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Summary
Accelerator mass spectrometry (AMS) is the most sensitive, safe and precise analytical method for quantifying long-lived isotope in biomedical research with animals as well as human beings. In Korea, AMS Laboratory has been operating successfully for years measuring especially archeological samples for 14C dating. In this year, a biological sample pretreatment facility was setup and we have also started to work on biomedical applications. As a preliminary study, we have measured the natural background levels of 14C in tissues and blood of humans and rats. The results were agreed with the other reported levels and gave stable and reproducible results within 1-2%.
A simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the determination of zinc pyrithione (ZnPT) and pyrithione (PT) in shampoos. The method consisted of a liquid–liquid extraction for sample preparation. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode via the positive electrospray ionization interface. A linear regression (weighted 1/x) was used to fit calibration curves over the concentration range of 50–2000 ng/mL for both ZnPT and PT. Excellent linearity (r 2 ≥ 0.9996) was achieved for all. The method was validated and found to be accurate (95.9–108.2% for ZnPT and 94.9–110.4% for PT), precise, and selective. Analytes in shampoos were found to be stable in the autosampler (6 °C for 6 h), in room temperature (for 6 h), and after three freeze–thaw cycles, and recovery of analytes was reproducible (90.8–94.6% for ZnPT and 90.2–96.3% for PT).
Abstract
The most important recent developments in radiometric techniques have been the operation of high efficiency HPGe detectors with anticosmic or antiCompton shielding often placed underground, ship-board measurements of 234Th using gamma-spectrometry or beta-counting and underwater gamma-spectrometry. In mass spectrometry techniques, the availability of high resolution ICP-MS and applications of AMS for the analysis of long-lived radionuclides have opened doors for investigations which previously required too large samples, or were not possible because of lack of sensitivity. These developments are illustrated by several examples of marine radioactivity studies, which include contaminated sites (e.g., Fangataufa Atoll) and open ocean studies (e.g., the Atlantic Ocean) as well as analyses of IAEA reference materials. A comparison of Pu results obtained by alpha-spectrometry, ICP-MS and AMS has shown that a reasonably good agreement has been obtained between all three methods.
Abstract
Background and aims
The aim of the present study was to provide a phenomenological perspective of individuals who actively engage in street-level prostitution and identified a lifestyle addiction associated with their activities.
Methods
We interviewed 25 women who were incarcerated in American county jails (at the time of interviews) for prostitution crimes. The transcripts were analyzed for themes that represented the shared consensus of the research participants.
Results
Four negative psychological dynamics related to prostitution. First, participants described accounts of physical and emotional violence which they experienced at the hand of clients and others involved in the lifestyle. Second, interviewees explained an extreme dislike for their actions relating to and involving prostitution. These individuals did not describe themselves as being sexually addicted; sex was means to a desired end. Third, participants described how prostitution's lifestyle had evolved into something which they conceptualized as an addiction. As such, they did not describe themselves as feeling addicted to sex acts — but to lifestyle elements that accompanied prostitution behaviors. Finally, participants believed that freedom from prostitution's lifestyle would require social service assistance in order to overcome their lifestyle addiction.
Conclusions
The results show that, although the prostitutes repeatedly and consistently used the term “addiction” when describing their lifestyles, they did not meet the DSM-IV-TR criteria for addiction. Rather, they shared many of the same psychological constructs as do addicts (e.g., feeling trapped, desiring escape, needing help to change), but they did not meet medical criteria for addictive dependence (e.g., tolerance or withdrawal).
Sorghum bicolor (L.) Moench contains various phenolic compounds such as anthocyanin. Eleven sorghum accessions were classified into five groups by grain colour and their antioxidant activities were measured as well as the contents of total phenolic compounds (TPC) and anthocyanins in sorghum grains. The grain colour was related to TPC content, but not to monomelic anthocyanin content. Moreover, the overall patterns of antioxidant activity levels in 2,2-Diphenyl-1-picrylhydrazyl (DPPH) or 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay were similar to those of the TPC content. Correlations between TPC and anthocyanin contents were statistically significant and positive (P < 0.05). TPC content showed also a strong positive correlation to DPPH and ABTS antioxidant activities. The results provide the basic data for breeding of sorghum varieties containing large amounts of antioxidants.
Silicon (Si) is essential for normal growth and development in plants and is also beneficial for their responses to wounding. However, the mechanisms by which Si acts to mitigate the effects of wounding is not fully understood. This effect possibly occurs through a reduction in the oxidative stresses associated with wounding. Here, we tested this possibility by investigating the effects of applying different concentrations of Si (0,5 and 1,0 mM) to rice plants under wounding stress for a period of 6 and 12 h. We found that a higher uptake of Si was signifiacntly associated with an increase in leaf chlorophyll contet. In response to wounding induced oxidative stress, the extent of lipid bilayer peroxidation was reduced in a dose-dependent manner by Si application for 6 or 12 h. Activity of the catalase enzyme was initially lowered by Si treatment; however, at 1.0 mM Si, catalase activity increased significantly after 12h of wounding stress. A similar response was also observed for a peroxidase enzyme. Polyphenol oxidase showed a significant reduction in activity. We conclude that Si application does not only improve leaf chlorophyll content but can also overcome the oxidative stress due wounds or physical injuries.
Summary
Profiles of volatile secondary metabolites (VSM) in Mediterranean and Continental Festuca arundinacea, either endophyte free or infected with the fungal endophyte Neotyphodium coenophialum strain AR542, were determined using gas chromatography-mass spectrometry (GC-MS). The profile of VSM in the endophyte-free Mediterranean F. arundinacea germplasm was similar to that of endophyte-free Continental F. arundinacea germplasm. However, the VSM profile in AR542-infected Mediterranean F. arundinacea was different to that in AR542-infected Continental F. arundinacea. Compound 1, identified as N-acetylnorloline, was detected in AR542-infected Mediterranean F. arundinacea as being sevenfold greater compared with its level in AR542-infected Continental F. arundinacea. Levels of compounds 2, 4, and 5 detected in AR542-infected Mediterranean F. arundinacea were significantly lower when compared with their levels in the AR542-infected Continental F. arundinacea. Levels of compound 3 were similar in both germplasms infected with endophyte strain AR542. The levels of compounds 2, 4, and 5 but not compound 3 were different between AR542 infected and endophyte free depending on germplasm. On the basis of the mass spectra obtained, compounds 2, 3, 4, and 5 were identified as tridecanoic acid methyl ester, n-capric acid, 11, 14, 17-eicosatrienoic acid, and linoleic acid ethyl ester, respectively. Our results highlight key differences between the Mediterranean and Continental germplasms. Comparison of the VSM of AR542-infected Mediterranean F. arundinacea with AR542-infected Continental F. arundinacea showed that there are quantitative differences between the two germplasms. These differences, which may impact on grazing systems involving horses, most probably arose as a result of intrinsic genetic differences between the two germplasms and are yet to be indentified.
