This study investigated whether fatiguing dynamic exercise depresses maximal in vitro Na(+)-K(+)-ATPase activity and whether any depression is attenuated with chronic training. Eight untrained (UT), eight resistance-trained (RT), and eight endurance-trained (ET) subjects performed a quadriceps fatigue test, comprising 50 maximal isokinetic contractions (180 degrees /s, 0.5 Hz). Muscle biopsies (vastus lateralis) were taken before and immediately after exercise and were analyzed for maximal in vitro Na(+)-K(+)-ATPase (K(+)-stimulated 3-O-methylfluoroscein phosphatase) activity. Resting samples were analyzed for [(3)H]ouabain binding site content, which was 16.6 and 18.3% higher (P < 0.05) in ET than RT and UT, respectively (UT 311 +/- 41, RT 302 +/- 52, ET 357 +/- 29 pmol/g wet wt). 3-O-methylfluoroscein phosphatase activity was depressed at fatigue by -13.8 +/- 4.1% (P < 0.05), with no differences between groups (UT -13 +/- 4, RT -9 +/- 6, ET -22 +/- 6%). During incremental exercise, ET had a lower ratio of rise in plasma K(+) concentration to work than UT (P < 0.05) and tended (P = 0.09) to be lower than RT (UT 18.5 +/- 2.3, RT 16.2 +/- 2.2, ET 11.8 +/- 0.4 nmol. l(-1). J(-1)). In conclusion, maximal in vitro Na(+)-K(+)-ATPase activity was depressed with fatigue, regardless of training state, suggesting that this may be an important determinant of fatigue.

Ionic regulation is critical to muscle excitation, contraction and metabolism, and thus for muscle function during exercise. This review focuses on the effects of training upon K+, Ca2+ and H+ ion regulation in muscle and K+ regulation in blood during exercise. Training enhances K+ regulation in muscle and blood and reduces muscular fatiguability. Endurance, sprint and strength training in humans induce an increased muscle Na+, K+ pump concentration, usually associated with a reduced rise in plasma [K+] during exercise. Although impaired muscle Ca2+ regulation plays a vital role in fatigue, little is known about possible training effects. In rat fast-twitch muscle, overload-induced hypertrophy and endurance training were associated with reduced sarcoplasmic reticulum Ca2+ uptake, consistent with fast-to-slow fibre transition. In human muscle, endurance and strength training had no effect on muscle Ca2+ ATPase concentration. Whilst muscle Ca2+ uptake, release and Ca2+ ATPase activity were depressed by fatigue, no differences were found between strength athletes and untrained individuals. Muscle H+ accumulation may contribute to fatigue during intense exercise and is also modified by sprint training. Sprint training may increase muscle Lac- and work output with exhaustive exercise, but the rise in muscle [H+] is unchanged or attenuated, indicating a reduced rise in muscle [H+] relative to work performed. Muscle buffering capacity can be dissociated from this improved H+ regulatory capacity after training. Thus, training enhances muscle and blood K+ and muscle H+ regulation during exercise, consistent with improved muscular performance and reduced fatiguability; however, little is known about training effects on muscle Ca2+ regulation during contraction.

BRD4 plays an indispensable role in cell cycle regulation, affecting processes such as cell proliferation, apoptosis and transcription. In this article, a three-dimensional quantitative conformational relationship (3D-QSAR) was used to investigate the molecular simulations related to 45 tetrahydrooxazole BRD4/BD2 selective inhibitors. 3D-QSAR models were developed based on two different analytical methods, COMFA and COMSIA. All CoMSIA field combinations were compared together and the best CoMSIA model was selected based on external validation and model prediction results. Both CoMSIA (S + E + H + D (q 2 = 0.808, r 2 = 0.99)) and CoMFA models (q 2 = 0.779;,r 2 = 0.962) predicted the internal and external well.Twenty small molecules with higher inhibitory activity than the template compound were designed by 3D-QSAR model prediction and quantum chemistry analysis, screened by molecular docking and ADMET methods, and five novel compounds were found to have better predicted activity and binding affinity. Molecular dynamics simulations showed that PRO70, PRO371, TYR428, ASN429 and VAL435 are important residues that can interact with the ligands. Moreover, further structural optimization of the more active candidate compounds will provide an essential theoretical basis of the synthesis and design of novel BRD4/BD2 inhibitors.

The correlation techniques of nodes cooperative transmission strategy in wireless sensor networks with virtual MIMO are presented. A communication model between clusters is proposed. From it, we can see the correlation techniques include coding, forwarding, combining and decoding. The coding is generally divided into three categories: Layered Space-Time Coding, Space-Time Trellis Coding and Space-Time Block Coding. Forwarding can be broken down into Amplifying Forwarding, Decode Forwarding, and Selecting Dynamic Relay. Select combining, equal gain combining and maximum ratio combining are the common combine methods. The decode method is maximum likelihood algorithm.