Automated cold vapour flow-injection analysis of mercury at high concentrations

Continuous-flow cold vapour- atomic fluorescence spectrometry is shown to be an extremely sensitive technique for the determination of mercury with detection limits typically below 0.01 μg l-1. Linear calibration ranges were found to be at least four orders of magnitude (i.e. up to 0.1 mg l-1). Samples with concentrations exceeding the linear range are susceptible to self-absorption, and may, in severe cases, cause carry-over problems between samples. The flow-injection approach has been utilized to extend the upper limit of the linear calibration range allowing determinations up to 10 mg l-1 of mercury. A range of certified reference materials and zinc battery anodes have been successfully analysed with a minimal number of sample dilutions

Arsenic speciation in beverages by direct injection-ion chromatography hydride generation atomic fluorescence spectrometry

The procedure developed allows the direct speciation of arsenic in these samples with good sensitivity, selectivity, precision and accuracy. Detection limits determined using the optimized conditions were found to be between 0.16 and 2.9ng ml−1 for arsenite, dimethylarsinic acid, monomethylarsonic acid and arsenate, while standard addition studies showed that the procedure is free from matrix interferences. As no certified reference materials are available for these analytes or matrices, validation was carried out by studying spike recoveries and by comparison of results with an alternative technique

Quick and robust method for trace determination of MeHg in rice and rice products without derivatisation

Peer reviewedPostprin

Generation of otic lineages from integration-free human-induced pluripotent stem cells reprogrammed by mRNAs

Damage to the sensory hair cells and the spiral ganglion neurons of the cochlea leads to deafness. Induced pluripotent stem cells (iPSCs) are a promising tool to regenerate the cells in the inner ear that have been affected by pathology or have been lost. To facilitate the clinical application of iPSCs, the reprogramming process should minimize the risk of introducing undesired genetic alterations while conferring the cells the capacity to differentiate into the desired cell type. Currently, reprogramming induced by synthetic mRNAs is considered to be one of the safest ways of inducing pluripotency, as the transgenes are transiently delivered into the cells without integrating into the genome. In this study, we explore the ability of integration-free human-induced pluripotent cell lines that were reprogrammed by mRNAs, to differentiate into otic progenitors and, subsequently, into hair cell and neuronal lineages. hiPSC lines were induced to differentiate by culturing them in the presence of fibroblast growth factors 3 and 10 (FGF3 and FGF10). Progenitors were identified by quantitative microscopy, based on the coexpression of otic markers PAX8, PAX2, FOXG1, and SOX2. Otic epithelial progenitors (OEPs) and otic neuroprogenitors (ONPs) were purified and allowed to differentiate further into hair cell-like cells and neurons. Lineages were characterised by immunocytochemistry and electrophysiology. Neuronal cells showed inward Na+ () currents and outward () and inward K+ () currents while hair cell-like cells had inward and outward delayed rectifier K+ currents, characteristic of developing hair cells. We conclude that human-induced pluripotent cell lines that have been reprogrammed using nonintegrating mRNAs are capable to differentiate into otic cell types

Exploring Consumer and Patient Knowledge, Behavior, and Attitude Toward Medicinal and Lifestyle Products Purchased From the Internet: A Web-Based Survey.

BACKGROUND: In recent years, lifestyle products have emerged to help improve people's physical and mental performance. The Internet plays a major role in the spread of these products. However, the literature has reported issues regarding the authenticity of medicines purchased from the Internet and the impact of counterfeit medicines on public health. Little or no data are available on the authenticity of lifestyle products and actual toxicity associated with their use and misuse. OBJECTIVE: Our aim was to investigate consumer and patient attitudes toward the purchase of lifestyle products from the Internet, their knowledge of product authenticity and toxicity, and their experiences with counterfeit lifestyle products. METHODS: A Web-based study was performed between May 2014 and May 2015. Uniform collection of data was performed through an anonymous online questionnaire. Participants were invited worldwide via email, social media, or personal communication to complete the online questionnaire. A total of 320 participants completed the questionnaire. RESULTS: The results of the questionnaire showed that 208 (65.0%) participants purchased lifestyle products from the Internet mainly due to convenience and reduced cost. More than half (55.6%, 178/320) of participants purchased cosmetic products, whereas only a minority purchased medicinal products. Yet, 62.8% (201/320) of participants were aware of the presence of counterfeit lifestyle products from the Internet, and 11.9% (38/320) experienced counterfeit products. In only 0.9% (3/320) of those cases were counterfeit lifestyle products reported to authorities. Moreover, 7.2% (23/320) of the participants experienced adverse effects due to counterfeit lifestyle products. CONCLUSIONS: In summary, patients experienced counterfeit lifestyle products that resulted in adverse effects on their health. Although certain adverse effects were reported in this study, counterfeit products were underreported to authorities. Further public awareness campaigns and patient education are needed

Developing Historic Building Information Modelling Guidelines and Procedures for Architectural Heritage in Ireland

Cultural heritage researchers have recently begun applying Building Information Modelling (BIM) to historic buildings. The model is comprised of intelligent objects with semantic attributes which represent the elements of a building structure and are organised within a 3D virtual environment. Case studies in Ireland are used to test and develop the suitable systems for (a) data capture/digital surveying/processing (b) developing library of architectural components and (c) mapping these architectural components onto the laser scan or digital survey to relate the intelligent virtual representation of a historic structure (HBIM). While BIM platforms have the potential to create a virtual and intelligent representation of a building, its full exploitation and use is restricted to narrow set of expert users with access to costly hardware, software and skills. The testing of open BIM approaches in particular IFCs and the use of game engine platforms is a fundamental component for developing much wider dissemination. The semantically enriched model can be transferred into a WEB based game engine platform

Standing in a Garden of Forking Paths

According to the Path Principle, it is permissible to expand your set of beliefs iff (and because) the evidence you possess provides adequate support for such beliefs. If there is no path from here to there, you cannot add a belief to your belief set. If some thinker with the same type of evidential support has a path that they can take, so do you. The paths exist because of the evidence you possess and the support it provides. Evidential support grounds propositional justification. The principle is mistaken. There are permissible steps you may take that others may not even if you have the very same evidence. There are permissible steps that you cannot take that others can even if your beliefs receive the same type of evidential support. Because we have to assume almost nothing about the nature of evidential support to establish these results, we should reject evidentialism

Mechanotransduction is required for establishing and maintaining mature inner hair cells and regulating efferent innervation

In the adult auditory organ, mechanoelectrical transducer (MET) channels are essential for transducing acoustic stimuli into electrical signals. In the absence of incoming sound, a fraction of the MET channels on top of the sensory hair cells are open, resulting in a sustained depolarizing current. By genetically manipulating the in vivo expression of molecular components of the MET apparatus, we show that during pre-hearing stages the MET current is essential for establishing the electrophysiological properties of mature inner hair cells (IHCs). If the MET current is abolished in adult IHCs, they revert into cells showing electrical and morphological features characteristic of pre-hearing IHCs, including the re-establishment of cholinergic efferent innervation. The MET current is thus critical for the maintenance of the functional properties of adult IHCs, implying a degree of plasticity in the mature auditory system in response to the absence of normal transduction of acoustic signals

MET currents and otoacoustic emissions from mice with a detached tectorial membrane indicate the extracellular matrix regulates Ca2+ near stereocilia

The tectorial membrane (TM) is an acellular structure of the cochlea that is attached to the stereociliary bundles of the outer hair cells (OHCs), electromotile cells that amplify motion of the cochlear partition and sharpen its frequency selectivity. Although the TM is essential for hearing, its role is still not fully understood. In Tecta/Tectb−/− double knockout mice, in which the TM is not coupled to the OHC stereocilia, hearing sensitivity is considerably reduced compared with that of wild‐type animals. In vivo, the OHC receptor potentials, assessed using cochlear microphonics, are symmetrical in both wild‐type and Tecta/Tectb−/− mice, indicating that the TM does not bias the hair bundle resting position. The functional maturation of hair cells is also unaffected in Tecta/Tectb−/− mice, and the resting open probability of the mechanoelectrical transducer (MET) channel reaches values of ∼50% when the hair bundles of mature OHCs are bathed in an endolymphatic‐like Ca2+ concentration (40 μM) in vitro. The resultant large MET current depolarizes OHCs to near –40 mV, a value that would allow optimal activation of the motor protein prestin and normal cochlear amplification. Although the set point of the OHC receptor potential transfer function in vivo may therefore be determined primarily by endolymphatic Ca2+ concentration, repetitive acoustic stimulation fails to produce adaptation of MET‐dependent otoacoustic emissions in vivo in the Tecta/Tectb−/− mice. Therefore, the TM is likely to contribute to the regulation of Ca2+ levels around the stereocilia, and thus adaptation of the OHC MET channel during prolonged sound stimulation

Aging of the mammalian gastrointestinal tract: a complex organ system

Gastrointestinal disorders are a major cause of morbidity in the elderly population. The gastrointestinal tract is the most complex organ system; its diverse cells perform a range of functions essential to life, not only secretion, digestion, absorption and excretion, but also, very importantly, defence. The gastrointestinal tract acts not only as a barrier to harmful materials and pathogens but also contains the vast number of beneficial bacterial populations that make up the microbiota. Communication between the cells of the gastrointestinal tract and the central nervous and endocrine systems modifies behaviour; the organisms of the microbiota also contribute to this brain–gut–enteric microbiota axis. Age-related physiological changes in the gut are not only common, but also variable, and likely to be influenced by external factors as well as intrinsic aging of the cells involved. The cellular and molecular changes exhibited by the aging gut cells also vary. Aging intestinal smooth muscle cells exhibit a number of changes in the signalling pathways that regulate contraction. There is some evidence for age-associated degeneration of neurons and glia of the enteric nervous system, although enteric neuronal losses are likely not to be nearly as extensive as previously believed. Aging enteric neurons have been shown to exhibit a senescence-associated phenotype. Epithelial stem cells exhibit increased mitochondrial mutation in aging that affects their progeny in the mucosal epithelium. Changes to the microbiota and intestinal immune system during aging are likely to contribute to wider aging of the organism and are increasingly important areas of analysis. How changes of the different cell types of the gut during aging affect the numerous cellular interactions that are essential for normal gut functions will be important areas for future aging research