Exploring two distinct gentamicin prescribing protocols in UK hospitals: a mixed-methods realist evaluation.

This is the final version. Available from BMJ Publishing via the DOI in this record. Data availability statement: Data are available upon reasonable request. The raw data cannot be made freely available to share, given the nature of the consents given by participants. However, the corresponding author (ND ORCID ID: 0000-0002-8797-3467) can be contacted to discuss possible secondary analyses of deidentified participant data.OBJECTIVES: Gentamicin is the aminoglycoside antibiotic of choice in the UK. It has a narrow therapeutic index: underdosing results in inefficacy while overdosing is characterised by nephrotoxicity and ototoxicity. To improve patient safety, hospitals have protocols for the prescription of gentamicin, which vary in complexity and approach. This study aimed to explore two distinct protocols for prescribing gentamicin in hospital settings, in order to understand the mechanisms they trigger and the outcomes they achieve. SETTING: A mixed-methods realist evaluation explored gentamicin prescribing protocols in two hospital surgical admissions units in South West England between January and August 2018. Site 1 had a traditional, complex protocol, while site 2 took a simplified protocol. PARTICIPANTS: Testing the initial programme theory (IPT) involved semi-structured audio-recorded interviews of a volunteer sample of healthcare professionals (HCPs) involved in the prescribing and administering process, alongside a clinical audit reviewing accuracy of gentamicin prescribing. OUTCOME MEASURES: Three sequential phases were used to identify factors in a successful protocol: IPT generation; testing; refinement of the IPT. The IPT was generated by literature search and analysis of existing protocols of sites 1 and 2. Refinement of the IPT synthesised the results of the quantitative and qualitative research to identify the key characteristics of a successful protocol. RESULTS: One hundred gentamicin prescriptions were reviewed, with a mean accuracy of gentamicin prescribing at site 1 of 65.67% and at site 2 of 78.79% (p<0.01). Thirty HCPs were interviewed. Key contexts were identified including prescriptiveness, experience and availability of patient information. These triggered hidden mechanisms including uncertainty, fear, confidence and frustration leading to both intended outcomes but also unintended outcomes such as deviation from protocol and unnecessary gentamicin levels. CONCLUSIONS: A simplified prescribing protocol for gentamicin is better accepted by prescribers, leading to better adherence to protocol and more accurate prescribing

Practical quantum key distribution: On the security evaluation with inefficient single-photon detectors

Quantum Key Distribution with the BB84 protocol has been shown to be unconditionally secure even using weak coherent pulses instead of single-photon signals. The distances that can be covered by these methods are limited due to the loss in the quantum channel (e.g. loss in the optical fiber) and in the single-photon counters of the receivers. One can argue that the loss in the detectors cannot be changed by an eavesdropper in order to increase the covered distance. Here we show that the security analysis of this scenario is not as easy as is commonly assumed, since already two-photon processes allow eavesdropping strategies that outperform the known photon-number splitting attack. For this reason there is, so far, no satisfactory security analysis available in the framework of individual attacks.Comment: 11 pages, 6 figures; Abstract and introduction extended, Appendix added, references update

Pressure dependence of the thermoelectric power of single-walled carbon nanotubes

We have measured the thermoelectric power (S) of high purity single-walled carbon nanotube mats as a function of temperature at various hydrostatic pressures up to 2.0 GPa. The thermoelectric power is positive, and it increases in a monotonic way with increasing temperature for all pressures. The low temperature (T < 40 K) linear thermoelectric power is pressure independent and is characteristic for metallic nanotubes. At higher temperatures it is enhanced and though S(T) is linear again above about 100 K it has a nonzero intercept. This enhancement is strongly pressure dependent and is related to the change of the phonon population with hydrostatic pressure.Comment: 4 pages, 3 figure

Comparison of Bond Character in Hydrocarbons and Fullerenes

We present a comparison of the bond polarizabilities for carbon-carbon bonds in hydrocarbons and fullerenes, using two different models for the fullerene Raman spectrum and the results of Raman measurements on ethane and ethylene. We find that the polarizabilities for single bonds in fullerenes and hydrocarbons compare well, while the double bonds in fullerenes have greater polarizability than in ethylene.Comment: 7 pages, no figures, uses RevTeX. (To appear in Phys. Rev. B.

Observation and Assignment of Silent and Higher Order Vibrations in the Infrared Transmission of C60 Crystals

We report the measurement of infrared transmission of large C60 single crystals. The spectra exhibit a very rich structure with over 180 vibrational absorptions visible in the 100 - 4000 cm-1 range. Many silent modes are observed to have become weakly IR-active. We also observe a large number of higher order combination modes. The temperature (77K - 300K) and pressure (0 - 25KBar) dependencies of these modes were measured and are presented. Careful analysis of the IR spectra in conjunction with Raman scattering data showing second order modes and neutron scattering data, allow the selection of the 46 vibrational modes C60. We are able to fit *all* of the first and second order data seen in the present IR spectra and the previously published Raman data (~300 lines total), using these 46 modes and their group theory allowed second order combinations.Comment: REVTEX v3.0 in LaTeX. 12 pages. 8 Figures by request. c60lon

Targeted capture of Dreb subfamily genes as candidates genes for drought tolerance polymorphism in natural population of Coffea canephora.

Coffea canephora, (Robusta), provides 33% of worldwide coffee production, 80% and 22% of Ugandan and Brazilian coffee production, respectively. Abiotic stress such as temperature variations or drought periods, aggravated by climate changes, are factors that affect this production. This sensitivity threatens both the steady supply of quality coffees and the livelihood of millions of people producing coffee. The natural genetic diversity of C. canephora offer a potential for detecting new genetic variants related to drought adaptation. In particular, modifications occurring in genes related to abiotic stress tolerance make these genes candidate for breeding programs in order to enhance the resilience to climate change

Isolation and Monitoring of the Endohedral Metallofullerenes Y@C82 and Sc3@C82:On-Line Chromatographic Separation with EPR Detection

The direct coupling of high-performance liquid chromatography (HPLC) with on-line electron paramagnetic resonance (EPR) detection is demonstrated for monitoring separations of endohedral metallofullerenes (M@C2n). The HPLC-EPR approach readily permits detection of the paramagnetic species, such as Y@C82 and Sc3@C82, in the presence of the dominant empty-cage fullerenes (C60, C70) and diamagnetic metallofullerenes (e.g., M2@C2n). The results indicate that on-line EPR provides a noninvasive, selective detector for HPLC metallofullerene separations that is readily adaptable to air-sensitive and/or labile compounds. Specifically, the “EPR-active” metallofullerenes, Y@C82 and Sc3@C82, are selectively monitored on-line for an initial separation of the metallofullerene fraction from the dominant empty-cage fullerenes utilizing a combination of polystyrene columns. This preparative “cleanup” procedure is followed by HPLC-EPR separation and monitoring of Y@C82 and Sc3@C82 species using a selective tripodal π-acidic-phase column (Trident-Tri-DNP) for the final stages of isolation

Electronic transport, structure, and energetics of endohedral Gd@C82 metallofullerenes

Electronic structure and transport properties of the fullerene C$_{82}$ and the metallofullerene Gd@C$_{82}$ are investigated with density functional theory and the Landauer-Buttiker formalism. The ground state structure of Gd@C$_{82}$ is found to have the Gd atom below the C-C bond on the C$_2$ molecular axis of C$_{82}$. Insertion of Gd into C$_{82}$ deforms the carbon chain in the vicinity of the Gd atoms. Significant overlap of the electron distribution is found between Gd and the C$_{82}$ cage, with the transferred Gd electron density localized mainly on the nearest carbon atoms. This charge localization reduces some of the conducting channels for the transport, causing a reduction in the conductivity of the Gd@C$_{82}$ species relative to the empty C$_{82}$ molecule. The electron transport across the metallofullerene is found to be insensitive to the spin state of the Gd atom.Comment: 13 pages, 7 figures, submitted Nano Let

Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating the C60-C8H8 cocrystal with green or blue light a photochemical reaction was observed leading to a similar product to that of the thermal polymerization.Comment: 26 pages, 8 figures, to appear in Journal of Physical Chemistry B 2nd version: minor changes in wording, accepted version by journa