Aim: to investigate different parameters for ion chambers for the proper evaluation of absorbed radiation doses

Introduction: Many standards, codes of practice and protocols were issued internationally in order to standardize the methodologies and formalism of the use of ionization chambers in purposes of the evaluation of absorbed radiation doses in high-energy photons and electrons beams from medical linear accelerator. Methods: Three ion chambers were selected for this study: Semiflex, Farmer type (PTW), and Pinpoint ion chambers. Many correction factors and parameters controlling the behavior of ionization chambers were included in the study such as ion recombination, polarity, and response to high energy photons for each ion chambers. Results and discussion: The collection efficiencies of each ion chamber was calculated and evaluated numerically and compared to experimental data. Additionally, the beam quality correction factors were studied for each chamber, including several beam quality indices experimentally and numerically for two high energy photons: 6 MV, and 10 MV high energy photons. Two experimentally determined beam quality indices were studied for each ion chamber with respect to the reference beam quality (assumed to be the Cobalt-60 photons energy): tissue-phantom ratio TPR, and percentage depth dose PDD. All studied parameters were applied for the evaluation of the absorbed dose to water according to IAEA TRS-398 and obtained values were compared to reference values. Uncertainties associated to the evaluated values of absorbed radiation doses were discussed and presented. Conclusion: All the studied parameters are of much importance and should be considered for purposes of Radiation Metrology.

Dust in the air poses significant risks to human health. Non-respiratory particles larger than 10 micrometers can cause skin irritation and eye inflammation. Dust storms also have negative impacts on agriculture, reducing crop yields by burying seedlings, damaging plant tissue, reducing photosynthetic activity, and increasing soil erosion. Dust storms are a common phenomenon in Egypt, extending hundreds of kilometers, during spring and winter. They significantly impact transportation, sometimes leading to deaths and property damage due to the accompanying strong winds and reduced visibility. Therefore, there is a need to develop an indicator that represents the frequency and intensity of dust events based on different climate change scenarios (RCP4.5 and RCP8.5). Through this study, a dusty days index was calculated based on the maximum daily dust concentration simulated by the ICTP Regional Climate Model (RegCM4) over Egypt and the Middle East and North Africa (MENA) region. Dust intensity is classified by percentage as follows: normal (75th percentile), high (90th percentile), very high (95th percentile), and extreme (99th percentile). Climate Data Operator "CDO" was used to process the model output netCDF files and perform these calculations. The results of this study show a positive trend in air temperature over Egypt, accompanied by a negative trend in precipitation with the RCP4.5 scenario, which increased with the RCP8.5 scenario, potentially leading to increased dust emissions.

Water is an essential resource for the survival of all living things and plays a critical role in human health, the continuity of ecosystems, and economic activities. However, anthropogenic activities arising from developing industries and a growing population are negatively impacting this indispensable resource. Dyestuffs released as a result of developing industries are carried into soil, air, and water resources, causing environmental pollution. Among these dyes, reactive red 141 (RR141), due to its high solubility, reactivity, and toxicity, poses a significant environmental threat and serious risks to human health and ecosystems. Therefore, it must be treated with appropriate methods. Biosorption is the preferred method for treatment. Eggshells, considered worthless and discarded as waste, were used as biosorbents. In recent years, waste considered garbage in water pollution studies has been incorporated into the biosorption process. Accordingly, in this study, the removal potential of membrane-separated blue eggshell powder (BESP) in its native form without any modification was investigated as an environmentally friendly, economical, and effective biosorbent material. A batch biosorption process was used in the study. The effects of BESP amount (0.1-1 g), contact time (5-90 min), pH (2-10), and temperature (20-35 0C) on the removal efficiency were evaluated. Under optimum operating conditions (pH: 4; time: 30 min.; BESP dose: 0.5 g; temperature: 20 0C), the maximum RR141 removal efficiency was found to be around 81%.

Gold film-based zero-reflection metasurfaces show significant potential for advanced optical applications, including topologically controlled laser-like thermal emission. However, most proof-of-concept studies overlook the mechanical stability provided by adhesion layers, frequently refraining from their use since they disrupt the zero-reflection condition and degrade optical performance.

In this work, we aim to offer aluminium (Al) as a superior adhesion material for thin gold films that preserves both reflection intensity and resonance quality with high mechanical stability. We conclude that Al adhesion layer does not deteriorate the optical performance and provides near-electric field responses comparable to devices without adhesion layers. The advanced optical properties brought by Al are further demonstrated through the ultrasensitive detection of protein monolayers with higher sensitivities compared to other adhesive metals. We show that the metasurfaces maintain structural integrity under harsh water flow (50 ul/min) and sonication (40 kHz, 180 W) without delamination. More importantly, we conclude that the percolation threshold and native oxide formation play significant role for conserving the optical quality of devices. Our perspective is to offer a trusted pathway for transferring the exceptional optical properties of gold metal thin films to daily life usage. We present one of the best available solutions that simultaneously brings high robustness and high optical quality.

Oil-contaminated water is now a serious environmental issue caused by a variety of industries and manufacturing processes. Because of its toxicity, it endangers both the environment and other living things. Most methods for treating oily water and removing oil from water are time-consuming, expensive, need a large number of staff and equipment, and, in most cases, cause environmental damage. Adsorbents have gained popularity among available approaches in recent years due to their ease of use and low cost. The present research focuses on the possibilities of using fish scales as low-cost adsorbents for oil adsorption in water via batch processing. Fish scales were cleaned with water, dried in sunlight, and then heated in an oven at 70 °C for 1 hour before being carefully ground. The samples were passed through a 60-200-mesh sieve (74-250 mm). The materials were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM). Response surface methodology (RSM) was employed to investigate the effect of different experimental conditions on oil adsorption. To achieve the highest engine oil adsorption capacity of 90.04 mL, the following parameters were optimized: adsorption time of 33.17 minutes, agitation speed of 203.19 rpm, and adsorbent weight of 19.74 g. As a result, fish scales are a promising and environmentally benign biosorption material for the removal of contaminants from natural and wastewater sources.

Loss of dexterity in the human hand due to amputation or injury remains a significant challenge, as conventional prosthetic solutions often lack the natural motion, comfort and anatomical realism required for everyday use. Current electrically actuated prostheses rely heavily on bulky motors and complex tendon routing, which limit miniaturization and lifelike function. This research focuses on CAD modeling, simulation, and iterative 4D-printing of a bioinspired human hand that integrates shape memory alloy (SMA) wires directly into muscle-like soft tissue layers beneath a flexible skin structure. A ball-and-socket joint with three degrees of freedom is employed at the thumb’s carpometacarpal (CMC) base to replicate natural opposition and rotation, while universal joints at the metacarpophalangeal (MCP) locations provide two degrees of freedom for flexion and abduction of each finger. Hinge joints are used at the distal and proximal interphalangeal (DIP and PIP) levels to allow single axis bending. The current CAD modeling efforts focus on joint design and motion analysis using SOLIDWORKS with simulations conducted in ANSYS to validate joint kinematics and the feasibility of SMA-based electrical actuation. The work also explores multi-material 4D-printing strategies using both FDM and SLA processes. This project aims to establish a modular, anatomically accurate, and electrically driven hand prototype to demonstrate how bioinspired smart structures can make next-generation prosthetic hands more accessible, functional and lifelike.

The enthesis is the anatomical interface between the soft and hard tissues where tendons or ligaments connect into bone, the stress distribution under shear and tension loads in these areas is defined by complex transitions in collagen fiber architecture, mineral content, and stiffness. There are numerous experimental studies that detail mineral phase gradients and mesoscale mineralized spherules, however, there is limited study into their integration into scaffold design. Aiming to address this gap, this study focuses on the development of accurate models of scaffolds that replicate key functional characteristics of native enthesis function by incorporating multiscale structural features. This study makes use of the CAD software to generate scaffold geometries in order to incorporate site-specific features such as collagen fiber bundle orientation and spatial mineralization patterns. Using Finite Element Analysis (FEA) these models are then subjected to simulate physiological loading scenarios and assess mechanical behavior across the scaffold, including stiffness gradients, stress distribution, and potential failure zones. This research aims to establish a robust design framework and foundation for developing enthesis-mimicking scaffolds by integrating structural hierarch into the scaffold model and validating its mechanical performance. The goal is the development of biomaterials that support seamless tissue integration, aiding improved mechanical resilience and clinical outcomes in tissue engineering and regenerative medicine.

Existing research has not extensively explored the utilisation of machine-learning techniques to predict malaria risk. This study developed a machine-learning model to predict malaria risk based on demographic, environmental and GPS data from the Nigerian Demographic and Health Survey Program (DHS) 2000−2020. The dataset was split into a train (406 covariates) and a test (102 covariates) set. Machine learning algorithms, including Random Forest (RFR), Gradient Boosting (GB), and Logistic Regression (LR), were deployed to accurately predict malaria risk from the dataset. The results indicate that RFR has the lowest MSE (0.0003) and the highest R² (0.9816), making it the model with the best predictive accuracy and optimal for malaria prediction (MalPred) based on the DHS datasets. The regression equation is MalPred = 0.26 − 0.00NC + 0.0053PD − 0.0033TT + 0.00ITN − 0.0070RF + 0.0062MT + 0.10MI − 0.0269TJ − 0.04PET − 0.0115DLS (NC—nightlights composite; PD—population density; TT—travel time; ITNs—insecticide-treated nets; RF—rainfall; MT—minimum temperature; MI—malaria incidence; TJ—temperature in January; PET—potential evapotranspiration; DLS—dry lowland soil). The model showed that MI, MT and PD contributed the most, while TJ and PET contributed the least to malaria risk prediction in Nigeria. This study could be applied to enhancing early predictions of malaria risk using machine learning while also facilitating targeted prevention and allocation of resources in high-risk areas.

ZnO is a relevant semiconductor that continues to expand its applications. The development of new devices requires overcoming the limitations of rigid substrates. Various techniques have been used to deposit materials on flexible substrates; however, their costs are high. Therefore, the spray pyrolysis technique is promising due to its homogeneity over large surfaces, low cost, and simplicity.

For the first time, fluorine-doped ZnO films at an atomic ratio [F/Zn] of 15 at.% were deposited on polyimide substrates in a temperature range of 320-400 °C under air or N2 carrier gas using the spray pyrolysis technique. Structural, morphological, and electrical properties were investigated using X-ray diffraction, scanning electron microscopy, four-point technique, and profilometry. All films were polycrystalline with a hexagonal wurtzite structure. Films deposited at 320 and 350 °C with air gas exhibited a preferential (100) orientation, while those deposited at 350 and 400 °C with N₂ gas showed a preferential (002) orientation. The size of the crystallites increased with the temperature and N₂ gas. The morphology changed between columnar and wedge-shaped, depending on the temperature and the type of carrier gas. The resistivity decreased from 1.117x10² to 9.45x10^-2 Ω-cm with increasing temperature. At a temperature of 350 °C, the resistivity decreased by two orders of magnitude when using N₂ gas compared to the deposition with air.

The improved incorporation of fluorine and hydrogen into ZnO, using N2 gas, probably contributed to the decrease in resistivity. Spray pyrolysis was presented as an alternative method for depositing ZnO:F films on polyimide for applications in flexible electronics.

Titanium dioxide (TiO₂)​​ has been widely recognized as a promising material for addressing fossil fuel dependence and environmental degradation due to its robust photocatalytic activity, stability, and low toxicity. However, pristine TiO₂ suffers from the rapid recombination of photogenerated charge carriers and restricted visible-light absorption​​. Given this, suppressing charge recombination while extending its photoresponse to visible light would establish pristine TiO₂ as a viable candidate for scalable photocatalysis. Efforts have emphasized depositing noble-metal cocatalysts or creating heterojunctions via advanced synthesis; however, most strategies involve complex procedures, high costs, or poor reproducibility that hinder real-world implementation.

In our recent work, we developed a controllable synthesis strategy [1] to directly integrate silver (Ag) nanoparticles with TiO₂.​​ Typically, Ag nanoparticles ranging from 5 to 20 nm in size were uniformly anchored onto both the {101} and {001} facets of TiO₂ . This composite exhibited improved performance in photocatalytic hydrogen generation and organic pollutant degradation. The enhanced photocatalytic ability is attributed to the formation of stable Ti–O–Ag interfacial bonds. These bonds create an ​​efficient electron-shuttling pathway​​, accelerating the transfer of photogenerated electrons from the TiO₂ conduction band to the catalytic Ag sites, thereby facilitating charge carrier separation and enhancing light harvesting.

[1] X. Shi, M. Zhang, X. Wang, et al. Nickel nanoparticle-activated MoS2 for efficient visible light photocatalytic hydrogen evolution. Nanoscale, 2022, 14, 8601−8610.