Macrophages enhance regeneration of lateral line neuromast derived from interneuromast cells through TGF-ß in zebrafish.

Macrophages play a pivotal role in the response to injury, contributing significantly to the repair and regrowth of damaged tissues. The external lateral line system in aquatic organisms offers a practical model for studying regeneration, featuring interneuromast cells connecting sensory neuromasts. Under normal conditions, these cells remain dormant, but their transformation into neuromasts occurs when overcoming inhibitory signals from Schwann cells and posterior lateral line nerves. The mechanism enabling interneuromast cells to evade inhibition by Schwann cells remains unclear. Previous observations suggest that macrophages physically interact with neuromasts, nerves, and Schwann cells during regeneration. This interaction leads to the regeneration of neuromasts in a subset of zebrafish with ablated neuromasts. To explore whether macrophages achieve this effect through secreted cytokines, we conducted experiments involving tail amputation in zebrafish larvae and tested the impact of cytokine inhibitors on neuromast regeneration. Most injured larvae remarkably regenerated a neuromast within 4 days post-amputation. Intriguingly, removal of macrophages and inhibition of the anti-inflammatory cytokine transforming growth factor-beta (TGF-ß) significantly delayed neuromast regeneration. Conversely, inhibition of the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) had minor effects on the regeneration process. This study provides insights into how macrophages activate interneuromast cells, elucidating the pathways underlying neuromast regeneration.

Potential natural product 3,4-seco-schitriterpenoids from Kadsura japonica L. as anti-neuroinflammatory agents.

In the present study, the undescribed schitriterpenoids, kadsujanonols A-I (1-9), and eleven reported compounds (10-20) were isolated from K. japonica L. vines. Their structures of 3,4-seco-schitriterpenoids were elucidated mainly by spectroscopic analyses including 1H-, 13C-, and 2D-NMR, IR, HRESIMS spectra. The spatial configurations were determined by the single-crystal X-ray diffraction analysis of kadsujapnonol A (1), 15, 17, and 18, CD data and computational analysis. Furthermore, all isolates were evaluated for the anti-neuroinflammatory activity on LPS-stimulated NO production in BV2 microglial cells and compounds 2, 4, 5, 7, 9, 11, 13-16, and 18 exposed better or comparable suppression abilities than PDTC. Among them, kadlongilactone B (14) showed the best significant inhibiting ability (IC50 = 0.87 µg/mL) and the effect is through the attenuation of the inflammatory transcription factor p65NF-κB. Preliminary structure-activity relationship revealed that δ-lactone at the side chain and 7-member lactone at C-3/C-4, and 3,4:9,10 ring opening are important.

Favoring the Selective H2O2 Generation of a Self-Antibiofouling Dissolved Oxygen Sensor for Real-Time Online Monitoring via Surface-Engineered N-Doped Reduced Graphene Oxide.

Dissolved oxygen (DO) is a key parameter in assessing water quality, particularly in aquatic ecosystems. The oxygen reduction reaction (ORR) has notable prevalence in energy conversion and biological processes, including biosensing. Nevertheless, the long-term usage of the submersible DO sensors leads to undesirable biofilm formation on the electrode surface, deteriorating their sensitivity and stability. Recently, the reactive oxygen species (ROS), such as the two-electron pathway ORR byproduct, H2O2, had been known for its biofilm-degradation activity. Herein, for the first time, we reported N-doped reduced graphene oxide (N-rGO) for H2O2 selectivity as the self-antibiofouling DO sensor. Introducing foreign atom doping could reorient the electron network of graphene by the electronegativity gap, which facilitated highly selective and efficient two electron pathway of ORR. Mitigating the N content of N-rGO had enhanced the H2O2 selectivity (57.5%) and electron transfer number (n = 2.84) in neutral medium. Moreover, the N-rGO could be integrated to a wireless DO monitoring device that might realize an applicable device in the aquatic fish farming.

Anti-inflammatory effect of euphane- and tirucallane-type triterpenes isolated from the traditional herb Euphorbia neriifolia L.

The Euphorbiaceae plant Euphorbia neriifolia L. is distributed widely in India, Thailand, Southeastern China, and Taiwan and used as a carminative and expectorant to treat several inflammation-related diseases, such as gonorrhoea, asthma, and cancer. In the course of our search for potential anti-inflammatory agents from the titled plant, 11 triterpenes from the stem of E. neriifolia were isolated and reported in our previous endeavor. Given its rich abundance in triterpenoids, the ethanolic extract in this follow-up exploration has led to the isolation of additional eight triterpenes, including six new euphanes-neritriterpenols H and J-N (1 and 3-7)-one new tirucallane, neritriterpenol I (2), and a known compound, 11-oxo-kansenonol (8). Their chemical structures were elucidated on the basis of spectroscopic data, including 1D- and 2D NMR, and HRESIMS spectra. The absolute stereochemistry of neritriterpenols was determined by single-crystal X-ray diffraction analysis, ICD spectra, and DP4+ NMR data calculations. Compounds 1-8 were also evaluated for their anti-inflammatory activity by using lipopolysaccharide (LPS)-stimulated IL-6 and TNF-α on RAW 264.7 macrophage cells. Intriguingly, the euphane-type triterpenes (1 and 3-8) showed an inhibitory effect on LPS-induced IL-6 but not on TNF-α, while tirucallane-type triterpene 2 showed strong inhibition on both IL-6 and TNF-α.

NRICM101 ameliorates SARS-CoV-2-S1-induced pulmonary injury in K18-hACE2 mice model.

The coronavirus disease 2019 (COVID-19) pandemic continues to represent a challenge for public health globally since transmission of different variants of the virus does not seem to be effectively affected by the current treatments and vaccines. During COVID-19 the outbreak in Taiwan, the patients with mild symptoms were improved after the treatment with NRICM101, a traditional Chinese medicine formula developed by our institute. Here, we investigated the effect and mechanism of action of NRICM101 on improval of COVID-19-induced pulmonary injury using S1 subunit of the SARS-CoV-2 spike protein-induced diffuse alveolar damage (DAD) of hACE2 transgenic mice. The S1 protein induced significant pulmonary injury with the hallmarks of DAD (strong exudation, interstitial and intra-alveolar edema, hyaline membranes, abnormal pneumocyte apoptosis, strong leukocyte infiltration, and cytokine production). NRICM101 effectively reduced all of these hallmarks. We then used next-generation sequencing assays to identify 193 genes that were differentially expressed in the S1+NRICM101 group. Of these, three (Ddit4, Ikbke, Tnfaip3) were significantly represented in the top 30 enriched downregulated gene ontology (GO) terms in the S1+NRICM101 group versus the S1+saline group. These terms included the innate immune response, pattern recognition receptor (PRR), and Toll-like receptor signaling pathways. We found that NRICM101 disrupted the interaction of the spike protein of various SARS-CoV-2 variants with the human ACE2 receptor. It also suppressed the expression of cytokines IL-1ß, IL-6, TNF-α, MIP-1ß, IP-10, and MIP-1α in alveolar macrophages activated by lipopolysaccharide. We conclude that NRICM101 effectively protects against SARS-CoV-2-S1-induced pulmonary injury via modulation of the innate immune response, pattern recognition receptor, and Toll-like receptor signaling pathways to ameliorate DAD.

Increasing Nonfossil Fuel Contributions to Atmospheric Nitrate in Urban China from Observation to Prediction.

China's nitrogen oxide (NOx) emissions have undergone significant changes over the past few decades. However, nonfossil fuel NOx emissions are not yet well constrained in urban environments, resulting in a substantial underestimation of their importance relative to the known fossil fuel NOx emissions. We developed an approach using machine learning that is accurate enough to generate a long time series of the nitrogen isotopic composition (δ15N) of atmospheric nitrate using high-level accuracies of air pollutants and meteorology data. Air temperature was found to be the critical driver of the variation of nitrate δ15N at daily resolution based on this approach, while significant reductions of aerosol and its precursor emissions played a key role in the change of nitrate δ15N on the yearly scale. Predictions from this model found a significant decrease in nitrate δ15N in Chinese megacities (Beijing and Guangzhou as representative cities in the north and south, respectively) since 2013, implying an enhanced contribution of nonfossil fuel NOx emissions to nitrate aerosols (up to 22%-26% in 2021 from 18%-22% in 2013 quantified by an isotope mixing model), as confirmed by the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem) simulation. Meanwhile, the declining contribution in coal combustion (34%-39% in 2013 to 31%-34% in 2021) and increasing contribution of natural gas combustion (11%-14% in 2013 to 14%-17% in 2021) demonstrated the transformation of China's energy structure from coal to natural gas. This approach provides missing records for exploring long-term variability in the nitrogen isotope system and may contribute to the study of the global reactive nitrogen biogeochemical cycle.

Kaguacidine A: a novel spirohydantoin-containing cucurbitane glycoside from vines of Momordica charantia L.

The spirohydantoin-containing cucurbitane-type triterpenoid, kaguacidine A (1), was isolated and purified from 95% ethanol extract of vines of Momordica charantia L. (Cucurbitaceae). Its unprecedented chemical structure, a spirohydantoin substituent at C-23 of cucurbitane, was elucidated by extensive spectroscopic analyses, including HRESIMS, IR, optical rotation, 1 D- and 2 D-NMR spectra. The possible biosynthetic pathway is deduced and may be attributed to the metabolic activity of microbial symbionts in M. charantia L. Compound 1 was evaluated for anti-inflammatory activity against LPS-induced NO production in RAW 264.7 cells and anti-proliferative activity against four cancer cell lines, including HEp-2, MCF-7, Hep-G2, and WiDr. Compound 1 showed moderate anti-inflammatory activity with an IC50 value of 18.5 ± 0.4 µg/mL and weak anti-proliferative activity against MCF-7, HEp-2, Hep-G2, and WiDr with IC50 values of >40, 33.8 ± 0.6, 31.0 ± 0.7, and 27.0 ± 0.7 µM, respectively.

Seasonal variations of low molecular alkyl amines in PM2.5 in a North China Plain industrial city: Importance of secondary formation and combustion emissions.

Atmospheric amines have unique acid-neutralizing capacity and play an important role in atmospheric chemical reactions. An integrated observation of PM2.5 samples (from Dec 2015 to Nov 15, 2016) was conducted in a typical industrial city (Xuzhou), China. Concentrations of total measured amines (∑amines, including methylamine (MA), ethylamine (EA), dimethylamine (DMA), propanamine (PA) and trimethylamine (TMA) + diethylamine (DEA)) were 172.0 ± 98.2 ng m-3, accounting 1.5 ± 0.6 ‰ of PM2.5 mass. ∑amines were higher in winter (249.0 ± 112.3 ng m-3) and spring (192.4 ± 75.9 ng m-3) than in summer (114.7 ± 33.3 ng m-3) and autumn (103.7 ± 34.3 ng m-3). Concentrations of MA and EA (the dominant amines) were highest in winter, while DMA, PA and TMA + DEA showed opposite seasonality. EA/MA ratios ranged from 0.04 to 8.7 with a median value of 0.3, and the averaged EA/MA ratio was 2.0 in winter, indicating large contribution of EA. Environmental factors including temperature (T), relative humidity (RH) and atmospheric oxidizing capacity (O3 and Ox represented) were found to influence concentrations of amines in PM2.5. The Positive Matrix Factorization (PMF) model identified secondary products (41.6 %), combustion emissions (39.8 %), soil and waste incineration emissions (13.2 %) and biological emissions and aging products (5.4 %) as the 4 sources of amines in PM2.5. MA was mainly secondary products (82.5 %) and had high contribution of local secondary formation, while EA was mainly derived from combustion emissions (83.7 %) and influenced by regional transportation. In winter, combustion emissions (including coal combustion, biomass burning and traffic emissions, contributed 57.7 %) surpassed secondary products (31.6 %) as the predominant sources of amines, especially under the influence of regional transportation (75.7 %).

New ent-kaurene and germacrene derivatives from Mesona procumbens Hemseley and their biological activity.

Mesona procumbens Hemseley is a well-known traditional herbal medicine used for heat-related ailments. In Taiwan, boiled extracts of M. procumbens are also used as desserts called grass jelly. In this study, the hexane extract from 75% EtOH of M. procumbens showed potent activities on inhibition of E. coli ß-glucuronidase (eßG) and NO production and cytotoxicity against MCF-7 and HepG2 cancer cell lines. Furthermore, using various flash columns and HPLC chromatography on the bioactive layer led to the isolation of twelve compounds (1-12), including a new ent-kaurene, mesokaurol A (1), and a new germacrene derivative, mesogermapene A (2). Their structures were elucidated by extensive spectroscopic analyses, especially 2 D NMR and mass data. Biological assays showed that compound 9 (linolenic acid) had specific activity on inhibition of eßG (68.27%) at 100 µg/mL but was non-inhibitory to human ß-glucuronidase. Compound 1 possessed significant cytotoxicity against MCF-7 (EC50 = 9.76 µM) and HepG2 (EC50 = 8.64 µM) cancer cell lines.

Components with Anti-Diabetic Activity Isolated from the Leaves and Twigs of Glycosmis pentaphylla Collected in Vietnam.

A phytochemical investigation of the leaves and twigs of Glycosmis pentaphylla (Rutaceae), collected in Vietnam, yielded three new compounds named glyfuran (1), glyphyllamide (2), and glyphyllazole (3), along with twenty-five known compounds (4-28). The structures of isolates were determined by IR, MS, NMR, and UV data analyses. In the anti-diabetic activity screening, (+)-isoaltholacton (4), glycoborinine (17), 2',4'-dihydroxy-4,6'-dimethoxychalcone (24), and flavokawain A (25) simultaneously exhibited inhibition of dipeptidyl peptidase-4 (DPP4) and stimulation of the glucagon-like peptide-1 (GLP-1) secretion on the murine intestinal secretin tumor cell line (STC-1).

Anti-inflammatory sesquiterpene and triterpene acids from Mesona procumbens Hemsley.

Mesona procumbens Hemsley is a plant conventionally processed to provide popular food materials and herbal medicines in Asia. In this study, six triterpene acids, including five new ones (mesonaic acids D-H, 1-5), and one proximadiol-type sesquiterpene (7) were isolated from the methanolic extract of the air-dried M. procumbens. Chemical structures of 1‒7 were established by spectroscopic methods, especially 2D NMR techniques (1H-1H COSY, HSQC, HMBC, and NOESY) and HRESIMS. Concerning their biological activities, compounds 1, 2, 6, and 7 were examined manifesting high inhibition toward the pro-inflammatory NO production with EC50 values ranging from 12.88 to 21.21 µM, outrunning the positive control quercetin (24.12 µM). The mesoeudesmol B (7) identified from M. procumbens is the very first example, which exhibited high anti-inflammatory activity diminishing the level of the lipopolysaccharide-induced NO in RAW264.7 macrophage cells, thereby suppressing the secretion of pro-inflammatory cytokines TNF-α and IL-6 and the level of two critical downstream inflammatory mediators iNOS and COX-2.

Targeting spike protein-induced TLR/NET axis by COVID-19 therapeutic NRICM102 ameliorates pulmonary embolism and fibrosis.

The global COVID-19 pandemic remains a critical public health threat, as existing vaccines and drugs appear insufficient to halt the rapid transmission. During an outbreak from May to August 2021 in Taiwan, patients with severe COVID-19 were administered NRICM102, which was a traditional Chinese medicine (TCM) formula developed based on its predecessor NRICM101 approved for treating mild cases. This study aimed to explore the mechanism of NRICM102 in ameliorating severe COVID-19-related embolic and fibrotic pulmonary injury. NRICM102 was found to disrupt spike protein/ACE2 interaction, 3CL protease activity, reduce activation of neutrophils, monocytes and expression of cytokines (TNF-α, IL-1ß, IL-6, IL-8), chemokines (MCP-1, MIP-1, RANTES) and proinflammatory receptor (TLR4). NRICM102 also inhibited the spread of virus and progression to embolic and fibrotic pulmonary injury through reducing prothrombotic (vWF, PAI-1, NET) and fibrotic (c-Kit, SCF) factors, and reducing alveolar type I (AT1) and type II (AT2) cell apoptosis. NRICM102 may exhibit its protective capability via regulation of TLRs, JAK/STAT, PI3K/AKT, and NET signaling pathways. The study demonstrates the ability of NRICM102 to ameliorate severe COVID-19-related embolic and fibrotic pulmonary injury in vitro and in vivo and elucidates the underlying mechanisms.

[Changes in Carbonaceous Aerosol in the Northern Suburbs of Nanjing from 2015 to 2019].

Carbonaceous aerosol is an important component of atmospheric fine particles that has an important impact on air quality, human health, and climate change. In order to explore the long-term changes in carbonaceous aerosol under the background of emission reduction, this study measured the mass concentrations of organic carbon (OC) and elemental carbon (EC) of PM2.5, which collected in the northern suburbs of Nanjing for five years (December 17, 2014 to January 5, 2020). The results showed that the five-year average ρ(OC) and ρ(EC) were (10.2±5.3) µg·m-3 and (1.6±1.1) µg·m-3, accounting for 31.1% and 5.2% of PM2.5, respectively. OC and EC concentrations were both high in winter and low in summer. According to the nonparametric Mann-Kendall test and Sen's slope, the mass concentrations of OC and PM2.5 decreased significantly[OC:P<0.0001, -0.79 µg·(m3·a)-1, -0.29%·a-1; PM2.5:P<0.0001, -4.59 µg·(m3·a)-1, -1.58%·a-1]. Although EC had an upward trend, the significance and range of change were not obvious[P=0.02, 0.05 µg·(m3·a)-1, 0.02%·a-1]. OC and EC decreased significantly during winter from 2014 to 2019[OC:P<0.0001, -2.05 µg·(m3·a)-1, -0.74%·a-1; EC:P=0.001, -0.15 µg·(m3·a)-1, -0.05%·a-1], and the decline was more obvious than the whole. The correlation between OC and EC showed that the sources in winter and summer were more complex than those in spring and autumn. According to the characteristic ratio of OC and EC, the contribution of coal combustion and biomass burning decreased from 2015 to 2019, whereas the impact of industrial sources and vehicle emissions became more significant. Corresponding to this was the obvious decline in OC and the slight recovery of EC. The OC/EC ratio was over 2.0, indicating that there was secondary pollution in the study area. Further calculation revealed that the variation in SOC was consistent with that in OC, showing a significant decrease[P<0.0001, -0.47 µg·(m3·a)-1, -0.17%·a-1]. The average mass concentration of SOC was (5.0±3.5) µg·m-3, accounting for 49.2% of OC. These changes indicate clear effects of the prevention and control of air pollution in Nanjing in recent years. Furthermore, future control can focus on the emissions of VOCs to reduce secondary pollution.

Neritriterpenols A-G, euphane and tirucallane triterpenes from Euphorbia neriifolia L. and their bioactivity.

Euphorbia neriifolia L. is widely distributed in India, Thailand, and China and has been used to treat diseases such as rotten sores and asthma as well as for its antidiabetic and anticancer effects. In this study, seven undescribed triterpenes, including six euphanes, neritriterpenols A-B and D-G, and a tirucallane, neritriterpenol C, together with four known triterpenes, were isolated from ethanolic extracts of E. neriifolia stems. Their structures with absolute configurations were determined through detailed spectroscopic data, including 1D and 2D NMR data analyses, single-crystal X-ray diffraction analysis, ECD spectra, and DP4+ NMR data calculations as well as Mo2(OAc)4-induced ECD analysis. Furthermore, preliminarily evaluation of the anti-inflammatory and anti-proliferative effects of the isolated triterpenes leads to the structure-activity relationship (SAR) studies implying that the unsaturated functional group at the end of the C17 side chain on euphane-type triterpenes may be correlated with the increase of anti-inflammatory and anti-proliferative activities.

Carbamazepine promotes surface expression of mutant Kir6.2-A28V ATP-sensitive potassium channels by modulating Golgi retention and autophagy.

Pancreatic ß-cells express ATP-sensitive potassium (KATP) channels, consisting of octamer complexes containing four sulfonylurea receptor 1 (SUR1) and four Kir6.2 subunits. Loss of KATP channel function causes persistent hyperinsulinemic hypoglycemia of infancy (PHHI), a rare but debilitating condition if not treated. We previously showed that the sodium-channel blocker carbamazepine (Carb) corrects KATP channel surface expression defects induced by PHHI-causing mutations in SUR1. In this study, we show that Carb treatment can also ameliorate the trafficking deficits associated with a recently discovered PHHI-causing mutation in Kir6.2 (Kir6.2-A28V). In human embryonic kidney 293 or INS-1 cells expressing this mutant KATP channel (SUR1 and Kir6.2-A28V), biotinylation and immunostaining assays revealed that Carb can increase surface expression of the mutant KATP channels. We further examined the subcellular distributions of mutant KATP channels before and after Carb treatment; without Carb treatment, we found that mutant KATP channels were aberrantly accumulated in the Golgi apparatus. However, after Carb treatment, coimmunoprecipitation of mutant KATP channels and Golgi marker GM130 was diminished, and KATP staining was also reduced in lysosomes. Intriguingly, Carb treatment also simultaneously increased autophagic flux and p62 accumulation, suggesting that autophagy-dependent degradation of the mutant channel was not only stimulated but also interrupted. In summary, our data suggest that surface expression of Kir6.2-A28V KATP channels is rescued by Carb treatment via promotion of mutant KATP channel exit from the Golgi apparatus and reduction of autophagy-mediated protein degradation.

Anthropogenic Emission Sources of Sulfate Aerosols in Hangzhou, East China: Insights from Isotope Techniques with Consideration of Fractionation Effects between Gas-to-Particle Transformations.

Sulfate (SO42-) is a major species in atmospheric fine particles (PM2.5), inducing haze formation and influencing Earth's climate. In this study, the δ34S values in PM2.5 sulfate (δ34S-SO42-) were measured in Hangzhou, east China, from 2015 September to 2016 October. The result showed that the δ34S-SO42- values varied from 1.6 to 6.4‰ with the higher values in the winter. The estimated fractionation factor (α34Sg→p) from SO2 to SO42- averaged at 3.9 ± 1.6‰. The higher α34Sg→p values in the winter were mainly attributed to the decrease of ambient temperature. We further compared the quantified source apportionments of sulfate by isotope techniques with and without the consideration of fractionation factors. The result revealed that the partitioned emission sources to sulfate with the consideration of the fractionation effects were more logical, highlighting that fractionation effects should be considered in partitioning emission sources to sulfate using sulfur isotope techniques. With considering the fractionation effects, coal burning was the dominant source to sulfate (85.5%), followed by traffic emissions (12.8%) and oil combustion (1.7%). However, the coal combustion for residential heating contributed only 0.9% to sulfate on an annual basis in this megacity.

Four cucurbitane glycosides taimordisins A-D with novel furopyranone skeletons isolated from the fruits of Momordica charantia.

Four novel triterpene glycosides, taimordisins A-D (1-4), were discovered from fresh fruits of Taiwanese Momordica charantia. The chemical framework and relative stereochemistry of these four natural products were isolated, purified, and determined by using various separation and spectroscopy techniques. Each of them features a unique bicyclic-fused or trifuso-centro-fused ring system. Notably, 1 and 2 are cucurbitane-based compounds possessing a new C-24 and C-2″ carbon-carbon linkage with 5-hydroxy-2-(hydroxymethyl)tetrahydro-4H-pyran-4-one and 6-(hydroxymethyl)tetrahydro-4H-pyran-3,4,4-triol units, respectively, and represented an unprecedented molecular skeleton. In terms of biosynthesis, they all originate from a common precursor 3-hydroxycucurbita-5,24-dien-19-al-7,23-di-O-ß-glucopyranoside. Of two sugar moieties, the one at 23-O-ß-glucopyranoside grants each individual congener uniqueness likely through microbial symbiont-mediated intramolecular transformation into two major types of furo[2,3-b]pyranone and furo[3,2-c]pyranone derivatives. These new products possess desirable anti-inflammatory biological activities in addition to being generally regarded as safe.

Decrease of atmospheric black carbon and CO2 concentrations due to COVID-19 lockdown at the Mt. Waliguan WMO/GAW baseline station in China.

The Coronavirus Disease 2019 (COVID-19) lockdown policy reduced anthropogenic emissions and impacted the atmospheric chemical characteristics in Chinese urban cities. However, rare studies were conducted at the high mountain site. In this work, in-situ measurements of light absorption by carbonaceous aerosols and carbon dioxide (CO2) concentrations were conducted at Waliguan (WLG) over the northeastern Tibetan Plateau of China from January 3 to March 30, 2020. The data was employed to explore the influence of the COVID-19 lockdown on atmospheric chemistry in the background-free troposphere. During the sampling period, the light absorption near-infrared (>470 nm) was mainly contributed by BC (>72%), however, BC and brown carbon (BrC) contributed equally to light absorption in the short wavelength (∼350 nm). The average BC concentrations in the pre-, during and post-lockdown were 0.28 ±â€¯0.25, 0.18 ±â€¯0.16, and 0.28 ±â€¯0.20 µg m-3, respectively, which decreased by approximately 35% during the lockdown period. Meanwhile, CO2 also showed slight decreases during the lockdown period. The declined BC was profoundly attributed to the reduced emissions (∼86%), especially for the combustion of fossil fuels. Moreover, the declined light absorption of BC, primary and secondary BrC decreased the solar energy absorbance by 35, 15, and 14%, respectively. The concentration weighted trajectories (CWT) analysis suggested that the decreased BC and CO2 at WLG were exclusively associated with the emission reduction in the eastern region of WLG. Our results highlighted that the reduced anthropogenic emissions attributed to the lockdown in the urban cities did impact the atmospheric chemistry in the free troposphere of the Tibetan Plateau.

Cucurbitane-type triterpenoids from the vines of Momordica charantia and their anti-inflammatory, cytotoxic, and antidiabetic activity.

Phytochemical investigation of the ethanol extract from wild Momordica charantia vines has resulted in isolation of seven cucurbitane-type triterpenoids, including six undescribed compounds, kuguaovins H‒M, and the known compound, momordicoside K. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, and MS experiments. The chemical structure of momordicoside K was determined for the first time by X-ray crystallographic analysis and its absolute configuration assigned. The cytotoxicity against four human tumor cell lines and anti-inflammatory activities on LPS-stimulated RAW264.7 macrophages were evaluated. Of the isolates, kaguaovin L exhibited potential cytotoxicity against MCF-7, HEp-2, Hep-G2, and WiDr cancer cell lines and showed moderate anti-NO production activity. In addition, kuguaovins H and J also showed the stimulatory effect of GLP-1 secretion on the murine intestinal secretin tumor cell line (STC-1).

Impacts of chemical degradation of levoglucosan on quantifying biomass burning contribution to carbonaceous aerosols: A case study in Northeast China.

Biomass burning (BB) is an important source of carbonaceous aerosols in Northeast China (NEC). Quantifying the original contribution of BB to organic carbon (OC) [BB-OC] can provide an essential scientific information for the policy-makers to formulate the control measures to improve the air quality in the NEC region. Daily PM2.5 samples were collected in the rural area of Changchun city over the NEC region from May 2017 to May 2018. In addition to carbon contents, BB tracers (e.g., levoglucosan and K+BB, defined as potassium from BB) were also determined, in order to investigate the relative contribution of BB-OC. The results showed that OC was the dominant (28%) components of PM2.5 during the sampling period. Higher concentrations of OC, levoglucosan, and K+BB were observed in the autumn followed by the winter, spring, and summer, indicating that the higher BB activities during autumn and winter in Changchun. By using the Bayesian mixing model, it was found that burning of crop residues were the dominant source (65-79%) of the BB aerosols in Changchun. During the sampling period, the aging in air mass (AAM) ratio was 0.14, indicating that ~86% of levoglucosan in Changchun was degraded. Without considering the degradation of levoglucosan in the atmosphere, the BB-OC ratios were 23%, 28%, 7%, and 4% in the autumn, winter, spring, and summer, respectively, which were 1.4-4.8 time lower than those (14-42%) with consideration of levoglucosan degradation. This illustrated that the relative contribution of BB to OC would be underestimated (~59%) without considering degradation effects of levoglucosan. Although some uncertainty was existed in our estimation, our results did highlight that the control of straw burning was an efficient way to decrease the airborne PM2.5, improving the air quality in the NEC plain.