On the characteristics of natural hydraulic dampers: An image-based approach to study the fluid flow behaviour inside the human meniscal tissue.

The meniscal tissue is a layered material with varying properties influenced by collagen content and arrangement. Understanding the relationship between structure and properties is crucial for disease management, treatment development, and biomaterial design. The internal layer of the meniscus is softer and more deformable than the outer layers, thanks to interconnected collagen channels that guide fluid flow. To investigate these relationships, we propose an integrated approach that combines Computational Fluid Dynamics (CFD) with Image Analysis (CFD-IA). We analyze fluid flow in the internal architecture of the human meniscus across a range of inlet velocities (0.1 mm/s to 1.6 m/s) using high-resolution 3D micro-computed tomography scans. Statistical correlations are observed between architectural parameters (tortuosity, connectivity, porosity, pore size) and fluid flow parameters (Re number distribution, permeability). Some channels exhibit Re values of 1400 at an inlet velocity of 1.6 m/s, and a transition from Darcy's regime to a non-Darcian regime occurs around an inlet velocity of 0.02 m/s. Location-dependent permeability ranges from 20-32 Darcy. Regression modelling reveals a strong correlation between fluid velocity and tortuosity at high inlet velocities, as well as with channel diameter at low inlet velocities. At higher inlet velocities, flow paths deviate more from the preferential direction, resulting in a decrease in the concentration parameter by an average of 0.4. This research provides valuable insights into the fluid flow behaviour within the meniscus and its structural influences. 3D models and image stack are available to download at https://doi.org/10.5281/zenodo.10401592. STATEMENT OF SIGNIFICANCE: The meniscus is a highly porous soft tissue with remarkable properties of load transfer and energy absorption. We give insight on the mechanism of energy absorption from high resolution uCT scans, never presented before, and a new method which combine CFD and image. The structure is similar to a sandwich structure with a stiff outside layer and a soft internal layer made of collagen channels oriented in a preferential direction guiding the fluid flow, enabling it to accommodate deformation and dissipate energy, making it a potentially optimized damping system. We investigate architectural/ fluid flow parameters- fluid regimes relationship, which is of interest of the readers working on designing suitable biomimetic systems that can be adopted for replacement.

On the fractional transversely isotropic functionally graded nature of soft biological tissues: Application to the meniscal tissue.

This paper focuses on the origin of the poroelastic anisotropic behaviour of the meniscal tissue and its spatially varying properties. We present confined compression creep test results on samples extracted from three parts of the tissue (Central body, Anterior horn and Posterior horn) in three orientations (Circumferential, Radial and Vertical). We show that a poroelastic model in which the fluid flow evolution is ruled by non-integer order operators (fractional Darcy's law) provides accurate agreement with the experimental creep data. The model is validated against two additional sets of experimental data: stress relaxation and fluid loss during the consolidation process measured as weight reduction. Results show that the meniscus can be considered as a transversely isotropic poroelastic material. This behaviour is due to the fluid flow rate being about three times higher in the circumferential direction than in the radial and vertical directions in the body region of the meniscus. The 3D fractional poroelastic model is implemented in the finite element software to estimate the weight loss during the confined compression tests.

The Functionally Grading Elastic and Viscoelastic Properties of the Body Region of the Knee Meniscus.

The knee meniscus is a highly porous structure which exhibits a grading architecture through the depth of the tissue. The superficial layers on both femoral and tibial sides are constituted by a fine mesh of randomly distributed collagen fibers while the internal layer is constituted by a network of collagen channels of a mean size of 22.14 [Formula: see text]m aligned at a [Formula: see text] inclination with respect to the vertical. Horizontal dog-bone samples extracted from different depths of the tissue were mechanically tested in uniaxial tension to examine the variation of elastic and viscoelastic properties across the meniscus. The tests show that a random alignment of the collagen fibers in the superficial layers leads to stiffer mechanical responses (E = 105 and 189 MPa) in comparison to the internal regions (E = 34 MPa). All regions exhibit two modes of relaxation at a constant strain ([Formula: see text] to 7.7 s, [Formula: see text] = 49.9 to 59.7 s).

High Resolution Micro-Computed Tomography Reveals a Network of Collagen Channels in the Body Region of the Knee Meniscus.

The meniscus is an integral part of the human knee, preventing joint degradation by distributing load from the femoral condyles to the tibial plateau. Recent qualitative studies suggested that the meniscus is constituted by an intricate net of collagen channels inside which the fluid flows during loading. The aim of this study is to describe in detail the structure in which this fluid flows by quantifying the orientation and morphology of the collagen channels of the meniscal tissue. A 7 mm cylindrical sample, extracted vertically from the central part of a lateral porcine meniscus was freeze-dried and scanned using the highest-to-date resolution Microscopic Computed Tomography. The orientation of the collagen channels, their size and distribution was calculated. Comparisons with confocal multi-photon microscopy imaging performed on portions of fresh tissue have shown that the freeze-dried procedure adopted here ensures that the native architecture of the tissue is maintained. Sections of the probe at different heights were examined to determine differences in composition and structure along the sample from the superficial to the internal layers. Results reveal a different arrangement of the collagen channels in the superficial layers with respect to the internal layers with the internal layers showing a more ordered structure of the channels oriented at 30[Formula: see text] with respect to the vertical, a porosity of 66.28% and the mean size of the channels of 22.14 [Formula: see text].

Modified Atmosphere Does Not Reduce the Efficacy of Phytosanitary Irradiation Doses Recommended for Tephritid Fruit Flies.

Phytosanitary irradiation (PI) has been successfully used to disinfest fresh commodities and facilitate international agricultural trade. Critical aspects that may reduce PI efficacy must be considered to ensure the consistency and effectiveness of approved treatment schedules. One factor that can potentially reduce PI efficacy is irradiation under low oxygen conditions. This factor is particularly important because storage and packaging of horticultural commodities under low oxygen levels constitute practices widely used to preserve their quality and extend their shelf life. Hence, international organizations and regulatory agencies have considered the uncertainties regarding the efficacy of PI doses for insects infesting fresh commodities stored under low oxygen levels as a rationale for restricting PI application under modified atmosphere. Our research examines the extent to which low oxygen treatments can reduce the efficacy of phytosanitary irradiation for tephritids naturally infesting fruits. The effects of normoxia (21% O2), hypoxia (~5% O2), and severe hypoxia (< 0.5% O2) on radiation sensitivity of third instars of Anastrepha fraterculus (sensu lato), A. ludens (Loew), Bactrocera dorsalis (Hendel), and Ceratitis capitata (Wiedemann) were evaluated and compared at several gamma radiation doses. Our findings suggest that, compared to normoxia, hypoxic and severe-hypoxic conditioning before and during irradiation can increase adult emergence and contribute to advancement of larval development of tephritid fruit flies only at low radiation doses that are not used as phytosanitary treatments. With phytosanitary irradiation doses approved internationally for several tephritids, low oxygen treatments applied before and during irradiation did not increase the emergence rates of any fruit fly species evaluated, and all treated insects died as coarctate larvae. Thus, the findings of our research support a re-evaluation of restrictions related to phytosanitary irradiation application under modified atmospheres targeting tephritid fruit flies.

Interaction Between Beauveria bassiana (Hypocreales: Cordycipitaceae) and Coptera haywardi (Hymenoptera: Diapriidae) for the Management of Anastrepha obliqua (Diptera: Tephritidae).

The interaction between the entomopathogenic fungus Beauveria bassiana (Balsamo) and the parasitoid Coptera haywardi (Oglobin), as potential biological control agents for Anastrepha obliqua (Macquart) fruit flies, was evaluated under laboratory and semi-protected field cage conditions. The effects of the parasitoids and fungus were individually and jointly assessed in Plexiglas cages. Application of B. bassiana dry conidia to soil produced 40% mortality in A. obliqua adults. However, mortality was lower (21.2%) on evaluation under field cage conditions. According to the multiple decrement life table analysis, the probability of death of A. obliqua was 88% when C. haywardi parasitoids and B. bassiana conidia were used in conjunction, 89% when only C. haywardi parasitoids were released and 23% when only B. bassiana conidia were applied. These results demonstrate that no synergistic, additive or antagonistic interaction took place with the simultaneous use of these natural enemies, since the presence of B. bassiana had no effect on the C. haywardi parasitism. These results indicate that the parasitoid is a better natural enemy for the control of A. obliqua, and show that, although the two biological control agents can be used simultaneously, their joint application will not produce increased control.

Does Beauveria bassiana (Hypocreales: Cordycipitaceae) Affect the Survival and Fecundity of the Parasitoid Coptera haywardi (Hymenoptera: Diapriidae)?

The effect of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin on the development of immature stages, and survival and fecundity of Coptera haywardi (Oglobin) adults was studied under laboratory conditions. The fungus was applied as dry conidia on parasitized pupae of Anastrepha obliqua (Macquart) (Diptera: Tephritidae) and on parasitoid adults of two different age groups (1- to 4-d-old, and 5- to 10-d-old). The fungus caused no negative effects on the development of the immature stages, since there were no differences on the emergence of adults compared with the untreated control. Adults were susceptible to the fungus on both sexes and age groups. Males showed shorter lifespan than females, even in untreated individuals. Despite the increased adult mortality produced by the fungus there was no effect on fecundity during first 18 d of adult life, as the net fecundity was 26.7 and 26.3 parasitoids per female treated and untreated, respectively. Our results suggest that, given the low susceptibility of parasitized pupae and the no effect on fecundity during the first 18 d of adult life, it is possible to develop management strategies using these two natural enemies in the biological control against A. obliqua.

[Oral anaphylaxis by ingestion of mites contaminated oats in Panama City]. / Anafilaxia oral por ingestión de avena contaminada por ácaros en la ciudad de Panamá.

BACKGROUND: Oral anaphylaxis due to food intake contaminated with mites (OMA, oral mite anaphylaxis) is an allergic reaction that can represent life risk for patients. There are reports of cases from different parts of the world and they involve mainly processed foods based on wheat flour contaminated with mites of several families of the Astigmatina cohort. However, it remains as a little known and difficult to diagnose syndrome. The objective of this study was to describe the first clinical case of OMA due to the consumption of oat flakes in Panama City, Panama. CLINICAL CASE: Female patient of 39-years-old was entered an emergency room with allergic cutaneous and respiratory symptoms one hour after ingesting granola and oatmeal with milk at breakfast. After antiallergic treatment, the cause of allergy was determined by applying skin prick tests for ingested food and house mites. Results indicated a negative reaction for food and positive for mites. The mite analysis of the food samples directed in the identification of the species Blattisocius keegani and Suidasia pontifica, with a high density of the latter in flaked oats. CONCLUSION: This work is the first worldwide report of anaphylaxis due to consumption of oats contaminated with mites.

Antecedentes: La anafilaxia oral por ingesta de alimentos contaminados con ácaros (OMA) es una reacción alérgica que puede representar riesgo de vida para los pacientes. Aun cuando se tienen reportes de casos de diversas partes del mundo que involucran principalmente alimentos elaborados con harina de trigo contaminada con ácaros de varias familias de la cohorte Astigmatina, OMA permanece como un síndrome poco conocido y de difícil diagnóstico. El objetivo del estudio fue describir el primer caso de OMA por consumo de avena en hojuelas ocurrido en la ciudad de Panamá, Panamá. Caso clínico: Mujer de 39 años que ingresó a urgencias de un hospital con cuadro alérgico cutáneo y respiratorio una hora después de ingerir granola y avena con leche en el desayuno. Después del tratamiento antialérgico se procedió a determinar la causa de la alergia mediante aplicación de pruebas de punción cutánea para los alimentos ingeridos y ácaros domésticos. Los resultados indicaron reacción negativa para alimentos y positiva para ácaros. El análisis acarológico de las muestras de alimentos resultaron en la identificación de las especies Blattisocius keegani y Suidasia pontifica, con alta densidad de la última en la muestra de avena. Conclusiones: El presente reporte constituye el primero en el mundo de anafilaxia por consumo de avena contaminada con ácaros.

[Oral anaphylaxis by ingestion of mite contaminated food in Panama City, 2011-2014]. / Anafilaxia oral por ingestión de alimentos contaminados con ácaros en Ciudad de Panamá, 2011-2014.

BACKGROUND: Oral mite anaphylaxis (OMA), or pancake syndrome, occurs in atopic individuals when eating starchy foods contaminated by mites, which induce moderate or severe, even fatal, allergic reactions. This syndrome is usually seen in tropical and subtropical environments,where conditions for the growth of domestic mites are given. Oral mite anaphylaxis has been associated with hypersensitivity to acetylsalicylic acid (ASA)-non-steroidal anti-inflammatory drugs (NSAID) and physical exercise. OBJECTIVE: To document the clinical and descriptive study of cases of OMA attended in City of Panama from 2011 to 2014. MATERIAL AND METHOD: A clinical descriptive and retrospective study was performed, including skin prick test to five species of domestic mites. Taxonomic identification of the mites was performed under microscope and its density per gram of food was calculated for three cases. RESULTS: Ten cases with clinical history compatible with OMA were studied, being the pancakes the most incriminated food. The onset of symptoms occurred between 25 and 60 minutes after ingestion of the food. All patients were atopic young adults. Four of the ten patients had hypersensitivity to ASA-NSAID. The patients were positive to Prick test mites: Blomia tropicalis, Dermatophagoides pteronyssinus and Suidasia pontifica. The three samples of wheat flour studied presented high densities of mites per gram. CONCLUSIONS: The pancakes were the most incriminated food in the cases of OMA in our study. Suidasia pontifica and Blomia tropicalis seem to be the mites species of greater relevance related with this syndrome in our country.

Antecedentes: la anafilaxia oral por ácaros, o síndrome de las panquecas, ocurre cuando individuos atópicos ingieren alimentos elaborados con harina de trigo contaminada con ácaros, lo que induce reacciones alérgicas moderadas o severas, incluso fatales. Los reportes provienen de ambientes tropicales y subtropicales, donde las condiciones para la proliferación de ácaros domésticos son favorables. Se ha encontrado una asociación importante con la hipersensibilidad a ácido acetilsalicílico (AAS)-antiinflamatorios no esteroides (AINES) y el ejercicio físico. Objetivo: documentar el estudio clínico y descriptivo de casos de anafilaxia oral por ácaros atendidos en Ciudad de Panamá durante los años 2011 a 2014. Material y método: estudio clínico descriptivo y retrospectivo, que incluyó pruebas cutáneas de punción para cinco especies de ácaros domésticos. La identificación taxonómica de los ácaros se realizó bajo microscopio y se calculó la densidad de ácaros por gramo de alimento en tres casos. Resultados: se estudiaron 10 casos compatibles con anafilaxia oral por ácaros, la panqueca fue el alimento implicado con más frecuencia. Los primeros síntomas aparecieron entre 25 y 60 minutos después de la ingestión del alimento. Todos los pacientes fueron adultos jóvenes atópicos, cuatro con hipersensibilidad a AAS-AINES. Los pacientes resultaron positivos a las pruebas cutáneas de punción para los ácaros: Blomia tropicalis, Dermatophagoides pteronyssinus y Suidasia pontifica. Tres muestras de harina de trigo estudiadas motraron altas densidades de ácaros. Conclusiones: la panqueca fue el alimento implicado con más frecuencia en los casos de anafilaxia oral por ácaros. Suidasia pontifica y Blomia tropicalis parecen ser los ácaros más importantes relacionados con este síndrome en nuestro país.

On high-cycle fatigue of 316L stents.

This paper deals with fatigue life prediction of 316L stainless steel cardiac stents. Stents are biomedical devices used to reopen narrowed vessels. Fatigue life is dominated by the cyclic loading due to the systolic and diastolic pressure and the design against premature mechanical failure is of extreme importance. Here, a life assessment approach based on the Dang Van high cycle fatigue criterion and on finite element analysis is applied to explore the fatigue reliability of 316L stents subjected to multiaxial fatigue loading. A finite element analysis of the stent vessel subjected to cyclic pressure is performed to carry out fluctuating stresses and strain at some critical elements of the stent where cracks or complete fracture may occur. The obtained results show that the loading path of the analysed stent subjected to a pulsatile load pressure is located in the safe region concerning infinite lifetime.

Avances en el tratamiento kinésico del linfedema secundario en pacientes con cáncer de mama / Progress in Kinesic treatment of secondary lymphedema in patients with breast cancer

En el tratamiento del cáncer de mama, la complicación más frecuente que se presenta es el linfedema secundario del miembro superior. El linfedema es una enfermedad crónica provocada por una destrucción de la anatomía linfática normal. Aparece en un 20% -25% de los casos y hasta un 35% cuando la cirugía se asocia a radioterapia. Pese a los importantes avances existentes en el tratamiento de linfedema, no hay un consenso entre los investigadores respecto a la elección de la terapia adecuada, debido a la falta de criterios uniformes de diagnósticos, que se traducen en la derivación tardía de los pacientes hacia los profesionales especializados. El enfoque terapéutico actual consiste en la integración de equipos multidisciplinarios reunidos en un Programa Integral de Rehabilitación del Edema (PIR), el que reúne enfoques preventivos - a través de la educación del paciente - y conservadores tales como el Drenaje Linfático Manual, presoterapia secuencial intermitente, ejercicios específicos, vendaje multicapas y elementos de contención. Estos tratamientos si bien no buscan la cura del Linfedema, permiten minimizar las secuelas funcionales y mejorar la calidad de vida de las pacientes portadoras de esta patología.

In breast cancer treatment, the most common complication is the Secondary Lymphedema of the upper limb. Lymphedema is a chronic disease caused by the destruction of the normal lymphatic anatomy. It is produced in a 20-25% of the cases, and up to 35% when the surgery is associated to radiotherapy. Despite the important existing advances in the management of Iymphedema, there is no consensus between the investigators with respect to the election of the suitable therapy, due to the lack of uniform criteria of diagnosis, which are translated in a delayed derivation of the patients towards the specialized professionals. The present therapeutic approach, consists of the integration of multidisciplinary teams joined in an Integral Program of Rehabilitation of Edema (IPR), which gathers preventive approaches - through the education of the patient - and conservative approaches, such as the MDL (Manual Lymphatic Drainage), Intermittent Sequential Pressotherapy specific. Exercises, multi layer Bandage, and elements of containment. These treatments, although do not aim at the cure of the Lymphedema, allow the decrease of the functional sequels and improve the quality of life of the patients who carry this pathology.