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• A time-domain FEM-BEM iterative coupling algorithm with dual-independent discretizations in both time and space domains is proposed. • The force and displacement converting matrices and the time inter/extra-polation scheme are derived. • The advantages of TD-BEM are preserved in the coupling algorithm, with limited discretization and good efficiency. • The flexibilities and the versatilities for the coupling algorithm are released. A time-domain (TD) FEM-BEM iterative coupling algorithm with dual-independent discretizations in both time and space domains for dynamics is presented, allowing the independent temporal and spatial discretizations and solutions for each sub-domain in the coupled model. According to the continuity and equilibrium equations between the sub-domains of TD-FEM and TD-BEM, as well as the continuity condition along time, the displacement and force converting matrices and the time inter/extra-polation scheme in time domain are derived to exchange data between TD-FEM and TD-BEM nodes on the interface, which are not required to be positionally matched. The proposed iterative coupling algorithm with dual-independent discretizations in time and space domains is verified by two examples to be of the advantages of the independence for one's own formulation, high computational accuracy, good flexibility and versatility. [ABSTRACT FROM AUTHOR]

Background:: Despite the progress in perinatal-neonatal medicine, complications of extremely preterm infants continue to constitute the major adverse outcomes in neonatal intensive care unit. Human umbilical cord Wharton’s Jelly-derived mesenchymal stem cells (HUMSCs) may offer new hope for the treatment of intractable neonatal disorders. This study will explore the functional differences of HUMSCs between extremely preterm and term infants. Methods:: UMSCs from 5 extremely preterm infants(weeks of gestation: 22+5w,24+4w,25+3w,26 w,28 w) and 2 term infants(39 w,39+2w) were isolated, and mesenchymal markers, pluripotent genes, proliferation rate were analyzed. HUVECs were injured by treated with LPS and repaired by co-cultured with HUMSCs of different gestational ages. Results:: All HUMSCs showed fibroblast-like adherence to plastic and positively expressed surface marker of CD105,CD73 and CD90, but did not expressed CD45,CD34,CD14,CD79a and HLA-DR; HUMSCs in extremely preterm exhibited significant increase in proliferation as evidenced by CCK8, pluripotency markers OCT-4 tested by RT-PCR also showed increase. Above all, in LPS induced co-cultured inflame systerm, HUMSCs in extremely preterm were more capable to promote wound healing and tube formation in HUVEC cultures, they promoted TGFβ1 expression and inhibited IL6 expression. Conclusions:: Our results suggest that HUMSCs from extremely preterm infants may be more suitable as candidates in cell therapy for the preterm infants.

Orthobiologic procedures are based on altering the microenvironment of musculoskeletal tissues to induce an anti-inflammatory effect and reduce pain, promote healing of these tissues, or provide mechanical support. Allograft tissues have these inherent qualities and can be used as such. This could provide patients whose own autologous tissues may be compromised or have contraindications to harvesting an alternative to treat their orthopedic conditions. Although these allograft therapies are promising, they lack high-quality clinical studies and regulatory guidelines currently limit their use.

Polyoxymethylene dimethyl ethers (CH3-O-(CH2O)n-CH3, PODEn, n > 1) can be added to diesel to reduce air pollution caused by incomplete combustion. Driven by this need, a cost-effective and efficient synthetic route is presented and investigated by this work for the production of PODEn, which are formed from methylal and trioxane with low water content (<10 %(mass)) over HZSM-5 catalyst in a batch slurry autoclave at the temperature from 353.15 K to 393.15 K. The reaction rate laws including the PODEnand byproducts of polyoxymethylene hemiformals (HFn), polyoxymethylene glycols (MG), methanol (MeOH) and methyl formate (MF) are developed. The rate constants of propagation step (k6) and depolymerization step (k−6) are assumed independent on polymerization degree of PODEn. The rate of reaction is proportional to the content of the catalyst (Wcat) for the catalytic reaction within the scope of the study. All kinetic parameters were estimated by combining genetic algorithm and least square regression to fit experimental data well. This work is valuable for process optimization and reactor design.

3,3′,5,5′-Tetramethylbenzidine (TMB) is one of the traditional enzyme substrates that has been widely used in the fields of artificial enzyme mimics and natural enzymes. However, the development of TMB-based probes for fluorescence and colorimetric dual models remains a great challenge. Herein, we developed a facile method to fabricate a colorimetric and fluorescent nanoswitch based on near-infrared fluorescent TMB dots (TMBDs) for the reversible recognition (CFRR) of Fe3+and Cys. The proposed CFRR nanoswitch was based on an oxidation–reduction mechanism by which the TMBDs are oxidized by Fe3+to form ensembles and Cys reduces the ensembles to TMBDs. The CFRR nanoswitch exhibited high sensitivity for the colorimetric and fluorescent recognition of Fe3+with limits of detection (LODs) of 0.17 μM and 7.5 μM and of Cys with LODs of 0.1 μM and 1.5 μM, respectively. The response speed was very fast, within 5 min. Moreover, two output signals, namely near-infrared fluorescent and colorimetric, were exhibited in this CFRR sensor; the recognition was reversible and retained good stability after three cycles. It is noteworthy to mention that the CFRR nanoswitch performed successfully in urine, and molecular logic gate systems were readily established. Therefore, these investigations will shed light on the development of multi-mode output signals for nanoprobes.

We developed a facile and feasible fluorescent nanoswitch assay for reversible recognition of glutamate (Glu) and Al3+in human serum and living cell. The proposed nanoswitch assay is based on our recently developed method for controlled synthesis of fluorescent polydopamine dots (PDADs) at room temperature with dopamine as the sole precursor. The fluorescence of nanoswitch assay could be quickly and efficiently quenched by Glu (turn-Off), and the addition of Al3+could recover the fluorescence of the PDADs–Glu system (turn-On). Meanwhile, the reversible recognition of Glu and Al3+in this nanoswitch system was stable after three cycles. Additionally, the system displayed excellent performance for Glu and Al3+determination with a low detection limit of 0.12 and 0.2 μM, respectively. Moreover, PDADs are successfully applied to determine Glu and monitor Al3+in human serum. Noteworthy, the nanoswitch assay is transported into HepG2 cells and realized “Off” detection of Glu and “On” sensing Al3+in the living cells. Therefore, this PDADs-based nanoswitch assay provides a strategy to develop reversible recognition biosensors for intracellular and external molecular analysis.

Understanding the evolution of brown carbon (BrC) in the atmosphere is essential for investigating its climate effects. This study deployed a novel in‐situ BrC continuous observation system to firstly measure water‐soluble BrC absorption (AbsWS‐BrC) in an offshore island over the Bohai Sea in the winter of 2020. The AbsWS‐BrCabundance before the cold wave (BCW) was more than twice higher than that after the cold wave (ACW). This was mainly ascribed to the substantially suppressed formation of secondary WS‐BrC (WS‐BrCsec). Diurnal patterns of AbsWS‐BrCexhibited nighttime peaks, which derived from enhanced primary emissions and strong aqueous‐phase processes. Photochemical processes bleached daytime WS‐BrC during BCW, while daytime peaks of WS‐BrCsecemerged during ACW due to the weakened photobleaching effect. Statistical analysis indicated ambient temperature and relative humidity as well as total oxidized nitrogen (NO2+ NO3−) and reduced nitrogen (NH4++ NH3) were the dominant factors promoting WS‐BrCsec. Moderate aerosol pH (>2.5) also facilitated the formation of WS‐BrCsecwhile no obvious dependences of WS‐BrCsecon gas‐particle partitioning of ammonia, O3, and sulfur precursors were found. At the molecular level, BrC chromophores with the identified compositions, carbon oxidation state, O/C, H/C, and absorption spectra were compared between the two periods. Characteristics of water‐soluble CHO‐ and CHON‐BrC were more of secondary origin during BCW, while primary emissions contributed significantly to BrC chromophores during ACW. This study highlights the advantage of high resolution BrC measurement in probing its dynamic evolution and influencing factors. Brown carbon (BrC) has been identified as an important short‐lived climate forcer and plays a substantial role in climate change. In this study, hourly water‐soluble BrC was measured by a novel in‐situ continuous observation system at an offshore island over the Bohai Sea. Quantitative separation of secondary versus primary water‐soluble BrC was achieved. Primary water‐soluble BrC showed nighttime peaks due to the enhanced anthropogenic emissions. The high values of secondary water‐soluble BrC in daytime depended on the relative strength of photochemical production versus photobleaching. Higher ambient temperature, relative humidity, and higher concentrations of nitrogen‐containing precursors were identified as the facilitating factors for the secondary formation of water‐soluble BrC. The high‐resolution mass spectrometry analysis provided more detailed information on the molecular compositions of BrC, which showed different characteristics before and after the cold wave. Higher temperature, relative humidity, and oxidized/reduced nitrogen precursors promoted secondary formation of water‐soluble brown carbon (BrC)Daytime peaks of secondary water‐soluble BrC depended on the relative strength of photochemical production versus photobleachingSecondary water‐soluble BrC was strongly suppressed after the cold wave, evidenced by its molecular composition characterization Higher temperature, relative humidity, and oxidized/reduced nitrogen precursors promoted secondary formation of water‐soluble brown carbon (BrC) Daytime peaks of secondary water‐soluble BrC depended on the relative strength of photochemical production versus photobleaching Secondary water‐soluble BrC was strongly suppressed after the cold wave, evidenced by its molecular composition characterization

The sources, transmission routes and effects on human health of soil ARGs are summarized, and the mechanism of soil ARGs control by biochar is discussed on the basis of the positive effects by biochar.The ways in which biochar affects soil ARGs are analyzed in several directions (soil physicochemical properties, heavy metal content, antibiotic content, microbial structure and enzyme activity) in an attempt to provide a basis for the next studies.The mechanisms of biochar in the regulation of antibiotics and heavy metals for soil ARGs removal are systematically and comprehensively described, while also prospecting the potential application of biochar in soil ARGs removal.

Amines/aminiums are recognized for their importance in new particle formation, organic nitrogen cycle, and aerosol forcings. Among the complex sources, the ocean origins and generation pathways of aminiums are less understood. During a cruise campaign over the Chinese marginal sea (Bohai Sea), five low‐molecular‐weight aminiums were measured. The strong anthropogenic period (terrestrial transport) and the weak anthropogenic period (dust, clean, and sea fog periods) were identified based on the traceable aerosol chemical species, air masses transport patterns, and marine chlorophyll‐a. Inconsistent spatiotemporal variations of various aminiums were observed. Monomethylaminium (MMAH+), dimethylaminium (DMAH+), ethylaminium (EAH+), and diethylaminium (DEAH+) were more enriched during the weak anthropogenic period than the strong anthropogenic period and especially peaked during the sea fog period. The significant correlation between the four aminiums and methanesulfonic acid suggested their secondary formation pathways. Through further exploring the governing factors, the acid–base neutralization via the aqueous phase processing was identified as a critical process for the secondary transformation of aminiums. In contrast, trimethylaminium (TMAH+) showed moderate correlation with Na+in the total suspended particles only, suggesting its primary marine sources via enrichment in the sea‐spray aerosol through bubble bursting. Based on the step‐wise correlation analysis, the sea surface organic nitrogenous reservoir was found as the dominant contributor to the measured aminiums over the Bohai Sea, while the role of marine phytoplankton emission in the formation of aminiums was limited. Amines have been identified as key species in the formation processes of atmospheric particles, which may further have an impact on climate change. In the marine atmosphere, amines can be emitted from the seawater, while the emission pathway and formation mechanism of different amines are still unclear. It is also ambiguous whether the main contributor of amines over the ocean is dominated by the seawater organic nitrogenous reservoir or the marine phytoplankton emission. In this study, five common particulate aminiums were measured over the Bohai Sea. All aminiums largely originated from ocean during the weak anthropogenic influence period. However, inconsistent spatiotemporal variations and different correlations with some traceable atmospheric chemical components among various aminiums indicated their different emission pathways from the seawater, including seawater bubble bursting and air–sea exchange. For those amines emitted from the latter, the acid–base neutralization in the aqueous phase was identified as a critical process for the emitted gaseous amines to be transformed into their particulate phase. Besides, we found the seawater organic nitrogen reservoir as the dominant contributor to the measured aminiums, overwhelming the influence from the marine phytoplankton emission. Atmospheric aminiums were emitted from the ocean through different pathways, that is, sea spray and secondary formationThe acid–base neutralization via the aqueous phase processing was critical for the secondary transformation of aminiumsThe sea surface organic nitrogenous reservoir was found as the dominant contributor to the measured aminiums over the Bohai Sea Atmospheric aminiums were emitted from the ocean through different pathways, that is, sea spray and secondary formation The acid–base neutralization via the aqueous phase processing was critical for the secondary transformation of aminiums The sea surface organic nitrogenous reservoir was found as the dominant contributor to the measured aminiums over the Bohai Sea

In order to avoid increasing the solution scale caused by adding nodes in the process of dealing with corners, a new corner treatment in 3D time-domain boundary element method is proposed. Without increasing the number of nodes, based on the constant trace of the strain tensor at corners, auxiliary equations relevant to the displacement and traction at corners are established to solve the traction discontinuity at corners. Not limited by prescribed boundary displacement and traction at corners, the proposed corner treatment is good at handling complex boundary conditions with arbitrary combinations of displacements and tractions. In addition, without increasing the nodes or adjusting the positions of nodes, the formulation of the 3D time-domain boundary element method based on the corner treatment is maneuverable in coupling with other numerical methods. The correctness of the presented corner treatment in 3D time-domain boundary element method is verified by two examples.

Sea salts act as an important medium for atmospheric processing. One intensive field campaign in the September–October period of 2019 was conducted at a subtropical coastal site over the South China Sea. Unexpected high concentrations of acidic gaseous precursors were observed, yielding high sulfate in PM2.5. Na+ranked as the third highest inorganic species, about half of NH4+. Significant cation deficiency was found due to the ammonia‐poor environment. Diel patterns of most air pollutants from land breeze were stronger than that from marine breeze and presented pronounced unimodal distributions, which were ascribed to complex chemical processing mixed with regional transport. Thermodynamic equilibrium model (ISORROPIA II) simulation revealed sea salts could be internally mixed with fine particle secondary species and suggested evident multiphase reactions on sea salts. The simulated aerosol pH reached as low as 1.63 ± 0.50, which was related to high sulfate, insufficient alkaline species, and low aerosol liquid water content. During a continuous sea breeze episode, SO42−was underpredicted by 2.89 ± 3.85 μg m−3if Na+was not considered in ISORROPIA simulation. The retrieved Na+‐related ion pairs (NaCl, NaHSO4, and Na2SO4) accounted for about one‐fourth of the total inorganic aerosols. This study highlighted that intense atmospheric processing on sea salts occurred in fine particles and the mixing state between sea salts and other aerosol species should be considered in aerosol acidity prediction and secondary aerosol formation in coastal regions. Sea salts were internally mixed with the secondary species even in fine particle, suggesting evident multiphase reactions on sea saltsAerosol pH was very low at the land‐sea interface and it depended on the relative strengths of sea salts versus terrestrial ammonia emissionsThe retrieved chemical forms of SO42−contained a substantial contribution from bisulfate, mainly in the form of NaHSO4and NH4HSO4 Sea salts were internally mixed with the secondary species even in fine particle, suggesting evident multiphase reactions on sea salts Aerosol pH was very low at the land‐sea interface and it depended on the relative strengths of sea salts versus terrestrial ammonia emissions The retrieved chemical forms of SO42−contained a substantial contribution from bisulfate, mainly in the form of NaHSO4and NH4HSO4