Search Results (52)

We present a case with unusual findings on nuclear imaging after mild SARS-CoV-2 infection. During evaluation for an incidentaloma, 18F-Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography imaging showed activity in the thyroid gland, in the lower thoracic spinal column, in portal lymph nodes, and in the terminal ileum and surrounding lymph nodes, all suspicious for metastatic cancer. The patient underwent extensive invasive and non-invasive diagnostic procedures, including biopsies of all the suspicious foci, only showing a small low-grade thyroid cancer that would often be followed and not immediately operated on. Three months later, the findings had either disappeared or were considered reactive. The patient later recalled having had mild COVID-19 seven days prior to the PET/CT. Full article

Magnetic resonance imaging (MRI) is a powerful medical imaging technique used for acquiring high-resolution anatomical and functional images of the human body. With the development of an 11.74 Tesla (T) human MRI system at our facility, we are designing novel radiofrequency (RF) coils optimized for brain imaging at ultra-high fields. To meet specific absorption rate (SAR) safety limits, this study focuses on localized imaging of individual brain lobes rather than whole-brain array designs. Conventional loop coils, while widely used, offer limited |B₁|-field uniformity at 500 MHz—the Larmor frequency at 11.74 T, which can reduce image quality. Therefore, it is important to develop antennas and coils for highly uniform fields. As an alternative, we propose an elliptical microstrip design, which combines the compact resonant properties of microstrips with the enhanced field coverage provided by loop geometry. We simulated a three-element elliptical microstrip array and compared its performance with a conventional loop coil. The proposed design demonstrated improved magnetic field uniformity and coverage across targeted brain regions. Preliminary bench-top validation confirmed the feasibility of resonance tuning at 500 MHz, supporting its potential for future high-field MRI applications. Full article

Vehicles are rapidly evolving into objects of intelligent interconnection. Vehicle-to-Vehicle (V2V) communications enable the interconnection between vehicles, while also leading to new electromagnetic exposure scenarios. This paper integrates a monopole array antenna into a shark-fin antenna on the car roof for V2V communications and evaluates the specific absorption rate (SAR) and temperature rise of a human body in a smart mobility communication scenario operating at 5.9 GHz. The V2V antenna is modeled and placed on a 3D vehicle model using COMSOL Multiphysics (v.6.2) to numerically estimate the SAR in the head and body regions of the human body model (adult male) inside the vehicle. Both the localized and whole-body 30 min average SAR are lower than the International Commission on Non-Ionizing Radiation Protection (ICNIRP) occupational restrictions for electromagnetic field exposure from 100 kHz to 6 GHz, being equal in the worst-case scenario to 0.981 W/kg (for the head), which is 9.81% of the ICNIRP limit (10 W/kg), and 0.008728 W/kg (for the whole-body average), which is 2.18% of the ICNIRP limit (0.4 W/kg). The 30 min average human core temperature rise is 0.055 °C, which is 5.5% of the ICNIRP limit. This indicates that, in typical automotive scenarios, the electromagnetic exposure from a monopole array antenna for V2V communications does not pose threat to the human body. This study provides knowledge related to emerging exposure scenarios in intelligent mobility communication, which is beneficial for evaluating possible health impacts and designing public health management policies. Full article

Discovered in late 2019, the SARS-CoV-2 coronavirus has caused the largest pandemic of the 21st century, claiming more than seven million lives. In most cases, the COVID-19 disease caused by the SARS-CoV-2 virus is relatively mild and affects only the upper respiratory tract; it most often manifests itself with fever, chills, cough, and sore throat, but also has less-common mild symptoms. In most cases, patients do not require hospitalization, and fully recover. However, in some cases, infection with the SARS-CoV-2 virus leads to the development of a severe form of COVID-19, which is characterized by the development of life-threatening complications affecting not only the lungs, but also other organs and systems. In particular, various forms of thrombotic complications are common among patients with a severe form of COVID-19. The mechanisms for the development of thrombotic complications in COVID-19 remain unclear. Accumulated data indicate that the pathogenesis of severe COVID-19 is based on disruptions in the functioning of various innate immune systems. The key role in the primary response to a viral infection is assigned to two systems. These are the pattern recognition receptors, primarily members of the toll-like receptor (TLR) family, and the complement system. Both systems are the first to engage in the fight against the virus and launch a whole range of mechanisms aimed at its rapid elimination. Normally, their joint activity leads to the destruction of the pathogen and recovery. However, disruptions in the functioning of these innate immune systems in COVID-19 can cause the development of an excessive inflammatory response that is dangerous for the body. In turn, excessive inflammation entails activation of and damage to the vascular endothelium, as well as the development of the hypercoagulable state observed in patients seriously ill with COVID-19. Activation of the endothelium and hypercoagulation lead to the development of thrombosis and, as a result, damage to organs and tissues. Immune-mediated thrombotic complications are termed “immunothrombosis”. In this review, we discuss in detail the features of immunothrombosis associated with SARS-CoV-2 infection and its potential underlying mechanisms. Full article

Radiofrequency electromagnetic fields (RF-EMFs) can penetrate tissues and potentially influence endocrine and brain development. Despite increased mobile phone use among children and adolescents, the long-term effects of RF-EMF exposure on brain and endocrine development remain unclear. This study investigated the effects of long-term evolution band (LTE) EMF exposure on thyroid hormone levels, crucial for metabolism, growth, and development. Four-week-old male mice (C57BL/6) were exposed to LTE EMF (whole-body average specific absorption rate [SAR] 4 W/kg) or a positive control (lead; Pb, 300 ppm in drinking water) for 4 weeks. Subsequently, the mice underwent behavioral tests including open field, marble burying, and nest building. Blood pituitary and thyroid hormone levels, and thyroid hormone-regulating genes within the hypothalamus–pituitary–thyroid (HPT) axis were analyzed. LTE exposure increased T3 levels, while Pb exposure elevated T3 and T4 and decreased ACTH levels. The LTE EMF group showed no gene expression alterations in the thyroid and pituitary glands, but hypothalamic Dio2 and Dio3 expressions were significantly reduced compared to that in the sham-exposed group. Pb exposure altered the hypothalamic mRNA levels of Oatp1c1 and Trh, pituitary mRNA of Trhr, and Tpo and Tg expression in the thyroid. In conclusion, LTE EMF exposure altered hypothalamic Dio2 and Dio3 expression, potentially impacting the HPT axis function. Further research is needed to explore RF-EMF’s impacts on the endocrine system. Full article

People have been exposed to the 900 MHz mobile phone electromagnetic field for approximately 30 years. There is still no conclusion from immature rodent experiments regarding the potential effects of nonthermal radiofrequency (RF) 900 MHz continuous wave exposure during biological development. Here, we test the hypothesis that mother rats exposed at a whole-body specific absorption rate (wbSAR) occupational (Oc) limit of the International Commission on Non-Ionizing Radiation Protection for humans (0.4 W/kg) will show impairments in development, with less effect at the public (Pu) limit (0.08 W/kg). The wbSAR was estimated at 0.4 W/kg to mimic working mothers (OcM exposure) and 0.08 W/kg for non-working mothers, i.e., public (PuM exposure). This pre- and postnatal study is the first to compare public and occupational exposure limits on rat pup physical development. Litter endpoints and the descendants’ body weights and lengths were recorded regularly from birth concomitantly with the age of developmental landmarks. Male neonates showed earlier pinna ear detachment and earlier eye opening in both the OcM and PuM groups, but earlier incisor eruption only in the PuM group. The OcM-exposed males showed lower body weight as juveniles until adolescence. The OcM- and PuM-exposed descendant females showed earlier pinna ear detachment and eye opening with similar body weight. These data suggest variations in the development time of descendant rats when the mother rats received daily 900 MHz continuous waves at human limits for workers and non-workers (public). Full article

Pulmonary function examinations are critical to assess respiratory disease severity in patients. In preclinical rodent models of viral respiratory infections, however, disease is frequently evaluated based on virological, pathological and/or surrogate clinical parameters, which are not directly associated with lung function. To bridge the gap between preclinical and clinical readouts, we aimed to apply unrestrained whole-body plethysmography (WBP) measurements in a SARS-CoV-2 Syrian hamster challenge model. While WBP measurements are frequently used for preclinical research in mice and rats, results from studies in hamsters are still limited. During unrestrained WBP measurements, we obtained highly variable breathing frequency values outside of the normal physiological range for hamsters. Importantly, we observed that animal movements were recorded as breaths during WBP measurements. By limiting animal movement through either mechanical or chemical restraint, we improved the reliability of the lung function readout and obtained breathing frequencies that correlated with clinical signs when comparing two different variants of SARS-CoV-2 post-inoculation. Simultaneously, however, new sources of experimental variation were introduced by the method of restraint, which demands further optimalization of WBP measurements in Syrian hamsters. We concluded that WBP measurements are a valuable refinement either in combination with video recordings or if average values of measurements lasting several hours are analyzed. Full article

Consistent with the biochemistry of coronaviruses as well established over decades, SARS-CoV-2 makes its initial attachment to host cells through the binding of its spike protein (SP) to sialylated glycans (containing the monosaccharide sialic acid) on the cell surface. The virus can then slide over and enter via ACE2. SARS-CoV-2 SP attaches particularly tightly to the trillions of red blood cells (RBCs), platelets and endothelial cells in the human body, each cell very densely coated with sialic acid surface molecules but having no ACE2 or minimal ACE2. These interlaced attachments trigger the blood cell aggregation, microvascular occlusion and vascular damage that underlie the hypoxia, blood clotting and related morbidities of severe COVID-19. Notably, the two human betacoronaviruses that express a sialic acid-cleaving enzyme are benign, while the other three—SARS, SARS-CoV-2 and MERS—are virulent. RBC aggregation experimentally induced in several animal species using an injected polysaccharide caused most of the same morbidities of severe COVID-19. This glycan biochemistry is key to disentangling controversies that have arisen over the efficacy of certain generic COVID-19 treatment agents and the safety of SP-based COVID-19 vaccines. More broadly, disregard for the active physiological role of RBCs yields unreliable or erroneous reporting of pharmacokinetic parameters as routinely obtained for most drugs and other bioactive agents using detection in plasma, with whole-blood levels being up to 30-fold higher. Appreciation of the active role of RBCs can elucidate the microvascular underpinnings of other health conditions, including cardiovascular disease, and therapeutic opportunities to address them. Full article

Compared to Chinese indigenous sheep, Western sheep have rapid growth rate, larger physique, and higher meat yield. These excellent Western sheep were introduced into China for crossbreeding to expedite the enhancement of production performance and mutton quality in local breeds. Here, we investigated population genetic structure and genome-wide selection signatures among the Chinese indigenous sheep and the introduced sheep based on whole-genome resequencing data. The PCA, N-J tree and ADMIXTURE results showed significant genetic difference between Chinese indigenous sheep and introduced sheep. The nucleotide diversity (π) and linkage disequilibrium (LD) decay results indicated that the genomic diversity of introduced breeds were lower. Then, F_st & π ratio, XP-EHH, and de-correlated composite of multiple signals (DCMS) methods were used to detect the selection signals. The results showed that we identified important candidate genes related to growth rate and body size in the introduced breeds. Selected genes with stronger selection signatures are associated with growth rate (CRADD), embryonic development (BVES, LIN28B, and WNT11), body size (HMGA2, MSRB3, and PTCH1), muscle development and fat metabolism (MSTN, PDE3A, LGALS12, GGPS1, and SAR1B), wool color (ASIP), and hair development (KRT71, KRT74, and IRF2BP2). Thus, these genes have the potential to serve as candidate genes for enhancing the growth traits of Chinese indigenous sheep. We also identified tail-length trait-related candidate genes (HOXB13, LIN28A, PAX3, and VEGFA) in Chinese long-tailed breeds. Among these genes, HOXB13 is the main candidate gene for sheep tail length phenotype. LIN28A, PAX3, and VEGFA are related to embryonic development and angiogenesis, so these genes may be candidate genes for sheep tail type traits. This study will serve as a foundation for further genetic improvement of Chinese indigenous sheep and as a reference for studies related to growth and development of sheep. Full article

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes enhanced mortality in people with metabolic and cardiovascular diseases. Other highly infectious RNA viruses have demonstrated dependence on glucose transport and utilization, so we hypothesized that SARS-CoV-2 infection could lead to alterations in cellular and whole-body glucose metabolism. Twenty-four healthy domestic cats were intratracheally inoculated with B.1.617.2 (delta) SARS-CoV-2 and samples were collected at 4- and 12-days post-inoculation (dpi). Blood glucose and circulating cortisol concentrations were elevated at 4 and 12 dpi. Serum insulin concentration was statistically significantly decreased, while angiotensin 2 concentration was elevated at 12 dpi. SARS-CoV-2 RNA was detected in the pancreas and skeletal muscle at low levels; however, no change in the number of insulin-producing cells or proinflammatory cytokines was observed in the pancreas of infected cats through 12 dpi. SARS-CoV-2 infection statistically significantly increased GLUT protein expression in both the heart and lungs, correlating with increased AMPK expression. In brief, SARS-CoV-2 increased blood glucose concentration and cardio-pulmonary GLUT expression through an AMPK-dependent mechanism, without affecting the pancreas, suggesting that SARS-CoV-2 induces the reprogramming of host glucose metabolism. A better understanding of host cell metabolism and virus crosstalk could lead to the discovery of novel metabolic therapeutic targets for patients affected by COVID-19. Full article

To study physiological reactions in the brain and skin of higher mammals exposed to chronic radiofrequency radiation, specific absorption ratio (SAR) determination is required and time-consuming numerical methods are used. The paper deals with the estimation of the whole-body specific absorption rate (SAR) in rats chronically exposed to external electromagnetic fields, as well as the development of a laboratory setup simulating the operation of a fifth-generation 5G New Radio base station (with a signal bandwidth of 15 MHz and a carrier frequency of 2.4 GHz). The paper presents a modified method for theoretical SAR estimation for one-sided irradiation and distributed absorption. Mean whole-body SAR values were estimated by the proposed method and numerically modeled with the CST Microwave Studio simulation software 2020package using primitive rat models. Dielectric parameters in the numerical simulation were used from the software library. The IEEE/IEC 62704-1 algorithm was used to investigate SAR in numerical simulations. The theoretical estimates and numerical simulations were compared for different SAR distributions and were found to be qualitatively comparable. The differences between approximate theoretical estimates and numerical simulations are 7% and 10% for distributed and non-distributed absorptions, respectively. The proposed method, which takes into account the decreasing power flux density, can be used to estimate the approximate whole-body SAR during chronic electromagnetic field exposure in rats. Full article

This paper assessed the variability of radiofrequency exposure among road users in urban settings due to vehicle-to-vehicle (V2V) communication operating at 5.9 GHz. The study evaluated the absorbed dose of radiofrequencies using whole-body specific absorption rate (SAR) in human models spanning different age groups, from children to adults. To overcome limitations of previous studies, we developed a novel hybrid procedure that combines deterministic and stochastic approaches, enabling assessment across multiple urban layouts. Real urban conditions and varying propagation scenarios were considered in SAR calculations. By varying the road user’s position within 1.5–300 m from transmitting cars, the SAR distribution was determined. Median SAR remained consistently low, around 0.70 mW/kg, even with multiple transmitting cars and multiple emitting antennas, using maximum power allowed in US (44.8 dBm). The 99th percentile of SAR distribution varied based on body mass, decreasing for heavier models (typically adults) and increasing with the number of transmitting cars and antennas. The highest absorbed dose (73 mW/kg) occurred in a child model. The SAR consistently remained below the 80 mW/kg limit for whole-body exposure to electromagnetic fields in the 100 kHz–300 GHz range. Full article

Synthetic Aperture Radar (SAR) is an active microwave sensor with all-day/night and all-weather detection capability, which is crucial for detecting surface water resources. Surface water-body such as rivers, lakes, reservoirs, and ponds usually appear as dark areas in SAR images. Accurate and automated extraction of these water bodies can provide valuable data for the management and strategic planning of surface water resources and effectively help prevent and control drought and flood disasters. However, most deep learning-based methods rely on manually labeled samples for model training and testing, which is inefficient and may introduce errors. To address this problem, this paper proposes a novel water-body detection method that combines optimization algorithms and deep learning techniques to automate water-body label extraction and improve the accuracy of water-body detection. First, this paper uses a swarm intelligence optimization algorithm, Dung Beetle Optimizer (DBO), to optimize the initial cluster center of the K-means clustering algorithm, which is called the DBO-K-means (DK) method. The DK method divides the training images into four categories and extracts the water bodies in them to generate the water-body labels required for deep learning model training and testing, and the whole process does not require human intervention. Then, the labels generated by DK and training data set images are fed into the Classifier–Optimizer (CO) for training. The classifier performs a dense classification task at the pixel level, resulting in an initial result image with blurred boundaries of the water body. Then, the optimizer takes this preliminary result image and the original SAR image as input, performs fine-grained optimization on the preliminary result, and finally generates a result image with a clear water-body boundary. Finally, we evaluated the accuracy of water-body detection using multiple performance indicators including ACC, precision, F1-Score, recall, and Kappa coefficient. The results show that the values of all indicators exceed 93%, which demonstrates the high accuracy and reliability of our proposed water-body detection method. Overall, this paper presents a novel DK-based approach that improves the automation and accuracy of deep learning methods for detecting water bodies in SAR images by enabling automatic sample extraction and optimization of deep learning models. Full article

This study investigates the radio-frequency electromagnetic field exposure (RF-EMF) levels in pedestrians generated by vehicular communication technology. We specifically investigated exposure levels in children of different ages and both genders. This study also compares the children’s exposure levels generated by such technology with those of an adult investigated in our previous study. The exposure scenario consisted of a 3D-CAD model of a vehicle equipped with two vehicular antennas operating at 5.9 GHz, each fed with 1 W power. Four child models were analyzed near the front and back of the car. The RF-EMF exposure levels were expressed as the Specific Absorption Rate (SAR) calculated over the whole body and 10 g mass (SAR_10g) of the skin and 1 g mass (SAR_1g) of the eyes. The maximum SAR_10g value of 9 mW/kg was found in the skin of the head of the tallest child. The maximum whole-body SAR was 0.18 mW/kg and was found in the tallest child. As a general result, it was found that children’s exposure levels are lower than those of adults. All the SAR values are well below the limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) in the general population. Full article

As an indispensable material for animals, plants and human beings, obtaining accurate water body information rapidly is of great significance to maintain the balance of ecosystems and ensure normal production and the life of human beings. Due to its independence of the time of day and the weather conditions, synthetic aperture radar (SAR) data have been increasingly applied in the extraction of water bodies. However, there is a great deal of speckle noise in SAR images, which seriously affect the extraction accuracy of water. At present, most of the processing methods are filtering methods, which will cause the loss of detailed information. Based on the characteristic of side-looking SAR, this paper proposed a self-adaptive thresholding approach for automatic water extraction based on an OTSU algorithm and distance block. In this method, the whole images were firstly divided into uniform image blocks through a distance layer which was produced by the distance to the orbit. Then, a self-adaptive processing was conducted for merging blocks. The OTSU algorithm was used to obtain a threshold for classification and the Jeffries–Matusita (JM) distance was calculated with the classification result. The merge processing continued until the separability of image blocks reached the maximum. Subsequently, we started from the next block to repeat the merger, and so on until all blocks were processed. Ten study areas around the world and the local Dongting Lake area were applied to test the feasibility of the proposed method. In comparison with five other global threshold segmentation algorithms such as the traditional OTSU, MOMENTS, MEAN, ISODATA and MINERROR, the proposed method obtains the highest overall accuracy (OA) and kappa coefficient (KC), while this approach also demonstrates greater robustness in the analysis of time series. The findings of this study offer an effective method to improve water detection accuracy as well as reducing the influence of speckle noise and retaining details in the image. Full article