Removal of methylated arsenic in groundwater with iron filings

Field and laboratory experiments were conducted to study the potential use of Fe filings to remove monomethyl arsenate (MMA) and dimethyl arsenate (DMA) from contaminated waters. Batch experiments show that the affinity of MMAfor Fe filings is comparable to that of inorganic arsenate, but lower than that for arsenite. In contrast, very little DMA was retained by Fe filings or their corrosion products. The wide range of affinities of different As species for Fe filings was confirmed by a series of retention and selective-leaching experiments using small columns and As-spiked groundwater. The effectiveness of Fe filings was also demonstrated with a field deployment at a U.S. Superfund site where groundwater is highly contaminated with both organic and inorganic As species. Over the course of 4 months, a 3 L cartridge of Fe filings removed > 85% of As contained in 16000 L of groundwater containing 1-1.5 mg/L total dissolved As, approximately 30% of which was organic As. The results indicate that Fe filings could be used to treat groundwater contaminated with MMA, which is the main organic form of As at most contaminated sites. Indications of partial demethylation in the column of Fe filings suggest conditions might be optimized further to enhance the removal of DMA.     

Determination of phytoestrogens in dietary supplements by LC-MS/MS

Labelling data quantifying the exact content of individual phytoestrogen analytes in dietary supplements are generally poor. As these products are commonly used in the management of menopause symptoms, any clinical benefits would be dependent on the exact dosage of isoflavones received. Well-established extraction procedures and updated isotope dilution mass spectrometry liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) have been used to accurately quantify the concentrations of ten common isoflavones in 35 dietary supplement samples on sale in the UK, Canada and Italy. Concentration-specific ionization suppression is described for biochanin A and formononetin. All supplements contained phytoestrogens. The soya isoflavones (genistein, daidzein, glycitein) were present in all products and the majority also contained the red clover isoflavones (biochanin A, formononetin) and some the Kudzu isoflavones (daidzein, puerarin). The content of total isoflavones per dose ranged from <1 to 53 mg. Trace amounts of coumestrol were found in six products. Other less common analytes, the prenylnaringenins (6-prenylnaringenin, 8-prenylnaringenin, 6,8-diprenylnaringenin) were not found in any of the products. Only 14 of 35 supplements were found to deliver more than or equal to 40 mg day(-1) of aglycone isoflavones, a consensus dose value recognized as delivering therapeutic benefit. Eleven did not match label claims. Six delivered less than 10 mg day (-1) of isoflavones. There has been little improvement in the overall quality of industry labelling in the five years since this was last investigated. Consequently, the public, retailers and healthcare professionals should consider using standardized isoflavone supplements, which are supported by analytical measurements.     

Claims of alleged medical negligence in refractive surgery: causes and avoidance.

PURPOSE: To identify the issues cited in claims for alleged medical negligence in cases of refractive surgery. METHODS: One hundred and one cases of alleged medical negligence following refractive surgery were analysed by a single expert witness. Valid features of the statement of claim and issues identified by the expert as being relevant to the outcome were assessed. RESULTS: Sixty-five percentage of claims included issues of consent. In one third of these cases the Claimant had particular risk factors for which especially careful counselling was warranted. For 29% of claims there were contraindications to surgery. In 24% there was surgical error resulting in a compromised outcome. In 23% there was avoidable delay in instituting medical management for post-operative complications. Four percentage of cases were precipitated by a second opinion where the clinician giving the opinion was not fully conversant with the facts. CONCLUSIONS: The number of claims could be substantially reduced by: (1) Instituting proper policies for consent with full documentation throughout the process; (2) Ensuring that surgeons are adequately trained in evaluating pre-operative tests and allowing surgeons adequate time to assess patients prior to surgery; (3) Moderating the case-load for surgery; (4) Ensuring that patients have easy access to medical care post-operatively; (5) Keeping comprehensive and accurate records.     

Cross-Domain Image Matching with Deep Feature Maps

International Journal of Computer Vision - We investigate the problem of automatically determining what type of shoe left an impression found at a crime scene. This recognition problem is made...     

Hypermutability of mouse chromosome 2 during the development of x-ray-induced murine myeloid leukemia

In an effort to identify the precise role of a deletion at regions D-E of mouse chromosome 2 [del2(D-E)] during the development of radiation-induced myeloid leukemia, we conducted a serial sacrifice study in which metaphase chromosomes were examined by the G-banding technique. Such metaphase cells were collected from x-irradiated mice during the period of transformation of some of the normal hematopoietic cells to the fully developed leukemic phenotype. A group of 250 CBA/Ca male mice (10-12 weeks old) were exposed to a single dose of 2 Gy of 250-kilovolt-peak x-rays; 42 age-matched male mice served as controls. Groups of randomly selected mice were sacrificed at 20 hr, 1 week, and then at intervals of 3 months up to 24 months after x-irradiation. Slides for cytogenetic, hematological, and histological examination were prepared for each animal at each sacrifice time. An expansion of cells with lesions on one copy of chromosome 2 was evident in 20-25% of treated mice at each sacrifice time. The majority of such lesions were translocations at 2F or 2H, strongly suggesting hypermutability of these sites on mouse chromosome 2. No lesions were found in control mice. The finding leads to the possibility that genomic lesions close to 2D and 2E are aberrants associated with radiation leukemogenesis, whereas a single clone of cells with a del2(D-E) may lead directly to overt leukemia. The data also indicate that leukemic transformation arises from the cumulative effects of multiple genetic events on chromosome 2, reinforcing the thesis that multiple steps of mutation occur in the pathogenesis of cancer.