Research on flux of dry atmospheric falling dust and its characterization in a subtropical city, Guangzhou, South China

Guangzhou is the central city in the Pearl River Delta (PRD), China, and is one of the most polluted cities in the world. To characterize the ambient falling dust pollution, two typical sampling sites: urban (Wushan) and suburban (University Town) areas in Guangzhou city were chosen for falling dust collection over 1 year at time intervals of 1 or 2 months. The flux of dry deposition was calculated. In addition, mineral composition and morphology of atmospheric falling dust were studied by X-ray diffraction, scanning electron microscopy, and microscopic observation. The results revealed that the dust flux in Guangzhou city was 3.34–3.78 g/(m2 month) during the study period. The main minerals in the dust were quartz, illite, calcite, kaolinite, gypsum, plagioclase, dolomite, and amorphous matter. The morphological types included grained and flaky individual minerals, chain-like aggregates, spherical flying beads, and irregular aggregates, with the chain-like and spherical aggregates indicators of industrial ash. The major dusts were derived from industrial and construction activities. The gypsum present in the dust collected in winter season was not only derived from cement dust but may also have originated from the reaction of calcic material with sulfuric acids resulting from photooxidation of SOx and NOx, which confirmed serious air pollution due to SOx and NOx in Guangzhou. The abatement of fossil fuel combustion emissions and construction dust will have a significant beneficial effect on dust reduction

Emission of PAHs, NPAHs and OPAHs from residential honeycomb coal briquette combustion

Coal combustion is one of the most significant sources of air pollution in China. In this study, emission factors (EFs) of 15 polycyclic aromatic hydrocarbons (PAHs), 26 nitrated PAHs (NPAHs) and 6 oxygenated PAHs (OPAHs) were determined in five different coals with different geological maturity (vitrinite reflectance <i>R</i>_O = 0.77–1.88%) burned in the form of honeycomb briquettes. The total EFs ranged from 9.82 to 215 mg kg^–1 for PAHs, 0.14 to 1.88 mg kg^–1 for NPAHs and 4.47 to 20.8 mg kg^–1 for OPAHs. Measured EFs and gas-particle partitioning varied depending on the geological maturity. The lowest EFs were found in anthracite. The proportion of PAHs, NPAHs and OPAHs in gaseous phase increasing with increased geological maturity. The coal with higher geological maturity produced more 3-ring PAHs. On the basis of the statistical analysis for the residential sector of China in 2008, PAHs, NPAHs and OPAHs emitted from residential honeycomb coal briquettes were 4.36 Gg, 0.03 Gg and 0.47 Gg in 2007, respectively. By 2020, the emission would decrease to 2.18 Gg, 0.02 Gg and 0.24 Gg for PAHs, NPAHs and OPAHs due to the increasing usage of new energy resources. If only anthracite is used as the residential coal, 93% PAHs, 87% NPAHs and 71% OPAHs would be reduced in 2020

Application of insect-proof nets in pesticide-free rice creates an altered microclimate and differential agronomic performance

Background Insect-proof nets are commonly used in crop production and scientific research because of their environmental, economic, and agronomic benefits. However, insect-proof nets can unintentionally alter the microclimate inside the screenhouse and therefore greatly affect plant growth and yield. To examine the microclimate and agronomic performance of pesticide-free rice under insect-proof nets, two-year field experiments were carried out in 2011 and 2012. Methods In the present study, the experiment was conducted by using a split-plot design considering the cultivation environment (open field cultivation (OFC) and insect-proof nets cultivation (IPNC)) as the main plot and the varieties as the subplot (Suxiangjing3 and Nanjing44). Results IPNC significantly reduced the air speed and solar radiation, and slightly increased the daytime soil temperature, daytime air temperature, and nighttime relative humidity. By contrast, the nighttime soil temperature, nighttime air temperature, and daytime relative humidity were relatively unaffected. The grain yield of both rice cultivars decreased significantly under IPNC, which was largely attributed to the reduced panicle number. The reduced panicle number was largely associated with the decreased maximum tiller number, which was positively correlated with the tillering rate, time of tillering onset, and tillering cessation for both rice cultivars under IPNC. In addition, dry matter accumulation significantly decreased for both rice cultivars under IPNC, which was mainly caused by the decreased leaf area duration resulting from the reduced leaf area index. By contrast, the mean net assimilation rate was relatively unaffected by IPNC. Discussion Insect-proof nets altered the microclimate in comparison with OFC by reducing the air speed and changing the radiation regime, which significantly affected dry matter production and yield of both japonica rice cultivars. Our results indicated that cultivation measures that could increase the tillering rate and the maximum tiller number under IPNC would lead to a significant increase in panicle number, ultimately increasing grain yield. In addition, maintaining a high leaf area duration by increasing the leaf area index would be important to compensate for the dry matter accumulation losses under IPNC. These findings are critical to provide a theoretical basis for improving agronomic performance of pesticide-free rice under IPNC

The roles of SMYD4 in epigenetic regulation of cardiac development in zebrafish

SMYD4 belongs to a family of lysine methyltransferases. We analyzed the role of smyd4 in zebrafish development by generating a smyd4 mutant zebrafish line (smyd4L544Efs*1) using the CRISPR/Cas9 technology. The maternal and zygotic smyd4L544Efs*1 mutants demonstrated severe cardiac malformations, including defects in left-right patterning and looping and hypoplastic ventricles, suggesting that smyd4 was critical for heart development. Importantly, we identified two rare SMYD4 genetic variants in a 208-patient cohort with congenital heart defects. Both biochemical and functional analyses indicated that SMYD4(G345D) was pathogenic. Our data suggested that smyd4 functions as a histone methyltransferase and, by interacting with HDAC1, also serves as a potential modulator for histone acetylation. Transcriptome and bioinformatics analyses of smyd4L544Efs*1 and wild-type developing hearts suggested that smyd4 is a key epigenetic regulator involved in regulating endoplasmic reticulum-mediated protein processing and several important metabolic pathways in developing zebrafish hearts

Measurement report: Molecular characteristics of cloud water in southern China and insights into aqueous-phase processes from Fourier transform ion cyclotron resonance mass spectrometry

Characterizing the molecular composition of cloud water could provide unique insights into aqueous chemistry. Field measurements were conducted at Mt. Tianjing in southern China in May, 2018. There are thousands of formulas (C$_{5-30}$H$_{4-55}$O$_{1-15}$N$_{0-2}$S$_{0-2}$) identified in cloud water by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). CHON formulas (formulas containing C, H, O, and N elements; the same is true for CHO and CHOS) represent the dominant component (43.6 %–65.3 % of relative abundance), followed by CHO (13.8 %–52.1%). S-containing formulas constitute ∼5 %–20 % of all assigned formulas. Cloud water has a relative-abundance-weighted average O/C of 0.45–0.56, and the double bond equivalent of 5.10–5.70. Most of the formulas (>85 %) are assigned as aliphatic and olefinic species. No statistical difference in the oxidation state is observed between cloud water and interstitial PM$_{2.5}$. CHON with aromatic structures are abundant in cloud water, suggesting their enhanced in-cloud formation. Other organics in cloud water are mainly from biomass burning and oxidation of biogenic volatile organic compounds. The cloud water contains more abundant CHON and CHOS at night, which are primarily contributed by −N$_{2}$O$_{5}$ function and organosulfates, demonstrating the enhanced formation in dark aqueous or multi-phase reactions. While more abundant CHO is observed during the daytime, likely due to the photochemical oxidation and photolysis of N- or S-containing formulas. The results provide an improved understanding of the in-cloud aqueous-phase reactions

Impact of in-cloud aqueous processes on the chemical compositions and morphology of individual atmospheric aerosols

The composition, morphology, and mixing structure of individual cloud residues (RES) and interstitial particles (INT) at a mountaintop site were investigated. Eight types of particles were identified, including sulfate-rich (S-rich), S-organic matter (OM), aged soot, aged mineral dust, aged fly ash, aged metal, refractory, and aged refractory mixture. A shift of dominant particle types from S-rich (29 %) and aged soot (27 %) in the INT to aged refractory mixture (23 %) and S-OM (22 %) in the RES is observed. In particular, particles with organic shells are enriched in the RES (27 %) relative to the INT (12 %). Our results highlight that the formation of more oxidized organic matter in the cloud contributes to the existence of organic shells after cloud processing. The fractal dimension (D$_{f}$), a morphologic parameter to represent the branching degree of particles, for soot particles in the RES (1.82 ± 0.12) is lower than that in the INT (2.11 ± 0.09), which indicates that in-cloud processes may result in less compact soot. This research emphasizes the role of in-cloud processes in the chemistry and microphysical properties of individual particles. Given that organic coatings may determine the particle hygroscopicity, activation ability, and heterogeneous chemical reactivity, the increase of OM-shelled particles upon in-cloud processes should have considerable implications

Engineering human ventricular heart muscles based on a highly efficient system for purification of human pluripotent stem cell-derived ventricular cardiomyocytes

Background Most infarctions occur in the left anterior descending coronary artery and cause myocardium damage of the left ventricle. Although current pluripotent stem cells (PSCs) and directed cardiac differentiation techniques are able to generate fetal-like human cardiomyocytes, isolation of pure ventricular cardiomyocytes has been challenging. For repairing ventricular damage, we aimed to establish a highly efficient purification system to obtain homogeneous ventricular cardiomyocytes and prepare engineered human ventricular heart muscles in a dish. Methods The purification system used TALEN-mediated genomic editing techniques to insert the neomycin or EGFP selection marker directly after the myosin light chain 2 (MYL2) locus in human pluripotent stem cells. Purified early ventricular cardiomyocytes were estimated by immunofluorescence, fluorescence-activated cell sorting, quantitative PCR, microelectrode array, and patch clamp. In subsequent experiments, the mixture of mature MYL2-positive ventricular cardiomyocytes and mesenchymal cells were cocultured with decellularized natural heart matrix. Histological and electrophysiology analyses of the formed tissues were performed 2 weeks later. Results Human ventricular cardiomyocytes were efficiently isolated based on the purification system using G418 or flow cytometry selection. When combined with the decellularized natural heart matrix as the scaffold, functional human ventricular heart muscles were prepared in a dish. Conclusions These engineered human ventricular muscles can be great tools for regenerative therapy of human ventricular damage as well as drug screening and ventricular-specific disease modeling in the future. Electronic supplementary material The online version of this article (doi:10.1186/s13287-017-0651-x) contains supplementary material, which is available to authorized users

Repair of Adult Mammalian Heart After Damages by Oral Intake of Gu Ben Pei Yuan San

Adult mammalian heart repair after myocardial damage is highly inefficient due to the post-mitotic nature of cardiomyocytes. Interestingly, in traditional Chinese medicine (TCM), there are reported effective treatments of myocardial infarction (MI) and heart failure in adult humans by oral intake of a TCM concoction named Gu Ben Pei Yuan San (GBPYS), which is composed of Panax ginseng, velvet antler, Gekko gecko Linnaeus tail, human placenta, Trogopterus dung, Panax notoginseng, and amber. We fed mice with GBPYS after myocardial damages through everyday self-feeding. We then examined the effect of everyday oral intake of GBPYS on improving cardiac function and myocardial repair in adult mice after apical resection or MI. We found that long-term oral intake of GBPYS significantly improved cardiac function after myocardial damages in adult mice. BrdU, phospho-histone 3, and AuroraB staining indicated increased cell proliferation at the border zone of MI after TCM feeding. GBPYS feeding reduced organ inflammation, induced angiogenesis, and is non-toxic to mice after long-term oral intake. Further, serum derived from TCM-fed MI rats promoted division of both neonatal rat cardiomyocytes and human induced pluripotent stem cell (iPSC)-derived cardiomyocytes in vitro. Oral intake of GBPYS improved heart repair after myocardial damages in adult mice. Our results suggest that there are substances present in GBPYS that help improve adult mammalian heart repair after MI. Also, it could be a good choice of non-invasive alternative therapy for myocardial damages and heart failure after rigorous clinical study in the future

Linker-extended native cyanovirin-N facilitates PEGylation and potently inhibits HIV-1 by targeting the glycan ligand

Cyanovirin-N (CVN) potently inhibits human immunodeficiency virus type 1 (HIV-1) infection, but both cytotoxicity and immunogenicity have hindered the translation of this protein into a viable therapeutic. A molecular docking analysis suggested that up to 12 residues were involved in the interaction of the reverse parallel CVN dimer with the oligosaccharide targets, among which Leu-1 was the most prominent hot spot residue. This finding provided a possible explanation for the lack of anti-HIV-1 activity observed with N-terminal PEGylated CVN. Therefore, linker-CVN (LCVN) was designed as a CVN derivative with a flexible and hydrophilic linker (Gly4Ser)3 at the N-terminus. The N-terminal α-amine of LCVN was PEGylated to create 10 K PEG-aldehyde (ALD)-LCVN. LCVN and 10 K PEG-ALD-LCVN retained the specificity and affinity of CVN for high mannose N-glycans. Moreover, LCVN exhibited significant anti-HIV-1 activity with attenuated cytotoxicity in the HaCaT keratinocyte cell line and MT-4 T lymphocyte cell lines. 10 K PEG-ALD-LCVN also efficiently inactivated HIV-1 with remarkably decreased cytotoxicity and pronounced cell-to-cell fusion inhibitory activity in vitro. The linker-extended CVN and the mono-PEGylated derivative were determined to be promising candidates for the development of an anti-HIV-1 agent. This derivatization approach provided a model for the PEGylation of biologic candidates without introducing point mutations. © 2014 Chen et al

QKI is a critical pre-mRNA alternative splicing regulator of cardiac myofibrillogenesis and contractile function

The RNA-binding protein QKI belongs to the hnRNP K-homology domain protein family, a well-known regulator of pre-mRNA alternative splicing and is associated with several neurodevelopmental disorders. Qki is found highly expressed in developing and adult hearts. By employing the human embryonic stem cell (hESC) to cardiomyocyte differentiation system and generating QKI-deficient hESCs (hESCs-QKIdel) using CRISPR/Cas9 gene editing technology, we analyze the physiological role of QKI in cardiomyocyte differentiation, maturation, and contractile function. hESCs-QKIdel largely maintain normal pluripotency and normal differentiation potential for the generation of early cardiogenic progenitors, but they fail to transition into functional cardiomyocytes. In this work, by using a series of transcriptomic, cell and biochemical analyses, and the Qki-deficient mouse model, we demonstrate that QKI is indispensable to cardiac sarcomerogenesis and cardiac function through its regulation of alternative splicing in genes involved in Z-disc formation and contractile physiology, suggesting that QKI is associated with the pathogenesis of certain forms of cardiomyopathies