Pyruvate kinase M2 at a glance Yang, Weiwei; Lu, Zhimin
Journal of cell science,
05/2015, Letnik:
128, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Reprogrammed metabolism is a key feature of cancer cells. The pyruvate kinase M2 (PKM2) isoform, which is commonly upregulated in many human cancers, has been recently shown to play a crucial role in ...metabolism reprogramming, gene transcription and cell cycle progression. In this Cell Science at a glance article and accompanying poster, we provide a brief overview of recent advances in understanding the mechanisms underlying the regulation of PKM2 expression, enzymatic activity, metabolic functions and subcellular location. We highlight the instrumental role of the non-metabolic functions of PKM2 in tumorigenesis and evaluate the potential to target PKM2 for cancer treatment.
Highlights • PKM2 functions as a protein kinase to regulate gene expression. • PKM2 but not PKM1 translocates into the nucleus upon growth factor stimulation. • Nuclear PKM2 promotes growth ...factor-induced Warburg effect.
As one of emerging contaminants, microplastics (MPs) can enter the environment and adsorb toxic metals such as cadmium (Cd), thereby causing potential environmental risks. However, adsorption ...characteristics of MPs are poorly understood. Herein, batch experiments were performed to investigate the adsorption characteristics of Cd onto high-density polyethylene (HDPE) MPs with different particle sizes, that is, 1–2 mm, 0.6–1 mm, and 100–154 μm. The adsorption of Cd was quite rapid initially, and the equilibrium time was approximately 90 min. An increase in the pH of the Cd solution led to an increase in Cd adsorption. MPs with particle size of 100–154 μm had the highest adsorption capacity. Addition of 1, 10, and 100 mg/L NaCl all significantly decreased Cd adsorption. Adsorption kinetics fitted the pseudo-second-order model. Adsorption isotherm followed the Langmuir model and, to a lesser extent, the Freundlich model, with estimated maximum adsorption capacity of 30.5 μg/g. The adsorbed Cd easily desorbed from the MPs. Energy-dispersive X-ray spectroscopy (EDS) analysis confirmed Cd adsorption to and desorption from MPs. Fourier transform infrared (FTIR) spectroscopy analysis showed no new functional groups formed during the adsorption and desorption processes, suggesting physical interaction may dominate the Cd adsorption onto MPs. The present study findings provide evidence that MPs can accumulate Cd, and the adsorbed Cd may be highly available, thus posing risks to the organisms exposed to these MPs.
Display omitted
•Adsorption of Cd was initially very rapid and then reached equilibrium within 90 min.•Increasing the pH of Cd solution led to an increase in Cd adsorption.•Microplastics with a smaller particle size showed higher adsorption capacity.•Addition of NaCl decreased Cd adsorption by microplastics.•The adsorbed Cd was easily desorbed from the microplastics.
This paper investigates physical layer security (PLS) in cognitive radio inspired non-orthogonal multiple access (CR-NOMA) networks with multiple primary and secondary users. To manage the ...interferences among the users and guarantee the quality of services of primary users, a new secure NOMA transmission strategy is designed, where the primary and secondary users are paired according to their channel gains, respectively, and power-domain NOMA is employed to transmit the signal. Then, the closed-form expressions for connection outage probability, secrecy outage probability, and effective secrecy throughput are derived for the primary users over Nakagami-<inline-formula><tex-math notation="LaTeX">m</tex-math></inline-formula> fading channels when the secondary users are considered as eavesdroppers. Typically, the secrecy performance can be improved by pairing the primary users with best channel gains or reducing the number of secondary users. In addition, we also investigate the performances of secondary users by deriving the closed-form expressions for throughput of secondary network. Furthermore, simulations are conducted to verify our analysis results and provide insights into the impact of the parameters on system performance.
Display omitted
Developing an effective photocatalytic denitrification technology for NO3− and NO2− in water is urgently needed. In this paper, we synthesized a nitrogen-rich g-C3N4, and in-situ ...grown AgPd nanowires (NWs) on the surface of nitrogen-rich g-C3N4 to build AgyPd10−y/g-CxN4 Mott-Schottky heterojunction. Compared with g-CxN4, AgyPd10−y/g-CxN4 exhibits the enhanced photocatalytic hydrogen production from water and tandem reduction of NO3− and NO2− without the addition of other hydrogen source under 365 nm irradiation. The catalytic activity and selectivity of AgyPd10−y/g-CxN4 were studied by combination of the nitrogen-rich g-C3N4 and the different component of AgyPd10−y nanowires (NWs). Among the AgyPd10−y/g-CxN4 catalyst, the Ag3Pd7/g-C1.95N4 catalyst exhibited the highest photocatalytic activity and selectivity for photocatalytic reduction of NO3− and NO2−, and the removal rate of NO3− and NO2− are 87.4% and 61.8% under 365 nm irradiation at 25 °C, respectively. The strategy opens a new way for making the photocatalytic hydrogen production in tandem with reduction of NO3− and NO2− in water, also extending it to remove metal ion.
Display omitted
•CoS2/g-C3N4-rGO composites were rationally prepared by a facile one-pot method.•Cr(VI) was efficiently removed by CoS2/g-C3N4-rGO under visible-light irradiation.•CoS2/g-C3N4-rGO ...dramatically increased the electron-hole separation.•The introduction of rGO effectively inhibited the agglomeration of CoS2 NPs.•CoS2/g-C3N4-rGO exhibited a superior photocatalysis/adsorption synergy.
There is an increasingly significant issue on Cr(VI) pollution in chemical industry and environmental protection. In this study, we have successfully synthesized CoS2/g-C3N4-rGO hybrid nanocomposites via a simple one-pot solvothermal method as an effective photocatalyst. The CoS2/g-C3N4 heterostructure on rGO showed improved photocatalytic performance for Cr(VI) reduction during visible light irradiation. The optimized photocatalyst shows the 99.8% reduction efficiency for Cr(VI) within 120 min at pH = 2 and still exhibits more than 98% removal efficiency after 5 cycles at the same condition. The enhanced photocatalytic performance of the hybrid nanocomposites can be assigned to the enhanced utilizationof visible light arising from the coupling effect in the hybrid nanocomposites and more effective electron-hole pairs separation in heterostructure junction, and large specific surface area and more exposing active sites of CoS2 dispersed on rGO. This study provides a new method to develop high-efficiency photocatalysts for Cr(VI) removal.
The Triassic Chang 7 Formation is a rich lacustrine source rock in the Ordos Basin, central China. Petrographic and geochemical analyses were performed in order to research the mechanism of organic ...matter (OM) enrichment in the Chang 7 shales. Bulk geochemical data indicate that the OM-rich shales were formed in a fresh and brackish water, which is not usually the case for high TOC (Total Organic Carbon Content) sediments. Therefore, there must be some special conditions favorable for OM enrichment in Chang 7 shales.
Petrography and element geochemistry show that the Chang 7 OM-rich shales are abundant in OM-enriched laminae, framboidal pyrites, collophanes, and some elements including iron (Fe), diphosphorus pentoxide (P2O5), copper (Cu), vanadium (V), molybdenum (Mo), and uranium (U). High bio-productivity (algae blooming) and anoxic depositional environments are critical for OM enrichment. As the organic carbon contents increase, the Fe, P2O5, Cu, V, Mo, and U element contents increase as well and the ratios of U/Th and V/(V+Ni) are growing. Many geochemical data demonstrate that the water was oxic, while the environment under the sediment-water interface was anoxic as a result of a high organic supply that sufficiently consumed oxygen.
Taking into account the geological settings and our previous studies, we propose that the frequent volcanic events and hydrothermal activity caused by the collision of the North China landmass with the Yangtze landmass and consequential formation of the Qingling Mountains had a significant role in the OM enrichment in the fresh and brackish lacustrine shales. Deposition of volcanic ash into aqueous environments might lead to the increase of some key nutrients, such as Fe and P2O5, which might enhance primary bio-productivity. New evidence for hydrothermal activity, the reddingite, was demonstrated in this study. Not only can the hydrothermal activity provide elements necessary for life, but is also favorable for formation of anoxic settings.
The deposition of the Chang 7 lacustrine OM-rich shales can be explained using the High-Bio-Productivity-Driven Model, which is related to volcanic events and hydrothermal activity as a consequence of regional tectonic movements. An anoxic depositional setting is beneficial for OM preservation and slow sedimentation rates in the deep lacustrine environments are favorable for OM enrichment.
Display omitted
•The sediment-water interface may be the oxic-anoxic interface.•A high-productivity-driven model was proposed.•Triggers for high nutrient in-flux may be volcanic events and hydrothermal activities.
The insights on the primary active oxygen specie and its relation with oxygen vacancy is essential for the design of low-temperature oxidation catalysts. Herein, oxygen vacancy-rich La0.8Sr0.2CoO3 ...with an ordered macroporous structure was integrated on the commercial ceramic monolith in large scale without additional adhesives via a facile in situ solution assembly. The constructed macropores not only contributed to the oxygen vacancy generation in catalyst preparation but also facilitated favorable mass transport during catalytic process. Combined with theoretical investigations and EPR, O2-TPD, H2-TPR observations, we revealed that monatomic oxygen ions (O–) are the primary oxygen active specie for perovskite oxide. And molecular O2 is more favorably adsorbed and activated on surface oxygen vacancies via a one electron transfer process to form monatomic oxygen ions (O–), thus boosting richness of active O– and the low-temperature oxidation of CO. Different with the preferential Eley–Rideal (E-R) mechanism on pristine LSCO surface, Langmuir–Hinshelwood (L-H) mechanism, in which O– reacts with adsorbed CO to finish the oxidation reaction, was more favorable on the oxygen vacancy rich surface. Our work here elucidates the primary active oxygen specie as well as its origin over perovskite oxides and paves a feasible pathway for rational design of high-performance catalysts in heterogeneous reactions.
We enhance the physical layer security (PLS) of amplify-and-forward (AF) relaying networks with the aid of joint relay and jammer selection (JRJS), despite the deleterious effect of channel state ...information (CSI) feedback delays. Furthermore, we conceive a new outage-based characterization approach for the JRJS scheme. The traditional best relay selection (TBRS) is also considered as a benchmark. We first derive closed-form expressions of both the connection outage probability (COP) and the secrecy outage probability (SOP) for both the TBRS and JRJS schemes. Then, a reliable and secure connection probability (RSCP) is defined and analyzed for characterizing the effect of the correlation between the COP and the SOP introduced by the corporate source-relay link. The reliability-security ratio (RSR) is introduced for characterizing the relationship between the reliability and the security through asymptotic analysis. Moreover, the concept of effective secrecy throughput is defined as the product of the secrecy rate and of the RSCP for the sake of characterizing the overall efficiency of the system, as determined by the transmit SNR, the secrecy codeword rate, and the power sharing ratio between the relay and the jammer. The impact of the direct source-eavesdropper link and additional performance comparisons with respect to other related selection schemes are also included. Our numerical results show that the JRJS scheme outperforms the TBRS method both in terms of the RSCP and in terms of its effective secrecy throughput, but it is more sensitive to the feedback delays. Increasing the transmit signal-to-noise ratio (SNR) will not always improve the overall throughput. Moreover, the RSR results demonstrate that, upon reducing the CSI feedback delays, the reliability improves more substantially than the security degrades, implying an overall improvement in terms of the security-reliability tradeoff. Additionally, the secrecy throughput loss due to the second-hop feedback delay is more pronounced than that due to the first-hop one.
The Internet of Things (IoT) is expected to provide ubiquitous wireless machine-type communication devices and extensive information collection, resulting in an unprecedented amount of privacy and ...secrets exposed to the radio space. Security issues become a major restriction on the further development of IoT. However, secure transmissions in IoT are challenged by low complexity limitation and massive connectivity demand, especially by the use of short packets, which are expected to satisfy the delay requirement in ultra-reliable low-latency communications. Physical layer security can be employed without the constraints of packet length and number of connections. Nevertheless, due to the limitations of complexity, not all existing PLS techniques can be adopted in IoT. Non-orthogonal multiple access (NOMA) is a promising technique for increasing connectivity and reducing delay. Assuming an eavesdropper (Eve) is capable of the same detection capability as legitimate users, this article further exploits the inherent characteristics of NOMA to secure short-packet communications in IoT networks without introducing extra security mechanisms. Both downlink and uplink NOMA schemes are introduced to secure transmission by deliberately increasing the co-channel interference at Eve, which can be viewed as a special cooperative jamming strategy. Simulations show that in both uplink and downlink, although secrecy performance deteriorates in short-packet communications, the performance gains of NOMA over traditional orthogonal multiple access are significant. Finally, we analyze the challenges and future trends in this emerging area.
PDF
