Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 133
Filtrar
1.
Nature ; 617(7962): 738-742, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37100919

RESUMO

Cities are generally warmer than their adjacent rural land, a phenomenon known as the urban heat island (UHI). Often accompanying the UHI effect is another phenomenon called the urban dry island (UDI), whereby the humidity of urban land is lower than that of the surrounding rural land1-3. The UHI exacerbates heat stress on urban residents4,5, whereas the UDI may instead provide relief because the human body can cope with hot conditions better at lower humidity through perspiration6,7. The relative balance between the UHI and the UDI-as measured by changes in the wet-bulb temperature (Tw)-is a key yet largely unknown determinant of human heat stress in urban climates. Here we show that Tw is reduced in cities in dry and moderately wet climates, where the UDI more than offsets the UHI, but increased in wet climates (summer precipitation of more than 570 millimetres). Our results arise from analysis of urban and rural weather station data across the world and calculations with an urban climate model. In wet climates, the urban daytime Tw is 0.17 ± 0.14 degrees Celsius (mean ± 1 standard deviation) higher than rural Tw in the summer, primarily because of a weaker dynamic mixing in urban air. This Tw increment is small, but because of the high background Tw in wet climates, it is enough to cause two to six extra dangerous heat-stress days per summer for urban residents under current climate conditions. The risk of extreme humid heat is projected to increase in the future, and these urban effects may further amplify the risk.


Assuntos
Cidades , Clima , Transtornos de Estresse por Calor , Temperatura Alta , Umidade , Chuva , Humanos , Cidades/epidemiologia , Temperatura Alta/efeitos adversos , Tempo (Meteorologia) , Umidade/efeitos adversos , Fatores de Risco , Transtornos de Estresse por Calor/epidemiologia , Transtornos de Estresse por Calor/etiologia , Transtornos de Estresse por Calor/prevenção & controle , População Rural , Modelos Climáticos , População Urbana , Estações do Ano
2.
Small ; 20(28): e2311164, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38295083

RESUMO

Smart hydrogels are a promising candidate for the development of next-generation soft materials due to their stimuli-responsiveness, deformability, and biocompatibility. However, it remains challenging to enable hydrogels to actively adapt to various environmental conditions like living organisms. In this work, supramolecular additives are introduced to the hydrogel matrix to confer environmental adaptiveness. Specifically, their microstructures, swelling behaviors, mechanical properties, and transparency can adapt to external environmental conditions. Moreover, the presence of hydrogen bonding provides the hydrogel with applicable rheological properties for 3D extrusion printing, thus allowing for the facile preparation of thickness-dependent camouflage and multistimuli responsive complex. The environmentally adaptive hydrogel developed in this study offers new approaches for manipulating supramolecular interactions and broadens the capability of smart hydrogels in information security and multifunctional integrated actuation.

3.
Opt Lett ; 49(1): 41-44, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38134147

RESUMO

The plasma filament induced by photo-ionization in transparent media (e.g., air) is a competitive terahertz (THz) source, whose mechanism has been widely studied in two separate schemes, i.e., the one- or two-color femtosecond laser filamentation. However, the physical commonality of these two schemes is less explored currently, and a common theory is in urgent need. Here, we proposed the traveling-wave antenna (TWA) model applicable to both single- and dual-color laser fields, which successfully reproduced the reported far-field THz angular distribution/dispersion from different filament lengths with either a constant or a varied plasma density. This work paves the way toward a deeper understanding of the important laser-filament-based THz sources within the same theoretical framework.

4.
BMC Psychiatry ; 24(1): 312, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38658863

RESUMO

BACKGROUND: Cognitive impairment (CoI), chronic kidney disease (CKD), and depression are prevalent among older adults and are interrelated, imposing a significant disease burden. This study evaluates the association of CKD and depression with CoI and explores their potential interactions. METHOD: Data for this study were sourced from the 2011-2014 National Health and Nutritional Examination Survey (NHANES). Multiple binary logistic regression models assessed the relationship between CKD, depression, and CoI while controlling for confounders. The interactions were measured using the relative excess risk of interaction (RERI), the attributable proportion of interaction (AP), and the synergy index (S). RESULTS: A total of 2,666 participants (weighted n = 49,251,515) were included in the study, of which 700 (16.00%) had CoI. After adjusting for confounding factors, the risk of CoI was higher in patients with CKD compared to non-CKD participants (odds ratio [OR] = 1.49, 95% confidence interval [CI]:1.12-1.99). The risk of CoI was significantly increased in patients with depression compared to those without (OR = 2.29, 95% CI: 1.73-3.03). Furthermore, there was a significant additive interaction between CKD and depression in terms of the increased risk of CoI (adjusted RERI = 2.01, [95% CI: 0.31-3.71], adjusted AP = 0.50 [95% CI: 0.25-0.75], adjusted S = 2.97 [95% CI: 1.27-6.92]). CONCLUSION: CKD and depression synergistically affect CoI, particularly when moderate-to-severe depression co-occurs with CKD. Clinicians should be mindful of the combined impact on patients with CoI. Further research is needed to elucidate the underlying mechanisms and assess the effects specific to different CKD stages.


Assuntos
Disfunção Cognitiva , Depressão , Inquéritos Nutricionais , Insuficiência Renal Crônica , Humanos , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/psicologia , Insuficiência Renal Crônica/complicações , Masculino , Feminino , Disfunção Cognitiva/epidemiologia , Pessoa de Meia-Idade , Idoso , Depressão/epidemiologia , Depressão/complicações , Depressão/psicologia , Comorbidade , Estados Unidos/epidemiologia , Adulto , Idoso de 80 Anos ou mais , Estudos Transversais
5.
J Environ Manage ; 358: 120838, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38608576

RESUMO

The soil selenium (Se) content and bioavailability are important for human health. In this regard, knowing the factors driving the concentration of total Se and bioavailable Se in soils is essential to map Se, enhance foodstuffs' Se content, and improve the Se nutritional status of humans. In this study, total Se and Se bioavailability (i.e., phosphate extracted Se) in surface soils (0-20 cm) developed on different strata were analyzed in a Se-enriched region of Southwest China. Furthermore, the interaction between the stratum and soil properties was assessed and how did the stratum effect on the concentration and spatial distribution of Se bioavailability in soils was investigated. Results showed that the median concentration of total Se in soils was 0.308 mg/kg, which is higher than China's soil background. The mean proportion of phosphate extracted Se in total Se was 12.2 %. The values of total Se, phosphate extracted Se, and soil organic matter (SOM) in soils increased with the increasing stratum age. In contrast, the coefficient of weathering and eluviation (BA) values decreased. The analysis of statistics and Geodetector revealed that the SOM, stratum, and BA were the dominant controlling factors for the contents and distributions of soil total Se and phosphate extracted Se. This study provided strong evidence that the soil properties that affected the total Se and Se bioavailability were modulated by the local geological background, and had important practical implications for addressing Se malnutrition and developing the Se-rich resource in the study region and similar geological settings in different parts of the globe.


Assuntos
Selênio , Solo , Selênio/análise , Solo/química , China , Disponibilidade Biológica , Poluentes do Solo/análise
6.
Int Heart J ; 65(2): 237-245, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38556334

RESUMO

Serum chloride level has clinical significance in the prognosis of heart failure. Little is known regarding the association between serum chloride levels and in-hospital mortality in patients with heart failure.This retrospective study used clinical data obtained from the Medical Information Mart for Intensive Care Database. The study cohort comprised patients who were categorized on the basis of their serum chloride levels, and the primary endpoint was in-hospital mortality. To assess the impact of serum chloride levels at the time of intensive care unit admission on in-hospital mortality, we used various statistical approaches, including multivariable logistic regression models, a generalized additive model, and a two-piecewise linear regression model. In addition, subgroup analysis was conducted to examine the robustness of the main findings.This study comprised 15,983 participants. When compared with the reference group (Q5), the groups with the highest (Q7) and lowest (Q1) blood chloride levels exhibited increased in-hospital mortality, with fully adjusted odds ratios (ORs) of 1.36 [95% confidence interval (CI): 1.08-1.71] and 1.25 (95% CI: 1-1.56), respectively. A U-shaped relationship was observed between blood chloride levels and in-hospital mortality, with the lowest risk observed at a threshold of 105.017 mmol/L. The effect sizes and corresponding CIs below and above the threshold were 0.969 (95% CI: 0.957-0.982) and 1.039 (95% CI: 1.002-1.076), respectively. Stratified analyses demonstrated the robustness of this correlation.The relationship between serum chloride levels and in-hospital mortality in patients with heart failure was U-shaped, with an inflection point of 105.017 mmol/L.


Assuntos
Cloretos , Insuficiência Cardíaca , Humanos , Mortalidade Hospitalar , Estudos Retrospectivos , Unidades de Terapia Intensiva
7.
Inflammopharmacology ; 32(1): 229-247, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38012459

RESUMO

Recently, a global outbreak of COVID-19 has rapidly spread to various national regions. As the number of COVID-19 patients has increased, some of those infected with SARS-CoV-2 have developed a variety of psychiatric symptoms, including depression, cognitive impairment, and fatigue. A distinct storm of inflammatory factors that contribute to the initial disease but also a persistent post-acute phase syndrome has been reported in patients with COVID-19. Neuropsychological symptoms including depression, cognitive impairment, and fatigue are closely related to circulating and local (brain) inflammatory factors. Natural products are currently being examined for their ability to treat numerous complications caused by COVID-19. Among them, ginseng has anti-inflammatory, immune system stimulating, neuroendocrine modulating, and other effects, which may help improve psychiatric symptoms. This review summarizes the basic mechanisms of COVID-19 pneumonia, psychiatric symptoms following coronavirus infections, effects of ginseng on depression, restlessness, and other psychiatric symptoms associated with post-COVID syn-dromes, as well as possible mechanisms underlying these effects.


Assuntos
COVID-19 , Panax , Humanos , Depressão/tratamento farmacológico , COVID-19/complicações , SARS-CoV-2 , Fadiga
8.
Opt Express ; 31(11): 18365-18378, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37381549

RESUMO

Focusing light inside scattering media is a long-sought goal in optics. Time-reversed ultrasonically encoded (TRUE) focusing, which combines the advantages of biological transparency of the ultrasound and the high efficiency of digital optical phase conjugation (DOPC) based wavefront shaping, has been proposed to tackle this problem. By invoking repeated acousto-optic interactions, iterative TRUE (iTRUE) focusing can further break the resolution barrier imposed by the acoustic diffraction limit, showing great potential for deep-tissue biomedical applications. However, stringent requirements on system alignment prohibit the practical use of iTRUE focusing, especially for biomedical applications at the near-infrared spectral window. In this work, we fill this blank by developing an alignment protocol that is suitable for iTRUE focusing with a near-infrared light source. This protocol mainly contains three steps, including rough alignment with manual adjustment, fine-tuning with a high-precision motorized stage, and digital compensation through Zernike polynomials. Using this protocol, an optical focus with a peak-to-background ratio (PBR) of up to 70% of the theoretical value can be achieved. By using a 5-MHz ultrasonic transducer, we demonstrated the first iTRUE focusing using near-infrared light at 1053 nm, enabling the formation of an optical focus inside a scattering medium composed of stacked scattering films and a mirror. Quantitatively, the size of the focus decreased from roughly 1 mm to 160 µm within a few consecutive iterations and a PBR up to 70 was finally achieved. We anticipate that the capability of focusing near-infrared light inside scattering media, along with the reported alignment protocol, can be beneficial to a variety of applications in biomedical optics.

9.
Opt Express ; 31(18): 28999-29011, 2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37710708

RESUMO

The frequency-dependent divergence angle of terahertz (THz) beams is a crucial aspect in understanding the generation and transmission of broadband THz waves. However, traditional beam profiling methods, such as 1D or 2D translation/rotation scanning detection, are time-consuming and wasteful of THz energy, making them unsuitable for fast measurement applications, such as single-shot THz generation and detection. Here, we proposed a simple solution that involves passing the THz beam through a core-anti-resonant reflective (CARR) cavity (e.g., a paper tube). The spatial information of the beam is then recorded into its frequency spectrum, which can be easily detected by a following traditional THz time-domain spectroscopy (TDS) system or a single-shot sampling setup. Our method enables the acquisition of the angular dispersion without repetitive measurements, and represents a significant step forward in fast and efficient achievement of spatial properties of broadband THz beams.

10.
Opt Lett ; 48(3): 704-707, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36723568

RESUMO

Recently, the concept of core-anti-resonant reflection (CARR) has been proposed, greatly expanding the options of cladding materials and morphologies for Fabry-Perot-type (F-P) cavities. For instance, a single-layer tube made of A4 paper can be a precision resonator in the terahertz (THz) band, which seemed counterintuitive before. More importantly, thanks to the involvement of paper-like materials as the cavity plates, it is possible to equip the CARR cavity with the currently popular origami functionality. Following this clue, in this work we combined a simple octagonal paper tube with different origami patterns and realized the programmable adjustment for the distance between two parallel surfaces of the tubular cavity. Accordingly, the combination of the CARR cavity and the origami property offers a new degree of freedom and flexibility to vary the cavity distance, tune the resonant frequency, and explore related applications. For applied examples, we carried out pressure sensing with this foldable structure and achieved a high sensitivity (S = 57.9 kPa-1). Meanwhile, the origami cavity could also act as a THz polarization converter, and the output polarization state of the cavity mode was easily modulated from the original linear to circular polarizations with different chiralities. In future works, besides the pressure-driven method used here, heat and magnetism, etc., can further be employed to tune the CARR cavity, benefiting from four dimensional (4D) or soft-magneto origami materials as the cavity wall.

11.
Molecules ; 28(19)2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37836833

RESUMO

Depression is a mental disorder characterized by low mood, lack of motivation, negative cognitive outlook, and sleep problems. Suicide may occur in severe cases, although suicidal thoughts are not seen in all cases. Globally, an estimated 350 million individuals grapple with depression, as reported by the World Health Organization. At present, drug and psychological treatments are the main treatments, but they produce insufficient responses in many patients and fail to work at all in many others. Consequently, treating depression has long been an important topic in society. Given the escalating prevalence of depression, a comprehensive strategy for managing its symptoms and impacts has garnered significant attention. In this context, nutritional psychiatry emerges as a promising avenue. Extensive research has underscored the potential benefits of a well-rounded diet rich in fruits, vegetables, fish, and meat in alleviating depressive symptoms. However, the intricate mechanisms linking dietary interventions to brain function alterations remain largely unexplored. This review delves into the intricate relationship between dietary patterns and depression, while exploring the plausible mechanisms underlying the impact of dietary interventions on depression management. As we endeavor to unveil the pathways through which nutrition influences mental well-being, a holistic perspective that encompasses multidisciplinary strategies gains prominence, potentially reshaping how we approach and address depression.


Assuntos
Antidepressivos , Transtornos Psicóticos , Humanos , Antidepressivos/uso terapêutico , Transtornos Psicóticos/tratamento farmacológico , Dieta , Alimentos , Estado Nutricional , Depressão/terapia
12.
Soft Matter ; 18(46): 8771-8778, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36349899

RESUMO

The stimuli-responsive self-folding structure is ubiquitous in nature, for instance, the mimosa folds its leaves in response to external touch or heat, and the Venus flytrap snaps shut to trap the insect inside. Thus, modeling self-folding structures has been of great interest to predict the final configuration and understand the folding mechanism. Here, we apply a simple yet effective method to predict the folding angle of the temperature-responsive nanocomposite hydrogel/elastomer bilayer structure manufactured by 3D printing, which facilitates the study of the effect of the inevitable variations in manufacturing and material properties on folding angles by comparing the simulation results with the experimentally measured folding angles. The defining feature of our method is to use thermal expansion to model the temperature-responsive nanocomposite hydrogel rather than the nonlinear field theory of diffusion model that was previously applied. The resulted difference between the simulation and experimentally measured folding angle (i.e., error) is around 5%. We anticipate that our method could provide insight into the design, control, and prediction of 3D printing of stimuli-responsive shape morphing (i.e., 4D printing) that have potential applications in soft actuators, robots, and biomedical devices.


Assuntos
Elastômeros , Hidrogéis , Hidrogéis/química , Elastômeros/química , Nanogéis , Impressão Tridimensional , Temperatura
13.
Environ Sci Technol ; 56(5): 3056-3064, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35133807

RESUMO

Harmful algal blooms formed by fast-growing, ephemeral macroalgae have expanded worldwide, yet there is limited knowledge of their potential ecological consequences. Here, we select intense green tides formed by Ulva prolifera in the Yellow Sea, China, to examine the ecological consequences of these blooms. Using 28-isofucosterol in the surface sediment as a biomarker of green algae, we identified the settlement region of massive floating green algae in the area southeast of the Shandong Peninsula in the southern Yellow Sea. The responses of the phytoplankton assemblage from the deep chlorophyll-a maximum layer were then resolved using high-throughput sequencing. We found striking changes in the phytoplankton community in the settlement region after an intensive green tide in 2016, characterized by a remarkable increase in the abundance of the pelagophyte Aureococcus anophagefferens, the causative species of ecosystem disruptive brown tides. Our study strongly suggests that the occurrence of massive macroalgal blooms may promote blooms of specific groups of microalgae through alteration of the marine environment.


Assuntos
Estramenópilas , Ulva , Proliferação de Células , China , Ecossistema , Eutrofização , Proliferação Nociva de Algas , Fitoplâncton/fisiologia , Estramenópilas/química , Estramenópilas/fisiologia , Ulva/fisiologia
14.
BMC Womens Health ; 22(1): 177, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35570288

RESUMO

BACKGROUND: Menstrual migraine is a particular form of migraine with a significant impact on the quality of life for women afflicted. Presently, no study has reported the quality of life in menstrual migraine patients. This work aims to assess the health-related quality of life and identify its associated factors among Chinese menstrual migraine patients. METHODS: The cross-sectional study group consisted of 109 patients with menstrual migraine, and the control group consisted of 397 female patients with non-menstrual migraine. In total, 506 patients completed questionnaires for demographic and clinical information, the Self-rating Idea of Suicide Scale, the Hamilton Depression Scale, the Hamilton Anxiety Scale, the Headache Impact Test-6, the Perceived Social Support Scale, the Pittsburgh Sleep Quality Index. Health-related quality of life was measured using the 36-Item Short Form Survey. RESULTS: Compared with non-menstrual migraine patients, five dimensions of health-related quality of life were all found to be significantly impaired in menstrual migraine patients. Headache frequency (ß = - 0.218, P = 0.014), the impact of headache on daily life (ß = - 0.270, P = 0.002), depression symptoms (ß = - 0.345, P < 0.001) were significantly associated with physical component summary, depression symptoms (ß = - 0.379, P < 0.001), social support (ß = 0.270, P < 0.001), suicidal ideation (ß = - 0.344, P < 0.001) were closely related to mental component summary. CONCLUSION: Menstrual migraine patients had a significantly poorer health-related quality of life in many domains than non-menstrual migraine patients. Headache frequency, the impact of headache on daily life, depression symptoms, social support, and suicidal ideation were significantly associated with health-related quality of life in menstrual migraine patients. TRIAL REGISTRATION: ChiCTR1800014343. This study was registered prospectively on 7 January 2018 at Chinese Clinical Trial registry. http://www.chictr.org.cn/showproj.aspx?proj=24526.


Assuntos
Transtornos de Enxaqueca , Qualidade de Vida , China , Estudos Transversais , Feminino , Cefaleia/complicações , Humanos , Transtornos de Enxaqueca/complicações , Transtornos de Enxaqueca/diagnóstico , Inquéritos e Questionários
15.
Reprod Domest Anim ; 57(6): 653-664, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35247007

RESUMO

Immunocastration vaccines achieve their effects through neutralization of the endogenous hormone by the humoral antibody produced against the immunized genes, but there is little information regarding cell-mediated immune response on the gonadal function of the immunized model is available. In this study, we used ram as a model animal to identify the cellular immune response in testicular tissues of rams immunized with intranasal KISS1 gene vaccine. The immune castration model was evaluated by sexual behaviours, spermatogenesis and serum hormone profiles after the KISS1 gene immunization. Transcriptome analysis of testicular tissues was carried out to identify the expressions of protein-coding genes involved in cellular immunity. The results showed that we successfully constructed the KISS1 immune castration ram model, in which testicular growth and development, testosterone and kisspeptin-54 levels, and sexual function were suppressed in immunized rams (p < .05). Using Hiseq™ 2000 high sequencing for ram testicular, we identified 21 differentially expressed genes (DEGs) related to cellular immunity, of which, 14 genes were upregulated and seven genes were downregulated in the testis of the immunized group (p < .05). The Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that these differentially expressed genes were enriched in the antigen presentation process mediated by MHC class I and the cytotoxic pathway mediated by natural killer cells. It is concluded that KISS1 gene vaccine induced the cell-mediated immune response in testicular tissue to suppress reproductive activities in rams.


Assuntos
Kisspeptinas , Vacinas , Animais , Imunidade Celular , Kisspeptinas/genética , Masculino , Orquiectomia/métodos , Orquiectomia/veterinária , Carneiro Doméstico , Testículo/fisiologia , Testosterona , Transcriptoma
16.
Int J Mol Sci ; 23(14)2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35887116

RESUMO

Transient receptor potential (TRP) ion channels are cationic permeable proteins located on the plasma membrane. TRPs are cellular sensors for perceiving diverse physical and/or chemical stimuli; thus, serving various critical physiological functions, including chemo-sensation, hearing, homeostasis, mechano-sensation, pain, taste, thermoregulation, vision, and even carcinogenesis. Dysregulated TRPs are found to be linked to many human hereditary diseases. Recent studies indicate that TRP ion channels are not only involved in sensory functions but are also implicated in regulating the biological characteristics of stem cells. In the present review, we summarize the expressions and functions of TRP ion channels in stem cells, including cancer stem cells. It offers an overview of the current understanding of TRP ion channels in stem cells.


Assuntos
Canais de Potencial de Receptor Transitório , Membrana Celular/metabolismo , Humanos , Dor , Sensação/fisiologia , Células-Tronco/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo
17.
Int J Mol Sci ; 23(8)2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35456964

RESUMO

TRPV4 (transient receptor potential vanilloid 4), a calcium permeable TRP ion channel, is known to play a key role in endocytosis. However, whether it contributes to exocytosis remains unclear. Here, we report that activation of TRPV4 induced massive exocytosis in both melanoma A375 cell and heterologous expression systems. We show here that, upon application of TRPV4-specific agonists, prominent vesicle priming from endoplasmic reticulum (ER) was observed, followed by morphological changes of mitochondrial crista may lead to cell ferroptosis. We further identified interactions between TRPV4 and folding/vesicle trafficking proteins, which were triggered by calcium entry through activated TRPV4. This interplay, in turn, enhanced TRPV4-mediated activation of folding and vesicle trafficking proteins to promote exocytosis. Our study revealed a signaling mechanism underlying stimulus-triggered exocytosis in melanoma and highlighted the role of cellular sensor TRPV4 ion channel in mediating ferroptosis.


Assuntos
Ferroptose , Melanoma , Cálcio/metabolismo , Canais de Cálcio , Exocitose/fisiologia , Humanos , Canais de Cátion TRPV/metabolismo
18.
Molecules ; 27(6)2022 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-35335197

RESUMO

An increase in the levels of reactive oxygen species (ROS) and high expression levels of transforming growth factor-ß (TGF-ß) in wound tissue are two major problems for wound repair and scar inhibition. Modulation of the wound microenvironment is considered to be able to overcome these issues. Two possible solutions include the use of cerium oxide nanoparticles (CeO2) as an enzyme-like ROS scavenger and pirfenidone (PFD) as an anti-fibrotic drug to inhibit the expression of TGF-ß. However, CeO2 is easily adsorbed by biological macromolecules and loses its enzyme-like activity. Furthermore, the intracellular delivery of PFD is difficult. Herein, the layer-by-layer method was used to prepare nanocapsules (NCs) with a sophisticated structure featuring PFD at their core and CeO2 in their shell; these NCs were referred to as PFD/CeO2 NCs. PFD/CeO2 NCs were supposed to efficiently achieve intracellular delivery of PFD and successfully scavenged ROS from the microenvironment. Cellular experiments verified that PFD/CeO2 NCs had good biocompatibility, satisfactory cellular uptake, and favorable ROS-scavenging capacity. To be applied directly to the wound, PFD/CeO2 NCs were then adhered to plasma-etched polylactic acid (PLA) fiber membranes to prepare a new wound dressing. Animal experiments further demonstrated that the dressing accelerated the epithelialization of the wound, reduced the levels of ROS and TGF-ß, improved the arrangement and proportion of collagen fibers, and finally, achieved satisfactory wound-repairing and anti-scarring effects. These results provide a new concept for promoting wound repair and preventing scar formation.


Assuntos
Cicatriz , Nanocápsulas , Animais , Bandagens , Cério , Cicatriz/prevenção & controle , Piridonas
19.
Entropy (Basel) ; 24(11)2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36359700

RESUMO

With the massive application of IoT and sensor technologies, the study of lightweight ciphers has become an important research topic. In this paper, an effective lightweight LZUC (lightweight Zu Chongzhi) cipher based on chaotic system is proposed to improve the traditional ZUC algorithm. In this method, a further algorithm is designed for the process of integrating chaos into the lightweighting of ZUC. For the first time, this design introduces the logistic chaotic system into both the LFSR (linear feedback shift register) and nonlinear F-function of the cryptographic algorithm. The improved LZUC algorithm not only achieves a certain effect in lightweighting, but also has good statistical properties and security of the output sequence. To verify the performance of the LZUC cipher, we performed NIST statistical tests and information entropy analysis on its output key streams and discussed the typical attacks on the algorithm's resistance to weak key analysis, guess-determination analysis, time-stored data trade-off analysis, and algebraic analysis. In addition, we completed the design of an image security system using the LZUC cipher. Histogram analysis and correlation analysis are used to analyze both plaintext and ciphertext data. At the end of the article, the plaintext and ciphertext images displayed by LCD can be further visualized to verify the encryption effectiveness of the LZUC cipher.

20.
Nanotechnology ; 32(31)2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33836506

RESUMO

The formation of biofilm is one of the causes of bacterial pathogenicity and drug resistance. Recent studies have reported a variety of anti-biofilm materials and achieved good results. However, it is still very important to develop some materials with wider application scenarios or higher biofilm resistance. In this study, a new method to rapidly synthesize nano silver chloride with anti-biofilm activity is proposed. It is a generalizable method in which bacterial extracellular polysaccharides are used to adsorb silver ions, thereby inhibiting the formation of white large-size silver chloride precipitates, and then ultraviolet light is used to induce the synthesis of small-sized nano silver chloride. A variety of polysaccharides can be utilized in the synthesis of nano silver chloride particles. The generated complex was characterized by XRD, UV-vis, EDX, FTIR and TEM methods. Further, the novel complex was found to show highly effective anti-biofilm and bactericidal activity within the biosafety concentration. In view of the high stability of nano sliver chloride, we propose that the novel nano material has the potential as a long-term antibacterial material.


Assuntos
Cloretos/química , Polissacarídeos/química , Compostos de Prata/química , Prata/química , Células A549 , Biofilmes/efeitos dos fármacos , Linhagem Celular , Precipitação Química , Humanos , Nanopartículas , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA