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Blastocystis is one of the most common zoonotic intestinal protozoa with global distribution and can cause gastrointestinal syndrome mainly characterized by diarrhea. School children are the main susceptible population. No epidemiological data on Blastocystis among school children in Hainan, the only tropical island province in China. Between March 2021 and June 2023, 1973 fecal samples were collected from school children across three regions in Hainan province. Blastocystis was examined by amplifying the small subunit ribosomal RNA (SSU rRNA) gene via polymerase chain reaction (PCR), and subtypes were identified through DNA sequencing and phylogenetic analysis. The overall prevalence of Blastocystis was 7.3 % (144/1973). The differences in infection rates across different regions, nationalities, and educational stages are statistically significant (P < 0.001). Five subtypes were identified, of which ST3 was the dominant subtype (60.4 %; 87/144), followed by ST1 (27.8 %; 40/144), ST7 (10.4 %; 15/144), ST6 (0.7 %; 1/144), and ST2 (0.7 %; 1/144). 42 known sequences and 15 novel sequences were identified including eight new variations of the ST1 (ST1-16â¼ST1-23) with similarities ranging from 98.3 % to 99.78 % and seven new variations of the ST7 (ST7-7â¼ST7-13) with similarities ranging from 97.7 % to 99.79 % by intra-subtype genetic polymorphisms analysis. The results evaluate the public health risks of Blastocystis among school children in Hainan and the sources of infection were discussed, providing important basic data for the effective prevention and control of intestinal parasitic diseases in Hainan.
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Traditional mining practices not only cause severe environmental issues, but also face the problem of insufficient production capacity of gold to meet its growing demand. The proposed alternative strategies for gold production, such as the extraction of gold from seawater, still keep a formidable challenge due to their strong dependence on adsorbent materials with high capacity, selectivity, and sensitivity, while also needing to meet the demands of being environmentally friendly and cost-effective. In practice, the direct extraction of gold from seawater is limited by its extremely low yield and high energy expenditure. However, if the combination of gold extraction techniques with seawater desalination can substantially reduce the energy consumption, the extraction of gold from seawater will become economical and feasible. In this paper, we evaluate the feasibility of marine gold extraction using reduced graphene oxide membranes (rGOM) during the seawater desalination process. The rGOM can adsorb almost all Au3+ from the solutions with trace concentrations of Au3+ ranging from 10 ppb to 200 ppb. The adsorption quantity is linearly related to the concentration, indicating that the adsorption capacity of rGOM is much higher than the total amount of Au3+ in the solution. Additionally, the rGOM can selectively adsorb 99 % of Au3+ in the mixed solution while hardly adsorbing other common elements in seawater. More importantly, the rGOM exhibits the long-term stability over 30 days when being immersed in the solution, making it directly compatible with the existing seawater desalination processes. These specific properties allow the rGOM to be an ideal candidate for combining the extraction of gold from seawater with seawater desalination processes. Our findings provide a methodology for enhancing the economic efficiency of the extraction of gold from seawater and hold promise for addressing the problem of gold scarcity.
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Transcranial ultrasound imaging presents a significant challenge due to the intricate interplay between ultrasound waves and the heterogeneous human skull. The skull's presence induces distortion, refraction, multiple scattering, and reflection of ultrasound signals, thereby complicating the acquisition of high-quality images. Extracting reflections from the entire waveform is crucial yet exceedingly challenging, as intracranial reflections are often obscured by strong amplitude direct waves and multiple scattering. In this paper, a multiple wave suppression method for ultrasound plane wave imaging is proposed to mitigate the impact of skull interference. Drawing upon prior research, we developed an enhanced high-resolution linear Radon transform using the maximum entropy principle and Bayesian method, facilitating wavefield separation. We detailed the process of wave field separation in the Radon domain through simulation of a model with a high velocity layer. When plane waves emitted at any steering angles, both multiple waves and first arrival waves manifested as distinct energy points. In the brain simulation, we contrasted the characteristic differences between skull reflection and brain-internal signal in Radon domain, and demonstrated that multiples suppression method reduces side and grating lobe levels by approximately 30 dB. Finally, we executed in vitro experiments using a monkey skull to separate weak intracranial reflection signals from strong skull reflections, enhancing the contrast-to-noise ratio by 85 % compared to conventional method using full waveform. This study deeply explores the effect of multiples on effective signal separation, addresses the complexity of wavefield separation, and verifies its efficacy through imaging, thereby significantly advancing ultrasound transcranial imaging techniques.
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Glioblastoma (GBM), as the most common primary brain tumor, usually results in an extremely poor prognosis, in which glioma stem cells (GSCs) and their immunosuppressive microenvironment prominently intervene in the resistance to radiotherapy and chemotherapy that directly leads to tumor recurrence and shortened survival time. The specific mechanism through which exosomes generated from GSCs support the creation of an immunosuppressive microenvironment remains unknown, while it is acknowledged to be engaged in intercellular communication and the regulation of the glioma immunosuppressive microenvironment. The elevated expression of LncRNA-NEAT1 was found in glioma cells after radiotherapy, chemotherapy, and DNA damage stimulation, and NEAT1 could promote the malignant biological activities of GSCs. Emerging evidence suggests that lncRNAs may reply to external stimuli or DNA damage by playing a role in modulating different aspects of tumor biology. Our study demonstrated a promotive role of the carried NEAT1 by GSC-derived exosomes in the polarization of M2-like macrophages. Further experiments demonstrated the mediative role of miR-125a and its target gene STAT3 in NEAT1-induced polarization of M2-like macrophages that promote glioma progression. Our findings elucidate the mechanism by which GSCs influence the polarization of M2-like macrophages through exosomes, which may contribute to the formation of immunosuppressive microenvironments. Taken together, our study reveals the miR-125a-STAT3 pathway through which exosomal NEAT1 from treatment-resistant GSCs contributes to M2-like macrophage polarization, indicating the potential of exosomal NEAT1 for treating glioma.
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PURPOSE: The study was to investigate the association between urinary cadmium with cardiac infarction/injury score (CIIS) and subclinical myocardial injury (SC-MI) in the general population without cardiovascular diseases (CVDs) and chronic kidney disease (CKD). METHODS: In this large-scale cross-sectional study, we enrolled 4492 individuals without CVDs and CKD from the third National Health and Nutrition Examination Survey. Logistic regression models, linear regression models, subgroup analyses, and restricted cubic spline (RCS) were performed to assess the association between urinary cadmium with CIIS and SC-MI. RESULTS: Participants with SC-MI had higher levels of urinary cadmium compared with those without SC-MI (P < 0.001). In multivariate regression analyses adjusting for all confounding variables, higher levels of urinary cadmium were strongly associated not only with higher risk of SC-MI but also with higher CIIS (P < 0.05). Further subgroup analyses showed that the association between urinary cadmium and SC-MI remained significant in the subgroups of ≥ 50 years, men, smokers, and those without diabetes or hypertension (P < 0.05). Additionally, RCS analysis showed that after adjusting for all confounding factors, urinary cadmium was linearly and positively associated with CIIS and SC-MI (P overall < 0.05, P for nonlinearity > 0.05). CONCLUSION: Urinary cadmium was linearly and positively associated with CIIS and SC-MI in the general population without CVDs and CKD.
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Doenças Cardiovasculares , Infarto do Miocárdio , Insuficiência Renal Crônica , Masculino , Humanos , Cádmio , Inquéritos Nutricionais , Estudos Transversais , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/diagnósticoRESUMO
A fully-sampled two-dimensional (2D) matrix array ultrasonic transducer is essential for fast and accurate three-dimensional (3D) volumetric ultrasound imaging. However, these arrays, usually consisting of thousands of elements, not only face challenges of poor performance and complex wiring due to high-density elements and small element sizes but also put high requirements for electronic systems. Current commercially available fully-sampled matrix arrays, dividing the aperture into four fixed sub-apertures to reduce system channels through multiplexing are widely used. However, the fixed sub-aperture configuration limits imaging flexibility and the gaps between sub-apertures lead to reduced imaging quality. In this study, we propose a high-performance multiplexed matrix array by the design of 1-3 piezocomposite and gapless sub-aperture configuration, as well as optimized matching layer materials. Furthermore, we introduce a sub-aperture volumetric imaging method based on the designed matrix array, enabling high-quality and flexible 3D ultrasound imaging with a low-cost 256-channel system. The influence of imaging parameters, including the number of sub-apertures and steering angle on imaging quality was investigated by simulation, in vitro and in vivo imaging experiments. The fabricated matrix array has a center frequency of 3.4 MHz and a -6 dB bandwidth of above 70%. The proposed sub-aperture volumetric imaging method demonstrated a 10% improvement in spatial resolution, a 19% increase in signal-to-noise ratio, and a 57.7% increase in contrast-to-noise ratio compared with the fixed sub-aperture array imaging method. This study provides a new strategy for high-quality volumetric ultrasound imaging with a low-cost system.
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Imageamento Tridimensional , Transdutores , Ultrassonografia/métodos , Razão Sinal-Ruído , Eletrônica , Imagens de FantasmasRESUMO
Luminescent metal clusters have attracted great interest in current research; however, the design synthesis of Al clusters with color-tunable luminescence remains challenging. Herein, an [Al8 (OH)8 (NA)16 ] (Al8 , HNA = nicotinic acid) molecular cluster with dual luminescence properties of fluorescence and room-temperature phosphorescence (RTP) is synthesized by choosing HNA ligand as phosphor. Its prompt photoluminescence (PL) spectrum exhibits approximately white light emission at room temperature. Considering that halogen atoms can be used to regulate the RTP property by balancing the singlet and triplet excitons, different CdX2 (X- = Cl- , Br- , I- ) are introduced into the reactive system of the Al8 cluster, and three new Al8 cluster-based metal-organic frameworks, {[Al8 Cd3 Cl5 (OH)8 (NA)17 H2 O]·2HNA}n (CdCl2 -Al8 ), {[Al8 Cd4 Br7 (OH)8 (NA)16 CH3 CN]·NA·HNA}n (CdBr2 -Al8 ) and {[Al8 Cd8 I16 (OH)8 (NA)16 ]}n (CdI2 -Al8 ) are successfully obtained. They realize the color tunability from blue to yellow at room temperature. The origination of fluorescence and phosphorescence has also been illustrated by structure-property analysis and theoretical calculation. This work provides new insights into the design of multicolor luminescent metal cluster-based materials and develops advanced photo-functional materials for multicolor display, anti-counterfeiting, and encryption applications.
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Coherent plane-wave compounding technique enables rapid ultrasound imaging with comparable image quality to traditional B-mode imaging that relies on focused beam transmission. However, existing methods assume homogeneity in the imaged medium, neglecting the heterogeneity in sound velocities and densities present in real tissues, resulting in noise reverberation. This study introduces the Reverse Time Migration (RTM) method for ultrasound plane-wave imaging to overcome this limitation, which is combined with a method for estimating the speed of sound in layered media. Simulation results in a homogeneous background demonstrate that RTM reduces side lobes and grating lobes by approximately 30 dB, enhancing the contrast-to-noise ratio by 20% compared to conventional delay and sum (DAS) beamforming. Moreover, RTM achieves superior imaging outcomes with fewer compounding angles. The lateral resolution of the RTM with 5-9 angle compounding is able to achieve the effectiveness of the DAS method with 15-19 angle compounding, and the CNR of the RTM with 11-angle compounding is almost the same as that of the DAS with 21-angle compounding. In a heterogeneous background, experimental simulations and in vitro wire phantom experiments confirm RTM's capability to correct depth imaging, focusing reflected waves on point targets. In vitro porcine tissue experiments enable accurate imaging of layer interfaces by estimating the velocities of multiple layers containing muscle and fat. The proposed imaging procedure optimizes velocity estimation in complex media, compensates for the impact of velocity differences, provides more reliable imaging results.
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Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Ultrassonografia , Ultrassonografia/métodos , Animais , Suínos , Processamento de Imagem Assistida por Computador/métodos , Algoritmos , Simulação por Computador , Processamento de Sinais Assistido por ComputadorRESUMO
The present study aimed to shed light on the effects of altitudes and three cooking methods (boiling, steaming, and roasting) on the physicochemical quality, volatile profile, and sensorial characteristics of yak meat. Composite meat samples were prepared to represent each cooking method and altitude level from the longissimus thoracis et lumborum (LTL) muscle of nine yaks. The techniques employed were gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose) along with chemometrics analysis to study the changes occurring in yak volatile profile, and TBARS measurement in lipid oxidation during cooking. Among the cooking methods, boiling and steaming exhibited higher protein and fat content while lower volatile compound contents. Additionally, roasted yak meat received the highest sensory scores, along with decreased L*-values, while elevated a*- and b*-values, and tenderness. A total of 138 volatile compounds were detected, and among them, 36 odorants were identified as odor-active compounds in cooked yak meat. It is evidenced that low-altitude yak presented more complex and richer flavor profiles than high-altitude ones. Moreover, yak meat from low- and high-altitude was classified into two groups by an electronic nose (E-nose) owing to distinct flavor characteristics. Overall, roasted yak meat originating from low altitudes tends to be more popular from a sensory perspective.
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Blastocystis sp. is an important gastrointestinal parasite with global distribution, prevalent in humans, farmed animals, and wildlife. Therefore, this study aimed to investigate the prevalence and genetic diversity of Blastocystis sp. in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) in Hainan Province, China. A total of 900 fecal samples were collected from three farmed animal species including 257 porcupines, 360 rats, and 283 civets. Genomic DNA was extracted from each fecal sample and Blastocystis sp. was detected by PCR at the small subunit ribosomal RNA (SSU rRNA) gene. A phylogenetic tree was constructed using the maximum likelihood method. Blastocystis sp. was detected in 47 (5.2%) fecal samples: 12 (4.7%) Asiatic brush-tailed porcupines, 8 (2.2%) bamboo rats, and 27 (9.5%) masked palm civets. Three known Blastocystis sp. subtypes, including ST1, ST4, ST5, and one unnamed subtype (unST), were found in one, 19, 26, and one animal, respectively. Subtypes ST4 and unST were detected in porcupines, ST4 in rats, and ST1 and ST5 in civets. Our results suggest that the three farmed animal species reported in this study could serve as reservoirs for potentially zoonotic Blastocystis sp. subtypes and transmit this parasite to humans, other farmed animals, and wildlife.
Title: Prévalence et répartition des sous-types de Blastocystis chez les athérures à longue queue (Atherurus macrourus), les rats des bambous (Rhizomys pruinosus) et les civettes masquées (Paguma larvata) élevés en Chine dans le Hainan. Abstract: Blastocystis sp. est un parasite gastro-intestinal important avec une distribution mondiale, répandu chez les humains, les animaux d'élevage et la faune. Par conséquent, cette étude visait à étudier la prévalence et la diversité génétique de Blastocystis sp. chez les athérures à longue queue (Atherurus macrourus), les rats des bambous (Rhizomys pruinosus) et les civettes masquées (Paguma larvata) dans la province de Hainan, en Chine. Au total, 900 échantillons fécaux ont été collectés sur ces trois espèces animales d'élevage dont 257 athérures, 360 rats et 283 civettes. L'ADN génomique a été extrait de chaque échantillon fécal et Blastocystis sp. a été détecté par PCR au niveau du gène de la petite sous-unité de l'ARN ribosomal. Un arbre phylogénétique a été construit en utilisant la méthode du maximum de vraisemblance. Blastocystis sp. a été détecté dans 47 (5,2 %) échantillons fécaux : 12 (4,7 %) athérures, 8 (2,2 %) rats et 27 (9,5 %) civettes. Trois sous-types de Blastocystis sp., dont ST1, ST4, ST5 et un sous-type sans nom (unST), ont été trouvés respectivement chez 1, 19, 26 et 1 animal. Les sous-types ST4 et unST ont été détectés chez les athérures, ST4 chez les rats et ST1 et ST5 chez les civettes. Nos résultats suggèrent que les trois espèces animales d'élevage concernées par cette étude pourraient servir de réservoirs à des sous-types potentiellement zoonotiques de Blastocystis sp. et transmettre ce parasite aux humains, à d'autres animaux d'élevage et à la faune.
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Infecções por Blastocystis , Blastocystis , Porcos-Espinhos , Animais , Humanos , Blastocystis/genética , Infecções por Blastocystis/epidemiologia , Viverridae , Prevalência , Filogenia , Variação Genética , Animais Selvagens , China/epidemiologia , Fezes/parasitologiaRESUMO
The recovery of gold from water is an important research area. Recent reports have highlighted the ultrahigh capacity and selective extraction of gold from electronic waste using reduced graphene oxide (rGO). Here, we made a further attempt with the thermal rGO membranes and found that the thermal rGO membranes also had a similarly high adsorption efficiency (1.79 g gold per gram of rGO membranes at 1000 ppm). Furthermore, we paid special attention to the detailed selectivity between Au3+ and other ions by rGO membranes. The maximum adsorption capacity for Au3+ ions was about 16 times that of Cu2+ ions and 10 times that of Fe3+ ions in a mixture solution with equal proportions of Au3+/Cu2+ and Au3+/Fe3+. In a mixed-ion solution containing Au3+:Cu2+:Na+:Fe3+:Mg2+ of printed circuit board (PCB), the mass of Au3+:Cu2+:Na+:Fe3+:Mg2+ in rGO membranes is four orders of magnitude higher than the initial mass ratio. A theoretical analysis indicates that this selectivity may be attributed to the difference in the adsorption energy between the metal ions and the rGO membrane. The results are conducive to the usage of rGO membranes as adsorbents for Au capture from secondary metal resources in the industrial sector.
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Studies on the spatio-temporal variation and driving mechanism of PM2.5 concentration in the Chengdu-Chongqing urban agglomeration are of great significance for regional atmospheric environment protection and national economic sustainable development. Based on PM2.5 remote sensing data, DEM data, in situ meteorological data, MODIS NDVI data, population density data, nighttime lighting data, road network data, and land use type data, a series of mathematical methods such as Theil-Sen Medium analysis and Mann-Kendall significance test, combined with the Geo-detector model were used to analyze the spatio-temporal variation and multi-dimensional detection of the driving mechanism of PM2.5 concentration in the Chengdu-Chongqing urban agglomeration. The results showed that the overall PM2.5 concentration showed a fluctuating downward trend in the Chengdu-Chongqing urban agglomeration from 2000 to 2021, and the PM2.5 pollution was the most prominent in winter. PM2.5 concentration exhibited obvious spatial heterogeneity with "high in the middle and low in the surrounding areas." The high-PM2.5 concentration areas were mainly concentrated in Zigong, Neijiang, Ziyang, and Guang'an, and the areas with a PM2.5 concentration decrease were mainly concentrated in the west of Chongqing. Influencing detection results showed that the spatial heterogeneity of PM2.5 concentration in the Chengdu-Chongqing urban agglomeration was influenced by the combined effects of climate factors, topographic factors, vegetation cover, and anthropogenic factors. Furthermore, elevation, slope, and road network density were regarded as the dominant factors influencing the spatial heterogeneity of PM2.5 concentration in the study area. Topographic factors and climate factors showed the highest and lowest contribution rate to the spatial heterogeneity of PM2.5 concentration, respectively. The contribution rate of topographic factors and anthropogenic factors had gradually increased, and the contribution rate of climate factors and vegetation cover had gradually decreased in the study area from 2000 to 2021. Interaction detection results showed that the spatial heterogeneity of PM2.5 concentration in the Chengdu-Chongqing urban agglomeration was mostly affected by the interaction effects of elevation and road network density, slope, precipitation, sunshine duration, and land use type. The interaction detection results exhibited obvious regional differences on the city level. For instance, the spatial heterogeneity of PM2.5 concentration in Chengdu, Deyang, and Leshan was mostly affected by the interaction between different influencing types, and the spatial heterogeneity of PM2.5 concentration in Dazhou, Meishan, Ya'an, Ziyang, Neijiang, and Zigong was mostly affected by the interaction within a single influencing type.
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Studying the spatial-temporal variation in net primary productivity (NPP) in terrestrial vegetation ecosystems and its driving forces in southwest China is of great importance for regional eco-environmental protection. The spatial and temporal changes in net primary productivity (NPP) in terrestrial vegetation ecosystems and its responding characteristics to climate change and human activities were explored in this study on the basis of the Moderate Resolution Imaging Spectroradiometer (MODIS) NPP from 2000 to 2021, in situ meteorological data from 1999 to 2021, and land use type datasets from 2000 to 2020 using principal component analysis, residual analysis, Theil-Sen Median analysis, and partial correlation analysis. The results showed that on a temporal scale, the vegetation NPP showed a fluctuating upward trend, with a rate of 3.54 g·(m2·a)-1in southwest China from 2000 to 2021. Meanwhile, under the influence of climate change and human activities, NPP of farmland, grassland, and forests all showed an upward trend, but the magnitude of the increasing trends of farmland NPP was the most significant. On the spatial scale, the areas with an upward trend in vegetation NPP accounted for 89.06% in southwest China, and the areas with significant and extremely significant increases were mainly distributed in southern Guangxi, eastern Sichuan, western Chongqing, and the junction areas of Yunnan and Guizhou. Climate change and human activities had dual effects on vegetation growth in southwest China, and the proportions of the areas with upward trends in farmland NPP were higher than that of grassland and forests both under the influences of climate change and human activities. The correlations between vegetation NPP and climate factors showed obvious regional differences in southwest China. On the regional scale, the areas with a positive correlation between vegetation NPP and temperature, precipitation, and sunshine duration were greater than that of the areas with a negative correlation. However, an opposite relationship could be found between vegetation NPP and biological aridity/humidity index. Among them, the areas with a positive correlation between vegetation NPP and temperature were greater than that with other climate factors. In terms of different vegetation ecosystems, temperature, precipitation, and sunshine duration had a stronger role in promoting NPP variation in the grassland ecosystem than in farmland and forest ecosystems. The transformation of other land use types to forest land had contributed to vegetation improvement in southwest China.
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Ecossistema , Modelos Teóricos , Humanos , China , Florestas , Temperatura , Mudança ClimáticaRESUMO
This study explored the temporal and spatial variation in PM2.5 concentration and its relationship with the vegetation landscape pattern in three typical economic zones in China, which is of great significance for regional PM2.5pollution control and atmospheric environmental protection. In this study, the pixel binary model, Getis-Ord Gi* analysis, Theil-Sen Median analysis, Mann-Kendall significance test, Pearson correlation analysis, and multiple correlation analysis were used to explore the spatial cluster and spatio-temporal variation in PM2.5 and its correlation with the vegetation landscape index in the three economic zones of China on the basis of PM2.5 concentration data and MODIS NDVI data set. The results showed that PM2.5 in the Bohai Economic Rim was mainly dominated by the expansion of hot spots and the reduction in cold spots from 2000 to 2020. The proportion of cold spots and hot spots in the Yangtze River Delta showed insignificant changes. Both cold and hot spots in the Pearl River Delta had expanded. PM2.5 showed a downward trend in the three major economic zones from 2000 to 2020, and the magnitudes of increasing rates were higher in the Pearl River Delta, followed by those in the Yangtze River Delta and Bohai Economic Rim. From 2000 to 2020, PM2.5 exhibited a downward trend in the context of all vegetation coverage grades, and PM2.5 had most significantly improved within extremely low vegetation coverage in the three economic zones. On the landscape scale, PM2.5 values were mostly correlated with aggregation index in the Bohai Economic Rim, with the largest patch index in the Yangtze River Delta and Shannon's diversity in the Pearl River Delta, respectively. Under the context of different vegetation coverage levels, PM2.5showed the highest correlation with aggregation index in the Bohai Economic Rim, landscape shape index in the Yangtze River Delta, and percent of landscape in the Pearl River Delta, respectively. PM2.5 showed significant differences with vegetation landscape indices in the three economic zones. The combined effect of multiple vegetation landscape pattern indices on PM2.5 was stronger than that of the single vegetation landscape pattern index. The above results indicated that the spatial cluster of PM2.5 in the three major economic zones had changed, and PM2.5 showed a decreasing trend in the three economic zones during the study period. The relationship between PM2.5 and vegetation landscape indices exhibited obvious spatial heterogeneity in the three economic zones.
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Vegetation net primary productivity (NPP) is an important parameter for evaluating the quality of terrestrial ecosystems. It is of great importance to study the spatio-temporal evolution of vegetation NPP and its driving force for regional ecological environment protection and sustainable development. On the basis of MODIS NPP data, meteorological data, DEM data, population density data, GDP data, and land use type data, this study used linear regression analysis, R/S analysis, and a Geodetector model to analyze the spatio-temporal variation in vegetation NPP and its future changing trend on both regional and landform scales and to detect the influencing factors that affect the spatial differentiation of vegetation NPP. The results showed that the vegetation NPP exhibited an extremely significant upward trend in southwest China from 2000 to 2020. On the landform scale, the vegetation NPP had showed an upward trend in all landforms, except for the southern Tibet Plateau; among them, the vegetation NPP in the Sichuan Basin showed the most obvious upward trend. The variation in vegetation NPP exhibited obvious spatial heterogeneity in southwest China, with the changing rate of "high in the east and low in the west." The areas with an upward trend of vegetation NPP were greater than the areas with a downward trend, but the changing trend was dominated by a decreasing trend in the future, both in southwest China and each landform unit. The Geodetector results showed that elevation was the dominant factor controlling the spatial differentiation of vegetation NPP in southwest China and all landform units, except for the Yunan-Guizhou Plateau, in which the spatial differentiation of vegetation NPP was mostly dominated by temperature. The interaction detection results showed that the interaction between the influencing factors was manifested as two-factor enhancement or nonlinear enhancement. The interaction between elevation and temperature showed the highest impact on vegetation NPP distribution. On the landform scale, the spatial differential of vegetation NPP was dominated by the interaction between elevation and climate factors or elevation and GDP in the Guangxi Hills, Sichuan Basin, Zoige Plateau, Hengduan Mountains, and southern Tibet Plateau and between climate factors in the Yunan-Guizhou Plateau. The above results indicated that vegetation NPP variation and the influencing factors that dominate its spatial differential in southwest China showed obvious scale effects. Therefore, exploring the dynamic variation in vegetation NPP and its influencing factors at different spatial scales has practical significance for a comprehensive understanding of the vegetation cover situation and formulating regional ecological restoration plans in southwest China.
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Ecossistema , Modelos Teóricos , China , Mudança Climática , TibetRESUMO
D-Pantothenic acid (D-PA) is an essential vitamin with wide applications. However, the biotechnological production of D-PA is still not competitive with the chemical synthesis in terms of production cost. Ketopantoate hydroxymethyltransferase is a crucial enzyme in the D-PA synthetic pathway in Escherichia coli encoded by the panB gene. Here a hot spots study was applied to a ketopantoate hydroxymethyltransferase from Corynebacterium glutamicum (CgKPHMT) to relieve the product inhibitory effect and thus improve the D-PA production. Compared with the wild type, the double-site variant CgKPHMT-K25A/E189S showed 1.8 times higher enzyme activity and 2.1 times higher catalytic efficiency, 1.88 and 3.32 times higher inhibitory constant of α-ketoisovalerate and D-PA, respectively. The D-PA yield using E. coli W3110 adopted the double-site variant was 41.17 g·L-1 within 48 h, a 9.80 g·L-1 increase. Structural analysis of K25A/E189S revealed the expansion of the entry channel and the change of the electric charge from negative to uncharged due to the substitution from glutamic acid to serine at site 189. Our study emphasized the positive roles of ketopantoate hydroxymethyltransferase in D-PA production and paved the way by analyzing critical enzymes in the synthetic pathway of E. coli to increase the D-PA yield.
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Hidroximetil e Formil Transferases , Ácido Pantotênico , Ácido Pantotênico/química , Ácido Pantotênico/genética , Escherichia coli/metabolismo , Sequência de Bases , Hidroximetil e Formil Transferases/genética , Hidroximetil e Formil Transferases/metabolismo , Glicina Hidroximetiltransferase/genética , Glicina Hidroximetiltransferase/metabolismoRESUMO
Using the MOD13A3 NDVI time series from 2000 to 2020, climate date from 1999 to 2020, and land use type data in 2000 and 2020, the spatio-temporal variation in vegetation cover and the driving mechanisms of climate change and human activities to vegetation variation were analyzed based on Theil-Sen Median analysis, the Mann-Kendall significance test, the multi-collinearity test, residual analysis, and relative analysis. The results showed that the vegetation cover exhibited a fluctuating and increasing trend with a magnitude of 0.0016 a-1 in southwest China from 2000 to 2020. The increasing trend of vegetation cover was mostly significant in the Guangxi Hills and Yunnan-Guizhou Plateau and slightly significant in the Tibet Plateau. The vegetation cover had increased in the context of climate change and human activities, with an increasing rate of 0.0010 a-1 and 0.0006 a-1, respectively. The vegetation improvement was mostly dominated by the combination effects of climate change and human activities. The vegetation improvement was dominated by climate change, and the relative role of climate change reached 61.86%. What is more, the vegetation degradation was dominated by human activities, and the relative role of human activities reached 58.39%. Vegetation cover was positively related to minimum temperature, precipitation, maximum temperature, potential evapotranspiration rate, and relative humidity and negatively related to mean temperature, atmosphere pressure, sunshine duration, warmth index, and humidity index. As a whole, the minimum temperature, sunshine duration, and precipitation were the dominant climate factors affecting the vegetation variation in southwest China. Furthermore, the land use and land cover change were significantly related to vegetation variation in southwest China. The implementation of ecological afforestation projects could be beneficial to regional vegetation improvement, whereas the vegetation degradation was mostly conducted by the built-up land expansion.
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Condução de Veículo , Humanos , China , Tibet , Atividades Humanas , Mudança Climática , Temperatura , EcossistemaRESUMO
AIMS/INTRODUCTION: Emerging evidence has suggested the detrimental role of oxidative stress in aggravating ischemia and reperfusion (IR) injury in diabetic livers. Interplay between oxidative stress and mitophagy has been shown. However, the role and mechanism of mitophagy in regulating oxidative stress and IR injury in diabetic livers remain unclear. MATERIALS AND METHODS: Wild-type and db/db (DB) mice were subjected to a partial warm liver IR model. Liver injury, oxidative stress, mitophagy and related molecular pathways were analyzed. RESULTS: Here, we found that increased liver IR injury was observed in DB mice, as evidenced by higher levels of serum alanine aminotransferase and serum aspartate, worsened liver architecture damage and more hepatocellular death. DB mice also showed increased mitochondrial oxidative stress. Mitochondrial reactive oxygen species scavenge alleviated liver IR injury in DB mice. Mechanistic analysis showed that 5' adenosine monophosphate-activated protein kinase-mediated mitophagy was suppressed in DB mice post-IR. Pharmacological activation of 5' adenosine monophosphate-activated protein kinase by its agonist effectively restored mitophagy activation, leading to decreased mitochondrial oxidative stress and attenuated liver IR injury in DB mice. CONCLUSIONS: Our findings showed that diabetes increased oxidative stress to exacerbate liver IR injury by impairing 5' adenosine monophosphate-activated protein kinase-mediated mitophagy. Strategies targeting oxidative stress and mitophagy might provide a promising approach to ameliorate liver IR injury in diabetes patients.
Assuntos
Diabetes Mellitus Experimental , Hepatopatias , Traumatismo por Reperfusão , Camundongos , Animais , Mitofagia , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/metabolismo , Fígado/metabolismo , Estresse Oxidativo , Hepatopatias/etiologia , Isquemia/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismoRESUMO
The ion-enrichment inside carbon nanotubes (CNTs) offers the possibility of applications in water purification, ion batteries, memory devices, supercapacitors, field emission and functional hybrid nanostructures. However, the low filling capacity of CNTs in salt solutions due to end caps and blockages remains a barrier to the practical use of such applications. In this study, we fabricated ultra-short CNTs that were free from end caps and blockages using ball milling and acid pickling. We then compared their ion-enrichment capacity with that of long CNTs. The results showed that the ion-enrichment capacity of ultra-short CNTs was much higher than that of long CNTs. Furthermore, a broad range of ions could be enriched in the ultra-short CNTs including alkali-metal ions (e.g., K+), alkaline-earth-metal ions (e.g., Ca2+) and heavy-metal ions (e.g., Pb2+). The ultra-short CNTs were much more unobstructed than the raw long CNTs, which was due to the increased orifice number per unit mass of CNTs and the decreased difficulty in removing the blockages in the middle section inside the CNTs. Under the hydrated-cation-π interactions, the ultra-short CNTs with few end caps and blockages could highly efficiently enrich ions.
RESUMO
Structurally well-defined discrete d/f heterometallic complexes show diverse application potential in electrooptic and magnetic materials. However, precise control of the component and topology of such heterometallic compounds with fine-tuned photophysical properties is still challenging. Herein, we report the stereocontrolled syntheses of a series of LnIII-PtII heterometallic cages through coordination-driven self-assembly of enantiopure alkynylplatinum-based metalloligands (L1R/S, L2R/S) with lanthanide ions (Ln = EuIII, YbIII, NdIII, LuIII). Taking advantage of the metal-to-ligand charge transfer (MLCT) excited state on the designed alkynylplatinum ligands, the excitation window for the sensitized near-infrared (NIR) luminescence on the YbIII- and NdIII-containing cages can be extended to the visible region (up to 500 nm). Linear temperature-dependent red and NIR emissions observed on the Ln4(L2R/S)6 (LnIII = EuIII and YbIII, respectively) complexes suggest their potential applications as luminescent temperature sensors, with sensitivities of -0.54% (LnIII = EuIII, 77-250 K) and -0.17% (LnIII = YbIII, 77-300 K) per K achieved. This work not only offers a good strategy to prepare new d/f heterometallic supramolecular cages but also paves the way for the design of stimuli-responsive luminescent materials.