Magnetless circulators based on linear time-varying circuits

In a crowded electromagnetic spectrum with an ever‐increasing demand for higher data rates to enable multimedia‐rich applications and services, an efficient use of the available wireless resources becomes crucial. For this reason, full‐duplex communication, which doubles the transmission rate over a certain bandwidth compared to currently deployed half-duplex radios by operating the uplink and the downlink simultaneously on the same frequency, has been brought back into the spotlight after decades of being presumed impractical. This long‐held assumption has been particularly due to the lack of high performance low-cost and small-size circulators that could mitigate the strong self-interference at the RF frontend interface of full-duplex transceivers while, at the same time, permitting low-loss bi-directional communication using a single antenna. Traditionally, such non-reciprocal components were almost exclusively based on magnetic biasing of rare-earth ferrite materials, which results in bulky and expensive devices that are not suitable for the vast majority of commercial systems. Despite significant research efforts over the past few decades, none of the previous works managed to eliminate the magnet while satisfying all the challenging requirements dictated by the standards of real systems. In this dissertation, we introduce several newly invented magnetless circulators based on linear time-varying circuits that can overcome for the first time the limitations of all previous approaches. We analyze the presented circuits rigorously and validate them through simulations and measurements, showing unprecedented performance in all relevant metrics, thus holding the promise to enable full-duplex radios in the near futur

Progress, pitfalls, and path forward of drug repurposing for COVID-19 treatment

On 30 January 2020, the World Health Organization (WHO) declared the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic a public health emergency of international concern. The viral outbreak led in turn to an exponential growth of coronavirus disease 2019 (COVID-19) cases, that is, a multiorgan disease that has led to more than 6.3 million deaths worldwide, as of June 2022. There are currently few effective drugs approved for treatment of SARS-CoV-2/COVID-19 patients. Many of the compounds tested so far have been selected through a drug repurposing approach, that is, by identifying novel indications for drugs already approved for other conditions. We here present an up-to-date review of the main Food and Drug Administration (FDA)–approved drugs repurposed against SARS-CoV-2 infection, discussing their mechanism of action and their most important preclinical and clinical results. Reviewed compounds were chosen to privilege those that have been approved for use in SARS-CoV-2 patients or that have completed phase III clinical trials. Moreover, we also summarize the evidence on some novel and promising repurposed drugs in the pipeline. Finally, we discuss the current stage and possible steps toward the development of broadly effective drug combinations to suppress the onset or progression of COVID-19

Identification and antibiotic sensitivity of bacteria occasionally isolated from differentiated and undifferentiated cultures of Sinai medicinal plants

Egyptian Journal of Biology Vol.3 2001: 67-7

Trehalose Accumulation in Wheat Plant Promotes Sucrose and Starch Biosynthesis

Abstract Seeds of Triticum aestivum L. (cv. Sakha 93) were sown in pots and grown under controlled conditions in growth chamber. The plants were irrigated with half strength of Hoaglad solution without or with 10 or 30 µM validamycin A, a potent inhibitor of trehalase. Plants were collected at three different stages of growth (17, 24 and 31 DAP). Validamycin A decreased the activity of trehalase which leads to the accumulation of trehalose in shoot and root of wheat plants. Raising trehalose level in the plant tissues was accompanied by increase in the sucrose content and starch content of the shoot. The increased contents in sucrose and starch were mainly attributed to the increased levels of trehalose. The effect of trehalose on the sucrose degrading enzymes (alkaline and acid invertases and sucrose synthase) showed stimulation of alkaline invertase activity and inhibition of acid invertase and sucrose synthase. The opposite behavior of sucrose degrading enzymes suggests a regulation mechanism controlling the sucrose pool