Design optimisation of additively manufactured titanium lattice structures for biomedical implants

A key advantage of additive manufacturing (AM) is that it allows the fabrication of lattice structures for customised biomedical implants with high performance. This paper presents the use of statistical approaches in design optimisation of additively manufactured titanium lattice structures for biomedical implants. Design of experiments using response surface and analysis of variance were carried out to study the effect design parameters on the properties of the AM lattice structures such as ultimate compression strength, specific compressive strength, elastic modulus, and porosity. In addition, the lattice dimensions were optimized to fabricate a diamond cellular structure with properties that match human bones. The study found that the length of a diamond-shaped unit cell strut is the most significant design parameter. In particular, the porosity of the unit cell increases as the strut length increases, while it had a significant reverse effect on the specific compressive strength, elastic modulus and ultimate compression strength. On the other hands, increasing the orientation angle was found to reduce both the specific compressive strength and modulus of elasticity of the lattice structure. An optimised lattice structure with strut diameter of 0.84 mm, length of 3.29 mm and orientation angle of 47° was shown to have specific compressive strength, elastic modulus, ultimate compression strength and porosity of 37.8 kN.m/kg, 1 GPa, 49.5 MPa and 85.7%, respectively. A cellular structure with the obtained properties could be effectively applied for trabecular bones replacement surgeries

The validity of Wagner’s law in Egypt from 1960–2018

Purpose One of the main theories regarding the relationship between government expenditure and gross domestic product (GDP) is Wagner’s law. This law was developed in the late-19th century by Adolph Wagner (1835–1917), a prominent German economist, and depicts that an increase in government expenditure is a feature often associated with progressive states. This paper aims to examine the validity of Wagner’s law in Egypt for 1960–2018. The relationship between real government expenditure and real GDP is tested using three versions of Wagner’s law. Design/methodology/approach To test the validity of Wagner in Egypt, law time-series analysis is used. The methodology used in this paper is: unit-root tests for stationarity, Johansen cointegration approach, error-correction model and Granger causality. Findings The results provide strong evidence of long-term relationship between GDP and government expenditure. Moreover, the causal relationship is found to be bi-directional. Hence, this study provides support for Wagner’s law in the examined context. Research limitations/implications It should be noted, however, that there are some limitations to this study. For instance, in this paper, the government’s size was measured through government consumption expenditure rather than government expenditure due to data availability, which does not fully capture the government size. Moreover, the data available was limited and does not fully cover the earliest stages of industrialization and urbanization for Egypt. Furthermore, although time-series analysis provides a more contextualized results and conclusions, the obtained conclusions suffer from their limited generalizability. Originality/value This paper aims to specifically make a contribution to the empirical literature for Wagner’s law, by testing the Egyptian data using time-series econometric techniques for the longest time period examined so far, which is 1960–2018

Ion Flotation of Copper(II) and Lead(II) from Environmental Water Samples

The present study aims to develop a simple, rapid and economic procedure for copper(II) and lead(II) removal under the optimum conditions investigated. It is based on the complex formation between Cu2+ and Pb2+ ions and diphenylcarbazone (HDPC) followed by flotation with oleic acid (HOL) surfactant. The different parameters (namely: solution pH, HDPC, HOL, copper and lead concentrations, ionic strength, temperature and the presence of foreign ions) influencing the flotation process were examined. Nearly, 100% of Cu2+ and Pb2+ ions were removed from aqueous solutions at pHs 6 and 7, respectively at room temperature (~25 \ub0C). The procedure was successfully applied to recover almost copper(II) and lead(II) spiked to some natural water samples. Due to the rapid, simple and economic nature of the procedure, a flotation mechanism is suggested for metal removal in wastewater systems

Unlocking Tourism’s Potential: Pricing Strategies for the Post-COVID Renaissance

In response to the challenges faced by tourism managers in devising effective pricing strategies to overcome the impacts of the COVID-19 pandemic, this study aims to make a valuable contribution to the existing literature on tourism management and marketing. Specifically, we investigate the pricing strategies that tourists are most likely to prefer in the aftermath of the pandemic. To achieve this, we conducted semi-structured interviews with a sample size of experienced tourists in Egypt. Our findings reveal that tourists exhibit a strong inclination towards hedonic and bundling pricing strategies. This suggests that tourism managers should prioritize the incorporation of these strategies into their post-pandemic business plans. However, it is crucial for managers to carefully consider tourists’ behavioral responses to dynamic and pay-what-you-want pricing strategies, as these are influenced by various constraints that necessitate careful attention. Furthermore, our study highlights potential negative consequences associated with the implementation of the dual-pricing strategy following the pandemic. This strategy has the potential to compromise tourists’ intentions to utilize certain services, thereby leading to unfavorable behavioral outcomes for tourism destinations. The implications of this study are of practical significance for tourism managers seeking to design more effective pricing strategies to capitalize on the opportunities presented by the post-pandemic recovery period. By understanding tourists’ preferences and considering the potential drawbacks associated with certain pricing strategies, managers can make informed decisions that promote the sustainable and successful revival of the tourism industry. Moreover, our study employed the checkpoints method, which allowed us to identify respondents’ priorities for the pricing strategies during the crisis, further enhancing the validity and reliability of our findings. © 2023 by the authors.Deanship of Scientific Research, King Saud University; Kazan Federal University; King Faisal University, KFU: 3117, EGY-0026/20This study was conducted according to the guidelines of the Declaration of Helsinki and was approved by the Deanship of Scientific Research Ethical Committee (Grant No. 3117), King Faisal University.All authors thank the Deanship of Scientific Research, Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Saudi Arabia (Grant No. 3117), through its KFU Research Summer initiative. The researchers are supported by a full Ph.D. scholarship under the joint executive program between the Arab Republic of Egypt and Saint Petersburg State University for the second author (M.I.S), number EGY-0026/20 and Kazan Federal University for the third author (M.Y.H.), number Egy.6572/19

An Extracted Fraction of Pseudomonas Oleovorans Can Inhibit Viral Entry and RNA Replication of Hepatitis C Virus in Cell Culture

The emergence and distribution of Hepatitis C virus (HCV) infection is still considered as an unsolved problem. Due to side effects, many synthetic drugs have been avoided and replaced by new biologically derived ones. Aim of this study was to use Pseudomonas oleovorans’ extract as HCV viral replication inhibition agent in cell culture system. Several factors were studied and the optimum growth conditions were selected for maximum production of antiviral substance. Pseudomonas oleovorans’ extract was fractionated using different concentrations of chloroform: methanol on silica gel columns. Analysis of potent fraction by GC/MS showed of tetradecanoic and hexadecanoic acid methyl esters. The selected fraction was tested against HCV in vitro using two different protocols: viral attachment entry inhibition (Pre-incubation) and viral replication inhibition (Post infection). 0.1 µg / ml of the selected antiviral fraction resulted in inhibition of viral replication in Huh 7.5 cells. However, higher concentration of 100 µg / ml did not cause any viral inhibition. The selected bacterial fraction containing tetradecanoic acid and hexadecanoic acid methyl esters could be used as a promising candidate to inhibit viral HCV entry and replication of HCV

Structure, Morphology and Electrical/Magnetic Properties of Ni-Mg Nano-Ferrites from a New Perspective

Using the auto combustion flash method, Ni1−x+2 Mg+2xFe+32O4 (x = 0, 0.2, 0.6, 0.8 and 1) nano-ferrites were synthesized. All samples were thermally treated at 973 K for 3 h. The structural analysis for the synthesized samples was performed using XRD, high-resolution transmission electron microscopy (HRTEM), and FTIR. Scanning electron microscopy (SEM) was undertaken to explore the surface morphology of all the samples. The thermal stability of these samples was investigated using thermogravimetric analysis (TGA). XRD data show the presence of a single spinel phase for all the prepared samples. The intensity of the principal peak of the spinel phase decreases as Mg content increases, showing that Mg delays crystallinity. The Mg content raised the average grain size (D) from 0.084 µm to 0.1365 µm. TGA shows two stages of weight loss variation. The vibrating sample magnetometer (VSM) measurement shows that magnetic parameters, such as initial permeability (µi) and saturation magnetization (Ms), decay with rising Mg content. The permeability and magnetic anisotropy at different frequencies and temperatures were studied to show the samples’ magnetic behavior and determine the Curie temperature (TC), which depends on the internal structure. The electrical resistivity behavior shows the semi-conductivity trend of the samples. Finally, the dielectric constant increases sharply at high temperatures, explained by the increased mobility of charge carriers, and decreases with increasing frequency. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Princess Nourah Bint Abdulrahman University, PNU: PNURSP2022R28The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R28), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Disease prevention not decolonization: a model for fecal microbiota transplantation in patients colonized with multidrug-resistant organisms

Fecal microbiota transplantation (FMT) yields variable intestinal decolonization results for multidrug-resistant organisms (MDROs). This study showed significant reductions in antibiotic duration, bacteremia, and length of stay in 20 patients colonized/infected with MDRO receiving FMT (compared with pre-FMT history, and a matched group not receiving FMT), despite modest decolonization rates