RESUMEN
Total amount of creatine (Cr) and phosphocreatine, or total creatine (tCr), may have a significant impact on the performance of skeletal muscles. In sports such as bodybuilding, it is popular to take Cr supplements to maintain tCr level. However, no study has explored the quantitative relationship between exercise intensity and the induced change in muscle's tCr. In this well-controlled study, straight-leg plantar flexion with specific load and duration was performed by 10 healthy subjects inside an MRI scanner, immediately followed by 1H MR spectroscopy (MRS) for measuring tCr concentration in gastrocnemius. For repeatability assessment, the experiment was repeated for each subject on two different days. Across all the subjects, baseline tCr was 46.6 ± 2.4 mM, ranging from 40.6 to 50.1 mM; with exercise, tCr significantly decreased by 10.9% ± 1.0% with 6-lb load and 21.0% ± 1.3% with 12-lb load (p < 0.0001). Between two different days, baseline tCr, percentage decrease induced by exercise with a 6-lb and 12-lb load differed by 2.2% ± 2.3%, 11.7% ± 6.0% and 4.9% ± 3.2%, respectively. In conclusion, the proposed protocol of controlled exercise stimulation and MRS acquisition can reproducibly monitor tCr level and its exercise-induced change in skeletal muscles. The measured tCr level is sensitive to exercise intensity, so can be used to quantitatively assess muscle performance or fatigue.
Asunto(s)
Creatina , Ejercicio Físico , Músculo Esquelético , Humanos , Creatina/metabolismo , Masculino , Adulto , Ejercicio Físico/fisiología , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiología , Proyectos Piloto , Femenino , Espectroscopía de Resonancia Magnética/métodos , Adulto Joven , Fosfocreatina/metabolismo , Espectroscopía de Protones por Resonancia Magnética/métodosRESUMEN
Vacuoles in plant cells are the most prominent organelles that harbor distinctive features, including lytic function, storage of proteins and sugars, balance of cell volume, and defense responses. Despite their dominant size and functional versatility, the nature and biogenesis of vacuoles in plants per se remain elusive and several models have been proposed. Recently, we used the whole-cell 3D electron tomography (ET) technique to study vacuole formation and distribution at nanometer resolution and demonstrated that small vacuoles are derived from multivesicular body maturation and fusion. Good sample preparation is a critical step to get high-quality electron tomography images. In this chapter, we provide detailed sample preparation methods for high-resolution ET in Arabidopsis thaliana root cells, including high-pressure freezing, subsequent freeze-substitution fixation, embedding, and serial sectioning.
Asunto(s)
Arabidopsis , Tomografía con Microscopio Electrónico , Vacuolas , Tomografía con Microscopio Electrónico/métodos , Vacuolas/ultraestructura , Vacuolas/metabolismo , Arabidopsis/ultraestructura , Arabidopsis/metabolismo , Raíces de Plantas/ultraestructura , Raíces de Plantas/metabolismo , Imagenología Tridimensional/métodos , Substitución por Congelación/métodos , Biogénesis de OrganelosRESUMEN
Ecological water replenishment is an important measure for conserving water sources and improving the water environment. To explore the evolution and causes of groundwater chemistry after ecological water replenishment in the Jialu River, this study utilized groundwater monitoring data from 2015 to 2019 following ecological water replenishment. Various methods, including Piper's trilinear diagram, Gibbs diagram, principal component analysis, and ion ratio analysis, were employed for research purposes. The results indicate that (1) since the implementation of ecological water replenishment in the Jialu River, there has been a general downwards trend in total dissolved solids (TDS) in groundwater. The dominant cation in groundwater is Ca2+, whereas HCO3- is the dominant anion. The concentration of cations in groundwater has generally decreased, with noticeable reductions in SO42- and Cl- concentrations in the upper reaches of the recharge river contributing to improved groundwater quality. (2) A comparison with 2015 reveals a gradual transition at sampling points from chemical types such as HCO3-Ca·Mg and HCO3·Cl-Ca·Mg to an ecological water replenishment chemical type (HCO3-Ca).
RESUMEN
Meningitis caused by Moraxella osloensis is rare and easily misdiagnosed clinically. Here, we report the first case of meningitis caused by M. osloensis in China by taking advantage of the metagenomic next-generation sequencing technology in cerebrospinal fluid for pathogen screening. In addition, we extend the neurological signs, clinical symptoms, diagnostic methods, and treatment of this rare disease.
Asunto(s)
Meningitis Bacterianas , Moraxella , Infecciones por Moraxellaceae , Humanos , Moraxella/aislamiento & purificación , Moraxella/genética , Infecciones por Moraxellaceae/diagnóstico , Infecciones por Moraxellaceae/tratamiento farmacológico , Infecciones por Moraxellaceae/microbiología , Infecciones por Moraxellaceae/complicaciones , Meningitis Bacterianas/diagnóstico , Meningitis Bacterianas/microbiología , Meningitis Bacterianas/tratamiento farmacológico , Masculino , FemeninoRESUMEN
The ability to freeze and stabilize reaction intermediates in their metastable states and obtain their structural and chemical information with high spatial resolution is critical to advance materials technologies such as catalysis and batteries. Here, we develop an electrified operando-freezing methodology to preserve these metastable states under electrochemical reaction conditions for cryogenic electron microscopy (cryo-EM) imaging and spectroscopy. Using Cu catalysts for CO2 reduction as a model system, we observe restructuring of the Cu catalyst in a CO2 atmosphere while the same catalyst remains intact in air at the nanometer scale. Furthermore, we discover the existence of a single valence Cu (1+) state and C-O bonding at the electrified liquid-solid interface of the operando-frozen samples, which are key reaction intermediates that traditional ex situ measurements fail to detect. This work highlights our novel technique to study the local structure and chemistry of electrified liquid-solid interfaces, with broad impact beyond catalysis.
RESUMEN
BACKGROUND: Dihydroartemisinin (DHA), a derivative and active metabolite of artemisinin, possesses various immunomodulatory properties. However, its role in myasthenia gravis (MG) has not been clearly explored. Here, we investigated the role of DHA in experimental autoimmune myasthenia gravis (EAMG) and its potential mechanisms. METHODS: The AChR97-116 peptide-induced EAMG model was established in Lewis rats and treated with DHA. Flow cytometry was used to assess the release of Th cell subsets and Treg cells, and 16S rRNA gene amplicon sequence analysis was applied to explore the relationship between the changes in the intestinal flora after DHA treatment. In addition, network pharmacology and molecular docking were utilized to explore the potential mechanism of DHA against EAMG, which was further validated in the rat model by immunohistochemical and RT-qPCR for further validation. RESULTS: In this study, we demonstrate that oral administration of DHA ameliorated clinical symptoms in rat models of EAMG, decreased the expression level of Th1 and Th17 cells, and increased the expression level of Treg cells. In addition, 16S rRNA gene amplicon sequence analysis showed that DHA restored gut microbiota dysbiosis in EAMG rats by decreasing Ruminococcus abundance and increasing the abundance of Clostridium, Bifidobacterium, and Allobaculum. Using network pharmacology, 103 potential targets of DHA related to MG were identified, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that PI3K-AKT signaling pathway was related to the treatment of DHA on EAMG. Meanwhile, molecular docking verified that DHA has good binding affinity to AKT1, CASP3, EGFR, and IGF1. Immunohistochemical staining showed that DHA treatment significantly inhibited the phosphorylated expression of AKT and PI3K in the spleen tissues of EAMG rats. In EAMG rats, RT-qPCR results also showed that DHA reduced the mRNA expression levels of PI3K and AKT1. CONCLUSIONS: DHA ameliorated EAMG by inhibiting the PI3K-AKT signaling pathway, regulating CD4+ T cells and modulating gut microbiota, providing a novel therapeutic approach for the treatment of MG.
Asunto(s)
Artemisininas , Microbioma Gastrointestinal , Simulación del Acoplamiento Molecular , Miastenia Gravis Autoinmune Experimental , Ratas Endogámicas Lew , Animales , Microbioma Gastrointestinal/efectos de los fármacos , Artemisininas/farmacología , Artemisininas/uso terapéutico , Ratas , Miastenia Gravis Autoinmune Experimental/tratamiento farmacológico , Miastenia Gravis Autoinmune Experimental/inmunología , Femenino , Disbiosis/tratamiento farmacológico , Disbiosis/inmunología , Transducción de Señal/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/efectos de los fármacos , Fosfatidilinositol 3-Quinasas/metabolismoRESUMEN
Nonylphenol (NP), a main byproduct of nonylphenol polyethoxylates (NPEs) degradation, is prevalent across diverse environmental settings. Given its widespread presence, evaluating the ecological risks associated with NP in coastal waters and sediments is essential for the protection of the marine environment. This study evaluates the acute toxicity of NP on ten representative aquatic species from the Bohai Sea, determining the Aquatic Life Criteria (ALC) through two distinct methods. The Criteria Maximum Concentration (CMC) for NP in seawater was established at 12.0 µg/L, with a Predicted No-Effect Concentration (PNEC) for water at 15.2 µg/L and for sediment at 33.3 µg/kg. Additionally, a tiered ecological risk assessment (ERA) of both surface seawater and sediment in the Bohai Sea revealed significant ecological risks at various sediment sites. These results offer crucial insights for assessing the ecological risks to coastal ecosystem and provide foundational data necessary for informed environmental protection and management strategies.
Asunto(s)
Monitoreo del Ambiente , Fenoles , Agua de Mar , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/análisis , Fenoles/toxicidad , Medición de Riesgo , China , Agua de Mar/química , Animales , Sedimentos Geológicos/química , Organismos Acuáticos/efectos de los fármacos , Ecosistema , Pruebas de Toxicidad AgudaRESUMEN
Salmonella screening is essential to avoid food poisoning. A simple, fast and sensitive colorimetric biosensor was elaborately developed for Salmonella detection on a microfluidic chip through limiting air chambers for precise air control, switching rotary valves for accurate fluid selection, a convergence-and-divergence passive micromixer and an extrusion-and-suction active micromixer for efficient fluid mixing, and immune gold@platinum palladium nanocatalysts for effective signal amplification. The mixture of bacteria, immune magnetic nanobeads and nanocatalysts was first rapidly mixed to form nanobead-bacteria-nanocatalyst conjugates and magnetically separated for enrichment. After washing with water, the conjugates were used to catalyze colorless substrate and blue product was finally analyzed using ImageJ for quantifying bacterial concentration. The finger-actuated microfluidic chip enabled designated control of designated fluids in designated places towards designated directions by simple press-release operations on designated air chambers without any external power. Under optimal conditions, this sensor could detect Salmonella at 45 CFU/mL in 25 min.
RESUMEN
Shape-morphing capabilities are crucial for enabling multifunctionality in both biological and artificial systems. Various strategies for shape morphing have been proposed for applications in metamaterials and robotics. However, few of these approaches have achieved the ability to seamlessly transform into a multitude of volumetric shapes post-fabrication using a relatively simple actuation and control mechanism. Taking inspiration from thick origami and hierarchies in nature, we present a hierarchical construction method based on polyhedrons to create an extensive library of compact origami metastructures. We show that a single hierarchical origami structure can autonomously adapt to over 103 versatile architectural configurations, achieved with the utilization of fewer than 3 actuation degrees of freedom and employing simple transition kinematics. We uncover the fundamental principles governing theses shape transformation through theoretical models. Furthermore, we also demonstrate the wide-ranging potential applications of these transformable hierarchical structures. These include their uses as untethered and autonomous robotic transformers capable of various gait-shifting and multidirectional locomotion, as well as rapidly self-deployable and self-reconfigurable architecture, exemplifying its scalability up to the meter scale. Lastly, we introduce the concept of multitask reconfigurable and deployable space robots and habitats, showcasing the adaptability and versatility of these metastructures.
RESUMEN
Dominant microorganisms and functional genes, including hgcA, hgcB, merA, and merB, have been identified to be responsible for mercury (Hg) methylation or methylmercury (MeHg) demethylation. However, their in situ correlation with MeHg levels and the processes of Hg methylation and MeHg demethylation in coastal areas remains poorly understood. In this study, four functional genes related to Hg methylation and MeHg demethylation (hgcA, hgcB, merA, and merB) were all detected in the sediments of the Eastern China Coastal Seas (ECCSs) (representative coastal seas highly affected by human activities) using metagenomic approaches. HgcA was identified to be the key gene controlling the in situ net production of MeHg in the ECCSs. Based on metagenomic analysis and incubation experiments, sulfate-reducing bacteria were identified as the dominant microorganisms controlling Hg methylation in the ECCSs. In addition, hgcA gene was positively correlated with the MeHg content and Hg methylation rates, highlighting the potential roles of Hg methylation genes and microorganisms influenced by sediment physicochemical properties in MeHg cycling in the ECCSs. These findings highlighted the necessity of conducting similar studies in other natural systems for elucidating the molecular mechanisms underlying MeHg production in aquatic environments.
Asunto(s)
Sedimentos Geológicos , Compuestos de Metilmercurio , Océanos y Mares , Contaminantes Químicos del Agua , Sedimentos Geológicos/microbiología , Compuestos de Metilmercurio/metabolismo , China , Contaminantes Químicos del Agua/metabolismo , Bacterias/metabolismo , Bacterias/genética , Biodegradación Ambiental , Metilación , Mercurio/metabolismo , Genes BacterianosRESUMEN
Mechanical computing encodes information in deformed states of mechanical systems, such as multistable structures. However, achieving stable mechanical memory in most multistable systems remains challenging and often limited to binary information. Here, we report leveraging coupling kinematic bifurcation in rigid cube-based mechanisms with elasticity to create transformable, multistable mechanical computing metastructures with stable, high-density mechanical memory. Simply stretching the planar metastructure forms a multistable corrugated platform. It allows for independent mechanical or magnetic actuation of individual bistable element, serving as pop-up voxels for display or binary units for various tasks such as information writing, erasing, reading, encryption, and mechanologic computing. Releasing the pre-stretched strain stabilizes the prescribed information, resistant to external mechanical or magnetic perturbations, whereas re-stretching enables editable mechanical memory, akin to selective zones or disk formatting for information erasure and rewriting. Moreover, the platform can be reprogrammed and transformed into a multilayer configuration to achieve high-density memory.
RESUMEN
As a typical biomarker of Alzheimer's disease, rapid and specific detection of tau protein can help improve the early diagnosis and prognosis of the disease. In this study, a simple sandwich electrochemical immunosensor was developed for rapid detection of tau protein. Primary monoclonal antibodies (mAb1) against the middle domain of tau protein (amino acids 189-195) were immobilized on the gold electrode surface through a self-assembled monolayer (SAM) of 3,3'-dithiobis (sulfosuccinimidyl propionate) (DTSSP). Then the tau protein was captured through the specific adsorption between the antigen and the antibody, resulting in a change in the impedance. Secondary monoclonal antibodies (mAb2) against the N-terminal region of tau protein were used for further amplification of the binding reaction between mAb1 and tau protein. A linear correlation between the total change in impedance and the logarithm of tau concentration was found from 2 × 10-6 mg mL-1 to 2 × 10-3 mg mL-1, with a detection limit as low as 1 × 10-6 mg mL-1. No significant interference was observed from human serum albumin. Furthermore, the fabricated sandwich immunosensor successfully detected target tau protein in artificial cerebrospinal fluid (aCSF) samples, indicating good potential for clinical applications in the future.
Asunto(s)
Enfermedad de Alzheimer , Biomarcadores , Técnicas Biosensibles , Técnicas Electroquímicas , Proteínas tau , Enfermedad de Alzheimer/diagnóstico , Humanos , Anticuerpos Monoclonales , Oro/química , Inmunoensayo/métodos , Límite de Detección , ElectrodosRESUMEN
Working to simplify mechanistic models on the basis of reliability for estimating crop evapotranspiration (ET) in a greenhouse is still worthwhile for horticulturists. In this study, four ET models (Penman-Monteith, Priestley-Taylor, and Shuttleworth-Wallace models, and the Crop coefficient method) were parameterized after taking the restriction effect of resistance parameters in these models on ET into account, named as PA-PM, PA-PT, PA-CC, and PA-SW, respectively. The performance of these four parameterized models was compared at different growth stages, as well as the entire growing season. Tomatoes that were ET-grown in a solar greenhouse without a heating device were measured using weighting lysimeters during 2016-2017 and 2019-2021, in which data from 2016 were used to adjust the model parameters, and data from the other four study years were used to examine the model performance. The results indicated that the PA-PT and PA-CC models have a better performance in estimating tomato ET at four growth stages, while the PA-PM and PA-SW performed well only at the development and middle stages. Compared to the ET that was measured with the weighting lysimeters, the ET that was predicted using the PA-PM model was 27.0% lower at the initial stage, and 8.7% higher at the late stage; the ET that was computed using the PA-SW model was 19.5% and 13.6% higher at the initial and late stages, respectively. The PA-PT model yielded the lowest root mean square error and the highest index of agreement against the other models over the entire growing season, indicating that the PA-PT model is the best recommended model for estimating tomato ET in a solar greenhouse.
RESUMEN
Developing a high quality ceramic laser gain medium for solar directly pumped solid state lasers is essential, and yet the light conversion efficiency of the gain media for solar pumping remains a challenge. In this study, Ce and Nd ions, co-doped YAG transparent ceramics with theoretical transmittance and stable Ce3+ valent state were developed, and revealed that the absorbed visible light and light conversion efficiency in Ce,Nd:YAG ceramics were 3.98 times and 1.34 times higher than those in widely reported Cr,Nd:YAG ceramics, respectively. A concentration matching principle between Ce3+ and Nd3+ ions in YAG was established, and a higher Nd3+ ion doping concentration with a relatively low Ce3+ concentration was favorable to improve both the light conversion efficiency and emission intensity at 1064â nm of Ce,Nd:YAG ceramics. Energy transfer efficiency from Ce3+ to Nd3+ of the 0.3 at.%Ce,1.5at.%Nd:YAG ceramic reached as high as 61.71% at room temperature. Surprisingly, it was further promoted to 64.31% at a higher temperature of 473â K. More excited electrons at the upper energy level of Ce3+ ion under the high temperature accounted for this novel phenomenon. This study proposes a new design strategy of gain materials for solar directly pumped solid state lasers.
RESUMEN
Coastal wetland soils play a critical role in the global mercury (Hg) cycle, serving as both an important repository for total mercury (THg) and a hotspot for methylmercury (MeHg) production. This study investigated Hg pollution in soils dominated by Phragmites australis (PA) and Spartina alterniflora (SA) across five representative China's coastal wetlands (Yellow River (YR), Linhong River (LHR), Yangtze River (CJR), Min River (MR), and Nanliu River (NLR)). The THg concentrations ranged from 16.7 to 446.0 (96.3 ± 59.3 ng g-1, dw), while MeHg concentrations varied from 0.01 to 0.81 (0.12 ± 0.12 ng g-1, dw). We further evaluated Hg risk in these wetlands using potential ecological risk index (Er) and geographical enrichment factor (Igeo). Most wetlands exhibited low to moderate ecological risk, except the PA habitat in the YR wetland, showing moderate to high risk. Soil organic matter significantly influenced THg and MeHg distribution, while MeHg% correlated well with soil salinity and pH. These findings highlight the importance of organic-rich coastal wetland soils in THg and MeHg accumulation, with the soil properties influencing net MeHg production. Furthermore, SA habitat generally exhibited higher MeHg%, suggesting its invasion elevates the ecological risk of MeHg in coastal wetlands. ENVIRONMENTAL IMPLICATION: Mercury (Hg), a global pollutant, poses great risks to wildlife and humans. Since industrialization, anthropogenic Hg release surpassed natural sources. Long-term exposure leads to biomagnification of Hg. This study assessed Hg and methylmercury pollution and risks in soils of five China's coastal wetlands dominated by Phragmites australis and Spartina alterniflora. Environmental factors (total carbon, total organic carbon, total nitrogen, salinity, pH) were analyzed to reveal key variables influencing Hg pollution and methylation. Essential for quantifying Hg pollution in coastal wetlands, the findings provide a scientific basis for effective wetland conservation policies and addressing environmental health in these regions.
Asunto(s)
Monitoreo del Ambiente , Mercurio , Compuestos de Metilmercurio , Contaminantes del Suelo , Humedales , Compuestos de Metilmercurio/análisis , China , Mercurio/análisis , Contaminantes del Suelo/análisis , Suelo/químicaRESUMEN
Mercury (Hg) emitted from East Asian has increased the risk of Hg in China Marginal Seas for decades. However, the speciation of Hg (especially the bioavailable Hg) in these regions remains unclear. To address this problem, we analyzed total Hg (THg) and methylmercury (MeHg) in the sediment and porewater of Yellow sea (YS) and East China Sea (ECS) and determined the speciation of Hg using both improved BCR sequential extraction and isotope dilution (ID) techniques. Nearshore areas of YS and ECS exhibited higher THg levels in sediments and porewater, suggesting the significant contribution of terrestrial inputs. The spatial distribution of MeHg showed similar trends with THg, but the sites with higher MeHg concentrations did not align with those of THg. The improved BCR sequential extraction method showed the residual fraction dominated Hg content (â¼44 %) in both systems, with a minor bioavailable carbonate fraction (1 %). The Spearman correlation analysis indicates that Eh and pH are the two factors significantly affected Hg bioavailability in the sediment. The bioavailability of Hg (estimated by the BCR method) showed a significant positive correlation with MeHg levels in the sediment (R²=0.47, P < 0.05), suggesting that BCR can be used to estimate the potential of Hg methylation in the sediment. However, the extent of bioavailable Hg in BCR and ID method were 1.15 ± 0.38 % and 29.5 ± 14.8 %, respectively, implying that Hg bioavailability may be underestimated by BCR techniques compared to ID methods (T-test, P < 0.01).
Asunto(s)
Sedimentos Geológicos , Mercurio , Compuestos de Metilmercurio , Contaminantes Químicos del Agua , Sedimentos Geológicos/química , Mercurio/análisis , China , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente/métodos , Disponibilidad Biológica , Océanos y MaresRESUMEN
Background: Inborn errors of metabolism (IEMs) are rare diseases caused by inherited defects in various biochemical pathways that strongly correlate with early neonatal mortality and stunting. Currently, no studies have reported on the incidence of IEMs of multi-ethnic groups in Huaihua, China. Methods: A total of 206,977 neonates with self-reported ethnicity who underwent IEM screening at Huaihua from 2015 to 2021 were selected for observation. Among them, 69 suspected IEM-positive neonates were referred for urine gas chromatography-mass spectrometry analysis, biochemical detection, next-generation sequencing, and Sanger sequencing. Results: Sixty-nine newborns were diagnosed with IEMs, with an overall incidence of 1:3,000. The two most common disorders were 2-methylbutyryl glycinuria (1:7,137) and phenylalanine hydroxylase deficiency (1:22,997). Moreover, the incidence of IEMs in the minority ethnic group (Miao, Dong, Tujia and Yao) (1:1,852) was markedly higher than in the Han ethnic group (1:4,741). Some ethnic features variants were identified; NM_001609.4:c.1165A>G in the ACADSB gene for Miao and Dong ethnic groups, NM_014251.2:c.852_855del in the SLC25A13 gene for Miao ethnic groups. Conclusion: This study revealed the IEM incidence within the minority ethnic groups is markedly higher than among the Han nationality and the gene variant spectrum is dramatically different in Huaihua, China. Hence, It serves as a theoretical reference for the screening and diagnosing of neonatal IEMs of multi-ethnic groups in the Huaihua area, and across China.
RESUMEN
Miniature shape-morphing soft actuators driven by external stimuli and fluidic pressure hold great promise in morphing matter and small-scale soft robotics. However, it remains challenging to achieve both rich shape morphing and shape locking in a fast and controlled way due to the limitations of actuation reversibility and fabrication. Here, fully 3D-printed, sub-millimeter thin-plate-like miniature soft hydraulic actuators with shape memory effect (SME) for programable fast shape morphing and shape locking, are reported. It combines commercial high-resolution multi-material 3D printing of stiff shape memory polymers (SMPs) and soft elastomers and direct printing of microfluidic channels and 2D/3D channel networks embedded in elastomers in a single print run. Leveraging spatial patterning of hybrid compositions and expansion heterogeneity of microfluidic channel networks for versatile hydraulically actuated shape morphing, including circular, wavy, helical, saddle, and warping shapes with various curvatures, are demonstrated. The morphed shapes can be temporarily locked and recover to their original planar forms repeatedly by activating SME of the SMPs. Utilizing the fast shape morphing and locking in the miniature actuators, their potential applications in non-invasive manipulation of small-scale objects and fragile living organisms, multimodal entanglement grasping, and energy-saving manipulators, are demonstrated.
RESUMEN
Coastal seas contribute the majority of human methylmercury (MeHg) exposure via marine fisheries. The terrestrial area surrounding the Bohai Sea and Yellow Sea (BS and YS) is one of the mercury (Hg) emission "hot spots" in the world, resulting in high concentrations of Hg in BS and YS seawater in comparison to other marine systems. However, comparable or even lower Hg levels were detected in seafood from the BS and YS than other coastal regions around the word, suggesting a low system bioaccumulation of Hg. Reasoning a low system efficiency of MeHg production (represented by MeHg/THg (total Hg) in seawater) may be present in these two systems, seven cruises were conducted in the BS and YS to test this hypothesis. MeHg/THg ratios in BS and YS seawater were found to be lower than that in most coastal systems, indicating that the system efficiency of MeHg production is relatively lower in the BS and YS. The low system efficiency of MeHg production reduces the risk of Hg in the BS and YS with high Hg discharge intensity. By measuring in situ production and degradation of MeHg using double stable isotope addition method, and MeHg discharge flux from various sources and its exchange at various interfaces, the budgets of MeHg in the BS and YS were estimated. The results indicate that in situ methylation and demethylation are the major source and sink of MeHg in the BS and YS. By comparing the potential controlling processes and environmental parameters for MeHg/THg in the BS and YS with the other coastal seas, estuaries and bays, lower transport efficiency of inorganic Hg from water column to the sediment, slower methylation of Hg, and rapid demethylation of MeHg were identified to be major reasons for the low system efficiency of MeHg production in the BS and YS. This study highlights the necessity of monitoring the system efficiency of MeHg production, associated processes, and controlling parameters to evaluate the efficiency of reducing Hg emissions in China as well as the other countries.
Asunto(s)
Monitoreo del Ambiente , Compuestos de Metilmercurio , Agua de Mar , Contaminantes Químicos del Agua , Agua de Mar/química , Océanos y Mares , China , MercurioRESUMEN
The coronavirus disease 2019 pandemic highlighted the need for more rapid and routine application of modeling approaches such as quantitative microbial risk assessment (QMRA) for protecting public health. QMRA is a transdisciplinary science dedicated to understanding, predicting, and mitigating infectious disease risks. To better equip QMRA researchers to inform policy and public health management, an Advances in Research for QMRA workshop was held to synthesize a path forward for QMRA research. We summarize insights from 41 QMRA researchers and experts to clarify the role of QMRA in risk analysis by (1) identifying key research needs, (2) highlighting emerging applications of QMRA; and (3) describing data needs and key scientific efforts to improve the science of QMRA. Key identified research priorities included using molecular tools in QMRA, advancing dose-response methodology, addressing needed exposure assessments, harmonizing environmental monitoring for QMRA, unifying a divide between disease transmission and QMRA models, calibrating and/or validating QMRA models, modeling co-exposures and mixtures, and standardizing practices for incorporating variability and uncertainty throughout the source-to-outcome continuum. Cross-cutting needs identified were to: develop a community of research and practice, integrate QMRA with other scientific approaches, increase QMRA translation and impacts, build communication strategies, and encourage sustainable funding mechanisms. Ultimately, a vision for advancing the science of QMRA is outlined for informing national to global health assessments, controls, and policies.