Additive manufacturing of strong silica sand structures enabled by polyethyleneimine binder

Binder Jet Additive Manufacturing (BJAM) is a versatile AM technique that can form parts from a variety of powdered materials including metals, ceramics, and polymers. BJAM utilizes inkjet printing to selectively bind these powder particles together to form complex geometries. Adoption of BJAM has been limited due to its inability to form strong green parts using conventional binders. We report the discovery of a versatile polyethyleneimine (PEI) binder for silica sand that doubled the flexural strength of parts to 6.28 MPa compared with that of the conventional binder, making it stronger than unreinforced concrete (~4.5 MPa) in flexural loading. Furthermore, we demonstrate that PEI in the printed parts can be reacted with ethyl cyanoacrylate through a secondary infiltration, resulting in an increase in flexural strength to 52.7 MPa. The strong printed parts coupled with the ability for sacrificial washout presents potential to revolutionize AM in various applications including construction and tooling.

Aplicación de 2 etil-cianoacrilato para sutura de heridas faciales

La sutura de heridas faciales siempre ha sido un tema controversial, en especial sobre la estética que deja este tipo de procedimiento, ya que el éxito o el fracaso de este depende de varios factores, dentro de ellos podemos referirnos a: el operador, la técnica o el material que se usa para hacer la síntesis de la herida. Lo anterior anuncia la necesidad de un estudio multidisciplinario, en el que los investigadores evalúen alternativas para suturar las heridas. La investigación que se reporta en este artículo es un diseño de serie de casos, desarrollado con seis pacientes pediátricos con heridas faciales a quienes se les aplicó 2 etil-cianoacrilato una fórmula química de C6H7NO2, que fueron apoyados con antibioticoterapia y analgésico dependiendo el caso; se realizaron una serie de evaluaciones periódicas a los casos (1 día, 3 días, 7 días, 14 días y 30 días). El estudio concluyó que la mayoría de los pacientes tuvo una evolución satisfactoria, todos los casos presentaron dolor según la escala EVA en 2 y 3. Por ende, este estudio aporta que el 2 etil-cianoacrilato es una alternativa para las suturas de heridas pediátricas sin ningún efecto adverso. Palabras clave: 2-etil-cianoacrilato, heridas faciales, pacientes pediátricos, cirugía estética, Cirugía Bucal y Maxilo Facial. Abstract The suture of facial wounds has always been a controversial topic, especially regarding the aesthetics that this type of procedure leaves behind. Since, the success or failure of this depends on several factors, within them we can refer to the operator, the technique, or the material that is used to make the synthesis of the wound. The foregoing, heralds the need for a multidisciplinary study, in which researchers evaluate alternatives to suture wounds. The research reported in this article is a case series design, developed with six pediatric patients with facial wounds to whom 2 ethyl-cyanoacrylate was applied, chemical formula of C6H7NO2, which were supported with antibiotic therapy and analgesic as appropriate; A series of periodic evaluations were carried out on the cases (1 day, 3 days, 7 days, 14 days and 30 days). The study concluded that most patients had a satisfactory evolution, all cases presented pain according to the VAS scale in 2 and 3. Therefore, this study contributes that 2 ethyl-cyanoacrylate is an alternative for wound sutures pediatric without any adverse effect. Keywords: 2-ethyl-cyanoacrylate, facial wounds, pediatric patients, plastic surgery, oral surgery y Maxillo facial.

Short-chain cyanoacrylates and long-chain cyanoacrylates (Dermabond) have different antimicrobial effects

ObjectiveTo compare the antimicrobial effect in vitro of a short-chain cyanoacrylate with a long-chain cyanoacrylate (Dermabond, Ethicon, Johnson and Johnson, USA) against bacterial strains.Methods and analysisThe following bacterial strains were analysed: Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. For each microorganism, standardised sterile discs (6 mm) containing 10 µL of ethyl-cyanoacrylate and 2-octyl cyanoacrylate were applied to the plate. All plates received a blank filter-paper disc with no adhesive (control). All plates were incubated for 24 hours, after which the bacterial inhibitory halos, if present, were measured in millimetres in its greater length.ResultsInhibitory halos were observed for both adhesives for S. aureus. Inhibition halos were observed only for ethyl-cyanoacrylate for K. pneumoniae and E. coli. No inhibition halo was observed for P. aeruginosa in any sample. The relationship between the total size of the inhibition halos and the diameter of the paper filter for S. aureus was statistically significant compared with 2-octyl cyanoacrylate.ConclusionData shown conclude that ethyl-cyanoacrylate showed in vitro bacteriostatic activity for S. aureus, E. coli and K. pneumoniae. 2-Octyl cyanoacrylate showed in vitro lower bacteriostatic activity only against S. aureus when compared with ethyl-cyanoacrylate. No in vitro bactericidal activity of ethyl-cyanoacrylate or 2-octyl cyanoacrylate was observed.

Ethyl cyanoacrylate reinforced polyvinylidene fluoride separators for robust lithium ion batteries

Ideal separators of Li-ion batteries should own key characteristics simultaneously, including high mechanical strength, high thermal stability and high electrolyte wettability. Herein a composite separator is proposed to realize these...