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The fast depletion of the petroleum reserves and the rising environmental threats have created an urgent need for sustainable-alternate fuels for the transport and agricultural sectors. In this regard, the ternary blends (diesel–biodiesel-alcohol) have the potential to address the above concerns as they offer huge potential in mitigating exhaust emissions and enhancing engine performance. In the present work, jatropha biodiesel and heptanol have been used as oxygenated additives in the ternary blends in order to save considerable quanta of diesel fuel by restricting its volumetric content to only 40 %. In addition, the fuel injection pressure (IP) is a vital factor that determines the performance and emissions of CI (Compression Ignition) engines. The impact of variations of IP on the performance and emission of CI engine fuelled with ternary blends needs fresh investigation. The previous works lack the analysis of high IP variation in diesel engine fuelled with ternary blend that involve higher alcohol. This experimental work aims to investigate the improvement in CI engine performance and reduction in the exhaust emissions by applying varied IP to the engine powered with diesel-jatropha biodiesel-heptanol blends. In this context, four different ternary blends were prepared by varying biodiesel and heptanol contents from 20 to 50 % and 10–40 %, respectively. The ternary blends were tested in a single-cylinder, four-stroke, direct-injection CI engine by varying the IP from 400 to 500 bar at 10 and 20 Nm engine loads while maintaining the engine speed at 1800 rpm. The results indicated that DBOHep20 achieved a maximum reduction of CO and smoke emissions by 57.4 % and 91.6 %, respectively. The lowest NOx emission was achieved by DBHep40 which was found to be 13.27 % lower than diesel. In the case of engine performance, DBHep40 resulted in lowest BSFC and highest BTE which were found to be just 12.5 % higher and 3.9 % lower than diesel, respectively. The lower IP leads to lesser emissions with a slight compromise with engine performance.

A spectrophotometric study of the system heptanol—Nile red (NR)—water was carried out, where, for the first time for such studies, a non-colloidal surfactant that does not form micelles was taken as a surfactant. The dependence of the solubility of NR on the concentration of heptanol in an aqueous solution was studied. The experiments were carried out at a given chemical potential of NR, which was provided by an excess of the solid phase of NR. The existence of a solubilization effect has been theoretically and experimentally established: An increase in the solubility of NR with an increase in the concentration of heptanol in solution. It was found that heptanol protomicelles with a solubilization core as an NR molecule are formed in such a system, so that in the absence of micelles, the protomicelles take on the entire solubilization load. From the experimental data, the concentration of protomicelle formation was calculated, which can also be taken as the concentration of NR monomerization in an aqueous solution, since the formation of protomicelles prevents the dye aggregation. Based on the results obtained, the following generalizations were made: (1) non-colloidal surfactants, although they do not give micelles, are capable of forming protomicelles; and (2) non-colloidal surfactants can serve as a practical means of dye monomerization. [ABSTRACT FROM AUTHOR]

[Display omitted] The fast depletion of the petroleum reserves and the rising environmental threats have created an urgent need for sustainable-alternate fuels for the transport and agricultural sectors. In this regard, the ternary blends (diesel–biodiesel-alcohol) have the potential to address the above concerns as they offer huge potential in mitigating exhaust emissions and enhancing engine performance. In the present work, jatropha biodiesel and heptanol have been used as oxygenated additives in the ternary blends in order to save considerable quanta of diesel fuel by restricting its volumetric content to only 40 %. In addition, the fuel injection pressure (IP) is a vital factor that determines the performance and emissions of CI (Compression Ignition) engines. The impact of variations of IP on the performance and emission of CI engine fuelled with ternary blends needs fresh investigation. The previous works lack the analysis of high IP variation in diesel engine fuelled with ternary blend that involve higher alcohol. This experimental work aims to investigate the improvement in CI engine performance and reduction in the exhaust emissions by applying varied IP to the engine powered with diesel-jatropha biodiesel-heptanol blends. In this context, four different ternary blends were prepared by varying biodiesel and heptanol contents from 20 to 50 % and 10–40 %, respectively. The ternary blends were tested in a single-cylinder, four-stroke, direct-injection CI engine by varying the IP from 400 to 500 bar at 10 and 20 Nm engine loads while maintaining the engine speed at 1800 rpm. The results indicated that DBOHep20 achieved a maximum reduction of CO and smoke emissions by 57.4 % and 91.6 %, respectively. The lowest NO x emission was achieved by DBHep40 which was found to be 13.27 % lower than diesel. In the case of engine performance, DBHep40 resulted in lowest BSFC and highest BTE which were found to be just 12.5 % higher and 3.9 % lower than diesel, respectively. The lower IP leads to lesser emissions with a slight compromise with engine performance. [ABSTRACT FROM AUTHOR]

In the current experimental study, the synthesis of biodiesel was acquired from mixed pongamia & mahua crude oil (50:50% v/v) with catalyst mixture of 1.5 g K2CO3 in 0.75 g of NH4OH through transesterification method. The effect of diesel, biodiesel, binary blend (B20) and ternary blends of diesel with mixed pongamia & mahua biodiesel and alcohol (ethanol and heptanol) of (B20H10, B20H20, B20E10 and B20E20) fuel samples on CI engine was used to determine engine performance, combustion and emission characteristics at different loading conditions. From the experimental assessment, it was observed that heptanol blended test sample such as (B20H20) has improved thermal efficiency with decreased specific fuel consumption. Furthermore, significant enhancement in prolonged ignition delay causes to generate higher in-cylinder pressure and heat release rate when compared to other binary and ternary samples. The emission parameters like CO, HC and smoke opacity were reduced with slight increase in NOx at operating loads for all tested ternary samples when compared to diesel fuel. Alcohol blended ternary fuel samples caused to reduce CO2 formation according to B20 and B100 fuel but slightly greater than diesel. It is worthwhile to conclude that the prepared B20H20 fuel is a distinguished alternative ternary blend sample preferably than pure biodiesel and binary test sample into CI engine without any engine modification as it satisfies with the diesel performance and to combat global warming. [ABSTRACT FROM AUTHOR]

Cell–cell communication via gap junction channels is known to be inhibited by the anesthetics heptanol, halothane and isoflurane; however, despite numerous studies, the mechanism of gap junction channel gating by anesthetics is still poorly understood. In the early nineties, we reported that gating by anesthetics is strongly potentiated by caffeine and theophylline and inhibited by 4-Aminopyridine. Neither Ca2+ channel blockers nor 3-isobutyl-1-methylxanthine (IBMX), forskolin, CPT-cAMP, 8Br-cGMP, adenosine, phorbol ester or H7 had significant effects on gating by anesthetics. In our publication, we concluded that neither cytosolic Ca2+i nor pHi were involved, and suggested a direct effect of anesthetics on gap junction channel proteins. However, while a direct effect cannot be excluded, based on the potentiating effect of caffeine and theophylline added to anesthetics and data published over the past three decades, we are now reconsidering our earlier interpretation and propose an alternative hypothesis that uncoupling by heptanol, halothane and isoflurane may actually result from a rise in cytosolic Ca2+ concentration ([Ca2+]i) and consequential activation of calmodulin linked to gap junction proteins. [ABSTRACT FROM AUTHOR]

We prepared films of 4-methyl-3-heptanol by vapor depositing onto substrates held at temperatures between Tdep = 0.6Tg and Tg, where Tg is the glass transition temperature. Using deposition rates between 0.9 and 6.0 nm/s, we prepared films about 5 µm thick and measured the dielectric properties via an interdigitated electrode cell onto which films were deposited. Samples prepared at Tdep = Tg display the dielectric behavior of the ordinary supercooled liquid. Films deposited at lower deposition temperatures show a high dielectric loss upon heating toward Tg, which decreases by a factor of about 12 by annealing at Tg = 162 K. This change is consistent with either a drop of the Kirkwood correlation factor, gk, by a factor of about 10, or an increase in the dielectric relaxation times, both being indicative of changes toward ring-like hydrogen-bonded structure characteristic of the ordinary liquid. We rationalize the high dielectric relaxation amplitude in the vapor deposited glass by suggesting that depositions at low temperature provide insufficient time for molecules to form ring-like supramolecular structures for which dipole moments cancel. Surprisingly, above Tg of the ordinary liquid, these vapor deposited films fail to completely recover the dielectric properties of the liquid obtained by supercooling. Instead, the dielectric relaxation remains slower and its amplitude much higher than that of the equilibrium liquid state, indicative of a structure that differs from the equilibrium liquid up to at least Tg + 40 K. [ABSTRACT FROM AUTHOR]

Background: Previous studies have associated slowed ventricular conduction with the arrhythmogenesis mediated by the gap junction and sodium channel inhibitor heptanol in mouse hearts. However, they did not study the propagation patterns that might contribute to the arrhythmic substrate. This study used a multi-electrode array mapping technique to further investigate different conduction abnormalities in Langendorff-perfused mouse hearts exposed to 0.1 or 2 mM heptanol. Methods: Recordings were made from the left ventricular epicardium using multi-electrode arrays in spontaneously beating hearts during right ventricular 8 Hz pacing or S1S2 pacing. Results: In spontaneously beating hearts, heptanol at 0.1 and 2 mM significantly reduced the heart rate from 314 ± 25 to 189 ± 24 and 157 ± 7 bpm, respectively (ANOVA, p < 0.05 and p < 0.001). During regular 8 Hz pacing, the mean LATs were increased by 0.1 and 2 mM heptanol from 7.1 ± 2.2 ms to 19.9 ± 5.0 ms (p < 0.05) and 18.4 ± 5.7 ms (p < 0.05). The standard deviation of the mean LATs was increased from 2.5 ± 0.8 ms to 10.3 ± 4.0 ms and 8.0 ± 2.5 ms (p < 0.05), and the median of phase differences was increased from 1.7 ± 1.1 ms to 13.9 ± 7.8 ms and 12.1 ± 5.0 ms by 0.1 and 2 mM heptanol (p < 0.05). P5 took a value of 0.2 ± 0.1 ms and was not significantly altered by heptanol at 0.1 or 2 mM (1.1 ± 0.9 ms and 0.9 ± 0.5 ms, p > 0.05). P50 was increased from 7.3 ± 2.7 ms to 24.0 ± 12.0 ms by 0.1 mM heptanol and then to 22.5 ± 7.5 ms by 2 mM heptanol (p < 0.05). P95 was increased from 1.7 ± 1.1 ms to 13.9 ± 7.8 ms by 0.1 mM heptanol and to 12.1 ± 5.0 ms by 2 mM heptanol (p < 0.05). These changes led to increases in the absolute inhomogeneity in conduction (P5–95) from 7.1 ± 2.6 ms to 31.4 ± 11.3 ms, 2 mM: 21.6 ± 7.2 ms, respectively (p < 0.05). The inhomogeneity index (P5–95/P50) was significantly reduced from 3.7 ± 1.2 to 3.1 ± 0.8 by 0.1 mM and then to 3.3 ± 0.9 by 2 mM heptanol (p < 0.05). Conclusion: Increased activation latencies, reduced CVs, and the increased inhomogeneity index of conduction were associated with both spontaneous and induced ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

The localization of many membrane proteins within cholesterol- and sphingolipid-containing microdomains is essential for proper cell signaling and function. These membrane domains, however, are too small and dynamic to be recorded, even with modern super-resolution techniques. Therefore, the association of membrane proteins with these domains can only be detected with biochemical assays that destroy the integrity of cells require pooling of many cells and take a long time to perform. Here, we present a simple membrane fluidizer–induced clustering approach to identify the phase-preference of membrane-associated molecules in individual live cells within 10–15 min. Experiments in phase-separated bilayers and live cells on molecules with known phase preference show that heptanol hyperfluidizes the membrane and stabilizes phase separation. This results in a transition from nanosized to micronsized clusters of associated molecules allowing their identification using routine microscopy techniques. Membrane fluidizer-induced clustering is an inexpensive and easy to implement method that can be conducted at large-scale and allows easy identification of protein partitioning in live cell membranes.

Highly unusual linear-response spectra involving contributions from hydrogen-bonded supramolecular processes and from structural relaxations are found in 4-methyl-3-heptanol mixed with 2-ethyl-1-hexylbromide. Although the mean time scales of the underlying relaxations are separated by more than 3 decades, the overall spectra cannot be decomposed into a sum of these processes. This finding challenges the ubiquitous practice of disentangling susceptibility spectra of Debye liquids by adding suitable subspectra. The spectral shape of the studied viscous mixtures is excellently described using the Williams ansatz, here a necessary approach and not as previously considered merely an alternative to additive analyses. [ABSTRACT FROM AUTHOR]

A spectrophotometric study of the system heptanol—Nile red (NR)—water was carried out, where, for the first time for such studies, a non-colloidal surfactant that does not form micelles was taken as a surfactant. The dependence of the solubility of NR on the concentration of heptanol in an aqueous solution was studied. The experiments were carried out at a given chemical potential of NR, which was provided by an excess of the solid phase of NR. The existence of a solubilization effect has been theoretically and experimentally established: An increase in the solubility of NR with an increase in the concentration of heptanol in solution. It was found that heptanol protomicelles with a solubilization core as an NR molecule are formed in such a system, so that in the absence of micelles, the protomicelles take on the entire solubilization load. From the experimental data, the concentration of protomicelle formation was calculated, which can also be taken as the concentration of NR monomerization in an aqueous solution, since the formation of protomicelles prevents the dye aggregation. Based on the results obtained, the following generalizations were made: (1) non-colloidal surfactants, although they do not give micelles, are capable of forming protomicelles; and (2) non-colloidal surfactants can serve as a practical means of dye monomerization.

Background: Time-domain and non-linear methods can be used to quantify beat-to-beat repolarization variability but whether measures of repolarization variability can predict ventricular arrhythmogenesis in mice have never been explored. Methods: Left ventricular monophasic action potentials (MAPs) were recorded during constant right ventricular 8 ​Hz pacing in Langendorff-perfused mouse hearts, in the presence or absence of the gap junction and sodium channel inhibitor heptanol (0.1, 0.5, 1 or 2 ​mM). Results: Under control conditions, mean action potential duration (APD) was 39.4 ​± ​8.1 ​ms. Standard deviation (SD) of APDs was 0.3 ​± ​0.2 ​ms, coefficient of variation was 0.9 ​± ​0.8% and the root mean square (RMS) of successive differences in APDs was 0.15 ​± ​0.14 ​ms. Poincaré plots of APDn+1 against APDn revealed ellipsoid morphologies with a SD along the line-of-identity (SD2) to SD perpendicular to the line-of-identity (SD1) ratio of 4.6 ​± ​2.1. Approximate and sample entropy were 0.61 ​± ​0.12 and 0.76 ​± ​0.26, respectively. Detrended fluctuation analysis revealed short- and long-term fluctuation slopes of 1.49 ​± ​0.27 and 0.81 ​± ​0.36, respectively. Heptanol at 2 ​mM induced ventricular tachycardia in five out of six hearts. None of the above parameters were altered by heptanol during which reproducible electrical activity was observed (KW-ANOVA, P ​> ​0.05). Contrastingly, SD2/SD1 decreased to 2.03 ​± ​0.41, approximate and sample entropy increased to 0.82 ​± ​0.12 and 1.45 ​± ​0.34, and short-term fluctuation slope decreased to 0.82 ​± ​0.19 during the 20-s period preceding spontaneous ventricular tachy-arrhythmias (n ​= ​6, KW-ANOVA, P ​

Studies on the usage of gasoline–alcohol blends as an alternative fuel in spark-ignition engines have recently gained momentum. In the present research, energy, exergy, environmental, enviroeconomic, exergoenvironmental, and exergoenviroeconomic analyses were conducted with the performance and emission values acquired by utilizing gasoline, gasoline–heptanol, and gasoline–hexanol fuels (G100, HEX5-20, and HP5-20) as a fuel under different powers at a constant speed of 1600 rpm in a single-cylinder four-stroke spark-ignition engine. As the ratio of alcohol in fuel blends increases, fuel consumption also increases. NOX emission is higher, and CO and HC emissions are lower in alcohol-based fuel blends than G100 fuel. The highest thermal efficiency is 41.09% in G100 fuel at a power of 5 kW. As the ratio of alcohol in fuel blends increases, thermal efficiency decreases. The highest exergy destruction and entropy generation were determined to be 6.25 kW and 0.02134 kW/K, respectively, in HP20 fuel at a power of 5 kW. Entropy generation increases with an increase in the ratio of alcohol in alcohol-based fuels. HEX20 and HP20 fuels produce 25% and 30% more entropy, respectively, compared to G100 fuel. The mass and financial costs of the damage caused by the CO2 emission of fuels to the environment were determined by conducting four different analyses using energy and exergy analysis data. According to the exergoenvironmental and exergoenviroeconomic analyses, HP20 fuel reached the highest environmental pollution values of 4538.19 kg CO2/month and 65.804 $/month, respectively. The environmental cost of the CO2 emission released from the exhaust to the atmosphere is higher in alcohol-based fuels than G100 fuel. As a result of all analyses, it was concluded that hexanol and heptanol could be alternative fuels in spark-ignition engines under particular conditions. [ABSTRACT FROM AUTHOR]

Using non-linear dielectric techniques, we have measured the dynamics of 5-methyl-3-heptanol at a temperature at which the Kirkwood correlation factor gK indicates the coexistence of ring- and chainlike hydrogen-bonded structures. Steady state permittivity spectra recorded in the presence of a high dc bias electric field (17 MV/m) reveal that both the amplitude and the time constant are increased by about 10% relative to the low field limit. This change is attributed to the field driven conversion from ring-like to the more polar chain-like structures, and a direct observation of its time dependence shows that the ring/chain structural transition occurs on a time scale that closely matches that of the dielectric Debye peak. This lends strong support to the picture that places fluctuations of the end-to-end vector of hydrogen bonded structures at the origin of the Debye process, equivalent to fluctuations of the net dipole moment or gK. Recognizing that changes in the ring/chain equilibrium constant also impact the spectral separation between Debye and a-process may explain the difference in their temperature dependence whenever gK is sensitive to temperature, i.e., when the structural motifs of hydrogen bonding change considerably. [ABSTRACT FROM AUTHOR]

Cell–cell communication via gap junction channels is known to be inhibited by the anesthetics heptanol, halothane and isoflurane; however, despite numerous studies, the mechanism of gap junction channel gating by anesthetics is still poorly understood. In the early nineties, we reported that gating by anesthetics is strongly potentiated by caffeine and theophylline and inhibited by 4-Aminopyridine. Neither Ca2+ channel blockers nor 3-isobutyl-1-methylxanthine (IBMX), forskolin, CPT-cAMP, 8Br-cGMP, adenosine, phorbol ester or H7 had significant effects on gating by anesthetics. In our publication, we concluded that neither cytosolic Ca2+i nor pHi were involved, and suggested a direct effect of anesthetics on gap junction channel proteins. However, while a direct effect cannot be excluded, based on the potentiating effect of caffeine and theophylline added to anesthetics and data published over the past three decades, we are now reconsidering our earlier interpretation and propose an alternative hypothesis that uncoupling by heptanol, halothane and isoflurane may actually result from a rise in cytosolic Ca2+ concentration ([Ca2+]i) and consequential activation of calmodulin linked to gap junction proteins.

Background: Rice dwarf virus (RDV)-induced rice plant volatiles (E)-β-caryophyllene and 2-heptanol modulate the olfactory behavior of RDV insect vectors that promote viral acquisition and transmission. However, it remains elusive whether these two volatiles could influence the behaviors of the natural enemies of RDV insect vectors. Herein, we determined the effects of these two volatiles on the olfactory and predatory behaviors of Cyrtorhinus lividipennis (Hemiptera: Miridae), an important predator of RDV insect vectors in rice paddies., Results: The results showed that C. lividipennis preferred RDV-infected rice plant odors over RDV-free rice plant odors. C. lividipennis was attracted by (E)-β-caryophyllene, but showed no behavioral responses to 2-heptanol. The attraction of (E)-β-caryophyllene towards C. lividipennis was further confirmed using oscas1 rice plants, which do not release (E)-β-caryophyllene in response to RDV infection, through a series of complementary assays. The oviposition preference of the RDV vector insect Nephotettix cincticeps (Hemiptera: Cicadellidae) showed no significant difference between RDV-infected and RDV-free wild-type plants, nor between oscas1-RDV and oscas1 plants. However, the predation rate of C. lividipennis for N. cincticeps eggs on RDV-infected plants was higher than that on RDV-free plants, whereas there was no significant difference between oscas1-RDV and oscas1 plants., Conclusion: (E)-β-caryophyllene induced by RDV attracted more C. lividipennis to prey on N. cincticeps eggs and played a crucial role in plant-virus-vector-enemy interactions. These novel findings will promote the design of new strategies for disease control by controlling the populations of insect vectors, for example recruiting more natural enemies by virus-induced plant volatiles. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Aims Treatment of arrhythmias evoked by hypothermia/rewarming remains challenging, and the underlying mechanisms are unclear. This in vitro experimental study assessed cardiac electrophysiology in isolated rabbit hearts at temperatures occurring in therapeutic and accidental hypothermia. Methods and results Detailed ECG, surface electrogram, and panoramic optical mapping were performed in isolated rabbit hearts cooled to moderate (31°C) and severe (17°C) hypothermia. Ventricular activation was unchanged at 31°C while action potential duration (APD) was significantly prolonged (176.9 ± 4.2 ms vs. 241.0 ± 2.9 ms, P  < 0.05), as was ventricular repolarization. At 17°C, there were proportionally similar delays in both activation and repolarization. These changes were reflected in the QRS and QT intervals of ECG recordings. Ventricular fibrillation threshold was significantly reduced at 31°C (16.3 ± 3.1 vs. 35 ± 3.5 mA, P  < 0.05) but increased at 17°C (64.2 ± 9.9, P  < 0.05). At 31°C, transverse conduction was relatively unchanged by cooling compared to longitudinal conduction, but at 17°C both transverse and longitudinal conduction were proportionately reduced to a similar extent. The gap junction uncoupler heptanol had a larger relative effect on transverse than longitudinal conduction and was able to restore the transverse/longitudinal conduction ratio, returning ventricular fibrillation threshold to baseline values (16.3 ± 3.1 vs. 36.3 ± 4.3 mA, P  < 0.05) at 31°C. Rewarming to 37°C restored the majority of the electrophysiological parameters. Conclusions Moderate hypothermia does not significantly change ventricular conduction time but prolongs repolarization and is pro-arrhythmic. Further cooling to severe hypothermia causes parallel changes in ventricular activation and repolarization, changes which are anti-arrhythmic. Therefore, relative changes in QRS and QT intervals (QR/QTc) emerge as an ECG-biomarker of pro-arrhythmic activity. Risk for ventricular fibrillation appears to be linked to the relatively low temperature sensitivity of ventricular transmural conduction, a conclusion supported by the anti-arrhythmic effect of heptanol at 31°C. [ABSTRACT FROM AUTHOR]

4-methyl-3-heptanol, a monohydroxy alcohol with a relatively small dielectric Debye process, is studied in wide ranges of temperature (143 K < T < 308 K) and pressure (0.1 MPa < p < 864 MPa). When monitored under isochronous conditions, i.e., focusing on constant relaxation times, as well as under isothermal conditions, the Debye process gains significant intensity upon pressure application. This behavior contrasts with that of the previously studied octanol 2-ethyl-1-hexanol, which features a large Debye process. These experimentally observed, clearly distinguishable pressure evolutions are discussed to reflect differences in the formation of hydrogen-bonded supramolecular structures. [ABSTRACT FROM AUTHOR]

Highlights • New experimental density data for binary mixtures of dibuthyl ether (DBE) + 1-heptanol. • Excess volumes have been calculated from the experimental data. • The isobaric thermal expansivity have been derived from the Tait-like equation. • The isothermal compressibility have been derived from the Tait-like equation. • PC-SAFT parameters of this mixture were optimized using density data. Abstract This work reports new experimental density data (816 points) for binary mixtures of dibutyl ether (DBE) + 1-heptanol over the composition range (5 compositions; 0.15 ≤ dibutyl ether mole fraction x ≤ 0.85), between 298.15 and 393.15 K, and for 23 pressures from 0.1 MPa up to 140 MPa. An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.7 kg·m−3 was used to perform these measurements. The experimental density data were fitted with a Tait-like equation with low standard deviations. Excess volumes have been calculated from the experimental data. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation, provided as supplementary material. In addition, PC-SAFT parameters of DBE and 1-heptanol were optimized using density data at atmospheric pressure. From PC-SAFT, density of mixture was reasonably well predicted with an average relative deviation varied between 0.00015% and 2.80%. [ABSTRACT FROM AUTHOR]

A supramolecular solvent microextraction method was used for the fast and selective preconcentration separation of malathion, and then ultra-performance liquid chromatography-tandem mass spectrometry was applied for the detection of malathion. The supramolecular solvent is a suitable medium for malathion collection from the sample extract. The results showed that the quantitative recovery of malathion was obtained at pH 4 with heptanol-tetrahydrofuran as the supramolecular solvent. The preconcentration of malathion by the developed microextraction method was established within 10 min. The limit of detection and the quantification limit were 1.4 and 4.2 µg/L, respectively. A preconcentration factor of 40 was obtained, and the relative standard deviation was <7%. The developed supramolecular solvent microextraction method was applied for different real samples, including fruits, vegetables, and water samples. [ABSTRACT FROM AUTHOR]

Highlights • endo-1,2,3,3-Tetramethylbicyclo[2.2.1]heptan-2-ol, safety assessment based on RIFM's criteria. • Safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC. [ABSTRACT FROM AUTHOR]

Highlights • The combining of label-free cell phenotypic assay with 2DLC. • D1 activity location and D2 activity tracking obtained three β 2 -AR agonists. • The first time to discover diarylheptanoids with the β 2 -AR agonistic activity. • Providing possible explanation for the anti-asthmatic effect of C. zedoaria. Abstract Traditional Chinese Medicines (TCMs) have been widely used in clinical practice, and provided a rich source for discovering new drug leads. However, efficient identification of active molecules responsible for the therapeutic effects of complex TCMs is still highly challenging. Here, we combined label-free cell phenotypic assay with two dimensional liquid chromatography (2DLC) to identify potential β 2 -adrenoceptor (β 2 -AR) agonists related to anti-asthmatic effect of Curcuma zedoaria Rosc (C.zedoaria), a commonly used TCM. The ethyl acetate extract of C.zedoaria was first fractionated into 26 fractions. Label-free cell phenotypic profiling was then used to locate the active sites. Orthogonal second-dimensional (D2) separation was performed on two fractions displaying agonistic effect at the β 2 -AR, combined with screening of the D2 fractions to track the activity. Finally, this approach led to the isolation of three known diarylheptanoids, among which diarylheptanoid b exhibited the most potent agonistic activity with an EC 50 value of 5.93 μM. This result was further demonstrated through the chemical synthesis of diarylheptanoid b. It is the first time to discover that diarylheptanoids could activate the β 2 -AR, which may be responsible for the anti-asthmatic effect of C.zedoaria observed traditionally and in clinical application. This study also demonstrates the potential of this integrated strategy for identifying active ingredients and determining the basis of therapeutic materials in complex TCMs. [ABSTRACT FROM AUTHOR]

Signal transduction by the high-affinity IgE receptor (FcεRI) depends on membrane lipid and protein compartmentalization. Recently published data show that cells treated with 1-heptanol, a cell membrane fluidizer, exhibit changes in membrane properties. However, the functional consequences of 1-heptanol-induced changes on mast cell signaling are unknown. This study shows that short-term exposure to 1-heptanol reduces membrane thermal stability and dysregulates mast cell signaling at multiple levels. Cells treated with 1-heptanol exhibited increased lateral mobility and decreased internalization of the FcεRI. However, this did not affect the initial phosphorylation of the FcεRI-β chain and components of the SYK/LAT1/PLCγ1 signaling pathway after antigen activation. In contrast, 1-heptanol inhibited SAPK/JNK phosphorylation and effector functions such as calcium response, degranulation, and cytokine production. Membrane hyperfluidization induced a heat shock-like response via increased expression of the heat shock protein 70, increased lateral diffusion of ORAI1-mCherry, and unsatisfactory performance of STIM1-ORAI1 coupling, as determined by flow-FRET. Furthermore, 1-heptanol inhibited the antigen-induced production of reactive oxygen species and potentiated stress-induced plasma membrane permeability by interfering with heat shock protein 70 activity. The combined data suggest that 1-heptanol-mediated membrane fluidization does not interfere with the earliest biochemical steps of FcεRI signaling, such as phosphorylation of the FcεRI-β chain and components of the SYK/LAT/PLCγ1 signaling pathway, instead inhibiting the FcεRI internalization and mast cell effector functions, including degranulation and cytokine production.

Fe-Ni alloy nanoparticles were synthesized by polyol process using hydrazine as a reduction assist reagent. Particle size, crystallite size, and crystal phases varied with the type of polyol. The saturation magnetizations of the as-synthesized Fe-Ni particles synthesized in ethylene glycol (EG) and 1-heptanol were similar to the bulk and were 73 emu/g and 83 emu/g, respectively. On the other hand, the coercivities of the same were 41 and 123 Oe. The coercivity of the Fe-Ni particles synthesized in EG decreased to 27 Oe after heat treatment. Though the magnetic properties were very similar irrespective of the polyol used in this study, the Mössbauer spectroscopic measurements revealed that Fe-Ni particles with single permalloy phase was synthesized only when EG was used. [ABSTRACT FROM AUTHOR]

In this work, the action of heptanol and ethanol was investigated in a two-dimensional (2D) model of cardiac tissue: the neonatal rat ventricular myocyte monolayer. Heptanol is known in electrophysiology as a gap junction uncoupler but may also inhibit voltage-gated ionic channels. Ethanol is often associated with the occurrence of arrhythmias. These substances influence sodium, calcium, and potassium channels, but the complete mechanism of action of heptanol and ethanol remains unknown. The optical mapping method was used to measure conduction velocities (CVs) in concentrations of 0.05–1.8 mM heptanol and 17–1342 mM ethanol. Heptanol was shown to slow the excitation wave significantly, and a mechanism that involves a simultaneous action on cell coupling and activation threshold was suggested. Whole-cell patch-clamp experiments showed inhibition of sodium and calcium currents at a concentration of 0.5 mM heptanol. Computer modeling was used to estimate the relative contribution of the cell uncoupling and activation threshold increase caused by heptanol. Unlike heptanol, ethanol slightly influenced the CV at clinically relevant concentrations. Additionally, the critical concentrations for re-entry formation in ethanol were determined. [ABSTRACT FROM AUTHOR]

The experimental liquid-liquid equilibrium (LLE) data of the quaternary systems ethanol + hexanol + decane + water, ethanol + hexanol + undecane + water, ethanol + heptanol + decane + water, and ethanol + heptanol + undecane + water were collected at 298.15 K under atmospheric pressure. The UNIQUAC model was used to regress the quaternary systems and acquire the binary interaction parameter, which was used to predict the LLE data of the six-component system. The predicted LLE data were compared with the experimental data, and the results showed they were in good agreement, which indicated that the binary interaction parameters acquired from the quaternary systems could predict the LLE data of the six-component system. The distribution coefficient and the selectivity showed that 65% ethanol aqueous solution was suitable for separating hexanol and heptanol from the hexanol-heptanol-decane-undecane mixture. [ABSTRACT FROM AUTHOR]

Several studies have shown that lipid oxidation can occur in topical skin formulations, but the impact of the individual volatile compounds on off‐odour has not yet been determined. In this study, lipid oxidation is investigated in prototype skin care formulations. Firstly, lipid oxidation volatile compounds that increased in concentration during storage are identified. The results show that the concentration of six volatile compounds increased above previously reported odour detection threshold values in water. These volatile compounds are selected for odour detection threshold value determination and also odour description by a trained sensory panel. In one case, the odour detection threshold value is 50 times higher (less detectable) in skin care products than in water, whereas for other volatile compounds the odour detection threshold value is only 1.5 times higher. The odour description of the volatile compounds is, in most cases, different from that reported in literature. The observed differences are hypothesised to be due to a masking effect of the base odour of the skin care product(s), a volatile‐retaining power of the base matrix and to a cocktail effect of the combined odours from different volatile oxidation products. Practical Application: In this study, the impact of volatile compounds on off‐odour is explored in prototype skin care formulations. The odour detection threshold value and odour description are determined for butanal, pentanal, 3‐methyl‐1‐butanol, 2‐ethyl furan, 2‐pentyl furan and 1‐heptanol in prototype skin care formulations. Overview of the different odour descriptors of the same volatile (3‐methyl‐1‐butanol) when found in topical skin formulations with different lipid contents. [ABSTRACT FROM AUTHOR]

In this paper, the modeling of holes in the critical surface and miscibility windows, in the ternary carbon dioxide + 1-hexanol + n-pentadecane and carbon dioxide + 1-heptanol + n-pentadecane systems, was made. A software for phase equilibrium (PHEQ) data management and applications was used for calculations with the cubic general equation of state (GEOS), developed by the author. The software PHEQ was extended for calculations of critical lines (module GEOS CRITHK), using the Heidemann and Khalil method, and liquid-liquid-vapor (llg) lines (module GEOS LLVE) in binary and ternary mixtures. These modules were used for the calculation of holes in critical surfaces, and of miscibility windows. Binary and quasi-binary measured phase equilibrium data by Scheidgen [Ph.D. Thesis, Ruhr-Universität Bochum, 1997] were necessary for understanding and modeling of ternary systems, regarding holes in critical surface and miscibility windows. For modeling, the equation of state Soave-Redlich-Kwong, integrated in the cubic GEOS form, coupled with the two-parameters conventional mixing rule was used. A simple semipredictive approach was adopted for the estimation of the two binary interaction parameters by a trial and error procedure for reproducing the temperature and pressure values of the two experimental double critical end points (DCEPs). A unique set of parameters obtained by this procedure was used to predict the critical and three phases llg lines for all quasi-binary systems at reduced mass fractions of n-pentadecane in the range between the two experimental DCEPs. The calculated holes in the critical surface and miscibility windows are in satisfactory agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

This paper reports the results of an experimental investigation of heat transfer from a wickless finned heat pipe charged with different self-rewetting fluids. The geometry considered for the experiments comprises an evaporator section of length 200 mm, condenser section of length 200 mm and adiabatic section of length 100 mm. Six constant area fins are placed internally along the length of the condenser. The width of the fin is 5 mm and the thickness is 1 mm. Adding internal fins at the condenser wall gives more surface area to the vapor for heat transfer. This gives additional condensation that keeps the evaporator at safe temperatures and extends the dry out condition. Additionally, fins break the condensed liquid film and augment heat transfer. The fill ratio considered in the present study is 50 % . The self rewetting fluids considered in this work are butanol, pentanol, hexanol, and heptanol aqueous solutions. The concentrations of the self rewetting fluids are changed to study the thermal behavior of a heat pipe and the results are compared with those for water charged devices presented in literature. The thermosyphon is tested between power levels of 150 W (heat flux = 9182 W/ m 2 ) and 350 W (heat flux = 21424 W/ m 2 ). Results confirm superior thermal performance of self rewetting fluids compared to water. [ABSTRACT FROM AUTHOR]

Liquid phase catalytic coupling of n-pentanol over VIII group metals (Pt, Pd, Ir, Ru, Rh) on a range of supports (C, Al2O3, TiO2, CeO2, ZrO2) doped with different solid bases was done varying the reaction temperature and gas atmosphere. It was shown that n-pentanol coupling in the selected reaction conditions (180 °C, 10 bar of N2) mainly resulted in the formation of the target product 2-propyl-1-heptanol (Guerbet alcohol), whereas pentanal, 2-propyl-2-heptenal, 2-propyl-1-heptanal, and 2-propyl-1-heptenol were observed in minor quantities. Temperature increase accelerates the reaction and improves selectivity to 2-propyl-1-heptanol. Acid-base properties of the supports also influenced conversion and selectivity correlating with the support base strength TiO2 (860 kJ/mol) < ZrO2 (900 kJ/mol) < C (850-910 kJ/mol) < Al2O3 (935 kJ/mol). For carbon supported catalysts conversion increases in the raw Ir < Ru < Pt < Pd. Analysis of the reaction mechanism for NaOH/Pt/Al2O3 and the relative contributions of various catalytically active phases was done by in situ Fourier transform infrared spectroscopy. [ABSTRACT FROM AUTHOR]

Hydrolysis is the prevalent mechanism of decomposition of benzo- and caprinohydroxamic acids (HAs) in nitric and perchloric acid solutions and in the equilibrium organic phase based on heptanol, decanol, and 30% TBP in С13 paraffin diluent. In the nitric acid system with alcohols, HAs undergo autocatalytic oxidation at temperatures raised over 50°С. In the case of BHA, the process occurs in both phases taken separately and on their mixing. In the case of caprinohydroxamic acid poorly soluble in HNO solutions, the autocatalytic process occurs only at 70-80°С on mixing the phases; it tends to fade as the phase ratio n = О/A is increased from 1 to 10. This trend determines the conditions for Mo stripping in this system. In the practice of the Mo production, the stripping efficiency can be increased by repeated contact with the addition of non-salt complexing agents (HO, HCO, CHCONHOH) into the system. [ABSTRACT FROM AUTHOR]

Abstract Background The potential attraction from 1-octen-3-ol for sandflies has been documented; however, studies using other primary alcohols are limited. Findings We used a wind tunnel to compare the activation and attractive behaviors in male and female Lutzomyia longipalpis using 1-octen-3-ol and three additional alcohols, 1-octanol, 1-heptanol and 1-nonanol at three different concentrations: neat (100%) and diluted in hexane (10% and 50%). The compounds 1-octen-3-ol and 1-nonanol induced a clear concentration-dependent activation and attraction response in females. In males, 1-octen-3-ol, 1-nonanol and 1-heptanol yielded the same results. Conclusions L. longipalpis is attracted to 1-octen-3-ol, 1-nonanol and 1-heptanol, which are found in many plant volatiles.

Three pure heptanol isomers were studied using infrared spectroscopy: n -heptanol, 2,4-dimethyl-3-pentanol, and 3-ethyl-3-pentanol. In order to analyze the branching effect of heptanol, investigations on the two symmetric branched isomers have been performed. Branching and steric hindrance highly influence the aggregation in associating systems. Therefore, a systematic comparison with the linear molecule n -heptanol is performed to better understand the experimental data. The vibrational structures were studied in the spectral range from 650 to 4000 cm − 1 and the individual peaks were assigned to the corresponding vibrational modes of the molecules. The OH-stretching band is significantly narrower in the spectra of the branched alcohols compared to n -heptanol. In particular, the low frequency components of the band are absent. This is a result of the steric hindrance leading to a less pronounced hydrogen bonding network. [ABSTRACT FROM AUTHOR]

Fermentation of Alnus sibirica (AS) stems using Lactobacillus plantarum subsp. argentoratensis was conducted and three compounds isolated from the Alnus species were identified for the first time, 7-(3,4-dihydroxyphenyl)-1-(4-hydroxyphenyl)-heptan-3-one, 1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptan-3-one and 4-(3,4-dihydroxyphenyl)-butan-2-one, along with 14 known compounds. The anti-oxidative and anti-inflammatory abilities of AS and fermented AS (FAS) as well as the isolated phenolic compounds from FAS were investigated. FAS showed stronger anti-oxidative and anti-inflammatory activities than non-fermented AS. [ABSTRACT FROM AUTHOR]

In this work, the sophisticated thermodynamic techniques: thermodynamic and thermophysical properties of binary mixtures of 1-ethyl-3-methylimidazolium [C 2 mim][MeSO 4 ] with various organic solvents were determined at different temperatures and under ambient pressure. Experimental densities and speed of sound of binary systems of IL with 1-alcohols: 1-heptanol, 1-octanol or 1-nonanol were measured at temperature range from (25 to 35) 0 C. The excess molar volumes ( V E ) and excess isentropic compressibilities ( κ s E ) were derived using the experimental data. The positive to negative V E values were observed for the systems [C 2 mim][MeSO 4 ] with 1-heptanol or 1-octanol whereas the only positive V E values for the 1-nonanol system. Negative κ s E values obtained for the systems [C 2 mim][MeSO 4 ] with 1-heptanol or 1-octanol except higher composition of 1-octanol and positive κ s E values for the 1-nonanol system at all temperatures. A discussion was carried out in terms of interactions and structure factors in these binary mixtures based on results obtained. [ABSTRACT FROM AUTHOR]

The structure and dynamics at the surface of nanoscopic hexadecane droplets immersed in aqueous phase with and without emulsifiers (1-alkanols of varying chain length; pentanol, heptanol, decanol and dodecanol) have been studied using atomistic molecular dynamics simulations. The nature of layering of alcohol molecules on the oil droplet is governed by the hydrophobicity of alkanols. Longer chain alkanols are more likely to penetrate into the oil droplet. The probability of tangential orientation of hexadecane molecules at the interface decreases with decreasing hydrophobic environment around the droplet. The interfacial hexadecane molecules show greater probability to obtain a puckered conformation in binary oil–water system than in ternary oil–water–alkanol systems. Decrease in hydrophobic interaction between hexadecane and water molecules due to the efficient screening of oil surface by longer chain alkanols in ternary oil–water–alkanol systems leads to greater survival probability of water molecules in the oil–water interfacial layer and enhancement in life time of H-bonds formed between alcohol and water molecules. [ABSTRACT FROM AUTHOR]

Measurements on density and viscosity at T = (293.15, 298.15, 303.15, 308.15 313.15, 318.15, 323.15, 328.15, and 333.15) K and the pressure P = 0.1 MPa for binary mixtures of n-dodecane or methylcyclohexane with 1-heptanol or cyclohexylmethanol have been carried out over the whole composition range. Densities were measured with a vibrating-tube densimeter. Viscosities were determined by an automatic microviscometer based on the rolling-ball principle. The excess molar volumes (VmE) and viscosity deviations (Δη) were calculated with experimental data and fitted to the Redlich-Kister equation. The results of these excess or deviation functions are explained by molecular interactions and structural effects. Freezing points were measured with a differential scanning calorimeter. The fundamental data, VmE and Δη can be used to study the nature of mixing behaviors between new hydrocarbon fuels. [ABSTRACT FROM AUTHOR]

BACKGROUND Six corn starch inclusion complexes were synthesized using small nonpolar or weak polar aroma compounds (heptanolide, carvone and menthone) and small polar aroma compounds (linalool, heptanol and menthol). The objectives of this study were to (a) investigate the ability of corn starch to form inclusion complexes with these aroma compounds and (b) characterize the structure of the corn starch inclusion complexes. RESULTS The resulting inclusion ratios were 75.6, 36.9, 43.8, 91.9, 67.2 and 54.7% for heptanolide, carvone, menthone, linalool, heptanol and menthol respectively. The inclusion complexes had laminated structures with a certain amount of holes or blocky constructions. Compared with gelatinized corn starch, the transition temperatures, peak temperatures and enthalpies of the inclusion complexes were significantly different. The major peak of CO at 1771 cm−1 and significant peak shifts revealed the formation of inclusion complexes. X-ray diffractometry ( XRD) analyses revealed that the crystallinity of corn starch-polar aroma compound inclusion complexes increased. Based on cross-polarization magic angle spinning 13C nuclear magnetic resonance ( CP-MAS 13C NMR) results, novel peaks and chemical shifts were attributed to the presence of small aroma compounds, thereby confirming the formation of corn starch inclusion complexes. CONCLUSION Small nonpolar and polar aroma compounds can be complexed to corn starch. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The present study experimentally investigates main combustion, fuel injection, and cycle-by-cycle variations in a CRDI diesel engine fueled with blends of heptanol/iso-propanol/butanol and diesel. Two percentages of diesel and higher alcohol blends, denoted as D85HIB15 (85% diesel, 5% heptanol, 5% iso-propanol, 5% butanol) and D70HIB30 (70% diesel, 10% heptanol, 10% iso-propanol, 10% butanol), were utilized in the engine at different BMEPs (3.4, 5.2, and 6.9 bar). With increasing ratio of the alcohol blends in diesel, it was founded lower CP max, PRR max , and IMEP, prolonged ignition delay, earlier injection timing and combustion center, and also higher injection pressure compared to diesel fuel. Based on the standard deviation and coefficient of variation for 200 consecutive combustion data, diesel-HIB blends showed lower cyclic variations than conventional diesel under all test cases. Notable fluctuations in cycle-by-cycle injection pressure highlighted to cyclic combustion fluctuations. Finally, the relationship between main combustion parameters showed that the highest correlation was around 0.8 between CP max and PRR max for diesel-HIB blends at low load, and for pure diesel and D85HIB15 at medium load, indicating that there was a well linear relationship. • Use of heptanol/iso-propanol/butanol blends in automotive common-rail diesel engine. • Cycle-by-cycle combustion analyses including CPmax, PRRmax, and IMEP. • Reduced cyclic variations in cylinder pressure with the higher alcohol blends. • Reduced cylinder pressure, heat release rate, and pressure rise rate with the higher alcohol blends. • The highest correlation coefficient between peak cylinder pressure and peak pressure rise rate. [ABSTRACT FROM AUTHOR]

This investigation aims to elucidate the roles of lipids on the volatilome evolution of postmortem lamb and its possible modulated mechanism behind. Firstly, the physicochemical properties were evaluated as coordinating role of flavor quality, and results suggested that chilled storage improved tenderness of muscle tissue and induced color variation of lamb. According to multivariate results, the pattern shifts of volatile profile of chilled lamb could be differentiated successfully. Besides, the potential differential aroma-active compounds were identified, including up-regulated heptanol, 1-octen-3-ol, 6-methyl-2-heptanone, 3-heptanone, 2-pentyl furan and octanol in early stage of storage (days 0-3) and down-regulated hexanal, pentanal, hexanol, octanol, 6-methy-2-heptanone, heptanol, 1-octen-3-ol and benzaldehyde in later stage of storage (days 3-7). Then, discriminant analysis recognized the differential lipid species corresponding to different stages of lamb flavor development, involving phospholipids, sphingolipids, glycerolipids and fatty acyls. Herein, the degradation of acyl carnitine and diglyceride may be an important pathway that contributed to volatilome evolution of postmortem lamb in the early stage of storage. These results demonstrated a potential relationship between headspace volatilome and lipidome evolutions, providing a comprehensive understanding for development of lipid-derived volatile compounds of chilled lamb and useful for lamb characteristic flavor quality evaluation and control in future., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

A diepoxide (( E )-1,2-di(7- oxabicyclo [4.1.0]heptan-3-yl)ethane, named DCE), possessing two cyclohexane rings bridged by a double bond was obtained via self-metathesis approach. This unique epoxy structure shows great potential in substantially overcoming the poor performances of plant oil materials in thermal and mechanical aspects. The molecular structure of DCE is more compact and regular than the commercial 3,4-epoxycyclohexylmethyl-3,4- epoxycyclohexanecarboxylate (ECHM) and was evidenced by the small-/wide-angle X-ray scattering. After conetwork was built between epoxidized soybean oil (ESO) and DCE, stiff crosslinks were created through the double bonds of DCE, which restricts the backbone rotation of ESO (P-ESO) networks. DCE-rich domains with dimensions ranging from 0.5 to 2 μm were observed with the increase of DCE, revealed by atomic force microscopy (AFM) phase image and voltage-distance curve. These DCE-rich domains act as micro-scale reinforcements homogenously dispersed in the ESO matrix, effectively sustaining the applied stress and preventing the chain break from high force loading. Compared to P-ESO, the co-polymerized ESO-DCE at 30 wt % DCE loading showed tensile strength of 62 MPa and glass transition temperature of 163 °C that are much higher than 4 MPa and 10 °C for P-ESO, respectively. ECHM also showed significant reinforcement effects on the thermal and mechanical properties of ESO, but DCE's reinforcement effects is doubled compared to ECHM. [ABSTRACT FROM AUTHOR]

In the current study, arrhythmogenic effects of the gap junction inhibitor heptanol (0.05 mM) were examined in Langendorff-perfused mouse hearts. Monophasic action potential recordings were obtained from the left ventricular epicardium during right ventricular pacing. Regular activity was observed both prior and subsequent to application of heptanol in all of the 12 hearts studied during 8 Hz pacing. By contrast, induced ventricular tachycardia (VT) was observed after heptanol treatment in 6/12 hearts using a S1S2 protocol (Fisher's exact test; P<0.05). The arrhythmogenic effects of heptanol were associated with increased activation latencies from 13.2±0.6 to 19.4±1.3 msec (analysis of variance; P<0.001) and reduced conduction velocities (CVs) from 0.23±0.01 to 0.16±0.01 msec (analysis of variance; P<0.001) in an absence of alterations in action potential durations (ADPs) at x=90% (38.0±1.0 vs. 38.3±1.8 msec), 70% (16.8±1.0 vs. 19.5±0.9 msec), 50% (9.2±0.8 vs. 10.1±0.6 msec) or 30% (4.8±0.5 vs. 6.3±0.6 msec) repolarization (APDx) or in effective refractory period (ERPs) (39.6±1.9 vs. 40.6±3.0 msec) (all P>0.05). Consequently, excitation wavelengths (λ; CV x ERP) were reduced from 9.1±0.6 to 6.5±0.6 mm (P<0.01), however critical intervals for re-excitation (APD90 - ERP) were unaltered (-1.1±2.4 vs. -2.3±1.8 msec; P>0.05). Together, these observations demonstrate for the first time, to the best of our knowledge, that inhibition of gap junctions alone using a low heptanol concentration (0.05 mM) was able to reduce CV, which alone was sufficient to permit the induction of VT using premature stimulation by reducing λ, which therefore appears central in the determination of arrhythmic tendency. [ABSTRACT FROM AUTHOR]