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1.
Diabetologia ; 66(9): 1719-1734, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37301795

RESUMO

AIMS/HYPOTHESIS: Non-invasive in vivo corneal confocal microscopy is gaining ground as an alternative to skin punch biopsy to evaluate small-diameter nerve fibre characteristics. This study aimed to further explore corneal nerve fibre pathology in diabetic neuropathy. METHODS: This cross-sectional study quantified and compared corneal nerve morphology and microneuromas in participants without diabetes (n=27), participants with diabetes but without distal symmetrical polyneuropathy (DSPN; n=33), participants with non-painful DSPN (n=25) and participants with painful DSPN (n=18). Clinical and electrodiagnostic criteria were used to diagnose DSPN. ANCOVA was used to compare nerve fibre morphology in the central cornea and inferior whorl, and the number of corneal sub-epithelial microneuromas between groups. Fisher's exact tests were used to compare the type and presence of corneal sub-epithelial microneuromas and axonal swelling between groups. RESULTS: Various corneal nerve morphology metrics, such as corneal nerve fibre length and density, showed a progressive decline across the groups (p<0.001). In addition, axonal swelling was present more frequently (p=0.018) and in higher numbers (p=0.03) in participants with painful compared with non-painful DSPN. The frequency of axonal distension, a type of microneuroma, was increased in participants with painful and non-painful DSPN compared to participants with diabetes but without DSPN and participants without diabetes (all p≤0.042). The combined presence of all microneuromas and axonal swelling was increased in participants with painful DSPN compared with all other groups (p≤0.026). CONCLUSIONS/INTERPRETATION: Microneuromas and axonal swelling in the cornea increase in prevalence from participants with diabetes to participants with non-painful DSPN and participants with painful DSPN.


Assuntos
Diabetes Mellitus Tipo 2 , Neuropatias Diabéticas , Humanos , Estudos Transversais , Córnea/patologia , Dor , Pele/inervação , Microscopia Confocal , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/patologia
2.
Int J Biometeorol ; 67(7): 1273-1277, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37191730

RESUMO

Heat stress negatively affects livestock, with undesirable effects on animals' production and reproduction. Temperature and humidity index (THI) is a climatic variable used worldwide to study the effect of heat stress on farm animals. Temperature and humidity data can be obtained in Brazil through the National Institute of Meteorology (INMET), but complete data may not be available due to temporary failures on weather stations. An alternative to obtaining meteorological data is the National Aeronautics and Space Administration Prediction of Worldwide Energy Resources (NASA POWER) satellite-based weather system. We aimed to compare THI estimates obtained from INMET weather stations and NASA POWER meteorological information sources using Pearson correlation and linear regression. After quality check, data from 489 INMET weather stations were used. The hourly, average daily and maximum daily THI were evaluated. We found greater correlations and better regression evaluation metrics when average daily THI values were considered, followed by maximum daily THI, and hourly THI. NASA POWER satellite-based weather system is a suitable tool for obtaining the average and maximum THI values using information collected from Brazil, showing high correlations with THI estimates from INMET and good regression evaluation metrics, and can assist studies that aim to analyze the impact of heat stress on livestock production in Brazil, providing additional data to complement the existing information available in the INMET database.


Assuntos
Transtornos de Estresse por Calor , Meteorologia , Animais , Estados Unidos , Feminino , Umidade , Temperatura , Brasil , United States National Aeronautics and Space Administration , Tempo (Meteorologia) , Transtornos de Estresse por Calor/veterinária , Temperatura Alta , Lactação , Leite
3.
Int J Phytoremediation ; : 1-11, 2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38059299

RESUMO

Soil contamination by toxic metals threatens global public health, highlighting the need for cost-effective and ecologically sound site remediation. In this study, we assessed phytoremediation of Hg-contaminated soils by Emilia fosbergii Nicolson (Asteraceae). Pot experiment was conducted using a substrate of sand and vermiculite (1:1 volume ratio), treatments consisted of five Hg concentrations (0, 1, 3, 5, and 7 mg kg-1). Metal transfer rates were calculated, including accumulation (BAF), translocation (TF) and bioconcentration (BCF) factors. E. fosbergii roots exhibited greater Hg accumulation than other tissues, but biomass production and plant health were not significantly affected at the concentrations tested, as indicated by elongation factors and tolerance index. The results revealed BAF values between 2.18 and 7.14, TF values ranged between 0.15 and 0.52, and the BCF index varied between 8.97 and 26.58. Treatments with Hg content of 5 mg kg-1 and 7 mg kg-1 recorded the highest total Hg concentrations of 66 mg kg-1 and 65.53 mg kg-1 (roots), and 9.18 mg kg-1 and 33.88 mg kg-1 (aerial), respectively. E. fosbergii demonstrated promise for Hg phytoremediation due to its high accumulation capacity, indicated by regular TF and high BCF and BAF indexes, thus classifying it as a high Hg accumulator.


Phytoextractor and phytostabilizer plant, high accumulator of Hg.Weed with great capacity for proliferation and adaptability.E. fosbergii showed tolerance to Hg in the substrate.Promising plant for phytoremediation of soils contaminated by Hg.Novel species for recovery of soils degraded by Hg exposure.

4.
Sensors (Basel) ; 24(1)2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38203110

RESUMO

Lower limb exoskeletons and orthoses have been increasingly used to assist the user during gait rehabilitation through torque transmission and motor stability. However, the physical human-robot interface (HRi) has not been properly addressed. Current orthoses lead to spurious forces at the HRi that cause adverse effects and high abandonment rates. This study aims to assess and compare, in a holistic approach, human-robot joint misalignment and gait kinematics in three fixation designs of ankle-foot orthoses (AFOs). These are AFOs with a frontal shin guard (F-AFO), lateral shin guard (L-AFO), and the ankle modulus of the H2 exoskeleton (H2-AFO). An experimental protocol was implemented to assess misalignment, fixation displacement, pressure interactions, user-perceived comfort, and gait kinematics during walking with the three AFOs. The F-AFO showed reduced vertical misalignment (peak of 1.37 ± 0.90 cm, p-value < 0.05), interactions (median pressures of 0.39-3.12 kPa), and higher user-perceived comfort (p-value < 0.05) when compared to H2-AFO (peak misalignment of 2.95 ± 0.64 and pressures ranging from 3.19 to 19.78 kPa). F-AFO also improves the L-AFO in pressure (median pressures ranging from 8.64 to 10.83 kPa) and comfort (p-value < 0.05). All AFOs significantly modified hip joint angle regarding control gait (p-value < 0.01), while the H2-AFO also affected knee joint angle (p-value < 0.01) and gait spatiotemporal parameters (p-value < 0.05). Overall, findings indicate that an AFO with a frontal shin guard and a sports shoe is effective at reducing misalignment and pressure at the HRI, increasing comfort with slight changes in gait kinematics.


Assuntos
Órtoses do Pé , Robótica , Humanos , Fenômenos Biomecânicos , Tornozelo , Marcha
5.
Environ Monit Assess ; 195(4): 477, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36928432

RESUMO

The spatial distribution and dispersion of mercury (Hg) is associated with the structural conditions of the environment, primarily land use and vegetation cover. Man-made emissions of the metal from activities such as artisanal and small-scale gold mining (ASGM) can influence this distribution. Forest ecosystems are of particular importance as they constitute one of the most active environments in the biogeochemical cycle of Hg, and understanding these dynamics is essential to better understand its global cycle. In this study, we determined the content of Hg present in different forest strata (soil, leaf litter, herbaceous, underwood/bush, and arboreal), as well as the relationship between the presence of Hg and the landscape heterogeneity, percentage of gold mines, and ground slope. This study was carried out in tropical forest areas of the southern Brazilian Amazon. Accumulation and transport of Hg between forest strata was assessed in order to understand the influence of these forest environments on Hg accumulation in areas where ASGM occurs. We verified that there is a difference in Hg content between forest strata, indicating that atmospheric Hg is accumulated onto the arboreal stratum and transported vertically to strata below the canopy, i.e., underwood/bush and herbaceous, and subsequently accumulated in the leaf litter and transferred to the soil. Leaf litter was the stratum with the highest Hg content, characterized as a receptor for most of the Hg load from the upper strata in the forest. Therefore, it was confirmed that Hg accumulation dynamics are at play between the areas analyzed due to the proximity of ASGMs in the region. This indicates that the conservation of forest areas plays an important role in the process of atmospheric Hg deposition and accumulation, acting as a mercury sink in areas close to man-made emissions.


Assuntos
Mercúrio , Humanos , Mercúrio/análise , Brasil , Ecossistema , Ouro/análise , Monitoramento Ambiental , Florestas , Árvores , Plantas , Mineração , Solo/química
6.
Bioinformatics ; 36(2): 514-523, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31504164

RESUMO

MOTIVATION: Analysis of differential expression of genes is often performed to understand how the metabolic activity of an organism is impacted by a perturbation. However, because the system of metabolic regulation is complex and all changes are not directly reflected in the expression levels, interpreting these data can be difficult. RESULTS: In this work, we present a new algorithm and computational tool that uses a genome-scale metabolic reconstruction to infer metabolic changes from differential expression data. Using the framework of constraint-based analysis, our method produces a qualitative hypothesis of a change in metabolic activity. In other words, each reaction of the network is inferred to have increased, decreased, or remained unchanged in flux. In contrast to similar previous approaches, our method does not require a biological objective function and does not assign on/off activity states to genes. An implementation is provided and it is available online. We apply the method to three published datasets to show that it successfully accomplishes its two main goals: confirming or rejecting metabolic changes suggested by differentially expressed genes based on how well they fit in as parts of a coordinated metabolic change, as well as inferring changes in reactions whose genes did not undergo differential expression. AVAILABILITY AND IMPLEMENTATION: github.com/htpusa/moomin. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Redes e Vias Metabólicas , Algoritmos , Biologia Computacional , Genoma , Modelos Biológicos
7.
Environ Monit Assess ; 193(8): 537, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34331150

RESUMO

Aquatic plants are considered to be important remedial agents in aquatic environments contaminated by metals. The Salvinia biloba macrophyte was evaluated in relation to its removal kinetics, adsorption capacity, and toxicology, aiming at its application in the removal of Cd+2 and Pb+2 ions from aqueous solutions. A batch-type system was used, in which the plants were cultivated in microcosms containing nutritive solution and metallic ions, stored in a controlled environment (pH, temperature, and luminosity). The removal kinetics consisted in the analysis of efficiency, varying the concentrations of the metals, and time of cultivation of plants in solution. To describe the process, adsorption isotherms were constructed with the equilibrium data, which were later adjusted to Langmuir and Freundlich models. The toxicological trial was performed by sub-acute exposure test of Caenorhabditis elegans nematode to phytoremediated solutions. The results highlight the remedial effect of the plant in solutions contaminated with both metals. The kinetic study demonstrated that the plant responds differently to metals, and physical-chemical and biological processes can be attributed to the removal of metals from the solution by the plant. The equilibrium time obtained was 48 h for both metals, and the adsorption capacity was higher for Cd2+. The toxicological evaluation indicates that there was a reduction in toxicity after the remediation of the solutions by S. biloba, for all times and concentrations evaluated. Salvinia biloba was efficient for the removal of Cd2+ and Pb2+ metals from aqueous solution. The plant is a low-cost metal biosorbent and can be considered promising for phytoremediation strategies in liquid effluents and water bodies.


Assuntos
Cádmio , Poluentes Químicos da Água , Adsorção , Biomassa , Cádmio/análise , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Cinética , Chumbo , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
8.
BMC Bioinformatics ; 21(1): 69, 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32093622

RESUMO

BACKGROUND: In this paper, we explore the concept of multi-objective optimization in the field of metabolic engineering when both continuous and integer decision variables are involved in the model. In particular, we propose a multi-objective model that may be used to suggest reaction deletions that maximize and/or minimize several functions simultaneously. The applications may include, among others, the concurrent maximization of a bioproduct and of biomass, or maximization of a bioproduct while minimizing the formation of a given by-product, two common requirements in microbial metabolic engineering. RESULTS: Production of ethanol by the widely used cell factory Saccharomyces cerevisiae was adopted as a case study to demonstrate the usefulness of the proposed approach in identifying genetic manipulations that improve productivity and yield of this economically highly relevant bioproduct. We did an in vivo validation and we could show that some of the predicted deletions exhibit increased ethanol levels in comparison with the wild-type strain. CONCLUSIONS: The multi-objective programming framework we developed, called MOMO, is open-source and uses POLYSCIP (Available at http://polyscip.zib.de/). as underlying multi-objective solver. MOMO is available at http://momo-sysbio.gforge.inria.fr.


Assuntos
Engenharia Metabólica/métodos , Software , Biomassa , Etanol/metabolismo , Modelos Biológicos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
9.
J Ultrasound Med ; 39(4): 675-681, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31633231

RESUMO

OBJECTIVES: Neurodynamic techniques are often used to treat people with sciatica pain, but their mechanical effects on the sciatic nerve are unknown. Shear wave elastography (SWE) has been shown to effectively estimate the stiffness of peripheral nerves in real time. The aim of this study was to use SWE to assess the effects of slump neurodynamics in the sciatic stiffness of people with sciatica. METHODS: Sixteen participants volunteered for this study. The sciatic stiffness of 8 patients with unilateral chronic sciatica and 8 healthy control participants was measured by SWE, with the participants in a prone position and during a dynamic condition (ie, ankle dorsiflexion). These measurements were performed before and immediately after the neurodynamic intervention, which consisted of a static slump position applied to the symptomatic limb of the patients with sciatica and in a randomly chosen limb of the healthy participants. RESULTS: The 8 patients with sciatica included 6 male and 2 female patients, and the 8 healthy control participants included 5 male and 3 female volunteers. Slump neurodynamics resulted in an immediate decrease in the sciatic nerve stiffness of the symptomatic limb in people with sciatica by 16.1% (effect size = 0.65; P = .019). The intervention showed no significant changes in the sciatic nerve stiffness of the healthy participants (effect size = 0.05; P = .754). CONCLUSIONS: Slump neurodynamics have the potential of decreasing the sciatic nerve stiffness in people with sciatica, and this effect can be quantified by SWE, which may provide valuable information for health professionals.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Manipulações Musculoesqueléticas/métodos , Ciática/diagnóstico por imagem , Ciática/terapia , Adulto , Feminino , Humanos , Masculino , Postura/fisiologia , Nervo Isquiático/diagnóstico por imagem , Nervo Isquiático/fisiopatologia , Ciática/fisiopatologia , Resultado do Tratamento
10.
J Anim Breed Genet ; 137(5): 486-494, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31646684

RESUMO

The present study evaluated the heat stress response pattern of dual-purpose Guzerá cattle for test-day (TD) milk yield records of first lactation and estimated genetic parameters and trends related to heat stress. A total of 31,435 TD records from 4,486 first lactations of Guzerá cows, collected between 1986 and 2012, were analysed. Two random regression models considered days in milk (DIM) and/or temperature × humidity-dependent (THI) covariate. Impacts of -0.037, -0.019 and -0.006 kg/day/THI for initial and intermediate stages of lactation were observed when considering the mean maximum daily temperature and humidity to calculate THI. Heritability estimates ranged from 0.16 to 0.35 throughout lactation and THI values, suggesting the possibility to expect gains from selection for such trait. The variable trajectory of breeding values for dual-purpose Guzerá sires in response to changes in THI values confirms that the genotype × environment interaction due to heat stress can have some effect on TD milk yield. Despite the high dairy performance of Guzerá cattle under heat stress, estimated genetic trends showed a progressive reduction in heat tolerance. Therefore, new strategies should be adopted to prevent negative impacts of heat stress over milk production in Guzerá animals in future.


Assuntos
Cruzamento , Transtornos de Estresse por Calor/genética , Resposta ao Choque Térmico/genética , Lactação/genética , Animais , Bovinos , Feminino , Variação Genética/genética , Genótipo , Transtornos de Estresse por Calor/patologia , Resposta ao Choque Térmico/fisiologia , Temperatura Alta/efeitos adversos
12.
J Ultrasound Med ; 38(1): 157-164, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29732595

RESUMO

OBJECTIVES: The purpose of this study was to determine whether sciatic nerve stiffness is altered in people with chronic low back-related leg pain by using shear wave elastography. METHODS: In this cross-sectional study, the sciatic nerve shear wave velocity (ie, an index of stiffness) was measured in both legs of 16 participants (8 with unilateral low back-related leg pain and 8 healthy controls). Sciatic stiffness was measured during a passive ankle dorsiflexion motion performed at 2°/s in an isokinetic dynamometer. The ankle range of motion and passive torque, as well as muscle activity, were also measured. RESULTS: In people with low back-related leg pain, the affected limb showed higher sciatic nerve stiffness compared to the unaffected limb (+11.3%; P = .05). However, no differences were observed between the unaffected limb of people with low back-related leg pain and the healthy controls (P = .34). CONCLUSIONS: People with chronic low back-related leg pain have interlimb differences in sciatic nerve stiffness, as measured by a safe and noninvasive method: shear wave elastography. The changes found may be related to alterations in nerve mechanical properties, which should be confirmed by future investigations.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Dor Lombar/etiologia , Nervo Isquiático/diagnóstico por imagem , Nervo Isquiático/patologia , Neuropatia Ciática/diagnóstico por imagem , Neuropatia Ciática/patologia , Adolescente , Adulto , Dor Crônica/etiologia , Dor Crônica/fisiopatologia , Estudos Transversais , Eletromiografia , Feminino , Humanos , Perna (Membro)/fisiopatologia , Dor Lombar/fisiopatologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Phytother Res ; 33(3): 856-858, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30648299

RESUMO

Prolonged use of antiretroviral therapy (ART) has been associated with dyslipidemia and impaired energy substrate oxidation (SOxi). Curcumin is a natural bioactive compound, which interacts with molecular targets and holds important metabolic properties. The aim of this study was to evaluate the effect of curcumin supplementation on energetic metabolism of an adult female with HIV/AIDS and under ART. The intervention was performed with 500 mg/day of curcumin for 27 days. Glycemic and lipid profile and SOxi at rest were evaluated before and after intervention. After intervention, improvement of lipid profile and insulin sensibility was observed. Moreover, there was a positive modulation of SOxi at rest. Oral curcumin supplementation can positively modulate the energy metabolism of people living with HIV/AIDS using the ART. However, clinical studies are required in order to confirm our findings in a representative sample.


Assuntos
Curcumina/farmacologia , Metabolismo Energético/efeitos dos fármacos , Infecções por HIV/metabolismo , Adulto , Fármacos Anti-HIV/uso terapêutico , Feminino , Infecções por HIV/sangue , Infecções por HIV/tratamento farmacológico , Humanos , Lipídeos/sangue
14.
Environ Monit Assess ; 191(12): 751, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31732816

RESUMO

Plant-based materials are promising adsorbents for treating liquid effluents. This study describes the kinetic and equilibrium parameters that best represent the copper(II) and lead(II) removal process by Eichhornia crassipes (Aguapé) dry biomass from aqueous solution, using a batch adsorption system. The plants were washed, dried, and reduced to small particles. The adsorption kinetics were assessed by varying the metal concentrations in 5, 10, and 20 mg L-1 and a control treatment (without metals) with a mixture contact time of between 5 and 720 min. Equilibrium data were fitted to the Langmuir and Freundlich models. Kinetic assay revealed fast adsorption: kinetic equilibrium was attained within 2 h with a removal efficiency of ~ 60%. The results demonstrated a fast recovery cycle of metals using the biosorbent. The biomass of E. crassipes is low cost with potential for use as a biosorbent to remove metals from solutions.


Assuntos
Biodegradação Ambiental , Cobre/análise , Eichhornia/metabolismo , Chumbo/análise , Poluentes Químicos da Água/análise , Adsorção , Biomassa , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Cinética , Água/química
15.
Eur J Appl Physiol ; 118(3): 585-593, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29327169

RESUMO

PURPOSE: While several studies demonstrated the occurrence of intermuscular mechanical interactions, the physiological significance of these interactions remains a matter of debate. The purpose of this study was to quantify the localized changes in the shear modulus of the gastrocnemius lateralis (GL), monoarticular dorsi- and plantar-flexor muscles induced by a change in knee angle. METHOD: Participants underwent slow passive ankle rotations at the following two knee positions: knee flexed at 90° and knee fully extended. Ultrasound shear wave elastography was used to assess the muscle shear modulus of the GL, soleus [both proximally (SOL-proximal) and distally (SOL distal)], peroneus longus (PERL), and tibialis anterior (TA). This was performed during two experimental sessions (experiment I: n = 11; experiment II: n = 10). The shear modulus of each muscle was compared between the two knee positions. RESULTS: The shear modulus was significantly higher when the knee was fully extended than when the knee was flexed (P < 0.001) for the GL (averaged increase on the whole range of motion: + 5.8 ± 1.3 kPa), SOL distal (+ 4.5 ± 1.5 kPa), PERL (+ 1.1 ± 0.7 kPa), and TA (+ 1.6 ± 1.0 kPa). In contrast, a lower SOL-proximal shear modulus (P < 0.001, - 5.9 ± 1.0 kPa) was observed. CONCLUSION: As the muscle shear modulus is linearly related to passive muscle force, these results provide evidence of a non-negligible intermuscular mechanical interaction between the human lower leg muscles during passive ankle rotations. The role of these interactions in the production of coordinated movements requires further investigation.


Assuntos
Tornozelo/fisiologia , Articulação do Joelho/fisiologia , Músculo Esquelético/fisiologia , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Contração Muscular , Distribuição Aleatória
16.
J Anat ; 230(5): 639-650, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28251615

RESUMO

It is challenging to differentiate the mechanical properties of synergist muscles in vivo. Shear wave elastography can be used to quantify the shear modulus (i.e. an index of stiffness) of a specific muscle. This study assessed the passive behavior of lower leg muscles during passive dorsiflexion performed with the knee fully extended (experiment 1, n = 22) or with the knee flexed at 90° (experiment 2, n = 20). The shear modulus measurements were repeated twice during experiment 1 to assess the inter-day reliability. During both experiments, the shear modulus of the following plantar flexors was randomly measured: gastrocnemii medialis (GM) and lateralis (GL), soleus (SOL), peroneus longus (PL), and the deep muscles flexor digitorum longus (FDL), flexor hallucis longus (FHL), tibialis posterior (TP). Two antagonist muscles tibialis anterior (TA), and extensor digitorum longus (EDL) were also recorded. Measurements were performed in different proximo-distal regions for GM, GL and SOL. Inter-day reliability was adequate for all muscles (coefficient of variation < 15%), except for TP. In experiment 1, GM exhibited the highest shear modulus at 80% of the maximal range of motion (128.5 ± 27.3 kPa) and was followed by GL (67.1 ± 24.1 kPa). In experiment 2, SOL exhibited the highest shear modulus (55.1 ± 18.0 kPa). The highest values of shear modulus were found for the distal locations of both the GM (80% of participants in experiment 1) and the SOL (100% of participants in experiment 2). For both experiments, deep muscles and PL exhibited low levels of stiffness during the stretch in young asymptomatic adults, which was unknown until now. These results provide a deeper understanding of passive mechanical properties and the distribution of stiffness between and within the plantar flexor muscles during stretching between them and thus could be relevant to study the effects of aging, disease progression, and rehabilitation on stiffness.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Articulação do Joelho/fisiologia , Músculo Esquelético/fisiologia , Amplitude de Movimento Articular/fisiologia , Ergometria/métodos , Feminino , Humanos , Perna (Membro)/fisiologia , Masculino , Adulto Jovem
17.
Eur J Appl Physiol ; 117(10): 2047-2056, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28780603

RESUMO

PURPOSE: This study aimed to determine whether an increase in muscle shear modulus measured 30 min after eccentric exercise (30 min) reflects the magnitude of force deficit measured 48-h post-exercise (48 H). METHODS: A total of 53 healthy participants were distributed in five groups. Four groups performed either repeated eccentric elbow flexions or knee extensions at either a low or high load. A fifth group performed repeated concentric elbow flexions (control load). RESULTS: A significant decreased peak torque was found for elbow flexors and knee extensors 48 h after the eccentric exercises (all P values < 0.001). A significant increase in shear modulus was found at 30 min for the elbow flexors for low (+70.5 ± 44.3%, P < 0.001) and high load (+153.9 ± 192.4%, P < 0.001). Similarly, the shear modulus of knee extensors increased for low (+26.7 ± 19.1%, P < 0.001) and high load (+79.4 ± 67.1%, P < 0.001). The relative increase in shear modulus measured at 30 min was significantly correlated to the relative decrease in peak torque measured at 48 H for both elbow flexors (r = -0.80) and knee extensors (r = -0.82). A further analysis suggested that biceps brachii and rectus femoris were more affected by muscle damage than their synergists. CONCLUSION: This study shows that an increase in muscle shear modulus measured 30 min after a damaging exercise reflects the decrease in peak torque measured at 48 H. Shear modulus may therefore, provide a useful tool for coaches and clinicians to non-invasively estimate the amount of muscle damage induced by a damaging exercise.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Mialgia/diagnóstico por imagem , Condicionamento Físico Humano/efeitos adversos , Adulto , Feminino , Humanos , Contração Isométrica , Masculino , Força Muscular , Mialgia/etiologia , Torque
18.
Eur J Appl Physiol ; 117(1): 171-178, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27913924

RESUMO

PURPOSE: The neck extensor muscles contribute to spinal support and posture while performing head and neck motion. Muscle stiffness relates to passive elasticity (support) and active tensioning (posture and movement) of muscle. It was hypothesized that support and motion requirements are reflected in the distribution of stiffness between superficial and deep neck extensor muscles. METHODS: In ten healthy participants, shear modulus (stiffness) of five neck extensor muscles was determined in prone at rest and during isometric head lift at three intensities using shear wave elastography. RESULTS: Shear modulus differed between muscles (P < 0.001), and was larger for the deeper muscles: (median (interquartile range)) trapezius 7.7 kPa (4.4), splenius capitis 6.5 kPa (2.5), semispinalis capitis 8.9 kPa (2.8), semispinalis cervicis 9.5 kPa (2.5), multifidus 14.9 kPa (1.4). Shear modulus differed between the resting condition and head lift (P < 0.001) but not between levels of head lift intensity. CONCLUSION: Shear wave elastography revealed highest passive and active stiffness of the deep neck extensor muscles most close to the spine. The highest active increase of stiffness during the head lift was found in the semispinalis cervicis muscle. The non-invasive, clinically applicable estimates of muscle stiffness have potential for the assessment of muscular changes associated with neck pain/injury.


Assuntos
Elasticidade , Força Muscular , Músculos do Pescoço/diagnóstico por imagem , Adolescente , Adulto , Técnicas de Imagem por Elasticidade , Feminino , Humanos , Masculino , Músculos do Pescoço/fisiologia , Postura
19.
Sensors (Basel) ; 17(11)2017 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-29137198

RESUMO

Present day biomedical applications, including magnetic biosensing, demand better understanding of the interactions between living systems and magnetic nanoparticles (MNPs). In this work spherical MNPs of maghemite were obtained by a highly productive laser target evaporation technique. XRD analysis confirmed the inverse spinel structure of the MNPs (space group Fd-3m). The ensemble obeyed a lognormal size distribution with the median value 26.8 nm and dispersion 0.362. Stabilized water-based suspensions were fabricated using electrostatic or steric stabilization by the natural polymer chitosan. The encapsulation of the MNPs by chitosan makes them resistant to the unfavorable factors for colloidal stability typically present in physiological conditions such as pH and high ionic force. Controlled amounts of suspensions were used for in vitro experiments with human blood mononuclear leukocytes (HBMLs) in order to study their morphofunctional response. For sake of comparison the results obtained in the present study were analyzed together with our previous results of the study of similar suspensions with human mesenchymal stem cells. Suspensions with and without chitosan enhanced the secretion of cytokines by a 24-h culture of HBMLs compared to a control without MNPs. At a dose of 2.3, the MTD of chitosan promotes the stimulating effect of MNPs on cells. In the dose range of MNPs 10-1000 MTD, chitosan "inhibits" cellular secretory activity compared to MNPs without chitosan. Both suspensions did not caused cell death by necrosis, hence, the secretion of cytokines is due to the enhancement of the functional activity of HBMLs. Increased accumulation of MNP with chitosan in the cell fraction at 100 MTD for 24 h exposure, may be due to fixation of chitosan on the outer membrane of HBMLs. The discussed results can be used for an addressed design of cell delivery/removal incorporating multiple activities because of cell capability to avoid phagocytosis by immune cells. They are also promising for the field of biosensor development for the detection of magnetic labels.


Assuntos
Nanopartículas de Magnetita , Quitosana , Compostos Férricos , Humanos , Teste de Materiais , Eletricidade Estática , Suspensões , Água
20.
J Med Libr Assoc ; 105(1): 12-19, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28096741

RESUMO

OBJECTIVE: The authors undertook this project to learn how third-year medical students seek and use information in the course of daily activities, especially activities conducted in clinical settings in a variety of institutions. METHODS: We recruited sixty-eight third-year undergraduate medical school students to create a mapping diary of a day that included clinical activities. We conducted semi-structured interviews based on the mapping diaries. Using content and thematic analyses of the resulting interview transcripts, we developed an ethnographic case study for each participant. RESULTS: In the studied sample, we identified a broad range of information resources used for personal, clinical, and educational use. Participants relied heavily on technology throughout their day, including desktop computers, smart phones, handheld tablets, and laptops. Time management was a pervasive theme in the interviews, with participants squeezing in time to study for exams wherever and whenever they could. Selection of a particular information resource or technology to use was governed largely by the convenience of using that resource or technology. When obstacles were encountered, workarounds might be sought, but in many cases, the resource or technology would be abandoned in favor of a more convenient solution. Convenience was also a consideration in choosing spaces to use for clinical duties or for study, with specific considerations of available technology, proximity to clinical areas, and security for belongings contributing to choices made. CONCLUSIONS: Some of our results align with those of other recent studies of information use among medical students, residents, and practicing physicians. In particular, the fast-paced clinical setting favors use of information resources that are fast and easy to use. We demonstrated that the methods used are suitable to better understand clinicians' discovery and use of information.


Assuntos
Comportamento de Busca de Informação , Estudantes de Medicina/psicologia , Antropologia Cultural , Humanos , Entrevistas como Assunto , Informática Médica , Estudantes de Medicina/estatística & dados numéricos
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