Conducting Action Research to Improve Operational Efficiency in Manufacturing: The Case of a First-Tier Automotive Supplier.

Optimising available resources and minimising production costs and throughput time is vital for first-tier suppliers in the worldwide automotive sector. To develop this type of optimisation and efficiency, MAHLE applied Action Research (AR) in one of its factories located in Spain. A multidisciplinary collaborative work team was created with the aim of deploying the AR initiative in combination with Lean Manufacturing and Six Sigma tools. Four improvement and learning cycles were deployed and key performance metrics were defined to collect and measure data in order to analyse the improvements achieved. The application of the AR initiative in the production line of a power filter device enabled improvements in both production times and quality indicators in the manufacturing process. The most outstanding results were the improvements made in the decrease in initial throughput time (34.78%) and in average daily rejections (73.53%). In addition, the AR initiative generated practical and theoretical contributions for business and academia, allowing the AR initiative to be applied in other areas of the company, and contributing to the current state of the art in the industrial application of this methodology.

The adoption of internet of things in a circular supply chain framework for the recovery of WEEE: the case of lithium-ion electric vehicle battery packs.

The rapid growth in the sales of electric and electronic devices over recent decades is generating worldwide concern about the management of Waste Electrical and Electronic Equipment (WEEE). New methodologies to extend the useful life of products have long been sought, accelerating the shift from a linear to a Circular Economy (CE). When products reach the End-of-Life (EoL) stage, the Reverse Supply Chain (RSC) is responsible for managing operations, with greater efforts being needed to improve the associated information infrastructure. In fact, this has become increasingly feasible due to the emergence of a new digital revolution led by the Internet of Things (IoT). To shed light on this matter, we propose the Circular Supply Chain (CSC) framework for EoL management aimed at satisfying the information infrastructure requirements in a particular scenario for the recovery of Electric Vehicle Battery (EVB) packs. We present a qualitative evaluation of the CSC information requirements, and the capabilities of IoT to satisfy them. As a result, a heterogeneous IoT network deployment is proposed in pursuit of a digital CSC information infrastructure.

Effect of spermine conjugation on the interaction of acridine with alternating purine-pyrimidine oligodeoxyribonucleotides studied by CD, fluorescence and absorption spectroscopies.

We studied by electronic spectroscopies the interaction between double-stranded oligonucleotides containing either adenine-thymine or guanine-cytosine alternating sequences and N(1)-(acridin-9-yl)-1,16-diamino-4,8,13-triazahexadecane, which is a conjugated molecule formed by the covalent binding of spermine and 9-aminoacridine moieties via a trimethylene chain. Solutions containing the oligonucleotides and the conjugate, at different molar ratios, were studied by using electronic absorption, fluorescence emission and circular dichroism. Calculated association constants and fluorescence emission spectra showed that spermine conjugation induces sequence selectivity. The orientation of the intercalated acridine rings with respect to the oligonucleotide base planes was deduced from the electronic circular dichroism spectra. Evidence of the formation of spermine-induced aggregated structures, with potential applications to DNA packaging, gene therapy and anti-tumor therapy, was also achieved. Our data demonstrates that this spermine-acridine conjugate adds several specific characteristics provided by the polyamine moiety, as sequence selectivity, to the interesting properties of acridine derivatives.

Structural and vibrational study of the tautomerism of histamine free-base in solution.

Infrared and Raman spectroscopy in H(2)O and D(2)O and quantum Density Functional calculations were used to determine the structure of histamine free-base in aqueous solution. A quantum mechanical study of the tautomeric equilibrium of histamine free-base in solution was performed at the 6-311G level. Electronic correlation energies were included by using the hybrid functional B3LYP. The solvent was simulated as a continuum characterized by a dielectric constant, and the quantum system (solute) was placed in an ellipsoidal cavity. Solute-solvent electrostatic interaction was calculated by means a multipolar moment expansion introduced in the Hamiltonian. Four relevant histamine conformations were optimized by allowing all the geometrical parameters to vary independently, which involved both the gauche-trans and the N3H-N1H tautomerisms. The calculated free energies predicted N3H-gauche as the most stable one of histamine free-base in solution. The order of stability is here completely altered with respect to previous results in gas phase, which presented the N1H-gauche conformer as the most stable structure. Our results also differ from previous Monte Carlo simulations, which obtained the N3H-trans conformer as the most stable in solution, although in this case, the histamine structures were kept frozen to the gas-phase geometry. Vibrational spectroscopy results support theoretical ones. Quadratic force fields for the four histamine conformers were achieved under the same calculation methodology. Previously, a general assignment of the infrared and Raman spectra of histamine free-base was proposed for solutions in both natural and heavy water. This allowed us to compare the experimental set of both wavenumbers and infrared intensities with the calculated ones. The lowest quadratic mean wavenumber deviation was obtained for the N3H-gauche conformer, in agreement with the free-energy calculations. Calculated infrared intensities were also compared to the experimental intensities, supporting this conformer as the relevant structure of histamine free-base in solution. It was then selected for a complete vibrational dynamics calculation, starting with a low-level scaling procedure to fit the set of calculated wavenumbers to the experimental values. The results were presented in terms of quadratic force constants, potential energy distribution, and normal modes.

Utilidad del eco trans-esofágico en el estudio de la disección aórtica / Usefulness of transesophageal echocardiography in patients with aortic dissection

La disección aórtica (DA) debe ser diagnosticada y tratada precozmente para reducir mortalidad. Mientras que la DA de aorta ascendente requiere cirugía de emergencia, la de aorta descendente es frecuentemente de tratamiento médico. Con el fin de analizar la utilidad del eco trans esofágico (ETE) en el diagnóstico y clasificación de la DA, de 172 ETE consecutivos, se estudió a 12 pacientes en los que el examen se efectuó de urgencia por sospecha clínica de DA. El diagnóstico fue comprobado en 8 de ellos en base al ETE y procedimientos adicionales que incluyeron TAC de tórax, angiografía, cirugía y/o necropsia. De los 4 no confirmados por eco todos tenían TAC y uno angiografía. Comparando con angriografía y TAC la sensibilidad y especificidad del ETE fue de 100%. De los 8 pacientes con DA, 7 eran tipo 3 y uno tipo 1. Se destaca la utilidad del ETE para demostrar etiología (Marfán en 3), existencia de reflujo aórtico (presente en 2 y en 4 de ellos no debido a la DA), sitio de ruptura (5 casos), lumen y falso lumen (todos), presencia de flap (todos), existencia de trombos (3 casos). Tanto en la delimitación de extensión, como en el análisis de los segmentos de aorta ciegos al ETE y en la precisión del compromiso de ramas vasculares, la complementación con el Transtorácido fue necesaria. La ejecución del examen fue expedita y sin complicaciones. Se confirma que el ETE es una técnica útil y segura para el estudio de urgencia de la DA. Permite definir etiología, confirmar diagnóstico, determinar ubicación y extensión de la DA y demostrar complicaciones

Estudio hemodinámico no invasivo de grandes y pequeñas arterias: técnicas y valores normales / Non invasive hemodynamic study of large an small arteries: technique and normal values

En la hipertensión arterial, el estudio hemodinámico invasivo ha estado enfocado a estimar la resistencia periférica total (pr/flujo) y con ella, la reactividad de las arteriolas (que manejan el 70% de la R. total). No se estudiaban los cambios de calibre de las grandes arterias porque se las consideraba sólo como vasos de capacitancia. Sin embargo, éstas también experimentan cambios de tonus (y manejan el resto de la R. total). Además, la RP total constituye la resultante de la R. de diversos territorios con R. muy elevadas (esplánico, renal) ó bajas (muscular). La introducción de la técnica Duplex ECO-Doppler pulsados con transductor de 7,5 MHZ por Safar y col. aplicada a grandes arterias superficiales (corótida, humeral) permite estudiar la hemodinámia de grandes arterias, midiendo suu calibre (ECO) y también de las arteriolas , midiendo la Vel. de flujo (Doppler pulsado) pues a mayor R. arteriolar, menor Vel. de flujo (VF) y viceversa. Determinando simultáneamente a PA con el manguito, se puede calcular el flujo sanguíneo local (IID2/4 x VF), R. periférica local (pr media/vol sanguíneo sistólico/pr de pulso). Para estudiar los valores normales y la reproducibilidad de la técnica, se aplicó ésta a 26 sujetos normales, repitiendo 1 vez en días diferentes. Los resultados promedios de ambas mediciones, evaluadas por el test de "t" pareado no difirieron más del 5% y tampoco lo hicieron las 3 mediciones hechas en cada examen para el diámetro (<5%) y la velocidad media de flujo (<8%). Se concluye que la técnica ECO-Doppler aplicada a la arteria humeral es simple, reproducible con error 10% y da información útil separadamente de la reactividad de grandes arterias y arteriolas y de la compliance arterial, lo que constituye un valioso modelo experimental para estudiar el efecto hemodinámico de drogas en el sujeto normal y en el hipertenso