This study aimed to investigate the effects of performing either eccentric-only (ECC) or eccentric-concentric (ECC-CON) back squats (BS) with a supramaximal load on countermovement jump (CMJ) performance. Changes in front thigh skin surface temperature and mechanical properties (oscillation frequency and stiffness) of the vastus lateralis were also examined. Fourteen male powerlifters participated in this study (age: 22.5 ± 2.3 years, body weight: 84.2 ± 11.1 kg, height: 178 ± 7 cm, training experience: 5.4 ± 1.6 years, BS one-repetition maximum [1RM]: 177 ± 22.8 kg). The experimental sessions included 2 sets of 2 BS at 110% 1RM of either ECC-CON (load distributed by half on the barbell [55%] and on weight releasers [55%]) or ECC (only eccentric phase of BS) and CTRL with no CA applied. CMJ performance, mechanical properties, and skin surface temperature were measured before and at the third, sixth, ninth, and 12th min. After each protocol, only the ECC-CON condition led to a significant increase in CMJ height after individual optimal rest time compared to pre-CA (38.1 ± 5.2 vs. 39.8 ± 5.0 cm; p = 0.003; effect size [ES] = 0.32; Δ = 4.9 ± 5.0%) with a significant rise in skin surface temperature (32.98 ± 1.24 vs. 33.69 ± 0.96°C; p = 0.006; ES = 0.62; Δ = 2.2 ± 2.6%) and no significant changes in mechanical properties of the vastus lateralis. The ECC-CON condition led to a significant acute improvement in CMJ height and an increase in front thigh skin surface temperature among powerlifters. The ECC-CON supramaximal lower limb PAPE protocol should be effectively used among males representing high levels of lower limb muscle strength (>2 × body mass).

• MeSH
• Biomechanical Phenomena MeSH
• Quadriceps Muscle physiology   MeSH
• Adult MeSH
• Muscle, Skeletal physiology   MeSH
• Humans MeSH
• Young Adult MeSH
• Resistance Training MeSH
• Athletic Performance * physiology   MeSH
• Thigh physiology   MeSH
• Muscle Strength physiology   MeSH
• Skin Temperature * physiology   MeSH
• Weight Lifting * physiology   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: The human skin is greatly affected by external factors such as UV radiation (UVR), ambient temperature (T), and air humidity. These factors oscillate during the year giving rise to the seasonal variations in the skin properties. The aim of this study was to evaluate the effect of seasons, environmental T, relative and absolute humidity on the skin parameters of Caucasian women, perform a literature review and discuss the possible factors lying behind the found changes. MATERIALS AND METHODS: We measured stratum corneum (SC) hydration, transepidermal water loss (TEWL), sebum level, erythema index, and elasticity parameters R2 and R7 on the forehead and the cheek of Caucasian women from the Czech Republic throughout the year. We also performed a non-systematic literature review focused on the seasonal variations in these skin parameters. RESULTS: We confirmed a well-documented low SC hydration and sebum production in winter. In spring, we found the lowest TEWL (on the forehead) and the highest SC hydration but also the highest erythema index and the lowest elasticity presumably indicating skin photodamage. For most of the skin parameters, the seasonal variations probably arise due to a complex action of different factors as we extensively discussed. CONCLUSION: The data about the seasonal variations in the skin parameters are still highly inconsistent and further studies are needed for better understanding of the normal skin changes throughout the year.

• MeSH
• Skin Physiological Phenomena * MeSH
• Skin * metabolism   MeSH
• Humans MeSH
• Water Loss, Insensible MeSH
• Seasons MeSH
• Sebum MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

The sudden interruption of recurring larch budmoth (LBM; Zeiraphera diniana or griseana Gn.) outbreaks across the European Alps after 1982 was surprising, because populations had regularly oscillated every 8-9 years for the past 1200 years or more. Although ecophysiological evidence was limited and underlying processes remained uncertain, climate change has been indicated as a possible driver of this disruption. An unexpected, recent return of LBM population peaks in 2017 and 2018 provides insight into this insect's climate sensitivity. Here, we combine meteorological and dendrochronological data to explore the influence of temperature variation and atmospheric circulation on cyclic LBM outbreaks since the early 1950s. Anomalous cold European winters, associated with a persistent negative phase of the North Atlantic Oscillation, coincide with four consecutive epidemics between 1953 and 1982, and any of three warming-induced mechanisms could explain the system's failure thereafter: (1) high egg mortality, (2) asynchrony between egg hatch and foliage growth, and (3) upward shifts of outbreak epicentres. In demonstrating that LBM populations continued to oscillate every 8-9 years at sub-outbreak levels, this study emphasizes the relevance of winter temperatures on trophic interactions between insects and their host trees, as well as the importance of separating natural from anthropogenic climate forcing on population behaviour.

• MeSH
• Disease Outbreaks MeSH
• Climate Change MeSH
• Larix * MeSH
• Moths * MeSH
• Population Dynamics MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

Explaining why fluctuations in abundances of spatially disjunct populations often are correlated through time is a major goal of population ecologists. We address two hypotheses receiving little to no testing in wild populations: (i) that population cycling facilitates synchronization given weak coupling among populations, and (ii) that the ability of periodic external forces to synchronize oscillating populations is a function of the mismatch in timescales (detuning) between the force and the population. Here, we apply new analytical methods to field survey data on gypsy moth outbreaks. We report that at timescales associated with gypsy moth outbreaks, spatial synchrony increased with population periodicity via phase locking. The extent to which synchrony in temperature and precipitation influenced population synchrony was associated with the degree of mismatch in dominant timescales of oscillation. Our study provides new empirical methods and rare empirical evidence that population cycling and low detuning can promote population spatial synchrony.

• MeSH
• Models, Biological MeSH
• Time Factors MeSH
• Rain * MeSH
• Larva growth & development   physiology   MeSH
• Moths growth & development   physiology   MeSH
• Population Dynamics MeSH
• Temperature * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geographicals
• United States MeSH

BACKGROUND: A water-impermeable testa acts as a barrier to a seed's imbibition, thereby imposing dormancy. The physical and functional properties of the macrosclereids are thought to be critical determinants of dormancy; however, the mechanisms underlying the maintenance of and release from dormancy in pea are not well understood. METHODS: Seeds of six pea accessions of contrasting dormancy type were tested for their ability to imbibe and the permeability of their testa was evaluated. Release from dormancy was monitored following temperature oscillation, lipid removal and drying. Histochemical and microscopic approaches were used to characterize the structure of the testa. KEY RESULTS: The strophiole was identified as representing the major site for the entry of water into non-dormant seeds, while water entry into dormant seeds was distributed rather than localized. The major barrier for water uptake in dormant seeds was the upper section of the macrosclereids, referred to as the 'light line'. Dormancy could be released by thermocycling, dehydration or chloroform treatment. Assays based on either periodic acid or ruthenium red were used to visualize penetration through the testa. Lipids were detected within a subcuticular waxy layer in both dormant and non-dormant seeds. The waxy layer and the light line both formed at the same time as the establishment of secondary cell walls at the tip of the macrosclereids. CONCLUSIONS: The light line was identified as the major barrier to water penetration in dormant seeds. Its outer border abuts a waxy subcuticular layer, which is consistent with the suggestion that the light line represents the interface between two distinct environments - the waxy subcuticular layer and the cellulose-rich secondary cell wall. The mechanistic basis of dormancy break includes changes in the testa's lipid layer, along with the mechanical disruption induced by oscillation in temperature and by a decreased moisture content of the embryo.

• MeSH
• Pisum sativum * MeSH
• Germination * MeSH
• Seeds MeSH
• Temperature MeSH
• Plant Dormancy MeSH
• Water MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (δ18O, δ13C) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (δ18Osw) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (δ18Osw), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low δ18Osw) versus Mediterranean (high δ18Osw) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front.

• MeSH
• Geologic Sediments analysis   MeSH
• Oxygen Isotopes analysis   MeSH
• Climate Change * MeSH
• Radiometric Dating * MeSH
• Trees physiology   MeSH
• Temperature MeSH
• Fossils * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Mediterranean Region MeSH

This study extends our previous work by examining the effects of alpha2-adrenoceptors under cold stimulation involving the increase of myogenic vascular oscillations as increases of very-low-frequency and low-frequency of the blood pressure variability. Forty-eight adult male Sprague-Dawley rats were randomly divided into four groups: vehicle; yohimbine; hexamethonium+yohimbine; guanethidine+yohimbine. Systolic blood pressure, heart rate, power spectral analysis of spontaneous blood pressure and heart rate variability and spectral coherence at very-low-frequency (0.02 to 0.2 Hz), low-frequency (0.2 to 0.6 Hz), and high-frequency (0.6 to 3.0 Hz) regions were monitored using telemetry. Key findings are as follows: 1) Cooling-induced pressor response was attenuated by yohimbine and further attenuated by hexamethonium+yohimbine and guanethidine+yohimbine, 2) Cooling-induced tachycardia response of yohimbine was attenuated by hexamethonium+yohimbine and guanethidine+yohimbine, 3) Different patterns of power spectrum reaction and coherence value compared hexamethonium+yohimbine and guanethidine+yohimbine to yohimbine alone under cold stimulation. The results suggest that sympathetic activation of the postsynaptic alpha2-adrenoceptors causes vasoconstriction and heightening myogenic vascular oscillations, in turn, may increase blood flow to prevent tissue damage under stressful cooling challenge.

• MeSH
• Adrenergic alpha-2 Receptor Antagonists pharmacology   MeSH
• Receptors, Adrenergic, alpha-2 physiology   MeSH
• Hemodynamics drug effects   physiology   MeSH
• Blood Pressure drug effects   physiology   MeSH
• Rats MeSH
• Random Allocation MeSH
• Cold Temperature adverse effects   MeSH
• Rats, Sprague-Dawley MeSH
• Heart Rate drug effects   physiology   MeSH
• Telemetry methods   MeSH
• Vasoconstriction drug effects   physiology   MeSH
• Yohimbine pharmacology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

The onset of flowering in 78 wild and domesticated terrestrial plant species recorded in South Moravia (Czech Republic) from 1965 to 2014 was correlated with the North Atlantic Oscillation (NAO) index of the preceding winter. Flowering occurred significantly earlier following positive winter NAO phases (causing spring to be warmer than normal in Central Europe) in nearly all early-flowering (March, April) species; high Pearson correlation values were recorded in, e.g., goat willow, spring snowflake, golden bell, cornelian cherry, sweet violet, cherry plum, grape hyacinth, apricot, blackthorn, common dandelion, cherry, southern magnolia, common apple, cuckoo flower, European bird cherry, and cherry laurel. In contrast, the timing of later-flowering plant species (May to July) did not correlate significantly with the winter NAO index. It was found that local temperature is obviously a proximate factor of plant phenology, while the winter NAO is the ultimate factor, affecting temperature and other meteorological phenomena in Central Europe during spring season.

• MeSH
• Atmospheric Pressure MeSH
• Flowers growth & development   MeSH
• Magnoliopsida growth & development   MeSH
• Weather MeSH
• Seasons MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Atlantic Ocean MeSH
• Czech Republic MeSH

For every eukaryotic cell to grow and divide, intricately coordinated action of numerous proteins is required to ensure proper cell-cycle progression. The fission yeast Schizosaccharomyces pombe has been instrumental in elucidating the fundamental principles of cell-cycle control. Mutations in S. pombe 'cut' (cell untimely torn) genes cause failed coordination between cell and nuclear division, resulting in catastrophic mitosis. Deletion of cbf11, a fission yeast CSL transcription factor gene, triggers a 'cut' phenotype, but the precise role of Cbf11 in promoting mitotic fidelity is not known. We report that Cbf11 directly activates the transcription of the acetyl-coenzyme A carboxylase gene cut6, and the biotin uptake/biosynthesis genes vht1 and bio2, with the former 2 implicated in mitotic fidelity. Cbf11 binds to a canonical, metazoan-like CSL response element (GTGGGAA) in the cut6 promoter. Expression of Cbf11 target genes shows apparent oscillations during the cell cycle using temperature-sensitive cdc25-22 and cdc10-M17 block-release experiments, but not with other synchronization methods. The penetrance of catastrophic mitosis in cbf11 and cut6 mutants is nutrient-dependent. We also show that drastic decrease in biotin availability arrests cell proliferation but does not cause mitotic defects. Taken together, our results raise the possibility that CSL proteins play conserved roles in regulating cell-cycle progression, and they could guide experiments into mitotic CSL functions in mammals.

• MeSH
• Biotin metabolism   MeSH
• DNA, Fungal metabolism   MeSH
• Epistasis, Genetic MeSH
• Transcription, Genetic MeSH
• Genes, Fungal * MeSH
• Mitosis genetics   MeSH
• Mutation genetics   MeSH
• Promoter Regions, Genetic MeSH
• Gene Expression Regulation, Fungal * MeSH
• Schizosaccharomyces pombe Proteins genetics   metabolism   MeSH
• Schizosaccharomyces cytology   genetics   MeSH
• Protein Binding genetics   MeSH
• Publication type
• Journal Article MeSH

AIM: We analysed the effects of acute temperature change on the beating rate, conduction properties and calcium transients in the chick embryonic heart in vitro and in ovo. METHODS: The effects of temperature change (34, 37 and 40 °C) on calcium dynamics in isolated ED4 chick hearts in vitro were investigated by high-speed calcium optical imaging. For comparison and validation of in vitro measurements, experiments were also performed in ovo using videomicroscopy. Artificial stimulation experiments were performed in vitro and in ovo to uncover conduction limits of heart segments. RESULTS: Decrease in temperature from 37 to 34 °C in vitro led to a 22% drop in heart rate and unchanged amplitude of Ca(2+) transients, compared to a 25% heart rate decrease in ovo. Increase in temperature from 37 to 40 °C in vitro and in ovo led to 20 and 23% increases in heart rate, respectively, and a significant decrease in amplitude of Ca(2+) transients (atrium -35%, ventricle -38%). We observed a wide spectrum of arrhythmias in vitro, of which the most common was atrioventricular (AV) block (57%). There was variability of AV block locations. Pacing experiments in vitro and in ovo suggested that the AV blocks were likely caused by relative tissue hypoxia and not by the tachycardia itself. CONCLUSION: The pacemaker and AV canal are the most temperature-sensitive segments of the embryonic heart. We suggest that the critical point for conduction is the connection of the ventricular trabecular network to the AV canal.

• MeSH
• Atrioventricular Block physiopathology   MeSH
• Electric Stimulation MeSH
• Cardiac Imaging Techniques MeSH
• Cardiac Pacing, Artificial MeSH
• Chick Embryo MeSH
• Myocardium metabolism   MeSH
• Heart Conduction System physiopathology   MeSH
• Heart diagnostic imaging   physiology   physiopathology   MeSH
• Arrhythmias, Cardiac physiopathology   MeSH
• Heart Rate physiology   MeSH
• Tachycardia physiopathology   MeSH
• Temperature * MeSH
• Calcium metabolism   MeSH
• Calcium Signaling physiology   MeSH
• Animals MeSH
• Check Tag
• Chick Embryo MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH