From large-scale to micro machining: a review of force prediction models

International audienceIn this paper, a reviewof work performed in the area of force modelling in metal cutting processes is presented. Past and present trends are described and criticised to compare their relevance with current requirements. Several approaches are reviewed, such as empirical, mechanistic and analytical models. The models' ability to predict forces, from rough machining to finish machining, is analysed

Early and long-term outcomes following long posterior flap vs. skew flap for below knee amputations

Objective To compare outcomes between long posterior flap (LPF) and skew flap (SF) amputation over a 13 year period. Methods This was a retrospective observational cohort study. Consecutive patients undergoing a LPF or SF below knee amputation (BKA) over a 13 year period at one hospital were identified. Both techniques were performed regularly, depending on tissue loss and surgeon preference. The primary outcome was surgical revision of any kind. Secondary outcomes included revision to above knee amputation (AKA), length of hospital stay (LOS), and mortality. A smaller cohort of patients who were alive and unilateral below knee amputees were contacted to ascertain prosthetic use and functional status. Results In total, 242 BKAs were performed in 212 patients (125 LPF and 117 SF; median follow up 25.8 months). Outcomes for the two groups were equivalent for surgical revision of any kind (27 LPF vs. 31 SF; p = .37), revision to an AKA (18 LPF vs. 14 SF; p = .58), LOS (29 days for LPF vs. 28 days for SF; p = .83), and median survival (23.9 months for LPF vs. 28.8 months for SF; p = .89). Multivariable analysis found amputation type had no effect on any outcome. Functional scores from a smaller cohort of 40 unilateral amputees who were contactable demonstrated improved outcomes with the LPF vs. the SF (p = .038). Conclusion Both techniques appear equivalent for rates of surgical residual limb failure. Functional outcomes may be better with the LPF

Identifying barriers to gene flow and hierarchical conservation units from seascape genomics : a modelling framework applied to a marine predator

The ongoing decline of large marine vertebrates must be urgently mitigated, particularly under increasing levels of climate change and other anthropogenic pressures. However, characterizing the connectivity among populations remains one of the greatest challenges for the effective conservation of an increasing number of endangered species. Achieving conservation targets requires an understanding of which seascape features influence dispersal and subsequent genetic structure. This is particularly challenging for adult-disperser species, and when distribution-wide sampling is difficult. Here, we developed a two-step modelling framework to investigate how seascape features drive the genetic connectivity of marine species without larval dispersal, to better guide the design of marine protected area networks and corridors. We applied this framework to the endangered grey reef shark, Carcharhinus amblyrhynchos, a reef-associated shark distributed across the tropical Indo-Pacific. In the first step, we developed a seascape genomic approach based on isolation-by-resistance models involving circuit theory applied to 515 shark samples, genotyped for 4991 nuclear single-nucleotide polymorphisms. We show that deep oceanic areas act as strong barriers to dispersal, while proximity to habitat facilitates dispersal. In the second step, we predicted the resulting genetic differentiation across the entire distribution range of the species, providing both local and global-scale conservation units for future management guidance. We found that grey reef shark populations are more fragmented than expected for such a mobile species, raising concerns about the resilience of isolated populations under high anthropogenic pressures. We recommend the use of this framework to identify barriers to gene flow and to help in the delineation of conservation units at different scales, together with its integration across multiple species when considering marine spatial planning.Peer reviewe

Tidal Energy Round Robin Tests: A Comparison of Flow Measurements and Turbine Loading

A Round Robin Tests program is being undertaken within the EC MaRINET2 initiative. This programme studies the used facility influence can have on the performance evaluation of a horizontal axis tidal turbine prototype when it is operated under wave and current conditions. In this paper, we present the design of experiments that is used throughout the work programme and the results related to the flow characterisation obtained at the Ifremer wave and current circulating tank, the Cnr-Inm wave towing tank and the ocean research facility FloWave. These facilities have been identified to provide adequate geometric conditions to accommodate a 0.724 m diameter turbine operating at flow velocities of 0.8 and 1.0 m/s. The set-up is replicated in each of the facilities with exemption of the amount of flow measuring instruments. Intrinsic differences in creating wave and currents between facilities are found. Flow velocities are up to 10% higher than the nominal values and wave amplitudes higher than the target values by up to a factor of 2. These discrepancies are related to the flow and wave generation methods used at each facility. When the flow velocity is measured besides the rotor, the velocity presents an increase of 8% compared to the upstream measurements

Anxiolytic - like properties of Hallea ciliata in mice

Background: The aim of the present study was to evaluate the anxiolytic properties of the decoction of stem bark of Hallea ciliate in mice. The decoction of Hallea ciliata is used in traditional medicine in Cameroon to treat diseases like anxiety disorders, fever, infantile convulsions and malaria.Materials and Methods: Stress induced hyperthermia, elevated plus maze, open field and hole-board tests were used. Four different doses of the decoction were administered to mice and their effects were compared to the effects of diazepam and vehicle. Phytochemical characterization of the decoction revealed the presence of alkaloids, flavonoids, tannins and saponins.Results: Administration of Hallea ciliata resulted in a significant decrease of stress induced hyperthermia in mice at the doses of 29.5, 59 and 118 mg/kg. In the elevated plus maze test, Hallea ciliata increased the number of entries and the percentages of entries and time into the open arms, and reduced the number of entries and the percentages of entries and time into the closed arms. In the  hole-board test, Hallea ciliata increased the number of both head-dipping and crossing and decreased the latency to the first head-dips and rearing. The decoction of Hallea ciliata and diazepam increased locomotion in the open field test.Conclusion: The number of rearing and the mass of fecal boli produced were decreased in mice treated with decoction and diazepam. In conclusion, the results indicated that decoction of Hallea ciliata has anxiolytic-like properties in mice and could potentially be used for anxiety treatment.Key words: anxiety, herbs, pharmacology, diazepa

Analysis of the effects of control strategies and wave climates on the loading and performance of a laboratory scale horizontal axis tidal turbine

To understand the influence of complex hydrodynamic loads on tidal turbines, laboratory testing is necessary as a first approach. Previous laboratory work undertaken gave an indication that the use of speed control strategies may disguise the associated loading range that a turbine may be subjected to when this is operated with a variable speed control strategy. However, the preceding work was undertaken in a highly controlled environment without the influence of turbulent flows. The focus of this paper is directed towards the study of wave-induced loads on tidal turbines when these are controlled using two strategies and the impact that these parameters have on the turbine's performance when this is operated in a recirculating flume. Laboratory tests were undertaken with a 0.9 m diameter horizontal axis tidal turbine subjected to combined wave and current conditions with both regular and irregular waves. Constant speed and constant torque control strategies have been considered, for which rotor thrust, torque and blade root bending moment have been measured. Results show that similar to previous studies, average loads and power capture values remain unchanged between control strategies and the superposition of waves to the current. However, signal fluctuations are 2 to 3 times higher for torque control than for constant speed control strategy. A phase difference between the periodic signals of the turbine thrust and the incoming waves was also identified, in this case, the phase variation was lower when using torque than speed control. This work thus demonstrates the implication of studying strategies to control a marine converter from early stages of development

ANXIOLYTIC - LIKE PROPERTIES OF HALLEA CILIATA IN MICE

Background: The aim of the present study was to evaluate the anxiolytic properties of the decoction of stem bark of Hallea ciliata in mice. The decoction of Hallea ciliata is used in traditional medicine in Cameroon to treat diseases like anxiety disorders, fever, infantile convulsions and malaria. Materials and Methods: Stress induced hyperthermia, elevated plus maze, open field and hole-board tests were used. Four different doses of the decoction were administered to mice and their effects were compared to the effects of diazepam and vehicle. Phytochemical characterization of the decoction revealed the presence of alkaloids, flavonoids, tannins and saponins. Results: Administration of Hallea ciliata resulted in a significant decrease of stress induced hyperthermia in mice at the doses of 29.5, 59 and 118 mg/kg. In the elevated plus maze test, Hallea ciliata increased the number of entries and the percentages of entries and time into the open arms, and reduced the number of entries and the percentages of entries and time into the closed arms. In the hole-board test, Hallea ciliata increased the number of both head-dipping and crossing and decreased the latency to the first headdips and rearing. The decoction of Hallea ciliata and diazepam increased locomotion in the open field test. Conclusion: The number of rearing and the mass of fecal boli produced were decreased in mice treated with decoction and diazepam. In conclusion, the results indicated that decoction of Hallea ciliata has anxiolytic-like properties in mice and could potentially be used for anxiety treatment

ANTIOXIDANT PROPERTIES OF DICHROCEPHALA INTEGRIFOLIA (ASTERACEAE) IN A MOUSE MODEL OF MONOSODIUM GLUTAMATE-INDUCED NEUROTOXICITY

Background: In Africa, neurodegenerative diseases in the elderly have become a major health concern due to the increase in live expectancy. Glutamate mediated neurotoxicity is involved in neurodegenerative diseases such as Ischemia, Epilepsy, Alzheimer’s and Parkinson diseases. Plants with antioxidant properties are reported to protect vital organs against glutamate toxicity. This study aims to assess the effect of Dichrocephala integrifolia against monosodium glutamatemediated neurotoxicity and oxidative stress. Methodology: The decoction prepared from the leaves of Dichrocephala integrifolia was evaluated against monosodium glutamate-induced neurotoxicity in mice. The animals were grouped in seven groups of 6 animals each. The animals received daily; distilled water (p.o) for the distilled water and the negative control groups, one of the four doses of the decoction of the plant (35, 87.5, 175 or 350 mg/kg p.o) for the tests groups and memantine (20 mg/kg p.o) for the positive control group. Monosodium glutamate (2.5 g/kg ip) was injected daily to animals except those of the normal control group all the seven days of the experimentation. Animals were observed for aggressiveness, locomotor and forepaws muscle grip activities 30 min after monosodium injections. Brain reduced glutathione and malondialdehyde levels were also assessed following the behavioral tests on day 8. Results: The decoction of Dichrocephala integrifolia at the doses of 87.5 and 175 mg/kg significantly (

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London