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1.
Meat Sci ; 186: 108734, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35033833

ABSTRACT

Forty crossbred (Santa Ines × Dorper) male lambs were used to investigate the effect of dietary buriti oil (BOIL) intake on meat quality, fatty acid (FA) composition and sensory attributes. A completely randomized design with five BOIL intake levels (0, 12, 24, 36 and 48 g/kg DM) was used. Increasing dietary BOIL intake linearly reduced the DMI, slaughter weight, cooking loss, shear force, yellowness, 16:0, c9-18:1 FA concentrations, and the delta-9-desaturase activity index computed using c9-16:1 and 16:0 as product and substrate pair, cis-MUFA and Æ©MUFA/Æ©SFA ratio of lamb meat (P ≤ 0.05); however, increasing dietary BOIL intake quadratically increased the energy intake, lipid content and linearly increased the total FA intake, chroma, collagen, total BI, 18:0, 20:3n-6 concentration and sensory attributes of lamb meat (P ≤ 0.05), without affecting health indexes regarding fat consumption. BOIL addition at levels above 24 g/kg DM in lamb diet reduces growth, however, improves tenderness, flavor and "goat" aroma intensity and slightly changes meat FA levels, promoting better acceptance by panelists.


Subject(s)
Dietary Fats, Unsaturated , Red Meat , Animal Feed/analysis , Animals , Carotenoids , Diet/veterinary , Fatty Acids , Male , Meat/analysis , Plant Oils , Red Meat/analysis , Sheep
2.
J Geophys Res Planets ; 126(11): e2021JE006898, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34824965

ABSTRACT

Carbonate minerals have been detected in Jezero crater, an ancient lake basin that is the landing site of the Mars 2020 Perseverance rover, and within the regional olivine-bearing (ROB) unit in the Nili Fossae region surrounding this crater. It has been suggested that some carbonates in the margin fractured unit, a rock unit within Jezero crater, formed in a fluviolacustrine environment, which would be conducive to preservation of biosignatures from paleolake-inhabiting lifeforms. Here, we show that carbonate-bearing rocks within and outside of Jezero crater have the same range of visible-to-near-infrared carbonate absorption strengths, carbonate absorption band positions, thermal inertias, and morphologies. Thicknesses of exposed carbonate-bearing rock cross-sections in Jezero crater are ∼75-90 m thicker than typical ROB unit cross-sections in the Nili Fossae region, but have similar thicknesses to ROB unit exposures in Libya Montes. These similarities in carbonate properties within and outside of Jezero crater is consistent with a shared origin for all of the carbonates in the Nili Fossae region. Carbonate absorption minima positions indicate that both Mg- and more Fe-rich carbonates are present in the Nili Fossae region, consistent with the expected products of olivine carbonation. These estimated carbonate chemistries are similar to those in martian meteorites and the Comanche carbonates investigated by the Spirit rover in Columbia Hills. Our results indicate that hydrothermal alteration is the most likely formation mechanism for non-deltaic carbonates within and outside of Jezero crater.

3.
J Biomech ; 129: 110812, 2021 12 02.
Article in English | MEDLINE | ID: mdl-34688063

ABSTRACT

A cochlear implant is an electronic device implanted into the cochlea to directly stimulate the auditory nerve. Such device is used in patients with severe-to-profound hearing loss. The cochlear implant surgery is safe, but involves some risks, such as infections, device malfunction or damage of the facial nerve and it can result on a poor hearing outcome, due to the destruction of any present residual hearing. Future improvements in cochlear implant surgery will necessarily involve the decrease of the intra-cochlear damage. Several implant related variables, such as materials, geometrical design, processor and surgical techniques can be optimized in order for the patients to partially recover their hearing capacities The straight electrode is a type of cochlear implant that many authors indicate as being the less traumatic. From the finite element analysis conducted in this work, the influence of the insertion speed, the friction coefficient between the cochlear wall and the electrode array, and several configurations of the cochlear implant tip were studied. The numerical simulations of the implantation showed the same pattern of the insertion force against insertion depth, thus indicating the different phases of the insertion. Results demonstrated that lower insertion speeds, friction coefficients and tip stiffness, led to a reduction on the contact pressures and insertion force. It is expected that these improved configurations will allow to preserve the residual hearing while reducing surgical complications.


Subject(s)
Cochlear Implantation , Cochlear Implants , Cochlea/surgery , Finite Element Analysis , Hearing , Humans
4.
Arq. bras. med. vet. zootec. (Online) ; 73(5): 1187-1193, Sept.-Oct. 2021. tab
Article in English | LILACS, VETINDEX | ID: biblio-1345279

ABSTRACT

This research article aims to evaluate the effect of total replacement of corn by soybean meal and urea on intake and apparent digestibility of dry matter and its components, production and composition of milk and feeding behavior of lactating cows grazing, with intermittent stocking Mombaça grass (Megathyrsus maximus cv. Mombaça). Twelve milking cows were distributed in a triple 4 x 4 latin square. Experimental treatments consisted of four soybean meal replacement levels by corn more urea (0; 33; 66; 100%). The grass has an average content of crude protein and neutral detergent fiber of 19% and 59%, respectively. The replacement of soybean meal by corn and urea did not affect the intake and digestibility of nutrients. A linear reduction of milk production was observed, but there was no change in milk production corrected to 4.0% of fat. The milk components (g/kg) of fat, protein, lactose, and total solids were not altered, as well as feeding behavior. Under the conditions of this study, the replacement of the diets is suitable for crossbred dairy cows in lactation third medium, producing in average of 12.5 kg/day-1 when kept in quality pastures.(AU)


Este artigo de pesquisa tem como objetivo avaliar o efeito da substituição total do milho pelo farelo de soja e ureia sobre o consumo e a digestibilidade aparente da matéria seca e de seus componentes, a produção e a composição do leite e o comportamento alimentar de vacas em lactação mantidas em pastos capim-mombaça (Megathyrsus maximus cv. Mombaça) manejado sob lotação intermitente. Doze vacas em lactação foram distribuídas em um quadrado latino triplo 4 x 4. Os tratamentos experimentais consistiram de quatro níveis de substituição do farelo de soja pelo milho mais ureia (0; 33; 66; 100%). O capim-mombaça apresentou um teor médio de proteína bruta e de fibra em detergente neutro de 19% e 59%, respectivamente. A substituição do farelo de soja por milho e ureia não afetou o consumo e a digestibilidade dos nutrientes. Observou-se redução linear da produção de leite, mas não houve alteração na produção de leite corrigida para 4,0% de gordura. Os componentes do leite (g/kg): gordura, proteína, lactose e sólidos totais não foram alterados, assim como o comportamento ingestivo dos animais. Nas condições deste estudo, a substituição total do milho pelo farelo de soja e ureia nas dietas é adequada para vacas mestiças leiteiras em terço médio de lactação, produzindo, em média, 12,5 kg / dia-1 quando mantidas em pastagens de qualidade.(AU)


Subject(s)
Animals , Female , Cattle , Glycine max , Urea , Zea mays , Diet/veterinary , Animal Feed , Milk Proteins/analysis
5.
Tech Coloproctol ; 25(11): 1243-1248, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34499277

ABSTRACT

BACKGROUND: Colon capsule endoscopy (CCE) is a minimally invasive alternative for patients unwilling to undergo conventional colonoscopy, or for whom the latter exam is contraindicated. This is particularly important in the setting of colorectal cancer screening. Nevertheless, these exams produce large numbers of images, and reading them is a monotonous and time-consuming task, with the risk of overlooking important lesions. The development of automated tools based on artificial intelligence (AI) technology may improve some of the drawbacks of this diagnostic instrument. METHODS: A database of CCE images was used for development of a Convolutional Neural Network (CNN) model. This database included anonymized images of patients with protruding lesions in the colon or patients with normal colonic mucosa or with other pathologic findings. A total of 3,387,259 frames from 24 CCE exams were retrospectively reviewed. For CNN development, 3640 images (860 protruding lesions and 2780 with normal mucosa or other findings) were ultimately extracted. Training and validation datasets were constructed for the development and testing of the CNN. RESULTS: The CNN detected protruding lesions with a sensitivity, specificity, positive and negative predictive values of 90.7, 92.6, 79.2 and 96.9%, respectively. The area under the receiver operating characteristic curve for detection of protruding lesions was 0.97. CONCLUSIONS: The deep learning algorithm we developed is capable of accurately detecting protruding lesions. The application of AI technology to CCE may increase its diagnostic accuracy and acceptance for screening of colorectal neoplasia.


Subject(s)
Capsule Endoscopy , Colorectal Neoplasms , Artificial Intelligence , Colon/diagnostic imaging , Colonoscopy , Colorectal Neoplasms/diagnostic imaging , Humans , Retrospective Studies
6.
J Biomech ; 127: 110649, 2021 10 11.
Article in English | MEDLINE | ID: mdl-34375905

ABSTRACT

The female pelvic cavity involves muscles, ligaments, endopelvic fasciae and multiple organs where different pathologies may occur, namely the pelvic organ prolapse (POP). The synthetic implants are used for the reconstructive surgery of POP, but severe complications associated with their use have been reported, mainly related to their mechanical properties (e.g., implant stiffness) and microstructure. In this study, we mimicked a transvaginal reconstructive surgery to repair the apical ligaments (uterosacral ligaments (USLs) and cardinal ligaments (CLs)), by modeling, their impairment (90% and 50%) and/or total rupture. The implants to reinforce/replace these ligaments were built based on literature specifications and their mechanical properties were obtained through uniaxial tensile tests. The main aim of this study was to simulate the effect of mesh anchoring technique (simple stich and continuous stitch), and compare the displacement magnitude of the pelvic tissues, during Valsalva maneuver. The absence/presence of the synthetic implant was simulated when total rupture of the CLs and USLs occurs, causing a variation of the vaginal displacement (9% for the CLs and 27% for the USLs). Additionally, the simulations showed that there was a variation of the supero-inferior displacement of the vaginal wall between different anchoring techniques (simple stich and continuous stitch) being approximately of 10% for the simulation USLs and CLs implant. The computational simulation was able to mimic the biomechanical behavior of the USLs and CLs, in response to different anchoring techniques, which can be help improving the outcomes of the prolapse surgery.


Subject(s)
Pelvic Organ Prolapse , Uterine Prolapse , Female , Finite Element Analysis , Humans , Ligaments/surgery , Pelvic Organ Prolapse/surgery , Surgical Mesh , Treatment Outcome
7.
Ann Biomed Eng ; 49(12): 3593-3608, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34114131

ABSTRACT

Caesarean section is one of the most common surgeries worldwide, even though there is no evidence supporting maternal and perinatal long-term benefits. Furthermore, the mechanical behavior of a caesarean scar during a vaginal birth after caesarean (VBAC) is not well understood since there are several questions regarding the uterine wound healing process. The aim of this study is to investigate the biomechanical Maylard fiber reorientation and stiffness influence during a VBAC through computational methods. A biomechanical model comprising a fetus and a uterus was developed, and a chemical-mechanical constitutive model that triggers uterine contractions was used, where some of the parameters were adjusted to account for the matrix and fiber stiffness increase in the caesarean scar. Several mechanical simulations were performed to analyze different scar fibers arrangements, considering different values for the respective matrix and fibers stiffness. The results revealed that a random fiber arrangement in the Maylard scar has a much higher impact on its mechanical behavior during a VBAC than the common fibers arrangement present in the uninjured uterine tissue. An increase of the matrix scar stiffness exhibits a lower impact, while an increase of the fiber's stiffness has no significant influence.


Subject(s)
Cicatrix/physiopathology , Models, Biological , Uterus/physiology , Vaginal Birth after Cesarean , Biomechanical Phenomena , Female , Humans , Pregnancy , Risk Factors
8.
Animal ; 15(1): 100035, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33516030

ABSTRACT

In cull ewes, energy supply by time short periods can affect growth, carcass traits, and meat quality. The objective of this study was to evaluate the effect of biscuit bran (BB) and cashew nut bran (CNB) in diets with different total digestible nutrient (TDN) content on animal performance and carcass and meat traits of cull ewes. Twenty Morada Nova cull ewes, with the initial BW of 30.1 ±â€¯3.56 kg, and three years of age were distributed in a completely randomized design into factorial scheme 2 × 2, with two energy sources (BB and CNB) × two levels of TDN. All diets were isoproteic with variations in TDN content increased by 10% (TDN10) and 25% (TDN25) above the recommended requirement for the study category, which was 66.0% TDN. The experimental period lasted 56 days, in which daily intake in relation to metabolic weight and weight performance of the animals was determined. The hot carcass, the cold carcass, commercial cuts, loin eye area, and subcutaneous fat thickness were measured, obtained, or calculated. A sample of the Longissimus lumborum (LL) muscle was used by determination of physical-chemical composition, sensory, and fatty acid (FA) profile analysis. The ANOVA was performed to access the effect of diet and energy level on the characteristics studied, and means were compared by the Turkey and Kruskal Wallis tests at 5% of probability. A higher daily gain weight was observed from TDN25 (P = 0.006). Among by-products, higher nutrient intakes were observed in animals fed with BB diets (P < 0.01), except for crude protein. The same patterns have been observed for live weight, reconstituted half-carcass, higher yield in fat thickness, and internal carcass length. Cashew nut bran produced darker colored meat (P = 0.017) and higher cooking weight loss (P = 0.008). Higher lipid content was observed in animals submitted to diets with CNB and TDN25 (P = 0.001). The internal length of the carcass was higher in animals fed with BB (P = 0.041). All diets did not effect on sensory characteristics (P > 0.05). Total digestible nutrient in 25% above recommended promotes higher weight gain and meat with higher lipid content and less weight loss by cooling. The inclusion of BB, compared to CNB, provides a higher weight of carcasses and better conformation, in addition to lower total lipid content with higher proportion for monounsaturated FAs in meat, providing more attractive features for the consumer market.


Subject(s)
Animal Feed , Body Composition , Animal Feed/analysis , Animals , Diet/veterinary , Female , Meat/analysis , Sheep , Turkey
9.
J Mech Behav Biomed Mater ; 110: 103956, 2020 10.
Article in English | MEDLINE | ID: mdl-32957249

ABSTRACT

BACKGROUND: One of the major causes of pelvic organ prolapse is pelvic muscle injury sustained during a vaginal delivery. The most common site of this injury is where the pubovisceral muscle takes origin from the pubic bone. We hypothesized that it is possible for low-cycle material fatigue to occur at the origin of the pubovisceral muscle under the large repetitive loads associated with pushing during the second stage of a difficult labor. PURPOSE: The main goal was to test if the origin of the pubovisceral muscle accumulates material damage under sub-maximal cyclic tensile loading and identify any microscopic evidence of such damage. METHODS: Twenty origins of the ishiococcygeous muscle (homologous to the pubovisceral muscle in women) were dissected from female sheep pelvises. Four specimens were stretched to failure to characterize the failure properties of the specimens. Thirteen specimens were then subjected to relaxation and subsequent fatigue tests, while three specimens remained as untested controls. Histology was performed to check for microscopic damage accumulation. RESULTS: The fatigue stress-time curves showed continuous stress softening, a sign of material damage accumulation. Histology confirmed the presence of accumulated microdamage in the form of kinked muscle fibers and muscle fiber disruption in the areas with higher deformation, namely in the muscle near the musculotendinous junction. CONCLUSIONS: The origin of ovine ishiococcygeous muscle can accumulate damage under sub-maximal repetitive loading. The damage appears in the muscle near the musculotendinous junction and was sufficient to negatively affect the macroscopic mechanical properties of the specimens.


Subject(s)
Pelvic Floor , Pelvic Organ Prolapse , Animals , Delivery, Obstetric , Fatigue , Female , Muscle, Skeletal , Pregnancy , Sheep
10.
Int J Cosmet Sci ; 42(6): 548-556, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32478433

ABSTRACT

OBJECTIVE: The aim of the present study was to evaluate the influence of the incorporation of caffeine as a model active ingredient on the quality attributes of a bioadhesive emulgel formulation previously optimized by Quality by Design (QbD) tools. Emulgels are emerging topical drug delivery systems for cosmetic or pharmaceutical uses, which combine the advantages of both emulsions and gels. METHODS: In this work, the observed and predicted values for spreadability, phase separation by centrifugation and detachment forces performed by texturometer were compared with those of the control and active-containing emulgel formulations. In addition, rheological properties, release of caffeine and comparative in vitro/ex vivo bioadhesion properties were evaluated using human skin. RESULTS: The flow curves of emulgel formulations showed the typical pseudoplastic and no thixotropic flow with yield stress. The incorporation of active ingredient did not produce significant changes. All emulgels were uniformly spread and no significant differences in spreadability values between control and caffeine containing formulations and neither respect to those predicted values from experimental design optimization were found. Emulgel formulations showed appropriate detachment forces values and no significant differences between caffeine loading and control emulgel formulations were observed. CONCLUSION: Caffeine was successfully vehiculized in this optimized bioadhesive emulgel formulation, which showed high robustness regarding the process variability. There were no significant changes in the critical quality attributes after the incorporation of the active ingredient and a promising stability was observed for at least one year. Results suggested that the optimized emulgel is an interesting topical biodhesive delivery system for cosmetic applications, including agents for skin conditioning, not present in gels formulations.


OBJECTIF: la présente étude visait à évaluer l'influence de l'incorporation de la caféine comme une substance active modèle dans les attributs de qualité d'une préparation d'émulgel bioadhésif préalablement optimisée grâce à des outils QbD (Quality by Design, Qualité par la conception). Les émulgels sont des systèmes d'administration de médicaments topiques émergents destinés à des usages cosmétiques ou pharmaceutiques, qui associent les avantages des émulsions et des gels. MÉTHODES: dans cet étude, les valeurs observées et prédites en matière d'étalement, de séparation des phases par centrifugation et de forces de détachement par texturomètre ont été comparées à celles des préparations de contrôle et d'émulgel contenant des actifs. En outre, les propriétés rhéologiques, la libération de caféine et la comparaison des propriétés de bioadhérence in vitro / ex vivo ont été évaluées sur la peau humaine. RÉSULTATS: les courbes de débit des préparations d'émulgel révèlent un flux pseudoplastique typique et non thixotropique avec charge d'écoulement. L'incorporation de la substance active n'a pas produit de changements importants. Tous les émulgels ont été uniformément étalés et aucune différence significative dans les valeurs d'étalement entre les préparations de contrôle et celles contenant de la caféine n'a été observée. Aucune différence concernant les valeurs prédites dans l'optimisation de la conception expérimentale n'a été observée. Les préparations d'émulgel ont montré des valeurs de forces de détachement appropriées et aucune différence significative n'a été observée entre les préparations d'émulgel à base de caféine et les préparations de contrôle. CONCLUSION: la caféine a été administrée avec succès dans cette préparation optimisée d'émulgel bioadhésif, qui a affiché une grande résistance en ce qui concerne la variabilité du procédé. Il n'y a pas eu de changement significatif dans les attributs de qualité critiques après l'incorporation de la substance active et une stabilité prometteuse a été observée pendant au moins un an. Les résultats ont suggéré que l'émulgel optimisé est un système d'administration de bioadhérence topique intéressant pour les applications cosmétiques, y compris les agents de revitalisation de la peau qui ne se trouvent pas dans les préparations de gels.


Subject(s)
Caffeine/chemistry , Cosmetics , Drug Compounding , Drug Design , Gels/chemistry , Tissue Adhesives/chemistry , Humans
11.
Trop Anim Health Prod ; 52(5): 2461-2468, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32350820

ABSTRACT

The use of agricultural by-products might provide an important alternative to improve animal agriculture and to reduce feeding costs. The effects of inclusion in the diet of four levels of delinted cottonseed (0, 80, 160, and 240 g/kg) on intake, digestibility, nitrogen balance, blood parameters, and the ingestive behaviour of confined sheep were studied. Twenty-four mixed-breed rams with an average body weight of 27.6 ± 2.9 kg were used in a completely randomised design with four treatments. The addition of delinted cottonseed (DCS) did not alter (P > 0.05) the intake of dry matter, crude protein, organic matter, neutral detergent fibre, or ether extract in the two forms calculated (g/day and % body weight). The use of different levels of DCS in sheep feed did not influence (P > 0.05) the voluntary water intake. The dietary DCS levels linearly affected (P < 0.05) the digestibility coefficients of the dry matter (DM), organic matter, neutral detergent fibre, ether extract, and non-fibrous carbohydrates. The DCS inclusion levels did not affect the nitrogen balance (P = 0.22), plasma concentrations of urea (P = 0.51), and glucose (P = 0.17).The feeding efficiency and rumination in g DM/h reduced linearly (P < 0.05) with the addition of DCS in the diet. Therefore, the addition of delinted cottonseed affects the intake, digestibility, and ingestive behaviour of confined sheep, and the addition of up to 80 g/kg delinted cottonseed in the diet of confined sheep is recommended.


Subject(s)
Animal Feed/analysis , Diet/veterinary , Gossypium/chemistry , Seeds/chemistry , Sheep , Animal Nutritional Physiological Phenomena , Animals , Body Weight , Dietary Fiber/metabolism , Digestion , Feeding Behavior , Male , Sheep Diseases
12.
Acta Biomater ; 110: 175-187, 2020 07 01.
Article in English | MEDLINE | ID: mdl-32335309

ABSTRACT

The remodeling mechanisms that cause connective tissue of the vaginal wall, consisting mostly of smooth muscle, to weaken after vaginal delivery are not fully understood. Abnormal remodeling after delivery can contribute to development of pelvic organ prolapse and other pelvic floor disorders. The present study used vaginal smooth muscle cells (vSMCs) isolated from knockout mice lacking the expression of the lysyl oxidase-like1 (LOXL1) enzyme, a well-characterized animal model for pelvic organ prolapse. We tested if vaginal smooth muscle cells from LOXL1 knockout mice have altered mechanics including stiffness and surface adhesion. Using atomic force microscopy, we performed nanoindentations on both isolated and confluent cells to evaluate the effect of LOXL1 knockout on in vitro cultures of vSMCs cells from nulliparous mice. The results show that LOXL1 knockout vSMCs have increased stiffness in pre-confluent but decreased stiffness in confluent cultures (p* < 0.05) and significant decreased surface adhesion in pre-confluent cultures (p* < 0.05). This study provides evidence that the weakening of vaginal connective tissue in the absense of LOXL1 changes the mechanical properties of the vSMCs. STATEMENT OF SIGNIFICANCE: Pelvic organ prolapse is a common condition affecting millions of women worldwide, which significantly impacts their quality of life. Alterations in vaginal and pelvic floor mechanical properties can change their ability to support the pelvic organs. This study provides evidence of altered stiffness of vaginal smooth muscle cells from mice resembling pelvic organ prolapse. The results from this study set a foundation to develop pathophysiology-driven therapies focused on the interplay between smooth muscle mechanics and extracellular matrix remodeling.


Subject(s)
Protein-Lysine 6-Oxidase , Quality of Life , Amino Acid Oxidoreductases , Animals , Female , Mice , Myocytes, Smooth Muscle , Protein-Lysine 6-Oxidase/genetics , Vagina
13.
Comput Methods Biomech Biomed Engin ; 23(8): 408-421, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32189515

ABSTRACT

The present study aims to compare spinal stability after two different minimally invasive techniques, the lateral lumbar interbody fusion (LLIF) and the transforaminal lumbar interbody fusion (TLIF) approaches. Two nonlinear three-dimensional finite element (FE) models of the L4-L5 functional spinal unit (FSU) were subjected to the loads that usually act on the lumbar spine. Findings show that the LLIF approach yields better results for torsion load case, due to the larger surface area of the implant. For extension, flexion and lateral bending loads, the TLIF approach presents smaller displacements probably due to the anterior placement of the cage and to the smaller damaged area of the annulus fibrosus.


Subject(s)
Computer Simulation , Lumbar Vertebrae/surgery , Minimally Invasive Surgical Procedures , Numerical Analysis, Computer-Assisted , Spinal Fusion , Biomechanical Phenomena , Cancellous Bone/surgery , Cortical Bone/surgery , Humans , Models, Theoretical , Prostheses and Implants , Reproducibility of Results , Rotation , Stress, Mechanical
14.
Comput Methods Biomech Biomed Engin ; 23(8): 384-395, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32096422

ABSTRACT

This paper presents a finite element analysis to investigate the biomechanical changes caused by transforaminal (TLIF) and anterior lumbar interbody fusion (ALIF) at the L5-S1 level, applying two different implants: T_PAL (TLIF) and SynFix (ALIF). The main objective is to determine which one is more stable for patients. Numerical simulations of segmental motion show that, in the early postoperative phase, displacements and rotation angles obtained in ALIF are greater than the corresponding ones obtained in TLIF, as well as the principal stress values on the ligaments. So, TLIF performed with T_PAL is more stable than ALIF, especially during the recovery phase.


Subject(s)
Lumbar Vertebrae/surgery , Lumbosacral Region/surgery , Minimally Invasive Surgical Procedures , Spinal Fusion , Biomechanical Phenomena , Finite Element Analysis , Humans , Ligaments/pathology , Prostheses and Implants , Reproducibility of Results , Rotation , Stress, Mechanical
15.
Biomech Model Mechanobiol ; 18(3): 829-843, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30635851

ABSTRACT

During vaginal delivery women sustain stretching of their pelvic floor, risking tissue injury and adverse outcomes. Since studies in pregnant women are limited with ethical constraints, computational models have become an interesting alternative to elucidate the pregnancy mechanisms. This research investigates the uterine contractions during foetus expulsion without an imposed trajectory. Such physical process is captured by means of a chemo-mechanical constitutive model, where the uterine contractions are triggered by chemical stimuli. The foetus descent, which includes both pushing and resting stages, has a descent rate within the physiological range. Moreover, the behaviour of the foetus and the uterus stretch agree well with clinical data presented in the literature. The follow-up of this study will be to obtain a complete childbirth simulation, considering also the pelvic floor muscles and its supporting structures. The simulation of a realistic rate of descent, including the pushing and resting stages, is of significant importance to study the pelvic floor muscles due to their viscoelastic nature.


Subject(s)
Computer Simulation , Fetus/physiology , Models, Biological , Uterine Contraction/physiology , Biomechanical Phenomena , Finite Element Analysis , Humans , Kinetics , Muscle, Smooth/physiology , Myosins/metabolism , Parturition/physiology , Phosphorylation , Stress, Mechanical
16.
J Mech Behav Biomed Mater ; 88: 120-126, 2018 12.
Article in English | MEDLINE | ID: mdl-30170191

ABSTRACT

Injuries sustained by the pelvic floor muscles during childbirth are one of the major risk factors for the development of pelvic floor dysfunctions. The ability to predict the loss of the tissue integrity and the most affected regions prior to the childbirth would represent a compelling difference in choosing the appropriate management of labour. Previous biomechanical studies, using the finite element method, were able to simulate a vaginal delivery and analyse the mechanical effects on the pelvic floor muscles during the passage of the foetus. Complementing these studies, the aim of this work is to improve the characterization of the pelvic floor muscles, by using an anisotropic visco-hyperelastic constitutive model, including a continuum mechanics damage model. Viscoelasticity is a key feature to obtain more realistic results since biological tissues present relaxation effects that allow larger deformations without damage. This work analyses the reaction forces and the loss of tissue integrity sustained by the pelvic floor and evaluates the effects of different durations of labour. A delaying pushing technique of rest and descend is also studied in this work. The results obtained showed that the reaction forces vary with the duration of labour, with higher force levels associated with higher stretch rates. The pubovisceral muscle is the most affected of the levator ani, presenting an affected region of approximately 30%. The relaxation properties of the tissue contribute to diminish the damage levels, supporting the theory of delayed pushing applied in the second stage of labour.


Subject(s)
Delivery, Obstetric , Elasticity , Mechanical Phenomena , Models, Biological , Anisotropy , Biomechanical Phenomena , Time Factors , Viscosity
17.
Clin Ter ; 169(4): e184-e188, 2018.
Article in English | MEDLINE | ID: mdl-30151552

ABSTRACT

OBJECTIVE: The objectives of this work were to fill the gap in the scientific literature and to evaluate the results of physical therapy treatments in individuals affected by chronic fatigue syndrome, considering only studies that employed a randomized controlled trial. METHODS: A systematic review was carried out according to PRISMA guidelines. Three bibliographic databases were searched: MEDLINE, Cochrane Library, and PEDro. The minimum prerequisites for papers to be included in the systematic review were that they had to (a) employ a randomized controlled trial; (b) be published in English; and (c) be published during the last ten years (2007-2017). The studies were evaluated according to Jadad score. RESULTS: Four studies were included. This systematic review suggests that a treatment that is more effective than all the others cannot be defined. This conclusion is related to the low number of investigated studies; therefore, the collected results cannot be generalized. CONCLUSION: Chronic fatigue syndrome is not yet a well-understood pathology, and the physical mechanisms that influence the outcomes still need more study. Rehabilitation programs that promote physiotherapy techniques such as exercise, mobilization, and body awareness (e.g., MRT and GET) are the most effective in reducing medium and long-term fatigue severity in CFS patients.


Subject(s)
Exercise Therapy/methods , Fatigue Syndrome, Chronic/therapy , Physical Therapy Modalities , Exercise , Humans , Physical Examination , Quality of Life , Randomized Controlled Trials as Topic
18.
J Biomech ; 71: 100-110, 2018 04 11.
Article in English | MEDLINE | ID: mdl-29454543

ABSTRACT

The mechanical characteristics of the female pelvic floor are relevant to understand pelvic floor dysfunctions (PFD), and how they are related with changes in their biomechanical behavior. Urinary incontinence (UI) and pelvic organ prolapse (POP) are the most common pathologies, which can be associated with changes in the mechanical properties of the supportive structures in the female pelvic cavity. PFD have been studied through different methods, from experimental tensile tests using tissues from fresh female cadavers or tissues collected at the time of a transvaginal hysterectomy procedure, or by applying imaging techniques. In this work, an inverse finite element analysis (FEA) was applied to understand the passive and active behavior of the pubovisceralis muscle (PVM) during Valsalva maneuver and muscle active contraction, respectively. Individual numerical models of women without pathology, with stress UI (SUI) and POP were built based on magnetic resonance images, including the PVM and surrounding structures. The passive and active material parameters obtained for a transversely isotropic hyperelastic constitutive model were estimated for the three groups. The values for the material constants were significantly higher for the women with POP when compared with the other two groups. The PVM of women with POP showed the highest stiffness. Additionally, the influence of these parameters was analyzed by evaluating their stress-strain, and force-displacements responses. The force produced by the PVM in women with POP was 47% and 82% higher when compared to women without pathology and with SUI, respectively. The inverse FEA allowed estimating the material parameters of the PVM using input information acquired non-invasively.


Subject(s)
Mechanical Phenomena , Muscle Contraction , Pelvic Floor/physiology , Pelvic Organ Prolapse/physiopathology , Urinary Incontinence, Stress/physiopathology , Adolescent , Adult , Aged , Female , Finite Element Analysis , Humans , Magnetic Resonance Imaging/methods , Middle Aged , Pelvic Floor/diagnostic imaging , Pelvic Organ Prolapse/diagnostic imaging , Urinary Incontinence , Urinary Incontinence, Stress/diagnostic imaging , Valsalva Maneuver , Young Adult
19.
Article in English | MEDLINE | ID: mdl-28886617

ABSTRACT

During vaginal delivery, women sustain stretching of their pelvic floor, risking tissue injury and adverse outcomes. Realistic numerical simulations of childbirth can help in the understanding of the pelvic floor mechanics and on the prevention of related disorders. In previous studies, biomechanical finite element simulations of a vaginal delivery have been performed disregarding the viscous effects present on all biological soft tissues. The inclusion of the viscoelastic behaviour is fundamental, since it allows to investigate rate-dependent responses. The present work uses a viscohyperelastic constitutive model to evaluate how the childbirth duration affects the efforts sustained by the pelvic floor during delivery. It was concluded that viscoelasticity adds a stiffness component that leads to higher forces comparing with the elastic response. Viscous solutions are rate dependent, and precipitous labours could be associated to higher efforts, while lower reaction forces were denoted for normal and prolonged labours, respectively. The existence of resting stages during labour demonstrated the capability of the tissue to relax and recover some of the initial properties, which helped to lower the forces and stresses involved. The present work represents a step further in achieving a robust non-invasive procedure, allowing to estimate how obstetrical factors influence labour and its outcomes.


Subject(s)
Computer Simulation , Parturition , Pelvic Floor , Adult , Female , Finite Element Analysis , Humans , Models, Biological , Pregnancy , Viscosity
20.
Occup Ther Int ; 2017: 6474761, 2017.
Article in English | MEDLINE | ID: mdl-29097975

ABSTRACT

BACKGROUND: Disasters are increasingly more frequent events on our planet. During disaster the role of the occupational therapist will require a more specific operative framework within nongovernmental organizations and community health services. DESIGN: Systematic review. OBJECTIVE: The aim of this study is to evaluate the evidence that highlight occupational therapist's role in disaster area through a systematic review. MATERIALS AND METHODS: Research on MEDLINE was performed. All articles from 2005 to 2015 concerning rehabilitation and occupational therapy in disaster areas were included. RESULTS: Ten studies were selected to be included in this review. Four interesting points emerged: the importance of having rehabilitation intervention in postdisaster situations, the necessity to include a rehabilitation team in the early phase of disaster response, the need to provide a method to address the difficult evacuation, and finding the safest method of transport of people with preexisting disabilities and new injuries. CONCLUSIONS: The amount of evidence with respect to specific intervention of the occupational therapist's role in a disaster situation is limited. However some evidence suggests that it could be a good means for reducing the number of medical complications and deaths of persons with preexisting disabilities. The evidences found highlight the necessity to create a multidisciplinary team addressing needs in disasters situation, in which the occupational therapist could certainly contribute.


Subject(s)
Disasters , Occupational Therapists/statistics & numerical data , Occupational Therapy/organization & administration , Disabled Persons/rehabilitation , Humans
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