17 research outputs found

    Vacuum-UV negative photoion spectroscopy of CF3Cl, CF3Br and CF3I

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    Using synchrotron radiation negative ions have been detected by mass spectrometry following vacuum-UV photoexcitation of trifluorochloromethane (CF3_3Cl), trifluorobromomethane (CF3_3Br) and trifluoroiodomethane (CF3_3I). The anions F^-, X^-, F2_2^-, FX^-, CF^-, CF2_2^- and CF3_3^- were observed from all three molecules, where X = Cl, Br or I, and their ion yields recorded in the range 8-35 eV. With the exception of Br^- and I^-, the anions observed show a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation. Dissociative electron attachment, following photoionization of CF3_3Br and CF3_3I as the source of low-energy electrons, is shown to dominate the observed Br^- and I^- signals, respectively. Cross sections for ion-pair formation are put on to an absolute scale by calibrating the signal strengths with those of F^- from both SF6_6 and CF4_4. These anion cross sections are normalized to vacuum-UV absorption cross sections, where available, and the resulting quantum yields are reported. Anion appearance energies are used to calculate upper limits to 298 K bond dissociation energies for D0D^0(CF3_3-X) which are consistent with literature values. We report new data for D0D^0(CF2_2I^--F) ≤ 2.7 ± 0.2 eV and ΔfH2980\Delta_fH^0_{298} (CF2_2I+^+) ≤ (598 ± 22) kJ mol1^{-1}. No ion-pair formation is observed below the ionization energy of the parent molecule for CF3_3Cl and CF3_3Br, and only weak signals (in both I^- and F^-) are detected for CF3_3I. These observations suggest neutral photodissociation is the dominant exit channel to Rydberg state photoexcitation at these lower energies

    Is there an unmet medical need for improved hearing restoration?

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    Hearing impairment, the most prevalent sensory deficit, affects more than 466 million people worldwide (WHO). We presently lack causative treatment for the most common form, sensorineural hearing impairment; hearing aids and cochlear implants (CI) remain the only means of hearing restoration. We engaged with CI users to learn about their expectations and their willingness to collaborate with health care professionals on establishing novel therapies. We summarize upcoming CI innovations, gene therapies, and regenerative approaches and evaluate the chances for clinical translation of these novel strategies. We conclude that there remains an unmet medical need for improving hearing restoration and that we are likely to witness the clinical translation of gene therapy and major CI innovations within this decade

    Implantation of multiply charged carbon ions in water ice

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    Context. Several objects in the Solar System like Europa, Ganymede and Callisto have frozen surface (main component: H2O). The associated thickness is bigger than the penetration depth of the relevant projectile ions. Additionally, other species such as H2O2, SO2 and CO2 have been detected on these surface. The formation mechanisms of these molecules are still under discussion. Aims. We present new experimental results on the implantation of 13Cq+ (q = 2, 3) ions at an energy of 30 keV in water ice at low temperatures (15 and 80 K). Experiments with multiply charged ions at energies of tens of keV are particularly relevant to simulating the complexity of the irradiation environment to which the surfaces of the icy moons in the outer solar system are exposed. Methods. The experiments were performed at the low energy ion beam facility ARIBE of GANIL in Caen (France). 30 keV 13Cq+ (q = 2, 3) ions have been used to bombard solid H,2O surface which were frozen at 15K and 80K. Fourier Transform Infrared Spectrometer (FTIR) was used to analyze the sample in the 5000 - 600 cm-1 (2-16.7 μm) region with a spectral resolution of 1 cm-1. Results. The results of our experiments indicate that implantation produces 13CO2 with yields in the range of 0.32-0.57 molecules ion-1. This yield seems to be independent of the temperature of the ices in the range studied. We have estimated the time scale necessary to accumulate by implantation of magnetospheric carbon ions the observed quantity of carbon dioxide on the surface of Europa, a Jovian moon. This time scale is of the order of 1.0-1.3x104 yrs which is higher than that evaluated for carbon dioxide production by other relevant processes. Conclusions.We conclude that although a relevant quantity of CO2 can be formed by carbon ion implantation, this is not the dominant formation mechanism at Europa

    Demonstrating the accuracy of an in-hospital ambulatory patient monitoring solution in measuring respiratory rate

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    This paper presents clinical testing conducted to evaluate the accuracy of Aingeal, a wireless in-hospital patient monitor, in measuring respiration rate via impedance pneumography. Healthy volunteers were invited to simultaneously wear a CE Marked Aingeal vital signs monitor and a capnograph, the current gold standard in respiration rate measurement. During the test, participants were asked to undergo a series of defined breathing protocols which included normal breathing, paced breathing between 8-23 breaths per minute (bpm) and a recovery period following moderate exercise. Statistical analysis of the data collected shows a mean difference of -0.73, a standard deviation of 1.61, limits of agreement of -3.88 and +2.42 bpm and a P-value of 0.22. This testing demonstrates comparable performance of the Aingeal device in measuring respiration rate with a well-accepted and widely used alternative method. © 2013 IEEE

    Identifying barriers and enablers to rigorous conduct and reporting of preclinical laboratory studies.

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    Use of rigorous study design methods and transparent reporting in publications are 2 key strategies proposed to improve the reproducibility of preclinical research. Despite promotion of these practices by funders and journals, assessments suggest uptake is low in preclinical research. Thirty preclinical scientists were interviewed to better understand barriers and enablers to rigorous design and reporting. The interview guide was informed by the Theoretical Domains Framework, which is a framework used to understand determinants of current and desired behavior. Four global themes were identified; 2 reflecting enablers and 2 reflecting barriers. We found that basic scientists are highly motivated to apply the methods of rigorous design and reporting and perceive a number of benefits to their adoption (e.g., improved quality and reliability). However, there was varied awareness of the guidelines and in implementation of these practices. Researchers also noted that these guidelines can result in disadvantages, such as increased sample sizes, expenses, time, and can require several personnel to operationalize. Most researchers expressed additional resources such as personnel and education/training would better enable the application of some methods. Using existing guidance (Behaviour Change Wheel (BCW); Expert Recommendations for Implementing Change (ERIC) project implementation strategies), we mapped and coded our interview findings to identify potential interventions, policies, and implementation strategies to improve routine use of the guidelines by preclinical scientists. These findings will help inform specific strategies that may guide the development of programs and resources to improve experimental design and transparent reporting in preclinical research

    Photographing Absence in Deathscapes

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    How do visual methods, particularly the practice of photography, help us to visualise and understand absence in deathscapes? In this paper I will argue that photographs, with their ability to freeze moments, are able to capture what I term points of praxis – moments in which practices by individuals inscribe meaning onto deathscapes, and in that intense and captured presence, evoke the feeling of absent individuals. Such points of praxis can exist in two ways – the praxis of the body and the praxis of objects – both of which I will illuminate with the use of visual ethnographic methods. To support my argument, I present work taken from a three‐year visual ethnographic study of Bukit Brown Cemetery, specifically drawing on the social and cultural documentation of the Hungry Ghost Festival
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