Reconfigurable intelligent surface (RIS)‐empowered communications is on the rise and is a promising technology envisioned to aid in 6G and beyond wireless communication networks. RISs can manipulate ...impinging waves through their electromagnetic elements enabling some sort of control over the wireless channel. The potential of RIS technology is explored to perform a sort of virtual equalization over‐the‐air for frequency‐selective channels, whereas equalization is generally conducted at either the transmitter or receiver in conventional communication systems. Specifically, using an RIS, the frequency‐selective channel from the transmitter to the RIS is transformed to a frequency‐flat channel through elimination of inter‐symbol interference (ISI) components at the receiver. ISI is eliminated by adjusting the phases of impinging signals particularly to maximize the incoming signal of the strongest tap. First, a general end‐to‐end system model is provided and a continuous to discrete‐time signal model is presented. Subsequently, a probabilistic analysis for elimination of ISI terms is conducted and reinforced with computer simulations. Furthermore, a theoretical error probability analysis is performed along with computer simulations. It is analysed and demonstrated that conventional RIS phase alignment methods can successfully eliminate ISI, and the RIS‐aided communication channel can be converted from frequency‐selective to frequency‐flat.
Reconfigurable intelligent surface (RIS)-assisted communication have recently attracted the attention of the wireless communication community as a potential candidate for the next 6-th generation ...(6G) of wireless networks. Various studies have been carried out on the RIS technology, which is capable of enabling the control of the signal propagation environment by network operators. However, when an RIS is used in its inherently passive structure, it appears to be only a supportive technology for communications, while suffering from a multiplicative path loss. Therefore, researchers have lately begun to focus on RIS hardware designs with minimal active elements to further boost the benefits of this technology. In this paper, we present a simple RIS hardware architecture including a single and variable gain amplifier for reflection amplification to confront the multiplicative path loss. The end-to-end signal model for communication systems assisted with the proposed amplifying RIS design is presented, together with an analysis focusing on the capacity maximization and theoretical bit error probability performance, which is corroborated by computer simulations. In addition, the major advantages of the proposed amplifying RIS design compared to its passive counterpart are discussed. It is shown that the proposed RIS-based wireless system significantly eliminates the double fading problem appearing in conventional passive RIS-assisted systems and improves the communication energy efficiency.
The double stent-assisted techniques for the treatment of wide neck bifurcation aneurysms (WNBAs) may be more complicating than single stent-assisted or balloon-assisted coiling. The Comaneci device ...(Rapid Medical, Yokneam, Israel) is a new temporary bridging device developed for covering the aneurysm neck during coiling. This new design enabled us to treat unruptured WNBAs with the use of single stent-assisted coiling instead of double stent in eight patients. At the 1-year angiographic follow-up, there was no filling in any aneurysm. There was no mortality or morbidity cases related to the procedure. In this study, we are reporting our experience of using single stent-assisted coiling combined with a Comaneci device in the treatment of unruptured WNBAs.
Reconfigurable intelligent surface (RIS)-assisted communication appears as one of the potential enablers for sixth generation (6G) wireless networks by providing a new degree of freedom in the system ...design to telecom operators. Particularly, RIS-empowered millimeter wave (mmWave) communication systems can be a remedy to provide broadband and ubiquitous connectivity. This paper aims to fill an important gap in the open literature by providing a physical, accurate, open-source, and widely applicable RIS channel model for mmWave frequencies. Our model is not only applicable in various indoor and outdoor environments but also includes the physical characteristics of wireless propagation in the presence of RISs by considering 5G radio channel conditions. Various deployment scenarios are presented for RISs and useful insights are provided for system designers from the perspective of potential RIS use-cases and their efficient positioning. The scenarios in which the use of an RIS makes a big difference or might not have a big impact on the communication system performance, are revealed. The open-source and comprehensive SimRIS Channel Simulator is also introduced in this paper.
In this letter, we introduce two hybrid transmission schemes combining a passive reconfigurable intelligent surface (RIS) with decode-and-forward relaying in a synergistic manner. The proposed ...schemes offer a flexible as well as cost-and power-efficient solution for coverage extension in future generation wireless networks. We present closed-form expressions for the end-to-end signal-to-noise ratio of both schemes and a sequential optimization algorithm for the power allocation and the RIS phase configurations. Our computer simulations and theoretical analysis demonstrate that the RIS and relaying technologies enhance the achievable rate and error performance remarkably when working complementary to each other, rather than being considered as competing technologies.
We investigated the association between National Institute of Health category IV prostatitis and prostate-specific antigen levels in patients with low-risk localized prostate cancer.
The data of 440 ...patients who had undergone prostate biopsies due to high PSA levels and suspicious digital rectal examination findings were reviewed retrospectively. The patients were divided into two groups based on the presence of accompanying NIH IV prostatitis. The exclusion criteria were as follows: Gleason score>6, PSA level>20ng/mL, >2 positive cores, >50% cancerous tissue per biopsy, urinary tract infection, urological interventions at least 1 week previously (cystoscopy, urethral catheterization, or similar procedure), history of prostate biopsy, and history of androgen or 5-alpha reductase use. All patient's age, total PSA and free PSA levels, ratio of free to total PSA, PSA density and prostate volume were recorded.
In total, 101 patients were included in the study. Histopathological examination revealed only PCa in 78 (77.2%) patients and PCa+NIH IV prostatitis in 23 (22.7%) patients. The median total PSA level was 7.4 (3.5-20.0) ng/mL in the PCa+NIH IV prostatitis group and 6.5 (0.6-20.0) ng/mL in the PCa group (p=0.67). The PSA level was≤10ng/mL in 60 (76.9%) patients in the PCa group and in 16 (69.6%) patients in the PCa+NIH IV prostatitis group (p=0.32).
Our study showed no statistically significant difference in PSA levels between patients with and without NIH IV prostatitis accompanying PCa.
The cultivated oat (Avena sativa L. and A. byzantina Coch.) is an important annual cereal and forage plant. A large collection of historical oat landraces gathered from different diversity centers is ...maintained in various seed banks. A historical oat collection consisted of 174 Turkish landraces were evaluated for agronomic performance and mineral nutrient content. The experiment was arranged in an augmented design with six replications of 10 check cultivars and 29 landraces in each block. The most important finding of the study was that the landraces manifested a wide range of variation in all agronomic traits and that some historical landraces outperformed the check cultivars. Since it was dry for the grain‐filling period (GFP) in 2019, some drought‐tolerant landraces were identified. In addition, the top 10 landraces for yield and mineral content were also identified based on each year's performance as well as on the 3‐yr average. The landrace TL69/PI411401 was found to be prominent for high calcium (Ca), magnesium (Mg), phosphorus (P), boron (B), and zinc (Zn) content; TL86/PI167378 for Ca, P, potassium (K), and iron (Fe) contents; and TL71/PI411414 for Ca, P, B, and Zn content.
Core Ideas
Agronomic performance and minerals content of 174 landraces from Turkey were evaluated.
Oat landraces manifested a wide range of variation, and some perform higher than check cultivars.
Grain‐filling period was dry in the 2019 growing season revealing a set of drought‐tolerant oat landraces.
The panel of 174 oat landraces evaluated here indicated to be an important genetic resource for oat breeding.
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