bile salt, digestive enzyme and temperature conditions, maintain their stability in acidic gastric fluid, and realize the release of probiotics in neutral intestinal fluid. Moreover, the microgel was able to protect BC99 against H2O2 and antibiotics. This work provides a pH-responsive co-loaded microgels for BC99 and PCs, and has the potential in the loading and delivery of other probiotics and polyphenols.

Biomimetic composite gelatin methacryloyl hydrogels for improving survival and osteogenesis of human adipose-derived stem cells in 3D microenvironment

Gelatin methacryloyl (GelMA) hydrogels are used for stem cell encapsulation in bone tissue engineering due to their fast and stable photo-crosslinking. However, cell viability and ability to induce osteogenesis are reduced by reactive oxygen species (ROS) produced during the crosslinking reaction. In this study, we developed biomimetic nanoparticles (TMNs) by combining tannic acid (TA) and simulated body fluid (SBF) minerals, and used them to synthesize GelMA-based composite hydrogels for addressing those limitations. The optimal concentrations of TA and SBF were investigated to create nanoparticles that can effectively scavenge ROS and induce osteogenesis. The incorporation of TMNs into composite hydrogels (G-TMN) significantly enhanced the survival and proliferation of encapsulated human adipose-derived stem cells (hADSCs) by providing resistance to oxidative conditions. In addition, the ions that were released, such as Ca2+ and PO43−, stimulated stem cell differentiation into bone cells. The hADSCs encapsulated in G-TMN had 2.0 ± 0.8-fold greater viability and 1.3 ± 1.8 times greater calcium deposition than those encapsulated in the hydrogel without nanoparticles. Furthermore, the in vivo transplantation of G-TMN into a subcutaneous mouse model demonstrated the rapid degradation of the gel-network while retaining the osteoinductive particles and cells in the transplanted area. The increased cellular activity observed in our multifunctional composite hydrogel can serve as a foundation for novel and effective therapies for bone deformities.

Magnetite Survivability and Non‐Stoichiometric Magnetite Formation in Presence of Oxyhalogen Brines on Mars

AbstractThe mixed Fe(II)/Fe(III) mineral magnetite [Fe3O4] of various stoichiometric and non‐stoichiometric compositions have been reported in Martian soils and rocks by several rover missions. Magnetite is an important paleomagnetic indicator mineral and can serve as a ‘biogeobattery’ as a consequence of its magnetic properties and the mixed valence state of iron in its structure. Here, we assess the extent of oxidative weathering of magnetite in presence of chlorate and bromate containing solutions that are likely important oxidants on Mars. Oxyhalogen species, chlorate and bromate, produced non‐stoichiometric magnetite [Fe(II)/Fe(III) &lt; 0.5] in Mars‐relevant, near‐neutral pH fluids; no other ferric minerals were produced. The same results were observed in highly acidic fluids with or without oxyhalogens. Owing to its resistance to extensive oxidation, magnetite can serve as an important archive of geochemical, paleomagnetic, and astrobiological information in samples that will be returned by the Mars Sample Return mission.

Lithofacies and diagenetic controls on thrombolitic dolomite reservoir development from the Precambrian Dengying Formation in the central Sichuan Basin, SW China

Microbialite reservoirs are of great importance in oil and gas exploration. However, there is still a lack of comprehensive studies on the formation mechanisms of thrombolitic reservoirs, a specific type of microbialite. This research focuses on the oldest thrombolitic dolomite reservoir located within the Precambrian Dengying Formation in the central Sichuan Basin, southwestern China. A multi-disciplinary approach was employed to characterize different thrombolite facies and elucidate the formation mechanism of thrombolitic dolomite reservoirs and their controlling factors, involving core observation, thin-section analysis, cathodoluminescence, scanning electron microscope (SEM) microscopy, elemental analysis using LA-ICP-MS, and carbon and oxygen stable isotope analysis. Based on variations in texture, four types of thrombolite were identified: 1) distinct clotted thrombolite, 2) diffuse and regular clotted thrombolite, 3) diffuse and irregular clotted thrombolite, and 4) composite clotted thrombolite. Notably, the diffuse clotted thrombolitic dolomite is the prevalent lithology in the reservoir. Through modification by meteoric water, organic acid fluids, and hydrothermal fluids, a reservoir with dominant porosity in the form of primary growth-framework pores, dissolution pores, and vugs was formed. This resulted in the development of two high-quality reservoir intervals within the Second Member and at the top of the Fourth Member of the Dengying Formation. The growth-framework porosity of the thrombolites, epigenetic karstification, and tectonic fracturing were mainly conducive to reservoir development. However, various types of cementation have reduced porosity and connectivity within the reservoir. Overall, this study is a valuable example of the methodology required to understand meso- and microstructures of deep-buried thrombolitic dolomite reservoirs, including their heterogeneities and diagenesis, as the original structures influence diagenesis.

A Polysaccharide-Based Oral-Vaccine Delivery System and Adjuvant for the Influenza Virus Vaccine.

Influenza virus enters the host body through the mucosal surface of the respiratory tract. An efficient immune response at the mucosal site can interfere with virus entry and prevent infection. However, formulating oral vaccines and eliciting an effective mucosal immune response including at respiratory mucosa presents numerous challenges including the potential degradation of antigens by acidic gastric fluids and the risk of antigen dilution and dispersion over a large surface area of the gut, resulting in minimal antigen uptake by the immune cells. Additionally, oral mucosal vaccines have to overcome immune tolerance in the gut. To address the above challenges, in the current study, we evaluated inulin acetate (InAc) nanoparticles (NPs) as a vaccine adjuvant and antigen delivery system for oral influenza vaccines. InAc was developed as the first polysaccharide polymer-based TLR4 agonist; when tailored as a nanoparticulate vaccine delivery system, it enhanced antigen delivery to dendritic cells and induced a strong cellular and humoral immune response. This study compared the efficacy of InAc-NPs as a delivery system for oral vaccines with Poly (lactic-co-glycolic acid) (PLGA) NPs, utilizing influenza A nucleoprotein (Inf-A) as an antigen. InAc-NPs effectively protected the encapsulated antigen in both simulated gastric (pH 1.1) and intestinal fluids (pH 6.8). Moreover, InAc-NPs facilitated enhanced antigen delivery to macrophages, compared to PLGA-NPs. Oral vaccination studies in Balb/c mice revealed that InAc-Inf-A NPs significantly boosted the levels of Influenza virus-specific IgG and IgA in serum, as well as total and virus-specific IgA in the intestines and lungs. Furthermore, mice vaccinated with InAc-Inf-A-NPs exhibited notably higher hemagglutination inhibition (HI) titers at mucosal sites compared to those receiving the antigen alone. Overall, our study underscores the efficacy of InAc-NPs in safeguarding vaccine antigens post-oral administration, enhancing antigen delivery to antigen-presenting cells, and eliciting higher virus-neutralizing antibodies at mucosal sites following vaccination.

Anatomy of a fumarole field: drone remote-sensing and petrological approaches reveal the degassing and alteration structure at La Fossa cone, Vulcano, Italy

Abstract. Hydrothermal alteration and mineralization processes can affect the physical and chemical properties of volcanic rocks. Aggressive acidic degassing and fluid flow often also lead to changes in the appearance of a rock, such as changes in surface coloration or intense bleaching. Although hydrothermal alteration can have far-reaching consequences for rock stability and permeability, limited knowledge exists on the detailed structures, extent, and dynamic changes that take place near the surface of hydrothermal venting systems. By integrating drone-based photogrammetry with mineralogical and chemical analyses of rock samples and surface gas flux, we investigate the structure of the evolving volcanic degassing and alteration system at the La Fossa cone on the island of Vulcano, Italy. Our image analysis combines principal component analysis (PCA) with image classification and thermal analysis through which we identify an area of approximately 70 000 m2 that outlines the maximum extent of hydrothermal alteration effects at the surface, represented by a shift in rock color from reddish to gray. Within this area, we identify distinct gradients of surface coloration and temperature that indicate a local variability in the degassing and alteration intensity and define several structural units within the fumarole field. At least seven such larger units of increased activity could be constrained. Through mineralogical and geochemical analysis of samples from the different alteration units, we define a relationship between surface appearance in drone imagery and the mineralogical and chemical composition. Gradients in surface color from reddish to gray correlate with a reduction in Fe2O3 from up to 3.2 % in the unaltered regime to 0.3 % in the altered regime, and the latter coincides with the area of increased diffuse acid gas flux. As the pixel brightness increases towards higher alteration gradients, we note a loss of the initial (igneous) mineral fraction and a change in the bulk chemical composition with a concomitant increase in sulfur content from close to 0 % in the unaltered samples to up to 60 % in samples from the altered domains. Using this approach of combined remote-sensing and in situ analyses, we define and spatially constrain several alteration units and compare them to the present-day thermally active surface and degassing pattern over the main crater area. The combined results permit us to present a detailed anatomy of the La Fossa fumarole field, including high-temperature fumaroles and seven larger units of increased alteration intensity, surface temperature, and variably intense surface degassing. Importantly, we also identify apparently sealed surface domains that prevent degassing, likely as a consequence of mineral precipitation from degassing and alteration processes. By assessing the thermal energy release of the identified spatial units quantitatively, we show that thermal radiation of high-temperature fumaroles accounts for &lt; 50 % of the total thermal energy release only and that the larger part is emitted by diffuse degassing units. The integrated use of methods presented here has proven to be a useful combination for a detailed characterization of alteration and activity patterns of volcanic degassing sites and has the potential for application in alteration research and for the monitoring of volcanic degassing systems.