Larrea divaricata a native Argentine plant with potential activity against SARS-CoV-2? / ¿Larrea divaricata una planta nativa argentina con actividad potencial sobre SARS-CoV-2?

Larrea divaricata Cav. is an autochthonous South American plant popularly used in inflammatory and infectious diseases with reported anti - inflammatory, immunomodulatory, antimicrobial and antioxidant activities. Covid - 19 is an infection ca used by the severe acute respiratory syndrome coronavirus 2 (SARS - CoV - 2). This virus can cause pneumonia and even death in about 5% of the cases. The objective of the article was to demonstrate, through a literature review, that L. divaricata has sufficie nt attributes to be assayed against SARS - CoV - 2. For this, the chemical composition, reported activities and docking studies were taken into account. This review demonstrated that the plant extracts are capable of inhibiting the proliferation of fungi, bact eria and viruses and that they exert anti - inflammatory and immunomodulatory actions in different " in vitro " and " in vivo " models. These results suggest that the plant is a good candidate to be studied for the prevention and/or treatment of SARS - CoV - 2.

Larrea divaricata Cav. es una planta autóctona Sudamericana, utilizada popularmente en enfermedades inflamatorias e infecciosas, con activida d anti - inflamatoria, inmunomoduladora, antimicrobiana y antioxidante reportada. El Covid - 19 es una infección causada por una cepa de coronavirus, SARS - CoV - 2 (coronavirus tipo 2 causante del síndrome respiratorio agudo severo). Este virus puede originar neu monía e incluso la muerte en alrededor del 5% de los casos. Nuestro objetivo fue demostrar, a través de una revisión bibliográfica, que esta planta tiene atributos suficientes para ser ensayada en estudios contra SARS - CoV - 2. Se tuvo en cuenta la composici ón química, los antecedentes científicos y los estudios de acoplamiento molecular. Esta revisión permitió demostrar que extractos de la planta son capaces de inhibir la proliferación de hongos, bacterias y virus y que presentan acción anti - inflamatoria en diferentes modelos " in vitro " e " in vivo ", lo que los hace candidatos a ser estudiados en la prevención y/o tratamiento de la infección contra SARS - CoV - 2.

Suppressed-scattering spectral windows for radiative cooling applications.

The scattering of light by resonant nanoparticles is a key process for enhancing the solar reflectance in daylight radiative cooling. Here, we investigate the impact of material dispersion on the scattering performance of popular nanoparticles for radiative cooling applications. We show that, due to material dispersion, nanoparticles with a qualitatively similar response at visible frequencies exhibit fundamentally different scattering properties at infrared frequencies. It is found that dispersive nanoparticles exhibit suppressed-scattering windows, allowing for selective thermal emission within a highly reflective sample. The existence of suppressed-scattering windows solely depends on material dispersion, and they appear pinned to the same wavelength even in random composite materials and periodic metasurfaces. Finally, we investigate calcium-silicate-hydrate (CSH), the main phase of concrete, as an example of a dispersive host, illustrating that the co-design of nanoparticles and host allows for tuning of the suppressed-scattering windows. Our results indicate that controlled nanoporosities would enable concrete with daylight passive radiative cooling capabilities.

Fractura de astrágalo asociado a fractura del cuboides en un niño de 9 años: reporte de caso / Talar fracture associated with cuboid fracture in a 9-year-old boy: case report / Fratura do tálus associada à fratura do cubóide em menino de 9 anos: relato de caso

Introducción: El astrágalo tiene una anatomía única y juega un papel fundamental en la función del tobillo y pie. Las fracturas de astrágalo se consideran una urgencia ortopédica especialmente las fracturas de cuello desplazadas, debido al alto riesgo de necrosis avascular. Sin embargo, estas son raras en los niños con una prevalencia estimada del 0,008% de todas las fracturas pediátricas. Las fracturas del cuello del astrágalo se asocian con una alta tasa de complicaciones, entre las más importantes se destacan la artrosis postraumática y la necrosis avascular. Éstas están relacionadas principalmente con el grado de desplazamiento inicial del cuello del astrágalo y la incidencia puede ser del 100%. Objetivos: Los objetivos del presente trabajo son demostrar la evolución de un paciente con una patología poco frecuente, con una asociación lesional no reportada hasta el momento y realizar una revisión bibliográfica del tema. Material y métodos: Se evaluó de forma retrospectiva un paciente de sexo masculino de 9 años con una luxo-fractura de cuello de astrágalo de pie izquierdo asociado a una fractura de cuboides. Se evaluaron los resultados clínicos radiológicos y funcionales luego de 3 años de evolución. Resultados: En nuestro caso se realizó reducción abierta y fijación percutánea. Se logró una excelente consolidación ósea sin complicaciones y con buena funcionalidad del tobillo luego de 3 años de seguimiento. Se realizó la escala AOFAS obteniendo una puntuación de 93/100. No presentó limitaciones en cuanto al dolor, con un total de 40 puntos, no mostró limitaciones en cuanto a la función, con un total de 45 puntos. Observamos una leve desaxación en valgo del retropie, asintomático, con un total de 8 puntos. Conclusiones: Las fracturas del astrágalo son raras en la población pediátrica pero pueden ocasionar complicaciones graves. En nuestro caso observamos una fractura grave, con una asociación lesional no descrita hasta el momento, que presentó muy buena evolución, con una consolidación ósea, sin complicaciones y con buen resultado funcional a los 3 años de la cirugía. Al tratarse de una patología muy poco frecuente y rara, la bibliografía revisada es en general de baja evidencia científica y se basa en su mayoría en reporte de casos clínicos, excepto una revisión sistemática con bajo numero de pacientes.

Introduction: The talus has a unique anatomy and plays a fundamental role in the function of the ankle and foot. Talar fractures are considered an orthopedic emergency, especially displaced neck fractures, due to the high risk of avascular necrosis. However, these are rare in children with an estimated prevalence of 0.008% of all pediatric fractures. Talar neck fractures are associated with a high rate of complications, the most important of which include post-traumatic osteoarthritis and avascular necrosis. These are mainly related to the degree of initial displacement of the talar neck and the incidence can be 100%. Objectives: The objectives of this work are to demonstrate the evolution of a patient with a rare pathology, with an injury association not reported so far and to carry out a bibliographic review of the topic. Material and methods: A 9-year-old male patient with a talar neck fracture dislocation of the left foot associated with a cuboid fracture was retrospectively evaluated. Clinical, radiological and functional results were evaluated after 3 years of evolution. Results: In our case, open reduction and percutaneous fixation were performed. Excellent bone union was achieved without complications and with good ankle functionality after 3 years of follow-up. The AOFAS scale was performed, obtaining a score of 93/100. It did not present limitations in terms of pain, with a total of 40 points, it did not show limitations in terms of function, with a total of 45 points. We observed a slight valgus dexation of the hindfoot, asymptomatic, with a total of 8 points. Conclusions: Talar fractures are rare in the pediatric population but can cause serious complications. In our case we observed a serious fracture, with an injury association not described until now, which presented a very good evolution, with bone consolidation, without complications and with good functional result 3 years after surgery. As it is a very infrequent and rare pathology, the literature reviewed is generally of low scientific evidence and is based mostly on clinical case reports, except for a systematic review with a low number of patients.

Introdução: O tálus possui anatomia única e desempenha papel fundamental na função do tornozelo e do pé. As fraturas do tálus são consideradas uma emergência ortopédica, principalmente as fraturas deslocadas do colo, devido ao alto risco de necrose avascular. No entanto, estas são raras em crianças, com uma prevalência estimada de 0,008% de todas as fraturas pediátricas. As fraturas do colo do tálus estão associadas a uma alta taxa de complicações, sendo as mais importantes a osteoartrite pós-traumática e a necrose avascular. Estas estão relacionadas principalmente ao grau de deslocamento inicial do colo do tálus e a incidência pode ser de 100%. Objetivos: Os objetivos deste trabalho são demonstrar a evolução de um paciente com patologia rara, com associação de lesão até o momento não relatada e realizar uma revisão bibliográfica sobre o tema. Material e métodos: Foi avaliado retrospectivamente um paciente do sexo masculino, 9 anos de idade, com fratura luxação do colo do tálus do pé esquerdo associada a fratura do cuboide. Os resultados clínicos, radiológicos e funcionais foram avaliados após 3 anos de evolução. Resultados: No nosso caso foi realizada redução aberta e fixação percutânea. Excelente consolidação óssea foi alcançada sem complicações e com boa funcionalidade do tornozelo após 3 anos de acompanhamento. Foi realizada a escala AOFAS, obtendo pontuação de 93/100. Não apresentou limitações em termos de dor, com um total de 40 pontos, não apresentou limitações em termos de função, com um total de 45 pontos. Observamos leve dexação em valgo do retropé, assintomática, com total de 8 pontos. Conclusões: As fraturas do tálus são raras na população pediátrica, mas podem causar complicações graves. No nosso caso observamos uma fratura grave, com associação de lesão até então não descrita, que apresentou evolução muito boa, com consolidação óssea, sem complicações e com bom resultado funcional 3 anos após a cirurgia. Por se tratar de uma patologia muito pouco frequente e rara, a literatura revista é geralmente de baixa evidência científica e baseia-se maioritariamente em relatos de casos clínicos, exceto uma revisão sistemática com um número reduzido de doentes.

Anti-hyperglycaemic effect and nutritional properties of an aqueous extract of Larrea divaricata Cav. (jarilla) in streptozotocin-induced diabetes in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Larrea divaricata Cav. (Zygophyllaceae) (jarilla) is a native plant of South America widely distributed across Argentina and used in popular medicine to treat diabetes and hypercholesterolemia by the Diaguita-Calchaquí, Amaichas, and Quilmes indigenous communities and by non-indigenous population (criollos) of Calamuchita, in the province of Córdoba, Argentina. L. divaricata has also proved to have anti-inflammatory properties. However, the antidiabetic effects and the nutritional properties of the aqueous extract (AE) of this plant remain to be scientifically determined. AIM OF THE STUDY: The aim of the present work was to evaluate the capacity of an aqueous extract of L. divaricata (AE) and its main compound nordihydroguaiaretic acid (NDGA) to modulate the glucose, cholesterol, triglycerides and oxidative stress levels in STZ-induced diabetes in mice. The general objective of the present work was to search for extracts that can be used as adjuvant therapy in for diabetes. The suitability of the extract to be used as a dietary supplement was also assessed by determining the proximate amount of fibre, lipids, proteins, and minerals. MATERIALS AND METHODS: Diabetes was induced in mice by administration of streptozotocin (STZ). AE and NDGA were administered by the oral route. The animals' glycaemia was periodically monitored in blood samples obtained from the tail vein. The glucose dehydrogenase method was used. The effect of the AE on cholesterol, triglycerides, oxidative stress, lipid peroxidation and reduced glutathione (GSH) levels were determined in plasma samples by spectrophotometric assays. RESULTS: In STZ-treated mice, AE significantly decreased glucose (33%, ****p < 0.0001) and cholesterol levels (32%, **p < 0.01). AE and NDGA decreased lipid peroxidation (30% and 38%, respectively, ****p < 0.0001), and increased GSH levels (20%, **p < 0.01). The effects of AE on glucose and lipid levels could not be ascribed to NDGA; however, this compound was involved in the extract antioxidant effects. The overall effects of AE were probably related to its antioxidant activity and to the anti-hyperglycaemic effect mainly mediated by flavonoids, fibre (carbohydrates) and mineral elements such as potassium, calcium, magnesium, and zinc. The AE protein content also confers the extract nutritional properties. CONCLUSIONS: These results support the hypothesis that AE could be used as a therapeutic adjuvant or as a nutritional supplement to control glucose levels and lipid metabolism in metabolic syndrome-associated diseases. Moreover, these results scientifically reinforce the popular use of the plant.

Larrea divaricata: anti-inflammatory and antioxidant effects of on macrophages and low density lipoproteins.

BACKGROUND: The oxidized low density lipoprotein (ox-LDL) contributes to inflammation and oxidative stress through the activation of macrophages under hyperglycemia contributing to the development of diabetes mellitus and to atherosclerosis. Plants are a source of effective and innocuous antioxidants. Larrea divaricata Cav. (Zygophyllaceae) is used in Argentina folk medicine for its anti-inflammatory properties. METHODS: The aim of this work was to study the antioxidant and anti-inflammatory effects of the aqueous extract (AE) of L. divaricata on macrophages under glucose stimulation and on human LDL and HDL particles under free radical generators. RESULTS: AE reduced the lipid peroxidation (17%), nitric oxide (NO) (47-50%), tumor necrosis factor-α (TNF-α) (32%) and free radicals (50%) induced by glucose on macrophages. Also prevented HDL nitration (28%), thus preserving its function and structure and inhibited LDL oxidation. The effect on the nitrosative stress was mainly driven by nordihydroguaiaretic acid (NDGA). CONCLUSIONS: These results suggest a potential usefulness of AE as an adjuvant phytotherapy in patients with diabetes mellitus and atherosclerosis.

Antiproliferative activity of aqueous and polyphenol-rich extracts of Larrea divaricata Cav. on a melanoma cell line.

Most of the deaths from skin cancer are caused by melanoma, a malignancy in which STAT3 plays a crucial role. The inhibition of STAT3 is considered a potential target to induce cell death, tumor regression and metastasis inhibition. The objective of this work was to evaluate the activity of the aqueous extract of Larrea divaricata (Aq), a fraction rich in polyphenols (EA),and the isolated compound quercetin-3-methyl ether (Q3ME) on B16F10 melanoma cells. The effects of Aq, EA and Q3ME were assessed on B16F10 cells by determining the proliferation, viability, apoptosis induction and the expression and phosphorylation of STAT3. The phytochemical composition of the extracts was determined by High Performance Liquid Chromatography. Aq, EA and Q3ME presented antiproliferative activity on B6F10 cells through p-STAT3 inhibition and early and late apoptosis induction (EC50 EA= ≤0.1 µg/ml; Aq= 316 ± 30 µg/ml; Q3ME= <0.1 µg/ml). L. divaricata could be considered for the development of adjuvant phytotherapies in melanoma treatment.

Revisión bibliográfica para determinar calidad de vida y satisfacción, de pacientes con encefalopatía crónica no evolutiva sometidos a cirugía multinivel / Literature review to determine quality of life and satisfaction of patients with non-progressive chronic encephalopathy undergoing multilevel surgery / Revisão da literatura para determinar a qualidade de vida e a satisfação de pacientes com encefalopatia crônica não progressiva submetidos à cirurgia multinível

La calidad de vida relacionada a la salud se refiere a la percepción que tienen los sujetos sobre su estado de salud, y las actividades realizadas para mantener o mejorar la salud en su contexto sociocultural. La encefalopatía crónica no evolutiva es una lesión estática no progresiva que constituye la primera causa de disfunción motora en niños. La historia natural de la marcha y la función en esta población es el deterioro con el paso del tiempo. El tratamiento estándar es la cirugía multinivel. Objetivo: determinar los resultados sobre satisfacción, percepción de función y percepción de calidad de vida en niños con encefalopatía crónica no evolutiva luego de realizada la cirugía multinivel. Metodología: se realizó una revisión bibliográfica de la literatura. Resultados: se seleccionaron 10 artículos de metodologías heterogéneas que cumplen con los criterios de inclusión. Los resultados arrojan una mejora en la percepción de función y calidad de vida. Conclusiones: es necesario ahondar más en la investigación sobre los resultados de la cirugía y en abordajes que incorporen la mirada de los pacientes y sus cuidadores.

Health-related quality of life refers to the perception that subjects have about their state of health, and the activities carried out to maintain or improve health in their sociocultural context. Chronic non-progressive encephalopathy is a non-progressive static lesion that is the leading cause of motor dysfunction in children. The natural history of gait and function in this population is deterioration over time. The standard treatment is multilevel surgery. Objective: to determine the results on satisfaction, perception of function and perception of quality of life in children with non-progressive chronic encephalopathy after multilevel surgery. Methodology: a bibliographic review of the literature was carried out. Results: 10 articles with heterogeneous methodologies that meet the inclusion criteria were selected. The results show an improvement in the perception of function and quality of life. Conclusions: it is necessary to delve deeper into research on the results of surgery and on approaches that incorporate the point of view of patients and their caregivers.

A qualidade de vida relacionada à saúde refere-se à percepção que os sujeitos têm sobre seu estado de saúde e as atividades realizadas para manter ou melhorar a saúde em seu contexto sociocultural. A encefalopatia crônica não progressiva é uma lesão estática não progressiva que é a principal causa de disfunção motora em crianças. A história natural da marcha e da função nesta população é a deterioração ao longo do tempo. O tratamento padrão é a cirurgia multinível. Objetivo: determinar os resultados sobre satisfação, percepção de função e percepção de qualidade de vida em crianças com encefalopatia crônica não progressiva após cirurgia multinível. Metodologia: foi realizada uma revisão bibliográfica da literatura. Resultados: foram selecionados 10 artigos com metodologias heterogêneas que atendem aos critérios de inclusão. Os resultados mostram uma melhora na percepção de função e qualidade de vida. Conclusões: é necessário aprofundar as pesquisas sobre os resultados da cirurgia e sobre as abordagens que incorporem o olhar do paciente e de seu cuidador.

Fracturas metafisarias de radio distal desplazadas en el esqueleto en crecimiento: ¿cuál es el mejor método terapéutico? revisión bibliográfica sistematizada / Displaced distal radius metaphyseal fractures in the growing skeleton: what is the best therapeutic method? systematized bibliographic review / Fraturas metafisárias do rádio distal deslocadas no esqueleto em crescimento: qual é o melhor método terapêutico? revisão bibliográfica sistematizada

Introducción: Las fracturas metafisarias de radio distal son las fracturas más frecuentes en la edad pediátrica, siendo 30% del total de las mismas. Mantener la reducción de las fracturas desplazadas no siempre es posible: el re-desplazamiento es la principal complicación de estas lesiones. Clásicamente se realizó tratamiento con maniobra y yeso, aunque en los últimos años se asoció fijación con Kirschner wire (Kw) en búsqueda de disminuir el re-desplazamiento. El objetivo de nuestro trabajo es identificar factores de riesgo en búsqueda de realizar el mejor tratamiento siendo lo menos agresivo posible. Materiales y métodos: Se realizó una búsqueda sistematizada a través del buscador electrónico PubMed. La misma alcanzó un total de 4594 artículos, que de acuerdo con los criterios de inclusión y exclusión se seleccionaron 15 trabajos para realizar nuestra revisión bibliográfica. Resultados: Se destaca que la mayoría de los artículos encontrados son de nivel de evidencia III y IV. Nuestra búsqueda refleja un índice de re-desplazamiento entre 20-39% mediante yeso a las 2 semanas; asi como un índice de re-manipulación entre el 5-10 % del total de las fracturas desplazadas. La mayoría de los estudios analizados intentan identificar los factores de riesgo más importantes para el re-desplazamiento de las fracturas, de lo que se destacan el grado de desplazamiento inicial de la fractura y la reducción lograda de la misma. A su vez, otros artículos valoran los resultados del tratamiento mediante estabilización con yeso o fijación mediante Kirschner wire. Conclusión: el desplazamiento inicial de la fractura y la reducción lograda en block quirúrgico (BQ) son los factores de riesgo más importantes para el re-desplazamiento. Si bien la técnica de enyesado no es considerado una variable estadísticamente significativa, es considerada una variable importante en cuanto al pronóstico de la lesión, destacando al moldeado de 3 puntos como principal índice a considerar. Se considera aconsejable asociar un Kw en aquellas fracturas cabalgadas en las que no se logra una reducción anatómica en block quirúrgico.

Introduction: Distal radius metaphyseal fractures are the most frequent fractures in pediatric age, accounting for 30% of the total. Maintaining the reduction of displaced fractures is not always possible: re-displacement is the main complication of these injuries. Classically, treatment was performed with a maneuver and a cast, although in recent years fixation with Kirschner wire (Kw) has been associated in search of reducing re-displacement. The objective of our work is to identify risk factors in search of the best treatment while being the least aggressive possible. Materials and methods: A systematic search was carried out using the PubMed electronic search engine. It reached a total of 4594 articles, which according to the inclusion and exclusion criteria, 15 papers were selected for our bibliographic review. Results: It should be noted that most of the articles found are level of evidence III and IV. Our search reflects a re-displacement rate between 20-39% using a cast at 2 weeks; as well as a re-manipulation index between 5-10% of all displaced fractures. Most of the studies analyzed attempt to identify the most important risk factors for the re-displacement of fractures, of which the degree of initial displacement of the fracture and the reduction achieved are highlighted. In turn, other articles assess the results of treatment by stabilization with plaster or fixation with Kirschner wire. Conclusion: the initial displacement of the fracture and the reduction achieved in the surgical block (BQ) are the most important risk factors for re-displacement. Although the casting technique is not considered a statistically significant variable, it is considered an important variable in terms of the prognosis of the injury, highlighting the 3-point casting as the main index to be considered. It is considered advisable to associate a Kw in those mounted fractures in which an anatomical reduction in surgical block is not achieved.

Introdução: As fraturas metafisárias do rádio distal são as mais frequentes na idade pediátrica, correspondendo a 30% do total. Manter a redução das fraturas desviadas nem sempre é possível: o deslocamento é a principal complicação dessas lesões. Classicamente, o tratamento era realizado com manobra e gesso, embora nos últimos anos a fixação com fio de Kirschner (Kw) tenha sido associada na busca pela redução do deslocamento. O objetivo do nosso trabalho é identificar os fatores de risco em busca do melhor tratamento sendo o menos agressivo possível. Materiais e métodos: uma busca sistemática foi realizada usando o mecanismo de busca eletrônico PubMed. Chegou-se a um total de 4.594 artigos, que de acordo com os critérios de inclusão e exclusão, foram selecionados 15 artigos para nossa revisão bibliográfica. Resultados: Ressalta-se que a maioria dos artigos encontrados são de nível de evidência III e IV. Nossa pesquisa reflete uma taxa de re-deslocamento entre 20-39% usando um gesso em 2 semanas; bem como um índice de remanipulação entre 5-10% de todas as fraturas deslocadas. A maioria dos estudos analisados ​​busca identificar os fatores de risco mais importantes para o deslocamento das fraturas, que incluem o grau de deslocamento inicial da fratura e a redução alcançada. Por sua vez, outros artigos avaliam os resultados do tratamento com estabilização gessada ou fixação com fio de Kirschner. Conclusão: o deslocamento inicial da fratura e a redução alcançada no bloqueio cirúrgico (QB) são os fatores de risco mais importantes para o deslocamento. Embora a técnica de gesso não seja considerada uma variável estatisticamente significativa, é considerada uma variável importante em termos de prognóstico da lesão, destacando-se o gesso em 3 pontos como o principal índice a ser considerado. Considera-se aconselhável associar um Kw nas fraturas montadas em que não se consegue redução anatômica no bloqueio cirúrgico.

Larrea divaricata Cav. aqueous extract and nordihydroguariaretic acid modulate oxidative stress in submandibular glands of diabetic rats: a buccal protective in diabetes.

BACKGROUND: Oxidative stress is an imbalance between the levels of reactive oxygen species (ROS), reactive nitrogen species (RNS) and endogenous antioxidants. The aetiology and pathogenesis of several oral diseases are attributed to this process. The antioxidant enzymes secreted in the saliva by submandibular glands maintain oral health through the scavenging of ROS. The objective of this work was to study the capacity of an aqueous extract of L. divaricata (AE), and its majority compound, nordihydroguariaretic acid (NDGA), to modulate the pro-oxidant/antioxidant status in submandibular glands in a model of oxidative stress induced by streptozotocin (STZ) in rats. METHODS: To induce oxidative stress with STZ, a group of animals was treated i.p. with 1 X PBS (control group) and other group was injected i.p. once with STZ (60 mg/kg). Ten days after the treatment, blood samples were taken from the tail vain to determine the glucose levels. Animals with glucose values ≥300 mg/ml were selected. The submandibular glands of control and STZ treated animals were incubated with either the AE (500 µg/ml) or with NDGA (1.5 µg/ml), and the content of malondialdehyde (MDA), protein carbonyl groups, ROS and RNS, and the activity and expression of peroxidase (Px), superoxide dismutase (SOD) and inducible nitric oxide synthase (iNOS) were assayed. RESULTS: AE decreased the levels of MDA (##P < 0.01) and protein carbonyl groups (#P < 0.05), and modulated the levels of ROS such as hydrogen peroxide (H2O2)(##P < 0.01), superoxide anion (O2.-) (#P < 0.05) and nitric oxide (NO) (#P < 0.05) in relation to the modulation of Px and iNOS expression. NDGA was found to be involved in these effects. CONCLUSIONS: The antioxidant activity of the AE in the submandibular glands would allow the maintenance of the antioxidant pool to prevent oral oxidative diseases.

Metamaterial for elastostatic cloaking under thermal gradients.

We introduce the optimization-based method for the design of thermo-mechanical metamaterials and, particularly, for the elastostatic cloaking under thermal loads. It consists of solving a large-scale, nonlinear constrained optimization problem, where the objective function is the error in the cloaking task accomplishment. The design variables define the required metamaterial distribution. In this way, the cloaking task is accomplished, if not exactly, optimally. Further, the design variables dictate how to fabricate the metamaterial, avoiding the uncertainty of simultaneously mimicking several thermal and mechanical effective properties, as required by transformation-based metamaterial design methods.

Food preservation by Larrea divaricata extract: participation of polyphenols.

The aim of this study was to evaluate the antioxidant and protease inhibitor capacities on eggs and milk protein of a nor-dihydroguaiaretic (NDGA)-standardized aqueous extract of Larrea divaricata (AE) and to analyze the participation of polyphenols as NDGA in these actions. NDGA was determined by high-performance liquid chromatography; flavonoids and polyphenols were quantified by spectrophotometric methods as well as inhibition of lipid peroxidation, proteinase inhibitor capacity, advanced glycation end products (AGES) formation, and inhibition of albumin denaturation. The extract protected food for oxidative damage by preventing malondialdehyde formation in egg yolk and by preventing AGE formation in completely cooked eggs, also impeded albumin denaturation, and casein hydrolysis induced by trypsin and heat. Polyphenols, especially flavonoids and NDGA, were involved in these actions.

Optimization-based design of an elastostatic cloaking device.

We present a new method for the design of devices to manipulate the displacement field in Elastic materials. It consists of solving a nonlinear optimization problem where the objective function defines the error in matching a desired displacement field, and the design variables determine the required material distribution within the device. In order to facilitate fabrication, the material at a given point of the device is chosen from a set of predefined materials, giving raise to a discrete optimization problem that is converted into a continuous one using the Discrete Material Optimization technique. The candidate materials maybe simple, isotropic materials, but the device made of them behaves as a whole as a metamaterial, enabling the manipulation of the displacement field in ways that are inconceivable in nature. As an example of application, a device for elastostatic cloaking or unfeelability is designed.

Comparative study of the polyphenol content-related anti-inflammatory and antioxidant activities of two Urera aurantiaca specimens from different geographical areas.

BACKGROUND: Urera aurantiaca is an Argentinean species that has been traditionally used to treat symptoms of inflammation. The aim of this study was to determine and compare the anti-inflammatory and antioxidant effects of two specimens of Urera aurantiaca obtained in the provinces of Salta and Misiones, which are two different geographical areas of Argentina. METHODS: The anti-inflammatory activity of the extracts was tested in LPS-stimulated macrophages through the DPPH radical scavenging activity, the SOD-like activity, the reducing power and the inhibition of lipid peroxidation. The anti-inflammatory activity was also evaluated by the inhibition of albumin denaturation and proteinase inhibitory action tests. The total polyphenols, flavonoids and tannins content were quantified. RESULTS: Both extracts were able to reduce the augmented NO release in LPS-activated macrophages and showed antioxidant and in vitro anti-inflammatory activities. The polyphenols content was higher in the extract obtained from the specimen from Salta than in that obtained in Misiones. This finding accounts for the higher anti-inflammatory and antioxidant properties obtained with the former. CONCLUSION: The differences in chemical composition and the biological activities observed between the extracts are probably related to the different environmental conditions found in both provinces.

Development of pH-responsive biopolymer-silica composites loaded with Larrea divaricata Cav. extract with antioxidant activity.

A detailed study of biomaterials is mandatory to comprehend their feasible biomedical applications in terms of drug delivery and tissue regeneration. Particularly, mucoadhesive biopolymers such as chitosan (chi) and carboxymethylcellulose (CMC) have become interesting biomaterials regards to their biocompatibility and non-toxicity for oral mucosal drug delivery. In this work, pH-responsive biopolymer-silica composites (Chi-SiO2, Chi-CMC-SiO2) were developed. These two types of composites presented a different swelling behavior due to the environmental pH. Moreover, the nanocomposites were loaded with aqueous Larrea divaricata Cav. extract (Ld), a South American plant which presents antioxidant properties suitable for the treatment of gingivoperiodontal diseases. Chi-CMC-SiO2 composites showed the highest incorporation and reached the 100% of extract release in almost 4 days while they preserved their antioxidant properties. In this study, thermal and swelling behavior were pointed out to show the distinct water-composite interaction and therefore to evaluate their mucoadhesivity. Furthermore, a cytotoxicity test with 3T3 fibroblasts was assessed, showing that in both composites the addition of Larrea divaricata Cav. extract increased fibroblast proliferation. Lastly, preliminary in vitro studies were performed with simulated body fluids. Indeed, SEM-EDS analysis indicated that only chi-SiO2 composite may provide an environment for possible biomineralization while the addition of CMC to the composites discouraged calcium accumulation. In conclusion, the development of bioactive composites could promote the regeneration of periodontal tissue damaged throughout periodontal disease and the presence of silica nanoparticles could provide an environment for biomineralization.

Stability of an Aqueous Extract of Larrea divaricata Cav. during a Simulated Digestion Process.

Larrea divaricata Cav. (Zygophyllaceae) is a South American plant widely distributed in Argentina that is used in folk medicine to treat inflammatory diseases. The aqueous extract is known to have well-documented biological activities such as antitumour, immunomodulatory, antimicrobial, antiinflammatory and antioxidant. However, its stability in gastrointestinal fluids is unknown. The latter is an important factor to assure the bioavailability of plant extracts intended to be administered via the oral route. The aim of this work was to study the stability of a lyophilized aqueous extract of L. divaricata compressed as a pill. To this end, the main polyphenol compound found in the extract, that is, the nordihydroguaiaretic acid, the total polyphenols and flavonoids content and the antioxidant activity such as diphenylpicrylhydrazyl scavenger activity and reducing power were assayed after subjecting the extract to different incubation times in simulated digestive fluids. The HPLC and spectroscopic methods were employed. Although the levels of polyphenols and flavonoids decreased upon incubation in gastric and intestinal fluids, the extract maintained its antioxidant activity related to the presence of nordihydroguaiaretic acid. These results are promising and encourage the potential use of the extract by the oral route as a supplement or phytomedicine with antioxidant activity. Copyright © 2017 John Wiley & Sons, Ltd.

Optimization-based design of heat flux manipulation devices with emphasis on fabricability.

In this work, we present a new method for the design of heat flux manipulating devices, with emphasis on their fabricability. The design is obtained as solution of a nonlinear optimization problem where the objective function represents the given heat flux manipulation task, and the design variables define the material distribution in the device. In order to facilitate the fabrication of the device, the material at a given point is chosen from a set of predefined metamaterials. Each candidate material is assumed to be a laminate of materials with high conductivity contrast, so it is a metamaterial with a highly anisotropic effective conductivity. Following the discrete material optimization (DMO) approach, the fraction of each material at a given finite element of the mesh is defined as a function of continuous variables, which are ultimately the design variables. This DMO definition forces the fraction of each candidate to tend to either zero or one at the optimal solution. As an application example, we designed an easy-to-make device for heat flux concentration and cloaking.

Optimization-based design of a heat flux concentrator.

To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it.

Prevention of hydrogen peroxide-induced red blood cells lysis by Ilex paraguariensis aqueous extract: participation of phenolic and xanthine compounds.

The fresh leaves and stems of Ilex paraguariensis (Aquifoliaceae) are employed to prepare the commercial product used in North-eastern Argentina, Southern Brazil and Eastern Paraguay named yerba maté. The presence of polyphenols and xanthines, which present antioxidant activity, has been described in I. paraguariensis. In living organism, reactive oxygen species can cause tissue damage affecting erythrocyte membranes leading to hemolysis. The aim of this work was to evaluate the protective effect of an aqueous extract of I. paraguariensis (green leaves) on the hemolysis of red blood cells induced by hydrogen peroxide and to correlate this activity with the enzymatic activity related to hydrogen peroxide metabolism. The antioxidant activity of chlorogenic acid and caffeine was also analysed to evaluate their contribution to the activity of the crude extract. The extract as well as the isolated compounds protected red blood cells from hemolysis. This effect was related to a catalase-like activity. This study could contribute to the knowledge of the antioxidant activity of I. paraguariensis in view of the great quantities of yerba maté consumed by the population.