The effects of muscle starting length on work loop power output of isolated mouse soleus and extensor digitorum longus muscle.

Force-length relationships derived from isometric activations may not directly apply to muscle force production during dynamic contractions. As such, different muscle starting lengths between isometric and dynamic conditions could be required to achieve maximal force and power. Therefore, this study examined the effects of starting length [±5-10% of length corresponding to maximal twitch force (L0)] on work loop (WL) power output (PO), across a range of cycle frequencies, of the soleus (SOL) and extensor digitorum longus muscle (EDL; N=8-10) isolated from ∼8 week old C57 mice. Furthermore, passive work was examined at a fixed cycle frequency to determine the association of passive work and active net work. Starting length affected maximal WL PO of the SOL and EDL across evaluated cycle frequencies (P<0.030, ηp2>0.494). For the SOL, PO produced at -5% L0 was greater than that at most starting lengths (P<0.015, Cohen's d>0.6), except -10% L0 (P=0.135, d<0.4). However, PO produced at -10% L0 versus L0 did not differ (P=0.138, d=0.35-0.49), indicating -5% L0 is optimal for maximal SOL WL PO. For the EDL, WL PO produced at -10% L0 was lower than that at most starting lengths (P<0.032, d>1.08), except versus -5% L0 (P=0.124, d<0.97). PO produced at other starting lengths did not differ (P>0.163, d<1.04). For the SOL, higher passive work was associated with reduced PO (Spearman's r=0.709, P<0.001), but no relationship was observed between passive work and PO of the EDL (Pearson's r=0.191, r2=0.04, P=0.184). This study suggests that starting length should be optimised for both static and dynamic contractions and confirms that the force-length curve during dynamic contractions is muscle specific.

Effect of EDDY and manual dynamic activation techniques on postoperative pain in non-surgical retreatment: a randomized controlled trial.

BACKGROUND: During non-surgical retreatment process, the products such as dentin debris, root canal fillings, irrigation solutions, microorganisms and remaining pulp tissues can extrude to the apical area and can cause the postoperative pain and flare-up. Thus, the aim of this study was to evaluatethe effect of EDDY and manual dynamic activation (MDA) techniques on postoperative pain (PP) associated with retreatment. METHODS: Ninety patients scheduled for retreatment were treated at a single visit. Non-vital mandibular premolar teeth diagnosed with asymptomatic apical periodontitis were included in this study. The patients were divided into two groups (n = 45) on the basis of the need for additional irrigation activation procedures (EDDY and MDA). The patients' post-treatment pain levels were asked to rate the intensity of their pain on a 10-point numerical rating scale (NRS) at the 12th, 24th, 48th, and 72nd h and 7 days.The data were analyzed using the chi-square and Wilcoxon signed-rank test was used for within-group comparisons and Mann Whitney U test was used to compare the groups by time period. RESULTS: The difference in postoperative pain intensity between two groups was statistically significant at 12, 24, 48, and 72 h (p < 0.05). There was no significant difference at 7 days. Moreover, no statistically significant difference was found between the two groups in terms of gender and analgesic medication intake (p > 0.05). Pain intensity after the treatment was lesser in the MDA groupthanin the EDDY group at 12, 24, 48, and 72 h. CONCLUSION: This study could lead us to conclude that the two activation systems can be used during endodontic retreatment with no difference at PP 7 days later. However, a comparison of the groups indicated that the EDDY resulted in significantly more PP at 12, 24, 48, and 72 h. Trial registration ClinicalTrials.gov Identifier: NCT04726670.

The influence of irrigant activation, concentration and contact time on sodium hypochlorite penetration into root dentine: an ex vivo experiment.

AIM: To establish whether irrigant activation techniques, namely manual dynamic activation (MDA), passive ultrasonic irrigation (PUI) and sonic irrigation (SI), improve the tubular penetration of sodium hypochlorite (NaOCl) into root dentine when compared with conventional needle irrigation (CNI). Secondly, investigate if increasing NaOCl concentration and/or contact time improves the performance of these techniques. METHODOLOGY: A total of 83 extracted human maxillary permanent canines were decoronated to 15 mm, and root canals prepared to a size 40, .10 taper. Root dentine was stained with crystal violet for 72 h and embedded in silicone. Eighty specimens were randomly distributed into 16 groups (n = 5) according to the irrigant activation technique, NaOCl concentration (2%; 5.25%) and irrigant contact time (10 min; 20 min). All activation techniques were used for 60 s in the last minute of irrigation. Additionally, three teeth were not exposed to NaOCl to confirm adequate dentine staining had occurred (i.e. negative control). All specimens were subsequently dissected, observed under a light microscope and NaOCl penetration depth (µm) determined by measuring the average width of bleached dentine using ImageJ software. Statistical comparisons were made with paired and unpaired t-tests, anovas followed by post hoc Tukey's and Dunnett's tests, and a general linear model (α < 0.05). RESULTS: Overall, NaOCl penetration ranged from 38.8 to 411.0 µm with MDA, PUI and SI consistently resulting in significantly greater tubular infiltration than CNI (P < 0.05). The deepest measurements in the coronal, middle and apical segments were all recorded in the MDA; 5.25%; 20 min group and the least in the CNI; 2%; 10 min group. Increasing either irrigant concentration or contact time resulted in significantly greater NaOCl penetration depths for all techniques and segments of the canal (P < 0.05). However, when irrigant concentration and contact time were increased together, a significant interaction effect between these two independent variables was observed on overall NaOCl penetration (P < 0.05). CONCLUSIONS: Agitating irrigants with MDA, PUI or SI, as well as using greater irrigant concentrations or contact times, potentiated NaOCl penetration into root dentine. However, longer durations of NaOCl exposure at lower concentrations resulted in similar depths of tubular penetration as those achieved at higher concentrations.

Effectiveness of complementary irrigation routines in debriding pulp tissue from root canals instrumented with a single reciprocating file.

AIM: To compare histologically the debridement efficacy of four irrigation techniques in root canals instrumented with a reciprocating single file. METHODOLOGY: From recently extracted premolars with vital pulp, 68 were selected and classified as having round canals (mesiodistal diameter similar to buccolingual) or oval-shaped canals (mesiodistal diameter 2.5 times larger than buccolingual) (n = 32, each) by means of bidirectional radiographs. Four additional uninstrumented samples served as histological controls. The root canals of the specimens were accessed and then instrumented with Reciproc R25® and further assigned to one of four experimental groups according to the complementary irrigation technique: Group I, conventional syringe; Group II, passive ultrasonic irrigation; Group III, manual dynamic activation (MDA); and Group IV, EndoActivator® . Roots were then demineralized and the apical 3 mm was multi-sliced and processed for histologic examination. The percentage of residual pulp tissue was calculated at each cross section. Kruskal-Wallis and Mann-Whitney tests were used to evaluate the effects of irrigation technique, root canal shape and level of cross section on the percentage of residual pulp tissue (P < 0.05). RESULTS: Irrigation technique and root canal shape significantly influenced the percentage of residual pulp tissue (P < 0.05) of canals instrumented with the R25 instrument. Percentage of residual pulp tissue was significantly less using ultrasonic irrigation (P < 0.05), but there was no difference between other irrigation techniques (P > 0.05). Round canals retained significantly less percentage of residual pulp tissue compared to oval-shaped canals (P = 0.001). At 3 mm, there was less pulp tissue compared to levels 2 and 1 mm (P < 0.05). CONCLUSIONS: In canals instrumented with R25 files, ultrasonic irrigation was more effective in removing pulp tissue in the apical level, especially for the debridement of oval-shaped canals.

Evaluation method for the measuring comprehensive suitability of chelating agents: a study of the temporal dynamics of heavy metal activation.

The effects of chelating agents on heavy metal activation in Cd- and Pb-contaminated soils were studied through a dynamic activation experiment. An evaluation method for the measuring comprehensive suitability of chelating agent was established by calculating indexes for the degree of activation effect suitability and activated heavy metals' half-life suitability. The following results were obtained: in Cd- and Pb-contaminated soils, heavy metal activation effects reached or approached maximum activating effects within 1 d and subsequently showed different levels of decline in all chelating agent treatment conditions. Declines in activation effects similarly subjected to the law of exponents over time and to the goodness of fit in DTPA, NTA, and GLDA ranged from 0.80 to 0.98. For Cd- and Pb-contaminated soils, chelating agents' levels of comprehensive suitability (H) were recorded as follows: NTA(1.40) > GLDA(1.31) > DTPA(1.14) > EDTA(1.00) > EDDS(0.14) > CA(0.06) and GLDA(1.56) > DTPA(1.48) > EDTA(1.00) > NTA(0.78) > EDDS(0.26) > CA (0.02). GLDA and DTPA are both suitable for Cd and Pb phytoextraction. Moreover, NTA and GLDA are optimal chelating agents for Cd and Pb phytoextraction, respectively.

Visualization of the Dynamic Brain Activation Pattern during a Decision-Making Task.

Decision making is a complex process involving various parts of the brain which are active during different times. It is challenging to measure externally the exact instant when any given region becomes active during the decision-making process. Here, we propose the development and validation of an algorithm to extract and visualize the dynamic functional brain activation information from the observed fMRI data. We propose the use of a regularized deconvolution model to simultaneously map various activation regions within the brain and track how different activation regions changes with time, thus providing both spatial and temporal brain activation information. The proposed technique was validated using simulated data and then applied to a simple decision-making task for identification of various brain regions involved in different stages of decision making. Using the results of the dynamic activation for the decision-making task, we were able to identify key brain regions involved in some of the phases of decision making. The visualization aspect of the algorithm allows us to actually see the flow of activation (and deactivation) in the form of a motion picture. The dynamic estimate may aid in understanding the causality of activation between various brain regions in a better way in future fMRI brain studies.

Evaluation of Ozone Therapy in Endodontic Treatment of Teeth with Necrotic Pulp and Apical Periodontitis: A Randomized Clinical Trial.

INTRODUCTION: The aim of this study was to compare the effect of different application techniques of ozone on the prevalence of postendodontic pain in patients undergoing single-visit root canal treatment. METHODS: hundred eight patients with necrotic pulp in single-rooted teeth and apical periodontitis participated in the trial. A standard single-visit endodontics protocol was followed with 5.25% sodium hypochlorite and rotary nickel-titanium files. After shaping and cleaning, patients were randomly allocated into the following groups: group 1 (n = 21), ozone treatment with no activation (NA); group 2 (n = 22), ozone treatment with manual dynamic activation (MDA); group 3, (n = 21), ozone treatment with passive ultrasonic activation (PUA); group 4 (n = 23), ozone treatment with sonic activation (SA); and group 5 (n = 21), no ozone treatment (the control group). Patient levels of discomfort were recorded at 6 different time intervals using the visual analog scale (VAS). Comparison of the mean difference between the groups and time intervals was performed using 2-way analysis of variance followed by a post hoc Bonferroni test. The level of significance was set at 5%. RESULTS: VAS scores were highest for the control > NA > MDA > SA > PUA groups. A statistically significant reduction in VAS scores was observed in the PUA and SA groups in comparison with the NA, control, and MDA groups. Timewise comparison showed a highly significant decline in VAS scores at all time intervals (P < .001). CONCLUSIONS: Ultrasonic and sonic activation of ozone resulted in less pain in patients undergoing single-visit endodontics compared with no ozone treatment.

Comparison of Five Different Irrigation Techniques on Smear Layer Removal in Apical Thirds of Root Canals of Mandibular First Premolar: A Scanning Electron Microscopic Study.

AIM: This study was conducted to compare smear layer removal by five different irrigation techniques-conventional needle irrigation (CI), manual dynamic activation (MDA), passive ultrasonic irrigation (PUI), sonic irrigation (SI), and negative apical pressure (NAP). MATERIALS AND METHODS: Fifty freshly extracted mandibular first premolars were cleaned and shaped by One Curve rotary files and 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. The samples were divided into five equal groups (n = 10), according to the final irrigation activation technique: Group I, CI; Group II, MDA; Group III, PUI; Group IV, SI; and Group V, NAP. The samples were prepared and observed under a scanning electron microscope. The photomicrographs were recorded and evaluated with a scoring system. RESULTS: Group I and Group II had the highest scores, which showed a statistically significant difference between the other groups (P < 0.05). This was followed by PUI, NAP, and SI. CONCLUSION: Final irrigation activation with SI and NAP resulted in the better removal of smear layer when compared to that with other groups.

Resonance-Activated Spin-Flipping for Efficient Organic Ultralong Room-Temperature Phosphorescence.

Triplet-excited-state-involved photonic and electronic properties have attracted tremendous attention for next-generation technologies. To populate triplet states, facile intersystem crossing (ISC) for efficient exciton spin-flipping is crucial, but it remains challenging in organic molecules free of heavy atoms. Here, a new strategy is proposed to enhance the ISC of purely organic optoelectronic molecules using heteroatom-mediated resonance structures capable of promoting spin-flipping at large singlet-triplet splitting energies with the aid of the fluctuation of the state energy and n-orbital component upon self-adaptive resonance variation. Combined experimental and theoretical investigations confirm the key contributions of the resonance variation to the profoundly promoted spin-flipping with ISC rate up to ≈107 s-1 in the rationally designed NPX (X = O or S) resonance molecules. Importantly, efficient organic ultralong room-temperature phosphorescence (OURTP) with simultaneously elongated lifetime and improved efficiency results overcoming the intrinsic competition between the OURTP lifetime and efficiency. With the spectacular resonance-activated OURTP molecules, time-resolved and color-coded quick response code devices with multiple information encryptions are realized, demonstrating the fundamental significance of this approach in boosting ISC dynamically for advanced optoelectronic applications.

Effect of manual dynamic activation with citric acid solutions in smear layer removal: A scanning electron microscopic evaluation.

BACKGROUND/PURPOSE: Chelating agents have been used for the removal of the smear layer on teeth. However, due to inadequate volume and/or penetration of the solutions during irrigation, smear layer removal is less effective in the apical third. The purpose of this study was to compare the efficacy of three chelating solutions with and without manual dynamic irrigation in smear layer removal. MATERIALS AND METHODS: Sixty-six single-root canal teeth were decoronated, instrumented, and divided into six experimental groups (n = 10) and two control groups (n = 3). The groups received a final rinse with 1 mL of 17% EDTA and 5% or 10% citric acid (CA) for 1 minute, with or without manual dynamic activation, followed by a final 3-mL rinse with 4.2% NaOCl (5 minutes). The teeth were then longitudinally split and prepared for environmental scanning electron microscopy analysis. Digital images (500×) were taken for smear layer removal evaluation at 2 mm, 6 mm, and 10 mm from the working length. RESULTS: The most effective smear layer removal occurred with 5% and 10% CA combined with manual dynamic activation (Groups 7 and 8), where significant differences were observed when compared with the EDTA groups (Groups 2 and 6; P < 0.05). We found no significant differences between manual dynamic activation with 5% and 10% CA (Groups 7 and 8) in smear layer or debris removal (P > 0.05). CONCLUSION: Manual dynamic activation of CA improves smear layer removal, and a reduction in CA concentration to 5% does not compromise smear layer removal in comparison with higher concentrations.

Comparación de tres técnicas de irrigación en la remoción de hidróxido de calcio / Comparison of three irrigation techniques in the removal of calcium hydroxide

Objetivos: Comparar la eficacia de tres de protocolos de irrigación en la remoción de hidróxido de calcio (Ca(OH)2) Material y Métodos: Mediante un diseño de estudio comparativo in vitro, se instrumentaron 106 conductos radiculares de incisivos bovinos hasta una lima de diámetro 60, la raíces se fraccionaron en dos mitades siguiendo el eje mayor del diente y se creó un surco estandarizado a 2 mm del agujero apical que fue rellenado con una pasta de hidróxido de calcio, luego se reensamblaron las mitades, se incubaron por 7 días y se realizaron los protocolos de irrigación: ultrasónica pasiva (PUI), sónica con Endo Activator (EA) y activación dinámica manual (MDA), donde se usó como irrigante hipoclorito de sodio (NaOCl) al 5%. Se utilizó un control negativo y positivo. Con un estereomicroscópio se observó la cantidad de residuo, las imágenes se examinaron y se les asignó una puntación de acuerdo a la escala de van der Sluis, finalmente los datos se analizaron con la prueba estadística del Chi Cuadrado. Resultados: Los porcentajes de eficacia para los protocolos de irrigación PUI, EA y MDA fueron del 87,5%; 46,9% y 28,1% respectivamente, la técnica PUI fue superior a EA y MDA y obtuvo diferencias estadísticamente significativas (p<0,001). Conclusiones: PUI fue el método más efectivo en la remoción de Ca(OH)2 de los surcos simulados en los conductos radiculares.

Objectives: To compare efficacy of three irrigation protocols in the removal of calcium hydroxide (Ca(OH)2). Materials and Methods: Through an in vitro comparative study design, 106 root canals of bovine incisors were instrumented up to a file of diameter 60, the roots were fractioned into two halves following the major axis of the tooth and a standardized groove was created 2mm from the apical foramen that was filled with a paste of calcium hydroxide, then the halves were reassembled, incubated for 7 days and the irrigation protocols were carried out: passive ultrasonic (PUI), sonic with Endo Activator (EA) and manual dynamic activation (MDA), where 5% sodium hypochlorite (NaOCl) was used as irrigant. A negative and positive control was used. With a stereomicroscope the amount of residue was observed, the images were examined and assigned a score according to the van der Sluis scale, finally the data were analyzed with the statistical test of Chi-square. Results: The percentages of efficacy for PUI, EA and MDA irrigation protocols were 87.5%; 46.9% and 28.1% respectively, the PUI technique was superior to EA and MDA and obtained statistically significant differences (p <0.001). Conclusions: PUI was the most effective method in the removal of Ca(OH)2 from the simulated grooves in the root canals.