Potentialities of iodine-enhanced micro-CT imaging in the morphological study of adult Aedes (Stegomyia) aegypti (Linnaeus, 1762) mosquitoes.

X-ray micro-computed tomography (CT) produces three-dimensional images of samples on a micrometer scale. This technique has several advantages, such as its nondestructive character and low measurement time, compared with other techniques. However, when applied to biological samples of soft tissue, the low attenuation and low effective contrast between structures pose difficulties in creating appropriate images for morphological studies. Diffusible iodine-based contrast-enhanced CT (DICE-CT), which uses iodine solutions to enhance contrast, is a viable alternative for addressing the aforementioned challenges. Given the variety of biological samples, an appropriate methodology must be adapted depending on the dimensions and morphological characteristics of the investigated object. A specimen that has not been morphologically studied by micro-CT and is of high sanitary importance is the adult Aedes aegypti mosquito. This study investigated the stage of iodine staining in the treatment of the A. aegypti mosquito to determine the most suitable staining time for the morphological study of this mosquito in adulthood. After determining the appropriate staining time, we discuss the potential of applying DICE-CT and methodology to mosquito studies. Seven A. aegypti females were treated using fixation steps with Bouin's solution, dehydration in a graded ethanol series, staining with iodine solution (1%), and washing in absolute ethanol. Only the staining step was different between samples. Each mosquito spent a varying amount of time (6-72 h) in the iodine solution (1%). For comparison, one of the mosquitoes was not stained. After treatment, the samples were scanned using the Bruker SkyScan 1172 micro-CT scanner. The reconstructed volumes and histograms were compared to determine the most suitable time. In addition, a quantitative analysis was performed based on a comparison of the attenuation profiles of the mosquito brains. Thereafter, the most suitable treatment process was selected, and two other samples were scanned after applying the selected process. Although fewer than 18 h was insufficient for an effective increase in attenuation and effective contrast, surpassing 24 h proved unnecessary and resulted in saturating the gray tones visualized through the histograms, leading to information loss. Therefore, a time of approximately 24 h was the most suitable staining time for studying adult A. aegypti. It was possible to isolate the organs of the digestive and reproductive systems of the mosquito stained for 24 h. Thus, micro-CT was confirmed to be an excellent technique in studies of individual structures of adult A. aegypti mosquitoes.

Circulating Concentration of Chemical Elements During Exercise-Induced Muscle Damage and the Repeated Bout Effect.

The objective of the study was to evaluate the circulating levels of chemical elements after exercise-induced muscle damage (EIMD) followed by the repeated bout effect (RBE). Seven physically active subjects (26.5 ± 4.0 years) performed two sessions of EIMD (5 sets of 20 drop jumps), the second session 14 days after the first for RBE assessment. Blood collections, countermovement jump (CMJ), squat jump (SJ), and delayed-onset muscle soreness (DOMS) were performed before (Pre), after (Post), and 24, 48, and 72 h after the exercise session. Creatine kinase (CK) was detected by biochemical analysis and the concentration of chemical elements by total reflection X-ray fluorescence (TXRF). Differences between time points and sessions were assessed with two-way ANOVA and the effect size (ES). EIMD induced a reduction in the CMJ at 24 h (P < 0.05) and an increase in DOMS at 24 h (P < 0.01) and 48 h (P < 0.01), and CK at 72 h (P < 0.05). RBE alleviated all symptoms of EIMD in the second session (P > 0.05). EIMD induced a large to very large ES for Zn reduction at 24 h (- 1.37) and 72 h (- 0.93) and Br (- 0.83) at 72 h. RBE presented large to very large ES for the increase in P at 48 h (0.92); Cl at 24 h (1.04); K at 24 h (0.91), 48 h (1.10), and 72 h (0.96); Ca at 72 h (0.92); and Fe at 24 h (0.85). RBE influenced the concentration of elements associated with fatigue (K, Ca, Cl), inflammatory response, and glucose metabolism (Zn).

The use of BCAA to decrease delayed-onset muscle soreness after a single bout of exercise: a systematic review and meta-analysis.

Branched-chain amino acids (BCAA) are used as a recovery method after exercise-induced muscle damage (EIMD). Although data suggest that BCAA may alleviate the delayed-onset muscle soreness (DOMS) evoked by EIMD, there is no consensus about the most effective supplementation protocol. To investigate the effects of BCAA on DOMS after a single exercise session that caused EIMD, a systematic review and meta-analysis were conducted on the effectiveness of BCAA supplementation to reduce DOMS symptoms in healthy subjects after a single session of EIMD. Randomized clinical trials (RCT) were searched in Medline, Cochrane Library, Science Direct, SciELO, LILACS, SciVerse Scopus, Springer Link journals, Wiley Online Library, and Scholar Google, until May 2021. Ten RCTs were included in the systematic review and nine in the meta-analysis. Seven studies demonstrated that BCAA reduced DOMS after 24 to 72 h. BCAA doses of up to 255 mg/kg/day, or in trained subjects, for mild to moderate EIMD, could blunt DOMS symptoms. However, high variability between studies due to training status, different doses, time of treatment, and severity of EIMD do not allow us to conclude whether BCAA supplementation is efficient in untrained subjects, applied acutely or during a period of pre to post days of EIMD, and at higher doses (> 255 mg/kg/day). The overall effects of BCAA on DOMS after a single session of exercise were considered useful for improving muscle recovery by reducing DOMS in trained subjects, at low doses, in mild to moderate EIMD, and should not be administered only after the EIMD protocol.

Effect of application time and concentration of silver diamine fluoride on the enamel remineralization.

BACKGROUND: Silver diamine fluoride has attracted attention because of its clinical success in arresting dental caries. Thus, the aim of this study was to evaluate the effect of different application times and concentrations of silver diamine fluoride (SDF) on deciduous tooth enamel remineralization. MATERIAL AND METHODS: Blocks of deciduous tooth enamel were categorized into six groups of 11 each: 2 control groups: intact enamel, and demineralized enamel; 38% SDF and 30% SDF which were subdivided according to application times (1 and 3 min). The microhardness of samples was determined, and all groups except the intact enamel group were subjected to pH cycling to produce initial carious lesions. The 38% and 30% SDF solutions were applied to the enamel for 1 or 3 min. After pH cycling and SDF treatments, the microhardness was again determined. Samples were sectioned to evaluate the cross-sectional microhardness. Furthermore, internal porosity of the samples was examined using micro-CT. Data were statistically analyzed by analysis of variance followed by Tukey's test, and linear regression analyses were performed. RESULTS: There was no difference in enamel remineralization based on surface and cross-sectional microhardness. The 30% SDF solution applied for 3 min promoted significantly less pores than the other groups. CONCLUSIONS: The 1-min application time promoted enamel remineralization regardless of the SDF concentration (30% or 38%). Key words:Cariostatic agents, dental caries, primary tooth, tooth remineralization.

Influence of Conventional or Invisalign Orthodontic Treatment on Mineral and Trace Element Salivary Levels: Longitudinal Study with Total Reflection X-ray Fluorescence.

This work aimed to evaluate the salivary concentration of chemical elements in patients undergoing orthodontic treatment with fixed orthodontic appliances and removable aligners. Twelve Angle Class I and II orthodontic patients undergoing treatment with conventional fixed appliances and 15 patients treated with removable aligners provided unstimulated whole saliva samples before treatment (pre) and after 3 months of treatment (post). The concentration and secretion rate of chemical elements in saliva were determined by total reflection X-ray fluorescence. Differences from pre to post and between groups were determined with the paired T test or Wilcoxon test, and two-way ANOVA, considering P < 0.05. The concentrations of S, Cl, and K decreased, while Zn increased significantly (P < 0.05) between pre and post treatment with the fixed appliance treatment. The salivary secretion rate of S was decreased from pre to post in the fixed appliance group. No differences in the concentration and secretion rate of chemical elements were detected from pre to post in the Invisalign group. Fe secretion rate presented an interaction between time and treatment, with lower secretion at post (P = 0.02) in the Invisalign group. Increased Br secretion rate and decreased Rb, Fe, P, and K in Invisalign patients suggested a better salivary electrolyte profile regarding periodontal bone remodeling. No significant alterations in ions associated with metal corrosion and inflammatory reactions were detected in orthodontic patients under dental plaque control.

Higher Speed and No Glide Path: A New Protocol to Increase the Efficiency of XP Shaper in Curved Canals-An In Vitro Study.

INTRODUCTION: This in vitro study compared the performance of the XP-endo Shaper (XP; FKG, La Chaux-de-Fonds, Switzerland) in curved canals when used with a higher speed (3000 rpm) without a glide path with the manufacturer's protocol. METHODS: Twenty extracted mandibular molars with separate mesial curved canals were matched to obtain 2 standardized groups (n = 20). For the XP 1000 group, a glide path up to a size 15 hand file was performed followed by rotary instrumentation with the XP shaper at 1000 rpm, following the manufacturer's recommendations. For the canals in the XP 3000 group, the file was rotated at 3000 rpm after only negotiation the canal with a size 8 hand file (patency file). The operating time and the number of strokes taken to reach the working length (WL) and fit a 30/.04 gutta-percha cone to the WL were recorded. The shaping abilities were evaluated by micro-computed tomographic imaging and file deformation by scanning electron microscopy. Data were analyzed using analysis of variance and chi-square tests at a 5% significance level. RESULTS: The XP 3000 group required less time and strokes to reach the WL (P < .05) and resulted in a higher percentage of adequate cone fit (P < .05). No difference was found between groups regarding the micro-CT parameters, except for the taper, which was larger in the XP 3000 group in the apical and middle thirds (P < .05). No difference was found regarding file deformation between the 2 groups. CONCLUSIONS: The suggested protocol for the use of the XP (3000 rpm without a glide path) appears to be more efficient than the manufacturer's recommended protocol to prepare curved canals in vitro.

Morphological study of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) eggs by X-ray computed microtomography.

Aedes aegypti and Aedes albopictus are vectors of several arboviruses responsible for causing dengue, chikungunya, Zika, and yellow fever viruses and microcephaly, resulting in a public health problem in several countries worldwide. Even in this scenario, studies on the morphology of mosquito eggs are still lacking. In this paper, X-ray microtomography was used to study mosquito egg morphology. Several parameters such as length, surface area, volume, area-by-volume ratio, eccentricity and center of mass of the eggs were determined. The results obtained showed that micro-CT is an efficient technique for the morphological study of insect eggs and provides information that cannot be obtained with other techniques.

Effect of light-curing protocols on the mechanical behavior of bulk-fill resin composites.

OBJECTIVE: To investigate the effect of two light-curing protocols on mechanical behavior of three bulk-fill resin composites (BFRC) considering their optical properties. METHODS: One increment of 4 mm thickness of the bulk-fill resin composites Opus Bulk Fill, Tetric N-Ceram and Filtek Bulk Fill Flow were submitted to two different light-curing protocols: Sp - irradiance of 1000 mW/cm2 (20 s); Xp - irradiance of 3200 mW/cm2 (6 s). To assess the influence on the mechanical behavior it was studied polymerization shrinkage by X-ray microtomography (n = 3), Vickers hardness (n = 10) at the top and bottom surfaces of the samples, irradiance reaching the bottom surface (n = 3) and absorbance spectrum during the light-curing time interval (n = 3). Data were analyzed by two-way ANOVA test for parametric data and Kruskal Wallis test, followed by Wilcoxon or Mann-Whitney U post-test, for non-parametric data. RESULTS: All BFRCs contracted when light-cured, with greater contraction for Xp. Filltek Bulk Fill Flow showed highest polymerization shrinkage, for both Sp and Xp. All BFRCs showed minor hardness values on the bottom surface, with greater reduction for Xp. All BFRCs exhibited a decrease in irradiance at 4 mm depth. A decrease in absorbance intensity throughout the light-cure was observed, except for Opus Bulk Fill. CONCLUSIONS: Regardless BFRCs composition, the light-curing protocol with lower irradiance and longer exposure time results in lower polymerization shrinkage and higher hardness. The higher irradiance in a shorter time interval compromises the mechanical behavior of the resin composites, which may result in undesirable clinical outcomes.

A Micro-computed Tomographic Evaluation of the Accuracy of 3 Electronic Apex Locators in Curved Canals of Mandibular Molars.

INTRODUCTION: This study evaluated the accuracy of 3 electronic apex locators (EALs) (CanalPro [Coltene-Endo, Cuyahoga Falls, OH], Apex ID [SybronEndo, Glendora, CA], and Root ZX Mini [J Morita, Tokyo, Japan]) in curved mesial canals of extracted mandibular molars using micro-computed tomographic (micro-CT) scanning. METHODS: The root canal length and the actual working length of 58 canals were measured using the visual method and 3-dimensional micro-CT reconstructions. The measurements of the EALs at marks "APEX/0.0" and "0.5 mark" were recorded as the electronic root canal length and the electronic working length, respectively. The absolute mean values and the percentages of distribution of the electronic measurements were compared with the actual lengths of the canals. The presence of isthmuses, accessory canals, foramen position, and the distance between the apical constriction and the apical foramen were recorded from the micro-CT scans, and their correlation to the accuracy of the EALs was determined. RESULTS: All electronic measurements showed high agreement with their respective gold standard, except the electronic root canal length of the Apex ID (P < .05). No difference in the percentage of precise measurements (within the ±0.5 mm) was found among the devices (χ2 and z tests, P > .05). Of the anatomic parameters evaluated, the presence of a lateral foramen negatively affected the 0.0 mark of the Apex ID (Wilcoxon test, P < .05). CONCLUSIONS: The Root ZX Mini and CanalPro were precise for both root canal length and working length determination in mesial curved canals of mandibular molars, whereas the Apex ID was accurate for the working length when using the 0.5 mark.

Determining chemical composition of materials through micro-CT images.

X-ray microtomography is a 3D non-destructive method which, through digital images, enables a view of the internal structure of samples. Recently, researchers have been extensively performing various methods in the attempt to determine the chemical composition of materials. This paper brings further insight into this matter and proposes a new experimental method for determining the internal chemical composition of samples. Using a set of standard samples, calibration curves can be created that allow to relate the average gray scale of a sample obtained through microtomographic images to the value of ρZeff(m). In this model, ρZeff(m) is the parameter that chemically characterizes a material. The exponent m is obtained by the average value obtained with standard samples, which were titanium dioxide (TiO2), calcium chloride (CaCl2), calcium hydroxide (Ca(OH)2), and calcium nitrate (Ca(NO3)2). For the samples scanning process, a Bruker SkyScan 1172 microCT was used for testing rocks, nylon, graphite, calcium carbonate (CaCO3) and aluminum samples. The experimental results achieved by this method were consistent with the theoretical values.

Effective atomic number and density determination of rocks by X-ray microtomography.

Microtomography, as a non-destructive technique, has become an important tool in studies of internal properties of materials. Recently, interest using this methodology in characterizing the samples with respect to their compositions, especially rocks, has grown. Two physical properties, density and effective atomic number, are important in determining the composition of rocks. In this work, six samples of materials with densities that varied from 2.42 to 6.84g/cm(3) and effective atomic numbers from 15.0 to 77.3 were studied. The measurements were made using a SkyScan-Bruker 1172 microtomography apparatus operating in voltages at 50, 60, 70, 80, 90 and 100kV with a resolution of 13.1µm. Through micro-CT images, an average gray scale was calculated for the samples and correlation studies of this value with the density and the effective atomic number of samples were made. Linear fits were obtained for each energy value. The obtained functions were tested with samples of Amazonite, Gabbro, Sandstone and Sodalite.