Na+-induced Ca2+ influx through reverse mode of Na+-Ca2+ exchanger in mouse ventricular cardiomyocyte

BACKGROUND: Dobutamine is commonly used for clinical management of heart failure and its pharmacological effects have long been investigated as inotropics via β-receptor activation. However, there is no electrophysiological evidence if dobutamine contributes inotropic action due at least partially to the reverse mode of Na+-Ca2+ exchanger (NCX) activation. METHODS: Action potential (AP), voltage-gated Na+ (INa), Ca2+ (ICa), and K+ (Ito and IK1) currents were observed using whole-cell patch technique before and after dobutamine in ventricular cardiomyocytes isolated from adult mouse hearts. Another sets of observation were also performed with Kb-r7943 or in the solution without [Ca2+]o. RESULTS: Dobutamine (0.1-1.0 μM) significantly enhanced the AP depolarization with prolongation of AP duration (APD) in a concentration-dependent fashion. The density of INa was also increased concentration-dependently without alternation of voltage-dependent steady-status of activation and inactivation, reactivation as well. Whereas, the activities for ICa, Ito, and IK1 were not changed by dobutamine. Intriguingly, the dobutamine-mediated changes in AP repolarization were abolished by 3 μM Kb-r7943 pretreatment or by simply removing [Ca2+]o without affecting accelerated depolarization. Additionally, the ratio of APD50/APD90 was not significantly altered in the presence of dobutamine, implying that effective refractory period was remain unchanged. CONCLUSIONS: This novel finding provides evidence that dobutamine upregulates of voltage-gated Na+ channel function and Na+ influx-induced activation of the reverse mode of NCX, suggesting that dobutamine may not only accelerate ventricular contraction via fast depolarization but also cause Ca2+ influx, which contributes its positive inotropic effect synergistically with β-receptor activation without increasing the arrhythmogenetic risk

Preprocessing the Discrete Time-Cost Tradeoff Problem with Generalized Precedence Relations

This study investigates the deadline of the discrete time-cost tradeoff problem (DTCTP-D) with generalized precedence relations (GPRs). This problem requires modes to be assigned to the activities of a project such that the total cost is minimized and the total completion time and the precedence constraints are satisfied. Anomalies under GPRs are irreconcilable with many current theories and methods. We propose a preprocessing technology, an equivalent simplification approach, which is an effective method for solving large-scale complex problems. We first study a way to deal with the anomalies under GPRs, such as the reduce (increase) in project completion as a consequence of prolonging (shortening) an activity, and discover relationships between time floats and path lengths. Then, based on the theories, we transform the simplification into a time float problem and design a polynomial algorithm. We perform the simplification and improve the efficiency of the solution by deleting redundant calculation objects

Patchy Micelles Based on Coassembly of Block Copolymer Chains and Block Copolymer Brushes on Silica Particles

Patchy particles are a type of colloidal particles with one or more well-defined patches on the surfaces. The patchy particles with multiple compositions and functionalities have found wide applications from the fundamental studies to practical uses. In this research patchy micelles with thiol groups in the patches were prepared based on coassembly of free block copolymer chains and block copolymer brushes on silica particles. Thiol-terminated and cyanoisopropyl-capped polystyrene-<i>block</i>-poly­(<i>N</i>-isopropylacrylamide) block copolymers (PS-<i>b</i>-PNIPAM-SH and PS-<i>b</i>-PNIPAM-CIP) were synthesized by reversible addition–fragmentation chain transfer polymerization and chemical modifications. Pyridyl disulfide-functionalized silica particles (SiO₂-SS-Py) were prepared by four-step surface chemical reactions. PS-<i>b</i>-PNIPAM brushes on silica particles were prepared by thiol–disulfide exchange reaction between PS-<i>b</i>-PNIPAM-SH and SiO₂-SS-Py. Surface micelles on silica particles were prepared by coassembly of PS-<i>b</i>-PNIPAM-CIP and block copolymer brushes. Upon cleavage of the surface micelles from silica particles, patchy micelles with thiol groups in the patches were obtained. Dynamic light scattering, transmission electron microscopy, and zeta-potential measurements demonstrate the preparation of patchy micelles. Gold nanoparticles can be anchored onto the patchy micelles through S–Au bonds, and asymmetric hybrid structures are formed. The thiol groups can be oxidized to disulfides, which results in directional assembly of the patchy micelles. The self-assembly behavior of the patchy micelles was studied experimentally and by computer simulation

Inhibition of transition metals dissolution in cobalt-free cathode with ultrathin robust interphase in concentrated electrolyte

The transition metal dissolution of cathode materials during cycling limits battery performances and lifetimes. Here, authors inhibit metal dissolution by using highly concentrated electrolytes that induce ultra-thin cathode electrolyte interphase formation on cathode surfaces during cycling

Improvement on Cleaning System of SIROX Tobacco Expander

Based on analyzing SIROX the tobacco expander of its pitfalls on cleaning system like poor drainage, valve leakage, cleaning time consuming, etc., this article proposes an improvement of its cleaning system as well as an optimization of its control mode. Furthermore, this article presents a new design of automatic drainage system of the cleaning pipe as well as a real- time monitoring system. This set of system not only addresses quality issues like the over temperature of cylinder wall of the tobacco dryer and the abnormal fluctuation of the tobacco moisture after dryer, but also visualizes the valve leakage thus helps to improve the prompt maintenance of these devices. Observing the two-year operation in HCF, this system proves a high application value

Improvement on Cleaning System of SIROX Tobacco Expander

Based on analyzing SIROX the tobacco expander of its pitfalls on cleaning system like poor drainage, valve leakage, cleaning time consuming, etc., this article proposes an improvement of its cleaning system as well as an optimization of its control mode. Furthermore, this article presents a new design of automatic drainage system of the cleaning pipe as well as a real- time monitoring system. This set of system not only addresses quality issues like the over temperature of cylinder wall of the tobacco dryer and the abnormal fluctuation of the tobacco moisture after dryer, but also visualizes the valve leakage thus helps to improve the prompt maintenance of these devices. Observing the two-year operation in HCF, this system proves a high application value

Excessive gestational weight gain in accordance with the IOM criteria and the risk of hypertensive disorders of pregnancy: a meta-analysis

Abstract Background Excessive gestational weight gain (GWG) is a potential risk factor for hypertensive disorders of pregnancy (HDP). Methods We systematically reviewed three electronic databases for relevant articles published in English: PubMed, EMBASE and Web of Science. The Newcastle-Ottawa Scale was used to assess study quality. Random-effects meta-analyses were performed to supply a pooled estimation of the OR comparing the risk of HDP among healthy pregnant women with and without excessive GWG. Results The pooled estimation for the association between excessive GWG and the risk of HDPs yielded an odds ratio (OR) of 1.79 (95% CI: 1.61–1.99). A subgroup analysis showed that women who had excessive GWG were more likely to have an HDP (OR 1.82; 95% CI 1.53–2.17), preeclampsia (OR 1.92; 95% CI 1.36–2.72), or gestational hypertension (OR 1.67; 95% CI 1.43–1.95). The pooled estimation for the association between excessive GWG and the risk of HDPs among pregestational normal weight women yielded an OR of 1.57 (95% CI 1.26–1.96). A subgroup analysis showed that women who had excessive GWG were more likely to have HDP (OR 1.45; 95% CI 1.09–1.92) or gestational hypertension (OR 1.51; 95% CI 1.22–1.86). The summary ORs of pre-gestational underweight women and pre-gestational overweight and obese women were 2.17 (95% CI 1.56–3.02) and 1.32 (95% CI 1.08–1.63), respectively. Conclusions The findings of this study suggest that excessive GWG in accordance with the IOM recommendations influences the rate of HDP

Quantum Plasmon Engineering with Interacting Graphene Nanoflakes

We investigate the potential merits of using nanometer-sized graphene flakes as building blocks for two-dimensional (2D) quantum metamaterials. The choice of the building blocks of metamaterials is crucial to our ability to design quantum metamaterials with desired properties. In this context, graphene nanostructures are promising candidates to fulfill this role as they can be easily grown either by bottom-up chemical synthesis or top-down electron beam patterning in various shapes, topologies, and sizes, down to the molecular scale. This provides a broad range of parameters to tune the optical properties of graphene-based 2D quantum metamaterials. By using time-dependent density functional theory and quantum chemistry computations, we demonstrate that the graphene-based nanostructures accommodate collective charge oscillations, called quantum plasmons, which are qualitatively different in key aspects from their classical counterparts. In particular, our analysis reveals that the exponents characterizing the power-law scaling of plasmon energy with the size of the graphene flakes are markedly different in the classical and quantum regimes, proving that the quantum plasmons cannot be viewed as a trivial extension of the classical ones to the small-flake limit. In addition, the physical properties of quantum plasmons in graphene nanostructures exhibit significant dependence on their shape and size, and external control can be readily achieved with excess charge. Finally, we find that the energy of the fundamental quantum plasmon mode of triangular nanoflakes is larger than that of hexagonal nanoflakes, whereas in the classical case, the plasmon energy ordering is reversed