205 research outputs found
Endothelin-Induced Sarcoplasmic Reticulum Calcium Depletion Waves in Vascular Smooth Muscle Cells
Agonist-stimulated waves of elevated cytoplasmic Ca2+ concentration ([Ca2+]i ) regulate blood vessel tone and vasomotion in vascular smooth muscle. Previous studies employing cytoplasmic Ca2+ indicators revealed that these Ca2+ waves were generated by a combination of inositol 1,4,5-trisphosphate (IP3) and Ca2+ induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR); although, some of the mechanistic details remain uncertain. However, these findings were derived indirectly from observing agonist-induced [Ca2+]i fluctuations in the cytoplasm.
Here, for the first time, we have recorded Endothelin-1 (ET-1) induced waves of Ca2+ depletion from the SR lumen in vascular smooth muscle cells (VSMCs) using a calsequestrin-targeted Ca2+ indicator. Our findings show that these waves: (1) are due to regenerative CICR by the receptors for IP3 (IP3R), (2) have a marked latency period, (3) are characterized by a transient increase in SR Ca2+ ([Ca2+]SR ) both at the point of origin and at the wave front, (4) proceed with diminishing velocity, and (5) are arrested by the nuclear envelope. Our quantitative model indicates that the gradual decrease in the velocity of the SR depletion wave, in the absence of external Ca2+, results from continuity of the SR luminal network
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Knowledge Appropriation and Inventive Productivity
Innovation is critical for firm growth and survival. Thus, how much value firms create and capture from their innovative activities has been an interest of scholars. This dissertation explores three important questions on this topic to which extant literature has paid little attention. First, I examine how the external threat caused by a bankruptcy event in an industry affect industry firms’ innovative activities. Although extant research has examined how firm-specific threats (e.g., firm’s own bankruptcy risk and operating performance) affect firm innovative activities, little is known about how the common threat in an industry affects firm innovative activities. Drawing on threat-rigidity theory, I propose that the threat caused by bankruptcy leads firms to reduce innovative activities and that this effect may depend on the firm’s own situation – firm’s own bankruptcy risk. Second, I examine how trade secrecy helps firms capture value from innovative activities. Despite trade secrecy’s importance and calls to examine factors that moderate the effectiveness of trade secrecy, there have been few empirical studies of when trade secrecy is most effective. I propose that trade secrecy may have a positive effect on firm financial returns to R&D activities and that this effect is contingent upon concurrent use of other appropriation mechanisms and industrial conditions. Third, I examine how firms can capture more value from innovative activities by building on its own inventions – generative appropriation. I propose that technological knowledge dispersion has a negative effect on generative appropriation while geographic knowledge dispersion has a curvilinear effect; I also propose that these effects are stronger when environmental technology opportunities are smaller. Overall, the findings of this study supported my hypotheses
Invisible Computing
The computer is no longer a tool solely used for enhancing the productivity of organizational tasks. Rather, computing capability now is embedded into our everyday artifacts, enabling our daily activities to become smarter and easier. As a result, the way we interact with computers has radically changed in the past few years: computing is now being designed for activity-oriented users. Thus, as IS and HCI scholars have discussed, computing should be designed to be invisible. By invisible we mean the phenomenon that users are not conscious of the computing that they are using. The degree of invisibility largely depends on user interfaces of computing. The concept of invisibility has been used among IS and HCI scholars. However, detailed analysis on invisibility as a construct has not been conducted. Therefore, in this paper, we will investigate 1) where and how the concept of invisibility has been used in the literature, 2) a new theoretical framework for the concept of invisibility in computing, and 3) how this concept can provide practical implications by applying it to a related case. In this paper, we focus on the relation between computing devices and users at the individual level with respect to degrees of invisibility
Comparison of genetic variations between high- and low-risk Listeria monocytogenes isolates using whole-genome de novo sequencing
In this study, genetic variations and characteristics of Listeria monocytogenes isolates from enoki mushrooms (23), smoked ducks (7), and processed ground meat products (30) were examined with respect to hemolysis, virulence genes, growth patterns, and heat resistance. The isolates that showed the highest pathogenicity and the lowest pathogenicity were analyzed to obtain the whole-genome sequence, and the sequences were further analyzed to identify genetic variations in virulence, low-temperature growth-related, and heat resistance-related factors. All isolates had β-hemolysis and virulence genes (actA, hlyA, inlA, inlB, and plcB). At low temperatures, isolates with high growth (L. monocytogenes strains SMFM 201803 SD 1-1, SMFM 201803 SD 4-2, and SMFM 201804 SD 5-3) and low growth (L. monocytogenes strains SMFM 2019-FV43, SMFM 2019-FV42, and SMFM 2020-BT30) were selected. Among them, L. monocytogenes SMFM 201804 SD 5-3 showed the highest resistance at 60°C and 70°C. The strains SMFM 201804 SD 5-3 (high-risk) and SMFM 2019-FV43 (low-risk) harbored 45 virulence genes; 41 single nucleotide variants (SNVs) were identified between these two isolates. A comparison of 26 genes related to low-temperature growth revealed 18 SNVs between these two isolates; a comparison of the 21 genes related to heat resistance revealed 16 SNVs. These results indicate that the differences in the pathogenicity of L. monocytogenes SMFM 201804 SD 5-3 and L. monocytogenes SMFM 2019-FV43 are associated with the SNVs identified in virulence genes, low-temperature growth-related genes, and heat resistance-related genes
Endometrial Response to Conceptus-Derived Estrogen and Interleukin-1β at the Time of Implantation in Pigs
The establishment of pregnancy is a complex process that requires a well-coordinated interaction between the implanting conceptus and the maternal uterus. In pigs, the conceptus undergoes dramatic morphological and functional changes at the time of implantation and introduces various factors, including estrogens and cytokines, interleukin-1β2 (IL1B2), interferon-γ (IFNG), and IFN-δ (IFND), into the uterine lumen. In response to ovarian steroid hormones and conceptus-derived factors, the uterine endometrium becomes receptive to the implanting conceptus by changing its expression of cell adhesion molecules, secretory activity, and immune response. Conceptus-derived estrogens act as a signal for maternal recognition of pregnancy by changing the direction of prostaglandin (PG) F2α from the uterine vasculature to the uterine lumen. Estrogens also induce the expression of many endometrial genes, including genes related to growth factors, the synthesis and transport of PGs, and immunity. IL1B2, a pro-inflammatory cytokine, is produced by the elongating conceptus. The direct effect of IL1B2 on endometrial function is not fully understood. IL1B activates the expression of endometrial genes, including the genes involved in IL1B signaling and PG synthesis and transport. In addition, estrogen or IL1B stimulates endometrial expression of IFN signaling molecules, suggesting that estrogen and IL1B act cooperatively in priming the endometrial function of conceptus-produced IFNG and IFND that, in turn, modulate endometrial immune response during early pregnancy. This review addresses information about maternal-conceptus interactions with respect to endometrial gene expression in response to conceptus-derived factors, focusing on the roles of estrogen and IL1B during early pregnancy in pigs
Synthesis and Applications of Dicationic Iodide Materials for Dye-Sensitized Solar Cells
Dye-sensitized solar cells (DSSCs) have been receiving growing attentions as a potential alternative to order photovoltaic devices due to their high efficiency and low manufacturing cost. DSSCs are composed of a photosensitizing dye adsorbed on a mesoporous film of nanocrystalline TiO2 as a photoelectrode, an electrolyte containing triiodide/iodide redox couple, and a platinized counter electrode. To improve photovoltaic properties of DSSCs, new dicationic salts based on ionic liquids were synthesized. Quite comparable efficiencies were obtained from electrolytes with new dicationic iodide salts. The best cell performance of 7.96% was obtained with dicationic salt of PBDMIDI
Blue cadmium-free and air-fabricated quantum dot light-emitting diodes
The article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Quantum dot (QD) materials have found increasing use in display applications because of their high color purity and fluorescence quantum yield, enabling devices with higher brightness and efficiency. However, to access large-area printing and coating methods that are carried out in ambient conditions, it is necessary to, first, move away from toxic cadmium, and second, to target materials that can be air-processed. Herein, we synthesize zinc selenide-based blue QD material and air-fabricate light-emitting diodes (LEDs) and single-carrier devices. The encapsulated devices were also measured under ambient conditions. Multi-shell-structured ZnSeTe/ZnSe/ZnS (core/shell/shell) QDs show pure deep blue/purple fluorescence emission with a high photoluminescence quantum yield of 78%. The blue QD-LED devices are fabricated in a conventional structure with bottom light emission with two electron transport materials (ZnO and ZnMgO). The QD-LED devices with ZnO electron transport layer show a maximum luminance of ∼6200 cd m−2 at 9 V with a turn-on voltage of 3.5 V and current efficacy of 0.38 cd A−1, while with ZnMgO electron transport layer, the devices show a maximum luminance of 3000 cd m−2 at 7 V with a turn-on voltage of 3 V and current efficacy of 0.6 cd A−1. Electron-only and hole-only devices were fabricated to show and confirm the underlying charge transport mechanisms. To our knowledge, these results show for the first-time air-fabricated ZnSe-based QD-LEDs, paving the way for scaling up display applications and moving toward high-performance printed electronics.Peer Reviewe
Effects of Ecklonia cava as fucoidan-rich algae on growth performance, nutrient digestibility, intestinal morphology and caecal microflora in weanling pigs
Objective: In the present study, role of increasing levels of Ecklonia cava (seaweed) supple mentation in diets was investigated on growth performance, coefficient of total tract apparent digestibility (CTTAD) of nutrients, serum immunoglobulins, cecal microflora and intestinal morphology of weanling pigs. Methods: A total of 200 weaned pigs (Landrace×Yorkshire×Duroc; initial body weight 7.08±0.15 kg) were randomly allotted to 4 treatments on the basis of body weight. There were 5 replicate pens in each treatment including 10 pigs of each. Treatments were divided by dietary Ecklonia cava supplementation levels (0%, 0.05%, 0.1%, or 0.15%) in growing finishing diets. There were 2 diet formulation phases throughout the experiment. The pigs were offered the diets ad libitum for the entire period of experiment in meal form. Results: The pigs fed with increasing dietary concentrations of Ecklonia cava had linear increase (p<0.05) in the overall average daily gain, however, there were no significant differences in gain to feed ratio, CTTAD of dry matter and crude protein at both phase I and phase II. Digestibility of gross energy was linearly improved (p<0.05) in phase II. At day 28, pigs fed Ecklonia cava had greater (linear, p<0.05) Lactobacillus spp., fewer Escherichia coli (E. coli) spp. (linear, p<0.05) and a tendency to have fewer cecal Clostridium spp. (p = 0.077). The total anaerobic bacteria were not affected with supplementation of Ecklonia cava in diets. Polynomial contrasts analysis revealed that villus height of the ileum exhibited a linear increase (p<0.05) in response with the increase in the level of dietary Ecklonia cava. However, villus height of duodenum and jejunum, crypt depth, villus height to crypt depth ratio of different segments of the intestine were not affected. Conclusion: The results suggest that Ecklonia cava had beneficial effects on the growth performance, cecal microflora, and intestinal morphology of weanling pigs
Star-gas misalignment in galaxies: I. The properties of galaxies from the Horizon-AGN simulation and comparisons to SAMI
Recent integral field spectroscopy observations have found that about 11% of
galaxies show star-gas misalignment. The misalignment possibly results from
external effects such as gas accretion, interaction with other objects, and
other environmental effects, hence providing clues to these effects. We explore
the properties of misaligned galaxies using Horizon-AGN, a large-volume
cosmological simulation, and compare the result with the result of the
Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy Survey.
Horizon-AGN can match the overall misalignment fraction and reproduces the
distribution of misalignment angles found by observations surprisingly closely.
The misalignment fraction is found to be highly correlated with galaxy
morphology both in observations and in the simulation: early-type galaxies are
substantially more frequently misaligned than late-type galaxies. The gas
fraction is another important factor associated with misalignment in the sense
that misalignment increases with decreasing gas fraction. However, there is a
significant discrepancy between the SAMI and Horizon-AGN data in the
misalignment fraction for the galaxies in dense (cluster) environments. We
discuss possible origins of misalignment and disagreement.Comment: 23 pages with 15 figures. Accepted for publication in Ap
Star-Gas Misalignment in Galaxies. I. The Properties of Galaxies from the Horizon-AGN Simulation and Comparisons to SAMI
Recent integral field spectroscopy observations have found that about 11% of galaxies show star-gas misalignment. The misalignment possibly results from external effects such as gas accretion, interaction with other objects, and other environmental effects, hence providing clues to these effects. We explore the properties of misaligned galaxies using Horizon-AGN, a large-volume cosmological simulation, and compare the results with those of the Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy Survey. Horizon-AGN can match the overall misalignment fraction and reproduces the distribution of misalignment angles found by observations surprisingly closely. The misalignment fraction is found to be highly correlated with galaxy morphology both in observations and in the simulation: early-type galaxies are substantially more frequently misaligned than late-type galaxies. The gas fraction is another important factor associated with misalignment in the sense that misalignment increases with decreasing gas fraction. However, there is a significant discrepancy between the SAMI and Horizon-AGN data in the misalignment fraction for the galaxies in dense (cluster) environments. We discuss possible origins of misalignment and disagreement.S.K.Y.
acted as the corresponding author and acknowledges support
from the Korean National Research Foundation (NRF2017R1A2A05001116). D.J.K. acknowledges support from
Yonsei University through Yonsei Honors Scholarship. J.J.B.
acknowledges support from an Australian Research Council
Future Fellowship (FT180100231). J.B.H. is supported by an
ARC Laureate Fellowship that funds Jesse van de Sande
and an ARC Federation Fellowship that funded the SAMI
prototype. M.S.O. acknowledges funding support from the
Australian Research Council through a Future Fellowship
(FT140100255). J.v.d.S. is funded under Bland-Hawthorn’s
ARC Laureate Fellowship (FL140100278). Parts of this
research were conducted by the Australian Research Council
Centre of Excellence for All Sky Astrophysics in 3 Dimensions
(ASTRO 3D), through project No. CE170100013. This work
relied on the HPC resources of the Horizon Cluster hosted by
Institut d’Astrophysique de Paris. We warmly thank S.
Rouberol for running the cluster on which the simulation was
post-processed. This work is partially supported by the Spin(e)
grant ANR-13-BS05-0005 of the French Agence Nationale de
la Recherche. The SAMI Galaxy Survey is based on
observations made at the Anglo-Australian Telescope. The
Sydney-AAO Multi-object Integral field spectrograph (SAMI)
was developed jointly by the University of Sydney and the
Australian Astronomical Observatory. The SAMI input catalog
is based on data taken from the Sloan Digital Sky Survey, the
GAMA Survey and the VST ATLAS Survey. The SAMI
Galaxy Survey is supported by the Australian Research
Council Centre of Excellence for All Sky Astrophysics in 3
Dimensions (ASTRO 3D), through project No. CE170100013,
the Australian Research Council Centre of Excellence for Allsky Astrophysics (CAASTRO), through project No.
CE110001020, and other participating institutions. The SAMI
Galaxy Survey website is http://sami-survey.org/
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