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1.
BMC Infect Dis ; 24(1): 595, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38886649

RESUMO

BACKGROUND AND PURPOSE: The persistent progression of pneumonia is a critical determinant of adverse outcomes in patients afflicted with COVID-19. This study aimed to predict personalized COVID-19 pneumonia progression between the duration of two weeks and 1 month after admission by integrating radiological and clinical features. METHODS: A retrospective analysis, approved by the Institutional Review Board, encompassed patients diagnosed with COVID-19 pneumonia between December 2022 and February 2023. The cohort was divided into training and validation groups in a 7:3 ratio. A trained multi-task U-Net network was deployed to segment COVID-19 pneumonia and lung regions in CT images, from which quantitative features were extracted. The eXtreme Gradient Boosting (XGBoost) algorithm was employed to construct a radiological model. A clinical model was constructed by LASSO method and stepwise regression analysis, followed by the subsequent construction of the combined model. Model performance was assessed using ROC and decision curve analysis (DCA), while Shapley's Additive interpretation (SHAP) illustrated the importance of CT features. RESULTS: A total of 214 patients were recruited in our study. Four clinical characteristics and four CT features were identified as pivotal components for constructing the clinical and radiological models. The final four clinical characteristics were incorporated as well as the RS_radiological model to construct the combined prediction model. SHAP analysis revealed that CT score difference exerted the most significant influence on the predictive performance of the radiological model. The training group's radiological, clinical, and combined models exhibited AUC values of 0.89, 0.72, and 0.92, respectively. Correspondingly, in the validation group, these values were observed to be 0.75, 0.72, and 0.81. The DCA curve showed that the combined model exhibited greater clinical utility than the clinical or radiological models. CONCLUSION: Our novel combined model, fusing quantitative CT features with clinical characteristics, demonstrated effective prediction of COVID-19 pneumonia progression from 2 weeks to 1 month after admission. This comprehensive model can potentially serve as a valuable tool for clinicians to develop personalized treatment strategies and improve patient outcomes.


Assuntos
Inteligência Artificial , COVID-19 , Progressão da Doença , SARS-CoV-2 , Tomografia Computadorizada por Raios X , Humanos , COVID-19/diagnóstico por imagem , COVID-19/epidemiologia , Feminino , Masculino , Estudos Retrospectivos , Pessoa de Meia-Idade , Pulmão/diagnóstico por imagem , Pulmão/patologia , Idoso , Adulto
2.
Sci Rep ; 14(1): 10337, 2024 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-38710802

RESUMO

Infectious diseases have long been a shaping force in human history, necessitating a comprehensive understanding of their dynamics. This study introduces a co-evolution model that integrates both epidemiological and evolutionary dynamics. Utilizing a system of differential equations, the model represents the interactions among susceptible, infected, and recovered populations for both ancestral and evolved viral strains. Methodologically rigorous, the model's existence and uniqueness have been verified, and it accommodates both deterministic and stochastic cases. A myriad of graphical techniques have been employed to elucidate the model's dynamics. Beyond its theoretical contributions, this model serves as a critical instrument for public health strategy, particularly predicting future outbreaks in scenarios where viral mutations compromise existing interventions.


Assuntos
Processos Estocásticos , Humanos , Sistema Imunitário/virologia , Evolução Molecular , Vírus/genética , Vírus/imunologia , Evolução Biológica
3.
BMJ Open ; 14(1): e082403, 2024 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-38267249

RESUMO

INTRODUCTION: Upper limb and core strength training is essential for older adults to safely perform daily activities. However, existing exercise programmes mainly focus on lower limb strength and are not designed or delivered to suit people with different functional capacities. This study describes the design of a two-arm cluster randomised controlled trial to examine the effects of a multicomponent physical activity (PA) programme, Mobility-Fit, on mobility and frailty in older adults living in care facilities. METHODS AND ANALYSIS: 160 older adults from 20 care facilities in Hong Kong will be recruited and randomised by care facilities (1:1) to an intervention or a control group. Participants in the intervention group will attend the Mobility-Fit programme, led by facility-based instructors, three times per week, 45 min per session, for 12 weeks, while the control group will participate in a standard care lower limb strengthening programme offered by the care facility. Participants will then be followed up for 9 months. Mobility-Fit comprises agility, postural coordination, balance and strength training, with suitable dosage based on participant's baseline physical and cognitive function. The primary outcomes encompass upper and lower limb strength, trunk stability, reaction time, mobility function and fall efficacy. Secondary outcomes comprise daily PA level and performance, frailty, cognitive function and quality of life. A repeated measures analysis of variance (ANOVA) and generalised estimating equation (GEE) will be used to examine changes in outcomes over time and between groups. Data will be analysed following the intention-to-treat principles. We will also evaluate programme implementation and health economics throughout the follow-up period. ETHICS AND DISSEMINATION: Ethical approval was acquired in November 2022 from the Joint CUHK-NTEC Clinical Research Ethics Committee in Hong Kong (CREC-2022-459). Informed consent will be obtained from participants. The results of the study will be disseminated through peer-reviewed articles, conference presentations and social media. TRIAL REGISTRATION NUMBER: ChiCTR2300072709.


Assuntos
Fragilidade , Humanos , Idoso , Qualidade de Vida , Análise de Variância , Exercício Físico , Extremidade Inferior , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
Biomater Sci ; 12(3): 596-620, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38054499

RESUMO

Antibiotic resistance is a growing problem that requires alternative antibacterial agents. MoS2, a two-dimensional transition metal sulfide, has gained significant attention in recent years due to its exceptional photocatalytic performance, excellent infrared photothermal effect, and impressive antibacterial properties. This review presents a detailed analysis of the antibacterial strategies and mechanism of MoS2, starting with its morphology and synthesis methods and focusing on the different interaction stages between MoS2 and bacteria. The paper summarizes the main antibacterial mechanisms of MoS2, such as photocatalytic antibacterial, enzyme-like catalytic antibacterial, physical antibacterial, and photothermal-assisted antibacterial. It offers a comprehensive discussion focus on recent research studies of photocatalytic antibacterial mechanisms and categorizes them, guiding the application of MoS2 in the antibacterial field. Overall, the review provides an in-depth understanding of the antibacterial mechanisms of MoS2 and presents the challenges and future directions for the improvement of MoS2 in the field of high-efficiency antibacterial materials.


Assuntos
Antibacterianos , Molibdênio , Molibdênio/farmacologia , Antibacterianos/farmacologia , Catálise , Sulfetos
5.
Trends Immunol ; 44(12): 1031-1045, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37932176

RESUMO

Tumor immunotherapy is refashioning traditional treatments in the clinic for certain tumors, especially by relying on the activation of T cells. However, the safety and effectiveness of many antitumor immunotherapeutic agents are suboptimal due to difficulties encountered in assessing T cell responses and adjusting treatment regimens accordingly. Here, we review advances in the clinical visualization of T cell activity in vivo, and focus particularly on molecular imaging probes and biomarkers of T cell activation. Current challenges and prospects are also discussed that aim to achieve a better strategy for real-time monitoring of T cell activity, predicting prognoses and responses to tumor immunotherapy, and assessing disease management.


Assuntos
Antineoplásicos , Neoplasias , Humanos , Linfócitos T , Neoplasias/terapia , Imunoterapia/métodos , Imagem Molecular
6.
Int J Biol Macromol ; 253(Pt 5): 127222, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37797846

RESUMO

The rapid development of modern electrical engineering puts forward urgent demand for high-performance electrical insulating materials. In this study, inspired by the layered structure of natural nacre, we present a novel biomimetic composite insulating film (referred to as M/C film) that is derived from agricultural waste corncobs and industrial waste mica tailings through a sol-gel-film transformation process. The novel insulating film has excellent tensile strength (94 MPa), high dielectric strength (68 kV mm-1), low dielectric loss, good heat resistance (T0 = 235 °C), and excellent UV shielding properties. Meanwhile, the M/C film presents environmental impacts much lower than those petrochemical-based plastic film as it can be 100 % recycled in a closed-loop recycling process and easily biodegraded in the environment (lignocellulose goes back to the carbon cycle and the mica return to the geological cycle). It is a potential alternative for petrochemical plastics and provides a possible way to utilize agricultural waste and mica tailings.


Assuntos
Silicatos de Alumínio , Lignina , Resistência à Tração
7.
Biol Direct ; 18(1): 58, 2023 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-37710294

RESUMO

M7G modification, known as one of the common post-transcriptional modifications of RNA, is present in many different types of RNAs. With the accurate identification of m7G modifications within RNAs, their functional roles in the regulation of gene expression and different physiological functions have been revealed. In addition, there is growing evidence that m7G modifications are crucial in the emergence of cancer. Here, we review the most recent findings regarding the detection techniques, distribution, biological functions and Regulators of m7G. We also summarize the connections between m7G modifications and cancer development, drug resistance, and tumor microenvironment as well as we discuss the research's future directions and trends.


Assuntos
Neoplasias , Humanos , Neoplasias/genética , RNA/genética , Microambiente Tumoral/genética
8.
Infect Drug Resist ; 16: 2727-2735, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37168514

RESUMO

Purpose: This study aimed to investigate the prevalence and genetic characterization of Serratia marcescens isolates from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. Methods: S. marcescens was identified by the polymerase-chain reaction of 16S rRNA gene and sequencing. Antimicrobial susceptibility was tested by the disk diffusion method. Genes of resistance and virulence were determined by the PCR. Results: Overall, S. marcescens were confirmed from 32 of 2897 (1.1%) mastitis milk samples. These isolates showed high resistance to cefazolin (30/32, 93.8%) and chloramphenicol (28/32, 87.5%). A 12.5% (4/32) of the isolates displayed multidrug resistance (MDR). The most prevalent resistant genes found in S. marcescens were TEM (32/32, 100%) and CTX-M (24/32, 75.0%; CTX-M-15, 14/32, 43.8%; CTX-M-14, 8/32, 25.0%; CTX-M-65, 2/32, 6.3%) for extended-spectrum beta-lactamase, cmlA (28/32, 87.5%) and floR (16/32, 50.0%) for chloramphenicol resistance, SIM-1 (2/32, 6.3%) for carbapenemases, and sdeB (28/32, 87.5%), sdeY (26/32, 81.3%), sdeR (26/32, 81.3%) and sdeD (20/32, 62.5%) for efflux pumps. Moreover, all isolates carried virulence genes flhD, entB, and kpn, and most of them contained mrkD (30/32, 93.8%), ycfM (26/32, 81.3%), bsmB (26/32, 81.3%), pigP (26/32, 81.3%), kfu (24/32, 75.0%) and shlB (24/32, 75.0%). Conclusion: To our knowledge, this is the first report of genetic determinants for antimicrobial resistance and virulence in S. marcescens isolated from bovine mastitis cases in China. These findings are useful for developing strategies for prevention and treatment of bovine mastitis caused by S. marcescens in China.

9.
ACS Appl Mater Interfaces ; 15(19): 23371-23379, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37155833

RESUMO

Memristive devices, regardless of their potential applications in memory and computing scenarios, still suffer from large cycle-to-cycle and device-to-device variations due to the stochastic growth of conductive filaments (CFs). In this work, we fabricated a crossbar memristor using the 2D TiSe2 material and then oxidized it into TiO2 in the atmosphere at a moderate temperature. Such a mild oxidation approach fails to evaporate all Se into the air, and after further annealing using thermal or electrical stimulations, the remnant Se atoms gather near the interfaces and grow into nanosized crystals with relatively high conductivity. The resulting peninsula-shaped nanocrystals distort the electric field, forcing CFs to grow on them, which could largely confine the location and length of CFs. As a result, this two-terminal TiSe2/TiO2/TiSe2 device exhibits excellent resistive switching performance with a fairly low threshold voltage (Vset < 0.8 V, Vreset > 0.55 V) and high cycle-to-cycle consistency, enabling resistive switching at narrow operating variations, e.g., 500 ± 48 and 845 ± 39 mV. Our work offers a new approach to minimize the cycle-to-cycle stochasticity of the memristive device, paving the way for its applications in data storage and brain-inspired computing.

10.
Chemistry ; 29(39): e202301157, 2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37156726

RESUMO

In recent years, the strategy of merging visible light photocatalysis and organocatalysis has been utilized and applied in a wide range of reactions. Taking advantage of synergistic visible light photocatalysis with organocatalysis, remarkable progress has recently been achieved in modern chemical synthesis. In these dual catalytic systems, photocatalysts or photosensitizers absorb visible light to induce their photo-excited states which can activate unreactive substrates via electron or energy transfer mechanisms, and organocatalysts are usually employed to control the chemical reactivities of the other substrates. This review mainly focuses on the recent development of cooperative catalysis by the combination of organocatalysis and photocatalysis in recent organic synthesis.

11.
Ann Bot ; 131(5): 867-883, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-36976653

RESUMO

BACKGROUND AND AIMS: Artemisia is a mega-diverse genus consisting of ~400 species. Despite its medicinal importance and ecological significance, a well-resolved phylogeny for global Artemisia, a natural generic delimitation and infrageneric taxonomy remain missing, owing to the obstructions from limited taxon sampling and insufficient information on DNA markers. Its morphological characters, such as capitulum, life form and leaf, show marked variations and are widely used in its infrageneric taxonomy. However, their evolution within Artemisia is poorly understood. Here, we aimed to reconstruct a well-resolved phylogeny for global Artemisia via a phylogenomic approach, to infer the evolutionary patterns of its key morphological characters and to update its circumscription and infrageneric taxonomy. METHODS: We sampled 228 species (258 samples) of Artemisia and its allies from both fresh and herbarium collections, covering all the subgenera and its main geographical areas, and conducted a phylogenomic analysis based on nuclear single nucleotide polymorphisms (SNPs) obtained from genome skimming data. Based on the phylogenetic framework, we inferred the possible evolutionary patterns of six key morphological characters widely used in its previous taxonomy. KEY RESULTS: The genus Kaschgaria was revealed to be nested in Artemisia with strong support. A well-resolved phylogeny of Artemisia consisting of eight highly supported clades was recovered, two of which were identified for the first time. Most of the previously recognized subgenera were not supported as monophyletic. Evolutionary inferences based on the six morphological characters showed that different states of these characters originated independently more than once. CONCLUSIONS: The circumscription of Artemisia is enlarged to include the genus Kaschgaria. The morphological characters traditionally used for the infrageneric taxonomy of Artemisia do not match the new phylogenetic tree. They experienced a more complex evolutionary history than previously thought. We propose a revised infrageneric taxonomy of the newly circumscribed Artemisia, with eight recognized subgenera to accommodate the new results.


Assuntos
Artemisia , Filogenia , Artemisia/genética , Folhas de Planta , Núcleo Celular
12.
Chemosphere ; 324: 138356, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36898437

RESUMO

Decreasing bioaccessible antibiotics, heavy metals, and antibiotic resistance genes (ARGs) in soil by adsorption is an attractive, but unrealized, approach for ARG risk reduction. This approach has the potential to reduce the (co)selection pressure from antibiotics and heavy metals on bacteria and ARG horizontal gene transformation to pathogens. Here, a wet-state silicon-rich biochar/ferrihydrite composite (SiC-Fe(W)) synthesized by loading ferrihydrite onto rice straw-derived biochar was examined for i) adsorption of oxytetracycline and Cu2+ to reduce (co)selection pressure and ii) adsorption of extracellular antibiotic resistance plasmid pBR322 (containing tetA and blaTEM-1) to inhibit ARG transformation. SiC-Fe(W) gained the adsorption priority of biochar (for Cu2+) and wet-state ferrihydrite (for oxytetracycline and pBR322) and showed adsorptive enhancement (for Cu2+ and oxytetracycline) from a more wrinkled and exposed surface from biochar silica-dispersed ferrihydrite and a more negatively charged biochar, and the adsorption capacity for SiC-Fe(W) was 17-135 times that of soil. Correspondingly, 10 g/kg SiC-Fe(W) amendment increased the soil adsorption coefficient Kd by 31%-1417% and reduced the selection pressure from dissolved oxytetracycline, co-selection pressure from dissolved Cu2+, and transformation frequency of pBR322 (assessed with Escherichia coli). The development of Fe-O-Si bonds on silicon-rich biochar in alkaline enhanced ferrihydrite stability and adsorption capacity (for oxytetracycline), presenting a new potential strategy of biochar/ferrihydrite composite synthesis for adsorptive inhibition of ARG proliferation and transformation in ARG pollution control.


Assuntos
Metais Pesados , Oxitetraciclina , Poluentes do Solo , Antibacterianos/farmacologia , Silício/farmacologia , Adsorção , Poluentes do Solo/análise , Metais Pesados/análise , Carvão Vegetal/farmacologia , Carvão Vegetal/química , Solo/química , Resistência Microbiana a Medicamentos/genética , Proliferação de Células
13.
Biomater Sci ; 11(8): 2898-2911, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-36883448

RESUMO

Since nanozymes were proposed, their applications have become more and more extensive. As a research hotspot in recent years, MoS2 also shows many enzyme-like properties. However, as a novel peroxidase, MoS2 has the disadvantage of a low maximum reaction rate. In this study, the MoS2/PDA@Cu nanozyme was synthesized by a wet chemical method. The modification of PDA on the surface of MoS2 achieved the uniform growth of small-sized Cu Nps. The obtained MoS2/PDA@Cu nanozyme displayed excellent peroxidase-like activity and antibacterial properties. The minimum inhibitory concentration (MIC) of the MoS2/PDA@Cu nanozyme against S. aureus reached 25 µg mL-1. Furthermore, it showed a more pronounced inhibitory effect on bacterial growth with the addition of H2O2. The maximum reaction rate (Vmax) of the MoS2/PDA@Cu nanozyme is 29.33 × 10-8 M s-1, which is significantly higher as compared to that of HRP. It also exhibited excellent biocompatibility, hemocompatibility and potential anticancer properties. When the concentration of the nanozyme was 160 µg mL-1, the viabilities of 4T1 cells and Hep G2 cells were 45.07% and 32.35%, respectively. This work indicates that surface regulation and electronic transmission control are good strategies for improving peroxidase-like activity.


Assuntos
Molibdênio , Peroxidase , Molibdênio/química , Staphylococcus aureus , Peróxido de Hidrogênio/farmacologia , Peroxidases/farmacologia , Corantes/farmacologia , Antibacterianos/química
14.
Sci Total Environ ; 875: 162652, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36894094

RESUMO

The char component of biochar can act as an electron shuttle and redox agent to accelerate the transformation of ferrihydrite, but how the silicon component of biochar affects ferrihydrite transformation and pollutant removal remains unclear. In this paper, infrared spectroscopy, electron microscopy, transformation experiments and batch sorption experiments were conducted to examine a 2-line ferrihydrite formed by alkaline precipitation of Fe3+ on a rice straw-derived biochar. Fe-O-Si bonds were developed between the precipitated ferrihydrite particles and biochar silicon component, increasing mesopore volume (for mesopores with diameters of 10-100 nm) and surface area of ferrihydrite as the Fe-O-Si formation probably alleviated the aggregation of ferrihydrite particles. The Fe-O-Si bonding-contributed interactions blocked the transformation to goethite for ferrihydrite precipitated on biochar in a 30-day ageing and a 5-day Fe2+ catalysis ageing. Moreover, there was an increase of oxytetracycline adsorption capacity onto ferrihydrite-loaded biochar, which reached amazingly 3460 mg/g at the maximum, due to the Fe-O-Si bonding-contributed increase of surface area and oxytetracycline coordination sites. Ferrihydrite-loaded biochar as a soil amendment enhanced oxytetracycline adsorption and reduced the bacterial toxicity of dissolved oxytetracycline better than ferrihydrite did. These results provide new perspectives for the role of biochar (especially its silicon component) as an iron-based material carrier and a soil additive in the environmental effects of iron (hydr) oxides in water and soil.


Assuntos
Oxitetraciclina , Silício , Adsorção , Compostos Férricos/química , Ferro/química , Carvão Vegetal/química , Solo
15.
Infect Drug Resist ; 15: 7363-7367, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36540100

RESUMO

This study aimed to investigate the effects of ascorbic acid on antibiotic susceptibility of major bovine mastitis pathogens, including Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus agalactiae, and Escherichia coli. Minimum inhibitory concentrations (MICs) were determined by E-test method. The presence of 10 mM ascorbic acid decreased the MICs of penicillin and ampicillin while increased the MICs of erythromycin, kanamycin, streptomycin, and ciprofloxacin for all tested strains. Besides, ascorbic acid specifically reduced the MICs of tetracycline for gram-positive bacteria and chloramphenicol for gram-negative bacteria. This study highlights that ascorbic acid is a potential modulator of antibiotic activity against the major bovine mastitis pathogens.

16.
Int J Mol Sci ; 23(19)2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36232464

RESUMO

The intestinal barrier is vital for preventing inflammatory bowel disease (IBD). The objectives of this study were to assess whether the Lactobacillus rhamnosus CY12 could alleviate oxidative stress, inflammation, and the disruption of tight junction (TJ) barrier functions induced by lipopolysaccharide (LPS), and therefore to explore the potential underlying molecular mechanisms. Our results showed that LPS-induced Cancer coli-2 (Caco-2) cells significantly increased the levels of reactive oxygen species (ROS), lactate dehydrogenase, inflammatory cytokines interleukin-1ß, interleukin-6, interleukin-8, and tumor necrosis factor-α (IL-1ß, IL-6, IL-8, and TNF-α), and the cell apoptosis rate while decreasing the levels of TJ proteins occludin, zonula occludens-1 (ZO-1), and claudin and antioxidant enzymes, such as catalase, superoxide dismutase, and glutathione peroxidase(CAT, SOD, and GSH-Px) (p < 0.05). However, Lactobacillus rhamnosus CY12 could relieve cytotoxicity, apoptosis, oxidative stress, and pro-inflammatory cytokine expressions, and also inhibit the Toll-like receptor 4/nuclear factor kappa-B(TLR4/NF-κB) signaling pathway. Furthermore, the gene expression of antioxidant enzymes, as well as the mRNA and protein expressions of TJ proteins, was improved. Particularly, the concentration of 108 cfu/mL significantly prevented the inflammatory injury induced by LPS in Caco-2 cells (p < 0.05). These findings support a potential application of Lactobacillus rhamnosus CY12 as a probiotic to prevent LPS-induced intestinal injury and treat intestinal barrier dysfunction.


Assuntos
Lacticaseibacillus rhamnosus , Proteínas de Junções Íntimas , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Células CACO-2 , Catalase/metabolismo , Claudinas/metabolismo , Glutationa Peroxidase/metabolismo , Humanos , Inflamação , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Lactato Desidrogenases/metabolismo , Lacticaseibacillus rhamnosus/metabolismo , Lipopolissacarídeos/farmacologia , NF-kappa B/metabolismo , Ocludina/genética , Ocludina/metabolismo , Estresse Oxidativo , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio , Superóxido Dismutase/metabolismo , Proteínas de Junções Íntimas/metabolismo , Receptor 4 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
17.
Front Chem ; 10: 855352, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35308786

RESUMO

Waterborne polyurethane has been proven to be an ideal additive for the preparation of hydrogels with excellent mechanical properties. This work reports that a satisfactory adhesion of acrylamide hydrogels can be obtained by introducing a large amount of waterborne polyurethane into system. A series of polyurethane hydrogels was prepared by using one-pot method with acrylamide monomer and 2-hydroxymethyl methacrylate end-modified waterborne polyurethane emulsion. The hydrogels exhibit good strength (greater than 30 KPa), wide range of adjustable strain (200%-800%), and excellent compression fatigue resistance. The performance improvement is attributed to the fact that the polyurethane emulsion containing double bonds provides chemical crosslinking and forms polyurethane microregions due to hydrophilic and hydrophobic interactions. The hydrogel shows extensive and repeatable adhesion on diverse substrates. This simple preparation method through polyurethane crosslinked hydrogels is expected to become a low-cost and efficient preparation strategy for hydrogel adhesives.

18.
Huan Jing Ke Xue ; 43(1): 349-362, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989519

RESUMO

In this study, 50 surface water and sediment samples were collected from 25 sampling points in Qingpu District (including Taipu River basin, Jinze Reservoir, and Qingxi country park) in the Yangtze River Delta integration demonstration area, and 22 pharmaceuticals and personal care products (PPCPs) in the samples were analyzed using high-performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS). The distribution characteristics, sources, and influencing factors of targeted PPCPs in the study area were studied in detail. The ecological and health risks of the target PPCPs were evaluated using the quotients method. The results showed that a total of 19 PPCPs were detected in the surface water and sediment samples from 25 sampling points in Qingpu District, with total concentrations ranging from 0.06 to 178.67 ng·L-1 and 0.07 to 37.68 ng·g-1, respectively. The average value of sulfachloropyridazine (SCP) in the surface water was the highest with a concentration of 129.54 ng·L-1, whereas the average value of sulfamethoxazole (SMX) in the sediment was the highest with a concentration of 70.62 ng·g-1. The spatial distribution of the total amount of PPCPs showed a trend of Qingxi country park > Jinze Reservoir > Taipu River basin. Principal component analysis showed that the main sources of pollution were animal antibiotics used in aquaculture and the discharge of domestic sewage. There was a significant correlation between lg Koc and lg Kd (P<0.05), indicating that the organic carbon plays an important role in the distribution of the target PPCPs in water and sediments. The ecological risk assessment results revealed that the fungicides (TCC and TCS) in the surface waters showed a moderate risk to aquatic organisms of different trophic levels. The Qingxi country park and Jinze Reservoir were the regions with the highest ecological risks of PPCPs in surface water and sediment. The health risk entropy (HQ) of people of all age groups exposed through drinking was less than 1; however, with the continuous emission and accumulation of PPCPs, the pollution control of PPCPs in the environment still requires further attention.


Assuntos
Cosméticos , Preparações Farmacêuticas , Poluentes Químicos da Água , Animais , China , Cosméticos/análise , Monitoramento Ambiental , Humanos , Multimídia , Medição de Risco , Rios , Água , Poluentes Químicos da Água/análise
19.
ACS Biomater Sci Eng ; 7(11): 5014-5021, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34597016

RESUMO

Natural materials developed in complex architectures that comprise hard and soft phases often display extraordinary mechanical properties, such as the combination of high strength and toughness. Besides the structural arrangements, residual stress is ubiquitous in those materials. Although evidence shows its significant role in the functionalities and properties of the composites, good or bad, residual stress is not fully understood and utilized. In this study, we show through extensive numerical simulations the role of the prestress in strengthening typical brick-and-mortar biocomposites. We investigate the influence of the prestressing modes, as well as the geometrical and material parameters. The results promise a deep understanding of the relation between the prestress and the material strength and may inspire a new dimension of material design.

20.
Materials (Basel) ; 14(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361428

RESUMO

To ensure safety and prevent failure of engineering equipment throughout its lifespan, the concept of 'Safety Design' is proposed, which covers all the cradle-to-grave phases of engineering equipment, considers at least ten essential factors of failure causes, and conducts root cause analysis at three different scales, in order to proactively control the safety risks before the occurrence of failure rather than passively conduct the remedial measures after failure. Herein, in order to demonstrate how to implement this effective and efficient concept in engineering practice, a case study of failure analysis and prevention is addressed on the extraction column in the production line for methyl methacrylate. Based on the analysis results, the causes were finally determined to be all derived from the stages before operation, including inappropriate design, limited quality inspection of fabrication and installation. Pertinent countermeasures were then proposed from the 'Safety Design' point of view, which would not only solve the failure problem for this sole equipment but also contribute to safety risk control of other engineering equipment before operation.

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