Showing papers by "Prashant Kumar published in 2017"

Microalgae: An emerging source of energy based bio-products and a solution for environmental issues

Abstract: The microalgae biomass is emerging as a potential source of energy and bioproducts with several advantages over conventional crops in terms of its ability to produce ~300-times more renewable oil. Microalgae also have a high photosynthetic response, product accumulation rate and biomass production rate compared with other energy crops. Microalgae have the ability to grow on nonagricultural soil using wastewater instead of drinking water. Furthermore, microalgae have high capability to fix carbon dioxide from the environment. Microalgae-based bioproducts have different applications in pharmaceuticals, food and feed industries, and agricultural and transportation sectors. The key objectives covered in this review pertain to the role of microalgae to (i) maintain food chain, (ii) conservation of land and water resources in the environment with sequestration of CO2, (iii) production of energy in the form of biodiesel with zero waste, and (iv) simultaneous release of higher oxygen to the environment compared with other energy crops.

Insight into partial agonism by observing multiple equilibria for ligand-bound and Gs-mimetic nanobody-bound β1-adrenergic receptor

Abstract: A complex conformational energy landscape determines G-protein-coupled receptor (GPCR) signalling via intracellular binding partners (IBPs), e.g., Gs and β-arrestin. Using 13C methyl methionine NMR for the β1-adrenergic receptor, we identify ligand efficacy-dependent equilibria between an inactive and pre-active state and, in complex with Gs-mimetic nanobody, between more and less active ternary complexes. Formation of a basal activity complex through ligand-free nanobody–receptor interaction reveals structural differences on the cytoplasmic receptor side compared to the full agonist-bound nanobody-coupled form, suggesting that ligand-induced variations in G-protein interaction underpin partial agonism. Significant differences in receptor dynamics are observed ranging from rigid nanobody-coupled states to extensive μs-to-ms timescale dynamics when bound to a full agonist. We suggest that the mobility of the full agonist-bound form primes the GPCR to couple to IBPs. On formation of the ternary complex, ligand efficacy determines the quality of the interaction between the rigidified receptor and an IBP and consequently the signalling level. β1-adrenergic receptors are expressed in cardiac tissue and stimulated by the sympathetic nervous system. Here, the authors use NMR spectroscopy to unravel the conformational diversity upon β1-adrenergic receptor activation and provide structural insights into partial agonism and basal activity.

Particulate pollutants in the Brazilian city of São Paulo: 1-year investigation for the chemical composition and source apportionment

Abstract: . Sao Paulo in Brazil has relatively relaxed regulations for ambient air pollution standards and often experiences high air pollution levels due to emissions of particulate pollutants from local sources and long-range transport of air masses impacted by biomass burning. In order to evaluate the sources of particulate air pollution and related health risks, a year-round sampling was done at the University of Sao Paulo campus (20 m a.g.l.), a green area near an important expressway. The sampling was performed for PM2. 5 ( ≤ 2. 5 µm) and PM10 ( ≤ 10 µm) in 2014 through intensive (everyday sampling in wintertime) and extensive campaigns (once a week for the whole year) with 24 h of sampling. This year was characterized by having lower average precipitation compared to meteorological data, and high-pollution episodes were observed all year round, with a significant increase in pollution level in the intensive campaign, which was performed during wintertime. Different chemical constituents, such as carbonaceous species, polycyclic aromatic hydrocarbons (PAHs) and derivatives, water-soluble ions, and biomass burning tracers were identified in order to evaluate health risks and to apportion sources. The species such as PAHs, inorganic and organic ions, and monosaccharides were determined using chromatographic techniques and carbonaceous species using thermal-optical analysis. Trace elements were determined using inductively coupled plasma mass spectrometry. The risks associated with particulate matter exposure based on PAH concentrations were also assessed, along with indexes such as the benzo[a]pyrene equivalent (BaPE) and lung cancer risk (LCR). High BaPE and LCR were observed in most of the samples, rising to critical values in the wintertime. Also, biomass burning tracers and PAHs were higher in this season, while secondarily formed ions presented low variation throughout the year. Meanwhile, vehicular tracer species were also higher in the intensive campaign, suggesting the influence of lower dispersion conditions in that period. Source apportionment was performed using positive matrix factorization (PMF), which indicated five different factors: road dust, industrial emissions, vehicular exhaust, biomass burning and secondary processes. The results highlighted the contribution of vehicular emissions and the significant input from biomass combustion in wintertime, suggesting that most of the particulate matter is due to local sources, in addition to the influence of pre-harvest sugarcane burning.

A review of emissions and concentrations of particulate matter in the three major metropolitan areas of Brazil

Abstract: Highlights - Emissions and concentrations in three Brazilian metropolitan areas are reviewed. - In 2014, vehicular emissions contributed 34% of the total Brazilian PM2.5 emissions. - Non-exhaust sources could represent 90% of the Brazilian PM emissions from 2020 onwards. - Brazilian cities have relatively relaxed guidelines of PM concentration compared with WHO. - Studied metropolitan areas showed up to 3-fold high concentrations above WHO guidelines. Abstract We critically assessed numerous aspects such as vehicle fleet, type of fuel used in road vehicles, their emissions and concentrations of particulate matter ≤2.5 µm (PM2.5) and ≤10 µm (PM10) in three of the most polluted metropolitan areas of Brazil: the Metropolitan areas of Sao Paulo (MASP), Rio de Janeiro (MARJ) and Belo Horizonte (MABH). About 90% of the Brazilian LDVs run on ethanol or gasohol. The HDVs form a relatively low fraction of the total fleet but account for 90% of the PM from road vehicles. Brazilian LDVs normally emit 0.0011 g (PM) km−1 but HDVs can surpass 0.0120 g (PM) km−1. The emission control programs (e.g., PROCONVE) have been successful in reducing the vehicular exhaust emissions, but the non-exhaust vehicular sources such as evaporative losses during refueling of vehicles as well as wear from the tyre, break, and road surface have increased in line with the increase in the vehicle fleet. The national inventories show the highest annual mean PM2.5 (28.1 μg m−3) in the MASP that has the largest vehicle fleet in the country. In general, the PM10 concentrations in the studied metropolitan areas appear to comply with the national regulations but were up to ~3-times above the WHO guidelines. The current Brazilian air quality standards are far behind the European standards. There has been a progress in bringing more restrictive regulations for air pollutants including PM10 and PM2.5 but such steps also require suitable solutions to control PM emissions from motor vehicles and mechanical processes.

Characterization of five-year observation data of fine particulate matter in the metropolitan area of Lahore.

Abstract: This study aims to assess the long-term trend of fine particles (PM2.5; ≤2.5 μm) at two urban sites of Lahore during 2007-2011. These sites represent two distinct areas: commercial (Townhall) and residential cum industrial (Township). The highest daily mean concentrations of PM2.5 were noted as 389 μg m–3 and 354 μg m–3 at the Townhall and Township sites, respectively. As expected, the annual seasonal mean of PM2.5 was about 53% and 101% higher during winter compared with the summer and monsoon/post-monsoon seasons, respectively. On contrary to many observations seen in developing cities, the annual mean PM2.5 during the weekends was higher than weekdays at both monitoring sites. For example, these were 100 (142) μg m–3 and 142 (148) μg m–3 during the weekdays (weekends) at the Townhall and Township sites, respectively. The regression analysis showed a significant positive correlation of PM2.5 with SO2, NO2, and CO as opposed to a negative correlation with O3. The bivariate polar plots suggested a much higher influence of localised sources (e.g., road vehicles) at the Townhall site as opposed to industrial sources affecting the concentrations at the Township site. The imageries from the MODIS Aqua/Terra indicated long-range transport of PM2.5 from India to Pakistan during February to October whereas from Pakistan to India during November to January. This study provides important results in the form of multi-scale relationship of PM2.5 with its sources and precursors, which are important to assess the effectiveness of pollution control mitigation strategies in Lahore and similar cities elsewhere.

Multi-criteria evaluation of hydro-geological and anthropogenic parameters for the groundwater vulnerability assessment

Abstract: Groundwater contamination assessment is a challenging task due to inherent complex dynamisms associated with the groundwater. DRASTIC is a very widely used rapid regional tool for the assessment of vulnerability of groundwater to contamination. DRASTIC has many lacunas in the form of subjectivities associated with weights and ratings of its hydro-geological parameters, and, therefore, the accuracy of the DRASTIC-based vulnerability map is questioned. The present study demonstrates the optimisation of the DRASTIC parameters along with a scientific consideration to the anthropogenic factors causing groundwater contamination. The resulting scientific consistent weights and ratings to DRASTIC parameters assist in the development of a very precise groundwater vulnerability map highlighting different zones of different gravity of contamination. One of the most important aspects of this study is that we have considered the impact of vadose zone in a very comprehensive manner by considering every sub-surface layer from the earth surface to the occurrence of groundwater. The study area for our experiment is Fatehgarh Sahib district of Punjab which is facing several groundwater issues.

Classification of heavy metal ions present in multi-frequency multi-electrode potable water data using evolutionary algorithm

Abstract: Access to potable water for the common people is one of the most challenging tasks in the present era. Contamination of drinking water has become a serious problem due to various anthropogenic and geogenic events. The paper demonstrates the application of evolutionary algorithms, viz., particle swan optimization and genetic algorithm to 24 water samples containing eight different heavy metal ions (Cd, Cu, Co, Pb, Zn, Ar, Cr and Ni) for the optimal estimation of electrode and frequency to classify the heavy metal ions. The work has been carried out on multi-variate data, viz., single electrode multi-frequency, single frequency multi-electrode and multi-frequency multi-electrode water samples. The electrodes used are platinum, gold, silver nanoparticles and glassy carbon electrodes. Various hazardous metal ions present in the water samples have been optimally classified and validated by the application of Davis Bouldin index. Such studies are useful in the segregation of hazardous heavy metal ions found in water resources, thereby quantifying the degree of water quality.

Source apportionment of BTEX compounds in Tehran, Iran using UNMIX receptor model

Abstract: Understanding the distribution levels and sources of volatile organic compounds (VOC), mainly benzene, toluene, ethylbenzene and xylenes (BTEX), in the ambient atmosphere is important for efficiently managing and implementing the associated control strategies. We measured BTEX compounds at an industrial location in the west Tehran city (Iran), which is highly influenced by industrial activities and traffic during the winter and spring seasons during 2014-2015. A multivariate receptor model, UNMIX, was applied on the measured data for the identification of the sources and their contributions to BTEX compounds in a highly industrialised and trafficked atmospheric environment of Tehran city. Three main groups of sources were identified. These included solvent and painting sources (e.g. vehicle manufacturing), motorised road vehicles and mixed origin sources. While the solvent and painting sources and vehicle exhaust emissions contributed to about 5 and 29% of total BTEX mass, respectively, the mixed origin source contributed to about two-third (~66%) of the remaining mass. These mixed origin sources included rubber and plastic manufacturing (39%), leather industries (28%) and the unknown sources (33%). The mean concentrations of benzene, toluene, ethylbenzene and average xylene(o, p,m) compounds were measured as 28.96±9.12 µg m –3 , 29.55±9.73 µg m –3 , 28.61±12.2 µg/m-3 and 25.68±10.58 µg m–3 , respectively. A high correlation coefficient (R 2 >0.94) was also found between predicted (modelled) and measured concentrations for each sample. Further analyses from UNMIX receptor model showed that the average weekday contributions of BTEX compounds were significantly higher during winter compared with those during spring. This higher concentration during winter may be attributed to calm wind conditions and high stability of the atmosphere, along with the after effect of government policies on the use of cleaner fuel in refineries that became operational in winter 2014

Effect of disorder on superconductivity and Rashba spin-orbit coupling in LaAlO3/SrTiO3 interfaces

Abstract: A rather unique feature of the two-dimensional electron gas formed at the interface between the two insulators LaAlO3 and SrTiO3 is to host both gate-tunable superconductivity and strong spin-orbit coupling. In the present work, we use the disorder generated by Cr substitution of Al atoms in LaAlO3 as a tool to explore the nature of superconductivity and spin-orbit coupling in these interfaces. We analyze the transport properties of three different samples whose only relevant difference is their elastic scattering time tau(e). A reduction of the superconducting T-c is observed with Cr doping consistent with an increase of electron-electron interaction in the presence of disorder. In addition, the evolution of spin-orbit coupling with gate voltage and Cr doping evidences a Dyakonov-Perel mechanism of spin relaxation (tau(SO) proportional to tau(-1)(e)) in the presence of a Rashba-type spin-orbit interaction.

Assessing the Suitability of Multiple Dispersion and Land Use Regression Models for Urban Traffic-Related Ultrafine Particles

Abstract: Comparative evaluations are needed to assess the suitability of near-road air pollution models for traffic-related ultrafine particle number concentration (PNC). Our goal was to evaluate the ability of dispersion (CALINE4, AERMOD, R-LINE, and QUIC) and regression models to predict PNC in a residential neighborhood (Somerville) and an urban center (Chinatown) near highways in and near Boston, Massachusetts. PNC was measured in each area, and models were compared to each other and measurements for hot (>18 °C) and cold (<10 °C) hours with wind directions parallel to and perpendicular downwind from highways. In Somerville, correlation and error statistics were typically acceptable, and all models predicted concentration gradients extending ∼100 m from the highway. In contrast, in Chinatown, PNC trends differed among models, and predictions were poorly correlated with measurements likely due to effects of street canyons and nonhighway particle sources. Our results demonstrate the importance of selecting PNC m...

Evaluation of formaldehyde concentration in the ambient air of a most populated Iranian city, Tehran

Abstract: Exposure to high levels of formaldehyde is known as both acute and chronic health problems, but the studies analyzing ambient concentrations of formaldehyde, especially in Middle East cities such as Tehran, are still rare. The aim of this study is to survey the variations in the concentration of formaldehyde in several areas with a high traffic volume of Tehran city during different seasons. The other objectives include understanding the influence of carbon monoxide, ozone and nitrogen dioxide concentrations, ambient temperature, relative humidity, and air pressure on the variation of formaldehyde concentration. Measurements were carried out during the period of 6 months between 2013 (December 22 to February 14) and 2014 (April 27 to June 20 at five different locations within the city, together with a background site. One hundred and eight samples, each averaged over 3 hours from 11 AM to 2PM, were taken from the sampling locations. The average concentration of formaldehyde in the spring (22.7±5.3 ppb) was found about 1.31 times higher than winter (17.3±4.2ppb). Formaldehyde concentrations demonstrated a significant correlation with the changes in air temperature (in the range of 0.46 to 0.66 for different locations) but not having any strong correlation with humidity and pressure. Carbon monoxide and nitrogen dioxide showed a significant coefficient of determination with formaldehyde concentrations with R2 as 0.80 and 0.67 during the winter, respectively, whereas the corresponding R2 values during spring were 0.39 and 0.41. Ozone showed a significant correlation with formaldehyde (R2=0.64) during the spring and has not such the significant correlation during the season winter (R2=0.23). Overall, it concluded that Road vehicles were recognized as main contributor of formaldehyde production during both the seasons, especially in the winter, also photochemical oxidation was another important and considerable contributor producing formaldehyde during the spring.

Determinants of respiratory and cardiovascular health effects in traffic policemen: A perception-based comparative analysis

Abstract: This study investigates the determining factors behind the adverse health effects of traffic policemen in National Capital Territory (NCT) of Delhi. A comparative analysis between 532 traffic policemen (subject population) and 150 office workers (control group) was undertaken to study the prevalence of disease. A primary survey was conducted over a period of six months between July 2015 and February 2016 using a questionnaire survey as a primary tool. A significantly higher (p = 0.005) prevalence rate of respiratory and cardiovascular diseases was observed among traffic policemen compared with the control group. Symptoms such as thick sputum, pain in joints, and shortness of breath were prevalent in approximately 59%, 56%, and 45% of subjects, as compared to about 15%, 11% and 6% of the control population. The relative risk of developing respiratory and cardiovascular diseases was found to be significantly higher (RR>1) for the traffic policemen in comparison to the office workers (control group). This is a first cross-sectional study to highlight the plight of traffic policemen in the NCT region of Delhi. The influence of factors such as Body Mass Index (BMI), age, habits (smoking and alcohol consumption) and service duration on disease prevalence was assessed among traffic policemen using statistical tests. The service duration was found to be the most important determinant compared with other influencing factors such as BMI, age, which is significantly (p = 0.02) affecting the health of traffic policemen in the current study. A number of potential measures for improving the health conditions of traffic policemen are also discussed.

Chronic Exposure to Cigarette Smoke and Chewing Tobacco Alters Expression of microRNAs in Esophageal Epithelial Cells.

Abstract: BACKGROUND Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers with high mortality rate. Cigarette smoke and chewing tobacco are well known risk factors associated with ESCC. However, molecular mechanisms associated with development of ESCC among smokers and chewers are poorly understood. MicroRNAs play an important role in regulating physiological and disease processes including esophageal cancer. OBJECTIVE AND METHODS In this study, we developed an in vitro model by treating non-neoplastic Het- 1A esophageal cell line with cigarette smoke and chewing tobacco. We carried out miRNA sequencing on Illumina HiSeq 2500 platform and compared miRNA expression pattern across cigarette smoke and chewing tobacco treated Het-1A cells with untreated cells. RESULTS We identified and quantified 433 miRNAs in both smoke exposed and chewing tobacco treated cells, of which 13 miRNAs showed significantly altered expression in cigarette smoke exposed cells while 25 miRNAs showed significantly altered expression in chewing tobacco treated cells. In addition, we predicted novel miRNAs from these data-sets. We evaluated miRNAs that showed selective or context dependent expression pattern in cigarette smoke exposed or chewing tobacco treated cells. CONCLUSION In this study, we have comprehensively mapped miRNA expression pattern in response to cigarette smoke and chewing tobacco in Het-1A cells. We identified miRNAs that show altered expression in these cell models.

Evaluation of coarse and fine particles in diverse Indian environments

Abstract: The estimates of airborne fine particles (PM2.5) concentrations are possible through rigorous empirical correlations based on the monitored PM10 data. However, such correlations change depending on the nature of sources in diverse ambient environments and, therefore, have to be environment specific. Studies presenting such correlations are limited but needed, especially for those areas, where PM2.5 is not routinely monitored. Moreover, there are a number of studies focusing on urban environments but very limited for coal mines and coastal areas. The aim of this study is to comprehensively analyze the concentrations of both PM10 and PM2.5 and develop empirical correlations between them. Data from 26 different sites spread over three distinct environments, which are a relatively clean coastal area, two coal mining areas, and a highly urbanized area in Delhi were used for the study. Distributions of PM in the 0.43-10 μm size range were measured using eight stage cascade impactors. Regression analysis was used to estimate the percentage of PM2.5 in PM10 across distinct environments for source identification. Relatively low percentage of PM2.5 concentrations (21, 28 and 32 %) in PM10 were found in clean coastal and two mining areas respectively. Percentage of PM2.5 concentrations in PM10 in the highly urbanized area of Delhi was 51%, indicating a presence of a much higher percentage of fine particles due to vehicular combustion in Delhi. The findings of this work is important in estimating concentrations of much harmful fine particles from coarse particles across distinct environments. The results are also useful in source identification of particulates as differences in the percentage of PM2.5 concentrations in PM10 can be attributed to characteristics of sources in the diverse ambient environments.

Airborne particles in the Brazilian city of São Paulo: One-year investigation for the chemical composition and source apportionment

Abstract: Sao Paulo in Brazil has relatively relaxed regulations for ambient air pollution standards and often experiences high air pollution levels due to emissions of airborne particles from local sources and long-range transport of biomass burning-impacted air masses. In order to evaluate the sources of particulate air pollution (PM) and related health risks, a year-round sampling was performed for PM 2.5 (l 2.5 μm) and PM 10 (l 10 μm) in 2014 through intensive (every day sampling in wintertime) and extensive campaigns (once a week for the whole year) with 24 h of sampling. This year was characterized to have lower average precipitation comparing to meteorological data, and high pollution episodes were observed all year round, with a significant increase of pollution level in the intensive campaign, which was performed during wintertime. Different chemical constituents, such as carbonaceous species, polycyclic aromatic hydrocarbons (PAHs) and derivatives, water-soluble ions and biomass burning tracers were identified in order to evaluate health risks and to apportion sources. The species such as PAHs, inorganic and organic ions and monosaccharides were determined by chromatographic techniques and carbonaceous species by thermal-optical analysis. The associated risks to particulate matter exposure based on PAH concentrations were also assessed, along with indexes such as the benzo[a]pyrene equivalent (BaPE) and lung cancer risk (LCR). High BaPE and LCR were observed in most of the samples, rising to critical values in the wintertime. Also, biomass burning tracers and PAHs were higher in this season, while secondarily formed ions presented low variation throughout the year. Meanwhile, vehicular tracer species were also higher in the intensive campaign suggesting the influence of lower dispersion conditions in that period. Source apportionment was done by Positive Matrix Factorization (PMF), which indicated five different factors: road dust, industrial emissions, vehicular exhaust, biomass burning and secondary processes. The results highlighted the contribution of vehicular emissions and the significant input from biomass combustion in wintertime, suggesting that most of the particulate matter is due to local sources, besides the influence of pre-harvest sugarcane burning.

Ankyloglossia in Infancy: An Indian Experience.

Abstract: To study the prevalence, clinical presentation and management of infants with ankyloglossia. A retrospective file review of infants less than 6 months of age with a diagnosis of ankyloglossia. Of the 25786 babies born during the assessment period (2007-2015), 134 (0.52%) had ankyloglossia. Sixty-four (47.7%) infants who presented with breastfeeding difficulties were diagnosed significantly earlier than the asymptomatic group (P<0.05). Of the symptomatic group, 85.9% underwent frenotomy with satisfactory results. Seventy asymptomatic infants were managed conservatively with counselling. Frenotomy seems to be a safe and effective procedure in infants with symptomatic ankyloglossia.

Environmental Effect of Climate Change Pollutants Loading on Structural Steel Stresses

Abstract: Human activities on earth it is observed is having negative impact on the continuous existence of life on the planet. This is as a result of build-up of gases that tend to affect life and well-being of plants and animals including structures put in place to support them. Structural failure as a result of pollutant exposure does not occur unless where there is wrong design of the structure or the owner has not carried out routine maintenance. The effect of such loss on structure in place need to be further studied to engender better understanding of structural failure possibilities or its reliability. This work looked at the effect of gases such as SO2 and humidity known as climate change gases in the air and their effect on steel structures, specifically bridges, in rural, urban and industrial locations. It was shown also that for these three types of locations, the moment resistance and shear resistance of structures overtime will decrease by 3% and 4.6% respectively. However, the deflection of the same structure will increase by 1% over the same time range. The implication will be an increase in the cost of design and construction as a result of increased thickness of steel structures and additional paint coating to reduce this negative effect

An Overview of Monitoring and Reduction Strategies for Health and Climate Change Related Emissions in the Middle East and North Africa Region Atmospheric Environment

Abstract: This review assesses the current state of air pollution in the Middle East and North Africa (MENA) region. Emission types and sources in the region are identified and quantified to understand the monitoring, legislative and reduction need through a systematic review of available literature. It is found that both health (e.g., particulate matter, PM, and heavy metals) and climate change (e.g., carbon dioxide and methane) emissions are increasing with the time. Regarding health emissions, over 99% of the MENA population is exposed to PM levels that exceed the standards set by the World Health Organization (WHO). The dominant source of climate change emissions is the energy sector contributing ~38% of CO2 emissions, followed by the transport sector at ~25%. Numerous studies have been carried out on air pollution in the region, however, there is a lack of comprehensive regional studies that would provide a holistic assessment. Most countries have air quality monitoring systems in place, however, the data is not effectively evaluated to devise pollution reduction strategies. Moreover, comprehensive emission inventories for the individual countries in the region are also lacking. The legislative and regulatory systems in MENA region follow the standards set by international environmental entities such as the WHO and the U.S. Environmental Protection Agency but their effective reinforcement remains a concern. It is concluded that the opportunities for emission reduction and control could be best implemented in the road transportation sector using innovative technologies. One of the potential ways forward is to channel finance flows from fossil fuel subsidies to upgrade road transport with public transportation systems such as buses and trains, as suggested by a ‘high shift’ scenario for MENA region. Furthermore, emission control programs and technologies are more effective when sponsored and implemented by the private sector; the success of Saudi Aramco in supporting national emission monitoring is onesuch example. Finally, an energy-pollution-water nexus is assessed for the region as an integrated approach to address urban issues. The assessment of topic areas covered clearly suggest a need to control the main sources of air pollution to limit its relatively high impact on the human health in the MENA region.