High throughput automated characterization of enamel microstructure using synchrotron tomography and optical flow imaging.

The remarkable damage-tolerance of enamel has been attributed to its hierarchical microstructure and the organized bands of decussated rods. A thorough characterization of the microscale rod evolution within the enamel is needed to elucidate this complex structure. While prior efforts in this area have made use of single particle tracking to track a single rod evolution to various degrees of success, such a process can be both computationally and labor intensive, limited to the evolution path of a single rod, and is therefore prone to error from potentially tracking outliers. Particle image velocimetry (PIV) is a well-established algorithm to derive field information from image sequences for processes that are time-dependent, such as fluid flows and structural deformation. In this work, we demonstrate the use of PIV in extracting the full-field microstructural distribution of rods within the enamel. Enamel samples from a wild African lion were analyzed using high-energy synchrotron X-ray micro-tomography. Results from the PIV analysis provide sufficient full-field information to reconstruct the growth of individual rods that can potentially enable rapid analysis of complex microstructures from high resolution synchrotron datasets. Such information can serve as a template for designing damage-tolerant bioinspired structures for advanced manufacturing. STATEMENT OF SIGNIFICANCE: Thorough characterization and analysis of biological microstructures (viz. dental enamel) allows us to understand the basis of their excellent mechanical properties. Prior efforts have successfully replicated these microstructures via single particle tracking, but the process is computationally and labor intensive. In this work, optical flow imaging algorithms were used to extract full-field microstructural distribution of enamel rods from synchrotron X-ray computed tomography datasets, and a field method was used to reconstruct the growth of individual rods. Such high throughput information allows for the rapid production/prototyping and advanced manufacturing of damage-tolerant bioinspired structures for specific engineering applications. Furthermore, the algorithms used herein are freely available and open source to broaden the availability of the proposed workflow to the general scientific community.

Characterizing the microstructures of mammalian enamel by synchrotron phase contrast microCT.

The enamel of mammalian teeth is a highly mineralized tissue that must endure a lifetime of cyclic contact and is inspiring the development of next-generation engineering materials. Attempts to implement enamel-inspired structures in synthetic materials have had limited success, largely due to the absence of a detailed understanding of its microstructure. The present work used synchrotron phase-contrast microCT imaging to evaluate the three-dimensional microstructure of enamel from four mammals including Lion, Gray Wolf, Snow Leopard, and Black Bear. Quantitative results of image analysis revealed that the decussation pattern of enamel consists of discrete diazone (D) and parazone (P) bands of rods organized with stacking arrangement of D+/P/D-/P in all mammals evaluated; the D+ and D- refer to distinct diazone bands with juxtaposed rod orientations from the reference plane. Furthermore, the rod orientations in the bands can be described in terms of two principal angles, defined here as the pitch and yaw. While the pitch angle increases from the outer enamel to a maximum (up to ≈ 40°) near the dentin enamel junction, minimal spatial variations are observed in yaw across the enamel thickness. There are clear differences in the decussation parameters of enamel across species that are interpreted here with respect to the structural demands placed on their teeth. The rod pitch and band width of enamel are identified as important design parameters and appear to be correlated with the bite force quotient of the four mammals evaluated. STATEMENT OF SIGNIFICANCE: The multi-functionality of tooth enamel requires both hardness and resistance to fracture, properties that are generally mutually exclusive. Ubiquitous to all mammalian teeth, the enamel is expected to have undergone adaptations in microstructure to accommodate the differences in diet, body size and bite force across animals. For the first time, we compare the complex three-dimensional microstructure of enamel from teeth of multiple mammalian species using synchrotron micro-computed tomography. The findings provide new understanding of the "design" of mammalian enamel microstructures, as well as how specific parameters associated with the decussation of rods appear to be engineered to modulate its fracture resistance.

Estrategias orientadas a mejorar la adherencia a la rehabilitación y la actividad física tras cirugía de artroplastia total de rodilla: revisión sistemática con metaanálisis / Strategies aimed at improving adherence to rehabilitation and physical activity after total knee arthroplasty surgery: Systematic review with meta-analysis

Introducción y objetivo Los sujetos intervenidos por artroplastia total de rodilla (ATR) muestran bajos niveles de adherencia a la rehabilitación y al ejercicio físico. El objetivo de este estudio es recopilar y revisar los efectos de las estrategias orientadas a mejorar la adherencia al ejercicio físico en la rehabilitación tras ATR. Métodos Se llevó a cabo una revisión sistemática de la literatura (Cochrane, PEDro, MedLine), incluyendo aquellos estudios que emplearan estrategias encaminadas a mejorar la adherencia a la rehabilitación tras ATR. Se analizaron los efectos de las intervenciones en términos de dolor y funcionalidad (variables primarias), así como en las variables relacionadas con la adherencia, realizando un metaanálisis a partir de las diferencias de medias estandarizadas (DME; IC95%) entre las puntuaciones de la intervención experimental y control. Resultados Se recogieron nueve estudios que incluían estrategias encaminadas a mejorar la adherencia a la rehabilitación tras ATR. El metaanálisis reveló un ligero efecto a favor del grupo experimental en términos de dolor (DME; IC95%: 0,31 [0,09-0,54], p<0,01), pero no en cuanto a la funcionalidad. Cualitativamente, los resultados relacionados con la adherencia fueron heterogéneos o inconsistentes. Conclusiones Los efectos de las estrategias empleadas para mejorar la adherencia al ejercicio físico en la rehabilitación tras ATR son heterogéneos e inconcluyentes, aunque se sugieren ligeros efectos positivos en cuanto al dolor. La diversidad de resultados en los estudios individuales y la heterogeneidad en el diseño de las intervenciones implican la necesidad de futuras investigaciones (AU)

Introduction and objectives Subjects undergoing by total knee arthroplasty (TKA) show low levels of adherence to rehabilitation and physical exercise. The aim of this study is to collect and review the effects of strategies aimed at improving adherence to physical exercise in rehabilitation after TKA. Methods A systematic review of the literature (Cochrane, PEDro, and MedLine) was carried out, including those studies that employed strategies aimed at improving adherence to rehabilitation after TKA. We analyzed the effects of the interventions in terms of pain and functionality (primary variables), as well as adherence-related variables, performing a meta-analysis based on the standardized mean differences (SMD; 95%CI) between experimental and control intervention scores. Results Nine studies were collected that included strategies aimed at improving adherence to rehabilitation after TKA. Meta-analysis revealed a slight effect in favor of the experimental group in terms of pain (SMD; 95%CI: 0.31 [0.09-0.54], P<.01]), but not in terms of functionality. Qualitatively, results related to adherence were heterogeneous or inconsistent. Conclusion The effects of strategies employed to improve adherence to physical exercise in rehabilitation after TKA are heterogeneous and inconclusive, although slight positive effects on pain are suggested. The diversity of results in the individual studies and the heterogeneity in the design of the interventions imply the need for future research (AU)

Participación latinoamericana en la producción científica de SEMERGEN / Latin American participation in the scientific production of SEMERGEN

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Efectos de un programa de ejercicio combinado de impacto, fuerza y resistencia en la prevención de osteoporosis de mujeres posmenopáusicas / Effects of a combined impact, strength and endurance exercise program in the prevention of osteoporosis in post-menopausal women

Antecedentes y objetivo: Las mujeres posmenopáusicas son una población susceptible de desarrollar osteoporosis. El objetivo del presente estudio fue determinar los efectos de un programa de ejercicio físico combinado de impacto, fuerza y resistencia en mujeres posmenopáusicas. Materiales y métodos: Estudio de intervención prospectivo, con un grupo que incluyó a mujeres posmenopáusicas que no tenían pautado tratamiento farmacológico para la prevención de osteoporosis. Se realizó una intervención de 2 años de duración, con 2 sesiones de entrenamiento por semana, basada en ejercicios de impacto, fuerza y resistencia progresiva. Se estimó el índice T score en fémur y columna para determinar posibles cambios en la densidad mineral ósea tras la intervención. Resultados: Dieciséis mujeres de 49,4 años (DE 5,2) formaron parte del estudio. Tras la intervención, no se encontraron diferencias significativas con respecto a los valores basales de T score de fémur y columna (p > 0,05), lo que indica que los niveles de densidad ósea se mantuvieron tras 2 años. Conclusiones: Dos años de entrenamiento para prevención de osteoporosis basado en un programa combinado de resistencia, fuerza e impacto es efectivo para mantener los niveles de densidad mineral ósea de mujeres posmenopáusicas. Los resultados indican que el ejercicio físico sin tratamiento farmacológico es efectivo para la prevención de osteoporosis en esta población

Background and objective: Post-menopausal women are a population susceptible to osteoporosis. The objective of this study was to determine the effects of a combined physical exercise program including impact, strength and progressive resistance exercises in post-menopausal women. Materials and methods: Prospective quasi-experimental study, with an intervention group that included post-menopausal women with no prescribed pharmacological treatment for the prevention of osteoporosis. A 2-year intervention program was implemented, with 2 training sessions per week, based on impact, strength and progressive resistance exercises. The T-score index in the femur and lumbar spine was estimated in order to determine possible changes in bone mineral density after the intervention. Results: A total of 16 women, with a mean age of 49.4 (SD: 5.2) participated. After the intervention, no significant differences were found with respect to baseline T-score of femur and spine (P>.05), suggesting that bone density levels were maintained after 2 years. Conclusions: Two years of osteoporosis prevention training based on a combined resistance, strength and impact program is effective in maintaining bone mineral density levels in post-menopausal women. The results suggest that physical exercise without pharmacological treatment is effective for the prevention of osteoporosis in this population

Food allergy in breastfeeding babies. Hidden allergens in human milk.

BACKGORUND: Food allergy is a rare disorder among breastfeeding babies. OBJECTIVE: Our aim was to identify responsible allergens in human milk. METHODS: We studied babies developing allergic symptoms at the time they were breastfeeding. Skin prick tests (SPT) were performed with breast milk and food allergens. Specific IgE was assessed and IgE Immunoblotting experiments with breast milk were carried out to identify food allergens. Clinical evolution was evaluated after a maternal free diet. RESULTS: Five babies had confirmed breast milk allergy. Peanut, white egg and/or cow's milk were demonstrated as the hidden responsible allergens. No baby returned to develop symptoms once mother started a free diet. Three of these babies showed tolerance to other food allergens identified in human milk. CONCLUSION: A maternal free diet should be recommended only if food allergy is confirmed in breastfed babies.

Aspirin desensitization achieved after Omalizumab treatment in a patient with Aspirin-exacerbated urticaria and respiratory disease

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A novel antigen-carrier system: the Mycobacterium tuberculosis Acr protein carried by raw starch microparticles.

Microparticles have been used as promising carriers for in vivo vaccine delivery. However, the processes for immobilizing peptides or proteins on microparticles usually require the use of undesirable compounds and complex protocols. In this work, we propose a new immobilization and delivery system with raw starch microparticles and a starch binding domain (SBD) tag fusion protein. The heat shock protein alpha crystallin from Mycobacterium tuberculosis was used as model. The immunogenicity of the system was investigated in BALB/c mice inoculated with purified Acr-SBDtag protein (pAcr-SBDtag) and starch immobilized Acr-SBDtag protein (µAcr-SBDtag) by oral and intranasal routes. We demonstrated mucosal immunization with the µAcr-SBDtag protein induced systemic antibodies that were predominantly immunoglobulin G2a (IgG2a). An analysis of the cytokines from spleen cells and lung homogenates revealed that loaded microparticles induced the secretion of interferon-γ (INF-γ), suggesting an adjuvant effect from the immobilization. The immune responses induced by immobilized protein were primarily affected by the route of administration. These results demonstrate that the system exhibits the necessary characteristics to improve antigen release and presentation to antigen presenting cells (APCs) in the mucosae. Because no extra adjuvants were used, we posit that the system may be suitable for delivery and presentation to the field of subunit vaccine development.

Dynamics of suspended sediment borne persistent organic pollutants in a large regulated Mediterranean river (Ebro, NE Spain).

Mediterranean rivers are characterized by highly variable hydrological regimes that are strongly dependent on the seasonal rainfall. Sediment transport is closely related to the occurrence of flash-floods capable to deliver enough kinetic energy to mobilize the bed and channel sediments. Contaminants accumulated in the sediments are likely to be mobilized as well during such events. However, whereas there are many studies characterizing contaminants in steady sediments, those devoted to the transport dynamics of suspended-sediment borne pollution are lacking. Here we examined the occurrence and transport of persistent organic microcontaminants present in the circulating suspended sediments during a controlled flushing flow in the low part of the River Ebro (NE Spain) 12 km downstream of a well-known contaminated hot-spot associated to a nearby chloro-alkali industry. Polycyclic aromatic hydrocarbons (PAHs) and semi-volatile organochlorine pollutants (DDT and related compounds, DDX; polychlorinated byphenils, PCBs; and other organochlorine compound, OCs) were measured in the particulate material by GC-MS and GC-MS/MS, using previously developed analytical methods. The concentration levels observed were compared to previously reported values in steady sediments in the same river and discussed on a regulatory perspective. Hydrographs and sedigraphs recorded showed a peak-flow of 1,300 m(3)s(-1) and a corresponding peak of suspended sediments of 315 mg L(-1). Combination of flow discharge, suspended sediments and pollutants' concentrations data allowed for quantifying the mass flows (mass per unit of time) and setting the load budgets (weight amount) of the different pollutants transported by the river during the monitored event. Mean mass-flows and total load values found were 20.2 mg s(-1) (400 g) for PAHs, 38 mg s(-1) (940 g) for DDX, 44 mg s(-1) (1,038 g) for PCBs and 8 mg s(-1) (200 g) for OCs. The dynamic pattern behavior of PAHs differs substantially to that of organochlorine pollutants, thus reflecting different pollution origins.

The starch-binding domain as a tool for recombinant protein purification.

Recombinant protein purification with affinity tags is a widely employed technique. One of the most common tags used for protein purification is the histidine tag (Histag). In this work, we use a tandem starch-binding domain (SBDtag) as a tag for protein purification. Four proteins from different sources were fused to the SBDtag, and the resulting fusion proteins were purified by affinity chromatography using the Histag or the SBDtag. The results showed that the SBDtag is superior to the Histag for protein purification. The efficient adsorption of the fusion proteins to raw corn starch was also demonstrated, and two fusions were selected to test purification directly using raw starch from rice, corn, potato, and barley. The two fusion proteins were successfully recovered from crude bacterial extract using raw starch, thus demonstrating that the SBDtag can be used as an efficient affinity tag for recombinant protein purification on an inexpensive matrix.

Prioritization of chemicals in the aquatic environment based on risk assessment: analytical, modeling and regulatory perspective.

The extensive and intensive use of chemicals in our developed, highly technological society includes more than 100,000 chemical substances. Significant scientific evidence has lead to the recognition that their improper use and release may result in undesirable and harmful side-effects on both the human and ecosystem health. To cope with them, appropriate risk assessment processes and related prioritization schemes have been developed in order to provide the necessary scientific support for regulatory procedures. In the present paper, two of the elements that constitute the core of risk assessment, namely occurrence and hazard effects, have been discussed. Recent advances in analytical chemistry (sample pre-treatment and instrumental equipment, etc.) have allowed for more comprehensive monitoring of environmental pollution reaching limits of detection up to sub ng L(-1). Alternative to analytical measurements, occurrence models can provide risk managers with a very interesting approach for estimating environmental concentrations from real or hypothetical scenarios. The most representative prioritization schemes used for issuing lists of concerning chemicals have also been examined and put in the context of existing environmental policies for protection strategies and regulations. Finally, new challenges in the field of risk-assessment have been outlined, including those posed by new materials (i.e., nanomaterials), transformation products, multi-chemical exposure, or extension of the risk assessment process to the whole ecosystem.

Alpha-amylase starch binding domains: cooperative effects of binding to starch granules of multiple tandemly arranged domains.

The Lactobacillus amylovorus alpha-amylase starch binding domain (SBD) is a functional domain responsible for binding to insoluble starch. Structurally, this domain is dissimilar from other reported SBDs because it is composed of five identical tandem modules of 91 amino acids each. To understand adsorption phenomena specific to this SBD, the importance of their modular arrangement in relationship to binding ability was investigated. Peptides corresponding to one, two, three, four, or five modules were expressed as His-tagged proteins. Protein binding assays showed an increased capacity of adsorption as a function of the number of modules, suggesting that each unit of the SBD may act in an additive or synergic way to optimize binding to raw starch.

[Results of a comprehensive workplace program for the prevention and treatment of smoking addiction]. / Resultados de un programa integral de prevención y tratamiento del tabaquismo en el entorno laboral.

OBJECTIVES: To assess a comprehensive smoking prevention and treatment program in an electrical appliances company with 1600 employees. MATERIAL AND METHODS: The program included smoking restrictions with the designation of smoking areas and the offer of smoking cessation treatment for the smokers affected. Study variables were age, sex, nicotine dependence (Fagerström Test), carbon monoxide in expired air, adherence to therapy, and smoking abstinence at 1 week, 1 month, 3 months (end of treatment), and 6 months. Successful smoking abstinence was defined as continuous abstinence from the beginning of treatment. RESULTS: Smoking prevalence was 34.8% and 19.5% of smokers requested treatment (77.4% men and 22.6% women). Mean (SD) age was 41.3 (10.3) years. Mean score of nicotine dependence was 5.3 (2.6) and the mean quantity of carbon monoxide in expired air was 35.6 (23.7) ppm. Adherence to therapy was good in 80% of patients. Rate of abstinence was 57.5% at 6 months, signifying a 4% reduction in prevalence. CONCLUSIONS: Workplace smoking cessation programs reduce prevalence and facilitate the establishment of smoking restrictions at the worksite. Companies are convenient settings for the implementation of programs aimed at smoking prevention and treatment.

Resultados de un programa integral de prevención y tratamiento del tabaquismo en el entorno laboral / Results of comprehensive workplace`program for the prevention and treatment of smoking addiction

OBJETIVOS: Evaluar un programa integral de prevención y tratamiento del tabaquismo en una empresa de electrodomésticos con 1.600 trabajadores. MATERIAL Y MÉTODOS: El programa incluyó restricción para fumar con delimitación de espacios para fumadores y oferta de deshabituación tabáquica a los fumadores afectados. Las variables de estudio fueron: edad, sexo, dependencia a la nicotina (test de Fagerström), monóxido de carbono en aire espirado, cumplimiento del tratamiento y abstinencia en el consumo de tabaco a la semana, al mes, a los 3 (fin del tratamiento) y a los 6 meses. Se definió como éxito la abstinencia mantenida en el consumo de tabaco desde el inicio del tratamiento. RESULTADOS: La prevalencia de tabaquismo era del 34,8%. Solicitaron tratamiento el 19,5% de los fumadores (un 77,4% eran varones y el 22,6%, mujeres). La media de edad (± desviación estándar) era de 41,3 ± 10,3 años. El valor medio de la dependencia a la nicotina fue de 5,3 ± 2,6 puntos y la media de monóxido de carbono en aire espirado de 35,6 ± 23,7 ppm. El cumplimiento del tratamiento fue bueno en el 80% de los casos. El índice de abstinencia fue del 57,5% a los 6 meses, lo que supone una reducción de la prevalencia del 4%. CONCLUSIONES: Las intervenciones sobre el tabaquismo en el entorno laboral reducen la prevalencia y facilitan establecer restricciones del consumo en el lugar de trabajo. La empresa representa un escenario oportuno para realizar intervenciones dirigidas a la prevención y tratamiento del tabaquismo

OBJECTIVES: To assess a comprehensive smoking prevention and treatment program in an electrical appliances company with 1600 employees. MATERIAL AND METHODS: The program included smoking restrictions with the designation of smoking areas and the offer of smoking cessation treatment for the smokers affected. Study variables were age, sex, nicotine dependence (Fagerström Test), carbon monoxide in expired air, adherence to therapy, and smoking abstinence at 1 week, 1 month, 3 months (end of treatment), and 6 months. Successful smoking abstinence was defined as continuous abstinence from the beginning of treatment. RESULTS: Smoking prevalence was 34.8% and 19.5% of smokers requested treatment (77.4% men and 22.6% women). Mean (SD) age was 41.3 (10.3) years. Mean score of nicotine dependence was 5.3 (2.6) and the mean quantity of carbon monoxide in expired air was 35.6 (23.7) ppm. Adherence to therapy was good in 80% of patients. Rate of abstinence was 57.5% at 6 months, signifying a 4% reduction in prevalence. CONCLUSIONS: Workplace smoking cessation programs reduce prevalence and facilitate the establishment of smoking restrictions at the worksite. Companies are convenient settings for the implementation of programs aimed at smoking prevention and treatment

[Smoking habits among sixth-year medical students in Spain]. / Consumo de tabaco en estudiantes de sexto curso de medicina de España.

OBJECTIVE: To describe and analyze the smoking habits of sixth-year Spanish medical students. MATERIAL AND METHODS: The target population of this descriptive cross-sectional study was students completing their sixth year in Spanish medical schools. An anonymous, self-administered questionnaire was sent to the students' homes by ordinary mail. The relationships between the variables were analyzed using contingency tables, the chi2 test, the Student t test, and analysis of variance with a significance level of P< .05. The software package was SPSS. RESULTS: A total of 3840 questionnaires were distributed to students, and 1340 were returned completed (34.9%). Of the respondents, 27% were smokers (8.7% smoked only on weekends, and 18.3% were daily smokers). The mean (SD) number of cigarettes smoked per day was 10.54 (7.89). Consumption was significantly higher among men than among women. The mean age of initiation was 17.20 years. Of the students who were smokers, 32.54% stated that they had started smoking during their medical studies. The percentage of smokers who stated that they wanted to quit was 76.3%, and 56.6% said that they had already made at least one quit attempt. CONCLUSIONS: It is cause for concern that a large number of students start smoking after they enter medical school. One of the reasons for this is the lack of concern about smoking as a health problem within medical schools. The smoking habits of medical students are affected by the same phenomena that affect those of the general public, such as the increase in the number of women smokers, the influence of sociocultural factors, and the increasingly broader age range of initiation. The lower prevalence of smoking among medical students with respect to other populations is probably due to the fact that, in general, these students have better health habits than the general public, and/or the reasons that led them to study medicine also make them disinclined to smoke.