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The rapid growth in wireless telecommunication systems has spurred a strong interest in lightweight, compact, and cost-effective materials. One promising solution for achieving these characteristics is using polymer matrix ceramic-reinforced composites. In this context, complex oxide materials, specifically Zn1-xCuxWO4 (where x=0 and x=0.03), were used to reinforce three different polymer matrices: epoxy, polyurethane, and silicone rubber. The primary objective was to create composites with low loss factors and high dielectric constants, essential qualities for telecommunications systems. To create the complex oxides, the solid-state reaction method was employed. In particular, the X-ray diffraction (XRD) analysis confirmed that Zn0.97Cu0.03WO4 exhibited a monoclinic phase structure similar to that of ZnWO4. Moreover, the impact of substituting copper ions on the dielectric properties was thoroughly examined through Rietveld refinement of X-ray diffraction data. Subsequently, composite materials were prepared using a simple hand-mixing method with 5% and 10% volume fractions of Zn1-xCuxWO4 (x=0 and x=0.03) integrated into the three different polymer matrices. To this end, the study extensively analyzed how the filler content and its concentration influenced the dielectric properties of these composites. The dielectric properties were characterized within the C-band frequency range, specifically from 4 to 8 GHz, utilizing transmission/reflection measurements with a vector network analyzer (VNA). The results confirm the potential enhancement of Zn0.97Cu0.03WO4/polymer composites compared to ZnWO4/polymer composites. More precisely, 10% Vf. Zn0.97Cu0.03WO4/epoxy composite and 10% Vf Zn0.97Cu0.03WO4/polyurethane composite showed satisfactory properties with (ϵr= 1.36 x 102, tanδ= 4.72 x 10-1 at 7.1 GHz) and (ϵr= 1.18 x 102, tanδ= 4.72 x 10-1 at 7.1 GHz), respectively.

Epoxy–nanoceramic composites of BiVO4 (BVO), LaNbO4 (LNO), and Li6Mg7Ti3O16 (LMT) were prepared using the solvent mixing method. The ceramic nano-fillers volume fractions were (5, 8, 10, and 12%). X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) were used to investigate the crystal structure and size distribution of nanoceramics, respectively. The dielectric constant and loss tangent were measured in the frequency range of (4-8) GHz. The measurement technique was the waveguide approach via a Vector Network analyzer (VNA). The effect of the volume fraction of ceramic fillers on the dielectric constant and loss tangent of the composites at 5.28 GHz (5G) was investigated. This work aims to design composite materials for 5G antennas of lower cost while maintaining the properties of 5G antennas. The results show that an optimum volume fraction of the ceramic filler brings the dielectric properties to their best value. However, epoxy composite with a 5% volume fraction of LMT shows good microwave dielectric properties (dielectric constant = 2.17 and loss tangent = 0.011) at 5.28 GHz. In addition, epoxy- LMT composite with an exceptionally low volume fraction of 5% provides a low-cost material for a 5G antenna. Another aspect of the cost reduction is the elimination of the costly and troublesome compaction and high-temperature sintering process. Furthermore, the epoxy composite overcomes the disadvantages of the high brittleness of the sintered all-ceramic products. As a result, epoxy composite with the 5% volume fraction of LMT is a potential candidate for 5G antenna materials.

Bioglass offers a variety of uses for tissue engineering due to its good biocompatibility and chemical composition, similar to a mineral portion of the body. The synthesis of bioglass 13-93 scaffold was achieved by salt leaching technique, and potassium chloride (KCl) was used as porogen with particle sizes of (200-250) μm. Then, sintering to 750 ◦C for around 1 hour was performed. The resultant materials were examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). They were immersed in a solution of simulated body fluids (SBF) for 7 and 14 days, respectively. Initially, calcium phosphate was created. After 7 and 14 days, the surface comprised of developed crystalline apatite. The bioactivity of scaffolds that were created and examined. The FTIR, SEM, and XRD experiments were done before and after immersion of the sample in SBF. The results showed that the scaffolds contained open and interconnected pores with porosities ranging between (75-78%). The maximum value of compressive strength of the prepared scaffold was about 5.6MPa. Based on the obtained results, the glass scaffolds can be considered promising for bone defects and replacement applications

Graphene is one of the most important forms of carbon. Due to its exceptional physical, chemical, and mechanical properties, it’s used in different fields such as electronic, energy storage, and medical applications. Therefore, the production of graphene in large quantities, at a low cost, and high quality, has become critical. Using graphite powder, a few layers of graphene sheets were prepared via a series of mechanical exfoliation methods. the dry ball milling process by the planetary mill was used. Thereafter, the milling was followed by shear force and then supported by ultra-sonication to reach the lowest level of the graphene layers. Morphological properties were examined using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Also, structural characterizations were investigated using Raman spectra and X-ray diffraction measurements (XRD) and (FTIR). Findings presented in this research highlighted that the synthesis method followed was found to have several advantages, including low cost and the ease of producing a few layers of graphene nanosheets. Subsequently, the promising efficiency of the used methodology is important.

Hydroxyapatite is one of the most bioactive materials used in tissue engineering due to its excellent biocompatibility and chemical composition which is equivalent to the mineral element of bone. In this study, polymer sponge replication method was used to fabricate porous hydroxyapatite scaffolds. Pure phase of hydroxyapatite scaffolds and the chemical bonding were verified via Fourier Transform Infrared and X-ray diffraction. Emission scanning electron microscopy (F E S E M) examination showed that the proposed scaffold has high interconnected pores that were achieved just after sintering at temperatures 1350 ºC for 2 hours. The percentage porosity values were estimated to be between 75–78 percent. The bioactivity of porous scaffolds was also investigated. They were submerged in a slurry of simulated body fluid (S B F) for seven, fourteen, and twenty-one days, respectively. Both FESEM and XRD analysis have confirmed the bioactivity of the prepared porous hydroxyapatite scaffold through the formation of a dense layer of apatite on its surface. Based on the results, the porous hydroxyapatite scaffolds could be recommended as a critical option for bone defects as well as replacement applications.

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

Objective: Obesity in adolescent males is associated with the lowering of total and free testosterone concentrations. Weight loss may increase testosterone concentrations. Design and methods: We evaluated the changes in sex hormones following bariatric s urgery in 34 males (age range: 14.6-19.8 years) with obesity. These participants were part of a prospective multicenter study, Teen-Longitudinal Assessment of Bariatric Surgery. The participants were followed up for 5 years after surgery. Total testosterone, total estradiol, luteinizing hormone, follicle-stimulating hormone, sex hormone-binding globulin, C-reactive protein, insulin and glucose were measured at baseline, 6 months and annually th ereafter. Free testosterone, free estradiol and HOMA2-IR were calculated. Results: Study participants lost one-third of their body weight after b ariatric surgery, with maximum weight loss achieved at 24 months for most participants. Free testosterone increased from 0.17 (95% CI: 0.13 to 0.20) at baseline to 0.34 (95% CI: 0.30 to 0.38) and 0.27 nmol/L (95% CI: 0.23 to 0.32) at 2 and 5 years (P < 0.001 for both), respectively. Total testosterone increased from 6.7 (95% CI: 4.7 to 8.8) at b aseline to 17.6 (95% CI: 15.3 to 19.9) and 13.8 (95% CI: 11.0 to 16.5) nmol/L at 2 and 5 years ( P < 0.001), respectively. Prior to surgery, 73% of the participant s had subnormal free testosterone (<0.23 nmol/L). After 2 and 5 years, only 20 and 33%, respectivel y, had subnormal free testosterone concentrations. Weight regain was related to a fall in free tes tosterone concentrations. Conclusions: Bariatric surgery led to a robust increase in testosterone con centrations in adolescent males with severe obesity. Participants who regained weight had a decline in thei r testosterone concentrations. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to evaluate the association of testosterone deficiency with inflammation and how long-term testosterone therapy affects inflammation biomarkers over time.Methods: We conducted a 2-component study. First, we conducted a cross-sectional study using the recently released 2015-2016 National Health and Nutrition Examination Survey (NHANES) data to examine the association between testosterone deficiency and inflammation biomarkers including high sensitivity C-reactive protein (hsCRP), liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the US general population. Then we conducted a longitudinal study to investigate the longitudinal effect of testosterone therapy on inflammation biomarkers and the risk of cardiovascular events, using data from 776 hypogonadal men based on a registry study in Germany with up to 11 years' follow-up.Results: The adjusted odds ratios (ORs) describing the associations between testosterone deficiency and hsCRP ≥ 3mg/L, ALT > 40U/L, and AST > 40U/L were 1.81 (P-value < 0.001), 1.46 (P-value = 0.009), and 0.99 (P-value = 0.971), respectively. In the control group, CRP, ALT, and AST levels increased by 0.003 (95%CI: -0.001, 0.007) mg/L, 0.157 U/L (95%CI: 0.145, 0.170), and 0.147 (95%CI: 0.136, 0.159) U/L per month, while in the treatment group, CRP, ALT, and AST levels decreased by 0.05 (95%CI: -0.055, -0.046) mg/L, 0.142 U/L (95%CI: -0.154, -0.130), and 0.148 (95%CI: -0.158, -0.137) U/L per month.Conclusion: Testosterone deficiency was associated with an increased level of inflammation; long-term testosterone therapy alleviated inflammation among hypogonadal men, which may contribute to the reduced cardiovascular risk. Future large trials are warranted to confirm our observational study findings. [ABSTRACT FROM AUTHOR]