Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 774
Filtrar
1.
Ultramicroscopy ; 261: 113967, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38615523

RESUMO

Atomic-scale electron microscopy traditionally probes thin specimens, with thickness below 100 nm, and its feasibility for bulk samples has not been documented. In this study, we explore the practicality of scanning transmission electron microscope (STEM) imaging with secondary electrons (SE), using a silicon-wedge specimen having a maximum thickness of 18 µm. We find that the atomic structure is present in the entire thickness range of the SE images although the background intensity increases moderately with thickness. The consistent intensity of secondary electron (SE) images at atomic positions and the modest increase in background intensity observed in silicon suggest a limited contribution from SEs generated by backscattered electrons, a conclusion supported by our multislice calculations. We conclude that achieving atomic resolution in SE imaging for bulk specimens is indeed attainable using aberration-corrected STEM and an aberration-corrected scanning electron microscope (SEM) may have the capacity for atomic-level resolution, holding great promise for future strides in materials research.

2.
Ann Anat ; : 152267, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38649115

RESUMO

BACKGROUND: Reasonable postoperative humeroradial and humeroulnar joint spaces maybe an important indicator in biomechanical stability of smart internal fixation surgery for coronoid process basal fractures (CPBF). The aim of this study is to compare elbow articular stresses and elbow-forearm stability under smart internal fixations for the CPBF between normal elbow joint spaces and radius-shortening, and to determine the occult factor of radius-ulna load sharing. METHODS: CT images of 70 volunteers with intact elbow joints were retrospectively collected for accurate three-dimensional reconstruction to measure the longitudinal and transverse joint spaces. Two groups of ten finite element (FE) models were established prospectively between normal joint space and radius-shortening with 2.0mm, including intact elbow joint and forearm, elbow-forearm with CPBF trauma, anterior or posterior double screws-cancellous bone fixation, mini-plate-cancellous bone fixation. Three sets of physiological loads (compression, valgus, varus) were used for FE intelligent calculation, FE model verification, and biomechanical and motion analysis. RESULTS: The stress distribution between coronoid process and radial head, compression displacements and valgus angles of elbow-forearm in the three smart fixation models of the normal joint spaces were close to those of corresponding intact elbow model, but were significantly different from those of preoperative CPBF models and fixed radius-shortening models. The maximum stresses of three smart fixation instrument models of normal joint spaces were significantly smaller than those of the corresponding fixed radius-shortening models. CONCLUSIONS: On the basis of the existing trauma of the elbow-forearm system in clinical practice, which is a dominant factor affecting radius-ulna load sharing, the elbow joint longitudinal space has been found to be the occult factor affecting radius-ulna load sharing. The stability and load sharing of radius and ulna after three kinds of smart fixations of the CPBF is not only related to the anatomical and biomechanical stability principles of smart internal fixations, but also closely related to postoperative elbow joint longitudinal space.

3.
Front Med (Lausanne) ; 11: 1353502, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38590312

RESUMO

Background: Compare the anesthesia effects of combined intravenous and inhalation anesthesia (CIVIA) and total intravenous anesthesia (TIVA) in laparoscopic surgery. Furthermore, our objective is to examine the elements that contribute to the delay in postoperative recovery of neurocognitive function and anticipate the manifestation of delayed recovery by analyzing serum cytokines. Methods: The CIVIA group and the TIVA group both consisted of 130 patients who were scheduled to have elective major abdominal surgery through laparoscopy. The criteria taken into account by the observational and record-keeping study were the patients' ages, sexes, body masses, heights, and the presence or absence of any preexisting problems. Both groups also had their anesthetic depth, duration, and per-unit-of-time muscle relaxant and analgesic dosages recorded. Finally, the length of each patient's stay in the hospital as well as their overall length of stay were tracked. By using the Mini-Mental State Examination (MMSE) to measure cognitive function, we assessed the mental states of the subjects. Additionally, we wanted to identify any biomarkers that could be linked to postoperative cognitive decline or delays in neurocognitive recovery. Results: A total of 51 participants from the CIVIA group and 53 participants from the TIVA group satisfactorily completed the necessary neuropsychological exam for identifying delayed neurocognitive recovery at the study's completion. In the initial data of the two groups, no significant discrepancies were found (p > 0.05). The CIVIA group exhibited noteworthy reductions in the quantity of administered analgesics and muscle relaxants per unit of time in comparison to the TIVA group (p < 0.05). In addition to this, the duration from the sevoflurane tank being closed to the extubation period demonstrated a significant reduction in the CIVIA group compared to the TIVA group (p < 0.05). Moreover, no statistically notable distinction was observed in terms of postoperative hospitalization duration and overall hospitalization duration among both groups (p > 0.05). According to the study, both the CIVIA group and the TIVA group had a total of 7 (13.72%) and 17 (32.07%) individuals, respectively, who met the criteria for neurocognitive delayed recovery (Odds Ratio: 0.336; 95% CI: 0.134-0.864; p = 0.026). According to the research findings, it is indicated that there is a possibility for an increased presence of IL-6 in the bloodstream within 60 min following the incision made on the skin. This occurrence subsequently leads to the prolonged restoration of neurocognitive capabilities. Conclusion: The CIVIA technique outperforms the TIVA method in terms of overall assessment in the setting of laparoscopic surgery. It's also important to remember that an increased blood IL-6 level during laparoscopy may operate as a separate risk factor for a delay in the restoration of neurocognitive function.

4.
Toxicol Res (Camb) ; 13(2): tfae037, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38500513

RESUMO

Background: Epidemiological studies demonstrate that particulate matter 2.5 (PM2.5) exposure closely related to chronic respiratory diseases. Cellular senescence plays an important role in many diseases. However, it is not fully clear whether PM2.5 exposure could induce cellular senescence in the human lung. In this study, we generated a three-dimensional (3D) spheroid model using isolated primary human lung fibroblasts (HLFs) to investigate the effects of PM2.5 on cellular senescence at the 3D level. Methods: 3D spheroids were exposed to 25-100 µg/ml of PM2.5 in order to evaluate the impact on cellular senescence. SA-ß-galactosidase activity, cell proliferation, and the expression of key genes and proteins were detected. Results: Exposure of the HLF spheroids to PM2.5 yielded a more sensitive cytotoxicity than 2D HLF cell culture. Importantly, PM2.5 exposure induced the rapid progression of cellular senescence in 3D HLF spheroids, with a dramatically increased SA-ß-Gal activity. In exploiting the mechanism underlying the effect of PM2.5 on senescence, we found a significant increase of DNA damage, upregulation of p21 protein levels, and suppression of cell proliferation in PM2.5-treated HLF spheroids. Moreover, PM2.5 exposure created a significant inflammatory response, which may be at least partially associated with the activation of TGF-ß1/Smad3 axis and HMGB1 pathway. Conclusions: Our results indicate that PM2.5 could induce DNA damage, inflammation, and cellular senescence in 3D HLF spheroids, which may provide a new evidence for PM2.5 toxicity based on a 3D model which has been shown to be more in vivo-like in their phenotype and physiology than 2D cultures.

5.
Anxiety Stress Coping ; : 1-13, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38506311

RESUMO

BACKGROUND AND OBJECTIVES: The potential detrimental effects of commuting stress have gradually attracted scholars' interest in recent years. Going beyond the perspectives of prior studies (e.g., conservation of resources theory), this study offers a new explanatory framework for the relationship between employees' commuting stress and turnover intention based on the transactional theory of stress. Specifically, this study aims to investigate the mediating effect of hindrance appraisal and the moderating effect of trait mindfulness. DESIGN AND METHOD: To test the hypotheses, we collected two-wave data from 243 employees working in various Chinese firms. Path analysis was used for the analysis. RESULTS: The findings demonstrated that hindrance appraisal mediated the positive relationship between commuting stress and turnover intention. In addition, trait mindfulness buffered the relationship between commuting stress and turnover intention as well as the indirect effect of hindrance appraisal on this relationship. CONCLUSIONS: The findings highlight the stressor appraisal mechanism in the association between commuting stress and turnover intention and identify trait mindfulness as a key coping mechanism for reducing commuting stress.

6.
Environ Res ; 252(Pt 1): 118820, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38555093

RESUMO

As a typical energetic compound widely used in military activities, 2,4,6-trinitrotoluene (TNT) has attracted great attention in recent years due to its heavy pollution and wide distribution in and around the training facilities, firing ranges, and demolition sites. However, the subcellular targets and the underlying toxic mechanism of TNT remain largely unknown. In this study, we explored the toxic effects of TNT biological reduction on the mitochondrial function and homeostasis in Caenorhabditis elegans (C. elegans). With short-term exposure of L4 larvae, 10-1000 ng/mL TNT reduced mitochondrial membrane potential and adenosine triphosphate (ATP) content, which was associated with decreased expression of specific mitochondrial complex involving gas-1 and mev-1 genes. Using fluorescence-labeled transgenic nematodes, we found that fluorescence expression of sod-3 (muls84) and gst-4 (dvls19) was increased, suggesting that TNT disrupted the mitochondrial antioxidant defense system. Furthermore, 10 ng/mL TNT exposure increased the expression of the autophagy-related gene pink-1 and activated mitochondrial unfolded protein response (mt UPR), which was indicated by the increased expression of mitochondrial stress activated transcription factor atfs-1, ubiquitin-like protein ubl-5, and homeobox protein dve-1. Our findings demonstrated that TNT biological reduction caused mitochondrial dysfunction and the development of mt UPR protective stress responses, and provided a basis for determining the potential risks of energetic compounds to living organisms.

7.
Water Res ; 255: 121462, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38493743

RESUMO

Biofouling has been a persistent problem hindering the application of membranes in water treatment, and quorum quenching has been identified as an effective method for mitigating biofouling, but surface accumulation of live bacteria still induces biofilm secretion, which poses a significant challenge for sustained prevention of membrane biofouling. In this study, we utilized quercetin, a typical flavonoid with the dual functions of quorum quenching and bacterial inactivation, to evaluate its role in preventing biofilm proliferation and against biofouling. Quercetin exhibited excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and the decreased bioactivity was positively correlated with the quercetin concentration, with inhibition rates of 53.1 % and 57.4 %, respectively, at the experimental concentrations. The RT-qPCR results demonstrated that quercetin inhibited AI-2 of E. coli and AGR of S. aureus mediated quorum sensing system, and reduced the expression of genes such as adhesion, virulence, biofilm secretion, and key regulatory proteases. As a result, the bacterial growth cycle was retarded and the biomass and biofilm maturation cycles were alleviated with the synergistic effect of quorum quenching and antibacterial activity. In addition, membrane biofouling was significantly declined in the dynamic operation experiments, dead cells in the biofilm overwhelmingly dominated, and the final normalized water fluxes were increased by more than 49.9 % and 34.5 % for E. coli and S. aureus, respectively. This work demonstrates the potential for mitigating biofouling using protocols that quorum quenching and inactivate bacteria, also provides a unique and long-lasting strategy to alleviate membrane fouling.

8.
J Hazard Mater ; 469: 133942, 2024 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-38452675

RESUMO

The spread of bacteriophage-borne antibiotic resistance genes (ARGs) poses a realistic threat to human health. Nanomaterials, as important emerging pollutants, have potential impacts on ARGs dissemination in aquatic environments. However, little is known about its role in transductive transfer of ARGs mediated by bacteriophage in the presence of microplastics. Therefore, this study comprehensively investigated the influence of silver nanoparticles (AgNPs) on the transfer of bacteriophage-encoded ARGs in planktonic Escherichia coli and microplastic-attached biofilm. AgNPs exposure facilitated the phage transduction in planktonic and microplastic-attached bacteria at ambient concentration of 0.1 mg/L. Biological binding mediated by phage-specific recognition, rather than physical aggregation conducted by hydrophilicity and ζ-potential, dominated the bacterial adhesion of AgNPs. The aggregated AgNPs in turn resulted in elevated oxidative stress and membrane destabilization, which promoted the bacteriophage infection to planktonic bacteria. AgNPs exposure could disrupt colanic acid biosynthesis and then reduce the thickness of biofilm on microplastics, contributing to the transfer of phage-encoded ARGs. Moreover, the roughness of microplastics also affected the performance of AgNPs on the transductive transfer of ARGs in biofilms. This study reveals the compound risks of nanomaterials and microplastics in phage-borne ARGs dissemination and highlights the complexity in various environmental scenarios.


Assuntos
Bacteriófagos , Nanopartículas Metálicas , Humanos , Microplásticos , Plásticos , Prata/toxicidade , Bacteriófagos/genética , Plâncton/genética , Bactérias/genética , Antibacterianos/farmacologia , Genes Bacterianos , Escherichia coli/genética
10.
Opt Express ; 32(5): 7318-7331, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38439415

RESUMO

Highly tunable electromagnetically induced transparency (EIT) with high-quality-factor (Q-factor) excited by combining with the quasi-bound states in the continuum (quasi-BIC) resonances is crucial for many applications. This paper describes all-dielectric metasurface composed of silicon cuboid etched with two rectangular holes into a unit cell and periodically arranged on a SiO2 substrate. By breaking the C2 rotational symmetry of the unit cell, a high-Q factor EIT and double quasi-BIC resonant modes are excited at 1224.3, 1251.9 and 1299.6 nm with quality factors of 7604, 10064 and 15503, respectively. We show that the EIT resonance is caused by destructive interference between magnetic dipole resonances and quasi-BIC dominated by electric quadrupole. Toroidal dipole (TD) and electric quadrupole (EQ) dominate the other two quasi-BICs. The EIT window can be successfully modulated with transmission intensity from 90% to 5% and modulation depths ranging from -17 to 24 dB at 1200-1250 nm by integrating the metasurface with an epsilon-near-zero (ENZ) material indium tin oxide (ITO) film. Our findings pave the way for the development of applications such as optical switches and modulators with many potential applications in nonlinear optics, filters, and multichannel biosensors.

11.
Arthritis Res Ther ; 26(1): 67, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38475924

RESUMO

BACKGROUND: To investigate the role of antiphospholipid antibodies (aPLs) in the disease severity and prognosis of SLE-related thrombocytopenia (SLE-TP). METHODS: This multicenter prospective study was conducted based on data from the CSTAR registry. TP was defined as a platelet count<100 × 109/L. Demographic characteristics, platelet count, clinical manifestations, disease activity, and autoantibody profiles were collected at baseline. Relapse was defined as the loss of remission. Bone marrow aspirate reports were also collected. RESULTS: A total of 350 SLE-TP patients with complete follow-up data, 194 (55.4%) were aPLs positive. At baseline, SLE-TP patients with aPLs had lower baseline platelet counts (61.0 × 109/L vs. 76.5 × 109/L, P<0.001), and a higher proportion of moderate to severe cases (24.2% vs. 14.1% ; 18.0% vs. 8.3%, P<0.001). SLE-TP patients with aPLs also had lower platelet counts at their lowest point (37.0 × 109/L vs. 51.0 × 109/L, P = 0.002). In addition, thean increasing number of aPLs types was associated with a decrease in the baseline and minimum values of platelets ( P<0.001, P = 0.001). During follow-up, SLE-TP carrying aPLs had a higher relapse rate (58.2% vs. 44.2%, P = 0.009) and a lower complete response (CR) rate. As the types of aPLs increased, the relapse rate increased, and the CR rate decreased. Furthermore, there was no significant difference in the ratio of granulocytes to red blood cells (G/E), the total number of megakaryocyte and categories. CONCLUSION: SLE-TP patients with positive aPLs had more severe disease a lower remission rate but a higher relapse rate.


Assuntos
Síndrome Antifosfolipídica , Lúpus Eritematoso Sistêmico , Trombocitopenia , Humanos , Anticorpos Antifosfolipídeos , Estudos de Coortes , Estudos Prospectivos , Prognóstico , Gravidade do Paciente , Recidiva
12.
Rheumatol Ther ; 11(2): 397-409, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38349593

RESUMO

INTRODUCTION: Anemia and malnutrition are recognized indicators of suboptimal physical condition in chronic inflammatory diseases. This study aimed to examine the association between anemia, low body mass index (BMI), and clinical outcomes in axial spondyloarthritis (axSpA). METHOD: This cross-sectional analysis utilized data from the multicenter ChinaSpA cohort. A total of 4146 participants with axSpA were categorized into four groups based on BMI and hemoglobin levels: those with both anemia and low BMI, those with anemia only, those with low BMI only, and those with neither condition. Logistic regression analyses were performed to analyze the association between anemia, low BMI, inflammation status, functional impairment, and disease activity. RESULTS: Anemia was present in 13.94%, low BMI in 11.99%, and both conditions in 2.15% of axSpA participants. Those with both anemia and low BMI showed significantly higher levels of inflammation (hypersensitive C-reactive protein [hsCRP] 30.60 mg/L vs. 8.44 mg/L), functional impairment (Bath Ankylosing Spondylitis Functional Index [BASFI] 3.80 vs. 2.10), and disease activity (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] 4.52 ± 2.04 vs. 3.67 ± 2.21; Ankylosing Spondylitis Disease Activity Score calculated with C-reactive protein [ASDAS_CRP] 3.51 ± 1.10 vs. 2.62 ± 1.21) compared to those without these conditions. After adjusting for sex and age, significant associations were observed between elevated hsCRP levels and the presence of low BMI (odds ratio [OR] 1.44, 95% CI 1.17-1.78), anemia (OR 1.91, 95% CI 1.56-2.32), and their concurrent presence (OR 3.59, 95% CI 2.22-5.80). Similarly, increased BASFI was significantly associated with low BMI (OR 1.57, 95% CI 1.25-1.97), anemia (OR 1.47, 95% CI 1.19-1.80), and their combination (OR 3.11, 95% CI 2.02-4.78). CONCLUSION: All-cause anemia and low BMI are prevalent complications in patients with axSpA, exhibiting a significant correlation with elevated inflammation status and functional impairment. The simultaneous occurrence of anemia and low BMI particularly exacerbates clinical outcomes, emphasizing the critical role of comprehensive nutritional assessment and management in the therapeutic strategy for axSpA.

13.
NAR Cancer ; 6(1): zcae008, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38406264

RESUMO

Radiation therapy (RT) is one of the primary treatment modalities of cancer, with 40-60% of cancer patients benefiting from RT during their treatment course. The intrinsic radiosensitivity or acquired radioresistance of tumor cells would affect the response to RT and clinical outcomes in patients. Thus, mining the regulatory mechanisms in tumor radiosensitivity or radioresistance that have been verified by biological experiments and computational analysis methods will enhance the overall understanding of RT. Here, we describe a comprehensive database dbCRAF (http://dbCRAF.xialab.info/) to document and annotate the factors (1,677 genes, 49 proteins and 612 radiosensitizers) linked with radiation response, including radiosensitivity, radioresistance in cancer cells and prognosis in cancer patients receiving RT. On the one hand, dbCRAF enables researchers to directly access knowledge for regulation of radiation response in human cancer buried in the vast literature. On the other hand, dbCRAF provides four flexible modules to analyze and visualize the functional relationship between these factors and clinical outcome, KEGG pathway and target genes. In conclusion, dbCRAF serves as a valuable resource for elucidating the regulatory mechanisms of radiation response in human cancers as well as for the improvement of RT options.

14.
Artigo em Inglês | MEDLINE | ID: mdl-38421846

RESUMO

Randomness is widely introduced in neural network training to simplify model optimization or avoid the over-fitting problem. Among them, dropout and its variations in different aspects (e.g., data, model structure) are prevalent in regularizing the training of deep neural networks. Though effective and performing well, the randomness introduced by these dropout-based methods causes nonnegligible inconsistency between training and inference. In this paper, we introduce a simple consistency training strategy to regularize such randomness, namely R-Drop, which forces two output distributions sampled by each type of randomness to be consistent. Specifically, R-Drop minimizes the bidirectional KL-divergence between two output distributions produced by dropout-based randomness for each training sample. Theoretical analysis reveals that R-Drop can reduce the above inconsistency by reducing the inconsistency among the sampled sub structures and bridging the gap between the loss calculated by the full model and sub structures. Experiments on 7 widely-used deep learning tasks ( 23 datasets in total) demonstrate that R-Drop is universally effective for different types of neural networks (i.e., feed-forward, recurrent, and graph neural networks) and different learning paradigms (supervised, parameter-efficient, and semi-supervised). In particular, it achieves state-of-the-art performances with the vanilla Transformer model on WMT14 English → German translation ( 30.91 BLEU) and WMT14 English → French translation ( 43.95 BLEU), even surpassing models trained with extra large-scale data and expert-designed advanced variants of Transformer models. Our code is available at GitHub https://github.com/dropreg/R-Drop.

15.
FASEB J ; 38(4): e23475, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38334450

RESUMO

Ankyrin-repeat proteins with a suppressor of cytokine signaling box (ASB) proteins belong to the E3 ubiquitin ligase family. 18 ASB members have been identified whose biological functions are mostly unexplored. Here, we discovered that ASB3 was essential for hepatocellular carcinoma (HCC) development and high ASB3 expression predicted poor clinical outcomes. ASB3 silencing induced HCC cell growth arrest and apoptosis in vitro and in vivo. Liver-specific deletion of Asb3 gene suppressed diethylnitrosamine (DEN)-induced liver cancer development. Mechanistically, ASB3 interacted with death receptor 5 (DR5), which promoted ubiquitination and degradation of DR5. We further showed that ASB3 knockdown stabilized DR5 and increased the sensitivity of liver cancer cells to the treatment of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a DR5-dependent manner in cellular and in animal models. In summary, we demonstrated that ASB3 promoted ubiquitination and degradation of DR5 in HCC, suggesting the potential of targeting ASB3 to HCC treatment and overcome TRAIL resistance.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Apoptose , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Ligantes , Neoplasias Hepáticas/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/genética , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Ubiquitinação , Humanos
16.
Water Res ; 253: 121295, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38354663

RESUMO

Biodegradable plastics have been massively produced and used as potential substitutes for conventional plastics, resulting in their inevitable entry into the environment and generation of biodegradable microplastics (MPs). The sulfidation transformation of MPs is an important process for their transformation in anoxic environments (e.g., sediments, anaerobic activated sludges) that can alter their environmental effects and risks. However, how sulfides induce the transformation of biodegradable MPs and whether they are similar to conventional MPs remains unknown. In the present study, we compared the transformation and mechanism of conventional polyethylene (PE) MPs and biodegradable poly(butylene adipate-co-terephthalate) (PBAT) MPs during sulfidation. The results demonstrated that sulfidation resulted in oxidation of PE MPs, whereas PBAT MPs underwent reduction and had higher physical damage, as evidenced by fragmentation, chain scission and organic compound release. Besides, reactive oxygen species and sulfide species played important roles in the sulfidation of PE and PBAT MPs, respectively. The presence of ester groups in PBAT MPs led to their hydrolysis, causing chain scission and further reduction. Furthermore, sulfidation caused a higher degree of adsorption and toxicity alterations in PBAT MPs than in PE MPs. This work uncovers critical abiotic transformation behaviors of biodegradable microplastics and highlights the necessity of considering microplastic structural features to accurately predict microplastic occurrence.


Assuntos
Microplásticos , Plásticos , Polietileno , Adsorção , Clima , Solo
17.
ACS Sens ; 9(2): 654-661, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38329934

RESUMO

A whole-cell biosensor (WCB) is a convenient and cost-effective method for detecting contaminants. However, the practical application of the cadmium WCBs has been hampered by performance deficiencies, such as low sensitivity, specificity, and responsive strength. In this study, to improve the performance of cadmium WCBs, the cadmium transcription factor (CadC) and its DNA binding site (CadO), the key sensing module of the biosensor, were successively and separately subjected to a two-step directed evolution: 6-round random mutagenesis for CadC and 2-round saturation mutagenesis for CadO. For practical application, the GFP reporter gene was replaced with the lacZ gene and a facile and rapid smartphone detection platform for actual water samples was established by optimizing the reaction systems with detergents. The results showed that the evolved cadmium fluorescent biosensor CadO66 exhibited a higher specificity and a detection limit of 0.034 µg/L, representing a 19-fold reduction compared to the wild-type cadmium biosensor. The detergent sodium dodecylbenzenesulfonate effectively enhanced the visualization of WCB B0033-lacZ. Using the fluorescent WCB CadO66 and the visual WCB B0033-lacZ to analyze the cadmium contents of the actual water samples, the results were also consistent with a graphite furnace atomic absorption spectrometer. Taken together, this study indicates that the two-step directed evolution of CadC and CadO can efficiently improve the performance of cadmium WCBs, further promoting the utilization of WCB in actual sample detection and presenting a promising and feasible method for rapid sample detection.


Assuntos
Técnicas Biossensoriais , Cádmio , Cádmio/análise , Cádmio/metabolismo , Águas Residuárias , Genes Reporter , Água , Técnicas Biossensoriais/métodos
18.
Neural Netw ; 172: 106101, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38232426

RESUMO

The Centralized Training and Decentralized Execution (CTDE) paradigm, where a centralized critic is allowed to access global information during the training phase while maintaining the learned policies executed with only local information in a decentralized way, has achieved great progress in recent years. Despite the progress, CTDE may suffer from the issue of Centralized-Decentralized Mismatch (CDM): the suboptimality of one agent's policy can exacerbate policy learning of other agents through the centralized joint critic. In contrast to centralized learning, the cooperative model that most closely resembles the way humans cooperate in nature is fully decentralized, i.e. Independent Learning (IL). However, there are still two issues that need to be addressed before agents coordinate through IL: (1) how agents are aware of the presence of other agents, and (2) how to coordinate with other agents to improve joint policy under IL. In this paper, we propose an inference-based coordinated MARL method: Deep Motor System (DMS). DMS first presents the idea of individual intention inference where agents are allowed to disentangle other agents from their environment. Secondly, causal inference was introduced to enhance coordination by reasoning each agent's effect on others' behavior. The proposed model was extensively experimented on a series of Multi-Agent MuJoCo and StarCraftII tasks. Results show that the proposed method outperforms independent learning algorithms and the coordination behavior among agents can be learned even without the CTDE paradigm compared to the state-of-the-art baselines including IPPO and HAPPO.


Assuntos
Algoritmos , Intenção , Humanos , Políticas , Resolução de Problemas , Reforço Psicológico
19.
Ann Anat ; 253: 152210, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38244942

RESUMO

BACKGROUND: Osseous condition of the mandible was regarded as a key factor influencing stability of implants in the early stage. Finite element analysis was used to assess the effect of bone mass density and alveolar bone resorption (double factors) on stress in a four-unit implant restoration of a free-end edentulous posterior mandible. METHODS: A 3D finite element model was constructed for a single-sided free-end edentulous mandible (from mandibular first premolar to mandibular second molar) containing threaded dental implants. Mandible sensitivity modes were constructed with different alveolar bone resorption levels for normal conditions as well as mild, moderate and severe periodontitis, respectively. Based on the mass density of cancellous bone for four types of bones as the sensitivity parameter, two implant design modes were constructed: Model A (four-unit fixed bridge supported by three implants, implant positions were 34, 36 and 37) and model B: 34 × 36, 37 (37: a single implant crown) (34 × 36: three-unit fixed bridge supported by two implants, implant positions were 34 and 36). A total of 32 sensitivity-based finite element models, grouped in two groups, were constructed. Stress distribution and maximum von Mises stress on cortical bone and cancellous bone around the implant, as well as the surface of implant were investigated by using ABAQUS when vertical loading and 45° oblique loading were applied, respectively. RESULTS: When vertical loading was applied on the implant, maximum von Mises stress on the cortical bone around the implant was assessed to be 4.726 MPa - 13.15 MPa and 6.254 MPa - 13.79 MPa for groups A and B, respectively; maximum stress on the cancellous bone around the implant was 2.641 MPa - 3.773 MPa and 2.864 MPa - 4.605 MPa, respectively; maximum stress on the surface of implant was 14.7 MPa - 21.17 MPa and 21.64 MPa - 30.70 MPa, respectively. When 45° oblique loading was applied on the implant restoration, maximum von Mises stress on the cortical bone around the implant was assessed to be 42.08 MPa - 92.71 MPa and 50.84 MPa - 102.5 MPa for groups A and B, respectively; maximum stress on the cancellous bone around the implant was 4.88 MPa - 25.95 MPa and 5.227 MPa - 28.43 MPa, respectively; maximum stress on the surface of implant was 77.91 MPa - 124.8 MPa and 109.2 MPa - 150.7 MPa, respectively. Stress peak on the cortical bone and that on cancellous bone around the implant increased and decreased with the decrease in bone mass density, respectively. Stress peak on alveolar bone increased with alveolar bone resorption when oblique loading was applied. CONCLUSION: 1. Both alveolar bone resorption and bone mass density (double factors) are critical to implant restoration. Bone mass density may exhibit a more pronounced impact than alveolar bone resorption. 2. From the biomechanical perspective, types I and II bones are preferred for implant restoration, while implantation should be considered carefully in the case of type III bones, or those with less bone mass density accompanied by moderate to severe alveolar bone loss. 3. Splinting crowns restoration is biomechanically superior to single crown restoration.


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Humanos , Perda do Osso Alveolar/cirurgia , Análise de Elementos Finitos , Software , Dente Pré-Molar , Mandíbula/cirurgia , Estresse Mecânico , Análise do Estresse Dentário , Prótese Dentária Fixada por Implante
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 310: 123904, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38262298

RESUMO

Multiple organs are affected by the autoimmune inflammatory connective tissue disease known as systemic lupus erythematosus (SLE). If not diagnosed and treated in a timely manner, it can lead to nephritis and damage to the blood system in severe cases, resulting in the patient's death. Therefore, correct and timely diagnosis and treatment are essential for patients. In this study, a framework based on neural network algorithm and Raman spectroscopy technique was established to diagnose SLE patients. Firstly, we pre-processed the obtained Raman data by three methods: baseline correction, smoothing processing and normalization methods, before using it as input for the model, and then ANN, ResNet and SNN classification models were established. The respective classification accuracies for SLE patients were 89.61%, 85.71%, and 95.65% for the three models, with corresponding AUC values of 0.8772, 0.8100, and 0.9555. The results of the experimental indicate that SNN possesses a good classification effect, and the number of model parameters is only 525,826, which is 414,221 less than that of ResNet model. Since the network only uses 0 and 1 to transmit information, and only has basic operations such as summation, compared with the second-generation artificial neural network, which simplifies the product operation of floating point numbers into multiple addition operations, the network has low energy consumption and is suitable for embedding portable Raman spectrometer for clinical diagnosis. This research highlights the significant potential for quick and precise SLE patient discrimination offered by Raman spectroscopy in conjunction with spiking neural networks.


Assuntos
Lúpus Eritematoso Sistêmico , Análise Espectral Raman , Humanos , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Redes Neurais de Computação , Algoritmos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...