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[Display omitted] • Acidification, coverage, microbe N conversion, adsorption combined for NH 3 reduction. • Rich H 2 SO 4 and sulfate remained on the vermiculite (VM) after 5 M H+ modification. • Giant CO 2 bubbles due to initial slurry acidification promoted the cover floating. • Vermiculite after 5 M H+ modification performed highest NH 3 reduction (68 %). • NH 4 +/ NH 3 adsorption by VM contributed little (4.7%) to the overall NH 3 mitigation. Animal slurry storage is an important ammonia (NH 3) emission source. Sulfuric acid (H 2 SO 4)-modified vermiculite coverage is a new promising technology for controlling NH 3 emission from slurry storage. However, the underlying mechanisms in controlling the mitigation effect remain unclear. Here, a series of experiments to determine the effect of H 2 SO 4 on the modified vermiculite properties, floating persistence, and NH 3 mitigation effect was conducted. Results showed that abundant H 2 SO 4 and sulfate remained on the outer surface and in the extended inner pores of the vermiculite with acidifying H+ concentrations higher than 5 M. An initial strong instantaneous acidification of surface slurry released rich carbon dioxide bubbles, strengthening cover floating performance. An acidification in the vermiculite cover layer and a good coverage inhibition interacted, being the two leading mechanisms for mitigating NH 3 during initial 40–50 days of storage. The bacterial-amoA gene dominated the conversion of NH 3 to nitrous oxide after 50 days of storage. Vermiculite with 5 M H+ modification reduced the NH 3 emissions by 90 % within the first month of slurry storage and achieved a 64 % mitigation efficiency throughout the 84 days period. With the development of the aerial spraying equipment such as agricultural drones, acidifying vermiculite coverage hold promise as an effective method for reducing NH 3 emission while absorbing nutrients from liquid slurry storage tank or lagoon. This design should now be tested under field conditions. [ABSTRACT FROM AUTHOR]

The modification of substrate concentration and acidification level in inoculum treatment can significantly enhance hydrogen production while reducing costs. Hydrogen production showed a significant variation with food waste (FW) concentration, ranging from 10 to 120 gVS/L. Insufficient acidity at lower FW concentrations of 10, 20, and 40 gVS/L limited hydrogen production to 9.14, 5.70, and 7.78 mL/gVS, respectively, hindering hydrogen-producing bacteria dominance. However, higher FW concentrations facilitated rapid and strong substrate acidification at fermentation onset, effectively inhibiting the non-hydrogen producing bacteria and leading to a vast hydrogen production capacity of 68.63–120.78 mL/gVS. Rapid and substantial FW acidification is vital for effective inoculum treatment, highlighting its crucial role in this study. The findings support the potential use of FW inoculum treatment in generating highly productive microbial communities for hydrogen production. [Display omitted] • Acidification-based inoculum treatment of substrate enables cost-efficient H 2 production. • Variation in hydrogen production observed based on food waste concentrations. • Limited acidity inhibits H 2 production in low food waste concentration groups. • Rapid and strong acidification of substrate is crucial for successful inoculum pretreatment. • Inoculum treatment by food waste can generate productive microbial communities for H 2 production. [ABSTRACT FROM AUTHOR]

[Display omitted] • pH change is necessary for Presynaptic Homeostatic Potentiation at the mouse NMJ. • Extracellular acidification is sufficient for quantal content (QC) upregulation. • Pharmacological inhibition of the PMCA increases QC, contingent on functional ASICs. • Inhibition of PMCA precludes Presynaptic Homeostatic Potentiation. At the vertebrate neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) refers to an increase in neurotransmitter release that restores the strength of synaptic transmission following a blockade of nicotinic acetylcholine receptors (nAChRs). Mechanisms informing the presynaptic terminal of the loss of postsynaptic receptivity remain poorly understood. Previous research at the mouse NMJ suggests that extracellular protons may function as a retrograde signal that triggers an upregulation of neurotransmitter output (measured by quantal content, QC) through the activation of acid-sensing ion channels (ASICs). We further investigated the pH-dependency of PHP in an ex-vivo mouse muscle preparation. We observed that increasing the buffering capacity of the perfusion saline with HEPES abolishes PHP and that acidifying the saline from pH 7.4 to pH 7.2–7.1 increases QC, demonstrating the necessity and sufficiency of extracellular acidification for PHP. We then sought to uncover how the blockade of nAChRs leads to the pH decrease. Plasma-membrane calcium ATPase (PMCA), a calcium-proton antiporter, is known to alkalize the synaptic cleft following neurotransmission in a calcium-dependent manner. We hypothesize that since nAChR blockade reduces postsynaptic calcium entry, it also reduces the alkalizing activity of the PMCA, thereby causing acidosis, ASIC activation, and QC upregulation. In line with this hypothesis, we found that pharmacological inhibition of the PMCA with carboxyeosin induces QC upregulation and that this effect requires functional ASICs. We also demonstrated that muscles pre-treated with carboxyeosin fail to generate PHP. These findings suggest that reduced PMCA activity causes presynaptic homeostatic potentiation by activating ASICs at the mouse NMJ. [ABSTRACT FROM AUTHOR]

Yogurt is made by fermenting milk with 2 lactic acid bacteria, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. To comprehensively understand the protocooperation mechanism between S. thermophilus and L. bulgaricus in yogurt fermentation, we examined 24 combinations of cocultures comprising 7 fast- or slow-acidifying S. thermophilus strains with 6 fast- or slow-acidifying L. bulgaricus strains. Furthermore, 3 NADH oxidase (Nox)-deficient mutants (Δ nox) and one pyruvate formate-lyase deficient mutant (Δ pflB) of S. thermophilus were used to evaluate the factor that determines the acidification rate of S. thermophilus. The results revealed that the acidification rate of S. thermophilus monoculture determined the yogurt fermentation rates, despite the coexistence of L. bulgaricus, whose acidification rate was either fast or slow. Significant correlation was found between the acidification rate of S. thermophilus monoculture and the amount of formate production. Result using Δ pflB showed that the formate was indispensable for the acidification of S. thermophilus. Moreover, results of the Δ nox experiments revealed that formate production required Nox activity, which not only regulated dissolved oxygen, but also the redox potential. The Nox provided the large decrease in redox potential required by pyruvate formate-lyase to produce formate. A highly significant correlation was found between formate accumulation and Nox activity in S. thermophilus. In conclusion, the formate production ability provided by the action of Nox activity determines the acidification rate of S. thermophilus, and consequently, regulates yogurt coculture fermentation. [ABSTRACT FROM AUTHOR]

• Amorphous MnO x was modified by acidification, calcination and Ce modification. • Ce-modified MnO x showed better activity and stability for humid ozone removal. • Ce changed the amount and property of oxygen vacancies in amorphous MnO x. • Ce increased the surface area and oxygen mobility of amorphous MnO x. Manganese-based catalysts were widely developed for catalytic removal of ozone, and the low stability and water inactivation are major challenges. To improve removal performance of ozone, three methods were applied to modify amorphous manganese oxides, including acidification, calcination and Ce modification. The physiochemical properties of prepared samples were characterized, and the catalytic activity for ozone removal was evaluated. All modification methods can promote the removal of ozone by amorphous manganese oxides, and Ce modification showed the most significant enhancement. It was confirmed that the introduction of Ce markedly changed the amount and property of oxygen vacancies in amorphous manganese oxides. Superior catalytic activity of Ce-MnO x can be ascribed to its more content and enhanced formation ability of oxygen vacancies, larger specific surface area and higher oxygen mobility. Furthermore, the durability tests under high relative humidity (80%) determined that Ce-MnO x showed excellent stability and water resistance. These demonstrate the promising potential of amorphously Ce-modified manganese oxides for catalytic removal of ozone. [Display omitted] [ABSTRACT FROM AUTHOR]

Anaerobic acidification of pressed sugar beet pulp (PSBP) is a promising strategy for the transition towards a circular economy. In this work, volatile fatty acids were produced by anaerobic acidification of PSBP and subsequently converted to mcl-polyhydroxyalkanoates. The results point to mesophilic acidification as superior to thermophilic one. At the same time, the pH regulated at the value of 6.0 showed a decisive advantage over both the pH of 7.0 and the lack of pH regulation. Furthermore, the conditions with a hydraulic retention time (HRT) of 10 days significantly outperformed those with an HRT of 6 days. The best-performing process (mesophilic, pH controlled at 6, HRT of 10 days) was successfully scaled up to a 250 L reactor, reaching a volatile fatty acid (VFA) concentration of up to 27.8 g L-1. Finally, the produced VFA were investigated as feedstock for mcl-PHA producers, Pseudomonas citronellolis and Pseudomonas putida. Both strains grew and produced PHA successfully, with P. citronellolis reaching a biomass of 15.6 g L-1 with 38% of mcl-PHA, while P. putida grew to 15.2 g L-1 with a polymer content of 31%. This study proves that acidified PSBP is a valuable feedstock for mcl-PHA production and an important approach to developing biorefineries. [Display omitted] • Optimization of acidification process for pressed sugar beet pulp at lab-scale. • Successful scale-up to 250 L reactor, achieving 27.8 g L− 1 of volatile fatty acids (VFAs). • Production of biomass containing 38% mcl-PHA using acidified pressed sugar beet pulp. [ABSTRACT FROM AUTHOR]

Valsa mali is a destructive phytopathogenic fungus that mainly infects apple and pear trees. Infection with V. mali results in host tissue acidification via the generation of citric acid, which promote invasion. Here, two plasma membrane H+-ATPases, VmPma1 and VmPma2 , were identified in V. mali. The VmPma1 deletion mutant (∆VmPma1) displayed higher intracellular acid accumulation and a lower growth rate compared to the wild type. In contrast, the VmPma2 deletion mutant (∆VmPma2) showed no obvious phenotypic differences. Meanwhile, loss of VmPma1 , but not VmPma2 , in V. mali led to a significant decrease in growth under acidic or alkaline conditions compared with WT. More importantly, ∆VmPma1 showed a greater reduction in ATPase hydrolase activity and acidification of the external environment, more sensitivity to abiotic stress, and weaker pathogenicity than ∆VmPma2. This evidence indicates that VmPma1 is the main gene of the two plasma membrane H+-ATPases. Transcriptomic analysis indicated that many metabolic processes regulated by VmPma1 are strictly pH-regulated. Besides, we identified two genes (named VmAgn1p and Vmap1) that contribute to the pathogenicity of V. mali by differentially regulating external acidification capacity. Overall, our findings show that VmPma1 plays a pivotal role in pathogenicity by affecting the acidification of V. mali. [ABSTRACT FROM AUTHOR]

Transmembrane kinases (TMKs) and Feronia (FER) belong to the leucine-rich repeat receptor-like kinase family. Recent studies reveal that they coordinate plant growth and stress responses by regulating the balance between acidification and alkalization and crosstalk between auxin and abscisic acid, revealing a dynamic equilibrium in the regulation of the TMK-FER module in plants. [ABSTRACT FROM AUTHOR]

This research demonstrates a palm kernel shell gasification system for producing fuel gas, also known as producer gas. Using air as an oxidant, the gasification process converts palm kernel shells into fuel gas which contains combustible gases, such as hydrogen, carbon monoxide, and methane with nitrogen dominating the composition of the gas. This fuel gas can supply heat via direct combustion or generate electricity for fossil fuel substitution of an internal combustion engine. As a biomass-derived gas, the fuel gas is characterized as carbon-neutral inherently. During the conversion process, the system needs electricity to power the screw feeder, air blowers, and cooling-water pumps, and to rotate the gasifier's bottom plate to take the char out. Based on the experiments, mass balance, and energy balance calculations, this study examines the global warming, acidification, and eutrophication potential using the openLCA v1.10.3 software and Environmental Footprint (MID-Point indicator) database for impacts assessment when the system is operated in Indonesia and Malaysia with various electricity sources. It is found that the feedstock contributed most of the global warming potential and eutrophication potential, while the electricity dominated the acidification potential. This study recommends operation at a lower equivalent ratio to reduce environmental impacts. • Air gasification of palm kernel shells to produce fuel gas was conducted at a 25 kg/h gasifier capacity. • This study assessed the Global Warming, Eutrophication, and Acidification Potentials of the gasification process. • The effects of equivalent ratios on the environmental impacts were evaluated using a life cycle approach. • Palm kernel shells acquisition showed significant environmental impacts. • The scenarios to improve the process included variations of feedstock sources and electricity generation methods. [ABSTRACT FROM AUTHOR]

Yeast vacuoles are acidified by the v-type H+-ATPase (V-ATPase) that is comprised of the membrane embedded VO complex and the soluble cytoplasmic V1 complex. The assembly of the V1-VO holoenzyme on the vacuole is stabilized in part through interactions between the VO a-subunit ortholog Vph1 and the lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). PI(3,5)P2 also affects vacuolar Ca2+ release through the channel Yvc1 and uptake through the Ca2+ pump Pmc1. Here, we asked if H+ and Ca2+ transport activities were connected through PI(3,5)P2. We found that overproduction of PI(3,5)P2 by the hyperactive fab1T2250A mutant augmented vacuole acidification, whereas the kinase-inactive fab1EEE mutant attenuated the formation of a H+ gradient. Separately, we tested the effects of excess Ca2+ on vacuole acidification. Adding micromolar Ca2+ blocked vacuole acidification, whereas chelating Ca2+ accelerated acidification. The effect of adding Ca2+ on acidification was eliminated when the Ca2+/H+ antiporter Vcx1 was absent, indicating that the vacuolar H+ gradient can collapse during Ca2+ stress through Vcx1 activity. This, however, was independent of PI(3,5)P2, suggesting that PI(3,5)P2 plays a role in submicromolar Ca2+ flux but not under Ca2+ shock. To see if the link between Ca2+ and H+ transport was bidirectional, we examined Ca2+ transport when vacuole acidification was inhibited. We found that Ca2+ transport was inhibited by halting V-ATPase activity with Bafilomycin or neutralizing vacuolar pH with chloroquine. Together, these data show that Ca2+ transport and V-ATPase efficacy are connected but not necessarily through PI(3,5)P2. [ABSTRACT FROM AUTHOR]

• Mycorrhizal fungi stimulate growth of Juniperus communis. • The effect of mycorrhiza on J. communis correlates with soil Ca, Mg and Na. • The effect of mycorrhizal fungi on J. communis was not associated with pH. High nitrogen (N) deposition rates can cause soil eutrophication and acidification causing harmful effects to many plant species. One species that seems to be affected is Juniperus communis , populations of which are declining in Western Europe, due to a lack of regeneration. This is primarily caused by limited seedling recruitment and low viable seed production; factors that have both been attributed to increased levels of N deposition. J. communis sapling performance could be dependant on mycorrhizal fungi (MF) in their roots , but how – and under what conditions – MF contribute to the performance of J. communis has not been studied before. Here we experimentally tested the effect of MF on J. communis cuttings along an acidity gradient in situ. To manipulate the interaction with MF, we used ingrowth cores, effectively allowing for root-MF interactions or strongly reducing these. After six months we measured growth and needle nutrient concentrations of cuttings with a normal or reduced mycelial network. MF had a positive effect on absolute growth of our cuttings. However, this effect was weakened as soil Mg2+, Ca2+ and Na+ concentrations declined. Soil pH itself was not directly associated with the effect of MF on J. communis. MF also decreased needle phosphorous concentrations, most likely because the increased plant growth by MF diluted its concentration in the plants. We conclude that MF stimulate the performance of J. communis , but that leaching of cations, accelerated by N deposition, negatively affects their mutualism and thereby the performance of J. communis saplings. This highlights the potential positive role of MF in effective conservation and restoration efforts of J. communis habitats in Western Europe and the importance of prioritising the reduction of ongoing eutrophication and acidification. [ABSTRACT FROM AUTHOR]

During anaerobic fermentation of food waste (FW), acidification destabilizes the fermentation, and affects methane production. This study analyzed the anaerobic fermentation of FW to produce acid and gas under different food-to-microorganism (F/M) ratios after adding zero-valent iron (ZVI) to improve the performance of anaerobic fermentation. Results showed that when the F/M was 2, ZVI had a significant promoting effect on acetic acid, ethanol, and butyric acid production but significantly reduced propionic acid production. Moreover, optimal acid production was observed when 6 g L−1 ZVI powder was added. Furthermore, at ≥6 g L−1 ZVI, the biodegradation rate increased to >70%, and the cumulative methane production of the load increased to >440 mg L−1. Therefore, these results indicate that adding ZVI to FW digestion under different F/M ratios can increase methane production in an anaerobic fermentation system by promoting acetic acid production and reducing propionic acid production. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe 3 O 4 accelerated acetate production in anaerobic digestion of food waste. • The maximum acetate yield was enhanced by 79 % with 10 g/L of Fe 3 O 4 addition. • Fe 3 O 4 enhanced anaerobic hydrolysis/acidification and degradation of propionate. • Fe 3 O 4 promoted enzyme activities and electron transfer in hydrolysis/acidification. • Fe 3 O 4 could act as an electron acceptor and contribute to acetic acid production. Fe 3 O 4 supplementation has been reported as a high-efficient approach to enhance biogas production in anaerobic digestion (AD). Volatile fatty acids (VFAs), especially acetic acid (HAc), are considered as important products in acidification process of AD. However, the possible mechanisms involved in promotion effect of Fe 3 O 4 on HAc production in hydrolysis and acidification processes of AD have not been comprehensively studied. This study first investigated the promotion effect of Fe 3 O 4 on hydrolysis, acidogenesis and acetogenesis stages of AD and proposed the underlying mechanisms, using food waste (FW) as the feedstock, which is considered as the most suitable substrate for VFAs production. Results indicated that the HAc production (77.38 g-C/kg-VS) was enhanced by 79 % in AD of FW with addition of 10 g/L Fe 3 O 4. The duration to reach the maximum HAc production was also shortened from 14 days to 10 days. The AD tests using model substrates revealed that Fe 3 O 4 enhanced hydrolysis, acidogenesis, and degradation of propionic acid, thus resulting in enhanced HAc production. The enhanced activities of hydrolytic and acid-forming enzymes, and electron transport system (ETS) with Fe 3 O 4 addition further demonstrated its function as an electron acceptor to stimulate electron transfer and accelerate microbial metabolisms in AD, which contributed to the enhanced HAc production from FW. [ABSTRACT FROM AUTHOR]

This anaerobic digestion (AD) study investigated the effect of inoculum to substrate ratio (ISR 4.00 to 0.25) on viability of methanogenesis using simulated food waste as substrate. Given the complexity of the AD process, this study considered the interdependency of AD parameters and their effect on biogas production, as the digestion progressed. Maximum methane production was between ISR 2.00 (139 ± 10 ml CH 4 /g VS added) and 1.00 (152 ± 12 ml CH 4 /g VS added); further decreases in ISR were found to result in system acidification. Under acidogenic conditions (ISR≤0.5) pH and the volatile fatty acid (VFA) profile were found to be strongly dependent on the ISR. In contrast to ISR 0.25, ISR 0.50 showed reverse beta oxidation, which resulted in increased concentrations of medium chain VFAs over the digestion period. Maximum total VFA (TVFA) concentrations that the system could survive with reversible acidification (ISR 1.00) was found to be 17.52 ± 0.02 g/l, whereas the maximum TVFA production was found to be 29.25 ± 0.73 g/l for ISR 0.50. Uniquely, this study also reports up to 55% anaerobic degradation of lignin in acidified reactors with ISR 0.25, which based on existing literature, points towards the involvement of specific bacterial strains. [ABSTRACT FROM AUTHOR]

• There is no need of preserving 24 h urine samples when stored at room temperature for up to 72 h. • This finding facilitates sample collection and may improve patient compliance and safety. • If needed, preservation may be done only after collection and prior to analysis. Recommendations on the optimal preservation of 24 h urine for the metabolic work-up in urolithiasis patients are very heterogeneous. In case two such tests with different storage condition recommendations are being analysed, multiple collections would be needed, challenging especially elderly and very young patients. We therefore aimed to evaluate the stability of urine constituents under different storage conditions. We collected urine samples from ten healthy volunteers and prepared aliquots to be stored either at room temperature or 4 °C. Some aliquots were preserved using hydrochloric acid prior to storage, some thereafter, some using the BD Urine preservation tube and some were not preserved at all. Storage duration was 0, 24, 48 or 72 h. In all samples calcium, magnesium, phosphorus, creatinine, oxalate, citrate and uric acid were measured and compared to the according reference sample. We could not find any significant deviation for any of the analytes and preanalytical treatment conditions compared to the associated reference sample. Preservation of 24 h urine for the metabolic evaluation in stone formers might not be necessary for sample storage up to 72 h. [ABSTRACT FROM AUTHOR]

Peruvian bays that are home to aquatic organisms of commercial interest are increasingly affected by hypoxia and low pH events. These stressors produce unfavorable conditions for the aquatic fauna, leading to mass mortality events. In this study, we evaluated the ecophysiological responses of the scallop Argopecten purpuratus exposed to moderate hypoxia (20% DO saturation) and low pH (OA, pH 7.4) using a 2 × 2 factorial design. We found that a 51-day exposure to low pH (OA treatment) had greater negative effects on A. purpuratus performances than hypoxia (lower survival and decreased clearance and calcification rates), but stimulated early gonad maturation. The survival rate was 1.3-fold higher under hypoxia than under acidic treatment. The interaction between hypoxia and low pH had an antagonistic effect on survival, since the combined treatment (HOA) resulted in lower scallop mortality than the single stress treatments. Calcification was negatively affected by all stress treatments, whereas hypoxia and OA both stimulated gametogenesis. OA treatment resulted in higher frequencies of previtellogenic and vitellogenic oocytes, greater gonad coverage area, and lower frequency of atretic oocytes, suggesting higher reproductive potential. HOA was positively related to oocyte development and high frequency of post-vitellogenic and atretic oocytes. These results suggest that, due to hypoxia and low pH, feeding is reduced and energy allocation prioritizes scallop gonad maturation. This trend would have negative effects on scallop growth and calcification, while increased reproduction under environmental stress could mitigate the effect on recruitment. • Scallops showed physiological adaptations to survive and reproduce under medium-term exposure. • The most pronounced impact of hypoxia and low pH were on clearance and calcification rates. • The combined effect of hypoxia and low pH produced relatively high survival (>70%). • Hypoxia and low pH generated early gonad development and high reproductive potential. [ABSTRACT FROM AUTHOR]

• Colocalization of Fe and P was observed in the root Fe plaque. • Localized rhizospheric acidification facilitated the Ca-bound P solubilization. • An increase in phosphatase activity promoted the organic P mineralization. • P-cycling microbial communities improved rhizospheric P mobilization. Rhizoremediation of wetland plants is an environmentally friendly strategy for sediment phosphorous (P) removal, the basic underlying principle of which is the complex interactions between roots and microorganisms. This study investigated the immobilization and mobilization mechanisms of P in the rhizosphere of wetland plants using high-resolution spatial visualization techniques and metagenomic sequencing. Two-dimensional visualization of the spatial distribution of P, iron (Fe) and manganese (Mn) indicated that the sequestration of Fe-oxides rather than Mn-oxides caused the depletion of labile P, resulting in an increase in the Fe-adsorbed P fraction. Plants altered the rhizospheric environments and P-cycling microbial community to mobilize low-availability P from sediments. Mineral P solubilization and organic P mineralization were enhanced by local acidification and increased phosphatase activity, respectively. Microbial P mobilization also increased with increasing relative abundances of P solubilization and mineralization genes (gcd and phnW) and decreasing P transportation genes (ugpA, ugpB , and pit) genes in the rhizosphere. These processes led to the remobilization of 10.04 % of inorganic P, and 15.23 % of organic P, in the rhizosphere during the incubation period. However, the resupply of P via the above processes did not compensate for the depletion of rhizospheric P via root uptake and mineral sequestration. Our results provide novel insights into the mechanisms of rhizospheric P cycling, which will help to inform future phytoremediation strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Global climate changes induce substantial alterations in the marine system, including ocean acidification (OA), desalination and warming of surface seawater. Here, we examined the combined effects of OA and reduced salinity under different temperatures on the growth and photosynthesis of the diatom Skeletonema costatum. After having been acclimated to 2 CO 2 concentrations (400 μatm, 1000 μatm) and 2 salinity levels (20 psu, 30 psu) at temperature levels of 10 °C and 20 °C, the diatom showed enhanced growth rate at the lowered salinity and elevated p CO 2 irrespective of the temperature. The OA treatment increased the net photosynthetic rate and biogenic silica (Bsi) contents. Increasing the temperature from 10 to 20 °C raised the net photosynthetic rate by over twofold. The elevated p CO 2 increased the net and gross photosynthetic rates by 20%–40% and by 16%–32%, respectively, with the higher enhancement observed at the higher levels of salinity and temperature. Our results imply that OA and desalination along with warming to the levels tested can enhance S. costatum 's competitiveness in coastal phytoplankton communities under influence of future climate changes. • This study aims to investigate the combined effects of pH (400 μatm and 1000 μatm), temperature (10 °C, 20 °C), and salinity (20 psμ, 30 psμ) on the diatom S. costatum. • In this study, we investigated the effects of ocean acidification and seawater desalination on Skeletonema costatum in varying seasonal temperatures. • We found that ocean acidification and seawater desalination promoted the growth of S. costatum under the simulated conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • AAMBR at pH 5.0 successfully generated VFAs from municipal wastewater. • The generated VFAs consisted of acetic acid, propionic acid, and butyric acid. • The VFAs concentration was 1772 mg/L with a production efficiency of 63 %. • A pH of 5.0 is preferable for the AAMBR compared to a pH of 10.0. To address the low-carbon treatment requirements for municipal wastewater, a novel anaerobic acidification membrane bioreactor (AAMBR) was developed for recovering organic matter in terms of volatile fatty acids (VFAs). While the AAMBR successfully generated VFAs from municipal wastewater through forward osmosis (FO) membrane concentration, its operation was limited to a single pH value of 10.0. Here, performance of the AAMBR operating at acidic condition was evaluated and compared with that at alkaline condition. The findings revealed that the AAMBR with pH 5.0 efficiently transformed organic matter into acetic acid, propionic acid, and butyric acid, resulting in a VFAs yield of 0.48 g/g-COD feed. In comparison with the AAMBR at pH 10.0, this study achieved a similar VFAs yield, a lower fouling tendency, a lower loss of nutrients and a lower controlling cost. In conclusion, this study demonstrated that a pH of 5.0 is optimal for the AAMBR treating municipal wastewater. [ABSTRACT FROM AUTHOR]

• We investigated the impacts of bedding and outdoor runs on pig welfare and environment. • Bedding improved aspects of pig welfare, e.g. exploratory behaviour and oral stereotypies. • Acidification was higher on farms with bedding due to emissions from farm yard manure. • Global warming/freshwater eutrophication did not significantly differ due to farm variability. • Manure management innovations are needed to reduce emissions on farms with bedding. Providing bedding or access to an outdoor run are husbandry aspects intended to improve pig welfare, which is currently financially supported through animal welfare schemes in several European countries. However, they may significantly affect the environment through changes in feed efficiency and manure management. Therefore, the aim of this paper was to compare farms differing in animal welfare relevant husbandry aspects regarding (1) the welfare of growing-finishing pigs and (2) environmental impact categories such as global warming (GW), acidification (AC), and freshwater (FE) and marine eutrophication (ME), by employing an attributional Life Cycle Assessment. We collected data on 50 farms with growing-finishing pigs in seven European countries. Ten animal-based welfare indicators were aggregated into three pig welfare indices using principal component analysis. Cluster analysis of farms based on husbandry aspects resulted in three clusters: NOBED (31 farms without bedding or outdoor run), BED (11 farms with bedding only) and BEDOUT (eight farms with bedding and outdoor run). Pigs on farms with bedding (BED and BEDOUT) manipulated enrichment more often (P < 0.001), pen fixtures less frequently (P = 0.003) and showed fewer oral stereotypies (P < 0.001) than pigs on NOBED farms. There were fewer pigs with a short(er) tail on farms with than without bedding (P < 0.001). Acidification of BEDOUT and BED farms was significantly higher (compared to NOBED farms P = 0.002) due to higher ammonia emissions related to farmyard manure. Also, BEDOUT farms had higher ME than NOBED farms (P = 0.035). There were no significant differences regarding GW and FE between husbandry clusters, due to the large variability within clusters regarding feed composition and conversion. Therefore, both husbandry aspects associated with improved animal welfare have a significant influence on some environmental impacts, such as acidification and marine eutrophication. Nevertheless, the large variation within clusters suggests that trade-offs may be minimised through e.g. AC and ME. [ABSTRACT FROM AUTHOR]

We employed a meta-analysis to determine if the presumed resilience of decapods to ocean acidification extends to all biological aspects, environments, and life stages. Most response categories appeared unaffected by acidification. However, certain fitness-related traits (growth, survival, and, to some extent, calcification) were impacted. Acid-base balance and stress response scaled positively with reductions in pH, which maintains homeostasis, possibly at the cost of other processes. Juveniles were the only stage impacted by acidification, which is believed to reduce recruitment. We observed few differences in responses to acidification among decapods inhabiting contrasting environments. Our meta-analysis shows decapods as a group slightly to moderately sensitive to low pH, with impacts on some biological aspects rather than on all specific life stages or habitats. Although extreme pH scenarios may not occur in the open ocean, coastal and estuarine areas might experience lower pH levels in the near to medium future, posing potential challenges for decapods. Meta-analysis of the effect of ocean acidification on decapods. Right: effect of acidification on main categories (physiology, behavior, life history) of life stages (embryos, larvae, juvenile, adults) of decapods. Left: effect of acidification on secondary categories. The slopes correspond to the relationship between effect sizes and ∆pH. Arrows show the effect and its direction, equal symbol (=) depicts the absence of net changes. The photo of Ovalipes trimaculatus was kindly provided by Dr. Nahuel Farias. [Display omitted] • Predicted level of ocean acidification is a threat for calcifier marine invertebrates. • Decapods, thought debatable, are presumably resilient. • Our meta-analysis revealed few impacts that mainly vary across biological traits. • Effect sizes little vary depending on the life stages and environments. [ABSTRACT FROM AUTHOR]

• Acidification can occur during storage of Congou black tea. • Aroma enhancement process (AEP) accelerates acidification of black tea during storage. • AEP promotes conversion of Phenylalanine and glucose to oxalic acid, quinic acid, etc. • AEP also changes tea soup composition and increases acidification during storage. Acidification of aroma-enhanced black tea during storage was studied. UPLC-Q-TOF/MS (Ultra Performance Liquid Chromatography and Quadrupole-Time of Flight Mass Spectrometer) and HPLC (High-Performance Liquid Chromatography) analysis of non-volatile substances and organic acids revealed a decrease of soluble sugars and amino acids in aroma-enhanced black tea, while an increase in organic acids such as oxalic acid, malic acid and quinic acid. Further in vitro experiments indicated that the acidification of aroma-enhanced tea during storage can be attributed to decomposition of sugars and amino acids by heating, oxidation of aromatic aldehydes. Meanwhile, the amino acids, catechins, soluble sugars and flavonoids that constitute the taste of black tea are further reduced, changing the taste composition of tea infusion and further increasing its acidity. This study revealed the reasons for black tea acidification during aroma enhancement and storage and provided a theoretical basis for improving black tea quality. [ABSTRACT FROM AUTHOR]

• We present novel findings of the angatonistic effects of Alexandrium catenella on phytoplankton under warming and acidification. • Experiments targeted three species and tested for density-dependent effects. • Growth inhibition increased under warming and acidification on Rhodomonas salina and Tetraselmis. • There was no antagonistic effect on the target diatom (Thalassiosira weissflogii) under ambient or OWA conditions. • Growth inhibition under OWA conditions may alter phytoplankton community composition by affecting some groups but not others. There is a concern that harmful algal bloom (HAB) species may increase under climate change. Yet, we lack understanding of how ecological interactions will be affected under ocean warming and acidification (OWA) conditions. We tested the antagonistic effects of three strains of the dinoflagellate HAB species Alexandrium catenella on three target species (the chlorophyte Tetraselmis sp., the cryptomonad Rhodomonas salina , and the diatom Thalassiosira weissflogii) at various biomass ratios between species, at ambient (16 °C and 400 µatm CO 2) and OWA (20 °C and 2000 µatm CO 2) conditions. In these experiments the Alexandrium strains had been raised under OWA conditions for ∼100 generations. All three non-HAB species increased their growth rate under OWA relative to ambient conditions. Growth rate inhibition was evident for R. salina and Tetraselmis sp. under OWA conditions, but not under ambient conditions. These negative effects were exacerbated at higher concentrations of Alexandrium relative to non-HAB species. By contrast, T. weissflogii showed positive growth in the presence of two strains of Alexandrium under ambient conditions, whereas growth was unaffected under OWA. Contrary to our expectations, A. catenella had a slight negative response in the presence of the diatom. These results demonstrate that Alexandrium exerts higher antagonistic effects under OWA compared to ambient conditions, and these effects are species-specific and density dependent. These negative effects may shift phytoplankton community composition under OWA conditions. [ABSTRACT FROM AUTHOR]

Here, we explicitly define a half-cell reaction approach for pH calculation using the electrode couple comprised of the solid-state chloride ion-selective electrode (Cl-ISE) as the reference electrode and the hydrogen ion-selective ion-sensitive field effect transistor (ISFET) of the Honeywell Durafet as the hydrogen ion H + -sensitive measuring or working electrode. This new approach splits and isolates the independent responses of the Cl-ISE to the chloride ion Cl − (and salinity) and the ISFET to H + (and pH), and calculates pH directly on the total scale pH total EXT in molinity (mol (kg-soln)−1) concentration units. We further apply and compare pH total EXT calculated using the half-cell and the existing complete cell reaction (defined by Martz et al. (2010)) approaches using measurements from two SeapHOx sensors deployed in a test tank. Salinity (on the Practical Salinity Scale) and pH oscillated between 1 and 31 and 6.9 and 8.1, respectively, over a six-day period. In contrast to established Sensor Best Practices, we employ a new calibration method where the calibration of raw pH sensor timeseries are split out as needed according to salinity. When doing this, pH total EXT had root-mean squared errors ranging between ±0.0026 and ±0.0168 pH calculated using both reaction approaches relative to pH total of the discrete bottle samples pH total disc. Our results further demonstrate the rapid response of the Cl-ISE reference to variable salinity with changes up to ±12 (30 min)−1. Final calculated pH total EXT were ≤±0.012 pH when compared to pH total disc following salinity dilution or concentration. These results are notably in contrast to those of the few in situ field deployments over similar environmental conditions that demonstrated pH total EXT calculated using the Cl-ISE as the reference electrode had larger uncertainty in nearshore waters. Therefore, additional work beyond the correction of variable temperature and salinity conditions in pH calculation using the Cl-ISE is needed to examine the effects of other external stimuli on in situ electrode response. Furthermore, whereas past work has focused on in situ reference electrode response, greater scrutiny of the ISFET as the H + -sensitive measuring electrode for pH measurement in natural waters is also needed. • Electrode responses are split out and isolated using half reactions. • A new approach for pH calculation using half reactions is explicitly defined. • pH calculation uses single ion activity coefficients for the chloride and hydrogen ions. • This new pH calculation approach is optimized for salinities between 0.105 and 35. • pH can now be calculated directly on the total scale in molinity (mol (kg soln)−1). [ABSTRACT FROM AUTHOR]

[Display omitted] • It is unknown if N enrichment in tropical urban arable soils will decline soil fertility. • Surprisingly N contents and stocks decreased with increasing urbanisation intensity. • SOC, Ca2+, K+, Na+, CEC e , and soil pH increased with urbanisation intensity. • Strong SOC-N-exchangeable bases relations suggest converged sources. • Remarkably TN did not adversely affect soil fertility indicators. Urbanisation induces nitrogen (N) enrichment in tropical soils. This enhances soil acidification, leading in turn to a decrease in effective cation exchange capacity (CEC e) and base saturation (BS e). Here, we investigated if and how these effects of urbanisation-induced N inputs affect the soils of tropical urban agroecosystems. Our aim was to quantify the impact of urbanisation intensity (UI) on total N (TN) contents and stocks, and to detect possible adverse N effects on soil pH, CEC e , and exchangeable bases in rainfed urban arable soils of Kumasi, a tropical city in Ghana, West Africa. We analysed 618 topsoil samples (0–10 cm) from arable fields within the urban perimeter, categorised into four classes forming a gradient from low to high UI. For baseline comparison, 9 samples each from both rural arable fields and an urban forest were included. Urban arable soils generally had higher TN levels than their rural counterparts. Among the urban arable soils however, TN levels decreased with increasing UI, possibly as crop production and related N export through harvest intensified. Conversely, increasing UI correlated with increased levels of exchangeable Ca2+, K+, and Na+. No adverse N effect on soil pH, CEC e , and BS e was detected. This could be explained with the strong TN-SOC relationship (R2 ≥ 0.9), and an increasingly strong relationship between exchangeable bases and TN and SOC (R2 = 0.5–0.8) with increasing UI. These relationships suggested a major common source of TN, SOC, and exchangeable bases. As the soils are neither chemically fertilised nor limed, these findings supported earlier studies that this source is provided by dumped biodegradable household waste, charred matter, ash, and construction materials. We concluded that soil N enrichment through these materials in Kumasi is accompanied by abundant bases in the same materials, which overcompensate any theoretic acidification. Our findings imply that not only can the fertility of tropical urban arable soils in cities like Kumasi be maintained, but also that the crops and ground water may not be at risk from the mobilisation of trace elements and heavy metals due to the hindered soil acidification. [ABSTRACT FROM AUTHOR]

Reef fishes in the California Current Ecosystem have evolved in habitats affected by seasonally variable, episodic upwelling of high p CO 2 (acidified, low pH) and low dissolved oxygen (deoxygenated) water, which suggests that these fishes might exhibit resilience to ocean acidification (OA) and deoxygenation. Yet, how the fitness of these fish are affected by natural variability in pH and DO over short time scales remains poorly understood, as do the effects of longer-term trends in pH and DO driven by climate change. We conducted a complementary suite of experiments to study the effects of acidification and deoxygenation on the critical swimming speed (U crit) of juvenile copper (Sebastes caurinus) and black (S. melanops) rockfish collected from nearshore habitats in an ocean acidification "hotspot" off Northern California. We consistently observed that U crit declined more strongly in response to deoxygenation than to acidification, at least under ranges of these stressors consistent with current conditions and plausible future scenarios, and that reduction in swimming performance reflected additive rather than synergistic responses to concurrent exposure. Reductions in swimming performance manifested quickly–on the scale of hours–in response to exposure to elevated p CO 2 /reduced DO, yet are reversible: swimming performance of juvenile rockfish recovers within a matter of days, and perhaps much more quickly, after acidified/deoxygenated conditions have subsided. Insights from this study address potential effects of variability in upwelling intensity at event and seasonal scales for nearshore rockfishes and contribute to our understanding of fish responses to future ocean conditions driven by ongoing climate change. • Swimming ability of juvenile rockfishes declined during acute and chronic exposure to deoxygenation and acidification. • Critical swimming speed of juvenile rockfish was more sensitive to deoxygenation than to acidification. • The effects of acidified and deoxygenated conditions on juvenile rockfish swimming ability manifest rapidly (hours to days). • Swimming performance of juvenile rockfish recovered after upwelling-event acidified/deoxygenated conditions had subsided. • Despite early life history differences, black and copper rockfish had similar sensitivity to acidification and deoxygenation. [ABSTRACT FROM AUTHOR]

Nucleosides and nucleotides at μM concentrations stimulated a 300% increase in acid secretion in HepG2 cells, which was quantitatively accounted for as increased export of lactate generated by glycogenolysis. Agonist selectivity encompassed nucleosides and nucleotides for all 5 natural nucleobases and, along with antagonist profiles, was inconsistent with a role for purinergic receptors in mediating this activity. Agonist catabolism did not contribute significantly to either low selectivity or lactate production. Lactate production was driven by an increase in ATP turnover of as much as 56%. For some agonists, especially adenosine, ATP turnover decreased precipitously at mM concentrations, correlating with known adenosine-stimulated apoptosis. We propose that nucleoside/nucleotide agonists induce a futile energy cycle via a novel mechanism, which results in increased ATP turnover and initiates a continuum of events that for some agonists culminates in apoptosis. • Purinergic agonists induce up to 300% increase in acid secretion in HepG2 cells at μM concentrations. • Agonist selectivity is very low and encompasses all natural nucleosides and nucleotides. • Acid secretion is driven by increased ATP turnover by as much as 56% over control levels. • Subsequent precipitous decline in ATP turnover at mM concentrations correlates with apoptosis. [ABSTRACT FROM AUTHOR]

[Display omitted] • PWPI and AWPI showed different gelling behaviors under GDL acidification. • The addition of 0.6–1.2% GDL significantly enhanced the strength of PWPI gels. • PWPI gels with 1.2% GDL showed a denser and more uniform microstructure. • Acidification with different amounts of GDL can modulate the texture of PWPI gels. • Disulfide bonds and hydrophobic interactions were the main forces in the gels. The gelation of walnut protein isolates has not been extensively studied, mainly due to their inherent poor dispersity. This study investigated the gelation of alkaline-extracted walnut protein isolates (AWPI) and phosphorylated walnut protein isolates (PWPI) induced by heat treatment with glucono-δ-lactone (GDL) acidification, focusing on the impact of GDL concentrations on microstructure, rheology, and texture of the resulting gels. The PWPI gel exhibited lower hardness but a smoother structure than the AWPI gel. Notably, acidification with GDL (0.6–1.2%) significantly increased the stiffness of PWPI gels, increasing storage modulus and yield stress 10–50 times, while weakening AWPI gels. Varying concentrations of GDL effectively modulated the microstructure of the PWPI gels, leading to the altered texture (from a soft-solid state to a well-self-supporting stiff-solid gel) and water holding capacity (from approximately 46% to 85%). Additionally, hydrophobic interactions and disulfide bonds were identified as the primary forces involved in the gels. [ABSTRACT FROM AUTHOR]

• CaCl 2 can enhance markedly the structural strength of self-thickening agent TZXJ network aggregates. • Self-thickening agent TZXJ possesses a strong salt thickening effect and can resist saturated concentration of CaCl 2 solution. The effect of CaCl 2 on the micromorphology of a self-thickening agent (TZXJ) was investigated. This study involved analyzing the compositional changes in acid solutions during acid–rock reactions. It combined dynamic light scattering and viscosity testing to confirm that the presence of CaCl 2 enhances the aggregation strength of the TZXJ network structure in acid solutions. This enhancement is macroscopically evident as an increase in viscosity. Incorporating 10 % CaCl 2 as a promoter into a fresh acid solution, the hydrodynamic radius (Rh) distribution of TZXJ in varying reaction stages was analyzed using dynamic light scattering experiments. The results indicated that the promoter CaCl 2 further strengthens the network association of the TZXJ acid solution, thereby improving its thickening capability. Investigating the viscosity of TZXJ aqueous solutions with varying concentrations of CaCl 2 revealed that TZXJ exhibits notable salt-thickening effects and can withstand saturated CaCl 2 solutions. The microstructural aggregation state and morphology of TZXJ in aqueous solutions were characterized at different CaCl 2 concentrations. Dynamic light scattering results demonstrated an increase in the Rh of TZXJ solutions with CaCl 2 concentrations. In particular, the mean Rh of a 0.8 % TZXJ solution increased from 150.8 nm to 3078.93 nm. Ultraviolet spectral analysis confirmed that the absorption intensity of the TZXJ solutions increased with CaCl 2 concentration, indicating a strengthened network aggregate structure in the TZXJ solutions. Microscopic observations using environmental scanning electron microscopy and transmission electron microscopy revealed that under the influence of calcium chloride, the microstructure of TZXJ transitions from a non-associated, linear carbon chain skeleton to a dense, aggregated network structure. The findings of this study offer theoretical insights for researching polymers resistant to extreme concentrations of CaCl 2. [ABSTRACT FROM AUTHOR]

Scheme of rational designed H+/GCL-chitosan for high nitrite adsorption capacity. [Display omitted] • A feasible new strategy to enhance the nitrite adsorption of chitosan • Protonated imines are excellent anion adsorption sites • H+/GCL-chitosan has the highest nitrite adsorption capacity among chitosan adsorbents • Rapidly removing 95% of nitrite from high-concentration nitrite solution Removing hazardous nitrite from water by chitosan has many advantages such as low cost, biocompatible, and abundant availability. However, its poor adsorption capacity for nitrite hinders its practical applications. More importantly, the strategies for improving the nitrite adsorption ability of chitosan are still elusive. In this work, a systematic strategy that considers adsorption sites, surface potential, and crystallinity was proposed to enhance the nitrite adsorption of chitosan. As a demonstration, a rationally designed amorphous adsorbent (H+/GCL-chitosan) with imine adsorption sites and positive surface Zeta potential was synthesized via heterogeneous cross-linking with glutaraldehyde and then acidified in HCl solution. The obtained adsorbent exhibited a high nitrite adsorption capacity of 17.30 mg·N·g−1, far surpassing the previously-reported chitosan-based adsorbents. Theoretical calculations and mechanism studies indicated that the designed imine adsorption sites and positive surface Zeta potential are crucial for its excellent adsorption capacity. Furthermore, H+/GCL-chitosan can rapidly reach adsorption equilibrium within 3 min and maintain stable adsorption for 24 h, and the adsorbent can be regenerated effectively. To demonstrate its applications, two H+/GCL-chitosan adsorption devices achieved over 95 % of nitrite removal rate with the initial nitrite concentrations of 10 and 100 mg·N·L−1 respectively, without any pretreatment of the polluted water. These results clearly show that H+/GCL-chitosan has an excellent ability for nitrite removal. Moreover, the surface engineering strategy proposed in this work may open up new possibilities for the efficient removal of nitrite from water using chitosan-based adsorbent. [ABSTRACT FROM AUTHOR]

Marine carbon sinks act as a buffer against global warming, but raise the risk of acidification, especially in the marginal shelf seas which are rich in terrigenous carbon input. The Chinese Bohai Sea performs generally as a weak carbon source while carbon fluxes (f CO 2), pH, and aragonite saturation states (Ω arag) vary in time and space under intensive land-sea interaction. However, there are still 1) insufficient spatiotemporal resolution in existing remotely sensed retrieval of carbon flux, 2) inadequate analytic mechanism for existing empirical models, which are not suitable for case II waters in Bohai Sea, and 3) limited research on remotely sensed retrieval of acidification risk expressed as pH and Ω arag. Thus, we proposed a semi-analytical mechanism algorithm (MeSAA) to gain seawater partial pressure of CO 2 (p CO 2 sw) with hour-level GOCI imagery and seawater carbonate equilibrium equation (CO 2 SYS). With the assistance of ERA5 reanalysis data, the gained p CO 2 sw was then used to obtain f CO 2 by using the sea-air CO 2 partial pressure difference (Δ p CO 2) method. Similarly, with the assistance of remotely sensed retrieval, two indices, pH and Ω arag were also gained from CO 2 SYS to identify the acidification risk. The results showed that Bohai Sea was a weak carbon source with the positive values of f CO 2 (0.5–6 mmol C·m−2·day−1) and total emission (0.956 Tg C·yr−1). It suffered from a high acidification risk, especially in three bays with low values of Ω arag (1.15–1.3) from May to September 2011. Although photosynthetic carbon sequestration was intensive near shore, it could not consume the large amount of the rich carbon input, and resulting a monthly increase for p CO 2 sw and f CO 2 and a monthly decrease for pH and Ω arag from May to September. The distribution of p CO 2 sw was in accord with a former study, but the values were not. The local parameter adjustment of MeSAA in the Bohai Sea was analyzed for this issue, so did the effect of uncertainty analysis of mapping at different time scales (hourly and daily). Moreover, the contrast of absolute deviation and relative deviation on different time scales verified the advantage of hour-level GOCI imagery in improving assessment accuracies. This study gained a more precise change trend of p CO 2 sw, f CO 2 , pH, and Ω arag in the Bohai Sea from May to September 2011, which would be beneficial to the study of the carbon cycle in the marginal sea of the shelf under the conditions of climate change. [Display omitted] • We proposed a local MeSAA algorithm to gain p CO 2 sw in the Chinese Bohai Sea • The diurnal, daily, and monthly changes of p CO 2 sw, f CO 2 , pH, and Ω arag were gained • Bohai Sea was a carbon source with positive fCO 2 values (0.5–6 mmol C·m−2·day−1) • Three bays of Bohai Sea were in a high acidification risk with low Ω arag (1.15–1.3) • Uncertainty of mapping at different time scales(hourly and daily) were analyzed • Advantage of hour-level GOCI imagery in improving assessment accuracies was verified [ABSTRACT FROM AUTHOR]

[Display omitted] • Sulfite and acidification were proposed to improve the thermal process in watermelon juices. • Pasteurization had no significant impact on carotenoids, amino acids, and phenolics. • Pasteurization potentiated typical watermelon aromas without off-flavor formation. • Reconstituted juice showed reduced amino acids, phenolics, carotenoids, and volatile compounds. • Sulfite and acidification maintained the typical watermelon aromas in juices. The present study compared pasteurized and reconstituted (from vacuum-concentrated) watermelon juices with sulfite use (∼40 mg/L) and acidification (pH = 4.2) to fresh watermelon juices. The products were evaluated for phenolics, free amino acids, carotenoids, sugars, organic acids, and alcohols by high-performance liquid chromatography-HPLC and the volatile profile by headspace-gas chromatography/mass spectrometry (HS-GC/MS). Pasteurization had no significant impact on most of the chemical components. Furthermore, it potentiated typical watermelon aromas (E,E)-2,6-nonadienal, (Z)-3-nonen-1-ol, 4-hexen-1-ol, (E,Z)-3,6-nonadien-1-ol, 6-amino-2-methyl-2-heptanol, (E)-6-nonenal, (E)-2-nonenal, pentanal, nonanal and 1-nonanol), without off-flavor compounds formation. On the other hand, the reconstituted juice showed reduced amino acids (serine, glutamine, and tryptophan), phenolics (epicatechin gallate, myricetin, and cis -resveratrol), carotenoids (lycopene, β-carotene, and violaxanthin) and most volatile compounds. Our results showed that sulfite and acidification could maintain watermelon juice's nutritional and quality parameters after pasteurization. The vacuum concentration and reconstitution processes negatively impacted the evaluated compounds. Our findings contribute to improving thermal processes in watermelon juices for better preservation of nutrients, flavor, and bioactive compounds. [ABSTRACT FROM AUTHOR]

• Acidification can increase S fertilizer value of digestate solid fraction (DSF). • Placement of acidified DSF increased P content and uptake of ten crops. • Acidification increased root length growth of five crops out of six. • Acidification increases P fertilizer value and boost plant growth in early stages. • Therefore, placement of acidified DSF is an efficient starter phosphorus fertilizer. This study proposes employing acidified digestate solid fraction (DSF) as an effective P starter fertilizer for horticulture crops. Our investigation comprised two experiments to assess the effects of acidification and different application methods (mixed vs. acidified) of DSF on P use efficiency and root growth in horticulture crops. Acidification (7.5 % of H 2 SO 4 , ww−1) reduced the DSF pH from 9.6 to 1.6 and increased the P solubility from 14 % to 59 % of the total P. In the first experiment, we observed crop-specific responses to placement, with all ten crops exhibiting significantly higher P uptake when for acidified DSF, compared to untreated DSF mixed with the soil. Notably, root crops (carrot, onion, and fennel) and beans demonstrated the most favorable response to acidified DSF placement. The second experiment focused on six selected crops, comparing the effects of untreated DSF versus acidified DSF on root growth in rhizoboxes. Bean, pea, broccoli, carrot, and onion exhibited increased total root growth and in the soil surrounding the placement zone, due to higher P availability that boosted early-stage crop growth. Furthermore, the placement of acidified DSF also increased its sulfur fertilizer value. In conclusion, the placement of acidified DSF can make it an efficient phosphorus starter fertilizer. However, it is worth noting that the DSF has low density, and processing such as pelletization may be needed to facilitate its handling and allocation as a biobased fertilizer. Moreover, further studies are required to assess the effects on commercial yield, vegetable nutraceutical properties, and optimal application and acidification rates. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel visual omnidirectional measurement method has been proposed to measure In-situ residual fracture opening after hydraulic fracturing experiment. • Using Canny operator to correct the width of tortuous hydraulic fractures, the accuracy is improved by 33.4%. • The quantitative relationship between "acidizing effect" and "acid etching efficiency" in acid fracturing experiments is discovered. The laboratory fracturing simulation experiment is an important basis for the design and optimization of the on-site hydraulic fracturing process, and the fracture width is a key parameter for evaluating the fracturing effect. However, it is very difficult to directly obtain the in-situ residual fracture opening of the fracturing experiment. The reason is that the specimen is subjected to hydraulic action or other external forces to form a penetrating fracture surface, which displaces the original position of the fracture to be dislocated. This paper focuses on the characterization of the original residual fracture opening after the laboratory fracturing experiment and proposes a visual measurement method for the in-situ fracture width based on 3D digital image scanning technology. Hydraulic and acid fracturing studies confirmed its applicability, and residual fracture holes from the two conventional fracturing experiments were measured at the "mm" level. With the help of the Canny operator, the calculation method of zigzag residual fracture opening is revised, and the measurement accuracy of residual fracture opening is improved by 33.4%. In the meantime, by comparing and analyzing the fracture propagation characteristics of the "severe acid corrosion area" and "slight acid corrosion area" of 10%, 15%, and 20% gelling acid, the relationship between the gradient of the residual fracture opening and the "acidizing effect" and "acid etching efficiency" was obtained. This paper mainly solves the problem that in-situ residual fracture opening cannot be obtained in fracturing experiments and can provide parameter guidance for quantitative evaluation of fracturing effects and estimation of fracturing productivity. [ABSTRACT FROM AUTHOR]

Fermentation of cereal grains may hydrolyse myo -inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP 6) and increase concentration of lower order inositol phosphates (InsP) in vitro , thereby increasing nutrient digestibility in diets of swine and poultry. Effects of chemical acidification or fermentation with the lactic acid-producing bacteria Limosilactobacillus reuteri or Weisella cibaria of high β-glucan hull-less barley grain on pH, organic acid concentration, InsP 6 hydrolysis and lower order InsP formation were assessed in vitro. In 3 batches, ground barley grain was treated in four forms balanced for water content: 1) unfermented barley (Control); 2) chemically acidified barley with lactic acid and acetic acid (0.019 L/kg barley grain at a ratio of 4:1 (volume/volume)) (ACD); 3) barley fermented with L. reuteri TMW 1.656 (Fermented with L. reuteri); and 4) barley fermented with W. cibaria 10 M FUA3120 (Fermented with W. cibaria). For 24 h in an incubator, ACD and Fermented with L. reuteri were incubated at 37 °C and Fermented with W. cibaria at 30 °C. Barley inositol phosphate 6 -phosphorus (InsP 6 -P) was 68%, 64% and 41% lower, respectively, for ACD, Fermented with L. reuteri or Fermented with W. cibaria than Control. Barley grain pH after 24 h, concentration of InsP 6 -P, inositol phosphate 5 -phosphorus (InsP 5 -P), inositol phosphate 4 -phosphorus (InsP 4 -P) and sum inositol phosphate 6–2 -phosphorus (InsP 6–2 -P) were lower (P < 0.05) for ACD and Fermented barley grain than Control and Fermented with L. reuteri than W. cibaria. Acetate, lactate, inositol phosphate 3 -phosphorus (InsP 3 -P) and inositol phosphate 2 -phosphorus (InsP 2 -P) concentration was greater (P < 0.05) for ACD and Fermented barley grain than Control. Lactate and InsP 2 -P concentration were greater (P < 0.01) for Fermented with L. reuteri than W. cibaria. Total P release, cumulative P release of InsP 6 -P, InsP 5 -P, InsP 4 -P and InsP 3 -P were greater (P < 0.01) for Fermented with L. reuteri than W. cibaria. In conclusion, lower pH in ACD and Fermentation indicated that acidification is important for InsP 6 hydrolysis via intrinsic phytase activation in barley grain in vitro. Between strains, fermentation with L. reuteri maximised acidification, lactate concentration and degradation of InsP 6 -P, InsP 5 -P, InsP 4 -P in barley grain. • Acidification activates intrinsic phytase to hydrolyse inositol phosphate 6. • Fermentation maximised inositol phosphate degradation. • Fermentation increases phosphorus availability. [ABSTRACT FROM AUTHOR]

The long-term field experiments at Rothamsted in south-east England (UK) are an important resource that has been used extensively to study the effects of land management, atmospheric pollution and climate change on soil fertility and the sustainability of crop yields. However, for these and other long-term experiments around the world to remain useful, changes are sometimes needed. These changes may be required to ensure that the experiment is not compromised by e.g. acidification or weeds, but often they are needed to ensure that the experiment remains relevant to current agricultural practice, e.g. the introduction of new cultivars and the judicious use of pesticides. However, changes should not be made just for the sake of change or to investigate aspects of management that could be better resolved in a short-term experiment. Rather, modifications should only be made after carefully considered discussion, involving scientists from different disciplines. It must be remembered however that there are limitations to what can be achieved in one experiment. In this paper we give examples of why certain changes were made to the Rothamsted experiments and what the results of those changes have been. We also highlight the value of archiving crop and soil samples for future studies. • The management of Rothamsted's long-term experiments (LTEs) is discussed. • The effects of that management on soil fertility and crop yields are considered. • The need for changes to LTEs to ensure their continued relevance is emphasised. • Reasons for changes to Rothamsted's LTEs and the results of those changes are given. • The value of archived soil and crop samples is highlighted. [ABSTRACT FROM AUTHOR]

• Acidification is induced in the gingival sulcus of mechanically forced tooth. • Buffering the gingival acidity ameliorates orthodontic mechanical allodynia. • ASIC3 is involved in the mechanical allodynia induced by orthodontic force. • Tooth movement causes ASIC3 phosphorylation in the periodontal tissue. Tooth movements associated with orthodontic treatment often cause tooth pain. However, the detailed mechanism remains unclear. Here, we examined the involvement of periodontal acidification caused by tooth movement in mechanical tooth pain hypersensitivity. Elastics were inserted between the first and second molars to move the teeth in Sprague-Dawley rats. Mechanical head-withdrawal reflex threshold to first molar stimulation and the pH of the gingival sulcus around the tooth were measured. The expression of acid-sensing ion channel 3 (ASIC3) in trigeminal ganglion neurons and phosphorylation of ASIC3 in the periodontal tissue were analyzed. The mechanical head-withdrawal reflex threshold to first molar stimulation and pH in the gingival sulcus decreased on day 1 after the elastic insertion. These decreases recovered to the sham level by buffering periodontal acidification. Periodontal inhibition of ASIC3 channel activity reversed the decreased mechanical head-withdrawal reflex threshold to first molar stimulation. On day 1 after elastic insertion, the tooth movement did not change the number of ASIC3 immunoreactive trigeminal ganglion neurons innervating the periodontal tissue but increased phosphorylated-ASIC3 levels in the periodontal tissue. Periodontal acidification induced by tooth movement causes phosphorylation of ASIC3, resulting in mechanical pain hypersensitivity in mechanically forced tooth. [ABSTRACT FROM AUTHOR]

In this study, the effect of biochar addition derived from a downdraft fixed-bed gasifier on the performances of dry anaerobic digestion of the Organic Fraction of Municipal Solid Waste (OFMSW) was investigated at a high organic load of (1) the source segregated OFMSW (16 and 26% TS) and (2) the source segregated OFMSW replaced with 15% garden waste (22.2% TS). Adding biochar effectively enhanced the rate and yield of biomethane (up to 36.6%), controlled acidification, and shortened lag phase in both feedstocks at high organic loads up to 136.9 gVS/L. Execution of dry anaerobic digestion for source-separated OFMSW without acidification can only be achieved by more than 30 g/L biochar dosage, which is better to run in a semi-solid state (16% TS). However, the synergistic effects at higher biochar doses were not palpable. OFMSW with a higher C/N ratio yielded more limited benefits, as inhibitory volatile fatty acids were further controlled in the early days. This study could promise the integration of gasification and dry anaerobic digestion to enhance the biogas production efficiency at high organic loads, although more researches should be done under continuous conditions. [ABSTRACT FROM AUTHOR]

• Acidification of La doped C 3 N 4 photocatalyst was obtained by a simple method. • The doping of La and acidification increases the specific surface area. • Reduction band gap and recombination efficiency of electron-hole pairs. In this study, the photocatalytic performance of g-C 3 N 4 is improved by doping lanthanum and hydrochloric acid acidification. The prepared samples were characterized by XRD, XPS, ICP, SEM, BET and UV vis DRS. From the SEM and BET results, it can be seen that both doping lanthanum and hydrochloric acid acidification can affect the microstructure of the sample to a certain extent, resulting in a larger specific surface area of the sample. According to UV–vis DRS, it can be determined that the doping of lanthanum and hydrochloric acid acidification have to some extent reduces the band gap of the sample, reduces the recombination rate of electron-hole pair in the sample, makes the photocatalytic process more likely to occur, and improves the photocatalytic performance. Compared with g-C 3 N 4 , g-C 3 N 4 /La samples have stronger photocatalytic performance, with a 2-hour photocatalytic degradation rate of 95.54 % for tetracycline in g-C 3 N 4 /La-400. Based on this, acidification of the sample can further improve its performance, and the 2-hour photocatalytic degradation rate of tetracycline in g-C 3 N 4 /La-HCl4 can reach 99.40 %. This study indicates that the doping of lanthanum and hydrochloric acid acidification treatment can improve the photocatalytic performance of g-C 3 N 4. g-C 3 N 4 /La-HCl4 has certain application prospects in the degradation of tetracycline and other macromolecular organic compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

• Extent of acidification affected the reversibility of solubilized calcium. • Re-neutralization altered fat-protein interactions in feed. • Feed viscosity was primarily affected by final pH. • pH alterations led to distinct destabilization behavior among the feeds. Cheese feed is used as spray-dryer feed in cheese powder production, where there is growing consumer demand to eliminate calcium-chelating salts (ES). To develop ES-free feed production processes, it is essential to investigate the relationship between pH, structural changes, and mineral solubilization. This study investigated the influence of acidification and pH re-neutralization on calcium equilibria and stability of ES-free model cheese feeds. The goal was to increase protein availability by solubilizing colloidal calcium phosphate (CCP) and to assess whether CCP solubilization is reversible upon re-neutralization. The extent of acidification (to pH 4.2 or pH 4.7) significantly affected the irreversibility of calcium solubilization upon re-neutralization. Moreover, re-neutralization treatment seemed to induce changes in protein-fat interactions. Feed viscosity was mainly influenced by the final pH, rather than the re-neutralization history. These results offer new insights into the complex interplay of pH, structural modifications, mineral solubilization, and stability in cheese feed production. [ABSTRACT FROM AUTHOR]

To date, little is known about the impact of super-eruptions on ocean biogeochemistry. Using boron isotopes ratios measured on planktonic foraminifera in the marine sediment core BAR94–25, we provide a high-resolution pH record in the Andaman Sea (North of Sumatra), spanning Marine Isotopic Stage 5 to 3. This transition encompasses the super-eruption of the Toba volcano, 74,000 years ago, making it possible to decipher the potential impact of the super-eruption emissions on the ocean pH for the first time. Our results show that inferred foraminiferal pH values generally follow those predicted by glacial-interglacial CO 2 variations. However, several abrupt pH drops coincide with Toba ash deposition. This suggests the occurrence of acidification events possibly related to Toba volcanic sulphur emission episodes. These pH drops are followed by anomalous pH increases, possibly relating to localised increases in seawater alkalinity following the alteration of large ash deposits on land. • High resolution reconstruction of surface seawater pH using boron isotopes. • Toba volcano impacted the surface seawater chemistry of the Andaman Sea. • Episodes of surface seawater acidification were observed in the Andaman Sea during volcanic avtivity of Toba volcano. • Following the volcanic eruption, an increase of surface seawater pH happened due to alkalinisation. [ABSTRACT FROM AUTHOR]

Extracellular acidification is a major component of tissue inflammation, including airway inflammation in asthmatics. However, its physiological/pathophysiological significance in bronchial function is not fully understood. Currently, the functional role of extracellular acidification on bronchial contraction was explored. Left main bronchi were isolated from male BALB/c mice. Epithelium-removed tissues were exposed to acidic pH under submaximal contraction induced by 10−5 M acetylcholine in the presence or absence of a COX inhibitor indomethacin (10−6 M). Effects of AH6809 (10−6 M, an EP 2 receptor antagonist), BW A868C (10−7 M, a DP receptor antagonist) and CAY10441 (3×10−6 M, an IP receptor antagonist) on the acidification-induced change in tension were determined. The release of prostaglandin E 2 (PGE 2) from epithelium-denuded tissues in response to acidic pH was assessed using an ELISA. In the bronchi stimulated with acetylcholine, change in the extracellular pH from 7.4 to 6.8 caused a transient augmentation of contraction followed by a sustained relaxing response. The latter inhibitory response was abolished by indomethacin and AH6809 but not by BW A868C or CAY10441. Both indomethacin and AH6809 significantly increased potency and efficacy of acetylcholine at pH 6.8. Stimulation with low pH caused an increase in PGE 2 release from epithelium-denuded bronchi. Interestingly, the acidic pH-induced bronchial relaxation was significantly reduced in a murine asthma model that had a bronchial hyperresponsiveness to acetylcholine. Taken together, extracellular acidification could inhibit the bronchial contraction via autocrine activation of EP 2 receptors. The diminished acidic pH-mediated inhibition of bronchial tone may contribute to excessive bronchoconstriction in inflamed airways such as asthma. • Extracellular acidification caused a transient augmentation of contraction followed by a sustained relaxing response. • The latter relaxing response was abolished by an EP 2 receptor antagonist AH6809. • Extracellular acidification caused an increase in PGE 2 release from epithelium-denuded bronchi. • The relaxing response induced by extracellular acidification was significantly reduced in a murine asthma model. [ABSTRACT FROM AUTHOR]

• Negative relations exist between BET-specific surface area and coal floatability. • Pore at 1–20 μm diameter range is influential to the floatability of coal. • Dissolving and re-sedimentation of mineral components altered pore characteristics. • High porosity and minerals inside pores contribute to the low floatability of coal. This paper investigated the relationship between coal floatability and pore characteristics from the perspective of froth flotation. Three types of coal samples with different ash contents were pretreated with HCl and acetic acid solutions to alter the pore features. The X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were conducted to specify the reactions that happened in acidification. The batch flotation and contact angle measurements were conducted to evaluate the floatability of the coal samples. The liquid nitrogen adsorption and mercury intrusion porosimetry (MIP) measurements were applied to measure the pore characteristics of the coal. The acidification treatment partially dissolved mineral components and organic functional groups on the coal surface but did not change the types of the major functional groups. The sedimentation of liberated fine minerals on coal pores caused the decrease in pore volume. The BET specific surface area of the three coal samples after acidification was found to have consistent negative relations with the flotation recovery and combustible recovery rate. This indicated the adverse impact of porosity in coal flotation. The floatability of coal is mainly influenced by the pores at the size fraction of 1–20 μm by pore volume. The nano-scale size pore and fine mineral inside the micron pore increased the water-wettability and resulted in the low floatability of coal. [ABSTRACT FROM AUTHOR]

Targeted removal of three key refractory toxic organic compounds (TOMs) in 2-butenal manufacturing wastewater (2-BMW) is critical for enhancing pre-treatment by hydrolysis acidification (HA). We investigated the pre-treatment of 2-BMW with HA, coupled with ozonation in this study. Our results indicated that the removal rate of these key TOMs and the detoxification rate reached almost 100% and 46.3%, respectively, by ozonation under only 0.099 mg O 3 /mg chemical oxygen demand (COD). The organic load rate (OLR) reached 10.25 ± 0.43 kg COD/m3·d, and the acidification degree (AD) and detoxification efficiency reached 56.0% and 98.3%, respectively, with enhancements of 35.1% and 55.2%, respectively, compared with HA alone. The removal rate of the three key TOMs was improved by > 75%. The degradation pathways of these key TOMs were ring cleavage and ester formation by ozonation, followed by fermentation and acid production by HA. Ultimately, the synergistic role of ozonation and HA was revealed. The preferential cleavage of these key TOMs by ozonation was achieved because of their high electron cloud density and multiple reaction sites, which generated more fermentation-friendly products. The fermentation and acid production reactions may be directly involved in these products. Functional bacteria and key metabolic pathways were also enhanced by ozonation. [Display omitted] • Pre-treatment of 2-BMW was enhanced by HA coupled with ozonation. • Targeted cleavage of key TOMs by pre-ozonation was achieved. • Ring-cleavage, esters formation, and fermentation were main pathways. • Fermentative bacteria and metabolisms were enriched. • Synergistic role of ozonation and HA was revealed. [ABSTRACT FROM AUTHOR]

The valorization of sheep and goat cheese whey are important from economic, social and environmental perspectives. However, their low microbiological and physical stabilities are major challenges, especially for artisanal productions. In this study, the effectiveness of nisin addition, bioprotective culture (Lacticaseibacillus casei) inoculation and direct acidification (pH 2.5–4.5) was evaluated to improve the stability of pasteurized (75 °C/5 min) sheep and goat cheese whey. All strategies were effective in controlling the native microbial population, with minimal or no change in the pH or acidity during 28 days/7 °C, whereas samples only pasteurized reached counts of up to 8 log CFU/mL. Phase separation occurred in all samples, but at different rates and intensities. Acidification at pH 3.5 and 4.5 resulted in higher creaming rates (up to 30%), even without change in fat globule size, and sedimentation (up to 6%), due to protein particle agglomeration - that increased D [3,2] values by up to 27% and reduced the specific surface area by around 20%. Conversely, acidification at pH 2.5 or the addition of nisin or L. casei resulted in samples with smaller particle size and better stability to creaming and sedimentation. The results indicated that nisin addition or L. casei inoculation are possible strategies to improve the shelf life of sheep and goat pasteurized whey, which can be used even by artisanal producers, and thus contributing for their valorization. • We develop strategies for sheep (SCW) and goat whey (GCW) valorization. • Nisin, L. casei and direct acidification (pH 2.5–4.5) inhibited SCW/GCW contaminants. • Acidification increased particle size and caused cream separation and sedimentation. • Nisin and L. casei were the best strategies to stabilize SCW and GCW. • The developed solutions can be directly applied in artisanal production. [ABSTRACT FROM AUTHOR]