Abstract

Objective. Inter- and intra-fractional anatomical changes during a radiotherapy treatment can cause differences between the initially planned dose and the delivered dose. The total delivered dose can be accumulated over all fractions by using deformable image registration (DIR). However, there is uncertainty in this process which should be accounted for. The aim of this study is to propose a novel metric estimating the spatial distribution of the accumulated dose uncertainty and to evaluate its performance for multi-fraction online adaptive treatments. Approach. We postulate a new metric, the delta (δ) index, to estimate the uncertainties associated with the dose accumulation process. This metric is calculated for each voxel and takes into account the spatial uncertainty in DIR and local dose differences. For the spatial uncertainty of the DIR, the distance discordance metric was used. The accumulated dose and the δ index were determined for ten lung stereotactic body radiation therapy patients. The δ index was complemented by a more understandable metric, the δ index passing rate, which is the percentage of points satisfying the passing criteria in a region. Main results. The spatial distribution of the δ index and the δ index passing rates showed that voxels failing the criteria were predominantly in lower-dose regions. The mean percentage of voxels passing the criterion increased from 65% to 78%, for threshold doses of 20% and 90% of the prescription doses, respectively. Significance. The δ index was postulated to quantify the spatial distribution of the uncertainties associated with the dose accumulation process. The metric gives an intuitive understanding of the reliability of accumulated dose distributions and derived DVH metrics. The performance of the δ index was evaluated for multi-fraction online adaptive treatments, where a case of sub-optimal image registration was identified by the metric.

• Book : 70(1)
• Pub. Date : 2025
• Page : pp.015003
• Keyword :

• Book : 238()
• Pub. Date : 2025
• Page : pp.126509
• Keyword :

Abstract

We have proposed a magneto-optical photonic crystal (MOPC) waveguide that can not only realize highly directional radiation but also work as an electromagnetic (EM) wave receiver. This waveguide consists of a square MOPC and a covering layer of Al2O3 PC tilted at 45° that allows for the penetration of EM waves. Due to the broken time-reversal symmetry caused by an external magnetic field, there exists a unidirectional leaky topological edge state within the photonic bandgap. Such the leaky edge state transmits unidirectional and radiates into the air simultaneously, leading to a broadside radiation beam with a low half-power beam width of less than 4°. More importantly, the radiation direction of the beam can be tuned over a wide angular range by adjusting the operation frequency or the magnetic field strength. Besides, this designed waveguide can also act as a tunable receiver for capturing incident EM waves effectively. These results have potential for various practical applications, such as antennas and sensors.

• Book : 58(8)
• Pub. Date : 2025
• Page : pp.085103
• Keyword :

• Book : 1010()
• Pub. Date : 2025
• Page : pp.116781
• Keyword :

Abstract

Charged lepton flavor violation (CLFV) represents a clear new physics (NP) signal beyond the standard model (SM). In this work, we investigate the CLFV decays of vector mesons $ V \rightarrow l _{ i }^{ \pm } l _{ j }^{ \mp } $ with V ∈ {ϕ, J/Ψ, ϒ(1S), ϒ(2S), ϒ(3S)} in the U(1)XSSM. Considering the SM-like Higgs boson mass within 3σ region and the experimental upper bounds of Br(lj → liγ), we discuss the corresponding constraints on the relevant parameter space of the model. From the numerical analyses, the CLFV sources originated from the non-diagonal elements correspond to the initial and final generations of the leptons. And the branching ratios to these CLFV processes can easily reach the present experimental upper bounds, which indicate that this model can produce significant contributions to such CLFV decays. Therefore, searching for CLFV processes of vector mesons may be an effective channel to study NP.

• Book : 52(1)
• Pub. Date : 2025
• Page : pp.015008
• Keyword :

• Book : 605()
• Pub. Date : 2025
• Page : pp.155589
• Keyword :

• Book : 605()
• Pub. Date : 2025
• Page : pp.155577
• Keyword :

Abstract

This article presents a defected ground structure (DGS)-based deformed microstrip wearable antenna for ON/OFF body smart wearable Internet of Things (IoT) applications.. The antenna design has certain features such as lightweight, cost-effectiveness, low profile, and flexibility. Fabricated using a Rogers RT/Duroid 5880 substrate with a thickness of 0.508 mm, the proposed antenna includes a deformed rectangular patch and DGS to enhance impedance matching and radiation performance at 2.45 GHz. The results show a low reflection coefficient of approximately −36 dB and a peak gain of 5.61 dBi at 2.45 GHz in a free-space environment without bending. Additionally, the specific absorption rate (SAR) is measured to be 0.249 W kg⁻¹ for 1 g of tissue and 0.137 W kg⁻¹ for 10 g of tissue when the antenna is placed 0.32λ0 away from the body. The study also indicates that SAR values decrease as the distance between the antenna and the body increases. The antenna prototype has been fabricated and experimentally tested under various ON/OFF body conditions and bending scenarios. The measured results closely align with the simulated data, confirming the antenna suitability for ON/OFF body IoT applications. Noteworthy features of the proposed wearable antenna include its conformability and suitability for body-worn applications, making it an excellent candidate for ON/OFF body smart wearable IoT devices.

• Book : 100(1)
• Pub. Date : 2025
• Page : pp.015536
• Keyword :

Abstract

Neurotoxic A1 reactive astrocytes are induced by inflammatory stimuli. Leptin has been confirmed to have neuroprotective properties. However, its effect on the activation of A1 astrocytes in infectious inflammation is unclear. In the current study, astrocytes cultured from postnatal day 1 Sprague-Dawley rats were stimulated with lipopolysaccharide (LPS) to induce an acute in vitro inflammatory response. Leptin was applied 6 h later to observe its protective effects. The viability of the astrocytes was assessed. A1 astrocyte activation was determined by analyzing the gene expression of C3, H2‐D1, H2‐T23, and Serping 1 and secretion of pro‐inflammatory cytokines IL‐6 and TNF‐α. The levels of phospho‐p38 (pp38) and nuclear factor‐κB (NF‐κB) phosphor‐p65 (pp65) were measured to explore the possible signaling pathways. Additionally, an LPS‐induced inflammatory animal model was established to investigate the in vivo effects of leptin on A1 astrocytic activation. Results showed that in the in vitro culture system, LPS stimulation caused elevated expression of A1 astrocyte‐specific genes and the secretion of pro‐inflammatory cytokines, indicating the activation of A1 astrocytes. Leptin treatment significantly reversed the LPS induced upregulation in a dose‐dependent manner. Similarly, LPS upregulated pp38, NF‐κB pp65 protein and inflammatory cytokines were successfully reduced by leptin. In the LPS‐induced animal model, the amelioratory effect of leptin on A1 astrocyte activation and inflammation was further confirmed, showed by the reduced sickness behaviors, A1 astrocyte genesis and inflammatory cytokines in vivo. Our results demonstrate that leptin efficiently inhibits LPS‐induced neurotoxic activation of A1 astrocytes and neuroinflammation by suppressing p38‐MAPK signaling pathway.

• Book : 73(1)
• Pub. Date : 2025
• Page : pp.25-37
• Keyword :

• Book : 1055()
• Pub. Date : 2025
• Page : pp.123009
• Keyword :