117 research outputs found

    Metals in Crawfish

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    Impact of Lidocaine on Pain-Related Grooming in Cuttlefish

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    Nociception is the neural process of encoding noxious stimuli and is typically accompanied by a reflex withdrawal response away from the potentially injurious stimulus. Studies on nociception in cephalopods have so far focused on octopus and squid, with no investigations to our knowledge on cuttlefish. Yet, these are an important species both in scientific and commercial use. Therefore, the present study demonstrated that a standard pain stimulus, acetic acid, induced grooming behaviour directed towards the injection site in cuttlefish and that the injection of lidocaine reduces grooming behaviours in acetic-acid-injected cuttlefish. Wound-directed behaviour demonstrates that the animal is aware of the damage; thus, when subjecting these animals to any painful treatments in the laboratory, researchers should consider alleviating pain by the administration of pain-relieving drugs

    Welfare Challenges Influence the Complexity of Movement: Fractal Analysis of Behaviour in Zebrafish

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    The ability to assess welfare is an important refinement that will ensure the good condition of animals used in experimentation. The present study investigated the impact of invasive procedures on the patterns of movement of zebrafish (Danio rerio). Recordings were made before and after fin clipping, PIT tagging and a standard pain test and these were compared with control and sham handled zebrafish. The fractal dimension (FD) from the 3D trajectories was calculated to determine the effect of these treatments on the complexity of movement patterns. While the FD of zebrafish trajectories did not differ over time in either the control or sham group, the FDs of the treatment groups reduced in complexity. The FD of fish injected with different strengths of acetic acid declined in a dose-dependent manner allowing us to develop an arbitrary scale of severity of the treatments. The 3D trajectory plots from some groups indicated the presence of repetitive swimming patterns akin to stereotypical movements. When administered with lidocaine, which has analgesic properties, the movement complexity of fin clipped fish reverted to a pattern that resembled that of control fish. Fractal analysis of zebrafish locomotion could potentially be adopted as a tool for fish welfare assessment

    Evaluation of antibiotic prescribing for ambulatory patients seeking primary dental care services in a Public Hospital in Ghana : a clinical audit study

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    Background: One in ten of all antibiotic prescriptions globally are for dental conditions with 80% of them being inappropriate making it a potential driver of antimicrobial resistance. The study aimed to evaluate the appropriateness of antibiotic use among ambulatory patients seeking dental care services in a public hospital in Ghana. Methods: A retrospective clinical audit was conducted by extracting the medical records of all patients seeking dental care at the ambulatory care clinic of Keta Municipal Hospital (KMH) from January 2020 to December 2020 using the hospital’s electronic database. Descriptive statistics, bivariate and multivariate analysis were performed on the data collected. Results: Overall, 1433 patient medical records were extracted from the database within the study period. The mean age of the patients identified was 39.9 years with almost two thirds being female. Majority (91.1%, n=1306) of them were attended to by a dental nurse. 88.6% (n=1269) of the patients received antibiotics and 87.5% (n=1254) of antibiotics prescribed were non-compliant with Ghana Standard Treatment Guidelines. Three-quarters of the dental conditions were managed with dual antibiotics comprising of amoxicillin and metronidazole. Antibiotic prescription was associated with the age, gender, the type of prescriber and the type of dental condition diagnosed. Conclusion: There is a high usage of antibiotics for dental conditions managed at the outpatient section of the hospital and most are inappropriate. Development of local guidelines supported by education of dental clinicians on empiric use of antibiotics is a suitable target for the antimicrobial stewardship (AMS) team to address in KMH

    Automated monitoring of behaviour in zebrafish after invasive procedures

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    Fish are used in a variety of experimental contexts often in high numbers. To maintain their welfare and ensure valid results during invasive procedures it is vital that we can detect subtle changes in behaviour that may allow us to intervene to provide pain-relief. Therefore, an automated method, the Fish Behaviour Index (FBI), was devised and used for testing the impact of laboratory procedures and efficacy of analgesic drugs in the model species, the zebrafish. Cameras with tracking software were used to visually track and quantify female zebrafish behaviour in real time after a number of laboratory procedures including fin clipping, PIT tagging, and nociceptor excitation via injection of acetic acid subcutaneously. The FBI was derived from activity and distance swum measured before and after these procedures compared with control and sham groups. Further, the efficacy of a range of drugs with analgesic properties to identify efficacy of these agents was explored. Lidocaine (5 mg/L), flunixin (8 mg/L) and morphine (48 mg/L) prevented the associated reduction in activity and distance swum after fin clipping. From an ethical perspective, the FBI represents a significant refinement in the use of zebrafish and could be adopted across a wide range of biological disciplines

    Superstring Cosmology

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    Aspects of superstring cosmology are reviewed with an emphasis on the cosmological implications of duality symmetries in the theory. The string effective actions are summarized and toroidal compactification to four dimensions reviewed. Global symmetries that arise in the compactification are discussed and the duality relationships between the string effective actions are then highlighted. Higher-dimensional Kasner cosmologies are presented and interpreted in both string and Einstein frames, and then given in dimensionally reduced forms. String cosmologies containing both non-trivial Neveu-Schwarz/Neveu-Schwarz and Ramond-Ramond fields are derived by employing the global symmetries of the effective actions. Anisotropic and inhomogeneous cosmologies in four-dimensions are also developed. The review concludes with a detailed analysis of the pre-big bang inflationary scenario. The generation of primordial spectra of cosmological perturbations in such a scenario is discussed. Possible future directions offered in the Horava-Witten theory are outlined.Comment: 161 pages, latex with epsf, 15 figures. Minor changes, additional references and figures. Version to appear in Physics Report

    Response to: 'letter to the editor : "A multifaceted strategy is needed to limit the over-the-counter sale of antimicrobials"'

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    We thank the authors for their letter relating to our paper ‘Selling antibiotics without prescriptions among community pharmacies and drug outlets: a simulated client study from Ghana’ [Citation1,Citation2]. We also appreciate the opportunity given to us to respond to the points raised by the authors

    Neutron imaging of cadmium sorption and transport in porous rocks

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    Understanding fluid flow in rocks is crucial to quantify many natural processes such as ground water flow and naturally triggered seismicity, as well as engineering questions such as displacement of contaminants, the eligibility of subsurface waste storage, geothermal energy usage, oil and gas recovery and artificially induced seismicity. Two key parameters that control the variability of fluid flow and the movement of dissolved chemical species are (i) the local hydraulic conductivity, and (ii) the local sorption properties of the dissolved chemical species by the solid matrix. These parameters can be constrained through tomography imaging of rock samples subjected to fluid injection under constrained flow rate and pressure. The neutron imaging technique is ideal to explore fluid localization in porous materials due to the high but variable sensitivity of neutrons to the different hydrogen isotopes. However, until recently, this technique was underused in geology because of its large acquisition time. With the improved acquisition times of newly set-up neutron beamlines, it has become easier to study fluid flow. In the current set of experiments, we demonstrate the feasibility of in-situ 2D and 3D time-lapse neutron imaging of fluid and pollutant percolation in rocks, in particular that of cadmium salt. Cadmium is a hazardous compound that is found in many electronic devices, including batteries and is a common contaminant in soil and groundwater. It also exhibits higher contrast in neutron attenuation with respect to heavy water, and is therefore an ideal tracer. Time-lapse 2D radiographies and 3D neutron tomographies of the samples were acquired on two neutron beamlines (ILL, France and SINQ, Switzerland). We performed two sets of experiments, imbibition and injection experiments, where we imaged in-situ flow properties, such as local permeability and interactions between cadmium and the solid rock matrix. Our results indicate that even within these cm-scale porous rocks, cadmium transport follows preferential pathways, and locally interacts within the limestone samples. Our results demonstrate that the use of neutron imaging provides additional insights on subsurface transport of pollutants.Applied Geophysics and Petrophysic
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