Amino acids act as versatile nutrients driving cell growth and survival, especially in cancer cells. Amino acid metabolism comprises numerous metabolic networks and is closely linked with ...intracellular redox balance and epigenetic regulation. Reprogrammed amino acid metabolism has been recognized as a ubiquitous feature in tumour cells. This review outlines the metabolism of several primary amino acids in cancer cells and highlights the pivotal role of amino acid metabolism in sustaining redox homeostasis and regulating epigenetic modification in response to oxidative and genetic stress in cancer cells.
The interlink between amino acid metabolism and epigenetic regulation. Epigenetic methylation and acetylation might be regulated by amino acid metabolism.
This article considers an artificial noise (AN)-aided secure MIMO wireless communication system. To enhance the system security performance, the advanced intelligent reflecting surface (IRS) is ...invoked, and the base station (BS), legitimate information receiver (IR) and eavesdropper (Eve) are equipped with multiple antennas. With the aim for maximizing the secrecy rate (SR), the transmit precoding (TPC) matrix at the BS, covariance matrix of AN and phase shifts at the IRS are jointly optimized subject to constrains of transmit power limit and unit modulus of IRS phase shifts. Then, the secrecy rate maximization (SRM) problem is formulated, which is a non-convex problem with multiple coupled variables. To tackle it, we propose to utilize the block coordinate descent (BCD) algorithm to alternately update the variables while keeping SR non-decreasing. Specifically, the optimal TPC matrix and AN covariance matrix are derived by Lagrangian multiplier method, and the optimal phase shifts are obtained by Majorization-Minimization (MM) algorithm. Since all variables can be calculated in closed form, the proposed algorithm is very efficient. We also extend the SRM problem to the more general multiple-IRs scenario and propose a BCD algorithm to solve it. Simulation results validate the effectiveness of system security enhancement via an IRS.
In this paper, we investigate the design of robust and secure transmission in intelligent reflecting surface (IRS) aided wireless communication systems. In particular, a multi-antenna access point ...(AP) communicates with a single-antenna legitimate receiver in the presence of multiple single-antenna eavesdroppers, where the artificial noise (AN) is transmitted to enhance the security performance. Besides, we assume that the cascaded AP-IRS-user channels are imperfect due to the channel estimation error. To minimize the transmit power, the beamforming vector at the transmitter, the AN covariance matrix, and the IRS phase shifts are jointly optimized subject to the outage rate probability constraints under the statistical cascaded channel state information (CSI) error model. To handle the resulting non-convex optimization problem, we first approximate the outage rate probability constraints by using the Bernstein-type inequality. Then, we develop a suboptimal algorithm based on alternating optimization, the penalty-based and semidefinite relaxation methods. Simulation results reveal that the proposed scheme significantly reduces the transmit power compared to other benchmark schemes.
The first edition of “Microstrip Filters for RF/Microwave Applications” was published in 2001. Over the years the book has been well received and is used extensively in both academia and industry by ...microwave researchers and engineers. From its inception as a manuscript the book is almost 8 years old. While the fundamentals of filter circuits have not changed, further innovations in filter realizations and other applications have occurred with changes in the technology and use of new fabrication processes, such as the recent advances in RF MEMS and ferroelectric films for tunable filters; the use of liquid crystal polymer (LCP) substrates for multilayer circuits, as well as the new filters for dual-band, multi-band and ultra wideband (UWB) applications. Although the microstrip filter remains as the main transmission line medium for these new developments, there has been a new trend of using combined planar transmission line structures such as co-planar waveguide (CPW) and slotted ground structures for novel physical implementations beyond the single layer in order to achieve filter miniaturization and better performance. Also, over the years, practitioners have suggested topics that should be added for completeness, or deleted in some cases, as they were not very useful in practice. In view of the above, the authors are proposing a revised version of the “Microstrip Filters for RF/Microwave Applications” text and a slightly changed book title of “Planar Filters for RF/Microwave Applications” to reflect the aforementioned trends in the revised book.
Researches were reported that respiratory diseases can lead to male infertility; however, it is unclear whether there is a relationship between pulmonary fibrosis (PF) and male infertility. This ...study examined the influence of PF on sperm quality and its mechanisms. The key signalling pathway of male infertility caused by PF was predicted based on bioinformatics research. After modelling, we evaluated semen quality. Real‐time quantitative polymerase chain reaction and Western blotting were used to measure the protein and mRNA expression levels of phosphatidylinositol 3‐kinase (PI3K), phosphorylation‐protein kinase B (p‐Akt) and B‐cell lymphoma 2 (Bcl2) in rat testicular cells. Compared with group A (48.77 ± 4.67; 59.77 ± 4.79), the sperm concentration and total sperm viability of group B (8.44 ± 1.71; 15.39 ± 3.48) showed a downward trend (p < 0.05). Western blotting showed that the protein expressions of PI3K, p‐Akt and Bcl2 in the testes of group B (0.30 ± 0.06; 0.27 ± 0.05; 0.15 ± 0.03) was significantly lower than those of group A (0.71 ± 0.07; 0.72 ± 0.06; 0.50 ± 0.06) (p < 0.05). The hypoxic environment induced by PF can inhibit the expression of PI3K, p‐Akt and Bcl2 protein and eventually cause dysfunctional spermatogenesis.
A miniature dual-mode microstrip open-loop resonator is proposed. Distinct characteristics of this new type of dual-mode resonator are investigated using full-wave electromagnetic simulations. It is ...shown that the two operating modes, i.e., the even and odd modes, within a single dual-mode resonator of this type do not couple. It is also found that there is a finite-frequency transmission zero inherently associated with the even mode. Two two-pole filters using this type of dual-mode resonator are demonstrated with opposite asymmetric responses, which result from different locations of the transmission zero. Higher order filters of this type are also investigated. Both simulated and measured results are presented.
Covering: 1969 up to 2021
Sesterterpenoids, biosynthetically derived from the precursor, namely geranylfarnesyl diphosphate (GFDP) are amongst the rarest of all isoprenoids with approximately 1300 ...compounds known. Most sesterterpenoids originate from marine organisms (especially sponges), while only about 15% of these compounds are isolated from several families of plants such as Lamiaceae, Gentianaceae, and Nartheciaceae. Many plant sesterterpenoids possess highly oxygenated and complex cyclic skeletons and exhibit remarkable biological activities involving cytotoxic, anti-inflammatory, antimicrobial, and antifeedant properties. Thus, due to their intrinsic chemical complexity and intriguing biological profiles, plant sesterterpenoids have attracted continuing interest from both chemists and biologists. However, the biosynthesis and distribution of sesterterpenoids in the plant kingdom still remain elusive, although substantial progress has been achieved in recent years. This review provides an overall coverage of sesterterpenoids originating from plant sources, followed by a classification of their chemical skeletons, which summarizes the distribution, chemistry, biological activities, biosynthesis and evolution of plant sesterterpenoids, aiming at strengthening the research efforts toward the untapped great potential of these unique natural product resources.
An overall coverage of plant sesterterpenoids including the distribution, chemistry, biological activities, biosynthesis and evolution is provided, highlighting the untapped potential of this enigmatic but promising natural product class in plants.
Study of flexible nanodielectric materials (FNDMs) with high permittivity is one of the most active academic research areas in advanced functional materials. FNDMs with excellent dielectric ...properties are demonstrated to show great promise as energy‐storage dielectric layers in high‐performance capacitors. These materials, in common, consist of nanoscale particles dispersed into a flexible polymer matrix so that both the physical/chemical characteristics of the nanoparticles and the interaction between the nanoparticles and the polymers have crucial effects on the microstructures and final properties. This review first outlines the crucial issues in the nanodielectric field and then focuses on recent remarkable research developments in the fabrication of FNDMs with special constitutents, molecular structures, and microstructures. Possible reasons for several persistent issues are analyzed and the general strategies to realize FNDMs with excellent integral properties are summarized. The review further highlights some exciting examples of these FNDMs for power‐energy‐storage applications.
Recent progress in the development of flexible nanodielectric materials (FNDMs) with high dielectric permittivity is highlighted. Particular focus is given to increasing the energy density of various FNDMs. Key issuses in the synthesis, structure, and dielectric properties of nanodielectrics are reviewed. Some long‐standing problems and topics that warrant further investigation are also addressed.
Abnormal metabolism of tumour cells is closely related to the occurrence and development of breast cancer, during which the expression of NF‐E2‐related factor 2 (Nrf2) is of great significance. ...Metastatic breast cancer is one of the most common causes of cancer death worldwide; however, the molecular mechanism underlying breast cancer metastasis remains unknown. In this study, we found that the overexpression of Nrf2 promoted proliferation and migration of breast cancers cells. Inhibition of Nrf2 and overexpression of Kelch‐like ECH‐associated protein 1 (Keap1) reduced the expression of glucose‐6‐phosphate dehydrogenase (G6PD) and transketolase of pentose phosphate pathway, and overexpression of Nrf2 and knockdown of Keap1 had opposite effects. Our results further showed that the overexpression of Nrf2 promoted the expression of G6PD and Hypoxia‐inducing factor 1α (HIF‐1α) in MCF‐7 and MDA‐MB‐231 cells. Overexpression of Nrf2 up‐regulated the expression of Notch1 via G6PD/HIF‐1α pathway. Notch signalling pathway affected the proliferation of breast cancer by affecting its downstream gene HES‐1, and regulated the migration of breast cancer cells by affecting the expression of EMT pathway. The results suggest that Nrf2 is a potential molecular target for the treatment of breast cancer and targeting Notch1 signalling pathway may provide a promising strategy for the treatment of Nrf2‐driven breast cancer metastasis.
With the wide application of lithium‐ion battery in various fields, the security and reliability of lithium‐ion battery have attracted great attention. Under the mode of continuous development of ...Internet of vehicles technology, vehicles will be connected with each other in the future, and the hackers will attack the energy system of the vehicle. However, health assessment of lithium‐ion battery can timely grasp the running state and health of the power battery system, so as to realize active defense against hacker security attacks. This paper proposes a health assessment method for lithium‐ion batteries using incremental capacity analysis and weighted Kalman filter algorithm. In view of the problem that ordinary Kalman filtering algorithm produces poor filtering results when the actual measurement noise error is large, this paper proposes a weighted Kalman filtering algorithm based on ordinary Kalman filtering. Incremental capacity analysis was performed on the charge and discharge data of lithium‐ion batteries, and health characteristics were extracted to construct a Gaussian nonlinear feature association mapping model for the health characteristics of lithium‐ion batteries. Combined with the battery SOH double‐exponential decay model, the weighted Kalman filter algorithm was used to evaluate the health of lithium‐ion batteries. Four lithium‐ion battery data sets provided by NASA were used to simulate and verify the health assessment method proposed in this paper. The verification results show that the health assessment method based on weighted Kalman filter proposed in this paper has better assessment accuracy than the common Kalman filter method with an average percentage error of 0.61%. The average percentage error of the assessment results for different types of batteries was less than 0.9%. The health assessment method has high accuracy and is suitable for different types of batteries.
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