Chitosan/functionalized fruit stones as a highly efficient adsorbent biomaterial for adsorption of brilliant green dye: Comprehensive characterization and statistical optimization.

In this research, a highly efficient adsorbent biomaterial (hereinafter, CTS/PPS-HS) of chitosan/functionalized fruit stones (peach and plum) with H2SO4 was produced for the adsorption of brilliant green (BG) dye from aquatic systems. The developed biomaterial was characterized by several techniques like SEM-EDX, FTIR, XRD, BET, and pHpzc. To systematically optimize the adsorption performance of CTS/PPS-HS, the Box-Behnken design (BBD) based on response surface methodology (RSM) was attained. The factors considered for optimization included A: CTS/PPS-HS dosage (0.02-0.08 g), B: pH (4-10), and C: removal time (10-60 min). The pseudo-first-order and Langmuir isotherm models exhibited excellent agreement with the experimental results of BG adsorption by CTS/PPS-HS. The outstanding adsorption capacity (409.63 mg/g) of CTS/PPS-HS was obtained. The remarkable adsorption of BG onto CTS/PPS-HS can be primarily attributed to electrostatic forces between the acidic sites of CTS/PPS-HS and the BG cations, accompanied by interactions such as π-π, Yoshida H-bonding, n-π, and H-bond interactions. The current data underscores the significant potential inherent in combining biomass with CTS polymer to create an exceptionally effective adsorbent biomaterial tailored for the elimination of cationic dyes.

Development of chitosan biopolymer by chemically modified orange peel for safranin O dye removal: A sustainable adsorbent and adsorption modeling using RSM-BBD.

This study aimed to develop a biocomposite (hereinafter, CHI/OP-H2SO4) via the functionalization of chitosan (CHI) biopolymer by chemically modified orange peel (OP-H2SO4). The physicochemical characteristics of CHI/OP-H2SO4 were studied using methods such as pHpzc, XRD, FTIR, BET, and FESEM-EDX. The efficacy of the CHI/OP-H2SO4 biocomposite in removing cationic dye (safranin O, SAF-O) from aqueous solutions was assessed. The Box-Behnken Design (BBD) based on response surface methodology (RSM) was employed to optimize the adsorption performance of CHI/OP-H2SO4, considering factors such as A: CHI/OP-H2SO4 dose (0.02-0.08 g), B: pH (4-10), and C: time (10-60 min). The pseudo-first-order and Freundlich isotherm models align well with the experimental data of SAF-O adsorption by CHI/OP-H2SO4. The excellent adsorption capacity for CHI/OP-H2SO4 was recorded (321.2 mg/g). The notable adsorption of SAF-O onto CHI/OP-H2SO4 is attributed primarily to electrostatic forces between the acidic groups of CHI/OP-H2SO4 and the SAF-O cation, along with H-bonding, and n-π interactions. By transforming waste materials into valuable resources, this approach not only mitigates environmental impact but also produces a promising and sustainable adsorbent for the removal of cationic dyes, exemplified here by the effective removal of SAF-O dye.

Mapping the Private Healthcare Sector in Riyadh Region: Size, Services, and Alignment with the Saudi Ministry of Health Priorities.

Background: Mapping exercises are important to inform development of interventions aiming to enhance private sector's contribution towards achieving health systems objectives. Objective: To map size, types, and distribution of private health institutions, and to identify the services they offer, and their alignment with Ministry of Health priorities. Methods: A cross-sectional study targeted licensed, for-profit private health institutions in Riyadh Region, Saudi Arabia. Secondary data were collected from Department of Private Health Institutions in Riyadh and the Ministry of Health Year Statistical Book. Descriptive statistics were employed to analyze the collected data. Results: Private hospitals increased from 40 (2017) to 46 (2021), with private sector hospital beds rising from 5,426 (2017) to 6,339 (2021). Pharmaceutical institutions comprised 55.4% of private health institutions, followed by polyclinics (23%) and supportive health services centers (17.1%). Laboratories, hospitals, and clinics represented 2%, 1%, and 0.5% of private health institutions respectively. Ambulance and radiology service centers were least available private health institutions at 0.1%. Home healthcare, remote care, telemedicine, family medicine, and long-term care were offered by 1.3%, 0.5%, 0.4%, and 0.1% of private health institutions respectively. Private hospitals accounted for 41.4% of total hospitals and private hospitals beds constituted 30.9% of Riyadh's total, with an average of 137.8 beds per hospital. Around 82% of private health institutions were in Riyadh city, with around 18% in peripheral provinces. Conclusion: Private healthcare sector has witnessed substantial growth, primarily influenced by supply rather than demand dynamics. Incentives are essential to promote investment in Ministry of Health priorities.

Development of cashew nut shell lignin-acrylonitrile butadiene styrene 3D printed core and industrial hemp/aluminized glass fiber epoxy biocomposite for morphing wing and unmanned aerial vehicle applications.

The aim of this study was to develop a lightweight epoxy based biocomposite for morphing wing and unmanned aerial vehicle (UAV) applications. The proposed composite was developed using a 3D printed high stiffness lignin-Acrylonitrile Butadiene Styrene (ABS) core and industrial hemp with aluminized glass fiber epoxy skin. The ABS was reinforced using lignin macromolecule derived from cashew nut shells via twin screw extruder and the core was printed using an industrial grade 3D printer. Furthermore, the composites were prepared by compression moulding with an ABS-lignin core and hemp/aluminized GF surface and characterized according to respective American society of testing and materials (ASTM) standards. The findings indicate that the addition of 30 vol% Al-glass and hemp fiber with lignin strengthened ABS core improved the mechanical properties. The composite material designated as "E2" exhibits the maximum mechanical properties, providing tensile strength, flexural strength, Izod impact, interlaminar shear strength (ILSS), and compression values of, 136 MPa, 168 MPa, 4.82 kJ/m2, 21 MPa, and 155 MPa respectively. The maximal energy absorbed by composite designation "E2," during drop load impact test is 20.6 J. Similarly, the composite designation "E2"gives fatigue life cycles of 33,709, 25,781 and 19,633 for 50 %, 70 % and 90 % of ultimate tensile strength (UTS) and 32.5 (K1c) MPa⋅m and 0.76 (G1c) MJ/m2 in fracture toughness and energy release rate respectively.

Effect of Number of Tests on the Mechanical Characteristics of Agave sisalana Yarns for Composites Structures: Statistical Approach.

A designer of sustainable biocomposite structures and natural ropes needs to have a high confidence interval (95% CI) for mechanical characteristics data of performance materials, yet qualities for plant-based fibers are very diverse. A comprehensive study of the elements that enhance the performance of biocomposites or sustainable ropes created from vegetable fibers is necessary. The current study included five groups with varying numbers (N) of tests of 20, 40, 60, 80, and 100 on the mechanical characteristics at room temperatures. The purpose of this study was to determine how changing N affects the mechanical properties of sisal yarn. These properties include its strength, Young's modulus, and deformation at rupture. A significance testing program including more than 100 tests was performed. Owing to the heterogeneity of the plant yarn, each group received more than 20 samples at a gauge length (GL) of 100 mm. The tensile strength characteristics of sisal yarns produced a wide range of findings, as is common for natural fibers, necessitating a statistical analysis. Its dispersion was explored and measured using the statistical methods. The Weibull distribution with two parameters and a prediction model with a 95% confidence level for maximum likelihood (ML) and least squares (LS) were used to investigate and quantify its dispersion.

Effect of Fiber Loading on Thermal Properties of Cellulosic Washingtonia Reinforced HDPE Biocomposites.

In this research work, we aim to study the effect of the incorporation of vegetable fiber reinforcement on the thermo-mechanical and dynamic properties of a composite formed by a polymeric matrix reinforced with cellulosic fibers with the various Washingtonia fiber (WF) loadings (0%, 10%, 20%, and 30% by wt%) as reinforced material in high-density polyethylene (HDPE) Biocomposites to evaluate the optimum fiber loading of biocomposites. In addition, several characterization techniques (i.e., thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal mechanical analysis (TMA)) were used to better understand the characteristics of the new composites prepared. With these techniques, we managed to verify the rigidity and thermal stability of the composites so elaborated, as well as the success of the polymer and the structural homogeneity of the obtained biocomposites. Hence, the biocomposite with the best ratio (HDPE/20WF) showed a loss modulus (E″) of 224 MPa, a storage modulus (E') of 2079 MPa, and a damping factor (Tanδ) of 0.270 to the glass transition (Tg) of 145 °C. In addition, thermomechanical analysis (TMA) of the biocomposite samples exhibited marginally higher Ts compared to the HDPE matrix. The best results were recorded with biocomposites with 20% WF, which showed better thermal properties. This composite material can be used as insulation in construction materials (buildings, false ceilings, walls, etc.).

Enhanced Open-Hole Strength and Toughness of Sandwich Carbon-Kevlar Woven Composite Laminates.

Fiber-reinforced plastic composites are sensitive to holes, as they cut the main load-carrying member in the composite (fibers) and they induce out-of-plane stresses. In this study, we demonstrated notch sensitivity enhancement in a hybrid carbon/epoxy (CFRP) composite with a Kevlar core sandwich compared to monotonic CFRP and Kevlar composites. Open-hole tensile samples were cut using waterjet cutting at different width to diameter ratios and tested under tensile loading. We performed an open-hole tension (OHT) test to characterize the notch sensitivity of the composites via the comparison of the open-hole tensile strength and strain as well as the damage propagation (as monitored via CT scan). The results showed that hybrid laminate has lower notch sensitivity than CFRP and KFRP laminates because the strength reduction rate with hole size was lower. Moreover, this laminate showed no reduction in the failure strain by increasing the hole size up to 12 mm. At w/d = 6, the lowest drop in strength showed by the hybrid laminate was 65.4%, followed by the CFRP and KFRP laminates with 63.5% and 56.1%, respectively. For the specific strength, the hybrid laminate showed a 7% and 9% higher value as compared with CFRP and KFRP laminates, respectively. The enhancement in notch sensitivity was due to its progressive damage mode, which was initiated via delamination at the Kevlar-carbon interface, followed by matrix cracking and fiber breakage in the core layers. Finally, matrix cracking and fiber breakage occurred in the CFRP face sheet layers. The specific strength (normalized strength and strain to density) and strain were larger for the hybrid than the CFRP and KFRP laminates due to the lower density of Kevlar fibers and the progressive damage modes which delayed the final failure of the hybrid composite.

Mechanical, thermal, viscoelastic and hydrophobicity behavior of complex grape stalk lignin and bamboo fiber reinforced polyester composite.

This work aims to investigate the degradation stability of bamboo fiber-reinforced polyester composite toughened with complex lignin biopolymer derived from the waste grape stalks. The properties like mechanical, wear, thermal, DMA, and hydrophobic were studied after the addition of lignin and analyzed how the lignin addition influenced these properties. Prior to composite making the fiber and lignin was treated with silane. According to the results obtained incorporating 40 vol% of bamboo fiber into the polyester resin, the mechanical and wear properties enhanced. Further, the composite containing 2.0 vol% of lignin has maximum tensile strength, tensile modulus, flexural strength, flexural modulus, and ILSS. Similarly, the composite designation having 4 vol% lignin revealed the improved wear loss stability of 0.007 mm3/Nm (sp. wear rate). The highest degradation temperature reported for composite designation UBL4 it was 520 °C, with a relatively lesser weight loss of 19 %. Likewise, the highest storage modulus was about 4.5 GPa, and the lowest loss factor was up to 0.3 for the composite designation UBL4. The contact angle investigation revealed that all composite designations are not fall below 70°, indicating their hydrophobic stability. These composites with enhanced stability against load, heat and water could be utilized in the industrial, automotive and defense sectors where high performance outcomes are required.

In vitro biodegradation, cytotoxicity, and biocompatibility of polylactic acid/napier cellulose nanofiber scaffold composites.

This study aimed to evaluate the bioactivities and biocompatibilities of porous polylactic acid (PLA) reinforced with cellulose nanofiber (CNF) scaffolds. The in vitro degradation behaviors of the porous PLA/CNF scaffolds were systematically measured for up to 8 weeks in a phosphate-buffered saline medium at 37 °C. The reinforcement of CNF resisted the biodegradation of the scaffolds. The in vitro cytotoxicity and biocompatibility of the scaffolds were determined using the Beas2B American Type Culture Collection cells. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity and proliferation tests showed that the scaffolds were non-toxic, and epithelial cells grew well on the scaffold after 7 days of culture, whereas the percentage of cell proliferation on the PLA/CNF15 scaffold was the largest, 130 %. A scratch wound-healing assay was performed to evaluate the suitability of the scaffolds for cell migration. The results demonstrated that the scaffolds exhibited good cell migration towards nearly complete wound closure.

Development of Hybrid Composite Utilizing Micro-Cellulose Fibers Extracted from Date Palm Rachis in the Najran Region.

Environmental effects can be reduced by using renewable resources in various applications. The date palm fibers (DPF) used in this study were extracted from waste date ranches of the Najran region by retting and manual peeling processes. The biocomposites were developed by reinforcing the silane-treated DPF (SDPF) at different wt.% in eugenol phthalonitrile (EPN) and difunctional benzoxazine (BA-a) copolymer. The impact strength, tensile, flexural, and dynamic mechanical properties and thermogravimetric analysis were evaluated to understand the mechanical, thermomechanical, and thermal properties. Results confirmed that 30 wt.% SDPF-reinforced poly (EPN/BA-a) composites produced the highest mechanical and thermomechanical properties, and were considered optimized SDPF reinforcement. Furthermore, hybrid composites with 30 wt.% SDPF and 15 wt.% silane-treated glass fibers (SGF) reinforcement having different lamination sequences were also studied. The lamination sequences showed a significant impact on the mechanical and thermomechanical properties, as properties were further enhanced by adding a core layer of SGF in hybrid composites. However, the thermal properties of SDPF/SGF laminates were higher than SDPF biocomposites, but the SGF lamination sequence did not produce any impact. According to the limiting oxygen and heat resistance indexes, the developed SDPF/SGF laminates are self-extinguishing materials and can be used in temperature-tolerant applications up to 230 °C.

Study on Flexural Behavior of Glass Fiber Reinforced Plastic Sandwich Composites Using Liquid Thermoplastic Resin.

Experimental and numerical studies of composite sandwich structures are warranted to reap the benefits of these materials when they are well designed. In the current research, new liquid thermoplastic and epoxy resins were used to fabricate four composite sandwich panels with two additional foam types and different densities in the wind turbine industry. A comprehensive comparison of three-point bending test results was made. Finite-element-based simulations using the ABAQUS program with Hashin's damage criterion were conducted to examine the failure behavior of the GFRP sandwich composites. The flexural behavior of the glass-fiber-reinforced plastic (GFRP) sandwich panels was investigated and compared with the experiments. The results show that the GF/PVC/Elium composite panel gives the highest load absorption, flexural strength, flexural modulus, core shear ultimate strength, and facing stress due to effect of the core foam and resin types. For the PVC foam core sandwich panel, using thermoplastic resin increased the flexural strength by 18% compared to that of the epoxy resin. The simulation results show excellent agreement between the finite-element-predicted failure loads and the experimental results.

Effects of Ply Orientations and Stacking Sequences on Impact Response of Pineapple Leaf Fibre (PALF)/Carbon Hybrid Laminate Composites.

This study investigated the impact response behaviours of pineapple leaf fibre (PALF)/carbon hybrid laminate composites for different ply orientations and stacking sequences. The laminates were manufactured using a vacuum infusion approach with various stacking sequences and ply orientations classified as symmetric quasi-isotropic, angle-ply symmetric, and cross-ply symmetric. The laminates were analysed using an IMATEK IM10 drop weight impact tester with an increment of 5 J until the samples were perforated. This investigation reveals that the overall impact properties of PALF and carbon as reinforcements were improved by a beneficial hybridised effect. The laminates with an exterior carbon layer can withstand high impact energy levels up to 27.5 J. The laminate with different stacking sequences had a lower energy transfer rate and ruptured at higher impact energy. The laminates with ply orientations of [0°/90°] and [±45°]8 exhibited 10% to 30% better energy absorption than those with ply orientations of [±45°2, 0°/90°2]s and [0°/90°2, ±45°2]s due to energy being readily transferred within the same linear ply orientation. Through visual inspection, delamination was observed to occur at the interfaces of different stacking sequences and ply orientations.

Effect of Embedded Thin-Plies on the Charpy Impact Properties of CFRP Composites.

In this study, different configurations of epoxy composite laminates that contained thin plies were prepared and characterised for sudden impact load bearing applications. The primary aim of this investigation was to develop a hybrid epoxy-based thin ply composite for aerospace and automotive applications that would be tolerant of high impacts. The impact properties of the selected configurations were investigated both experimentally and numerically under low-velocity Charpy impact loading conditions. Furthermore, any damage to the laminates was evaluated with an emphasis on the identification of dominant damage mechanisms and locations. This included a comparison between the laminates that were made from traditional plies and the thin ply laminates in terms of their absorbed energy and failure modes. The results revealed that the integration of thin plies into normal ply had a major effect on the amount of absorbed energy under flatwise conditions: up to 8.7 J at a cut-off angle of 90°. However, edgewise conditions produced a maximum observed energy of 10.0 J for the thin plies that were surrounded by normal plies (Plate 3). The damage assessments showed the increased damage resistance of the hybrid thin ply composites due to their uniform stress distribution. The traditional ply composites incurred large deformations from the impact loads. Moreover, it was noted that delamination formed in the middle regions of the traditional plies. The FEM model analysis revealed that it was capable of accurately predicting the absorbed energy for different configurations of composites, which were prepared and analysed experimentally. Both the experimental and numerical values were very similar to each other. These impact damage assessments improved the thin ply composites so that they could be used as working materials for applications that are prone to high loads, such as the aerospace, defence, automotive and structural industries.

Bearing Properties of CFRP Composite Laminates Containing Spread-Tow Thin-Plies.

With the development of spread-tow, thin-ply technology, ultra-thin composite laminates could be produced. Composite bolted joints are commonly used on aircraft's load-bearing structures and are considered the main cause of stress concentration. The aim of this research is to investigate the bolted joint behavior of composite laminates that combine thin-plies and conventional thick-plies in a predetermined stacking sequence. The impact of thin-ply placement within the stack on bearing strength, including the onset of damages, is examined. The work involves mechanical tests and fractographic activities to understand the damage mechanisms of the plies and their interactions, and its reflections on the bearing load capacity of the joint for double-lap bolted joints. The results showed an improvement in the bearing strength of up to 19% by inserting the thin-plies inside the laminate. The visual examination of the specimens showed a bearing damage mode for all the tested specimens. The computed tomography scans showed damage mechanisms that mostly occurred with the normal plies, rather than breaking the thin-plies. For the specimens of traditional plies, delaminations were noticed at most of the interfaces. For the one with a block of thin-plies in the middle, all the delaminations were forced to the surface layers with an extra large size. Forspecimens with distributed thin-plies, a higher number of smaller delaminations was recognized.

Physical, Thermal Transport, and Compressive Properties of Epoxy Composite Filled with Graphitic- and Ceramic-Based Thermally Conductive Nanofillers.

Epoxy polymer composites embedded with thermally conductive nanofillers play an important role in the thermal management of polymer microelectronic packages, since they can provide thermal conduction properties with electrically insulating properties. An epoxy composite system filled with graphitic-based fillers; multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs) and ceramic-based filler; silicon carbide nanoparticles (SiCs) was investigated as a form of thermal-effective reinforcement for epoxy matrices. The epoxy composites were fabricated using a simple fabrication method, which included ultrasonication and planetary centrifugal mixing. The effect of graphite-based and ceramic-based fillers on the thermal conductivity was measured by the transient plane source method, while the glass transition temperature of the fully cured samples was studied by differential scanning calorimetry. Thermal gravimetric analysis was adopted to study the thermal stability of the samples, and the compressive properties of different filler loadings (1-5 vol.%) were also discussed. The glass temperatures and thermal stabilities of the epoxy system were increased when incorporated with the graphite- and ceramic-based fillers. These results can be correlated with the thermal conductivity of the samples, which was found to increase with the increase in the filler loadings, except for the epoxy/SiCs composites. The thermal conductivity of the composites increased to 0.4 W/mK with 5 vol.% of MWCNTs, which is a 100% improvement over pure epoxy. The GNPs, SiCs, and MWCNTs showed uniform dispersion in the epoxy matrix and well-established thermally conductive pathways.

Effect of Fibre Surface Treatment and Nanofiller Addition on the Mechanical Properties of Flax/PLA Fibre Reinforced Epoxy Hybrid Nanocomposite.

Natural fibre-based materials are gaining popularity in the composites industry, particularly for automotive structural and semi-structural applications, considering the growing interest and awareness towards sustainable product design. Surface treatment and nanofiller addition have become one of the most important aspects of improving natural fibre reinforced polymer composite performance. The novelty of this work is to examine the combined effect of fibre surface treatment with Alumina (Al2O3) and Magnesia (MgO) nanofillers on the mechanical (tensile, flexural, and impact) behaviour of biotex flax/PLA fibre reinforced epoxy hybrid nanocomposites. Al2O3 and MgO with a particle size of 50 nm were added in various weight proportions to the epoxy and flax/PLA fibre, and the composite laminates were formed using the vacuum bagging technique. The surface treatment of one set of fibres with a 5% NaOH solution was investigated for its effect on mechanical performance. The results indicate that the surface-treated reinforcement showed superior tensile, flexural, and impact properties compared to the untreated reinforcement. The addition of 3 wt. % nanofiller resulted in the best mechanical properties. SEM morphological images demonstrate various defects, including interfacial behaviour, fibre breakage, fibre pullout, voids, cracks, and agglomeration.

Enhancing Impact Energy Absorption, Flexural and Crash Performance Properties of Automotive Composite Laminates by Adjusting the Stacking Sequences Layup.

In response to the high demand for light automotive, manufacturers are showing a vital interest in replacing heavy metallic components with composite materials that exhibit unparalleled strength-to-weight ratios and excellent properties. Unidirectional carbon/epoxy prepreg was suitable for automotive applications such as the front part of the vehicle (hood) due to its excellent crash performance. In this study, UD carbon/epoxy prepreg with 70% and 30% volume fraction of reinforcement and resin, respectively, was used to fabricate the composite laminates. The responses of different three stacking sequences of automotive composite laminates to low-velocity impact damage and flexural and crash performance properties were investigated. Three-point bending and drop-weight impact tests were carried out to determine the flexural modulus, strength, and impact damage behavior of selected materials. Optical microscopy analysis was used to identify the failure modes in the composites. Scanning electron microscopy (SEM) and C-scan non-destructive methods were utilized to explore the fractures in the composites after impact tests. Moreover, the performance index and absorbed energy of the tested structures were studied. The results showed that the flexural strength and modulus of automotive composite laminates strongly depended on the stacking sequence. The highest crash resistance was noticed in the laminate with a stacking sequence of [[0, 90, 45, -45]2, 0, 90]S. Therefore, the fabrication of a composite laminate structure enhanced by selected stacking sequences is an excellent way to improve the crash performance properties of automotive composite structures.

Prevalence and mortality due to acute kidney injuries in patients with influenza A (H1N1) viral infection: A systemic narrative review.

INTRODUCTION: There is limited evidence of studying the associated factors of acute kidney injury (AKI) among patients with influenza A (H1N1) virus infection pandemic in 2009. AKI is one of the most prevalent complications in the intensive care unit. Its incidence is associated with high mortality and negative impacts on long-term survival. The aim of this narrative review was to determine the prevalence and mortality due to AKI, among patients admitted with the H1N1 virus. MATERIALS AND METHODS: A narrative review of studies reporting about treatment measures and mortality associated with AKI during the H1N1 pandemic over a 10-year period (from September 2009 to August 2018), was performed. We searched the following databases; EMBASE, Medline/PubMed, NHS evidence, Google Scholar, and the Cochrane Library. Our inclusion revealed 20 studies of patients (n = 3579) who were admitted with H1N1 infection and developed AKI. RESULTS: In this study, 33% of patients (n = 1164) who were admitted with H1N1 infection had developed AKI. Within the first 5 years (2009 to 2013), 36% of patients (n = 1013) developed AKI. Within the next 5 years (2014-2018), 812 patients were admitted with the H1N1 infection and 18% of patients (n = 150) had developed AKI. Over the 10 years, there was a 50% reduction in the number of patients who developed AKI (2009 and 2018) (P < 0.0001). CONCLUSION: Patients showed varied responses to treatment measures, depending on their geographical location, comorbidities, and other characteristics. Despite a reasonable prevalence of AKI among patients with the H1N1 virus infection, the mortality over the last 10 years was reduced, with renal replacement therapy as a common therapy in most studies.

Female gender doubles pre-hospital delay times for patients experiencing ST segment elevation myocardial infarction in Saudi Arabia.

INTRODUCTION: Pre-hospital delay has a significant impact on patients' mortality and morbidity in ST segment elevation myocardial infarction (STEMI). Internationally many factors including female gender have been implicated, but no research has been conducted in Arab cultures. We aimed to explore the factors contributing to pre-hospital delay among female STEMI patients in Saudi Arabia. METHOD: This sequential, explanatory mixed methods study comprised a consecutive sample of 311 patients, presenting with STEMI to three hospitals in Riyadh, from March 2011-August 2011. Of these, 189 patients (36 females) were eligible and interviewed using the Response to Symptoms Questionnaire. A purposive sample of 18 patients (9 females) then participated in qualitative interviews that were taped and transcribed prior to thematic analysis. FINDINGS: The median pre-hospital delay for males was 5 h and 12.9 h for females (p<0.002). Standard multiple regression determined female gender as the strongest predictor of transfer delay-from decision to seek help to hospital arrival. Qualitative analysis produced five gender-related themes: (a) women require a male relative's permission to seek medical help; (b) women cannot travel to hospital unless accompanied by a male relative; (c) women prioritise family responsibilities over seeking help; (d) women lack knowledge of myocardial infarction (MI) symptoms and treatment; and (e) perception that women should not attract attention. CONCLUSION: This study provides new insight into how cultural factors increase pre-hospital delay for women within Saudi Arabia. While the quantitative data demonstrates that women experience much longer delays, the qualitative interviews confirm that cultural factors are implicated. Further research is urgently required.