Remarkable contamination characteristics, potential hazards and source apportionment of heavy metals in surface dust of kindergartens in a northern megacity of China.

It is essential to understand the impact of heavy metals (HMs) present in the surface dust (SD) of kindergartens on children, who are highly sensitive to contaminated dust in cities in their growth stage. A study was conducted on 11 types of HMs present in the SD of 73 kindergartens in Beijing. This study aims to assess the pollution levels and sources of eleven HMs in Beijing's kindergartens surface dust (KSD), and estimate the potential health risks in different populations and sources. The results indicate that Cd has the highest contamination in the KSD, followed by Pb, Zn, Ni, Ba, Cr, and Cu. The sources of these pollutants are identified as industrial sources (23.7%), natural sources (22.1%), traffic sources (30.4%), and construction sources (23.9%). Cancer risk is higher in children (4.02E-06) than in adults (8.93E-06). Notably, Cr is the priority pollutant in the KSD, and industrial and construction activities are the main sources of pollution that need to be controlled. The pollution in the central and surrounding areas is primarily caused by historical legacy industrial sites, transportation, urban development, and climate conditions. This work provides guidance to manage the pollution caused by HMs in the KSD of Beijing. ENVIRONMENTAL IMPLICATION: Children within urban populations are particularly sensitive to pollutants present in SD. Prolonged exposure to contaminated SD significantly heightens the likelihood of childhood illnesses. The pollution status and potential health risks of HMs within SD from urban kindergartens are comprehensively investigated. Additionally, the contributions from four primary sources are identified and quantified. Furthermore, a pollution-source-oriented assessment is adopted to clearly distinguish the diverse impacts of different sources on health risks, and the priority pollutants and sources are determined. This work holds pivotal importance for risk management, decision-making, and environmental control concerning HMs in KSD.

Advances in the application of metallic isotopes to the identification of contaminant sources in environmental geochemistry.

The development of the economy and society makes heavy metals (HMs) pollution more and more serious. And, pollution source identification is the primary work of environmental pollution control and land planning. Notably, stable isotope technology has a high ability to distinguish pollution sources, and can better reflect the migration behavior and contribution of HMs from diverse sources, which has become a hot research tool for pollution source identification of HMs. Currently, the rapid development of isotope analysis technology provides a relatively reliable reference for pollution tracking. Based on this background, the fractionation mechanism of stable isotopes and the influence of environmental processes on isotope fractionation are reviewed. Furthermore, the processes and requirements for the measurement of metal stable isotope ratios are summarized, and the calibration methods and detection accuracy of sample measurement are evaluated. Besides, the current commonly used binary model and multi-mixed models in the identification of contaminant sources are also concluded. Moreover, the isotopic changes of different metallic elements under natural and anthropogenic conditions are discussed in detail, and the application prospects of multi-isotope coupling in the traceability of environmental geochemistry are evaluated. This work has some guidance for the application of stable isotopes in the source identification of environmental pollution.

Preliminary investigation of soil organic carbon distribution and turnover patterns, and potential pollution sources in and around a typical coking plant in North China.

The variation characteristics of soil organic carbon (SOC) in and around the coking plant area are still unclear. In this work, the concentration and stable carbon isotope composition of SOC in coke plant soils were investigated to preliminarily identify the sources of SOC in and around the plant area, and to characterize soil carbon turnover. Meanwhile, the carbon isotopic technique was used to initially identify the soil pollution processes and sources in and around the coking plant area. The results demonstrate that the SOC content (12.76 mg g-1) of the surface soil in the coking plant is about 6 times higher than that outside the coking plant (2.05 mg g-1), and the variation range of δ13C value of the surface soil in the plant (-24.63～-18.55‰) is larger than that of the soil outside the plant (-24.92～-20.22‰). The SOC concentration decreases gradually from the center of the plant outward with increasing distance, and the δ13C in the middle and north of the plant tends to be positive compared with the δ13C in the west and southeast of the plant. As the increase of soil depth, the SOC content and δ13C value in the plant increases. On the contrary, δ13C value and SOC content outside the plant decreases, with a minor variation. Based on the carbon isotope method, the SOC in and around the coking plant area is mainly from industrial activities (e.g., coal burning and coking), and partly from C3 plants. Notably, organic waste gases containing heavy hydrocarbons, light oils, and organic compounds accumulated in the northern and northeastern areas outside the plant due to south and southwest winds, which may pose an environmental health risk.

Analysis on spatial effect of environmental regulation on upgrading of industrial structure in China.

Transformation and upgrading of industrial structure is the key link to achieve high-quality economic development in China. In recent years, China has begun to eliminate some industries with high energy consumption and high pollution through environmental regulation policies and promote transformation and upgrading the industrial structure. Under multiple pressures such as the shortage of industrial structure and the decline in the demographic dividend, environmental regulation as a binding force will have an significant impact on ecological protection and economic structure adjustment. With the promotion of the inter-regional integration strategy, the links between various regions are becoming closer and closer. Therefore, the environmental regulation policies implemented by the government will not only affect the region, but can also impact neighboring regions. So, how will environmental regulation affect the optimization of industrial structure in the local and surrounding areas and the mechanism and pathways of its impact are theoretical topics worthy of in-depth study, which have important practical significance for exploring the win-win sustainable development path of industrial structure optimization and ecological protection. This paper selects the data of 30 provinces and cities in China from 2009 to 2019, analyses their spatial distribution characteristics, and establishes a spatial Dubin model to explore the spatial effect of environmental regulation intensity on the upgrading of local and adjacent regional industrial structure. The research results show that: (1) China's environmental regulation policy is not developed independently, but has certain relevance in space, that is, regions with higher environmental regulation intensity are adjacent to each other, and regions with lower environmental regulation are adjacent to each other; (2) The intensity of environmental regulation does not directly promote or inhibit the transformation and upgrading of the local industrial structure, but has a positive spatial spillover effect on the upgrading of the industrial structure in the surrounding areas; (3) The impact of environmental regulation policies on the upgrading of industrial structure is mainly reflected through indirect effects.

Role of the stress-responsive two-component system CpxAR in regulating fimbriae expression in Klebsiella pneumoniae CG43.

BACKGROUND: CpxAR is a two-component system that allows bacteria to reorganize envelope structures in response to extracellular stimuli. CpxAR negatively affects type 1 fimbriae expression in Klebsiella pneumoniae CG43, a hypervirulent strain. The involvement of CpxAR in the regulation of type 3 fimbriae expression was investigated. METHODS: cpxAR, cpxA, and cpxR gene-specific deletion mutants were generated. The deletion effects on the expression of type 1 and type 3 fimbriae were analyzed via measuring the promoter activity, mannose sensitive yeast agglutination activity, biofilm formation, and the production of the major pilins FimA and MrkA respectively. RNA sequencing analysis of CG43S3, ΔcpxAR, ΔcpxR and Δfur was employed to study the regulatory mechanism influencing the expression of type 3 fimbriae. RESULTS: Deletion of cpxAR increased type 1 and type 3 fimbrial expression. Comparative transcriptomic analysis showed that the expression of oxidative stress-responsive enzymes, type 1 and type 3 fimbriae, and iron acquisition and homeostasis control systems were differentially affected by cpxAR or cpxR deletion. Subsequent analysis revealed that the small RNA RyhB negatively affects the expression of type 3 fimbriae, while CpxAR positively controls ryhB expression. Finally, the site-directed mutation of the predicted interacting sequences of RyhB with the mRNA of MrkA attenuated the RyhB repression of type 3 fimbriae. CONCLUSION: CpxAR negatively regulates the expression of type 3 fimbriae by modulating cellular iron levels thereafter activating the expression of RyhB. The activated RyhB represses the expression of type 3 fimbriae by base-pairing binding to the 5'region of mrkA mRNA.

Analysis of the Impact of Environmental Perception on the Health Status of Middle-Aged and Older Adults: A Study Based on CFPS 2020 Data.

Health risks and hazards caused by the environment have long been one of the most important public issues of concern to the state, society, and the public. At the same time, population aging is becoming a global issue, and residents' health is the most important component of people's livelihood, and residents can only pursue other rights and interests if they can protect their own health. Therefore, based on the micro data from the fifth round of the China Family Panel Studies (CFPS), this paper uses binary logistic regression with propensity score matching (PSM) to analyze the effect of environmental perception on the health status (including mental health and physical health) of middle-aged and older adults. It was found that environmental perceptions significantly affect the depressive state and sickness status of middle-aged and older adults. Among them, middle-aged and older adults who were female, of rural households, with low education and relatively low income were more affected by environmental shocks on their health. Therefore, we should pay attention to the mental and physical health of middle-aged and older adults and change the existing design concept of aging policy: the government should formulate effective policies and increase corresponding social support; and society and families should also give corresponding care and encourage middle-aged and older adults to exercise more and provide reasonable psychological guidance.

Enhanced Cr (VI) removal with Pb (II) presence by Fe2+-activated persulfate and zero-valent iron system.

Combined heavy metals such as chromium (Cr (VI)) and lead (Pb (II)) in natural water have globally posed severe environmental and public health risk. Here the removal of Cr (VI) and Pb (II) mixed pollutants using Fe2+-activated persulfate (PS) with extra zero-valent iron (ZVI), which was not only a supplementary Fe2+ source, but also a high-efficiency absorbent, was investigated. During removal, pivotal factors of initial pollutant concentration, dosages of ZVI and PS, initial pH and temperatures were examined. Interestingly, generating a lot of H+ in the process of Fe (II) activating persulfate were helpful to the corrosion of ZVI over a large range of pH (1-9). Under the optimum condition, removal efficiency of Pb (II) and Cr (VI) have reached 100% and 94.26% respectively. The removal mechanism was suggested as a three-step reaction that the Pb (II) boosted the removal of Cr (VI) by co-precipitated in wastewater, and the Pb (II) and Cr (VI) were adsorbed and subsequently reduced to Pb0 and Cr3+ as Cr(OH)3 or Cr3+-Fe3+ hydroxides on ZVI surface. Cr (VI) and Pb (II) adsorption kinetics agreed with the pseudo-second-order reaction rate expression. In addition, we were surprised to found that the contribution effect of chromium and lead co-precipitation for their removal by Fe (II) - PS-ZVI has strong dependence on initial pH and concentration ratio of Cr (VI) and Pb (II). The result indicated that Fe (II)-PS-ZVI system should be a favourable removal technology for Cr (VI) and Pb (II).

Enhanced elimination of V5+ in wastewater using zero-valent iron activated by ball milling: The overlooked crucial roles of energy input and sodium chloride.

The ball-milling technology, a highly efficient and cost-effective method, had excellent application prospects for overcoming passivation issues of normal zero-valent iron (ZVI) to enhance the decontamination efficiency. In this work, we investigated the effects and mechanisms of pH, process control agents (PCA), and main process parameters on the removal of V5+ using ball-milled zero-valent iron (ZVIbm). The results showed that ZVI was successfully activated due to mechanochemical action. The enhanced proton conductivity of ZVIbm leaded to the rapid production of more Fe2+, thereby resulting in an order of magnitude higher elimination of V5+ by ZVIbm than by ZVI under near-neutral conditions. In addition, the introduction of NaCl in the ball milling process could not only effectively alleviate the agglomeration phenomenon of ZVIbm, but also effectively enhance its activity. Unexpectedly, due to over-compaction and small size effects, excessive energy input weakened the reactivity of ZVIbm on V5+ elimination. Various characterization results confirmed that the removal of V5+ by ZVIbm was dominated by reduction and supplemented by adsorption. This work updated the basic understanding of the critical effects of process parameters and NaCl on ZVIbm in the remediation of vanadium-containing wastewater.

A high-efficient and recyclable aged nanoscale zero-valent iron compound for V5+ removal from wastewater: Characterization, performance and mechanism.

An effective complex of nanoscale zero-valent iron (NZVI) supported on zirconium 1,4-dicarboxybenzene metals-organic frameworks (UIO-66) with strong oxidation resistance was synthesized (NZVI@UIO-66) for V5+ removal from wastewater. The results demonstrated that NZVI was successfully loaded on UIO-66 with a uniform dispersion, and then the composite was aged in the air which was named A-NZVI@UIO-66. V5+ could be removed quickly and completely using A-NZVI@UIO-66 in a wider pH range except for the pH = 1 condition. The reaction between A-NZVI@UIO-66 and V5+ was an endothermic process. Freundlich model with a better-fitted value showed the adsorption of V5+ on A-NZVI@UIO-66 was multi-layer heterogeneous adsorption and the adsorbed amount of V5+ was 397.23 mg V/g NZVI. Nitrate had a competitive inhibition on V5+ removal by A-NZVI@UIO-66. Mechanisms of vanadium elimination from the aqueous phase by A-NZVI@UIO-66 included physical adsorption, reduction, and complex co-precipitation, particularly the reduction dominated. The subsistent Zr-O bond in A-NZVI@UIO-66 provided a possible double reaction path by playing an electron donor, storage, or conductor role. After acid leaching, A-NZVI@UIO-66 represented good reusability in the removal of V5+ from the practical mine sewage.

Pivotal roles of nanoscale zerovalent iron supported on metal-organic framework material in cadmium (II) migration and transformation in soil.

Cadmium (Cd) contamination in soils is of great concern, and therefore the development of effective remediation technologies for cadmium contamination is urgent. In our study, nano zero-valent iron (NZVI) supported by metal-organic framework (MOF) materials (MOF-NZVI) were prepared using NaBH4 and FeCl3 to try to solve the soil Cd remediation problem. Herein, the effects and the mechanism of MOF-NZVI for the immobilization of Cd in contaminated soil was investigated. The results showed that MOF-NZVI was capable of converting Cd in soil from weak acid extractable and reducible fractions to oxidizable and residual states, thus effectively reducing the toxicity of Cd in soil. FTIR and XRD analysis confirmed that the dominant reaction mechanism between MOF-NVZI and Cd is adsorption with complexation, and the stabilization of Cd is achieved by the formation of compounds such as FeOCdOH.

A review of the new multifunctional nano zero-valent iron composites for wastewater treatment: Emergence, preparation, optimization and mechanism.

Nano zero-valent iron (NZVI) with high chemical reactivity and environmental friendliness had recently become one of the most efficient technologies for wastewater restoration. However, the unitary NZVI system had not met practical requirements for wastewater treatments. Expectantly, the development of NZVI would prefer multifunctional NZVI-based composites, which could be prepared and optimized by the combined methods and technologies. Consequently, a systematic and comprehensive summary from the perspective of multifunctional NZVI-composite had been conducted. The results demonstrated that the advantages of various systems were integrated by multifunctional NZVI-composite systems with a more significant performance of pollutant removal than those of the bare NZVI and its composites. Simultaneously, characteristics of the product prepared by the incorporation of numerous methods were superior to those by a simple method, resulting in the increase of the entirety efficiency. By comparison with other preparation methods, the ball milling method with higher production and field application potential was worthy of attention. After combining multiple technologies, the effect of NZVI and its composite systems could be dramatically strengthened. Preparation technology parameters and treatment effect of contaminants could be further optimized using more comprehensive experimental designs and mathematical models. The mechanism of the multifunctional NZVI system for contaminants treatment was primarily focused on adsorption, oxidation, reduction and co-precipitation. Multiple techniques were combined to enhance the dispersion, alleviating passivation, accelerating electron transfer efficiency or mass transfer action for optimizing the effect of NZVI composites.

African swine fever outbreaks in China led to gross domestic product and economic losses.

African swine fever (ASF) is a fatal and highly infectious haemorrhagic disease that has spread to all provinces in China-the world's largest producer and consumer of pork. Here we use an input-output model, partial equilibrium theory and a substitution indicator approach for handling missing data to develop a systematic valuation framework for assessing economic losses caused by ASF outbreaks in China between August 2018 and July 2019. We show that the total economic loss accounts for 0.78% of China's gross domestic product in 2019, with impacts experienced in almost all economic sectors through links to the pork industry and a substantial decrease in consumer surplus. Scenario analyses demonstrate that the worst cases of pig production reduction and price increase would trigger 1.4% and 2.07% declines in gross domestic product, respectively. These findings demonstrate an urgent need for rapid ASF containment and prevention measures to avoid future outbreaks and economic declines.

Pivotal effects of external Fe2+ on remediation of arsenite by zero-valent iron/persulfate: Efficiencies and mechanism.

Persulfate could be activated by zero-valent iron (ZVI) leading to the rapid removal of various contaminants. However, quick consumption of Fe2+ largely constrained the removal (%) of target pollutants. Here it was reported that Na2S2O8 (SP) combined with ZVI, as an external source of Fe2+, was activated by Fe2+ to quickly (minutes scale) and efficiently (more than 90%) remove As (III) from aqueous solution at an initial pH value from 1.0 to 9.0. As (III) removal was obviously improved by an increase of Fe2+ rather than Na2S2O8 dosage. The removal of As (III) using Fe2+-SP-ZVI system followed the pseudo-second-order kinetic and pseudo-first-order kinetic expression. Fe2+ from ZVI oxidization could improve the efficient generation of , which obviously boosted ZVI corrosion. The production of could be manipulated by oxalic acid, ethylenediaminetetraacetic acid (EDTA), citric acid and phosphates through controlling the concentration of dissociative Fe2+, leading to an obvious repression on As (III) removal. The fitting of X-ray absorption fine structure (XAFS) spectra illustrated that the interatomic distance of As-O shell was located between As(III)-O and As(V)-O shell and external Fe2+ could promote the oxidation of As (III) to As (V) from 35.6% in 1.0 min-44.5% in 10.0 min. Goethite as the main component of iron oxyhydroxides might play a significant role of As (III) adsorption in Fe2+-SP-ZVI system. These findings are crucial for knowing the fate and transport of arsenic under permeable reactive barriers.

An implantable multifunctional neural microprobe for simultaneous multi-analyte sensing and chemical delivery.

A multifunctional chemical neural probe fabrication process exploiting PDMS thin-film transfer to incorporate a microfluidic channel onto a silicon-based microelectrode array (MEA) platform, and enzyme microstamping to provide multi-analyte detection is described. The Si/PDMS hybrid chemtrode, modified with a nano-based on-probe IrOx reference electrode, was validated in brain phantoms and in rat brain.

Involute the reactivity of persulfate with zero-valent iron for enhanced removal of arsenic (V) in aspect involvement of Fe2+ or Fe3.

Being a fundamental issue regarding sewage treatment, heavy metals removal from industrial effluents has been subject to intense scrutiny in both the academic and practical worlds. The removal of pentavalent arsenic (As(V)), one of the most poisonous pollutants, was investigated using a sodium persulfate and iron powder system activated by ferrous ions (Fe2+-ZVI-PS). As(V) could be effectively removed by an Fe2+-ZVI-PS system in a timely fashion (minute scale) with high removal rates (more than 90.0%) over a wide range of pH (1-9) and concentration (20-100 mg/L). The removal of As(V) by the Fe2+-ZVI-PS system integrated favorably with the pseudo-second-order reaction kinetics. Researches on X-ray photoelectron spectroscopy (XPS) demonstrated that the Fe2+-ZVI-PS system enables the removal of As(V) through the process of co-precipitation and adsorption. Our findings thus emphasized that the Fe2+-ZVI-PS system should be an effective trigger to purifying arsenic from the environment. Our results indicated that the Fe2+-ZVI-PS system could be an effective candidate for remediation of arsenic in the environment.

Intracellular Photothermal Delivery for Suspension Cells Using Sharp Nanoscale Tips in Microwells.

Efficient intracellular delivery of biomolecules into cells that grow in suspension is of great interest for biomedical research, such as for applications in cancer immunotherapy. Although tremendous effort has been expended, it remains challenging for existing transfer platforms to deliver materials efficiently into suspension cells. Here, we demonstrate a high-efficiency photothermal delivery approach for suspension cells using sharp nanoscale metal-coated tips positioned at the edge of microwells, which provide controllable membrane disruption for each cell in an array. Self-aligned microfabrication generates a uniform microwell array with three-dimensional nanoscale metallic sharp tip structures. Suspension cells self-position by gravity within each microwell in direct contact with eight sharp tips, where laser-induced cavitation bubbles generate transient pores in the cell membrane to facilitate intracellular delivery of extracellular cargo. A range of cargo sizes were tested on this platform using Ramos suspension B cells with an efficiency of >84% for Calcein green (0.6 kDa) and >45% for FITC-dextran (2000 kDa), with retained viability of >96% and a throughput of >100 000 cells delivered per minute. The bacterial enzyme ß-lactamase (29 kDa) was delivered into Ramos B cells and retained its biological activity, whereas a green fluorescence protein expression plasmid was delivered into Ramos B cells with a transfection efficiency of >58%, and a viability of >89% achieved.

Ionic-surfactant-mediated electro-dewetting for digital microfluidics.

The ability to manipulate droplets on a substrate using electric signals1-known as digital microfluidics-is used in optical2,3, biomedical4,5, thermal6 and electronic7 applications and has led to commercially available liquid lenses8 and diagnostics kits9,10. Such electrical actuation is mainly achieved by electrowetting, with droplets attracted towards and spreading on a conductive substrate in response to an applied voltage. To ensure strong and practical actuation, the substrate is covered with a dielectric layer and a hydrophobic topcoat for electrowetting-on-dielectric (EWOD)11-13; this increases the actuation voltage (to about 100 volts) and can compromise reliability owing to dielectric breakdown14, electric charging15 and biofouling16. Here we demonstrate droplet manipulation that uses electrical signals to induce the liquid to dewet, rather than wet, a hydrophilic conductive substrate without the need for added layers. In this electrodewetting mechanism, which is phenomenologically opposite to electrowetting, the liquid-substrate interaction is not controlled directly by electric field but instead by field-induced attachment and detachment of ionic surfactants to the substrate. We show that this actuation mechanism can perform all the basic fluidic operations of digital microfluidics using water on doped silicon wafers in air, with only ±2.5 volts of driving voltage, a few microamperes of current and about 0.015 times the critical micelle concentration of an ionic surfactant. The system can also handle common buffers and organic solvents, promising a simple and reliable microfluidic platform for a broad range of applications.

Flexible, multifunctional neural probe with liquid metal enabled, ultra-large tunable stiffness for deep-brain chemical sensing and agent delivery.

Flexible neural probes have been pursued previously to minimize the mechanical mismatch between soft neural tissues and implants and thereby improve long-term performance. However, difficulties with insertion of such probes deep into the brain severely restricts their utility. We describe a solution to this problem using gallium (Ga) in probe construction, taking advantage of the solid-to-liquid phase change of the metal at body temperature and probe shape deformation to provide temperature-dependent control of stiffness over 5 orders of magnitude. Probes in the stiff state were successfully inserted 2 cm-deep into agarose gel "brain phantoms" and into rat brains under cooled conditions where, upon Ga melting, they became ultra soft, flexible, and stretchable in all directions. The current 30 µm-thick probes incorporated multilayer, deformable microfluidic channels for chemical agent delivery, electrical interconnects through Ga wires, and high-performance electrochemical glutamate sensing. These PDMS-based microprobes of ultra-large tunable stiffness (ULTS) should serve as an attractive platform for multifunctional chronic neural implants.

Highly efficient and rapid removal of arsenic(iii) from aqueous solutions by nanoscale zero-valent iron supported on a zirconium 1,4-dicarboxybenzene metal-organic framework (UiO-66 MOF).

A zirconium 1,4-dicarboxybenzene metal-organic framework (UiO-66 MOF) was successfully used as a template to enhance the distribution and activity of nanoscale zero-valent iron (NZVI). MOF-NZVI showed good anti-interference ability to co-existing ions (Ca2+, Mn2+, Cu2+, H2PO4 - and SO4 2-) and organic acids (oxalic acid and citric acid). SEM and TEM analyses indicated that the MOF as a support efficiently prevent NZVI from aggregation for quick and effective removal of As(iii). Through the non-linear least-squares (NLLS) adjustment, As(iii) removal by MOF-NZVI could be well fitted by pseudo first and second order reaction kinetics, as well as the Freundlich isotherm. FTIR, XRD and XPS results verified that NZVI and iron oxyhydroxides (Fe3O4, γ-Fe2O3, γ-FeOOH and α-FeOOH) might be responsible for the effective removal of As(iii) and its oxidized product As(v) with an adsorption capacity of 360.6 mg As per g NZVI through chemical oxidation and physical adsorption. This work indicates that MOF-NZVI with good reusability and high efficiency is promising for application in As(iii)-polluted wastewater treatment.

Two Vanilloid Ligand Bindings Per Channel Are Required to Transduce Capsaicin-Activating Stimuli.

The tetrameric capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) in mammals has evolved the capability to integrate pain signal arising from harmful temperature and chemical irritants. The four repetitions of TRPV1 subunits result in an ion channel with excellent pain sensitivity, allowing this ionotropic receptor to differentiate graded injuries. We manipulated the stoichiometry and relative steric coordination of capsaicin-bound structures at the molecular level to determine the rules by which the receptor codes pain across a broad range of intensities. By introducing capsaicin-insensitive S512F mutant subunits into the TRPV1 channel, we found that binding of the first ligand results in low but clear channel activation. Maximal agonist-induced activation is already apparent in tetramers harboring two or three wild-type TRPV1 subunits, which display comparable activity to wild-type tetramer. The non-vanilloid agonist 2-aminoethoxydiphenyl borate (2-APB) differs from that of capsaicin in the TRPV1 channel opening mechanism activating all S512F-mutated TRPV1 channels. Two or more wild-type TRPV1 subunits are also required for full anandamide-induced channel activation, a cannabinoid that shares overlapping binding-pocket to capsaicin. Our results demonstrate that the stoichiometry of TRPV1 activation is conserved for two types of agonists.