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Benzene guideline

Axel Wuttke, Ricardo A Mata
The interpretation of chemical properties/phenomena can often be aided through the use of imagery. The mapping of molecular electrostatic potentials is a prime example, serving as a guideline in the design of novel compounds or understanding transition state stabilization effects. It is today a common tool for theoreticians and experimentalists alike. With the emergence of concepts such as dispersion energy donors, and the overall importance of dispersion in chemical systems, representations targeting such a class of interactions are warranted...
October 20, 2016: Journal of Computational Chemistry
Jennifer Z Menzies, Kathleen McDonough, Drew McAvoy, Thomas W Federle
The ultimate disposition of chemicals discarded down the drain can be substantially impacted by their fate in the sewer, but to date limited data have been published on the biodegradability of chemicals in sewer systems. The recently established OECD 314 guideline (Simulation tests to assess the biodegradability of chemicals discharged in wastewater, 2008) contains a simulation method (314A) for evaluating the biodegradation of chemicals in sewage under simulated sewer conditions. This research used the OECD 314A method to evaluate the rates and pathways of primary and ultimate biodegradation of a suite of (14)C-labeled homologues representing four classes of high volume surfactants including nonionic alkyl ethoxylates (AE), and anionic alkyl ethoxysulfates (AES), alkyl sulfate (AS) and linear alkyl benzene sulfonate (LAS)...
September 23, 2016: Biodegradation
Tina Hoang, Rosemary Castorina, Fraser Gaspar, Randy Maddalena, Peggy L Jenkins, Qunfang Zoe Zhang, Thomas E McKone, Emilio Benfenati, Alex Y Shi, Asa Bradman
Little information exists about exposures to volatile organic compounds (VOCs) in early childhood education (ECE) environments. We measured 38 VOCs in single-day air samples collected in 2010-2011 from 34 ECE facilities serving California children and evaluated potential health risks. We also examined unknown peaks in the GC/MS chromatographs for indoor samples and identified 119 of these compounds using mass spectral libraries. VOCs found in cleaning and personal care products had the highest indoor concentrations (d-limonene and decamethylcyclopentasiloxane [D5] medians: 33...
September 22, 2016: Indoor Air
Marta Jatczak, Katarzyna Sidoryk, Magdalena Kossykowska, Wojciech Łuniewski, Joanna Zagrodzka, Elżbieta Lipiec-Abramska
Bosentan monohydrate (4-tert-butyl-N-[6-(2-hydroxyethoxy)-5-(2-methoxyphenoxy)-2-(pyrimidin-2-yl) pyrimidin-4-yl]benzene-1-sulfonamide monohydrate) is a dual endothelin receptor antagonist (ERA) applied in the treatment of pulmonary arterial hypertension. To achieve effective process control of the bosentan monohydrate synthesis, it was necessary to develop a selective and not highly time-consuming method for ultra-high performance liquid chromatography (UHPLC). The method is characterized by adequate sensitivity, reproducibility and selectivity for the determination of bosentan monohydrate and related compounds from all synthetic stages...
2016: Chromatographia
Deepak Singh, Amit Kumar, Krishan Kumar, Bupender Singh, Usha Mina, Braj Bihari Singh, Vinod Kumar Jain
Indoor Air Quality (IAQ) is considered to be of great concern due to its adverse impact on the human health nowadays. The presence of different air pollutants along with noise may aggravate the IAQ. The present study attempts to examine IAQ in terms of major criteria air pollutants (O3, NOx=NO+NO2, CO and PM2.5) along with total volatile organic compound (TVOC), individual VOC and noise pollution in indoor and outdoor environment of a Commercial Shopping Complex (CSC) in Delhi. Real time measurements have been carried out for O3, NOx, CO, PM2...
August 27, 2016: Science of the Total Environment
Pamela Cabarcos, Paloma Herbello-Hermelo, Iván Álvarez-Freire, Antonio Moreda-Piñeiro, María Jesús Tabernero, Ana María Bermejo, Pilar Bermejo-Barrera
A simple sample pre-treatment method based on solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) has been optimized and validated for the assessment of 15 residual solvents (2-propanol, 2-methylpentane, 3-methylpentane, acetone, ethyl acetate, benzene, hexane, methylcyclohexane, methylcyclopentane, m-xylene, propyl acetate, toluene, 1,2,4-trimethylbenzene, dichloromethane, and ethylbenzene) in seized illicit cocaine and heroin. DMSO and DMF as sample diluents were found to offer the best residual solvent transference to the head space for further adsorption onto the SPME fiber, and the developed method therefore showed high sensitivity and analytical recovery...
September 2016: Analytical and Bioanalytical Chemistry
Yan-Yang Lu, Yi Lin, Han Zhang, Dongxiao Ding, Xia Sun, Qiansheng Huang, Lifeng Lin, Ya-Jie Chen, Yu-Lang Chi, Sijun Dong
An air-conditioned coach is an important form of transportation in modern motorized society; as a result, there is an increasing concern of in-vehicle air pollution. In this study, we aimed to identify and quantify the levels of volatile organic compounds (VOCs) and carbonyl compounds (CCs) in air samples collected from the cabins of newly produced, medium- and large-size coaches. Among the identified VOCs and CCs, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, acrolein/acetone, and isovaleraldehyde were relatively abundant in the cabins...
2016: International Journal of Environmental Research and Public Health
Iason Verginelli, Oriana Capobianco, Renato Baciocchi
The adoption of source to building separation distances to screen sites that need further field investigation is becoming a common practice for the evaluation of the vapor intrusion pathway at sites contaminated by petroleum hydrocarbons. Namely, for the source to building vertical distance, the screening criteria for petroleum vapor intrusion have been deeply investigated in the recent literature and fully addressed in the recent guidelines issued by ITRC and U.S.EPA. Conversely, due to the lack of field and modeling studies, the source to building lateral distance received relatively low attention...
June 2016: Journal of Contaminant Hydrology
Maude Giroud, Michael Harder, Bernd Kuhn, Wolfgang Haap, Nils Trapp, W Bernd Schweizer, Tanja Schirmeister, François Diederich
The π-stacking of fluorinated benzene rings on protein backbone amide groups was investigated, using a dual approach comprising enzyme-ligand binding studies complemented by high-level quantum chemical calculations. In the experimental study, the phenyl substituent of triazine nitrile inhibitors of human cathepsin L (hCatL), which stacks onto the peptide amide bond Gly67-Gly68 at the entrance of the S3 pocket, was systematically fluorinated, and differences in inhibitory potency were measured in a fluorimetric assay...
May 19, 2016: ChemMedChem
Congrong He, Branka Miljevic, Leigh R Crilley, Nicholas C Surawski, Jennifer Bartsch, Farhad Salimi, Erik Uhde, Jürgen Schnelle-Kreis, Jürgen Orasche, Zoran Ristovski, Godwin A Ayoko, Ralf Zimmermann, Lidia Morawska
Open biomass burning from wildfires and the prescribed burning of forests and farmland is a frequent occurrence in South-East Queensland (SEQ), Australia. This work reports on data collected from 10 to 30 September 2011, which covers the days before (10-14 September), during (15-20 September) and after (21-30 September) a period of biomass burning in SEQ. The aim of this project was to comprehensively quantify the impact of the biomass burning on air quality in Brisbane, the capital city of Queensland. A multi-parameter field measurement campaign was conducted and ambient air quality data from 13 monitoring stations across SEQ were analysed...
May 2016: Environment International
Moreno Paolini, Fabio Vivarelli, Andrea Sapone, Donatella Canistro
For the first time, the aspartame case shows how a corporation decided to ban an artificial ingredient in the wake of public opinion notwithstanding the regulatory assurance claims that it is safe. PepsiCo Inc. made an unprecedented decision most likely based on life-span carcinogenicity bioassay studies from the Cesare Maltoni Cancer Research Center of the Ramazzini Institute (CMCRC/RI), which provide consistent evidence of aspartame's carcinogenicity in rodents. Although CMCRC/RI experiments have been criticized for not complying with Organisation for Economic Co-operation and Development (OECD) guidelines, the newly launched aspartame-free soft drink may not be an isolated case...
February 24, 2016: Carcinogenesis
Pan Hu, Sangsu Lee, Tun Seng Herng, Naoki Aratani, Théo P Gonçalves, Qingbiao Qi, Xueliang Shi, Hiroko Yamada, Kuo-Wei Huang, Jun Ding, Dongho Kim, Jishan Wu
Open-shell singlet diradicaloids display unique electronic, nonlinear optical, and magnetic activity and could become novel molecular materials for organic electronics, photonics, and spintronics. However, design and synthesis of diradicaloids with a significant polyradical character is a challenging task for chemists. In this Article, we report our efforts toward a tetraradicaloid system. A series of potential tetraradicaloids by fusion of two p-quinodimethane (p-QDM) units with naphthalene or benzene rings in different modes were synthesized...
January 27, 2016: Journal of the American Chemical Society
Sung Min Cho, Bum Su Park, Woo Sung Jung, Sang Won Lee, Yunhwan Jung, Doo Soo Chung
Headspace (HS) extraction can be carried out easily and aptly via single drop microextraction coupled with capillary electrophoresis (CE). However, one drawback is the difficulty of keeping the single drop stably at the capillary tip. To solve this problem, we have recently demonstrated HS in-tube microextraction (ITME) of acidic compounds such as chlrophenols in an acidic sample using a basic run buffer plug in the separation capillary for CE as an acceptor phase. In this report, an organic acceptor plug in a capillary was used to extract neutral organic volatile pollutants such as BTEX (benzene, toluene, ethylbenzene, and m-xylene)...
February 1, 2016: Talanta
Kenichi Azuma, Iwao Uchiyama, Shigehisa Uchiyama, Naoki Kunugita
Over the past few decades, multiple low level indoor pollutants have been found in domestic dwellings. The types and concentrations of these indoor pollutants have not been consistent over time and have changed with alterations in lifestyle, the development of novel products used in housing, and the development of new measurement technologies. To clarify the highest risk pollutants for which health risks should be reduced, we conducted a health risk assessment of 49 indoor air pollutants measured in 602 houses during winter and summer from 2012 to 2014...
February 2016: Environmental Research
Tomofumi Tada, Kazunari Yoshizawa
In this study, we report our viewpoint of single molecular conductance in terms of frontier orbitals. The orbital rule derived from orbital phase and amplitude is a powerful guideline for the qualitative understanding of molecular conductance in both theoretical and experimental studies. The essence of the orbital rule is the phase-related quantum interference, and on the basis of this rule a constructive or destructive pathway for electron transport is easily predicted. We have worked on the construction of the orbital rule for more than ten years and recently found from its application that π-stacked molecular junctions fabricated experimentally are in line with the concept for conductance-decay free junctions...
December 28, 2015: Physical Chemistry Chemical Physics: PCCP
Sanghwa Kim, Seong-Ho Hong, Choon-Keun Bong, Myung-Haing Cho
Air freshener could be one of the multiple sources that release volatile organic compounds (VOCs) into the indoor environment. The use of these products may be associated with an increase in the measured level of terpene, such as xylene and other volatile air freshener components, including aldehydes, and esters. Air freshener is usually used indoors, and thus some compounds emitted from air freshener may have potentially harmful health impacts, including sensory irritation, respiratory symptoms, and dysfunction of the lungs...
2015: Journal of Toxicological Sciences
Neelofar Khan, Aditya Ganeshpurkar, Nazneen Dubey, Divya Bansal
OBJECTIVES: Wheat grass (Triticum aestivum) is a gift of nature given to mankind. A number of scientific research on wheatgrass establishes its anticancer and antioxidant potential. Current work was focused to determine antileukemic effect of wheat grass. MATERIALS AND METHODS: The commercial wheatgrass powder was extracted with 95% of methanol. Methanol extract of wheat grass was studied for acute oral toxicity as per revised Organization for Economic Cooperation and Development Guidelines number 423...
July 2015: Indian Journal of Pharmacology
Raeesa Moolla, Christopher J Curtis, Jasper Knight
Of increasing concern is pollution by volatile organic compounds, with particular reference to five aromatic hydrocarbons (benzene, toluene, ethyl benzene and two isomeric xylenes; BTEX). These pollutants are classified as hazardous air pollutants. Due to the potential health risks associated with these pollutants, BTEX concentrations were monitored at a bus diesel-refueling bay, in Johannesburg, South Africa, using gas chromatography, coupled with a photo-ionization detector. Results indicate that o-xylene (29-50%) and benzene (13-33%) were found to be the most abundant species of total BTEX at the site...
December 15, 2015: Science of the Total Environment
Farahnaz Rezaei Makhuri, Jahan B Ghasemi
In this study as the first attempt; comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) and AutoGPA-based 3D-QSAR methods were applied on a set of 47 recently reported Ck1d inhibitors, in order to gain an insight into the structural requirements which providing guidelines for the design of next generation compounds with enhanced bioactivity. The results of 3D-QSAR analyses indicated that hydrophobic and negatively charged groups at 6th position of benzothiazole ring and positively charged and bulky groups at ortho position of phenyl ring are favorable for high activity...
October 12, 2015: European Journal of Pharmaceutical Sciences
Anupam Ghorai, Jahangir Mondal, Rukmani Chandra, Goutam K Patra
A reversible fluorescent-colorimetric imino-pyridyl bis-Schiff base receptor (N(1)E,N(4)E)-N(1),N(4)-bis(pyridine-4-ylmethylene)benzene-1,4-diamine for the detection of both Al(3+) and HSO3(-) in aqueous medium has been developed. Receptor exhibits an excellent selective fluorescent-colorimetric response toward Al(3+). The sensitivity of the fluorescent based assay (0.903 μM) for Al(3+) is far below the limit recommended in the World Health Organization (WHO) guidelines for drinking water (7.41 μM). From (1)H NMR data, the Job plot and the ESI-MS spectrum, 1 : 2 stoichiometric complexation between and Al(3+) has been established...
August 7, 2015: Dalton Transactions: An International Journal of Inorganic Chemistry
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