Enhancing the mechanical properties of CF-reinforced epoxy composites through chemically surface modification of carbon fibers via novel two-step approach by addition of epichlorohydrin

The chemical surface modification was carried out in this study to improve the interface connection between carbon fiber and epoxy matrix to study the mechanical and fracture behavior of CF-reinforced epoxy composites. Finite element analysis was carried out by using ABAQUS software to simulate the variation of the tensile strength (TS), interfacial shear strength (IFSS), and interlaminar shear strength (ILSS). The chemical surface modification was carried out by the chemical oxidation by nitric acid and subsequently, addition of monomer resin of epichlorohydrin in a solution at 80 °C. The Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), and Scanning Electron microscopy (SEM) were carried out to ensure the successful surface modification of CFs. Subsequently, surface-modified CF-reinforced epoxy composites were prepared through the hand lay-up method with the volume fraction of 20 wt.%, and curing was carried out at 80 °C for 4 h. The TS, IFSS, and ILSS values equaled 462.82 MPa, 156 MPa, and 4.1 MPa for modified CF/epoxy composites were achieved, respectively, which are improved remarkably compared to unmodified ones (380, 81, and 2.9 MPa). These improvements are attributed to the successful surface modification of CFs by epichlorohydrin. The surface modification causes the increase in wettability of CFs and the formation of mechanical interlocking and interaction between CFs and epoxy matrix was achieved through uniform and homogenous distribution of epichlorohydrin on the surface of CFs. Fractography was carried out, which indicated the sound and uniform adhesion between CF and epoxy matrix. Achieved results are consistent with simulated results

Dissolution rate enhancement of ketoconazole by liquisolid technique

The study was conducted to enhance the dissolution rate of ketoconazole (KCZ) (a poorly water-soluble drug) using the liquisolid technique. Microcrystalline cellulose, colloidal silica, PEG400 and polyvinyl pyrrolidone (PVP) were employed as a carrier, coating substance, nonvolatile solvent and additive in the KCZ liquisolid compact formulation, respectively. The drug-to-PEG400 and carrier-to-coating ratio variations, PVP concentration and aging effects on the in vitro release behavior were assessed. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) data revealed no alterations in the crystalline form of the drug and the KCZ-excipient interactions within the process. The load factor and the drug release rate were significantly enhanced compared to directly compressed tablets in the presence of the additive. Increasing the PEG400-to-drug ratio in liquid medications enhanced the dissolution rate remarkably. The dissolution profile and hardness of liquisolid compacts were not significantly altered by keeping the tablets at 40 °C and relative humidity of 75 % for 6 months. With the proposed modification of the liquisolid process, it is possible to obtain flowable, compactible liquisolid powders of high-dose poorly-water soluble drugs with an enhanced dissolution rate

Microfluidic manufacture of lipid-based nanomedicines

Nanoparticulate technologies have revolutionised drug delivery allowing for passive and active targeting, altered biodistribution, control drug release (temporospatial or triggered), enhanced sta-bility, improved solubilisation capacity, reduction of dose and adverse effects. However, their manufacture remains immature, and challenges exist in industrial scale due to high batch-to-batch variability hindering their clinical translation. Lipid-based nanomedicines remain the most-widely approved nanomedicines and their current manufacturing methods remain discontinuous and face several problems such as high batch-to-batch variability affecting the critical quality attributes (CQAs) of the product, laborious multi-step processes, need for an expert workforce and are not easily amenable to industrial scale-up involving typically a complex process control. Several tech-niques have emerged in recent years for nanomedicine manufacture, but a paradigm shift occurred when microfluidic strategies able to mix fluids in channels with dimensions of tens of micrometers and small volumes of liquid reagents in a highly controlled manner to form nanoparticles with tunable and reproducible structure are employed. In this review, we summarize the recent ad-vancements in the manufacturing of lipid-based nanomedicines using microfluidics with particular emphasis on the parameters that govern the control of CQAs of final nanomedicines. The impact of microfluidic environments on formation dynamics of nanomaterials, and the application of mi-crodevices as platforms for nanomaterial screening were also discussed

Stimuli-responsive synthesis of silver nanoparticles applying green and chemical reduction approaches

Introduction: The current study reports the comparative stimuli-responsive synthesis of silver nanoparticles (AgNPs) with various sizes and morphologies employing Lycium ruthenicum (L. ruthenicum) extract and sodium citrate solutions. Methods: The morphology and size of AgNPs were regulated by varying the pH values, concentrations of the extract solution, and temperatures in the reaction medium. The prepared AgNPs were assessed via various instrumental analyses, including UV-Vis, FTIR, XRD, TEM, and DLS. Results: The L. ruthenicum extract displayed several functional groups that reduced the Ag ions to the AgNPs at different values of pH. However, the primary chemical structure of L. ruthenicum was virtually unaltered at these conditions. Variations in the pH and extract concentration of the reaction medium yielded AgNPs of different sizes and morphologies. Both bio- and chemo-synthesized AgNPs revealed a relatively dispersed sphere-shaped morphology under alkaline conditions (≈ 36 nm). Conclusion: This study introduced a simple, valuable, and green technique for stimuli-sensitive AgNPs synthesis employing the L. ruthenicum extract

Multiple dental anomalies accompany unilateral disturbances in abducens and facial nerves : a case report

This article describes the oral rehabilitation of an 8-year-old girl with extensively affected primary and permanent dentition. This report is unique in which distinct dental anomalies including enamel hypoplasia, irregular dentin formation, taurodontism, hpodontia and dens in dente accompany unilateral disturbance of abducens and facial nerves which control the lateral eye movement, and facial expression, respectively

Multiple dental anomalies accompany unilateral disturbances in abducens and facial nerves: A case report

This article describes the oral rehabilitation of an 8-year-old girl with extensively affected primary and permanent dentition. This report is unique in which distinct dental anomalies including enamel hypoplasia, irregular dentin formation, taurodontism, hpodontia and dens in dente accompany unilateral disturbance of abducens and facial nerves which control the lateral eye movement, and facial expression, respectively. Keywords: enamel hypoplasia; irregular dentin formation; taurodontism; hypodontia; dens in dente; abducens and facial nerves

Made-on-demand, complex and personalized 3D-printed drug products

Layer-by-layer fabrication of three dimensional (3D) objects from digital models is called 3D printing. This technology established just about three decades ago at the confluence of materials science, chemistry, robotics, and optics researches to ease the fabrication of UV-cured resin prototypes. The 3D technology was rapidly considered as a standard instrument in the aerospace, automotive, and consumer goods production factories. Nowadays, research interests in the 3D printed products have been raised and achieved ever-increasing traction in the pharmaceutical industry; so that, the first 3D printed drug product was approved by FDA in August 2015. This editorial summarizes the competitive advantages of the 3D printing for the made-on-demand, personalized and complex products, manufacturing of which establish opportunities for enhancing the accessibility, effectiveness, and safety of drugs

Nanomedicines for delivery across the blood-brain barrier

Central nervous system (CNS) disorders affect one in three worldwide and represent a large unmet medical need involving chronic conditions such as Alzheimer’s and Parkinson’s disease, stroke, brain tumours, migraine, pain, and mental diseases. CNS drug development is hampered by the restricted drug and biological transport across an anatomical barrier, the blood-brain barrier. Many brain tumours and neurological diseases can greatly benefit from the use of emerging nanotechnologies based on targeted nanomedicines that are able to noninvasively transport highly potent and specific pharmaceuticals across the blood–brain barrier. In this chapter, we will discuss blood-to-brain drug delivery strategies using nanocarriers such as polymeric and lipid-based strategies with a focus on the mechanism of permeation, pharmaceutical, pharmacokinetic/pharmacodynamic and regulatory and clinical aspects of their development. Although it remains unrealistic to expect a magic bullet for brain central nervous system delivery, nanomedicines are the only technologies to date to have shown considerable promise for these patients with chronic and devastating brain diseases

Risk assessment of electrofusion joints in commissioning of polyethylene natural gas networks

The application of polyethylene pipes and equipment in the natural gas networks is continuously increasing due to their competitive weight and cost compared to metallic materials. Electrofusion welding is an effective and fast approach for the production of polyethylene joints with high safety and endurance. However, recently intermittent failures have reported in underground polyethylene piping networks. Although the failure frequencies are low, but disasters could happen due to the failure in gas pipelines as they usually buried in populated areas. In this study a combination of Failure Mode and Effects Analysis (FMEA), and empirical methods were used to identify main damage mechanisms incorporated to intermittent failures of polyethylene natural gas networks. After performing the FMEA process, based on the obtained risk ranking, three most critical damage mechanisms, including improper scraping, lipid contaminations, and humidity existence in weld zones were investigated experimentally to determine their practical severity. According to empirical evaluations, improper scraping was the most severe damage mechanism, followed by the contaminated welding surfaces during the weld construction

Electrosprayed polymeric nanobeads and nanofibers of modafinil : preparation, characterization, and drug release studies

Introduction: Modafinil (MDF) is used orally for the treatment of attention-deficit/hyperactivity disorder and narcolepsy. It holds low solubility and high permeability; therefore, improving its dissolution properties by preparing nanoformulations can be a promising approach to enhance its oral absorption. Our aims were to prepare and characterize MDF-Eudragit® RS100 (MDF-ERS) nanoparticles by electrospray technique. Methods: Electrosprayed nanoparticles were fabricated by varying MDF to ERS ratios and concentrations. The formulations were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier-transform infrared spectroscopy (FTIR). Release studies were performed on nanoparticles, physical mixtures, and raw MDF. The release data were fitted to different models to understand the mechanism of the drug release. Results: Electrospraying of MDF and ERS solution resulted in the preparation of nonobeads or nanofibers, and the particulate characteristics of the obtained products were largely controlled by the polymer amount in the solution. PXRD and thermal analyses showed that MDF was an amorphous phase in the structures of nanoparticles. Using FTIR, no interaction was observed between MDF and ERS in nanoparticles. Nanoparticles showed biphasic release profiles and the order of dissolution rates was: nanofibers>MDF>nanobeads. The well-fitted model was Weibull model, indicating a Fickian diffusion as the main mechanism of release. Conclusion: The results suggest that by optimization of variables such as solution concentration of MDF-ERS nanofibers and nanobeads with higher dissolution rates can be made by electrospray. Electrospray deposition as a simple, continuous, and surfactant free method is an excellent choice for preparation of drug loaded polymeric nanoparticles