scholarly journals Contributions of Ammonia to High Concentrations of PM2.5 in an Urban Area

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1676
Author(s):  
Junsu Park ◽  
Eunhye Kim ◽  
Sangmin Oh ◽  
Haeri Kim ◽  
Soontae Kim ◽  
...  
Keyword(s):  
Urban Area ◽  
Critical Role ◽  
Three Dimensional ◽  
Water Soluble ◽  
Urban Site ◽  
High Concentrations ◽  
Total Ratio ◽  
Pm2.5 Concentration ◽  
Measurement Period

Atmospheric ammonia (NH3) plays a critical role in PM2.5 pollution. Data on atmospheric NH3 are scanty; thus, the role of NH3 in the formation of ammonium ions (NH4+) in various environments is understudied. Herein, we measured concentrations of NH3, PM2.5, and its water-soluble SO42−, NO3−, and NH4+ ions (SNA) at an urban site in Jeonju, South Korea from May 2019 to April 2020. During the measurement period, the average concentrations of NH3 and PM2.5 were 10.5 ± 4.8 ppb and 24.0 ± 12.8 μg/m3, respectively, and SNA amounted to 4.3 ± 3.1, 4.4 ± 4.9, and 1.6 ± 1.8 μg/m3, respectively. A three-dimensional photochemical model analysis revealed that a major portion of NH3, more than 88%, originated from Korea. The enhancement of the ammonium-to-total ratio of NH3, NHX (NHR = [NH4+]/[NH4+] + [NH3]) was observed up to ~0.61 during the increase of PM2.5 concentration (PM2.5 ≥ 25 μg/m3) under low temperature and high relative humidity conditions, particularly in winter. The PM2.5 and SNA concentrations increased exponentially as NHR increased, indicating that NH3 contributed significantly to SNA formation by gas-to-particle conversion. Our study provided experimental evidence that atmospheric NH3 in the urban area significantly contributed to SNA formation through gas-to-particle conversion during PM2.5 pollution episodes.

Cationicity and hydrophobicity enhance the cytotoxic potency of Phoratoxin C anticancer peptide analogues against triple negative breast cancer cells

2021 ◽  
Vol 17 ◽  
Author(s):  
Chu Xin Ng ◽  
Cheng Foh Le ◽  
Sau Har Lee
Keyword(s):  
Cancer Cells ◽  
Anticancer Agents ◽  
Breast Cancer Cells ◽  
Critical Role ◽  
Three Dimensional ◽  
Vero Cells ◽  
Anticancer Peptides ◽  
Α Helix ◽  
Peptide Analogues

Background: Anticancer peptides (ACPs) have received increasing attention as a promising class of novel anticancer agents owing to its potent and rapid cytotoxic properties. In this study, we aim to investigate the effects of cationicity and hydrophobicity in modulating the cytotoxicity of PtxC, a class of ACP from the leafy mistletoe Phoradendron tomentosum against the MDA-MB-231 and Vero cells. Method: We designed a series of four PtxC analogues (PA1 – PA4) by residual substitutions with specific amino acids to introduce the specific charge and hydrophobicity alterations to the analogues. The cytotoxicity strength of the PtxC analogues on MDA-MB-231 and Vero cells were tested by using MTT assay at 24 hours post treatment. Results: PA1, PA2 and PA4 displayed marked increases in cytotoxicity against both MDA-MB-231 and Vero cells and can be ranked in the order of PA2 > PA4 > PA1 > PtxC > PA3. Sequence-activity relationship analyses of the designed analogues showed that an increase in the level of cationicity and hydrophobicity correlated well with the enhanced cytotoxic activity of PtxC analogues. This was observed with PA1 (netC +8) and PA2 (netC +10) in comparison to PtxC (netC +7). Similar finding was observed for PA4 (GRAVY +0.070) in contrast to PtxC (GRAVY -0.339). Three-dimensional modelling predicted a double α-helix structure in PtxC class of ACP. The larger first helix in PA2 and PA4 was suggested to be responsible for the enhanced cytotoxicity observed. Conclusion: The critical role of cationicity and hydrophobicity in enhancing cytotoxicity of PtxC class of ACPs were clearly demonstrated in our study. The current findings could be extrapolated to benefit peptide design strategy in other classes of ACPs toward the discovery of highly potent ACPs against cancer cells as potential novel therapeutic agents.

scholarly journals Critical Role of 3D ultrasound in the diagnosis and management of Robert’s uterus: a single-centre case series and a review.

2021 ◽  
Vol 13 (1) ◽  
pp. 41-49
Author(s):  
M. Deenadayal ◽  
V. Günther ◽  
I. Alkatout ◽  
D. Freytag ◽  
A. Deenadayal-Mettler ◽  
...  
Keyword(s):  
Correct Diagnosis ◽  
Critical Role ◽  
Three Dimensional ◽  
Case Series ◽  
Uterine Cavity ◽  
Laparoscopic Hysterectomy ◽  
3D Ultrasound ◽  
Magnetic Resonance Imaging Mri ◽  
Treatment Procedures

A septate uterus with a non-communicating hemicavity was first described by Robert in 1969/70 as a specific malformation of the uterus. The condition is commonly associated with a blind uterine hemicavity, unilateral haematometra, a contralateral unicornuate uterine cavity and a normal external uterine fundus. The main symptoms are repetitive attacks of pain at four-weekly intervals around menarche, repeated dysmenorrhea, recurrent pregnancy loss and infertility. In this report, we review the disease, its diagnosis and treatment, and describe five cases of Robert’s uterus. Three dimensional (3D) ultrasound (US) imaging was performed by the transvaginal route in four cases. In the fifth case of a 13-year-old girl, we avoided the vaginal route and magnetic resonance imaging (MRI) and 3D transrectal US yielded the correct diagnosis. The following treatment procedures were undertaken: laparoscopic endometrectomy, hysteroscopic septum resection, laparoscopic uterine hemicavity resection and total laparoscopic hysterectomy (TLH). The diagnosis and optimum treatment of Robert’s uterus remains difficult for clinicians because of its rarity. A detailed and careful assessment by 3D US should be performed, followed by hysteroscopy in combination with laparoscopy, to confirm the diagnosis.

scholarly journals The role of traffic emissions in particulate organics and nitrate at a downwind site in the periphery of Guangzhou, China

2017 ◽  
Author(s):  
Yi Ming Qin ◽  
Hao Bo Tan ◽  
Yong Jie Li ◽  
Misha I. Schurman ◽  
Fei Li ◽  
...  
Keyword(s):  
Hong Kong ◽  
Southern China ◽  
Organic Aerosol ◽  
Urban Site ◽  
Strong Correlations ◽  
Automobile Emissions ◽  
Direct Emission ◽  
Multilinear Engine ◽  
High Concentrations

Abstract. Particulate matter (PM) pollution on the peripheries of rapidly expanding megacities in China can be as serious as in the cities due to direct emission and transport of primary PM from cities and effective formation of secondary PM. To investigate the emission and formation of PM on the periphery of Guangzhou (a megacity in southern China), a suite of real-time instruments were deployed at Panyu, downwind of Guangzhou, for PM measurements from November to December 2014. Dominated by organics, PM1 (particles with diameter less than 1 μm) concentrations in Panyu were higher (average ~ 55.4 μg/m3) than those in nearby cities such as Hong Kong and Shenzhen. Five sources for organic aerosols (OA) were resolved by positive matrix factorization (PMF) analysis with the multilinear engine (ME-2). These sources are hydrocarbon-like organic aerosol (HOA), cooking organic aerosol (COA), biomass burning related organic aerosol (BBOA), as well as semi-volatile oxygenated organic aerosol (SVOOA) and low-volatile oxygenated organic aerosol (LVOOA). The use of the COA mass spectrum obtained in our earlier study at a urban site in Hong Kong as a constraining factor in ME-2 produced the most interpretable results for the Panyu dataset. Freshly emitted HOA contributed 40 % to the high concentrations of organics at night. The mass concentration of SOA (SVOOA + LVOOA) continuously increased as odd oxygen (Ox = O3 + NO2) increased during daytime, attributable to the secondary production of PM facilitated by photochemistry. The SOA-to-Ox ratio was higher than those reported in previous studies in North America (covering the period from spring to summer), indicating efficient photochemical production of SOA even in late autumn and early winter at this subtropical downwind site. The efficient SOA formation during daytime was likely fueled by the sufficient SOA precursors in the atmosphere. The large input of NOx, which tracked well with HOA from automobile emissions, resulted in the significant formation of nitrate in both daytime and nighttime. Strong correlations between particulate nitrate and excess ammonium ([NH4+]/[SO42−] − 1.5) × [SO42−]) were observed. Higher partitioning of nitrate into the gas phase was found in November than in December, likely due to the lower temperatures in December. Results from this study suggest that there is much room to mitigate the PM pollution in urbanized areas such as Guangzhou, as well as their peripheries, by reductions in traffic-related pollutants.

scholarly journals Redirecting differentiation of mammary progenitor cells by 3D bioprinted sweat gland microenvironment

2019 ◽  
Vol 7 ◽  
Author(s):  
Rui Wang ◽  
Yihui Wang ◽  
Bin Yao ◽  
Tian Hu ◽  
Zhao Li ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Cell Fate ◽  
Sweat Gland ◽  
Critical Role ◽  
Three Dimensional ◽  
Control Group ◽  
Specific Marker ◽  
Shh Pathway

Abstract Background Mammary progenitor cells (MPCs) maintain their reproductive potency through life, and their specific microenvironments exert a deterministic control over these cells. MPCs provides one kind of ideal tools for studying engineered microenvironmental influence because of its accessibility and continually undergoes postnatal developmental changes. The aim of our study is to explore the critical role of the engineered sweat gland (SG) microenvironment in reprogramming MPCs into functional SG cells. Methods We have utilized a three-dimensional (3D) SG microenvironment composed of gelatin-alginate hydrogels and components from mouse SG extracellular matrix (SG-ECM) proteins to reroute the differentiation of MPCs to study the functions of this microenvironment. MPCs were encapsulated into the artificial SG microenvironment and were printed into a 3D cell-laden construct. The expression of specific markers at the protein and gene levels was detected after cultured 14 days. Results Compared with the control group, immunofluorescence and gene expression assay demonstrated that MPCs encapsulated in the bioprinted 3D-SG microenvironment could significantly express the functional marker of mouse SG, sodium/potassium channel protein ATP1a1, and tend to express the specific marker of luminal epithelial cells, keratin-8. When the Shh pathway is inhibited, the expression of SG-associated proteins in MPCs under the same induction environment is significantly reduced. Conclusions Our evidence proved the ability of differentiated mouse MPCs to regenerate SG cells by engineered SG microenvironment in vitro and Shh pathway was found to be correlated with the changes in the differentiation. These results provide insights into regeneration of damaged SG by MPCs and the role of the engineered microenvironment in reprogramming cell fate.

scholarly journals Structural basis of the heterodimerization of the MST and RASSF SARAH domains in the Hippo signalling pathway

2014 ◽  
Vol 70 (7) ◽  
pp. 1944-1953 ◽  
Author(s):  
Eunha Hwang ◽  
Hae-Kap Cheong ◽  
Ameeq Ul Mushtaq ◽  
Hye-Yeon Kim ◽  
Kwon Joo Yeo ◽  
...  
Keyword(s):  
Structural Information ◽  
Critical Role ◽  
Three Dimensional ◽  
Helical Structure ◽  
Structural Features ◽  
Signalling Pathway ◽  
Structural Basis ◽  
X Ray Crystallography ◽  
Hippo Signalling

Despite recent progress in research on the Hippo signalling pathway, the structural information available in this area is extremely limited. Intriguingly, the homodimeric and heterodimeric interactions of mammalian sterile 20-like (MST) kinases through the so-called `SARAH' (SAV/RASSF/HPO) domains play a critical role in cellular homeostasis, dictating the fate of the cell regarding cell proliferation or apoptosis. To understand the mechanism of the heterodimerization of SARAH domains, the three-dimensional structures of an MST1–RASSF5 SARAH heterodimer and an MST2 SARAH homodimer were determined by X-ray crystallography and were analysed together with that previously determined for the MST1 SARAH homodimer. While the structure of the MST2 homodimer resembled that of the MST1 homodimer, the MST1–RASSF5 heterodimer showed distinct structural features. Firstly, the six N-terminal residues (Asp432–Lys437), which correspond to the short N-terminal 310-helix h1 kinked from the h2 helix in the MST1 homodimer, were disordered. Furthermore, the MST1 SARAH domain in the MST1–RASSF5 complex showed a longer helical structure (Ser438–Lys480) than that in the MST1 homodimer (Val441–Lys480). Moreover, extensive polar and nonpolar contacts in the MST1–RASSF5 SARAH domain were identified which strengthen the interactions in the heterodimer in comparison to the interactions in the homodimer. Denaturation experiments performed using urea also indicated that the MST–RASSF heterodimers are substantially more stable than the MST homodimers. These findings provide structural insights into the role of the MST1–RASSF5 SARAH domain in apoptosis signalling.

Role of PKC and calcium in modulation of effects of angiotensin II on sodium transport in proximal tubule

2003 ◽  
Vol 284 (4) ◽  
pp. F688-F692 ◽  
Author(s):  
Zhaopeng Du ◽  
William Ferguson ◽  
Tong Wang
Keyword(s):  
Proximal Tubule ◽  
Intracellular Calcium ◽  
Critical Role ◽  
Proximal Tubules ◽  
Ang Ii ◽  
Fluid Absorption ◽  
Physiological Concentration ◽  
High Concentrations

It has been well documented that low concentrations of ANG II (10−11 to 10−10 M) stimulate, whereas high concentrations of ANG II (10−8 to 10−5 M) inhibit Na+transport in proximal tubules of rat and rabbit kidneys. Measured ANG II concentration in proximal tubular fluid is in the nanomolar range. In the present study, we investigated the role of PKC, intracellular Ca2+, and cAMP in modulating the effects of luminal ANG II on Na+ absorption by microperfusion techniques in rabbit superficial segment of proximal tubules in vitro. We confirmed that ANG II (10−9 M) had no change on fluid absorption ( J v); however, fluid absorption increased significantly when 10−9 M ANG II and 3,4,5-trimethoxybenzoic acid-8-(diethylamino)octyl ester (TMB-8), a blocker of intracellular calcium mobilization, were added together. In contrast, ANG II significantly decreased J v when PKC was inhibited. When 10−9 M ANG II was present together with 1-(5-isoquinolinesulfonyl)-2-mehtylpiperazine and TMB-8, no significant change of J v occurred. Inhibition of endogenous cAMP activity by a PKA inhibitor did not change either basal or ANG II-stimulated fluid absorption. Our results indicate that ANG II regulates Na+ absorption by a cAMP-independent mechanism and that PKC and intracellular calcium both play a critical role in modulating the effects of physiological concentration of ANG II on proximal tubule transport. Balance between these two cytosolic messengers modulates the effects of ANG II on fluid absorption in the proximal tubule.

scholarly journals Importance of gas-particle partitioning of ammonia in haze formation in the rural agricultural environment

2020 ◽  
Vol 20 (12) ◽  
pp. 7259-7269 ◽  
Author(s):  
Jian Xu ◽  
Jia Chen ◽  
Na Zhao ◽  
Guochen Wang ◽  
Guangyuan Yu ◽  
...  
Keyword(s):  
Fine Particles ◽  
Critical Role ◽  
Feedback Mechanism ◽  
Water Soluble ◽  
Formation Mechanisms ◽  
Haze Pollution ◽  
Inorganic Species ◽  
High Ammonia ◽  
Haze Formation

Abstract. Ammonia in the atmosphere is essential for the formation of fine particles that impact air quality and climate. Despite extensive prior research to disentangle the relationship between ammonia and haze pollution, the role of ammonia in haze formation in high ammonia-emitting regions is still not well understood. Aiming to better understand secondary inorganic aerosol (sulfate, nitrate, ammonium – SNA) formation mechanisms under high-ammonia conditions, 1-year hourly measurement of water-soluble inorganic species (gas and particle) was conducted at a rural supersite in Shanghai. Exceedingly high levels of agricultural ammonia, constantly around 30 µg m−3, were observed. We find that gas-particle partitioning of ammonia (ε(NH4+)), as opposed to ammonia concentrations, plays a critical role in SNA formation during the haze period. From an assessment of the effects of various parameters, including temperature (T), aerosol water content (AWC), aerosol pH, and activity coefficient, it seems that AWC plays predominant regulating roles for ε(NH4+). We propose a self-amplifying feedback mechanism associated with ε(NH4+) for the formation of SNA, which is consistent with diurnal variations in ε(NH4+), AWC, and SNA. Our results imply that a reduction in ammonia emissions alone may not reduce SNA effectively, at least at rural agricultural sites in China.

scholarly journals Myosin IIA–mediated forces regulate multicellular integrity during vascular sprouting

2019 ◽  
Vol 30 (16) ◽  
pp. 1974-1984 ◽  
Author(s):  
Christine Yoon ◽  
Colin Choi ◽  
Sarah Stapleton ◽  
Teodelinda Mirabella ◽  
Caroline Howes ◽  
...  
Keyword(s):  
Network Formation ◽  
Critical Role ◽  
Three Dimensional ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Cell Contractility ◽  
Surrounding Matrix ◽  
Contractile Forces ◽  
Cell Cell

Angiogenic sprouting is a critical process involved in vascular network formation within tissues. During sprouting, tip cells and ensuing stalk cells migrate collectively into the extracellular matrix while preserving cell–cell junctions, forming patent structures that support blood flow. Although several signaling pathways have been identified as controlling sprouting, it remains unclear to what extent this process is mechanoregulated. To address this question, we investigated the role of cellular contractility in sprout morphogenesis, using a biomimetic model of angiogenesis. Three-dimensional maps of mechanical deformations generated by sprouts revealed that mainly leader cells, not stalk cells, exert contractile forces on the surrounding matrix. Surprisingly, inhibiting cellular contractility with blebbistatin did not affect the extent of cellular invasion but resulted in cell–cell dissociation primarily between tip and stalk cells. Closer examination of cell–cell junctions revealed that blebbistatin impaired adherens-junction organization, particularly between tip and stalk cells. Using CRISPR/Cas9-mediated gene editing, we further identified NMIIA as the major isoform responsible for regulating multicellularity and cell contractility during sprouting. Together, these studies reveal a critical role for NMIIA-mediated contractile forces in maintaining multicellularity during sprouting and highlight the central role of forces in regulating cell–cell adhesions during collective motility.

scholarly journals Temporal and Spatial Variation of PM2.5 in Xining, Northeast of the Qinghai–Xizang (Tibet) Plateau

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 953 ◽  
Author(s):  
Xiaofeng Hu ◽  
Yongzheng Yin ◽  
Lian Duan ◽  
Hong Wang ◽  
Weijun Song ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Spatial Variation ◽  
Average Concentration ◽  
Water Soluble ◽  
Salt Lakes ◽  
Urban Site ◽  
Annual Average ◽  
Annual Average Concentration ◽  
Oxidation Ratio ◽  
Pm2.5 Concentration

PM2.5 was sampled from January 2017 to May 2018 at an urban, suburban, industrial, and rural sites in Xining. The annual mean of PM2.5 was highest at the urban site and lowest at the rural site, with an average of 51.5 ± 48.9 and 26.4 ± 17.8 μg·m−3, respectively. The average PM2.5 concentration of the industrial and suburban sites was 42.8 ± 27.4 and 37.2 ± 23.7 μg·m−3, respectively. All sites except for the rural had concentrations above the ambient air quality standards of China (GB3095-2012). The highest concentration of PM2.5 at all sites was observed in winter, followed by spring, autumn, and summer. The concentration of major constituents showed statistically significant seasonal and spatial variation. The highest concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and water-soluble inorganic ions (WSIIs) were found at the urban site in winter. The average concentration of F− was higher than that in many studies, especially at the industrial site where the annual average concentration of F− was 1.5 ± 1.7 μg·m−3. The range of sulfur oxidation ratio (SOR) was 0.1–0.18 and nitrogen oxidation ratio (NOR) was 0.02–0.1 in Xining. The higher SO42−/NO3− indicates that coal combustion has greater impact than vehicle emissions. The results of the potential source contribution function (PSCF) suggest that air mass from middle- and large-scale transport from the western areas of Xining have contributed to the higher level of PM2.5. On the basis of the positive matrix factorization (PMF) model, it was found that aerosols from salt lakes and dust were the main sources of PM2.5 in Xining, accounting for 26.3% of aerosol total mass. During the sandstorms, the concentration of PM2.5 increased sharply, and the concentrations of Na+, Ca2+ and Mg2+ were 1.13–2.70, 1.68–4.41, and 1.15–5.12 times higher, respectively, than annual average concentration, implying that aerosols were mainly from dust and the largest saltwater lake, Qinghai Lake, and many other salt lakes in the province of Qinghai. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was utilized to study the surface components of PM2.5 and F− was found to be increasingly distributed from the surface to inside the particles. We determined that the extremely high PM2.5 concentration appears to be due to an episode of heavy pollution resulting from the combination of sandstorms and the burning of fireworks.

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