2-Aminothiophenol as building blocks for novel heterocycles

Herein, the chemistry of 2-aminothiophenol has been utilized in the synthesis of several interesting products such as oxidation and reaction with π-deficient compounds. On oxidizing 2-aminothiophenol by sodium hypochlorite furnishes 2-[(2-aminophenyl)-dithio]aniline. Treatment of the obtained product with acetyl chloride affords N-(2-[2-(acetylamino)-phenyl-disulphanyl)-phenyl]acetamide. Reaction of the former acetamide with POCl₃ yields 2-methyl-1,3-benzothiazole. Moreover, (3,4,8,9)-dibenzo-2,7-dithia-5,10-diaza4 Field, L. and Lawson, J. E. 1958. J. Am. Chem. Soc., 80: 838[Crossref], [Web of Science ®] , [Google Scholar] 4 Field, L. and Lawson, J. E. 1958. J. Am. Chem. Soc., 80: 838[Crossref], [Web of Science ®] , [Google Scholar] 4 Field, L. and Lawson, J. E. 1958. J. Am. Chem. Soc., 80: 838[Crossref], [Web of Science ®] , [Google Scholar]propellane is formed on reacting the target 2-aminothiophenol with cyclohexane-1,2-dione, whereas its reactions with electron π-acceptors such as 2,3-dichloro-1,4-naphthoquinone (DCHNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetra-cyanoethylene (TCNE), and 1-(dicyanomethylen)acenaphthen-2-one yield various heterocycles.     

Design,synthesis, and preliminary evaluation as antimicrobial activity of novel spiro-1, 3-thiazolidine C-acyclic nucleoside analogs

Synthesis of a new class of 1, 3-thiazolidine nucleoside analogs is described. Reaction of 2-amino-2-deoxy-D-glucopyranose hydrochloride 2 with carbon disulfide yielded 5-hydroxy-4-(D-arabino-1, 2, 3, 4-tetrahydroxybutyl)-thiazolidin-2-thione 3, which on acetylation yielded 5-acetoxy-4-(D-arabino-1, 2, 3, 4-tetraacetoxy-butyl)-thiazolidin-2-thione 4. The acetylated sugar 4 reacted with hydrazonoyl chlorides 1a–f, affording the 5-acetoxy-4-(D-arabino-1, 2, 3, 4-tetraacetoxybutyl)-spiro-1 Chen, H., Fan, Y-H., Natarajan, A., Guo, Y., Iyasere, J., Harbinski, F., Luus, L., Christ, W., Aktas, H. and Halperin, J. A. 2004. Bioorg. Med. Chem. Lett., 14: 5401–5405. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] 3 Nasr, M. N., Gineinah, M. M. and El-Bendary, E. R. 2003. Arch. Pharm., 336: 560–566. [Crossref] , [Google Scholar]thiazolidine-2,2′ -1 Chen, H., Fan, Y-H., Natarajan, A., Guo, Y., Iyasere, J., Harbinski, F., Luus, L., Christ, W., Aktas, H. and Halperin, J. A. 2004. Bioorg. Med. Chem. Lett., 14: 5401–5405. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] 3 Nasr, M. N., Gineinah, M. M. and El-Bendary, E. R. 2003. Arch. Pharm., 336: 560–566. [Crossref] , [Google Scholar] 4 Belleau, B., Brasilli, L., Chan, L. and Zacheri, B. 1993. Cameron J. Bioorg. Med. Chem. Lett., 3: 1723–1928. [Crossref], [Web of Science ®] , [Google Scholar]thiadiazole derivatives 8a–f. The antibacterial activity of the novel 1, 3-thiazolidine-2,2′ -spiro- 1 Chen, H., Fan, Y-H., Natarajan, A., Guo, Y., Iyasere, J., Harbinski, F., Luus, L., Christ, W., Aktas, H. and Halperin, J. A. 2004. Bioorg. Med. Chem. Lett., 14: 5401–5405. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] 3 Nasr, M. N., Gineinah, M. M. and El-Bendary, E. R. 2003. Arch. Pharm., 336: 560–566. [Crossref] , [Google Scholar] 4 Belleau, B., Brasilli, L., Chan, L. and Zacheri, B. 1993. Cameron J. Bioorg. Med. Chem. Lett., 3: 1723–1928. [Crossref], [Web of Science ®] , [Google Scholar]thiadiazole nucleoside analogs is highlighted. All compounds with free NH group in the thiazolidine series 8a–f showed significant biological activity against all the standard strains.     

Quantification of Carboxylic and Carbonyl Functional Groups in Organic Aerosol Infrared Absorbance Spectra

Atmospheric aerosols are one of the least understood components of the climate system and incur adverse health effects on susceptible populations. Organic aerosols can make up as much as 80% of atmospheric aerosols (Lim and Turpin 2002 Lim, H. J. and Turpin, B. J. 2002. Origins of Primary and Secondary Organic Aerosol in Atlanta: Results’ of Time-Resolved Measurements During the Atlanta supersite experiment. Environ. Sci. Technol., 36: 4489–4496. 10.1021/es0206487[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), and so its quantification and characterization plays an important role in reducing our uncertainty with regards to aerosol impacts on health and climate. As the number of organic molecules in the atmosphere are diverse in number (Hamilton et al. 2004 Hamilton, J. F., Webb, P. J., Lewis, A. C., Hopkins, J. R., Smith, S. and Davy, P. 2004. Partially Oxidised Organic Components in Urban Aerosol using GCXGC-TOF/MS. Atmos. Chem. Phys., 4: 1279–1290. [Crossref], [Web of Science ®] , [Google Scholar]), we advance a functional group representation of organic molecules as measured by Fourier transform infrared spectroscopy (FTIR) to characterize the chemical composition of particle samples. This study describes and evaluates the algorithm introduced by Russell et al. (2009 Russell, L. M., Takahama, S., Liu, S., Hawkins, L. N., Covert, D. S.Quinn, P. K. 2009. Oxygenated Fraction and Mass of Organic Aerosol from Direct Emission and Atmospheric Processing Measured on the R/V Ronald Brown During TEXAQS/GoMACCS 2006. J. Geophys. Res.-Atmos., 114: D00F05 10.1029/2008JD011275[Crossref], [Web of Science ®] , [Google Scholar]) for apportionment and quantification of oxygenated (carbonyl and hydroxyl) functional groups from infrared absorption spectra. Molar absorptivities for carbonyl and hydroxyl bonds in carboxylic groups are obtained for several dicarboxylic compounds, and applied to a multifunctional compound and mixture to demonstrate the applicability of this method for more complex samples. Furthermore, functional group abundances of two aldehydic compounds, 2-deoxy-d-ribose and glyceraldehyde, atomized from aqueous solution are in quantitative agreement with number of bonds predicted after transformation of these compounds into diols. The procedure for spectra interpretation and quantitative analysis is described through the context of an algorithm in which contributions of background and analyte absorption to the infrared spectrum are apportioned by the superposition of lineshapes constrained by laboratory measurements.

Copyright 2013 American Association for Aerosol Research     

Theory of Multi-Nozzle Impactor Stages and the Interpretation of Stage Mensuration Data

We describe a general theory of multi-nozzle cascade impactor stages and show how testers of inhaled drug products, such as metered-dose or dry-powder inhalers, can decide, solely from the stage nozzle dimensions, whether any used impactor is satisfactorily operating within its expected aerodynamic performance range. We first account for the realistic shape of particle collection efficiency curves and show that the effective diameter, described by Roberts and Romay (2005) Roberts D. L.Romay F. J.Relationship of Stage Mensuration Data to the Performance of New and Used Cascade ImpactorsJ. Aerosol Med2005184396–413[Crossref], [PubMed] , [Google Scholar], is sufficiently accurate as the primary indication of the aerodynamic performance.

To ensure that a used impactor is performing in the same aerodynamic range allowed for new impactors, one must also satisfy the other, more secondary factors of cascade impaction aerodynamics, most notably the distance to the collection surface relative to the nozzle diameter. We show what this constraint means in practice for used Next Generation Impactors (NGIs; Marple et al. 2003a Marple V. A.Roberts D. L.Romay F. J.Miller N. C.Truman K. G.Van Oort M.Olsson B.Holroyd M. J.Mitchell J. P.Hochrainer D.Next Generation Pharmaceutical Impactor, Part I: DesignJ. Aerosol Med2003a16283–299[Crossref], [PubMed] , [Google Scholar], b Marple V. A.Olson B. A.Santhanakrishnan K.Mitchell J. P.Murray S. C.Hudson-Curtis B. L.Next Generation Pharmaceutical Impactor—Part II: Archival CalibrationJ. Aerosol Med2003b16[Crossref], [PubMed] , [Google Scholar]; 2004 Marple V. A.Olson B. A.Santhanakrishnan K.Roberts D. L.Mitchell J. P.Hudson-Curtis B. L.Next Generation Pharmaceutical Impactor: A New Impactor for Pharmaceutical Inhaler Testing. Part III. Extension of Archival Calibration to 15 L/minJ. Aerosol Med200417335–343[Crossref], [PubMed] , [Google Scholar]), and show that partially occluded nozzles are the most likely nozzles to fail this test.

Applying this principle that used impactors should perform in the same aerodynamic range as new impactors, we derive constraints on the nozzle diameters of any used NGI (Table 6, main text). We can partially apply this principle to other common impactors used for inhaler testing, such as the Andersen and the Marple-Miller, but are hindered by the absence of a published acceptable range for the distance to the impaction collection surface and by the limited published information on the shape of their stage collection efficiency curves.     

DYNAMICS OF IMINE AND ACETOPHENONE DERIVATIVES IN SOLUTION STUDIED BY ONE-DIMENSIONAL DIFFUSION-ORDERED NMR SPECTROSCOPY (DOSY)

This paper describes the usefulness of one-dimensional diffusion-ordered NMR spectroscopy (1D-DOSY) in investigating dynamics and interactions of molecules in solution as well as in analyzing the structure of molecules. We synthesized the three imines, N-benzylidene-4-methylbenzene-Sulfonamide (1 Kondo, K., Kazuta, K., Saitoh, A. and Murakami, Y. 2003. Heterocycles, 59: 97–100.  [Google Scholar]), N-(4-chloro-benzylidene)4-methyl-benzene-sulfonamide (2 Horibe, H., Kazuta, K., Kotoku, M., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2003. Synlett, : 2047–2051. [Web of Science ®] , [Google Scholar]), and N- (4-methoxybenzylidene)-4-methyl-benzene sulfonamide (3 Horibe, H., Fukuda, Y., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2004. Tetrahedron, 60: 10701–10709. [Crossref], [Web of Science ®] , [Google Scholar]), and acetophenone (4 Sakamoto, Y., Kondo, K., Tokunaga, M., Kazuta, K., Fujita, H., Murakami, Y. and Aoyama, T. 2004. Heterocycles, 63: 1345–1357. [Crossref], [Web of Science ®] , [Google Scholar]) and its three derivatives, 4-chloroacetophenone (5 Sakamoto, Y., Kondo, K., Onozato, M. and Aoyama, T. 2006. Polycycl. Aromat. Comp., 26: 59–68. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), 4-nitro-acetophenone (6 Kondo, K., Kazuta, K., Fujita, H., Sakamoto, Y. and Murakami, Y. 2002. Tetrahedron, 58: 5209–5214. [Crossref], [Web of Science ®] , [Google Scholar]), and 4-methoxyaceto -phenone (7 Gostam, T., Morean, C., Jutean, A., Guichard, E. and Delsuc, M. A. 2004. Magn. Reson. Chem., 42: 496–499.  [Google Scholar]). 1D-DOSY was applied to a mixture of compounds (1 Kondo, K., Kazuta, K., Saitoh, A. and Murakami, Y. 2003. Heterocycles, 59: 97–100.  [Google Scholar]), (2 Horibe, H., Kazuta, K., Kotoku, M., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2003. Synlett, : 2047–2051. [Web of Science ®] , [Google Scholar]), and (3 Horibe, H., Fukuda, Y., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2004. Tetrahedron, 60: 10701–10709. [Crossref], [Web of Science ®] , [Google Scholar]) and to a mixture of compounds (4 Sakamoto, Y., Kondo, K., Tokunaga, M., Kazuta, K., Fujita, H., Murakami, Y. and Aoyama, T. 2004. Heterocycles, 63: 1345–1357. [Crossref], [Web of Science ®] , [Google Scholar]), (5 Sakamoto, Y., Kondo, K., Onozato, M. and Aoyama, T. 2006. Polycycl. Aromat. Comp., 26: 59–68. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), (6 Kondo, K., Kazuta, K., Fujita, H., Sakamoto, Y. and Murakami, Y. 2002. Tetrahedron, 58: 5209–5214. [Crossref], [Web of Science ®] , [Google Scholar]), and (7 Gostam, T., Morean, C., Jutean, A., Guichard, E. and Delsuc, M. A. 2004. Magn. Reson. Chem., 42: 496–499.  [Google Scholar]). Although ¹ H NMR chemical shifts of the molecules in the mixtures resembled one another in the surrounding, we could distinguish signals of the individual molecules in each mixture on the basis of the NMR data and the values of the diffusion coefficient. Also, we could found the correlation of the measured diffusion coefficients and the calculated molecular volumes.     

Methodology for Performance Evaluation of Dust Control Systems with an Application to Electrostatic Precipitators

A general methodology is presented that enables rigorous estimation of the total collection efficiency and the size distribution of particles penetrating dust control systems. This methodology assumes lognormal inlet particle-size distributions and can be used with fractional efficiency formulations that predict, under such conditions, lognormal outlet particle-size distributions. Multimodal inlet particle distributions can be accommodated additively. This methodology is applied to Electrostatic Precipitator Systems (ESPs), with the Nobrega et al. (2004) Nobrega, S. W., Falaguasta, M. C. R. and Coury, J. R. 2004. A Study of a Wire-Plate Electrostatic Precipitator Operating in the Removal of Polydispersed Particles. Braz. J. Chem. Eng., 21(2): 275–284. [Crossref], [Web of Science ®] , [Google Scholar] model selected for predicting their fractional efficiencies. For ease of use, a graphical solution has been developed for the Nobrega et al. fractional efficiency relations, but its availability is not a prerequisite for the application of the general methodology. For the latter, the fractional efficiencies corresponding to three particle diameters need to be estimated and this can be done either graphically or numerically using the model of Nobrega et al. or any other fractional efficiency formulation of interest.

Fine particles emerge as the most important pollutant worldwide in terms of human health, creating thus the need for credible particle size-specific inventories. In line with the above, a generic and rigorous method, capable of producing size-specific emission estimates from uncontrolled and controlled sources, has been developed (Economopoulou and Economopoulos 2001 Economopoulou, A. A. and Economopoulos, A. P. 2001. Method for Estimating Size-Specific Particulate Emission Inventories. J. Environ. Eng., ASCE, 127: 1139–1148. [Crossref], [Web of Science ®] , [Google Scholar]). For controlled sources, this method relies on the development of easy to use models that predict the total efficiency and the lognormal size distribution of particles penetrating the control systems used. Such models have already been developed for dry cyclone separators (Economopoulou and Economopoulos 2002a Economopoulou, A. A. and Economopoulos, A. P. 2002a. Rapid Performance Evaluation and Optimal Sizing of Dry Cyclone Separators. J. Environ. Eng., ASCE, 128: 275–285. [Crossref], [Web of Science ®] , [Google Scholar], 2002b Economopoulou, A. A. and Economopoulos, A. P. 2002b. Size Distribution of Particles Penetrating Dry Cyclone Separators. J. Environ. Eng., ASCE, 128: 919–928. [Crossref], [Web of Science ®] , [Google Scholar]) and venturi scrubbers (Economopoulou and Harrison 2007a Economopoulou, A. A. and Harrison, R. M. 2007a. Graphical Analysis of the Performance of Venturi Scrubbers for Particle Abatement. Part I: Rapid Collection Efficiency Evaluation. Aerosol Sci. Technol., 41: 51–62. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], 2007b Economopoulou, A. A. and Harrison, R. M. 2007b. Graphical Analysis of the Performance of Venturi Scrubbers for Particle Abatement. Part II: Size Distribution of Penetrating Particles. Aerosol Sci. Technol., 41: 63–74. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). The present methodology extends the use of the inventory methodology to ESP-controlled sources and, in addition, it provides a generalized basis for covering other types of control systems with any fractional efficiency formulation considered appropriate.     

SYNTHESES OF ADDUCTS OF ACTIVE METABOLITES OF CARCINOGENIC POLYCYCLIC AROMATIC HYDROCARBONS WITH 2′-DEOXYRIBONUCLEOSIDES

Syntheses are reported for: (1 Harvey, R. G. 1991. Polycyclic Aromatic Hydrocarbons: Chemistry and Carcinogenicity, Cambridge, , U.K.: Cambridge University Press.  [Google Scholar]) adducts of the quinone metabolites of benzo[a]pyrene (BPQ) and benz[a]anthracene (BAQ) with 2′-deoxyadenosine and 2′-deoxyguanosine; (2 Conney, A. H. 1982. Induction of Microsomal Enzymes by Foreign Chemicals and Carcinogenesis by Polycyclic Aromatic Hydrocarbons. Cancer Res., 42: 4875–4917. [PUBMED][INFOTRIEVE][CSA][PubMed], [Web of Science ®] , [Google Scholar]) ¹⁵ N-labelled analogs of these adducts (four or five nitrogen atoms ¹⁵ N-labelled); (3 Dipple, A. 1994. “Reactions of Polycyclic Aromatic Hydrocarbons with DNA”. In DNA Adducts: Identification and Biological Significance, Edited by: Hemminki, K., Dipple, A., Segerbäck, D., Kadulbar, F. F., Shuker, D. and Bartsch, H. pp. 107–129. IARC Scientific Publication No. 125.  [Google Scholar]) depurinated adducts of BPQ and BAQ with adenine or guanine covalently linked to the N7 or N9 positions of the purine bases; (4 Jeffrey, A. M., Weinstein, I. B., Jennette, K., Grzeskowiak, K., Nakanishi, K., Harvey, R. G., Autrup, H. and Harris, C. 1977. Structures of Benzo[a]pyrene-Nucleic Acid Adducts Formed in Human and Bovine Bronchial Explants. Nature (London)., 269: 348–350. [CSA][CROSSREF][Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) ¹³ C-labelled derivatives of benzo[a]pyrene, BPQ, benzo[a]pyrene trans-7,8-dihydrodiol, and the benzo[a]pyrene anti-diol epoxide (with ¹³ C-atoms at the 5- and 11-positions); and (5 Jennette, K., Jeffrey, A. M., Blobstein, S. H., Beland, F. A., Harvey, R. G. and Weinstein, I. B. 1977. Characterization of Nucleoside Adducts from the in Vitro Reaction of Benzo[a]pyrene-7,8-dihydrodiol-9,10-oxide or Benzo[a]pyrene-4,5-oxide with Nucleic Acids. Biochemistry, 16: 932–938. [PUBMED][INFOTRIEVE][CSA][CROSSREF][Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) depurinated adducts formed by reactions of the benzo[a]pyrene radical-cation at the C ⁸ -, N ⁷ -, and N ⁹ -positions of adenine and guanine.     

Pyrido[2,3-d]pyrimidine-2,7-dithiol in heterocyclic synthesis: Synthesis and characterization of several new fused pyridopyrimidine heterocycles

Pyridine-2(1H)-thione 1 reacted with phenyl isothiocyanate to give pyrido[2,3-d]pyrimidine derivative 3. Compound 3 reacted with halogen containing compounds 4a–d and methyl iodide in dimethylformamide/potassium hydroxide solution at room temperature to give 2,7-bisalkylthiopyrido[2,3-b]pyrimidine derivatives 5a–d and 9, respectively. Compounds 5a–d could be cyclized into thienopyrido[2,3-d]pyrimidine derivatives 6a–d by boiling with ethanolic potassium hydroxide solution. Compound 6a reacted with acetic anhydride or formic acid and gave the corresponding pyrimido[4″,5″:4′,5′]thieno[3′,2′:5,6]pyrido[2,3-d]pyrimidine derivatives 8a,b. Compound 9 reacted with hydrazine hydrate to yield pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivative 11 which could be reacted with nitrous acid and dimethylformamide-dimethylacetal (DMF-DMA) and gave the final isolable products corresponding to the pyrazolo[4′,3′:5,6]pyrido[2,3-d]tetrazolo-[5,1-b]pyrimidine and pyrimido[1″,2″:1′,5′]pyrazolo[4′,3′:5,6]pyrido[2,3-d]1 Abbas, A. A., Elneairy, M. A.A. and Mabkhot, Y. N. 2001. J. Chem. Res.(S), 4: 124[Crossref] , [Google Scholar] 2 Riad, B. Y., Negem, A. M., Abdou, S. E. and Daboun, H. A. 1987. Heterocycles, 26: 205[Crossref], [Web of Science ®] , [Google Scholar] 4 Gad-Elkareem, M. A.M. and Abedelhamid, A. O. 2004. Afinidad, 61(513): 427[Web of Science ®] , [Google Scholar]triazolo-[4,3-b] pyrimidine derivatives 13 and 17, respectively. Compound 11 also reacted with some β-dicarbonyl compounds such as acetylacetone (18) and ethyl acetoacetate (20) to yield the corresponding pyrimido[1″,2″:1′,5′]pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives 19 and 21, respectively. Finally, compound 11 reacted with chloroacetyl chloride (22) to give the corresponding imidazo[1″′,2″′:1″,5″]pyrazolo[4″,3″:5′,6′]pyrido[3′,2′:5,6]pyrimido[2,1-c]1 Abbas, A. A., Elneairy, M. A.A. and Mabkhot, Y. N. 2001. J. Chem. Res.(S), 4: 124[Crossref] , [Google Scholar] 2 Riad, B. Y., Negem, A. M., Abdou, S. E. and Daboun, H. A. 1987. Heterocycles, 26: 205[Crossref], [Web of Science ®] , [Google Scholar] 4 Gad-Elkareem, M. A.M. and Abedelhamid, A. O. 2004. Afinidad, 61(513): 427[Web of Science ®] , [Google Scholar]triazine derivative 23.     

Vienna-Type DMA of High Resolution and High Flow Rate

A variant of the Vienna DMA (Winklmayr et al. 1991 Winklmayr, W., Reischl, G. P., Lindner, A. O. and Berner, A. 1991. A New Electromobility Spectrometer for the Measurement of Aerosol Size Distributions in the Size Range From 1 to 1000 nm. J. Aerosol Sci., 22: 289–296. [CROSSREF][CSA][Crossref], [Web of Science ®] , [Google Scholar]; Reischl et al. 1997 Reischl, G. P., Makela, J. M. and Necid, J. 1997. Performance of Vienna Type Differential Mobility Analyzer at 1.2–20 Nanometer. Aerosol Sci. Technol., 27: 651–672. [CSA][Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) with inner and outer electrode radii of 25 and 33 mm, and a conventional trumpet inlet diameter of 97 mm has been tested. It incorporates a reduced pressure drop sheath gas exhaust system that enables reaching flow rates approaching 4000 L/min. Several new additional flow features are included to delay the transition to turbulent conditions. A cylindrical geometry with a DMA length L of 97 mm (distance between the aerosol inlet and outlet slits) is seen to keep the flow laminar up to the highest Reynolds number achieved, though showing slight signs of flow quality deterioration at about Re = 20,000. An equally long DMA with an inner electrode shaped as a 5° cone caped by a spherical dome remains stable up to the highest Reynolds number achieved. It is expected to continue this trend to considerably higher flow rates. Both these long configurations exhibit line widths close to the ideal Brownian diffusion limit, reaching FWHH of 4% for a particle mass diameter of 1 nm. A short DMA with an axial length L of 18 mm and an inner electrode shaped as a 5° cone caped by an ellipse of 3/2 aspect ratio remains also laminar at the highest speeds attained, and exhibits FWHH as small as 2.4%. It departs moderately from ideal behaviour at small flow rates, presumably due to its non-cylindrical geometry. More serious departures observed at high Reynolds numbers may perhaps be due to flow unsteadiness radiated into the working section by sound waves from the turbulent exhaust region. This is the first report of a DMA capable of excellent resolution at 1 nm, yet with a sufficiently wide and long working section to enable (in principle) covering the size range up to 100 nm.     

Numerical Modeling of Nanoparticle Collection Efficiency of Single-Stage Wire-in-Plate Electrostatic Precipitators

The numerical models for predicting the collection efficiency of particles in the size range of 0.3 ～ 10.0 μm in electrostatic precipitators (ESPs) have been well developed. However, for nanoparticles, or particles with the diameter below 100 nm, the existing models can't predict the collection efficiency very well because the electric field and ion concentration distribution were not simulated, or charging models were not adopted appropriately to calculate particle charges. In this study, a 2-D numerical model was developed to predict the nanoparticle collection efficiency in single-stage wire-in-plate ESPs. Laminar flow field was solved by using the Semi-Implicit Method for Pressure-Linked Equation (SIMPLER Method), while electric field strength and ion concentration distribution were solved based on Poisson and diffusion-convection equations, respectively. The charged particle concentration distribution and the particle collection efficiency were then calculated based on the convection-diffusion equation with particle charging calculated by Fuchs diffusion charging theory. The simulated collection efficiencies of 6–100 nm nanoparticles were compared with the experimental data of Huang and Chen (2002 Huang, S. H. and Chen, C. C. 2002. Ultrafine Aerosol Penetration through Electrostatic Precipitators.. Environ. Sci. Technol., 36: 4625–4632. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) for a wire-in-plate dry ESP (aerosol flow rate: 100 L/min, applied voltage: ?15.5 ～ –21.5 kV). Good agreement was obtained. The simulated particle collection efficiencies were further shown to agree with the experimental data obtained in the study for a wire-in-plate wet ESP (Lin et al. 2010 Lin, G. Y., Tsai, C. J., Chen, S. C., Tzu, M. C. and Li, S. N. 2010. An Efficient Single-Stage Wet Electrostatic Precipitator for Fine and Nanosized Particle Control.. Aerosol Sci. Technol, 44: 38–45. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) (aerosol flow rate: 5 L/min, applied voltage: +3.6 ～+4.3 kV) using monodisperse NaCl particles of 10 and 50 nm in diameter. It is expected that the present model can be used to facilitate the design of ESPs for nanoparticle control and electrostatic nanoparticle samplers.     

PENTACYCLIC TRITERPENE CONSTITUENTS OF YELLOW BIRCH BARK FROM QUEBEC*

ABSTRACT

Birch bark represents an abundant, and currently under-utilized, natural resource. Yellow birch (Betula alleghaniensis), the emblem tree of Quebec, is commercially important and one of the most widespread birch species in the province, but the use of its bark is limited. It is only used as a low value fuel source in solid wood products industries. Yellow birch bark triterpene constituents such as lupeol, betulin and betulinic acid have been described to have high biological activity. The yellow birch bark triterpene constituents such as betulin and certain derivatives of this natural substance have demonstrated interesting therapeutic properties. For example, betulinic acid has been shown to possess anti-tumor activity against human melanoma cells both in vitro and in vivo models. Its mechanism of action consists in the induction of apoptosis or cellular suicide in the cancer cells without affecting healthy cells.[14] Pisha, E., Chai, H., Lee, I.-S., Chagwedera, T.E., Farnsworth, N.R., Cordell, G.A., Beecher, C.W.W., Fong, H.H.S., Kinghorn, A.D., Brown, M., Wani, M.C., Wall, M.E., Hieken, T.J., Das Gupta, T.K. and Pezzuto, J.M. 1995. Nature Medicine, 1: 1046[Crossref], [PubMed], [Web of Science ®] , [Google Scholar] These natural products confer added value to this tree. In this study, we investigated the triterpenoid composition of the outer bark of B. alleghaniensis from three locations in Quebec: Saint-Damien de Bellechasse, Saint-Félix-d’Otis, and Duchesnay. Eight triterpenes not previously reported in the bark of yellow birch were detected in this research. The betulonic aldehyde was identified as a new yellow birch bark constituent in bark samples from all sites, while the betulinic aldehyde and the oleanane type triterpenes were only detected in the sample from Saint-Félix-d’Otis. To our knowledge, this is the first time that the oleanane-type triterpenes are identified in yellow birch bark.

     

Numerical Evaluation of the Transfer Function of a Low Pressure DMA by Using the Langevin Dynamic Equation

The effect of Brownian diffusive particle trajectory of nanoparticles on the transfer function of the low pressure Differential Mobility Analyzer (LPDMA) was evaluated by a numerical simulation of the Langevin dynamic equation. The results of the simulation were compared with previously reported experimental results (Seto et al. 1997 Seto, T., Nakamoto, T., Okuyama, K., Adachi, M., Kuga, Y. and Takeuchi, K. 1997. Size Distribution Measurement of Nanometer-Sized Aerosol Particles using DMA under Low-Pressure Conditions. J. Aerosol Sci., 28: 193–206. [CROSSREF][Crossref] , [Google Scholar]; Seol et al. 2000 Seol, K. S., Tsutatani, Y., Camata, R. P., Yabumoto, J., Isomura, S., Okada, Y., Okuyama, K. and Takeuchi, K. 2000. A Differential Mobility Analyzer and A Faraday Cup Electrometer for Operation at 200-930 Pa Pressure. J. Aerosol Sci., 31: 1389–1395. [CSA][CROSSREF][Crossref] , [Google Scholar]) and Stolzenburg's transfer function (1988). As the operational pressure decreased, the peak and FWHM (full width of the transfer function at half of its maximum) values of transfer function, as calculated by numerical simulation, were increased, which was not evident from Stolzenburg's transfer function. In comparison with the experiments of Seto et al., discrepancies in the higher electrical mobility regime than from central mobility were found, which could be caused by the incomplete flow control of their LPDMA. However, the transfer function, as calculated by numerical simulation was in good agreement with experimental results reported by Seol et al., performed with the improved LPDMA at well-controlled operation conditions.     

Field Validation of the New Miniature Versatile Aerosol Concentration Enrichment System (mVACES)

Recently a new compact aerosol concentration enrichment system was developed at the University of Southern California, specifically intended to provide particle-laden air at flow rates and pressures suitable for interfacing with on-line continuous aerosol instrumentation for chemical analysis such as mass spectrometers. The re-design and engineering of the miniature Versatile Aerosol Concentration Enrichment System (mVACES) and primarily laboratory-based validation of the individual components and overall system has been previously reported (Geller et al. 2005 Geller, M. D., Biswas, S., Fine, P. M. and Sioutas, C. 2005. A New Compact Aerosol Concentrator for Use in Conjunction with Low Flow-Rate Continuous Aerosol Instrumentation. J. Aerosol Sci., 36: 1006–1022. [CSA][CROSSREF][Crossref], [Web of Science ®] , [Google Scholar]). From September to December 2005, a field performance validation study of the mVACES was conducted in Los Angeles, California at a mixed urban site influenced by both freeway traffic and construction. A variety of continuous and semi-continuous physical and chemical composition measurements were performed to assess the performance of the mVACES compared to accepted methods for validation. Near-ideal performance for aerosol concentration enhancement by the mVACES was observed for mass and number distribution with minimal evidence for distortion of the size distribution. Similarly, near-ideal concentration enhancement factors were observed for both inorganic and organic species suggesting that the mVACES works equally well across the range of externally mixed urban aerosol. The data suggest that aerosol concentration enhancements up to an ideal factor of 20 in a delivered flow on the order of 1.5 liters min^–1 are readily achievable in an urban environment for the ambient conditions studied.     

A Numerical Study of Calm Air Sampling with a Blunt Sampler

The performance of an idealized spherical sampler facing both vertically upwards and downwards in calm air is studied numerically. To describe the air flow around the sampler, both potential and viscous flow models have been adopted. The equations of particle motion are then solved to calculate the aspiration efficiency. The dependence of the aspiration efficiency upon the various parameters of importance in calm air sampling are investigated and compared where possible with the experimental work of Su and Vincent (2003 Su, W. C. and Vincent, J. H. 2003. Experimental Measurements of Aspiration Efficiency for Idealized Spherical Aerosol Samplers in Calm Air. J. Aerosol Sci., 34: 1151–1165. [CSA][CROSSREF][Crossref], [Web of Science ®] , [Google Scholar], 2004a Su, W. C. and Vincent, J. H. 2004a. Experimental Measurements and Numerical Calculations of Aspiration Efficiency for Cylindrical Thin-Walled Aerosol Samplers in Perfectly Calm Air. Aerosol Sci. Tech., 38: 766–781. [CSA][CROSSREF][Taylor & Francis Online], [Web of Science ®] , [Google Scholar], b Su, W. C. and Vincent, J. H. 2004b. Towards a General Semi-Empirical Model for the Aspiration Efficiencies of Aerosol Samplers in Perfectly Calm Air. J. Aerosol Sci., 35: 1119–1134. [CSA][CROSSREF][Crossref] , [Google Scholar]).

It is found that in the case of upwards sampling the bluntness of the sampler only has a significant effect upon aspiration for large sampling velocities, values that would not generally be physically realistic. In the case of downwards sampling an important non-dimensional quantity, B ² R _C , is identified, where B represents the sampler bluntness and R _C represents the gravitational effects. This quantity determines the physical conditions for which aspiration will not occur and also the limiting values of the aspiration efficiency when aspiration does occur. In the case of low sampling velocities a difference is noted between experimental and numerical results for aspiration efficiency raising the need for more experimental data in this area. For both upwards and downwards sampling the semi-empirical models of Su and Vincent (2004b) Su, W. C. and Vincent, J. H. 2004b. Towards a General Semi-Empirical Model for the Aspiration Efficiencies of Aerosol Samplers in Perfectly Calm Air. J. Aerosol Sci., 35: 1119–1134. [CSA][CROSSREF][Crossref] , [Google Scholar] have been modified to account for the information gained from the study. This is particularly important in the downwards sampling case where the modified model is found to agree particularly well with the results obtained.     

Ionic Liquid-Based Surfactants in Separation Science

A group of nearly forty-eight (48 Pino , V. ; Afonso , A.M. ; Ayala , J.H. ; González , V. ( 2007 ) Micellar solid-phase microextraction for determining partition coefficients of substituted polycyclic aromatic hydrocarbons in micellar media: Possible prediction of hydrocarbon–micelle behavior . Anal. Bioanal. Chem. , 387 ( 6 ): 2271 – 2281 .[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) of surfactants based on ionic liquids (ILs) has been described. The physicochemical and interfacial behavior for several of these IL-based surfactants has been reported since 2004. This review attempts to summarize the important applications that IL-based surfactants have had in analytical chemistry and separation science. Thus, they have been successfully used as extractant systems as substitutes to conventional organic solvents in extraction schemes, or by modifying the chemical structure of conventional extractant sorbents. The analytical performance of these novel IL-based surfactants has been shown to be better than conventional solvents and even better than conventional cationic surfactants. IL-based surfactants have also been used as mobile phase and stationary phase modifiers in high-performance liquid chromatography (HPLC), as modifiers of the electrokinetic chromatographic (EKC) medium, or as the micellar component in capillary electrophoresis (CE). Thus, IL-based surfactant methods constitute a promising and developing area within separation science.     

FORMATION OF BENZYLIC ALCOHOLS AND MESO-ALDEHYDES BY ONE-ELECTRON OXIDATION OF DMBA,A MODEL FOR THE FIRST METABOLIC STEP IN METHYLATED CARCINOGENIC HYDROCARBON ACTIVATION

The hypothesis that hydroxylation of the 7-methyl group is the first step in metabolic activation of 7,12-dimethylbenz[a]anthracene (DMBA) was advanced over three decades ago (1 Flesher, J. W. and Sydnor, K. L. 1971. Carcinogenicity of Derivatives of 7,12-Dimethylbenz[a]anthracene. Cancer Research, 31: 1951–1954. [PubMed], [Web of Science ®] , [Google Scholar], 2 Flesher, J. W. and Sydnor, K. L. 1973. Possible Role of 6-Hydroxymethylbenzo[a]pyrene as a Proximate Carcinogen of Benzo[a]pyrene and 6-Methylbenzo[a]pyrene. Int. J. Cancer, 11: 433–437.  [Google Scholar]). A considerable body of evidence supports the hypothesis (3 Flesher, J. W., Horn, J. and Lehner, A. F. 2002. The Meso-Region Theory of Aromatic Hydrocarbon Carcinogenesis. Polycyclic Aromatic Compounds, 22: 379–393. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). A chemical model for the oxidative metabolism of DMBA may be useful in understanding the mechanism of metabolic activation of DMBA and other methylated carcinogenic hydrocarbons, particularly the first step. Here we show that a nonenzymatic one-electron oxidation pathway transforms DMBA to carcinogenic alcohol and meso-aldehyde metabolites. The results are consistent with the hypothesis that hydroxylation of the 7-methyl and/or 12-methyl groups is the first metabolic step in DMBA activation. The hypothesis predicts that hydroxylation of other meso-methyl-substituted hydrocarbons is the first essential step in the metabolic activation of methylated carcinogenic hydrocarbons.     

Mechanical Effect of Acetic Acid Lignin Adsorption on Honeycomb-Patterned Cellulosic Films

Abstract

We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall.^{[ 1} Nemoto, J., Uraki, Y., Kishimoto, T., Sano, Y., Funada, R., Obata, N., Yabu, H., Tanaka, M. and Shimomura, M. 2005. Production of mesocopically patterned cellulose film. Bioresour. Technol., 96: 1955–1958.  [Google Scholar] ^{, 2} Uraki, Y., Nemoto, J., Otsuka, H., Tamai, Y., Sugiyama, J., Kishimoto, T., Ubukata, M., Yabu, H., Tanaka, M. and Shimomura, M. 2007. Honeycomb-like architecture produced by living bacteria, Gluconacetobacter xylinus. Carbohydr. Polym., 69: 1–6. [Crossref], [Web of Science ®] , [Google Scholar] ^] The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions.     

Indazole,oxathiadiazole, and thiadiazine derivatives from thiosemicarbazides

4-Substituted thiosemicarbazides 1a–c reacted with 2,3-dicyano-5,6-dichloro-1,4-benzoquinone (DDQ, 2), 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL-p, 6) and 2,3-dichloro-1,4-naphthoquinone (DCHNQ, 7) in ethyl acetate with admission of air and form the derivatives of 1,5,2,3-oxathiadiazole 8a–c, indazole 9a–c, 1,3,4-thiadiazine-6-one 10a–c, 1,3,4-thiadiazaphenanthren-9-one 11a–c, naphtho[1,2-e:4,3-è]bis1 Nogami, T., Yoshihara, K. and Nagakura, K. 1972. Bull. Chem. Soc. Jpn., 45: 122[Crossref] , [Google Scholar] 3 Belitskaya, L. D. and Kolesnikov, V. T. 1984. Zh. Org. Khim. (Eng. Translation), 20: 1753 [Google Scholar] 4 Foster, R., Kulevsky, N. and Wanigasekera, D. S. 1974. J. Chem. Soc., Perkin Trans., 1: 1318[Crossref] , [Google Scholar]thiadiazine 12 and dibenzo[b,i]thianthrene-5,7,12,14-tetraone 13. A rationale for the conversions observed is presented.     

Bias in Filter-Based Aerosol Light Absorption Measurements Due to Organic Aerosol Loading: Evidence from Laboratory Measurements

Light absorption by soot or nigrosin dye aerosol particles were measured in the laboratory using a particle soot absorption photometer (PSAP) and a photo-acoustic spectrometer (PAS) to assess the influence of non-absorbing organic aerosol (OA) on the PSAP measurements. For the PSAP, particle light absorption is measured after collection on a filter, whereas for the PAS light absorption is measured while the particles remain suspended in the gas phase. OA was generated from the reaction of α -pinene with ozone. It was observed that the presence of this OA in an external mixture of absorbing aerosol and OA can cause an increase in the light absorption measured by the PSAP, relative to that measured by the PAS, by more than a factor of two. This enhancement in the PSAP absorption was found to increase as the amount of OA increased relative to the absorbing compound. Additionally, experiments where absorbing aerosol was deposited on a PSAP filter prior to addition of OA demonstrated that the non-absorbing OA can actually appear as if it were absorbing, with measured single scattering albedo values as low as 0.92. These results indicate that filter-based measurement techniques may significantly overestimate light absorption by aerosols in the atmosphere under conditions where the organic loading is large, with consequent implications for understanding and calculating the Earth's radiation budget. These laboratory experiments aid in the interpretation of results from a recent field study, discussed in a companion article (Lack et al. 2008 Lack, D. A., Cappa, C. D., Baynard, T., Massoli, P., Covert, D. S., Sierau, B., Bates, T. S., Quinn, P. K., Lovejoy, E. R. and Ravishankara, A. R. 2008. Bias in Filter-Based Aerosol Absorption Measurements Due to Organic Aerosol Loading: Evidence from Ambient Measurements. Aerosol Sci. and Technol., 42: 1033–1041. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]).