Rheological Properties and Inkjet Printability of a Green Silver-Based Conductive Ink for Wearable Flexible Textile Antennas

The development of e-textiles necessitates the creation of highly conductive inks that are compatible with precise inkjet printing, which remains a key challenge. This work presents an innovative, syringe-based method to optimize a novel bio-sourced silver ink for inkjet printing on textiles. We investigate the relationships between inks' composition, rheological properties, and printing behavior, ultimately assessing the electrical performance of the fabricated circuits. Using Na-alginate and polyethylene glycol (PEG) as the suspension matrix, we demonstrate their viscosity depends on the component ratios. Rheological control of the silver nanoparticle-laden ink has become paramount for uniform printing on textiles. A specific formulation (3 wt.% AgNPs, 20 wt.% Na-alginate, 40 wt.% PEG, and 40 wt.% solvent) exhibits the optimal rheology, enabling the printing of 0.1 mm thick conductive lines with a low resistivity (8 × 10-3 Ω/cm). Our findings pave the way for designing eco-friendly ink formulations that are suitable for inkjet printing flexible antennas and other electronic circuits onto textiles, opening up exciting possibilities for the next generation of E-textiles.

Additive Manufacturing and Composite Materials for Marine Energy: Case of Tidal Turbine

The global trend in additive manufacturing is the technology of three-dimensional (3D) printing with a high potential to avoid some of the weaknesses of conventional fabrication techniques. This new technology has been used to manufacture small tidal and wind turbines. In isolated areas, small turbines can be manufactured and assembled on-site for green energy production. The purpose of this document is to evaluate the thermomechanical behavior of a printed tidal turbine using Digimat-AM (Additive Manufacturing) with fused filament fabrication method. The finite element computes the mechanical deflection, temperature, residual stresses, and warpage fields of the printed part. The composites used during printing are thermoplastic polymers (acrylonitrile butadiene styrene, polyamide 6 [PA6], polyamide 12 [PA12], and polyetherimide [PEI]) reinforced with carbon and glass fillers in the form of fibers and beads (CF/GF and CB/GB). Through the simulation, one could show that the blade printed with PEI-CB/CF has excellent mechanical performance of low mechanical deflection and warpage, compared to PA6-CB/CF. In addition, the fiber-shaped fillers are better than the bead-shaped ones for the 3D printing process. In general, this study has shown the potential and feasibility of 3D printing as an excellent opportunity in the fabrication of small blades in the future, but more studies are required to understand this potential.

Evaluating the Effectiveness of Interactive Virtual Patients for Medical Education in Zambia: Randomized Controlled Trial

BACKGROUND

Zambia is facing a severe shortage of health care workers, particularly in rural areas. Innovative educational programs and infrastructure have been established to bridge this gap; however, they encounter substantial challenges because of constraints in physical and human resources. In response to these shortcomings, strategies such as web-based and blended learning approaches have been implemented, using virtual patients (VPs) as a means to promote interactive learning at the Levy Mwanawasa Medical University (LMMU) in Zambia.

OBJECTIVE

This study aimed to evaluate the students' knowledge acquisition and acceptance of 2 VP medical topics as a learning tool on a Zambian higher education e-learning platform.

METHODS

Using a mixed methods design, we assessed knowledge acquisition using pre- and posttests. In a randomized controlled trial setting, students were assigned (1:1) to 2 medical topics (topic 1: appendicitis and topic 2: severe acute malnutrition) and then to 4 different learning tools within their respective exposure groups: VPs, textbook content, preselected e-learning materials, and self-guided internet materials. Acceptance was evaluated using a 15-item questionnaire with a 5-point Likert scale.

RESULTS

A total of 63 third- and fourth-year Bachelor of Science clinical science students participated in the study. In the severe acute malnutrition-focused group, participants demonstrated a significant increase in knowledge within the textbook group (P=.01) and the VP group (P=.01). No substantial knowledge gain was observed in the e-learning group or the self-guided internet group. For the appendicitis-focused group, no statistically significant difference in knowledge acquisition was detected among the 4 intervention groups (P=.62). The acceptance of learning materials exhibited no substantial difference between the VP medical topics and other learning materials.

CONCLUSIONS

In the context of LMMU, our study found that VPs were well accepted and noninferior to traditional teaching methods. VPs have the potential to serve as an engaging learning resource and can be integrated into blended learning approaches at LMMU. However, further research is required to investigate the long-term knowledge gain and the acceptance and effectiveness of VPs in medical education.

TRIAL REGISTRATION

Pan African Clinical Trials Registry (PACTR) PACTR202211594568574; https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=20413.

Development and Characterization of Phosphate Glass Fibers and Their Application in the Reinforcement of Polyester Matrix Composites

This study focused on the production and characterization of phosphate glass fibers (PGF) for application as composite reinforcement. Phosphate glasses belonging to the system 52P₂O₅24CaO13MgO (11-(X + Y)) K₂OXFe₂O₃YTiO₂ (X:1, 3, 5) and (Y:0.5, 1) were elaborated and converted to phosphate glass fibers. First, their mechanical properties and chemical durability were investigated. Then, the optimized PGF compositions were used afterward as reinforcement for thermosetting composite materials. Polyester matrices reinforced with short phosphate glass fibers (sPGF) up to 20 wt % were manufactured by the contact molding process. The mechanical and morphological properties of different sPGF-reinforced polyester systems were evaluated. The choice between the different phosphate-based glass syntheses (PGFs) was determined by their superior mechanical performance, their interesting chemical durability, and their high level of dispersion in the polyester matrix without any ad sizing as proven by SEM morphological analysis. Moreover, the characterization of mechanical properties revealed that the tensile and flexural moduli of the developed polyester-based composites were improved by increasing the sPGF content in the polymer matrix in perfect agreement with Takayanagi model predictions. The present work thus highlights some promising results to obtain high-quality phosphate glass fiber-reinforced polyester parts which can be transposed to other thermosetting or thermoplastic-based composites for high-value applications.

Extraction and characterization of Alfa fibers and their use to produce Alfa/wool woven fabrics for composite reinforcement

Because of their appealing properties, such as biodegradability, high basic stiffness, low density, and low cost, natural fibers have begun to be used in a variety of applications. In comparison to synthetics, they are also reusable. The aim of this work is to develop new woven materials made of wool and Alfa fibers (Stipa-tenacissima). The extraction of Alfa fibers was achieved via alkaline treatment. The chemical composition, mechanical and physical properties of the extracted fibers were determined. Wovens were produced using the weaving of taffetas technique. This study presents a chemical, physical, morphological and mechanical characterization of Alfa/wool yarns and fabrics. The results show that the fabric made of fibers treated with 2 mol concentration of NaOH presents the greatest morphological structure and a higher degree of crystallinity due to the reorganization of the molecular chains that results in a better orientation of the fibers compared to other concentrations. On the other hand, the results of the tensile test show that the Young’s modulus of the Alfa/Alfa woven fabric is 8 ± 1.157 MPa in the weft direction, compared to the Alfa/wool woven fabric which has 6.06 ± 0.196 MPa and wool/wool woven fabric with 14.10 ± 1.369 MPa.

Stipa tenacissima L.: A New Promising Source of Bioactive Compounds with Antioxidant and Anticancer Potentials

Background: Stipa tenacissima L. (S. tenacissima), called Esparto grass, is a cultivated species used for industrial purposes, including textile production. This species has never been studied for its medical potential before, nor has it been used in traditional medicines. It is thus fitting that the present study aimed to investigate the pharmacological potential of S. tenacissima. To achieve this goal, this work was conducted to study the chemical composition, antioxidant properties, and antiproliferative effects of S. tenacissima against cancerous cell lines, including the human colorectal adenocarcinoma cell line (HT-29) and human breast adenocarcinoma cell line (MDA-MB-231). Fractionation and characterization of S. tenacissima extract showed the presence of promising bioactive fractions. The fractions obtained from S. tenacissima extract exhibited interesting antioxidant properties, with IC₅₀ values ranging from 1.26 to 1.85 mg/mL. All fractions, such as F1, F2, F3, and F4, induced an important antiproliferative effect on the cancer cell lines MDA-MB-231, scoring IC₅₀ values ranging from 63.58 ± 3.14 to 99.880 ± 0.061 µg/mL. These fractions (F1, F2, F3, and F4) also exhibited a potent antiproliferative effect versus HT-29 cell lines, with IC₅₀ values ranging from 71.50 ± 4.97 to 87.500 ± 1.799 µg/mL. Therefore, S. tenacissima could constitute a new natural source of bioactive compounds that can be used for therapeutic purposes to fight cancer and free radical damage.

Piezo-Resistive Properties of Bio-Based Sensor Yarn Made with Sisal Fibre

In this work, a sensor yarn based on a natural sisal yarn containing a non-electro-conductive core impregnated with PVA polymer and coated by PEDOT:PSS polymer as an electro-conductive sheath was investigated. The main objectives include the development of this new sensor yarn as a first step. Then, we look towards the insertion of this sensor yarn into different woven structures followed by the monitoring of the mechanical behaviour of composite materials made with these fibrous reinforcements. The combined effect of the structural geometry and the number of PEDOT:PSS coating layers on the properties of the sensor yarns was investigated. It was found that the number of PEDOT:PSS coating layers could strongly influence the electromechanical behaviours of the sensor yarns. Different methods of characterization were employed on strain-sensor yarns with two and four coating layers of PEDOT:PSS. The piezo-resistive strain-sensor properties of these selected coating layers were evaluated. Cyclic stretching-releasing tests were also performed to investigate the dynamic strain-sensing behavior. The obtained results indicated that gauge factor values can be extracted in three strain regions for two and four coating layers, respectively. Moreover, these strain-sensor yarns showed accurate and stable sensor responses under cyclic conditions. Furthers works are in progress to investigate the mechanism behind these first results of these sisal fibre-based sensors.

[Uveitic glaucoma in Behçet's disease: When everything gets complicated]

INTRODUCTION

Behçet's disease is a systemic disease of unknown etiology. Its ocular manifestations are multiple and polymorphic, with uveitis at the top of the list. Classically, uveitis in Behçet's disease does not cause elevation of intraocular pressure. However, this may be found in 10 to 20% of cases, secondary to trabeculitis, trabecular obstruction by inflammatory cells, anterior or posterior synechiae, or induced by prolonged use of corticosteroids. Its occurrence is a major complication, the management of which is especially delicate when glaucoma occurs. The purpose of this study was to study the factors predictive of glaucoma in Behçet's disease.

MATERIALS AND METHODS

This is a retrospective study of all the charts of patients consecutively hospitalized for Behçet's disease over a period of 8years in the ophthalmology A department of the specialty hospital of Rabat university medical center.

RESULTS

Fifty patients were treated for Behçet's disease during the study period. There were 41 men (82%), and 9 women (18%). Glaucoma was diagnosed in 11 patients (22%). The mean age of this subgroup was 31years, with a gender ratio of 6 women/5 men. The glaucoma was associated with anterior synechiae in 4 cases, primary open-angle glaucoma in 5 cases, neovascular glaucoma in 1 case and seclusio pupillae in 1 case. Therapeutically, all patients were on glaucoma eye drops, and five underwent filtering surgery. Statistically, on univariate analysis, ocular hypertension was observed particularly in patients with low initial visual acuity (less than 1/10) (P=0.001), with severe posterior segment involvement, especially retinal vasculitis (29% vs. 6%, P=0.04), macular edema (40% vs. 4%, P=0.001), and optic disc edema (50% vs. 15%, P=0.02). A high number of recurrences was also associated with glaucoma (1.0 vs. 3.0, P<0.0001). On multivariate analysis, low baseline visual acuity, presence of retinal vasculitis, and high number of recurrences were independent risk factors for ocular hypertension in our patients followed for Behçet's disease.

CONCLUSION

Glaucoma can complicate the management of Behçet's disease. This glaucoma will be more difficult to manage in this delicate pathological context. It requires special vigilance in patients with severe posterior segment inflammation, to institute effective management to avoid its potentially blinding complications.

Rheological and Electrical Study of a Composite Material Based on an Epoxy Polymer Containing Cyclotriphosphazene

In this work, we have studied, formulated, prepared, and characterized the rheological and electrical behavior of a composite material based on an epoxy resin Diglycidyl Ether of Bisphenol A (DGEBA) reinforced with hexaglycidyl cyclotriphosphazene (HGCP). The epoxy system was cured with 4,4’-methylene dianiline (MDA). DGEBA-HGCP-MDA epoxy composite materials with reinforced HGCP which varied from 5% to 10% by weight were prepared by mixing in the molten state. The morphology was evaluated by SEM. The rheological behavior was studied using small deformation rheology. The electrical characterization was carried out with a frequency variation range from 1 Hz to 100 KHz at room temperature. These measurements revealed that the rheological and electrical behaviors strongly depend on the quantity of HGCP in the DGEBA matrix. The linear viscoelastic properties study reveals that the modulus of elasticity G’ is dependent on the amount of HGCP present in the epoxy resin DGEBA. The capacitance-frequency measurements suggest a distribution of localized states in the band gap of the blends.

Clinical and therapeutic features of pediatric Vogt-Koyanagi-Harada disease

PURPOSE

To analyze clinical, therapeutic and prognostic features of pediatric Vogt-Koyanagi-Harada (VKH) disease.

MATERIAL AND METHODS

This retrospective study included 16 eyes of 8 children diagnosed with VKH disease followed at a teaching hospital over a 10 year period. Diagnosis was based on the revised criteria of VKH disease. All data were analyzed using SPSS® software.

RESULTS

There were 62.5% girls and 37.5% boys. The mean age (years) was 14.6±4.4. The mean follow-up (months) was 38.7±28.7. The mean initial visual acuity (VA) (LogMAR) was 1.4 with 68.8% of eyes presenting with severe visual loss at admission. The median time (days) required for resorption of the serous retinal detachment was 10 [8.25-25]. Extraocular signs were present in 62.5% of cases. The mean time until initiation of treatment was 25.6 days. 62.5% of patients received corticosteroids alone, and 37.5% of patients received a combination of corticosteroids and immunosuppressive therapy. Final VA was 0.4 [0.1-2.3]. In our study, the time until consultation, low initial VA and recurrences were statistically associated with severe visual loss (P≤0.05).

CONCLUSION

Life expectancy in pediatric cases of VKH disease justifies the early initiation of immunosuppressive treatment or even biological therapy to achieve better steroid sparing and preserve visual function.

Flocculation monitoring of wastewater by using impedance spectroscopy

The aim of the present work is to monitor the flocculation process using the analysis of the electric and dielectric properties. Therefore the dielectric and electrical characteristics of wastewater with different cationic polymer concentrations were investigated via the impedance spectroscopy (IS) method. Impedance measurements were carried at different concentration of cationic polymer in the frequency range from 0.1 Hz to 100 kHz. The analysis of complex permittivity spectra was described by the superposition of a power law at a low frequency related to the diffusion process and Cole-Cole relaxation behavior at high frequency. Moreover, an equivalent circuit model was developed in order to analyze the experimental data and to further investigate both processes. The variation of the parameters extracted from the equivalent circuit with the increase of cationic polymer concentrations has shown a net transition at 10 mg/l. This behavior could reflect the flocculation of dispersed particles at 10 mg/l. The findings in this work could draw new attention toward the monitoring of the coagulation-flocculation process using impedance spectroscopy and could be extended to other kinds.

Textile finishing dyes and their impact on aquatic environs

In the present review, we have been able to describe the different families of dyes and pigments used in textile finishing processes (Yarns, fabrics, nonwovens, knits and rugs) such as dyeing and printing. These dyes are reactive, direct, dispersed, indigo, sulphur and vats. Such that their presence in the liquid effluents resulting from the textile washing constitutes a serious risk, in the absence of their purification, for the quality of receiving aquatic environments. Indeed, the presence of these dyes and pigments can cause a significant alteration in the ecological conditions of the aquatic fauna and flora, because of the lack of their biodegradability. This has a negative impact on the equilibrium of the aquatic environment by causing serious dangers, namely the obvious dangers (Eutrophication, under-oxygenation, color, turbidity and odor), the long-term dangers (Persistence, bioaccumulation of carcinogenic aromatic products and formation of by-products of chlorination), mutagenicity and carcinogenicity.