35 research outputs found
Adopting mobile internet: a demographic and usage perspective
No full textBased on an online survey of American consumers, the author found that mobile internet adopters tended to be younger, non-Caucasian, lower income, single male with higher career mobility. Surprisingly, contrary to fixed internet adoption, education played no significant role in predicting mobile internet adoption. Heavy mobile phone users were more likely to adopt mobile internet. On the opposite, heavy fixed internet users were less likely to adopt mobile internet. Interestingly, the demographics and usage patterns of consumers who perceived higher importance of having mobile internet capabilities did not match those of who indicated higher likelihood of adopting mobile internet
Reduced Lattice Thermal Conductivity for Half-Heusler ZrNiSn through Cryogenic Mechanical Alloying
No full textBahrami A, Ying P, Wolff U, et al. Reduced Lattice Thermal Conductivity for Half-Heusler ZrNiSn through Cryogenic Mechanical Alloying. ACS applied materials & interfaces. 2021;13(32):38561–38568.The ZrNiSn-based half-Heusler compounds are promising for thermoelectric applications in the mid-to-high temperature range. However, their thermoelectric performance was greatly limited due to the remaining high thermal conductivity, especially the lattice thermal conductivity. Herein, we report the synthesis of pristine half-Heusler ZrNiSn through direct mechanical alloying at a liquid nitrogen temperature (i.e., cryomilling) followed by spark plasma sintering. It is shown that the onset sintering temperature is greatly reduced for the cryomilled powders with a high density. A reduced thermal conductivity is subsequently realized from room temperature to 700 °C in the cryomilled samples than the one that was differently prepared (from 7.3 to 4.5 W/m K at room temperature). The pronounced reduction in thermal conductivity of ZrNiSn yields a maximum zT of 0.65 at 700 °C. Our study shows the possibility of cryomilling in advancing the thermoelectric performance through enhanced phonon scattering
Towards tellurium-free thermoelectric modules for power generation from low-grade heat.
No full textYing P, He R, Mao J, et al. Towards tellurium-free thermoelectric modules for power generation from low-grade heat. Nature communications. 2021;12(1): 1121.Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Commercial thermoelectric modules have relied on Bi2Te3-based compounds because of their unparalleled thermoelectric properties at temperatures associated with low-grade heat (<550K). However, the scarcity of elemental Te greatly limits the applicability of such modules. Here we report the performance of thermoelectric modules assembled from Bi2Te3-substitute compounds, including p-type MgAgSb and n-type Mg3(Sb,Bi)2, by using a simple, versatile, and thus scalable processing routine. For a temperature difference of ~250K, whereas a single-stage module displayed a conversion efficiency of ~6.5%, a module using segmented n-type legs displayed a record efficiency of ~7.0% that is comparable to the state-of-the-art Bi2Te3-based thermoelectric modules. Our work demonstrates the feasibility and scalability of high-performance thermoelectric modules based on sustainable elements for recovering low-grade heat
Melatonin-Induced Protective Effects on Cardiomyocytes Against Reperfusion Injury Partly Through Modulation of IP3R and SERCA2a Via Activation of ERK1
No full textMelatonin-Induced Protective Effects on Cardiomyocytes Against Reperfusion Injury Partly Through Modulation of IP3R and SERCA2a Via Activation of ERK1
No full textResumo Background: Melatonin is a neuroendocrine hormone synthesized primarily by the pineal gland that is indicated to effectively prevent myocardial reperfusion injury. It is unclear whether melatonin protects cardiac function from reperfusion injury by modulating intracellular calcium homeostasis. Objective: Demonstrate that melatonin protect against myocardial reperfusion injury through modulating IP3R and SERCA2a to maintain calcium homeostasis via activation of ERK1 in cardiomyocytes. Methods: In vitro experiments were performed using H9C2 cells undergoing simulative hypoxia/reoxygenation (H/R) induction. Expression level of ERK1, IP3R and SERCA2a were assessed by Western Blots. Cardiomyocytes apoptosis was detected by TUNEL. Phalloidin-staining was used to assess alteration of actin filament organization of cardiomyocytes. Fura-2 /AM was used to measure intracellular Ca2+ concentration. Performing in vivo experiments, myocardial expression of IP3R and SERCA2a were detected by immunofluorescence staining using myocardial ischemia/ reperfusion (I/R) model in rats. Results: In vitro results showed that melatonin induces ERK1 activation in cardiomyocytes against H/R which was inhibited by PD98059 (ERK1 inhibitor). The results showed melatonin inhibit apoptosis of cardiomyocytes and improve actin filament organization in cardiomyocytes against H/R, because both could be reversed by PD98059. Melatonin was showed to reduce calcium overload, further to inhibit IP3R expression and promote SERCA2a expression via ERK1 pathway in cardiomyocytes against H/R. Melatonin induced lower IP3R and higher SERCA2a expression in myocardium that were reversed by PD98059. Conclusion: melatonin-induced cardioprotection against reperfusion injury is at least partly through modulation of IP3R and SERCA2a to maintain intracellular calcium homeostasis via activation of ERK1
Tuning Multiscale Microstructures to Enhance Thermoelectric Performance of n‐Type Bismuth‐Telluride‐Based Solid Solutions
No full textMelatonin-Induced Protective Effects on Cardiomyocytes Against Reperfusion Injury Partly Through Modulation of IP3R and SERCA2a Via Activation of ERK1
No full textResumo Background: Melatonin is a neuroendocrine hormone synthesized primarily by the pineal gland that is indicated to effectively prevent myocardial reperfusion injury. It is unclear whether melatonin protects cardiac function from reperfusion injury by modulating intracellular calcium homeostasis. Objective: Demonstrate that melatonin protect against myocardial reperfusion injury through modulating IP3R and SERCA2a to maintain calcium homeostasis via activation of ERK1 in cardiomyocytes. Methods: In vitro experiments were performed using H9C2 cells undergoing simulative hypoxia/reoxygenation (H/R) induction. Expression level of ERK1, IP3R and SERCA2a were assessed by Western Blots. Cardiomyocytes apoptosis was detected by TUNEL. Phalloidin-staining was used to assess alteration of actin filament organization of cardiomyocytes. Fura-2 /AM was used to measure intracellular Ca2+ concentration. Performing in vivo experiments, myocardial expression of IP3R and SERCA2a were detected by immunofluorescence staining using myocardial ischemia/ reperfusion (I/R) model in rats. Results: In vitro results showed that melatonin induces ERK1 activation in cardiomyocytes against H/R which was inhibited by PD98059 (ERK1 inhibitor). The results showed melatonin inhibit apoptosis of cardiomyocytes and improve actin filament organization in cardiomyocytes against H/R, because both could be reversed by PD98059. Melatonin was showed to reduce calcium overload, further to inhibit IP3R expression and promote SERCA2a expression via ERK1 pathway in cardiomyocytes against H/R. Melatonin induced lower IP3R and higher SERCA2a expression in myocardium that were reversed by PD98059. Conclusion: melatonin-induced cardioprotection against reperfusion injury is at least partly through modulation of IP3R and SERCA2a to maintain intracellular calcium homeostasis via activation of ERK1.</div
Hierarchical Chemical Bonds Contributing to the Intrinsically Low Thermal Conductivity in α‐MgAgSb Thermoelectric Materials
No full textThermal stability studies on Cu-contacted Mg2X-based solid solutions (X=Si,Sn) in high temperature region
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