Development of an empirical wall-friction model for 2D simulations of pseudo-2D bubbling fluidized beds

Pseudo-2D fluidized beds have been crucial for the understanding of the dynamics of gas-particle systems. In these systems the distance between the front and back walls is narrow, which restricts and creates a resistance to the solids motion, leading to a different flow behaviour compared to fully 3D systems. This interaction of the particle motion with the walls can be significant and should not be neglected in numerical simulations. The present work develops a new model to easily account for the friction effect between the walls and the particles in a pseudo-2D bed. The model is based on experimental results combined with simplifications of the shear force on a wall provided by the kinetic theory of granular flows. The dependence on the particle diameter and bed thickness is directly introduced in the model through the use of a straightforward expression that is easy to code and does not lead to numerical divergence. To test the model two beds of different thickness were simulated, and the resulting time-averaged solids concentration and velocity as well as bubble properties were compared with experiments. It is shown that the numerical results with the new wall-friction model improve the prediction of the standard 2D-simulations

Is cannulated-screw fixation an alternative to plate osteosynthesis in open book fractures? A biomechanical analysis

Objectives: The current biomechanical work compares the symphyseal and sacroiliac stability obtained with two systems of bone osteosynthesis. The two methods of fixation compared were the 6-hole suprapubic non-locked plate and pubic fixation with two cannulated screws, a novel technique that can be applied percutaneously in the clinical practice. The aim of this study was to examine the validity of the use of two-cannulated-screws osteosynthesis in order to minimize the secondary effects of open fixation, especially in patients in whom an open reduction is contraindicated. Materials and methods: A biomechanical study was designed in 9 fresh, human pelvis specimens, simulating an AO B1.1 type injury, using both fixation systems sequentially in each specimen. In both parts of the test, the specimens were subjected to an axial load of 300N. Displacements and rotations between the different pelvic elements were studied by means of a discrete set of points. The absence of differences between the two systems has been set as the null hypothesis. Results: There were significant differences in favor of the cross-cannulated screws in most of the displacements measured at the pubic symphysis and sacroiliac joint. Conclusions: Fixation of the AO B1.1 type fractures with cross cannulated screws restores the biomechanical behavior of the pubic symphysis, obtaining better stability than fixation with the 6-hole non-locked plate. To date, no comparative, biomechanical studies have been conducted with these two systems of osteosynthesis. This study demonstrates that cross-cannulated screws fixation of the pubic symphysis in AO B1.1 pelvic fractures should be considered as an alternative to the conventional plating system

A questionnaire-based survey in Spain provides relevant information to improve the control of ovine coccidiosis

Ovine coccidiosis is a widespread intestinal parasitic disease caused by Eimeria spp. Lambs are infected by the ingestion of sporulated oocysts, experiencing diarrhea and low growth rates. Control should be based on measures to reduce infection pressure and stress on the animals as well as on appropriate diagnosis and strategic treatment. To obtain information on how control measures are implemented in the ovine sector in Spain, a questionnaire-based survey was completed in 2022 by 154 veterinarians and 173 farmers working in this sector. Coccidiosis was highlighted as a relevant disease by 34% of the respondents. The period of greatest risk seemed to differ between production systems, being mainly early after weaning (7–15 days after weaning) in meat flocks and feedlots and later (1–2 months after weaning) in dairy flocks. The absence of cleaning and disinfection measures was identified as a risk factor by 51% of the veterinarians, with 22% mentioning overcrowding of animals and 22% indicating that coccidiosis has more incidence in flocks with large number of animals. The use of laboratory diagnosis methods (fecal oocyst count) was unusual in 70 and 84% of the veterinarians and farmers, respectively. Regarding control, dairy flocks usually housed a larger number of animals under intensive conditions, and they implemented more frequently control measures for coccidiosis than meat flocks. Anticoccidial drugs were used in 79% of the flocks, and in 74–82% of them, they were applied based on clinical criteria. Comparing protocols for anticoccidial treatment among different production systems, in meat flocks, anticoccidial drugs were applied more frequently when clinical signs were observed, and coccidiostats were used for less than 28 days compared to dairy flocks. These results highlight the need for improvement in the use of anticoccidial treatments adjusted to the new regulatory framework in the EU, which in turn will rationalize the use of antimicrobial compounds and may help to mitigate the impact of coccidiosis in flocks

Dispositivo de anclaje para fijación de pelvis

Dispositivo de anclaje para fijación de pelvis. Permite fijar de forma vertical, segura y estable una pelvis (4) humana en una máquina universal de ensayos (1) de las comprendidas por una mordaza superior (2), una mordaza inferior (3), pudiendo presentar asimismo una célula de carga (6) mediante las cuales es posible medir diferentes parámetros y generar desplazamientos al aplicar cargas axiales sobre la pelvis (4), constituyendo un modelo reproducible y preciso sobre el cual poder realizar futuros estudios y proyectos de investigación biomecánicos sobre pelvis (4), comprendiendo: un anclaje superior (10), vinculado a la célula de carga (6) o a la mordaza superior (2) de la máquina de ensayos (1), destinado a fijar de forma estable la zona superior de la pelvis (4); y un anclaje inferior (30), vinculado a la mordaza inferior (3), destinado a la fijación de unos elementos de apoyo pélvico inferior (5), preferentemente dos huesos fémures, vinculados inferiormente a la pelvis (4).Españ

Dispositivo guía para tratamiento de enfermedades óseas

La presente invención hace referencia a un dispositivo destinado para su uso como guía en el tratamiento de pacientes de enfermedades óseas mediante cirugía percutánea (realizado a través de la piel mediante, por ejemplo, una aguja o una broce), asistido dicho tratamiento por uno o más sistemas de imagen médica. El dispositivo comprende un medio de sujeción de una extremidad del paciente tratado y un medio de posicionamiento configurado para actuar como guía del medio de tratamiento empleado por el cirujano, para la aplicación de dicho medio de tratamiento a una región de la extremidad tratada, donde el medio de posicionamiento comprende una o más plantillas perforadas con una pluralidad de agujeros practicados a lo largo de su superficie destinados a alojar y posicionar el medio de tratamiento.Españ

Percutaneous iliosacral fixation in external rotational pelvic fractures. A biomechanical analysis

Although the gold standard in open book pelvic fractures remains the pubic symphysis (PS) plate fixation, the clinical outcomes are not satisfactory, despite the excellent anatomical reduction assessed radiologically. Some authors suggest that residual instability of the posterior pelvic elements may be responsible for the chronic pain and the early osteoarthritic changes in the sacroiliac joint (SIJ). Objective To evaluate whether the isolated posterior fixation with one or two iliosacral screws (ISSs) is sufficient to provide adequate stability for the treatment of Burgess Young APC-II (YB APC-II) type of pelvic ring injuries. Methods: Biomechanical experimental study using 7 fresh human pelvises, where an YB APC-II pelvic injury was previously implemented. The isolated posterior fixation of the pelvic ring with 1 or 2 ISSs directed in the S1 vertebra body was analysed in each specimen following an axial load of 300 N. The different displacement of the SIJ and of the PS were analysed in all three spatial axes, using the validated optical measurement system 3D PONTOS 5 M. A multivariate version of Friedman test (non-parametric ANOVA for repeated measures) was performed. Results: The isolated fixation of the SIJ with 1 ISS did not show any differences with respect to the intact pelvis (p = 0.851). Regarding the PS, both type of fixations (with 1 or 2 ISSs) confirmed an acceptable correction and adequate control of the PS even though with some differences compared to the intact pelvis (p = 0.01). The presence of the second ISS found not to offer any significant additional benefit. The three-dimensional analysis of the behaviour of the pelvic elements, in these two different types of fixation, did not show any statistical significant differences (p = 0.645). Conclusion: The posterior fixation with ISS can represent an alternative option for treatment of pelvic injuries associated with rotational instability. Further prospective clinical studies are necessary to determine, the influence of the residual pubic symphysis mobility in the every day life, when the above-mentioned technique is applied

Prevention of road crashes in older adults: perspectives on facilitators, barriers and the role of the family doctor

This work was supported by the SEMERGEN-UGR Chair of Teaching and Research in Family Medicine (Catedra de Docencia e Investigacion en Medicina de Familia SEMERGEN-UGR), University of Granada, Spain.Background: People over 64 years have a high fatality rate when they are involved in traffic accidents. Besides, older victims of road crashes are expected to rise in the future due to population aging. The purpose of the study was to document their perception on the role of the family doctor, the main facilitating factors, and the perceived barriers to the temporary or permanent restriction of their driving. Methods: This qualitative study used focus group methodology. A sample of 16 people over 65 years old was obtained through a series of segmentation criteria at an active participation centre for older adults in a small town in Jaén province (Spain). All were invited to participate in a discussion during which they were asked to express their opinions and subjective experiences concerning the role of their family doctor. The group conversation was taped, fully transcribed and analysed, and codes were generated with both deductive and inductive methods. Results: After merging the codes to generate themes, we identified 9 relevant categories: perception of age-related risk, road safety, role of public authorities, driver assessment centre, role of the family doctor, role of the family, proposals for addressing traffic accidents in older adults, consequences of the driving prohibition, and public transport. All categories help to explain the subjective driving and traffic safety experiences of older road users. Conclusions: Although family doctors do not usually ask their older patients about road driving, they are highly valued by these patients. Thus, family doctors have a great potential to act, along with the family members, for the benefit of older patients’ traffic safety, in ways that can prevent their involvement in road crashes and reduce the negative consequences of having to stop driving if necessary.SEMERGEN-UGR Chair of Teaching and Research in Family Medicine (Catedra de Docencia e Investigacion en Medicina de Familia SEMERGEN-UGR), University of Granada, Spai

Trochoidal Milling Path with Variable Feed. Application to the Machining of a Ti-6Al-4V Part

Trochoidal milling is a well-stablished machining strategy which still allows for the introduction of new approaches. This strategy can be applied to any kind of material, although it is usually associated to advanced materials, such as titanium and nickel alloys. This study is based on the adaptation of the feed speed of a milling tool with Ti-6Al-4V, so the chip width can be maintained constant without modifying the path geometry. A singularity in the experimental stage was to mill an Archimedes spiral groove instead of the conventional straight grooves. This made it possible to obtain a concave wall as well as a convex one and to optimize the amount of material used. The time efficiency compared to a constant feed, was slightly superior to 20%, reducing tool wear also. These techniques require milling machines with high mechanical and kinematic performance, as well as the absence of clearance between joints and a high acceleration capacity

MKP1 mediates chemosensitizer effects of E1a in response to cisplatin in non-small cell lung carcinoma cells

The adenoviral gene E1a is known to enhance the antitumor effect of cisplatin, one of the cornerstones of the current cancer chemotherapy. Here we study the molecular basis of E1a mediated sensitivity to cisplatin in an experimental model of Non-small cell lung cancer. Our data show how E1a blocks the induction of autophagy triggered by cisplatin and promotes the apoptotic response in resistant cells. Interestingly, at the molecular level, we present evidences showing how the phosphatase MKP1 is a major determinant of cisplatin sensitivity and its upregulation is strictly required for the induction of chemosensitivity mediated by E1a. Indeed, E1a is almost unable to promote sensitivity in H460, in which the high expression of MKP1 remains unaffected by E1a. However, in resistant cell as H1299, H23 or H661, which display low levels of MKP1, E1a expression promotes a dramatic increase in the amount of MKP1 correlating with cisplatin sensitivity. Furthermore, effective knock down of MKP1 in H1299 E1a expressing cells restores resistance to a similar extent than parental cells. stores resistance to a similar extent than parental cells. In summary, the present work reinforce the critical role of MKP1 in the cellular response to cisplatin highlighting the importance of this phosphatase in future gene therapy approach based on E1a gene

ERK5/BMK1 is a novel target of the tumor suppressor VHL: implication in clear cell renal carcinoma

Hi ha quatre pàgines de material suplementari sense numeracióExtracellular signal-regulated kinase 5 (ERK5), also known as big mitogen-activated protein kinase (MAPK) 1, is implicated in a wide range of biologic processes, which include proliferation or vascularization. Here, we show that ERK5 is degraded through the ubiquitin-proteasome system, in a process mediated by the tumor suppressor von Hippel-Lindau (VHL) gene, through a prolyl hydroxylation-dependent mechanism. Our conclusions derive from transient transfection assays in Cos7 cells, as well as the study of endogenous ERK5 in different experimental systems such as MCF7, HMEC, or Caki-2 cell lines. In fact, the specific knockdown of ERK5 in pVHL-negative cell lines promotes a decrease in proliferation and migration, supporting the role of this MAPK in cellular transformation. Furthermore, in a short series of fresh samples from human clear cell renal cell carcinoma, high levels of ERK5 correlate with more aggressive and metastatic stages of the disease. Therefore, our results provide new biochemical data suggesting that ERK5 is a novel target of the tumor suppressor VHL, opening a new field of research on the role of ERK5 in renal carcinomas