Dechlorane plus (DP) in indoor and outdoor air of an urban city in South China: Implications for sources and human inhalation exposure

<p>Dechlorane Plus (DP) is a chemical of emerging concern due to the restrictions on brominated flame retardant formulations. However, very little information is known about the occurrence of DP in indoor and outdoor air and its associated health risk to the exposed human population. In this study, we examined the concentrations and isomer profiles of DP in archived air samples collected from 14 homes, 6 offices, and 10 public microenvironments in Guangzhou, China in 2004–2005. The average (median) value of atmospheric ΣDP (sum of <i>anti-</i>DP and <i>syn-</i>DP) concentration in the three indoor air was 5.73 ± 5.33 (3.62) for offices, 8.08 ± 5.17 (6.87) for homes, and 57.27 ± 83.08 (32.58) pg/m³ for public microenvironments, respectively. ΣDP concentration was significantly higher in the public microenvironments than those in homes and offices. The arithmetic mean and median concentrations of ΣDP in outdoor air were 36.00 and 28.76 pg/m³, respectively. Spatially and temporally consistent indoor and outdoor samples comparison suggested that outdoor air might be a relevant source of DP for indoor air. Average <i>anti</i>-DP fractional abundance (<i>f</i>_anti = 0.65 ± 0.04) in all outdoor samples was similar to those reported in other studies and indistinguishable from that of the commercial mixture (<i>f</i>_anti = 0.65). In contrast, a relatively large variation of <i>f</i>_anti values was found in the indoor samples, suggesting a complex degradation process of DP existing in these microenvironments. The calculated average daily doses of ΣDP were in the range of 0.38–2.21 ng/day for people intake through air inhalation, which was in the same order of magnitude compared with other exposure pathways for the general publics.</p

The Carbamoylmannose Moiety of Bleomycin Mediates Selective Tumor Cell Targeting

Recently, we reported that both bleomycin (BLM) and its disaccharide, conjugated to the cyanine dye Cy5**, bound selectively to cancer cells. Thus, the disaccharide moiety alone recapitulates the tumor cell targeting properties of BLM. Here, we demonstrate that the conjugate of the BLM carbamoylmannose moiety with Cy5** showed tumor cell selective binding and also enhanced cellular uptake in most cancer cell lines. The carbamoyl functionality was required for tumor cell targeting. A dye conjugate prepared from a trivalent cluster of carbamoylmannose exhibited levels of tumor cell binding and internalization significantly greater than those of the simple carbamoylmannose–dye conjugate, consistent with a possible multivalent receptor

Particle-Bound Highly Oxidized Organic Molecules Derived from Aromatic Hydrocarbons in an Urban Atmosphere

Previous laboratory and theoretical studies have demonstrated that gas-phase oxidation of aromatic hydrocarbons can produce highly oxidized organic molecules (HOMs) via autoxidation, yet our molecular-level understanding of aromatics-derived HOMs existing stably in the particulate phase in ambient air remains unclear. In this study, filter-based ambient fine particle samples were collected in the Pearl River Delta region in south China and particle-bound HOMs derived from gas-phase autoxidation of aromatic hydrocarbons were assessed by using a Fourier transform ion cyclotron resonance mass spectrometer. The results revealed that aromatics-derived HOMs that survived in fine particles were more diverse than those observed in the laboratory or predicted by theory. O6–7 class species were the most abundant species (75–90% signal intensity) among the aromatics-derived CHO-HOMs. The aromatics-derived CHON-HOM monomers accounted for 7–10% of all observed CHON species. The observed aromatics-derived CHO- and CHON-HOMs accounted for 1.7–5.1‰ and 0.2–0.6‰, respectively, of the total particulate organic aerosol mass. The semiquantified concentrations of aromatics-derived HOMs were comparable to those of aromatics-derived SOA estimated by the tracer method and increased significantly with relative humidity. The results suggest a substantial contribution of aromatics-derived HOMs in aromatics-derived SOA in an urban atmosphere, particularly during haze days with higher relative humidity

Catalyst-Free Vapor Phase Growth of Ultralong SnSe Single-Crystalline Nanowires

Herein, high quality ultralong tin selenide (SnSe) nanowires (NWs) have been synthesized via physical vapor deposition (PVD) without catalyst. The length of the synthesized SnSe NWs are hundreds of microns and even up to one millimeter, while the mean diameter is about 270 nm, and the aspect ratio of ultralong SnSe NWs can be over 3000. The microstructural characterizations indicate that the SnSe NWs are well-crystallized single crystals with growth direction along the normal {011} planes. The formation of the SnSe NWs is addressed by an oriented one-dimensional growth driven by the dynamic factors in the vapor–solid process. The near-infrared optical band gap of the SnSe NWs has been determined

Aggregation-Induced Emission-Active Near-Infrared Fluorescent Organic Nanoparticles for Noninvasive Long-Term Monitoring of Tumor Growth

Effective long-term monitoring of tumor growth is significant for the evaluation of cancer therapy. Aggregation-induced emission-active near-infrared (NIR) fluorescent organic nanoparticles (<b>TPFE-Rho dots</b>) are designed and synthesized for long-term in vitro cell tracking and in vivo monitoring of tumor growth. <b>TPFE-Rho dots</b> display the advantages of NIR fluorescent emission, large Stokes shift (∼180 nm), good biocompatibility, and high photostability. In vitro cell tracing studies demonstrate that <b>TPFE-Rho dots</b> can track SK-Hep-1 cells over 11 generations. In vivo optical imaging results confirm that <b>TPFE-Rho dots</b> can monitor tumor growth for more than 19 days in a real-time manner. This work indicates that <b>TPFE-Rho dots</b> could act as NIR fluorescent nanoprobes for real-time long-term in situ in vivo monitoring of tumor growth

Soil bulk density, organic carbon content, and organic carbon density of different vegetation type in sand source areas after afforestation of 10 years (mean ±S.E.).

<p> The values within a column of same vegetation type that are followed by the same letter are significantly different at a <0.05.</p

Relationship between carbon densities of typical vegetation and stand age.

<p>Relationship between carbon densities of typical vegetation and stand age.</p

PI3K/Akt Pathway Mediates Nrf2/ARE Activation in Human L02 Hepatocytes Exposed to Low-Concentration HBCDs

We investigated the effects of hexabromocyclododecanes (HBCDs) at environmentally relevant concentrations on human L02 hepatocytes and explored possible underlying molecular mechanism(s), focusing on functional interactions between the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) and nuclear factor-erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathways. The results showed that low concentrations of HBCDs could stimulate cell proliferation in a “DNA-dependent protein kinase catalytic subunit” (DNA-PKcs)-dependent manner, increase protein levels and nuclear translocation of transcription factor Nrf2, and upregulate expression of its target gene heme oxygenase-1 (HO-1). Electrophoretic mobility-shift assays (EMSAs) showed that ARE was a prominent element for HO-1 induction after low-concentration HBCDs exposure. The relationship between PI3K/Akt pathway and Nrf2/HO-1 axis was demonstrated by the finding that pretreatment with PI3K inhibitors (wortmannin, LY294002) attenuated the upregulation of Nrf2 expression induced by HBCDs exposure. Furthermore, knock-down of DNA-PKcs through small interfering RNA blocked Nrf2/HO-1 axis activation in L02 cells exposed to low-concentration HBCDs. Moreover, DNA-PKcs and phosphorylated Akt at Ser⁴⁷³ proved to be crucial in regulating the Nrf2-ARE pathway. Thus, the PI3K/Akt pathway is essential in regulating Nrf2-ARE pathway activation in L02 cells induced by low-concentration HBCDs

The planted tree species in sand source areas of North Beijing, China.

<p>The planted tree species in sand source areas of North Beijing, China.</p

Modified Bleomycin Disaccharides Exhibiting Improved Tumor Cell Targeting

The bleomycins (BLMs) are a family of antitumor antibiotics used clinically for anticancer chemotherapy. Their antitumor selectivity derives at least in part from their ability to target tumor cells, a property that resides in the carbohydrate moiety of the antitumor agent. In earlier studies, we have demonstrated that the tumor cell selectivity resides in the mannose carbamoyl moiety of the BLM saccharide and that both the BLM disaccharide and monosaccharide containing the carbamoyl moiety were capable of the delivery/uptake of a conjugated cyanine dye into cultured cancer cell lines. Presently, the nature of the participation of the carbamoyl moiety has been explored further to provide compounds of utility for defining the nature of the mechanism of tumor cell recognition and uptake by BLM saccharides and in the hope that more efficient compounds could be identified. A library of seven disaccharide–Cy5** dye conjugates was prepared that are structural analogues of the BLM disaccharide. These differed from the natural BLM disaccharide in the position, orientation, and substitution of the carbamoyl group. Studies of these compounds in four matched sets of tumor and normal cell lines revealed a few that were both tumor cell selective and internalized 2–4-fold more efficiently than the natural BLM disaccharide