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1.
Sci Rep ; 14(1): 14528, 2024 Jun 24.
Article in English | MEDLINE | ID: mdl-38914618

ABSTRACT

Spatial and temporal shifts in rainfall patterns over South Asia and the adjoining Seas during the pre-monsoon season have been observed over the past 2 decades from 2000 to 2019. Aerosol particles suspended above the boundary layer are a contributing factor to these changes. These particles not only alter cloud characteristics, but also diminish the lapse rate, thereby suppressing convective activity, leading to precipitation anomalies. Over the past 2 decades, high-rainfall regions have experienced declining rainfall, while low-rainfall regions have received increased rainfall. Coinciding with notable anomalies in precipitation, contrasting trends in aerosol optical depth, particularly due to absorbing aerosols in the elevated regions of the atmosphere, are seen. Apart from aerosols, several factors are considered that are critical in modifying precipitation patterns over the study region, such as water vapor content, convective processes, and lower-level relative humidity. We observed a potential transport of excess water vapor by ambient circulation from the oceanic regions having reduced rain, such as Bay of Bengal and the Arabian Sea, to higher latitudes enabling precipitation anomaly at distant locations.

2.
Sci Rep ; 14(1): 6265, 2024 03 15.
Article in English | MEDLINE | ID: mdl-38490998

ABSTRACT

The genus Melia is known for its secondary metabolites and recently, this genus is being explored for its timber. There are vast differences among its species. For instance, Melia azedarach is reported to be invasive and while another species, M. dubia, has diverse utility with complex germination and regeneration characteristics. Researchers globally have been working on various aspects of this genus; In this study, using topic modelling and science mapping approach, we attempted to understand research facets on this genus. The literature corpus of the Web of Science database was explored using a single keyword-"Melia" which yielded 1523 publications (1946-2022) and after scrutiny metadata of 1263 publications were used in the study. Although nine individual species were cited in the publications, only three species are accepted viz., M. dubia, M. azedarach, and M. volkensii. This implies taxonomic uncertainty, with potential confusion in assigning scientific findings to particular species. Thus, a taxonomic relook on this genus is warranted for a better assessment of the economic utility in many countries. More importantly, our results indicate that the research interests have recently shifted from the secondary metabolite constituents towards growth, biomass, wood properties, germination, plantation, and green synthesis. The shift in research focus toward wood properties of Melia sp. can impact the wood demand-supply at a global scale owing to its fast growth and the possibility of cultivation over a wider geographical range.


Subject(s)
Melia azedarach , Melia , Wood , Biomass
3.
J Neurosci Methods ; 405: 110085, 2024 May.
Article in English | MEDLINE | ID: mdl-38387804

ABSTRACT

BACKGROUND: Immunohistochemistry (IHC) is an important technique in understanding the expression of neurochemical molecules in the developing human brain. Despite its routine application in the research and clinical setup, the IHC protocol specific for soft fragile fetal brains that are fixed using the non-perfusion method is still limited in studying the whole brain. NEW METHOD: This study shows that the IHC protocols, using a chromogenic detection system, used in animals and adult humans are not optimal in the fetal brains. We have optimized key steps from Antigen retrieval (AR) to chromogen visualization for formalin-fixed whole-brain cryosections (20 µm) mounted on glass slides. RESULTS: We show the results from six validated, commonly used antibodies to study the fetal brain. We achieved optimal antigen retrieval with 0.1 M Boric Acid, pH 9.0 at 70°C for 20 minutes. We also present the optimal incubation duration and temperature for protein blocking and the primary antibody that results in specific antigen labeling with minimal tissue damage. COMPARISON WITH EXISTING METHODS: The IHC protocol commonly used for adult human and animal brains results in significant tissue damage in the fetal brains with little or suboptimal antigen expression. Our new method with important modifications including the temperature, duration, and choice of the alkaline buffer for AR addresses these pitfalls and provides high-quality results. CONCLUSION: The optimized IHC protocol for the developing human brain (13-22 GW) provides a high-quality, repeatable, and reliable method for studying chemoarchitecture in neurotypical and pathological conditions across different gestational ages.


Subject(s)
Antigens , Formaldehyde , Humans , Animals , Immunohistochemistry , Antigens/metabolism , Antibodies , Brain/metabolism , Tissue Fixation/methods
4.
World Neurosurg ; 181: 52-58, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37839576

ABSTRACT

BACKGROUND: Patients in low- and middle-income countries (LMICs) have substantial treatment abandonment and non-adherence with outpatient oral medications. This work sought to investigate outcomes of postoperative discitis treated with debridement and a novel technique focused on reducing outpatient antibiotic requirement in an LMIC setting. METHODS: This study, conducted and reported following STROBE guidelines, reviewed outcomes of all patients with postoperative discitis who had been debrided by 1 neurosurgeon in a resource-limited setting during 2008-2020. Patients had undergone single-level L4-L5 or L5-S1 discectomy elsewhere, later developing magnetic resonance imaging-confirmed discitis. After non-response or deterioration following intravenous antibiotics, patients underwent early debridement, followed by in-patient antibiotic instillation into disc space for 2 weeks via drain. Study outcomes were modified Kirkaldy-Willis Grade, Japan Orthopaedic Association (JOA) score, and visual analog scale (VAS) score, all assessed at 1 year. RESULTS: Twelve patients were included, 10 male and 2 female, with median age of 46 (IQR 3.5) years. Debridement was done after median 82.5 (IQR 35) days and took median time of 105 (IQR 17.5) minutes. VAS scores (mean ± SD) decreased from 9.25 ± 0.75 preoperatively to 0.67 ± 0.89 1 year postoperatively (mean difference 8.58, 95% CI 8.01-9.15, P < 0.001). JOA scores (mean ± SD) improved from 4.5 ± 2.94 to 26.42 ± 1.31 1 year postoperatively (mean difference 21.92, 95% CI 20.57-23.26, P < 0.001). Kirkaldy-Willis grade was excellent in 6 (50%) patients, good in 5 (41.7%), and fair in 1 (8.3%). Patients became ambulatory within 2 weeks, with no major complications during 4.15 (IQR 3.45) years of median follow-up. CONCLUSIONS: In LMICs, patients with medically refractory postoperative discitis potentially have good outcomes after debridement plus 2-week local antibiotic instillation.


Subject(s)
Discitis , Humans , Male , Female , Child, Preschool , Discitis/drug therapy , Discitis/surgery , Lumbar Vertebrae/surgery , Anti-Bacterial Agents/therapeutic use , Debridement/methods , Resource-Limited Settings , Retrospective Studies , Treatment Outcome
5.
Chemosphere ; 345: 140516, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37879370

ABSTRACT

Azo dyes are the most varied class of synthetic chemicals with non-degradable characteristics. They are complex compounds made up of many different parts. It was primarily utilized for various application procedures in the dyeing industry. Therefore, it's crucial to develop an economical and environmentally friendly approach to treating azo dyes. Our present investigation is an integrated approach to the electrooxidation (EO) process of azo dyes using RuO2-IrO2-TiO2 (anode) and titanium mesh (cathode) electrodes, followed by the biodegradation process (BD) of the treated EO dyes. Chemical oxygen demand (COD) removal efficiency as follows MB (55%) ≥ MR (45%) ≥ TB (38%) ≥ CR (37%) correspondingly. The fragment generated during the degradation process which was identified with high-resolution mass spectrometry (HRMS) and its degradation mechanism pathway was proposed as demethylation reaction and N-N and C-N/C-S cleavage reaction occurs during EO. In biodegradation studies by Aeromonas hydrophila AR1, the EO treated dyes were completely mineralized aerobically which was evident by the COD removal efficiency as MB (98%) ≥ MR (92.9%) ≥ TB (88%) ≥ CR (87%) respectively. The EO process of dyes produced intermediate components with lower molecular weights, which was effectively utilized by the Aeromonas hydrophila AR1 and resulted in higher degradation efficiency 98%. We reported the significance of the enhanced approach of electrochemical oxidation with biodegradation studies in the effective removal of the pollutants in dye industrial effluent contaminated water environment.


Subject(s)
Aeromonas hydrophila , Water Pollutants, Chemical , Azo Compounds/chemistry , Oxidation-Reduction , Titanium/chemistry , Coloring Agents/chemistry , Electrodes , Water Pollutants, Chemical/analysis
6.
Cureus ; 15(8): e44477, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37791173

ABSTRACT

Paediatric amputation is one of the treatment options for various indications, namely, trauma, infection, tumour and congenital problems, and some may be born with congenital problems. It differs from adult amputation as they have higher physical demands, and special complications may arise. Stump overgrowth by far is the commonest complication in paediatric transosseous amputation, while varus deformity of the tibia stump was reported sparsely in the literature. The growth discrepancy of the proximal tibia and fibula physis coupled with distal tibiofibular synostosis may have resulted in proximal migration of the fibula, which later resulted in varus deformity of the stump. This will cause difficulty in prosthesis fitting and lead to painful stumps due to the pressure at the abnormal bony prominence. We report a case of congenital limb deficiencies in a 12-year-old male who was treated with below-knee amputation (BKA) and experienced progressive varus deformity of the stump that caused pain during prosthetic wear, which interfered with his gait. He had a varus deformity of 15 degrees of the stump, distal tibiofibular synostosis and proximal migration of the fibula head. As the conservative management by modification of the prosthesis had failed, he underwent open wedge proximal tibia corrective osteotomy, division of the synostosis and reduction of the fibula head. The surgical intervention was successful in alleviating his problem. All efforts must be made to ensure optimum prosthetic fitting in paediatric amputation patients to maintain the patient's daily lifestyle and activities.

7.
Sci Total Environ ; 901: 166461, 2023 Nov 25.
Article in English | MEDLINE | ID: mdl-37607630

ABSTRACT

Aerosol-bound water, a ubiquitous and abundant component of atmospheric aerosols, has an impact on regional climate, visibility, human health, the hydrological cycle, and atmospheric chemistry. Yet, the intricate relationship between aerosol liquid water (ALWC) and chemical composition and relative humidity (RH) was not well understood. The present study explores ALWC derived from the ISORROPIA II model using real-time, high-resolution data of non-refractory submicron chemical species and meteorological parameters (temperature and RH) collected over the Indian Ocean as part of the ICARB (Integrated Campaign for Aerosols, Gases, and Radiation Budget)-2018 experiment. Results show that ALWC values over the South Eastern Arabian Sea (SEAS) were found to be higher by 4-6 times than those observed over the Equatorial Indian Ocean (EIO) due to a large decrease in aerosol loading from SEAS to EIO. ALWC peaked in the early morning hours (4:00-7:00), with greater values during the nighttime and lower values during the daytime across SEAS, which is comparable with RH variation. While the ratio of organics-to-SO42- mass fraction linearly decreased with increasing mass-based growth factors (MGFs) over EIO, such a scenario was not observed over SEAS. The latitudinal gradient of mass fraction of ALWC had shown a decrease towards EIO, consistent with organic fraction. The extinction coefficient of the dry mass of submicron particles is noticeably increased by 40 % by ALWC over SEAS and EIO. Moreover, ALWC could enhance the aerosol negative forcing by an average of 66 % (64 %) over SEAS (EIO) at the top of the atmosphere during the cruise period. These inferences imply that ALWC is the key factor in assessing the role of aerosols on atmospheric radiative forcing. Overall, the present study highlights the serious need to consider the ALWC in climate forcing simulations, particularly in moist tropical environments where their effect can be significant.

8.
Environ Geochem Health ; 45(10): 6985-7010, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37578559

ABSTRACT

The article deals with the integrated and comprehensive study of the coal-bearing horizons from the South Karanpura Basin to delineate the biostratigraphy, palaeovegetation, palaeodepositional settings, and palaeoclimate in and around the investigated area during the deposition of Permian sediments. Highly diversified megafloral assemblages consist 13 genera and 72 species of order Glossopteridales, Cordaitales and Equisetales are documented among which 37 taxa are newly reported from Barakar and Raniganj formations of the area. Palynoassemblages-I and -II are recovered, which demonstrate the biostratigraphic age as Kungurian and Wordian-Capitanian, respectively. Overall the vegetation represents a luxuriant forest subjugated by arborescent deciduous trees bearing Glossopteris foliage with some conifers, cordaites, filicales, and peltaspermales. The biomarker study of the basin illustrates the unimodal distribution of n-alkanes in the sample set ranges from C14 to C29 which suggests major input from a single source of organic matter. The involvement of microbial activity and algal input is suggested for the basin. A relatively moderate-to-high water level condition can be inferred from elevated n-C25. The high CIA, PIA values and A-CN-K plot suggest intense weathering conditions in the source area. The source rocks are characterized by mature clayey type with abundant clay mineral, i.e., kaolinite. The current study portrays that the Permian climate was cooler in initial phase, which later on became warm temperate with high humidity. The palaeofloral entities and geochemical parameters suggest absolute diversification of Permian flora, the existence of continental freshwater setting in the vicinity and oxic to anoxic environment with fluctuating ground water conditions during the deposition of sediments.


Subject(s)
Coal , Groundwater , Plants , Weather , Water
9.
Sci Total Environ ; 900: 165644, 2023 Nov 20.
Article in English | MEDLINE | ID: mdl-37495130

ABSTRACT

Water-soluble organic carbon (WSOC) has been identified as a key component in atmospheric aerosols due to its ability to act as cloud condensation nuclei (CCN) owing to their highly hygroscopic nature. This paper discusses about the spatio-temporal variability in WSOC mass concentration, sources (primary and secondary contributions), the role of long-range air-mass transport in modulating their abundance, at distinct sectors over South Asia. We found from our observations that, photochemical ageing of primary organic aerosols that are derived from biomass emissions, significantly contribute to the total WSOC budget over South Asia. The wide range of water-soluble compounds released by biomass burning can contribute directly to the WSOC fraction or undergo further atmospheric processing, such as oxidation or ageing, leading to the formation of additional WSOC. WSOC/OC (organic carbon) ratio and the correlation between the WSOC and secondary organic carbon (SOC) are used for assessing the contribution from secondary sources. The three different ratios are used to delineate different source processes; OC/EC (elemental carbon) for source identification, WSOC/OC for long-range atmospheric transport (ageing) and WSOC/SOC to understand the primary and secondary contribution of WSOC. The present investigation revealed that, the primary OC that have undergone significant chemical processing as a result of long-range transport have a substantial influence on WSOC formation over South Asia, especially in Indo Gangetic Plain outflow regions such as southern peninsular and adjacent marine regions. Overall, oxidation and ageing of primary organic aerosols emitted from biomass burning was found to serve as an important source of WSOC over South Asia.

10.
Mar Pollut Bull ; 194(Pt B): 115339, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37517279

ABSTRACT

In order to better understand the distribution pattern, pollution degree and the submarine groundwater discharge (SGD) of dissolved heavy metals, 15 subterranean estuaries (STEs) along southwest Indian coast were sampled over three contrasting seasons. The average concentration of metals were ranked as, pre-monsoon > monsoon > post-monsoon with 3 to 12-fold higher groundwater metal concentrations than the adjacent seawater. Average SGD derived essential metal fluxes were five times higher than the toxic metal fluxes of which Fe and Zn together contributed >90 %. Using the Single Factor Contamination Index, the majority of sites were minimally contaminated with only two sites indicating moderate ecological risk due to As. Higher fluxes of Fe, Cu and Zn were likely a result of rising anthropogenic activities. The SGD derived nutrient fluxes were an important source of DIP for primary production in coastal waters and represented 30 % and 44 % of the DIN and DIP inputs respectively.


Subject(s)
Groundwater , Metals, Heavy , Estuaries , Seasons , Seawater , Nutrients , India , Environmental Monitoring
11.
Data Brief ; 48: 109155, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37168601

ABSTRACT

Agriculture is the art and science of cultivating the soil, growing crops and raising livestock. Enhancing crop yield becomes essential to improve economy in agriculture sector. Crops need 16 essential nutrients in balanced factor for their proper growth. Deficiency among these essential nutrients causes stunted growth often leading to significant crop loss. Symptoms of nutrient deficiency in plants can be observed visually which needs to be diagnosed correctly to rectify the problem, so that plants can grow healthily, increasing its yield. Among various crops, banana is one of the staple foods for millions of people across country and world. They contain essential nutrients that can have a defending impact on health of the human beings. The year-round availability, affordability, varietal range, taste, nutritive of banana and medicinal value makes it the favorite fruit among all classes of people. In addition, it also has good export potential. Few of the symptoms due to nutrient's deficiency in banana leaves are like curling of leaves, appearance of yellow strips, yellowing of the leaves, bluish color of young leaves. Deficiency symptoms can be visualized prominently on the leaves of the plant. Further, Machine Learning models can be developed to detect nutrient deficiency in leaves and help farmers in taking relevant measures. Thus, a fully labelled dataset becomes essential to train and test these models to detect nutrient deficiency accurately. The dataset created consists of banana leaf images of various categories like Musa acuminata (Dwarf Cavendish), Robusta, Rasthali, Poovan, Monthan, Elakkibale. Images depict deficiency in eight class of nutrients: boron, calcium, iron, potassium, manganese, magnesium, sulphur and zinc. Table 1 summarizes the essential nutrients and their deficiency symptoms visible on the leaves. Dataset also contains images of healthy leaves. Machine Learning Models can be developed by researchers and students and train them by using the created banana dataset to obtain high accuracy.

12.
Sci Total Environ ; 887: 164105, 2023 Aug 20.
Article in English | MEDLINE | ID: mdl-37172851

ABSTRACT

Oxidative potential (OP) of fine marine aerosols (PM2.5) over the northern Indian Ocean (N_IO) and equatorial Indian Ocean (E_IO) were studied using shipborne measurements conducted as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018). During the study, an enhanced concentration of PM2.5 was found over N_IO (27.22 ± 14.29 µg.m-3) compared with E_IO (15.91 ± 2.58 µg.m-3), as N_IO experiences continental outflow from anthropogenically dominated South Asian region. However, E_IO received pristine air masses from the middle of the Arabian Sea, implying a reduced concentration. The OP of PM2.5 was evaluated using a dithiothreitol (DTT) assay. The mass (DTTm or intrinsic OP) and volume (DTTv or extrinsic OP) normalized DTT exhibited a significant spatial variation over the Indian Ocean (IO). Intrinsic OP showed ∼2 times higher values over N_IO than E_IO, indicating aging of aerosols during long-range transport impacts OP of marine aerosol. Similarly, increased concentrations of anthropogenic species such as non-sea sulfate (nssSO42-), nitrate (NO3-), ammonium (NH4+), non-sea potassium ion (nssK+), water-soluble transition metals (Fe, Ti, Zn, Cu, Mn, Cr), elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC), were also observed over N_IO compared with E_IO. Pearson correlation and multiple linear regression (MLR) analysis revealed that combustion sources, chemical processing and co-transportation of anthropogenic species during long-range transport are the main drivers of intrinsic OP in the outflow region.

13.
Sci Rep ; 13(1): 5356, 2023 Apr 01.
Article in English | MEDLINE | ID: mdl-37005427

ABSTRACT

This report scrutinized the influence of radiation and Ohmic heating on the dissipative flow of micropolar and hybrid nanofluid within an inclined length [Formula: see text] channel under convective boundary conditions. Primary flow equations are renewed as the system of NODEs with the assistance of proper similarity conversions. In two circumstances, hybrid fluid flow and micropolar fluid flow, a blend of shooting and Runge-Kutta 4th order strategy, is used to achieve the desired results. The critical consequences of the current study are Larger pressure gradient minimizes the fluid velocity, and a more significant inertia parameter minimizes the rotation profile in the case of Newtonian fluid flow but facilitates the same in the case of hybrid nanofluid flow. It is perceived that the escalation in Brinkmann number causes the amelioration in the fluid temperature, and the radiation parameter mitigates the same. Furthermore, it is discovered that the Grashoff number enhances the Bejan number at the centre of the channel but lessens the same at other areas. Finally, validation is executed to compare the current outcomes with the former results and perceive a good agreement.

14.
IET Nanobiotechnol ; 16(9): 295-304, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36200801

ABSTRACT

Human pluripotent stem cells (hPSCs) can be proliferated on completely synthetic materials under xeno-free cultivation conditions using biomaterials grafted with extracellular matrix protein (ECM)-derived peptides. However, cell culture biomaterials grafted with ECM-derived peptides must be prepared using a high concentration of peptide reaction solution (e.g. 1000 µg/ml), whereas the ECM concentration of the ECM-coated surface for hPSC culture is typically 5 µg/ml. We designed a polyethylene glycol (PEG) joint nanosegment (linker) to be used between base cell culture biomaterials and bioactive ECM-derived peptides to enhance the probability of contact between ECM-derived peptides and cell binding receptors of hPSCs. Vitronectin-derived peptides with glycine joint nanosegments (GCGG) were conjugated onto poly (vinyl alcohol-co-itaconic acid) hydrogels via PEG joint nanosegments, and human embryonic stem cells (hESCs) were cultivated on these hydrogels. hESCs could successfully be cultivated on hydrogels while maintaining their pluripotency and differentiation potential to differentiate into cells that are induced from three germ layers in vitro and in vivo, where only a 50 µg/ml ECM-derived peptide concentration was used when the PEG joint nanosegments were introduced into peptides that were grafted onto hydrogel surfaces. The joint nanosegments between bioactive peptides and base cell culture biomaterials were found to contribute to efficient hESC attachment and proliferation.


Subject(s)
Human Embryonic Stem Cells , Hydrogels , Humans , Polyethylene Glycols , Extracellular Matrix Proteins , Peptides/pharmacology , Polyvinyl Alcohol , Biocompatible Materials/pharmacology , Cells, Cultured
15.
Virusdisease ; 33(4): 429-444, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36311173

ABSTRACT

Background: Severe acute respiratory syndrome Coronavirus-2 invades the cells via ACE2 receptor and damages multiple organs of the human body. Understanding the pathological manifestation is mandatory to endure the rising post-infection sequel reported in patients with or without comorbidities. Materials and methods: Our descriptive review emphasises the direct, indirect and post-infection damages due to COVID-19. We have performed an electronic database search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with selective inclusion and exclusion criteria. Results: The included studies substantiated the extensive damages in the multiple organs due to direct and indirect consequences of COVID-19. After an apparent recovery, the prolonged presentation of the symptoms manifests as post-COVID that can be related with persisting viral antigens and dysregulated immune response. Conclusion: A few of the symptoms of respiratory, cardiovascular, and neuropsychiatric systems that persist or reappear as post-COVID manifestations. Vaccination and preventive programs will effectively reduce the prevalence but, the post-COVID, a multisystem manifestation, will be a significant tribulation to the medical profession. However, the issue can be managed by implementing public health programs, rehabilitation services, and telemedicine virtual supports to raise awareness and reduce panic.

16.
Nanomaterials (Basel) ; 12(14)2022 Jul 12.
Article in English | MEDLINE | ID: mdl-35889605

ABSTRACT

Squeezing flow is a flow where the material is squeezed out or disfigured within two parallel plates. Such flow is beneficial in various fields, for instance, in welding engineering and rheometry. The current study investigates the squeezing flow of a hybrid nanofluid (propylene glycol-water mixture combined with paraffin wax-sand) between two parallel plates with activation energy and entropy generation. The governing equations are converted into ordinary differential equations using appropriate similarity transformations. The shooting strategy (combined with Runge-Kutta fourth order method) is applied to solve these transformed equations. The results of the conducted parametric study are explained and revealed in graphs. This study uses a statistical tool (correlation coefficient) to illustrate the impact of the relevant parameters on the engineering parameters of interest, such as the surface friction factor at both plates. This study concludes that the squeezing number intensifies the velocity profiles, and the rotating parameter decreases the fluid velocity. In addition, the magnetic field, rotation parameter, and nanoparticle volumetric parameter have a strong negative relationship with the friction factor at the lower plate. Furthermore, heat source has a strong negative relationship with heat transfer rate near the lower plate, and a strong positive correlation with the same phenomena near the upper plate. In conclusion, the current study reveals that the entropy generation is increased with the Brinkman number and reduced with the squeezing parameter. Moreover, the results of the current study verify and show a decent agreement with the data from earlier published research outcomes.

17.
Sci Total Environ ; 845: 157163, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-35798104

ABSTRACT

Tropical coastal regions may provide a unique feature to study the photooxidation of various organic aerosols and their climatic effects because of high humid atmosphere and intense solar radiation. However, knowledge about organic molecular composition and its light absorption properties remains concealed, particularly over tropical Indian regions. The present study is an investigation on water-soluble dicarboxylic acids, ω-oxoacids, pyruvic acid, α-dicarbonyls, brown carbon (BrC), and other chemical species in PM1.1 collected at a coastal urban location (Kochi) on the west coast of tropical India under distinct air masses. Molecular distribution of dicarboxylic acids was characterized by the predominance of oxalic acid (C2) in all the air masses followed by adipic (C6) or terephthalic (tPh) and phthalic (Ph) acids. On average, total diacids-C accounted for 5.03 ± 1.01 % of TC. Total diacid concentration showed strong linear relationships with organic (OC), elemental carbon (EC), and non-sea-salt potassium (nss-K+). Except for the northwest (NW) air mass period, the concentration of C2 diacid and its ratios (C2/total diacids, C2/ωC2, C2/Gly) showed a strong linear relationship with nss-SO42-. By combining all these results together with Pearson correlation analysis, the present study demonstrates that organic aerosols over the study region were predominantly produced by aqueous-phase oxidation of precursor compounds derived from biomass burning and combustion-related emissions. The mass absorption coefficient of BrC (babs-BrC-365nm) was strongly correlated with nss-K+, implying that biomass burning emissions are major sources of BrC. The absorption angstrom exponent (AÅE) values of water (methanol) extracts ranged from 3.20 to 3.83 (3.05-4.55) during the entire sampling period, indicating the substantial contribution of BrC chromophores to light absorption over the region. On average, BrC absorbs 10.6 ± 6.4 % and 22.4 ± 5.75 % of solar radiation compared to BC in water and methanol extracts, respectively, suggesting that BrC is a significant aerosol climate forcing agent over the west coast of tropical India.


Subject(s)
Air Pollutants , Particulate Matter , Aerosols/analysis , Air Pollutants/analysis , Carbon/analysis , Dicarboxylic Acids , Environmental Monitoring/methods , Methanol , Particulate Matter/analysis , Water/chemistry
18.
Sci Rep ; 12(1): 11307, 2022 Jul 04.
Article in English | MEDLINE | ID: mdl-35789186

ABSTRACT

The convection, thermal conductivity, and heat transfer of hybrid nanofluid through nanoparticles has become integral part of several natural and industrial processes. In this manuscript, a new fractionalized model based on hybrid nanofluid is proposed and investigated by employing singular verses and non-singular kernels. The mathematical modeling of hybrid nanofluid is handled via modern fractional definitions of differentiations. The combined Laplace and Fourier Sine transforms have been configurated on the governing equations of hybrid nanofluid. The analytical expression of the governing temperature and velocity equations of hybrid nanofluid have been solved via special functions. For the sake of thermal performance, dimensional analysis of governing equations and suitable boundary conditions based on Mittage-Leffler function have been invoked for the first time in literature. The comparative analysis of heat transfer from hybrid nanofluid has been observed through Caputo-Fabrizio and Atangana-Baleanu differential operators. Finally, our results suggest that volume fraction has the decelerated and accelerated trends of temperature distribution and inclined and declined profile of heat transfer is observed copper and alumina nanoparticles.

19.
20.
Sci Rep ; 12(1): 7761, 2022 05 11.
Article in English | MEDLINE | ID: mdl-35545631

ABSTRACT

The dust plume tracks from the Middle East and Eastern Africa to the Indian subcontinent have an impact on the atmospheric and ocean biogeochemistry of the Arabian Sea (AS). Here, we present the impact of dust on net primary productivity (NPP) over the AS using satellite-based observation and model simulation. Seasonal episodes and long-term trends in dust optical depth (DOD), dust mass flux (DMF) and dust deposition flux (DDF) from 2007 to 2020 are quantified. Nearly 32% of the total dust is advected to the AS during transport (maximum in JJA; DMF ~ 33.1 Tg year-1 ~ 56% of annual and DDF ~ 5.5 Tg year-1 ~ 63% of annual). Over the last one and half decades, there has been a statistically significant decreasing trend in DOD, associated with precipitation, enhanced vegetation index and surface soil moisture over the landmasses in the proximity of the AS. Similarly, the depletion in DDF suppresses the NPP over different regions of the AS, especially over the central AS, where the oceanic supply of nutrients is limited.


Subject(s)
Dust , Minerals , Africa, Eastern , Dust/analysis , Middle East , Oceans and Seas
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