Volt-ampere characteristics of cylindrical and spherical Langmuir probes for various potential models Scientific report

Volt-ampere characteristics of cylindrical and spherical Langmuir probes for various potential model

MEASUREMENT OF PLANTAR PRESSURE DURING HIGH IMPACT-SHORT CONTACT TIME SPORTS ACTIVITIES

INTRODUCTION Force Measurement is an important part of biomechanical research. Until now the measurement of plantar force during the more dynamic sports events have been primarily limited to the laboratory because the available systems capable of accurately measuring 'high impact-short contact-time' forces are not very portable. The purpose of this study was to evaluate the use of soft Parotec pressure sensors inside the shoe as a means of portable and reliable force measurement during jumping sport movements. METHODS The subjects (n =14) performed a series of 'depth jump' exercises simulated by a falling pendulum. Force curves were generated with the use of 4 soft Parotec force sensors (data collection rate 1000 Hz) which were held to the underside of the right fore-foot (Hallux, Metatarsals 1, 3, and 5) using tape and gymnastic shoes. Force curves were simultaneously generated using Kistler force sensors (data collection rate 1000Hz) which were used as control in evaluating the accuracy of the Parotec sensors. The following temporal aspects of the force curves were compared: total contact time (CT), time to first peak (TI), and time to second peak (T2). Further parameters were force at first peak(Fl), force at the saddle (FS) between the first and second peaks, and maximum force (F2). The times between initial contact and T1 and T2 were consistently (approx 70%) identical (+I- Oms) for both systems, although a variance of lms in either direction was seen in approximately 30% of the trials for both values. Although the time of initial contact was consistantly recorded the same by both systems the comparison of the exact total contact time was not usually possible because indistinct 'take-off' times were often measured by Parotec due to residual pressure in the shoe. As expected the force measured by the Parotec sensors recorded considerably less of the total force than the Kistler system. The Parotec sensors recorded force most accurately for the FS and F1 values where they captured up to 48% and 47% respectively of the force measured by the Kistler sensors. For the F2 force values they captured up to 32% of the force measured by Kistler. Greater discrepancies in force values were seen at higher total force values. CONCLUSIONS The comparison of the force curves in this study indicate that Parotec sensors, as used in the above described configuration for high impact-short contact time movements, are accurate in measuring important force parameters. This accuracy was best for the various time measurements. More experimentation is required in the of number of sensors and sensor placement to better measure the force for these type of movements

Initial experience with magnetic resonance imaging-safe pacemakers: A review

Due of its superior soft tissue imaging capabilities, magnetic resonance imaging (MRI) has become the imaging modality of choice in many clinical situations, as illustrated by the tremendous growth in the number of MRIs performed over the past 2 decades. In parallel, the number of patients who require pacemakers or implantable cardiac defibrillators is increasing as indications for these devices broaden and the population ages. Taken together, these phenomena present an important clinical issue, as MR scans are generally contraindicated—except in urgent situations—in patients who have implanted cardiovascular devices. Potentially deleterious interactions between the magnetic fields and radio frequency (RF) energy produced by MR equipment and implantable devices have been identified, including inhibition of pacing, asynchronous/high-rate pacing, lead tip heating, and loss of capture. New devices that incorporate technologies to improve MR safety in patients with pacemakers have recently received approval in Europe and are under evaluation in the United States. Initial data from these devices suggest that these devices are safe in the MRI environment

Imaging of the urinary tract: the role of CT and MRI

Computed tomography (CT) and magnetic resonance imaging (MRI) are increasingly valuable tools for assessing the urinary tract in adults and children. However, their imaging capabilities, while overlapping in some respects, should be considered as complementary, as each technique offers specific advantages and disadvantages both in actual inherent qualities of the technique and in specific patients and with a specific diagnostic question. The use of CT and MRI should therefore be tailored to the patient and the clinical question. For the scope of this article, the advantages and disadvantages of these techniques in children will be considered; different considerations will apply in adult practice

Copper complexes for the promotion of iminopyridine ligands derived from β-alanine and self-aldol additions: relaxivity and cytotoxic properties

Producción CientíficaIn the study presented herein, we explore the ability of copper complexes with coordinated pyridine-2-carboxaldehyde (pyca) or 2-acetylpyridine (acepy) ligands to promote the addition of amines (Schiff condensation) and other nucleophiles such as alcohols (hemiacetal formation). Distinct reactivity patterns are observed: unlike pyca complexes, acepy copper complexes can promote self-aldol addition. The introduction of a flexible chain via Schiff condensation with β-alanine allows the possibility of chelate ring ring-opening processes mediated by pH. Further derivatization of the complex [CuCl(py-2-C(H)[double bond, length as m-dash]NCH2CH2COO)] is possible by replacing its chloride ligand with different pseudohalogens (N3−, NCO− and NCS−). In addition to the change in their magnetism, which correlates with their solid-state structures, more unexpected effects in their cytotoxicity and relaxitivities are observed, which determines their possibility to be used as MRI contrast agents. The replacement of a chloride by another pseudohalogen, although a simple strategy, can be used to critically change the cytotoxicity of the Schiff base copper (II) complex and its selectivity towards specific cell lines.Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación - FEDER (projects PGC2018-096880-A-I00 / PGC2018-099470-B-I00)Ministerio de Economía, Industria y Competitividad - Agencia Estatal de Investigación - FEDER - UE (contract RYC-2015-19035)Junta de Castilla y León (project VA130G18)Laboratory of Excellence of Nanostructures in Interaction with their Environment (project ANR-11-LABX-0058-NIE within the Investissement d'Avenir program ANR-10-IDEX-0002-02)