Proton conductivity of multifunctional metal phosphonate frameworks

Metal phosphonates exhibit attractive characteristics for proton conductivity, such as tunable functionality, chemical and thermal stability and the existence of H-bond networks with acidic protons within their structure.1 In the present work, we examine the relationship between crystal structure and proton conductivity for several metal (mono-, di- and tri-valent) phosphonates containing rigid: (5-(dihydroxyphosphoryl)isophthalic acid, PiPhtA and 2-hydroxyphosphonoacetic acid, HPAA) or flexible: (hexa- or octamethylenediamine-N,N,N′,N′-tetrakis(methylenephosphonic acid, H8HDTMP or H8ODTMP) multifunctional ligands. The crystalline hybrid derivatives prepared show a great structural diversity, from 1D to 3D open-frameworks possessing hydrogen-bonded water molecules and phosphonic and carboxylic acid groups. The rigid 3D framework of Ca-PiPhtA, that exhibits a proton conductivity of 5.7•10-4 S/cm as synthesized, transforms into a layered compound upon exposure to ammonia vapors2 with increased proton conductivity (6.6•10-3 S/cm). The flexible frameworks of magnesium or lanthanide phosphonates, with 1D channels, present conductivities higher than 10-3 S/cm. Their activation energies fall in the range corresponding to a Grotthuss mechanism.3,4 For M(I)-HPAA solids conductivities up to 5.6•10-3 S/cm were measured. References 1. P. Ramaswamy, N.E. Wong, G.K.H. Shimizu, Chem. Soc. Rev. 43 (2014) 5913. 2. M. Bazaga-García, R.M.P. Colodrero, M. Papadaki, P. Garczarek, J. Zoń, P. Olivera-Pastor, E.R. Losilla, L. León-Reina, M.A.G. Aranda, D. Choquesillo-Lazarte, K.D. Demadis, A. Cabeza, J. Amer. Chem. Soc. 136 (2014) 5731. 3. R.M.P. Colodrero, P. Olivera-Pastor, E.R. Losilla, D. Hernández-Alonso, M.A.G. Aranda, L. Leon-Reina, J. Rius, K.D. Demadis, B. Moreau, D. Villemin, M. Palomino, F. Rey, A. Cabeza, Inorg. Chem. 51 (2012) 7689. 4. R.M.P. Colodrero, P. Olivera-Pastor, E.R. Losilla, M.A.G. Aranda, L. Leon-Reina, M. Papadaki, A.C. McKinlay, R.E. Morris, K.D. Demadis, A. Cabeza, Dalton Trans. 41 (2012) 4045.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Junta de Andalucía, Proyecto Excelencia FQM-1656. Ministerio de Economía y Competitividad, MAT2013-41836-

Structural Variability in Multifunctional Metal Xylenediaminetetraphosphonate Hybrids

The two cornerstones in the field of MOFs are the Secondary Building Units (SBU’s or “bricks”) and the organic linkers. The structural tunability of crystalline MOFs coupled, when possible, with high chemical and thermal robustness, makes them suitable materials to correlate structure with function [1]. Hence, the research focus has been set recently to the potential applications of some of these compounds, including phosphonate-based MOFs [2]. We report two families of isostructural divalent (Ca, Mg, Co, Zn) hybrid phosphonate MOFs based on the tetraphosphonate ligands 1,4- and 1,3-bis(aminomethyl)benzene-N,N’-bis(methylenephosphonic acid), (H2O3PCH2)2-N- CH2C6H4CH2-N(CH2PO3H2)2, (designated as p-C12H20O12N2P4•or m-C12H20O12N2P4, respectively). The use of these two functionalized ligands, otherwise chemically and structurally quite similar, represents a good example of how small stereochemical changes in the organic linker may dramatically affect structural features and dimensionality of the resulting solids and, hence, their final properties. The crystal structures of representative compounds of each family were solved ab initio from synchrotron powder diffraction data (λ=0.2998 Å, beamline ID31-ESRF) and were used as starting models for the Rietveld refinements of the remaining components. M-p-C12H20O12N2P4 (M = Mg, Co and Zn) present low dimensionality (1D) within a wide range of experimental conditions (figure 1). In contrast, solids containing the linker m-H8L, M-m-C12H20O12N2P4 (M = Mg, Ca and Zn) tend to acquire a 3D pillared open-framework for a wide range of metal ion sizes (figure 2). Two representative members, Mg-p-C12H20O12N2P4 and Zn-m-C12H20O12N2P4, were studied for characterizing their proton-conducting behavior. At 98 % RH and T = 297 K, σ are close to 9.4x10-5 Sxcm-1 for both compounds [3]. Their crystal structures, thermal stability and proton conductivity properties will be reported and discussed.Proyecto MAT2010-15175, grupo PAIDI FQM-11

In situ high pressure powder diffraction study of proton conductors based on metal phosphonates

Soft Porous Metal Organic frameworks (MOFs) are referred to as a class of coordination polymers that exhibit structural flexibility in response to guest interactions or physical stimuli [1]. By combining softness and regularity, the responsive crystalline frameworks show, for instance, unique mechanisms of separation and storage of gases. Here we report the effects of high pressures of CO2 on the frameworks of two types of coordination polymers based on multifunctional metal phosphonates, which exhibit proton conductivity at high relative humidity in addition to porous properties. The first one, Ni2(H2O)2(O3PCH2N(C4H8)NCH2PO3)⋅8H2O (Ni-STA-12) is a well-known MOF material structural featured by 1D channels build from MO5N octahedra linked by the piperazinyl moieties [2]. The second solid, Mg[(HO3PCH2)2NHCH2C6H4CH2NH-(CH2PO3H)2]·2H2O, (MgHDTMP·2H2O), is a pillared layer metal phosphonate containing flexible alkyldiaminetetraphosphonate as linker of the inorganic layers. For both solids, in situ synchrotron powder diffraction data were collected on BL04-MSPD under different pressures of CO2 (up to ~10 bar) and temperatures at ALBA (Barcelona, Spain). The resulting structural changes observed on their frameworks as well as their proton conductivities will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Junta de Andalucía,Proyecto de Excelencia P12-FQM-1656 MINECO: MAT2013-41836-R

Dynamics of Entanglement in One-Dimensional Spin Systems

We study the dynamics of quantum correlations in a class of exactly solvable Ising-type models. We analyze in particular the time evolution of initial Bell states created in a fully polarized background and on the ground state. We find that the pairwise entanglement propagates with a velocity proportional to the reduced interaction for all the four Bell states. Singlet-like states are favored during the propagation, in the sense that triplet-like states change their character during the propagation under certain circumstances. Characteristic for the anisotropic models is the instantaneous creation of pairwise entanglement from a fully polarized state; furthermore, the propagation of pairwise entanglement is suppressed in favor of a creation of different types of entanglement. The ``entanglement wave'' evolving from a Bell state on the ground state turns out to be very localized in space-time. Further support to a recently formulated conjecture on entanglement sharing is given.Comment: 25 pages, 21 figures; revte

Pumping spin with electrical fields

Spin currents can be obtained through adiabatic pumping by means of electrical gating only. This is possible by making use of the tunability of the Rashba spin-orbit coupling in semiconductor heterostructures. We demonstrate the principles of this effect by considering a single-channel wire with a constriction. We also consider realistic structures, consisting of several open channels where subband spin-mixing and disorder are present, and we confirm our predictions. Two different ways to detect the spin-pumping effect, either using ferromagnetic leads or applying a magnetic field, are discussed.Comment: 5 pages, 2 figures; minor changes, typos correcte

Cost-effectiveness of robot-assisted radical cystectomy vs open radical cystectomy for patients with bladder cancer

Importance The value to payers of robot-assisted radical cystectomy with intracorporeal urinary diversion (iRARC) when compared with open radical cystectomy (ORC) for patients with bladder cancer is unclear. Objectives To compare the cost-effectiveness of iRARC with that of ORC. Design, Setting, and Participants This economic evaluation used individual patient data from a randomized clinical trial at 9 surgical centers in the United Kingdom. Patients with nonmetastatic bladder cancer were recruited from March 20, 2017, to January 29, 2020. The analysis used a health service perspective and a 90-day time horizon, with supplementary analyses exploring patient benefits up to 1 year. Deterministic and probabilistic sensitivity analyses were undertaken. Data were analyzed from January 13, 2022, to March 10, 2023. Interventions Patients were randomized to receive either iRARC (n = 169) or ORC (n = 169). Main Outcomes and Measures Costs of surgery were calculated using surgery timings and equipment costs, with other hospital data based on counts of activity. Quality-adjusted life-years were calculated from European Quality of Life 5-Dimension 5-Level instrument responses. Prespecified subgroup analyses were undertaken based on patient characteristics and type of diversion. Results A total of 305 patients with available outcome data were included in the analysis, with a mean (SD) age of 68.3 (8.1) years, and of whom 241 (79.0%) were men. Robot-assisted radical cystectomy was associated with statistically significant reductions in admissions to intensive therapy (6.35% [95% CI, 0.42%-12.28%]), and readmissions to hospital (14.56% [95% CI, 5.00%-24.11%]), but increases in theater time (31.35 [95% CI, 13.67-49.02] minutes). The additional cost of iRARC per patient was £1124 (95% CI, −£576 to £2824 [US $1622 (95$831 to $4075)]) with an associated gain in quality-adjusted life-years of 0.01124 (95$144 312) per quality-adjusted life-year gained. Robot-assisted radical cystectomy had a much higher probability of being cost-effective for subgroups defined by age, tumor stage, and performance status. Conclusions and Relevance In this economic evaluation of surgery for patients with bladder cancer, iRARC reduced short-term morbidity and some associated costs. While the resulting cost-effectiveness ratio was in excess of thresholds used by many publicly funded health systems, patient subgroups were identified for which iRARC had a high probability of being cost-effective

Robot Axis Dynamics Control Using A Virtual Robotics Environment

Robots are complex electromechanical systems where several electric drives are employed to control the movement of articulated structures. In industrial environments they must perform tasks with rapidity and accuracy in order to produce goods and services with minimal production time. These procedures require the use of flexible robots which can act in a large workspace, thus subject to important parameters variations, with efficient control algorithms. The progress of technology and the close relationships among several sciences, such as micro-electronic, software engineering and communications, open space for a great development in the robotics area and automation process. Generalized Predictive Control (GPC) has shown to be an effective strategy in many fields of applications, with good time-domain and frequency properties (small overshoot, improved tracking accuracy and disturbance rejection ability, good stability and robustness margins), able to cope with important parameters variations. This paper presents an application of GPC to a robot trajectory control with a comparison between classical PID and GPC controllers within an original Virtual Environment. © 2005 IEEE.1 2 VOLS305311Boucher, P., Dumur, D., Predictive Motion Control (1995) Journal of Systems Engineering, Special Issue on Motion Control Systems, 5, pp. 148-162. , Springer-Verlag, LondonSpong, M.W., Vidyasagar, M., Robot Dynamics and Control (1989) John Wiley & Sons, , New YorkClarke, D.W., Mohtadi, C., Tuffs, P.S., Generalized Predictive Control", Part I "The Basic Algorithm", Part II "Extensions and Interpretation (1987) Automatica, 23 (2), pp. 137-160Craig, J.J., (1989) Introduction to Robotics: Mechanics and Control, , Second edition, Addison-Wesley Publishing CompanyDavid, S., Rosário, J.M., Modeling, Simulation and Control of Flexible Robots (1998) CONTROLO'98, pp. 532-539. , Coimbra, PortugalPimenta, K.B., Souza, J.P., Rosário, J.M., Dumur, D., Control of Robotic Joints with Generalized Predictive Control (GPC) (2001) RADD '2001, , Vienne, AustriaPimenta, K.B., Rosário, J.M., The Using Techniques of Generalized Predictive Control (GPC) Applied on Control of Robotic Joints (2001) Asiar, , Bangkok, ThailandRosário, J.M., Oliveira, C., Sa, C.E.A., Proposal Methodology for the Modeling and Control of Manipulators (2002) International Journal of the Brazilian Society of Mechanical Engineering, XXIV-N. , 3, Jul

A 3 DOF robotic platform dynamics control using rapid prototyping tools

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