Cessation Of Usage Research Articles

Persistence of PFOA Pollution at a PTFE Production Site and Occurrence of Replacement PFASs in English Freshwaters Revealed by Sentinel Species, the Eurasian Otter (Lutra lutra).

Concentrations of 33 PFASs were determined in 20 Eurasian otters, sampled 2015-2019, along a transect away from a factory, which used PFOA in PTFE manufacture. Despite cessation of usage in 2012, PFOA concentrations remained high near the factory (>298 μg/kg ww <20 km from factory) and declined with increasing distance (<57 μg/kg ww >150 km away). Long-chain legacy PFASs dominated the Σ33PFAS profile, particularly PFOS, PFOA, PFDA, and PFNA. Replacement compounds, PFECHS, F-53B, PFBSA, PFBS, PFHpA, and 8:2 FTS, were detected in ≥19 otters, this being the first report of PFBSA and PFECHS in the species. Concentrations of replacement PFASs were generally lower than legacy compounds (max: 70.3 μg/kg ww and 4,640 μg/kg ww, respectively). Our study underscores the utility of otters as sentinels for evaluating mitigation success and highlights the value of continued monitoring to provide insights into the longevity of spatial associations with historic sources. Lower concentrations of replacement, than legacy, PFASs likely reflect their lower bioaccumulation potential, and more recent introduction. Continued PFAS use will inevitably lead to increased environmental and human exposure if not controlled. Further research is needed on fate, toxicity, and bioaccumulation of replacement compounds.

Quantitative assessment of growing hair counts, thickness and colour during and after treatments with a low-fluence, home-device laser: a randomized controlled trial.

At-home laser and intense pulsed-light hair removal continues to grow in popularity and availability. A relatively limited body of evidence is available on the course of hair growth during and after low-fluence laser usage. To assess growing hair counts, thickness and colour quantitatively during and after cessation of low-fluence laser treatment. Thirty-six women with skin phototypes I-IV and light to dark-brown axillary hairs were included. Entire axillary regions were randomized to zero or eight self-administered weekly treatments with an 810-nm home-use laser at 5·0-6·4 J cm(-2). Standardized clinical photographs were taken before each treatment and up to 3 months after the final treatment for computer-aided quantification of growing hair counts, thickness and colour. Thirty-two women completed the study protocol. During sustained treatment, there was a reduction in growing hair that reached a plateau of up to 59%, while remaining hairs became up to 38% thinner and 5% lighter (P < 0·001). The majority of subjects (77%) reported 'moderately' to 'much less hair' in treated than untreated axilla, and assessed remaining hairs as thinner and lighter (≥ 60%). After treatment cessation, hair growth gradually returned to baseline levels, and 3 months after the final treatment the count and thickness of actively growing hair exceeded pretreatment values by 29% and 7%, respectively (P ≤ 0·04). Sustained usage of low-fluence laser induced a stable reduction of growing hair counts, thickness and colour. The reduction was reversible and hairs regrew beyond baseline values after cessation of usage. Computer-aided image analysis was qualified for quantification of hair counts, thickness and colour after laser epilation.

The influence of environmental factors and management methods on the vegetation of mesic grasslands in a central European mountain range

We examined how environmental factors combined with the diverse ways of the extensive management of mesic mountain grasslands affect species composition and diversity in the Polish part of Central Sudetes Mts. Based on the data from 100 research plots altitude, organic matter content and exchangeable magnesium in the soil, as well as the maximum soil water capacity and amount of sand fraction significantly affected species composition. Among the management methods, a significant effect on the differentiation of species composition was observed following the cessation of usage and mowing. Mown meadows had the highest share of forbs in the biomass, whereas those abandoned ones were dominated by tall and expansive grasses, mainly Calamagrostis epigejos. The species richest grasslands occurred in areas with soils of high water capacity, containing high concentrations of calcium and low amounts of total nitrogen. No significant effect of management methods on the total number of species as well as on the number of forb species was observed. Mown pastures had the highest mean value of the Shannon–Wiener diversity index.

Quantitative Urine Levels of Abusable Drugs for Clinical Purposes

Urine screening by polarized fluorescent immunoassay (PFI), which can quantitate concentrations of drugs of abuse within specific ranges, has recently been developed. It is rapid and inexpensive, so it can be clinically used on a routine basis. Reported here are the urine concentrations of marijuana, cocaine, phencyclidine, and amphetamine metabolites in 790 clinical patients who either sought medical detoxification for a self-diagnosis of addiction, or a counseling and urine testing program with the self-perception that they were occasional, nonaddicted users. Mean urine concentrations of cocaine, phencyclidine, and amphetamine, but not marijuana, metabolites were significantly higher in addicted than nonaddicted patients. Sequential urine tests in addicts progressively demonstrate reduced urine concentrations for as long as several weeks if cessation of usage has occurred. Nonaddicted, occasional users usually produce a negative urine sample within 2 to 3 days. Despite some overlap in urine concentrations between addicted and nonaddicted users at the time of admission for treatment, quantitative urine testing is a valuable adjunct in the clinical diagnosis and treatment of drug abuse.