Search results for "Contraction"

New Stage-Discharge Equation for the SMBF Flume

2016

AbstractFlumes for indirect discharge measurements are widespread and are characterized by a particular shape of the cross section area with various degrees of convergence and subsequent divergence. The flume named Samani, Magallanez, Baiamonte, Ferro (SMBF) is a simple and inexpensive instrument and its channel contraction is obtained by applying two semicylinders to the walls of a rectangular cross section. At first, in this paper a new stage-discharge equation for the SMBF flume is theoretically deduced. Then, this equation is experimentally calibrated using the laboratory measurements from the literature for different values of the contraction ratio. Finally the field measurements carri…

Validation of a subject specific 3-actuator torque-driven model in human vertical jumping.

2013

In this study, a forward dynamic subject specific 3-actuator torque-driven model of the human musculoskeletal system was created based on measurements of individual characteristics of a subject. Simulation results were compared with experimental vertical squat jumping with and without adding weights. By analyzing kinematic and kinetic experimental data at the instant of the toe-off for the same initial conditions, it was shown that a simple computer simulation using a suitable cost function could reproduce the real task performed by humans. This investigation is the first step in a wider project that will incorporate elastic components, and that will evaluate the advantages of the individua…

Recensione: MR2826706 Abbas, Mujahid; Hussain, Nawab; Rhoades, Billy E. Coincidence point theorems for multivalued f -weak contraction mappings and a…

2012

Nonlinear psi-quasi-contractions of Ciric-type in partial metric spaces

2012

In this paper we obtain results of fixed and common fixed points for self-mappings satisfying a nonlinear contractive condition of Ciric-type in the framework of partial metric spaces. We also prove results of fixed point for self-mappings satisfying an ordered nonlinear contractive condition in the setting of ordered partial metric spaces.

Common fixed point theorems for (ϕ, ψ)-weak contractions in fuzzy metric spaces

2010

Motivated by Rhoades (Nonlinear Anal., 47 (2001), 2683--2693), on the lines of Khan et al. (Bull. Aust. Math. Soc., 30 (1984), 1-9) employing the idea of altering distances, we extend the notion of (ϕ, ψ)-weak contraction to fuzzy metric spaces and utilize the same to prove common fixed point theorems for four mappings in fuzzy metric spaces.

Functional evidence for GABA as modulator of the contractility of the longitudinal muscle in mouse duodenum: Role of GABAA and GABAC receptors

2007

We investigated, in vitro, the effects of gamma-aminobutyric acid (GABA) on the spontaneous mechanical activity of the longitudinal smooth muscle in mouse duodenum. GABA induced an excitatory effect, consisting in an increase in the basal tone, which was antagonized by the GABA(A)-receptor antagonist, bicuculline, potentiated by (1,2,5,6-Tetrahydropyridin-4-yl)methylphosphinic acid hydrate (TPMPA), a GABA(C)-receptor antagonist and it was not affected by phaclofen, a GABA(B)-receptor antagonist. Muscimol, GABA(A) receptor agonist, induced a contractile effect markedly reduced by bicuculline, tetrodotoxin (TTX), hexamethonium and atropine. Cis-4-aminocrotonic acid (CACA), a specific GABA(C) …

Age-related differences of γ-aminobutyric acid (GABA)ergic transmission in human colonic smooth muscle.

2021

Background: Enteric neurons undergo to functional changes during aging. We investigated the possible age-associated differences in enteric γ-aminobutyric acid (GABA)ergic transmission evaluating function and distribution of GABAergic receptors in human colon. Methods: Mechanical responses to GABA and GABA receptor agonists on slow phasic contractions were examined in vitro as changes in isometric tension in colonic muscle strips from young (<65 years old) and aged patients (>65 years old). GABAergic receptor expression was assessed by quantitative RT-PCR. Key Results: In both preparations GABA induced an excitatory effect, consisting in an increase in the basal tone, antagonized by th…

Contractile Reserve and Extent of Transmural Necrosis in the Setting of Myocardial Stunning: Comparison at Cardiac MR Imaging

2010

To perform a comparison of cardiac magnetic resonance (MR) imaging-derived ejection fraction (EF) during low-dose dobutamine infusion (EF(D)) with the extent of segments with transmural necrosis in more than 50% of their wall thickness (ETN) for the prediction of major adverse cardiac events (MACEs) and late systolic recovery soon after a first ST-segment elevation myocardial infarction (STEMI).Institutional ethics committee approval and written informed consent were obtained. One hundred nineteen consecutive patients with a first STEMI, a depressed left ventricular EF, and an open infarct-related artery underwent MR imaging at 1 week after infarction. EF(D) and ETN (by using a 17-segment m…

Neuromuscular mechanics and hopping training in elderly.

2014

Purpose The present study examined the effects of repetitive hopping training on muscle activation profiles and fascicle–tendon interaction in the elderly. Methods 20 physically active elderly men were randomly assigned for training (TG) and control groups (CG). TG performed supervised bilateral short contact hopping training with progressively increasing training volume. Measurements were performed before the training period (BEF) as well as after 2 weeks (2 W) and 11 weeks (11 W) of training. During measurements, the gastrocnemius medialis–muscle (GaM) fascicle and its outer Achilles tendon length changes during hopping were examined by ultrasonography together with electromyographic (EMG…

Akt induces enhanced myocardial contractility and cell size in vivo in transgenic mice

2002

The serine-threonine kinase Akt seems to be central in mediating stimuli from different classes of receptors. In fact, both IGF-1 and IL6-like cytokines induce hypertrophic and antiapoptotic signals in cardiomyocytes through PI3K-dependent Akt activation. More recently, it was shown that Akt is involved also in the hypertrophic and antiapoptotic effects of β-adrenergic stimulation. Thus, to determine the effects of Akt on cardiac function in vivo, we generated a model of cardiac-specific Akt overexpression in mice. Transgenic mice were generated by using the E40K, constitutively active mutant of Akt linked to the rat α-myosin heavy chain promoter. The effects of cardiac-selective Akt overex…