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This paper proposes a compact Thévenin model for a rectenna. This model is then applied to design a high-efficiency radio frequency harvester with a maximum power point tracker (MPPT). The rectenna under study consists of an L-matching network and a half-wave rectifier. The derived model is simpler and more compact than those suggested so far in the literature and includes explicit expressions of the Thévenin voltage () and resistance and of the power efficiency related with the parameters of the rectenna. The rectenna was implemented and characterized from -30 to -10 dBm at 808 MHz. Experimental results agree with the proposed model, showing a linear current⁻voltage relationship as well as a maximum efficiency at /2, in particular 60% at -10 dBm, which is a remarkable value. An MPPT was also used at the rectenna output in order to automatically work at the maximum efficiency point, with an overall efficiency near 50% at -10 dBm. Further tests were performed using a nearby transmitting antenna for powering a sensor node with a power consumption of 4.2 µW.
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http://dx.doi.org/10.3390/s19071641 | DOI Listing |
Diabetol Metab Syndr
August 2025
Department of Infectious Disease, the First Affiliated Hospital of Jinan University, Guangzhou, 510630, China.
Background: Non‑alcoholic fatty liver disease (NAFLD) is characterized by excessive hepatic fat accumulation and is closely associated with inflammation and metabolic dysregulation. The C‑reactive protein-albumin-lymphocyte (CALLY) index, a composite marker of inflammation, immunity, and nutritional status, remains understudied in relation to NAFLD.
Methods: A crosssectional analysis was conducted using data from 7,271 U.
Sci Rep
August 2025
Liver Center, Saga University Hospital, Nabeshima 5-1-1, Saga City, 8498501, Saga, Japan.
Liver steatosis can be measured with ultrasound techniques such as the controlled attenuation parameter (CAP) on an equipped FibroScan. For more widespread screening and quantitative evaluation of liver steatosis, a predictive model using body composition data obtained by body bioelectrical impedance analysis (BIA) was developed. In the training cohort including 365 patients suspected of having metabolic dysfunction-associated steatotic liver disease, a stepwise selection method was used to determine the BIA-related variables associated with CAP.
View Article and Find Full Text PDFBMC Public Health
August 2025
Chronic Diseases Initiative for Africa, University of Cape Town, Cape Town, South Africa.
Background: South Africa faces a high burden of malnutrition, including undernutrition, overweight, obesity, and diet-related non-communicable diseases. This coexistence and interaction of multiple forms of malnutrition within individuals and communities across the life-course is referred to as the double burden of malnutrition (DBM) and has complex, interrelated causes that need to be concurrently addressed. This qualitative study explored the drivers and potential leverage points of the DBM at individual, household, community, and (local) policy level in the Cape Town Metropolitan region.
View Article and Find Full Text PDFOpt Lett
September 2025
The optical spectrum analyzer based on stimulated Brillouin scattering (SBS-OSA) has important application potential in the field of optical communication and optical sensing due to its sub-picometer resolution. However, the sensitivity is limited by amplified Brillouin scattering (ABS) noise and Rayleigh backscattering (RB) noise. Therefore, the source and characteristics of noise in SBS-OSA are analyzed, and a noise suppression method based on polarization filtering is proposed in this paper.
View Article and Find Full Text PDFCureus
July 2025
Gastroenterology and Hepatology, Dr. Ziauddin Hospital, Karachi, PAK.
Objective Metabolic dysfunction-associated steatotic liver disease (MASLD) can rapidly progress to steatohepatitis, liver fibrosis, and hepatocellular carcinoma. However, it is a multisystem disease, and most of the MASLD-related morbidity and mortality is due to its extrahepatic complications. In light of the growing impact of MASLD on extrahepatic organs, we aimed to evaluate spleen fat deposition and compare it with liver fat deposition by vibration-controlled transient elastography using its attenuation parameter.
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