Exogenous melatonin delays leaves senescence and enhances saline and alkaline stress tolerance in grape seedlings

Saline and alkaline stress is one of the major abiotic stresses facing agricultural production, which severely inhibits the growth and yield of plant. The application of plant growth regulators can effectively prevent crop yield reduction caused by saline and alkaline stress. Exogenous melatonin (MT) can act as a signaling molecule involved in the regulation of a variety of physiological processes in plants, has been found to play a key role in enhancing the improvement of plant tolerance to abiotic stresses. However, the effects of exogenous MT on saline and alkaline tolerance of table grape seedlings and its mechanism have not been clarified. The aim of this study was to investigate the role of exogenous MT on morphological and physiological growth of table grape seedlings (Vitis vinifera L.) under saline and alkaline stress. The results showed that saline and alkaline stress resulted in yellowing and wilting of grape leaves and a decrease in chlorophyll content, whereas the application of exogenous MT alleviated the degradation of chlorophyll in grape seedling leaves caused by saline and alkaline stress and promoted the accumulation of soluble sugars and proline content. In addition, exogenous MT increased the activity of antioxidant enzymes, which resulted in the scavenging of reactive oxygen species (ROS) generated by saline and alkaline stress. In conclusion, exogenous MT was involved in the tolerance of grape seedlings to saline and alkaline stress, and enhanced the saline and alkaline resistance of grape seedlings to promote the growth and development of the grape industry in saline and alkaline areas.

Combined dilute alkali and milling process enhances the functionality and gut microbiota fermentability of insoluble corn fiber

In this study, we developed a process combining dilute alkali (NaOH or NaHCO3) and physical (disk milling and/or ball milling) treatments to improve the functionality and fermentability of corn fiber. The results showed that combining chemical with physical processes greatly improved the functionality and fermentability of corn fiber. Corn fiber treated with NaOH followed by disk milling (NaOH-DM-CF) had the highest water retention (19.5 g/g), water swelling (38.8 mL/g), and oil holding (15.5 g/g) capacities. Moreover, NaOH-DM-CF produced the largest amount (42.9 mM) of short-chain fatty acid (SCFA) during the 24-hr in vitro fermentation using porcine fecal inoculum. In addition, in vitro fermentation of NaOH-DM-CF led to a targeted microbial shifting to Prevotella (genus level), aligning with a higher fraction of propionic acid. The outstanding functionality and fermentability of NaOH-DM-CF were attributed to its thin and loose structure, decreased ester linkages and acetyl groups, and enriched structural carbohydrate exposure.

Structural and rheological properties of diluted alkali soluble pectin from apple and carrot

Pectin, a complex polysaccharide found in plant cell walls, plays a crucial role in various industries due to its functional properties. The diluted alkali-soluble pectin (DASP) fractions that result from the stepwise extraction of apples and carrots were studied to evaluate their structural and rheological properties. Homogalacturonan and rhamnogalacturonan I, in different proportions, were the main pectin domains that composed DASP from both materials. Atomic force microscopy revealed that the molecules of apple DASP were longer and more branched. A persistence length greater than 40 nm indicated that the pectin molecules deposited on mica behaved as stiff molecules. The weight-averaged molar mass was similar for both samples. Intrinsic viscosity values of 194.91 mL·g-1 and 186.79 mL·g-1 were obtained for apple and carrot DASP, respectively. Rheological measurements showed greater structural strength for apple-extracted pectin, whereas carrot pectin was characterized by a higher linear viscoelasticity limit. This comparison showed that the pectin fractions extracted by diluted alkali are structurally different and have different rheological properties depending on their botanical origin. The acquired insights can enhance the customized use of pectin residue and support further investigations in industries relying on pectin applications.

An alkali-extracted neutral heteropolysaccharide from Phellinus nigricans used as an immunopotentiator in immunosuppressed mice by activating macrophages

A neutral heteropolysaccharide (PNANb) was isolated with alkali (0.1 M NaOH) from mycelia of Phellinus nigricans, and the structure, immunostimulating activity and some of the underlying molecular mechanisms of action of PNANb were explored in the current study. PNANb (14.95 kDa) predominantly consisted of Gal, Glc, and Man with minor Fuc. GC-MS and NMR analyses indicated that the backbone of PNANb was mainly composed of 6-α-Galp, 2,6-α-Galp with minor 3,6-β-Glcp, which was substituted with complex side chains at C-2 of 2,6-α-Galp and C-3 of 3,6-β-Glcp. Notably, PNANb (50 or 100 mg/kg) possessed immunoprotective effects in cyclophosphamide (Cy)-induced immunosuppressed C57BL/6 mice, which was supported by evidence including the enhancement of spleen and thymus indices, levels of serum immunoglobulins (IgG, IgM) and cytokines (IFN-γ, IL-2, IL-4, IL-10), and macrophage activity. However, the immunostimulation effects of PNANb were decreased when macrophages were depleted, underscoring the essential role of macrophages in the beneficial effects of PNANb in Cy-induced immunosuppressed mice. Further investigations in vitro indicated that PNANb activated macrophages through MAPK/NF-κB signaling pathways mediated by Toll-like receptor 4. Therefore, PNANb can serve as a prospective immunopotentiator in immunosuppression.

Functional activity of endophytic bacteria G9H01 with high salt tolerance and anti-Magnaporthe oryzae that isolated from saline-alkali-tolerant rice

It holds significant practical importance to screen and investigate endophytic bacteria with salt-tolerant activity in rice for the development of relevant microbial agents. A total of 179 strains of endophytic bacteria were isolated from 24 samples of salt-tolerant rice seeds, with almost 95 % of these bacteria exhibiting tolerance to a salt content of 2 % (0.34 mol/L). Following the screening process, a bacterium named G9H01 was identified, which demonstrated a salt tolerance of up to 15 % (2.57 mol/L) and resistance to Magnaporthe oryzae, the causal agent of rice blast disease. Phylogenetic analysis confirmed G9H01 as a strain of Bacillus paralicheniformis. The complete genome of G9H01 was sequenced and assembled, revealing a considerable number of genes encoding proteins associated with salt tolerance. Further analysis indicated that G9H01 may alleviate salt stress in a high-salt environment through various mechanisms. These mechanisms include the utilization of proteins such as K+ transporters, antiporters, and Na+/H+ antiporters, which are involved in K+ absorption and Na+ excretion. G9H01 also demonstrated the ability to uptake and accumulate betaine, as well as secrete extracellular polysaccharides. Collectively, these findings suggest that Bacillus paralicheniformis G9H01 has potential as a biocontrol agent, capable of promoting rice growth under saline-alkali-tolerant conditions.

Alkali and alkaline earth elements in follicular fluid and the likelihood of diminished ovarian reserve in reproductive-aged women: a case‒control study

BACKGROUND

Imbalances in alkali elements (AEs) and alkaline earth elements (AEEs) cause reproductive disorders. However, it remains unclear whether AEs/AEEs in follicular fluid have a relationship with the serious reproductive disorder known as diminished ovarian reserve (DOR).

METHODS

A nested case‒control study was carried out in China. Follicular fluid samples from 154 DOR patients and 154 controls were collected and assessed for nine AEs/AEE levels. Both the mixed and single effects of the elements on DOR were estimated with a Bayesian kernel machine (BKMR) and logistic regressions.

RESULTS

The DOR group had higher median concentrations of Li, Na, and K in follicular fluid (all P values < 0.05). The logistic regression showed that compared with their lowest tertile, the high tertiles of K [OR:2.45 (1.67-4.43)], Li [OR: 1.89 (1.06-3.42)], and Cs [OR: 1.97 (1.10-3.54)] were significantly associated with the odds of DOR. The BKMR model reported that the DOR likelihood increased linearly across the 25th through 75th percentiles of the nine-AE/AEE mixture, while the AE group contributed more to the overall effect.

CONCLUSION

This study revealed an association in which the likelihood of DOR increased with higher overall concentrations of AE/AEEs in follicular fluid. Among the nine detected elements, K, Li, and Cs exhibited significant individual associations with DOR. We provide new clues for the environmental factors on female fertility decline.

TRIAL REGISTRATION

Retrospectively registered.

Short-term high-temperature pretreated compost increases its application value by altering key bacteria phenotypes

Short-term high-temperature pretreatment can effectively shorten the maturity period of organic waste composting and improve the fertilizer efficiency and humification degree of products. To investigate the effect and mechanism of the end products on the saline-alkali soil improvement and plant growth, the short-term high-temperature pretreatment composting (SHC) and traditional composting (STC) were separately blended with saline-alkali soil in a ratio of 0-40 % to establish a soil-fertilizer blended matrix for cultivating Lolium perenne L. The pot experiments combined with principal component analysis showed Lolium perenne L. planted in 20 % SHC-blended saline-alkali soil had the best growth effect, and its biomass, chlorophyll content, and plant height were 109-113 % higher than STC. The soil physicochemical property analysis showed that SHC and STC increased the soil nutrient content, humification degree, and enzyme activity at any blending ratio. The microbial analysis showed that 20 % SHC in the saline-alkali soil stimulated the growth of functional microorganisms and the addition of SHC promoted the sulfur cycle, nitrogen fixation, and carbon metabolism in the soil-plant system. The correlation analysis showed that pH; nutrient contents; and urease, catalase, sucrase, and phosphatase activities in the saline-alkali soil were significantly correlated with plant growth indexes (p < 0.05). Georgenia and norank_f__Fodinicurvataceae had a stronger correlation with four types of enzyme activities (p < 0.01). SHC improved the saline-alkali soil and promoted plant growth by adjusting soil pH, increasing soil nutrients, and influencing soil enzyme activity and dominant flora. This study provides a theoretical basis for applying SHC products in soil improvement.

Soil amendments reduce CH4 and CO2 but increase N2O and NH3 emissions in saline-alkali paddy fields

Limited research has been conducted on ammonia (NH3) volatilization and greenhouse gases (GHGs) emissions in saline-alkali paddy fields, along with complex interaction involving various genes (16sRNA, amoA, narG, nirK, nosZ, and nifH). This study employed mesocosm-scale experiment to investigate NH3 volatilization and GHGs emissions, focusing on bacterial communities and genic abundance, in saline-alkali paddy fields with desulfurized gypsum (DG) and organic fertilizer (OF) amendments. Compared to the control (CK) treatment, DG and OF treatments reduced methane (CH4) and carbon dioxide (CO2) emissions by 78.05 % and 26.18 %, and 65.84 % and 11.62 %, respectively. However, these treatments increased NH3 volatilization by 26.26 % and 45.23 %, and nitrous oxide (N2O) emission by 41.00 % and 12.31 %. Notably, NH3 volatilization primarily stemmed from ammonia nitrogen (NH4+-N), rather than total nitrogen (TN) in soil and water. N2O was mainly produced from nitrate nitrogen (NO3--N) in soil and water, as well as NH4+-N in water. The increase in NH3 volatilization and N2O emission in DG and OF treatments, was attributed to the reduced competition among bacterial communities, rather than the increased bacterial activity and genic copies. These findings offer valuable insights for managing nutrient loss and gaseous emissions in saline-alkali paddy fields.

Remediation of soda-saline-alkali soil through soil amendments: Microbially mediated carbon and nitrogen cycles and remediation mechanisms

Due to the high salt content and pH value, the structure of saline-sodic soil was deteriorated, resulting in decreased soil fertility and inhibited soil element cycling. This, in turn, caused significant negative impacts on crop growth, posing a major challenge to global agriculture and food security. Despite numerous studies aimed at reducing the loss of plant productivity in saline-sodic soils, the knowledge regarding shifts in soil microbial communities and carbon/nitrogen cycling during saline-sodic soil improvement remains incomplete. Consequently, we developed a composite soil amendment to explore its potential to alleviate salt stress and enhance soil quality. Our findings demonstrated that the application of this composite soil amendment effectively enhanced microbial salinity resistance, promotes soil carbon fixation and nitrogen cycling, thereby reducing HCO3- concentration and greenhouse gas emissions while improving physicochemical properties and enzyme activity in the soil. Additionally, the presence of CaSO4 contributed to a decrease in water-soluble Na+ content, resulting in reduced soil ESP and pH by 14.64 % and 7.42, respectively. Our research presents an innovative approach to rehabilitate saline-sodic soil and promote ecological restoration through the perspective of elements cycles.

The Response of Hormones, Reactive Oxygen Species and Nitric Oxide in the Polyethylene-Glycol-Promoted, Salt-Alkali-Stress-Induced Embryo Germination of Sorbus pohuashanensis

Polyethylene glycol can abrogate plant seed dormancy and alleviate salt-alkali stress damage to plants, but its role in embryonic dormancy abrogation and germination in Sorbus pohuashanensis is not yet clear. The mechanism by which polyethylene glycol promotes the release of embryonic dormancy may be related to the synthesis and metabolism of endogenous hormones, reactive oxygen species and reactive nitrogen. In this article, germination in indoor culture dishes was used, and the most suitable conditions for treating S. pohuashanensis embryos, with polyethylene glycol (PEG) and sodium carbonate (Na2CO3), were selected. Germination was observed and recorded, and related physiological indicators such as endogenous hormones, reactive oxygen species and reactive nitrogen were measured and analyzed to elucidate the mechanism of polyethylene glycol in alleviating salt-alkali stress in S. pohuashanensis embryos. The results showed that soaking seeds in 5% PEG for 5 days is the best condition to promote germination, which can increase the germination rate of embryos under salt-alkali stress by 1-2 times and improve indicators such as germination speed and the germination index. Polyethylene glycol led to an increase in gibberellin (GA), indole-3-acetic acid (IAA), ethylene (ETH), cytokinin (CTK), nitric oxide (NO), soluble protein and soluble sugar in the embryos under salt-alkali stress; increased activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), nitrate reductase (NR) and nitric oxide synthase (NOS) in the embryos; a reduction in the accumulation of abscisic acid (ABA), hydrogen peroxide (H2O2) and malondialdehyde (MDA). Therefore, it is suggested that the inhibitory effect of polyethylene glycol on the salt-alkali-stress-induced germination of S. pohuashanensis embryos is closely related to the response of endogenous hormones, reactive oxygen species and nitric oxide signalling.

Elucidating the role of exogenous melatonin in mitigating alkaline stress in soybeans across different growth stages: a transcriptomic and metabolomic approach

BACKGROUND

Soybean (Glycine max), a vital grain and oilseed crop, serves as a primary source of plant protein and oil. Soil salinization poses a significant threat to soybean planting, highlighting the urgency to improve soybean resilience and adaptability to saline stress. Melatonin, recently identified as a key plant growth regulator, plays crucial roles in plant growth, development, and responses to environmental stress. However, the potential of melatonin to mitigate alkali stress in soybeans and the underlying mechanisms remain unclear.

RESULTS

This study investigated the effects of exogenous melatonin on the soybean cultivar Zhonghuang 13 under alkaline stress. We employed physiological, biochemical, transcriptomic, and metabolomic analyses throughout both vegetative and pod-filling growth stages. Our findings demonstrate that melatonin significantly counteracts the detrimental effects of alkaline stress on soybean plants, promoting plant growth, photosynthesis, and antioxidant capacity. Transcriptomic analysis during both growth stages under alkaline stress, with and without melatonin treatment, identified 2,834 and 549 differentially expressed genes, respectively. These genes may play a vital role in regulating plant adaptation to abiotic stress. Notably, analysis of phytohormone biosynthesis pathways revealed altered expression of key genes, particularly in the ARF (auxin response factor), AUX/IAA (auxin/indole-3-acetic acid), and GH3 (Gretchen Hagen 3) families, during the early stress response. Metabolomic analysis during the pod-filling stage identified highly expressed metabolites responding to melatonin application, such as uteolin-7-O-(2''-O-rhamnosyl)rutinoside and Hederagenin-3-O-glucuronide-28-O-glucosyl(1,2)glucoside, which helped alleviate the damage caused by alkali stress. Furthermore, we identified 183 differentially expressed transcription factors, potentially playing a critical role in regulating plant adaptation to abiotic stress. Among these, the gene SoyZH13_04G073701 is particularly noteworthy as it regulates the key differentially expressed metabolite, the terpene metabolite Hederagenin-3-O-glucuronide-28-O-glucosyl(1,2)glucoside. WGCNA analysis identified this gene (SoyZH13_04G073701) as a hub gene, positively regulating the crucial differentially expressed metabolite of terpenoids, Hederagenin-3-O-glucuronide-28-O-glucosyl(1,2)glucoside. Our findings provide novel insights into how exogenous melatonin alleviates alkali stress in soybeans at different reproductive stages.

CONCLUSIONS

Integrating transcriptomic and metabolomic approaches, our study elucidates the mechanisms by which exogenous melatonin ameliorates the inhibitory effects of alkaline stress on soybean growth and development. This occurs through modulation of biosynthesis pathways for key compounds, including terpenes, flavonoids, and phenolics. Our findings provide initial mechanistic insights into how melatonin mitigates alkaline stress in soybeans, offering a foundation for molecular breeding strategies to enhance salt-alkali tolerance in this crop.

Preventive Pharmacological Therapy and Risk of Recurrent Urinary Stone Disease

BACKGROUND

Urinary stone disease is a prevalent condition associated with a high recurrence risk. Preventive pharmacological therapy has been proposed to reduce recurrent stone episodes. However, limited evidence exists regarding its effectiveness, contributing to its underutilization by physicians. This study aimed to evaluate the association between preventive pharmacological therapy (thiazide diuretics, alkali therapy, and uric acid-lowering medications) and clinically significant urinary stone disease recurrence.

METHODS

Using data from the Veterans Health Administration, adults with an index episode of urinary stone disease from 2012 through 2019 and at least one urinary abnormality (hypercalciuria, hypocitraturia, or hyperuricosuria) on 24-hour urine collection were included. The primary outcome was a composite variable representing recurrent stone events that resulted in emergency department visits, hospitalizations, or surgery for urinary stone disease. Cox proportional hazards regression was performed to estimate the association between preventive pharmacological therapy use and recurrent urinary stone disease while adjusting for relevant baseline patient characteristics.

RESULTS

Among the cohort of patients with urinary abnormalities ( n =5637), treatment with preventive pharmacological therapy was associated with a significant 19% lower risk of recurrent urinary stone disease during the 12-36-month period after the initial urine collection (hazard ratio, 0.81; 95% confidence interval, 0.65 to 1.00; P = 0.0496). However, the effectiveness of preventive pharmacological therapy diminished over longer follow-up periods (12-48 and 12-60 months after the urine collection) and did not reach statistical significance. When examining specific urinary abnormalities, only alkali therapy for hypocitraturia was associated with a significant 26% lower recurrence risk within the 12-36-month timeframe (hazard ratio, 0.74; 95% confidence interval, 0.56 to 0.97; P = 0.03).

CONCLUSIONS

When considering all urinary abnormalities together, this study demonstrates that the use of preventive pharmacological therapy is associated with a lower risk of clinically significant recurrent episodes of urinary stone disease in the 12-36 month timeframe after urine collection, although only the association with the use of alkali therapy for hypocitraturia was significant when individual abnormalities were examined.

Potassium transporter OsHAK17 may contribute to saline-alkaline tolerant mechanisms in rice (Oryza sativa)

Rice production is seriously affected by saline-alkaline stress worldwide. To elucidate the saline-alkaline tolerance mechanisms in a novel tolerant rice variety, Shwe Nang Gyi (SNG), we investigated ion accumulation in SNG and Koshihikari (KSH), which is a saline-alkaline sensitive rice variety, and the candidates for saline-alkaline inducible genes in SNG using RNA-seq. SNG had superior ion accumulation capacity, such as K and Zn, compared to KSH. In contrast, SNG accumulated the same level of Na content in its leaf blades as KSH despite the higher dry weight of the SNG leaf blades. We further found that the expression of numerous genes, including several K+ transporter/high-affinity K+ transporter/K+ uptake protein/K+ transporter (HAK/KUP/KT) family members, were upregulated in SNG, and that OsHAK17 and OsHAK21 expression levels in the roots were significantly higher in SNG than in KSH. Moreover, yeast complementation analysis revealed that OsHAK17 was involved in K+ uptake under high-Na conditions. These results suggested that SNG has an effective K+ acquisition system supported by OsHAK17 functioning in saline-alkaline environments.

Surface expression of carbonic anhydrase on E. coli as a sustainable approach for enzymatic CO2 capture

The utilisation of carbonic anhydrase (CA) in CO2 sequestration is becoming prominent as an efficient, environment friendly and rapid catalyst for capturing CO2 from industrial emissions. However, the application of CA enzyme in soluble form is constrained due to its poor stability in operational conditions of CO2 capture and also production cost of the enzyme. Addressing these limitations, the present study focuses on the surface display of CA from Bacillus halodurans (BhCA) on E coli aiming to contribute to the cost-effectiveness of carbon capture through CA technology. This involved the fusion of the BhCA-encoding gene with the adhesion molecule involved in diffuse adherence (AIDA-I) autotransporter, resulting in the efficient display of BhCA (595 ± 60 U/gram dry cell weight). Verification of the surface display of BhCA was accomplished by conjugating with FITC labelled anti-his antibody followed by fluorescence-activated cell sorting (FACS) and cellular fractionation in conjunction with zymography. Biochemical characterisation of whole-cell biocatalyst revealed a noteworthy enhancement in thermostability, improvement in the thermostability with T1/2 of 90 ± 1.52 minutes at 50 ˚C, 36 ± 2.51 minutes at 60 ˚C and18 ± 1.52 minutes at 80˚C. Surface displayed BhCA displayed remarkable reusability retaining 100% activity even after 15 cycles. Surface displayed BhCA displayed highly alkali stable nature like free counterpart in solution. The alkali stability of the surface-displayed BhCA was comparable to its free counterpart in solution. Furthermore, the study investigated the impact of different metal ions, modulators, and detergents on the whole-cell biocatalysts. The present work represents the first report on surface display of CA utilising the AIDA-1 autotransporter.

Evaluation of the Treatment Effects of Conditioned Medium from Human Orbital Adipose-Derived Stem Cells in a Corneal Alkali Burn Rabbit Model

Purpose: This study aimed to evaluate the effects of a new treatment-conditioned medium from human orbital adipose-derived stem cells (OASC-CM)-on corneal recovery after alkali burns in a rabbit model. Methods: The corneal alkali burn rabbit model was established and treated with OASC-CM, conditioned medium from human abdominal subcutaneous adipose-derived stem cells (ABASC-CM), and fresh control culture medium (con-CM) three times a day for 7 days, respectively. Subsequently, the treatment effects were evaluated and compared through clinical, histological, immunohistochemical, and cytokine evaluations. Results: Clinically, OASC-CM alleviated corneal opacity and edema and promoted recovery of corneal epithelium defect. Histologically and immunohistochemically, OASC-CM inhibited neovascularization, conjunctivalization, and immuno-inflammatory reaction, while promoting corneal regeneration and rearrangement. Increased secretion of interleukin-10 and inhibited protein levels of cluster of differentiation 45, interferon-γ, and tumor necrosis factor-α were observed in the alkali-burned cornea after OASC-CM treatment, which might be the relevant molecular mechanism. Conclusions: OASC-CM showed significant effects on the recovery of rabbit corneal alkali burns and eliminated immunological and ethical limitations, representing a new option for corneal wound treatment.

How does atmospheric pressure cold helium plasma affect the biomechanical behaviour on alkali-lesioned corneas?

BACKGROUND

Melting corneal ulcers are a serious condition that affects a great number of animals and people around the world and it is characterised by a progressive weakening of the tissue leading to possible severe ophthalmic complications, such as visual impairment or blindness. This disease is routinely treated with medical therapy and keratoplasty, and recently also with alternative regenerative therapies, such as cross-linking, amniotic membrane transplant, and laser. Plasma medicine is another recent example of regenerative treatment that showed promising results in reducing the microbial load of corneal tissue together with maintaining its cellular vitality. Since the effect of helium plasma application on corneal mechanical viscoelasticity has not yet been investigated, the aim of this study is first to evaluate it on ex vivo porcine corneas for different exposition times and then to compare the results with previous data on cross-linking treatment.

RESULTS

94 ex vivo porcine corneas divided into 16 populations (healthy or injured, fresh or cultured and treated or not with plasma or cross-linking) were analysed. For each population, a biomechanical analysis was performed by uniaxial stress-relaxation tests, and a statistical analysis was carried out considering the characteristic mechanical parameters. In terms of equilibrium normalised stress, no statistically significant difference resulted when the healthy corneas were compared with lesioned plasma-treated ones, independently of treatment time, contrary to what was obtained about the cross-linking treated corneas which exhibited more intense relaxation phenomena.

CONCLUSIONS

In this study, the influence of the Helium plasma treatment was observed on the viscoelasticity of porcine corneas ex vivo, by restoring in lesioned tissue a degree of relaxation similar to the one of the native tissue, even after only 2 min of application. Therefore, the obtained results suggest that plasma treatment is a promising new regenerative ophthalmic therapy for melting corneal ulcers, laying the groundwork for further studies to correlate the mechanical findings with corneal histology and ultrastructural anatomy after plasma treatment.

Inroads into saline-alkaline stress response in plants: unravelling morphological, physiological, biochemical, and molecular mechanisms

MAIN CONCLUSION

This article discusses the complex network of ion transporters, genes, microRNAs, and transcription factors that regulate crop tolerance to saline-alkaline stress. The framework aids scientists produce stress-tolerant crops for smart agriculture. Salinity and alkalinity are frequently coexisting abiotic limitations that have emerged as archetypal mediators of low yield in many semi-arid and arid regions throughout the world. Saline-alkaline stress, which occurs in an environment with high concentrations of salts and a high pH, negatively impacts plant metabolism to a greater extent than either stress alone. Of late, saline stress has been the focus of the majority of investigations, and saline-alkaline mixed studies are largely lacking. Therefore, a thorough understanding and integration of how plants and crops rewire metabolic pathways to repair damage caused by saline-alkaline stress is of particular interest. This review discusses the multitude of resistance mechanisms that plants develop to cope with saline-alkaline stress, including morphological and physiological adaptations as well as molecular regulation. We examine the role of various ion transporters, transcription factors (TFs), differentially expressed genes (DEGs), microRNAs (miRNAs), or quantitative trait loci (QTLs) activated under saline-alkaline stress in achieving opportunistic modes of growth, development, and survival. The review provides a background for understanding the transport of micronutrients, specifically iron (Fe), in conditions of iron deficiency produced by high pH. Additionally, it discusses the role of calcium in enhancing stress tolerance. The review highlights that to encourage biomolecular architects to reconsider molecular responses as auxiliary for developing tolerant crops and raising crop production, it is essential to (a) close the major gaps in our understanding of saline-alkaline resistance genes, (b) identify and take into account crop-specific responses, and (c) target stress-tolerant genes to specific crops.

Alleviation of cotton growth suppression caused by salinity through biochar is strongly linked to the microbial metabolic potential in saline-alkali soil

Biochar is a typical soil organic amendment; however, there is limited understanding of its impact on the metabolic characteristics of microorganisms in saline-alkaline soil microenvironment, as well as the advantages and disadvantages of plant-microorganism interactions. To elucidate the mechanisms underlying the impact of saline-alkali stress on cotton, a 6-month pot experiment was conducted, involving the sowing of cotton seedlings in saline-alkali soil. Three different biochar application levels were established: 0 % (C0), 1 % (C1), and 2 % (C2). Results indicated that biochar addition improved the biomass of cotton plants, especially under C2 treatment; the dry weight of cotton bolls were 8.15 times that of C0. Biochar application led to a rise in the accumulation of photosynthetic pigments by 8.30-51.89 % and carbohydrates by 7.4-10.7 times, respectively. Moreover, peroxidase (POD) activity, the content of glutathione (GSH), and ascorbic acid (ASA) were elevated by 23.97 %, 118.39 %, and 48.30 % under C2 treatment, respectively. Biochar caused a reduction in Na+ uptake by 8.21-39.47 %, relative electrical conductivity (REC) of plants, and improved K+/Na+ and Ca2+/Na+ ratio indicating that biochar alleviated salinity-caused growth reduction. Additionally, the application of biochar enhanced the absorption intensity of polysaccharide fingerprints in cotton leaves and roots. Two-factor co-occurrence analysis indicated that the key differential metabolites connected to several metabolic pathways were L-phenylalanine, piperidine, L-tryptophan, and allysine. Interestingly, biochar altered the metabolic characteristics of saline-alkali soil, especially related to the biosynthesis and metabolism of amino acids and purine metabolism. In conclusion, this study demonstrates that biochar may be advantageous in saline soil microenvironment; it has a favorable impact on how plants and soil microbial metabolism interact.

Effect of Arbuscular Mycorrhizal Fungi (AMF) on photosynthetic characteristics of cotton seedlings under saline-alkali stress

The study aimed to find the best Arbuscular Mycorrhizal Fungi (AMF) strain for cotton growth in Xinjiang's salinity and alkali conditions. Cotton (Xinluzao 45) was treated with Funneliformis mosseae (GM), Rhizophagus irregularis (GI), and Claroideoglomus etunicatum (GE) as treatments, while untreated cotton served as the control (CK). Salinity stress was applied post-3-leaf stage in cotton. The study analyzed cotton's reactions to diverse saline-alkali stresses, focusing on nutrient processes and metabolism. By analyzing the growth and photosynthetic characteristics of plants inoculated with Funneliformis mosseae to evaluate its salt tolerance. Saline-alkali stress reduced chlorophyll and hindered photosynthesis, hampering cotton growth. However, AMF inoculation mitigated these effects, enhancing photosynthetic rates, CO2 concentration, transpiration, energy use efficiency, and overall cotton growth under similar stress levels. GM and GE treatments yielded similar positive effects. AMF inoculation enhanced cotton plant height and biomass. In GM treatment, cotton exhibited notably higher root length than other treatments, showing superior growth under various conditions. In summary, GM-treated cotton had the highest infection rate, followed by GE-treated cotton, with GI-treated cotton having the lowest rate (GM averaging 0.95). Cotton inoculated with Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus etunicatum juvenile showed enhanced chlorophyll and photosynthetic levels, reducing salinity effects. Funneliformis mosseae had the most significant positive impact.

Alkali injury-induced pathological lymphangiogenesis in the iris facilitates the infiltration of T cells and ocular inflammation

Inflammatory lymphangiogenesis is intimately linked to immune regulation and tissue homeostasis. However, current evidence has suggested that classic lymphatic vessels are physiologically absent in intraocular structures. Here, we show that neolymphatic vessels were induced in the iris after corneal alkali injury (CAI) in a VEGFR3-dependent manner. Cre-loxP-based lineage tracing revealed that these lymphatic endothelial cells (LECs) originate from existing Prox1+ lymphatic vessels. Notably, the ablation of iridial lymphangiogenesis via conditional deletion of VEGFR3 alleviated the ocular inflammatory response and pathological T cell infiltration. Our findings demonstrate that iridial neolymphatics actively participate in pathological immune responses following injury and suggest intraocular lymphangiogenesis as a valuable therapeutic target for the treatment of ocular inflammation.

Experimental study on municipal solid waste incineration bottom ash as a component of alkali-activated coal gangue-based geopolymer

This study explores the potential of municipal solid waste incineration bottom ash (MSWI BA) and coal gangue as precursors for alkali-activated cementitious materials (CG-MBA). An examination of the impact of MSWI BA content, NaOH/Na2SiO3 ratio, liquid-solid ratio, and NaOH concentration on strength and reaction through the application of diverse analytical methodologies. Results demonstrate that CG-MBA offers significant environmental benefits compared to conventional cement. When used as a construction filling material, CG-MBA exhibits a remarkable 74.5 ~ 79.2 wt% reduction in carbon dioxide emissions and 70.6 ~ 77.0 wt% reduction in energy consumption. Additionally, CG-MBA effectively immobilizes heavy metal ions in MSWI BA, with a fixation efficiency exceeding 56.0%. These findings suggest that CG-MBA is a promising sustainable solution for waste management, offering significant environmental benefits while demonstrating effective heavy metal immobilization. This approach contributes to pollution control and promotes environmental sustainability in the construction industry.

Effects of alkali and alkaline earth metals on co-combustion of sewage sludge and coal slime: Combustion characteristics, interactions, and kinetics

The co-combustion of sewage sludge (SS) and coal slime (CS) is a preferred method for their resource utilization, however, alkali and alkaline earth metals (AAEMs) in SS may affect the co-combustion process. In this work, the co-combustion behavior of AAEMs-rich SS and CS was investigated in terms of combustion characteristics, interactions, and combustion kinetics using a thermogravimetric analyzer. Further, the role of AAEMs in co-combustion was evaluated by loading Ca, K, Na, and Mg individually after pickling. The results revealed that co-combustion compensated for the limitations of the individual combustion processes, with SS reducing ignition and burnout temperatures and CS improving the comprehensive combustion characterization. Principal component analysis (PCA) showed that the effect of CS on co-combustion was more significant compared to SS. Significant synergies were observed in the weight loss phase of fixed carbon in the blends with 40%, 50%, and 60% CS ratios, where the peak temperature of fixed carbon combustion was reduced by 9.8 °C, 12.6 °C, and 13.1 °C, respectively, compared to the theoretical values. The effects of AAEMs on combustion were as follows: all AAEMs promoted the precipitation of volatiles except Ca, which showed inhibition of light volatiles; AAEMs had a significant catalytic effect on fixed carbon combustion. The improvement effect of AAEMs on the comprehensive combustion characteristics during co-combustion was Na > K > Mg > Ca. The catalytic effect of Na on fixed carbon was strongest at a loading of 5%, leading to a decrease in the apparent activation energy of fixed carbon combustion by 22.2 kJ/mol and a change in reactor order from n = 1 to n = 1.2 during co-combustion. This work provides a better understanding of the role of AAEMs in SS-CS co-combustion.

Carbon-rich and low-ash hydrochar formation from sewage sludge by alkali-thermal hydrolysis coupled with acid-assisted hydrothermal carbonization

The production of carbon-rich and low-ash hydrochar from sewage sludge is attracting interest due to its great application prospect in high value-added carbon materials fields, but which is impossible through direct hydrothermal carbonization. In this study, alkali-thermal hydrolysis followed by acid-assisted hydrothermal carbonization was thus proposed. Thermal hydrolysis at strong alkaline environment was more effective than acid one to promote the dissolution of organic matters and restrain the release of inorganic matters from sludge, which created a favorable condition for hydrochar formation in a carbon-rich and low-ash way. Alkali-thermal hydrolysis began to show a positive effect on the dissolution of organics in sludge when temperature exceeded the threshold of 90 °C, and an increase of 9.77 % was found at 150 °C when compared to 30 °C. Acid-assisted hydrothermal carbonization of alkali-thermal hydrolysate (ATH) at pH 1.0 strongly promoted condensation polymerization of dissolved organics to form hydrochar and meanwhile inhibited introduction of dissolved inorganics. The nanosized microparticulate hydrochar derived from ATH-30 had a carbon and ash content of 50.98-61.31 % and 10.76-12.09 %, while the micro-sized microspheric hydrochar with multiple deposition layers formed from ATH-150 showed a better performance in carbon-rich and low-ash aspect where a carbon and ash content of 58.24-70.07 % and 0.40-3.24 % was realized, both of which were obviously superior to the direct hydrochar (carbon 34.86 % and ash 46.11 %). The condensation of dissolved organics during alkali-thermal hydrolysis stage is important to the carbonization degree of hydrochar. This study provides a new perspective in sludge disposal and production of advanced carbon materials.

Quality variation and salt-alkali-tolerance mechanism of Cynomorium songaricum: Interacting from microbiome-transcriptome-metabolome

Addressing soil salinization and implementing sustainable practices for cultivating cash crops on saline-alkali land is a prominent global challenge. Cynomorium songaricum is an important salt-alkali tolerant medicinal plant capable of adapting to saline-alkali environments. In this study, two typical ecotypes of C. songaricum from the desert-steppe (DS) and saline-alkali land (SAL) habitats were selected. Through the integration of multi-omics with machine learning, the rhizosphere microbial communities, genetic maps, and metabolic profiles of two ecotypes were created and the crucial factors for the adaptation of C. songaricum to saline-alkali stress were identified, including 7 keystone OTUs (i.e. Novosphingobium sp., Sinorhizobium meliloti, and Glycomyces sp.), 5 core genes (cell wall-related genes), and 10 most important metabolites (i.e. cucurbitacin D and 3-Hydroxybutyrate) were identified. Our results indicated that under saline-alkali environments, the microbial competition might become more intense, and the microbial community network had the simple but stable structure, accompanied by the changes in the gene expression related to cell wall for adaptation. However, this regulation led to the reduction in active ingredients, such as the accumulation of flavonoids and organic acid, and enhanced the synthesis of bitter substances (cucurbitacin D), resulting in the decrease in the quality of C. songaricum. Therefore, compared to the SAL ecotype, the DS was more suitable for the subsequent development of medicinal and edible products of C. songaricum. Furthermore, to explore the reasons for this quality variation, we constructed a comprehensive microbial-genetic-metabolic regulatory network, revealing that the metabolism of C. songaricum was primarily influenced by genetic factors. These findings not only offer new insights for future research into plant salt-alkali tolerance strategies but also provide a crucial understanding for cultivating high-quality medicinal plants.

Effect of chemical treatments of arundo donax L. fibre on mechanical and thermal properties of the PLA/PP blend composite filament for FDM 3D printing

Arundo donax L. is investigated in this study as a suitable reinforcing agent for PLA/PP waste blend 3D printing filament. To improve the compatibility of the fibre and polymer, the Arundo fibre was chemically modified using alkali and silane treatment. Untreated and treated fibres were extruded with Polymer blends before being 3D printed. Effect of chemical treatment on thermal, mechanical, and morphological properties of the composites was investigated. The tensile, Izod impact, and water absorption of the 3D printed specimens were also tested. The Alkali treated (ALK) and combination of alkali and silane treatment (SLN) composites displayed good results. Tensile strength and modulus of the materials increased, as well as their maintained stability in the Izod impact test, demonstrating that the incorporation of ArF did not result in a loss in performance. SEM examination supported these findings by confirming the creation of beneficial interfacial contacts between the matrix and fibre components, as demonstrated by the lack of void between the matrix and the fibre surface. Furthermore, the alkali treatment of the ArF resulted in a considerable reduction in water absorption inside the biocomposite, with a 64% reduction seen in ALK composite comparison to the untreated composite (Un). After the 43-day assessment period.

Ultrasonic-enhanced photocatalysis through piezoelectric and cavitation effects for lignin depolymerization

Although a promising method for lignin depolymerization, photocatalysis faces the challenge of low efficiency. In this study, MoS2/ZnO heterojunction catalysts, endowed with piezocatalysis and photocatalytic capabilities, were crafted through Zn ion intercalation for the depolymerization of phenoxyphenylethanol (PP-ol) and alkali lignin. Then, the synergistic interplay between ultrasonic-induced piezoelectric fields and heterojunctions was analyzed. The amalgamation of the piezoelectric field and heterojunction in MoS2/ZnO catalysts resulted in a diminished photogenerated hole/electron recombination efficiency, thereby fostering the generation of ·OH during the reaction. This pivotal role of ·OH emerged as a crucial reactive substance, converting 95.8 % of PP-ol through β-O-4 bond breaking within a 3-h treatment. By incorporating ultrasonic, the contact probability of PP-ol with the catalyst was significantly improved, resulting in efficient conversion even with a reduced amount of acetonitrile in the solvent system (20 %). Furthermore, ultrasonic-light methods show high efficiency for depolymerizing Alkali lignin (AL), with 33.2 % of lignin undergoing depolymerization in a 4-h treatment. This treatment simultaneously reduces the molecular weight of AL and cleaves numerous chemical bonds within it. Overall, this work presents a green approach to lignin depolymerization, providing insights into the synergistic action of ultrasonic and photocatalysis.

Minocycline-loaded nHAP/PLGA microspheres for prevention of injury-related corneal angiogenesis

BACKGROUND

Corneal neovascularization (CoNV) threatens vision by disrupting corneal avascularity, however, current treatments, including pharmacotherapy and surgery, are hindered by limitations in efficacy and adverse effects. Minocycline, known for its anti-inflammatory properties, could suppress CoNV but faces challenges in effective delivery due to the cornea's unique structure. Therefore, in this study a novel drug delivery system using minocycline-loaded nano-hydroxyapatite/poly (lactic-co-glycolic acid) (nHAP/PLGA) nanoparticles was developed to improve treatment outcomes for CoNV.

RESULTS

Ultra-small nHAP was synthesized using high gravity technology, then encapsulated in PLGA by a double emulsion method to form nHAP/PLGA microspheres, attenuating the acidic by-products of PLGA degradation. The MINO@PLGA nanocomplex, featuring sustained release and permeation properties, demonstrated an efficient delivery system for minocycline that significantly inhibited the CoNV area in an alkali-burn model without exhibiting apparent cytotoxicity. On day 14, the in vivo microscope examination and ex vivo CD31 staining corroborated the inhibition of neovascularization, with the significantly smaller CoNV area (29.40% ± 6.55%) in the MINO@PLGA Tid group (three times daily) than that of the control group (86.81% ± 15.71%), the MINO group (72.42% ± 30.15%), and the PLGA group (86.87% ± 14.94%) (p < 0.05). Fluorescein sodium staining show MINO@PLGA treatments, administered once daily (Qd) and three times daily (Tid) demonstrated rapid corneal epithelial healing while the Alkali injury group and the DEX group showed longer healing times (p < 0.05). Additionally, compared to the control group, treatments with dexamethasone, MINO, and MINO@PLGA were associated with an increased expression of TGF-β as evidenced by immunofluorescence, while the levels of pro-inflammatory cytokines IL-1β and TNF-α demonstrated a significant decrease following alkali burn. Safety evaluations, including assessments of renal and hepatic biomarkers, along with H&E staining of major organs, revealed no significant cytotoxicity of the MINO@PLGA nanocomplex in vivo.

CONCLUSIONS

The novel MINO@PLGA nanocomplex, comprising minocycline-loaded nHAP/PLGA microspheres, has shown a substantial capacity for preventing CoNV. This study confirms the complex's ability to downregulate inflammatory pathways, significantly reducing CoNV with minimal cytotoxicity and high biosafety in vivo. Given these findings, MINO@PLGA stands as a highly promising candidate for ocular conditions characterized by CoNV.

Order matters: Methods for extracting cellulose from rice straw by coupling alkaline, ozone and enzymatic treatments

Rice straw is a widely produced residue that can be converted into value-added products. This work aimed at using greener processes combining mild alkali (A), ozone (O) and enzymatic (engineered xylanase) (E) treatments to extract cellulose and other value-added compounds from rice straw and to evaluate the effects of the order of the treatments. Solid (S) and liquid (L) fractions from the process were collected for physicochemical characterization. AOE treatment showed the best capacity to extract high purity cellulose and other valuable compounds. The lignin content was significantly decreased independently of the order of the treatments and, its content in the extract obtained after the AOE process was lower than the one obtained after the OAE process. Moreover, thermal stability of the samples increased after the enzymatic process, being higher in SAOE. The alkaline treatment increased the hemicellulose and polyphenol content (antioxidant activity) in the liquid fractions (LA and LOA). In contrast, the ozonized liquid fractions had lower polyphenol content. Therefore, alkali was fundamental in the process. In conclusion, the AOE strategy could be a more environmentally friendly method for extracting cellulose and other valuable compounds, which could be used to develop active materials in the future.

Rh proteins and H+ transporters involved in ammonia excretion in Amur Ide (Leuciscus waleckii) under high alkali exposure

High alkaline environment can lead to respiratory alkalosis and ammonia toxification to freshwater fish. However, the Amur ide (Leuciscus waleckii), which inhabits an extremely alkaline lake in China with titratable alkalinity up to 53.57 mM (pH 9.6) has developed special physiological and molecular mechanisms to adapt to such an environment. Nevertheless, how the Amur ide can maintain acid-base balance and perform ammonia detoxification effectively remains unclear. Therefore, this study was designed to study the ammonia excretion rate (Tamm), total nitrogen accumulation in blood and tissues, including identification, expression, and localization of ammonia-related transporters in gills of both the alkali and freshwater forms of the Amur ide. The results showed that the freshwater form Amur ide does not have a perfect ammonia excretion mechanism exposed to high-alkaline condition. Nevertheless, the alkali form of Amur ide was able to excrete ammonia better than freshwater from Amur ide, which was facilitated by the ionocytes transporters (Rhbg, Rhcg1, Na+/H+ exchanger 2 (NHE2), and V-type H+ ATPase (VHA)) in the gills. Converting ammonia into urea served as an ammonia detoxication strategy to reduced endogenous ammonia accumulation under high-alkaline environment.

Reversible Deacidification and Preventive Conservation of Paper-Based Cultural Relics by Mineralized Bacterial Cellulose

Paper-based cultural relics experience irreversible aging and deterioration during long-term preservation. The most common process of paper degradation is the acid-catalyzed hydrolysis of cellulose. Nowadays, deacidification has been considered as a practical way to protect acidified literature; however, two important criteria of minimal intervention and reversibility should be considered. Inspired by the superior properties of bacterial cellulose (BC) and its structural similarity to paper, herein, the mineralized BC membranes are applied to deacidification and conservation of paper-based materials for the first time. Based on the enzyme-induced mineralization process, the homogeneous and high-loaded calcifications of hydroxyapatite (HAP) and calcium carbonate (CaCO3) nanoparticles onto the nanofibers of BC networks have been achieved, respectively. The size, morphology, structure of minerals, as well as the alkalinity and alkali reserve of BC membranes are well controlled by regulating enzyme concentration and mineralization time. Compared with HAP/CaCO3-immersed method, HAP/CaCO3-BC membranes show more efficient and sustained deacidification performance on paper. The weak alkalinity of mineralized BC membranes avoids the negative effect of alkali on paper, and the high alkali reserve implies a good sustained-release effect of alkali to neutralize the future generated acid. The multiscale nanochannels of the BC membrane provide ion exchange and acid/alkali neutralization channels between paper and the BC membrane, and the final pH of protected paper can be well stabilized in a certain range. Most importantly, this BC-deacidified method is reversible since the BC membrane can be removed without causing any damage to paper and the original structure and fiber morphology of paper are well preserved. In addition, the mineralized BC membrane provides excellent flame-retardant performance on paper thanks to its unique organic-inorganic composite structure. All of these advantages of the mineralized BC membrane indicate its potential use as an effective protection material for the reversible deacidification and preventive conservation of paper-based cultural relics.

Insight into the Alkali Resistance Mechanism of FeMoTiOx Catalysts for NH3 Selective Catalytic Reduction of NO: Self-Defense Effects of MoOx for Alkali Capture

The deactivation of selective catalytic reduction (SCR) catalysts caused by alkali metal poisoning remains an insurmountable challenge. In this study, we examined the impact of Na poisoning on the performance of Fe and Mo co-doped TiO2 (FeaMobTiOx) catalysts in the SCR reaction and revealed the related alkali resistance mechanism. On the obtained Fe1Mo2.6TiOx catalyst, the synergistic catalytic effect of uniformly dispersed FeOx and MoOx species leads to remarkable catalytic activity, with over 90% NO conversion achieved in a wide temperature range of 210-410 °C. During the Na poisoning process, Na ions predominantly adsorb on the MoOx species, which exhibit stronger alkali resistance, effectively safeguarding the FeOx species. This preferential adsorption minimizes the negative effect of Na poisoning on Fe1Mo2.6TiOx. Moreover, Na poisoning has little influence on the Eley-Rideal reaction pathway involving adsorbed NHx reacting with gaseous NOx. After Na poisoning, the Lewis acid sites were deteriorated, while the abundant Brønsted acid sites ensured sufficient NHx adsorption. As a benefit from the self-defense effects of active MoOx species for alkali capture, FeaMobTiOx exhibits exceptional alkali resistance in the SCR reaction. This research provides valuable insights for the design of highly efficient and alkali-resistant SCR catalysts.

Preparation and characterization of a novel high barrier mulching film with tunicate cellulose nanocrystals/sodium alginate/alkali lignin

In this study, the base film (CSL) was prepared by blending tunicate cellulose nanocrystals (TCNCs) extracted from tunicate shells, with sodium alginate (SA) and alkali lignin (AL). Then, the mulching film (CSL-WK) was prepared using water-borne polyurethane (WPU) as binder to install low-energy Kaolin on the surface of CSL film. The influences of composition with different concentrations on mechanical properties were studied. The tensile strength and elongation at break of CSL-WK film could reach 86.58 MPa and 50.49 %, respectively. The mulching films were characterized by degradability test, SEM, FTIR, and TGA. TCNCs had good compatibility with SA and AL, and a rough structure was formed on the surface of the film to improve the hydrophobicity. The barrier properties, including ultraviolet resistance, water contact angle, water vapor permeability, water retention, and flame retardancy, were tested. The results showed that CSL-WK films could block 97 % of ultraviolet light, reduce about 25 % of soil water loss, and self-extinguish within 7 s of open flame ignition. Note that the secondary spraying method significantly improved the barrier property of films. This study lays a foundation for the preparation of ecologically friendly, biodegradable, and high barrier mulching film, and expands the application of marine resources.

Alginate-coated pomelo pith cellulose matrix for probiotic encapsulation and controlled release

A novel carrier comprised of ethanol- and alkali-modified cellulosic pomelo pith matrix coated with alginate was developed to improve viability while enabling gastrointestinal release of probiotics. Scanning electron microscopy imaging revealed the agricultural byproduct had a honeycomb-structured cellulose framework, enabling high loading capacity of the probiotic Lactobacillus plantarum up to 9 log CFU/g. Ethanol treatment opened up pores with an average diameter of 97 μm, while alkali treatment increased swelling and porosity, with an average pore size of 51 μm. The survival rate through the stomach was increased from 89.76 % to 91.08 % and 91.24 % after ethanol and alkali modification, respectively. The control group displayed minimal release in the first 4 h followed by a burst release. Both ethanol modification and alkali modification resulted in constant linear release over time. The release time was prolonged when decreasing the width of the pomelo peel rolls from 10 mm to 5 mm while keeping the volume of the peel constant. After 8 weeks of refrigerated storage, the cellulose-encapsulated probiotics retained viability above 7 log CFU/g. This study demonstrates the potential of the structurally intact, sustainably-sourced cellulosic pomelo pith for probiotic encapsulation and controlled delivery.

Reclaimed seawater discharge - Desalination brine treatment and resource recovery system

With the proliferation of reverse osmosis technology, seawater reverse osmosis desalination has been heralded as the solution to water scarcity for coastal regions. However, the large volume of desalination brine produced may pose an adverse environmental impact when directly discharged into the sea and result in energy wastage as the seawater pumped out is dumped back into the sea. Recently, zero liquid discharge has been extensively studied as a way to eliminate the aquatic ecotoxicity impact completely, despite being expensive and having a high carbon footprint. In this work, we propose a new strategy towards the treatment of brine to seawater level for disposal, dubbed reclaimed seawater discharge (RSD). This process is coupled with existing resource recovery techniques and waste alkali CO2 capture processes to produce an economically viable waste treatment process with minimal CO2 emissions. In this work, we placed significant focus on the electrolysis of brine, which simultaneously lowers the salinity of the desalination brine (56.0 ± 2.1 g/L) to seawater level (32.0 ± 1.4 g/L), generates alkali brine from seawater (pH 13.6) to remove impurities in brine (Mg2+ and Ca2+ to below ppm level), and recovers magnesium hydroxide, calcium carbonate, chlorine, bromine, and hydrogen gas as valuable resources. The RSD is further chemically dechlorinated and neutralised to pH 7.3 to be safe to discharge into the sea. The excess alkali brine is used to capture additional CO2 in the form of bicarbonates, achieving net abatement in climate change impact (9.90 CO2 e/m3) after product carbon abatements are accounted.

Pretreatment of alkali/surfactant/polymer (ASP)-flooding produced wastewater by electron beam radiation to improve oil-water separation

The management of wastewater produced from alkali/surfactant/polymer (ASP) flooding, known for its considerable volume and high emulsion stability, poses a challenge in oilfields globally. This study has demonstrated that ionizing irradiation is a promising pretreatment method for ASP wastewater to improve oil-water separation. After a settling time of 1 h, approximately 69.5% of oil remained in the raw ASP wastewater, while only 20-29% of the oil persisted in the liquid phase following radiation at absorbed doses ranging from 0.1 to 5.0 kGy. A noticeable increase in the size of oil droplets and reduction in turbidity was observed after irradiation. Further analysis revealed that the combination of surfactant, sodium dodecyl sulfate (SDS) and alkali exhibits a synergistic impact, leading to a substantial reduction in interface tension of ASP wastewater. Notably, ionizing irradiation induces several key changes that are crucial for efficient demulsification. The transformation of the wastewater's rheological behavior from pseudoplastics to a Newtonian fluid accompanied by a reduction in viscosity, the increased interfacial tension at both liquid-air and liquid-oil interfaces, along with the degradation of organic components such as partly hydrolyzed polyacrylamide (HPAM) and SDS, all contribute to the coalescence and floatation of oil droplets.

Quantifying plasmonic characteristics of pure and alkali doped aluminium clusters

Study of plasmonic response of molecules and metal nanoclusters have drawn a considerable attention during recent times due to their various practical applications. In this study, the optical properties and the plasmonic response of our recently reported Al13+ cluster [Guin et al. Journal of Molecular Graphics and Modelling, 2020, 97, 107544] and its alkali doped counterparts [Guin et al. Journal of Molecular Modeling, 2021, 27, 235] have been investigated based on Transition dipole moment (TDM), Natural Transition Orbital (NTO) and transition inverse participation ratio (TIPR) indices. Recently these indices have been utilized by various scientists to characterize plasmonic transitions of molecular systems and metal nanoclusters. In TDM analysis, the magnitude of all the contributing TDMs associated with the molecular orbital transitions have been estimated along with the angles the individual dipoles make with the resultant dipole moment vector. A transition having at least two dominating TDM contributions along with phase matching indicate a collective or plasmonic transition. The collectiveness of orbital transitions is also corroborated through NTO and TIPR analysis. The effect of solvent medium on the optical properties and plasmonic transitions have also been studied using time dependent density functional theory in the conductor like polarizable continuum model (TDDFT-CPCM). The solvent has a strong impact on the optical properties as well as the plasmonic response of the clusters. The dielectric environment of the solvent red shifts and broadens the spectra with respect to that in the gas phase. Plasmon like excitations have been found for Li doped Al13+ cluster without solvent and Na doped Al13+ cluster in ethanol and THF.

Deep resource utilization of hazardous arsenic-alkali slag: Thermodynamic analysis, mechanism investigation and process optimization

The best solution to address environmental pollution caused by arsenic-containing hazardous waste is to prepare high-purity elemental arsenic from such waste. The key to this approach lies in the efficient separation of arsenic from various impurities. This paper presents a viable solution for producing high-purity elemental arsenic from arsenic-alkali slag, and the keylies in utilizing the selective precipitation of magnesium ammonium arsenate (MgNH4AsO4) to achieve efficient separation of arsenic from alkali, antimony, and other impurities. Thermodynamic analysis and hydrometallurgical condition experiments indicate that in complex alkaline arsenic-containing solutions, over 90% of arsenic components can selectively precipitate in the form of MgNH4AsO4. The content of arsenic in the resulting precipitate reaches approximately 30%, while the content of antimony is below 0.1%. This achieves efficient enrichment of arsenic and preliminary separation of impurities in complex arsenic-alkali slag. Thermodynamic analysis and pyrometallurgical condition experiments demonstrate that the precipitate of MgNH4AsO4 can be reduced to elemental arsenic with an arsenic content reaching 99.85%, and an antimony content as low as 0.05%. This achieves a profound separation of arsenic from impurities. Based on the research presented in this paper, a production line was established that enables the deep resource utilization of arsenic-alkali slag.

Effect of alkali treatment on enzymatic hydrolysis of p-toluenesulfonic acid pretreated bamboo substrates

The comprehensive separation and utilization of whole components of lignocellulosic materials has received extensive attention in present research. This study focused on the efficacy of alkali treatment for enzymatic saccharification of cellulose based on p-toluenesulfonic acid (p-TsOH) pretreated bamboo substrate. The results showed that the cellulose to glucose conversion yield was 94.69 % under optimized conditions of 0.4 g NaOH/g, 160 °C and 4 h (soaked), which after only 6 h enzymatic hydrolysis time. Alkali lignin recovery was 88.51 %, with potential for conversion to lignin derivatives. The yield of hemicellulose in the pretreated filtrate was 51.85 % after the 4th cycling reuse of p-TsOH. This work has borrowed the advantages of p-TsOH pretreatment of depolymerized hemicellulose from bamboo, combined with a low-priced weak alkali secondary treatment method, which can be effectively applied to the co-production of lignin, xylooligosaccharide, xylose and glucose, and the whole process is green and economically sustainable.

Green Synthesis, Characterization, Encapsulation, and Measurement of the Release Potential of Novel Alkali Lignin Micro-/Submicron Particles

The applicability of biopolymer micro-/nano- technology in human, veterinary medicine, pharmaceutical, and food technology is rapidly growing due to the great potential of biopolymer-based particles as effective carrier systems. The use of lignin as a basic heteropolymer biomatrix for the design of innovative micro-/submicron formulations allows the achievement of increased biocompatibility and offers various active functional groups presenting opportunities for customization of the physicochemical properties and bioactivities of the formulations for diverse applications. The aim of the present study was to develop a simple and ecofriendly methodology for the synthesis of lignin particles with micro- and submicron size; to evaluate their physicochemical, spectral, and structural characteristics; and to examine their capacity for encapsulation of biologically active molecules and potential for in vitro release of bioflavonoids in simulated gastrointestinal media. The presented methodologies apply cheap and green solvents; easy, straightforward, quick, and sensitive processes requiring little equipment, non-toxic substances, and simple methods for their characterization, the determination of encapsulation capacity towards the poorly water-soluble bioactive compounds morin and quercetin, and the in vitro release potential of the lignin matrices.

Near-ultraviolet photon-counting dual-comb spectroscopy

Ultraviolet spectroscopy provides unique insights into the structure of matter with applications ranging from fundamental tests to photochemistry in the Earth's atmosphere and astronomical observations from space telescopes1-8. At longer wavelengths, dual-comb spectroscopy, using two interfering laser frequency combs, has become a powerful technique capable of simultaneously providing a broad spectral range and very high resolution9. Here we demonstrate a photon-counting approach that can extend the unique advantages of this method into ultraviolet regions where nonlinear frequency conversion tends to be very inefficient. Our spectrometer, based on two frequency combs with slightly different repetition frequencies, provides a wide-span, high-resolution frequency calibration within the accuracy of an atomic clock, and overall consistency of the spectra. We demonstrate a signal-to-noise ratio at the quantum limit and an optimal use of the measurement time, provided by the multiplexed recording of all spectral data on a single photon-counter10. Our initial experiments are performed in the near-ultraviolet and in the visible spectral ranges with alkali-atom vapour, with a power per comb line as low as a femtowatt. This crucial step towards precision broadband spectroscopy at short wavelengths paves the way for extreme-ultraviolet dual-comb spectroscopy, and, more generally, opens up a new realm of applications for photon-level diagnostics, as encountered, for example, when driving single atoms or molecules.

Conocimientos sobre COVID-19 en población general adulta tras dos años de pandemia

OBJETIVO

identificar el nivel de conocimientos sobre la COVID-19 que tiene la población adulta residente en Gijón (España) después de dos años de pandemia.

MÉTODOS

se realizó un estudio descriptivo transversal entre marzo del 2021 y marzo del 2022. Los datos se obtuvieron mediante un cuestionario telefónico sobre una muestra estratificada de tres zonas básicas de salud de Gijón, España (Calzada, Zarracina y Parque-Somió). El tamaño muestral se compuso de 305 personas. Se empleó el análisis ji-cuadrado para estudiar la relación entre variables categóricas y ANOVA para comparar las medias de la puntuación total por zona básica. Se realizaron regresiones logísticas para calcular las odds ratio entre la variable dependiente (poseer conocimientos avanzados) y las independientes (variables sociodemográficas). Se construyó un modelo predictivo entre la existencia o no de conocimiento avanzado y las variables independientes mediante regresión logística.

RESULTADOS

se encontraron diferencias en la puntuación media del nivel de conocimientos entre Parque-Somió y Calzada (p = 0.000) y Parque-Somió y Zarracina (p = 0.045), obteniendo mayor puntuación media la de Parque-Somió. Se observó una asociación entre el nivel de conocimientos y las variables medio de información utilizado (p = 0.018), edad (p = 0.036), zona básica de salud (p = 0.000), nivel educativo (p = 0.000) e historia previa de contacto estrecho (p = 0.004).

CONCLUSIONES

el nivel de conocimientos avanzado se presenta sobre todo en las zonas básicas de salud con mayor nivel socioeconómico, población con nivel educativo alto, de 25 a 45 años, que se ha informado por su entorno y con historia previa de seguimiento por ser contacto estrecho.

Genome-wide identification and characterization of FAD family genes in barley

Fatty acid desaturases (FADs) play pivotal roles in determining plant stress tolerance. Barley is the most salt-tolerant cereal crop. In this study, we performed genome-wide identification and characterization analysis of the FAD gene family in barley (Hordeum vulgare). A total of 24 HvFADs were identified and divided into four subfamilies based on their amino acid sequence similarity. HvFADs unevenly distributed on six of seven barley chromosomes, and three clusters of HvFADs mainly occurred on the chromosome 2, 3 and 6. Segmental duplication events were found to be a main cause for the HvFAD gene family expansion. The same HvFAD subfamily showed the relatively consistent exon-intron composition and conserved motifs of HvFADs. Cis-element analysis in HvFAD promoters indicated that the expression of HvFADs may be subject to complex regulation, especially stress-responsive elements that may involve in saline-alkaline stress response. Combined transcriptomic data with quantitative experiments, at least five HvFADs highly expressed in roots under salt or alkali treatment, suggesting they may participate in saline or alkaline tolerance in barley. This study provides novel and valuable insights for underlying salt/alkali-tolerant mechanisms in barley.

The effect of modifier and a water-soluble fertilizer on two forages grown in saline-alkaline soil

Saline-alkali soil significantly impairs crop growth. This research employs the impacts of the modifier and water-soluble fertilizer, as well as their interaction, on the root systems of alfalfa and leymus chinensis in saline-alkali soil. The results exhibit that the hydrochar source modifier effectively enhances the root growth of both forage species. There are certain improvements in the root growth indicators of both crops at a dosage of 20 g/kg. Root enzyme activity and rhizosphere soil enzyme activity are enhanced in alfalfa, showing significant improvements in the first planting compared to the second planting. The application of water-soluble fertilizers also promotes root growth and root dehydrogenase activity. The root dehydrogenase activity of alfalfa and leymus chinensis are enhanced 62.18% and 10.15% in first planting than that of blank, respectively. Additionally, the two-factor variance analysis revealed a correlation between rhizosphere soil enzyme activity and changes in root traits. Higher rhizosphere soil enzyme activity is observed in conjunction with better root growth. The combined application of a modifier and water-soluble fertilizer has demonstrated a significant interaction effect on various aspects of the first planting of alfalfa and leymus chinensis. Moreover, the combined application of the modifier and water-soluble fertilizer has yielded superior results when compared to the individual application of either the modifier or the water-soluble fertilizer alone. This combined approach has proven effective in improving saline-alkali soil conditions and promoting crop growth in such challenging environments.

Vegetative cell wall protein OsGP1 regulates cell wall mediated soda saline-alkali stress in rice

Plant growth and development are inhibited by the high levels of ions and pH due to soda saline-alkali soil, and the cell wall serves as a crucial barrier against external stresses in plant cells. Proteins in the cell wall play important roles in plant cell growth, morphogenesis, pathogen infection and environmental response. In the current study, the full-length coding sequence of the vegetative cell wall protein gene OsGP1 was characterized from Lj11 (Oryza sativa longjing11), it contained 660 bp nucleotides encoding 219 amino acids. Protein-protein interaction network analysis revealed possible interaction between CESA1, TUBB8, and OsJ_01535 proteins, which are related to plant growth and cell wall synthesis. OsGP1 was found to be localized in the cell membrane and cell wall. Furthermore, overexpression of OsGP1 leads to increase in plant height and fresh weight, showing enhanced resistance to saline-alkali stress. The ROS (reactive oxygen species) scavengers were regulated by OsGP1 protein, peroxidase and superoxide dismutase activities were significantly higher, while malondialdehyde was lower in the overexpression line under stress. These results suggest that OsGP1 improves saline-alkali stress tolerance of rice possibly through cell wall-mediated intracellular environmental homeostasis.

Effect of micro-nano bubbles on the remediation of saline-alkali soil with microbial agent

The widespread distribution of saline-alkali soil around the world affects the health of ecological systems and the development of the national economy by limiting the growth of plants. However, the commonly used remediation technologies have the drawbacks of low efficiency, high cost, and secondary pollution. This study investigated the feasibility and efficacy of novel combined micro-nanobubbles (MNBs) and microbial agent (MA) technology for the remediation of saline-alkali soil. The results demonstrated that the combined MA-MNBs method greatly renovated the properties of saline-alkali soil compared with the technologies of single utilization of MA or MNBs process in the laboratory. The method resulted in a reduction of soil electrical conductivity and pH levels, an improvement in soil fertility, and the formation of soil aggregates. Moreover, the method significantly impacted the growth of plants, particularly in plant length, dry weight, and rhizome elongation. Further high-throughput sequencing and gene expression analysis revealed that the MA-MNBs method enhanced the abundance of soil microbial community compared with single MA and MNBs treatment. Gene enrichment analysis revealed that the MA-MNBs method could compensate for the shortcomings of single MA treatment and enhance the expression of energy metabolism and salt stress-related genes attributed to MNBs treatment, thereby significantly improving the growth and development of plants. Consistently, 6115 kg/ha of rice was yielded in the field for the saline-alkali soils using this MA-MNBs method, with zero crops before remediation. This study provided a novel, efficient, and green strategy for the remediation of saline-alkali soil without adding any chemicals.

Application of carboxymethyl cellulose sodium (CMCNa) in maize-wheat cropping system (MWCS) in coastal saline-alkali soil

Sodium carboxymethyl cellulose (CMCNa) application has been a promising approach to improve soil quality. The purpose of this study was to explore the effects of CMC-Na on soil infiltration, evaporation, water-salt distribution, crop growth, water use efficiency and net profit (Net) in a coastal saline-alkali soil maize-wheat cropping system (MWCS). Five CMC-Na application amounts (0, 0.1, 0.2, 0.4 and 0.6 g kg-1) were designed for the soil column experiment indoor, and five CMC-Na application amounts were used in 2019-2020 field experiment (CK: 0, C10: 10 kg ha-1, C20: 10 kg ha-1, C30: 10 kg ha-1 and C50: 10 kg ha-1), No treatment will be applied in 2021. The results showed that (1) CMC-Na treatment reduced soil cumulative infiltration, infiltration rate, daily evaporation, and cumulative evaporation. (2) After the application of CMCNa, the average soil water storage (SWS) in the 0-60 cm soil layer increased, and soil salinity (SSC) decreased in most treatments. (3) In the 2019-2020, the maize aboveground biomass (B), yield (Y) and water use efficiency (WUE) were the highest under the C20 and C30 treatments, which were 15.24 and 15.32 t ha-1, 5.67 and 5.49 t ha-1 and 1.74 and 1.52 kg ha-1 mm-1, respectively, and the wheat under C30 treatment is the highest, which were 10.98 t ha-1, 5.27 t ha-1 and 1.78 kg ha-1 mm-1. (4) A dose of 25.5 kg ha-1 and 38.9 kg ha-1 was recommended as the most optimal CMC-Na application for maize and wheat in coastal saline alkali soil, respectively.

Alterations in the composition and metabolite profiles of the saline-alkali soil microbial community through biochar application

Saline-alkali soil poses significant chanllenges to sustainable development of agriculture. Although biochar is commonly used as a soil organic amendment, its microbial remediation mechanism on saline-alkali soil requires further confirmation. To address this, we conducted a pot experiment using cotton seedlings to explore the potential remediation mechanism of rice straw biochar (BC) at three different levels on saline-alkaline soil. The results showed that adding of 2% biochar greatly improved the quality of saline-alkaline soil by reducing pH levels, electrical conductivity (EC), and water-soluble ions. Moreover, biochar increased the soil organic matter (SOM), nutrient availability and extracellular enzyme activity. Interestingly, it also reduced soil salinity and salt content in various cotton plant tissues. Additionally, biochar had a notable impact on the composition of the microbial community, causing changes in soil metabolic pathways. Notably, the addition of biochar promoted the growth and metabolism of dominant salt-tolerant bacteria, such as Proteobacteria, Bacteroidota, Acidobacteriota, and Actinobacteriota. By enhancing the positive correlation between microorganisms and metabolites, biochar alleviated the inhibitory effect of salt ions on microorganisms. In conclusion, the incorporation of biochar significantly improves the soil microenvironment, reduces soil salinity, and shows promise in ameliorating saline-alkaline soil conditions.

Investigation of pre-treatment techniques on spent substrate of Pleurotus ostreatus for enhanced biobutanol production using Clostridium acetobutylicum MTCC 11274

Addressing global energy demand, researchers sought eco-friendly biobutanol production from lignocellulosic waste biomass. In the present research work, five different pre-treatment methods viz., Microwave, Ultrasound, Alkali, Acid, and Hybrid, were investigated to explore its biobutanol production potential by utilizing Pleurotus ostreatus spent as substrate. The compositional and physico-chemical changes of the pre-treated Spent Mushroom Substrate (SMS) were assessed using SEM, FTIR, and XRD. Hybrid pre-treatment (Microwave, Alkali, Ultrasound) showed higher delignification when compared to conventional pre-treatment method. Hybrid pre-treated SMS resulted in higher total reducing sugars (521.53 ± 1.84 mg/g) than indigenous SMS (267.89 ± 1.53 mg/g). Fermentation of hybrid pre-treated SMS with Clostridium acetobutylicum MTCC 11274 produced the highest biobutanol concentration (9.84 ± 0.03 g/L) and yielded 0.38 ± 0.02 g/g of biobutanol. This study revealed that hybrid pre-treatment could be a promising solution for enhanced biobutanol production using SMS biomass.

Environmental, economic, and social impacts of sugar cane bagasse and eggshell wastes for soil stabilization

Sustainability is a core topic for all sectors including geotechnical engineering (e.g., design of foundations, earthworks structures, and pavements for major infrastructure and building projects). Despite being comprised of environmental, economic, and social pillars, most sustainability studies in this area have focused on the first. Furthermore, social impacts and the three pillars integration are little explored. As a result, there is a lack of systemic and holistic assessments of innovative geotechnical alternatives. This research advances in this area by performing a complete sustainability assessment and integration of the environmental, economic, and social pillars of two expansive soil stabilization alternatives: (i) sugar cane bagasse ash combined with hydrated eggshell lime alkali-activated by sodium hydroxide (NaOH) and (ii) Portland cement. Individual analyses were carried out to determine the environmental, economic, and social impacts, and the single sustainability index. Alkali-activated binder dosages showed higher impacts in 4 out of 10 environmental categories. For both binders, high-density/low-binder dosages contributed to environmental and economic sustainability as they require lower quantities of raw materials and diesel for materials transportation. The total costs of alkali-activated binder dosages ($189.79 and $154.45) were higher than that of Portland cement ($72.49 and $54.04), mainly due to the high cost of NaOH acquisition. However, the alkali-activated binder dosages implied lower carbon dioxide (CO2) emissions and thus lower social cost of CO2. The alternative binder presented a higher positive social impact. The alkali-activated high-density/low binder dosage is the most sustainable soil stabilization strategy.

Effects of cation types in persulfate on physicochemical and adsorptive properties of biochar prepared from persulfate-pretreated bamboo

The adsorption behaviors of biochar are largely impacted by biomassfeedstock. In this study, two biochars were prepared from torrefaction of ammonium persulfate- and potassium persulfate-pretreated bamboo and then activated by cold alkali, which are named as ASBC and KSBC, respectively. The two biochars were characterized by different instruments, and their adsorption properties over cationic methylene blue (MB) were compared. The type of persulfates little affected the specific surface areas, but significantly impacted O (29.54 % vs. 35.113 %) and N (12.13 % vs. 3.74 %) contents, functional groups, and zeta potentials of biochars. MB adsorption onto ASBC/KSBC is a single-layer chemical endothermic process and ASBC/KSBC exhibit high adsorption capacity over MB (475/881 mg·g-1) at 303 K. Obviously, the sorption capacity of MB onto KSBC much surpasses that of MB onto ASBC. These results indicate biomass pre-treatment is a cheap and convenient method to prepare biochars with unique physicochemical and adsorptive properties.