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2.
Sci Rep ; 12(1): 1542, 2022 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-35091669

RESUMO

We study the critical dynamics of vortices associated with dynamic disordering near the depinning transitions driven by dc force (dc current I) and vortex density (magnetic field B). Independent of the driving parameters, I and B, we observe the critical behavior of the depinning transitions, not only on the moving side, but also on the pinned side of the transition, which is the first convincing verification of the theoretical prediction. Relaxation times, [Formula: see text] and [Formula: see text], to reach either the moving or pinned state, plotted against I and B, respectively, exhibit a power-law divergence at the depinning thresholds. The critical exponents of both transitions are, within errors, identical to each other, which are in agreement with the values expected for an absorbing phase transition in the two-dimensional directed-percolation universality class. With an increase in B under constant I, the depinning transition at low B is replaced by the repinning transition at high B in the peak-effect regime. We find a trend that the critical exponents in the peak-effect regime are slightly smaller than those in the low-B regime and the theoretical one, which is attributed to the slight difference in the depinning mechanism in the peak-effect regime.

3.
Curr Biol ; 31(3): R116-R117, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33561405

RESUMO

Surprisingly, the fastest motions are not produced by large animals or robots. Rather, small organisms or structures, including cnidarian stinging cells, fungal shooting spores, and mandible strikes of ants, termites, and spiders, hold the world acceleration records.1-5 These diverse systems share common features: they rapidly convert potential energy - stored in deformed material or fluid - into kinetic energy when a latch is released.4-6 However, the fastest of these are not repeatable, because mechanical components are broken or ejected.5,6 Furthermore, some of these systems must overcome the added challenge of moving in water, where high density and viscosity constrain acceleration at small sizes. Here we report the kinematics of repeatable, ultrafast snaps by tiny marine amphipods (Dulichiella cf. appendiculata). Males use their enlarged major claw, which can exceed 30% of body mass, to snap a 1 mm-long dactyl with a diameter equivalent to a human hair (184 µm). The claw snaps closed extremely rapidly, averaging 93 µs, 17 m s-1, and 2.4 x 105 m s-2. These snaps are among the smallest and fastest of any documented repeatable movement, and are sufficiently fast to operate in the inertial hydrodynamic regime (Reynolds number (Re) >10,000). They generate audible pops and rapid water jets, which occasionally yield cavitation, and may be used for defense. These amphipod snaps push the boundaries of acceleration and size for repeatable movements, particularly in water, and exemplify how new biomechanical insights can arise from unassuming animals. VIDEO ABSTRACT.


Assuntos
Anfípodes , Movimento , Animais , Fenômenos Biomecânicos , Humanos , Masculino , Água
4.
J Nutr Health Aging ; 23(6): 564-570, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31233079

RESUMO

OBJECTIVES: To assess the effects of 24 months training on muscle quality, size, strength, and gait abilities in older adults who need long-term care. DESIGN: Non-randomized controlled trial Setting: Kawai Rehabilitation Center and Kajinoki Medical Clinic. PARTICIPANTS: Ten older participants who needed long-term care (age, 76.7 ± 5.6 years) were participated as training group (Tr-group) and 10 older men and women who did not require long-term care (age, 72.9 ± 6.6 years) comprised the control group (Cont-group). INTERVENTION: Tr-group performed resistive and endurance exercises once or twice a week for 24 months. MEASUREMENTS: Using ultrasound images, echo intensity (EI) and muscle thickness were measured in the rectus femoris and biceps femoris as an index of muscle quality and size. Physical performance was measured before and after the training; performance parameters included knee extension peak torque, 5-m normal and maximal walk test, sit-to-stand and timed up and go test. RESULTS: After the training, there was no change in EI, while BF thickness was increased (pre; 1.82 ± 0.29 cm, 24 months; 2.14 ± 0.23 cm, p < 0.05) in Tr-group. Walk-related performances were improved after the training in Tr-group (i.e. 5-m walk test and timed up and go test). The percent change of knee extension peak torque explained the percent change of EI in the rectus femoris (regression coefficient = 1.24, R = 0.91, adjusted R2 = 0.82, p < 0.001). CONCLUSIONS: Twenty-four months' training induced muscle hypertrophy and improved physical functions. Increased muscle quality in the rectus femoris could be a key to improved knee extension peak torque, with the potential to eventually reduce the need for long-term care in older individuals.


Assuntos
Treino Aeróbico/métodos , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Treinamento Resistido/métodos , Idoso , Feminino , Humanos , Assistência de Longa Duração , Masculino , Resistência Física/fisiologia , Fatores de Tempo
5.
Clin Exp Obstet Gynecol ; 44(2): 299-300, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29746045

RESUMO

CASE REPORT: A 30-year-old Japanese nulliparous woman visited for pregnancy at 33 weeks with a massive ovarian tumor located in the pouch of Douglas. By preoperative screening, her prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged, and her FV activity was significantly decreased to 4.8%. After prophylactic FFP 20 ml/kg was administered and her FV factor was 19.3%, cesarean delivery was performed, and her perioperative course was uneventful. One year later, she underwent a dilatation and evacuation because of a missed abortion, although prophylactic FFP was not administered. During a third pregnancy, after prophylactic FFP 20 ml/kg was administered and FV activity increased to 21.1%, elective cesarean delivery was performed, and her postoperative course was uneventful. CONCLUSION: For surgical therapy or delivery, the goal of therapy is to maintain FV activity above 20%. It is particularly useful to administer prophylactic FFP.


Assuntos
Cesárea/métodos , Deficiência do Fator V , Complicações do Trabalho de Parto/prevenção & controle , Plasma , Complicações Hematológicas na Gravidez , Deficiência do Fator V/diagnóstico , Deficiência do Fator V/terapia , Feminino , Humanos , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/cirurgia , Ovariectomia/métodos , Tempo de Tromboplastina Parcial/métodos , Gravidez , Complicações Hematológicas na Gravidez/diagnóstico , Complicações Hematológicas na Gravidez/terapia , Complicações Neoplásicas na Gravidez/patologia , Resultado da Gravidez , Resultado do Tratamento
6.
Nutr Diabetes ; 6(11): e233, 2016 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-27892934

RESUMO

Expression of ß-Kotho, fibroblast growth factor receptor (FGFR)-1c and 2c, which bind FGF21, is decreased in the white adipose tissue of obese mice. The aim of the present study was to determine the role of FGFR2c in the development of obesity and diabetes in KKAy mice. Treatment with mouse monoclonal FGFR2-IIIc antibody (0.5 mg kg-1) significantly suppressed body weight gain and epididymal white adipose tissue weight in individually housed KKAy mice while having no effect on daily food intake. In addition, treatment with FGFR2-IIIc antibody significantly increased plasma-free fatty acid levels while having no effect on blood glucose or plasma FGF21 levels. Moreover, treatment with FGFR2-IIIc antibody had no significant effect on the expression of uncoupling protein-1, uncoupling protein-2 or peroxisome proliferator-activated receptor-γ coactivator 1α in the epididymal white adipose tissue. The treatment with FGFR2-IIIc antibody had no significant effects on daily food intake and body weight gain in individually housed KK mice. These findings suggest that FGFR2-IIIc upregulates the adiposity induced by social isolation in KKAy mice, and that decreased expression and/or function of FGFR2c might be a compensatory response to enhanced adiposity. Inhibition of FGFR2-IIIc function might be a novel therapeutic approach for obesity.


Assuntos
Tecido Adiposo/efeitos dos fármacos , Anticorpos Monoclonais/farmacologia , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/imunologia , Aumento de Peso/efeitos dos fármacos , Animais , Anticorpos Monoclonais/administração & dosagem , Injeções Intraperitoneais , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Obesos
8.
Diabetes Metab ; 41(5): 425-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26234524

RESUMO

AIM: Glucagon-like peptide-1 (GLP-1), an incretin hormone, is released from intestinal L cells in response to nutrient ingestion. Dipeptidyl peptidase-4 (DPP-4) rapidly degrades the active form of GLP-1 to an inactive form in the bloodstream. The present study aimed to investigate the role of serotonin (5-HT)1B receptors in the regulation of plasma active GLP-1 levels and glucose tolerance under DPP-4 inhibition. METHODS: C57BL6J mice treated with or without alogliptin, a highly selective DPP-4 inhibitor, for 4 days were intraperitoneally injected with either saline, the 5-HT1B/2C receptor agonist meta-chlorophenylpiperazine (mCPP) at 2.5mg/kg and 5mg/kg or the selective 5-HT1B receptor agonist CP94253 at 2.5mg/kg and 5mg/kg, and food-deprived after treatment. An hour later, plasma active GLP-1 levels were determined. Also, a glucose tolerance test was done by injecting D-glucose (2g/kg) following the injection of saline or CP94253 (5mg/kg) in mice treated with alogliptin. RESULTS: Intraperitoneal injection of mCPP (2.5 and 5mg/kg) or CP94253 (2.5 and 5mg/kg) in mice treated with alogliptin for 4 days significantly increased plasma active GLP-1 levels compared with saline controls in mice that were food-deprived after the injections. While intraperitoneal injection of either mCPP or CP94253 alone had no significant effect on plasma active GLP-1 levels, the injection of CP94253 improved glucose tolerance in mice treated with alogliptin compared with saline. CONCLUSION: These findings suggest that pharmacological stimulation of 5-HT1B receptors enhances the increases in plasma active GLP-1 induced by DPP-4 inhibition independently of feeding and also improves glucose tolerance in mice.


Assuntos
Dipeptidil Peptidase 4/metabolismo , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Peptídeo 1 Semelhante ao Glucagon/agonistas , Intolerância à Glucose/tratamento farmacológico , Receptor 5-HT1B de Serotonina/metabolismo , Agonistas do Receptor 5-HT1 de Serotonina/uso terapêutico , Regulação para Cima/efeitos dos fármacos , Administração Oral , Animais , Dipeptidil Peptidase 4/genética , Inibidores da Dipeptidil Peptidase IV/administração & dosagem , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Interações Alimento-Droga , Peptídeo 1 Semelhante ao Glucagon/sangue , Intolerância à Glucose/sangue , Intolerância à Glucose/metabolismo , Injeções Intraperitoneais , Insulina/agonistas , Insulina/sangue , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Piperazinas/administração & dosagem , Piperazinas/uso terapêutico , Piperidinas/administração & dosagem , Piperidinas/uso terapêutico , Piridinas/administração & dosagem , Piridinas/uso terapêutico , Receptor 5-HT1B de Serotonina/química , Agonistas do Receptor 5-HT1 de Serotonina/administração & dosagem , Uracila/administração & dosagem , Uracila/análogos & derivados , Uracila/uso terapêutico
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