Naphthalene Research Articles

Identifying structural characteristics of humic acid to static and dynamic fluorescence quenching of phenanthrene, 9-phenanthrol, and naphthalene

Fluorescence quenching is a sensitive and fast method to quantify the interactions between a fluorescent organic contaminant and a quencher, such as dissolved organic matter (DOM). Dynamic fluorescence quenching is resulted from molecular collision, not the real binding, and thus it complicates the binding data interpretation. On the other hand, static fluorescence quenching occurs for fluorescent contaminants of ground states, which decreases the concentration of freely dissolved contaminants. However, how a particular structure in DOM contributes to the static and dynamic fluorescence quenching of a fluorescent contaminant is still unclear, which has greatly hindered the application of fluorescence quenching technique. A humic acid (HA) extracted from sediment was chemically modified, i.e., bleaching, acid hydrolysis, and decarboxylation. HAs before and after these modifications were used in fluorescence quenching experiments for phenanthrene (PHE), 9-phenanthrol (PTR) and naphthalene (NAP). Different quenching mechanisms were observed for these chemicals depending on HA properties. For PHE and NAP, aromatic components showed static quenching, while carboxyl groups primarily showed dynamic quenching. Aromatic components and carbohydrates in HAs primarily bound (static quenching) rather than collided (dynamic quenching) with PTR. Carboxyl groups showed interactions with PTR through dynamic quenching only when carboxyl groups were on the benzene ring. Based on the results, we emphasized that dynamic quenching should be carefully excluded in fluorescence quenching studies. This line of study is important to establish a general relationship between DOM properties and static/dynamic quenching contributions.

Human CYP2A13 and CYP2F1 Mediate Naphthalene Toxicity in the Lung and Nasal Mucosa of CYP2A13/2F1-Humanized Mice.

Background:The potential carcinogenicity of naphthalene (NA), a ubiquitous environmental pollutant, in human respiratory tract is a subject of intense debate. Chief among the uncertainties in risk assessment for NA is whether human lung CYP2A13 and CYP2F1 can mediate NA’s respiratory tract toxicity.Objectives:We aimed to assess the in vivo function of CYP2A13 and CYP2F1 in NA bioactivation and NA-induced respiratory tract toxicity in mouse models.Methods:Rates of microsomal NA bioactivation and the effects of an anti-CYP2A antibody were determined for lung and nasal olfactory mucosa (OM) from Cyp2abfgs-null, CYP2A13-humanized, and CYP2A13/2F1-humanized mice. The extent of NA respiratory toxicity was compared among wild-type, Cyp2abfgs-null, and CYP2A13/2F1-humanized mice following inhalation exposure at an occupationally relevant dose (10 ppm for 4 hr).Results:In vitro studies indicated that the NA bioactivation activities in OM and lung of the CYP2A13/2F1-humanized mice were primarily contributed by, respectively, CYP2A13 and CYP2F1. CYP2A13/2F1-humanized mice showed greater sensitivity to NA than Cyp2abfgs-null mice, with greater depletion of nonprotein sulfhydryl and occurrence of cytotoxicity (observable by routine histology) in the OM, at 2 or 20 hr after termination of NA exposure, in humanized mice. Focal, rather than gross, lung toxicity was observed in Cyp2abfgs-null and CYP2A13/2F1-humanized mice; however, the extent of NA-induced lung injury (shown as volume fraction of damaged cells) was significantly greater in the terminal bronchioles of CYP2A13/2F1-humanized mice than in Cyp2abfgs-null mice.Conclusion:CYP2F1 is an active enzyme. Both CYP2A13 and CYP2F1 are active toward NA in the CYP2A13/2F1-humanized mice, where they play significant roles in NA-induced respiratory tract toxicity. https://doi.org/10.1289/EHP844

Diazonium Salt-Based Surface-Enhanced Raman Spectroscopy Nanosensor: Detection and Quantitation of Aromatic Hydrocarbons in Water Samples.

Here, we present a surface-enhanced Raman spectroscopy (SERS) nanosensor for environmental pollutants detection. This study was conducted on three polycyclic aromatic hydrocarbons (PAHs): benzo[a]pyrene (BaP), fluoranthene (FL), and naphthalene (NAP). SERS substrates were chemically functionalized using 4-dodecyl benzenediazonium-tetrafluoroborate and SERS analyses were conducted to detect the pollutants alone and in mixtures. Compounds were first measured in water-methanol (9:1 volume ratio) samples. Investigation on solutions containing concentrations ranging from 10−6 g L−1 to 10−3 g L−1 provided data to plot calibration curves and to determine the performance of the sensor. The calculated limit of detection (LOD) was 0.026 mg L−1 (10−7 mol L−1) for BaP, 0.064 mg L−1 (3.2 × 10−7 mol L−1) for FL, and 3.94 mg L−1 (3.1 × 10−5 mol L−1) for NAP, respectively. The correlation between the calculated LOD values and the octanol-water partition coefficient (Kow) of the investigated PAHs suggests that the developed nanosensor is particularly suitable for detecting highly non-polar PAH compounds. Measurements conducted on a mixture of the three analytes (i) demonstrated the ability of the developed technology to detect and identify the three analytes in the mixture; (ii) provided the exact quantitation of pollutants in a mixture. Moreover, we optimized the surface regeneration step for the nanosensor.

Impact of hepatic P450-mediated biotransformation on the disposition and respiratory tract toxicity of inhaled naphthalene

We determined whether a decrease in hepatic microsomal cytochrome P450 activity would impact lung toxicity induced by inhalation exposure to naphthalene (NA), a ubiquitous environmental pollutant. The liver-Cpr-null (LCN) mouse showed decreases in microsomal metabolism of NA in liver, but not lung, compared to wild-type (WT) mouse. Plasma levels of NA and NA-glutathione conjugates (NA-GSH) were both higher in LCN than in WT mice after a 4-h nose-only NA inhalation exposure at 10ppm. Levels of NA were also higher in lung and liver of LCN, compared to WT, mice, following exposure to NA at 5 or 10ppm. Despite the large increase in circulating and lung tissue NA levels, the level of NA-GSH, a biomarker of NA bioactivation, was either not different, or only slightly higher, in lung and liver tissues of LCN mice, relative to that in WT mice. Furthermore, the extent of NA-induced acute airway injury, judging from high-resolution lung histopathology and morphometry at 20h following NA exposure, was not higher, but lower, in LCN than in WT mice. These results, while confirming the ability of extrahepatic organ to bioactivate inhaled NA and mediate NA's lung toxicity, suggest that liver P450-generated NA metabolites also have a significant, although relatively small, contribution to airway toxicity of inhaled NA. This hepatic contribution to the airway toxicity of inhaled NA may be an important risk factor for individuals with diminished bioactivation activity in the lung.

Use of selenium to alleviate naphthalene induced oxidative stress in Trifolium repens L

Polycyclic aromatic hydrocarbons (PAHs) are among the most dangerous of environmental contaminants, due to their toxicity, carcinogenicity and mutagenicity. This study investigated the use of selenium (Se) to protect plants from the toxic effects of naphthalene (NPH). Exposing Trifolium repens L. (white clover) to a high concentration of NPH (soil spiked to 500mgkg−1) for 60 d significantly decreased biomass, CO2 assimilation rate (Pn), stomatal conductance (Gs) and intercellular CO2 concentration (Ci), while inducing production of H2O2 and malondialdehyde (MDA). Application of Se (soil spiked to 0.5mgkg−1) to plants exposed to NPH clearly protected the plants; biomass, Pn, Gs and Ci were significantly higher and contents of MDA and H2O2 decreased. The protection provided to Trifolium repens L. by Se is attributed primarily to an increase in photosynthesis and a decrease in oxidative stress. This study demonstrates that a low concentration of Se protects plants against oxidative stress induced by NPH and can provide a means for improving phytoremediation in PAHs contaminated soils.

IL-33/ST2 macrophage crosstalk promotes lung epithelial repair

Abstract Increasing evidence points to a central role for macrophages in tissue regeneration, however, the molecular mechanisms underlying this function remain unknown. Here, using depletion and adoptive transfer approaches, we demonstrate a major role of alveolar macrophages in facilitating bronchial re-epithelialization. In addition, we identify a novel, and paradoxical, protective role for the IL-33/ST2 axis in epithelial repair following naphthalene (NA)-induced lung injury. We defined two subsets of ST2 expressing myeloid cells, namely recruited monocyte-derived cells and resident alternatively activated macrophages (AAMs), which infiltrate the airways during the regeneration of the bronchial epithelium. Further, ST2-deficient mice exhibited an incomplete epithelial repair which was associated with a dysfunctional AAM phenotype and a reduction in the proliferation of a self-renewing subset of Clara progenitor stem cells. Notably, reconstitution of ST2+ AAMs, post NA, completely restored the epithelium in ST2-deficient animals. In contrast, the monocyte/macrophage-dependent CCL2/CCR2 axis was redundant for repair, however, anti ST2-antibody treatment to CCR2−/− mice resulted in ineffective epithelial regeneration and confirmed the observations seen with ST2-deficiency after NA-induced injury. Thus, the IL-33/ST2 pathway regulates effective Clara cell regeneration and bronchial re-epithelialization via AAM polarization and may lead to new therapeutic insights in acute respiratory diseases.

Refinement of protocol for rapid clonal regeneration of economical bamboo, Bambusa balcooa in the agroclimatic conditions of Bihar, India

Bambusa balcooa is a commercially important bamboo. The present study was undertaken for refinement of protocol for the rapid and mass production of this species of bamboo in agroclimatic condition of Bihar. Micro-clonal propagation techniques have been employed for the study. This technique is the only method for the large scale production of B. balcooa. Explants were collected from Bamboo setum from TNB College campus. Combined effect of 6-benzylaminopurine (BAP) and Kinetin (Kn) (BAP 2 mg/l + Kn 0.5 mg/l) resulted in 85% bud breakage during initiation of cultures. One remarkable feature that was observed is that microshoots in medium without supplementation of naphthalene acetic acid (NAA) had necrotic shoots and they had less multiplication rate in liquid media. High multiplication rate with comparatively longer shoots were observed in liquid media. NAA (2.5 mg/l) along with half strength of MS showed 100% rooting but it was less than 50% when Murashige and Skoog (MS) media was supplemented with indole 3-butyric acid (IBA). Remarkably, in half strength of MS, clumps dried at first within 7 days in rooting media, however, new green healthy shoots proliferated later (after 21 days). The data obtained from this study has set a refined protocol for the clonal regeneration of B. balcooa for the state of Bihar. The current study will help to produce this species of bamboo on large scale, and thereby help to boost rural economy of Bihar. Key words: In vitro regeneration, clonal propagation, bamboo, Bambusa balcooa, micropropagation.

Removal efficiency of polycyclic aromatic hydrocarbons and phthalate esters by surface flow wetland in Shunyi district, Beijing

The surface flow wetland (SFW) system was located on Shunyi district, Beijing. It was built to treat industrial wastewater and domestic sewage, which were looked as its influent. Here sixteen polycyclic aromatic hydrocarbons (PAHs) and six phthalate esters (PAEs) were detected by gas chromatography-mass spectrometry (GC-MS).To determine treatment effect of SFW system, concentrations of targeted compounds in the influent were compared with those in the effluent. Results showed typical compounds of industrial wastewater were naphthalene (NAP), phenanthrene (PHE), dibutyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), and their concentrations were ranged from 122.6 ng.L-1 to 760.6 ng.L-1. However typical compounds of domestic sewage were NAP, anthracene (ANT), PHE, DBP, diethyl phthalate (DEP), DEHP, and their concentrations were ranged from 280 ng.L-1 to 7998.1 ng.L-1. Typical compounds of effluent were NAP, PHE, DBP, DEHP, and their concentrations changed between 4.2 ng.L-1 and 1430.74 ng.L-1. The removal rate of those compounds were 10% ~ 99%, and nineteen compounds removal rate reached above 70%.Therefore, it can be concluded that SFW system had a strong effect on the removal of these compounds.

High organic sulfur removal performance of a cobalt based metal-organic framework

Synthesis of a new porous cobalt based metal-organic framework, [Co6(oba)6(CH3O)4(O)2]n·3DMF (TMU-11) has been carried out to introduce a new and highly efficient adsorbent of dibenzothiophene (DBT). This compound has been synthesized by solvothermal method using a nonlinear dicarboxylate ligand and characterized by single-crystal X-ray crystallography. To study the adsorption properties of the synthesized compound, TMU-11, for DBT removal, various factors, such as amount of adsorbent, contact time and temperature were examined. On the basis of the results, maximum efficiency and reusability in DBT removal occur under the mild reaction conditions. Furthermore, the DBT removal follows the pseudo-second order reaction kinetic. The maximum adsorption value is 825mg/g. The selectivity test of DBT over naphthalene (NA) clearly shows that π−π interactions between organic linkers of TMU-11 and the aromatic ring of DBT are not responsible for the adsorption desulfurization (ADS) process and the main part of adsorption takes place on unsaturated site around Co centres. Our findings may provide some insight into the preparation of the adsorbent with superior performance in practical applications.

Crossover from localized to itinerant states in hydrocarbon Mott insulators.

Crossover from an itinerant state to an isolated electronic state in electron-doped polycyclic aromatic hydrocarbon (PAH) was studied for the two smallest zigzag-type molecules of naphthalene (NN) and anthracene (AN) by focusing on their 1 : 1 stoichiometry, A1(NN) and A1(AN), with alkali metals (A = K and Rb). The competition between on-site Coulombic repulsion energy (U) and bandwidth (W) was argued in terms of their magnetic and electrical properties upon lattice expansion, when A varies from K, with a smaller ionic radius, to Rb, with a larger ionic radius. The temperature-dependence of magnetic susceptibility shows a pronounced hump associated with antiferromagnetic (AFM) interactions for Rb1(NN), being similar to those of K1(NN) and K1(AN) in the earlier report. On the other hand, Rb1(AN) intriguingly exhibits paramagnetic susceptibility, observed in a nearly localized electron system, being apart from an highly correlated Mott insulating state. Crystal structural analyses of the X-ray diffraction profiles show a small difference in lattice parameters of the ab plane among K1(NN), K1(AN), and Rb1(NN), whereas Rb1(AN) exhibits a significantly larger value than those of the others, being indicative of greatly modified interaction energies. The different magnetic properties observed in Rb1(AN) are interpreted from its modified intermolecular distance. The possibility of an emergent metallic state of K1(AN) under high pressure has also been described, referring to electrical transport measured under high pressure.

Environmental exposure to polycyclic aromatic hydrocarbons (PAHs): The correlation with and impact on reproductive hormones in umbilical cord serum

Polycyclic aromatic hydrocarbons (PAHs) are a type of ubiquitous pollutant with the potential ability to cause endocrine disruption that would have an adverse health impact on the general population. To assess the maternal exposure to PAHs in neonates and evaluate the possible impact of PAHs on reproductive hormone levels, the concentration of PAHs and reproductive hormone levels in the umbilical cord serum of 98 mother-infant pairs in the Shengsi Islands were investigated. The median concentration of total PAHs was determined to be 164 (Inter-Quartile Range, IQR 93.6–267) ng g−1 lipid, and 68% of the PAHs were lower-molecule congeners. The highest level was found for pyrene (PYR) and naphthalene (NAP), which contributed 54.6% of all the PAHs present in the samples. The exposure to PAHs negatively affected estradiol (E2) and Anti-Mullerian hormones (AMH) and positively affected FSH in the umbilical cord serum. The result expanded the database of the human burden of PAHs and suggested that PAHs can act as a type of Endocrine-Disrupting Chemical (EDC). These results may help to understand the complex pathways involved in disorders of human reproductive health associated with prenatal exposure to PAHs.

Effect of Polyaryl Hydrocarbons on Cytotoxicity in Monocytic Cells: Potential Role of Cytochromes P450 and Oxidative Stress Pathways.

BackgroundBenzo(a)pyrene (BaP), naphthalene (NPh), phenanthrene (Phe), benzo(a)antharacene (BeA), and benzo(b)fluoranthene (BeF) are known carcinogenic polyaryl hydrocarbons (PAHs) present in cigarette smoke. This study was designed to examine the relative effect of these constituents on the cytotoxicity of monocytic cells and the possible mechanism of PAH-mediated cytotoxicity.MethodsWe examined the acute (6–24 hours) and chronic (7 days) effects of these PAHs on the expression of cytochromes P450 (CYPs), oxidative stress, and cytotoxicity. The treated cells were examined for mRNA and protein levels of CYPs (1A1 and 3A4) and antioxidants enzymes (AOEs) superoxide dismutase-1 (SOD1) and catalase. Further, we assessed the levels of reactive oxygen species (ROS), caspase-3 cleavage activity, and cell viability. We performed these experiments in U937 and/or primary monocytic cells.ResultsOf the five PAHs tested, after chronic treatment only BaP (100 nM) showed a significant increase in the expression of CYP1A1, AOEs (SOD1 and catalase), ROS generation, caspase-3 cleavage activity, and cytotoxicity. However, acute treatment with BaP showed only an increase in the mRNA expression of CYP1A1.ConclusionsThese results suggest that of the five PAHs tested, BaP is the major contributor to the toxic effect of PAHs in monocytic cells, which is likely to occur through CYP and oxidative stress pathways.

Estimating population exposure to ambient polycyclic aromatic hydrocarbon in the United States – Part II: Source apportionment and cancer risk assessment

A revised Community Multiscale Air Quality (CMAQ) model was developed to simulate the emission, reactions, transport, deposition and gas-to-particle partitioning processes of 16 priority polycyclic aromatic hydrocarbons (PAHs), as described in Part I of the two-part series. The updated CMAQ model was applied in this study to quantify the contributions of different emission sources to the predicted PAH concentrations and excess cancer risk in the United States (US) in 2011. The cancer risk in the continental US due to inhalation exposure of outdoor naphthalene (NAPH) and seven larger carcinogenic PAHs (cPAHs) was predicted to be significant. The incremental lifetime cancer risk (ILCR) exceeds 1×10−5 in many urban and industrial areas. Exposure to PAHs was estimated to result in 5704 (608–10,800) excess lifetime cancer cases. Point sources not related with energy generation and the oil and gas processes account for approximately 31% of the excess cancer cases, followed by non-road engines with 18.6% contributions. Contributions of residential wood combustion (16.2%) are similar to that of transportation-related sources (mostly motor vehicles with small contributions from railway and marine vessels; 13.4%). The oil and gas industry emissions, although large contributors to high concentrations of cPAHs regionally, are only responsible of 4.3% of the excess cancer cases, which is similar to the contributions of non-US sources (6.8%) and non-point sources (7.2%). The power generation units pose the most minimal impact on excess cancer risk, with contributions of approximately 2.3%.

Comparative Genomics and Metabolic Analysis Reveals Peculiar Characteristics of Rhodococcus opacus Strain M213 Particularly for Naphthalene Degradation.

The genome of Rhodococcus opacus strain M213, isolated from a fuel-oil contaminated soil, was sequenced and annotated which revealed a genome size of 9,194,165 bp encoding 8680 putative genes and a G+C content of 66.72%. Among the protein coding genes, 71.77% were annotated as clusters of orthologous groups of proteins (COGs); 55% of the COGs were present as paralog clusters. Pulsed field gel electrophoresis (PFGE) analysis of M213 revealed the presence of three different sized replicons- a circular chromosome and two megaplasmids (pNUO1 and pNUO2) estimated to be of 750Kb 350Kb in size, respectively. Conversely, using an alternative approach of optical mapping, the plasmid replicons appeared as a circular ~1.2 Mb megaplasmid and a linear, ~0.7 Mb megaplasmid. Genome-wide comparative analysis of M213 with a cohort of sequenced Rhodococcus species revealed low syntenic affiliation with other R. opacus species including strains B4 and PD630. Conversely, a closer affiliation of M213, at the functional (COG) level, was observed with the catabolically versatile R. jostii strain RHA1 and other Rhodococcii such as R. wratislaviensis strain IFP 2016, R. imtechensis strain RKJ300, Rhodococcus sp. strain JVH1, and Rhodococcus sp. strain DK17, respectively. An in-depth, genome-wide comparison between these functional relatives revealed 971 unique genes in M213 representing 11% of its total genome; many associating with catabolic functions. Of major interest was the identification of as many as 154 genomic islands (GEIs), many with duplicated catabolic genes, in particular for PAHs; a trait that was confirmed by PCR-based identification of naphthalene dioxygenase (NDO) as a representative gene, across PFGE-resolved replicons of strain M213. Interestingly, several plasmid/GEI-encoded genes, that likely participate in degrading naphthalene (NAP) via a peculiar pathway, were also identified in strain M213 using a combination of bioinformatics, metabolic analysis and gene expression measurements of selected catabolic genes by RT-PCR. Taken together, this study provides a comprehensive understanding of the genome plasticity and ecological competitiveness of strain M213 likely facilitated by horizontal gene transfer (HGT), bacteriophage attacks and genomic reshuffling- aspects that continue to be understudied and thus poorly understood, in particular for the soil-borne Rhodococcii.

Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria.

Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp.) and P3 (Pseudomonas sp.), which degraded more than 90% of phenanthrene (PHE) within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP), PHE, fluorene (FLR), pyrene (PYR), and benzo(a)pyrene (B(a)P) as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(a)P, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(a)P. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days). Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

CORRELATION OF MOLECULAR MOTIFS AND NON-CLASSICAL-HYDROGEN-BONDING INTERACTIONS IN CRYSTAL OF 2,7-DIMETHOXY-3-(1-NAPHTHOYL)NAPHTHALENE

The crystal structure is reported for 2,7-dimethoxy-3-(1-naphthoyl)naphthalene ( 1 ), C 23 H 17 O 3 , one of b -aroylated naphthalene compounds. In crystal, two naphthalene ring moieties of respective molecules are non-coplanarly located to each other, and two molecules are nested inside one another through a pair of C–H···π hydrogen-bonding interactions (C–H··· Cg = 2.73 A) forming a dimeric molecular aggregate. Each dimeric molecular aggregate is linked with four adjacent dimers by regular-squarely directed four (sp 3 )C–H···OCH 3 hydrogen bonds between the methoxy groups (C–H···O = 2.50 A) forming two-dimensionally spread plane. The planes are stacked into piles of layers along ac diagonal. On the other hand, the b -aroylated naphthalene homologues, 3-benzoylated naphthalene derivative I and 3-(2-naphthoylated) one II , are proved to take unidimensional molecular accumulation. Though each dimeric molecular aggregate has four identical interactions between adjacent dimeric molecular aggregates in crystal of homologue I , the rectangular, i.e. , non-regular-square aligned situation of four interactions makes the linkage of each aggregate with only two adjacent dimers resulting in ribbon structure. In crystal of homologue II , molecules are stacked without formation of dimeric aggregates in columnar structure. On the basis of the results of systematic comparison of molecular packing structure and effective noncovalent-bonding interactions among title compound 1 and the b -aroylated naphthalene homologues I and II , the presence of large difference in strength of intermolecular interactions, i.e. , predominant or apparently sole functioning of either C–H···O hydrogen bond or C–H···π hydrogen-bonding interaction induces only unidimensional molecular accumulation, e.g. , ribbon-like alignment composed of dimeric molecular aggregates or columnar assembling of molecules. 1 H NMR spectra suggest that conformational interconversion behaviour of title compound 1 through rotation around two kinds of C–C bonds in solution is disturbed rather largely compared to two homologous compounds I and II . Spatial organization characteristics of single molecular and molecular packing structures of b -aroylated naphthalene homologues in crystal are comparatively analyzed along with those in solution for the sake of elucidation of relationship among spatial organization, noncovalent bonding intermolecular interaction in crystal, and steric factors in solution.

Production of artemisinin in shoot cultures of Artemisia cina irradiated callus

Artemisinin is an antimalaria agent that is only found in Artemisia sp . medicinal plant. This compound is occurred at very low level in that plant. Irradiated callus of Artemisia cina have been conducted by the dose of 40 Gy to improve artemisinin content in shoot cultures. Regeneration of irradiated callus to shoot cultures formation has been successful in Murashige & Skoog (MS) medium combined with Naphtalene Acetic Acid (NAA) 1 mg/g, Benzyl Amino Purin (BAP) 2 mg/L and 15 % coconut water. Ten mutant lines of shoot cultures have been analyzed for the artemisinin content. The artemisinin content of mutant lines were higher than the original plant. The highest artemisinin content is 5 mg/g found in mutant line number 404, this line also has wider leaf area than original plant. Key word : artemisinin, Artemisia cina , shoot cultures, irradiated callus

Enhancement Effect of Fused Double Benzene-Ring Structure on the Light Output of Carborane-Loaded Toluene- and Pseudocumene-Based Scintillators

Four sample groups were prepared by adding different concentrations of naphthalene (NP) or of 2,6-diisopropylnaphthalene (DIN) as a secondary solvent ( ${{\rm S}_2}$ ) in carborane-loaded toluene (TL)- and pseudocumene (PC)-based scintillators. The pulse-height spectra of the samples in response to $^{137}{\rm Cs} \gamma $ -rays and to thermal neutrons were collected to study the light output ( $L$ ) enhancement effect of ${{\rm S}_2}$ . It is found that for all sample groups, $L$ increases to a plateau with the concentration of secondary solvent ([ ${{\rm S}_2}$ ]). As [ ${{\rm S}_2}$ ] is increased from 0 to saturation concentration, $L$ increases by 31–45% and 34–53% in response to $^{137}{\rm Cs} \gamma $ -rays and to thermal neurons, respectively. A first-order approximation model is proposed to fit to the experimental data. The enhancement factor ( ${k_h}$ ) and maximum $L$ of each sample group are obtained from curve fitting. The Birks factor ( kB ) and electron equivalent energy ( keVee ) of each sample are calculated by a numerical method based on Birks formula. The $L$ enhancement is discussed according to the percent changes of these parameters. In conclusion, the enhancement effect is attributed mainly to the fused double benzene-ring structure of NP and DIN, which has more delocalized electrons, and provides faster Forster resonance energy transfer paths than the single benzene-ring structure of TL and PC. Adding NP or DIN leads to a significant increase in absolute scintillation efficiency $(S)$ and a slight decrease in kB for both scintillators. It is believed that DIN has slightly larger enhancement effect than NP. A so-called “dynamic quenching” is confirmed to exist in the scintillation process based on the ${k_h}$ values in response to $^{137}{\rm Cs} \gamma $ -rays and to thermal neutrons.

Combining an epithelial repair factor and anti-fibrotic with a corticosteroid offers optimal treatment for allergic airways disease.

We evaluated the extent to which individual versus combination treatments that specifically target airway epithelial damage [trefoil factor-2 (TFF2)], airway fibrosis [serelaxin (RLX)] or airway inflammation [dexamethasone (DEX)] reversed the pathogenesis of chronic allergic airways disease (AAD). Following induction of ovalbumin (OVA)-induced chronic AAD in 6–8 week female Balb/c mice, animals were i.p. administered naphthalene (NA) on day 64 to induce epithelial damage, then received daily intranasal administration of RLX (0.8 mg·mL(−1)), TFF2 (0.5 mg·mL(−1)), DEX (0.5 mg·mL(−1)), RLX + TFF2 or RLX + TFF2 + DEX from days 67–74. On day 75, lung function was assessed by invasive plethysmography, before lung tissue was isolated for analyses of various measures. The control group was treated with saline + corn oil (vehicle for NA). OVA + NA-injured mice demonstrated significantly increased airway inflammation, airway remodelling (AWR) (epithelial damage/thickness; subepithelial myofibroblast differentiation, extracellular matrix accumulation and fibronectin deposition; total lung collagen concentration), and significantly reduced airway dynamic compliance (cDyn). RLX + TFF2 markedly reversed several measures of OVA + NA-induced AWR and normalized the reduction in cDyn. The combined effects of RLX + TFF2 + DEX significantly reversed peribronchial inflammation score, airway epithelial damage, subepithelial extracellular matrix accumulation/fibronectin deposition and total lung collagen concentration (by 50–90%) and also normalized the reduction of cDyn. Combining an epithelial repair factor and anti-fibrotic provides an effective means of treating the AWR and dysfunction associated with AAD/asthma and may act as an effective adjunct therapy to anti-inflammatory corticosteroids

Lanthanide oxide modified H-Mordenites: Deactivation of external acid sites in the isopropylation of naphthalene

The external surface of the H-Mordenite (MOR) was modified with lanthanide oxides such as CeO2, La2O3, Pr2O3, Sm2O3, Dy2O3, and Yb2O3, to investigate the deactivation of external acid sites. It is confirmed that the modification with the oxides prevents the isomerization of 2,6-diisopropylnaphthalene (DIPN) during the isopropylation of naphthalene (NP). The oxides accumulated on the MOR surface deactivated the acid sites with keeping catalytic activities of the isopropylation when their loadings are in the range of 5–10 wt%; however, the differences in the activities were observed when the loading was increased to 20–30 wt%: CeO2 gave a high activity with a high selectivity for 2,6-DIPN, and Sm2O3 maintained moderate activities, whereas the other oxides lost the activities. The differences of the modified MORs are ascribed to the morphologies of mesopores formed by the accumulation of the oxides. CeO2 is accumulated as segregated nano-sized crystallites, and the pore-entrances of MOR are opened through their mesopores for the access of NP and its products, and the isopropylation occurs in the channels with a high selectivity for 2,6-DIPN without a significant loss of the activities. However, La2O3 is accumulated as amorphous glassy oxide with a low surface area, leading to the loss of the activities by disturbing the access of NP to MOR pores. Further, amorphous glassy Sm2O3 also supports the selective formation of 2,6-DIPN as the mesopores allow the access of NP to MOR channels.