RESUMO
Rechargeable zinc aqueous batteries are key alternatives for replacing toxic, flammable, and expensive lithium-ion batteries in grid energy storage systems. However, these systems possess critical weaknesses, including the short electrochemical stability window of water and intrinsic fast zinc dendrite growth. Hydrogel electrolytes provide a possible solution, especially cross-linked zwitterionic polymers that possess strong water retention ability and high ionic conductivity. Herein, an in situ prepared fiberglass-incorporated dual-ion zwitterionic hydrogel electrolyte with an ionic conductivity of 24.32 mS cm-1 , electrochemical stability window up to 2.56 V, and high thermal stability is presented. By incorporating this hydrogel electrolyte of zinc and lithium triflate salts, a zinc//LiMn0.6 Fe0.4 PO4 pouch cell delivers a reversible capacity of 130 mAh g-1 in the range of 1.0-2.2 V at 0.1C, and the test at 2C provides an initial capacity of 82.4 mAh g-1 with 71.8% capacity retention after 1000 cycles with a coulombic efficiency of 97%. Additionally, the pouch cell is fire resistant and remains safe after cutting and piercing.
RESUMO
Since Ni-rich cathode material is very sensitive to moisture and easily forms residual lithium compounds that degrade cell performance, it is very important to pay attention to the selection of the surface modifying media. Accordingly, hydroxyapatite (Ca5 (PO4 )3 (OH)), a tooth-derived material showing excellent mechanical and thermodynamic stabilities, is selected. To verify the availability of hydroxyapatite as a surface protection material, lithium-doped hydroxyapatite, Ca4.67 Li0.33 (PO4 )3 (OH), is formed with ≈10-nm layer after reacting with residual lithium compounds on Li[Ni0.8 Co0.15 Al0.05 ]O2 , which spontaneously results in dramatic reduction of surface lithium residues to 2879 ppm from 22364 ppm. The Ca4.67 Li0.33 (PO4 )3 (OH)-modified Li[Ni0.8 Co0.15 Al0.05 ]O2 electrode provides ultra-long term cycling stability, enabling 1000 cycles retaining 66.3% of its initial capacity. Also, morphological degradations such as micro-cracking or amorphization of surface are significantly suppressed by the presence of Ca4.67 Li0.33 (PO4 )3 (OH) layer on the Li[Ni0.8 Co0.15 Al0.05 ]O2 , of which the Ca4.67 Li0.33 (PO4 )3 (OH) is transformed to CaF2 via Ca4.67 Li0.33 (PO4 )3 F during the long term cycles reacting with HF in electrolyte. In addition, the authors' density function theory (DFT) results explain the reason of instability of NCA and why CaF2 layers can delay the micro-cracking during electrochemical reaction. Therefore, the stable Ca4.67 Li0.33 (PO4 )3 F and CaF2 layers play a pivotal role to protect the Li[Ni0.8 Co0.15 Al0.05 ]O2 with ultra-long cycling stability.
Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , ÍonsRESUMO
INTRODUCTION: Exercise-induced apelin as a myokine is believed to play a role in the improvement of type 2 diabetes mellitus (T2DM) and capillarization. In this study, we evaluated the association between exercise-induced apelin and muscle capillarization. METHODS: Zucker rats underwent a treadmill exercise program. Body composition, muscle strength, muscle size, muscle capillarization, and insulin resistance (homeostatic model assessment [HOMA-IR]) were measured. Apelin levels of skeletal muscle and plasma were then analyzed. RESULTS: Exercise improved body composition (P < 0.05), HOMA-IR (P < 0.05), and grip strength (P < 0.001). In the soleus, the fiber size of T2DM was decreased (P < 0.001), but it increased in fiber size and capillarization after exercise (P < 0.001) occurred. We identified an increase in plasma apelin (P < 0.05) and a decrease in soleus apelin (P < 0.01), as well as an association between soleus apelin and angiogenesis (P < 0.01). DISCUSSION: A role for exercise-induced apelin in improving metabolism indicates the possibility of a new drug target for the treatment of metabolic diseases and repairing skeletal muscle damage. Muscle Nerve 56: 1155-1163, 2017.
Assuntos
Apelina/sangue , Capilares/metabolismo , Diabetes Mellitus Tipo 2/sangue , Músculo Esquelético/metabolismo , Neovascularização Fisiológica/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Biomarcadores/sangue , Diabetes Mellitus Tipo 2/terapia , Teste de Esforço/métodos , Masculino , Força Muscular/fisiologia , Músculo Esquelético/irrigação sanguínea , Condicionamento Físico Animal/métodos , Ratos , Ratos ZuckerRESUMO
Physical exercise and vitamins such as ascorbic acid (ASC) have been recognized as an effective strategy in neuroprotection and neurorehabilitatioin. However, there is a need to find an efficient treatment regimen that includes ASC and low-intensity exercise to diminish the risk of overtraining and nutritional treatment by attenuating oxidative stress. In the present study, we investigated the combined effect of low-intensity physical exercise (EX) and ASC on kainic acid (KA)-induced seizure activity and oxidative stress in mice. The mice were randomly assigned into groups as follows: "KA only" (n = 11), "ASC + KA" (n = 11), "Ex + KA" (n = 11), "ASC + Ex + KA" (n = 11). In the present study, low intensity of swimming training period lasted 8 weeks and consisted of 30-min sessions daily (three times per week) without tail weighting. Although no preventive effect of low-intensity exercise or ASC on KA seizure occurrence was evident, there was a decrease of seizure activity, seizure development (latency to first seizures), and mortality in "ASC + Ex + KA" compared to "ASC + KA", "Ex + KA", and "KA only" group. In addition, a preventive synergistic coordination of low-intensity exercise and ASC was evident in glutathione peroxidase and superoxide dismutase activity compared to separate treatment. These results suggest that low-intensity exercise and ASC treatment have preventive effects on seizure activity and development with alternation of oxidative status.
Assuntos
Ácido Ascórbico/farmacologia , Ácido Caínico , Estresse Oxidativo , Condicionamento Físico Animal , Convulsões/prevenção & controle , Animais , Masculino , Camundongos Endogâmicos ICR , Convulsões/induzido quimicamente , Convulsões/fisiopatologiaRESUMO
INTRODUCTION: Secreted protein acidic and rich in cysteine (SPARC) is associated with skeletal muscle atrophy. Here we examined possibility that resistance training could regulate SPARC expression in muscle atrophy in an immobilized hindlimb model. METHODS: Sprague-Dawley rats underwent resistance ladder training and hindlimb immobilization. Cross sectional area and grip strength were measured. SPARC protein levels in the plantaris and soleus, and serum after exercise and immobilization were then analyzed. RESULTS: Resistance training decreased body weight (P < 0.001) and increased muscle quality (P < 0.001). In the plantaris, muscle atrophy (31.82%) and up-regulated SPARC expression (P < 0.05) after immobilization were alleviated by resistance training. CONCLUSIONS: Resistance training led to suppression of SPARC expression in the plantaris and showed a pretraining effect in atrophied rat muscle. Thus, SPARC may play a pivotal role in muscle homeostasis. Muscle Nerve 53: 951-957, 2016.
Assuntos
Elevação dos Membros Posteriores/efeitos adversos , Músculo Esquelético/metabolismo , Atrofia Muscular/patologia , Atrofia Muscular/reabilitação , Condicionamento Físico Animal , Treinamento Resistido/métodos , Fatores Etários , Análise de Variância , Animais , Peso Corporal , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Regulação da Expressão Gênica/fisiologia , Masculino , Força Muscular , Atrofia Muscular/etiologia , Osteonectina/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Mesh-based computer generated hologram enables realistic and efficient representation of three-dimensional scene. However, the dark line artifacts on the boundary between neighboring meshes are frequently observed, degrading the quality of the reconstruction. In this paper, we propose a simple technique to remove the dark line artifacts by matching the phase on the boundary of neighboring meshes. The feasibility of the proposed method is confirmed by the numerical and optical reconstruction of the generated hologram.
RESUMO
We propose a bar-type three-dimensional holographic head mounted display using two holographic optical elements. Conventional stereoscopic head mounted displays may suffer from eye fatigue because the images presented to each eye are two-dimensional ones, which causes mismatch between the accommodation and vergence responses of the eye. The proposed holographic head mounted display delivers three-dimensional holographic images to each eye, removing the eye fatigue problem. In this paper, we discuss the configuration of the bar-type waveguide head mounted displays and analyze the aberration caused by the non-symmetric diffraction angle of the holographic optical elements which are used as input and output couplers. Pre-distortion of the hologram is also proposed in the paper to compensate the aberration. The experimental results show that proposed head mounted display can present three-dimensional see-through holographic images to each eye with correct focus cues.
RESUMO
Fully analytic mesh-based computer generated hologram enables efficient and precise representation of three-dimensional scene. Conventional method assigns uniform amplitude inside individual mesh, resulting in reconstruction of the three-dimensional scene of flat shading. In this paper, we report an extension of the conventional method to achieve the continuous shading where the amplitude in each mesh is continuously varying. The proposed method enables the continuous shading, while maintaining fully analytic framework of the conventional method without any sacrifice in the precision. The proposed method can also be extended to enable fast update of the shading for different illumination directions and the ambient-diffuse reflection ratio based on Phong reflection model. The feasibility of the proposed method is confirmed by the numerical and optical reconstruction of the generated hologram.
RESUMO
In the retina, a number of degenerative diseases, including glaucoma, diabetic retinopathy, and age-related macular degeneration, may occur as a result of aging. Oxidative damage is believed to contribute to the pathogenesis of aging as well as to age-related retinal disease. Although physiological exercise has been shown to reduce oxidative stress in rats and mice, it is not known whether it has a similar effect in retinal tissues. The aim of this study was to evaluate retinal oxidative stress in naturally-aged mice. In addition, we evaluated the effects of aerobic training on retinal oxidative stress by immunohistochemically evaluating oxidative stress markers. A group of twelve-week-old male mice were not exercised (young control). Two groups of twenty-two-month-old male mice were created: an old control group and a treadmill exercise group. The old control group mice were not exercised. The treadmill exercise group mice ran on a treadmill (5 to 12 m/min, 30 to 60 min/day, 3 days/week for 12 weeks). The retinal thickness and number of cells in the ganglion cell layer of the naturally-aged mice were reduced compared to those in the young control mice. However, treadmill exercise reversed these morphological changes in the retinas. We evaluated retinal expression of carboxymethyllysine (CML), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nitrotyrosine. The retinas from the aged mice showed increased CML, 8-OHdG, and nitrotyrosine immunostaining intensities compared to young control mice. The exercise group exhibited significantly lower CML levels and nitro-oxidative stress than the old control group. These results suggest that regular exercise can reduce retinal oxidative stress and that physiological exercise may be distinctly advantageous in reducing retinal oxidative stress.
Assuntos
Envelhecimento/fisiologia , Estresse Oxidativo , Condicionamento Físico Animal/métodos , Retina/citologia , 8-Hidroxi-2'-Desoxiguanosina , Envelhecimento/metabolismo , Animais , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Lisina/análogos & derivados , Lisina/metabolismo , Masculino , Camundongos , Condicionamento Físico Animal/fisiologia , Retina/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
We propose a method to capture light ray field of three-dimensional scene using focal plane sweeping. Multiple images are captured using a usual camera at different focal distances, spanning the three-dimensional scene. The captured images are then back-projected to four-dimensional spatio-angular space to obtain the light ray field. The obtained light ray field can be visualized either using digital processing or optical reconstruction using various three-dimensional display techniques including integral imaging, layered display, and holography.
Assuntos
Imageamento Tridimensional , Luz , Holografia , Análise EspectralRESUMO
Anti-convulsant effects of physical exercise and lipoic acid (LA), also referred to as thioctic acid with antioxidant activity, were investigated using chemical induced seizure model. We investigated the synergic effect of physical exercise and LA on kainic acid-induced seizure activity caused by oxidative stress. After 8 weeks of swimming training, body weight decreased and endurance capacity increased significantly compared to sedentary mice. Kainic acid (30 mg/kg, i.p.) evoked seizure activity 5 min after injection, and seizure activity peaked approximately 80 min after kainic acid treatment. Median seizure activity score in KA only treated group was 4.55 (range 0.5-5), 3.45 for "LA + KA" group (range 0.5-4.3), 3.12 for "EX + KA" group (range 0.05-3.4, p < 0.05 vs. "KA only" group), 2.13 for "EX + LA + KA" group (range 0.5-3.0, p < 0.05 vs. "EX + KA" group). Also, there was a synergic cooperation of exercise and LA in lowering the mortality in kainic acid treated mice (χ2 = 5.45, p = 0.031; "EX + KA" group vs. "LA + EX + KA" group). In addition, the synergic effect of exercise and LA was found in PGx activity compared to separated treatment ("LA + EX + KA": 37.3 ± 1.36; p < 0.05 vs. "LA + KA" and "EX + KA" group). These results indicate that physical exercise along with LA could be a more efficient method for modulating seizure activity and oxidative stress.
Assuntos
Ácido Caínico/toxicidade , Fármacos Neuroprotetores/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Condicionamento Físico Animal/métodos , Convulsões/prevenção & controle , Ácido Tióctico/administração & dosagem , Animais , Terapia Combinada/métodos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Estresse Oxidativo/fisiologia , Condicionamento Físico Animal/fisiologia , Distribuição Aleatória , Convulsões/induzido quimicamente , Convulsões/metabolismoRESUMO
Herein, an Au-coating layer adjusted on the surface of a Zn metal electrode that effectively suppresses the dendrite growth as well as the mechanisms underlying the dendrite suppression as a result of the zincophilic character of Au is introduced. For the Au-coated Zn metal symmetric cell, uniform deposition of Zn-derived compounds was revealed by operando synchrotron tomography. Microscopic studies demonstrate that the Au-coating layer is induced to form a new Zn-Au alloy during the initial Zn deposition, resulting in stabilized long-term stripping/plating of Zn via the 'embracing effect' that intimately accommodates Zn deposition for further cycles. This property supports the successful operation of symmetrical cells up to 50 mA cm-2 . According to Zn electrodeposition simulation, it is verified that the suppression of dendrite growth is responsible for the electro-conducting Au nanolayer that uniformly distributes the electric field and protects the Zn electrode from corrosion, ultimately promoting uniform Zn growth. The compatibility of the Au-coating layer for full cell configuration is verified using NaV3 O8 as a cathode material over 1 000 cycles. This finding provides a new pathway for the enhancement of the electrochemical performance of ZIBs by suppressing the dendritic growth of Zn by means of a zincophilic Au nanolayer.
RESUMO
The synergic effect of regular exercise and resveratrol, a polyphenolic compound with potent antioxidant activity, was investigated against kainate-induced seizures and oxidative stress in mice. After 6 weeks of swimming training, the total body weight decreased and the blood concentration of lactate stabilized statistically in comparison with the sedentary mice, indicate that the training program increased the aerobic resistance of mice. Kainate (30 mg/kg) evoked seizure activity 5 min after injection, and seizure activity was measured seizure rating scores every 5 min up to 2 h. As previously well known experiments, regular exercise and resveratrol (40 mg/kg, daily supplementation for 6 weeks) have an inhibitory effect on kainate-induced seizure activity and oxidative stress. In particularly, a synergistic cooperation of regular exercise and resveratrol was observed in seizure activity, mortality and oxidative stress especially in SOD activity. These results suggest that regular exercise along with an anti-convulsant agent such as resveratrol could be a more efficient method for the prevention of seizure development than exercise alone.
Assuntos
Antioxidantes/farmacologia , Ácido Caínico/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Condicionamento Físico Animal/fisiologia , Convulsões/induzido quimicamente , Convulsões/prevenção & controle , Estilbenos/farmacologia , Limiar Anaeróbio/efeitos dos fármacos , Limiar Anaeróbio/fisiologia , Animais , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Catalase/metabolismo , Ácido Láctico/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Resveratrol , Convulsões/fisiopatologia , Superóxido Dismutase/metabolismo , Natação/fisiologiaRESUMO
The effects of genistein, a protein tyrosine kinase (PTK) inhibitor, on voltage-dependent K(+) (Kv) 4.3 channel were examined using the whole cell patch-clamp techniques. Genistein inhibited Kv4.3 in a reversible, concentration-dependent manner with an IC(50) of 124.78 µM. Other PTK inhibitors (tyrphostin 23, tyrphostin 25, lavendustin A) had no effect on genistein-induced inhibition of Kv4.3. Orthovanadate, an inhibitor of protein phosphatases, did not reverse the inhibition of Kv4.3 by genistein. We also tested the effects of two inactive structural analogs: genistin and daidzein. Whereas Kv4.3 was unaffected by genistin, daidzein inhibited Kv4.3, albeit with a lower potency. Genistein did not affect the activation and inactivation kinetics of Kv4.3. Genistein-induced inhibition of Kv4.3 was voltage dependent with a steep increase over the channel opening voltage range. In the full-activation voltage range positive to +20 mV, no voltage-dependent inhibition was found. Genistein had no significant effect on steady-state activation, but shifted the voltage dependence of the steady-state inactivation of Kv4.3 in the hyperpolarizing direction in a concentration-dependent manner. The K(i) for the interaction between genistein and the inactivated state of Kv4.3, which was estimated from the concentration-dependent shift in the steady-state inactivation curve, was 1.17 µM. Under control conditions, closed-state inactivation was fitted to a single exponential function, and genistein accelerated closed-state inactivation. Genistein induced a weak use-dependent inhibition. These results suggest that genistein directly inhibits Kv4.3 by interacting with the closed-inactivated state of Kv4.3 channels. This effect is not mediated via inhibition of the PTK activity, because other types of PTK inhibitors could not prevent the inhibitory action of genistein.
Assuntos
Genisteína/farmacologia , Ativação do Canal Iônico/fisiologia , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Shal/antagonistas & inibidores , Tirosina/fisiologia , Animais , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Ativação do Canal Iônico/efeitos dos fármacos , Isoflavonas/farmacologia , Cinética , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Fitoestrógenos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Canais de Potássio Shal/metabolismo , Tirosina/metabolismoRESUMO
The effects of ranolazine, an antianginal drug, on potassium channel Kv4.3 were examined by using the whole-cell patch-clamp technique. Ranolazine inhibited the peak amplitude of Kv4.3 in a reversible, concentration-dependent manner with an IC(50) of 128.31 µM. The activation kinetics were not significantly affected by ranolazine at concentrations up to 100 µM. Applications of 10 and 30 µM ranolazine had no effect on the fast and slow inactivation of Kv4.3. However, at concentrations of 100 and 300 µM ranolazine caused a significant decrease in the rate of fast inactivation, and at a concentration of 300 µM it caused a significant decrease in the rate of slow inactivation, resulting in a crossover of the current traces during depolarization. The Kv4.3 inhibition by ranolazine increased steeply between -20 and +20 mV. In the full activation voltage range, however, no voltage-dependent inhibition was found. Ranolazine shifted the voltage dependence of the steady-state inactivation of Kv4.3 in the hyperpolarizing direction in a concentration-dependent manner. The apparent dissociation constant (K(i)) for ranolazine for interacting with the inactivated state of Kv4.3 was calculated to be 0.32 µM. Ranolazine produced little use-dependent inhibition at frequencies of 1 and 2 Hz. Ranolazine did not affect the time course of recovery from the inactivation of Kv4.3. The results indicated that ranolazine inhibited Kv4.3 and exhibited a low affinity for Kv4.3 channels in the closed state but a much higher affinity for Kv4.3 channels in the inactivated state.
Assuntos
Acetanilidas/farmacologia , Piperazinas/farmacologia , Canais de Potássio Shal/antagonistas & inibidores , Angina Pectoris/tratamento farmacológico , Animais , Células CHO , Células Clonais , Cricetinae , Relação Dose-Resposta a Droga , Cinética , Miocárdio , Técnicas de Patch-Clamp , Ranolazina , Canais de Potássio Shal/genética , Canais de Potássio Shal/metabolismo , Software , TransfecçãoRESUMO
PURPOSE: This study aimed to investigate the effects of leucine-enriched essential amino acid (LEAA) supplementation on muscle fatigue and the level of inflammatory cytokines in wheelchair basketball players after a basketball game and interval training. METHODS: Of the ten recruited wheelchair basketball players (aged 34.5±8.9 years; lean body mass of 34.3±10.0 kg) who had spinal cord injury (SCI) and had undergone amputation, nine participated in the final test. These nine athletes received LEAA supplements (3 times 4.0 g/day) or placebo treatment in a double-blind, randomized, crossover study. We measured variables related to muscular fatigue and inflammatory response before the intense exercise and 4 days after recovery. RESULTS: The significant effect of LEAA supplementation was inhibition of circulating IL-6 levels in the LEAA-treated group compared with the placebo group (P < .05). However, no changes were observed in the TNF-α and creatinine kinase levels. Moreover, analysis of variance analysis showed no significant difference in the relative values of muscle soreness. However, the effect size analysis with Cohen's d reported a significant improvement in the relative values of whole body and back muscle soreness. CONCLUSION: Our results revealed that LEAA supplementation before and after intense exercise could help reduce muscle soreness and IL-6 levels in wheelchair basketball players.
RESUMO
Cu, Al, and 316L stainless steel are the main components of the current collectors and coin-type cells used in the characterization of potassium-ion battery (KIB) materials and are expected to be electrochemically inactive. Herein, their electrochemical stabilities in a nonaqueous potassium-bis(fluorosulfonyl)imide (KFSI)-based electrolyte are investigated. In dynamic- and transient-mode polarization, passivation of each metal is observed to occur below 3.9, 3.8, and 4.05 V versus K+/K for Cu, Al, and 316L stainless steel, respectively, which are considered the threshold potentials. The composition of the passive layers of each metal is determined using time-of-flight secondary-ion mass spectrometry. The passive layers of Cu and Al consist of Cu-O (CuO or Cu2O) and Al-O (Al2O3), respectively, and 316L stainless steel is passivated with an outermost Cr-F (CrF3) layer and an inner Cr-O (Cr2O3) layer. Above the threshold potentials, however, severe corrosion of each metal occurs accompanied by the dissolution of metal ions, which could affect the reliability of experimental results for KIBs using KFSI-based electrolytes.
RESUMO
The purpose of this pilot case study is to investigate the effects of Pilates training on hamstring/quadriceps ratio, trunk strength, shoulder strength, and body composition in adolescent baseball players. Eight adolescent baseball players, 15 years of age, participated in Pilates program (supervised training, 50 min per session for three times a week for 8 weeks) using reformer and Cadillac. The intensity of the program was progressively increased by applying beginner level for 1-2 weeks, intermediate level for 3-6 weeks, and advance level for 7-8 weeks. To verify the effect of the Pilates program on hamstring/quadriceps ratio, trunk strength, shoulder strength and body composition, participants performed bioelectrical impedance analysis and isokinetic testing at pre- and posttraining. After the Pilates training, there were significant increases in body weight (P<0.01), left arm muscle mass (P<0.01), and trunk muscle mass (P<0.01). In addition, there were significant increases in left and right knee flexion peak torque (P<0.01 and P<0.05, respectively), right knee extension peak torque (P<0.05), left and right hamstring/quadriceps ratio (both P<0.01), trunk flexion peak torque (P<0.05) and shoulder flexion peak torque (P<0.05) after 8 weeks of training. Therefore, Pilates training increased muscle mass, hamstring/quadriceps ratio, trunk and shoulder strength, suggesting that it may help baseball players do better performance and prevent future injuries in adolescent players.
RESUMO
PURPOSE: In the present pilot study, we aimed to investigate the effects of the Silverrobics exercise program, which is similar to aerobic dance, on the factors related to glucose metabolism and liver enzymes. METHODS: Eight elderly women with obesity and impaired fasting glucose participated in the Silverrobics exercise program (60 minutes per session for five times a week for 8 weeks). The program was conducted at 50-60% of the heart rate reserve at 1 to 2 weeks and at 60-80% of the heart rate reserve at 3 to 8 weeks. To verify the effect of this 8-week exercise program on glucose metabolism and liver enzymes, blood analysis at pre- and post-training was performed. RESULTS: After the Silverrobics exercise program, there were significant decreases in the glucose (p<0.05), glycated hemoglobin A1c (p<0.05), 1,5-anhydroglucitol (p<0.05), and insulin levels (p<0.01) and homeostatic model assessment of insulin resistance score (p<0.05). However, there were no significant effects on the liver enzymes, except for alkaline phosphatase. The alkaline phosphatase level increased after the Silverrobics exercise program (p<0.05). CONCLUSION: Although the Silverrobics exercise program had no beneficial effects on the liver enzymes, it may play an important role in preventing liver diseases considering the effects on glucose metabolism.
RESUMO
The P2-Na2/3MnO2 compound is one of the attractive cathodes for sodium-ion batteries due to its high initial capacity and abundance of Na and Mn elements in nature. The existence of Mn3+ Jahn-Teller ion, however, impedes electrode performance for long term. Here, we challenge to minimize the effect of the Jahn-Teller distortion caused by Mn3+ in the structure, via substitution of Mn3+ by Co3+ in P2-Na2/3[Mn1-xCox]O2 (x = 0-0.3). The P2-Na2/3[Mn0.8Co0.2]O2 compound substantializes the electrochemical performance with a capacity of about 175 mAh g-1 (26 mA g-1) and retained over 90% of its initial capacity for 300 cycles at 0.1 C (26 mA g-1) and 10 C (2.6 A g-1). The operando X-ray diffraction study indicates that a single-phase reaction is associated with the insertion of sodium ions into the structure, accompanied by a small volume change of approximately 3%. Furthermore, ex situ X-ray diffraction and high-resolution transmission electron microscopy results show that the crystal structure remained after 300 continuous cycles. It is believed that such good electrode performances attribute to the structural stabilization assisted by the presence of Co3+ in the crystal structure. Our finding provides a way to take advantage of low-cost Mn-rich cathode materials for sodium-ion batteries.