Low O2 Concentrations Research Articles

Influences of Urban Discharges and Urban Heat Effects on Stream Temperature

Urban areas with dark and impermeable surfaces are known to have a heating effect on air and still water compared to surrounding areas, called the urban heat island effect (UHI). UHI and stormwater discharges’ collective impact on stream temperature, especially regarding seasonal changes, is a less-studied field. In this study, the temperature effect of the urban village Aarslev on Stream Vindinge in Southern Denmark was examined. Loggers (ID A–L) were placed in Stream Vindinge in 2020–2021, measuring temperature (°C) and pressure (kPa). Outlets were analyzed with respect to origin: Direct stormwater outlets (rain ÷ basin), stormwater delayed by ponds (rain + basin), common overflow, and common sewage from WWTP. Data showed the stream temperature rise through Aarslev village in all months (except March) with 0.3–1.9 °C, most notably in the summer months. A one-way ANOVA confirmed that the upstream station A and downstream station K were significantly different (p-values < 0.001). No significant difference in temperatures between the different outlet types was found. An increase in stream temperature was observed in response to rain events, followed by a temperature decrease. This was assumed to be a “first heat flush”. This was speculated to mean less optimal conditions for trout and sensitive macroinvertebrates not because of heat shock, but rather to lower O2 concentrations and higher mineralization. River and lake temperatures are projected to increase, and this effect might become more pronounced. A decrease in stream temperature was observed after the village (station L). Therefore, it was concluded that the rise in temperature through the village was due to UHI.

Meso-scale simulation of Li–O2 battery discharge process by an improved lattice Boltzmann method

The discharge process of lithium–oxygen battery (LOB) is a highly complicated multi-physics coupling phenomenon. Moreover, the cathode morphology presents a complex multi-scale structure with pore size ranging from nanometers to micronmeters, and plays a crucial role in determining the discharge performance. In this work, the cathodes consisting of carbon paper, electrode material, and electrolyte are first numerically reconstructed using a two-step reconstruction method considering the multi-scale morphology. A lattice Boltzmann model with an improved partial bounce-back scheme is proposed for modeling the discharge process given that the electrode porosity changes with the progress of discharge. The effects of micron-scale electrode spatial distribution on the O2 diffusion and LOB discharge performance are investigated. Results show that the increment of the electrode dispersion degree increases the O2 diffusion resistance due to the increase of electrolyte-electrode specific interface area. A large local electrode load near O2 inlet leads to a high O2 diffusion resistance and low O2 concentration owing to the large specific interface area and electrode volume. Cathodes with the minimum electrode load and maximum electrode dispersion degree present the optimal specific capacity of LOB. However, the specific capacity first increases significantly and then slightly decreases with the increase of local electrode load.

Gas Absorbent Based Modified Atmosphere Packaging to Optimize Dragon Fruit Shelf Life

Dragon fruit is a promising export commodity for Indonesia. But its short shelf-life is a big challenge for an international shipping by sea. This study aims to prolong the dragon fruit shelf life by implementing gas absorbent based Modified Atmosphere Packaging (MAP) in combination with cold storage. This technique decreases the fruit physiological processes by lowering O2 concentration (%) inside the MAP. The selected dragon fruit was packed with gas absorbent-based MAP with different O2 absorber capacities (30 cc; 60 cc; and 120 cc) and plastic types (biodegradable plastic and LDPE). Each treatment was also varied with the use of H2O absorbent and perforation. Then, the dragon fruit in MAP was stored at 5°C and 90% RH for 6 weeks as shipping simulation. After storage, the dragon fruit was transferred to 27°C room temperature without MAP. The results showed that the application of gas absorbent-based MAP, additional treatments, and low temperature were generally able to maintain the quality of dragon fruit up to 6 weeks in cold storage. However, dragon fruit developed signs of chilling injury, increased water loss, increased weight loss, decreased hardness, skin damage, fin withering, and mold growth after transfer at 27°C room temperature without MAP.

고 CO2농도 기체조성으로 자동제어된 용기에 저장된 삼겹살의 품질특성

Container system automatically controlled in its atmosphere of high CO2/low O2 was devised to contain and store pork belly meat at chilled temperature. The meat in the container system was compared in the quality preservation at 0°C for 21 days to that in air-filled container and vacuum package. The container atmosphere could be controlled to be of 47~60% CO2 and 7~10% O2 through time-controlled intermittent CO2 injection. The controlled atmosphere in the developed system was effective in suppressing pH change and aerobic bacterial growth contributing to sensory quality preservation. Compared to control of air-filled container, vacuum packaging showed lower microbial growth and slower pH change on the meat but with high drip loss. The devised container system to keep high CO2 and mildly low O2 concentrations is effective in the meat quality preservation on overall, and may be extended to a variety of meat products with possible modification tuned for product requirements.

Calcium chloride and chitosan coatings combined with modified atmosphere packaging extend the shelf life and maintain the quality of frozen mango slices

SummaryThe combination of modified atmosphere packaging (MAP) and coating effectively improved the gas environment in packaging trays with low O2 concentrations (1.46–4.24%). This led to a significantly higher quality in terms of delaying the colour change, preserving phytochemical and antioxidant concentrations when mangoes were coated with 0.5% CaCl2 (CA) or CA followed by 0.5% combined solution of CA plus chitosan (CA + Mix) and reducing weight loss with the CA + Mix coating. There were no significant differences in the sensory scores between fresh and frozen–thawed ripe mango regarding overall acceptability, appearance, colour, flavour and texture. These findings suggested that the shelf life of frozen mango could be extended by 6 months with high quality with the combination of MAP and coating with CA + Mix or CA. This approach has the potential to increase the value chain of ripe mango through commercial cost savings.

Existence of circadian rhythm and its response behavior under different storage conditions of soybean sprouts

The circadian system plays an essential role in plant cells, and numerous physiological events are generally modulated by circadian clock genes. To further improve postharvest handling of fresh produce, it is vital to understanding the behavior of clock gene expression and its underlying interactions with changes in quality. In this study, the effect of temperature and controlled atmosphere storage on the expression of clock genes (GmLCL1, GmPRR7, GmGI, GmTOC1, and GmLUX), postharvest quality characteristics and their related genes in soybean sprouts were investigated. By fitting the obtained gene expression level using the qPCR method with the cosine curve equation, it was successfully found that the circadian rhythm existed under constant dark storage conditions of soybean sprouts. A significant rhythm in clock gene expression was observed in control soybean sprouts. In contrast, low temperature storage diminished the cyclic expression of GmLCL1, GmPRR7, and GmTOC1, which also affected GmGI and GmLUX expression. Additionally, high CO2 concentrations during storage disturbed the circadian clock by affecting the phase and amplitude of each gene; for low O2 concentrations, it was only affected by amplitude. Interestingly, low temperature, low O2, and high CO2 maintained postharvest quality, including reduced respiration, weight loss and browning incidence. The expression behaviors of postharvest quality attribute-related genes (GmFUM1, GmCS, Gm2-OGDH, GmPPO1, GmPAL) were also influenced by the storage treatments. Overall, the findings first suggest a possible link between clock disruption and postharvest quality maintenance of soybean sprouts.

Effects of oxygen concentration on devolatilization and combustion behavior of coal particles: A multi-parameter study

The devolatilization and volatile combustion of lignite coal (LC), sub-bituminous coal (SBC) and bituminous coal (BC) with different O2 concentrations (21%-50%) were investigated on a concentrating photothermal experiment platform. The characteristics and mechanism of different coal particle combustion were analyzed by using multiple diagnostics, including Planar Laser Induced Fluorescence (PLIF) of OH radicals and polycyclic aromatic hydrocarbons (PAHs), high-speed cinematography and FT-IR. The results showed that, with increasing O2 concentration, the ignition delay time (tign) of different ranks of coal decreased, which was associated with the increase of OH concentrations during the ignition stage. The good correlation between tign and OH concentration was observed. For the volatile combustion, the OH concentration, volatile release amount and volatile flame duration time (tvol) significantly increased with the increasing of O2 concentration at low O2 concentrations. In the higher O2 concentrations, coals with different PAHs generation amount responded differently on the increasing of O2 concentration. On one hand, for the coals with lower PAHs generation amount, the OH concentration increased with the increasing of O2 concentration, while the tvol was not sensitive to changes of the O2 concentration. On the other hand, for the coals with higher PAHs generation amount, the OH concentration decreased with the increasing of O2 concentration while the tvol increased with the increasing of O2 concentration. It can be concluded that PAHs inhibited the OH generation, and the generation characteristics of OH and PAHs affected the sustained state of volatile combustion. The higher PAHs concentration consumed higher amount of OH during the volatile combustion. Meanwhile, with the increasing of PAHs concentration, the reaction rate of H + O2+M→HO2+M in which PAHs participate was increased, inhibiting the reaction H + O2→OH+O, and the increasing of polymer soot of PAHs will reduce the flame temperature through thermal radiation, which further inhibited the OH formation.

Tracking combustion behavior of copper monosulfide, ferrous sulfide, and chalcopyrite tablets by high-speed microscopic videography

A new suspended-combustion-test method involving high-speed digital microscopy and thermal measurements was developed to analyze small tablets of CuS, FeS, and CuFeS2 to elucidate their combustion behavior and phase changes in flash smelting. Moreover, the frequency of splash generation and homogeneous oxidation of the released gaseous sulfur from each sulfide were monitored. Microstructural analysis of quenched samples by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy revealed that the combustion intensity could be related to the formation of an oxide layer, which blocked the O2 supply to the sample interior. Moreover, the gas formed at various oxygen concentrations agitated the samples. In particular, the generated solid-oxide shell could move, the sulfide was exposed to the surface again, and the combustion reaction proceeded further. Insufficient agitation at lower O2 concentrations resulted in a thick and dense oxide layer, which blocked the O2 supply and caused extinction.

Experimental and kinetic study on the catalytic effect of AAEMs on coal char combustion under O2/CO2 atmospheres

The oxy-fuel combustion technology has attracted widespread attention because of its relatively low-cost and large-scale CO2 capture. During the oxy-fuel combustion process, the low diffusivity of O2 in CO2 brings several difficulties on coal char combustion due to N2 replacement with CO2. Catalytic combustion by adding alkali and alkaline earth metals (AAEMs) is an effective way to improve the coal char combustion performance. In this work, the catalytic effects of AAEMs on coal char combustion characteristics under different conditions were studied. Besides, the kinetic parameters of char combustion were obtained by Kissinger-Akahira-Sunose, Starink, and Flynn-Wall-Ozawa methods. Results showed that compared with other AAEMs (Na, Ca, and Mg), K showed better catalytic effects on ignition, burnout, and comprehensive combustion characteristics of coal char. The promotion effect of K on the combustion performance was gradually saturated when addition ratios exceeded 1 wt%. At low O2 concentrations or heating rates, K exhibited a strong catalytic effect on coal char combustion. Besides, K could accelerate the decrease in activation energy (Ea) of coal char combustion as char conversion (α) increased. When α was 0.9, the reduced effect of K on the Ea value was 13%. These results are expected to provide new insights into the improvement of coal char oxy-fuel combustion catalyzed by AAEMs.

A Numerical Study on Heat and Mass Transfer Coupled with Respiration Reaction within Stacked Spherical Postharvest Produce: Spatial Distribution and Temporal Variation

Reaction rate of respiration in postharvest horticultural produce is dependent on coupling effects of heat and mass transfer. The present work is aimed to develop a numerical model of heat and mass transfer coupled with respiration reaction for forced-air cooling (FAC) and modified atmosphere (MA) storage of postharvest produce. Wind tunnel model with a single bin of stacked spherical produce therein is used as a benchmark case to analyze spatial distribution and temporal variation of heat and mass transfer characteristics. Competitive diffusion of O2 results in the highest O2 partial pressure around 8 kPa between produce surface and core at 10 min during FAC combined with MA. With positions of such peaks moving inward, similar O2 partial pressure around 4 kPa is obtained in the vicinity of produce core at 30 min. This indicates comparative effects of convective removing and reaction consumption of O2. During the same process, under simultaneous effects of low temperature and O2 content, peak values of respiration heat between produce surface and core are generally below 60 W/m3 at 10 min, while two peaks in each produce individual basically merge together with reduced values to around 40 W/m3 at 20 min.

Laser-induced plasma-ignited hydrogen jet combustion in engine-relevant conditions

This work aims to investigate the mechanisms governing H2 jet flame evolution and stabilisation by precisely controlling the jet ignition location using a laser-induced plasma in compression-ignition engine-relevant conditions. The experiments examine the flame evolution with high-speed schlieren imaging and pressure trace measurements in an optically-accessible constant-volume combustion chamber over a range of ambient O2 concentration (10–21 vol%) and temperature (600–800 K) conditions. Optical results reveal that in most cases, a localised flame kernel forms at the time and location of the laser-induced plasma and grows in connected regions to engulf the entire upstream and downstream jet volume of the ignition spot. The images also reveal that the flame lift-off is sensitive to ambient O2 and temperature changes. The flame appears attached to the nozzle at 21 vol% O2, but becomes lifted at a lower ambient O2 concentration and a colder temperature. A simplified numerical analysis suggests that edge-flame deflagration into stratified premixed fuel-ambient reactant streams explains the lift-off response to ambient O2 and temperature changes. Furthermore, at the lowest tested O2 concentration, the flame stabilisation occurs in leaner mixtures at the jet peripheral where it is likely exposed to stronger turbulence-chemistry interactions.

Effects of Oxygen Content during Heat Treatment on Properties of Solution-Processed Cu2O-αFe2O3 Composite for Supercapacitor Application

The Cu2O-αFe2O3 composite film was heated in air (FC-A), O2 (FC-O) and vacuum (FC-V) respectively to investigate the effects of heat-treated conditions on the material and electrochemical characteristics. As a result, the heat treatment did not significantly affect the morphology but the grain size and crystal phase of the materials. In accordance with the oxygen content in the heat treatment environment, the heat-treated composite films performed as a mixed phase containing mainly CuFe2O4, parts of αFe2O3 (relatively high O2 content) and Cu-Sn alloy (low O2 content). With tuning the oxygen content in/on the crystal lattice of CuFe2O4 and αFe2O3, the energy storage mechanism of the composite electrode could be modified from the comprehensively capacitive and pseudocapacitive effects to an independent EDLC behavior. Compared with the FC-O and FC-V electrodes, the FC-A electrode presented a better capacitance retention (1.8% capacitance loss up to 2,000 cycles) and the highest specific capacitance (176.2 F·g−1 at 0.5 mA·cm−2). The outstanding performance can be ascribed to its lower charge transfer resistance, the porous feature having faster ion transportation efficiency and the additional pseudocapacitance provided by the Faradaic redox reaction.

Preservation Factors during Cretaceous Oceanic Anoxic Events in the Espírito Santo Basin, Southeast Brazil

The oceanic anoxic events (OAEs) are characterized by enhanced accumulation of organic matter in marine sediments. However, there is still an ongoing debate regarding the interplay between production and preservation during these events. Moreover, few studies provide quantitative estimations of primary productivity and/or the amount of carbon preserved during the OAEs. Here, we used geochemical data from multiple wells located at the Espírito Santo Basin that cover the intervals of events OAE1d and OAE2 to provide quantitative estimates of preservation factors. Our results show enhanced preservation during OAEs compared to modern conditions and a stronger preservation during OAE1d compared to OAE2 in the Espírito Santo Basin. The amount of preserved carbon could reach up to 8.6% during OAE1d, depending on the productivity of the system. In addition, we show that such improvement in preservation is linked to the bottom water with low-O2 concentrations and not due to fast burial caused by high sedimentation rates. Our findings are extremally relevant for organic carbon and source rock modelling studies since model simulations need quantitative estimations.

Role of carbide slag addition on NO emission characteristics during coal combustion

This work presents an experimental study on the NO emission characteristics of coal combustion with carbide slag addition. Combustion experiments were carried out in a fixed-bed reactor to investigate the effects of Ca/S molar ratio, oxygen concentration and reaction temperature on the transformation of fuel nitrogen to NO emission. Further, a pilot test was performed in a 30 kW CFB reactor to study the influence of carbide slag on the NO emission. Experimental results show that using carbide slag and a high Ca/S molar ratio promoted the fuel-N/NO conversion rate. The main contribution to the fuel-N/NO conversion rate increment was the catalytic role of carbide slag in the char-N/NO conversion process. The promotion effect of carbide slag on fuel-N/NO conversion was weakened at a higher temperature and lower O2 concentration. The pilot test results verified that using carbide slag promoted NO emission. Based on the test results, the fuel-N conversion route and the NO formation process during coal combustion with carbide slag addition were presented.

Influence of the parallel oil‐secondary air and F‐layer secondary air distribution on the flow, combustion, and NOx generation characteristics of FW down‐fired boilers retrofitted with a stable combustion technology

AbstractTo further reduce the NOx emissions of the down‐fired boiler while improving its low‐load stable combustion capacity, a new low NOx combustion organization mode that utilizes the high velocity parallel oil‐secondary air to improve the pulverized coal combustion process was proposed based on a novel stable combustion technology. We carried out cold airflow experiments under different oil‐secondary air and F‐layer secondary air distributions (mass flow rate ratios of 1:9, 1:3, 2:3) based on a 300 MWe Foster Wheeler down‐fired boiler to study its influence on the flow and mixing characteristics of the coal/airflow. Results show that the mixing between the oil‐secondary air and the fuel‐rich coal/airflow is gradually delayed with the increase of the secondary air distribution. When the secondary air distribution reaches more than 2:3, the oil‐secondary air starts to become the dominant airflow that influences the whole flow field in the furnace. Based on the result of the cold airflow experiment, we carried out industrial measurements under different parallel oil‐secondary air and F‐layer secondary air distributions (4:6, 5:5, 6:4) on a 600 MWe FW down‐fired boiler under the condition of using the high velocity oil‐secondary air. The ignition distance of the fuel‐rich coal/airflow, the flue gas temperature, the O2, CO, and NOx concentrations in the furnace were measured. At the secondary air distribution of 4:6, the ignition distance of the fuel‐rich coal/airflow was about 1.31 m. When the secondary air distribution was increased to 5:5 and 6:4, the ignition was put off, but the pulverized coal/airflow could still catch on fire in time. With the increase of the parallel oil‐secondary air proportion, the flame center in the furnace did not move downward substantially. In three cases, the lowest O2 concentrations in the inspection port area under the burner were all below 1% (peak CO concentration values were all above 28,000 ppm). The pulverized coal all burned in a strong reducing atmosphere. At secondary air distributions of 4:6, 5:5, and 6:4, NOx emissions of the boiler were, respectively, 825.83, 819.48, and 853.86 mg/Nm3 (O2 = 6%). The thermal efficiency was, respectively, 90.09%, 89.16%, and 90.98%. In actual operation, the recommended secondary air distribution is 6:4.

Ciliary flows in corals ventilate target areas of high photosynthetic oxygen production

Most tropical corals live in symbiosis with Symbiodiniaceae algae whose photosynthetic production of oxygen (O2) may lead to excess O2 in the diffusive boundary layer (DBL) above the coral surface. When flow is low, cilia-induced mixing of the coral DBL is vital to remove excess O2 and prevent oxidative stress that may lead to coral bleaching and mortality. Here, we combined particle image velocimetry using O2-sensitive nanoparticles (sensPIV) with chlorophyll (Chla)-sensitive hyperspectral imaging to visualize the microscale distribution and dynamics of ciliary flows and O2 in the coral DBL in relation to the distribution of Symbiodiniaceae Chla in the tissue of the reef building coral, Porites lutea. Curiously, we found an inverse relation between O2 in the DBL and Chla in the underlying tissue, with patches of high O2 in the DBL above low Chla in the underlying tissue surrounding the polyp mouth areas and pockets of low O2 concentrations in the DBL above high Chla in the coenosarc tissue connecting neighboring polyps. The spatial segregation of Chla and O2 is related to ciliary-induced flows, causing a lateral redistribution of O2 in the DBL. In a 2D transport-reaction model of the coral DBL, we show that the enhanced O2 transport allocates parts of the O2 surplus to areas containing less chla, which minimizes oxidative stress. Cilary flows thus confer a spatially complex mass transfer in the coral DBL, which may play an important role in mitigating oxidative stress and bleaching in corals.

Role of hypoxia preconditioning in therapeutic potential of mesenchymal stem-cell-derived extracellular vesicles.

The use of mesenchymal stem-cells (MSC) in cell therapy has received considerable attention because of their properties. These properties include high expansion and differentiation in vitro, low immunogenicity, and modulation of biological processes, such as inflammation, angiogenesis and hematopoiesis. Curiously, the regenerative effect of MSC is partly due to their paracrine activity. This has prompted numerous studies, to investigate the therapeutic potential of their secretome in general, and specifically their extracellular vesicles (EV). The latter contain proteins, lipids, nucleic acids, and other metabolites, which can cause physiological changes when released into recipient cells. Interestingly, contents of EV can be modulated by preconditioning MSC under different culture conditions. Among them, exposure to hypoxia stands out; these cells respond by activating hypoxia-inducible factor (HIF) at low O2 concentrations. HIF has direct and indirect pleiotropic effects, modulating expression of hundreds of genes involved in processes such as inflammation, migration, proliferation, differentiation, angiogenesis, metabolism, and cell apoptosis. Expression of these genes is reflected in the contents of secreted EV. Interestingly, numerous studies show that MSC-derived EV conditioned under hypoxia have a higher regenerative capacity than those obtained under normoxia. In this review, we show the implications of hypoxia responses in relation to tissue regeneration. In addition, hypoxia preconditioning of MSC is being evaluated as a very attractive strategy for isolation of EV, with a high potential for clinical use in regenerative medicine that can be applied to different pathologies.

Li-CO2/O2 battery operating at ultra-low overpotential and low O2 content on Pt/CNT catalyst

Li-CO2/O2 battery presents a promising solution to combine CO2 utilization and electrochemical energy storage. Herein, Pt nanoparticles (NPs) of 2.5 nm in mean size loaded uniformly on carbon nanotubes (Pt/CNT) were synthesized and served as cathodic catalysts. The Li-CO2/O2 battery with Pt/CNT catalyst were investigated in mixture gas of CO2 and O2 with O2 content varying from 0% to 20%. It has revealed that the Li-CO2/O2 (2% O2) battery, i.e., operating with 2% O2 content, displays a minimum overpotential of 0.31 V and a cycling stability of 127 cycles, which are significantly superior to the Li-CO2/O2 (20% O2) battery (0.51 V, 90 cycles) and the Li-CO2 battery (0% O2 content) (0.44 V, 110 cycles). Results of in-situ Fourier transform infrared (FTIR) spectroscopy have demonstrated the complete decomposition of Li2CO3 at 3.2 V in the Li-CO2/O2 (2% O2) battery. However, density function theory (DFT) calculations indicate that the decomposition energy barrier of Li2CO3 in Li-CO2/O2 (2% O2) battery is higher than that in Li-CO2 battery. SEM characterizations revealed a localized growth mechanism when O2 content is between 2% and 6% during the initial cycling, in which the Li2CO3 tends to form inside the Pt/CNT catalyst layer, rather than it distributes uniformly on both sides of the Pt/CNT catalyst layer with 0% or 20% O2 content. Such a growth mechanism ensures a better contacting interface between the Pt/CNT catalyst and Li2CO3, which plays a key role in optimal battery performance.

Primary Human Trophoblasts Mimic the Preeclampsia Phenotype after Acute Hypoxia-Reoxygenation Insult.

Preeclampsia (PE) is a pregnancy-specific disorder that affects 3 to 5% of pregnancies worldwide and is one of the leading causes of maternal and fetal morbidity and mortality. Nevertheless, how these events occur remains unclear. We hypothesized that the induction of hypoxic conditions in vitro in primary human trophoblast cells would mimic several characteristics of PE found in vivo. We applied and characterized a model of primary cytotrophoblasts isolated from healthy pregnancies that were placed under different oxygen concentrations: ambient O2 (5% pCO2, 21%pO2, 24 h, termed “normoxia”), low O2 concentration (5% pCO2, 1.5% pO2, 24 h, termed “hypoxia”), or “hypoxia/reoxygenation” (H/R: 6 h intervals of normoxia and hypoxia for 24 h). Various established preeclamptic markers were assessed in this cell model and compared to placental tissues obtained from PE pregnancies. Seventeen PE markers were analyzed by qPCR, and the protein secretion of soluble fms-like tyrosine kinase 1 (sFlT-1) and the placenta growth factor (PlGF) was determined by ELISA. Thirteen of seventeen genes associated with angiogenesis, the renin–angiotensin system, oxidative stress, endoplasmic reticulum stress, and the inflammasome complex were susceptible to H/R and hypoxia, mimicking the expression pattern of PE tissue. In cell culture supernatants, the secretion of sFlT-1 was increased in hypoxia, while PlGF release was significantly reduced in H/R and hypoxia. In the supernatants of our cell models, the sFlT-1/PlGF ratio in hypoxia and H/R was higher than 38, which is a strong indicator for PE in clinical practice. These results suggest that our cellular models reflect important pathological processes occurring in PE and are therefore suitable as PE in vitro models.

Preparation of AIE Functional Single-Chain Polymer Nanoparticles and Their Application in H2 O2 Detection through Intermolecular Heavy-Atom Effect.

Single-chain polymer nanoparticles (SCNPs) are soft matter constructed by intrachain crosslinks, with promising prospects in detection and catalysis. Herein, a fluorescent core (SCNPs) with aggregation-induced emission (AIE) is prepared, applying for H2 O2 detection through intermolecular heavy-atom effect. In detail, the SCNPs precursors are synthesized by ring-opening copolymerization. Then the SCNPs are prepared by intramolecularly cross-linking via olefin metathesis. Imitating the structure of AIE dots, SCNPs are encapsulated by H2 O2 -responsive polymers. Probably due to the stable secondary structure of SCNPs, the obtained micelles show stable fluorescence performance. Furthermore, as the heavy-atom, tellurium is introduced into the carriers to construct the heavy-atom effect. In this micelle-based system, the SCNPs act as the fluorescent core, and the stimuli-responsive polymer acts as the carrier and the fluorescent switch. The hydrophilicity of the tellurium-containing segment is affected by the concentration of H2 O2 , resulting in a change in the distance from the SCNPs, which ultimately leads to a change in the fluorescence intensity. Furthermore, tellurium is particularly sensitive to H2 O2 , which can detect low concentrations of H2 O2 . The SCNPs are merged with AIE materials, with the hope of exploring new probe designs.