Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.966
Filtrar
1.
Haematologica ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38721728

RESUMO

Not available.

2.
Opt Lett ; 49(10): 2733-2736, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38748148

RESUMO

A novel approach-integrating a simulated annealing (SA) algorithm with deep learning (DL) acceleration-is presented for the rapid and accurate development of terahertz perfect absorbers through forward prediction and backward design. The forward neural network (FNN) effectively deduces the absorption spectrum based on metasurface geometry, resulting in an 80,000-fold increase in computational speed compared to a full-wave solver. Furthermore, the absorber's structure can be precisely and promptly derived from the desired response. The incorporation of the SA algorithm significantly enhances design efficiency. We successfully designed low-frequency, high-frequency, and broadband absorbers spanning the 4 to 16 THz range with an error margin below 0.02 and a remarkably short design time of only 10 min. Additionally, the proposed model in this Letter introduces a novel, to our knowledge, method for metasurface design at terahertz frequencies such as the design of metamaterials across optical, thermal, and mechanical domains.

3.
Psychiatry Res ; 337: 115926, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38733930

RESUMO

The optimal duration of antidepressant treatment for patients with major depressive disorder to reduce the risk of relapse after discontinuation remains uncertain. Medline, Cochrane Central Register of Controlled Trials, and Embase were systematically searched for randomized controlled trials (RCTs) with a discontinuation design. A single-group summary meta-analysis was performed to calculate 6-month relapse rates after discontinuation. Meta-regression with restricted cubic splines was performed to model the non-linear relationship between treatment duration and relapse rate after discontinuation. Thirty-five RCTs were included. The relapse rate after discontinuation was approximately 34.81 % at 6 months and 45.12 % at 12 months. After controlling for covariates, the meta-analysis shows that the duration of treatment is associated with the risk of relapse after discontinuation in a non-linear curve, with a relatively higher risk of relapse observed for a duration of less than three months. There appears to be no further reduction in the risk of relapse when treatment is continued for over six months. Our results indicate the importance of at least three months of treatment to avoid the relatively high risk of relapse after discontinuation. The additional benefit of longer treatment remains to be proven.

4.
Geriatr Gerontol Int ; 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38766995

RESUMO

AIM: Extending working life is considered as an important initiative to respond to the population aging and pension payment dilemma. This study aimed to investigate whether work after retirement is related to improved health-related quality of life. METHODS: We used two waves of data from the China Health and Retirement Longitudinal Study in 2011 and 2018. Work after retirement was ascertained based on self-reported retirement and work status, and health-related quality of life (HRQOL) was measured with the three-level EuroQol five-dimensions. The impact of work after retirement on HRQOL was analyzed using the propensity score matching with difference-in-difference approach. RESULTS: A total of 1043 retirees were included. The results showed that work after retirement was associated with significant improvement in HRQOL among retirees (ß = 0.072, P < 0.001). Heterogeneity analyses did not show specificity on sex (P for sex interaction >0.05), but older-aged retirees seemed more sensitive to the benefits of work after retirement on HRQOL than their younger-aged counterparts (≥65 years: ß = 0.167, P < 0.001 vs <65 years: ß = -0.047, P > 0.05; P for age interaction = 0.010). CONCLUSIONS: Work after retirement shows a positive impact on HRQOL among community-dwelling adults in China. Policy-makers should take the health of retirees into account when implementing policies related to delayed retirement, and reduce health inequity. Geriatr Gerontol Int 2024; ••: ••-••.

5.
Chemistry ; : e202400882, 2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38736029

RESUMO

The triboelectric material is the key factor affecting the performance of triboelectric nanogenerators (TENGs). Inorganic materials have higher heat resistance and stability than widely used organic materials. However, the weaker triboelectric property limits the application of TENGs. Modulating surface roughness by changing particle shape and size is a simple way to increase performance for TENGs. Polyoxometalates (POMs) have unrivalled structural diversity and can self-assemble to form different nanostructures. In this study, we propose [{(NH4)42[Mo72VIMo60VO372(CH3COO)30(H2O)7.ca.300H2O.ca.CH3COONH4)]}-Mo132] and [{Na8K14(VO)2[{(MoVI)(Mo5VIO21)(H2O)3]}10{(MoVI)Mo5VIO21(H2O)3(SO4)}2{VIVO(H2O)20}{VIVO}10({KSO4}5)2]·150H2O)}-Mo72V30] with blackberry structure which are cured and prepared into film by spin-coating technique, are used as triboelectric positive materials for the first time in the field of TENGs. Keplerate-type polyoxometalates can form blackberry structures with higher dispersibility and flexibility, which can be used to control surface roughness by regulating the size of particles. The discovery proves that the particle size influences the surface roughness, which adjusts the output of TENGs. According to our findings, Mo132-h-TENG generates an output voltage of 29.3 V, an output charge of 8 nC 2-3 folds higher than Mo132-TENG, and a maximum power density of 6.25 mW·m-2 at 300 MΩ. Our research provides that altering the dimensional size can be an available way to raise the output of TENGs.

6.
Sci Total Environ ; 933: 173080, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38735320

RESUMO

In light of the pressing need to reduce carbon emissions, the biomass power generation industry has gained significant attention and has increasingly become a crucial focus in China. However, there are still considerable gaps in the historical background, status, and prospects of biomass power generation. Herein, the historical and current status of biomass power generation in China are systematically reviewed, with a particular emphasis on supportive policies, environmental impacts, and future projections. By 2022, the newly installed capacity for biomass power generation reached 3.34 MW with a total installed capacity of 41 MW. The power produced from biomass power generation is 182.4 billion kWh in China. The total installed capacity and generated power in 2022 were 1652 and 1139 folds higher than in 2006 when the first biomass generation plant was established. However, disparities in the distribution of biomass resources and power generation were observed. Key drivers of the industry development include tax, finance, and subsidy policies. Under the implementation of the 14th Five-Year Plan for renewable energy development and the goal of carbon neutrality, biomass power generation may achieve great success through more targeted policy support and advanced technologies that reduce air pollutant emissions. If combined with Bioenergy with Carbon Capture and Storage (BECCS) technology, biomass power generation will make its contribution to carbon neutrality in China.

7.
J Mater Chem B ; 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38699827

RESUMO

Optimizing the antibacterial effectiveness of copper ions while reducing environmental and cellular toxicity is essential for public health. A copper chelate, named PAI-Cu, is skillfully created using a specially designed carboxyl copolymer (a combination of acrylic and itaconic acids) with copper ions. PAI-Cu demonstrates a broad-spectrum antibacterial capability both in vitro and in vivo, without causing obvious cytotoxic effects. When compared to free copper ions, PAI-Cu displays markedly enhanced antibacterial potency, being about 35 times more effective against Escherichia coli and 16 times more effective against Staphylococcus aureus. Moreover, Gaussian and ab initio molecular dynamics (AIMD) analyses reveal that Cu+ ions can remain stable in the carboxyl compound's aqueous environment. Thus, the superior antibacterial performance of PAI-Cu largely stems from its modulation of copper ions between mono- and divalent states within the Cu-carboxyl chelates, especially via the carboxyl ligand. This modulation leads to the generation of reactive oxygen species (˙OH), which is pivotal in bacterial eradication. This research offers a cost-effective strategy for amplifying the antibacterial properties of Cu ions, paving new paths for utilizing copper ions in advanced antibacterial applications.

8.
Cancer Sci ; 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38710213

RESUMO

Circular RNAs (circRNAs) have emerged as crucial regulators in tumor progression, yet their specific role in hepatocellular carcinoma (HCC) remains largely uncharacterized. In this study, we utilized high-transcriptome sequencing to identify the upregulation of circESYT2 (hsa_circ_002142) in HCC tissues. Functional experiments carried out in vivo and in vitro revealed that circESYT2 played a significant role in maintaining the growth and metastatic behaviors of HCC. Through integrative analysis, we identified enolase 2 (ENO2) as a potential target regulated by circESYT2 through the competitive endogenous RNA sponge mechanism. Additional gain- or loss-of-function experiments indicated that overexpression of circESYT2 led to a tumor-promoting effect, which could be reversed by transfection of microRNA-665 (miR-665) mimic or ENO2 knockdown in HCC cells. Furthermore, the direct interaction between miR-665 and circESYT2 and between miR-665 and ENO2 was confirmed using RNA immunoprecipitation, FISH, RNA pull-down, and dual-luciferase reporter assays, highlighting the involvement of the circESYT2/miR-665/ENO2 axis in promoting HCC progression. These findings shed light on the molecular characteristics of circESYT2 in HCC tissues and suggest its potential as a biomarker or therapeutic target for HCC treatment.

9.
Plant Dis ; 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38720535

RESUMO

Cassava (Manihot esculenta) is a perennial crop of the family Euphorbiaceae, widely cultivated due to its phytopharmacological and economic values in China. In November 2022, a leaf spot disease on cassava was observed in Zhanjiang, Guangdong, China (21.17° N, 110.18° E), with 100% disease incidence. About 80 % of leaves were covered with spots on the infected plants. Typical symptoms initially appeared as irregular water-soaked lesions that became brown and whitish with the progress of the disease, lesions gradually expanded and coalesced, causing leaf withering, drying and final fall. Tissues (4 to 5 mm) were excised from the margin of lesions, sterilized in 3% H2O2 solution for 3 min, rinsed three times with sterile water, placed on potato dextrose agar (PDA) medium (containing 50mg/L penicillin), and incubated at 25-28 °C. Ten single hypha isolates with similar morphology were obtained and further purified as single conidium subcultures. The colony was grey whitish with sparse aerial mycelium and colony diameter reached 70.4 mm after four days incubation at 25-28℃ in the dark. Black pycnidia occurring as clusters were spherical or irregular, erumpent at maturity, often with a creamy whitish, conidial cirrus extruding from ostiole after 30-days incubation. Conidiophores were hyaline, smooth, unbranched. Alpha conidia were bi-guttulate, hyaline, ellipsoidal, aseptate, with dimensions of 5.1~7.5×1.9~3.4µm (mean 6.2×2.8 µm, n>50). Beta conidia were abundant, filiform, hyaline, smooth, curved in a hooked shape, with a truncate base and dimensions of 18.5-26.4 × 0.6-1.2µm (mean 23.4 × 1.0 µm, n= 40) . Gamma conidia were not observed. The morphological characteristics were similar to those of Diaporthe ueckeri (Udayanga et al. 2015). The internal transcribed spacer (ITS) region, large subunit (LSU) rRNA sequence, actin (ACT), calmodulin (CAL), histone H3 (HIS), translation elongation factor 1-alpha (TEF1-α), and ß-tubulin (TUB) genes of a representative isolate CCAS-MS-6 (ACCC 35497) were amplified and sequenced using primer pairs: ITS5/ITS4, LR0R/LR5, ACT-512F/ACT-783R, CAL228F/CAL737R, CYLH3F/ H3-1b, EF1-728F/ EF1-986R and Bt2a/Bt2b (Gao et al 2017;Udayanga et al 2014). All sequences were deposited in GenBank (OR361671, OR361672, and OR365605-9). BLAST search showed high similarities with sequences of Diaporthe ueckeri (Tab 1). Maximum likelihood analyses of the concatenated data of CAL, HIS, ITS, TEF and TUB using Mega 11 placed CCAS-MS-6 in the D. ueckeri clade. Thus, the fungus was identified as D. ueckeri. Three one-year old healthy plants were used for pathogenicity tests in pots. Two 15-day old leaves of each plant were cleaned with 75% alcohol, three sites on each leaf were wounded, and sites on one of the leaf were covered with fungal plugs from 15-day-old cultures on PDA, and sites on the other leaf with PDA plugs as a control. All plants were kept at ambient temperature (about 28℃) and covered with plastic bags containing sterile wet cotton to maintain the humidity. Seven days after inoculation, all inoculated sites showed symptoms of necrosis, while control sites showed no symptoms. The same fungus identified on the basis of morphological and molecular criteria was reisolated from symptomatic inoculated leaves. In China, D. ueckeri had been reported to cause diseases on Eucalyptus citriodora, Camellia sinensis, and Michelia shiluensis (Gao et al 2016; Liao et al 2023; Yi et al 2018), this is the first report on M. esculenta. The definition of the disease etiology is a prerequisite to develop effective management strategies.

10.
Cells ; 13(9)2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38727270

RESUMO

Self-renewal and differentiation are two characteristics of hematopoietic stem cells (HSCs). Under steady physiological conditions, most primitive HSCs remain quiescent in the bone marrow (BM). They respond to different stimuli to refresh the blood system. The transition from quiescence to activation is accompanied by major changes in metabolism, a fundamental cellular process in living organisms that produces or consumes energy. Cellular metabolism is now considered to be a key regulator of HSC maintenance. Interestingly, HSCs possess a distinct metabolic profile with a preference for glycolysis rather than oxidative phosphorylation (OXPHOS) for energy production. Byproducts from the cellular metabolism can also damage DNA. To counteract such insults, mammalian cells have evolved a complex and efficient DNA damage repair (DDR) system to eliminate various DNA lesions and guard genomic stability. Given the enormous regenerative potential coupled with the lifetime persistence of HSCs, tight control of HSC genome stability is essential. The intersection of DDR and the HSC metabolism has recently emerged as an area of intense research interest, unraveling the profound connections between genomic stability and cellular energetics. In this brief review, we delve into the interplay between DDR deficiency and the metabolic reprogramming of HSCs, shedding light on the dynamic relationship that governs the fate and functionality of these remarkable stem cells. Understanding the crosstalk between DDR and the cellular metabolism will open a new avenue of research designed to target these interacting pathways for improving HSC function and treating hematologic disorders.


Assuntos
Dano ao DNA , Reparo do DNA , Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/citologia , Humanos , Animais , Instabilidade Genômica , Metabolismo Energético , Fosforilação Oxidativa
11.
Front Mol Biosci ; 11: 1368669, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38577173

RESUMO

Background: Lipid metabolism disorders were observationally associated with chalazion, but the causality of the related circulating metabolites on chalazion remained unknown. Here, we investigated the potential causal relationship between circulating metabolites and chalazion using two-sample Mendelian randomization (MR) analysis. Methods: For the primary analysis, 249 metabolic biomarkers were obtained from the UK Biobank, and 123 circulating metabolites were obtained from the publication by Kuttunen et al. for the secondary analysis. Chalazion summary data were obtained from the FinnGen database. Inverse variance weighted (IVW) is the main MR analysis method, and the MR assumptions were evaluated in sensitivity and colocalization analyses. Results: Two MR analyses results showed that the common metabolite, alanine, exhibited a genetic protective effect against chalazion (primary analysis: odds ratio [OR] = 0.680; 95% confidence interval [CI], 0.507-0.912; p = 0.010; secondary analysis: OR = 0.578; 95% CI, 0.439-0.759; p = 0.00008). The robustness of the findings was supported by heterogeneity and horizontal pleiotropy analysis. Two colocalization analyses showed that alanine did not share a region of genetic variation with chalazion (primary analysis: PPH4 = 1.95%; secondary analysis: PPH4 = 25.3%). Moreover, previous studies have suggested that an increase in the degree of unsaturation is associated with an elevated risk of chalazion (OR = 1.216; 95% CI, 1.055-1.401; p = 0.007), with omega-3 fatty acids (OR = 1.204; 95% CI, 1.054-1.377; p = 0.006) appearing to be the major contributing factor, as opposed to omega-6 fatty acids (OR = 0.850; 95% CI, 0.735-0.982; p = 0.027). Conclusion: This study suggests that alanine and several unsaturated fatty acids are candidate molecules for mechanistic exploration and drug target selection in chalazion.

12.
Comput Struct Biotechnol J ; 24: 213-224, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38572168

RESUMO

The intricate task of precisely segmenting retinal vessels from images, which is critical for diagnosing various eye diseases, presents significant challenges for models due to factors such as scale variation, complex anatomical patterns, low contrast, and limitations in training data. Building on these challenges, we offer novel contributions spanning model architecture, loss function design, robustness, and real-time efficacy. To comprehensively address these challenges, a new U-Net-like, lightweight Transformer network for retinal vessel segmentation is presented. By integrating MobileViT+ and a novel local representation in the encoder, our design emphasizes lightweight processing while capturing intricate image structures, enhancing vessel edge precision. A novel joint loss is designed, leveraging the characteristics of weighted cross-entropy and Dice loss to effectively guide the model through the task's challenges, such as foreground-background imbalance and intricate vascular structures. Exhaustive experiments were performed on three prominent retinal image databases. The results underscore the robustness and generalizability of the proposed LiViT-Net, which outperforms other methods in complex scenarios, especially in intricate environments with fine vessels or vessel edges. Importantly, optimized for efficiency, LiViT-Net excels on devices with constrained computational power, as evidenced by its fast performance. To demonstrate the model proposed in this study, a freely accessible and interactive website was established (https://hz-t3.matpool.com:28765?token=aQjYR4hqMI), revealing real-time performance with no login requirements.

13.
Conserv Biol ; : e14266, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38578127

RESUMO

Survival of the immobile embryo in response to rising temperature is important to determine a species' vulnerability to climate change. However, the collective effects of 2 key thermal characteristics associated with climate change (i.e., rising average temperature and acute heat events) on embryonic survival remain largely unexplored. We used empirical measurements and niche modeling to investigate how chronic and acute heat stress independently and collectively influence the embryonic survival of lizards across latitudes. We collected and bred lizards from 5 latitudes and incubated their eggs across a range of temperatures to quantify population-specific responses to chronic and acute heat stress. Using an embryonic development model parameterized with measured embryonic heat tolerances, we further identified a collective impact of embryonic chronic and acute heat tolerances on embryonic survival. We also incorporated embryonic chronic and acute heat tolerance in hybrid species distribution models to determine species' range shifts under climate change. Embryos' tolerance of chronic heat (T-chronic) remained consistent across latitudes, whereas their tolerance of acute heat (T-acute) was higher at high latitudes than at low latitudes. Tolerance of acute heat exerted a more pronounced influence than tolerance of chronic heat. In species distribution models, climate change led to the most significant habitat loss for each population and species in its low-latitude distribution. Consequently, habitat for populations across all latitudes will shift toward high latitudes. Our study also highlights the importance of considering embryonic survival under chronic and acute heat stresses to predict species' vulnerability to climate change.


Efectos colectivos del aumento de las temperaturas promedio y los eventos de calor en embriones ovíparos Resumen La supervivencia de los embriones inmóviles en respuesta al incremento de temperatura es importante para determinar la vulnerabilidad de las especies al cambio climático. Sin embargo, los efectos colectivos de dos características térmicas claves asociadas con el cambio climático (i. e., aumento de temperatura promedio y eventos de calor agudo) sobre la supervivencia embrionaria permanecen en gran parte inexplorados. Utilizamos mediciones empíricas y modelos de nicho para investigar cómo el estrés térmico crónico y agudo influye de forma independiente y colectiva en la supervivencia embrionaria de los lagartos en todas las latitudes. Recolectamos y criamos lagartos de cinco latitudes e incubamos sus huevos en un rango de temperaturas para cuantificar las respuestas específicas de la población al estrés por calor crónico y agudo. Posteriormente, mediante un modelo de desarrollo embrionario parametrizado con mediciones de tolerancia embrionaria al calor, identificamos un impacto colectivo de las tolerancias embrionarias al calor agudo y crónico en la supervivencia embrionaria. También incorporamos la tolerancia embrionaria crónica y aguda al calor en modelos de distribución de especies híbridas para determinar los cambios de distribución de las especies bajo el cambio climático. La tolerancia embrionaria al calor crónico (T­crónico) permaneció constante, mientras que la tolerancia al calor agudo (T­agudo) fue mayor en latitudes altas que en latitudes bajas. La tolerancia al calor agudo ejerció una influencia más pronunciada que la tolerancia al calor crónico. En los modelos de distribución de especies, el cambio climático provocó la pérdida de hábitat más significativa para cada población y especie en su distribución de latitudes bajas. En consecuencia, el hábitat para poblaciones en todas las latitudes se desplazará a latitudes altas. Nuestro estudio también resalta la importancia de considerar la supervivencia embrionaria bajo estrés térmico crónico y agudo para predecir la vulnerabilidad de las especies al cambio climático.

14.
J Colloid Interface Sci ; 666: 594-602, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38613981

RESUMO

Tailoring the omnidirectional conductivity networks in nickel oxide-based electrodes is important for ensuring their long lifespan, stability, high capacity, and high-rate capability. In this study, nickel metal nanoparticles and a three-dimensional nitrogen-doped carbon matrix were used to embellish the nickel oxide composite NiO-Ni/N-C via simplified hard templating. When a porous nitrogen-doped carbon matrix is present, a rapid pathway would be established for charging and discharging the electrons and lithium ions in a lithium-ion battery, thereby alleviating the volumetric expansion of the NiO nanoparticles during the operation of the battery. Moreover, the Ni0 ions added to serve as active sites to improve the capacity of the NiO-based electrodes and strengthen their conductivities. The multielement-effects of the optimal NiO-Ni/N-C electrode leads it to exhibit a capacity of 1310.8 mAh g-1 at 0.1 A g-1 for 120 loops and a rate capability of 441.5 mAh g-1 at 20.0 A g-1. Kinetic analysis of the prepared electrodes proved their ultrafast ionic and electronic conductivities. This strategy of hard templating reduces the number of routes required for preparing different types of electrodes, including NiO-based electrodes, and improves their electrochemical performance to enable their use in energy storage applications.

15.
RSC Adv ; 14(17): 11775-11783, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38617571

RESUMO

Organic piezoelectric materials are emerging as integral components in the development of advanced implantable self-powered sensors for the next generation. Despite their promising applications, a key limitation lies in their reduced mechanical force-to-electricity conversion efficiency. In this study, we present a breakthrough in the fabrication of soft poly(vinylidene fluoride) (PVDF) organic electrospun piezoelectric nanofibers (OEPNs) with exceptional piezoelectric performance achieved through the incorporation of zinc oxide nanorods (ZnO NR). The inclusion of ZnO NR proved instrumental in augmenting the nanocrystallization of PVDF organic electrospun piezoelectric nanofibers (OEPNs), leading to a highly efficient crystal phase transformation from the α phase to the ß/γ phase, serving as superior piezoelectric working dipoles. The resulting PVDF/ZnO NR OEPNs exhibited unparalleled piezoelectric output voltage and current density, particularly noteworthy under a micro-pressure of 1 kPa and a low frequency of 1.5 Hz. Utilizing the obtained PVDF/ZnO NR OEPNs as the piezoelectric working element, we engineered a soft self-powered micro-pressure sensor. This sensor was implanted simultaneously on the cardiovascular walls of the heart and femoral artery in pigs. The sensor demonstrated precise monitoring and recording capabilities for micro-pressure changes during various physiological states, spanning from wakefulness to coma, euthanasia, and notably, the formation of cardiac thrombus. These findings underscore the immense potential of the implantable self-powered sensor for the assessment and diagnosis of pressure-related cardiovascular diseases, such as thrombus and atherosclerosis, during the postoperative recovery phase. This innovative technology offers valuable insights into the dynamic physiological states, paving the way for enhanced postoperative care and management of cardiovascular conditions.

16.
Environ Int ; 186: 108641, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38621323

RESUMO

People generally spend most of their time indoors, making a comprehensive evaluation of air pollution characteristics in various indoor microenvironments of great significance for accurate exposure estimation. In this study, field measurements were conducted in Kunming City, Southwest China, using real-time PM2.5 sensors to characterize indoor PM2.5 in ten different microenvironments including three restaurants, four public places, and three household settings. Results showed that the daily average PM2.5 concentrations in restaurants, public spaces, and households were 78.4 ± 24.3, 20.1 ± 6.6, and 18.0 ± 4.3 µg/m3, respectively. The highest levels of indoor PM2.5 in restaurants were owing to strong internal emissions from cooking activities. Dynamic changes showed that indoor PM2.5 levels increased during business time in restaurants and public places, and cooking time in residential kitchens. Compared with public places, restaurants generally exhibit more rapid increases in indoor PM2.5 due to cooking activities, which can elevate indoor PM2.5 to high levels (5.1 times higher than the baseline) in a short time. Furthermore, indoor PM2.5 in restaurants were dominated by internal emissions, while outdoor penetration contributed mostly to indoor PM2.5 in public places and household settings. Results from this study revealed large variations in indoor PM2.5 in different microenvironments, and suggested site-specific measures for indoor PM2.5 pollution alleviation.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Monitoramento Ambiental , Material Particulado , Poluição do Ar em Ambientes Fechados/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Material Particulado/análise , China , Poluentes Atmosféricos/análise , Humanos , Cidades , Culinária , Restaurantes/estatística & dados numéricos , Tamanho da Partícula
17.
Small ; : e2402438, 2024 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-38644689

RESUMO

The simple and low-cost construction of a 3D network structure is an ideal way to prepare high-performance electromagnetic wave (EMW) absorption materials. Herein, a series of carbon skeleton/carbon nanotubes/Ni3ZnC0.7 composites (CS/CNTs/Ni3ZnC0.7) are successfully prepared by in situ growth of Ni3ZnC0.7 and CNTs on 3D melamine sponge carbon. With the increase of precursor, Ni3ZnC0.7 nanoparticles nucleate and catalyze the generation of CNTs on the surface of the carbon skeleton. The minimum reflection loss (RL) value of the S60min composite (loading time of 60 min) reaches -86.6 dB at 1.6 mm and effective absorption bandwidth (EAB, RL≤-10 dB) is up to 9.3 GHz (8.7-18 GHz). The 3D network sponge carbon with layered micro/nanostructure and hollow skeleton promotes multiple reflection and absorption mechanisms of incident EMW. The N-doping and defects can be equivalent to an electric dipole, providing dipole polarization to increase dielectric relaxation. The uniform Ni3ZnC0.7 nanoparticles and CNTs play a key role in dissipating electromagnetic energy, blocking heat transfer, and enhancing the mechanical properties of the skeleton. Fortunately, the composite displays a quite low thermal conductivity of 0.09075 W m·K-1 and good flexibility, which can provide insulation and quickly recover to its original state after being stressed.

18.
Angew Chem Int Ed Engl ; : e202402546, 2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38616162

RESUMO

Phenylethanoid glycosides (PhGs) exhibit a multitude of structural variations linked to diverse pharmacological activities. Assembling various PhGs via multienzyme cascades represents a concise strategy over traditional synthetic methods. However, the challenge lies in identifying a comprehensive set of catalytic enzymes. This study explores biosynthetic PhG reconstruction from natural precursors, aiming to replicate and amplify their structural diversity. We discovered 12 catalytic enzymes, including four novel 6'-OH glycosyltransferases and three new polyphenol oxidases, revealing the intricate network in PhG biosynthesis. Subsequently, the crystal structure of CmGT3 (2.62 Å) was obtained, guiding the identification of conserved residue 144# as a critical determinant for sugar donor specificity. Engineering this residue in PhG glycosyltransferases (FsGT61, CmGT3, and FsGT6) altered their sugar donor recognition. Finally, a one-pot multienzyme cascade was established, where the combined action of glycosyltransferases and acyltransferases boosted conversion rates by up to 12.6-fold. This cascade facilitated the reconstruction of 26 PhGs with conversion rates ranging from 5-100 %, and 20 additional PhGs detectable by mass spectrometry. PhGs with extra glycosyl and hydroxyl modules demonstrated notable liver cell protection. This work not only provides catalytic tools for PhG biosynthesis, but also serves as a proof-of-concept for cell-free enzymatic construction of diverse natural products.

20.
Int J Biol Macromol ; 268(Pt 1): 131622, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38636762

RESUMO

Separator is an essential component of lithium-ion batteries (LIBs), which is placed between the electrodes to impede their electrical contact and provide the transport channels for lithium ions. Traditionally, the separator contributes the overall mass of LIBs, thereby reducing the gravimetric capacity of the devices. Herein, a dual-layer redox-active cellulose separator is designed and fabricated to enhance the electrochemical performances of LIBs by introducing NiS. The presented separator is composed of an insulating bacterial cellulose (BC) nanofiber layer and a conductive, and redox-active NiS@BC/carbon nanotubes layer. By using the NiS@BC separator, the discharge capacity of the LiFePO4//Li half battery is enhanced to 117 mAh g-1 at a current of 2C owing to the redox-activity of NiS. Moreover, the functional separator-electrode interface can facilitate the homogenous Li stripping/plating and depress the polarization upon the repeated stripping/plating process. Consequently, the battery containing the redox-active separator exhibits outstanding cycle stability and rate capability. The present study contributes a novel strategy for the developments of functional separators to improve the electrochemical properties of LIBs.


Assuntos
Celulose , Fontes de Energia Elétrica , Eletrodos , Lítio , Nanofibras , Oxirredução , Lítio/química , Nanofibras/química , Celulose/química , Celulose/análogos & derivados , Nanotubos de Carbono/química , Íons/química , Técnicas Eletroquímicas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA