Synthesis, molecular modelling and evaluation of larvicidal efficacy of annulated Benzo[h]chromenes against Culex pipiens L. Larvae.

A new series of substituted benzo[h]chromene, benzochromenopyrimidine, and benzochromenotriazolopyrimidine derivatives were synthesized via chemical transformations of iminonitrile, ethoxymethylene amino, and cyanomethylene functionalities. The chemical structures of the synthesized compounds were assured by spectroscopic data and elemental analysis. The larvicidal efficacy of these compounds against Culex pipiens L. larvae was investigated, revealing potent insecticidal activity, particularly for compounds 6, 10, and 16, exceeding that of the standard insecticide chlorpyrifos. The mode of action of these compounds was explored through molecular docking studies, indicating their potential as acetylcholine esterase (AChE) inhibitors and nicotinic acetylcholine receptors (nAChR) blockers. The structure-activity relationship analysis highlighted the influence of substituents and fused heterocyclic rings on larvicidal potency. These findings suggest that the synthesized compounds hold promise as potential candidates for developing novel and effective mosquito control agents.

Hybrid nanoparticles combining nanoselenium-mediated Carica papaya extract and trimethyl chitosan for combating clinical multidrug-resistant bacteria.

Multidrug-resistant bacterial infections pose a significant threat to human health, prompting the exploration of innovative solutions. In this study, a new series of antibacterial hybrid nanoparticles (HNPs) were developed. The HNPs are based on a combination of selenium nanoparticles (SeNPs), synthesized using Carica papaya leaf extract, and chitosan (CS/SeHNPs) or trimethyl chitosan (TMC/SeHNPs), respectively. Comprehensive characterization using UV-Vis, FTIR, XRD, SEM-EDX, DLS, TEM, and DSC confirmed the structure and properties of the developed HNPs. SeNPs, CS/SeHNPs, and TMC/SeHNPs showed average hydrodynamic size of 78.8, 91.3, and 122 nm, and zeta potentials of -6.35 mV, +32.8 mV, and +54.8 mV, respectively. Biological assessments were conducted, including antibacterial and antibiofilm assays against clinical strains (E. coli, S. aureus, and K. pneumoniae), along with antioxidant activity. TMC/SeHNPs demonstrated superior performance compared to SeNPs and CS/SeHNPs with the lowest minimum inhibition concentrations (MIC) against S. aureus and K. pneumoniae (3.9 µg/mL) and 62.5 µg/mL against E. coli in addition to robust antibiofilm activity. Furthermore, the TMC/SeHNPs exhibited potent DPPH free radical scavenging ability and demonstrated good biocompatibility, as evidenced by cell viability assays on HFB4 cells. Overall, TMC/SeHNPs emerged as promising candidates in nanomedicine, offering high antioxidant, antibacterial, and antibiofilm activities alongside excellent biocompatibility.

Individual or successiveseed priming with nitric oxide and calcium toward enhancing salt tolerance of wheat crop through early ROS detoxification and activation of antioxidant defense.

Despite the considerable efforts reported so far to enhance seed priming, novel ideas are still needed to be suggested to this sustainable sector of agri-seed industry. This could be the first study addressing the effect of nitric oxide (NO) under open field conditions. The impacts of seed redox-priming using sodium nitroprusside (SNP) and osmo-priming with calcium chloride (CaCl2), both applied individually or successively, were investigated under salinity stress conditions on wheat plants (Triticum aestivum L.). Various parameters, including water relations, growth, yield, photosynthetic pigments, and antioxidant activities (enzymatic and non-enzymatic), were recorded to assess the outcomes of these priming agents on mitigating the negative impacts of salinity stress on wheat plants. Water consumptive use (ETa) and irrigation water applied (IWA) decreased with seeds priming. Successive priming with SNP + CaCl2 induced the greatest values of crop water productivity (CWP), irrigation water productivity (IWP), seed index, grain yield and grain nitrogen content.Under salinity stress, the dry weight of plants was decreased. However, hydro-priming and successive chemical priming agents using combinations of calcium chloride and sodium nitroprusside (CaCl2 + SNP & SNP + CaCl2) preserved growth under salinity stress.Individual priming with sodium nitroprusside (SNP) and calcium chloride (CaCl2) resulted in the lowest recorded content of sodium in the shoot, with a value of 2 ppm. On the other hand, successive priming using CaCl2 + SNP or SNP + CaCl2 induced the contents of potassium in the shoot, with values of 40 ppm and 39 ppm, respectively. Malondialdehyde decreased in shoot significantly withapplicationof priming agents. Successive priming with CaCl2 + SNP induced the highest proline contents in shoot (6 µg/ g FW). The highest value of phenolics and total antioxidants contents in shoot were recorded under successive priming using CaCl2 + SNP and SNP + CaCl2.Priming agents improved the activities of ascorbate peroxidase and catalase enzymes. The successive priming improved water relations (ETa, IWA, CWP and IWP) and wheat growth and productivity under salinity stress more than individual priming treatments.

Designing Lightweight 3D-Printable Bioinspired Structures for Enhanced Compression and Energy Absorption Properties.

Recent progress in additive manufacturing, also known as 3D printing, has offered several benefits, including high geometrical freedom and the ability to create bioinspired structures with intricate details. Mantis shrimp can scrape the shells of prey molluscs with its hammer-shaped stick, while beetles have highly adapted forewings that are lightweight, tough, and strong. This paper introduces a design approach for bioinspired lattice structures by mimicking the internal microstructures of a beetle's forewing, a mantis shrimp's shell, and a mantis shrimp's dactyl club, with improved mechanical properties. Finite element analysis (FEA) and experimental characterisation of 3D printed polylactic acid (PLA) samples with bioinspired structures were performed to determine their compression and impact properties. The results showed that designing a bioinspired lattice with unit cells parallel to the load direction improved quasi-static compressive performance, among other lattice structures. The gyroid honeycomb lattice design of the insect forewings and mantis shrimp dactyl clubs outperformed the gyroid honeycomb design of the mantis shrimp shell, with improvements in ultimate mechanical strength, Young's modulus, and drop weight impact. On the other hand, hybrid designs created by merging two different designs reduced bending deformation to control collapse during drop weight impact. This work holds promise for the development of bioinspired lattices employing designs with improved properties, which can have potential implications for lightweight high-performance applications.

Multi-decadal coastal change detection using remote sensing: the Mediterranean coast of Egypt between El-Dabaa and Ras El-Hekma.

A key source of information for many decision support systems is identifying land use and land cover (LULC) based on remote sensing data. Land conservation, sustainable development, and water resource management all benefit from the knowledge obtained from detecting changes in land use and land cover. The present study aims to investigate the multi-decadal coastal change detection for Ras El-Hekma and El-Dabaa area along the Mediterranean coast of Egypt, a multi-sectoral development area. Besides, the superiority of the area is highly dependent on its proximity to three development projects: the tourism and urban growth pole at Ras El-Hekma, the beachfront Alamain New Mega City, and the Nuclear Power Plant at El Dabaa. This study utilized multi-spectral Landsat satellite images covering 1990, 2010, and 2020 to perceive the post-classification change detection analysis of the land use and land cover changes (LULCC) over 30 years. The results of the supervised classification from 1990 to 2020 showed a 47.33 km2 (4.13%) expansion of the agricultural land area, whereas the bare soil land area shrunk to 73.13 km2 (6.24%). On the other hand, the built-up activities in the area launched in 2010 and escalated to 20.51 km2(1.77%) in 2020. The change in land use reveals the shift in the economic growth pattern in the last decade toward tourism and urban development. Meanwhile, it indicates that no conflict has yet arisen regarding the land use between the expanded socioeconomic main sectors (i.e., agriculture, and tourism). Therefore, the best practices of land use management and active participation of the stakeholders and the local community should be enhanced to achieve sustainability and avoid future conflicts. An area-specific plan including resource conservation measures and the provision of livelihood alternatives should be formulated within the National Integrated Coastal Zone Management (ICZM) plan with the participation of the main stakeholders and beneficiaries. The findings of the present work may be considered useful for sustainable management and supportive to the decision-making process for the sustainable development of this area.

Improving the physicochemical and antioxidative properties of fermented goat milk using carob molasses and some probiotic strains.

Fermented goat milk samples, processed by adding 0, 2, and 4% carob molasses, and Bifidobacterium bifidum DSMZ or Lactobacillus helveticus CH5, were evaluated for their physicochemical, antioxidative, and sensory properties along with probiotic viability during storage. pH and viscosity gradually decreased over the storage period whereas their values increased with the increased amount of carob molasses. Bifidobacterium bifidum DSMZ or Lactobacillus helveticus CH5 kept higher viable numbers. Lactobacillus helveticus CH5 strain recorded higher viability. Increasing the added amount of carob molasses increased the total phenolic content, which in turn is reflected in the increase in antioxidant activity. Adding carob molasses participated in the partial masking of the goaty flavor and had no significant effect on the product's acceptability, which was strongly influenced by the progress of cold storage. Therefore, fermented goat milk described by its enhanced physicochemical and antioxidative properties could be obtained by adding carob molasses and probiotics. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01382-2.

Nutrigenomics and microbiome shaping the future of personalized medicine: a review article.

The relationship between nutrition and genes has long been hinted at and sometimes plainly associated with certain diseases. Now, after many years of research and coincidental findings, it is believed that this relationship, termed "Nutrigenomics," is certainly a factor of major importance in various conditions. In this review article, we discuss nutrigenomics, starting with basics definitions and enzymatic functions and ending with its palpable association with cancer. Now, diet is basically what we eat on a daily basis. Everything that enters through our alimentary tract ends up broken down to minute molecules and amino acids. These molecules interact with our microbiome and genome in discreet ways. For instance, we demonstrate how proper intake of probiotics enhances beneficial bacteria and may alleviate IBS and prevent colorectal cancer on the long term. We also show how a diet rich in folic acid is essential for methylenetetrahydrofolate reductase (MTHFR) function, which lowers risk of colorectal cancer. Also, we discuss how certain diets were associated with development of certain cancers. For example, red and processed meat are highly associated with colorectal and prostate cancer, salty diets with stomach cancer, and obesity with breast cancer. The modification of these diets significantly lowered the risk and improved prognosis of these cancers among many others. We also examined how micronutrients had a role in cancer prevention, as vitamin A and C exert anti-carcinogenic effects through their function as antioxidants. In addition, we show how folic acid prevent DNA mutations by enhancing protein methylation processes. Finally, after a systematic review of myriad articles on the etiology and prevention of cancer, we think that diet should be a crucial feature in cancer prevention and treatment programs. In the future, healthy diets and micronutrients may even be able to successively alter the liability to genetic mutations that result in cancer. It also will play a role in boosting treatment and improving prognosis of diagnosed cancers.

Linking Cognitive Impairment with Amyloid-ß Accumulation in Alzheimer's Disease: Insights from Behavioral Tests and FTIR Spectroscopy.

Background: Alzheimer's disease (AD) is a neurodegenerative disorder that progresses over time. Fourier Transform Infrared Spectroscopy (FTIR) analysis gives identification of the main metabolic changes that happen during neurodegeneration, by monitoring biochemical and molecular structure alterations that can help in AD diagnosis or treatment approach. Objective: The aim of the present work is to assess AD hallmarks in molecular structure of retina and monitor accumulation of amyloid beta42(Aß42) in brain and retina during disease progression. Methods: AD induced in rats by Aluminum Chloride (AlCl3). Retinal molecular structure during disease progression for 2,4,6 and 8 weeks was assessed by Fourier-transform infrared spectroscopy (FTIR) and the incidence of the disease was confirmed by a behavioural assessment; the Morris Water Maze test. Aß42 levels in the brain and retina were also measured. Results: The results indicated that cognitive impairment starting from 6 weeks of AlCl3 administration. Retinal concentration of Aß42 was significant increase (p < 0.05) from 2 weeks that precedes the observed increase of Aß42 in the brain which appeared after 4 weeks of AlCl3 administration. Multivariate principal component analysis discovers that the variance noticed in the infrared spectra due to AD condition and it is time dependent for progression of the disease. Conclusions: The accumulation of Aß42 is a sensitive early biomarker in retina for AD. FTIR analysis of the retina revealed changes in hydrogen bond formation or destruction, alterations in lipid chain length and branching accompanied by depleted lipid content and carbonization, as well as degeneration of the retinal tissue due to AD.

Fortification of Fermented Camel Milk with Salvia officinalis L. or Mentha piperita Leaves Powder and Its Biological Effects on Diabetic Rats.

The incorporation of fermented camel milk with natural additives possesses numerous benefits for the treatment of various pathological and metabolic conditions. The present study investigated the impact of fortification of fermented camel milk with sage or mint leaves powder (1 and 1.5%, respectively) on glucose and insulin levels, lipid profile, and liver and kidney functions in alloxan-induced diabetic rats. The gross chemical composition of sage and peppermint leaves powder was studied. The chemical composition of sage and mint extracts was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS) of sage and mint extracts. Furthermore, a total of forty-two adult normal male albino rats were included in this study, whereas one group was kept as the healthy control group (n = 6 rats) and diabetes was induced in the remaining animals (n = 36 rats) using alloxan injection (150 mg/kg of body weight). Among diabetic rats groups, a control group (n = 6 rats) was kept as the diabetic control group whereas the other 5 groups (6 rats per group) of diabetic rats were fed fermented camel milk (FCM) or fermented camel milk fortified with 1 and 1.5% of sage or mint leaves powder. Interestingly, the oral administration of fermented camel milk fortified with sage or mint leaves powder, at both concentrations, caused a significant decrease in blood glucose level and lipid profile, and an increase in insulin level compared to the diabetic control and FCM groups. Among others, the best results were observed in the group of animals that received fermented camel milk fortified with 1.5% sage powder. In addition, the results revealed that the fermented camel milk fortified with sage or mint leaves powder improved the liver and kidney functions of diabetic rats. Our study concluded that the use of sage and mint leaves powder (at a ratio of 1.5%) with fermented camel milk produces functional food products with anti-diabetic activity.

Optimising Surface Roughness and Density in Titanium Fabrication via Laser Powder Bed Fusion.

The Ti6Al4V alloy has many advantages, such as being lightweight, formal, and resistant to corrosion. This makes it highly desirable for various applications, especially in the aerospace industry. Laser Powder Bed Fusion (LPBF) is a technique that allows for the production of detailed and unique parts with great flexibility in design. However, there are challenges when it comes to achieving high-quality surfaces and porosity formation in the material, which limits the wider use of LPBF. To tackle these challenges, this study uses statistical techniques called Design of Experiments (DoE) and Analysis of Variance (ANOVA) to investigate and optimise the process parameters of LPBF for making Ti6Al4V components with improved density and surface finish. The parameters examined in this study are laser power, laser scan speed, and hatch space. The optimisation study results show that using specific laser settings, like a laser power of 175 W, a laser scan speed of 1914 mm/s, and a hatch space of 53 µm, produces Ti6Al4V parts with a high relative density of 99.54% and low top and side surface roughness of 2.6 µm and 4.3 µm, respectively. This promising outcome demonstrates the practicality of optimising Ti6Al4V and other metal materials for a wide range of applications, thereby overcoming existing limitations and further expanding the potential of LPBF while minimising inherent process issues.

Hybrid Finite Element-Smoothed Particle Hydrodynamics Modelling for Optimizing Cutting Parameters in CFRP Composites.

Carbon-fibre-reinforced plastic (CFRP) is increasingly being used in various applications including aerospace, automotive, wind energy, sports, and robotics, which makes the precision modelling of its machining operations a critical research area. However, the classic finite element modelling (FEM) approach has limitations in capturing the complexity of machining, particularly with regard to the interaction between the fibre-matrix interface and the cutting edge. To overcome this limitation, a hybrid approach that integrates smoothed particle hydrodynamics (SPHs) with FEM was developed and tested in this study. The hybrid FEM-SPH approach was compared with the classic FEM approach and validated with experimental measurements that took into account the cutting tool's round edge. The results showed that the hybrid FEM-SPH approach outperformed the classic FEM approach in predicting the thrust force and bounce back of CFRP machining due to the integrated cohesive model and the element conversion after failure in the developed approach. The accurate representation of the fibre-matrix interface in the FEM-SPH approach resulted in predicting precise chip formation in terms of direction and morphology. Nonetheless, the computing time of the FEM-SPH approach is higher than the classic FEM. The developed hybrid FEM-SPH model is promising for improving the accuracy of simulation in machining processes, combining the benefits of both techniques.

A novel protective modality against rotenone-induced Parkinson's disease: A pre-clinical study with dulaglutide.

Parkinson's disease (PD) drugs treat symptoms without inhibiting progression. In recent years, finding novel therapeutic medications that can halt disease progression has become crucial. Research on antidiabetic medicines is valuable in these investigations because of the parallels between the two disorders. Using Rotenone (ROT), a frequently used PD model, the possible neuroprotective benefits of Dulaglutide (DUL), an extended-acting glucagon-like peptide-1 agonist, were considered. Twenty-four rats were randomly assigned to 4 groups to complete this experiment (n = 6). 0.2 ml of the vehicle (1 ml of dimethyl sulfoxide (DMSO) diluted in sunflower oil) was administered to the standard control group subcutaneously with a 48-hour pause. The second group was administered ROT 2.5 mg/kg SC every 48 h for 20 days as a positive control group. The third and fourth groups were administered one dose of DUL each week (0.05 and 0.1 mg/kg SC, respectively) to their regimens. The mice received ROT (2.5 mg/kg SC) every 48 h for 20 days after receiving DUL for the initial dose (96 h later). The current study focused on the DUL's ability to preserve usual behavioral function, enhance antioxidant and anti-inflammatory pathways, inhibit alpha-synuclein (α-syn), and increase parkin levels. It is concluded that DUL acts as an antioxidant and an anti-inflammatory to protect against ROT-induced PD. However, more studies are required to support this finding.

Chip Formation and Orthogonal Cutting Optimisation of Unidirectional Carbon Fibre Composites.

This study presents a thorough experimental investigation utilising the design of experiments and analysis of variance (ANOVA) to examine the impact of machining process parameters on chip formation mechanisms, machining forces, workpiece surface integrity, and damage resulting from the orthogonal cutting of unidirectional CFRP. The study identified the mechanisms behind chip formation and found it to significantly impact the workpiece orientation of fibre and the tool's cutting angle, resulting in increased fibre bounceback at larger fibre orientation angles and when using smaller rake angle tools. Increasing the depth of cut and fibre orientation angle results in an increased damage depth, while using higher rake angles reduces it. An analytical model based on response surface analysis for predicting machining forces, damage, surface roughness, and bounceback was also developed. The ANOVA results indicate that fibre orientation is the most significant factor in machining CFRP, while cutting speed is insignificant. Increasing fibre orientation angle and depth leads to deeper damage, while larger tool rake angles reduce damage. Machining workpieces with 0° fibre orientation angle results in the least subsurface damage, and surface roughness is unaffected by the tool rake angle for fibre orientations between 0° to 90° but worsens for angles greater than 90°. Optimisation of cutting parameters was subsequently carried out to improve machined workpiece surface quality and reduce forces. The experimental results showed that negative rake angle and cutting at moderately low speeds (366 mm/min) are the optimal conditions for machining laminates with a fibre angle of θ = 45°. On the other hand, for composite materials with fibre angles of θ = 90° and θ = 135°, it is recommended to use a high positive rake angle and cutting speeds.

Prognosis of Biomarker of Alzheimer's Disease in the Function of the Retina and Secondary Molecular Structure Variation of the Retina and Brain.

Alzheimer's disease (AD) is one of the most serious neurodegenerative diseases in the globe. As a result, there is an acute need to discover indications that allow for early disease detection. There is growing scientific data showing the similarities between the eye and other central nervous system components, suggesting that information obtained in ophthalmic research might be valuable in the study and diagnosis of AD. Fifty male albino Wistar rats were separated into five groups: the first group served as control, and the other four groups of animals were administrated aluminium chloride (AlCl3) in a dose of 100 mg/kg body weight (b.w.) for 2, 4, 6, and 8 weeks, respectively. Insights into the function of the retina by electroretinogram (ERG) and the changes thought to have occurred in the molecular structure of the retina and brain using Fourier transform infrared spectroscopy (FTIR) as a result of AD progression induced by AlCl3 in rats were done. Moreover, the measurement of acetylcholinesterase (AchE) was done. After 6 and 8 weeks of AlCl3 injection, there was a substantial reduction (p ≤ 0.05) in a- and b-wave amplitudes and a significant rise (p ≤ 0.05) in implicit time compared to controls. A significant elevation (p ≤ 0.05) of AchE content was observed after 4, 6, and 8 weeks. FTIR revealed a significant increase (p ≤ 0.05) of ß-turn and ß-sheet content associated with significant decrease (p ≤ 0.05) of α-helix content for all groups administrated with AlCl3. Our findings suggest that retinal biomarkers such as ERG of the retina may be used as a screening tool for detection of AD. Secondary structural changes in the proteins of the retina and the brain were similar in AD rats' model and precede retinal dysfunction.

Synthesis, larvicidal efficiency and molecular docking studies of novel annulated pyrano[2,3-c]pyrazoles against Culex pipiens L. and Musca domestica L. larvae.

A number of novel annulated pyrazolopyranopyrimidines were prepared via reaction of iminoether of the corresponding 6-amino-5-cyano-pyrano[2,3-c]pyrazole derivative 1 with different nitrogen nucleophiles. The structure of the synthesized compounds was deduced based on IR, MS, 1H NMR and 13C NMR spectroscopic data. The larvicidal potency of the synthesized compounds against the lab and field strains of Culex pipiens and Musca domestica larvae was evaluated and the structure-activity relationship (SAR) was discussed. The assay revealed that the tested pyranopyrazole derivatives exhibited good larvicidal bio-efficacy whereas iminoether 4 exhibited the highest efficiency, for lab more than field strains of both species. Also, M. domestica larvae were more sensitive to tested compounds than C. pipiens. The field strain showed low resistance ratios to all compounds with only about 2 folds. The inhibitory effects of synthesized molecules on nAChRs were evaluated by molecular docking. Moreover, the cytotoxicity of the newly synthesized compounds against normal human fibroblasts (WI-38) was investigated. The cytotoxic assay showed that derivatives 4 and 5 were not harmful to normal fibroblasts.

Empagliflozin attenuates neurodegeneration through antioxidant, anti-inflammatory, and modulation of α-synuclein and Parkin levels in rotenone-induced Parkinson's disease in rats.

Sodium-glucose co-transporter 2 (SGLT 2) inhibitors are a relatively new antidiabetic drug with antioxidant and anti-inflammatory properties. Therefore, this study aimed to investigate whether SGLT 2 inhibitors have a neuroprotective effect in PD. Twenty-four Wistar rats were randomized into four groups. The first one (control group) received dimethyl sulfoxide (DMSO) as a vehicle (0.2 mL/48 hr, S.C). The second group (positive control) received rotenone (ROT) (2.5 mg/kg/48 hr, S.C) for 20 successive days, whereas the third and fourth groups received empagliflozin (EMP) (1 and 2 mg/kg/day, orally), respectively. The two groups received rotenone (2.5 mg/kg/48 hr S.C) concomitantly with EMP for another 20 days on the fifth day. By the end of the experimental period, behavioral examinations were done. Subsequently, rats were sacrificed, blood samples and brain tissues were collected for analysis. ROT significantly elevated oxidative stress and proinflammatory markers as well as α-synuclein. However, dopamine (DP), antioxidants, tyrosine hydroxylase (TH), and Parkin were significantly decreased. Groups of (EMP + ROT) significantly maintained oxidative stress and inflammatory markers elevation, maintained α-synuclein and Parkin levels, and elevated TH activity and dopamine level. In both low and high doses, EMP produced a neuroprotective effect against the PD rat model, with the high dose inducing a more significant effect.

Simple simultaneous determination of moxifloxacin and metronidazole in complex biological matrices.

A simple, sensitive and rapid RP-HPLC method is presented, for the first time, for the simultaneous determination of moxifloxacin hydrochloride and metronidazole in different biological fluids including saliva and plasma without any matrix interference. The separation was performed using ACN and phosphate buffer (30 : 70% v/v) as the mobile phase on a Zorbax Eclipse Plus-C18 column attached to a guard column. The method was validated according to the FDA guidelines for bioanalytical method validation and was successfully applied for simultaneous determination of the studied drugs in saliva and plasma samples. The good precision and selectivity of the developed method allow it to be used for routine therapeutic drug monitoring of such drugs and it presents a simple and sensitive analytical tool for performing versatile pharmacokinetics and bioavailability studies. A DAD detector is valuable to determine each drug at its maximum wavelength to ensure high sensitivity. Determination of such a combination in saliva introduces a quick and non-invasive alternative to blood analysis.

Fabrication and Optimisation of Ti-6Al-4V Lattice-Structured Total Shoulder Implants Using Laser Additive Manufacturing.

This work aimed to study one of the most important challenges in orthopaedic implantations, known as stress shielding of total shoulder implants. This problem arises from the elastic modulus mismatch between the implant and the surrounding tissue, and can result in bone resorption and implant loosening. This objective was addressed by designing and optimising a cellular-based lattice-structured implant to control the stiffness of a humeral implant stem used in shoulder implant applications. This study used a topology lattice-optimisation tool to create different cellular designs that filled the original design of a shoulder implant, and were further analysed using finite element analysis (FEA). A laser powder bed fusion technique was used to fabricate the Ti-6Al-4V test samples, and the obtained material properties were fed to the FEA model. The optimised cellular design was further fabricated using powder bed fusion, and a compression test was carried out to validate the FEA model. The yield strength, elastic modulus, and surface area/volume ratio of the optimised lattice structure, with a strut diameter of 1 mm, length of 5 mm, and 100% lattice percentage in the design space of the implant model were found to be 200 MPa, 5 GPa, and 3.71 mm-1, respectively. The obtained properties indicated that the proposed cellular structure can be effectively applied in total shoulder-replacement surgeries. Ultimately, this approach should lead to improvements in patient mobility, as well as to reducing the need for revision surgeries due to implant loosening.

2021 NATIONAL DIAGNOSTIC REFERENCE LEVELS FOR PAEDIATRIC COMPUTED TOMOGRAPHY IN EGYPT.

OBJECTIVE: To establish national diagnostic reference levels (NDRLs) for most common paediatric computed tomography (CT) examinations in Egypt. METHODS: This was a prospective study that included all dedicated paediatric imaging centers in Egypt. Data from 1680 individual paediatric patients undergoing CT scanning of the head, chest and abdomen-pelvis were collected. Computed tomography dose indices were recorded, data were analysed and compared with the internationally published paediatric DRLs in14 countries. RESULTS: The Egyptian NDRLs of the CTDIvol (mGy) for head, chest and abdomen-pelvis scans among four paediatric age groups were found to be (23, 27, 28, 32, 4, 5, 6, 8, 5, 6, 7, 9) mGy, respectively; and the corresponding NDRLs of the DLP (mGycm) for head, chest and abdomen-pelvis scans were found to be (345, 428, 499, 637, 67, 85, 145, 215, 97, 135, 240, 320) mGycm, respectively. There were variations in the radiation doses between CT centers and identical scanners indicating the need for dose optimization. The NDRLs of the CTDIvol (mGy) and the DLP (mGycm) values were similar to or lower than international DRLs. CONCLUSION: This study summarizes the results of the first Egyptian Computed Tomography survey that provides national diagnostic reference levels for paediatric patients in Egypt. Despite the reasonable NDRLs values, the study depicted certain pros and cons concerning CT practice, and identified some problems that hinder the process of optimization as well as justification in children.

Multistage Tool Path Optimisation of Single-Point Incremental Forming Process.

Single-point incremental forming (SPIF) is a flexible technology that can form a wide range of sheet metal products without the need for using punch and die sets. As a relatively cheap and die-less process, this technology is preferable for small and medium customised production. However, the SPIF technology has drawbacks, such as the geometrical inaccuracy and the thickness uniformity of the shaped part. This research aims to optimise the formed part geometric accuracy and reduce the processing time of a two-stage forming strategy of SPIF. Finite element analysis (FEA) was initially used and validated using experimental literature data. Furthermore, the design of experiments (DoE) statistical approach was used to optimise the proposed two-stage SPIF technique. The mass scaling technique was applied during the finite element analysis to minimise the computational time. The results showed that the step size during forming stage two significantly affected the geometrical accuracy of the part, whereas the forming depth during stage one was insignificant to the part quality. It was also revealed that the geometrical improvement had taken place along the base and the wall regions. However, the areas near the clamp system showed minor improvements. The optimised two-stage strategy successfully decreased both the geometrical inaccuracy and processing time. After optimisation, the average values of the geometrical deviation and forming time were reduced by 25% and 55.56%, respectively.