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 :

• Book : 47(1)
• Pub. Date : 2025
• Page : pp.782-792
• Keyword :

Diffuse scattering is a component of the powder pattern bearing information on the local atomic structure and disorder of crystalline materials. It is visible in the X-ray diffraction patterns of binary structures like Ag2O, which has a large mean squared displacement for its constituent elements. Pair distribution function (PDF) analysis is widely employed to extract this local structural information, embedded in the widths of PDF peaks. However, obtaining the PDF from experimental data requires a Fourier transform, which introduces aberrations in the transformed data due to instrument resolution, complicating the distinction between its static and dynamic components. In this work, the analysis of thermal diffuse scattering is performed directly on the X-ray powder pattern, using the traditional Rietveld method integrated with a correlated displacement model for atomic pairs. The Ag2O case study data were collected using synchrotron radiation at room temperature, supplemented by laboratory experiments up to 200°C. An Einstein model was used to obtain the harmonic and anharmonic force constants of the system. The force constants were also obtained via density functional theory and ab initio molecular dynamics simulations and showed similar values to the experiments. The analysis reveals the complex dynamic structure of Ag2O, characterized by high anisotropy in phonon dispersion relations and the presence of soft phonon modes, which explain the significant displacement parameters observed. The proposed approach can be easily employed for other binary or more complex systems to understand the dynamics of local forces through X-ray diffraction analysis.

• Book : 58(1)
• Pub. Date : 2025
• Page :
• Keyword :

• Book : 11(1)
• Pub. Date : 2025
• Page : pp.e41319
• Keyword :

In this study, composite castings of electrically conductive materials were prepared using electromagnetic energy of frequency 2.45 GHz. Three separate sets of castings were produced inside the domestic microwave applicator cavity, with reinforced compositions of up to 15% in steps of 5% for each composite cast (copper (Cu) + 5% molybdenum (Mo), Cu + 10% Mo, and Cu + 15% Mo). A microwave radiation exposure time of 12 min was required for the complete melting of pure copper powder. However, the addition of Mo reinforcement caused a reduction in exposure time to 11.33 min (min) for the Cu-15% Mo composite cast. The formation of different phases was revealed by the X-ray diffraction analysis of the cast samples. Only a 0.92% copper oxide phase was detected in the pure copper cast samples. The composite cast samples exhibited peaks corresponding to Cu64O, Cu6Mo5O18, and MoO2. Microstructure analysis demonstrated that the grains grew in an equiaxed manner with a uniform dispersion of the reinforcements. The maximum microhardness achieved is 99.2 ± 4.99 Hv for Cu + 15% Mo which is 1.66 times better than microwave-cast copper sample.

• Book : 239(1)
• Pub. Date : 2025
• Page : pp.31-43
• Keyword :

• Book : 51()
• Pub. Date : 2025
• Page : pp.100906
• Keyword :

• Book : 36(1)
• Pub. Date : 2025
• Page : pp.14
• Keyword :

• Book : 18(1)
• Pub. Date : 2025
• Page : pp.101239
• Keyword :