Design and optimization methodology for different 3D processed materials (PLA, ABS and carbon fiber reinforced nylon PA12) subjected to static and dynamic loads.

This research presents a methodology for the design and optimization of 3D printed parts with material extrusion (MEX) technology with three different commercial materials: PLA, ABS and N + CF (PA12) subjected to tensile and fatigue stresses, which included three stages: pretreatment, design of experiments and sequential optimization by statistical modeling. In the pretreatment stage, mainly the printing control factors (inner layer and contour height, printing speed, extrusion temperature, nozzle, infill arrangement and printing orientation) were determined; then, factors to optimize tensile strength as a function of printing pattern (linear, 3D, hexagonal), infill percentage (33%, 66%, 100°) and printing orientation (+45°/-45°, 0°/90°) were evaluated. Fatigue analysis was performed as a function of impression orientation using 100% infill, linear impression pattern, 5 Hz and a load range between 90 and 50% UTS. Optimization of tensile strength resulted in parts that exceeded the UTS of their corresponding filament, leading to infinite life relative to fatigue tests. Results were presented for fatigue life prediction based on Weibull analysis, Basquins model and a multivariate response surface correlation analysis. The best fatigue behavior was related to the optimized tensile strength, the infill pattern applied to the printing orientation and the intrinsic properties of ABS (1 × 107cycles, stress up to 20 MPa). With respect to the other materials, a good fatigue behavior was highlighted at the number of cycles achieved 1 × 106 (stress up to 18 MPa) and 1 × 105 (stress up to 24 MPa) for N + CF and PLA, respectively. This study contributes to a better understanding of how printing parameters correlate with tensile and fatigue properties.

Monitorización de la actividad glucolítica secundaria a isquemia en cirugía sustitutiva de rodilla / Monitoring of glycolytic activity secondary to ischaemia in knee replacement surgery

Objetivos: Evaluar de forma no invasiva la lesión tisular secundaria a la isquemia aplicada durante la cirugía sustitutiva de rodilla. Objetivos secundarios: evaluar si dicha lesión se correlaciona con el tiempo que se prolonga la isquemia y la influencia de las variables instrumental y sexo. Material y método: Estudio de cohortes prospectivo. Se han determinado los niveles pre- y postoperatorios de lactato sérico, como indicador de actividad glucolítica secundaria a isquemia, en 88 pacientes. Se han empleado tiras reactivas de detección enzimático-amperométrica sobre sangre capilar. Resultados: Niveles preoperatorios de lactato sérico (media y DE): 2,467±1,036 mmol/L. Niveles postoperatorios de lactato sérico: 3,938±2,018 mmol/L. Tiempo de isquemia 102,98±18,25min. Los niveles postoperatorios de lactato sérico han sido significativamente mayores que los preoperatorios. No existen diferencias atendiendo a las variables tiempo que se prolonga la isquemia, sexo o tipo de instrumentación empleada. Conclusiones: En nuestro estudio, los valores de lactato sérico postoperatorios han sido significativamente mayores que los preoperatorios, sin una correlación con el tiempo que se ha prolongado la isquemia durante la cirugía sustitutiva de rodilla

Objectives: To non-invasively assess tissue lesion secondary to ischaemia applied during knee replacement surgery. Secondary objectives: to assess whether this lesion correlates with the duration of ischaemia and whether instrumental and gender variables influence it. Material and methods: Prospective cohort study. Pre and postoperative serum lactate levels have been determined as an indicator of glycolytic activity secondary to ischaemia in 88 patients. Serum lactate determination was performed by reactive strips of enzymatic-amperometric detection on capillary blood. Results: Preoperative serum lactate levels (mean and SD): 2.467±1.036 mmol/L. Postoperative serum lactate levels: 3.938±2.018 mmol/L. Ischaemia time 102.98±18.25minutes. Postoperative serum lactate levels were significantly higher than preoperative lactate levels. There are no statistical differences according to the time that the ischaemia was prolonged, gender or type of instrumentation used. Conclusions: In our study, postoperative serum lactate values were significantly higher than preoperative lactate values, with no correlation to the duration of ischaemia during knee replacement surgery

Determinación de composición corporal mediante análisis de impedancia segmentada: consideraciones y aplicaciones prácticas / Determination of body composition by segmental bioeletrical impedance analysis: considerations and practical applications

Introduction: Bioelectrical impedance is a fast, inexpensive, easy, portable, and noninvasive method. A major innovation in the analysis of body composition is segmental bioelectrical impedance. Objectives: To assess the applicability of segmental bioelectrical impedance. Subjects and methods: The study was conducted on female subjects divided into two groups: Group I (n =8) consisted of healthy women and group II (n=25) of obese women with Polycystic Ovary Syndrome (PCOS). All subjects were submitted to examination by total and segmental bioelectrical impedance. Results and discussion: Anthropometric parameters (weight, BMI, total lean mass and total fat mass) showed significant differences between groups. There was a significant difference between groups I and II for all body segments evaluated, except for lean mass of the leg. Conclusion: Procedures of segmental bioelectrical impedance will be increasingly useful in the nutritional assessment of tissue masses, enabling assessment that is more sensitive and monitoring of nutritional care.

Introdução : A impedância bioelétrica é um método rápido, barato, fácil, portátil e nao invasivo. Urna grande inovação na análise da composição corporal é a Impedância Bioelétrica Segmentar. Objetivos: Avahar a aplicabilidade da impedância bioelétrica segmentar. Sujetos e Métodos: o estudo foi realizado com individuos do sexo feminino, divididos em: Group I (n=8) composto por mulheres eutróficas e o Group II (n=25) mulheres obesas com Síndrome do Ovario Policístico (SOP). Todos os individuos foram submetidos ao exame de impedância bioelétrica total e segmentar. Resultados e discussão : Os parâmetros antropométricos de peso, IMC, massa magra total e massa gorda total apresentaram diferencas significativas entre os groups. Houve diferenca significativa para todos os segmentos corporais avahados, com exceção da massa magra da perna entre o group I e II. Conclusão : Procedimentos de impedância bioelétrica segmentar serão cada vez mais úteis na avaliação nutricional de massas teciduais, possibilitando avaliações e monitoramentos mais sensíveis do cuidado nutricional.

Metabolic and nutritional interfaces in polycystic ovary syndrome: considerations regarding obesity and dietary macronutrients / Interfaces nutricionales y metabólicas en el síndrome del ovario policístico: el papel de la, obesidad y de los macronutrientes de la dieta

El Síndrome del Ovario Poliquístico (SOP) es un desorden endocrino que ocurre entre las mujeres en edad reproductiva. Se caracteriza por irregularidad menstrual, anovulación crónica, infertilidad e hiperandrogenismo. La prevalencia de la obesidad es alta entre mujeres con el SOP y sus causas aún no están esclarecidas. Anormalidades en el gasto energético y en la respuesta disminuida de las hormonas gastrointestinales responsables por el control de la ingestión alimentaria, especialmente la grelina son posibles hipótesis para explicar la obesidad asociada al SOP. Los efectos de la composición dietética en el SOP aún están poco explorados. Es posible que los ácidos grasos poliinsaturados (PUFA) mejoran la sensibilidad insulínica y que dietas hiperproteicas potencializan la pérdida de peso y mejoran la función reproductiva. Sin embargo, las evidencias actuales no son suficientes para determinar las características dietéticas mas adecuadas para el SOP. La conducta dietética debe enfocar la pérdida de peso con dietas nutricionalmente completas y balanceadas.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women at reproductive age. Its classical form is characterized by menstrual irregularities, chronic anovulation, infertility, and hyperandrogenism. The prevalence of obesity is high among women with POS and its causes have not been fully clarified. Hypotheses have been raised suggesting the possible presence of both abnormal energy expenditure and a reduced response of the gastrointestinal hormones responsible for the control of food ingestion, especially ghrelin. The specific effects of diet composition on POS have been little explored. It has been suggested that po-lyunsaturated fatty acids may improve insulin sensitivity and that high-protein diets may potentiate weight loss and improve reproductive function. However, current evidence is insufficient to determine the optimum composition of a diet for POS patients. The dietary conduct should focus on weight loss to be achieved with nutritionally complete and balanced diets.

[Postoperative patient-controlled analgesia is more effective with epidural methadone than with intravenous methadone in thoracic surgery]. / La analgesia postoperatoria controlada por el paciente es más efectiva con metadona epidural que con metadona endovenosa en la cirugía torácica.

OBJECTIVE: To compare the efficacy and side effects of epidural and intravenous methadone for postoperative patient-controlled analgesia (PCA) after thoracic surgery. PATIENTS AND METHODS: A randomized, single-blind trial enrolling 30 patients distributed in 2 groups to receive intravenous methadone (ivPCA group) or epidural methadone (epPCA group). Patients in both groups were administered a loading dose of 0.05 mg.kg-1 followed by infusion of 0.5 mg.h-1. The patients could self-dose 0.5 mg with a lock-out interval of 10 minutes and a maximum of 4 doses per hour. Patient characteristics, type and duration of surgery and fentanyl dose were recorded. Pain was assessed on a visual analog scale (VAS). Level of sedation, respiratory rate and occurrence of nausea, vomiting and pruritus were also recorded over the first 24 hours. RESULTS: The 2 groups were comparable. Pain was greater in the ivPCA group than in the epPCA group in the second hour (VAS 3.93 +/- 1.9 and 2.4 +/- 1.65, respectively; P < .05) and the third hour (VAS 3.57 +/- 1.65 and 1.5 +/- 1.16, respectively; P < .05). The total dose of methadone administered was 25.34 +/- 5.65 mg in the ivPCA group and 18.82 +/- 3.52 mg in the epPCA group (P < .002). There were no significant differences in side effects. CONCLUSIONS: The results suggest that epidural methadone has an intrinsic spinal effect regardless of whether or not there is extra-spinal action arising from syste mic absorption. Epidural methadone provides a more adequate analgesic effect in less time and at a lower dose. Both approaches provide good postoperative analgesia with few side effects.

La analgesia postoperatoria controlada por el paciente es más efectiva con metadona epidural que con metadona endovenosa en la cirugía torácica / Epidural methadone is more effective than intravenous methadone in postoperative patient-controlled analgesia after thoracic surgery

OBJETIVO: Comparar la efectividad y efectos secundarios de la metadona administrada por vía epidural y endovenosa en la analgesia postoperatoria controlada por el paciente (PCA) en toracotomías. PACIENTES Y MÉTODOS: Estudio prospectivo y simple ciego en 30 pacientes divididos aleatoriamente en dos grupos según la vía de administración de la metadona: grupo PCAEV endovenosa y grupo PCAEP epidural. En ambos grupos se administraba un bolo inicial de 0,05 mg-Kg-1 seguido de una infusión de 0,5 mg-h-1. Los pacientes se podían autoadministrar bolos de 0,5 mg, con intervalo de cierre de 10 minutos y un máximo de 4 bolos a la hora. Se recogieron variables demográficas, tipo y duración de la cirugía y dosis de fentanilo. Se registró el dolor según la escala visual analógica (EVA), el grado de sedación, la frecuencia respiratoria y la incidencia de náuseas, vómitos y prurito en las primeras 24 horas. RESULTADOS: Ambos grupos resultaron homogéneos. El dolor fue superior en el grupo PCAEV sobre el PCAEP en la segunda hora (EVA 3,93 ñ 1,9 y 2,42 ñ 1,65; p<0,05) y en la tercera hora (EVA 3,57 ñ 1,65 y 1,5 ñ 1,16; p<0,05); posteriormente el valor de EVA fue inferior a 3 en ambos grupos. La dosis total de metadona administrada en el grupo PCAEV fue 25,34 ñ 5,65 mg y 18,82 ñ 3,52 mg en el PCAEP (p<0,002). No hubo diferencias significativas en los efectos secundarios. CONCLUSIONES: Los resultados sugieren que la metadona epidural posee un efecto espinal intrínseco, independientemente de que se añada una acción indirecta supraespinal por absorción sistémica. La metadona epidural produce un nivel analgésico más adecuado en menos tiempo y con menos dosis. Ambas vías proporcionan una buena analgesia postoperatoria con pocos efectos secundarios (AU)

[Morbidity and mortality related to anesthesia and surgery in 60 patients treated with bariatric surgery]. / Morbimortalidad anestésica-quirúrgica en 60 pacientes intervenidos de cirugía bariátrica.

OBJECTIVE: To identify the factors predicting morbidity and mortality in patients undergoing bariatric surgery for morbid obesity in our hospital. METHOD: Sixty bariatric surgery patients whose body mass indexes (BMI) exceeded 35 kg.m-2 were studied retrospectively. We examined the incidence of associated disease, the perioperative period, type of surgery, anesthetic technique, postoperative analgesia and the incidence of major complications. RESULTS: Fifty-one women and 9 men (mean age 43.33 +/- 10.25 years, mean BMI 46.41 +/- 6.04 kg/m-2) were studied. The incidences of high blood pressure (55%) and obstructive sleep apnea syndrome (40%) were high. Nine patients (15%) were physical status (ASA) I, 18 (30%) were ASA II, 27 (45%) were ASA III and 6 (10%) were ASA IV. Major complications developed in 3 cases (5%) in the first 24 h and in 8 (13.33%) in the first 7 days. The mortality rate was 0% among ASA I and II patients, 3.7% (1 death) among ASA III patients, and 33.33% (2 deaths) among ASA IV patients. All who died were men. The only factor that predicted morbidity in the first week after surgery was BMI. Both morbidity in the first 24 h and mortality were associated with greater underlying disease in our patients undergoing bariatric surgery. CONCLUSION: Major complications of bariatric surgery occurred in 18.3% of our patients and mortality was 5%. Physical status was a prognostic factor for both early (24 h) postoperative morbidity and mortality in our morbidly obese patients, whereas BMI was related to morbidity during the first week after surgery.