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Significant predictors of overall survival in patients with hepatocellular carcinoma after surgical resection
(2018-09-04)
Lin, Chih-Wen
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Chen, Yaw-Sen
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Lin, Chih-Che
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Lee, Po-Huang
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Lo, Gin-Ho
Background The predictive factors of overall survival after hepatectomy for HCC remain controversial and need to be investigated. Methods In total, 535 consecutive HCC patients undergoing resection were included and their clinicopathological data and overall survival were recorded. Both the tumor and adjacent nontumor (ANT) tissues were subjected to immunohistochemistry analysis for the expression of autophagy-related markers. Results Death was observed for 219 patients, and the cumulative overall survival rates at 1, 3, 5 and 7 years were 91.0%, 72.3%, 58.8%, and 27.7%, respectively. In the multivariate analysis, mortality was significantly associated with the following: diminished LC3 expression in both the tumor and ANT tissues, in the HCC tissues alone and in the ANT tissues alone (hazard ratio/95% confidence interval: 6.74/2.052 +/- 22.19, 6.70/1.321 +/- 33.98 and 2.58/1.499 +/- 4.915, respectively); recurrent HCC (5.11/3.136 +/- 8.342); HBV infection (2.75/1.574 +/- 4.784); cirrhosis (1.78/1.059 +/- 2.974); and antiviral therapy (0.42/0.250 +/- 0.697). The 5-year overall survival rates were 70.2%, 57.3%, 49.6% and 10.7% for patients with positive LC3 expression in both tissue types, in the HCC tissues alone, in the ANT tissues alone, and in neither tissue type, respectively. The 5-year overall survival rates were 56.7%, 47.3%, 51.2% and 38.7% for patients with HBV-related HCC, cirrhosis, no antiviral therapy, and recurrent HCC, respectively, and these rates were significantly lower than those in their counterparts. Conclusions Patients with recurrent HCC, HBV-related HCC, cirrhosis, and the absence of antiviral therapy showed significantly lower overall survival rates. Furthermore, LC3 expression in both the tumor and liver microenvironments were significantly predictive of overall survival after resection for HCC.
Discrete element simulation of the dynamic response of a dip slope under shaking table tests
(2018-09-04)
Lin, Cheng-Han
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Li, Hung-Hui
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Weng, Meng-Chia
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土木工程學系
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Department of Civil Engineering
A dip slope contains weak planes in the same dip direction along the slope face. In this study, a discrete element simulation was implemented to investigate the behavior of a dip slope under shaking table tests. The simulated dip slope model was first verified by testing under different horizontal excitations. Then, the influence of the slope angle and dynamic force on the deformation characteristics of the dip slopes was explored. The simulations provide detailed descriptions of the deformation processes and potential sliding mechanisms associated with the dip slopes. The results of this study are summarized as follows: (1) Two types of slope sliding, namely differential and complete, were recognized. The model with a dip angle lower than 20 degrees was more stable, and differential sliding developed gradually during external excitation. In the model with a dip angle higher than 20 degrees, the external excitation easily triggered complete sliding. (2) For threshold slope angles higher than 20 degrees, the behavior of the dip slope model changed from deformation to sliding, and the displacement within the models increased with increasing slope angle. (3) An increase in frequency led to a decrease in the trigger time for slope sliding. In addition, the slope angle was negatively correlated with the triggering time for sliding. (4) The amplification factor of peak ground displacement (PGD) increased as the slope angle increased. The amplification factors corresponding to low excitation frequencies were considerably lower than those for high excitation frequencies. In contrast to the trends for PGD, the amplification factor of peak ground acceleration (PGA) decreased as the slope angle increased.
交大e-News第262期-TAICHI 2018跨域合作激盪人機互動新方向
(2018-09-05)
國立交通大學秘書室
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Secretariat
Activation Energy Distribution of Dynamical Structural Defects in RuO2 Films
(2018-09-05)
Yeh, Sheng-Shiuan
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Gao, Kuang Hong
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Wu, Tsung-Lin
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Su, Ta-Kang
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Lin, Juhn-Jong
Ruthenium dioxide (RuO2) is an important metal widely used in nanoelectronic devices. It plays indispensable roles in applications such as catalysts and supercapacitors. A good understanding of the origin of the flicker or 1/f noise in RuO2 will advance the design and efficiency of these applications. We demonstrate in a series of sputtered RuO2 polycrystalline films that the 1/f noise originates from fluctuating oxygen vacancies which act as dynamical structural defects, i.e., moving scattering centers. Reducing the number of oxygen vacancies by adjusting thermal annealing conditions significantly reduces the noise magnitude gamma, the Hooge parameter. We quantify the activation energy distribution function, g(E), and calculate the oxygen vacancy density, n(TLS), from the measured gamma value. We show that g(E) can be explicitly expressed in terms of gamma(T) and the electronic parameters of the metal, where T denotes temperature. The inferred n(TLS) value is in line with the oxygen content determined from the x-ray photoelectron spectroscopy studies.
Development of extremely stable dual functionalized gold nanoparticles for effective colorimetric detection of clenbuterol and ractopamine in human urine samples
(2018-09-06)
Simon, Turibius
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Shellaiah, Muthaiah
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Steffi, Perpectual
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Sun, Kien Wen
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Ko, Fu-Hsiang
New glutamic acid (Glu) and polyethylenimine (PE) functionalized ultra-stable gold nanoparticles (PE-Glu-AuNPs) were developed via a simple NaBH4 reduction method. The low toxicity and biocompatibility of PE-Glu-AuNPs were confirmed via an MTT assay in Raw 264.7 cells. Excitingly, PE-Glu-AuNPs were found to be extremely stable at room temperature up to six months and were utilized in an effective colorimetric naked eye assay of clenbuterol (CLB) and ractopamine (RCT) at pH 5. It was found that the selective assay of CLB and RCT is not affected by any other interferences (such as alanine, phenylalanine, NaCl, CaCl2, threonine, cysteine, glycine, glucose, urea and salbutamol). Furthermore, the detection of these beta-agonists can be visually accomplished through change color from wine red to purple blue. Notably, the aggregation induced detection of CLB and RCT was well confirmed through transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies. DLS investigations, clearly showed, that in the presence of CLB and RCT, the initial size of PE-Glu-AuNPs (12.8 +/- 8.6 nm) was changed to 84.8 +/- 52.3 and 79.5 +/- 47.8 nm, respectively, via aggregation. Furthermore, the colorimetric assays of CLB and RCT with PE-Glu-AuNPs were effective starting from CLB and RCT concentrations of 200 nM and 400 nM, respectively, and could be visualized using the naked eyes. Remarkably, UV-vis titrations of PE-Glu-AuNPs with CLB and RCT could be used to well estimate their sub nanomolar detection limits (LODs) via standard deviation and linear fittings. The contribution of surface functional groups that support the analyte recognition was confirmed by fourier-transform infrared spectroscopy (FTIR) analysis. Moreover, the CLB and RCT assays with PE-Glu-AuNPs were supported by examination of human urine samples. (C) 2018 Elsevier B.V. All rights reserved.
Atomic layer oxidation on graphene sheets for tuning their oxidation levels, electrical conductivities, and band gaps
(2018-09-07)
Gu, Siyong
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Hsieh, Chien-Te
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Lin, Tzu-Wei
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Yuan, Chun-Yao
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Gandomi, Yasser Ashraf
Graphene sheets that can exhibit electrical conducting and semiconducting properties are highly desirable and have potential applications in fiber communications, photodetectors, solar cells, semiconductors, and broadband modulators. However, there is currently no efficient method that is able to tune the band gap of graphene sheets. This work adopts an efficient atomic layer oxidation (ALO) technique to cyclically increase the oxidation level of graphene sheets, thus, tuning their electrical conductance, band-gap structure, and photoluminescence (PL) response. The O/C atomic ratio as an increasing function of the ALO cycle number reflects two linear regions: 0.23% per cm(2) per cycle (0-15 cycles) and 0.054% per cm(2) per cycle (15-100 cycles). The excellent correlation coefficients reveal that the ALO process follows a self-limiting route to step-by-step oxidize graphene layers. The interlayer distance of ALO-graphene sheets shows an obvious increase after the ALO treatment, proved by X-ray diffraction. As analyzed by X-ray photon spectroscopy, the hydroxyl or epoxy group acts as a major contributor to the interlayer spacing distance and oxidation extent in the initial ALO stage, as compared to carbonyl and carboxyl groups. The ALO mechanism, based on Langmuir-Hinshelwood and Eley-Rideal models, is proposed to clarify the formation of oxygen functionalities and structural transformation from pristine graphene sheets to oxidized ones during the ALO cycle. With a tunable oxidation level, the electrical resistivity, semiconductor character, and PL response of ALO-graphene samples can be systematically controlled for desired applications. The ALO approach is capable of offering a straightforward route to tune the oxidation level of graphene sheets or other carbons.
Fibroblast-seeded collagen gels in response to dynamic equibiaxial mechanical stimuli: A biomechanical study
(2018-09-10)
Lee, Pei-Yuan
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Liu, Yen-Ching
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Wang, Mei-Xuan
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Hu, Jin-Jia
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機械工程學系
The remodeling of fibroblast-seeded collagen gels in response to dynamic mechanical stimuli was investigated by using a newly developed biaxial culture system capable of cyclically stretching planar soft tissues. Fibroblast-seeded collagen gels were subjected to three distinct dynamic mechanical conditions for six days: Cyclic Equibiaxial Stretching at two constant strain magnitudes (CES-7% and CES-20%), and Cyclic Equibiaxial Stretching with incrementally Increasing stain magnitude (ICES, 7% 15% 20% each for two days). The frequency of cyclic stretching was set at 1 Hz. At the end of culture, mechanical properties of the gels were examined by biaxial mechanical testing and checked again upon the removal of seeded cells. Collagen microstructure within the gels was illustrated by multiphoton microscopy. The mRNA levels of collagen type I and type III and fibronectin in the cells were examined by reverse transcription PCR. The protein expression of alpha-smooth muscle actin was detected by immunohistochemistry. We found that the gels cultured under cyclic stretching were stiffer than those cultured under static stretching. Particularly, the stiffness appeared to be significantly enhanced when the ICES was employed. The enhancement of mechanical properties by cyclic stretching appeared to persist upon cell removal, suggesting an irreversible remodeling of extracellular matrix. Second harmonic generation images showed that collagen fibers became thicker and more compact in the gels cultured under cyclic stretching, which may explain the mechanical findings. The mRNA expression of collagen type I in the cells of the ICES was significantly greater than that of the other groups except for the CES-20%. This study suggests that when cyclic stretching is to be used in engineering soft tissues, incrementally increasing strain magnitude may prove useful in the development of the tissue. (C) 2018 Elsevier Ltd. All rights reserved.
Efficient modulation of subwavelength focusing via meta-aperture-based plasmonic lens for multifunction applications
(2018-09-11)
Chang, Kai-Hao
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Chen, Yen-Chun
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Chang, Wen-Hao
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Lee, Po-Tsung
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電子物理學系
Subwavelength focusing is crucial for many applications in photonics including super-resolution micro/nanoscopy, nanolithography, and optical trapping. However, most nanostructures exhibit poor ability to modulate focusing spot, which makes them hard to achieve ultra-small resolution. Here, we propose three kinds of plasmonic lens (PL) by utilizing different meta-aperture designs for efficient subwavelength focusing modulation. The shape of nanoaperture strongly influences the diffraction properties. Spatial modulation of focusing spot by employing a circular array of proposed nanoapertures is explored. The best focusing performance among these PLs is the design of T-shape nanoaperture, which has great resolution achieving ultra-small focusing spot of 0.14.2 and 0.20.2 (lambda = 633 nm) for simulation and experiment respectively, better than lots of focusing devices especially by using linear polarization. Multiple-object trapping can be realized by using T-shape nanoaperture-based PL. Our designed PLs with different nanoapertures demonstrate the capability to broaden and integrate different functionalities for on-chip nanotechnologies development.
Using Magnetic Ions to Probe and Induce Magnetism of Pyrophosphates, Bacteria, and Mammalian Cells
(2018-09-12)
Wei, Jia-Lin
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Chen, Yu-Chie
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應用化學系
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Department of Applied Chemistry
Magnetic isolation using magnetic nanoparticles (MNPs) as trapping probes have been widely used in sample pretreatment to shorten analysis time. Nevertheless, to generate MNPs is time-consuming. Furthermore, the generated MNPs have to be further functionalized to gain the capability of recognizing their target species. Thus, an alternative approach that can impose magnetism to nonmagnetic species by simply using magnetic ions as the probes is developed in this study. That is, we employ magnetic ions (Fe3+, Co2+, and Ni2+) that can interact with nonmagnetic species containing oxygen-containing functional groups as the probes. Pyrophosphate (PPi), bacteria, and mammalian cells were selected as the model samples. Our results show that the as-prepared magnetic ion PPi conjugates gain sufficient magnetism and can be readily aggregated by applying an external magnetic field. Moreover, the magnetic trapping is reversible. The PPi-containing conjugates can lose their magnetic property simply using ethylenediaminetetraacetic acid or aluminum ions as competing agents to remove or to replace, respectively, the conjugated magnetic ions. In addition, bacteria and mammalian cells that possess abundant oxygen-containing functional groups on their cell surfaces can be selectively probed by magnetic ions and gain sufficient magnetism for magnetic isolation from complex serum samples.
Functionalization of Graphene Oxide Films with Au and MoOx Nanoparticles as Efficient p-Contact Electrodes for Inverted Planar Perovskite Solar Cells
(2018-09-12)
Bhosale, Sumit S.
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Jokar, Efat
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Fathi, Amir
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Tsai, Cheng-Min
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Wang, Chi-Yung
A graphene oxide (GO) film is functionalized with metal (Au) and metal-oxide (MoOx) nanoparticles (NPs) as a hole-extraction layer for high-performance inverted planar-heterojunction perovskite solar cells (PSCs). These NPs can increase the work function of GO, which is confirmed with X-ray photoelectron spectra, Kelvin probe force microscopy, and ultraviolet photoelectron spectra measurements. The down-shifts of work functions lead to a decreased level of potential energy and hence increased V-oc of the PSC devices. Although the GO-AuNP film shows rapid hole extraction and increased V-oc, a J(sc) improvement is not observed because of localization of the extracted holes inside the AuNP that leads to rapid charge recombination, which is confirmed with transient photoelectric measurements. The power conversion efficiency (PCE) of the GO-AuNP device attains 14.6%, which is comparable with that of the GO-based device (14.4%). In contrast, the rapid hole extraction from perovskite to the GO-MoOx layer does not cause trapping of holes and delocalization of holes in the GO film accelerates rapid charge transfer to the indium tin oxide substrate; charge recombination in the perovskite/GO-MoOx interface is hence significantly retarded. The GO-MoOx device consequently shows significantly enhanced V-oc and J(sc), for which its device performance attains PCE of 16.7% with great reproducibility and enduring stability.
Long-reach 60-GHz MMWoF link with free-running laser diodes beating
(2018-09-12)
Tsai, Cheng-Ting
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Li, Chien-Cheng
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Lin, Chi-Hsiang
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Lin, Chun-Ting
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Chi, Sien
With the remote beating of two mutually incoherent laser carriers, the local-oscillator-free long-reach millimeter-wave over fiber (MMWoF) link at 60-GHz band is demonstrated. The unique schemes of the proposed MMWoF are the wavelength-locked colorless laser diode (CLD) modulator, the mutually incoherent optical carrier for heterodyne MMW generation, and the square-law power envelope detection at receiving end. By directly encoding the single-mode with the CLD modulator, the singlecarrier modulated QAM-OFDM data is achieved to release the RF power fading after fiber transmission. The mutually incoherent laser beating enables the optical heterodyne MMW generation with two independent optical carriers, which provides the advantages of local-oscillator-free operation and rules out the requirement of dual-mode optical carrier delivery from central office. At the wireless receiving end, the received QAM-OFDM data is self-down-converted to the baseband by employing the square-law power envelope detection. This eliminates the requirement of local oscillator and rules out the influence of the MMW carrier frequency fluctuation between two mutually incoherent lasers (used at central office and remote node), which effectively provides the MMW carrier immunity against the down-conversion instability caused by clock jitter or carrier incoherence. This architecture ensures the transmission of 16.5-Gbit/s 32-QAM OFDM data over 50 km in SMF and 3 m in free-space with the FEC certificated error vector magnitude of 12%, signal-to-noise ratio (SNR) of 18.4 dB, and bit error rate of 3.8 x 10(-3). For multi-channel DWDM-PON applications, the proposed local-oscillator-free MMWoF link can successfully perform 11 DWDM channels of 32-QAM OFDM data access at 16.5 Gbit/s per channel via the wavelength controlling of the CLD modulation stage and the detuning of the beating carrier at remote node.
Transparent Antiradiative Ferroelectric Heterostructure Based on Flexible Oxide Heteroepitaxy
(2018-09-12)
Ma, Chun-Hao
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Jiang, Jie
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Shao, Pao-Wen
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Peng, Qiang-Xiang
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Huang, Chun-Wei
In the era of Internet of Things, the demand for flexible and transparent electronic devices has shifted to the forefront of materials science research. However, the radiation damage to key performance of transparent devices under radiative environment remains as a critical issue. Here, we present a promising technology for nonvolatile transparent electronic devices based on flexible oxide heteroepitaxy. A direct fabrication of epitaxial lead lanthanum zirconate titanate on transparent flexible mica substrate with indium tin oxide electrodes is presented. The transparent flexible ferroelectric heterostructures not only retain their superior performance, thermal stability, reliability, and mechanical durability, but also exhibit remarkably robust properties against to a strong radiation exposure. Our study demonstrates an extraordinary concept to realize transparent flexible nonvolatile electronic devices for the design and development of next-generation smart devices with potential application in electronics, automotive, aerospace, and nuclear systems.
METHOD AND SYSTEM FOR DETERMINING DATA ASSOCIATED WITH LOWER LIMB ACTIVITY
(2018-09-13)
Bing-Shiang YANG
;
Yu-Tang WEN
A method includes steps of: measuring a variation in joint angle of a knee of a cyclist to obtain joint angle data; sensing a torque applied on a crank of a cycle or pedaling force applied to a pedal of the cycle to obtain force data; measuring an angular position of the crank to obtain crank angle data; measuring an electrical potential variation of a measured muscle of the cyclist to generate a measured EMG signal; estimating activation data and joint moment data based on aforementioned data and characteristics data; converting the activation data into estimated EMG signals based on the measured EMG signal and the activation data; and computing a coactivation parameter based on the aforementioned EMG signals.
DISPLAY SYSTEM
(2018-09-13)
Hung-Shan CHEN
;
Yi-Hsin LIN
An optical system for aberration compensation comprising an optical module and an asymmetric refractive index distribution film is disclosed. The asymmetric refractive index distribution film comprises a liquid crystal and a liquid crystalline polymer, wherein the asymmetric refractive index distribution film set on an out-light surface or an in-light surface of the optical module. A display system comprising the above-mentioned optical system and an image panel are also disclosed herein. The asymmetric refractive index distribution film of the present invention has non-uniform refractive index distribution so as to effectively compensate the aberration formed by the optical module.
Impact of intrinsic amorphous silicon bilayers in silicon heterojunction solar cells
(2018-09-14)
Sai, Hitoshi
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Chen, Po-Wei
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Hsu, Hung-Jung
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Matsui, Takuya
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Nunomura, Shota
The impact of intrinsic amorphous silicon bilayers in amorphous silicon/crystalline silicon (a-Si:H/ c-Si) heterojunction solar cells is investigated. The microstructure factor R* of the interfacial a-Si: H layer, which is related to the Si-H bond microstructure and determined by infrared absorption spectroscopy, is controlled in a wide range by varying the growth pressure and the power density in plasma-enhanced chemical vapor deposition process. Surface passivation at the a-Si:H/c-Si interface is significantly improved by using an intrinsic a-Si:H bilayer, i.e., a stack of an interfacial layer with a large R* and an additional dense layer, particularly after the deposition of an overlying p-type a-Si:H layer. Consequently, the conversion efficiency of a-Si:H/c-Si heterojunction solar cells is markedly increased. However, it is also revealed that such an interfacial layer causes some negative effects including the increase in the series resistance and the current loss at the front side, depending on the growth condition. This result indicates that the interfacial layer has a significant impact on both the majority and the minority carrier transport. Thus, R* of the interfacial layer is an important parameter for obtaining good surface passivation at the a-Si/c-Si interface, but not the sole parameter determining the conversion efficiency of a-Si:H/c-Si heterojunction solar cells. Published by AIP Publishing.
Two-dimensional pulse dynamics and the formation of bound states on electrified falling films
(2018-09-14)
Blyth, M. G.
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Tseluiko, D.
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Lin, T-S
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Kalliadasis, S.
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應用數學系
The flow of an electrified liquid film down an inclined plane wall is investigated with the focus on coherent structures in the form of travelling waves on the film surface, in particular, single-hump solitary pulses and their interactions. The flow structures are analysed first using a long-wave model, which is valid in the presence of weak inertia, and second using the Stokes equations. For obtuse angles, gravity is destabilising and solitary pulses exist even in the absence of an electric field. For acute angles, spatially non-uniform solutions exist only beyond a critical value of the electric field strength; moreover, solitary-pulse solutions are present only at sufficiently high supercritical electric-field strengths. The electric field increases the amplitude of the pulses, can generate recirculation zones in the humps and alters the far-field decay of the pulse tails from exponential to algebraic with a significant impact on pulse interactions. A weak-interaction theory predicts an infinite sequence of bound-state solutions for non-electrified flow, and a finite set for electrified flow. The existence of single-hump pulse solutions and two-pulse bound states is confirmed for the Stokes equations via boundary-element computations. In addition, the electric field is shown to trigger a switch from absolute to convective instability, thereby regularising the dynamics, and this is confirmed by time-dependent simulations of the long-wave model.
Observing phase transformation in CVD-grown MoS2 via atomic resolution TEM
(2018-09-14)
Tai, Kuo-Lun
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Huang, Guan-Min
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Huang, Chun-Wei
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Tsai, Tsung-Chun
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Lee, Shih-Kuang
We utilized in situ transmission electron microscopy to observe phase transformation in CVD-grown MoS2. Significantly, the reaction was performed under electron irradiation through appropriate control of the electron dose and exposure time. Moreover, we proposed a new route between the 2H and 1T phases that involved the higher energy states TS1/TS2.
The study of pixelated sampling and its influences on the 2nd-order spatial coherence measurement
(2018-09-15)
Li, Jie-En
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Tien, Chung-Hao
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光電工程學系
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Department of Photonics
Since the measurement of spatial coherence requires multiple sampling to acquire the complex coherence factor of a wavefield, it is convenient to accomplish such dynamic work by a non-redundant multi-slit through a programmable device such as spatial light modulator (SLM). In this study, we examined the influence of SLM-like pixelated structure, parameterized by whose fill factor, on both intensity distribution (first-order statistics) and complex coherence factor (second-order statistics). Based on the generalized Van Cittert-Zernike theorem that as the source satisfied the quasi-homogeneous condition, the coherence factor of the wavefield was irrelevant to the pixelated sampling structure. The inference was validated by a SLM-based experiment from a pseudothermal light source. We expected this work to be useful for future dynamic coherence measurement.
Formation of gradient Ga distribution in Cu(In,Ga)Se-2 thin-film solar cells prepared by (InGa)(2)Se-3/CuInGaSe2 stacking structure followed by Se-Vapor selenization
(2018-09-15)
Lin, Yu-Pin
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Hsieh, Tsung-Eong
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Chen, Yen-Chih
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Huang, Kun-Ping
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材料科學與工程學系
Cu(In,Ga)Se-2 (CIGS) light absorption layers with gradient Ga distribution were prepared by utilizing the sequential deposition of (InGa)(2)Se-3 (IGS) and CIGS layers. The IGS buffer layers were deposited on Mo/soda lime glass substrate at various working pressures (WP = 1, 10 and 30 mtorr) followed by the deposition of CIGS layers. Afterward, the microstructures and compositions of CIGS layers formed by the selenization of CIGS/IGS stacking layers in Se vapor ambient at 560 degrees C for 1 h were investigated. The CIGS layer with the optimized microstructure and transport properties was then implanted in the thin-film solar cells and the device with the best conversion efficiency of 8.22 +/- 0.0754% was achieved. The satisfactory solar cell performance was ascribed to the insertion of IGS layer which remedies the deficiency of In, Ga and Se elements and forms the gradient Ga distribution in CIGS layer as revealed by the secondary ion mass spectroscopy.
Sex-specific activation of SK current by isoproterenol facilitates action potential triangulation and arrhythmogenesis in rabbit ventricles
(2018-09-15)
Chen, Mu
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Yin, Dechun
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Guo, Shuai
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Xu, Dong-Zhu
;
Wang, Zhuo
Sex has a large influence on cardiac electrophysiological properties. Whether sex differences exist in apamin-sensitive small conductance Ca2+-activated K+ (SK) current (I-KAS) remains unknown. We performed optical mapping, transmembrane potential, patch clamp, western blot and immunostaining in 62 normal rabbit ventricles, including 32 females and 30 males. I-KAS blockade by apamin only minimally prolonged action potential (AP) duration (APD) in the basal condition for both sexes, but significantly prolonged APD in the presence of isoproterenol in females. Apamin prolonged APD at the level of 25% repolarization (APD(25)) more prominently than APD at the level of 80% repolarization (APD(80)), consequently reversing isoproterenol-induced AP triangulation in females. In comparison, apamin prolonged APD to a significantly lesser extent in males and failed to restore the AP plateau during isoproterenol infusion. I-KAS in males did not respond to the L-type calcium current agonist BayK8644, but was amplified by the casein kinase 2 (CK2) inhibitor 4,5,6,7-tetrabromobenzotriazole. In addition, whole-cell outward I-KAS densities in ventricular cardiomyocytes were significantly larger in females than in males. SK channel subtype 2 (SK2) protein expression was higher and the CK2/SK2 ratio was lower in females than in males. I-KAS activation in females induced negative intracellular Ca2+-voltage coupling, promoted electromechanically discordant phase 2 repolarization alternans and facilitated ventricular fibrillation (VF). Apamin eliminated the negative Ca2+-voltage coupling, attenuated alternans and reduced VF inducibility, phase singularities and dominant frequencies in females, but not in males. We conclude that beta-adrenergic stimulation activates ventricular I-KAS in females to a much greater extent than in males. I-KAS activation plays an important role in ventricular arrhythmogenesis in females during sympathetic stimulation.