Fast Cycle Research Articles

Bright Light During Wakefulness Improves Sleep Quality in Healthy Men: A Forced Desynchrony Study Under Dim and Bright Light (III).

Under real-life conditions, increased light exposure during wakefulness seems associated with improved sleep quality, quantified as reduced time awake during bed time, increased time spent in non-rapid eye movement (NREM) sleep, or increased power of the electroencephalogram delta band (0.5-4 Hz). The causality of these important relationships and their dependency on circadian phase and/or time awake has not been studied in depth. To disentangle possible circadian and homeostatic interactions, we employed a forced desynchrony protocol under dim light (6 lux) and under bright light (1300 lux) during wakefulness. Our protocol consisted of a fast cycling sleep-wake schedule (13 h wakefulness—5 h sleep; 4 cycles), followed by 3 h recovery sleep in a within-subject cross-over design. Individuals (8 men) were equipped with 10 polysomnography electrodes. Subjective sleep quality was measured immediately after wakening with a questionnaire. Results indicated that circadian variation in delta power was only detected under dim light. Circadian variation in time in rapid eye movement (REM) sleep and wakefulness were uninfluenced by light. Prior light exposure increased accumulation of delta power and time in NREM sleep, while it decreased wakefulness, especially during the circadian wake phase (biological day). Subjective sleep quality scores showed that participants rated their sleep quality better after bright light exposure while sleeping when the circadian system promoted wakefulness. These results suggest that high environmental light intensity either increases sleep pressure buildup during wakefulness or prevents the occurrence of micro-sleep, leading to improved quality of subsequent sleep.

1365-P: Intermittent Fasting Modifies Pancreatic Glucosensor Mechanism In Diabetic Mice

Background: A specific feature in type-2 diabetes is beta-cell dysfunction, associated to reduction in glucose-stimulated insulin secretion. This function is high-regulated by the glucose sensor mechanism, conformed by GLUT2 and glucokinase, and their expresión is decreased in type-2 diabetes. Intermittent fasting is a recent option in diet control, with alternate cycles of fasting and feeding. In this study we evaluated intermittent fasting in diabetic mice, and its long-term effect in pancreatic GLUT2 and glucokinase expression. Methods: C57BL6 mice were fed with high fat diet for eight weeks, and then intermittent fasting cycles among four weeks. Weight, total caloric intake, fasting and glucose tolerance were determinated. Changes in insulin and glucokinase expression were evatualed by immunohistochemistry assays. Glucose-stimulated insulin secretion, and PDX1, insulin, GLUT2 and glucokinase mRNAs were analyzed in isolated islets. Results: Intermittent fasting caused weight loss, reduction in total caloric intake decrease and enhanced glucose tolerance. In diabetic mice, glucose-stimulated insulin secretion was restored after intermittent fasting, without significant changes in hormone content. Treated groups with fasting increased gene expression of PDX1, insulin and GLUT2, but decreased glucokinase mRNA and localization in beta-cells, but enhanced alpha-cell possitive presence. Conclusion: Intermittent fasting modifies glucosensor mechanism in pancreatic islets from diabetic mice, through GLUT2, PDX1 and insulin expression, but glucokinase. On future studies we will determine changes glucokinase enzymatic activity, and another transcription factors involved in these effects. Disclosure A.Vilches-flores: None. Y.Padilla-romero: None. Funding UNAM PAPIIT IN225819

The Influence of the Copper Stabilizer On the Current Carrying Capacity of REBCO Tapes and Stacks With Various Joints at High Ramp Rates

In this work, we experimentally investigate the current carrying capacity of single REBCO tapes and stacks made 5 12 mm REBCO tapes with a 25 μm copper stabilizer in liquid helium in comparison with those made of bare tapes with no stabilizer at current ramp rates up to 55 kA/s. The motivation for the research was checking the usability of REBCO stacks as basic sub-elements for high current superconducting cables operating in fast cycling modes at 4.2 K. An original experimental technique was employed to induce the extremely high ramp rates. During the tests, one or 5-folded stacks curled into rings 95 mm dia with different types of joints were charged in the external magnetic field generated by an outer solenoid at ramp rates up to 1.6 T/s. The curled REBCO stacks were either soft-soldered over their entire length or contained local joints only. The maximum screening current induced in the samples during the outer solenoid charging <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> was registered. Our experiments showed that the current carrying capacity of the REBCO tapes and stacks was strongly affected by the absence or presence of the copper stabilizer as well as the type of the joint. The reasons for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> limitation for the copper stabilized and bare samples are also briefly discussed.

Medical Record Information System with Rapid Application Development (RAD) Method

Computer technology that is increasingly developing has created a situation that demands everything to be computerized. Science from technology has also changed the way of life of most Indonesians. The presence of information and communication technology affects the technology applied in information systems, especially the input and output mechanisms. One of them is at the Clinic which requires computer technology in its operations. The design of this website also uses 3 stages of Rapid Application Development (RAD) system design, the result of which is a website for a medical record information system. In order for clinical activities to run smoothly at the Clinic, an information system using the Rapid Application Development (RAD) method is needed because the software development process model is classified as an incremental technique and emphasizes short, short, and fast development cycles. Medical record system testing will be tested using Blackbox Testing and User Acceptance Test (UAT) testing.

Sub-channel analysis code development and core thermal calculation for fast reactor refueling cycle

Sub-channel analysis is an indispensable method for core safety evaluation. As a part of the fast reactor program series, development of SAC-SUB (System analysis code – SUB channel) program has been completed. Experiments performed with a 19-rod test assembly in the fuel failure mockup (FFM) sodium loop in Oak Ridge National Laboratory (ORNL) was selected as the benchmark to verify the SAC-SUB program capability. The maximum outlet temperature deviation is within 5%, which preliminarily verifies the availability of the program for fast reactor. Then the code was used to analyze CEFR thermal response during refueling cycle and MOX equilibrium state. During each refueling cycle, highest sodium temperature occurs in the fourth flow zone, and highest fuel temperature rise occurs in the first flow zone. The highest sodium temperature is 606.8 °C appearing in 3rd cycle, and the highest fuel temperature rise is 880.93 °C appearing in 4th cycle. Maximum temperature rise across the cladding and film do not change much. After reaching MOX core equilibrium state, all the key temperature will reach a lower level compared with refueling transition process, which indicating that the power distribution and flow distribution of the core are more matched in the equilibrium state.

Potential use of bamboo in the phytoremediation in of heavy metals: A review

There are many literature sources focusing on the phytoremediation of woody plants, but there are only few dealing with the phytoremediation of bamboo plants. Phytoremediation technology has the advantages of little disturbance to the environment and low remediation cost. Bamboo mainly exists in tropical and subtropical regions. As an energy plant, bamboo has a fast growth cycle, large biomass, simple cultivation, high economic efficiency, and convenient harvesting, which highlights the advantages of bamboo in phytoremediation. In addition, bamboo plants have good tolerance and uptake ability to heavy metals and have high application potential and development value in uptaking heavy metal contaminated soil. However, due to climate, temperature and other reasons, bamboo cannot be widely planted in most countries. Research status of remediation of heavy metal contaminated soil by bamboo plants is summarized. The feasibility of its application in heavy metal contaminated soil is discussed in this paper. Aiming at the shortcomings of existing research, bamboo plants have a prospect in the field of plant phytoremediation for the future.

PEMBUATAN DISAIN BINGKAI BAMBU KHAS DAERAH SULAWESI SELATAN

. There are as many as 176 species of bamboo in Indonesia out of a total of 1620 bamboo species in the world originating from 80 countries. This means that 10% of the world's bamboo species are in Indonesia. In fact, about 105 types of bamboo in Indonesia are endemic plants. Of the bamboo grown in Indonesia, 50% is endemic bamboo and half of that amount has been utilized by the community.Therefore, the Government considers that bamboo is very important to be developed towards a people's economy with a touch of technology so that the added value of bamboo is better. Bamboo is beneficial for the economy, conservation, and culture. Indonesia is estimated to have more than 1 million hectares of bamboo plants. However, only 25,000 hectares have been managed in the form of forest/bamboo gardens, while the rest is growing sporadically. In Indonesia, bamboo has very promising potential to be put to good use. This plant is also easy to develop and has a relatively fast life cycle with a harvest time of only 3-4 years.Therefore, in order to present a training activity as an embodiment of the preservation of development activities (fine arts), work activities are designed a) Calligraphy sketches/paintings (Lontara Script Art) b) Sketches/paintings of nature or local culture c) Making frames painting from bamboo d) Installation of frames on painting works. The results of the training for a form of xhibition of works. The result of an artistic and cultural training effort (creation, appreciation of art) at the community level. The objects of the training are decorative, beautify the guest house room and mainly reveal the lontara script, the work of the originator of the lontara script, daeng pamatte.Keywords: Souvenir,specia lincreasing,family household,income

Efficacy assessment of different time cycles of nebulized hydrogen peroxide against bacterial and yeast biofilms

The prevention of healthcare-associated infections requires continuous effort. In order to achieve better practical results, the control of environmental microbial biofilms with effective disinfection strategies should be addressed. To test the efficacy of different time cycles of nebulized hydrogen peroxide (H2O2) against bacterial and yeast dry biofilms. The efficacies of a standard cycle (SC) and a fast cycle (FC) of nebulized H2O2 were compared. Microbial biofilms were grown on different material coupons. The metabolic activity of biofilms was determined by XTT assay, and the total biomass of biofilms was determined by crystal violet assay. Regarding the efficacy of nebulized H2O2 against biofilms, the mean reduction in metabolic activity for the SC was 55.2% [standard deviation (SD) 19.4%], compared with 50.4% (SD 17.7%) for the FC. The mean reduction in total biomass for the SC was 45.5% (SD 22.7%), compared with 46.7% (SD 21.7%) for the FC. No significant differences were found between the tested cycles and materials. H2O2 nebulization was found to exhibit good efficacy against healthcare-associated microbial dry biofilms. Moreover, similar efficacies were found between the SC and the FC.

Revealing the Impact of Fast Charge Cycling on the Thermal Safety of Lithium-Ion Batteries

The safety of the degraded lithium-ion batteries has an essential impact on second life application. This study systematically investigates the thermal safety changes of lithium-ion batteries after deep aging under the fast charge aging path and reveals the degradation mechanisms caused by fast charge cycling. Lithium plating is the primary degradation mechanism, which thickens the solid electrolyte interface film, causes the loss of active lithium and electrolyte, and leads to a significant increase in impedance and a dramatic decrease in capacity. Therefore, compared with the fresh cells, the heat generation rate increases, while the total heat generation is reduced for aged cells. Besides, the thickened solid electrolyte interface film has lower thermal stability, decreasing the self-heating temperature for aged cells. Furthermore, thermal runaway results of partial cells prove that fast charge cycling reduces the thermal stability of the anode, which further proves that the thermal runaway-triggering temperature decrease is the result of the combination of the anode–electrolyte and anode–cathode reactions. Moreover, fast charge cycling reduces the lithium plating potential upon overcharging, which leads to the occurrence of side reactions in advance, creating the ratio of side reaction heat increase of aged cells for thermal runaway triggering. In addition, the loss of active materials reduces the maximum temperature and maximum temperature rise rate of the aged cell. The findings can provide references for battery safety management system optimization and safer battery screening.

Effects of Greenhouse vs. Growth Chamber and Different Blue-Light Percentages on the Growth Performance and Quality of Broccoli Microgreens

Microgreens are a product category with a biochemical content that is currently earning them the status of a functional food. The genotype of the microgreens, and environmental factors, such as the photosynthetic photon flux density (PPFD) and light spectra, can influence the yield and biochemical profile. A landrace of broccoli called ‘Mugnoli’ was compared with a commercial variety (‘Broccolo Natalino’) in two microgreen growing systems (greenhouse vs. growth chamber) and under three growth chamber light spectra (blue, control, control + blue). The results showed that both Mugnoli and Broccolo Natalino can be used to produce microgreens, achieving similar yields, but that Mugnoli showed notably higher polyphenols and antioxidant contents. Due the higher PFFD of the greenhouse environment, microgreens yields were 18% higher than the yields from cultivation in the growth chamber. Regarding the results under different growth chamber spectra, monochromatic blue caused reductions in the microgreens yield and polyphenols content of 13.5% and 14.2%, respectively. In conclusion, Mugnoli can be considered a valuable genetic source for the production of microgreens given its fast crop cycle, good fresh weight production, and, compared to Broccolo Natalino, its superior biochemical content and lower susceptibility to PPFD variations.

Fast Large‐Stroke Sheath‐Driven Electrothermal Artificial Muscles with High Power Densities

AbstractElectrothermal carbon nanotube (CNT) yarn muscles can provide large strokes during thermal cycling. However, the slow cooling rate of thermal muscles limits their applications, since large diameter prior‐art thermal muscles cannot be rapidly cycled. Herein, a fast thermally powered sheath‐driven yarn muscle that uses a hybrid CNT sheath and an inexpensive polymer core, is reported. The stroke recovery rate for the hybrid muscle is much lower at all frequencies than for about the same diameter sheath‐driven muscle, which means that the full cycle contractile mechanical power is much higher than for comparable prior‐art hybrid muscle. More specifically, the coiled sheath‐driven muscle contracts 14.3% at 1 Hz and 7.3% at 8 Hz in air when powered by a square‐wave electrical voltage input, which is 2.9‐ and 11.4‐times the stroke of the coiled hybrid muscle at these respective frequencies. An average power density of 12 kW kg−1 is obtained for a sheath‐driven muscle, which is 42‐times that for human skeletal muscle. These high‐performance results since the heating that drives fast actuation cycles are largely restricted to the muscle sheath, and this sheath is in direct contact with ambient temperature air.

Circadian alignment of early onset caloric restriction promotes longevity in male C57BL/6J mice.

Caloric restriction (CR) prolongs lifespan, yet the mechanisms by which it does so remain poorly understood. Under CR, mice self-impose chronic cycles of 2-hour-feeding and 22-hour-fasting, raising the question whether calories, fasting, or time of day are causal. We show that 30%-CR is sufficient to extend lifespan 10%; however, a daily fasting interval and circadian-alignment of feeding act together to extend lifespan 35% in male C57BL/6J mice. These effects are independent of body weight. Aging induces widespread increases in gene expression associated with inflammation and decreases in expression of genes encoding components of metabolic pathways in liver from ad lib fed mice. CR at night ameliorates these aging-related changes. Thus, circadian interventions promote longevity and provide a perspective to further explore mechanisms of aging.

Understanding the rheology of nanocontacts

Mechanical stiffness, as opposed to softness, is a fundamental property of solids. Its persistence or rheological evolution in vibrating solid-solid nanocontacts is important in physics, materials science and technology. A puzzling apparent liquefaction under oscillatory strain, totally unexpected at room temperature, was suggested by recent experiments on solid gold nano-junctions. Here we show theoretically that realistically simulated nanocontacts actually remain crystalline even under large oscillatory strains. Tensile and compressive slips, respectively of “necking” and “bellying” types, do take place, but recover reversibly even during fast oscillatory cycles. We also show that, counterintuitively, the residual stress remains tensile after both slips, driving the averaged stiffness from positive to negative, thus superficially mimicking a liquid’s. Unlike a liquid, however, rheological softening occurs by stick-slip, predicting largely frequency independent stiffness with violent noise in stress and conductance, properties compatible with experiments. The baffling large amplitude rheology of gold nanocontacts and its consequences should apply, with different parameters, to many other metals.

Differences and origins of hydrocarbon generation characteristics between mudstone and shale in the Seventh Member of the Yanchang Formation, Ordos Basin, China

Organic-rich black shale and dark-grey mudstone are widespread in the Seventh Member of the Yanchang Formation, Ordos Basin. There are obviously differences in geochemical characteristics and hydrocarbon generation potential between black shale and dark-grey mudstone. Based on the detailed organic geochemical examination, this paper reveals the differences in hydrocarbon generation processes and characteristics (activation energy and conversion rate of hydrocarbon generation) between dark-grey mudstone and black shale and the causes for the differences. Black shale is characterized by moderate to very high total organic carbon (TOC) contents (5.08%–39.39%) and its kerogen type belongs to type II1 and type I. Dark-grey mudstone has a characteristic of low to moderate TOC contents (0.64%–7.35%) and its kerogen types are mainly composed of type II2 and type II1. The hydrocarbon generation activation energy of black shale mainly oscillates around 250–310 KJ/mol, and the corresponding hydrocarbon generation threshold is high (the simulated temperature is 400 °C). The process of hydrocarbon generation is characterized by fast conversion rate and short cycle. By contrast, the hydrocarbon generation activation energy of dark-grey mudstone has a wide range (170–360 KJ/mol), and the corresponding hydrocarbon generation threshold is low (the simulated temperature is 230 °C). The process of hydrocarbon generation is characterized by slow conversion rate and long cycle. The difference of hydrocarbon generation process and characteristics between black shale and dark-grey mudstone is mainly affected by macerals composition and organic matter source. The organic matter of black shale mainly originated from algae, and its macerals was mainly composed of alginite. The organic matter of dark-grey mudstone mainly originated from the mixture of algae and terrestrial higher plants (conifers), and its macerals was mainly composed of vitrinite, liptodetrinite and inertinite. The complex macerals composition and organic matter source make the activation energy distribution of dark-grey mudstone more dispersed than that of black shale. In addition, affected by the macerals (e.g sporinite and resinite) with low activation energy from terrestrial higher plants, the activation energy of dark-grey mudstone containing sporinite and resinite in the macerals is lower than black shale. Therefore, the dark-grey mudstone containing algae and terrestrial higher plants corresponds to low hydrocarbon generation threshold, slow conversion rate and long hydrocarbon generation cycle. The black shale containing a large number of algae corresponds to high hydrocarbon generation threshold, fast conversion rate and short hydrocarbon generation cycle. Moreover, the conversion rate of black shale containing radioactive elements and more clay minerals is higher than that of dark-grey mudstone.

A Quantitative Comparison of the Knockdown Efficiencies of CRISPR/Cas9 and CRISPR‐Cas12 in Caenorhabditis elegans

Currently, many gene editing studies employ CRISPR/Cas9, however its low accuracy and knockdown efficiency is problematic. CRISPR‐Cas12, a newer and potentially more accurate variant, is hypothesized to have a higher knockdown efficiency than CRISPR/Cas9 in Saccharomyces cerevisiae and various plants. However this has not been quantitatively verified in mammalian cells. Our study compares the loss of gene function efficiencies of CRISPR/Cas9 and CRISPR‐Cas12 through decreasing green fluorescent protein (GFP) expression in Caenorhabditis elegans via CRISPR‐mediated deletion. We used the LP162 strain of C. elegans which endogenously expresses GFP. We used C. elegans due to the similarity of molecular pathways to those of humans, their simple anatomy, and their fast reproductive cycle. Through bacterial transformation, we expressed our modified plasmid (containing the gRNA sequence, Cas endonuclease sequence, and C. elegans‐specific promoters) in Escherichia coli. The C. elegans subsequently ingested the transformed bacteria. Fluorescence and protein expression were used as assays to determine the efficacy of CRISPR‐mediated GFP deletion. We hope to show a quantitative assessment of the difference in loss of function efficiencies between CRISPR/Cas9 and CRISPR‐Cas12 when used to delete GFP in C. elegans. Our goal is for these findings to be valuable for researchers seeking to use the most efficient Cas endonuclease for gene knockdown experiments.

Drought, megafires and flood - climate extreme impacts on catchment-scale river water quality on Australia's east coast

Increased frequency and intensity of drought, wildfires and flooding due to climate change has major implications for river water quality, yet there are limited high-temporal resolution data capturing the combined transient impacts of these extreme events at large catchment scales. We present flow-stratified water quality data from a large coastal catchment (Macleay River, Australia) spanning severe drought and extensive fires followed by flooding. We examine concentrations (C), discharge (Q) and flux of suspended sediment, major ions, dissolved organic carbon (DOC) and key nutrients (NO3 and PO4), with a focus on the critical first-flush period after the fires. Highly elevated suspended sediment (∼5500 mg L−1; >100x median pre-fire levels) during the initial post-fire period reflected enhanced erosion from fire-impacted, high-relief landscapes, with peak monthly suspended sediment loads of ∼1.1–3.7 t ha−1. The greatest sensitivity to erosion was during initial flow events following fire, highlighting the compounding effect of sequential extreme events on sediment transport. Maximum solute concentrations typically occurred during the first hydrograph peak post-fire with significantly (P = 0.01) elevated major ions following the order of K>Ca>SO4>HCO3≈Mg>Cl>Na, broadly reflecting the composition of ash materials. Distorted CQ relationships for major ions, DOC and nutrients indicated mobilisation behaviour and enhanced surface runoff during initial hydrograph peaks post-fire, with mean concentrations and CQ relationships progressively shifting to those approximating pre-fire within ∼3–12 months. Elevated DOC (∼7x; P = 0.01) displays distinct changes in fluorescence excitation-emission matrix spectral characteristics, attributable to both fire and drought. Both NO3N (160 μM) and PO4 (7.5 μM) were significantly elevated after the fires (∼15–22x; P = 0.01), with maximum monthly loads of 0.82 and 0.14 kg ha−1 respectively. Fast biogeochemical cycling of dissolved inorganic nitrogen (DIN) species occurred during initial flow events following fire, with NH4N initially dominant (>80% of DIN) and exceeding ecosystem guideline threshold values (>100 μM NH4N), followed by rapid (∼1 week) nitrification. The extreme dynamism and transience of water quality parameters highlights the critical importance of high-frequency sampling to adequately capture the compound impacts drought, fires and floods on aquatic systems.

Microbial properties in tropical montane forest soils developed from contrasting parent material—An incubation experiment

AbstractBackgroundSoil microbes are key drivers of carbon (C) and nutrient cycling in terrestrial ecosystems, and their properties are influenced by the relationship between resource demand and availability.AimsOur objective was to investigate patterns of microbial properties and their controls to understand whether they differ between soils derived from geochemically contrasting parent material in tropical montane forests.MethodsWe measured microbial biomass C (MBCSoil), potential extracellular enzyme activity (pEEA), and assessed microbial investments in C and nutrient acquisition at the beginning and end of a 120‐day laboratory incubation experiment using soils developed from three geochemically contrasting parent material (i.e., mafic, mixed sediment, and felsic) and three soil depths (0–70 cm).ResultsWe found that MBCSoil and pEEA were highest in soils developed from the mafic parent material. Microbial investment in C acquisition was highest in soils developed from mixed sedimentary rocks and lowest in soils developed from the felsic parent material. We propose that our findings are related to the strength of contrasting mineral‐related C stabilization mechanisms and varying C quality. No predominant microbial investment in nitrogen (N) acquisition was observed, whereas investment in phosphorus (P) acquisition was highest in subsoils. We found lower microbial investment in C acquisition in subsoils indicating relatively high C availability, and that microbes in subsoils can substantially participate in C cycling and limit C storage if moisture and oxygen conditions are suitable. Geochemical soil properties and substrate quality were important controls on MBCSoil per unit soil organic C (MBCSOC), particularly after the exhaustion of labile and fast cycling C, that is, at the end of the incubation.ConclusionAlthough a laboratory incubation experiment cannot reflect real‐world conditions, it allowed us to understand how soil properties affect microbial properties. We conclude that parent material is an important driver of microbial properties in tropical montane forests despite the advanced weathering degree of soils.

How Prussian Blue Analogues Can Be Stable in Concentrated Aqueous Electrolytes

Prussian blue analogues (PBAs) are promising candidates for storing various ions in aqueous electrolytes. But they often suffer from metal-ion dissolution induced structural degradation, resulting in fast capacity fade and short cycle life. Long-term cycling of PBAs has recently been successfully demonstrated by using highly concentrated aqueous electrolytes, while the stabilization mechanism of PBAs in the electrolytes has remained unclear. In this work, the experimental and molecular modeling evidence indicates that the hydrophobic layer on the PBA/electrolyte interface and the highly restricted network in the concentrated aqueous electrolyte both play critical roles in suppressing metal-ion dissolution of PBAs. That explains why the NH4+ full battery consisting of a PBA cathode can be stably cycled over 4000 cycles with 72.3% capacity retention (8C). The molecular-level understanding of the stabilization mechanism establishes a guiding principle for the stable storage of diverse ions in PBAs, including but not limited to NH4+, Li+, Na+, Mg2+, etc.

Metabolic Profiling and Integration of Metabolomic and Transcriptomic Data From Pectoralis Muscle Reveal Winter-Adaptive Metabolic Responses of Black-Capped Chickadee and American Goldfinch

Seasonal changes, such as alterations in food availability or type and cold conditions, present challenges to free-living birds living in highly seasonal climates. Small birds respond to such challenges through seasonal metabolic flexibility, which better matches seasonal metabolic phenotypes to environmental conditions and can improve fitness. To better understand the mechanistic basis of this metabolic flexibility, we conducted a large-scale metabolic profiling of pectoralis muscle in black-capped chickadees (Poecile atricapillus) and American goldfinches (Spinus tristis), which are small, year-round bird species of temperate-zones. We analyzed muscle samples using non-biased, global metabolomics profiling technology based on UHLC/MS/MS2 platforms. A total of 582 metabolites was characterized for summer and winter season samples. Chickadees showed greater seasonal separation of global metabolite profiles than goldfinches, which is consistent with previous transcriptomic studies of pectoralis muscle in these two species. Reduced levels of amino acids during winter occurred in both species and might reflect decreasing dietary protein intake, amino acid shuttling to other pathways for thermogenesis and/or elevated rates of protein turnover in the pectoralis muscle. Concomitant decreased abundances in tricarboxylic acid cycle (TCA) metabolites suggest faster cycling of the oxidative phosphorylation pathway in winter to meet the metabolic demands of thermogenesis. Accordingly, chickadees displayed shifts toward lipid oxidation in winter, whereas goldfinches showed winter declines in ketone bodies, which suggests increased energy demand or subtle changes in substrate availability. Beyond the winter-specific changes in metabolite abundances, integration of the metabolomic and the transcriptomic data revealed a landscape of gene–metabolite associations related to the winter-adaptive metabolic response. This landscape of gene–metabolite pairs was overrepresented by pathways associated with transport of small molecules, metabolism of amino acids and derivatives, activation and biosynthesis of fatty acid derivatives, and biosynthesis and metabolism of nicotinate and nicotinamide derivatives. Collectively, our results suggest that increased levels of NADH and its derivatives in the pectoralis muscle are a potential novel mechanism for increasing winter metabolic output, fueled by lipids, for thermogenesis during winter.

Electrochemical Modeling and Experimental Verification of Lithiation Gradients in Oxide Cathodes of Lithium-Ion Cells

Lithiated nickel-cobalt-manganese oxides, such as NCM523, are used in the positive electrode (cathode) of Li-ion cells. Using operando X-ray diffraction profilometry, lithiation gradients in the cathode matrix can be observed and quantified by expansion into Legendre polynomials with time-dependent weights. These weights (referred to as gradients) increase in magnitude when electric current flows through the cell, decrease during potentiostatic hold and finally relax to zero when the current is interrupted during open circuit rest. Both physics-based electrochemical models and operando X-ray experiments suggest that the time constants for gradient growth and abatement are primarily determined by ionic diffusion in the oxide particles, which in turn depends on their lithium content. In contrast, the magnitude of gradients depends mainly on the applied current. The X-ray profilometry provides a way of directly probing the formation and disappearance of Li gradients across the cathode during fast cycling, which can help to diagnose the effects of material degradation in the cells.