In order to examine the phenotypic consequences of genetic manipulation in the function of the sinoatrial (SA) node, it is a prerequisite to record the electrical activities of a single pacemaker cell of the SA node of mouse heart. In the present study, we isolated spontaneously beating pacemaker cells from the SA node by enzymatic digestion. The rate of spontaneous action potential firing was 294 ± 59 min−1 at 33–34 °C. The maximal diastolic potential (MDP) was −56.7 ± 7.4 mV and the overshoot was 22.7 ± 6.2 mV. With hyperpolarizing voltage clamp pulses, the hyperpolarization‐activated, cyclic nucleotide‐sensitive cation current (Ih or If) was recorded. Ih started to activate at −70 to ≈−80 mV, more negative than MDP. The half‐maximal activation of Ih was obtained at −107.9 ± 10.4 mV. The inward‐rectifier K+ current (IK1) was also recorded in spontaneously beating myocytes. However, the amplitude of outward IK1 was negligibly small (9.1 ± 3.4 pA at −60 mV). With depolarization, voltage‐gated Na+ current, L‐type Ca2+ current and T‐type Ca2+ current were consistently observed. The sustained inward current (Ist) was also recorded in spontaneously beating pacemaker cells. E4031‐sensitive, rapidly activating delayed rectifier K+ current (IKr) was activated by depolarization, although the amplitude was no more than 38.3 ± 22.2 pA at 0 mV. The chromanol 293B‐sensitive, slowly activating delayed rectifier K+ current (IKs) was not present. The major repolarizing current was the slowly inactivating, 4‐aminopyridine‐insensitive outward current. We concluded that mouse pacemaker cells possess similar membrane currents, including Ist, to those of other species.

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Digital intervention tools against problematic smartphone usage help users control their consumption on smartphones, for example, by setting a time limit on an app. However, today's social media apps offer a mix of quasiessential and addictive features in an app (e.g., Instagram has following feeds, recommended feeds, stories, and direct messaging features), which makes it hard to apply a uniform logic for all uses of an app without a nuanced understanding of feature-level usage behaviors. We study when and why people regret using different features of social media apps on smartphones. We examine regretful feature uses in four smartphone social media apps (Facebook, Instagram, YouTube, and KakaoTalk) by utilizing feature usage logs, ESM surveys on regretful use collected for a week, and retrospective interviews from 29 Android users. In determining whether a feature use is regretful, users considered different types of rewards they obtained from using a certain feature (i.e., social, informational, personal interests, and entertainment) as well as alternative rewards they could have gained had they not used the smartphone (e.g., productivity). Depending on the types of rewards and the way rewards are presented to users, probabilities to regret vary across features of the same app. We highlight three patterns of features with different characteristics that lead to regretful use. First, "following"-based features (e.g., Facebook's News Feed and Instagram's Following Posts and Stories) induce habitual checking and quickly deplete rewards from app use. Second, recommendation-based features situated close to actively used features (e.g., Instagram's Suggested Posts adjacent to Search) cause habitual feature tour and sidetracking from the original intention of app use. Third, recommendation-based features with bite-sized contents (e.g., Facebook's Watch Videos) induce using "just a bit more," making people fall into prolonged use. We discuss implications of our findings for how social media apps and intervention tools can be designed to reduce regretful use and how feature-level usage information can strengthen self-reflection and behavior changes.

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The syntheses of new 2,3-disubstituted 4-chloro-1-hydroxyindoles were described. The conjugate nitro ketoester was reacted with various thiol and alcohol nucleophiles by the action of stannous chloride dihydrate through the unique processes of reduction of nitro group, intramolecular condensation, and addition of nucleophiles in one pot, to provide multisubstituted 1-hydroxyindoles. The reactions with thiol nucleophiles provided better results than those with alcohols, and, in particular, secondary and tertiary thiols provided best yields.

Greenhouse gas (GHG) emissions, which are produced through the combustion of fossil fuels, cause climate change. Unfortunately, South Korea is highly dependent on fossil fuels because of its industrial nature. However, many islands in South Korea have the potential to generate a considerable amount of renewable energy, which should be studied. KEPCO (Korea Electricity Power Corporation), which runs micro-grid facilities in Gasado Island in Jindo, South Korea, built micro-grid facilities in Mozambique in 2015. The micro-grid construction of Gasado Island is considered one of the most successful micro-grid projects of KEPCO, so KEPCO is hoping to expand energy development overseas and become a top-tier global power company. This study aims to find a more technologically and economically optimal hybrid energy system for Gasado Island that KEPCO should have built. We also compared this optimal solution to the Korean government plan. The Korean government plan is the same as the KEPCO plan because KEPCO is classified as a market-oriented public corporation under the Act on the Management of Public Institutions. In the final section of this paper, both the implications and limitations are discussed in detail.

The syntheses of new 3-[(alkylthio)methyl]-1-hydroxy-2-phenylindoles are presented. The substrates, obtained by efficient three-step synthesis, were treated with various thiol nucleophiles in the presence of SnCl2·2H2O to provide target compounds, through the consecutive processes of reduction, condensation, and addition in one pot. The mechanistic studies on reaction pathways and the involved intermediates are described.

BackgroundCoughing is a side effect of opioids that is rarely studied. Here, we evaluated the incidence of remifentanil induced coughing during anesthesia induction in an attempt to identify its risk factors and to examine the preventive effects of lidocaine and salbutamol.MethodsA total of 237 patients scheduled to undergo general anesthesia were allocated randomly into three groups. Group C received no medication, while Group L received 2% lidocaine at 0.5 mg/kg intravenously 1 minute prior to remifentanil infusion and Group S inhaled one metered aerosol puff of salbutamol 15 minutes prior to entering the operating room. Remifentanil was infused at 5 ng/ml by target controlled infusion and coughing was measured for five minutes and graded as none, mild, moderate, or severe based on the number of coughs.ResultsThe incidences of coughing were 30.4%, 25.3%, and 35.4% in Groups C, L, and S, respectively. The incidences, onset times, and severity of coughing did not differ significantly among groups. In addition, multivariate analysis showed that non-smoking and a lower body weight were risk factors of remifentanil-induced coughing (odds ratio, 8.13; P = 0.024, 1.11, and 0.004, respectively).ConclusionsThe incidence of remifentanil-induced coughing was 30%. A total of 0.5 mg/kg lidocaine and 1 metered aerosol puff of salbutamol did not prevent coughing. Non-smoking and low body weight were found to be risk factors of remifentanil-induced coughing.