Anti-skin aging effects and bioavailability of collagen tripeptide and elastin peptide formulations in young and middle-aged women

Background:Collagen peptides(CP),including tripeptides and elastin peptides(EP),are known for their in vitro and in vivo anti-skin aging effects.Despite positive results in animal models,the combination effects of CP and EP and the bioavailability of CP in human studies,particularly in young and middle-aged women,remain underexplored.Objective:To evaluate the effects of an orally administered collagen drink combining CP and EP on the skin health of young and middle-aged women.Materials and Methods:A single-center,randomized,double-blind,parallel-controlled trial was conducted,utilizing the WONDERLABR fish collagen tripeptide beverage.Participants consumed the drink over an 8-week period.Results:Compared to the placebo group,the collagen drink group showed significant improvements in skin hydration(39.19%increase),transepidermal water loss(33.45%decrease),skin elasticity(25.37%increase),dermal collagen content(21.64%increase),pore size(7.94%decrease),wrinkle length(18.09%decrease),skin smoothness(2.85%improvement),and skin roughness(15.32%decrease).Overall pore volume decreased by 60%,and visual assessments indicated a decrease in skin luminosity by 15.20%and smoothness index by 22.55%.Mass spectrometry demonstrated a significant increase in collagen efficacy components,including blood pH and GPH levels(P<0.05).Conclusion:The study confirmed the combination nourishing and anti-skin aging effects of EP and CP on the skin of young and middle-aged women,demonstrating significant improvements in various skin parameters and good bioavailability of collagen peptides.

Experimental Proposal on Non-Hermitian Skin Effect by Two-dimensional Quantum Walk with a Single Trapped Ion

Non-Hermitian Hamiltonians are widely used in describing open systems with gain and loss,among which a key phenomenon is the non-Hermitian skin effect.Here we report an experimental scheme to realize a twodimensional(2D)discrete-time quantum walk with non-Hermitian skin effect in a single trapped ion.It is shown that the coin and 2D walker states can be labeled in the spin of the ion and the coherent-state lattice of the ion motion,respectively.We numerically observe a directional bulk flow,whose orientations are controlled by dissipative parameters,showing the emergence of the non-Hermitian skin effect.We then discuss an experimental implementation of our scheme in a laser-controlled trapped Ca^(+)ion.Our experimental proposal may be applicable to research of dissipative quantum walk systems and may be able to generalize to other platforms,such as superconducting circuits and atoms in cavity.

Effects of 1-methylcyclopropene on skin greasiness and quality of'Yuluxiang'pear during storage at 20℃

During storage at 20℃,specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit senescence.Among these varieties,‘Yuluxiang’is particularly susceptible to peel greasiness,resulting in significant economic losses.Therefore,there is an urgent need for a preservative that can effectively inhibit the development of greasiness.Previous studies have demonstrated the efficacy of 1-methylcyclopropene(1-MCP)in extending the storage period of fruits.We hypothesize that it may also influence the occurrence of postharvest peel greasiness in the‘Yuluxiang’pears.In this study,we treated‘Yuluxiang’pears with 1-MCP.We stored them at 20℃while analyzing the composition and morphology of the surface waxes,recording enzyme activities related to wax synthesis,and measuring indicators associated with fruit storage quality and physiological characteristics.The results demonstrate that prolonged storage at 20℃leads to a rapid increase in skin greasiness,consistent with the observed elevations in L^(*),greasiness score,and the content of total wax and greasy wax components.Moreover,there were indications that cuticular waxes underwent melting,resulting in the formation of an amorphous structure.In comparison to controls,the application of 1-MCP significantly inhibited increments in L^(*) values as well as grease scores while also reducing accumulation rates for oily waxes throughout most stages over its shelf period,additionally delaying transitions from flaky-wax structures towards their amorphous counterparts.During the initial 7 d of storage,several enzymes involved in the biosynthesis and metabolism of greasy wax components,including lipoxygenase(LOX),phospholipase D(PLD),andβ-ketoacyl-CoA synthase(KCS),exhibited an increase followed by a subsequent decline.The activity of LOX during early shelf life(0–7 d)and the KCS activity during middle to late shelf life(14–21 d)were significantly suppressed by 1-MCP.Additionally,1-MCP effectively maintained firmness,total soluble solid(TSS)and titratable acid(TA)contents,peroxidase(POD),and phenylalanine ammonia-lyase(PAL)activities while inhibiting vitamin C degradation and weight loss.Furthermore,it restrained polyphenol oxidase(PPO)activity,ethylene production,and respiration rate increase.These findings demonstrate that 1-MCP not only delays the onset of peel greasiness but also preserves the overall storage quality of‘Yuluxiang’pear at a temperature of 20℃.This study presents a novel approach for developing new preservatives to inhibit pear fruit peel greasiness and provides a theoretical foundation for further research on pear fruit preservation.

Hybrid Skin-Topological Effect Induced by Eight-Site Cells and Arbitrary Adjustment of the Localization of Topological Edge States

Hybrid skin-topological effect(HSTE)in non-Hermitian systems exhibits both the skin effect and topological protection,offering a novel mechanism for localization of topological edge states(TESs)in electrons,circuits,and photons.However,it remains unclear whether the HSTE can be realized in quasicrystals.

Diet with high content of advanced glycation end products induces oxidative stress damage and systemic inflammation in experimental mice: protective effect of peanut skin procyanidins

Non-enzymatic glycation reaction in food can produce diet-derived advanced glycation end products(dAGEs),which have potential health risks.Thus,it is of great significance to find efficient substances to improve the negative effects induced by dAGEs on human health.This study investigated the intervening effects of peanut skin procyanidins(PSP)on the dAGEs-induced oxidative stress and systemic inflammation in experimental mice model.Results showed that the accumulation of AGEs in serum,liver,and kidney was significantly increased after mice were fed dAGEs(P<0.05).The expression of advanced glycation product receptor(RAGE)was also significantly increased in liver and kidney(P<0.05).PSP could not only effectively reduce the accumulation of AGEs in serum,liver and kidney of mice,but also reduce the expression of RAGE in liver and kidney of mice.And the levels of pro-inflammatory cytokines interleukin-6(IL-6),tumor necrosis factor(TNF-α),and IL-1βin serum of mice were significantly decreased(P<0.05),while the levels of antiinflammatory factor IL-10 were increased,and the inflammatory injury in mice was improved.In addition,the levels of superoxide dismutase(SOD),glutathione(GSH),catalase(CAT)in liver and kidney of mice were increased(P<0.05),and the level of malondialdehyde(MDA)was decreased(P<0.05),which enhanced the antioxidant capacity of mice in vivo,and improved the oxidative damage of liver and kidney.Molecular docking technique was used to confirm that the parent compound of procyanidins and its main metabolites,such as 3-hydroxyphenylacetic acid,could interact with RAGE,which might inhibit the activation of nuclear transcription factor(NF-κB),and ultimately reduce oxidative stress and inflammation in mice.

Research on the Nursing Effect of Glycolipids on Acne Skin

Glycolipids are lipid compounds,which are a type of amphiphilic molecules containing glycosyl ligands.This experiment studied the efficacy of glycolipids on acne skin care from the aspects of antibacterial,anti-inflammatory,anti-allergic,oil-control,soothing and repair.Research results show that glycolipids have excellent antibacterial properties against P.acnes;when the dosage of glycolipids reaches 10μg/mL,the inhibition rate of glycolipids on lipid synthesis in SZ95 cells can reach 20%;glycolipids can induce LPS induction RAW264.7 cells have the inhibitory effect on the release of inflammatory factors IL-6 and NO;when the glycolipids concentration is 15 mg/mL,the inhibition rate of glycolipids on hyaluronidase reaches 45.8%;when the glycolipids concentration is 25μg/mL,the inhibition rate on calcium ion concentration reaches 45.3%;glycolipids have a significant promoting effect on wound healing.Furthermore,human efficacy evaluation shows that glycolipids products have comprehensive care effects on acne skin.This study will help further promote the application of glycolipids in cosmetic products,especially in skin care products for acne skin.

Exploration of the Evaluation Method for the Soothing Effect of UV Induced Human Skin Damage Model

To explore the method of evaluating the soothing effect of human skin damage,a human skin damage model was established using UV light induction.Four test areas were set up,namely blank control area,UV damage prevention and soothing area,immediate soothing area after UV damage and soothing area after UV damage.Five skin parameters,including skin melanin,red pigment value,skin pigmentation value,a*value,and skin redness value,were used to characterize skin pigmentation before and after using the sample Changes in properties such as skin erythema and skin pigment.The results showed that the method showed significant changes in the skin condition of volunteers before and after using the sample,and could achieve a soothing effect,which has certain reference significance.

The Effect of a Novel Complex, Composed of Ceramide, Energizing Peptide and Camu Camu Extract, on Epidermal Barrier Function and Dermal Antiaging Properties in Ex Vivo Human Skin Small Live Cohort

The skin’s primary function is to protect the body against a spectrum of environmental stressors, including mechanical insults, microorganisms, chemicals, and allergens. Located in the outermost layers, the primary structures and components responsible for the skin’s barrier function are susceptible to environmental variables, dermatological conditions, and the aging process. The ensuing alterations to structure, composition, and organizational attributes of the epidermal barrier can impact its integrity and functionality. The aim of this study was to assess the effect of a novel complex composed of a ceramide, energizing peptide, and Camu Camu extract (SUPCERATTM complex) on specific markers of epidermal barrier integrity, as well as epidermal and dermal function. All the experiments were conducted on fresh human abdominal skin explants. Intradermal production of hyaluronic acid, epidermal claudin-1, and ceramide synthase 3 expressions, as well as epidermal lipids content were assessed using specific fluorescent stainings on ex vivo skin after the application of the complex or placebo. Additionally, dermal elastase and collagenase activities were assessed using in tubo enzymatic assays. Lastly, the effect of a cosmetic cream containing SUPCERATTM complex was assessed using subjective Global Aesthetic Improvement Scale (GAIS) in a small cohort of patients after 60 days of use. The application of the SUPCERATTM complex on ex vivo skin led to significant increase in dermal hyaluronic acid content and epidermal activity of claudin-1, ceramide synthase 3 and epidermal ceramide content. Furthermore, in tubo enzymatic assays demonstrated inhibition of both dermal elastase and collagenase activities. In addition, the patient-reported results indicated significant improvements in skin quality and appearance. .

Evaluating the effect of moisturizers containing endogenous lipids on skin barrier properties

Lipids in stratum corneum are largely responsible for skin barrier function.There have been numerous studies on skin barrier repairing and moisturizing effects of products containing occlusives,emollients and humectants.However,currently there are few studies systematically evaluating effect of moisturizers containing endogenous lipids on skin barrier properties.The objective of this study was to study the effect of products containing endogenous lipids on various barrier-related indicators.A total 89 subjects with dry skin were enrolled.To evaluate the effect of the test products on skin barrier function and hydration after 28 days of use on the face,this study combined clinical assessments of skin condition(skin redness,global appearance of dry line,skin roughness and radiance),instrumental assessments(transepidermal water loss,skin hydration and scaliness)and photo tracking(VISIA-CR,VC20 and 3D in-vivo Reflectance Confocal Microscope).Adverse reactions were also assessed.All test products showed significant improvement in all the attributes assessed by both clinical assessments and instrumental assessments after 28 days of treatment.In addition,the products containing skinidentical ceramides and niacinamide show improvement on TEWL and skin hydration.Two products containing exogenous lipids can improve skin hydration and barrier function which have demonstrated efficacy in improving dry skin condition.

Skin photobiological effect induced by BL:Clinical manifestation,mechanisms,and protection against photodamages

Over the last decade,the rapid advances of life sciences have significantly increased public awareness and comprehension of dermatological knowledge,resulting in widespread acceptance of scientific skincare in society.The scope of photoprotection has expanded to encompass not only ultraviolet radiation but also visible light(including blue light).Furthermore,photoprotection methods have evolved from light blocking to the repair of cellular damage caused by prolonged light exposure via biological signaling pathways.Blue light(BL)is the portion of sunlight between 400 nm(violet)and 500 nm(cyan),that can penetrate deep into biological tissues,with up to 20%reaching subcutaneous tissues.Similar to UV damage,BL can cause oxidative stress,persistent pigmentation,and extracellular matrix degradation,resulting in skin symptoms such as hyperpigmentation,dullness,lack of radiance,uneven skin tone,and wrinkles.This study investigates the clinical manifestations of BL-induced skin photodamages,as well as the underlying biological mechanisms and proposes rational photoaging prevention strategies.

Two-Dimensional Thermal Regulation Based on Non-Hermitian Skin Effect

The non-Hermitian skin effect has been applied in multiple fields.However,there are relatively few models in the field of thermal diffusion that utilize the non-Hermitian skin effect for achieving thermal regulation.Here,we propose two non-Hermitian Su-Schrieffer-Heeger(SSH)models for thermal regulation:one capable of achieving edge states,and the other capable of achieving corner states within the thermal field.By analyzing the energy band structures and the generalized Brillouin zone,we predict the appearance of the non-Hermitian skin effect in these two models.Furthermore,we analyze the time-dependent evolution results and assess the robustness of the models.The results indicate that the localized thermal effects of the models align with our predictions.In a word,this work presents two models based on the non-Hermitian skin effect for regulating the thermal field,injecting vitality into the design of non-Hermitian thermal diffusion systems.

A Polyvinyl Alcohol/Acrylamide Hydrogel with Enhanced Mechanical Properties Promotes Full-Thickness Skin Defect Healing by Regulating Immunomodulation and Angiogenesis Through Paracrine Secretion

Hydrogel-based tissue-engineered skin has attracted increased attention due to its potential to restore the structural integrity and functionality of skin.However,the mechanical properties of hydrogel scaffolds and natural skin are substantially different.Here,we developed a polyvinyl alcohol(PVA)/acrylamide based interpenetrating network(IPN)hydrogel that was surface modified with polydopamine(PDA)and termed Dopa-gel.The Dopa-gel exhibited mechanical properties similar to native skin tissue and a superior ability to modulate paracrine functions.Furthermore,a tough scaffold with tensile resistance was fabricated using this hydrogel by three-dimensional printing.The results showed that the interpenetration of PVA,alginate,and polyacrylamide networks notably enhanced the mechanical properties of the hydrogel.Surface modification with PDA endowed the hydrogels with increased secretion of immunomodulatory and proangiogenic factors.In an in vivo model,Dopa-gel treatment accelerated wound closure,increased vascularization,and promoted a shift in macrophages from a proinflammatory M1 phenotype to a prohealing and anti-inflammatory M2 phenotype within the wound area.Mechanistically,the focal adhesion kinase(FAK)/extracellular signal-related kinase(ERK)signaling pathway may mediate the promotion of skin defect healing by increasing paracrine secretion via the Dopa-gel.Additionally,proangiogenic factors can be induced through Rho-associated kinase-2(ROCK-2)/vascular endothelial growth factor(VEGF)-mediated paracrine secretion under tensile stress conditions.Taken together,these findings suggest that the multifunctional Dopa-gel,which has good mechanical properties similar to those of native skin tissue and enhanced immunomodulatory and angiogenic properties,is a promising scaffold for skin tissue regeneration.

Ultraconformable Integrated Wireless Charging Micro-Supercapacitor Skin

Conformable and wire-less charging energy storage devices play important roles in enabling the fast development of wearable,non-contact soft electronics.However,current wire-less charging power sources are still restricted by limited flexural angles and fragile connection of components,resulting in the failure expression of performance and constraining their fur-ther applications in health monitoring wearables and moveable artificial limbs.Herein,we present an ultracompatible skin-like integrated wireless charging micro-supercapacitor,which building blocks(including electrolyte,electrode and substrate)are all evaporated by liquid precursor.Owing to the infiltration and permeation of the liquid,each part of the integrated device attached firmly with each other,forming a compact and all-in-one configuration.In addition,benefitting from the controllable volume of electrode solution precursor,the electrode thickness is easily regulated varying from 11.7 to 112.5μm.This prepared thin IWC-MSC skin can fit well with curving human body,and could be wireless charged to store electricity into high capacitive micro-supercapacitors(11.39 F cm-3)of the integrated device.We believe this work will shed light on the construction of skin-attachable electronics and irregular sensing microrobots.

240 nm AlGaN-based deep ultraviolet micro-LEDs:size effect versus edge effect

240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge effects.Here,it is revealed that the peak optical output power increases by 81.83%with the size shrinking from 50.0 to 25.0μm.Thereinto,the LEE increases by 26.21%and the LEE enhancement mainly comes from the sidewall light extraction.Most notably,transversemagnetic(TM)mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design.However,when it turns to 12.5μm sized micro-LEDs,the output power is lower than 25.0μm sized ones.The underlying mechanism is that even though protected by SiO2 passivation,the edge effect which leads to current leakage and Shockley-Read-Hall(SRH)recombination deteriorates rapidly with the size further shrinking.Moreover,the ratio of the p-contact area to mesa area is much lower,which deteriorates the p-type current spreading at the mesa edge.These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm,which will pave the way for wide applications of deep ultraviolet(DUV)micro-LEDs.

Jonzac Thermal Spring Water Reinforces Skin Barrier Function of Human Skin and Presents a Soothing and Regenerating Effect

The skin is a formidable physical and biological barrier which communicates continuously with the outside of the body. And the stratum corneum, the outermost layer of human epidermis, plays a central role in the interaction between the cutaneous tissue and the external environment. The horny layer, and more generally the whole skin layers, avoid the penetration of harmful exogenous agents, produce molecules named anti-microbial peptides which impact the composition of the cutaneous microbiota, regulate the internal corporal temperature, avoid the water loss from the inside of the body and constitute an incredible efficient anti-oxidant network. Nevertheless, nowadays, the skin is more and more solicited by the different elements of the cutaneous exposome, including atmospheric pollution and solar radiations, which can cause a dramatic acceleration of the skin ageing process. As a consequence, due to the multifunctional protective role of the skin, during the recent decade the cosmetic industry invested massively in the development of new raw materials and end-products (dermo-cosmetics) able to preserve an optimal state of the skin regarding the external environment. Based on their physical-chemical properties thermal spring waters, which are extremely rich in inorganics ions, are interesting and powerful candidates to be part, as integral component, of new efficient dermo-cosmetic formulations dedicated to protect the skin from the external stimuli. The aim of the present work was to investigate and characterize the activity of Jonzac thermal spring water on the skin. Using different models, we proved for the first time that Jonzac thermal spring water reinforces the barrier function of the skin by modulating the expression of key markers including filaggrin and human beta defensin 2 on ex vivo human skin. The ex vivo and in vivo hydration activity, by Raman spectroscopy and corneometry respectively, has been also demonstrated. We have also shown that Jonzac thermal spring water ameliorates significantly the cutaneous microrelief in vivo. To conclude, we characterize the soothing effect of Jonzac thermal spring water by the analysis of histamine release in Substance P treated skin explants and by measuring the redness of the skin following UV exposure of the skin in vivo. We observed that both parameters decreased following a preventive treatment of the skin with Jonzac thermal spring water. Taken together our results indicate that Jonzac thermal spring water is a promising and powerful dermo-cosmetic which can be used to preserve an optimal state of the cutaneous tissue.

Evaluation of the intracellular lipid-lowering effect of polyphenols extract from highland barley in HepG2 cells

Active ingredients from highland barley have received considerable attention as natural products for developing treatments and dietary supplements against obesity.In practical application,the research of food combinations is more significant than a specific food component.This study investigated the lipid-lowering effect of highland barley polyphenols via lipase assay in vitro and HepG2 cells induced by oleic acid(OA).Five indexes,triglyceride(TG),total cholesterol(T-CHO),low density lipoprotein-cholesterol(LDL-C),aspartate aminotransferase(AST),and alanine aminotransferase(ALT),were used to evaluate the lipidlowering effect of highland barley extract.We also preliminary studied the lipid-lowering mechanism by Realtime fluorescent quantitative polymerase chain reaction(q PCR).The results indicated that highland barley extract contains many components with lipid-lowering effects,such as hyperoside and scoparone.In vitro,the lipase assay showed an 18.4%lipase inhibition rate when the additive contents of highland barley extract were 100μg/m L.The intracellular lipid-lowering effect of highland barley extract was examined using 0.25 mmol/L OA-induced HepG2 cells.The results showed that intracellular TG,LDL-C,and T-CHO content decreased by 34.4%,51.2%,and 18.4%,respectively.ALT and AST decreased by 51.6%and 20.7%compared with the untreated hyperlipidemic HepG2 cells.q PCR results showed that highland barley polyphenols could up-regulation the expression of lipid metabolism-related genes such as PPARγand Fabp4.

Engineering Strategies for Suppressing the Shuttle Effect in Lithium–Sulfur Batteries

Lithium–sulfur(Li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value.Many methods were proposed for inhibiting the shuttle effect of polysulfide,improving corresponding redox kinetics and enhancing the integral performance of Li–S batteries.Here,we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of Li–S batteries.First,the electrochemical principles/mechanism and origin of the shuttle effect are described in detail.Moreover,the efficient strategies,including boosting the sulfur conversion rate of sulfur,confining sulfur or lithium polysulfides(LPS)within cathode host,confining LPS in the shield layer,and preventing LPS from contacting the anode,will be discussed to suppress the shuttle effect.Then,recent advances in inhibition of shuttle effect in cathode,electrolyte,separator,and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for Li–S batteries.Finally,we present prospects for inhibition of the LPS shuttle and potential development directions in Li–S batteries.

Experimental study on the effect of water absorption level on rockburst occurrence of sandstone

To investigate the mechanism of rockburst prevention by spraying water onto the surrounding rocks,15 experiments are performed considering different water absorption levels on a single face.High-speed photography and acoustic emission(AE)system are used to monitor the rockburst process.The effect of water on sandstone rockburst and the prevention mechanism of water on sandstone rockburst are analyzed from the perspective of energy and failure mode.The results show that the higher the ab-sorption degree,the lower the intensity of the rockburst after absorbing water on single side of sand-stone.This is reflected in the fact that with the increase in the water absorption level,the ejection velocity of rockburst fragments is smaller,the depth of the rockburst pit is shallower,and the AE energy is smaller.Under the water absorption level of 100%,the magnitude of rockburst intensity changes from medium to slight.The prevention mechanism of water on sandstone rockburst is that water reduces the capacity of sandstone to store strain energy and accelerates the expansion of shear cracks,which is not conducive to the occurrence of plate cracking before rockburst,and destroys the conditions for rockburst incubation.

High responsivity photodetectors based on graphene/WSe_(2) heterostructure by photogating effect

Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.

“Buckets effect”in the kinetics of electrocatalytic reactions

In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic solutions.Experimental results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant value.We consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant value.This could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the catalyst.Our study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.