The supermassive black hole Sgr A* at the center of our galaxy produces repeating near-infrared flares that are observed by ground- and space-based instruments. This activity has been simulated in the past with magnetically arrested disk models that include stable jet formations. We used a different approach, considering a standard and normal evolution (SANE) multi-loop model that lacks a stable jet structure. The main objective of this research is to identify regions that contain current sheets and high magnetic turbulence, and to subsequently generate a 2.2 μm light curve from nonthermal particles. These aims required the identification of areas that contain current sheets and high magnetic turbulence, and the averaging of the magnetization in the regions surrounding these areas. Subsequently, particle-in-cell fitting formulas were applied to determine the nonthermal particle distribution and to obtain the sought-after light curve. Additionally, we investigated the properties of the flares, in particular their evolution during flare events, and the similarity of flare characteristics between the generated and observed light curves. We employed 2D general relativistic magnetohydrodynamic simulation data from a SANE multi-loop model and introduced thermal radiation to generate a 230 GHz light curve. Physical variables were calibrated to align with the 230 GHz observations. We identified current sheets by analyzing toroidal currents, magnetization, plasma β, density, and dimensionless temperatures. We studied the evolution of current sheets during flare events and calculated higher-energy nonthermal light curves, focusing on the 2.2 μm near-infrared range. We obtain promising $2.2 μ$m light curves whose flare duration and spectral index behavior align well with observations. Our findings support the association of flares with particle acceleration and nonthermal emission in current sheet plasmoid chains and at the boundary of the disk inside the funnel above and below the central black hole.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

Abstract Risk perceptions of energy systems, and their evolution under climate change and after accidents, affects public acceptance of generation technologies. Despite this, little is understood about how such factors impact public perception at different time scales and the drivers for perception. We use state-of-the-art natural language processing to measure temporal changes in sentiment toward energy technologies using the full twitter archive for 2009–2022. We find that perception of natural gas and wind has changed little as discussion of climate change on social media increased. However, climate-linked sentiment toward coal, solar, and hydropower has become more negative, while that for nuclear has improved. We also find that all generation technologies experience a drop in supportive discourse after definable accidents, but this typically rebounds with a half-life of less than 3 days. Yet, nuclear power is an exception in how it reacts to large scale events. After Fukushima, sentiment returned to its positive pre-accident levels with an 11.3-month relaxation half-life.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

Abstract Objective To report our initial experience using a simple principle that helps mini-endoscopic relocation of the guidewire into renal pelvis, ureter or upper calyx to improve percutaneous nephrolithotomy (PNL) puncture efficacy and enable safe dilatation. Methods A hydrophilic guidewire (sensor) was introduced through the access needle to calyx with a casting stone. 8 F Alken guide rod was passed over the guidewire followed by serial dilatation until the 4th Alken dilator (18F). Mini-perc outer sheath (18 F) was passed over under fluoroscopic guidance. A 8/11 Fr semirigid ureteroscope was progressed through the mini-perc sheath. A second sensor guidewire was passed, negotiated at the side of the stone to run through the infundibulum and renal pelvis down to the ureter or up to upper calyx under direct ureteroscopic vision. Routine tract dilatation by sequential rigid Alken metal dilators was done to enlarge the tract to 30 Fr. Results Our technique was employed on 14 (23%) out of 61 cases of PNL. Mean patient age was 47.5 yrs. Average stone size was 4.3 cm. Mean mini-endoscopic time taken to relocate the guidewire into the ureter or upper calyx was 63 s. Mini-endoscopic fluoroscopy time from introduction of ureteroscope to passage of sensor guidewire into ureter or upper calyx was 7.7 s. No mini-endoscopic access complication reported. Conclusion The mini-endoscopic access directs and facilitates initial percutaneous access and dilatation safely with reducing radiation exposure. Technique novelty is due to being a simple, safe, effective, economic and benefit in simplifying the early learning curve of PNL.

• Book : 31(1)
• Pub. Date : 2025
• Page :
• Keyword :

• Book : 20(1)
• Pub. Date : 2025
• Page :
• Keyword :

Abstract Purpose The new high resolution positron emission tomography (PET) myocardial perfusion imaging tracer, 18F-flurpiridaz, is set to enter clinical use soon following its recent regulatory approval. We developed an approach for evaluating subendocardial analysis for stress total perfusion deficit (TPD) and ischemic TPD, assessed its performance for detection of coronary artery disease (CAD) and compared these measures to transmural analysis and expert physician assessments. Methods Myocardial perfusion image data from the 18F-flurpiridaz phase III clinical trial (NCT01347710) were used. The subendocardial layer was automatically defined on the left ventricular contours and used for the derivation of polar maps. Areas under the receiver operating characteristic curve (AUC) for quantitative and visual measures were evaluated for detecting CAD, defined as ≥ 50% stenosis by invasive coronary angiography. Results In total, 753 cases were analyzed, with a median age of 63 (interquartile range 56,69) and 69% male. AUC for detecting ≥ 50% stenosis was higher for subendocardial than transmural analysis for stress (0.795 vs. 0.762, respectively; p = 0.013) and ischemic (0.795 vs. 0.767, respectively; p = 0.049) TPD. Subendocardial and transmural TPD achieved diagnostic performance greater than or comparable to that of the readers’ assessments in the total population as well as across subgroups of interest. Conclusion Subendocardial analysis of ischemic perfusion improves the detection of CAD compared to transmural quantitative analysis or expert visual reading. These measures can be derived automatically with minimal user interaction. Integrating TPD quantitative measures could standardize the diagnostic approach for this novel tracer.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

Abstract While the implication of a dysfunctional dopaminergic system in Tourette syndrome (TS) is well established, the underlying pathophysiological mechanisms remain unclear. Apart from neurotransmitters, disturbed iron homeostasis and iron regulatory mechanisms are also suspected. Iron is a trace element of fundamental biological importance and is involved in the synthesis and metabolism of dopamine and its receptors and transporters. The goal of the current pre-registered, multi-modal, cross-sectional study was to investigate the relationship between potential iron homeostasis imbalances and dopaminergic system disturbances in patients with TS. Susceptibility-sensitive magnetic resonance imaging at 7T was used to obtain surrogate measures for local brain iron in 25 patients with TS (age 30±9 years, 6 female) and 40 matched control subjects. Additionally, dopamine D1 receptor availability was investigated with [11C]SCH23390 positron emission tomography in a subgroup of 20 patients and 20 controls. Significantly reduced subcortical magnetic susceptibility, indicating reduced iron levels, was observed in TS patients in the caudate, pallidum, subthalamic nucleus, thalamus, red nucleus, and substantia nigra. These reductions were accompanied by significant reductions of the [11C]SCH23390 binding potential indicating reduced availability of D1 receptors in the dorsal striatum. The D1 receptor abnormality correlated with tic severity. These results point to alterations of intrasynaptic dopamine release and reduced striatal D1 receptor binding, supporting the notion of disruption in multiple functional elements of the dopaminergic system. Such dopaminergic abnormalities appear to be associated with disturbances in iron homeostasis.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

• Book : ()
• Pub. Date : 2025
• Page : pp.104612-104612
• Keyword :

Abstract SARS-CoV-2 can encode circular RNAs (circRNAs); however, the potential effects of exogenous SARS-CoV-2 circRNAs on cardiovascular sequelae remain unknown. Three circRNAs derived from the nucleocapsid (N) gene of SARS-CoV-2, namely, circSARS-CV2-Ns, were identified for functional studies. In particular, circSARS-CV2-N1368 was shown to enhance platelet adhesiveness to endothelial cells (ECs) and inhibit EC-dependent vascular relaxation. Moreover, exogenous expression of circSARS-CV2-N1368 suppressed EC proliferation and migration and decreased angiogenesis and cardiac organoid beating. Mechanistically, we elucidated that circSARS-CV2-N1368 sponged the microRNA miR-103a-3p, which could reverse circSARS-CV2-N1368-induced EC damage. Additionally, activating transcription factor 7 (ATF7) was identified as a target gene of miR-103a-3p, and Toll-like receptor 4 (TLR4) was verified as a downstream gene of ATF7 that mediates circARS-CV2-N1368-induced activation of nuclear factor kappa B (NF-κB) signaling and ROS production in ECs. Importantly, the reactive oxygen species (ROS) scavenger NAC mitigated the circSARS-CV2-N1368-promoted EC impairment. Our findings reveal that the TLR4/NF-κB/ROS signal pathway is critical for mediating circSARS-CV2-N1368-promoted oxidative damage in ECs, providing insights into the endothelial impairment caused by circSARS-CV2-Ns.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :