Flexible nanogenerators that efficiently convert mechanical energy into electrical energy have been extensively studied because of their great potential for driving low‐power personal electronics and ...self‐powered sensors. Integration of flexibility and stretchability to nanogenerator has important research significance that enables applications in flexible/stretchable electronics, organic optoelectronics, and wearable electronics. Progress in nanogenerators for mechanical energy harvesting is reviewed, mainly including two key technologies: flexible piezoelectric nanogenerators (PENGs) and flexible triboelectric nanogenerators (TENGs). By means of material classification, various approaches of PENGs based on ZnO nanowires, lead zirconate titanate (PZT), poly(vinylidene fluoride) (PVDF), 2D materials, and composite materials are introduced. For flexible TENG, its structural designs and factors determining its output performance are discussed, as well as its integration, fabrication and applications. The latest representative achievements regarding the hybrid nanogenerator are also summarized. Finally, some perspectives and challenges in this field are discussed.
Flexible nanogenerators have great potential to be applied in flexible electronics, wearable electronics, implantable electronics, self‐powered sensors, and even for harvesting ocean wave energy. Recent achievements in flexible piezoelectric nanogenerators and flexible triboelectric nanogenerators, in terms of materials, structures, performance, and applications are reviewed. Future perspectives and opportunities in this field are also discussed.
Transparent, flexible and high efficient power sources are important components of organic electronic and optoelectronic devices. In this work, based on the principle of the previously demonstrated ...triboelectric generator, we demonstrate a new high-output, flexible and transparent nanogenerator by using transparent polymer materials. We have fabricated three types of regular and uniform polymer patterned arrays (line, cube, and pyramid) to improve the efficiency of the nanogenerator. The power generation of the pyramid-featured device far surpassed that exhibited by the unstructured films and gave an output voltage of up to 18 V at a current density of ∼0.13 μA/cm2. Furthermore, the as-prepared nanogenerator can be applied as a self-powered pressure sensor for sensing a water droplet (8 mg, ∼3.6 Pa in contact pressure) and a falling feather (20 mg, ∼0.4 Pa in contact pressure) with a low-end detection limit of ∼13 mPa.
The extensive literature review on human epidemiological studies suggests that low dose ionizing radiation (LDIR) (≤100 mSv) or low dose rate ionizing radiation (LDRIR) (<6mSv/H) exposure could ...induce either negative or positive health effects. These changes may depend on genetic background, age (prenatal day for embryo), sex, nature of radiation exposure, i.e., acute or chronic irradiation, radiation sources (such as atomic bomb attack, fallout from nuclear weapon test, nuclear power plant accidents, 60Co-contaminated building, space radiation, high background radiation, medical examinations or procedures) and radionuclide components and human epidemiological experimental designs. Epidemiological and clinical studies show that LDIR or LDRIR exposure may induce cancer, congenital abnormalities, cardiovascular and cerebrovascular diseases, cognitive and other neuropsychiatric disorders, cataracts and other eye and somatic pathology (endocrine, bronchopulmonary, digestive, etc). LDIR or LDRIR exposure may also reduce mutation and cancer mortality rates. So far, the mechanisms of LDIR- or LDRIR -induced health effect are poorly understood. Further extensive studies are still needed to clarify under what circumstances, LDIR or LDRIR exposure may induce positive or negative effects, which may facilitate development of new therapeutic approaches to prevent or treat the radiation-induced human diseases or enhance radiation-induced positive health effect.
•LDIR or LDRIR exposure induces health effects depend on genetic background, age (prenatal day for embryo), sex, nature of radiation exposure.•Epidemiological and clinical studies show that LDIR or LDRIR exposure may induce cancer, congenital abnormalities, vascular diseases, cognitive impairment andcataracts.•LDIR or LDRIR exposure may also reduce mutation and cancer mortality rates.
Harvesting ambient mechanical energy is a key technology for realizing self‐powered electronics, which has tremendous applications in wireless sensing networks, implantable devices, portable ...electronics, etc. The currently reported triboelectric nanogenerator (TENG) mainly uses solid materials, so that the contact between the two layers cannot be 100% with considering the roughness of the surfaces, which greatly reduces the total charge density that can be transferred and thus the total energy conversion efficiency. In this work, a liquid‐metal‐based triboelectric nanogenerator (LM‐TENG) is developed for high power generation through conversion of mechanical energy, which allows a total contact between the metal and the dielectric. Due to that the liquid–solid contact induces large contacting surface and its shape adaptive with the polymer thin films, the LM‐TENG exhibits a high output charge density of 430 μC m−2, which is four to five times of that using a solid thin film electrode. And its power density reaches 6.7 W m−2 and 133 kW m−3. More importantly, the instantaneous energy conversion efficiency is demonstrated to be as high as 70.6%. This provides a new approach for improving the performance of the TENG for special applications. Furthermore, the liquid easily fluctuates, which makes the LM‐TENG inherently suitable for vibration energy harvesting.
A liquid‐metal‐based triboelectric nanogenerator (LM‐TENG) is developed for high power generation through conversion of mechanical energy, which allows total contact between the metal and the dielectric. The LM‐TENG exhibits a high output charge density of 430 μC m−2, which is four to five times of that using a solid thin film electrode. An instantaneous energy conversion efficiency as high as 70.6% is demonstrated.
Plasmonic metals under photoexcitation can generate energetic hot electrons to directly induce chemical reactions. However, the capability and fundamental insights of the transportation of these hot ...electrons at plasmonic metal‐2D material interfaces remain unclear. Herein, hot‐electron transfer at Au‐graphene interfaces has been in situ studied using surface‐enhanced Raman spectroscopy (SERS) with atomic layer accuracy. Combining in situ SERS studies with density functional theory calculations, it is proved that hot electrons can be injected from plasmonic Au nanoparticles to graphene and directly penetrate graphene to trigger photocatalytic reactions. With increasing graphene layers, the transportation of hot electrons decays rapidly and would be completely blocked after five layers of graphene. Moreover, the transfer of hot electrons can be modulated by applying an external electric field, and the hot‐electron transfer efficiency under electrochemical conditions is improved by over three times in the presence of a monolayer of graphene.
Hot‐electron transfer at Au–graphene interfaces has been investigated in situ with atomic layer accuracy, and it is shown that hot electrons can be injected from plasmonic Au nanoparticles to graphene and penetrate up to four layers of graphene.
Charges induced in triboelectric process are usually referred as a negative effect either in scientific research or technological applications, and they are wasted energy in many cases. Here, we ...demonstrate a simple, low cost and effective approach of using the charging process in friction to convert mechanical energy into electric power for driving small electronics. The triboelectric generator (TEG) is fabricated by stacking two polymer sheets made of materials having distinctly different triboelectric characteristics, with metal films deposited on the top and bottom of the assembled structure. Once subjected to mechanical deformation, a friction between the two films, owing to the nano-scale surface roughness, generates equal amount but opposite signs of charges at two sides. Thus, a triboelectric potential layer is formed at the interface region, which serves as a charge “pump” for driving the flow of electrons in the external load if there is a variation in the capacitance of the system. Such a flexible polymer TEG gives an output voltage of up to 3.3V at a power density of ∼10.4mW/cm3. TEGs have the potential of harvesting energy from human activities, rotating tires, ocean waves, mechanical vibration and more, with great applications in self-powered systems for personal electronics, environmental monitoring, medical science and even large-scale power.
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► Using the charging process in friction to convert mechanical energy into electric power. ► The triboelectric generator (TEG) is entirely based on polymer. ► Harvesting energy from human activities, rotating tires and mechanical vibration.
SUMMARY
Low phosphate (LP) in soil is a common nutrient stress that severely restricts agricultural production, but the role, if any, of the major stress phytohormone abscisic acid (ABA) in plant ...phosphate (Pi) starvation responses remains elusive. Here, we report that LP‐induced ABA accumulation promotes Pi uptake in an ABA INSENSITIVE5 (ABI5)‐dependent manner in Arabidopsis thaliana. LP significantly activated plant ABA biosynthesis, metabolism, and stress responses, suggesting a role of ABA in the plant response to Pi availability. LP‐induced ABA accumulation and expression of two major high‐affinity phosphate transporter genes PHOSPHATE TRANSPORTER1;1/1;4 (PHT1;1/1;4) were severely impaired in a mutant lacking BETA‐GLUCOSIDASE1 (BG1), which converts conjugated ABA to active ABA, and the mutant had shorter roots and less Pi content than wild‐type plants under LP conditions. Moreover, a mutant of ABI5, which encodes a central transcription factor in ABA signaling, also exhibited suppressed root elongation and had reduced Pi content under LP conditions. ABI5 facilitated Pi acquisition by activating the expression of PHT1;1 by directly binding to its promoter, while overexpression of PHT1;1 completely rescued its Pi content under LP conditions. Together, our findings illustrate a molecular mechanism by which ABA positively modulates phosphate acquisition through ABI5 in the Arabidopsis response to phosphate deficiency.
Significance Statement
Low phosphate (LP) is a common nutrient stress that severely suppresses plant growth and development, while whether and how the major stress phytohormone abscisic acid (ABA) functions in plant phosphate (Pi) starvation responses remains elusive. Our study showed that LP‐induced ABA promotes Pi uptake by activating PHOSPHATE TRANSPORTER1;1 expression in an ABA INSENSITIVE5‐dependent manner in Arabidopsis thaliana under LP.
Berberine plays a neuro-protective role in neurodegenerative diseases, including Parkinson’s disease (PD). Long non-coding RNAs (lncRNAs) play critical roles in PD pathogenesis. The purpose of this ...study was to investigate whether LINC00943 was involved in the role of berberine in PD. 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) or 1-methyl-4-phenyl pyridine (MPP
+
) were used to construct PD mouse and cell models
,
respectively. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2’-deoxyuridine (Edu) assays. Inflammation and cell apoptosis were assessed by enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively. Quantitative real-time PCR (qRT-PCR) was employed to test the expression of LINC00943, microRNA (miR)-142-5p, and karyopherin subunit alpha 4 (KPNA4) mRNA. The protein levels of NF-κB pathway-related markers and KPNA4 were measured by western blot. Oxidative stress level was assessed by corresponding kits. The interaction between miR-142-5p and LINC00943 or KPNA4 was determined via dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Berberine inhibited MPP
+
-induced injury in SK-N-SH cells by promoting cell proliferation and suppressing inflammation, apoptosis, and oxidative injury. LINC00943 and KPNA4 were upregulated and miR-142-5p was downregulated in PD mouse and cell models. LINC00943 (or KPNA4) overexpression or miR-142-5p inhibition abated the neuro-protective role of berberine in PD cell model. Moreover, miR-142-5p was a target of LINC00943, and KPNA4 could specially bind to miR-142-5p. Additionally, berberine inhibited NF-κB pathway by regulating LINC00943/miR-142-5p/KPNA4 axis. Berberine protected SK-N-SH cell from MPP
+
-induced neuronal damage via regulating LINC00943/miR-142-5p/KPNA4/NF-κB pathway, highlighting novel evidence for the neuro-protective role of berberine in PD.
Abstract
Objectives
Chamomile has long been used as a medicinal plant due to its antioxidative and anti-inflammatory activity. Apigenin-7-O-glucoside (AG) is one of the major ethanol extract ...components from chamomile; however, the underlying mechanism remains unclear.
Methods
In this study, the antioxidant potential and the anti-inflammatory activities of AG were analysed and compared with those of trolox. We demonstrate the protective effects of AG on free radical-induced oxidative damage of DNA, proteins and erythrocytes. Flow cytometry assay was used to detect ROS production. Additionally, the expression of anti-oxidation-related and inflammation-related factors was detected by ELISA and Western blotting, respectively.
Key findings
AG and trolox showed different efficiency as antioxidant in different experimental systems. AG had similar effect as trolox to inhibit H2O2-induced ROS production in RAW264.7 cells, while exerted stronger inhibition against free radical-induced oxidative damage on erythrocytes than trolox. Interestingly, compared with trolox, AG also had stronger inhibitory effect on LPS-induced NF-κB/NLRP3/caspase-1 signalling in RAW246.7 cells.
Conclusions
These results suggest the potential of AG as a pharmaceutical drug for anti-oxidation and anti-inflammation, and the combined usage of AG and trolox might promote its efficacy. Our findings will provide new insights into the development of new drugs with antioxidative and anti-inflammatory functions.
In this work, exfoliated graphite nanoplates (xGNPs)/thermoplastic polyurethane (TPU) composites with enhanced dielectric constant and relatively low dielectric loss factor were prepared by an ...effective method involving solution blending and water precipitating. The wide-angle X-ray diffraction results proved that the xGNPs had been added into the TPU. Furthermore, the microstructure of the resultant xGNPs (2 wt.%)/TPU composite was investigated by scanning electron microscopy (SEM). The SEM images showed that there were many xGNPs in the TPU elastomer matrix. According to differential scanning calorimetry the melting peak temperature and the crystallization peak temperature of the xGNPs/TPU composites were lower than those of the pure TPU but the melting enthalpy and the crystallization enthalpy of the xGNPs/TPU composites were higher than those of the pure TPU. More importantly, the dielectric constant at 1000 Hz and the thermal conductivity of the xGNPs/TPU composites obviously increased in comparison with those of the pure TPU, especially when the xGNPs content was 2 wt.%.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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