Effect of Cd(II) adsorption onto rice roots on its uptake by different indica and japonica rice varieties and toxicity effect of Cd(II) under acidic conditions.

The rapid increase in soil acidity coupled with the deleterious effects of cadmium (Cd) toxicity had led to a decline in worldwide agricultural production. Rice absorbs and accumulates Cd(II) from polluted paddy soils, increasing human health risks throughout the food chain. A 35-day hydroponic experiment with four japonica and four indica (two each of them tolerant and sensitive cultivars) was conducted in this study to investigate the adsorption and absorption of Cd(II) by rice roots as related with surface chemical properties of the roots. The results showed that the three chemical forms of exchangeable, complexed, and precipitated Cd(II) increased with the increase in Cd(II) concentration for all rice cultivars. The roots of indica rice cultivars carried more negative charges and had greater functional groups and thus adsorbed more exchangeable and complexed Cd(II) than those of japonica rice cultivars. This led to more absorption of Cd(II) by the roots and greater toxicity of Cd(II) to the roots of indica rice cultivars and more inhibition of Cd(II) stress on the growth of the roots and whole plants of indica rice cultivars compared with japonica rice cultivars, which was one of the main reasons for more declines in the biomass and length of indica rice roots and shoots than japonica rice cultivars. Cd(II) stress showed more toxicity to the sensitive rice cultivars and thus greater inhibition on the growth of the cultivars due to more exchangeable and complexed Cd(II) adsorbed by their roots induced by more negative charges and functional groups on the roots compared with tolerant rice cultivar for both indica and japonica, which resulted in greater decreases in the biomass and length of roots and shoots as well as chlorophyll contents of the sensitive cultivars than the tolerant cultivars. The roots of sensitive rice cultivars also absorbed more Cd(II) than tolerant rice cultivars due to the same reasons as above. These findings will provide useful references for the safe utilization and health risk prevention of Cd-contaminated paddy fields.

Constructing a "micro-nano collaboration" network via disk-milling: Value-enhanced utilization of flexible temperature-resistant cellulose insulation films.

Cellulose is a sustainable natural polymer material that has found widespread application in transformers and other power equipment because of its excellent electrical and mechanical performance. However, the utility of cellulose materials has been limited by the challenge of balancing heat resistance with flexibility. On the basis of the preliminary research conducted by the research team, further proposals have been put forward for a method involving disk milling to create a "micro-nanocollaboration" network for the fabrication of flexible, high-temperature-resistant, and ultrafine fiber-based cellulose insulating films. The resulting full-component cellulose films exhibited impressive properties, including high tensile strength (22 MPa), flexibility (92-263 mN), remarkable electrical breakdown strength (39 KV/mm), and volume resistivity that meets the standards for insulation materials (4.92 × 1011 Ω·m). These results demonstrate that the proposed method can produce full-component cellulose insulation films that offer both exceptional flexibility and high-temperature resistance.

Different Responses of Bacteria and Archaea to Environmental Variables in Brines of the Mahai Potash Mine, Qinghai-Tibet Plateau.

Salt mines feature both autochthonous and allochthonous microbial communities introduced by industrialization. It is important to generate the information on the diversity of the microbial communities present in the salt mines and how they are shaped by the environment representing ecological diversification. Brine from Mahai potash mine (Qianghai, China), an extreme hypersaline environment, is used to produce potash salts for hundreds of millions of people. However, halophiles preserved in this niche during deposition are still unknown. In this study, using high-throughput 16S rRNA gene amplicon sequencing and estimation of physicochemical variables, we examined brine samples collected from locations with the gradient of industrial activity intensity and discrete hydrochemical compositions in the Mahai potash mine. Our findings revealed a highly diverse bacterial community, mainly composed of Pseudomonadota in the hypersaline brines from the industrial area, whereas in the natural brine collected from the upstream Mahai salt lake, most of the 16S rRNA gene reads were assigned to Bacteroidota. Halobacteria and halophilic methanogens dominated archaeal populations. Furthermore, we discovered that in the Mahai potash mining area, bacterial communities tended to respond to anthropogenic influences. In contrast, archaeal diversity and compositions were primarily shaped by the chemical properties of the hypersaline brines. Conspicuously, distinct methanogenic communities were discovered in sets of samples with varying ionic compositions, indicating their strong sensitivity to the brine hydrochemical alterations. Our findings provide the first taxonomic snapshot of microbial communities from the Mahai potash mine and reveal the different responses of bacteria and archaea to environmental variations in this high-altitude aquatic ecosystem.

Electrochemical properties of roots determine antibiotic adsorption on roots.

The adsorption behaviors and transfer pathways of antibiotics in plant-soil system are greatly influenced by the electrochemical properties of both soil particles and plant roots. However, the effects of roots electrochemical properties on antibiotic adsorption are largely unknown. Here, the fresh soybean, maize, and wheat roots with different electrochemical properties were obtained from hydroponic cultivation, and the adsorption processes and mechanisms of doxycycline, tetracycline, sulfadiazine, and norfloxacin on roots under various environmental conditions were investigated. Results showed that the adsorption amount of antibiotics on roots increased with the initial concentration of antibiotics. The coexisting low-molecular weight organic acids and anions inhibited the antibiotic adsorption on roots. The soybean roots performed strong adsorption ability compared with the maize and wheat roots driven by the variations in root electrochemical properties. This study demonstrates the significance of electrochemical interactions between antibiotics and roots in plant-soil system and can contribute to the more accurate risk assessment and effective pollution control of antibiotics.

More negative charges on roots enhanced manganese(II) uptake in leguminous and non-leguminous poaceae crops.

BACKGROUND: Manganese (Mn) is an essential micronutrient for plants, whereas excess Mn(II) in soils leads to its toxicity to crops. Mn(II) is adsorbed onto plant roots from soil solution and then absorbed by plants. Root charge characteristics should affect Mn(II) toxicity to crops and Mn(II) uptake by the roots of the crops. However, the differences in the effects of root surface charge on the uptake of Mn(II) among various crop species are not well understood. RESULTS: The roots of nine legumes and six non-legume poaceae were obtained by hydroponics and the streaming potential method and spectroscopic analysis were used to measure the zeta potentials and functional groups on the roots, respectively. The results indicate that the exchangeable Mn(II) adsorbed by plant roots was significantly positively correlated with the Mn(II) accumulated in plant shoots. Legume roots carried more negative charges and functional groups than non-legume poaceae roots, which was responsible for the larger amounts of exchangeable Mn(II) on legume roots in 2 h and the Mn(II) accumulated in their shoots in 48 h. Coexisting cations, such as Ca2+ and Mg2+ , were most effective in decreasing Mn(II) taken up by roots and accumulated in shoots than K+ and Na+ . This was because Ca2+ and Mg2+ could compete with Mn(II) for active sites on plant roots more strongly compared to K+ and Na+ . CONCLUSION: The root surface charge and functional groups are two important factors influencing Mn(II) uptake by roots and accumulation in plant shoots. © 2023 Society of Chemical Industry.

Integration of transcriptomics and metabonomics revealed the protective effects of hemp seed oil against methionine-choline-deficient diet-induced non-alcoholic steatohepatitis in mice.

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease with few therapeutic options available currently. Hemp seed oil extracted from the seeds of hemp (Cannabis sativa L.) has significant nutritional and biological properties due to the unique composition of polyunsaturated fatty acids and various antioxidant compounds. However, little is known about the beneficial effects and molecular mechanisms of hemp seed oil on NASH. Here, the hepatoprotective effects of hemp seed oil on methionine-choline-deficient (MCD) diet-induced NASH in C57BL/6 mice were explored via integration of transcriptomics and metabolomics. Hemp seed oil could improve hepatic steatosis, inflammation and fibrosis in mice with MCD diet-induced NASH. In a nuclear magnetic resonance (NMR)-based metabonomic study, the hepatic and urinary metabolic profiles of mice supplemented with hemp seed oil showed a tendency to recover to healthy controls compared to those of NASH mice. Eight potential biomarkers associated with NASH in both liver tissue and urine were restored to near normal levels by administration of hemp seed oil. The proposed pathways were mainly involved in pyrimidine metabolism, one-carbon metabolism, amino acid metabolism, glycolysis and the tricarboxylic acid (TCA) cycle. Hepatic transcriptomics based on Illumina RNA-Seq sequencing showed that hemp seed oil exerted anti-NASH activities by regulating multiple signaling pathways, e.g., downregulation of the TNF signaling pathway, the IL-17 signaling pathway, the MAPK signaling pathway and the NF-κB signaling pathway, which played a pivotal role in the pathogenesis of NASH. In particular, integration of metabonomic and transcriptomic results suggested that hemp seed oil could attenuate NASH-related liver fibrosis by inhibition of glutaminolysis. These results provided new insights into the hepatoprotective effects of hemp seed oil against MCD diet-induced NASH and hemp seed oil might have potential as an effective therapy for NASH.

Time series analysis revealed prognostic value of continuous nasopharyngeal SARS-CoV-2 nucleic acid quantification for COVID-19: A retrospective study of >3000 COVID-19 patients from 2 centers.

BACKGROUND: Early stratification of disease progression remains one of the major challenges towards the post-coronavirus disease 2019 (COVID-19) era. The clinical relevance of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid load is debated due to the heterogeneity in patients' underlying health conditions. We determined the prognostic value of nasopharyngeal viral load dynamic conversion for COVID-19. METHODS: The cycling threshold (Ct) values of 28,937 nasopharyngeal SARS-CoV-2 RT-PCRs were retrospectively collected from 3,364 COVID-19 patients during hospitalization and coordinated to the onset of disease progression. The ROC curve was utilized to determine the predictive performance of the rate of Ct value alteration between two consecutive RT-PCR runs within 48 h (ΔCt%) for disease transformation across patients with different COVID-19 severity and immune backgrounds, and further validated with 1,860 SARS-CoV-2 RT-PCR results from an independent validation cohort of 262 patients. For the 67 patients with severe COVID-19, Kaplan-Meier analysis was performed to evaluate the difference in survival between patients stratified by the magnitude of Ct value alteration between the late and early stages of hospitalization. RESULTS: The kinetics of viral nucleic acid conversion diversified across COVID-19 patients with different clinical characteristics and disease severities. The ΔCt% is a clinical characteristic- and host immune status-independent indicator for COVID-19 progression prediction (AUC = 0.79, 95 % CI = 0.76 to 0.81), which outperformed the canonical blood test markers, including c-reactive protein (AUC = 0.57, 95 % CI = 0.53 to 0.61), serum amyloid A (AUC = 0.61, 95 % CI = 0.54 to 0.68), lactate dehydrogenase (AUC = 0.61, 95 % CI = 0.56 to 0.67), d-dimer (AUC = 0.56, 95 % CI = 0.46 to 0.66), and lymphocyte count (AUC = 0.62, 95 % CI = 0.58 to 0.66). Patients with persistent high SARS-CoV-2 viral load (an increase of mean Ct value < 50 %) during the first 3 days of hospitalization demonstrated a significantly unfavorable survival (HR = 0.16, 95 % CI = 0.04 to 0.65, P = 2.41 × 10-3). CONCLUSIONS: Viral nucleic acid dynamics of SARS-CoV-2 eliminates the inter-patient variance of basic health conditions and therefore, can serve as a prognostic marker for COVID-19.

The important role of surface hydroxyl groups in aluminum activation during phyllosilicate mineral acidification.

Phyllosilicate minerals are the important components in soils and an important source of activated aluminum (Al) during soil acidification. However, the mechanisms for Al activation in phyllosilicate minerals were not understood well. In this paper, the effect of phyllosilicate surface hydroxyl groups on Al activation during acidification was studied after the minerals were modified with inorganic and organic materials. After modification of kaolinite, montmorillonite, and illite with fulvic acid (FA-), iron oxide (Fe-), Fe combined with FA (Fe-FA-), and siloxane (Si-O-), the interlayer spaces were altered. For instance, when modified with Fe, Fe entered the interlayer spaces of kaolinite and montmorillonite and changed the interlayer spaces of both minerals but did not affect that of illite. Also, the other modification methods had significant effects on the interlayer space of montmorillonite but not on kaolinite and illite. It was observed that all the modification strategies inhibited Al activation during acidification by reducing the number of hydroxyl groups on the mineral surfaces and inhibiting protonation reactions between H+ and hydroxyl groups. Nevertheless, the inhibition effect varies with the type of phyllosilicate mineral. For kaolinite (Kao), the inhibition effect of the different modification methods on Al activation during acidification followed: Fe-FA-Kao > Fe-Kao > Si-O-Kao > FA-Kao. Additionally, for montmorillonite (Mon), the inhibition effect was in the order: Si-O-Mon > Fe-Mon > Fe-FA-Mon > FA-Mon, while for illite, it was: Fe-illite > Si-O-illite ≈ Fe-FA-illite > FA-illite. Thus, the hydroxyl groups on the surfaces and edges of phyllosilicate minerals play an important role in the activation of Al from the mineral structure. Also, the protonation of hydroxyl groups may be the first step during Al activation in these minerals. The results of this study can serve as a reference for the development of new technologies to inhibit soil acidification and Al activation.

Application of ultrasensitive assay for SARS-CoV-2 antigen in nasopharynx in the management of COVID-19 patients with comorbidities during the peak of 2022 Shanghai epidemics in a tertiary hospital.

OBJECTIVES: Various comorbidities associated with COVID-19 add up in severity of the disease and obviously prolonged the time for viral clearance. This study investigated a novel ultrasensitive MAGLUMI® SARS-CoV-2 Ag chemiluminescent immunoassay assay (MAG-CLIA) for diagnosis and monitoring the infectivity of COVID-19 patients with comorbid conditions during the pandemic of 2022 Shanghai. METHODS: Analytical performances of the MAG-CLIA were evaluated, including precision, limit of quantitation, linearity and specificity. Nasopharyngeal specimens from 232 hospitalized patients who were SARS-CoV-2 RT-qPCR positive and from 477 healthy donors were included. The longitudinal studies were performed by monitoring antigen concentrations alongside with RT-qPCR results in 14 COVID-19 comorbid participants for up to 22 days. The critical antigen concentration in determining virus infectivity was evaluated at the reference cycle threshold (Ct) of 35. RESULTS: COVID-19 patients were well-identified using an optimal threshold of 0.64 ng/L antigen concentration, with sensitivity and specificity of 95.7% (95% CI: 92.2-97.9%) and 98.3% (95% CI: 96.7-99.3%), respectively, while the Wondfo LFT exhibited those of 34.9% (95% CI: 28.8-41.4%) and 100% (95% CI: 99.23-100%), respectively. The sensitivity of MAG-CLIA remained 91.46% (95% CI: 83.14-95.8%) for the samples with Ct values between 35 and 40. Close dynamic consistence was observed between MAG-CLIA and viral load time series in the longitudinal studies. The critical value of 8.82 ng/L antigen showed adequate sensitivity and specificity in evaluating the infectivity of hospitalized convalescent patients with comorbidities. CONCLUSIONS: The MAG-CLIA SARS-CoV-2 Ag detection is an effective and alternative approach for rapid diagnosis and enables us to evaluate the infectivity of hospitalized convalescent patients with comorbidities.

Green production of lignocellulose nanofibrils by FeCl3-catalyzed ethanol treatment.

The traditional strategy for isolating cellulose nanomaterials requires various chemicals and a high energy input, while achieving a low product yield owing to lignin removal during pulping and bleaching. Here, we propose a green ethanol pretreatment process with a synergistic effect using ultrasound and FeCl3 to produce lignocellulose nanofibrils (LCNF) with a high yield (over 67 %) from thermomechanical pulp. Notably, a high-aspect-ratio LCNF with uniformly distributed lignin nanoparticles, a high lignin content, and excellent thermostability (Tmax > 330 °C) with a typical cellulose I crystalline structure were successfully obtained. In addition, reduced distillation can easily retrieve the FeCl3 solution and ethanol, reducing reagent waste. In general, FeCl3-catalyzed ethanol pretreatment can serve as a sustainable and environmentally friendly approach for converting sustainable lignocelluloses into high value-added nanomaterials. Moreover, the obtained LCNF can be applied in diverse fields.

Microbial communities associated with thermogenic gas hydrate-bearing marine sediments in Qiongdongnan Basin, South China Sea.

Biogenic and thermogenic gas are two major contributors to gas hydrate formation. Methane hydrates from both origins may have critical impacts on the ecological properties of marine sediments. However, research on microbial diversity in thermogenic hydrate-containing sediments is limited. This study examined the prokaryotic diversity and distributions along a sediment core with a vertical distribution of thermogenic gas hydrates with different occurrences obtained from the Qiongdongnan Basin by Illumina sequencing of 16S rRNA genes as well as molecular and geochemical techniques. Here, we show that gas hydrate occurrence has substantial impacts on both microbial diversity and community composition. Compared to the hydrate-free zone, distinct microbiomes with significantly higher abundance and lower diversity were observed within the gas hydrate-containing layers. Gammaproteobacteria and Actinobacterota dominated the bacterial taxa in all collected samples, while archaeal communities shifted sharply along the vertical profile of sediment layers. A notable stratified distribution of anaerobic methanotrophs shaped by both geophysical and geochemical parameters was also determined. In addition, the hydrate-free zone hosted a large number of rare taxa that might perform a fermentative breakdown of proteins in the deep biosphere and probably respond to the hydrate formation.

Palliative radiotherapy combined with stent insertion to relieve dysphagia in advanced esophageal carcinoma patients: A systematic review and meta-analysis.

Introduction: Esophageal cancer is one of the most aggressive malignancies with limited treatment options, thus resulting in high morbidity and mortality. For patients with advanced esophageal cancer, the median survival is 3-6 months, with the majority requiring intervention for dysphagia. Objective: To compare the relief of dysphagia in patients with incurable esophageal cancer treated with stenting alone or a combination of stenting and palliative radiotherapy. Methods: The protocol of this study was pre-registered on PROSPERO (CRD42022337481). We searched PubMed, Wan Fang, Cochrane Library, Embase, and Web of Science databases. The literature search, quality assessment, and data extraction were conducted by two reviewers independently. The primary endpoints included median overall survival and dysphagia scores. Bleeding events, stent migration, and pain events were secondary outcomes. The meta-analysis results (the primary and secondary outcomes) were pooled by means of a random-effect model or a fixed-effects model. Results: Nine studies with a total of 851 patients were included in this meta-analysis, consisting of 412 patients in the stenting alone group and 439 patients in the palliative radiotherapy after esophageal cancer stenting (ROCS) group. The ROCS group could significantly improve dysphagia scores (SMD: -0.77; 95% CI: -1.02 to -0.51) and median overall survival (SMD: 1.70; 95% CI: 0.67-2.72). Moreover, there were no significant differences between the two groups in bleeding events, pain events, and stent migration. Conclusion: Patients with dysphagia in advanced esophageal cancer may benefit further from ROCS in median overall survival and dysphagia scores. However, there was no significant advantage in improving bleeding events, pain events, and stent migration. Therefore, it is urgent to find a better therapy to improve adverse events in the future. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42022337481.

Molecular Insights into the Effect of Nitrogen Bubbles on the Formation of Tetrahydrofuran Hydrates.

In this work, a molecular dynamics simulation was conducted to study the microscopic mechanism of how nitrogen bubbles affect the formation of THF hydrates at the molecular level. The results obtained reveal that the nitrogen bubble can promote the formation of THF hydrates. In the system with a nitrogen bubble, more THF-filled cages were generated, and the crystal structure was more orderly. The promotion of nitrogen bubbles on hydrate crystallization comes from the dissolution of nitrogen molecules. Some of dissolved nitrogen molecules can be enclosed in small hydrate cages near the nitrogen bubble, which can serve as stable sites for hydrate crystal growth, resulting in the fact that THF-filled cages connected with N2-filled cages are much more stable and have a long lifetime. The results in this work can help to understand the promotion effect of micro- and nano-air bubbles on the crystallization of THF hydrates.

Solvent-free preparation of thermoplastic bio-materials from microcrystalline cellulose (MCC) through reactive extrusion.

Cellulose, as a renewable biopolymer, was acknowledged as a promising alternative for petroleum polymer. However, the poor thermoplasticity of cellulose caused a limitation in its full development. Herein, a solvent-free and simple strategy was proposed for the preparation of thermoplastic bio-materials from microcrystalline cellulose (MCC). Kraft lignin (KL) was employed as a plasticizer in this work. It was demonstrated that MCC-based materials with great thermoplasticity and mechanical properties could be successfully prepared by reactive extrusion. The obtained MCC-based material ML8G (with 50 wt% KL adding) possessed great thermostability and thermoplastic properties with an obvious glass transition temperature (Tg) at 106 °C. In addition, the bending strength, flexural modulus and storage modulus of the MCC-based material were improved to 20.44 MPa, 3139.47 MPa and 5.81 GPa respectively. Furthermore, the obtained MCC-based material exhibited good water stability and biodegradability. The comprehensive results confirmed the feasibility of MCC-based materials plasticized with KL through reactive extrusion. Overall, this work was a promising development in the field of bio-plastic utilization of natural products from a green source.

Effects of the increases in soil pH and pH buffering capacity induced by crop residue biochars on available Cd contents in acidic paddy soils.

To explore the effects of the increases in pH and pH buffering capacity (pHBC) induced by crop residue biochars on the changes in soil available Cd content, six acidic paddy soils developed from different parents were amended with seeded sunflower plate biochar (SSPBC), peanut straw biochar (PSBC) and corn straw biochar (CSBC). The pH, pHBC, and available Cd of the soils were measured after laboratory incubation. The results showed that the incorporation of crop residue biochars led to the increases in soil pH and pHBC, but a decrease in soil available Cd content. The decreasing order of available Cd content was SSPBC > PSBC > CSBC and was consistent with the changes in soil pH induced by the biochars. During submerging and draining, soil pH increased first and then declined, however the content of available Cd decreased first and then increased significantly. Soil pH in the treatments with biochars showed little change during draining, which was different from the control without the biochars added. This was attributed to the enhancing effect of the biochars on soil pHBC. Also, there was a significant negative correlation between the change in available Cd content and soil pHBC during submerging/draining alternation and suggested that higher pHBC corresponded to smaller soil available Cd content. Consequently, the amount of Cd absorbed by rice was reduced, thereby reducing the potential risk of soil Cd to humans. These results can provide useful references for the remediation of Cd-contaminated paddy soils.

Geochemical Characteristics and Significance of Organic Matter in Hydrate-Bearing Sediments from Shenhu Area, South China Sea.

Rock-Eval pyrolysis and the biomarker composition of organic matter were systematically studied in hydrate-bearing sediments from the Shenhu area, South China Sea. The n-alkane distribution patterns revealed that the organic matter in the sediments appeared to originate from mixed sources of marine autochthonous input, terrestrial higher plants, and ancient reworked organic matter. The low total organic carbon contents (average < 0.5%) and the low hydrogen index (HI, <80 mg HC/g TOC) suggested the poor hydrocarbon-generation potential of the deposited organic matter at a surrounding temperature of <20 °C in unconsolidated sediments. The abnormally high production index and the fossil-originated unresolved complex mixture (UCM) accompanied by sterane and hopane of high maturity indicated the contribution of deep hydrocarbon reservoirs. Preliminary oil-to-source correlation for the extracts implied that the allochthonous hydrocarbons in the W01B and W02B sediments might have originated from the terrestrial source rocks of mature Enping and Wenchang formations, while those of W03B seem to be derived from more reduced and immature marine source rocks such as the Zhuhai formation. The results of the organic extracts supported the previous identification of source rocks based on the isotopic composition of C2+ hydrate-bound gases. The biomarker of methanogens, squalane, was recognized in the sediments of this study, possibly suggesting the generation of secondary microbial gases which are coupled with the biodegradation of the deep allochthonous hydrocarbons.

Effects of pH variations caused by redox reactions and pH buffering capacity on Cd(II) speciation in paddy soils during submerging/draining alternation.

Incubation experiments were conducted to investigate the influencing factors of pH variation in different paddy soils during submerging/draining alternation and the relationship between pH buffering capacity (pHBC) and Cd speciation in ten paddy soils developed from different parent materials (including 8 acid paddy soils and 2 alkaline paddy soils). The soil pHBC and the changes in soil pH, Eh, Fe2+, Mn2+, SO42- and Cd speciation were determined. The results showed that there was a significant positive correlation between cation exchange capacity (CEC) and pHBC of these paddy soils, indicating that soil CEC is a key factor affecting the pHBC of paddy soils. The contribution of Fe(III) oxide reduction to H+ consumption is far greater than the reduction of Mn(IV)/Mn(III) oxides and SO42- during the submerging. For example, the contribution of the reduction of manganese oxides, SO42- and iron oxides to H+ consumption in the paddy soils from Anthrosol at 15 d submerging was 1.2%, 11.6% and 87.2%, respectively. This confirms that the reduction of Fe(III) oxides plays a leading role in increasing soil pH. Importantly, we noticed that during submerging, soil pH was increased and resulted in the content of available Cd in soils being reduced. This was due to the transformation of Cd to less active forms. Also, there was a significant positive correlation between the change rate of available Cd, the percentage of acid extractable Cd and pH variation. This suggests that the variation in soil pH was responsible for the transformation of Cd speciation. In addition, the change rate of available Cd and the percentage of acid extractable Cd concentration were significantly negatively correlated with soil pHBC. The soil with higher pHBC experienced less pH change, and thus the change rate of available Cd and the percentage of acid extractable Cd concentration were less for the soil. The results of this study can provide a basis for the remediation of Cd-contaminated acidic paddy soils.

Cellulose nanofibrils (CNFs) in uniform diameter: Capturing the impact of carboxyl group on dispersion and Re-dispersion of CNFs suspensions.

The poor dispersibility and re-dispersibility of cellulose nanofibrils (CNFs) in various solvents and polymers have been recognized as the key factors limiting their potential applications. TEMPO oxidation, as the most common surface modification, can greatly improve the dispersion and re-dispersion of CNFs. However, the diameter of TEMPO-oxidized cellulose nanofibers (TOCNFs) has not been regulated in most researches, which was an important factor determining the dispersion and re-dispersion of TOCNFs. Herein, this work explored the effect of carboxyl groups on dispersion and re-dispersion of TOCNFs with uniform diameter in various solvents. Notably, fractal dimension was innovatively introduced to characterize the distribution of TOCNFs diameter. The fractal dimension and statistic diameter of TCONFs with different carboxyl group contents are ~1.56 and ~22 nm, demonstrating that the diameter of TOCNFs has been regulated in the same range. When the carboxyl group content is up to 1.58 mmol/g, the dispersion and re-dispersion of TOCNFs suspension in water and different organic solvents are the most uniform and stable. In a word, this work explores the dispersion and re-dispersion of TOCNFs with the uniform diameter and different carboxyl group contents, which can provide the theoretical guidance for various potential applications of nanofibrils in polymer matrix composites.

Crystal face dependent wettability of α-quartz: Elucidation by time-of-flight secondary ion mass spectrometry techniques combined with molecular dynamics.

HYPOTHESIS: Quartz is one of the most common but important minerals, and its wettability plays a significant role in affecting various natural and industrial processes. Studies have revealed that different crystal faces of quartz are with different wettabilities, but its mechanism is still vague. EXPERIMENTS AND SIMULATIONS: For specifying the mechanism of crystal face dependent wettability, the contact angles of three different liquids on the crystal faces of α-quartz are measured; the time-of-flight secondary ion mass spectrometry (ToF-SIMS) is employed to establish the crystal surface models; molecular dynamics (MD) simulations with the surface models are performed to understand the wetting behavior at molecular scale. FINDINGS: Based on the contact angle measurements, the wettabilities of different crystal faces of α-quartz are found different, which can be directly attributed to the concentration of hydroxyl group on crystal faces based on ToF-SIMS results. MD simulations yield consistent results with the contact angle order recognized from experiments, revealing that the surface hydroxyl group controls the wettability of α-quartz crystal faces. It is also recognized that the pristine surface atomic arrangement, especially the surface concentration of unsaturated bond (an intrinsic property of α-quartz), is the intrinsic cause of the difference in the concentration of hydroxyl group of the crystal surface.

Screw extrusion pretreatment for high-yield lignocellulose nanofibrils (LCNF) production from wood biomass and non-wood biomass.

To develop a facile and low-cost nanofibrils process with excellent feedstock adaptability, high-yield lignocellulose nanofibrils (LCNF) are produced directly from wood and non-wood biomass using glycerol solvent via screw extrusion pretreatment. Different LCNFs are obtained from four classical raw materials (polar, pine, bamboo, and wheat straw) in this research, followed by comparing their morphological, thermochemical, and mechanical properties. More than 70 wt% of LCNF could be obtained from low-cost substrates except for LCNF from wheat straw with 62.3 wt% yield. Besides, the morphology property of wood LCNF exhibit more uniform distribution over that of non-wood LCNF due to narrower size distribution. Strikingly, despite of the slightly lower LCNF crystallinity various from 52.4% to 62.6% obtained from four substrates, all the LCNFs separated from wood and non-wood biomass exhibit high thermal stability (Tmax over 330 °C), which is higher than conventional nanocellulose, indicating that the crystal area could be well maintained during the pretreated process. Moreover, all the LCNF films show excellent tensile strength which is close to nanocellulose materials. Besides, the Young's modulus of wood-based LCNF films is higher than that of non-wood based LCNF films. Overall, LCNF with excellent performance could be achieved from low-cost biomass by our facile process, which provides a feasible route for industrial production of bio-based nanofilms.