Nanopores have become one of the most important tools for single-molecule sensing, but the challenge for selective detection of specific biomolecules still exists. In this contribution, we develop a ...new technique for sensing carcinoembryonic antigen (CEA), one of the important cancer biomarkers, using solid-state nanopores as a tool. The method is based on the specific affinity between aptamer (Apt) modified magnetic Fe3O4–Au nanoparticles (MNPs) and CEA, and the formed CEA–Apt–MNPs and remaining Apt–MNPs can transport the nanopores by applying a positive potential after magnetic separation. Due to the obvious particle size difference between CEA–Apt–MNPs and Apt-MPs, their corresponding blockage signals could be distinguished completely by the degree of the current decline. Moreover, the frequency of the blockage signals for CEA–Apt–MNPs is proportional to the concentration of CEA within certain limits, indicating that our designed nanopore sensing strategy can quantitatively detect CEA in complex samples. This work demonstrates that our designed nanopore-based strategy can be used for CEA sensing with good selectivity and sensitivity and also can be used to analyze other protein biomarkers for early diagnosis and monitoring of cancer, though the detection limit (0.6 ng/mL) is not relatively low. In future works, we plan to improve our detection limit by the improvement of the nanopipette preparation technology and detection method.
Socioeconomic development has led to increased consumption of both blue and green water. Consequently, China is facing serious water scarcity issue. However, few studies have investigated ...interactions of blue and green water footprints, as well as driving forces underlying the changes in water footprints across provinces and sectors. To fill in this knowledge gap, we quantified the spatial-temporal dynamics of the blue and green water footprint (BWF and GWF, respectively), and analyzed the key factors that drive the provincial-level changes in BWF and GWF from 2002 to 2012. The analysis is facilitated by the approaches of multi-region input-output analysis and structural decomposition analysis, and we developed one decoupling index to quantify the water-economy relation and substitution between green and blue water. The results show that China's BWF averaged at 161 billion m3/yr, about one-third the size of the GWF. In addition, water scarce provinces in Northern China were moving towards decoupling between economic growth and blue water consumption, with GWF playing an increasingly important role. The changes in the WFs were mainly influenced by changes in affluence (final demand per capita), technological improvements (decreased direct water consumption intensity), and consumption pattern (composition of the final demand) rather than changes in the population and export. Technology improvement, consumption pattern shift and industrial structure adjustment contribute to WF reductions, thus help improve water security and sustainability in China. This study provides a new approach to analyze water-economy relations for water scarce countries.
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While mesoscale eddies can trap and transport chlorophyll (CHL) within the water columns, satellite measurements can only observe CHL at the sea surface. Here, we estimate the eddy-induced CHL ...distribution based on satellite observations, Argo float measurements, and global empirical models. The combination of satellite altimeter data and Argo measurements is used to detect eddy boundaries by tracking the outermost closed contours of potential vorticity (PV) at depth; then, sea surface CHL from satellite observations, together with their vertical distributions estimated from models are used to derive the CHL within eddy boundaries. We find that the CHL trapped by eddies can reach 3.2 × 1012g, which is about half of the total CHL in the ocean; the global time-mean CHL eddy-induced zonal transport adds up to 5.7 × 103 g/s westward. The results show that oceanic mesoscale eddies play an important role in the elevated CHL in the interior of the ocean.
•The CHL trapped by eddies is quantified based on observed data and the model.•The eddy-trapped CHL is found to be about half of the total CHL in the ocean.•Eddies elevate CHL in the interior of the ocean.
Graft copolymers consisting of two different zwitterionic blocks were synthesized via reversible addition fragmentation chain transfer polymerization. These polymers showed dual properties of thermo- ...and pH-responsiveness in an aqueous solution. Ultraviolet–visible spectroscopy and dynamic light scattering were employed to study the phase behavior under varying temperatures and pH values. Unlike the phase transition temperatures of other graft copolymers containing nonionic blocks, the phase transition temperature of these polymers was easily tuned by changing the polymer concentration. Owing to the biocompatible and stimuli-responsive nature of the polymers, this system was shown to effectively release proteins (lysozyme) while simultaneously protecting them against denaturation. The positively charged lysozyme was shown to bind with the negatively charged polymer at the physiological pH (pH 7.4). However, it was subsequently released at pH 3, at which the polymer exhibits a positive charge. Protein aggregation studies using a residual enzymatic activity assay, circular dichroism, and a Thioflavin T assay revealed that the secondary structure of the lysozyme was retained even after harsh thermal treatment. The addition of these polymers helped the lysozyme retain its enzymatic activity and suppressed its fibrillation. Both polymers showed excellent protein protection properties, with the negatively charged polymer exhibiting slightly superior protein protection properties to those of the neutral polymer. To the best of the authors’ knowledge, this is the first study to develop a graft copolymer system consisting of two different zwitterionic blocks that shows dual thermo- and pH-responsive properties. The presence of the polyampholyte structure enables these polymers to act as protein release agents, while simultaneously protecting the proteins from severe stress.
Undercooling of Cu-based alloys often induces metastable liquid phase separation followed by rapid solidification of separated liquids. The rapid solidification can help freeze in the morphology of a ...higher-melting liquid and eases difficulties in studies of liquid phase separation kinetics. In the present work, the influence of static magnetic fields on liquid phase separation in bulk Cu
Co
composition was investigated. Inductively melted samples were glass-fluxed, undercooled and solidified under uniform and non-uniform magnetic fields generated by a superconducting magnet. Solidification microstructure of the phase-separated samples was examined using an optical microscope. The imposition of the magnetic fields, both uniform and non-uniform, altered the morphology, segregation pattern and size distribution of Co-rich droplets due to liquid phase separation. The imposition of the non-uniform magnetic fields with positive and negative gradients brought about segregation of the Co-rich droplets at the top and the bottom side of the samples, respectively. Such influence of the static magnetic fields is interpreted by assuming intensification of convective flow and Kelvin force-controlled migration of the Co-rich droplets. This article is part of the theme issue 'Heterogeneous materials: metastable and non-ergodic internal structures'.
The outbreak of the 2019-nCoV infection began in December 2019 in Wuhan, Hubei province, and rapidly spread to many provinces in China as well as other countries. Here we report the epidemiological, ...clinical, laboratory, and radiological characteristics, as well as potential biomarkers for predicting disease severity in 2019-nCoV-infected patients in Shenzhen, China. All 12 cases of the 2019-nCoV-infected patients developed pneumonia and half of them developed acute respiratory distress syndrome (ARDS). The most common laboratory abnormalities were hypoalbuminemia, lymphopenia, decreased percentage of lymphocytes (LYM) and neutrophils (NEU), elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH), and decreased CD8 count. The viral load of 2019-nCoV detected from patient respiratory tracts was positively linked to lung disease severity. ALB, LYM, LYM (%), LDH, NEU (%), and CRP were highly correlated to the acute lung injury. Age, viral load, lung injury score, and blood biochemistry indexes, albumin (ALB), CRP, LDH, LYM (%), LYM, and NEU (%), may be predictors of disease severity. Moreover, the Angiotensin II level in the plasma sample from 2019-nCoV infected patients was markedly elevated and linearly associated to viral load and lung injury. Our results suggest a number of potential diagnosis biomarkers and angiotensin receptor blocker (ARB) drugs for potential repurposing treatment of 2019-nCoV infection.
Human cardiac organoids (hCOs), three-dimensional (3D) cellular constructs similar to in vivo organ, are new-generation models. To a large extent, a hCO retains the biological characteristics and ...functions of cells in vivo more accurately than previous models. With the continuous development of biotechnology, the hCO model is becoming increasingly complex and mature. High-fidelity hCOs help us better explore the mysteries of human physiology and integrate phenotypes with living functions into models. Here, we discuss recent advances in the methods of constructing human cardiac organoids and introduce applications of hCOs, especially in modeling cardiovascular diseases, including myocardial infarction, heart failure, genetic cardiac diseases, and arrhythmia. In addition, we propose the prospects for and the limitations of hCOs. In conclusion, a greater understanding of hCOs will provide ways to improve hCO construction and make these models useful for future preclinical studies.
Chronic stress is known to promote inflammatory bowel disease (IBD), but the underlying mechanism remains largely unresolved. Here, we found chronic stress to sensitize mice to dextran sulfate sodium ...(DSS)-induced colitis; to increase the infiltration of B cells, neutrophils, and proinflammatory ly6Chi macrophages in colonic lamina propria; and to present with decreased thymus and mesenteric lymph node (MLN) coefficients. Circulating total white blood cells were significantly increased after stress, and the proportion of MLN-associated immune cells were largely changed. Results showed a marked activation of IL-6/STAT3 signaling by stress. The detrimental action of stress was not terminated in IL-6−/− mice. Interestingly, the composition of gut microbiota was dramatically changed after stress, with expansion of inflammation-promoting bacteria. Furthermore, results showed stress-induced deficient expression of mucin-2 and lysozyme, which may contribute to the disorder of gut microbiota. Of note is that, in the case of cohousing, the stress-induced immune reaction and decreased body weight were abrogated, and transferred gut microbiota from stressed mice to control mice was sufficient to facilitate DSS-induced colitis. The important role of gut microbiota was further reinforced by broad-spectrum antibiotic treatment. Taken together, our results reveal that chronic stress disturbs gut microbiota, triggering immune system response and facilitating DSS-induced colitis.
The escalating issue of soil saline-alkalization poses a growing global challenge. Leymus chinensis is a perennial grass species commonly used in the establishment and renewal of artificial ...grasslands that is relatively tolerant of saline, alkaline, and drought conditions. Nonetheless, reduced seed setting rates limit its propagation, especially on alkali-degraded grassland. Inter-annual variations have an important effect on seed yield and germination under abiotic stress, and we therefore examined the effect of planting year on seed yield components of L. chinensis.
We grew transplanted L. chinensis seedlings in pots for two (Y
), three (Y
), or four (Y
) years and collected spikes for measurement of seed yield components, including spike length, seed setting rate, grain number per spike, and thousand seed weight. We then collected seeds produced by plants from different planting years and subjected them to alkaline stress (25 mM Na
CO
) for measurement of germination percentage and seedling growth.
The seed setting rate of L. chinensis decreased with an increasing number of years in pot cultivation, but seed weight increased. Y
plants had a higher seed setting rate and more grains per spike, whereas Y
plants had a higher thousand seed weight. The effects of alkaline stress (25 mM Na
CO
) on seed germination were less pronounced for the heavier seeds produced by Y
plants. Na
CO
caused a 9.2% reduction in shoot length for seedlings derived from Y
seeds but a 22.3% increase in shoot length for seedlings derived from Y
seeds.
Our findings demonstrate significant differences in seed yield components among three planting years of L. chinensis under pot cultivation in a finite space. Inter-annual variation in seed set may provide advantages to plants. Increased alkalinity tolerance of seed germination was observed for seeds produced in successive planting years.
Control of phosphate in natural waters is very important to prevent eutrophication. In this study, a novel zirconium/PVA modified adsorptive flat-sheet PVDF membrane was applied for phosphate removal ...from simulated contaminated water. The uptake of phosphate decreased with an increase in solution pH; the best performance was observed at pH 2.0. Most of ultimate uptake occurred in 10 h, and the adsorption equilibrium was established in 30 h for both pH 2.0 and pH 7.0. The Langmuir adsorption isotherm better represented the experimental observation than the Freundlich adsorption isotherm; the maximum adsorption capacity of 73.99 and 21.64 mg P/g was achieved at pH 2.0 and pH 7.0, respectively. The adsorption occurred rapidly in the first 10 h, leading to 90% of the ultimate removal. The uptake of phosphate was inhibited by the commonly existing anions with a sequence of CO3 2– < SiO3 2– < humic acid < F– < Cl– < SO4 2–. The membrane with an area of 12.56 cm2 could treat 4.63 and 1.82 L phosphate solution through a filtration mode with an influent phosphorus concentration of 216 μg/L and pH 2.0 and pH 7.0, respectively, to meet the USEPA requirement for a reservoir of 25 μg/L. The membrane demonstrated a good regeneration–reuse capacity through a series of regeneration–reuse studies. It was found that the uptake was mainly due to an ion exchange process between chloride and phosphate ions.
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