Acidic Products Research Articles

Magnesium Hydroxide as a Versatile Nanofiller for 3D-Printed PLA Bone Scaffolds.

Polylactic acid (PLA) has attracted much attention in bone tissue engineering due to its good biocompatibility and processability, but it still faces problems such as a slow degradation rate, acidic degradation product, weak biomineralization ability, and poor cell response, which limits its wider application in developing bone scaffolds. In this study, Mg(OH)2 nanoparticles were employed as a versatile nanofiller for developing PLA/Mg(OH)2 composite bone scaffolds using fused deposition modeling (FDM) 3D printing technology, and its mechanical, degradation, and biological properties were evaluated. The mechanical tests revealed that a 5 wt% addition of Mg(OH)2 improved the tensile and compressive strengths of the PLA scaffold by 20.50% and 63.97%, respectively. The soaking experiment in phosphate buffered solution (PBS) revealed that the alkaline degradation products of Mg(OH)2 neutralized the acidic degradation products of PLA, thus accelerating the degradation of PLA. The weight loss rate of the PLA/20Mg(OH)2 scaffold (15.40%) was significantly higher than that of PLA (0.15%) on day 28. Meanwhile, the composite scaffolds showed long-term Mg2+ release for more than 28 days. The simulated body fluid (SBF) immersion experiment indicated that Mg(OH)2 promoted the deposition of apatite and improved the biomineralization of PLA scaffolds. The cell culture of bone marrow mesenchymal stem cells (BMSCs) indicated that adding 5 wt% Mg(OH)2 effectively improved cell responses, including adhesion, proliferation, and osteogenic differentiation, due to the release of Mg2+. This study suggests that Mg(OH)2 can simultaneously address various issues related to polymer scaffolds, including degradation, mechanical properties, and cell interaction, having promising applications in tissue engineering.

Recyclable 2-Fluoropyridine Derivative as a Storage for Highly Electrophilic 1,1-Bis(triflyl)ethylene.

As an easy-to-handle reagent for the in situ generation of outstandingly electrophilic Tf2C=CH2 (Tf=CF3SO2), we have designed and synthesised a novel 4-substituted 2-fluoropyridinium zwitterion, in which a partially fluorinated alkyl group is attached to the pyridinium 4-position. Its zwitterionic nature has been well characterised by quantum chemical bonding analysis. By using this reagent, a wide variety of organic compounds, including commercial bioactive agents, were successfully decorated by the strongly acidic or ionic functionality. Remarkably, the 4-substituted 2-fluoropyridine derivative, which results from the zwitterion with the generation of Tf2C=CH2, can be rapidly separated and recovered from the reaction mixture appropriately using distillation, organic solvent extraction, or fluorous solid phase extraction techniques. Such multi-optionality for the purification methods favours in the isolation of the strongly acidic and/or ionic products.

Histochemical and morphological evaluation of a glyoxal acid-free fixative

ABSTRACT The application of most chemical fixatives, such as formalin, in the anatomic pathology laboratory requires safety training and hazardous chemical monitoring due to the toxicity and health risks associated with their use. Consequently, the use of formalin has been banned in most applications in Europe; the primary exception is its use in the histology laboratory in lieu of a suitable and safer alternative. Glyoxal based solutions, several of which are available commercially, are the most promising alternative fixatives, because they are based on a mechanism of fixation similar to that of formalin. Unlike formalin, however, glyoxal based solutions do not dissociate from water and therefore do not require ventilation measures such as a fume hood. A primary barrier to the adoption of commercially available glyoxal based solutions is their low pH, which can produce undesirable morphological and antigenic tissue alterations; however, a recently available neutral pH glyoxal product (glyoxal acid free) (GAF) has been developed to mitigate the challenges of low pH. We compared the morphology and histochemistry among tissues fixed in 10% neutral buffered formalin, a commercially available acidic glyoxal product (Prefer), and GAF. Tissues fixed in formalin and Prefer exhibited similar morphology and staining properties; tissues fixed with 2% GAF exhibited deleterious effects.

Treatment of cows with rumen atony

Under certain conditions, the main source of energy in the diet of cattle can be concentrated feed, such as cake, meal and legumes. When there is an excess of them in the rumen, acidic metabolic products that block the reproduction of normal microflora are formed during the digestion process. Therefore, acidic silage and excess of concentrates in the diet contributes to the development of rumen acidosis. Rumen acidosis leads to a number of diseases, such as atony of the proventriculus, osteodystrophy, ketosis, hepatosis. All these pathologies are accompanied by a decrease in milk production. The purpose of this work was a comparative analysis of various treatment regimens for cow rumen acidosis. We conducted two series of experiments on cows with rumen acidosis. In the first series, we studied the effectiveness of oral administration of sodium acetate in doses of 0.4 g/kg, 0.5 g/kg and 0.6 g/kg body weight for rumen acidosis. In the second experiment, we studied the effectiveness of oral administration of calcium acetate in doses of 0.2 g/kg, 0.3 g/kg and 0.4 g/kg body weight. In the first experiment, it was found that the effectiveness of sodium acetate for rumen acidosis was almost identical for concentrations of 0.5 and 0.6 g/kg., a single use of sodium acetate led to recovery in 83.3% of cases. The average duration of restoration of rumen motility was 410 minutes. It was revealed that, in comparison with sodium acetate, calcium acetate is significantly more effective after 1-2 applications of calcium acetate at a dose of 0.3 g/kg. With oral administration of sodium acetate and calcium acetate in cows with acute rumen atony, it is possible to normalize the motor function of the rumen, rumen digestion in general, alkaline reserve, and glucose levels. The duration of the period to restore the rumen motility when using sodium acetate is six to eight hours, when using calcium acetate - two to three hours.

Improving the Quality and Safety of Barley by Controlled Homolactic Fermentation with Lactic Acid Bacteria

Fermentation by lactic acid bacteria can improve the nutritional and hygienic quality of barley, as well as its organoleptic properties. The aim of this study was to select a suitable lactic ferment to add value to barley through a controlled homolactic fermentation process, which can be used to produce a natural base product for broiler feed. Four different combinations of lactic strains were tested for their acidifying power, antibacterial activity, and fermentation performanceThe mixed culture of homolactic ferment FS4, composed of Lactobacillus plantarum (SC1), Pediococcus spp (SC4), and Lactococcus lactis ssp (SC5), showed the best result in terms of pH reduction, acidity production, and inhibition of spoilage bacteria. The in vivo application of the ferment FS4 on barley resulted in a decrease in pH to 4.12 after 15 days of fermentation, and an improvement in its hygienic quality, with the possibility of also enhancing its nutritional quality. This study demonstrated that FS4 is a suitable lactic ferment for valorizing barley through a controlled homolactic fermentation process, which can be used to produce a natural base product for animal feed with improved quality and safety.

Breaking Osteoclast-Acid Vicious Cycle to Rescue Osteoporosis via an Acid Responsive Organic Framework-Based Neutralizing and Gene Editing Platform.

In the osteoporotic microenvironment, the acidic microenvironment generated by excessive osteoclasts not only causes irreversible bone mineral dissolution, but also promotes reactive oxygen species (ROS) production to induce osteoblast senescence and excessive receptor activator of nuclear factor kappa-B ligand (RANKL) production, which help to generate more osteoclasts. Hence, targeting the acidic microenvironment and RANKL production may break this vicious cycle to rescue osteoporosis. To achieve this, an acid-responsive and neutralizing system with high in vivo gene editing capacity is developed by loading sodium bicarbonate (NaHCO3) and RANKL-CRISPR/Cas9(RC) plasmid in a metal-organic framework. This results showed ZIF8-NaHCO3@Cas9 (ZNC) effective neutralized acidic microenvironment and inhibited ROS production . Surprisingly, nanoparticles loaded with NaHCO3 and plasmids show higher transfection efficiency in the acidic environments as compared to the ones loaded with plasmid only. Finally, micro-CT proves complete reversal of bone volume in ovariectomized mice after ZNC injection into the bone remodeling site. Overall, the newly developed nanoparticles show strong effect in neutralizing the acidic microenvironment to achieve bone protection through promoting osteogenesis and inhibiting osteolysis in a bidirectional manner. This study provides new insights into the treatment of osteoporosis for biomedical and clinical therapies.

Evaluation on pH-dependent thermal gelation performance of chickpea, pea protein, and casein micelles

Concerns about health, the environment, and sustainable food supply have inspired researchers into searching new alternative plant proteins to dairy proteins. This study investigated thermal treatment coupled with pH manipulation (3.0, 5.0, 7.0, and 9.0) on the structural and gelation performance of pea, chickpea protein, and casein. Gel electrophoresis suggested that only specific fractions contributed to disulfide bond-mediated aggregates formation: bovine κ-casein and αs2-casein in casein micelles, acidic and basic legumin subunits in pea and chickpea protein. No protein formed self-standing gels but precipitated in macroscopic flocs at pH 5.0. Casein displayed optimum gel performance at pH 3.0 (storage modulus (G′) of 2596.00 Pa, hardness of 603.47 g, water holding capacity of 94.92%), and transitioned into fluid-like viscous state (G′ < 1, loss tangent >1) under neutral or higher pH conditions. Pea protein did not form self-holding gels but aggregates with globular particles over all test pH. Nevertheless, chickpea protein formed self-standing gels regardless of pH (except 5.0) and peaked gel performance at pH 9.0. Hence, this study indicated considerable potential of casein in acidic thermal gel-based food products and confirmed the promising applications of chickpea protein as an alternative to pea protein across diverse pH conditions, and to casein in neutral and alkaline food gel formulations. In addition to providing scientific insight understanding the effects of thermal treatment coupled with pH manipulation on the performance of plant-based protein and dairy protein, this research sheds light on the promising prospects of incorporating chickpea protein into gel-based food formulations.

Quality Characteristics, Sensory Profiles and Ethylene Production of Stored ‘Abate Fetel’ Pears Sorted at Harvest by Time-Resolved Reflectance Spectroscopy

Time-resolved reflectance spectroscopy (TRS), a nondestructive technique, can help the industry to provide high-quality fruit to encourage pear consumption. The absorption coefficient measured by TRS at 670 nm (μa670) represents a maturity index for pear fruit, with less mature pears high μa670 and more mature low μa670. The aim of this work was to study the quality characteristics, the sensory profiles and the ethylene production of ‘Abate Fetel’ pears sorted at harvest in different TRS maturity classes and stored in different atmospheres. At harvest, 540 pears were measured by TRS for μa670, ranked by μa670 in three maturity classes (less-LeM, medium-MeM and more-MoM mature) and randomized in nine samples according to 1-MCP treatment (treated, control), storage time (4–6 months) and atmosphere (air-NA; CA: 8–12 kPa O2, 1 kPa CO2). Fruits were examined at harvest and after 7 days of poststorage shelf life for skin color, firmness, soluble solids, acidity and ethylene production and were submitted to sensory analysis. At harvest and after storage, MoM pears were less green and showed a higher SSC content than LeM ones. After storage, MoM pears produced less ethylene and were perceived to be firmer (especially in 1-MCP-treated pears), more astringent and less juicy (when stored for 6 months) than LeM ones.

The influence of different gums compared with surfactants as encapsulating stabilizers on the thermal, storage, and low-pH stability of chlorophyllin

Sodium copper chlorophyllin (SCC), with a higher stability and water solubility than chlorophyll, has limited applications in acidic products due to precipitation. We investigated the effect of pectin (PE), carboxymethyl cellulose (CMC), xanthan gum (XG), carrageenan gum (CG), gellan gum (GG), tragacanth gum (TG), gum Arabic (GA), and polysorbate 80 (PS80) on SCC stability in acidic model solutions (pH = 3.5). These stabilizers led to a significant reduction in particle size and zeta-potential compared to control sample. GA (33.3:1), PE (8:1), CMC (4:1), XG (1.33:1), and PS80 (0.67:1) stabilized SCC in acidic systems for 28 days. The FTIR analysis showed that mainly electrostatic and hydrogen bonds between SCC and stabilizers led to a substantial decline in particle size, improving SCC distribution and stability within acidic environment. Thus, XG and CMC could be effectively used for SCC stabilization under acidic solutions where applying PS80 surfactant is a health concern.

LP309 a new strain of Lactiplantibacillus pentosus that improves the lactic fermentation of Spanish-style table olives.

Different varieties of table olives have suitable morphological characteristics that allow them to be processed as Spanish-style green table olives. However, the Campiñesa cultivar presents difficulties when submitted to a lactic fermentation, in spite of being inoculated with dedicated starter cultures such as OleicaStarter. The strategy followed in this study to facilitate the start of lactic fermentation was to reinforce the OleicaStarter culture with the use of the Lactoplantibacillus pentosus Lp309 a strain that enhanced the survival of lactic acid bacteria (LAB) at the beginning of fermentation, reaching final pH values (4.08±0.01), free acidity (1.00±0.01g/100mL of brine), LAB population (6.17±0.09 logCFU/mL), nutrient depletion (0.80±0.09g/kg of pulp), and lactic acid production (11.85±0.72g/L). These values allowed stabilization of the final product, thus complying with the quality and food safety standards established by the Codex Alimentarius for table olives.

Factors Limiting Shelf Life of a Tomato-Oil Homogenate (Salmorejo) Pasteurised via Conventional and Radiofrequency Continuous Heating and Packed in Polyethylene Bottles.

Salmorejo is a tomato-oil cold puree commercialized as a "fresh-like" product requiring mild pasteurisation and chill storage to reach a suitable shelf lifetime. The objective of this study was to study the factors which limit the shelf life of salmorejo pasteurised via conventional or radiofrequency continuous heating, packed in high-density polyethylene bottles, and kept at refrigeration. The pasteurised-chilled salmorejo reached a long shelf life (4 months) compared to that of pasteurised tomato juices or purees. Mesophilic and pathogenic bacteria were easily inhibited in this acidic product. Salmorejo mainly showed oxidative and subsequent sensory changes. Initial enzyme oxidation was associated with some adverse effects (loss of vitamin C and lipid oxidation) at the first month, although there were no sensory implications. Salmorejo remained stable at the physicochemical and sensory levels for the following 3 months, though colour and viscosity changes could be measured with instruments. Between the fourth and fifth month, salmorejo showed clear signs of deterioration, including changes in appearance (slight browning and loss of smooth surface), odour/flavour (loss of freshness and homogenisation), and consistency (thinning trend). The shelf life of salmorejo is limited by long-term oxidative deterioration and their sensory implications.

Self-tuned interfacial charges induced by protonated transition metal heterostructure for efficiently acidic hydrogen evolution reaction

The interfacial engineering provides an effective strategy to develop the noble-free catalysts. However, the long protons migration path and undesirable electrons transportation resistance at the heterointerfaces has hampered advances in highly efficient acidic hydrogen production. Herein, the self-tuned interfacial charges in NiP/HxWO3 binary catalyst are developed for the efficiently acidic water electrocatalysis. Specifically, the interfacial electrons could be automatically tuned and accelerated by a self-modulated work function via the in-situ protonation process of WO3 from the semi-conductor to metallic tungsten bronze (HxWO3) in acidic medium. Moreover, the charge redistribution in NiP/HxWO3 balances the electronic state between surficial Ni sites and P sites, bidirectionally optimizing the hydrogen binding energy over surficial NiP for the favorable H* adsorption and H2 release. A further promotion is achieved by constructing NiP/HxWO3 on carbon fiber fabric to form a hierarchically and seamlessly conductive nanostructure. Impressively, the interfacial charge coordinated NiP/HxWO3 catalyst exhibits outstanding HER activity with an overpotential of 280 mV at the high current density of 500 mA·cm−2 and an excellent long-term stability beyond 110 h in acidic medium, surpassing the most reported catalysts. This work demonstrates an protonation assisted interfacial charge regulation strategy for the development of the efficient multicomponent catalyst.

Molecular Epidemiology genes detection of Klebsiella pneumoniae Clinical Isolates from the Adult Patients with Comorbidities in Baghdad hospitals

Background Klebsiella species is one of the most worldwide opportunistic pathogens in the world that cause infections at multiple sites like lung, urinary tract, bloodstream, wound or surgical site, and brain. Klebsiella pneumoniae has many types of virulence factors that give the bacteria the ability to invade the host and cause infections. Methods A total of (105) human clinical samples were collected from different patients with different cases. Klebsiella pneumonia were isolated from 30 samples. The bacteria were identified by biochemical tests and certified by using VITEK 2 system and genetically by amplify using PCR for 16 rRNA gene. One of the Klebsiella pneumoniae virulence factors is the capsule that is responsible for the macrophage resistance and its also responsible for serotype. So to confirm the strains isolated, PCR Gene detection of, MagA, K2A, RmpA, and Kfu, where (magA, k2A, rmpA, kfu) gens are responsible for capsule synthesis of Klebsiella pneumonia have been done. Results There were 30 strains of Klebsiella pneumoniae were identified. Epidemiological studies show that infections are preceded by gastrointestinal colonization, with the gastrointestinal tract being the most important reservoir for transmission. The primary bacterial isolates were identified based on their cultural, microscopic, and biochemical traits. The API system (API 20E) and VITEK 2 systems were used to confirm the identity of the bacterial isolates. Colony morphology revealed that Klebsiella pneumonia was Gram-negative, non-motile, microscopic straight rods grouped singly or in pairs. Biochemical tests showed that neutral end products prevailed over acidic end products, with Klebsiella producing negative results for indole. The Kligler Iron Agar (KIA) test showed that Klebsiella isolates changed the color of the slant and butt, producing an acidic slant and acid butt, along with gas production. The urease test for Klebsiella distinguishes between Enterobacter and Klebsiella isolates, as Klebsiella can manufacture the urease enzyme. The indole test distinguishes K. pneumonia from K. pneumonia from K. mobiliz. The API 20E system was used for biochemical testing, and the VITEK 2 system was used for identification. The VITEK 2 system was used to test for biochemical and antibiotic susceptibility, and the results supported the findings from morphological and biochemical analyses. PCR amplification was used for molecular detection, and all nine isolates tested positive for the magA and k2A genes. The ferric iron uptake system gene (kfu) and the extracapsular polysaccharide synthesis regulator gene (rmpA) were amplified using specific primer pairs. The VITEK 2 system demonstrated promising outcomes for K. pneumoniae identification. However, standard diagnostic methods are costly and time-consuming. Conclusions Navigating the complex landscape of infectious diseases, collaborative research projects have become indispensable in unraveling the mysteries surrounding pathogens. The project in Baghdad, having stood as a shining example of such collaboration, provided valuable insights into the identification, characterization, and molecular aspects of Klebsiella pneumoniae strains. The findings, have not only contributed to the scientific community's understanding of bacterial infections but also paved the way for enhanced strategies in diagnosis and treatment.

Hot corrosion resistance of Al2O3 nanoparticles reinforced CoNiCrAlY coatings deposited by LPPS and HVOF processes in molten Na2SO4-V2O5 at 850[formula omitted

In this research, satellited CoNiCrAlY/nano-Al2O3 feedstocks with 2 and 4 wt% oxide nanoparticles and conventional CoNiCrAlY powder were deposited through the HVOF and LPPS processes on Inconel 738 substrates. The hot corrosion test was done in molten Na2SO4-55wt.%V2O5 salt at 850 °C for 24 h. The microstructure and phase composition of the as-sprayed and corroded coatings were characterized by the FESEM and XRD. The results showed that by adding Al2O3 nanoparticles in the HVOF CoNiCrAlY coatings up to 4 wt%, the porosity increased from 0.6 to 2.7 vol% and the surface roughness increased from 4.4 to 7.1 μm. By adding Al2O3 nanoparticles in the LPPS CoNiCrAlY coatings up to 4 wt%, the porosity increased from 2 to 3.76 vol%, and the surface roughness increased from 6.1 to 7.5 μm. Penetration of corrosive salt in the conventional and composite HVOF coatings, including 2 and 4 wt% nanoparticles, was obtained as 72, 16, and 140 μm, respectively. Penetration of the corrosive species in the conventional and composite LPPS coatings consisting of 2 and 4 wt% nanoparticles was measured as 91, 125, and 170 μm, respectively. The hot corrosion mechanism was basic and acidic fluxing, creating (Co, Ni)2V2O7, Na(AlO2), CoCo2O4, and NiCr2O4 corrosion products.

Uptake of Breathable Nano- and Micro-Sized Polystyrene Particles: Comparison of Virgin and Oxidised nPS/mPS in Human Alveolar Cells.

Airborne micro- and nanoplastics are widely spread and pose a risk to human health. The third polymer plastic most commonly produced and present in atmospheric fallout is polystyrene (PS). For these reasons and for a more realistic assessment of biological effects, we examined in-home oxidised (ox-, simulating photoaging) nPS/mPS (0.1 and 1 μm), comparing the effects with virgin ones (v-). On human alveolar cells (A549), we quantified the cellular uptake, using FITC-functionalised nPS/mPS, while cytotoxicity, changes in the acidic compartment, ROS production, mitochondrial function, and DNA damage were assessed to study the effects of internalised v- and ox-nPS/mPS. The results showed that the uptake was dose-dependent and very fast (1 h), since, at the lowest dose (1.25 µg/well), it was 20.8% and 21.8% of nPS and mPS, respectively. Compared to v-, significant ROS increases, DNA damage, and mitochondrial impairment were observed after exposure to ox-nPS/mPS. The enhancement of effects due to environmental aging processes highlighted the true potential impact on human health of these airborne pollutants.

Practical results regarding the use of mushrooms in dairy products

&amp;lt;p&amp;gt;The purpose of the study is to present the practical results regarding the introduction of different types of mushrooms in the process of obtaining dairy products. Edible mushrooms have a multitude of health benefits. They contain a series of nutrients, ensure an efficient digestion and they are very good for increasing immunity. Also, according to some laboratory studies, certain mushroom compounds have the ability to annihilate the development of tumor cells. The proposed research focuses on the development of several acidic dairy products with addition of edible mushrooms such as Cantharellus cibarius, Boletus edulis, Pleurotus and Champignon. The developed assortments were compared from a sensorial and physico-chemical point of view with a regular product represented by a dairy assortment in order to note all the aspects that the edible mushrooms bring. In order to obtain the new assortments, we started from the technology of obtaining acid dairy products with usual additions, and after the seeding process, before the product was packaged, the mushrooms were added in powder form. Following the determinations made, the obtained results showed that the dairy products enrichment with mushrooms had a positive impact among consumers and the organoleptic analysis showed that consumers are willing to accept the new varieties developed. From a physico-chemical point of view, in addition to the intake of nutrients and vitamins that mushrooms provide, the developed products performed very well in the laboratory tests, which means that the intake of mushrooms does not change the properties of the ordinary dairy products, but, on the contrary, they improve them.&amp;lt;/p&amp;gt;

Production and Characterization of Kombucha Tea from Different Sources of Tea and Its Kinetic Modeling

This study aimed to investigate the fermentation performance, sugar consumption, pH changes, total phenolic compounds, and antioxidant activity produced using different tea extracts and sugar concentrations and the kinetic characteristics of Kombucha fermentation. Three independent sugar concentrations (10 g/L, 40 g/L, and 70 g/L) were used in the fermentation process. The results showed that the Kombucha culture consumed all sugar in the fermentation medium when the sugar concentration was below a certain threshold, but when the sugar concentration was high, not all substrate was consumed. Sugar consumption values ranged from 48.39 to 55.40 g/L and affected biomass formation, with higher sugar consumption resulting in increased biomass production. The pH decreased during fermentation due to the production of organic acids and microbial by-products, while total acidity increased. Total phenolic compounds increased during fermentation, with the highest concentrations observed in herbal Kombucha teas. Antioxidant activity varied, with some samples showing a decrease in DPPH scavenging ability. Kinetic characterization revealed the relationship between substrate depletion, sugar consumption, total acidity, and phenolic compound production. The results showed that sugar concentration influenced the fermentation kinetics and end-product characteristics of Kombucha tea. Overall, this study provides valuable insights into the fermentation process of Kombucha tea and its impact on various parameters, contributing to the understanding of the factors affecting its quality and health benefits.

In situ measurement and sampling of acidic alteration products at Río Tinto in support of the scientific activity of the Ma_MISS instrument

We describe the procedures and results of a geological field analysis campaign in the Río Tinto area. This geologically/biologically well-documented site with its rock/water/biology interaction represents an ideal open-air laboratory where to collect spectral data and samples useful for testing space instruments. During the field campaign, we collected a large set of VIS-NIR (0.35–2.5 μm) measurements using the ASD FieldSpec4 portable spectrometer both on biosignature-bearing rocks and on alteration hydrated products (sulfates, clays, oxides, etc.). Furthermore, as a comparison to the data collected in the field, we report the results of the micro-Raman analyses carried out in the laboratory on the collected mineral/rock samples. This work was conducted in the framework of the Mars Multispectral Imager for Subsurface Studies (Ma_MISS) instrument that is a miniaturized visible and near-infrared (VIS-NIR) spectrometer (0.5–2.3 μm) devoted to the Martian subsurface exploration and integrated into the drilling system of the ESA Rosalind Franklin rover mission. Ma_MISS will acquire spectral data on the Martian subsurface from the excavated borehole wall. The scientific results obtained by this campaign confirm that the Río Tinto site is important for enriching the scientific community’s grasp on the Martian environment and for obtaining key information on the mineralogical and geochemical evolution of the Martian surface/subsurface. In addition, this work provides crucial preparation for the exploitation and interpretation of the scientific data that the Ma_MISS instrument will supply during the active phase of the mission. This activity is also useful for defining the priorities of the astrobiological objectives on the ground.

Effects of Calcium and Phosphate on Dissolution of Enamel, Dentin and Hydroxyapatite in Citric Acid

The aim was to evaluate the effect of dissolved calcium and phosphate on dissolution rate of enamel, dentin and compressed hydroxyapatite (HA) in citric acid solution as a function of pH. At pH 2.5, dissolution rate of enamel increased significantly by 6% in 20 mmol/L added calcium but, otherwise, dissolution rates of neither enamel, dentin nor HA were significantly affected by 10 or 20 mmol/L calcium. However, enamel dissolution rate was reduced by &gt; 50 mmol/L calcium. At pH 3.25 and 4.0, 10-20 mmol/L calcium inhibited dissolution of enamel by 29-100% and HA by 65-75% but did not affect dentin dissolution. Phosphate (10 or 20 mmol/L) did not inhibit dissolution of enamel, dentin or HA at any pH, but there were increases in dissolution rate of all three substrates at pH 2.5 and, in one test with dentine (at 20 mmol/L phosphate), at pH 3.25. The results suggest that calcium addition to soft drinks and other acidic products such as medications may reduce erosivity against enamel, provided that pH is not too low; that phosphate would not reduce erosivity against enamel; and that neither calcium nor phosphate at these concentrations would reduce erosivity against dentin.&#x0D; Accepted for publication: December 12, 2022&#x0D; Published online: February 21, 2023

Effects of Calcium and Phosphate on Dissolution of Enamel, Dentin and Hydroxyapatite in Citric Acid.

The aim was to evaluate the effect of dissolved calcium and phosphate on dissolution rate of enamel, dentin and compressed hydroxyapatite (HA) in citric acid solution as a function of pH. At pH 2.5, dissolution rate of enamel increased significantly by 6% in 20 mmol/L added calcium but, otherwise, dissolution rates of neither enamel, dentin nor HA were significantly affected by 10 or 20 mmol/L calcium. However, enamel dissolution rate was reduced by > 50 mmol/L calcium. At pH 3.25 and 4.0, 10-20 mmol/L calcium inhibited dissolution of enamel by 29-100% and HA by 65-75% but did not affect dentin dissolution. Phosphate (10 or 20 mmol/L) did not inhibit dissolution of enamel, dentin or HA at any pH, but there were increases in dissolution rate of all three substrates at pH 2.5 and, in one test with dentine (at 20 mmol/L phosphate), at pH 3.25. The results suggest that calcium addition to soft drinks and other acidic products such as medications may reduce erosivity against enamel, provided that pH is not too low; that phosphate would not reduce erosivity against enamel; and that neither calcium nor phosphate at these concentrations would reduce erosivity against dentin.