Viability Of Implants Research Articles

Review of Bus Differential Protection Using IEC 61850

The electrical power system is susceptible to several faults, which can cause the system to malfunction. Among these, the ones that occur in the busbars of substations stand out. The main bus of a substation can concentrate a large amount of power and many derivations to service electrical loads, making it an element of high importance for the reliability of the system. Although the buses have a low incidence of faults, they are considered critical elements of the electrical power system, as their operating output can cause a large number of forced outages. This situation makes the protection of this component of paramount importance. There are currently two widely used bus differential protection techniques: high-impedance and low-impedance bus differential protection. The second technique is more commonly used due to the possibility of sharing current transformers (CTs). However, the high cost and greater requirements for maintenance makes the differential protection of busbars in distribution or sub-transmission substations unfeasible. With the advent and implementation of the IEC 61850 standard, modern protection systems based on this standard offer significant advantages, such as lower expenses with installation, wiring, commissioning and maintenance; adaptable bus configuration; use of different CT ratios; considerably minimized susceptibility to CT saturation; lower risks of open secondary CT circuits and viability of implantation in distribution substations. The objective of this review is to present an overview of the works found in the literature on substation busbar differential protection, considering classical methods and those based on the IEC 61850 standard.

Breast implant imaging by ultrasound and MRI (Magnetic Resonance imaging)

This proportion of females who get breast augmentation is rapidly expanding. Like a result, a radiologist's knowledge of the typical or aberrant radiological presentations of prevalent breast implants is critical. Mammography, Ultrasonography, or MRI are used to assess implant durability, identify disorders of the device as well as its accompanying capsules, and diagnose mammary diseases unconnected to implantation. Through its great accuracy or precision for identifying implant disintegration, magnetic resonance imaging of silicone breast augmentation is the best trustworthy method for determining prosthetic health. An ultimate goal of scanning breast implants, regardless of the computed tomography utilized, is to offer meaningful information regarding implantation viability, identify implantation malfunctions, or diagnose breast diseases unconnected to the augmentations, like cancers.

WEDM microdrilling of 316 L stainless steel orthopedic implant

The development in manufacturing has insisted upon the fabrication of microdrilled holes on orthopedic implants, with finished side wall (devoid of cracks and burr), thin recast layer, low taper, and improved circularity at entry and exit of the hole. In this study, therefore, a multiobjective optimization of wire electric discharge machining microdrilling response characteristics is addressed in order to improve the hole quality characteristics and viability of implants. To improve the quality characteristics of the hole, a hybrid statistical analysis is developed based on grey relational analysis and coefficient of variation. It identifies the key process parameters that are responsible for improving the quality of the hole. The parametric study also reveals that wire feed rate and servo feed rate have a striking effect on the quality of the hole. An important implication of this study is that a thin recast layer, improved entry and exit circularity, adequate taper were observed under optimum drilling condition.

β-Caryophyllene causes regression of endometrial implants in a rat model of endometriosis without affecting fertility

Many studies have shown that anti-inflammatory agents are effective in the treatment of endometriosis. β-Caryophyllene exerted a potent anti-inflammatory effect in vivo. However, its effect on endometriosis has not been investigated. This study aims at investigating the effect of β-caryophyllene on endometriosis and on fertility and reproduction in adult female rats. Autologous fragments of the endometrium were implantated in the peritoneal cavity in adult female rats. The growth of the endometriotic implants that developed after four weeks was recorded. Treatment started then with β-caryophyllene (10mg/kg or 30mg/kg) or vehicle (control) for 21 days and the growth of the endometriotic implants was measured again. In fertility studies, female rats that received β-caryophyllene or vehicle were mated and reproductive functions were observed including number and viability of implants, number of corpora lutea, length of pregnancy and outcome of litter. β-Caryophyllene (10mg/kg) suppressed the growth of endometriotic implants by 52.5% compared with controls. Also β-caryophyllene produced apoptosis in luminal epithelim of the cyst as well as in endothelial cells of blood vessels. Ultrstructural studies revealed the presence of active mast cells and eosinophils in both control and β-caryophyllene-treated rat cysts. No statistically significant difference was observed in any studied parameter between control and β-caryophyllene-treated groups in fertility study. Therapy with β-caryophyllene may present a promising novel, non-toxic therapeutic option for patients with endometriosis.

Surgical Results and Microscopic Analysis of the Tissue Reaction following Implantation and Explantation of an Intraocular Implant for Epiretinal Stimulation in Minipigs

Aims: For the purpose of visual rehabilitation of subjects with photoreceptor degeneration, an implantable microelectronic device for epiretinal stimulation was developed. Our study aimed to show whether implantation and explantation could be conducted safely and to investigate tissue compatibility. Methods: The device was implanted in 5 Göttinger minipigs. Four weeks later, the implant was surgical- ly removed. Histopathological examination that followed aimed at detecting inflammatory or proliferative changes. Stains used were hematoxylin and eosin, leukocyte common antigen, CD68 and glial fibrillary acidic protein. A grinding technique was used to visualize the retinal tissue in conjunction with the retinal tacks. Results: The implantation of the devices was successful in all cases. The explantation was complicated by intraoperative hemorrhages. Complete explantation could only be achieved after modifying the implantation strategy. Histopathology revealed a mild degree of cystic disaggregation of the retina. Immunohistochemically, an increased glial fibrillary acidic protein expression of Müller cells was found, which shows a moderate glial cell activation. Inflammatory cells were absent. Using the grinding technique, tissue adjacent to the retinal tacks showed a mild gliosis. Discussion: The viability of implantation and explantation of the implant in minipigs has been shown. The absence of immunoreactive cells or a considerable glial reaction suggest that the device may be considered safe and suitable for further implantation in humans.

Deformation behavior of medical synthetic monofilaments

Viscoelastic behavior has been examined for polypropylene and polyvinylidene fluoride monofilaments for making reticular endoprostheses. The deformation behavior corresponds to linear viscoelasticity. The parameters have been determined for monofilament creep. A method is proposed for describing the creep, and the strains calculated from it in creep at various stresses agree with the experimental ones. These results serve as basis for forecasting the viability of implants made from these monofilaments.

Viabilidade da implantação de um contrato de comercialização futura da madeira de reflorestamento no Brasil

Este estudo analisou a viabilidade de implantação de um contrato futuro da madeira de Eucalyptus spp. para celulose. Para isso, tomou-se como referência a abordagem micro do modelo de Pennings e Leuthold (1999). Os dados foram coletados por meio de questionários direcionados às empresas de celulose. Os resultados indicaram que os gestores principais das empresas possuem características de indivíduos propensos a negociar em bolsas, como elevado nível de escolaridade e idade abaixo de 60 anos. Além disso, tais resultadosevidenciaram uma provável demanda por contratos futuros de madeira pelas empresas e que estas possuem condições financeiras suficientes para operar em bolsas, estão expostas e são avessas ao risco e que os funcionários de quase todas elas recebem treinamento nas áreas de economia e administração. Portanto, concluiu-se que existe grande potencial para a implantação de um contrato futuro desse tipo de madeira no Brasil.