ABSTRACT
This paper reports a nonbraided, bioresorbable polycaprolactone (PCL) flow diverter (FD) for the endovascular treatment of aneurysms. Bioresorbable FDs can reduce the risk associated with the permanent metallic FDs as they are resorbed by the body after curing of aneurysms. PCL FDs were designed and fabricated using an in-house hybrid electromelt spinning-fused deposition fabrication unit. Flow diverter's properties, surface qualities, and mechanical characteristics of PCL FDs of 50%, 60%, and 70% porosities were studied using scanning electron microscope (SEM), atomic force microscopy (AFM), and high precision universal testing machine (UTM). The deployability through a clinically relevant catheter was demonstrated in a PDMS aneurysm model. The angiographic visibility of the developed PCL FDs was evaluated using BaSO4 and Bi2O3 coatings of various concentration. The average strut thicknesses were 74.12 ± 6.63 µm, 63.07 ± 1.26 µm, and 56.82 ± 2.09 µm for PCL FDs with 50%, 60%, and 70% porosities, respectively. They average pore areas for the 50%, 60% and 70% porosities FDs were 0.055 ± 0.0056 mm2, 0. 0605 ± 0.0065 mm2, and 0.0712 ± 0.012 mm2, respectively. The surface quality was great with an RMS roughness value of 14.45 nm. The tensile, radial strength, and flexibility were found to be satisfactory and comparable to the nonbraided coronary stents. The developed PCL FDs were highly flexible and demonstrated to be deployable through conventional delivery system as low as 4 Fr catheters in a PDMS aneurysm model. The visibility under X-ray increases with the increasing concentration of coating materials BaSO4 and Bi2O3. The visibility intensity was slightly higher with Bi2O3 coating of PCL FDs. The overall results of the engineering analysis of the developed nonbraided PCL FDs are promising.
Subject(s)
Endovascular Procedures , Intracranial Aneurysm , Humans , Absorbable Implants , Stents , Endovascular Procedures/methodsABSTRACT
A negative effective mass can be realized in quantum systems by engineering the dispersion relation. A powerful method is provided by spin-orbit coupling, which is currently at the center of intense research efforts. Here we measure an expanding spin-orbit coupled Bose-Einstein condensate whose dispersion features a region of negative effective mass. We observe a range of dynamical phenomena, including the breaking of parity and of Galilean covariance, dynamical instabilities, and self-trapping. The experimental findings are reproduced by a single-band Gross-Pitaevskii simulation, demonstrating that the emerging features-shock waves, soliton trains, self-trapping, etc.-originate from a modified dispersion. Our work also sheds new light on related phenomena in optical lattices, where the underlying periodic structure often complicates their interpretation.
ABSTRACT
Titanium (Ti) alloys have been widely used in orthopedics and orthodontic surgeries as implants because of their beneficial chemical, mechanical, and biological properties. Improvement of these properties of a Ti alloy, Ti-6Al-4V Eli, is possible by the use of plasma nitriding treatment on the Ti alloy. The novelty of this study is the evaluation of a DC glow discharge nitrogen plasma treatment method on the surface, mechanical and biological properties of Ti alloy. Specifically, this study measured the chemical states, roughness, hardness, and biocompatibility of plasma nitride treated Ti-6Al-4V Eli as well as determined the effect of plasma treatment on the fracture strength between the Ti alloy and bone clement. This study hypothesized that DC glow discharge nitrogen plasma treatment may alter the surface chemical and mechanical states of the Ti alloy that may influence the fracture strength of implant/cement interfaces under static load. This study found that plasma nitride treatment on Ti alloy does not have effect on the roughness and biocompatibility (P value > 0.5), but significantly effect on the hardness and fracture strength of Ti-bone cement interfaces compared to those values of untreated Ti samples (P value < 0.5). Therefore, the DC glow discharge nitrogen plasma treated Ti alloy can potentially be used for orthopedic applications.
Subject(s)
Biocompatible Materials/chemistry , Bone Cements/chemistry , Dental Alloys/chemistry , Plasma Gases/chemistry , Titanium/chemistry , Animals , Cell Adhesion , Cell Line , Hardness , Materials Testing , Mice , Osteoblasts/cytology , Surface Properties , Tensile StrengthABSTRACT
In the present study the in vitro antimicrobial activity, along with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), of different extracts of leaves of Mussaenda roxburghii Hook. f. were evaluated against 13 pathogenic microorganisms. The methanol extract and its carbon tetrachloride and chloroform soluble fractions showed the highest antimicrobial activity. The chloroform soluble fraction showed the maximum inhibition zone of 16.0 mm against Bacillus megaterium with MIC and MBC values of 7.81 ug/ml and 250 ug/ml, respectively. Ciprofloxacin (30 ug/disc) was used as standard antimicrobial agent. In the brine shrimp lethality bioassay, both the petroleum-ether and carbon tetrachloride soluble fraction of crude methanol extract demonstrated strong cytotoxic activity with LC50 value of 0.52 and 0.62 ug/ml, respectively compared to that of 0.451 ug/ml exhibited by standard vincristine sulfate.
En el presente estudio, la actividad antimicrobiana in vitro, junto con la concentración inhibitoria mínima (CIM) y la concentración bactericida mínima (CBM), de diferentes extractos de las hojas de Mussaenda roxburghii Hook. f. fueron evaluadas contra 13 microorganismos patógenos. El extracto metanólico y sus fracciones solubles en tetracloruro de carbono y cloroformo mostraron la actividad antimicrobiana más alta. La fracción soluble en cloroformo mostró la zona de inhibición máxima de 16,0 mm en contra de Bacillus megaterium, con valores de MIC y CBM de 7,81 g/ml y 250 mg/ml, respectivamente. Ciprofloxacina (30 ug/disco) se usó como agente antimicrobiano estándar. En el bioensayo de letalidad con Artemia salina, tanto el petróleo-éter y tetracloruro de carbono como la fracción soluble del extracto de metanol crudo demostraron una fuerte actividad citotóxica con valores de LC50 de 0,52 y 0,62 mg/ml, respectivamente, en comparación con la de 0,451 mg/ml de sulfato de vincristina utilizado como estándar.
