Box-Behnken Design a Key Tool to Achieve Optimized PCL/Gelatin Electrospun Mesh

Hybrid electrospun nanofibers of polycaprolactone (PCL)/gelatin are considered as drug-delivery systems for increasing the treatment efficacy in superficial (skin) wounds. Continuous delivery of therapeutic agents, skin extracellular matrix similarity, management of wound exudate, and antimicrobial barrier effect are the major advantages of electrospun nanofibers in skin applications. Additionally, combining the favorable properties of PCL and gelatin, regarding their biocompatibility, biodegradability and mechanical performance have been revealed promising parameters to be considered for blend in hybrid structures. However, the usual optimization protocol of nanofibers’ production in electrospinning is based on the observation of one-variable-at-time being this methodology expensive and time-consuming. Therefore, in this research work, a statistical model based on four input variables namely, the flow rate, the needle-working distance, the applied voltage, and the ratio of PCL in the solution, is developed to predict the behavior of nanofibers. The performance of nanofibers is monitored by measurements of fiber's diameter, mesh's thickness, and mesh's permeability. Overall, the model showed to be statistically significant (p-value < 0.05) and an independent analysis validated the predicted response for optimal condition. Finally, a delivery study is performed to evaluate the electrospun mesh performance as a drug carrier.     

Polymorphism in Gd2Ge2O7 ceramics: Structural,vibrational, and optical features

In this work, Gd₂Ge₂O₇ polymorphs were obtained by solid-state reactions at 1100–1300 °C. Structural and vibrational features were investigated by X-ray diffraction and Raman spectroscopy. For the triclinic (space group P1) polymorph, all the predicted phonons were discerned in perfect agreement with the group theory calculations, while for the tetragonal polymorph (space group P4₁2₁2), 53 bands of the 81 predicted modes could be identified and characterized. The Gd³⁺ 4f-4f electronic transitions were investigated by diffuse reflectance spectroscopy in the range 200–340 nm. By applying the Kubelka-Munk function, it was possible to determine the bandgap values for all ceramics studied. The tetragonal polymorph exhibited higher bandgap values (5.88 eV) than the triclinic one (5.59 eV), which are both more energetic than other pyrochlore polymorphs reported in the literature. The results indicate that the presence of polymorphism in Gd₂Ge₂O₇ ceramics can be used to produce tailor-made materials since their crystal structures have a strong influence on their optical properties. Consequently, these properties could be used to tuning the optical properties of Gd-containing materials to sensitize and transfer energy to other luminescent lanthanide ions, aiming for innovative applications.     

Two-step sinter-crystallization of K2O–CaO–P2O5–SiO2 (45S5-K) bioactive glass

Bioactive glasses and glass-ceramics (GCs) effectively regenerate bone tissue, however most GCs show improved mechanical properties. In this work, we developed and tested a rarely studied bioactive glass composition (24.4K₂O-26.9CaO-46.1SiO₂-2.6P₂O₅ mol%, identified as 45S5-K) with different particle sizes and heating rates to obtain a sintered GC that combines good fracture strength, low elastic modulus, and bioactivity. We analyzed the influence of the sintering processing conditions in the elastic modulus, Vickers microhardness, density, and crystal phase formation in the GC. The best GC shows improved properties compared with its parent glass. This glass achieves a good densification degree with a two-step viscous flow sintering approach and the resulting GC shows as high bioactivity as that of the standard 45S5 Bioglass®. Furthermore, the GC elastic modulus (56 GPa) is relatively low, minimizing stress shielding. Therefore, we unveiled the glass sintering behavior with concurrent crystallization of this complex bioactive glass composition and developed a potential GC for bone regeneration.     

Foliar Spraying of Silicon Associated with Salicylic Acid Increases Silicon Absorption and Peanut Growth

Silicon - Silicon (Si) combined with foliar spraying of salicylic acid (SA) can affect the absorption of this beneficial element. A study with Si non-accumulators plants (soybean and bean) observed...     

Rheokinematics for product development—Formulation screening in rotational rheometers

Product formulations for industrial processes are typically developed at laboratory scale. However, the mixing conditions are not easily mimicked in the laboratory. A rotational device is proposed in this study as a fast laboratory-scale formulation development, which enables mimicking the mixing conditions in the industrial process. The geometrical configurations of the rotational device are from rheometry devices (plate-plate and cone-plate). The main advantages of this method are the small amounts of raw materials and shorter testing times. This methodology is applied to an industrial case study, the reaction injection molding (RIM) process. The mixing length scales evolution in the rotational rheometer were matched to those in RIM machines. The main novelty of this study is the introduction of a protocol that bridges the processing conditions at laboratory using small amounts of raw materials to high throughput continuous flow reactors.     

Nanocomposite powders of hydroxyapatite-graphene oxide for biological applications

The repair of bone fractures is a clinical challenge for patients with impaired healing, such as osteoporosis. Currently, different strategies have been developed to design new biomaterials, enhancing their interactions with biological systems and conducting the cellular behavior in the desired direction to help fracture healing. In the present work, hydroxyapatite-graphene oxide (HA-GO) nanocomposites were produced and the morphological and physicochemical influences of the addition of 0.5 wt%, 1.0 wt% and 1.5 wt% of GO to HA were observed. FEG-SEM and TEM analyses of HA-GO nanocomposites showed HA nanoparticles adhered to the surface of the GO sheets, suggesting an effective method to form nanostructured graphene-based biomaterials. As confirmation, physicochemical analyses by Raman, FTIR and TGA demonstrated a strong affinity between HA and GO, according to the increase of concentration from 0.5 wt% to 1.5 wt% GO in the HA-GO nanocomposites. Also, in order to evaluate the HA-GO nanocomposites behavior under biological microenvironment, in vitro bioactivity and indirect cytotoxicity tests were performed. FEG-SEM analyses confirmed the positive results for the bioactivity properties of HA-GO nanocomposite and indirect cytotoxicity demonstrated that even with a decrease in the hDPSCs viability and proliferation, when increasing to 1.5 wt% of GO concentration, high level of cell viability was exhibited by HA-GO nanocomposites. These biological results suggested the 0.5 wt% HA-GO nanocomposite as a potential bioactive bone graft and a promising biomaterial for bone tissue regeneration, when compared to the pure HA.     

An automated treatment planning strategy for highly noncoplanar radiotherapy arc trajectories

Radiation therapy is a technology-driven cancer treatment modality that has experienced significant advances over the last decades, due to multidisciplinary contributions that include engineering and computing. Recent technological developments allow the use of noncoplanar volumetric modulated arc therapy (VMAT), one of the most recent photon treatment techniques, in clinical practice. In this work, an automated noncoplanar arc trajectory optimization framework designed in two modular phases is presented. First, a noncoplanar beam angle optimization algorithm is used to obtain a set of noncoplanar irradiation directions. Then, anchored in these directions, an optimization strategy is proposed to compute an optimal arc trajectory. The computational experiments considered a pool of twelve difficult head-and-neck tumor cases. It was possible to observe that, for some of these cases, the optimized noncoplanar arc trajectories led to significant treatment planning quality improvements, when compared with coplanar VMAT treatment plans. Although these experiments were done in a research environment treatment planning software (matRad), the conclusions can be of interest for a clinical setting: automated procedures can simplify the current treatment workflow, produce high-quality treatment plans, making better use of human resources and allowing for unbiased comparisons between different treatment techniques.     

Effect of heat moisture treatment on resistant starch content among carbohydrate sources: a meta-analysis

Resistant starch (RS) can be generated through heat moisture treatment (HMT). The HMT was conducted by modifying starch using different ratio of moisture content, high temperature and heating time. A number of studies showed that the effects of HMT on RS contents in cereals, pulses, tubers and fruits were inconsistent. This study aimed to analyse the impact of HMT on RS level in various carbohydrate sources through a meta-analysis approach. Study selection was conducted with the PRISMA method. There were 21 relevant studies and 67 data used for meta-analysis. The database was analysed by using Hedges’ d. The results showed that there was a significant impact of HMT on RS level of cereals, especially wheat. The highest increase in RS levels for various carbohydrate sources in starch was influenced by the interaction of treatment between water content at 15 ≤ x < 25%, heating time at 0.25 < x ≤ 6 h and temperature at 120 ≤ x ≤ 130 °C.     

Microstructure and flexural strength of the Y:TZP/BG composite

The addition of bioactive glasses to a Y:TZP matrix represents a feasible alternative to provide bioactivity to this material and optimize osseointegration. This work evaluated the effect of the BG concentration (0 and 10 wt%) and the sintering temperature (1200°C and 1300°C) on the microstructure, relative density, and flexural strength of the composite Y:TZP/BG. The Y:TZP and Y:TZP/BG powders were uniaxially pressed and sintered at 1200°C or 1300°C for 1 h. The microstructure was characterized by X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray Spectroscopy. Relative density was calculated from density values obtained using the Archimedes’ principle. For the flexural strength, specimens (n = 6) were fractured in a biaxial flexural setup using a piston-on-three-balls fixture in a universal testing machine. Bioactivity test was performed in simulated body fluid solution. The results suggested that BG addition decreased the grain size of the composite, increased porosity and caused a significant decrease in the relative density and flexural strength. Crystalline phases of calcium stabilized cubic zirconia and sodium zirconium silicate were formed after the addition of BG. Finally, it was concluded that composite specimens sintered at 1300°C showed the highest density values and larger grains compared to those sintered at 1200°C.