Role of phospholamban phosphorylation on Thr17 in cardiac physiological and pathological conditions

The sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a) is under the control of a closely associated SR protein named phospholamban (PLN). Dephosphorylated PLN inhibits the SR Ca2+ pump, whereas phosphorylation of PLN, at either Ser16 by PKA or Thr17 by calmodulin-dependent protein kinase II (CaMKII), reverses this inhibition, thus increasing SERCA2a activity and the rate of Ca2+ uptake by the SR. This would in turn lead to an increase in the velocity of relaxation, SR Ca 2+ load, and myocardial contractility. Thus, PLN is a major determinant of cardiac contractility and relaxation. Although in the intact heart, β-adrenoceptor stimulation results in phosphorylation of PLN at both Ser16 and Thr17 residues, the role of Thr17 site has long remained equivocal. In this review, we attempt to highlight the signaling cascade and the physiological relevance of the phosphorylation of this residue in the heart under both physiological and pathological situations.Facultad de Ciencias Médica

Role of phospholamban phosphorylation on Thr17 in cardiac physiological and pathological conditions

The sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a) is under the control of a closely associated SR protein named phospholamban (PLN). Dephosphorylated PLN inhibits the SR Ca2+ pump, whereas phosphorylation of PLN, at either Ser16 by PKA or Thr17 by calmodulin-dependent protein kinase II (CaMKII), reverses this inhibition, thus increasing SERCA2a activity and the rate of Ca2+ uptake by the SR. This would in turn lead to an increase in the velocity of relaxation, SR Ca 2+ load, and myocardial contractility. Thus, PLN is a major determinant of cardiac contractility and relaxation. Although in the intact heart, β-adrenoceptor stimulation results in phosphorylation of PLN at both Ser16 and Thr17 residues, the role of Thr17 site has long remained equivocal. In this review, we attempt to highlight the signaling cascade and the physiological relevance of the phosphorylation of this residue in the heart under both physiological and pathological situations.Facultad de Ciencias Médica

PT-symmetric coupler with a coupling defect : soliton interaction with exceptional point

We study the interaction of a soliton in a parity-time (PT) symmetric coupler which has local perturbation of the coupling constant. This defect does not change the PT-symmetry of the system, but locally can achieve the exceptional point. We found that the symmetric solitons after interaction with the defect either transform into breathers or blow up. The dynamics of antisymmetric solitons are more complex, showing domains of successive broadening of the beam and of the beam splitting in two outward propagating solitons, in addition to the single breather generation and blowup. All the effects are preserved when the coupling strength in the center of the defect deviates from the exceptional point. If the coupling is strong enough, the only observable outcome of the soliton-defect interaction is the generation of the breather.The work was supported by the Program of Introducing Talents of Discipline to Universities under Grant No. B12024. Y. V. B. and V. V. K. were supported by FCT (Portugal) grants PEst-C/FIS/UI0607/2013, PEst-OE/FIS/UI0618/2011, PTDC/FIS-OPT/1918/2012. C. H. and G. X. H. were supported by the NSF-China grants 11105052 and 11174080

Role of phospholamban phosphorylation on Thr17 in cardiac physiological and pathological conditions

The sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a) is under the control of a closely associated SR protein named phospholamban (PLN). Dephosphorylated PLN inhibits the SR Ca2+ pump, whereas phosphorylation of PLN, at either Ser16 by PKA or Thr17 by calmodulin-dependent protein kinase II (CaMKII), reverses this inhibition, thus increasing SERCA2a activity and the rate of Ca2+ uptake by the SR. This would in turn lead to an increase in the velocity of relaxation, SR Ca 2+ load, and myocardial contractility. Thus, PLN is a major determinant of cardiac contractility and relaxation. Although in the intact heart, β-adrenoceptor stimulation results in phosphorylation of PLN at both Ser16 and Thr17 residues, the role of Thr17 site has long remained equivocal. In this review, we attempt to highlight the signaling cascade and the physiological relevance of the phosphorylation of this residue in the heart under both physiological and pathological situations.Facultad de Ciencias Médica

Taiwan Oscillation Network

The Taiwan Oscillation Network (TON) is a ground-based network to measure solar intensity oscillations to study the internal structure of the Sun. K-line full-disk images of 1000 pixels diameter are taken at a rate of one image per minute. Such data would provide information onp-modes withl as high as 1000. The TON will consist of six identical telescope systems at proper longitudes around the world. Three telescope systems have been installed at Teide Observatory (Tenerife), Huairou Solar Observing Station (near Beijing), and Big Bear Solar Observatory (California). The telescopes at these three sites have been taking data simultaneously since October of 1994. Anl – v diagram derived from 512 images is included to show the quality of the data

Common Problems and Pitfalls in Fluid Inclusion Study: A Review and Discussion

The study of fluid inclusions is important for understanding various geologic processes involving geofluids. However, there are a number of problems that are frequently encountered in the study of fluid inclusions, especially by beginners, and many of these problems are critical for the validity of the fluid inclusion data and their interpretations. This paper discusses some of the most common problems and/or pitfalls, including those related to fluid inclusion petrography, metastability, fluid phase relationships, fluid temperature and pressure calculation and interpretation, bulk fluid inclusion analysis, and data presentation. A total of 16 problems, many of which have been discussed in the literature, are described and analyzed systematically. The causes of the problems, their potential impact on data quality and interpretation, as well as possible remediation or alleviation, are discussed

Linear algorithms for worst case identification in H\u3csup\u3e∞\u3c/sup\u3e with applications to flexible structures

This paper is concerned with linear algorithms for identification in H∞ which have been studied in [9]. It is shown that the two different linear algorithms in [9] can be unified into a single one which can be further extended to nonuniformly spaced frequency response samples with exponential convergence for the noise free case. Improved upper bounds for the corresponding identification errors are derived. Applications to the identification of lightly damped systems such as flexible structures are also considered

From frequency response data to state-space models

This paper considers system identification in frequency domain where the experimental data is a finite set of noisy frequency response measurement samples. The proposed algorithm consists of a combination of identification in H∞ and a modification of Ho/Kung\u27s algorithm to produce state-space models. The associated modeling error in H∞ norm is analyzed based on the a priori information on the unknown true system as well as the level of noise. Upper bounds are derived for the worst-case identification errors. The proposed algorithm is applied to a typical lightly damped system as studied in [8] that yields impressive simulation results

Relationship of exercise capacity and left ventricular dimensions in patients with a normal ejection fraction. An exploratory study.

OBJECTIVES:Extreme endurance exercise is known to be associated with an enlargement of the left ventricular (LV) chamber, whereas inactivity results in inverse changes. It is unknown if these dimensional relationships exist in patients. METHODS:We analyzed the relationship of exercise capacity and LV dimension in a cohort of sequential patients with a normal ejection fraction undergoing stress echocardiography. In a total of 137 studies the following questions were addressed: (a) is there a difference in LV dimensions of patients with an excellent exercise capacity versus patients with a poor exercise capacity, (b) how is LV dimension and exercise capacity affected by LV wall thickness and (c) how do LV dimensions of patients who are unable to walk on a treadmill compare to the above groups. RESULTS:Patients with a poor exercise capacity or who are unable to physically exercise have a 34 percent smaller LV cavity size when compared to patients with an excellent exercise capacity (p<0.001). This reduction in LV chamber size is associated with concentric LV hypertrophy and a reciprocal increase in resting heart rate. In addition, cardiac output reserve is further blunted by chronotropic incompetence and a tachycardia-induced LV volume reduction. In conclusion the relationship of exercise capacity and cardiac dimensions described in extreme athletes also applies to patients. Our exploratory analysis suggests that patients who cannot sufficiently exercise have small LV cavities