Differences between machine and human testing of shock absorbing systems.

This thesis documents a study on the sources of the differences found between results from machine and walking testing of shock absorbing systems. A complex programme of experiments was conducted at the Institute of Biomechanics of Valencia to explore the four most outstanding statements proposed with this respect: 1. - No accurate simulation of impacts by machine test. This was investigated by comparing results from testing materials simulating impact forces with results from walking tests. 2. - In use materials degrade and their properties change and existing machine testing methods could not replicate material properties during walking. A new testing method was developed to measure the recovery ability of materials by simulating plantar pressures and results compared with walking tests. 3. - Shoe effect on walking kinematics and heel pad confinement has greater influence on shock absorption than material properties. An instrumented pendulum was developed to study the heel pad. Insole materials were evaluated in walking tests, in pendulum tests and in different machine testing including the new method developed simulating plantar pressures and the results compared. 4. - Accommodation to impact conditions occurs according to a controlled proprioceptive feedback model. Accommodation, impact perception, comfort, walking and passive biomechanical variables and material properties were studied in relation to system's input, output and goal. Accurate simulation of impacts improved the ability of machine test to predict the walking performance of materials, but not upper body shock transmission. Properties of materials such as recovery ability, stiffness and hardness play an important role in concepts and passive interaction but mainly by influencing accommodation. Accommodation was identified as the source of differences of results between machine and walking tests of shock absorbing materials. The human body was described as comprising two independent mechanical systems: One system, governed by the elasticity and hardness of materials, it is defined by impact forces and accelerations that are inversely related to upper body transmission and control the perceived impact through foot position and knee bend. The other system is defined by heel pad stiffness, insole properties at initial loading and passive interaction that regulate upper body shock transmission by ankle inversion for comfort control. Passive interaction is defined in this thesis as the mechanical coupling between insole and heel pad that determines the properties of the system either through heel pad confinement or compression. Machine tests appear to predict results with respect to the first system but not the second, which required passive human testing. For insole use, high-energy absorption materials are preferred. These are capable of increasing elastic deformation to reduce impact forces and accelerations without increasing initial-maximal stiffness by passive interaction thus avoiding any increase of head transmission due to accommodation. Heel pad properties were described by three mechanical components accounting for 93.08% of total variance: These are an elastic component, a viscoelastic component and a component related to elastic deformation at low stiffness. Differences were found between shod and barefoot test results. With barefoot there was an initial low stiffness (18-50 kNm*1) response that was not evident in the shod tests which showed elastic deformation related to final stiffness. With barefoot, the elastic component accounted for impact forces variance (> 70%) and initial deformation component for peak force time (> 60%), while shod impact forces were related mainly to the elastic deformation component (> 60%) whereas rate of loading and acceleration were related to the initial-maximal stiffness component (>20%). Differences in heel pad mechanics due to age, gender and obesity were observed. Although the heel pad properties degraded with age, losses appeared to be compensated by obesity

Early Specialty Palliative Care for High Mortality Cancers

Problem: Patients with stage IV cancer have a high mortality rate. Evidence shows that patients have a better quality of life when they receive specialty palliative care (SPC) services. In the microsystem of focus for this project, referrals to SPC are not automatic, and there are no triggers to help the oncologist decide when to refer during a patient’s terminal illness trajectory. Siloes between oncology and SPC exist, which leads to a lack of communication and coordination of care, ultimately affecting patient access to support services from SPC. Context: A multi-disciplinary SPC clinic and a referring oncologist within the same facility partnered to improve early SPC among patients with certain high mortality cancers. Intervention: A weekly oncology/palliative care team huddle was instituted to improve communication and proactively refer, discuss, and plan patient coordination of care. Communication tools were created to enhance patient education and team communication. Measures: Pilot goal was to increase SPC consultation and ongoing follow-up support for stage IV gastrointestinal cancer patients by 20% from a baseline of 37% from February 2021 to 57% by June 31, 2021, for one participating oncologist patient panel. Results: At baseline, 37% (20 out of 54) of patients received SPC consultation and ongoing support. After the huddle interventions, scripted introduction, and direct bookable appointments, 68% (52 out of 76) of patients received SPC consultation and ongoing support. Of the nine patients who died during the project, six died at home with hospice support and three died in the hospital on comfort-only orders. Conclusion: A collaborative and coordinated huddle with oncology resulted in improved consultation and ongoing routine follow up, which benefited the patient and the family by having a peaceful and dignified death concordant with their goals and wishes. The organization benefited by having terminal patients expire with support from hospice or expire without receiving aggressive or ineffective treatment

Fractura femoral en paciente portador de un clavo intramedular

Los autores presentan el caso de un paciente con una fractura femoral tratado con un clavo intramedular cerrojado que sufrió una nueva fractura antes de extraer el material de osteosíntesis.The authors present a patient with a femoral fracture treated by interlocking nail who underwent a new fracture of the femoral shaft before removal of the nail

Association of serum hepcidin with prostate-specific antigen levels in men from high Andean cities of Peru

OBJECTIVE The prostate-specific antigen (PSA) is the primary biomarker to diagnose prostate cancer. Hepcidin has been reported as an alternative for this diagnosis; however, it is unclear how PSA and hepcidin function at high altitude (HA). This study aims to assess the association between hepcidin with PSA in HA residents chronically exposed to hypobaric hypoxia. METHODS We retrospectively examined data of 70 healthy males (aged 18-65-years-old) from four different altitudes cities in Peru: Lima (<150 m), Huancayo (2380 m), Puno (3800 m), and Cerro de Pasco (4320 m). Serum hepcidin, testosterone, and PSA were analyzed by chemiluminescence immunoassay. HA parameters (hemoglobin [Hb], pulse oxygen saturation [SpO$_{2}$], and chronic mountain sickness [CMS] score) were also included in the study. Bivariate analyses and a multivariate linear mixed model were used to evaluate the association between hepcidin and PSA, adjusted by HA parameters, age, and body mass index (BMI). RESULTS Cases of excessive erythrocytosis (EE) (Hb >21 g/dL) were observed in the three highest cities. Hepcidin was positively correlated with Hb, CMS score, and BMI (P ≤ 0.05). Hepcidin was higher in Huancayo with respect to Puno, while PSA was lower in Cerro de Pasco in regard to Puno and Lima (P ≤ 0.05). Neither hepcidin nor PSA was increased by altitude in each city (P > 0.05). We did not find an association between hepcidin and PSA, even adjusted by age, BMI, Hb, and SpO$_{2}$ (P ≤ 0.05). CONCLUSION These findings showed no association between hepcidin and PSA levels in healthy residents at HA

Self-Esteem and the Acute Effect of Anxiety on Ambulatory Blood Pressure

Objectives: Recent research suggests that self-esteem may be associated with improved parasympathetic nervous system functioning. This study tested whether high self-esteem is associated with decreased ambulatory systolic blood pressure (ASBP) reactivity to anxiety in healthy adults during the waking hours of a normal day. Methods: Each of 858 participants completed a short version of the Rosenberg Self-Esteem Scale and then wore an ABP monitor that took two blood pressure readings per hour for 24 hours. Immediately after each blood pressure reading, participants completed an electronic diary report that included an anxiety rating on a 100-point visual analog scale. Using multilevel models, we assessed the association of momentary anxiety, high trait self-esteem, and their interaction on momentary ASBP, with adjustment for age, sex, race, ethnicity, and body mass index. Sensitivity analyses were conducted examining psychological factors associated with self-esteem: sense of mastery, optimism, social support, and depressive symptoms. Results: On average, a 1-point increase in cube root–transformed anxiety was associated with a 0.80-mm Hg (standard error = 0.09, p < .001) increase in ASBP, and the interaction of high self-esteem and momentary anxiety was significant, such that this effect was 0.48 (standard error = 0.20, p = .015) less in individuals with high self-esteem compared with all others. Results for self-esteem remained significant when adjusting for sex and psychological factors. Conclusions: Momentary increases in anxiety are associated with acute increases in ASBP, and high self-esteem buffers the effect of momentary anxiety on blood pressure. Thus, high self-esteem may confer cardiovascular benefit by reducing the acute effects of anxiety on systolic blood pressure

The association of posttraumatic stress disorder and quality of life during the first year after acute coronary syndrome

Acute coronary syndrome [ACS, including unstable angina (UA) or myocardial infarction (MI)] events can be psychologically traumatic experiences for patients given their unpredictable, sudden onset and life-threatening nature [1]. Although posttraumatic stress disorder (PTSD) is commonly associated with index events of war or assault, PTSD is also associated with life-threatening illness and in particular ACS with approximately 12% of patients developing PTSD [1] and [2]. PTSD due to ACS has a multitude of consequences, including increased risk of ACS recurrence and mortality [3] and [4] in addition to PTSD itself being a debilitating psychiatric condition. Sufferers of PTSD are burdened by symptoms that include re-experiencing the traumatic event via intrusive thoughts, flashbacks, or nightmares; avoiding reminders of the index event; persistent negative alterations in cognition and mood; or physiologic hyperarousal. As such, ACS-induced PTSD is likely associated with substantial detriment in quality of life (QOL). However, few studies have measured this association, and no study has investigated it among a general ACS population or longitudinally. Rather, prior studies were composed of ACS patients only in intensive care units (ICUs) or among armed-services veterans [5], [6] and [7] or are notable for limitations such as cross-sectional designs [5] and [7]

Logarithmic Corrections for Spin Glasses, Percolation and Lee-Yang Singularities in Six Dimensions

We study analytically the logarithmic corrections to the critical exponents of the critical behavior of correlation length, susceptibility and specific heat for the temperature and the finite-size scaling behavior, for a generic $\phi^3$ theory at its upper critical dimension (six). We have also computed the leading correction to scaling as a function of the lattice size. We distinguish the obtained formulas to the following special cases: percolation, Lee-Yang (LY) singularities and $m$-component spin glasses. We have compared our results for the Ising spin glass case with numerical simulations finding a very good agreement. Finally, and using the results obtained for the Lee-Yang singularities in six dimensions, we have computed the logarithmic corrections to the singular part of the free energy for lattice animals in eight dimensions.Comment: 18 pages. We have extended the computation to lattice animals in eight dimensions. To be published in Journal of Physics

Construct validation of reading and text production competences in the beginning of the educational reform in the Mexican Elementary School

Este estudio exploratorio fue desarrollado con el propósito de proporcionar evidencias empíricas a la estructuración de competencias lingüísticas por aprendizajes esperados, en el sexto grado de primaria, en los albores de la generalización de la reforma en la primaria mexicana. Para tal fin fue elaborado y sometido a validación de constructo un instrumento de evaluación del español en sexto grado en dos porciones: 1. Competencias de comprensión lectora y 2. Competencias de producción de textos propios, el cual, previa validación por jueces, fue aplicado a 87 alumnos de sexto grado de escuelas públicas del Municipio de Cuautla, Estado de Morelos. Pese a algunas inconsistencias en la especificación de aprendizajes esperados en el Programa de la SEP y de algunas actividades en el libro de texto, los modelos estructurales de análisis confirmatorio respaldaron empíricamente la estructuración de competencias comunicativas y los aprendizajes esperados inherentes a dichas competencias, tanto en comprensión lectora, como en producción de textos.This study was developed with the aim of providing empirical evidence for the structuring of language skills by learning expected in the sixth grade, in the wake of widespread educational reform of the elementary schools in Mexico. For this purpose it was built and subjected to construct validation an assessment instrument in sixth grade in two contests: 1. Reading comprehension and 2. Production of own texts, which, after validation by judges, was administered to 87 sixth grade students of public schools in the municipality of Cuautla, Morelos. In spite of some inconsistencies in the specification of learning expected in the SEP’ program and some activities in the textbook, the structural models with confirmatory analysis, supported the structuring of learning communication competences and the expected learning these skills inherent, in reading comprehension and production of texts

Caracterização de substâncias húmicas extraídas de solo tratado com carvão vegetal (biochar).

As Terras Pretas de Índio (TPI) são solos antropogênicos encontrados na Amazônia, que têm alto teor de carbono (C) orgânico, alta fertilidade e alta capacidade de recuperação. Os TPI possuem estas características devido ao caráter pirogênico do C que neles se encontra, e que se manifestam na alta proporção de estruturas aromáticas policondensadas com grupos funcionais carboxílicos originadas das alterações naturais de biomassa carbonizada adicionada ao solo pelas populações indígenas pré-colombianas

Artroplastia total de tobillo

Presentamos un estudio retrospectivo de siete pacientes tratados con artroplastia total de tobillo en el período 1978-1988, realizando una revisión bibliográfica del tema. La serie la componen cinco hombres y dos mujeres con edades comprendidas entre 41 y 72 años. Cinco pacientes estaban afectos de artrosis postraumática, uno de artropatía gotosa y otro de espondilitis anquilopoyética. Los modelos protésicos utilizados fueron Smith en cuatro ocasiones e I.C.L.H. en tres. El seguimiento medio ha sido de once años, siendo evaluados según un sistema de puntuación creado por Mc Guire. En tres pacientes se ha obtenido un resultado excelente, en dos bueno y los dos restantes fueron reintervenidos realizándose una artrodesis.We have reported a retrospective study of seven patients with total ankle arthroplasty perfomed between 1978-1988. We have reviewed series published in the literature. There were five men and two women, the age range of this group was 41-72 years. Five of them suffered from posttraumatic arthrosis, one ankylosing spondylitis and the last had gouty arthritis. Four patients recieved the Smith total ankle and three the ICLH total ankle. The mean follow-up period was eleven years. Patients were evaluated using a scoring system (Mc Guire et al). Three patients had an excellent result, the result from two of them were good and the other two patients required revision and arthrodesis