Sobre las diferentes nociones topológicas de complejo y algunas de sus aplicaciones

The main goal of this work is to introduce the different kinds of combinatorial structures used in topological data analysis. It is focused on a detailed description of certain types of simplicial, cubical and cellular complexes, namely flag complexes, Cech complexes, Vietoris-Rips complexes, Witness complexes, Delaunay complexes and Alpha complexes will be considered. Additionally, persistent homology will be introduced as the main tool to extract relevant topological information from data sets via the above mentioned kinds of complexes.Universidad de Sevilla. Grado en Matemática

Mechanical assessment of novel compliant mechanisms for underactuated prosthetic hands

This paper proposes novel compliant mechanisms for constructing hand prostheses based on soft robotics. Two models of prosthetic hands are developed in this work. Three mechanical evaluations are performed to determine the suitability of the two designs for carrying out activities of daily living (ADLs). The first test measures the grip force that the prosthesis can generate on objects. The second determines the energy required and dissipated from the prosthesis to operate. The third test identifies the maximum traction force that the prosthesis can support. The tests showed that the PrHand1 prosthesis has a maximum grip force of 23.38 ± 1.5 N, the required energy is 0.76 ± 0.13 J, and the dissipated energy is 0.21 ± 0.17 J. It supports a traction force of 173.31 ± 5.7 N. The PrHand2 prosthesis has a maximum grip force of 36.13 ± 2.3 N, the required energy is 1.28 ± 0.13 J, the dissipated energy is 0.96 ± 0.12 J, and it supports a traction force of 78.48 ± 0 N. In conclusion, the PrHand1 prosthesis has a better performance in terms of energy and tensile force supported. The difference between the energy and traction force results is related to two design features of the PrHand2: fully silicone-coated fingers and a unifying mechanism that requires more force on the tendons to close the prosthesis. The grip force of the PrHand2 prosthesis was more robust than the PrHand1 due to its silicone coating, which allowed for an improved grip

The role of immune checkpoints in cardiovascular disease

Immune checkpoint inhibitors (ICI) are monoclonal antibodies which bind to immune checkpoints (IC) and their ligands to prevent inhibition of T-cell activation by tumor cells. Currently, multiple ICI are approved targeting Cytotoxic T-lymphocyte antigen 4 (CTLA-4), Programmed Death Protein 1 (PD-1) and its ligand PD-L1, and Lymphocyte-activation gene 3 (LAG-3). This therapy has provided potent anti-tumor effects and improved prognosis for many cancer patients. However, due to systemic effects, patients can develop immune related adverse events (irAE), including possible life threatening cardiovascular irAE, like atherosclerosis, myocarditis and cardiomyopathy. Inhibition of vascular IC is associated with increased atherosclerotic burden and plaque instability. IC protect against atherosclerosis by inhibiting T-cell activity and cytokine production, promoting regulatory T-cell differentiation and inducing T-cell exhaustion. In addition, PD-L1 on endothelial cells might promote plaque stability by reducing apoptosis and increasing expression of tight junction molecules. In the heart, IC downregulate the immune response to protect against cardiac injury by reducing T-cell activity and migration. Here, inhibition of IC could induce life-threatening T-cell-mediated-myocarditis. One proposed purpose behind lymphocyte infiltration is reaction to cardiac antigens, caused by decreased self-tolerance, and thereby increased autoimmunity because of IC inhibition. In addition, there are several reports of ICI-mediated cardiomyopathy with immunoglobulin G expression on cardiomyocytes, indicating an autoimmune response. IC are mostly known due to their cardiotoxicity. However, t his review compiles current knowledge on mechanisms behind IC function in cardiovascular disease with the aim of providing an overview of possible therapeutic targets in prevention or treatment of cardiovascular irAEs

Inverse magnetorheological fluids

We report a new kind of field-responsive fluids consisting of suspensions of diamagnetic (DM) and ferromagnetic (FM) microparticles in ferrofluids. We designate them as inverse magnetorheological (IMR) fluids for analogy with inverse ferrofluids (IFFs). Observations on the particle self-assembly in IMR fluids upon magnetic field application showed that DM and FM microparticles were assembled into alternating chains oriented along the field direction. We explain such assembly on the basis of the dipolar interaction energy between particles. We also present results on the rheological properties of IMR fluids and, for comparison, of IFFs and bidispersed magnetorheological (MR) fluids. Interestingly, we found that upon magnetic field, the rheological properties of IMR fluids were enhanced with respect to bidispersed MR fluids with the same FM particle concentration, by an amount greater than the sum of the isolated contribution of DM particles. Furthermore, the field-induced yield stress was moderately increased when up to 30 % of the total FM particle content was replaced with DM particles. Beyond this point, the dependence of the yield stress on the DM content was non-monotonic, as expected for FM concentrations decreasing to zero. We explain these synergistic results by two separate phenomena: the formation of exclusion areas for FM particles due to the perturbation of the magnetic field by DM particles, and the dipole-dipole interaction between DM and FM particles, which enhances the field-induced structures. Based on this second phenomenon, we present a theoretical model for the yield stress that semi-quantitatively predicts the experimental results.Projects 12-01-00132, 13-02-91052, 13-01-96047, 14-08-00283 (Russian Fund of Fundamental Investigations), 2.1267.2011 (Ministry of Education of Russian Federation), the Act 211 (Government of the Russian Federation № 02.A03.21.0006). The University of Granada (Acción Integrada con Rusia; Plan Propio 2011). L. Rodríguez-Arco acknowledges financial support by Secretaría de Estado de Educación, Formación Profesional y Universidades (MECD, Spain) through its FPU program

Stability behaviour of composite magnetorheological fluids by an induction method

Este artículo puede consultarse en la siguiente dirección de la editorial: http://jim.sagepub.com/content/early/2015/03/26/1045389X15577656.full.pdf+htmlIn this work we study the stability behaviour of composite magnetorheological (MR) fluids consisting of magnetic (iron) and non-magnetic (poly (methylmethacrylate), PMMA) particles dispersed in mineral oil. Because of the opacity of the suspensions, optical methods traditionally employed for evaluation of the gravitational settling in colloidal suspensions are not suitable for sedimentation follow-up in this case. For this reason, we use an alternative method based on the evaluation of the resonant frequency of the inductance of a thin coil surrounding the sample The movement of the coil along the height of the container at specified steps and time intervals allows obtaining information about the local volume fraction of particles inside the tube. The obtained successive profiles for the multi-component suspensions show a decrease of the iron particle settling and of the initial rate of settling as the PMMA volume fraction is increased. Finally, the increase of the PMMA concentration gives rise to an improvement of the rheological properties upon magnetic field application for a given concentration of iron. Both a strongrheological response and a good colloidal stability are essential for practical applications.Proyectos PE2012-FQM694 (Junta de Andalucía, Spain)y FIS2013-47666-C3-1-R (Ministerio de Economía y Competitividad, Spain). L. R.-A. agrradece a la Universidad de Granada su contrato puente (Plan Propio de Investigación, UGR)

Self-assembly in magnetic supramolecular hydrogels

Most recent advances in the synthesis of supramolecular hydrogels based on low molecular weight gelators (LMWGs) have focused on the development of novel hybrid hydrogels, combining LMWGs and different additives. The dynamic nature of the noncovalent interactions of supramolecular hydrogels, together with the specific properties of the additives included in the formulation, allow these novel hybrid hydrogels to present interesting features, such as stimuli-responsiveness, gel-sol reversibility, self-healing and thixotropy, which make them very appealing for multiple biomedical and biotechnological applications. In particular, the inclusion of magnetic nanoparticles in the hydrogel matrix results in magnetic hydrogels, a particular type of stimuli-responsive materials that respond to applied magnetic fields. This review focuses on the recent advances in the development of magnetic supramolecular hydrogels, with special emphasis in the role of the magnetic nanoparticles in the self-assembly process, as well as in the exciting applications of these materials

Mechanical assessment of novel compliant mechanisms for underactuated prosthetic hands

This paper proposes novel compliant mechanisms for constructing hand prostheses based on soft robotics. Two models of prosthetic hands are developed in this work. Three mechanical evaluations are performed to determine the suitability of the two designs for carrying out activities of daily living (ADLs). The first test measures the grip force that the prosthesis can generate on objects. The second determines the energy required and dissipated from the prosthesis to operate. The third test identifies the maximum traction force that the prosthesis can support. The tests showed that the PrHand1 prosthesis has a maximum grip force of 23.38 ± 1.5 N, the required energy is 0.76 ± 0.13 J, and the dissipated energy is 0.21 ± 0.17 J. It supports a traction force of 173.31 ± 5.7 N. The PrHand2 prosthesis has a maximum grip force of 36.13 ± 2.3 N, the required energy is 1.28 ± 0.13 J, the dissipated energy is 0.96 ± 0.12 J, and it supports a traction force of 78.48 ± 0 N. In conclusion, the PrHand1 prosthesis has a better performance in terms of energy and tensile force supported. The difference between the energy and traction force results is related to two design features of the PrHand2: fully silicone-coated fingers and a unifying mechanism that requires more force on the tendons to close the prosthesis. The grip force of the PrHand2 prosthesis was more robust than the PrHand1 due to its silicone coating, which allowed for an improved grip

Pressure and angle sensors with optical fiber for instrumentation of the PrHand hand prosthesis

The principal cause of upper limb amputations is due to traumatism. The prosthesis is an assistive device to help in the activities of daily for the amputee person. However, one of the latest reports shows that in developing countries there are around 30 million people without assistive devices. This work presents the development of two kinds of sensors for the PrHand, an upper limb prosthesis based on compliant mechanism and soft-robotics. The sensors are made with polymeric optical fiber (POF), due to their flexibility and low cost, and the working principle is based on intensity variation. The angle sensors are used for monitoring the interphalangeal joint of the fingers, and for the assessment were made cycles of closing and opening each finger. On the other hand, the force sensors are located at the tip of three fingers to track the force made over the objects. Before encoring the sensors were evaluated making five cycles of compressing and decompressing each sensor. The results show a linear behavior between the angle and the voltage variation, one most remarkable angle sensor result was with a sensibility of 0.0357 V/° and an R2 of 99 % closing and 0.0483 V/° opening. In the case of the force sensor, a polynomial relation was found between the voltage changes and the pressure over the sensor; in some cases, the relation between voltage changes and pressure could be linear but that depends on the construction of the sensor. Regarding the obtained R2 of 99 %, its sensibility was 0.0361 V/N compression and 0.0368 V/N decompression. In conclusion, was successfully developed two kinds of sensors for the instrumentation of PrHand prosthesis. It is expected to use angle and sensor variables as input in algorithms of Machine Learning to improve the detection of objects. One aspect to improve is to control in a better way the sensor construction parameters due to the considerable influence over the sensor behavior

Analisis Optimasi Produksi Sumur Gas Lift Lapangan Awiligar dengan Perbandingan Desain Ulang dan Konversi Esp

Sumur minyak yang berproduksi akan mengalami penurunan produksi dikarenakan turunnya tekanan formasi sehingga dibutuhkan pengangkatan buatan.Sumur – sumur pada Lapangan Awiligar sebagian besar berproduksi dengan pengangkatan buatan gas lift. Lapangan Awiligar bertujuan meningkatkan produksi harian, sehingga perlu dilakukan optimasi diantaranya optimasi sumur – sumur gas lift. Sumur gas lift yang dikaji adalah Sumur M-150, Sumur – M-155, Sumur M-160, dan Sumur M-165 karena water cut yang tidak terlalu tinggi diantara sumur gas lift lainnya dan produksi yang lebih tinggi dari sumur gas lift lainnya.Optimasi dilakukan dengan perbandingan antara menambah jumlah laju injeksi gas, mendesain ulang posisi katup, dan menkonversi menjadi Electric Submersible Pump (ESP) dimana skenario terbaik dilihat dari lifting cost terkecil. Hasil skenario terbaik untuk optimasi sumur kajian adalah dengan konversi menjadi ESP dikarenakan produksi yang lebih besar dan lifting cost yang lebih rendah dari gas lift

Hair cortisol concentrations in a Spanish sample of healthy adults

Hair cortisol concentration (HCC), as a novel promising method to retrospectively measure hypothalamic-pituitary-adrenal (HPA) axis activation, is being increasingly studied. We tested the relationships between HCC and a range of possible confounding variables in a Spanish sample of healthy adults and pregnant women. In this sample of healthy Spaniards, results suggested an association between HCC and physical exercise and educational level. In pregnant women, the prevalence of HCC was higher than in non-pregnant woman, and was related to educational level. This study emphasises the need to determine the relationship between HCC and confounders such as sociodemographic and lifestyle variables in the general population and specific groups formed by individuals such as pregnant women.This research is part of a doctoral thesis. It has been economically supported by the "PSI2015-63494-P" I+D Project of the Spanish Ministry of Economy and Competitiveness (MINECO) and FEDE