Cycle Intervals Research Articles

Research on the Effect of Freeze-Thaw Cycles at Different Temperatures on the Pore Structure of Water-Saturated Coal Samples.

To study the pore structure transformation of coal at different temperatures, freeze–thaw cycle experiments at different temperature intervals (20 to −20 °C, 20 to −40 °C, 20 to −196 °C) were carried out. The low-field nuclear magnetic resonance equipment was used to characterize the peak area, pore size distribution, and pore number of each group of coal samples. The pore transformation effect of coal samples at different temperature intervals was compared, and the change characteristics of the pore structure of coal samples under the freeze–thaw action were explored. The research shows that the freeze–thaw cycles at different freezing temperature intervals have obvious differences in the effect of coal pore transformation. The area of each peak spectrum in the T2 distribution curve of coal samples increased significantly under the action of freeze–thaw cycles in different freezing temperature intervals. The increased value of the number of mesopores and macropores shows the phenomenon of “first increase and then decrease” with the increase of the temperature difference. There is a quadratic function relationship between the temperature difference in the freezing temperature interval and the proportion change rate of the adsorption pore or seepage pore. The continuous increase of the temperature difference has a certain marginal effect on the proportion change rate of seepage pores and adsorption pores in coal.

DICKINSONIA COSTATA of the Winter Mountains: Features of morphology and ontogenesis

The remains of Ediacaran (Vendian) macrofossils from the Zimnie Gory (Winter Mountains) locality (Russia, southeastern White Sea area) are used to characterize one of the classic animals of the Late Precambrian, Dickinsonia costata. The Zimnie Gory material shows that the body of this species, like that of other species of Dickinsonia, was divided into “half-segments” (isomers) arranged in two rows in alternating order. This makes it possible to classify Dickinsonia as an Ediacaran phylum of Metazoa, Proarticulata. D. costata appeared in the benthic community with a body diameter of about 1 mm and the possible absence of transverse differentiation. D. costata from Zimnie Gory grew to very large sizes, reaching a length of 390 mm and having at least 225 pairs of isomers. During the ontogeny of D. costata, there was a significant change in the shape and relative size of the anterior lobe and a multiple increase in the number of isomers. At the same time, in contrast to other dickinsonias, the general body proportions of D. costata from Zimnie Gory varied slightly towards a slight decrease in the relative width. The addition of new isomers occurred during the entire observed interval of the life cycle of this Dickinsonia. Based on this, the growth pattern of D. costata is defined as allometric and indeterminate.

A Comparative Evaluation of Wear of Enamel to Various Restorative Materials of Different Surface Finishes-An In Vitro Study

Aim:The aim of this study is to evaluate the effect of different surface finish of various restorative materials on the wear of opposing enamel.Objectives of the study:1.To compare the amount of enamel loss in experimental groups of various restorative materials at different intervals of masticatory cycles. 2.To compare and evaluate the most compatible finished or polished surface of the restorative material causing least enamel wear. Materials and Methods: A total of 90 samples were prepared for this study - 75 in disc form and 15 enamel antagonist and divided into 6 groups. Group 1 - Enamel vs Enamel antagonist, Group 2 - Enamel vs Fiber Reinforced Composite disc, Group 3 Enamel vs Autoglazed metal ceramic disc , Group 4 - Enamel vs Overglazed metal ceramic disc, Group 5 - Enamel vs Polished metal ceramic disc by polishing kit, and Group 6 - Enamel vs PEEK disc were fabricated. 105 extracted premolars were collected and randomly divided into six groups of 15 each and 15 for enamel antagonist. Each tooth sample was weighed before wear testing using electronic analytical balance of 0.0001 g accuracy. Occlusal surfaces of these teeth were then abraded against the substrates in a wear machine for a total of 10,000 cycles. Each tooth sample was weighed after 5000 cycles and after the total of 10,000 cycles, respectively, using the same balance. Differences in weight of tooth samples before and after wear testing were evaluated statistically using One-way analysis of variance and Tukey’s post hoc tests was used. Results: The values obtained for overall mean percentage weight loss after 10000 rotations in increasing order is observed: Group 1 (Enamel Vs Enamel 0.0043 ± 0.00) < Group 6 (Enamel Vs PEEK disc 00.0131 ± 0.01) < Group 2 (Enamel Vs Fiber reinforced composite 0.0258 ± 0.01) < Group 5 (Enamel Vs Polished metal ceramic disc 0.0294 ± 0.00) < Group 3 (Enamel Vs Autoglazed metal ceramic disc 0.0318 ± 0.01) < Group 4 (Enamel Vs Overglazed ceramic disc 0.0451 ± 0.01). Conclusion:PEEK showed the least amount of enamel wear followed by Fiber reinforced composite. Fiber reinforced composite may cause less wear than dental ceramics. Enamel wear produced by polished metal ceramic disc is substantially less than autoglazed and over glazed metal ceramic disc. This study indicates that any potential damage to ceramic can directly affect enamel and suggests that porcelain should be polished instead of over glazed.
 Key Words: Fiber reinforced composite, Autoglazed, Overglazed, Polished surface, Wear, PEEK.

Muscle Fatigue Is Attenuated When Applying Intermittent Compared With Continuous Blood Flow Restriction During Endurance Cycling.

The aim of this study was to identify a blood-flow-restriction (BFR) endurance exercise protocol that maximizes metabolic strain and minimizes muscle fatigue. Twelve healthy participants accomplished 5 different interval cycling endurance exercises (2-min work, 1-min rest) in a randomized order: (1)control, low intensity with unrestricted blood flow (CON30); (2)low intensity with intermittent BFR (i-BFR30, ∼150mm Hg); (3)low intensity with continuous BFR (c-BFR, ∼100mm Hg); (4)unloaded cycling with i-BFR0 (∼150 mm Hg); and (5)high intensity (HI) with unrestricted blood flow. Force production, creatine kinase activity, antioxidant markers, blood pH, and potassium (K+) were measured in a range of 5 minutes before and after each cycling exercise protocol. HI showed the highest reduction (Δ = -0.26 [0.05], d = 5.6) on blood pH. Delta pH for c-BRF30 (Δ = -0.02 [0.03], d = 0.8) and ΔpH for i-BRF30 (Δ = -0.04 [0.03], d = 1.6) were different from each other, and both were higher compared with CON30 (Δ = 0.03 [0.03]). There was significant before-to-after force loss following HI (Δ = 55 [40]N·m-1, d = 1.5) and c-BFR30 (Δ = 27 [21]N·m-1, d = 0.7) protocols only, which were accompanied by significant increases in K+ (HI: Δ = 0.94 [0.65]mmol·L-1, d = 1.8; c-BFR30: Δ = 0.72 [0.85]mmol·L-1, d = 1.2). Moreover, all BFR conditions elicited slight increases in plasma creatine kinase, but not for HI and CON30. Glutathione changes from before to after were significant for all BFR conditions and HI, but not for CON30. The attenuation in fatigue-induced reductions in maximal force suggests that i-BFR exercise could be preferable to c-BFR in improving exercise capacity, with considerably less biologic stress elicited from HI exercises.

Acute Effects of Concurrent High-Intensity Interval Cycling and Bench-Press Loading on Upper- and Lower-Body Explosive Strength Performance.

This study examined the acute effects of lower-body high-intensity interval loading (HIIT) on explosive upper- and lower-body strength, as well as the combined effect of HIIT and bench-press loading versus HIIT and squat loading on the explosive upper- and lower-body strength. Fifteen physically active men completed 2 sessions consisting of HIIT (4 × 4min cycling at 80% of peak power output) immediately followed by lower- (HIIT + LBS) or upper-body (HIIT + UBS) strength loading (3 × 5 + 3 × 3 repetitions at 80% 1-repetition maximum [ie,6 sets in total]) in a randomized order. Squat and bench-press mean propulsive velocity (MPV) was assessed before HIIT (T0), immediately after HIIT (T1), immediately after the strength loading (T2), and 24hours after the experimental session (T3). Squat MPV decreased to a similar magnitude at T1 in HIIT + LBS (-5.3% [7.6%], P = .117, g = .597) and HIIT + UBS (-5.7% [6.9%], P = .016, g = .484), while bench press remained unchanged (-1.4% [4.7%], P = 1.000, g = .152, and -1.0% [7.0%], P = 1.000, g = .113, respectively). Both squat and bench-press MPV were statistically reduced at T2 compared to T0 (HIIT + LBS: -7.5% [7.8%], P = .016, g = .847, and -6.8% [4.6%], P < .001, g = .724; HIIT + UBS: -3.9% [3.8%], P = .007, g = .359, and -15.5% [6.7%], P < .001, d = 1.879). Bench-press MPV at T2 was significantly lower in HIIT + UBS when compared to HIIT + LBS (P = .002, d = 1.219). These findings indicate lower- but not upper-body explosive strength to be acutely reduced by preceding lower-body HIIT. However, lower-body HIIT combined with either upper- or lower-body strength loading resulted in a similar acute reduction of both squat and bench-press explosive strength.

Prediction of fatigue crack propagation lives based on machine learning and data-driven approach

Numerous influence factors will lead to the inaccurate prediction of fatigue crack propagation (FCP) life of the metal structure based on the existing FCP model, while the prediction method based on machine learning (ML) and data-driven approach can provide a new idea for accurately predicting the FCP life of the metal structure. In response to the inconvenience of the online prediction method and the inaccuracy of the offline prediction method, an improved offline prediction method based on data feedback is presented in this paper. FCP tests of reduced scale models of balcony opening corners in a cruise ship are conducted to obtain experimental data with respect to the a-N curves. The crack length corresponding to the cycle is trained using a support vector regression (SVR) and back propagation neural network (BP NN) algorithms. FCP prediction lives of test specimens are performed according to the online, offline, and improved offline prediction methods. Effects of the number of feedback data, the sequence length (SL) in the input set, and the cycle interval on prediction accuracy are discussed. The generalization ability of the proposed method is validated by comparing the prediction results with the experimental data in the literature. The larger the number of feedback data, the higher the prediction accuracy. The results show that 1/5 and 1/2 feedback data are needed in the SVR and BP NN algorithm with SL is 5, respectively. Furthermore, the SVR algorithm and SL=5 are recommended for FCP life prediction using the improved offline prediction method.

Alkenones in Pleistocene Upper Bed I (1.803–1.900 Ma) sediments from Paleolake Olduvai, Tanzania

The Olduvai Gorge Coring Project (OGCP) recovered sequences of Pleistocene lake sediments that correlate with those known from outcrops directly associated with hominin fossil horizons. The sedimentary succession from Core 2A (02° 58′ 43′' S, 035° 19′ 25.5′' E), which targeted the ancient lake-basinal depocenter, includes stratigraphic intervals (∼1.86 Ma) sandwiched between the Bed I basalt and Tuff IF dated horizons, where remains of two hominin holotypes have been recovered. The lower part of this sequence (72.3–86.9 mbs) consists of lacustrine claystones interbedded with sandy claystones characterized by high Corg (av. 2.5%) and includes several laminated intervals. It displays shifts in terrestrial vegetation recorded by values for δ13CTOC and δ2HnC31 that reflect changes in the proportions of C3 vs C4 plants and precipitation, respectively. These temporal profiles represent higher-resolution signatures of the precession-scale wet/dry cycles previously recognized in the outcropping sedimentary succession of Olduvai Gorge. Several samples from this interval contain alkenones comprising C37 and C39 alkadien-2-ones and alkatrien-2-ones, and C38 and C40 alkadien-3-ones and alkatrien-3-ones. They are distinguished from the vast majority of alkenone distributions reported in lake sediments from polar and temperate latitudes (e.g., Greenland, N. and S. America, Europe, Russia, China, S. Africa, Antarctica) by the absence of tetraunsaturated alkenones (e.g., C37:4). The alkenone distributions vary stratigraphically with higher concentrations in the drier intervals of the precession-scale cycles that exhibit characteristics resembling those of Group II haptophytes found in contemporary saline/alkaline environments rather than those of Group I haptophytes from freshwater ecosystems. Paleolake Olduvai represents the first reported occurrence of alkenones in a low-latitude Pleistocene lake, where the absence of alkatetraenones may reflect contributions from strains of Group II haptophytes that are favored by warmer temperatures or saline conditions. Temporal variations in unsaturation indices (U37K', U38K') and the proportions of alken-2-ones and alken-3-ones likely reflect influences on alkenone production by haptophytes that are associated with changes in the lake environment primarily driven by hydrologic cycles (e.g., salinity and alkalinity) rather than lake temperatures.

The efficacy of high-load resistance training in combination with aerobic training in patients with coronary artery disease: a dose-dependent randomised, controlled clinical trial

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Slovenian Research Agency Background The combination of resistance training (RT) and aerobic training (AT) was shown to be superior compared to AT, although most studies applied only low-loads (LL) to moderate-loads in RT. Therefore, it remains to be elucidated whether high-load (HL) RT elicits greater improvement in maximal aerobic capacity and maximal muscle strength compared to low-load (LL) RT in combination to AT in patients with coronary artery disease (CAD). Purpose The aim of our study was to investigate the effects of HL-RT and LL-RT combined with AT in comparison to AT on maximal aerobic capacity, muscle strength and health-related quality of life. Methods We randomised 79 patients with CAD to HL-RT+AT (70 %-80% of one repetition maximum [1-RM]), LL-RT+AT (35%-40% of 1-RM) or AT group and 59 patients with mean (SD) age 61 (8) years and left ventricular ejection fraction 53 (9) % completed 12 weeks (36 training sessions) of the study. After the initial ambulatory screening by cardiologist and cardiopulmonary exercise test, patients were familiarised with proper lifting and breathing technique, and performed 1-RM test on leg press machine. During the training, the RT load progressively increased from 70% of 1-RM (6–11 repetitions per set) to 80% of 1-RM (6–8 reps per set) in HL-RT group and from 35% of 1-RM (12–22 reps per set) to 40% of 1-RM (12–16 reps per set) in LL-RT group in the first seven weeks of the intervention. Following re-evaluation of 1-RM, the training load in HL-RT group was progressed from 70% 1-RM (11 reps per set) to 80% 1-RM (6–8 reps per set), and the load in LL-RT group was progressed from 35% 1-RM (22 reps per set) to 40% 1-RM (12–16 reps per set). All patients performed AT consisted of 3-5 min of work-load interval cycling separated by 2 min of unloaded cycling progressing from 50% to 80% maximal workload achieved at baseline cardiopulmonary exercise test. We measured maximal aerobic capacity (VO2 max), maximal voluntary contraction (MVC) and quality of life at baseline and post-training. Results Exercise training was safe and associated with improvement in VO2 max (p &amp;lt; 0.01) in all training groups, whereas only LL-RT and HL-RT group improved MVC (both p &amp;lt; 0.001). Following training, VO2 max increased more in HL-RT group compared to AT group (+18 %, p = 0.032), and MVC increased more in HL-RT group compared to LL-RT group (+7 %, p = 0.018) and AT group (+16 %, p &amp;lt; 0.001). HL-RT group improved mental functioning component of short form 12-item quality of life questionnaire (+6 points, p = 0.003), with no significant difference compared to other training modalities. Conclusions RT on top of routine CR management, is safe and efficacious training modality for patients with CAD enrolled in cardiac rehabilitation.

Concurrent Training Programming: The Acute Effects of Sprint Interval Exercise on the Subsequent Strength Training.

Exercise modality has been proposed to reduce the interferences between aerobic and resistance sessions during concurrent training. The aim of the study was to examine the acute effects of cycling or running sprint interval exercise on subsequent resistance training sessions. Twenty-five competitive male rugby union players were recruited. Players were tested during three conditions: CONTROL (resistance training session only), CYCLE and RUN (corresponding to a concurrent training scheme with cycling or running sprint interval exercise conducted on the morning, followed by a resistance training session). Four hours rest was proposed between the aerobic and resistance training session. Muscle performance (bar velocity during bench press and box squat, counter movement jump height) and subjective ratings (rate of perceived exertion, wellbeing) were assessed during and after aerobic or resistance training sessions. No significant difference was observed for muscle performance (vertical jump height and bar velocity). However, significant higher perceived exertion and low-value scaled subjective wellbeing were observed in RUN (7.7 ± 1.1 and 17.9 ± 4.1, respectively) as compared with the two other conditions (6.7 ± 1.5 and 21.1 ± 3.6 for CONTROL and 7.4 ± 1.1 and 20.1 ± 3.9 for CYCLE). It was concluded that the exercise modality (running or cycling) during the aerobic exercise using a sprint interval exercise did not impact the quality of the resistance session. However, subjective ratings were affected the following days. Cycling exercises might be more adequate when performing a sprint interval training session during concurrent training programs.

Validity of the Favero Assioma Duo Power Pedal System in Maximal-Effort Cycling Tests.

The pedal-based power meter has its advantages, so it has become a popular monitoring tool in cycling. This study aimed to examine the validity of the Favero Assioma Duo power pedal system (FAD) in comparison with the SRM, which is considered the gold standard under maximal-effort cycling conditions, and a widely used cycling test, the 20-minute Functional Threshold Test. Fourteen male adolescent cyclists completed a series of cycling intervals including 5, 15, 30, 60, 240, 600, and 1200 seconds (20-min Functional Threshold Test) with their maximal-effort performance on 2 separate days. Power output data were collected from the FAD and the SRM for analysis. Extremely strong correlations and excellent intraclass correlation coefficients (ICCs) were found between the power output values registered with the FAD and the SRM overall (r > .999, ICC = .996) and each power test (r > .98, ICC > .91). A low bias was found in power tests of longer durations (-3.2% at 240-s test, -3.3% at 600-s test, and -3.1% at 20-min Functional Threshold Test), while the bias augmented in shorter intervals (-2.7% at 5-s test, -3.6% at 15-s test, and -2.6% at 30-s test and -3.3% at 60-s test). A regression equation was proposed as y = -2.943 + 0.976x to diminish the bias (-0.2W) with increased r value (>.98) and ICC (>.98). The FAD appears to be a valid tool for the measures of maximal-effort performance. The recorded power value reflects the true value with proposed regression equation.

Blood flow restriction during self-paced aerobic intervals reduces mechanical and cardiovascular demands without modifying neuromuscular fatigue

ABSTRACT This study examined cardiovascular, perceptual and neuromuscular fatigue characteristics during and after cycling intervals with and without blood flow restriction (BFR). Fourteen endurance cyclists/triathletes completed four 4-minute self-paced aerobic cycling intervals at the highest sustainable intensity, with and without intermittent BFR (60% of arterial occlusion pressure). Rest interval durations were six, four and four minutes, respectively. Power output, cardiovascular demands and ratings of perceived exertion (RPE) were averaged over each interval. Knee extension torque and vastus lateralis electromyography responses following electrical stimulation of the femoral nerve were recorded pre-exercise, post-interval one (+1, 2 and 4-minutes) and post-interval four (+1, 2, 4, 6 and 8-minutes). Power output during BFR intervals was lower than non-BFR (233 ± 54 vs 282 ± 60 W, p < 0.001). Oxygen uptake and heart rate during BFR intervals were lower compared to non-BFR (38.7 ± 4.5 vs 44.7 ± 6.44 mL kg−1 min−1, p < 0.001; 160 ± 14 vs 166 ± 10 bpm, p < 0.001), while RPE was not different between conditions. Compared to pre-exercise, maximal voluntary contraction torque and peak twitch torque were reduced after the first interval with further reductions following the fourth interval (p < 0.001) independent of condition (p = 0.992). Voluntary activation (twitch interpolation) did not change between timepoints (p = 0.375). Overall, intermittent BFR reduced the mechanical and cardiovascular demands of self-paced intervals without modifying RPE or knee-extensor neuromuscular characteristics. Therefore, BFR reduced the cardiovascular demands while maintaining the muscular demands associated with self-paced intervals. Self-paced BFR intervals could be used to prevent cardiovascular and perceptual demands being the limiting factor of exercise intensity, thus allowing greater physiological muscular demands compared to intervals without BFR. Highlights The use of blood flow restriction (BFR) during self-paced intervals (at the highest perceived sustainable intensity) causes a reduction in power output, pulmonary oxygen uptake and heart rate compared with non-restricted self-paced intervals. Despite lower mechanical and physiological demands during BFR cycling, the magnitude and aetiology of neuromuscular fatigue were not different to intervals without BFR, indicating the internal muscular load during BFR was elevated and potentially equivalent compared to without BFR. Self-paced intervals could be a suitable model to prescribe aerobic BFR exercise as an adjunct training stimulus for endurance cyclists.

Remote and in-Situ Characterization of Mars Analogs: Coupling Scales to Improve the Search for Microbial Signatures on Mars

Past environments on Mars contained abundant water, suggesting certain regions may have been conducive to life as we know it and implying the potential for microbial inhabitants. Gale and Jezero craters, home of the Perseverance and Curiosity rovers, hosted ancient lakes that experienced periods of active hydrologic cycling and prolonged drying intervals. Exploration of these basins (and future operations on Mars) will benefit from detailed characterizations of analogous environments on Earth, where life detection strategies at various spatial scales (i.e., rover to orbiter) can be tested and validated. Investigations of terrestrial analogs are critical for understanding (1) how microorganisms generate chemical biosignatures in environments characterized by multiple extreme conditions; (2) the impact of environmental conditions and mineralogy on biosignature preservation; and (3) what technologies and techniques are needed to detect biosignatures remotely or in situ. Here, we survey five terrestrial sites analogous to climate conditions proposed for Late Noachian to Early Hesperian Mars, when craters are thought to have hosted active lakes. We review the geologic setting, environmental conditions, microbial habitability, extant microbial communities, and preserved biomarkers at each analog and discuss their relevance to the search for signs of life in Martian craters with in situ and remote instrumentation. The analogs range from active to desiccated lake systems, temperate to hyper-arid climates, and have acidic to neutral-pH and hypo- to hyper-saline waters. Each analog hosts microorganisms adapted to multiple extremes (polyextremophiles), including aspects of water availability (i.e., surface waters versus shallow subsurface water versus groundwater) and physiochemistry (e.g., water activity, salinity, temperature, alkalinity, pH, and redox potential) that can form macrobiological features such as microbial mats. Comparing the expected achievable spatial resolution of several key Mars instruments to the spatial extent of macrobiological features at each analog reveals that most features are unlikely to be resolved from orbit and require rover-scale instruments for detection. We recommend that future studies at these analogs use multi-scale remote sensing surveys to determine thresholds for detecting macrobiological features and map how patterns in mineralogy or physical characteristics of environments correlate to modern-day microbial communities or preserved biomarkers. It will also be critical to determine how the characteristics of macrobiological features, such as areal extent, percent cover, thickness, pigments, etc., impact detectability thresholds. These findings can provide vital information on potential topographic or spectroscopic signatures of life, and at what scales they are detectable. This research is critical to guide sample collection locations within craters like Jezero, and for selecting landing sites for future missions in evaporative Martian basins and other rocky bodies.

An experimental damage tolerance investigation of CFRP composites on a substructural level

The damage tolerance (DT) allowables for the design of a composite structure are typically determined through experiments on the coupon level. The present study examines the transferability of the DT behavior from the coupon level to a structural level. For that purpose, a DT critical panel with two stiffeners was designed and tested. In one quasi-static and two cyclic compression after impact tests, the damage evolution behavior was studied and compared with results achieved on the coupon level. Similar phenomena were found on both scales: a long interval of load cycles, without any detectable damage evolution is succeeded by the sudden propagation of the delamination and the fiber fracture. Afterward, the ultimate failure occurs within few load cycles. Even though the stiffened panel offers a significant possibility to transfer load from the damaged skin, a significant damage stabilization could not be achieved. The no-growth interval was found to be shorter on the structural scale, however, an analytical DT analysis suggests the different damage size as the most likely cause. However, it was found that the stiffeners slow down the damage propagation. Eventually, the study confirms the no-growth design approach as the preferred method to account for the DT of stiffened, compression-loaded composite structures.

Potential use of matakaolin as a partial replacement of preformulated lime binder to improve durability of hemp concrete under cyclic wetting/drying aging

This study reports the experimental investigation of a commercial formulated lime binder (Tadical PF70) modification effect on the durability of hemp concrete specimens when subjected to continuous wetting and drying cycles. The influence of partial replacement of Tradical PF70 binder by metakaolin has been studied by testing the physico-mechanical properties of samples including mass loss, porosity, compressive and flexural strengths, and corresponding toughness for aging conditions of 15, 25, and 50 wetting/drying cycles. Considered as a critical factor which contributes to the specimen deterioration, a separate investigation of the degradation rate of the embedded hemp particles in specimens at aging cycle intervals has been also performed. The results have shown that the pozzolanic reaction of amorphous silica contained in metakaolin with dissolved calcium hydroxide appears to significantly minimise the degradation of hemp concrete. The corresponding reaction consumes calcium hydroxide to produce hydrated calcium silicates and in turn will lead to the lowest alkalinity of pore solution which is considered as the main responsible for hydrolysis of hemp particles. The examination of the relationship between embedded hemp particle deterioration degree and the loss of mechanical properties of hemp concrete has shown that the use of metakaolin is an effective means to improve durability of specimens mainly through the restraint of hemp particle degradation.

Exercise Effects on Motor Skill Consolidation and Intermuscular Coherence Depend on Practice Schedule.

Cardiorespiratory or aerobic exercise immediately after practice of an upper-extremity motor skill task can facilitate skill consolidation, as demonstrated by enhanced performances at 24 h and 7-day retention tests. The purpose of this study was to examine the effect of acute cardiorespiratory exercise on motor skill consolidation when skill practice involved low and high levels of contextual interference introduced through repetitive and interleaved practice schedules, respectively. Forty-eight young healthy adults were allocated to one of four groups who performed either repetitive or interleaved practice of a pinch grip motor sequence task, followed by either a period of seated rest or a bout of high-intensity interval cycling. At pre- and post-practice and 24 h and 7-day retention tests, we assessed motor skill performance and β-band (15–35 Hz) intermuscular coherence using surface electromyography (EMG) collected from the abductor pollicis brevis and first dorsal interosseous. At the 7-day retention test, off-line consolidation was enhanced in the cardiorespiratory exercise relative to the rest group, but only among individuals who performed interleaved motor skill practice (p = 0.02). Similarly, at the 7-day retention test, β-band intermuscular coherence increased to a greater extent in the exercise group than in the rest group for those who performed interleaved practice (p = 0.02). Under the present experimental conditions, cardiorespiratory exercise preferentially supported motor skill consolidation and change in intermuscular coherence when motor skill practice involved higher rather than lower levels of contextual interference.

Comparisons Between Normobaric Normoxic and Hypoxic Recovery on Post-exercise Hemodynamics After Sprint Interval Cycling in Hypoxia.

The aim of this study was to investigate the effects of either normoxic or hypoxic recovery condition on post-exercise hemodynamics after sprint interval leg cycling exercise rather than hemodynamics during exercise. The participants performed five sets of leg cycling with a maximal effort (30 s exercise for each set) with a 4-min recovery of unloaded cycling between the sets in hypoxia [fraction of inspired oxygen (FiO2) = 0.145]. The load during pedaling corresponded to 7.5% of the individual’s body weight at the first set, and it gradually reduced from 6.5 to 5.5%, 4.5, and 3.5% for the second to fifth sets. After exercise, the participants rested in a sitting position for 30 min under normoxia (room-air) or hypoxia. Mean arterial pressure decreased over time during recovery (p < 0.001) with no condition and interaction effects (p > 0.05). Compared to pre-exercise values, at 30 min after exercise, mean arterial pressure decreased by 5.6 ± 4.8 mmHg (mean ± standard deviation) during hypoxic recovery, and by 5.3 ± 4.6 mmHg during normoxic recovery. Peripheral arterial oxygen saturation (SpO2) at all time points (5, 10, 20, and 30 min) during hypoxic recovery was lower than during normoxic recovery (all p < 0.05). The area under the hyperemic curve of tissue oxygen saturation (StO2) at vastus lateralis defined as reperfusion curve above the baseline values during hypoxic recovery was lower than during normoxic recovery (p < 0.05). Collectively, post-exercise hypotension after sprint interval leg cycling exercise was not affected by either normoxic or hypoxic recovery despite marked differences in SpO2 and StO2 during recovery between the two conditions.

Characteristic Scales of Tropical Convection Based on the Japanese Advanced Himawari-8 Imager Observations

Convective activities play an important role in tropical weather systems. To investigate the characteristic scales of convection, a method combining a principal component (PC) analysis with Fourier decomposition is applied to brightness temperature observations from Advanced Himawari-8 Imager (AHI). Characteristic scales of different modes in tropical convective systems are obtained. The explained variance reduces rapidly from the first to the 60th PC mode by two magnitudes; the horizontal scale decreases from over 2000 km to about 100 km, and the timescale changes from more than 4 days to around 5 h. By a detailed comparison of the first, 20th, 40th, and 60th PC modes, it is found that large-scale (over 2000 km in wavelength) convective activities usually have significant nocturnal enhancement, whereas meso-scale (about 100 km in wavelength) convective activities feature short period and fast change with more intense development in regions of active large-scale convection. This study may be of some importance for the choice of AHI data assimilation cycling interval, the horizontal resolution as well as data thinning for geostationary satellite observations.

In vivo and ex vivo electrophysiological study of the mouse heart to characterize the cardiac conduction system, including atrial and ventricular vulnerability.

The mouse is a common and cost-effective animal model for basic research, and the number of genetically engineered mouse models with cardiac phenotype is increasing. In vivo electrophysiological study in mice is similar to that performed in humans. It is indispensable for acquiring intracardiac electrocardiogram recordings and determining baseline cardiac cycle intervals. Furthermore, the use of programmed electrical stimulation enables determination of parameters such as sinoatrial conduction time, sinus node recovery time, atrioventricular-nodal conduction properties, Wenckebach periodicity, refractory periods and arrhythmia vulnerability. This protocol describes specific procedures for determining these parameters that were adapted from analogous human protocols for use in mice. We include details of ex vivo electrophysiological study, which provides detailed insights into intrinsic cardiac electrophysiology without external influences from humoral and neural factors. In addition, we describe a heart preparation with intact innervation by the vagus nerve that can be used as an ex vivo model for vagal control of the cardiac conduction system. Data acquisition for in vivo and ex vivo electrophysiological study takes ~1 h per mouse, depending on the number of stimulation protocols applied during the procedure. The technique yields highly reliable results and can be used for phenotyping of cardiac disease models, elucidating disease mechanisms and confirming functional improvements in gene therapy approaches as well as for drug and toxicity testing.

Efficacy and Safety of IncobotulinumtoxinA in the Treatment of Lower Limb Spasticity in Japanese Subjects.

ObjectiveTo confirm the efficacy and safety of incobotulinumtoxinA (Xeomin®, Merz Pharmaceuticals GmbH; total dose 400 U) in Japanese subjects with lower limb (LL) poststroke spasticity using the Modified Ashworth Scale spasticity score for the plantar flexors (MAS-PF).MethodsThis phase III study (Japic clinical study database No. CTI-153030, 7 October 2015) included a double-blind, 12-week main period (MP) in which 208 subjects were randomized to receive one injection cycle of incobotulinumtoxinA 400 U (n = 104) or placebo (n = 104) in the pes equinus muscles, and an open-label extension (OLEX) that enrolled 202 subjects who received three injection cycles, 10–14 weeks in duration (the last cycle was fixed at 12 weeks). Changes in MAS-PF for incobotulinumtoxinA vs. placebo from baseline to Week 4 of the MP and to the end-of-cycle visits in the OLEX were evaluated.ResultsThe area under the curve for the change in MAS-PF was statistically significantly greater with incobotulinumtoxinA vs. placebo in the MP (mean: −7.74 vs. −4.76; least squares mean: −8.40 vs. −5.81 [p = 0.0041]). In the OLEX, mean changes in MAS-PF from baseline to end-of-study showed continued improvement with repeated injections. No new safety concerns were observed with the incobotulinumtoxinA treatment. Its efficacy and safety were consistent regardless of the length of the injection cycle interval in the OLEX.ConclusionThis study demonstrated that incobotulinumtoxinA (total dose 400 U) is an effective and a well-tolerated treatment for LL spasticity in Japanese subjects using flexible injection intervals of 10–14 weeks.

Acute Effects of High-Intensity Aerobic Exercise on Motor Cortical Excitability and Inhibition in Sedentary Adults.

Transcranial magnetic stimulation studies have demonstrated increased cortical facilitation and reduced inhibition following aerobic exercise, even when examining motor regions separate to the exercised muscle group. These changes in brain physiology following exercise may create favorable conditions for adaptive plasticity and motor learning. One candidate mechanism behind these benefits is the increase in brain-derived neurotropic factor (BDNF) observed following exercise, which can be quantified from a venous blood draw. The aim of this study was to investigate changes in motor cortex excitability and inhibition of the upper limb, and circulating BDNF, following high-intensity interval training (HIIT) on a stationary bicycle. Nineteen sedentary adults participated in a randomized crossover design study involving a single bout of high-intensity interval cycling for 20 min or seated rest. Venous blood samples were collected, and transcranial magnetic stimulation (TMS) was used to stimulate the extensor carpi radialis (ECR), where motor evoked potentials (MEP) were recorded pre- and post-condition. Following exercise, there was a significant increase (29.1%, p < 0.001) in corticospinal excitability measured at 120% of resting motor threshold (RMT) and a reduction in short-interval cortical inhibition (SICI quantified as 86.2% increase in the SICI ratio, p = 0.002). There was a non-significant (p = 0.125) 23.6% increase in BDNF levels. Collectively, these results reflect a net reduction in gamma aminobutyric acid (GABA)ergic synaptic transmission and increased glutamatergic facilitation, resulting in increased corticospinal excitability. This study supports the notion that acute high-intensity exercise provides a potent stimulus for inducing cortical neuroplasticity, which may support enhanced motor learning.