Highly time-resolved chemical speciation and source apportionment of organic aerosol components in Delhi, India, using extractive electrospray ionization mass spectrometry

In recent years, the Indian capital city of Delhi has been impacted by very high levels of air pollution, especially during winter. Comprehensive knowledge of the composition and sources of the organic aerosol (OA), which constitutes a substantial fraction of total particulate mass (PM) in Delhi, is central to formulating effective public health policies. Previous source apportionment studies in Delhi identified key sources of primary OA (POA) and showed that secondary OA (SOA) played a major role but were unable to resolve specific SOA sources. We address the latter through the first field deployment of an extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF) in Delhi, together with a high-resolution aerosol mass spectrometer (AMS). Measurements were conducted during the winter of 2018/19, and positive matrix factorization (PMF) was used separately on AMS and EESI-TOF datasets to apportion the sources of OA. AMS PMF analysis yielded three primary and two secondary factors which were attributed to hydrocarbon-like OA (HOA), biomass burning OA (BBOA-1 and BBOA-2), more oxidized oxygenated OA (MO-OOA), and less oxidized oxygenated OA (LO-OOA). On average, 40 % of the total OA mass was apportioned to the secondary factors. The SOA contribution to total OA mass varied greatly between the daytime (76.8 %, 10:00–16:00 local time (LT)) and nighttime (31.0 %, 21:00–04:00 LT). The higher chemical resolution of EESI-TOF data allowed identification of individual SOA sources. The EESI-TOF PMF analysis in total yielded six factors, two of which were primary factors (primary biomass burning and cooking-related OA). The remaining four factors were predominantly of secondary origin: aromatic SOA, biogenic SOA, aged biomass burning SOA, and mixed urban SOA. Due to the uncertainties in the EESI-TOF ion sensitivities, mass concentrations of EESI-TOF SOA-dominated factors were related to the total AMS SOA (i.e. MO-OOA + LO-OOA) by multiple linear regression (MLR). Aromatic SOA was the major SOA component during the daytime, with a 55.2 % contribution to total SOA mass (42.4 % contribution to total OA). Its contribution to total SOA, however, decreased to 25.4 % (7.9 % of total OA) during the nighttime. This factor was attributed to the oxidation of light aromatic compounds emitted mostly from traffic. Biogenic SOA accounted for 18.4 % of total SOA mass (14.2 % of total OA) during the daytime and 36.1 % of total SOA mass (11.2 % of total OA) during the nighttime. Aged biomass burning and mixed urban SOA accounted for 15.2 % and 11.0 % of total SOA mass (11.7 % and 8.5 % of total OA mass), respectively, during the daytime and 15.4 % and 22.9 % of total SOA mass (4.8 % and 7.1 % of total OA mass), respectively, during the nighttime. A simple dilution–partitioning model was applied on all EESI-TOF factors to estimate the fraction of observed daytime concentrations resulting from local photochemical production (SOA) or emissions (POA). Aromatic SOA, aged biomass burning, and mixed urban SOA were all found to be dominated by local photochemical production, likely from the oxidation of locally emitted volatile organic compounds (VOCs). In contrast, biogenic SOA was related to the oxidation of diffuse regional emissions of isoprene and monoterpenes. The findings of this study show that in Delhi, the nighttime high concentrations are caused by POA emissions led by traffic and biomass burning and the daytime OA is dominated by SOA, with aromatic SOA accounting for the largest fraction. Because aromatic SOA is possibly more toxic than biogenic SOA and primary OA, its dominance during the daytime suggests an increased OA toxicity and health-related consequences for the general public.</p

Equal abundance of summertime natural and wintertime anthropogenic Arctic organic aerosols

Organic aerosols in the Arctic are predominantly fuelled by anthropogenic sources in winter and natural sources in summer, according to observations from eight sites across the Arctic Aerosols play an important yet uncertain role in modulating the radiation balance of the sensitive Arctic atmosphere. Organic aerosol is one of the most abundant, yet least understood, fractions of the Arctic aerosol mass. Here we use data from eight observatories that represent the entire Arctic to reveal the annual cycles in anthropogenic and biogenic sources of organic aerosol. We show that during winter, the organic aerosol in the Arctic is dominated by anthropogenic emissions, mainly from Eurasia, which consist of both direct combustion emissions and long-range transported, aged pollution. In summer, the decreasing anthropogenic pollution is replaced by natural emissions. These include marine secondary, biogenic secondary and primary biological emissions, which have the potential to be important to Arctic climate by modifying the cloud condensation nuclei properties and acting as ice-nucleating particles. Their source strength or atmospheric processing is sensitive to nutrient availability, solar radiation, temperature and snow cover. Our results provide a comprehensive understanding of the current pan-Arctic organic aerosol, which can be used to support modelling efforts that aim to quantify the climate impacts of emissions in this sensitive region.Peer reviewe

Metastable states from multinucleon excitations in Tl 202 and Pb 203

The excited level structures of Tl202 and Pb203, above the 7+ and 29/2- isomers, respectively, have been studied. An isomer with Iπ=20+ and T1/2=215(10)μs has been established in Tl202, and the level scheme extended from I=10 to 20ℏ with the placement of fifteen new transitions. In Pb203, the Iπ=37/2+ state is established to be metastable, with T1/2=2.5(3)ns. Levels in both nuclei arise from intrinsic excitations, with likely particle-hole character for the higher-lying states in Pb203. The 20+ isomer in Tl202 is most likely associated with a πh11/2-1 - ν(i13/2-2,f5/2-1) configuration, while the 37/2+ state in Pb203 results from the excitation of five neutrons. Calculations, using both an empirical approach and the oxbash code, have been performed to aid in the description of the excited level structure

Analysis of major and trace elements in ambient aerosols and their sources in European and Asian cities

Atmospheric aerosols comprise a wide range of solid or liquid particles suspended in our atmosphere, contributing significantly to air pollution. Besides climate effects by scattering, absorption and modification of cloud properties, aerosols show negative acute and long-term health effects. Moreover, the negative impacts of aerosols on health are enhanced in heavily urbanized areas, especially in India and China, due to increased emissions from a wide array of sources and high population density. In order to develop effective mitigation strategies, the quantification and characterization of emission sources is an essential precondition. Aerosols are a complex mixture of thousands of individual compounds, among them elements or metals which have a high degree of source specificity and chemical stability, making them powerful chemical species for aerosol source apportionment (SA) studies. In this work, we exploited the use of a recently developed near real time ambient metals monitor (Xact, based on X-ray fluorescence spectrometry) across Europe (Härkingen, Switzerland, and Krakow, Poland) and Asia (Beijing, China, and Delhi, India) to measure highly time-resolved (30 min to 1 h) elemental data in different particulate matter size ranges (PM10 and PM2.5). In the first study, an advanced statistical SA technique was applied on the Härkingen dataset to explore the first use of an Xact for SA in Europe where the concentrations are considerably lower than in Asia. The SA results from this data revealed a strong influence from the secondary sulfate, followed by traffic emissions and dust-related (road and background) emissions, while lower contributions came from sea salt and industrial emissions. In addition to that, fireworks-related factors captured during the Swiss National Day celebration were also resolved. The comparison of elemental concentrations in European and Asian cities was the focus in the second study. Extremely high concentrations of elements were observed in Delhi as compared to Beijing and European cities. This study showed that the elements can be broadly classified into five groups on a global scale: dust-related (Si, Ca, Ti, Sr), traffic (Ba, Zr, Mn, Fe, Ni), solid fuel combustion (K), traffic/industrial (Cu), industrial/coal/waste burning emissions (Pb, Zn, S, Cl, Br). In addition to that, a strong enrichment of toxic elements was observed in these cities. In the third study, we developed a combined method to investigate sources and their potential source regions in the Delhi urban atmosphere. The SA analysis identified nine sources: S-rich, dust-related, brake wear, two for solid fuel combustion, and four for plume-like events. The analyses revealed strong source contribution enhancements during late night until early morning, consistent with enhanced emissions in stagnant ambient conditions. Furthermore, the dust-related and brake wear factors were strongly enriched in elemental PM10 while the remaining factors were mostly dominant in elemental PM2.5

Serum alkaline phosphatase in oral squamous cell carcinoma and its association with clinicopathological characteristics

Context: Biochemical changes occur in biological fluids and tissues of different types of malignancies. Tumor markers in serum, tissue, and other body fluids during neoplastic process are of clinical value in the management of patients with cancers. Serum alkaline phosphatase (ALP) activity is potentially a useful indicator for detection of malignancies, but its status in oral squamous cell carcinoma (OSCC) is less explored. Aims: The aim of this study is to evaluate the serum level of ALP in OSCC patients and assess its relation with the clinicopathological features. Settings and Design: A total of 175 participants (145 OSCC patients and 30 healthy controls) were included in the study. One hundred and forty-five patients with OSCC who underwent treatment at our institution were included to obtain the clinicopathological data. Materials and Methods: Fasting blood ALP activity was evaluated using ALP assessment kit and biochemistry analyzer. Statistical Analysis Used: The data were analyzed by SPSS-21 software (SPSS Statistics for Windows, Version 21.0, Armonk, NY, USA), using t-test, Mann–Whitney U, and Kruskal–Wallis tests. Results: Raised ALP was seen in 24% of OSCC patients. The mean ALP in OSCC was significantly higher than the control. ALP level in patients with advanced stage was significantly higher than with early stage. The serum ALP level in OSCC patients with bone involvement (BI) by local extension of tumor was significantly higher than without BI. Conclusion: ALP showed statistically significant differences in relation to tumor stages and BI. Hence, ALP could be useful in advanced stage disease for expressing the endurance of patient and tumor expansion. Elevated ALP in OSCC patients may indicate BI

Large reccurent gingival growth in the maxilla: A case report

Gingival growths are one of the frequently encountered types of lesion in the oral cavity. It is the common site for neoplastic and nonneoplastic lesions. Peripheral ossifying fibroma (POF) is one of the inflammatory reactive hyperplasias of the gingiva. It represents a separate clinical entity with diverse histopathological features. Even after adequate surgical excision of the lesion, repeated recurrence is not uncommon. Studies show a recurrence rate of 16-20% in these lesions. The suggested etiology for POF is low-grade irritation due to plaque and calculus. Proper excision of such overgrowths and appropriate oral hygiene instructions will ensure that the lesion does not recur. This case report is of a large, solitary gingival swelling in the maxilla of a 36-year-old male patient that had recurred for the third time after the surgical excision

PHYTOCHEMICAL SCREENING AND IN VITRO ANTIMICROBIAL AND ANTIFUNGAL ACTIVITY OF BERGENIA LIGULATA (WALL.) LEAVES EXTRACTS

Objective: Evaluation of Antimicrobial and Antifungal potential of Phytoconstituents present in leaf extracts of Bergenia ligulata (wall.) plant. Methods: The antimicrobial effects of leaves of Bergenia ligulata (wall.) were evaluated using both ethanol and aqueous extracts against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Penicillium spp. Agar well diffusion method was employed in determining the antimicrobial activity and the broth dilution method for determining the Minimum Inhibitory Concentration. All the isolates examined were susceptible to both the ethanol, aqueous, and the combined aqueous and ethanol extracts (synergetic effect) of the Bergenia ligulata leaves. Results: The zone of inhibition ranged from 6.93 ±0.02b mm to 12.81 ±0.03a mm with Escherichia coli being the most susceptible at 12.81 ±0.03a mm to the ethanol and 11.53 ±0.02a mm to the aqueous extracts at 250 mg/ml concentration while P. aeruginosa and Penicillin spp. were the slightest susceptible at 10.88 ±0.02a mm to the ethanol and 09.76 ±0.02a mm to the aqueous extract at 250 mg/ml concentration. The control/standard antimicrobial agent (Gentamicin and Metronidazole) exhibited higher inhibitory activity than the plant extracts. The least inhibitory value of 6.25 mg/ml was produced against P. aeruginosa by the ethanolic extract and against C. albicans by the combined (aqueous and ethanol) extracts of the plant. The qualitative and quantitative phytochemical screening of the leaves of Bergenia ligulata reveals the presence of flavonoids, tannins, saponins, alkaloids, and steroids. The most abundant percentage composition observed was flavonoids (7.72%) while tannins had the least component (4.29%). Conclusion: The findings from this study show that the leaves extracts hold considerable antimicrobial activity against commonly encountered microorganisms in the environment. This therefore, implies that it can be used as a chemotherapeutic agent which will contribute to the development of antibiotic drugs against the test organisms

Association of primary open-angle glaucoma with systemic hypertension

Open-angle glaucoma is a slowly progressive neurodegeneration of retinal ganglion cells and their axonscharacterized by a specific pattern of optic nerve head and visual field damage. Glaucoma is probably one of the most prominentocular outcomes of systemic hypertension (HTN). In the light of foregoing background and considering glaucoma havingprobable association with systemic HTN, the present study was undertaken. Materials and Methods: This study was donein a tertiary care hospital over a period of 18 months, after the ethical clearance and informed written consent of the patients.All individuals above 40 years of age regardless of gender were included in the study. Included patients underwent detailedocular and systemic history and detailed examination which included visual acuity by Snellen drum, refraction, intraocularpressure by Schiotz tonometer, gonioscopy using Zeiss four-mirror lens to evaluate the anterior chamber, visual field changesseen by Humphrey field analyzer, slit-lamp examination, fundus evaluation by both direct and indirect ophthalmoscopy, and90D lens with special attention to glaucomatous fundus changes using optical coherence tomography (OCT) with Cirrus SDOCT Carl Zeiss Meditec. Apart from ocular examination, patient’s blood pressure was taken with sphygmomanometer, anddemographic and anthropometric details were also noted. Result: A case-control study was conducted on 510 individuals ofage 40 years and above, irrespective of sex. Out of them, 340 (66.7%) patients were hypertensives with systemic blood pressureof &gt;140/90 mmHg, whereas 170 (33.3%) patients were non-hypertensives so were taken as controls. On looking for the presenceof glaucoma in both the groups, it was observed that 13.8% of cases and 5.9% of controls had signs of glaucoma (P = 0.003,χ2= 8.58). On the further distribution of glaucoma into established and preclinical type, we found that 53.19% of glaucomatouscases and 70% of glaucomatous controls had established glaucoma (P = 0.150), while 46.8% and 30% were having preclinicalglaucoma, respectively (P = 0.020). Conclusion: A positive association was seen between HTN and primary open-angleglaucoma (POAG) prevalence. A significant difference in the distribution pattern of different clinical signs of POAG betweenhypertensives and controls was observed. The findings show that regardless of pathophysiology operating for development ofglaucoma, the clinical manifestation does not vary significantly between normotensives and hypertensives. Optic disc changesand as a result field changes are more pronounced among hypertensives as compared to normotensives, though the analysisstatistically is not significant. Thus, patients of systemic HTN are at high risk of glaucoma as HTN is contributing to bothphysiological as well as pathological damage