Influence of post-processing on the adhesion of dual-species biofilm on polylactic acid obtained by additive manufacturing.

Introduction: Post-processing (PP) is performed to improve the surface, which can favor microbial adhesion and consequent pathological manifestations that impair the indication of polylactic acid (PLA) obtained by fused filament fabrication (FFF) for biomedical applications. This aims to evaluate the influence of chemical, thermal, and mechanical PP on the adhesion of Streptococcus mutants and Candida albicans, roughness, and wettability of the PLA obtained by FFF with and without thermal aging. Methods: The specimens were designed in the 3D modeling program and printed. The chemical PP was performed by immersion in chloroform, the thermal by the annealing method, and the mechanical by polishing. Thermal aging was performed by alternating the temperature from 5 °C to 55 °C with 5000 cycles. Colony-forming unit (CFU/mL) counting was performed on dual-species biofilm of C. albicans and S. mutans. Roughness was analyzed by rugosimeter and wettability by the sessile drop technique. Data were verified for normality using the Shapiro-Wilk test, two-way ANOVA (α = 0.05) applied for CFU and wettability, and Kruskal-Wallis (α = 0.05) for roughness. Results: Chemical, thermal, and mechanical PP methods showed no influence on CFU/mL of C. albicans (p = 0.296) and S. mutans (p = 0.055). Thermal aging did not influence microbial adhesion. Chemical PP had lower roughness, which had increased after aging. Wettability of the mechanical PP was lower. Conclusions: Post-processing techniques, do not present an influence on the adhesion of S. mutans and C. albicans in PLA obtained by FFF, chemical PP reduced roughness, and mechanical reduced wettability. Thermal aging did not alter the microbial adhesion and altered the roughness and wettability.

Reasons for the fatigue of ball attachments and their O-rings: A systematic review.

The ball attachments and their O-rings used for the retention and stabilization of overdentures showed a decrease in retention as the number of cycles increased. This fact resulted in a decrease in the retention of the prosthesis. The purpose of this study was to evaluate the fatigue resistance of ball attachments through a systematic review. An electronic search was performed using the Cochrane Library, LILACS, PubMed, ScienceDirect, and Web of Science databases. The search was conducted based on the PICOS framework. The inclusion criteria involved in the search comprised research articles written in English and published between the years 2000 and 2020. In the final selection, 18 articles were included in the review. Most of these studies performed the fatigue retention tests using parallel implants without angles. However, some studies used different angles to analyze the fatigue retention values. With the passage of time, the wear results in deformation and, as a consequence, a decrease in the retention of most attachments, leading to treatment failure. The main factor to be considered is the loss of retention of these components and their low durability. The loss of retention is due to large extent to the materials used to manufacture the attachments and O-rings, the size and angulation of the implants, and the length of the prosthesis. Future research is needed to further elucidate the reasons for the failure of the attachments.

Lime Rate in Clayey Soils Influences Chemical Fertility and Sugarcane Yield.

Liming contributes to the alleviation of acidity in highly weathered soils. For sugarcane, the use of green harvest methods and new soil tillage systems requires an adjustment of lime application rates. In the present study, the effects of different lime rates and tillage systems on sugarcane performance and soil chemical fertility parameters were assessed. Three experiments were conducted in two locations between April 2015 and October 2019. The study design was a randomized block field study with four replicates. Four lime rates were applied once at sugarcane establishments in each soil tillage system and location: no liming (control); lime recommended rate (LRR); two times LRR (2× LRR); and three times LRR (3× LRR). The three soil tillage systems were conventional (CT), deep-strip (DT), and modified deep-strip tillage (MDT). Soil chemical fertility, leaf nutrient concentrations, and sugarcane yield components were analyzed, and correlations were identified by principal component analysis (PCA). The soil acidity was adequately alleviated in all tillage systems. Increasing the lime rate improved the lime distribution and soil fertility parameters. Applying lime at rates higher than LRR improved stalk and sugar yields, longevity, agronomic efficiency index (AEI), and correlated with a longer residual effect of liming, mainly in the last ratoon.

Carbohydrate Partitioning and Antioxidant Substances Synthesis Clarify the Differences Between Sugarcane Varieties on Facing Low Phosphorus Availability.

Phosphorus (P) availability is important for metabolic process, tillering and formation of a vigorous root system in sugarcane, but sugarcane varieties differ in P uptake efficiency. This study evaluated the enzymatic, nutritional, and biometric parameters of two sugarcane varieties under two conditions of P availability by monitoring the initial development of plants grown in nutrient solution. The experiment was performed using randomized complete block design (RCBD) with five replicates and included two varieties, RB966928 (high nutritional requirements) and RB867515 (low nutritional requirements), and two concentrations of P in the nutrient solution: low (2 mg L-1) and suitable (16 mg L-1). Carbohydrate concentrations and partitioning, leaf nutrient concentrations, enzymatic activity, and shoot and root biometric parameters were analyzed. Regardless of sugarcane variety and the part of the plant, reducing sugar were approximately 32.5% higher in RB867515 and 38.5% higher in RB966928 under suitable P compared with low P. Sucrose concentrations were significantly higher in both varieties under suitable P than in low P. According to PCA, the relationship between reducing sugars and sucrose was closer in RB966928 than in RB867515. Under low P, soluble protein content decreased, and the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and the concentrations of hydrogen peroxide (H2O2), and malondialdehyde (MDA). The variety RB966928 under suitable P appears to have a high capacity for proline (120%) upregulation under abiotic stress compared with RB867515 (54%), and thus higher biomass accumulation of this RB966928 variety; however, RB867515 had superior results compared to RB966928 under low P. Suitable P increased leaf concentrations of N, P, Mg, B, and Mg and decreased leaf Zn content. Root and shoot dry matter, root length, plant height, and root and stalk diameter increased by suitable P. Regardless of variety, both nutritional and biometric parameters were directly influenced by P levels, including sugarcane yield. In relation of sugarcane dry matter, RB966928 was less sensitive to low P levels and more responsive to P supply than RB867515 and thus may be more suitable for environments in which P is limiting.

Nanostructured silver vanadate decorated with silver particles and their applicability in dental materials: A scope review.

OBJECTIVES: The present study aims to evaluate which studies evaluated the effectiveness of incorporating silver vanadate into dental materials and to analyze the influence of this incorporation on antimicrobial activity and material properties. DATA: This review was led by the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist and the JBI Briggs Reviewers Manual to answer the following question:Does the nanostructured silver vanadate decorate with silver particles present anti-microbial activity when incorporated into dental materials without altering its mechanical properties? SOURCE: An electronic search without restriction on the dates or languages was performed in PubMed/MEDLINE, Web of Science, Lilacs, Scopus, and Embase up until 2020. The search was specified and limited to the use of the words "nanostructured silver vanadate" in double quotation marks. STUDY SELECTION: The initial search resulted in 55 articles. After an initial assessment and careful reading, 15 studies published between 2014 and 2020 were included in this review. CONCLUSIONS: With the present scope review, it was possible to observe the good interaction between AgVO3 and dental materials and have a clarity that it is possible to use them in different types of materials in order to reduce the probability of infections resulting from the biofilm that is installed in them.

Degree of phosphorus saturation of an Oxisol amended with biosolids in a long-term field experiment.

When applied to agricultural soils, phosphate fertilizers and the mineral or organic compounds present in solid and/or liquid waste may raise phosphorus (P) content and increase soil P saturation. The degree of phosphorus saturation (DPS) is a good indicator of potential P loss from agricultural soils. The purpose of this study was to calculate the DPS of samples from an Oxisol amended for 5 years with biosolids and mineral fertilizer. DPS was calculated based on P, iron, and aluminum extracted by ammonium oxalate and oxalic acid (DPSox) or by Mehlich-1 solution (DPSM1). Treatments included NPK mineral fertilization (175 kg ha(-1) of P), B1 = 19.02 t ha(-1) of biosolids (350 kg ha(-1) of P), B2 = 38.17 t ha(-1) of biosolids (703 kg ha(-1) of P), B3 = 76.26 t ha(-1) of biosolids (1,405 kg ha(-1) of P), and a control (no P added). Water-extractable P (WEP) was also measured. Critical levels of DPSox and DPSM1 (21 and 24 %, respectively) were only achieved in the topsoil (0-0.1 m) at the highest biosolid dose. Concentration of WEP was positively correlated to DPSox and DPSM1. The DPSM1 method may be an alternative to DPSox for assessing the environmental risk of P loss from soil into surface runoff.