Mechanical actuators driven by water that respond to multiple stimuli, exhibit fast responses and large deformations, and generate high stress have potential in artificial muscles, motors, and generators. Meeting all these requirements in a single device remains a challenge. We report a graphene monolayer paper that undergoes reversible deformation. Its graphene oxide cells wrinkle and extend i...

In the Etruscan shrew, the isometric twitch contraction times of extensor digitorum longus (EDL) and soleus muscles are shorter than in any other mammal, allowing these muscles to contract at outstandingly high contraction frequencies. This species has the highest mass-specific metabolic rate of all mammals and requires fast skeletal muscles not only for locomotion but also for effective heat p...

We recently reported that masticatory myosin heavy chain (MHC-M) is expressed as the exclusive or predominant MHC isoform in masseter and temporalis muscles of several rodent species, contrary to the prevailing dogma that rodents express almost exclusively MHC isoforms that are typically found in fast limb muscles and not masticatory myosin. We also reported that the same rodent species express...

The isoenzymes carbonic anhydrase II (CAII) and III (CAIII) have been measured by radioimmunoassay in the livers of male and female rats aged from 21 to 800 days. No sexual dimorphism at 21 days was found, but from 50 to 400 days both isoenzymes show sexual differences. From 600 days onwards, these differences are less apparent. CAIII concentrations in two 'fast' fibre muscles and one 'slow' fi...

Background: Spasticity is one of the most important symptoms of stroke, which leads to movement constraints and disability. The presence of spasticity in the ankle and toe plantar flexor muscles disturbs the balance and gait of patients with stroke. Dry needling has been introduced as a new method for the treatment of spasticity. The aim of this study was to investigate the immediate effects of...

OBJECTIVE Mitochondrial function and metabolic profile of slow and fast skeletal muscles and cardiac muscle are altered in chronic heart failure (CHF), suggesting a generalized metabolic myopathy in this disease. The aim of this study was to investigate the potential beneficial effects of voluntary activity on cardiac and skeletal muscle energetics in heart failure. METHODS Heart failure was ...

Depending upon external loading conditions, skeletal muscles can either shorten, lengthen, or remain at a fixed length as they produce force. Fixed-end or isometric contractions stabilize joints and allow muscles to act as active struts during locomotion. Active muscles dissipate energy when they are lengthened by an external force that exceeds their current force producing capacity. These unac...

We investigated the effect of inspiratory resistive breathing (IRB) on the expression of the genes encoding fast and slow isoforms of myosin heavy chain (MyHC) in respiratory muscles. Eleven mongrel dogs were studied for baseline MyHC messenger RNA (mRNA) expression, seven of which were also used to study the effects of IRB. For this latter objective, awake and spontaneously breathing animals w...

[Plate IS] The denervated slow twitch rat soleus muscle was stimulated electrically for 3-6 weeks with brief trains of stimuli a t 100 HZ or long trains a t 10 Hz. I n both cases the mean stimulation frequency was 2 Hz. Muscles stimulated a t 100 Hz acquired several properties characteristic of fast muscle, whereas muscles stimulated a t 10 Hz remained slow. The results demonstrate the importan...

Fiber type specificity for expression of all three rat skeletal muscle pyruvate dehydrogenase kinase (PDK) isoforms (PDK1, 2, and 4) was determined in fed and 24-h fasted rats. PDK activity and isoform protein and mRNA contents were determined in white gastrocnemius (WG; fast-twitch glycolytic), red gastrocnemius (RG; fast-twitch oxidative), and soleus (Sol; slow-twitch oxidative) muscles. PDK ...