Temporal trends in the visual impairment burden attributable to high fasting plasma glucose levels: a population-based study.

AIMS: Elevated fasting plasma glucose (FPG) levels have been associated with visual impairment. Recognising global patterns of high FPG level exposure can facilitate the prevention and treatment of related visual impairment. We aimed to assess the trends of the visual impairment burden attributable to high FPG levels globally, regionally, nationally, and by income level. METHODS: We obtained data on the visual impairment burden attributable to high FPG levels from the Global Burden of Disease Study 2019. We evaluated the trends of related disability-adjusted life-years (DALYs) from 1990 to 2019 through joinpoint regression analysis and calculated the annual percentage change (APC) and average APC (AAPC). Countries/territories were categorised into high-, upper-middle-, lower-middle-, and low-income groups based on the 2019 World Bank criteria. RESULTS: The age-standardised rate of DALYs due to visual impairment attributable to high FPG levels significantly increased globally, from 6.75 (95% uncertainty interval [UI], 1.55-15.79) in 1990 to 8.44 per 100,000 population (95% UI, 2.00-19.63) in 2019 (AAPC, 0.79; 95% confidence interval [CI], 0.69-0.89; p < 0.001). The largest increases were observed in high-income (AAPC, 0.73; 95% CI, 0.60-0.85) and lower-middle-income countries/territories (AAPC, 0.68; 95% CI, 0.62-0.73). In 2019, lower-middle-income countries/territories had the highest age-standardised DALY rate (18.94 per 100,000 population; 95% UI, 4.39-43.98), whereas high-income countries/territories had the lowest (2.97 per 100,000 population; 95% UI, 0.75-6.74). CONCLUSIONS: The visual impairment burden associated with elevated FPG levels has increased significantly, necessitating enhanced public health prevention measures, clinical management, and treatment to mitigate adverse outcomes.

Metabolomics unveil key pathways underlying the synergistic activities of aztreonam and avibactam against multidrug-resistant Escherichia coli.

PURPOSE: Aztreonam/avibactam is effective against serious infections caused by Gram-negative bacteria including Enterobacterales harboring metallo-ß-lactamases. While the utility of this combination has been established in vitro and in clinical trials, the purpose of this study is to enhance our understanding of the underlying mechanism responsible for their activities through metabolomic profiling of a multidrug-resistant Escherichia coli clinical isolate. METHODS: Metabolomic analyses of time-dependent changes in endogenous bacterial metabolites in a clinical isolate of a multidrug-resistant E. coli treated with aztreonam and avibactam were performed. E. coli metabolomes were compared at 15 min, 1 h and 24 h following treatments with either avibactam (4 mg/L), aztreonam (4 mg/L), or aztreonam (4 mg/L) + avibactam (4 mg/L). RESULTS: Drug treatment affected 326 metabolites with magnitude changes of at least 2-fold, most of which are involved primarily in peptidoglycan biosynthesis, nucleotide metabolism, and lipid metabolism. The feedstocks for peptidoglycan synthesis were depleted by aztreonam/avibactam combination; a significant downstream increase in nucleotide metabolites and a release of lipids were observed at the three timepoints. CONCLUSION: The findings indicate that the aztreonam/avibactam combination accelerates structural damage to the bacterial membrane structure and their actions were immediate and sustained compared to aztreonam or avibactam alone. By inhibiting the production of crucial cell wall precursors, the combination may have inflicted damages on bacterial DNA.

Senolytic and senomorphic agent procyanidin C1 alleviates structural and functional decline in the aged retina.

Increased cellular senescence burden contributes in part to age-related organ dysfunction and pathologies. In our study, using mouse models of natural aging, we observed structural and functional decline in the aged retina, which was accompanied by the accumulation of senescent cells and senescence-associated secretory phenotype factors. We further validated the senolytic and senomorphic properties of procyanidin C1 (PCC1) both in vitro and in vivo, the long-term treatment of which ameliorated age-related retinal impairment. Through high-throughput single-cell RNA sequencing (scRNA-seq), we comprehensively characterized the retinal landscape after PCC1 administration and deciphered the molecular basis underlying the senescence burden increment and elimination. By exploring the scRNA-seq database of age-related retinal disorders, we revealed the role of cellular senescence and the therapeutic potential of PCC1 in these pathologies. Overall, these results indicate the therapeutic effects of PCC1 on the aged retina and its potential use for treating age-related retinal disorders.

Quantitative Assessment of Fundus Tessellated Density in Highly Myopic Glaucoma Using Deep Learning.

Purpose: To characterize the fundus tessellated density (FTD) in highly myopic glaucoma (HMG) and high myopia (HM) for discovering early signs and diagnostic markers. Methods: This retrospective cross-sectional study included hospital in-patients with HM (133 eyes) and HMG (73 eyes) with an axial length ≥26 mm at Zhongshan Ophthalmic Center. Using deep learning, FTD was quantified as the average exposed choroid area per unit area on fundus photographs in the global, macular, and disc regions. FTD-associated factors were assessed using partial correlation. Diagnostic efficacy was analyzed using the area under the curve (AUC). Results: HMG patients had lower global (0.20 ± 0.12 versus 0.36 ± 0.09) and macular FTD (0.25 ± 0.14 vs. 0.40 ± 0.09) but larger disc FTD (0.24 ± 0.11 vs. 0.19 ± 0.07) than HM patients in the tessellated fundus (all P < 0.001). In the macular region, nasal FTD was lowest in the HM (0.26 ± 0.13) but highest in the HMG (0.32 ± 0.13) compared with the superior, inferior, and temporal subregions (all P < 0.05). A fundus with a macular region nasal/temporal (NT) FTD ratio > 0.96 (AUC = 0.909) was 15.7 times more indicative of HMG than HM. A higher macular region NT ratio with a lower horizontal parapapillary atrophy/disc ratio indicated a higher possibility of HMG than HM (AUC = 0.932). Conclusions: FTD differs in degree and distribution between HMG and HM. A higher macular NT alone or with a lower horizontal parapapillary atrophy/disc ratio may help differentiate HMG. Translational Relevance: Deep learning-based FTD measurement could potentially assist glaucoma diagnosis in HM.

[Effects of Land Use Change on Soil Aggregate Stability and Soil Aggregate Organic Carbon in Karst Area of Southwest China].

Investigating the relationship of soil aggregate stability with the organic carbon in the aggregate and its response to land use change is conducive to the estimation of soil carbon sink potential, improvement of rocky desertification, and rational land use in karst areas of Southwest China. In order to explore the effects of land use change on the composition and stability of soil aggregate stability as well as the content of aggregate organic carbon, the soil (0-30 cm) of five land use types (secondary forest, pomelo forest, paddy field, pepper forest, and dry land) was selected as the research object. The characteristics and correlation of soil aggregate components and organic carbon under different land use patterns were obtained, and the contribution of soil aggregates to the change in organic carbon after land use change was calculated. The results showed that the macroaggregates in the surface soil (0-15 cm) of the secondary forest, pomelo forest, and paddy field were 63.32%, 52.38%, and 47.77%, respectively, which were significantly higher than that of dry land (23.70%), as was also seen in the lower layer (15-30 cm). The geometric mean diameter (GMD) and mean weight diameter (MWD) of soil aggregates in the secondary forest, pomelo forest, and paddy field were significantly higher than those in dry land. In the surface soil, the organic carbon of the secondary forest and paddy field was significantly higher than that of other land use patterns. By contrast, in the lower soil layer, only the organic carbon of the paddy field was significantly higher than that of the others. Under different land use patterns, the organic carbon content of aggregates followed the same order of macroaggregates > microaggregates > silt and clay, indicating that macroaggregates allowed soil organic carbon to accumulate, whereas silt and clay did the opposite. According to correlation analysis, the content of soil macroaggregates was significantly positively correlated with GMD, MWD, and soil aggregate organic carbon, suggesting that the increase in soil macroaggregates could improve the stability of soil aggregates and store more soil organic carbon. Further, as land use change may have significantly affected the soil aggregate, moderate development of forestry and paddy cultivation is suggested to improve the soil carbon sequestration potential in the karst area of Southwest China.

Age-period-cohort analysis of the global burden of visual impairment according to major causes: an analysis of the Global Burden of Disease Study 2019.

BACKGROUND: Cataract, glaucoma and age-related macular degeneration (AMD) are major causes of visual impairment. As these are age-related conditions, the prevalence of associated visual impairment is anticipated to increase as the population ages. However, age-period-cohort effects on the disease burden have not been investigated. METHODS: This was a population-based study using aggregated data from the Global Burden of Disease Study 2019. Age-period-cohort analysis was conducted using age-standardised prevalence rates (ASPRs) of visual impairment caused by cataract, glaucoma and AMD as disease burden indicator. RESULTS: In 2019, the estimated global ASPRs of visual impairment due to cataract, glaucoma and AMD were 1207.9, 94.7 and 96.8 per 100 000 people, respectively. Between 1990 and 2019, the global visual impairment ASPRs for glaucoma and AMD declined by 15.4% and 2.0%, respectively, whereas that for cataract increased by 5.0%. Wide heterogeneity was observed in age-period-cohort effects on ASPRs across different Sociodemographic Index (SDI) regions. Low-middle SDI regions had the largest ASPR reductions for all three eye diseases and showed improvement in both period and cohort effects. In contrast, in high-middle SDI regions, visual impairment ASPRs significantly increased during the study period with unfavourable patterns. CONCLUSIONS: The wide heterogeneity in age-period-cohort effects reflects different stages of societal transition and vision health. The unfavourable trends in age-period-cohort effects on disease prevalence identified in specific groups provide key information that may be used to identify priority groups in need of treatment and prevention.

Visual impairment burden in retinopathy of prematurity: trends, inequalities, and improvement gaps.

Retinopathy of prematurity (ROP) is an important cause of avoidable childhood visual impairment, and the increase in number and survival of premature infants may inflate its burden globally. We aimed to comprehensively assess the trends and inequalities in the burden of ROP-related visual impairment and to identify improvement gaps to facilitate appropriate actions in neonatal care systems. We obtained ROP data from the Global Burden of Disease 2019 study. We employed joinpoint regression analysis to assess the trends of the burden of ROP-related visual impairment, measured by age-standardised prevalence rates, health equity analysis methods to evaluate cross-country burden inequalities, and data envelopment and stochastic frontier analyses to identify improvement gaps based on the development status, i.e., sociodemographic index (SDI). Between 1990 and 2019, the age-standardised prevalence rates of ROP-related visual impairment significantly increased worldwide (average annual percentage change: 0.23 [95% confidence interval, 0.21-0.26] among males and 0.26 [0.25-0.27] among females), primarily in developed regions. Although significant SDI-related cross-country inequalities were identified, these reduced over time (slope index of inequality: -57.74 [-66.22 to -49.25] in 1990 to -29.68 [-38.39 to -20.97] in 2019; health concentration index: -0.11 [-0.13 to -0.09] in 1990 to -0.07 [-0.09 to -0.06] in 2019). Notably, some less-developed countries exhibited superior performance despite limited resources, whereas others with a higher SDI delivered lagging performance.  Conclusion: The global burden of ROP-related visual impairment has steadily increased between 1990 and 2019, with disproportionate burden concentration among less-developed countries, requiring appropriate preventive and intervention measures. What is Known: • Retinopathy of prematurity (ROP) is an important cause of avoidable childhood visual impairment. • The prevalence of ROP is anticipated to increase due to the growing number of extremely premature infants. What is New: • The prevalence of ROP-related visual impairment has increased worldwide, primarily in developed regions, with declining but persisting cross-country inequalities. • The increasing burden of ROP-related visual impairment should be considered as part of global and national health agendas, requiring interventions with proven efficacy.

[Effect of Land Use on the Stability of Soil Organic Carbon in a Karst Region].

The composition of soil organic carbon and its stability mechanism are the key to understanding the terrestrial carbon sink capacity. The stability of soil organic carbon in a karst ecosystem greatly affects the soil carbon fixation capacity. In order to understand the impact of human activities on the stability of soil organic carbon in karst areas, the karst valley area of Zhongliang Mountain in Chongqing was selected as an example, and soil samples of four typical land use modes (mixed forest, bamboo forest, grassland, and cultivated land) were collected in layers to analyze the total organic carbon (TOC) and heavy fraction organic carbon (HFOC). The distribution characteristics of light fraction organic carbon (LFOC), labile organic carbon (LOC), and recalcitrant organic carbon (ROC) were analyzed quantitatively by using a structural equation model to provide basic data for soil carbon sink assessment and soil quality protection in karst areas. The results showed that the organic carbon components under different land use patterns in karst areas had obvious surface accumulation, and the content of organic carbon components in the surface layer was 1.2 times that in the bottom layer. Except for LFOC, the content of other organic carbon components was the highest in the mixed forest, followed by that in the bamboo forest and wasteland, with the lowest in cultivated land. Mixed forest ω(TOC) content was the highest, 42.5 g·kg-1, followed by that of bamboo forest (36.6 g·kg-1) and grassland (18.7 g·kg-1), and cultivated land content was the lowest, 13.4 g·kg-1. The soil organic carbon content of cultivated land was 68.5%, 63.5%, and 28.3% lower than that of mixed forest, bamboo forest, and grassland, respectively. Mixed forest had the highest content of ω(HFOC), 21 g·kg-1, followed by those of bamboo forest (20.9 g·kg-1), grassland (18.2 g·kg-1), and cultivated land (13.5 g·kg-1). The mixed forest ω(LOC) content was the highest, 16.3 g·kg-1, followed by those of bamboo forest (14.9 g·kg-1), grassland (11.5 g·kg-1), and cultivated land (5.3 g·kg-1). Mixed forest ω (ROC) content was the highest, 25.7 g·kg-1, followed by those of bamboo forest (21.6 g·kg-1), grassland (15.9 g·kg-1), and cultivated land (10.3 g·kg-1). The bamboo forest land ω(LFOC) content was 15.9 g·kg-1, followed by those of mixed forest (13.9 g·kg-1), grassland (7.3 g·kg-1), and cultivated land (4.9 g·kg-1). The recalcitrant organic carbon index (ROCI) was used to indicate the stability of soil organic carbon. The variation range of ROCI was 33.9%-64.5%, of which the highest was mixed forest (64.5%-66.3%), and the lowest was cultivated land (33.8%-39.6%). The ROCI of mixed forest, bamboo forest, and grassland were 1.8 times, 1.6 times, and 1.4 times that of cultivated land, respectively. Karst area ω (inert organic carbon) content and ROCI showed that human agricultural activities caused the reduction in soil organic carbon content and the destruction of soil physical structure, resulting in the accelerated decomposition and turnover rate of soil organic matter. The most important factor affecting soil stability in karst areas was soil pH. Tillage activities caused soil pH to rise, reduced soil microbial activity, and were not conducive to the accumulation of the inert organic carbon and soil organic carbon pool in the soil.

Global, Regional, and National Epidemiology of Visual Impairment in Working-Age Individuals, 1990-2019.

Importance: Visual impairment in working-age individuals can affect their general health and employment prospects, leading to decreased social and economic productivity and increased poverty rates. Nonetheless, investigations in this population appear to be limited. Objective: To investigate the trends of visual impairment prevalence and disability-adjusted life-years (DALYs) in working-age individuals from 1990 to 2019. Design, Setting, and Participants: This cross-sectional, population-based study used data for individuals of working age (15-64 years) from 204 countries and territories obtained from the Global Burden of Disease 2019 study. The data analysis was performed between May 1 and 10, 2023. Exposure: Visual impairment, defined as visual acuity of less than 6/18 (20/60) or near visual acuity of less than 6/12 (20/40) distance equivalent as determined by Snellen chart. Main Outcomes and Measures: Trends of visual impairment prevalence, DALYs, and corresponding estimated annual percent changes (EAPCs) from 1990 to 2019 were stratified according to region, nation, and sociodemographic index (SDI). Results: There were 437 539 484 (95% uncertainty interval [UI], 325 463 851-575 573 588) prevalent cases of visual impairment globally (53.12% female and 46.88% male) in 2019, representing an increase of 91.46% from 1990 (prevalent cases, 228 530 964; 95% UI, 172 515 833-297 118 596). Over 3 decades, visual impairment-associated DALYs increased from 7 601 852 (95% UI, 5 047 030-11 107 897) to 12 563 276 (95% UI, 8 278 866-18 961 723). Among the 5 SDI groups, the low-SDI group had the largest increase in DALYs (898 167 [95% UI, 597 161-1 301 931] in 1990 to 1 634 122 [95% UI, 1 079 102-2 444 381] in 2019). Regionally, the greatest increase in prevalence was observed in Eastern Europe (EAPC, 0.10; 95% CI, 0.02-0.19). Among all countries and territories, Nepal had the highest national prevalence of visual impairment per 100 000 population in 2019 (26 008.45; 95% UI, 19 987.35-32 482.09), while South Sudan had the highest DALY rate per 100 000 population (480.59; 95% UI, 316.06-697.06). Conclusions and Relevance: Despite the mild decrease in visual impairment prevalence rates in less-developed countries, these findings suggest that the number of prevalent cases globally has increased substantially, with discernible unfavorable patterns in developed regions. The findings support the notion that visual impairment in working-age individuals is a growing global health challenge. A better understanding of its epidemiology may facilitate the development of appropriate measures for prevention and treatment from both medical and social perspectives.

Temporal trends and projection of blindness and vision loss prevalence in older adults in BRICS countries.

BACKGROUND: Blindness and vision loss (BVL) is a major global health issue affecting older adults, but its burden in transition countries has received limited attention. Therefore, we aimed to assess the trends in the burden of BVL among older adults between 1990 and 2019 across Brazil, Russia, India, China, and South Africa (BRICS), and predict the burden by 2040. METHODS: Data on BVL and its related causes were obtained from the Global Burden of Disease 2019 study. We investigated the temporal trends by calculating the average annual percentage change using joinpoint regression analysis. Subsequently, we performed Bayesian age-period-cohort modeling to estimate the burden of BVL and its related causes by 2040. RESULTS: Most BRICS countries experienced a significant decline (p < 0.05) in age-standardized prevalence rates, and the decreasing trends tend to continue. However, by 2040, the number of BVL cases is expected to increase by approximately 50% across BRICS, with an estimated approximately 192, 170, 25, 17, and 7 million cases in China, India, Russia, Brazil, and South Africa, respectively. The related ranks of BVL causes are also estimated to change in the future, particularly in India. CONCLUSIONS: The different burdens and trends of BVL across BRICS reflected the different stages of population health transition. Effective eye disease prevention requires appropriate public health interventions. Developing effective health policies and services for older adults is urgently needed in BRICS countries.

Metabolomics reveals the mechanism of action of meropenem and amikacin combined in the treatment of Pseudomonas aeruginosa.

The treatment of Pseudomonas aeruginosa infection often involves the combined use of ß-lactam and aminoglycoside antibiotics. In this study, we employed metabolomic analysis to investigate the mechanism responsible for the synergistic activities of meropenem/amikacin combination therapy against multidrug-resistant P. aeruginosa strains harboring OXA-50 and PAO genes. Antibiotic concentrations for meropenem (2 mg/L) monotherapy, amikacin (16 mg/L) monotherapy, and meropenem/amikacin (2/16 mg/L) combination therapy were selected based on clinical breakpoint considerations. Metabolomic analysis revealed significant alterations in relevant metabolites involved in bacterial cell membrane and cell wall synthesis within 15 min of combined drug administration. These alterations encompassed various metabolic pathways, including fatty acid metabolism, peptidoglycan synthesis, and lipopolysaccharide metabolism. Furthermore, at 1 h and 4 h, the combination therapy exhibited significant interference with amino acid metabolism, nucleotide metabolism, and central carbon metabolism pathways, including the tricarboxylic acid cycle and pentose phosphate pathway. In contrast, the substances affected by single drug administration at 1 h and 4 h demonstrated a noticeable reduction. Meropenem/amikacin combination resulted in notable perturbations of metabolic pathways essential for survival of P. aeruginosa, whereas monotherapies had comparatively diminished impacts.

Internal reuse of methanol-to-olefin wastewater based on micro-channel separation coupling hydrocyclone regeneration.

Methanol-to-olefin (MTO) is a typical new coal chemical industry example. Due to the large volume of generated wastewater, complex composition including catalysts, aromatics and various oxygen-containing compounds, and serious environmental hazard, wastewater recycling is critical for sustainable industrial development and ecological protection. Herein, a swirl regenerating micro-channel separation (SRMS) technology was proposed to integrate deep filtration and hydrocyclone-enhanced regeneration. A small-scale experimental investigation was first conducted to verify the feasibility of the MTO wastewater treatment. A pilot SRMS device with a treatment capacity of 20 m3/h was constructed, and the device's continuous operation effect and stability were comprehensively evaluated. The separation performance of the SRMS device at different solution pH values and the impact of the hydrocyclone-enhanced regeneration of separation media were discussed in detail. At low solution pH values (<7), the SRMS device exhibits an average separation efficiency of 92.0% for fine particulate matter in wastewater, and the median particle size, d50, decreases from 1.55 to 0.6 µm. As the solution pH increases, the repulsive energy barrier for the medium-contaminant and contaminant-contaminant increases, inhibiting the deposition behavior of particulate pollutants. In addition, hydrocyclone desorbs contaminants deposited on the separation media and the average contaminant residual rate decreases from 3.3 to 0.2 wt%. We propose an industrial application for treating and reusing MTO wastewater (200 m3/h) using the SRMS technology based on the experimental results. The costs of the wastewater treatment process are as low as 0.25 CNY/m3, and the wastewater reuse rate is over 97% without chemical consumption. This work can provide an environmentally friendly and economically sustainable approach to the source management of MTO wastewater.

Trends in prevalence rates of blindness among patients with diabetic retinopathy in high-income countries from 1990 to 2019: A joinpoint regression analysis.

AIMS: Diabetic retinopathy (DR) is the leading cause of blindness in patients with diabetes mellitus (DM). We investigated its trends in high-income countries to gain insights into preventing DR-related blindness in diabetes-epidemic areas. METHODS: For joinpoint regression analysis, we extracted data from the Global Burden of Disease 2019 study and analysed the prevalence trends of DR-related blindness according to DM type, patients' sex and age, region, and nation. RESULTS: Overall, the age-standardised prevalence rate (ASPR) of DR-related blindness has decreased. The prevalence rates of blindness decreased more sharply for Type 1 DM than for Type 2 DM. The ASPR was higher and the decreasing trend was less pronounced in women than in men. Southern Latin America had the highest ASPR, whereas Australasia had the lowest ASPR. Singapore experienced the greatest decline, whereas unfavourable trends were observed in the USA. CONCLUSIONS: Despite decrease in the overall ASPR of DR-related blindness during the study period, large improvement opportunities were identified. As DM prevalence increases and the population ages rapidly in high-income countries, novel effective screening, treatment, and prevention strategies are urgently needed to improve the visual outcomes of individuals with DM or at risk of DM.

TFormer: A throughout fusion transformer for multi-modal skin lesion diagnosis.

Multi-modal skin lesion diagnosis (MSLD) has achieved remarkable success by modern computer-aided diagnosis (CAD) technology based on deep convolutions. However, the information aggregation across modalities in MSLD remains challenging due to severity unaligned spatial resolution (e.g., dermoscopic image and clinical image) and heterogeneous data (e.g., dermoscopic image and patients' meta-data). Limited by the intrinsic local attention, most recent MSLD pipelines using pure convolutions struggle to capture representative features in shallow layers, thus the fusion across different modalities is usually done at the end of the pipelines, even at the last layer, leading to an insufficient information aggregation. To tackle the issue, we introduce a pure transformer-based method, which we refer to as "Throughout Fusion Transformer (TFormer)", for sufficient information integration in MSLD. Different from the existing approaches with convolutions, the proposed network leverages transformer as feature extraction backbone, bringing more representative shallow features. We then carefully design a stack of dual-branch hierarchical multi-modal transformer (HMT) blocks to fuse information across different image modalities in a stage-by-stage way. With the aggregated information of image modalities, a multi-modal transformer post-fusion (MTP) block is designed to integrate features across image and non-image data. Such a strategy that information of the image modalities is firstly fused then the heterogeneous ones enables us to better divide and conquer the two major challenges while ensuring inter-modality dynamics are effectively modeled. Experiments conducted on the public Derm7pt dataset validate the superiority of the proposed method. Our TFormer achieves an average accuracy of 77.99% and diagnostic accuracy of 80.03% , which outperforms other state-of-the-art methods. Ablation experiments also suggest the effectiveness of our designs. The codes can be publicly available from https://github.com/zylbuaa/TFormer.git.

Mechanical Properties and Microstructure of Hot-Pressed Silica Matrix Composites.

Silica is one of the most widely used ceramics due to its excellent chemical stability and dielectric property. However, its destructive brittle nature inhabits it from wider application as a functional ceramic. An improvement in toughness is a challenging topic for silica ceramic, as well as other ceramics. In the paper, silica ceramic with different types of boron nitride powders and alumina platelets was fabricated by hot-pressing. Introduction of the additives had great influence on the composites' mechanical properties and microstructure. The silica matrix composite containing micro-sized boron nitride powders possessed the best mechanical properties, including the bending strength (134.5 MPa) and the fracture toughness (1.85 Mpa·m1/2). Meanwhile, the introduction of alumina platelets combined with boron nitride nanosheets achieved an effective enhancement of fracture toughness while maintaining the bending strength. Compared with the monolithic silica, the composite with simultaneous addition of alumina platelets and boron nitride nanosheets had a fracture toughness of 2.23 Mpa·m1/2, increased by approximately 27% (1.75 Mpa·m1/2). The crack deflection and platelet pullout were contributing to enhancement of the fracture toughness. The improved mechanical properties, combined with the intrinsic excellent dielectric and chemical properties, make the silica matrix composites promising wave transparent and thermal protection materials.

Influence of Additives on Microstructure and Mechanical Properties of Alumina Ceramics.

Alumina is one of the most commonly used and researched structural ceramic because of its excellent properties. However, its intrinsic brittleness is the fatal drawback, which hinders it from wider applications. How to improve its fracture toughness as well as the bending strength is always challenging for material researchers. In this paper, alumina matrix composites were fabricated by hot-pressing, in which some additives, including zirconia, alumina platelets, and MXene, were incorporated. The influence of the introduced additives on their microstructure and mechanical properties was investigated. Compare with the monolithic alumina, both bending strength and fracture toughness of all samples were improved greatly. Incorporation of zirconia was beneficial to the mechanical properties due to the phase-transformation strengthening and toughening mechanism. While alumina platelets resulted in high fracture toughness because of the self-toughening of elongated grains. The synergistic effect of alumina platelets and MXene enormously improved the fracture toughness from 2.9 ± 0.3 MPa·m1/2 for monolithic alumina to 7.5 ± 0.4 MPa·m1/2 for the composite, which was increased by 159%. This work will provide useful references for the fabrication of high-strength and high-toughness alumina ceramics by introducing additives properly.

Cooperative physical separation of oil and suspended solids from methanol-to-olefin wastewater: A pilot study.

Methanol-to-olefin (MTO) is an important non-petroleum chemical process for the preparation of light olefins. However, the MTO process consumes copious amounts of water and produces large amounts of untreated effluent. Therefore, the realization of efficient wastewater treatment and recycling is key to the green low-carbon development of MTO. Here, a cooperative process combining swirl regenerating micro-channel separation (SRMS) and combined fibrous coalescence (CFC) technologies was proposed to separate high contents of oil and suspended matter in MTO wastewater. Using a pilot device with a treatment capacity of 1 m3/h, the average oil content in MTO wastewater decreased from 750 mg/L to <30 mg/L, while the average content of suspended matter decreased from 108 mg/L to <15 mg/L. Compared with a commercial MTO wastewater treatment process (olefin production capacity of 0.6 million tons per annum), the proposed method could reduce wastewater discharges and costs by 57% and US$ 0.23 million per annum respectively. Equipment costs and operational energy consumption were also reduced by 30% and >95% respectively. The combined process may provide the basis for the green and sustainable treatment of MTO wastewater and its recycling.

Production of Four 15N-Labelled Cobalamins via Biosynthesis Using Propionibacterium freudenreichii.

Cobalamins (vitamin B12) are required by humans for their essential roles as enzyme cofactors in diverse metabolic processes. The four most common cobalamin vitamers are hydroxocobalamin (OHCbl), adenosylcobalamin (AdoCbl), methylcobalamin (MeCbl), and cyanocobalamin (CNCbl). Humans are not able to synthesise cobalamins de novo and thus must acquire them from external sources. Therefore, a reliable and robust analytical method to determine the cobalamins in dietary sources is highly required. For such a purpose, stable isotope dilution assays (SIDAs) with LC-MS/MS are most suited due to their superior sensitivity, specificity, and ability to compensate for matrix effects and analyte loss during sample work-up. However, a critical bottleneck for developing a SIDA method for cobalamins is the availability of stable isotope-labelled internal standards. In the present study, we harnessed the potential of Propionibacterium (P.) freudenreichii for the biosynthesis of 15N-labelled cobalamins. First, we developed a chemically defined medium (CDM) containing ammonium sulphate as a single nitrogen source except three essential vitamins that supported long-term stable growth of P. freudenreichii throughout continuous transfers. The CDM was further optimised for cobalamin production under different incubation schemes. With the optimised CDM and incubation scheme, fully 15N-labelled cobalamins were obtained in P. freudenreichii with a final yield of 312 ± 29 µg/L and 635 ± 102 µg/L, respectively, for [15N]-OHCbl and [15N]-AdoCbl. Additionally, an optimised incubation process under anaerobic conditions was successfully employed to produce specifically labelled [15N, 14N2]-cobalamins, with a yield of 96 ± 18 µg/L and 990 ± 210 µg/L, respectively, for [15N, 14N2]-OHCbl and [15N, 14N2]-AdoCbl. The labelled substances were isolated and purified by solid phase extraction and semi-preparative HPLC. Chemical modifications were carried out to produce [15N]-CNCbl and [15N]-MeCbl. Eventually, 15N-labelled compounds were obtained for the four cobalamin vitamers in high chromatographic and isotopic purity with desired 15N-enrichment and labelling patterns, which are perfectly suited for future use in SIDAs or other applications that require isotopologues.

Development of Stable Isotope Dilution Assays for the Analysis of Natural Forms of Vitamin B12 in Meat.

The first multiple stable isotope dilution assay method was developed for the simultaneous determination of four cobalamins, namely, hydroxocobalamin (OHCbl), adenosylcobalamin (AdoCbl), methylcobalamin (MeCbl), and cyanocobalamin (CNCbl), in their native forms. The sample preparation was optimized with enzyme treatment and immunoaffinity purification. The analysis was performed by LC-MS/MS using respective 15N-labeled cobalamins as internal standards. Method validation resulted in limits of detection ranging from 0.19 to 0.58 ng/g and limits of quantification ranging from 0.68 to 1.73 ng/g. Recoveries at three levels were between 82 and 121%. Intra-day and inter-day precisions were below 6% and 11% RSD, respectively. The analysis of a reference material resulted in a variance of <1% from the certified value. The newly developed method demonstrated excellent sensitivity, recovery, accuracy, and reproducibility and was further applied to quantitate the four cobalamins in various meats.

Simultaneously achieving high-effective oil-water separation and filter media regeneration by facile and highly hydrophobic sand coating.

Efficient oil-water separation, including of emulsified oil separation, is one of the problems restricting the green development of the petrochemical industry. Herein, highly hydrophobic sand was fabricated in one-step, followed by an investigation of adsorption capacity for various oils of hexane, petroleum ether, diesel, tetrachloroethylene and tetrachloromethane. The modified sand (MS) filter bed was subsequently set up to investigate the oil separation efficiency for oil-water mixtures, emulsions and actual petroleum refinery wastewater, respectively. Moreover, the capture process of the oil droplet by the MS was observed by a high-speed camera system, and the oil removal mechanism was explored. The removal feasibility of the oil adhered to the MS in a hydrocyclone was also investigated. The oil could be quickly adsorbed by the MS, and the adsorption capacity was positively correlated with oil density. A high flux of 14,436 L·m-2·h-1 and a considerable separation efficiency of 99% were obtained when the MS was applied for oil-water mixture separation. Additionally, the highest separation efficiency of various emulsions was up to 99.3%. Regrading actual petroleum refinery wastewater, the oil removal efficiency of the MS reached 90% rather than 57.8% of raw sand. The oil droplets in the wastewater were efficiently separated by the MS based on the mechanism of adsorption and coalescence. Additionally, the oil adhered on the MS could be removed, and the oil concentration decreased from 17.6% to 5.2%, which was ascribed to the MS spinning in a hydrocyclone. A novel oil-water separation method of hydrocyclone-intensified filtration by facile and highly hydrophobic sand coating was proposed, and simultaneously the filter media can be effectively regenerated. It is believed that this work might provide a low cost, recyclable and efficient strategy for oil removal, which shows high promise for industrial oily wastewater treatment.