Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and ...uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 “Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile”.
Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz
a
anthracene (BaA), benzo
a
pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %.
Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pK
ow
< −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography.
KEY WORDS FOR SEARCH
benz
a
anthracene (BaA), benzo
a
pyrene (BaP), gas chromatography(GC), isotope dilution (ID), liquid chromatography (LC), mass spectrometry (MS), naphthalene (Nap), organic calibration solution, polycyclic aromatic hydrocarbon (PAH)
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The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
An all-polymer fiber polarizer is proposed for terahertz applications. The polarizer is based on a mechanism which makes use of subwavelength fibers and absorption films. Several centimeters of the ...film could give an extinction ratio of 30 dB, while keeping the insertion loss below 4 dB. Experiments have been conducted to verify the mechanism and distinct polarization-dependent absorptions have been obtained.
Abstract
Nasopharyngeal carcinoma (NPC) is an aggressive epithelial malignancy that has remarkably high incidence and mortality rates in Hong Kong and south China. It is well-known to be associated ...with Epstein-Barr virus (EBV) infection. Previous work in our team revealed that EBV-encoded miRNAs derived from the BARTs (miR-BARTs) were abundantly expressed in primary NPCs. They function in controlling apoptotic and immune responses in the infected cells during NPC development.
Most recently, we attempted to use in silico method to predict cellular targets of miR-BARTs. Results suggested that there were multiple putative miR-BART binding sites on the 3’UTRs of an important DNA double-strand breaks (DSBs) repair gene, Ataxia-Telangiectasia-Mutant (ATM). The down-regulation of ATM mRNA and protein had also been demonstrated in our local primary NPC samples. Although the interaction of miR-BARTs on each suggested putative binding site had not been completely validated, our preliminary data indicated at least three EBV-encoded miRNAs (BART5-5p, BART9-3p and BART14-3p) were involved in repressing ATM expression in NPCs. They could work either alone or cooperatively to control ATM expression in transient assays. Notably, ectopic expression of these three miR-BARTs could successfully suppress γ irradiation-induced ATM activity in two EBV-negative cell lines, NP69 and HeLa.
It had been reported that ATM null cells were defective to repair the DSB lesions and sensitive to the Poly(ADP-ribose) polymerase (PARP) inhibitor treatment in the presence of DNA-damaging agents. In contrast, the DSBs are effectively repaired in normal cells to retain genetic integrity. We believed that EBV infection, via miR-BARTs to reduce ATM activity and disrupt Homologous Recombination (HR) repair function, made the NPC cells sensitize to ionizing radiation and DNA-damaging agent treatment. Hence, the knowledge generated from this project is not only enhance our understanding of EBV biology, but also opens an avenue for the development of effective NPC therapies.
Citation Format: RAYMOND Wai-Ming LUNG, Tom Pok-Man Hau, Wing-Po Chak, Joanna Hung-Man Tong, Ken Hung-On Yu, Sai-Wah Tsao, Kevin Yuk-Lap Yip, Ka-Fai To, Kwok-Wai Lo. The role of Epstein-Barr virus-encoded miRNAs in ATM regulating DNA damage response in nasopharyngeal carcinoma. abstract. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1118.
Recently, we have demonstrated that silymarin has a comparable pharmaceutical activity as Phyllanthus urinaria extract when used to rescue mice from acetaminophen-induced acute liver injury. In the ...present study, we further compared the therapeutic action of silymarin with N-acetyl cysteine (commonly used in clinical practice for emergency treatments) as a rescuer in mice after administering a lethal dose of acetaminophen for 24 h.
Acute liver injury was induced in the treatment groups by intraperitoneally administered acetaminophen at a dose of 550 mg/kg body weight on day 1. The control group received an equal volume of physiological saline intraperitoneally. From day 2 to 4, the treatment groups received various doses of silymarin or N-acetyl cysteine orally once daily, while the control group and the acetaminophen group received an equal volume of water orally. The mortality rate was recorded in all groups. On day 5, all mice were sacrificed for examination.
Silymarin greatly improved the counteracting effects on mortality rate as compared to N-acetyl cysteine.
Silymarin should be further considered as an antidote for patients with acetaminopheninduced acute hepatic injury and delayed treatment.
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