Large Increase In Volume Research Articles

A bimetallic sulfide Co9S8/MoS2/C heterojunction in a three-dimensional carbon structure for increasing sodium ion storage

The synthesis of high-rate and long-life anode materials for sodium ion batteries (SIBs) has attracted much attention. However, the slow kinetics and large increase in volume of the batteries remain major problems. Both metal-organic frameworks and MoS2 have shown properties suitable for SIBs, making research on their composite systems an attractive area of research. We report the formation of flower-like Co9S8/MoS2/C composites by a simultaneous vulcanization-carbonization process using MoCl5 as the Mo source and a 2-methylimidazole cobalt salt as the Co and C precursor at different temperatures (600, 700 and 800 °C) in sublimed sulfur. The effect of the heterojunction on the diffusion kinetics was analyzed using density functional theory. The results indicate that the electronic structure is different at the interface in the heterogeneous structure, exhibiting typical metallic properties and better electronic conductivity. In addition, the anode material Co9S8/MoS2/C synthesized at 700 °C had the most stable structure and best electrochemical performance of the three samples. Notably, the discharge capacity of Co9S8/MoS2/C-700 fully recovered from 368 to 571 mAh g−1 and then stabilized at 543 mAh g−1 when the current density was restored from 4000 to 40 mA g−1. This work demonstrates the preparation of heterojunction materials for composite anode materials as a step to producing high-performance metal SIBs.

P74: Plasma Osmolarity as a Determinant of Platelet Morphology and Function in Heart Failure

Purpose: Heart failure (HF) is associated with increased sodium and water retention, though disproportionately, leading to hypervolemia and reduced plasma osmolality (<275 mOsm/kg). HF is also associated with thrombosis/thromboembolic adverse advents, either in the native heart, or in mechanical circulatory support (MCS) devices implanted to restore hemodynamics. Platelets, critical cells in thrombosis, are mechanosensitive, responding to altered shear flow associated with HF or MCS devices. Excess plasma water and hypo-osmolarity can induce a gradient via which cells become swollen and stiff as water is forced into cells. It is recognized in cell biology that volume regulation and swelling can impact cell mechanics and function. However, it is not well understood how these processes are regulated or affect platelet function. Here, we investigate the affect of altered tonicity on platelet morphology/geometry and corresponding affect on platelet activation and aggregation. Methods: Human gel-filtered platelets (GFP; 20,000/µL) or platelet rich plasma (PRP; 100,000/µL) were obtained from fresh ACD-A anticoagulated whole blood. Modified Tyrode’s buffer osmolality was measured (Advanced Instruments; Osmo1), mixed with platelets and adjusted to a final concentration of either 250mOsm/kg (“Hypotonic”), 285mOsm/kg (“Isotonic”), or 325mOsm/kg (“Hypertonic”). Scanning ion conductance microscopy (SICM; Park Systems NX12) was utilized to quantify platelet morphology and volume. Platelet activation was measured as thrombin generation rate utilizing a previously-described modified prothrombinase assay. Platelet aggregation was quantified from agonist-mediated light-transmission aggregometry (BIO/DATA Corp; PAP-8E). All experiments were performed in duplicate with N ≥ 3 donors. Results: Overall, platelet geometry and function were altered in an osmolarity-dependent fashion. Hypotonic conditions led to an average 2.1µm3 (17.7%) increase in platelet volume, compared to isotonic conditions (Fig 1A). Despite this large increase in volume, there was a non-significant increase in thrombin generation rate in hypotonic conditions; however, a hypertonic environment led to a significant increase (0.14 min-1 average increase; Fig 1B). Collagen-mediated aggregation had a negative correlation to osmolarity, with significantly higher aggregation in hypotonic conditions (average 11.7% increase; Fig 1C). Conclusions: Hypotonicity leads to increased platelet volume and increased aggregability to collagen; however, platelet thrombin generation remains unaffected. The results of our study provide insight into operative mechanisms of thrombogenicity and altered platelet function under heart failure hypo-osmotic conditions. Further, these studies are hypothesis-generating as to the potential role of water, ion, and membrane mechanisms, providing the foundation for defining the impact of platelet volume regulation on shear-mediated platelet dysfunction in future studies.

Interaction Between Determinants Governing Urine Volume in Patients With ADPKD on Tolvaptan and its Impact on Quality of Life

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent genetic cause of kidney failure. Tolvaptan, a vasopressin 2 receptor antagonist, is the first drug with proven disease-modifying activity. Long-term treatment adherence is crucial, but a considerable fraction of patients discontinue treatment, because of aquaretic side effects. Twenty-four-hour urine was collected in 75 patients with ADPKD during up-titration of tolvaptan and, in combination with clinical characteristics, examined to identify factors influencing urine volume. Patient-reported outcomes were analyzed using the Short Form-12 (SF-12) and patient-reported outcomes questionnaires reporting micturition frequency and burden of urine volume. Initiation of therapy led to a large increase in urine volume followed by only minor further increase during up-dosing. Younger patients and patients with better kidney function experienced a larger relative rise. Twenty-four-hour urine osmolality dropped by about 50% after therapy initiation independently of dose, with a considerable proportion of patients achieving adequate suppression. Sodium and potassium intake turned out to be the only significant modifiable factors for urine volume after multivariate linear regression models, whereas age and weight could be identified as non-modifiable factors. No change in quality of life (QoL) was detected in relation to treatment or urine volume using SF-12 questionnaires, a finding that was further supported by the results of the patient-reported outcomes assessment. This study provides an in-detail analysis of factors associated with the degree of polyuria on tolvaptan and puts them into the context of QoL. These findings will contribute to optimized patient counseling regarding this treatment option in ADPKD.

Does variable RBE affect toxicity risks for mediastinal lymphoma patients? NTCP-based evaluation after proton therapy treatment

IntroductionMediastinal lymphoma (ML) is a solid malignancy affecting young patients. Modern combined treatments allow obtaining good survival probability, together with a long life expectancy, and therefore with the need to minimize treatment-related toxicities. We quantified the expected toxicity risk for different organs and endpoints in ML patients treated with intensity-modulated proton therapy (IMPT) at our centre, accounting also for uncertainties related to variable RBE. MethodsTreatment plans for ten ML patients were recalculated with a TOPAS-based Monte Carlo code, thus retrieving information on LET and allowing the estimation of variable RBE. Published NTCP models were adopted to calculate the toxicity risk for hypothyroidism, heart valve defects, coronary heart disease and lung fibrosis. NTCP was calculated assuming both constant (i.e. 1.1) and variable RBE. The uncertainty associated with individual radiosensitivity was estimated by random sampling α/β values before RBE evaluation. ResultsVariable RBE had a minor impact on hypothyroidism risk for 7 patients, while it led to significant increase for the remaining three (+24% risk maximum increase). Lung fibrosis was slightly affected by variable RBE, with a maximum increase of ≅ 1%. This was similar for heart valve dysfunction, with the exception of one patient showing an about 10% risk increase, which could be explained by means of large heart volume and D1 increase. DiscussionThe use of NTCP models allows for identifying those patients associated with a higher toxicity risk. For those patients, it might be worth including variable RBE in plan evaluation.

Zero-point motion of liquid and solid hydrogen

We present an inelastic neutron scattering study of liquid and solid hydrogen carried out using the wide Angular Range Chopper Spectrometer at Oak Ridge National Laboratory. From the observed dynamic structure factor, we obtained empirical estimates of the molecular mean-squared displacement and average translational kinetic energy. We find that the former quantity increases with temperature, indicating that a combination of thermal and quantum effects is important near the liquid-solid phase transition, contrary to previous measurements. We also find that the kinetic energy drops dramatically on melting of the crystals, a consequence of the large increase in molar volume together with the Heisenberg indeterminacy principle. Our results are compared with quantum Monte Carlo simulations based on different model potentials. In general, there is good agreement between our findings and theoretical predictions based on the Silvera-Goldman and Buck potentials.

Neuroanatomical and morphometric study of S100β positive astrocytes in the entorhinal cortex during ageing in the 3xTg-Alzehimer’s disease mouse model

Astrocytes contribute to the progression of neurodegenerative diseases, including Alzheimer’s disease (AD). Here, we report the neuroanatomical and morphometric analysis of astrocytes in the entorhinal cortex (EC) of the aged wild type (WT) and triple transgenic (3xTg-AD) mouse model of AD. Using 3D confocal microscopy, we determined the surface area and volume of positive astrocytic profiles in male mice (WT and 3xTg-AD) from 1 to 18 months of age. We showed that S100β-positive astrocytes were equally distributed throughout the entire EC in both animal types and showed no changes in Nv (number of cells/mm3) nor in their distribution at the different ages studied. These positive astrocytes, demonstrated an age-dependent gradual increase in their surface area and in their volume starting at 3 months of age, in both WT and 3xTg-AD mice. This last group demonstrated a large increase in both surface area and volume at 18 months of age when the burden of pathological hallmarks of AD is present (69.74% to 76.73% in the surface area and the volume, for WT and 3xTg-AD mice respectively). We observed that these changes were due to the enlargement of the cell processes and to less extend the somata. In fact, the volume of the cell body was increased by 35.82% in 18-month-old 3xTg-AD compared to WT. On the other hand, the increase on the astrocytic processes were detected as soon as 9 months of age where we found an increase of surface area and volume (36.56% and 43.73%, respectively) sustained till 18 month of age (93.6% and 113.78%, respectively) when compared age-matched non-Tg mice. Moreover, we demonstrated that these hypertrophic S100β-positive astrocytes were mainly associated with Aβ plaques. Our results show a severe atrophy in GFAP cytoskeleton in all cognitive areas; whilst within the EC astrocytes independent to this atrophy show no changes in GS and S100β; which can play a key role in the memory impairment.

Use of nanobubble water bioaugmented anaerobically digested sludge for high-efficacy energy production from high-solids anaerobic digestion of corn straw

An increasing attention has been paid to the secure and sustainable management of agricultural wastes, especially lignocellulosic biomass. Nanobubble water (NBW) contains 106–108 bubbles/mL with diameter <1000 nm. Although previous studies have examined the enhancement effects of NBW on methane production from organic solid wastes, the NBW-based anaerobic digestion (AD) system is still restrained from practical application due to the large increase in AD reactor volume, generation of wastewater, and increase in energy consumption as well. In this study, NBW bioaugmentation of anaerobically digested sludge for the first time was performed for high-solids AD of corn straw. Results show that cellulase, xylanases and lignin peroxidase activities were increased by 2–55% during the NBW bioaugmentation process. Significant enrichment of hydrolytic/acidogenic bacteria and methanogenic archaea were noticed in the NBW bioaugmented sludge. This study clearly demonstrated 47% increase in methane production from high-solids AD of corn straw when O2-NBW bioaugmented sludge was applied, achieving a net energy gain of 5138 MJ/t-volatile solids of corn straw with an energy recovery of 34%. The NBW-based high-solids AD system can provide a novel and sustainable management solution for renewable energy production from agricultural wastes, targeting the reduction of environmental pollution and energy crisis.

Inferior vena cava diameter adds information to pulmonary artery systolic pressure in outpatients with heart failure

Abstract Background Evaluation of pulmonary arterial pressure (PAP) is recommended by guidelines to diagnose and monitor congestion in patients with heart failure (HF). However, the high compliance of the venous system might buffer the effects of a large increase in intravascular volume and delay an elevation in PAP. Therefore, measuring inferior vena cava (IVC) diameter by ultrasounds might add important information in patients with HF, regardless of PAP. Aim To evaluate the relationship between the IVC diameter and systolic PAP (PAsP) assessed by echocardiography with mortality in outpatients with HF. Methods We enrolled consenting out-patients attending a community HF clinic for initial diagnosis or follow-up in Kingston upon Hull, UK between 2009–2012. HF was defined as the presence of relevant symptoms and signs and objective evidence of cardiac dysfunction: either a left ventricular systolic function (LVEF) &amp;lt;50% or elevated amino-terminal pro-brain natriuretic peptide (NT-proBNP) ≥125 pg/ml. IVC was considered dilated when &amp;gt;2.0 cm, PAsP elevated when &amp;gt;35 mmHg. Results Amongst the 874 patients enrolled, median age was 75 years, 68% were men, median LVEF was 44% and median NT-proBNP was 1125 pg/ml. 468 patients (54%) had normal IVC and PAsP, 117 (13%) had normal IVC but elevated PAsP, 75 (8%) had dilated IVC but normal PAsP and 214 (25%) had both dilated IVC and elevated PAsP. Compared to those with normal IVC and PAsP, those with elevated PAsP but normal IVC were older, more likely to be women, and had higher LVEF and NT-proBNP, whilst those with dilated IVC but normal PAsP had similar age and LVEF, but more signs of congestion and higher NT-proBNP. Compared to those with both normal IVC and PAsP (reference), those with dilated IVC but normal PAsP (HR: 1.83; CI: 1.04–3.25; P=0.037) or elevated PAsP but normal IVC (HR: 1.88; CI: 1.25–2.85; P=0.003) had a similarly increased risk of death but those with a dilated IVC and elevated PAsP had the greatest risk (HR: 4.16; CI: 3.10–5.57; P&amp;lt;0.001). Conclusion A dilated IVC is associated with mortality even when PAsP is not elevated. Tailoring treatments to reduce IVC diameter is a strategy worth exploring to improve outcomes in outpatients with heart failure. Funding Acknowledgement Type of funding sources: None.

In situ mechanochemical activation of reduced iron powder for arsenic stabilization in high content arsenic sulfide sludge

Arsenic sulfide slag (ASS) with high content of arsenic is a common industrial waste in nonferrous metal smelting. Because of the high potential of arsenic leaching under environmental conditions, it brings serious ecological threat during storage. Stabilization of the unstable arsenic in ASS is urgently needed for its safe disposal. Current stabilization methods such as hydrothermal treatment, stabilization/solidification, and thermal copolymerization still face challenges including high energy consumption, poor stabilize efficiency and large volume increase after treatment. Here we developed a mechanochemical strategy to stabilize the bleachable arsenic using reduced iron powder as stabilizer. The arsenic leaching concentration was decreased from 18484.9 mg /L to only 56.3 mg/L after treatment, achieving a stabilization efficiency of 99.7 %. The mechanism study proved that MC treatment triggered the corrosion of Fe powder and dissolution of As2O3 with the help of acidic water in the ASS. An integration of the rapid reduction and oxidation then happened for the soluble arsenic. The produced As(II) and As(V) reacted with sulfide and iron oxides, greatly reducing the arsenic leaching concentration. The BCR sequential extraction results further conformed most of the arsenics (83.7 %) in ASS were stabilization into the environmental stable residual fraction.

B, F Co-doping flexible carbon nanofibers as a fast and stable anode for potassium-ion hybrid capacitor

Potassium ion hybrid capacitors (PIHCs) have attracted widespread attention as combining the advantages of potassium ion batteries (PIBs) with supercapacitors. However, the sluggish kinetics caused by the large radius of K+ hinder the practical application of PIHCs. Herein, we synthesized a boron and fluorine co-doping interlaced network porous carbon nanofibers (BF-PCNFs), which was used as the freestanding anode of PIHCs the freestanding anode of PIHCs to alleviate large volume expansion and increase conductivity. Benefiting from the B, F co-doping and porous interlace nanostructure of BF-PCNFs, the anode shows 185 mA h g−1 under a load of 12.6 mg cm−2, a reversible capacity of 176 mA h g−1 at 1000 mA g−1 after 6000 cycles, and the capacity retention from 100 mA g−1 to 5000 mA g−1 is 62%. Furthermore, the PIHCs based on BF-PCNFs as anode and activated carbon as cathode exhibit an energy density of 87 Wh kg−1 and a power density of 393 W kg−1. The capacity retention is as high as 78% over 4000 cycles. Considering the exceptional rate performance, long cyclability and high-mass-loading, our work may supply a new strategy for designing novel energy storage devices with outstanding performance.

Characterizing the Correlation Between Angiogenesis and Osteogenesis In Vivo Using Multicontrast Functional Imaging in a Calvarial Defect Model

Angiogenesis is a key factor in bone healing that allows the delivery of oxygen, nutrients, inflammatory and bone precursor cells to the defect site. It induces dramatic structural and functional remodeling of the vasculature during the first 4 weeks of bone healing. Although recent advances in optical imaging have elucidated the in vivo relationship between angiogenesis and osteogenesis in a calvarial defect model, these efforts were mostly limited to structural imaging of the vasculature and bone. Therefore, to better characterize changes in vascular function (i.e. blood flow, oxygenation, etc.) during the bone healing cascade we developed a multicontrast optical imaging framework to assess in vivo changes in microvascular architecture using intrinsic optical signal (IOS) imaging; changes in blood flow with laser speckle contrast (LSC) imaging; and bone formation with bright‐field imaging at high spatial (5 µm) and temporal (200 ms) resolutions. With this system we acquired multicontrast images from 10 animals with calvarial defects every 2 days, over 4 weeks (Fig. 1a, d). The bone and vasculature were then digitally segmented from the bright‐field and IOS images for quantitative analysis (Fig. 1b, c). We also euthanized an animal each week for assessing 3D changes in bone volume and vascular architecture using an ex vivo, high‐resolution (10 µm) CT imaging workflow we recently developed called VascuViz (Fig. 2a, b, d). Using this framework, we demonstrated that angiogenic remodeling within the bone defect microenvironment was most robust from post injury day (D) 4 to D10, during which blood vessel length, volume and density all showed significant increase (Fig. 2c). The blood flow exhibited a sudden increase at D6 when angiogenesis started, and the angiogenic vessels were most perfused at D12 (Fig. 1d). These vascular changes peaked by the end of week 2 and plateaued during the next 2 weeks which were correlated with a large increase in bone volume during the first 2 weeks and smaller increase during the last 2 weeks (Fig. 2e). These results indicate that both structural and functional changes of the microvascular system strongly correlate with bone growth during the early stages of bone healing.Next, we plan to include additional indices of vascular function such as vessel maturity and intravascular oxygenation, as well as image‐based hemodynamic models to further characterize the role of the vascular microenvironment during osteogenesis. We believe that this novel imaging framework for characterizing the defect microenvironment can be utilized to inform the design of novel tissue engineering (TE) constructs for craniofacial bone regeneration. Collectively, these advances herald a new era of “image‐based TE”.

Loops, topologically associating domains, compartments, and territories are elastic and robust to dramatic nuclear volume swelling

Layers of genome organization are becoming increasingly better characterized, but less is known about how these structures respond to perturbation or shape changes. Low-salt swelling of isolated chromatin fibers or nuclei has been used for decades to investigate the structural properties of chromatin. But, visible changes in chromatin appearance have not been linked to known building blocks of genome structure or features along the genome sequence. We combine low-salt swelling of isolated nuclei with genome-wide chromosome conformation capture (Hi-C) and imaging approaches to probe the effects of chromatin extension genome-wide. Photoconverted patterns on nuclei during expansion and contraction indicate that global genome structure is preserved after dramatic nuclear volume swelling, suggesting a highly elastic chromosome topology. Hi-C experiments before, during, and after nuclear swelling show changes in average contact probabilities at short length scales, reflecting the extension of the local chromatin fiber. But, surprisingly, during this large increase in nuclear volume, there is a striking maintenance of loops, TADs, active and inactive compartments, and chromosome territories. Subtle differences after expansion are observed, suggesting that the local chromatin state, protein interactions, and location in the nucleus can affect how strongly a given structure is maintained under stress. From these observations, we propose that genome topology is robust to extension of the chromatin fiber and isotropic shape change, and that this elasticity may be beneficial in physiological circumstances of changes in nuclear size and volume.

Optical Characterization of Fresh and Photochemically Aged Aerosols Emitted from Laboratory Siberian Peat Burning

Carbonaceous aerosols emitted from biomass burning influence radiative forcing and climate change. Of particular interest are emissions from high-latitude peat burning because amplified climate change makes the large carbon mass stored in these peatlands more susceptible to wildfires and their emission can affect cryosphere albedo and air quality after undergoing transport. We combusted Siberian peat in a laboratory biomass-burning facility and characterized the optical properties of freshly emitted combustion aerosols and those photochemically aged in an oxidation flow reactor (OFR) with a three-wavelength photoacoustic instrument. Total particle count increased with aging by a factor of 6 to 11 while the total particle volume either changed little (&lt;8%) for 19 and 44 days of equivalent aging and increased by 88% for 61 days of equivalent aging. The aerosol single-scattering albedo (SSA) of both fresh and aged aerosol increased with the increasing wavelength. The largest changes in SSA due to OFR aging were observed at the shortest of the three wavelengths (i.e., at 405 nm) where SSA increased by less than ~2.4% for 19 and 44 days of aging. These changes were due to a decrease in the absorption coefficients by ~45%, with the effect on SSA somewhat reduced by a concurrent decrease in the scattering coefficients by 20 to 25%. For 61 days of aging, we observed very little change in SSA, namely an increase of 0.31% that was caused a ~56% increase in the absorption coefficients that was more than balanced by a somewhat larger (~71%) increase in the scattering coefficients. These large increases in the absorption and scattering coefficients for aging at 7 V are at least qualitatively consistent with the large increase in the particle volume (~88%). Overall, aging shifted the absorption toward longer wavelengths and decreased the absorption Ångström exponents, which ranged from ~5 to 9. Complex refractive index retrieval yielded real and imaginary parts that increased and decreased, respectively, with the increasing wavelength. The 405 nm real parts first increased and then decreased and imaginary parts decreased during aging, with little change at other wavelengths.

Large Magnetic-Field-Induced Strain at the Spin-Reorientation Transition in A-Site Ordered Spinel Oxide LiFeCr4O8

Sintered samples of a spinel oxide LiFeCr4O8, where Cr3+ and Fe3+ ions have localized moments, were found to show a large magnetic-field-induced volume increase approaching 500 ppm by applying a magnetic field of 9 T. This large volume increase appeared only at around 30 K. At 30 K, a spin-reorientation transition from ferrimagnetic to conical order occurs, giving rise to this large volume increase. The coexistence of ferrimagnetic and conical phases at this transition was found to be important, suggesting that such a large magnetic-field-induced volume change can be realized at various magnetic transitions in localized magnets with strong spin-lattice coupling.

Hygro-coupled viscoelastic viscoplastic material model of paper

Paper is a versatile material, which is known of being very sensitive to moisture changes that make the mechanical behavior hard to predict. To close this gap, we propose a mechanical model that captures the transient behavior during the interaction with water. Since the diffusion of water within the paper network happens on a similar time scale as the mechanical relaxation phenomena, a fully coupled theory is motivated. Furthermore, the absorbed water induces a large increase in volume which motivates the application of finite strain theory. The model is derived in a thermodynamically consistent manner and its parameters are estimated with experiments available in the literature. The model shows a good agreement applied to paper curl experiments and provides further insights into complex multi-physics problems.

Modulation of soluble guanylate cyclase ameliorates pulmonary hypertension in a rat model of chronic thromboembolic pulmonary hypertension by stimulating angiogenesis.

Acute pulmonary embolism (PE) does not always resolve after treatment and can progress to chronic thromboembolic disease (CTED) or the more severe chronic thromboembolic pulmonary hypertension (CTEPH). The mechanisms surrounding the likelihood of PE resolution or progress to CTED/CTEPH remain largely unknown. We have developed a rat model of CTEPH that closely resembles the human disease in terms of hemodynamics and cardiac manifestations. Embolization of rats with polystyrene microspheres followed by suppression of angiogenesis with the inhibitor of vascular endothelial growth factor receptor 2 (VEGF‐R2) SU5416 results in transient, acute pulmonary hypertension that progresses into chronic PE with PH with sustained right ventricular systolic pressures exceeding 70 mmHg (chronic pulmonary embolism [CPE] model). This model is similar to the widely utilized hypoxia/SU5416 model with the exception that the “first hit” is PE. Rats with CPE have impaired right heart function characterized by reduced VO2Max, reduced cardiac output, and increased Fulton index. None of these metrics are adversely affected by PE alone. Contrast‐mediated CT imaging of lungs from rats with PE minus SU5416 show large increases in pulmonary vascular volume, presumably due to an angiogenic response to acute PE/PH. Co‐treatment with SU5416 suppresses angiogenesis and produces the CTEPH‐like phenotype. We report here that treatment of CPE rats with agonists for soluble guanylate cyclase, a source of cGMP which is in turn a signal for angiogenesis, markedly increases angiogenesis in lungs, and ameliorates the cardiac deficiencies in the CPE model. These results have implications for future development of therapies for human CTEPH.

Application of a Diatom Transfer Function to Quantitative Paleoclimatic Reconstruction — A Case Study of Yunlong Lake, Southwest China

Although diatom records from lake sediments have been used for quantitative paleoclimatic reconstruction, their validity and sensitivity have rarely been tested rigorously. At Yunlong Lake, an alpine lake in Southwest China, we studied the seasonal succession of diatom assemblages to produce a mean surface water temperature (MSWT) transfer function. In addition, based on the spatial distribution of surface diatom assemblages with water depth, we produced a diatom-water depth (WD) transfer function. Combined with the analysis of diatom assemblages in a sediment core (YL2013-A), changes in surface water temperature and water level over the last ∼100 years were quantitatively reconstructed using the diatom-based transfer functions. Comparison with records of regional meteorology and reservoir water capacity revealed that the diatom-based lake water level reconstruction is a sensitive indicator of short-term fluctuations in precipitation, and it also reflects a long-term stepwise rise in water level caused by the impounding and large-scale extension of the reservoir. In addition, the diatom-inferred MSWT is consistent with the changes in air temperature prior to large-scale human disturbance of the site. However, after the extension of the reservoir, although the regional air temperature continued to increase, the water temperature decreased substantially. This suggests that the large increase in lake water volume in the short term led to a decrease in the average water temperature, which in turn led to the occurrence of a diatom bloom in the cold season. The results demonstrate that diatom transfer functions based on modern observations of the same lake has a high environmental sensitivity and can be used for the quantitative reconstruction of regional climate change. Overall, our findings provide a foundation for the use of lake diatom records for quantitative paleoclimatic reconstruction on various timescales.

The Influence of Growth, Maturation and Resistance Training on Muscle-Tendon and Neuromuscular Adaptations: A Narrative Review.

The purpose of this article is to provide an overview of the growth, maturation and resistance training-related changes in muscle-tendon and neuromuscular mechanisms in youth, and the subsequent effect on performance. Sprinting, jumping, kicking, and throwing are common movements in sport that have been shown to develop naturally with age, with improvements in performance being attributed to growth and maturity-related changes in neuromuscular mechanisms. These changes include moderate to very large increases in muscle physiological cross-sectional area (CSA), muscle volume and thickness, tendon CSA and stiffness, fascicle length, muscle activation, pre-activation, stretch reflex control accompanied by large reductions in electro-mechanical delay and co-contraction. Furthermore, a limited number of training studies examining neuromuscular changes following four to 20 weeks of resistance training have reported trivial to moderate differences in tendon stiffness, muscle CSA, muscle thickness, and motor unit activation accompanied by reductions in electromechanical delay (EMD) in pre-pubertal children. However, the interaction of maturity- and training-related neuromuscular adaptions remains unclear. An understanding of how different neuromuscular mechanisms adapt in response to growth, maturation and training is important in order to optimise training responsiveness in youth populations. Additionally, the impact that these muscle-tendon and neuromuscular changes have on force producing capabilities underpinning performance is unclear.

The interaction of internal wave groups with a uniform sloping boundary

Abstract

Soft dielectric elastomer tubes in an electric field

Soft dielectric elastomers with high relative permittivity, very low modulus and high electric breakdown strength have emerged as promising materials for various applications as sensors, actuators and in energy harvesting and soft robotics. We study the intricate deformation behaviour of a soft dielectric elastomer tube of finite length and closed ends, that carries a dead load, is internally pressurised by an injected fluid and has a high electric potential applied across its walls. As for soft tubes in the absence of a potential, this electro-hyperelastic problem involving very large deformations, exhibits a multitude of possibilities, including homogeneous deformation, inhomogeneous bifurcation, snap-through instabilities and post bifurcation behaviour in the form of propagation of axisymmetric bulges. We develop a coupled Finite Element procedure for the situation where the domains of the mechanical and electrostatic problems coincide. The procedure can handle volume flow rate controlled electro-elastic problems. We use it to study the many aspects of the deformation behaviour and limitations placed by competing failure mechanisms on practical utilisation of the large areal strains and axial actuations that can be produced. If electrical breakdown can be avoided by ingenious design of loading sequences, the large volume increase in the tube due to the triggering of instabilities can be harnessed and has far-reaching technological implications.