共查询到20条相似文献,搜索用时 46 毫秒
1.
《Journal of Sulfur Chemistry》2013,34(4-5):381-391
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 2 4triazolo-[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 2 4triazine derivative 23. 相似文献
2.
Yasumitsu Uraki Chinatsu Matsumoto Takuro Hirai Yutaka Tamai Makiko Enoki Hiroshi Yabu 《木材化学与工艺学杂志》2013,33(4):348-359
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 , 2 ] 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. 相似文献
3.
Kristian Dreij Edyta Bajak Kathrin Sundberg Ian Cotgreave Bengt Jernström Albrecht Seidel 《Polycyclic Aromatic Compounds》2013,33(4-5):549-566
The fjord-region PAH dibenzo[a,l]pyrene (DBP) is considerably more carcinogenic than the bay-region benzo[a]pyrene (BP). This fact can be ascribed to differences in DNA binding efficiency of their ultimate carcinogenic diol epoxide (DEs) intermediates, differences in structural features of the DNA adducts, and differences in DNA adduct recognition and the subsequent lesion removal by nucleotide excision repair (NER). In order to further substantiate previous findings in cell-free human systems (1), cultured cells (2), and in rodents (3) we have studied DNA adduct formation of anti-DE of DBP [(±)-anti-DBPDE], in A549 human epithelial lung carcinoma cells and monitored the levels of adducts as a function of time. A high-performance liquid chromatography (HPLC) procedure that allows monitoring of all cis- and trans-nucleoside adducts of dA and dG was used. Circular dichroism and UV-spectroscopy have been employed to gain information on adduct structural features. Incubation of cells with 0.1 μM (±)-anti-DBPDE resulted in rapid formation of adducts, followed by a decline. After 6 h of incubation about 20% of the adducts remained. Repeating the experiment with 0.01 μM (±)-anti-DBPDE resulted in a correspondingly lower adduct level initially, but in this case a larger proportion (35%) of the adducts remained after 6 h of incubation. Notably, at this time point, similar amounts of adducts are observed with both (±)-anti-DBPDE concentrations studied. Independent of diol epoxide concentration and incubation time, the dA/dG adducts were constant in number (~2.8). However, within the different adduct categories, the adduct distribution seemed to be time dependent. Although the data are preliminary, a selection with regard to adduct removal seems to have taken place. In comparative experiments with (+)-anti-BPDE, no significant difference in rates of adduct removal was evident. Preliminary results from global gene expression analysis, with focus on genes involved in DNA maintenance and cell cycle checkpoints, demonstrate interesting differences in the stress response elicited in the cells following exposure to the distorted and flexible nonplanar DBPDE or the rigid and planar BPDE molecule. As expected some major common induction events were clearly related to the activation of p53-dependent cell cycle checkpoint. However, distinct clusters of gene expression alterations were detected which mark one or other treatment specifically, indicating a high degree of subtlety in the stress response to closely related DNA adduct forming species. 相似文献
4.
Y. Kondo L. Sahu N. Moteki F. Khan N. Takegawa X. Liu 《Aerosol science and technology》2013,47(2):295-312
In this study, we show that black carbon (BC) mass concentrations measured by different techniques are consistent and traceable. First, we present the volatilities of 13 organic compounds passed through a heated inlet. These data were used to quantify the interference of organic aerosols on the BC measurement techniques. The masses of the refractory particles that incandesce (m*ref) were used to calibrate BC mass measured by a single-particle soot photometer (SP2), which uses laser-induced incandescence. This calibration was influenced little by refractory organics and agreed well with that of fullerene soot, which indicates the consistency of the standards. We estimated the interference of pyrolyzed refractory organics on the BC measured with a filter-based absorption photometer continuous soot monitoring system (COSMOS) with a heated inlet to be small in Asia. This was also confirmed by the stable mass absorption cross section (MAC) obtained by the high correlations between BC mass concentrations measured by COSMOS (M COSMOS) and those measured by the thermal-optical transmittance method (M TOT) (Kondo et al. 2009). M COSMOS was also compared with total BC mass concentrations measured with an SP2 (M SP2) in Tokyo in 2009. M COSMOS and M SP2 were highly correlated (r 2= 0.97) and agreed to within about 10% on average. These results demonstrate that M SP2, M COSMOS, and M TOT were nearly identical. Use of the masses of incandescing refractory BC particles for calibration of BC mass concentrations determined by different techniques gave consistent results. 相似文献
5.
Dong Keun Song Hyuksang Chang Sang Soo Kim Kikuo Okuyama 《Aerosol science and technology》2013,47(8):701-712
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; Seol et al. 2000) 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. 相似文献
6.
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), N-(4-chloro-benzylidene)4-methyl-benzene-sulfonamide (2), and N- (4-methoxybenzylidene)-4-methyl-benzene sulfonamide (3), and acetophenone (4) and its three derivatives, 4-chloroacetophenone (5), 4-nitro-acetophenone (6), and 4-methoxyaceto -phenone (7). 1D-DOSY was applied to a mixture of compounds (1), (2), and (3) and to a mixture of compounds (4), (5), (6), and (7). 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. 相似文献
7.
Daryl L. Roberts 《Aerosol science and technology》2013,47(11):1119-1129
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), 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, b; 2004), 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. 相似文献
8.
Simulations of the sky dome color shifts of a cloudless sky have been performed, assuming three urban-industrial tropospheric aerosol cases. Each of these aerosols is represented by the bimodal lognormal volume distribution (Dubovik et al. 2002). A total of ten parameters are used to control the aerosol characteristics. These ten parameters are perturbed and the resulting sky color shifts are estimated. All simulations have been performed relative to the reference cases that represent the time-averaged state of each aerosol case. We have simulated the sensitivity of the theoretical CIE (Commission Internationale de l′ Eclairage) standard human observer to discriminate sky color changes, due to changes of the aerosol control parameters. A Digital color Camera Model (DCM) has also been incorporated in the simulation scheme. The DCM simulates the performance of a camera-colorimeter created specifically to measure sky color. The DCM has been used to investigate whether a color digital camera can replicate the behavior of the CIE standard observer, with respect to sky color shifts. The standard observer is most sensitive to perturbations of the parameters of the aerosol fine mode, which are particles with diameters less than 0.6 μ m. However his sensitivity is highly variable, depending on the parameter varied, on the aerosol case and on the direction of the observation. The DCM was in excellent agreement with the behavior of the CIE standard observer. The camera simulated sky color measurement accuracy was high. The results show that the camera sensitivity in discriminating color differences is much better than that of the observer. 相似文献
9.
Ronald G. Harvey Qing Dai Chongzhao Ran Keunpoong Lim Ian Blair Trevor M. Penning 《Polycyclic Aromatic Compounds》2013,33(5):371-391
Syntheses are reported for: (1) adducts of the quinone metabolites of benzo[a]pyrene (BPQ) and benz[a]anthracene (BAQ) with 2′-deoxyadenosine and 2′-deoxyguanosine; (2) 15 N-labelled analogs of these adducts (four or five nitrogen atoms 15 N-labelled); (3) depurinated adducts of BPQ and BAQ with adenine or guanine covalently linked to the N7 or N9 positions of the purine bases; (4) 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) 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. 相似文献
10.
《Journal of Sulfur Chemistry》2013,34(5):549-558
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 3thiazolidine-2,2′ -1 3 4thiadiazole derivatives 8a–f. The antibacterial activity of the novel 1, 3-thiazolidine-2,2′ -spiro- 1 3 4thiadiazole 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. 相似文献
11.
Christopher D. Cappa Daniel A. Lack James B. Burkholder A. R. Ravishankara 《Aerosol science and technology》2013,47(12):1022-1032
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). 相似文献
12.
Three primary benefits (advantages) of properly designed and operated ozone laundering systems have been proven in successful commercial installations – microbiological kills/inactivation of all microorganisms found in linens to be laundered; economic cost savings and significant environmental benefits. Each of these benefits of ozone laundering is described and quantified in the Ozone Laundry Handbook by Rice et al. (2009). In this paper, two of these benefits, Cost Savings and Significant Environmental Benefits are discussed. 相似文献
13.
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), 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), 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) 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 相似文献
14.
S. B. Kwon T. Fujimoto Y. Kuga H. Sakurai T. Seto 《Aerosol science and technology》2013,47(10):987-1001
The surface discharge on a dielectric barrier induced by dc pulses was successfully utilized as a stable bipolar ion source for neutralizing submicron aerosol particles where the concentration of positive and negative ions could be adjusted independently (a surface-discharge microplasma aerosol charger: SMAC; Kwon et al., 2005). The aim of this study was to determine the charge distribution obtained by the SMAC, which has been qualitatively presented in our previous study, and to investigate the effect of unequal bipolar ion concentration on the charge distribution. For this purpose, we performed quantitative analysis of the charge distribution of monodisperse particles in the size range of 30–200 nm acquired by the SMAC and compared the charge distributions with calculated charge fractions obtained from the diffusion charging theory. The ion parameters were calculated by measuring the ion mobility of positive and negative ions and they were used to obtain the analytic solutions of charge distribution. The charge distributions obtained by the equal or unequal concentration of bipolar ions adjusted by the SMAC showed general agreement with the diffusion charging theory. 相似文献
15.
Ming Zhou Noshir Pesika Hongbo Zeng Jin Wan Yonggang Meng 《The Journal of Adhesion》2013,89(11):1045-1058
According to the peel zone model proposed by Pesika et al. [8], the peel strength of an adhesive tape is proportional to the length of the peel zone or the bifurcation region at the peeling front between the tape backing and the substrate. In this study, the effects of the peel angle and peel velocity on the shape of the peel zone and the peel strength are further investigated theoretically and experimentally. The theoretical analysis on the angle at the edge of the peel zone, θ0, and the peel strengths at different peel velocities and angles was compared with experimental tests using three different commercial tapes. The experimental results are in good agreement with the extended peel zone model, which provides a simple approach to predict the peel strength of adhesive tapes with different physical properties at different peel angles and velocities. 相似文献
16.
Matt Frain David P. Schmidt Yong-Le Pan Richard K. Chang 《Aerosol science and technology》2013,47(3):218-225
Pulsed airflow cued by the fluorescence spectrum of a particular aerosol can be used to distinguish and deflect particles of biological origin out of an aerosol stream, permitting concentration of these particles for subsequent analysis (Pan et al. 2004). However, these high velocity pulses of air have an inherent tendency to scatter particles, confounding efforts to concentrate these deflected particles for analysis. The ability to concentrate large numbers of biological particles into a small area on a collection substrate is particularly important for more species-specific techniques such as Raman and FTIR (Fourier Transform Infra-Red) spectroscopy, which require long integration times due to their weak signal strength. In the present work, a simple method is developed for deflecting and localizing particles after classification by a pulsed airflow. The concept is both modeled and experimentally tested. A specially designed funnel is used to localize the scattered particles onto an area of substrate as small as 1 mm in diameter. Computational fluid dynamics simulations were performed to investigate the interaction of the pulsed airflow with the deflected particles and the localizing funnel, in order to gain insight into design parameters and operating conditions that affect the efficiency of this technique. The results show that the combination of pulsed airflow with a localizing funnel effectively deflects and localizes the concentrated bioaerosol onto a small area of substrate or an opening of a microfluidic cell. 相似文献
17.
Over the past two decades, significant efforts have been expended to identify the photochemical decomposition products of the OH radical reactions of various polycyclic aromatic compounds (PAC), such as naphthalene, methylnaphthalenes, acenaphthene and phenanthrene (1, 2, 3, 4, 5, 6, 7). Although these parent PAC are predominantly found in the gas phase, many of their oxidation products have been found largely in the particle phase (4, 7, 8). These products include diones, hydroxy-, and nitrated products as well as many products resulting from ring-opening steps. It is, or should be, the goal of every laboratory study on atmospheric processes to apply the laboratory results to real world samples. To this end, we have obtained particulate matter air samples, as well as some smog episode samples, from Seoul Korea and have searched for the known decomposition products of the above mentioned PAC. To eliminate the use of chlorinated solvents used in the extraction and analysis of particulate matter samples, we have been utilizing the direct thermal desorption of small (4 mm diameter) punches of filters followed by Multidimensional Gas Chromatography-Time of Flight Mass Spectrometry (TD-GCxGC-TOFMS) for the analysis of the desorbed compounds. So far, we have detected 14 of the known decomposition products of naphthalene, acenaphthene and phenanthrene in the Seoul pollution episode samples. These include: 1-hydroxynaphthalene, (E) 2-formylcinnamaldehyde, phthalic anhydride, phthalide, 1,2-naphthalic anhydride, 9-hydroxyphenanthrene and dibenzopyrone. 相似文献
18.
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, 2). A considerable body of evidence supports the hypothesis (3). 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. 相似文献
19.
《Journal of Sulfur Chemistry》2013,34(2):211-222
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 3 4thiadiazine 12 and dibenzo[b,i]thianthrene-5,7,12,14-tetraone 13. A rationale for the conversions observed is presented. 相似文献
20.
An aerosol dynamics model for dry deposition process is developed based on the moment method. Since it is hard to fully apply the moment method to the widely used dry deposition velocity expressions based on the resistance theory, the dry deposition velocity expression by Raupach et al. (2001) is used. Detailed deposition mechanisms such as Brownian diffusion, gravitational settling, and impaction are considered in the expression. To verify the validity of the derived dynamic equation, aerosol dynamics for the dry deposition process is estimated with the expressions of Raupach et al. (2001), of Wesely (1989) modified for particles (Seinfeld and Pandis 1998), in CMAQ, and with constant value used in RAINS-ASIA. Those expressions give different dynamics. Generally, the result for this study is between the result of modified Wesely's expression and CMAQ. When using the modified Wesely's expression with the number of sections being equal or smaller than 10, the resultant size distribution does not give the peak shape accurately. 相似文献