Volatile Organic Hydrocarbons Research Articles

Water-bridged self-assembly of low-odor xanthate surfactant for selective flotation of chalcopyrite

Xanthate, a high-consumption functional surfactant, poses health and environmental risks due to the presence of volatile sulfides and pungent odors. In this study, we designed a novel ether group enhanced xanthate collector, O-(2-(tert-butoxy)ethyl) xanthate (TBOEX), which exhibits low odor and excellent flotation performance. The high matching between the calculated and the experimental infrared spectrum confirms the existence of water-bridged self-assembly behaviour. Odor evaluation results show that TBOEX reduced the content of volatile sulfur organic compounds and volatile hydrocarbons by 54.2% and 88.6%, respectively, compared to isobutyl xanthate (IBX), effectively reducing odor production. Flotation experiments and Zeta potential measurements demonstrate that TBOEX adsorbs densely on the surface of chalcopyrite, while the rich hydroxide on the surface of pyrite hinders the self-assembly of the collector, resulting in good selectivity for chalcopyrite. DFT calculations further reveal that TBOEX can form a stable and tightly arranged adsorption layer bridged by water molecules on the surface of chalcopyrite through two paths, and interact with d orbitals of copper atoms in the form of Cu-S tetrahedra through π* orbitals, finally improving the flotation recovery of chalcopyrite. The discovery of the water-bridge self-assembly mechanism and interfacial adsorption behavior of TBOEX is expected to drive the targeted design of collectors.

Air quality trends for the ports of Los Angeles and Long Beach spanning the covid19 crisis: Part 1. Oxidant pollutants

Ports are major air pollution sources impacting downwind communities with emissions from port activities, nearby energy and other heavy industries, truck, train, and vessel traffic, and commuting traffic. The Ports of Los Angeles/Long Beach, denoted Ports, are the western hemisphere's largest, with plans for port electrification to reduce air pollution. The covid19 shutdown impacted the Ports, providing a real-world experiment on the effects of electrification on exposure to neighboring communities.Eight in situ surveys with a mobile air quality laboratory (14 trace gases, aerosols, and meteorology) were conducted spanning the covid19 shutdown to characterize the resultant air quality changes. These data were combed with time series (2015-) from six Port area air quality stations and TROPOMI satellite nitrogen dioxide NO2 column XNO2.In situ surveys showed dramatic NO2 decreases from Jul. 2019 to May 2020 (during the shutdown), with NO2 only returning towards pre-covid levels by Jul. 2022. Lesser covid19 NO2 decreases were observed by the air quality station data and satellite XNO2 for the Los Angeles Basin; both showed NO2 decrease during the shutdown and an extended time for recovery to more normal concentration (and underlying economic activity) - until 2022 - far longer than the shutdown. Overall, ozone, O3 increased, signifying that O3, formation is volatile organic hydrocarbons, VOH, limited, with the strongest O3 source(s) arriving from offshore. This finding suggests efforts to purely address air quality by electrification without addressing area VOH emissions could potentially lessen, perhaps significantly, the expected air quality and health improvements in downwind communities. The Ports’ area industrial sites were identified as driving these VOHs, as the inverse relationship between NO2 and O3 persisted during the shutdown when non-industrial VOH sources would have decreased.

A critical review on phytoremediation of environmental contaminants in aquatic ecosystem

The rapid urbanization and economic development have resulted in an unprecedented pollution of the entire biosphere. Aquatic ecosystems have become a sink for the discharge of numerous pollutants ranging from nutrients, heavy metals, volatile organic compounds, hydrocarbons, pesticides, medicines, pathogens, and explosives. The accumulation of these pollutants poses a serious threat to aquatic biodiversity, and drinking contaminated water poses severe health hazards in humans. Phytoremediation, an eco-accommodating process, aids in the maintenance of aquatic ecosystem functionality by detoxifying, decomposing, converting, or chelating contaminants, allowing for the proper treatment of wastewater-contaminated water bodies. The development of phytoremediation technology was facilitated by the economic aspects and side effects of conventional treatment technologies. Nevertheless, constructed wetlands have acquired popularity among the numerous accessible methods for treating and recycling diverse wastewaters because they fulfill the criteria of sustainability, public health maintenance, esthetic balance, design intricacy, and cost. The prolonged-release of untreated industrial waste, domestic sewage, accidental spills, rainfall run-off, and direct solid waste disposal all have a substantial influence on aquatic environments. Both live and dead macrophyte biomass may be utilized in phytoremediation; however, dead biomass is typically favored for treating industrial effluents due to lower cost, ease of disposal, and lack of active biochemical machinery that causes metal toxicity and plant death. Some of the barriers to translating phytoremediation technology from the lab to the field include the issue of disposing of biomass and the seasonal growth of aquatic macrophytes. Yet, via numerous works, an eco-sustainable model has been created that could mitigate some of the restrictions. Macrophyte waste biomass has a wide range of productive uses. Future potential for the utilization of macrophytes in phytoremediation investigations includes genetic engineering, biodiversity exploration, and X-ray diffraction spectroscopy. This emerging technology may advance environmental science and technology using a multidisciplinary and integrated approach. This review, thus focuses on the various contaminants found in aquatic ecosystems, their treatment by various phytoremediation processes, some successful phytoremediation studies conducted so far for remediation purposes, and myriad types of constructed wetlands utilized for attenuating pollution levels in various types of wastewaters to bring them down to permissible levels.

Health consequences of exposure to aircraft contaminated air and fume events: a narrative review and medical protocol for the investigation of exposed aircrew and passengers

Thermally degraded engine oil and hydraulic fluid fumes contaminating aircraft cabin air conditioning systems have been well documented since the 1950s. Whilst organophosphates have been the main subject of interest, oil and hydraulic fumes in the air supply also contain ultrafine particles, numerous volatile organic hydrocarbons and thermally degraded products. We review the literature on the effects of fume events on aircrew health. Inhalation of these potentially toxic fumes is increasingly recognised to cause acute and long-term neurological, respiratory, cardiological and other symptoms. Cumulative exposure to regular small doses of toxic fumes is potentially damaging to health and may be exacerbated by a single higher-level exposure. Assessment is complex because of the limitations of considering the toxicity of individual substances in complex heated mixtures.There is a need for a systematic and consistent approach to diagnosis and treatment of persons who have been exposed to toxic fumes in aircraft cabins. The medical protocol presented in this paper has been written by internationally recognised experts and presents a consensus approach to the recognition, investigation and management of persons suffering from the toxic effects of inhaling thermally degraded engine oil and other fluids contaminating the air conditioning systems in aircraft, and includes actions and investigations for in-flight, immediately post-flight and late subsequent follow up.

Sustainable thinking toward to industry's future combined with new knowledge on greenhouse effect mitigation generated by the grinding process

Grinding is a machining process applied in the manufacture of components that require an excellent surface finish and high geometric and dimensional precision, being applied in the final stages of component manufacturing. Due to its high heat generation, grinding needs adequate lubrication and cooling methods, aiming to meet the demands of the ground component as well as to mitigate the environmental impacts resulting from the application of cutting fluids. Allied with this, the growing demand for new materials, such as advanced ceramics, has become a new challenge for grinding. In addition to being chemically and thermally stable, advanced ceramics are highly resistant to wear, making grinding this type of material difficult. Traditionally, cutting fluids have alkanolamines, nitrosamines, volatile organic compounds, mineral oils, hydrocarbons and heavy metals in their composition. Thus requiring proper disposal to inhibit groundwater and soil contamination, reducing immediate and long-term damage to the planet and society. That said, it is extremely important that scientific and technological advances in machining processes, especially grinding, allow for cleaner machining through techniques that reduce the need to apply large volumes of cutting fluid. In this sense, the minimum quantity lubrication technique (MQL) consists of applying a small amount of oil through a jet of compressed air, achieving results similar to the flood method in many cases. However, the lower cooling capacity of MQL is an obstacle to overcome. Thus, this work analyzed advanced grinding ceramics using a diamond grinding wheel combined with a new technology responsible for cleaning the grinding wheel (WCJ) under four different angles (0°, 30°, 60° and 90°). Surface roughness, roundness error, diametral wear of the grinding wheel, G ratio, grinding power, grinding cost analysis, and pollutant CO2 emissions involving each application were evaluated. As a result, the flood lubri-refrigeration method showed the best performance in roughness and surface roundness error values. However, the MQL + WCJ 30° presented similar results about the flooding method, proving competitive for industrial use. Furthermore, MQL applications led to lower CO2 pollution values than the flood method, making it a great green alternative for the environment.

SMOG AND HEALTH

Smog is a declared threatening Public Health Emergency in South Asia recently. The most affected areas are Pakistan, India, and China.1 Pakistan is today the world's fourth most polluted country due to industrial and vehicular emissions, crop burning, and recent projects of coal as a source of energy. The air pollution level in our region is getting alarming and is considered to be among the unhealthiest worldwide.2
 Most of the smog we see is "Photochemical Smog" containing volatile organic compounds, hydrocarbons, nitrogen, and sulfur dioxide. When the sunlight reacts with the nitrogen oxides and volatile organic compounds in the atmosphere, there is the production of airborne particles and smog. The problem is becoming serious over the last decade due to high levels of pollution due to vehicular smoke and industrial activities.3 Even now during the months of summer, there is now photochemical smog which is washed away by rain. Prolonged heavy exposure to hazardous air causes various health problems including asthma, bronchitis, lung cancer, skin cancer etc. 4
 A study reporting the long-term effects of smog in the great London concluded that exposure to smog during the first year of life increased the risk of childhood asthma by 19.87%. 5
 Pollution and winter weather conditions both shroud the cities in smog. Excessive population, shortage of funds for development especially municipal services, illiteracy, poverty, vehicular emissions, industrial pollution, fossil fuel powered plants, burning of trees for industrial development, burning of waste materials and coal being burned by thousands of brick kilns all contribute to the formation of smog.6
 Certain Measures should be taken to control this alarming health hazard. Effective legislation, effective public awareness programs are needed via print and electronic media. Use of face masks particularly outdoors, avoidance of outdoor activities as much as possible, regular use of air purifiers at home and offices, minimize air pollution from cars and use public transport, and tree plantation are some of the measures to reduce smog effects.

Potential Impact of Smog on Human Health

Smog is a term used to describe pollution suspended in humid air. It's made up of different- sized dust particles, as well as non-metal oxides, organic compounds, and heavy metals. Apart from smoking cigarettes, one of the changeable variables leading to the development of respiratory diseases is exposure to toxic compounds dispersed in the air. . Smog is a visible form of air pollution that arises due to the over-emissions of some primary pollutants like volatile organic compounds (VOCs), hydrocarbons, SO, NO, and NO2 which further react in the atmosphere and give rise to toxic and carcinogenic secondary smog components. There are six categories of airborne chemicals that have a negative impact on public health and cause disease. Ozone, particulate matter (PM) of various dimensions - PM2.5, PM2.5–10, PM10, nitrogen – all has important implications. Lead, carbon dioxide, Sulphur dioxide, and carbon monoxide Small dust particles (PM10 and PM2.5) are given special attention since they can enter the lower respiratory tract. The page examines the impact of atmospheric pollutants on both the development and exacerbation of the disease, in addition to detailing the composition of smog and sources of air pollution. Asthma, chronic obstructive pulmonary disease, respiratory infections, and other respiratory tract illnesses can all cause symptoms. Lung cancer is a type of cancer that affects. Some of the legislative methods used in various nations to reduce exposure to harmful air pollution are presented.

Extraction and determination of organic/inorganic pollutants in the ambient air of two cities located in metropolis of Tehran.

In the present study, PM2.5, volatile organic compounds (VOC), heavy metals, and polycyclic aromatic hydrocarbons (PAHs)-bonded PM2.5 as well as asbestos fibers were investigated in two cities in the east of Tehran, Iran. To this end, 72 samples were collected from six stations located in the cities of Varamin and Pakdasht from March 2018 to March 2019. The concentration of BTEX compounds, PAHs, and heavy metals were measured using gas chromatography-flame ionization detector (GC-FID), gas chromatography-mass spectrometry (GC-Mas), and inductively coupled plasma atomic emission spectroscopy (ICP-OES), respectively. In addition, phase contrast microscopy (PCM) method was used to identify the properties of asbestos fibers. The results obtained from the present showed that the mean concentrations of PM2.5, heavy metals, PAHs, BTEX, and asbestos fibers were 52.05µg/m3, 319.08ng/m3, 3.97ng/m3, 40.58µg/m3, and 2.84 f/L, respectively. In addition, the results obtained from PCA and heavy metals sources showed that transport fleets were the natural source of most of these pollutants. In case of PAH sources, transport and incineration of coal had the highest contribution in the emission. Furthermore, the risk assessment showed that most of the compounds have a higher risk value than the guideline value spatial distribution and also showed that stations close to airports, city terminals, and highways were more polluted than other parts of the city. Therefore, in order to have healthy air and with the least pollution, it seems necessary to formulate the necessary strategies in the cities of Varamin and Pakdasht.

Exhaled Breath Semiconductor Sensors for Diagnostics of Respiratory Diseases

Respiratory diseases are common in humans. Rapid, risk-free and potentially inexpensive diagnostics of respiratory diseases observed in the patient's exhaled air is extremely important today. The following exhaled biomarkers are discussed: fractional exhaled nitric oxide, volatile organic compounds, carbon monoxide, hydrocarbons, and hydrogen peroxide. Breathomics from exhaled volatile organic compounds and oximeters are also shortly discussed.

The Potential Impact of Smog Spell on Humans' Health Amid COVID-19 Rages.

Rapid and unchecked industrialization and the combustion of fossil fuels have engendered a state of fear in urban settlements. Smog is a visible form of air pollution that arises due to the over-emissions of some primary pollutants like volatile organic compounds (VOCs), hydrocarbons, SO2, NO, and NO2 which further react in the atmosphere and give rise to toxic and carcinogenic secondary smog components. Smog reduces the visibility on roads and results in road accidents and cancellation of flights. Uptake of primary and secondary pollutants of smog is responsible for several deleterious diseases of which respiratory disorders, cardiovascular dysfunction, neurological disorders, and cancer are discussed here. Children and pregnant women are more prone to the hazards of smog. The worsening menace of smog on one hand and occurrence of pandemic i.e., COVID-19 on the other may increase the mortality rate. But the implementation of lockdown during pandemics has favored the atmosphere in some ways, which will be highlighted in the article. On the whole, the focus of this article will be on the dubious relationship between smog and coronavirus.

Applications and Limitations of Quantifying Speciated and Source-Apportioned VOCs with Metal Oxide Sensors

While low-cost air quality sensor quantification has improved tremendously in recent years, speciated hydrocarbons have received little attention beyond total lumped volatile organic compounds (VOCs) or total non-methane hydrocarbons (TNMHCs). In this work, we attempt to use two broad response metal oxide VOC sensors to quantify a host of speciated hydrocarbons as well as smaller groups of hydrocarbons thought to be emanating from the same source or sources. For sensors deployed near oil and gas facilities, we utilize artificial neural networks (ANNs) to calibrate our low-cost sensor signals to regulatory-grade measurements of benzene, toluene, and formaldehyde. We also use positive matrix factorization (PMF) to group these hydrocarbons along with others by source, such as wet and dry components of oil and gas operations. The two locations studied here had different sets of reference hydrocarbon species measurements available, helping us determine which specific hydrocarbons and VOC mixtures are best suited for this approach. Calibration fits on the upper end reach above R2 values of 0.6 despite the parts per billion (ppb) concentration ranges of each, which are magnitudes below the manufacturer’s prescribed detection limits for the sensors. The sensors generally captured the baseline trends in the data, but failed to quantitatively estimate larger spikes that occurred intermittently. While compounds with high variability were not suited for this method, its success with several of the compounds studied represents a crucial first step in low-cost VOC speciation. This work has important implications in improving our understanding of the links between health and environment, as different hydrocarbons will have varied consequences in the human body and atmosphere.

The Proof-of-Concept: The Transformation of Naphthalene and Its Derivatives into Decalin and Its Derivatives during Thermochemical Processing of Sewage Sludge

One solution for sewage sludge (SS) management is thermochemical treatment due to torrefaction and pyrolysis with biochar production. SS biochar may contain toxic volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs). This study aimed to determine the process temperature’s influence on the qualitative PAHs emission from SS-biochar and the transformation of PAHs contained in SS. SS was torrefied/pyrolyzed under temperatures 200–600 °C with 1 h residence time. The headspace solid-phase microextraction (SPME) combined with gas chromatography and mass spectrometry (HS-SPME-GC-MS) analytical procedure of VOCs and PAHs emission was applied. The highest abundance of numerous VOCs was found for torrefaction ranges of temperature. The increase of temperatures to the pyrolytic range decreased the presence of VOCs and PAHs in biochar. The most common VOCs emitted from thermally processed SS were acetone, 2-methylfuran, 2-butanone, 3-metylbutanal, benzene, decalin, and acetic acid. The naphthalene present in SS converted to decalin (and other decalin derivatives), which may lead to SS biochar being considered hazardous material.

Combustion products generated in simulated industrial fires

Studies of firefighter exposure to combustion products have focused predominantly on real or simulated residential structure fires, with few investigations considering industrial fire scenarios. This study measured the atmospheric concentrations of a variety of volatile organic compounds (VOCs), acid gases, and polycyclic aromatic hydrocarbons (PAHs) produced during fires in simulated industrial premises, as well as the deposition of PAHs onto the structural firefighting ensembles worn by the firefighters involved in extinguishment activities. Ingress of these combustion products into the structural firefighting ensembles during firefighting was also measured. Benzene concentrations of up to 23 mg/m3 and total PAH concentrations ranging from 1.7 to 8.6 mg/m3 were observed in personal air samples collected outside the structural firefighting ensembles, as well as a variety of acid gases including hydrogen chloride and hydrogen cyanide. Most combustion products detected outside the structural firefighting ensembles were also detected inside the ensembles, although often at much lower concentrations. The degree of protection observed was not uniform across all the combustion products investigated, with lower levels of protection found for gaseous combustion products such as benzene, xylene, hydrogen cyanide, and hydrochloric acid as compared with PAHs. Deposition of a variety of PAH compounds was observed on the outer surface of the structural firefighting ensembles, with total PAH concentrations ranging from 161 to 347 ng/cm2. While similar combustion products are involved in firefighter exposures during residential and industrial fires, deposition rates of PAHs, may be substantially higher during industrial firefighting. This research provides evidence supporting fireground decontamination measures for management of contamination of structural firefighting ensembles and equipment worn or carried by firefighters during firefighting activities. Further research is required to investigate the potential for dermal deposition of PAHs during actual industrial fire responses, and characterize which stages of fire and firefighting operations contribute the most to firefighters’ exposure to particular contaminants.

Ultra-responsive and selective of formic acid sensors based on flame-made SnO2 nanoparticles loaded with core-shell Ir-IrO2 nanocatalysts

0.1–2 wt% Ir-loaded tin dioxide (SnO2) nanoparticles were prepared via flame spray pyrolysis and investigated for sensing of formic acid (CH2O2). The structural morphologies of the materials were investigated by various X-ray spectroscopic and electron microscopic analyses. The results revealed that very fine secondary core-shell nanoparticles containing Ir° and Ir4+ species were decorated on the surfaces of cassiterite SnO2 nanoparticles, resulting in an increase of specific surface area and a small reduction of SnO2 crystallize size. The gas-sensing performances of all fabricated sensors were evaluated towards several volatile organic acids particularly CH2O2, volatile organic compounds and hydrocarbon gases at working temperature in the range of 200–400 °C in dry and humid air. The data revealed that the 1 wt% Ir-loaded SnO2 provided the optimal sensor response of ∼1.43 × 105 to 1000 ppm CH2O2 at an optimum working temperature of 350 °C. In addition, the sensors presented moderately low humidity effect on CH2O2 response and high CH2O2 selectivity against C2H5OH, CH3OH, C3H6O, C7H8, C6H6, C8H10, HCHO, CH4, H2, C2H4O2, C3H6O2, C4H8O2, C5H10O2 and C3H6O3. The electronic and gas-sensing mechanisms could be primarily ascribed to metal-metal-semiconductor heterojunctions and catalytic effects of Ir-IrO2 via oxygen spill-over and oxygen evolution reaction mechanisms. Therefore, the loading of catalytic core-shell Ir nanoparticles on SnO2 nanostructures was a highly promising approach to achieve ultrasensitive and selective sensing of formic acid.

Analysis of Environmental Variables and Carbon Input on Soil Microbiome, Metabolome and Disease Control Efficacy in Strawberry Attributable to Anaerobic Soil Disinfestation.

Charcoal rot and Fusarium wilt, caused by Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae, respectively, are major soil-borne diseases of strawberry that have caused significant crop losses in California. Anaerobic soil disinfestation has been studied as an industry-level option to replace soil fumigants to manage these serious diseases. Studies were conducted to discern whether Gramineae carbon input type, incubation temperature, or incubation duration influences the efficacy of this disease control tactic. In experiments conducted using ‘low rate’ amendment applications at moderate day/night temperatures (24/18 °C), and carbon inputs (orchard grass, wheat, and rice bran) induced an initial proliferation and subsequent decline in soil density of the Fusarium wilt pathogen. This trend coincided with the onset of anaerobic conditions and a corresponding generation of various anti-fungal compounds, including volatile organic acids, hydrocarbons, and sulfur compounds. Generation of these metabolites was associated with increases in populations of Clostridium spp. Overall, carbon input and incubation temperature, but not incubation duration, significantly influenced disease suppression. All Gramineae carbon inputs altered the soil microbiome and metabolome in a similar fashion, though the timing and maximum yield of specific metabolites varied with input type. Fusarium wilt and charcoal rot suppression were superior when anaerobic soil disinfestation was conducted using standard amendment rates of 20 t ha−1 at elevated temperatures combined with a 3-week incubation period. Findings indicate that anaerobic soil disinfestation can be further optimized by modulating carbon source and incubation temperature, allowing the maximum generation of antifungal toxic volatile compounds. Outcomes also indicate that carbon input and environmental variables may influence treatment efficacy in a target pathogen-dependent manner which will require pathogen-specific optimization of treatment protocols.

Henry’s law constants of volatile organic compounds between 0 and 95 °C – Data compilation and complementation in context of urban temperature increases of the subsurface

In urban areas with frequently occurring contamination by volatile organic hydrocarbons (VOC) possible uncontrolled contaminant mobilization e.g. by volatilization is feared in case of subsurface temperature increases induced by high temperature underground thermal energy storage (HT-UTES) or due to urban heat islands (UHI).However, volatilization of VOC is the main process utilized by thermal remediation approaches, wherefore a combination of contaminant remediation with UTES is increasingly discussed. To predict VOC volatilization under changing temperature conditions, which is substantially characterized by Henry’s law constants (H), temperature dependency of H must be known substance-specifically in the total concerned temperature range.To provide an overview of available H and to evaluate their quality, published data of 41 pollutants were compiled, revealing the need for further measurements above 40 °C for at least 24 compounds (as e.g. TCE/PCE, BTEX). Additionally, the temperature dependence of H was calculated based on the compiled data using an established temperature regression function. Furthermore, H was complementarily measured for 10 relevant VOCs between 10 and 90 °C using the EPICS-method (Equilibrium Partitioning In Closed Systems). The measurements quantified the expected strong increase in H with rising temperature while providing high data quality (R2 = 0.84–0.99, mostly low standard deviations), thus improving the general data availability of H for VOCs and extending the scope of the regression function. The newly measured data and enhanced evaluation of compiled data contribute to a more reliable assessment of the pollutant behaviour in terms of volatilization at elevated temperatures caused e.g. by UTES or UHI.

Phenolic Profile: Antimicrobial Activity and Antioxidant Capacity of Colocasia esculenta (L.) Schott.

The aim of the study was to investigate the presence of bioactive compounds in the ethanolic extract of C. esculenta by HPLC and GC methods. The identification of phytochemical compounds is based on the peak area, retention time and pharmacological actions. The HPLC chromatogram of ethanol extract showed the presence of 13 compounds namely, 6,2',4'-trimethoxyflavanone, benzoic acid, gallic acid, luteolin-6,8-C-diglucoside, catechin, chlorogenic acid , astilbin, quercitin, kampferol, and major compounds with high concentration of absorbance are , rutin, , vitexin, ellagic acid and caffeic acid. The GC analysis of petroleum ether of C. esculenta extract showed presence 31 saturated fatty acid ,volatile organic hydrocarbons and sesquiterpenes .The major components were determined as follows, saturated fatty acid, Stearic acid, Arachidonicacid, 8-Heptadecene, monounsaturated fatty acid, (S)-citronellic acid and volatile organic hydrocarbons, specifically, sesquiterpenes as D-Germacrene and Isoledene, The antimicrobial activity of ethanol extract showed characteristic zone of inhibition against six clinical pathogens. The highest zone of inhibition was observed at 100mg/ml concentration against , the (Gram Negative Bacteria) Proteus vulgaris (ATCC13315) at 15mm, while Escherichia coli (ATCC25955), at 13 mm and Pseudomonas aeruginosa (ATCC27853) at 12 mm , while the zone of inhibition against (Gram positive Bacteria ) Staphylococcus aureus (RCMB010010), at 14 mm, Enterococcus faecalis (ATCC 29212), at 12 mm ,and no effect against Bacillus subtitis (RCMB 015 (1) NRRL B-543) , when compared with the standard drugs Gentamicin . The antifungal activity against six Fungi, was Cryptococcus neoformans ( RCMB 0049001) at 16mm, Aspergillus fumigatus (RCMB 002008 ) at 11mm, Syncephalastrum racemosum RCM 016001 (1) at 10 mm, and Candida albicans (RCMB 005003 ATCC 10231 ) at 9 mm . The zone of inhibition was observed at 100 mg/ml concentration when compared with the standard drugs Ketoconazole with (MIC) 100 mg/ml . The antioxidant activities of the extracts were determined using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging . ethanol extract of C. esculenta exhibited with IC50 value (22 µg/mL), while the standard ascorbic acid with IC50 (11.4 µg/mL) .This result is promising The above findings may justify the medicinal uses of the plants. The results suggest that the leaves of C. esculenta are a good sources of bioactive compounds with potent antimicrobial and antioxidant substances.

Effect of low-level laser irradiation on cytotoxicity of benzene in human normal fibroblast cells.

Benzene is volatile organic hydrocarbon which is widely used in a wide range of industries. Studies have shown that exposure to benzene consequences serious health risks for human. Understanding the effect and risks of environmental hazard materials in the laser therapy of skin is interesting which can show useful or harmful role of these effects in therapies. In this study, the effect of low-level laser therapy was investigated on benzene-induced cytotoxicity on human skin fibroblast cells (HU02). Human skin fibroblast cells (HU02) were exposed to various concentrations of benzene (0-100μg/mL) and incubated for 2h. Then the effect of low-level laser therapy (LLLT) at 660-nm wavelength with 3J/cm2 energy for 90s was investigated on the viability of the cells exposed to benzene using MTT assay and inverted light microscope. The effect of low-level laser therapy on the viability of the cells was positive at concentrations 0-15μg/mL but negative at higher concentrations than 15μg/mL. Low-level laser therapy in low concentrations of benzene decreases the cytotoxicity caused by benzene and maintains cell viability. At high concentrations and in the presence of low-level laser therapy, the cell viability decreased compared to dark experiment. The morphology study of the cells using inverted light microscopy has confirmed the MTT results.

Quantification of Seven Terpenes in Human Serum by Headspace Solid-Phase Microextraction-Gas Chromatography-Tandem Mass Spectrometry.

Terpenes are a class of volatile organic hydrocarbons commonly produced by vegetation and released into the atmosphere. These compounds are responsible for the scents of pine forests, citrus fruits, and some flowers. Human terpene exposure can come from inhalation, diet, smoking, and more recently, using e-cigarettes. Terpenes are present in tobacco smoke and are used as flavor chemicals in e-liquids. The health effects of terpenes are not widely known, though several studies have suggested that they may prove useful in future medical applications. We have developed a novel, high-throughput method of quantifying seven terpenes (α-pinene, β-pinene, β-myrcene, 3-carene, limonene, β-caryophyllene, and α-humulene) in human serum to aid human-exposure investigations. This method employs headspace sampling using solid-phase microextraction (SPME) coupled to gas chromatography-tandem mass spectrometry to detect and quantify five monoterpenes and two sesquiterpenes in the low parts-per-trillion to low parts-per-billion range. The intraday and interday variability (percent error) of the method are ≤2 and ≤11%, respectively. In addition, this method showed excellent recovery in human serum (between 80 and 120% for all analytes). The assay precision ranges between 4.0 and 11%. Limits of detection ranged between 0.032 and 0.162 μg/L. Using serum cotinine values to classify tobacco use showed that smokers have higher serum concentrations of six terpenes compared to nonusers. Terpene concentrations were 14-78% higher in smokers than nonusers. Our method can provide essential biomonitoring data to establish baseline exposure levels for terpenes in humans.

Emissions of volatile hydrocarbons from floating roof tanks and their local dispersion: Considerations for normal operation and in case of damage

This work investigates the release and dispersion of volatile organic hydrocarbons, which may escape from external floating roof tanks (EFRT) during normal operation or in case of damage. The dispersion will be described using CFD simulations in close range of the EFRT where hazardous areas are assigned. The aim of this work is to investigate which events can lead to emissions in dangerous quantities and to estimate the corresponding likelihood with regard to explosion protection. An emission in hazardous amount is present if the lower explosion limit has been exceeded and if the extent of this emission is not too low. It is discussed in particular whether the used zoning of potentially explosive areas is conservative or over-conservative.