Vibrational dynamics of confined granular material

By means of two-dimensional contact dynamics simulations, we analyze the vibrational dynamics of a confined granular layer in response to harmonic forcing. We use irregular polygonal grains allowing for strong variability of solid fraction. The system involves a jammed state separating passive (loading) and active (unloading) states. We show that an approximate expression of the packing resistance force as a function of the displacement of the free retaining wall from the jamming position provides a good description of the dynamics. We study in detail the scaling of displacements and velocities with loading parameters. In particular, we find that, for a wide range of frequencies, the data collapse by scaling the displacements with the inverse square of frequency, the inverse of the force amplitude and the square of gravity. Interestingly, compaction occurs during the extension of the packing, followed by decompaction in the contraction phase. We show that the mean compaction rate increases linearly with frequency up to a characteristic frequency and then it declines in inverse proportion to frequency. The characteristic frequency is interpreted in terms of the time required for the relaxation of the packing through collective grain rearrangements between two equilibrium states

Force transmission in a packing of pentagonal particles

We perform a detailed analysis of the contact force network in a dense confined packing of pentagonal particles simulated by means of the contact dynamics method. The effect of particle shape is evidenced by comparing the data from pentagon packing and from a packing with identical characteristics except for the circular shape of the particles. A counterintuitive finding of this work is that, under steady shearing, the pentagon packing develops a lower structural anisotropy than the disk packing. We show that this weakness is compensated by a higher force anisotropy, leading to enhanced shear strength of the pentagon packing. We revisit "strong" and "weak" force networks in the pentagon packing, but our simulation data provide also evidence for a large class of "very weak" forces carried mainly by vertex-to-edge contacts. The strong force chains are mostly composed of edge-to-edge contacts with a marked zig-zag aspect and a decreasing exponential probability distribution as in a disk packing

Recommandations pour l’utilisation de la toxine botulinique de type A (Botox®) dans l’hyperactivité vésicale réfractaire idiopathique

RésuméObjectifsDéfinir des recommandations pour l’utilisation pratique de la toxine botulinique de type A (BoNTA) dans l’hyperactivité vésicale réfractaire idiopathique (HAVRI).MéthodeÉlaboration de recommandations de bonne pratique par consensus formalisé, validées par un groupe de 13 experts puis par un groupe de lecture indépendant.RésultatsEn cas d’infection urinaire celle-ci doit être traitée et l’injection reportée. Avant l’injection, il est recommandé de s’assurer de la faisabilité et de l’acceptabilité de l’auto-sondage. L’injection peut être réalisée après une anesthésie locale urétro-vésicale (lidocaïne), éventuellement complétée par l’inhalation de protoxyde d’azote et parfois sous anesthésie générale. L’injection sera réalisée au bloc opératoire ou en salle d’endoscopie. La vessie ne doit pas être trop remplie (risque de perforation). Le traitement doit être appliqué en 10 à 20 injections de 0,5 à 1mL réparties de manière homogène dans la vessie en restant à distance des méats urétéraux. Il n’est pas recommandé de laisser en place une sonde vésicale sauf en cas d’hématurie importante. Le patient doit être surveillé jusqu’à la reprise mictionnelle. Une note d’information sur les effets indésirables éventuels doit lui être remise à sa sortie. Une consultation doit être prévue 3 mois après la première injection (calendrier mictionnel, débitmétrie, résidu post-mictionnel et examen cytobactériologique des urines). Un résidu >200mL et/ou symptomatique doit faire discuter des auto-sondages. Une nouvelle injection pourra être envisagée lorsque le bénéfice clinique de la précédente s’estompe (entre 6 et 9 mois).ConclusionsLe respect de ces recommandations devrait permettre une utilisation optimale de la BoNTA.Niveau de preuve3.SummaryObjectivesProvide guidelines for practical usage of botulinum toxin type A (BoNTA) for refractory idiopathic Overactive Bladder management.Patients and methodsGuidelines using formalized consensus guidelines method. These guidelines have been validated by a group of 13 experts quoting proposals, subsequently reviewed by an independent group of experts.ResultsIn the case of patients with urinary tract infection, it must be treated and injection postponed. Before proposing an injection, it is recommended to ensure the feasibility and acceptability of self-catheterisation by patient. The injection can be performed after local anesthesia of the bladder and urethra (lidocaine), supplemented where necessary by nitrous oxide inhalation and sometimes under general anesthesia. Injection is performed in the operating room or endoscopy suite. The bladder should not be too filled (increased risk of perforation). Treatment should be applied in 10 to 20 injections of 0.5 to 1mL homogeneously distributed in the bladder at a distance from the urethral orifices. It is not recommended to leave a urinary catheter in place except in cases of severe hematuria. The patient should be monitored until resumption of micturition. After the first injection, an appointment must be scheduled within 3 months (micturition diary, uroflowmetry, measurement of residual urine and urine culture). Performance of self-catheterisation should be questioned in the case of a symptomatic post-void residual and/or a residue>200mL. A new injection may be considered when the clinical benefit of the previous injection diminishes (between 6 and 9 months). A period of three months must elapse between each injection.ConclusionsImplementation of these guidelines may promote best practice usage of BoNTA with optimal risk/benefit ratio

Institutionalising Kant's political philosophy: Foregrounding cosmopolitan right

There exists a longstanding debate over the global institutional implications of Immanuel Kant's political philosophy: does such a philosophy entail a federal world government, or instead only a confederal ‘league of nations’? However, while the systematic nature of Kant's tripartite ‘doctrine of right' is well recognised, this debate has been conducted with all but exclusive focus on ‘international right' in particular. This article, by contrast, brings ‘cosmopolitan right' firmly into view. It proceeds by way of engagement with the two Kantian arguments made in defence of a ‘league of nations’ in discussion of international right, each of which appeals to aspects of states’ supposed ‘personhood’: the first appeals to states’ distinctive moral personality; the second to states’ physical manifestation. The article considers what happens when we assess these arguments not just in light of the demands of international right, but also in light of cosmopolitan right, and thus in light of public right more comprehensively. The answer is that such arguments cannot succeed as full defences of a league of nations. Indeed, when we assess such arguments with cosmopolitan right in view, they point instead – either tentatively or definitively – in the direction of world government

Radical prostatectomy after vascular-targeted photodynamic therapy (VTP) with TOOKAD® : feasibility, early and intermediate results

Purpose: Vascular targeted photodynamic therapy with TOOKAD® is a new therapeutic option for localized prostate cancer management. The objectives of this study were to assess the feasibility of radical prostatectomy after vascular targeted photodynamic therapy and describe functional and oncologic outcomes. Materials and Methods: We retrospectively included in study 45 patients who underwent salvage radical prostatectomy after vascular targeted photodynamic therapy for recurrent prostate cancer at a total of 14 surgical centers in Europe between October 2008 and March 2017. Of the 42 radical prostatectomies performed 16 were robot-assisted, 6 were laparoscopic and 20 were open surgery. Primary end points were morbidity and technical difficulties. Secondary end points were early and intermediate postoperative functional and oncologic outcomes. Results: Median operative time was 180 minutes (IQR 150-223). Median blood loss was 200 ml (IQR 155-363). According to the surgeons the surgery was easy in 29 patients (69%) and difficult in 13 (31%). Nerve sparing was feasible in 14 patients (33%). Five postoperative complications (12%) were found, including 2 Clavien I, 2 Clavien II and 1 Clavien IIIB complications. Of the cases 13 (31%) were pT3 and 21 (50%) were pT2c. Surgical margins were positive in 13 patients (31%). Prostate specific antigen was undetectable at 6 to 12 months in 37 patients (88%). Nine patients underwent complementary radiotherapy. Four patients had final prostate specific antigen greater than 0.2 ng/ml at a median followup of 23 months (IQR 12-36). At 1 year 27 patients (64%) were completely continent (no pads) and 10 (24%) had low incontinence (1 pad). Four patients (11%) recovered potency without treatment and 23 (64%) recovered potency with appropriate treatment. Conclusions: Salvage radical prostatectomy after vascular targeted photodynamic therapy treatment was feasible and safe without difficulty for most of the surgeons

Engineering Structures A probabilistic approach for estimating the behavior of railway tracks

a b s t r a c t Railway engineering is confronted with problems due to degradation of the rail network that requires important and costly maintenance work. However, because of lack of knowledge on the geometrical and mechanical parameters of the track, it is difficult to optimize maintenance management. In this context, this paper presents a new methodology to analyze the behavior of railway tracks. It combines new diagnostic devices which permit to obtain an important amount of data and thus to make statistics on the geometric and mechanical parameters and a non-intrusive stochastic approach which can be coupled with any mechanical model. Numerical results show the possibilities of this methodology for parametric studies (influence of the distribution and of the correlation of the parameters...). In the future this approach will give important informations to railway managers to optimize maintenance operations