Meromorphic solutions of higher order Briot-Bouquet differential equations

For differential equations $P(y^{(k)},y)=0,$ where $P$ is a polynomial, we prove that all meromorphic solutions having at least one pole are elliptic functions, possibly degenerate

W-superalgebras as truncation of super-Yangians

We show that some finite W-superalgebras based on gl(M|N) are truncation of the super-Yangian Y(gl(M|N)). In the same way, we prove that finite W-superalgebras based on osp(M|2n) are truncation of the twisted super-Yangians Y(gl(M|2n))^{+}. Using this homomorphism, we present these W-superalgebras in an R-matrix formalism, and we classify their finite-dimensional irreducible representations.Comment: Latex, 32 page

Natural oscillations of underactuated cable-driven parallel robots

Underactuated Cable-Driven Parallel Robots (CDPR) employ a number of cables smaller than the degrees of freedom (DoFs) of the end-effector (EE) that they control. As a consequence, the EE is underconstrained and preserves some freedoms even when all actuators are locked, which may lead to undesirable oscillations. This paper proposes a methodology for the computation of the EE natural oscillation frequencies, whose knowledge has proven to be convenient for control purposes. This procedure, based on the linearization of the system internal dynamics about equilibrium con_gurations, can be applied to a generic robot suspended by any number of cables comprised between 2 and 5. The kinematics, dynamics, stability and stiffness of the robot free motion are investigated in detail. The validity of the proposed method is demonstrated by experiments on 6-DoF prototypes actuated by 2, 3, and 4 cables. Additionally, in order to highlight the interest in a robotic context, this modelling strategy is applied to the trajectory planning of a 6-DoF 4-cable CDPR by means of a frequency-based method (multi-mode input shaping), and the latter is experimentally compared with traditional non-frequency-based motion planners

New lipid nanocapsules for decitabine encapsulation

Introduction: Currently decitabine, an antimetabolite agent is approved for acute myeloid leukemia in old patients and is administered via intra-venous (IV) route. It is a harsh treatment characterized by side effects mainly related with the IV administration as pain, risk of infectious, nursing and hospitalization. Oral route may represent a valid alternative route to IV administration because patient convenience and compliance. Due to the quick hydrolyze of the molecule in acidic conditions, decitabine oral bioavailability is very low, it ranges from 3.9 to 14%. The objective of this work was to design and develop a novel formulation to administer the decitabine per os. Material and method: Firstly, decitabine was solubilized in a reverse micelle (RM) formulation based on a mixture of Transcutol® HP and Tween® 80. RM were then incorporated into lipid nanocapsules (LNC-RM) (1).The formulation was then freeze dried and the stability after the freeze drying process was evaluated by comparing the size, the polydispersity index and the zeta potential to the initial values obtained before the freeze drying. The drug paylaod and encapsulation efficiency were determined after an ultracentrifugation to collect the free decitabine and the decitabine loaded in LNC-RM in two different fractions. In vitro release behavior of decitabine from LNC-RM in PBS medium (pH 7.4, 37°C) was evaluated using a dialysis method (Float a Lyzer 100kDa) and compared with the free drug solution. The drug was quantified using LC-MS/MS method. Finally, in vitro permeability study of decitabine-loaded LNC-RM was assessed in a Caco-2 cell model (2). Results and discussion: After freeze drying LNC-RM were stables showing an average size of around 30nm, with a low polydispersity index and a neutral zeta potential. The decitabine payload was 216±57µg/mL, with an encapsulation efficiency of 45±8%. The in vitro release results showed that, after 90min, almost 5% of decitabine was released from the LNC-RM, while the 45% was released from decitabine solution. The apparent permeability was increased when decitabine is encapsulated as compared to the free drug solution in the Caco-2 model after a contact of four hours. Conclusion: Here we presented a new formulation for the oral administration of decitabine. Further studies will be developed to assed the stability of the system in simulated gastro-intestinal media. References: (1) Heurtault B., et al. Pharm Research. 19(6), 2002 (2) Roger E., et al. Eur J Pharm Biopharm. 79(1), 201

Workspace Computation of Planar Continuum Parallel Robots

Continuum parallel robots (CPRs) comprise several flexible beams connected in parallel to an end-effector. They combine the inherent compliance of continuum robots with the high payload capacity of parallel robots. Workspace characterization is a crucial point in the performance evaluation of CPRs. In this paper, we propose a methodology for the workspace evaluation of planar continuum parallel robots (PCPRs), with focus on the constant-orientation workspace. An explorative algorithm, based on the iterative solution of the inverse geometrico-static problem is proposed for the workspace computation of a generic PCPR. Thanks to an energy-based modelling strategy, and derivative approximation by finite differences, we are able to apply the Kantorovich theorem to certify the existence, uniqueness, and convergence of the solution of the inverse geometrico-static problem at each step of the procedure. Three case studies are shown to demonstrate the effectiveness of the proposed approach

Pore Functionalized PVDF Membranes with In-Situ Synthesized Metal Nanoparticles: Material Characterization, and Toxic Organic Degradation

Functionalized PVDF membrane platforms were developed for environmentally benign in-situ nanostructured Fe/Pd synthesis and remediation of chlorinated organic compounds. To prevent leaching and aggregation, nanoparticle catalysts were integrated into membrane domains functionalized with poly (acrylic acid). Nanoparticles of 16–19 nm were observed inside the membrane pores by using focused ion beam (FIB). This technique prevents mechanical deformation of the membrane, compared to the normal SEM preparation methods, thus providing a clean, smooth surface for nanoparticles characterization. This allowed quantification of nanoparticle properties (size and distribution) versus depth underneath the membrane surface (0–20 μm). The results showed that nanoparticles were uniformly sized and evenly distributed inside the membrane pores. However, the size of nanoparticles inside the membrane pores was 13.9% smaller than those nanoparticles located on the membrane surface. Investigating nanoparticles inside membrane pores increases the accuracy of kinetic analysis and modeling aspects. Furthermore, the Fe/Pd immobilized membranes showed excellent performance in the degradation of chlorinated organics: Over 96% degradation of 3,3\u27,4,4\u27,5-pentachlorobiphenyl (PCB 126) was achieved in less than 15 s residence time in convective flow mode. The regeneration and reuse of this catalytic membrane system were also studied. Particles were examined in XRD upon formation, after deliberate oxidation, and after regeneration. The regenerated sample showed the same crystalline pattern as the original sample. Repeated degradation experiments demonstrated successful PCB 126 dechlorination with nanoparticles regenerated for four cycles with only a small loss in reactivity. It demonstrated that Fe/Pd immobilized membranes have the potential for large-scale remediation applications

Decitabine encapsulation in nanovector to improve acute myeloid leukemia treatment

Acute myeloid leukemia (AML) mainly affects adult patients, and for older ones unfit for intensive chemotherapy only few therapies are available. Hypomethylating agents, as decitabine, is a labeled option but its plasma half-life is short whereas a long cell exposure time improves response rate. Only intravenous administration is available, whereas an oral route is generally preferred by patients. Consequently, to enhance plasma half-life and to develop an oral decitabine formulation, in this work decitabine was encapsulated in nanoparticles. Two different strategies were tested: decitabine loaded into lipid nanocapsules (DAC-LNC), and a decitabine-prodrug synthesis [3’(OH)-5’(OH)-(lauroyl)2-modified DAC] encapsulated into LNC (DAC-(C12)2-LNC). DAC-LNC and DAC-(C12)2-LNC particles were obtained with sizes of 26.5 ± 0.5 nm and 27.45 ± 0.05 nm respectively, and drug payloads of 0.47 ± 0.06 mg/mL and 5.8 ± 0.5 mg/mL (corresponding to 2.3 ± 0.2 mg/mL of decitabine). Both formulations were able to increase in vitro human plasma half-life by protecting decitabine from degradations. Compared to free-decitabine solutions, both nanoparticle formulations were able to preserve decitabine cytotoxicity on an AML cell line (HEL). Moreover, permeability studies across an adenocarcinoma cell model (Caco-2 cells) demonstrated that DAC-LNC improve decitabine’s intestinal permeability whereas DAC-(C12)2-LNC decreased it. However, this drawback could be countered by the enhanced decitabine’s stability in gastrointestinal fluids thanks to DAC-(C12)2-LNC, leading to more available drug for absorption. Globally, both formulation have demonstrated their ability to improve DAC plasma half-life in vitro and their potential for oral administration. In vivo pharmacokinetics evaluations may now confirm interests of such strategies