Model prediction of inactivation of Aeromonas salmonicida grown on poultry in situ by intense pulsed light

The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of inactivation.In this work,chicken meat and skin inoculated with meat-borne A.salmonicida isolates were subjected to IPL treatments under different conditions.The results showed that IPL had obvious bactericidal effect in the chicken skin and thickness groups when the treatment voltage and time were 7 V combined with 5 s.In addition,the lethality curves of A.salmonicida were fitted under IPL conditions of 3.5-7.5 V.The comparison of statistical parameters revealed that the Weibull model could best fit the mortality curves and could accurately predict the mortality dynamic of A.salmonicida grown on chicken skin.And further a secondary model between the scale factor b and the treatment voltage in Weibull model was established using linear equations,which determined that the secondary model could accurately predict the inactivation of A.salmonicida.This study provides a theoretical basis for future prediction models of Aeromonas,and also provides new ideas for sterilization approaches of meat-borne Aeromonas.

Tunable phonon-photon coupling induces double magnomechanically induced transparency and enhances slow light in an atom-opto-magnomechanical system

We theoretically investigate the magnomechanically induced transparency phenomenon,Fano resonance and the slow-fast light effect in the situation where an atomic ensemble is placed inside the hybrid cavity of an optomagnomechanical system.The system is driven by dual optical and phononic drives.We show double magnomechanically induced transparency in the probe output spectrum by exploiting the phonon-photon coupling strength.Then,we study the effects of the decay rate of the cavity and the atomic ensemble on magnomechanically induced transparency.In addition,we demonstrate that effective detuning of the cavity field frequency changes the transparency window from a symmetrical to an asymmetrical profile,resembling Fano resonances.Further,the fast and slow light effects in the system are explored.We show that the slow light profile is enhanced by adjusting the phonon-photon coupling strength.This result may have potential applications in quantum information processing and communication.

Electrically switchable helicity of light driven by the spin-orbit torque effect

The revolution in information sharing is fundamentally supported by the highly efficient processing,storage,and transmission of data[1].For the latter,energy consumption continuously increases with the rapid development of information and communication technology[2].

Heterogeneous population distribution enhances resistance to wheat lodging by optimizing the light environment

Lodging is still the key factor that limits continuous increases in wheat yields today,because the mechanical strength of culms is reduced due to low-light stress in populations under high-yield cultivation.The mechanical properties of the culm are mainly determined by lignin,which is affected by the light environment.However,little is known about whether the light environment can be sufficiently improved by changing the population distribution to inhibit culm lodging.Therefore,in this study,we used the wheat cultivar“Xinong 979”to establish a low-density homogeneous distribution treatment(LD),high-density homogeneous distribution treatment(HD),and high-density heterogeneous distribution treatment(HD-h)to study the regulatory effects and mechanism responsible for differences in the lodging resistance of wheat culms under different population distributions.Compared with LD,HD significantly reduced the light transmittance in the middle and basal layers of the canopy,the net photosynthetic rate in the middle and lower leaves of plants,the accumulation of lignin in the culm,and the breaking resistance of the culm,and thus the lodging index values increased significantly,with lodging rates of 67.5%in 2020–2021 and 59.3%in 2021–2022.Under HD-h,the light transmittance and other indicators in the middle and basal canopy layers were significantly higher than those under HD,and the lodging index decreased to the point that no lodging occurred.Compared with LD,the activities of phenylalanine ammonia-Lyase(PAL),4-coumarate:coenzyme A ligase(4CL),catechol-O-methyltransferase(COMT),and cinnamyl-alcohol dehydrogenase(CAD)in the lignin synthesis pathway were significantly reduced in the culms under HD during the critical period for culm formation,and the relative expression levels of TaPAL,Ta4CL,TaCOMT,and TaCAD were significantly downregulated.However,the activities of lignin synthesis-related enzymes and their gene expression levels were significantly increased under HD-h compared with HD.A partial least squares path modeling analysis found significant positive effects between the canopy light environment,the photosynthetic capacity of the middle and lower leaves of plants,lignin synthesis and accumulation,and lodging resistance in the culms.Thus,under conventional high-density planting,the risk of wheat lodging was significantly higher.Accordingly,the canopy light environment can be optimized by changing the heterogeneity of the population distribution to improve the photosynthetic capacity of the middle and lower leaves of plants,promote lignin accumulation in the culm,and enhance lodging resistance in wheat.These findings provide a basis for understanding the mechanism responsible for the lower mechanical strength of the culm under high-yield wheat cultivation,and a theoretical basis and for developing technical measures to enhance lodging resistance.

Identifying drivers of urban landuse changes in the Wenchuan earthquake- affected area by using night-time light data

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken areas.However,spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation data.This research,leveraging night-time light remote sensing imagery and land cover data,conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquake-prone areas.It introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these regions.To validate the proposed methods,the 2008 Wenchuan earthquake-affected area in China was selected as a representative study area.The results indicated that the average Digital Number(DN)values in socio-economically impacted areas showed a trend of rising,falling,and then rising again after the earthquake.DN values in three types of damaged areas including Type Ⅱ,Type Ⅲ,and Type Ⅳ exceeded pre-earthquake levels.The analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake,whereas factors such as slope,elevation,lithology,and faults had a stronger influence on urban land expansion after the earthquake.It can be seen that,in view of the differences in the natural conditions of regions for post-disaster reconstruction,the local government need to actively adjust and adapt to urban spatial planning,so as to leverage the scale effect of large-scale inputs of funds,facilities,human resources and other factors after the disaster,thus enhancing resilience and recovery efficiency in response to disaster impacts.

Topological slow light and rainbow trapping of surface wave in valley photonic crystal bounded by air

Topological slow light and rainbow trapping tend to rely on large-scale interface structure in previous research work,which have restricted further miniaturization.In this work,we propose a method to realize slow light and rainbow trapping at the zigzag edge of a single valley photonic crystals(VPCs)bounded by air,which is very different from previous studies where rainbow trapping is supported at the interface separating two VPCs with inversion symmetry.By constructing the VPC–air boundaries and VPC–VPC interfaces experimentally,we have observed the topologically protected rainbow trapping simultaneously at the external and internal boundary.This work provides a feasible platform for the miniaturized optical communication devices such as optical buffers,optical storage and optical routing.

Robust Facial Biometric Authentication System Using Pupillary Light Reflex for Liveness Detection of Facial Images

Pupil dynamics are the important characteristics of face spoofing detection.The face recognition system is one of the most used biometrics for authenticating individual identity.The main threats to the facial recognition system are different types of presentation attacks like print attacks,3D mask attacks,replay attacks,etc.The proposed model uses pupil characteristics for liveness detection during the authentication process.The pupillary light reflex is an involuntary reaction controlling the pupil’s diameter at different light intensities.The proposed framework consists of two-phase methodologies.In the first phase,the pupil’s diameter is calculated by applying stimulus(light)in one eye of the subject and calculating the constriction of the pupil size on both eyes in different video frames.The above measurement is converted into feature space using Kohn and Clynes model-defined parameters.The Support Vector Machine is used to classify legitimate subjects when the diameter change is normal(or when the eye is alive)or illegitimate subjects when there is no change or abnormal oscillations of pupil behavior due to the presence of printed photograph,video,or 3D mask of the subject in front of the camera.In the second phase,we perform the facial recognition process.Scale-invariant feature transform(SIFT)is used to find the features from the facial images,with each feature having a size of a 128-dimensional vector.These features are scale,rotation,and orientation invariant and are used for recognizing facial images.The brute force matching algorithm is used for matching features of two different images.The threshold value we considered is 0.08 for good matches.To analyze the performance of the framework,we tested our model in two Face antispoofing datasets named Replay attack datasets and CASIA-SURF datasets,which were used because they contain the videos of the subjects in each sample having three modalities(RGB,IR,Depth).The CASIA-SURF datasets showed an 89.9%Equal Error Rate,while the Replay Attack datasets showed a 92.1%Equal Error Rate.

A light field measurement system through PSF estimation by a morphology-based method

Light field imaging technology can obtain three-dimensional(3D)information of a test surface in a single exposure.Traditional light field reconstruction algorithms not only take a long time to trace back to the original image,but also require the exact parameters of the light field system,such as the position and posture of a microlens array(MLA),which will cause errors in the reconstructed image if these parameters cannot be precisely obtained.This paper proposes a reconstruction algorithm for light field imaging based on the point spread function(PSF),which does not require prior knowledge of the system.The accurate PSF derivation process of a light field system is presented,and modeling and simulation were conducted to obtain the relationship between the spatial distribution characteristics and the PSF of the light field system.A morphology-based method is proposed to analyze the overlapping area of the subimages of light field images to identify the accurate spatial location of the MLA used in the system,which is thereafter used to accurately refocus light field imaging.A light field system is built to verify the algorithm’s effectiveness.Experimental results show that the measurement accuracy is increased over 41.0%compared with the traditional method by measuring a step standard.The accuracy of parameters is also improved through a microstructure measurement with a peak-to-valley value of 25.4%and root mean square value of 23.5%improvement.This further validates that the algorithm can effectively improve the refocusing efficiency and the accuracy of the light field imaging results with the superiority of refocusing light field imaging without prior knowledge of the system.The proposed method provides a new solution for fast and accurate 3D measurement based on a light field.

Hepatomegaly and jaundice as the presenting symptoms of systemic light-chain amyloidosis: A case report

BACKGROUND Light chain(AL)amyloidosis is a plasma cell dyscrasia characterized by the pathologic production and extracellular tissue deposition of fibrillar proteins derived from immunoglobulin AL fragments secreted by a clone of plasma cells,which leads to progressive dysfunction of the affected organs.The two most commonly affected organs are the heart and kidneys,and liver is rarely the dominant affected organ with only 3.9%of cases,making them prone to misdia-gnosis and missed diagnosis.CASE SUMMARY A 65-year-old woman was admitted with a 3-mo history of progressive jaundice and marked hepatomegaly.Initially,based on enhanced computed tomography scan and angiography,Budd-Chiari syndrome was considered and balloon dilatation of significant hepatic vein stenoses was performed.However,addi-tional diagnostic procedures,including liver biopsy and bone marrow-exami-nation,revealed immunoglobulin kapa AL amyloidosis with extensive liver involvement and hepatic vascular compression.The disease course was progre-ssive and fatal,and the patient eventually died 5 mo after initial presentation of symptoms.CONCLUSION AL amyloidosis with isolated liver involvement is very rare,and can be easily misdiagnosed as a vascular disease.

Systematic Identification of Acer rubrum bZIP Transcription Factors and Their Potential Role in Anthocyanin Accumulation under Low Temperature with Light

Acer rubrum is an important garden color-leafed plant.Its leaves will turn red in autumn,which is of great orna-mental value.The leaf color change in Acer rubrum is closely associated with anthocyanins accumulation.In anthocyanin synthesis and accumulation,various transcription factor families play significant regulatory roles,including the basic(region)leucine zipper(bZIP).However,there is no report on the systematic identification and functional analysis of the bZIPs in Acer rubrum.In this study,137 bZIPs distributed on 29 chromosomes of Acer rubrum were identified and renamed according to their locations on the chromosomes.According to the constructed bZIP phylogenetic tree of Arabidopsis thaliana and Acer rubrum,bZIPs were divided into 13 groups.Two pairs of bZIP genes were involved in tandem duplication,and 106 segmental duplication gene pairs were found.Cis-acting elements in the promoter region of these bZIP genes were analyzed.The results of promoter analysis showed that many elements were closely related to light conditions,hormone responses,and abiotic stress factors.Among them,the cis-acting elements related to light response were most abundant and prominent.The results of anthocyanin determination showed that anthocyanin contents in the leaves of Acer rubrum increased significantly under low temperature with light.In addition,gene expression analysis showed that compared to other ArbZIPs,ArbZIP137,ArbZIP136,ArbZIP114,ArbZIP130,and ArbZIP14 showed a more pronounced increase in gene expression both under low-temperature conditions and under light conditions.From the correlation analysis,there was a high correlation between ArbZIPs and several anthocyanin-regulated transcription factors,including ArMYBs,ArbHLH and ArWD40s.Conclusively,the bZIP genes in Acer rubrum were identified and analyzed,providing a foundational basis for future studies on their function and significantly enhancing our understanding of the color mechanism of Acer rubrum.

Regulation of circadian physiology and behavior by light in mammals:entrainment and masking

manifestation of circadian rhythms.The modern use of electric lights alters environmental lighting,leading to light exposure at inappropriate times to disturb circadian homeostasis for both human and wildlife.The light“pollution”and voluntary activities such as night shift work and transmeridian travelling have adverse consequences such as mood and metabolic disorders in humans.On the other hand,insufficient light exposure decreases neurotransmission from the locus ceruleus and dorsal raphe,leading to seasonal and nonseasonal affective disorders,while properly timed bright light is beneficial to mood and cognition.Given the critical and complex roles of light in mammalian physiology and behavior,it is essential to understand the underlying mechanisms.In this review,we discuss the neural mechanisms through which light regulates and dysregulates circadian rhythms in mammals.

Multi-View Structured Light 3D Measurement System

Vision-based measurement technology benefits high-quality manufacturers through improved dimensional precision,enhanced geo-metric tolerance,and increased product yield.The monocular 3D structured light visual sensing method is popular for detecting online parts since it can reach micron-meter depth accuracy.However,the line-of-sight requirement of a single viewpoint vision system often fails when hiding occurs due to the object’s surface structure,such as edges,slopes,and holes.To address this issue,a multi-view 3D structured light vi-sion system is proposed in this paper to achieve high accuracy,i.e.,Z-direction repeatability,and reduce hiding probability during mechani-cal dimension measurement.The main contribution of this paper includes the use of industrial cameras with high resolution and high frame rates to achieve high-precision 3D reconstruction.Moreover,a multi-wavelength(heterodyne)phase expansion method is employed for high-precision phase calculation.By leveraging multiple industrial cameras,the system overcomes field of view occlusions,thereby broadening the 3D reconstruction field of view.Finally,the system achieves a Z-axis repetition accuracy of 0.48µm.

Protective and Regenerative Efficacy of a Plant Oil-Based Day and Night Cream: Investigated by a Novel Approach to Reveal the Impact of Blue Light Irradiation on Epidermal Barrier Integrity and Lipid Matrix

In recent years, the harmful effects of blue light (400 - 500 nm) as a component of visible light (400 - 700 nm) have increasingly gained attention of science, industry, and consumers. To date, only a few in vivo test methods for measuring the effects of blue light on the skin have been described. A direct measurement method that can detect the immediate effects of blue light on the epidermal permeability barrier (EPB) is still lacking. In this study, we present a new methodological approach that can be used to investigate both the protective and regenerative effects of cosmetic products on the EPB after blue light irradiation. In a study with 14 female volunteers, it was investigated whether the regular application of an O/W emulsion (day cream) can strengthen and protect the epidermal barrier against damaging blue light radiation of 60 J/cm2 (protective study design) and also whether a disruption of the epidermal barrier caused by blue light radiation is restored faster and better by the regular application of another O/W emulsion (night cream) than in product-untreated skin (regenerative study design). The two O/W emulsions are different in plant oil, active ingredient composition and texture. The seven-day treatment with the day cream initially led to a significant increase in the normalized lipid lamellae length in the intercellular space, whereas the irradiation with blue light after 24 hours led to a significant decrease in the lipid lamellae length in the untreated test area, but not in the area previously treated with the product. Regarding the regenerative study design, a two-day treatment with the night cream was able to restore a blue-light-induced decrease in lipid lamellae length in the intercellular space. In summary, with the study designs presented here, the protective and regenerative effect of two cosmetic products could be demonstrated for the first time on the integrity of the EPB after blue light irradiation and the data showed that the Lipbarvis® method is suitable for investigating the damaging effects of blue light on the EPB in vivo.

Tracing of natural gas migration by light hydrocarbons:A case study of the Dongsheng gas field in the Ordos Basin,NW China

Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents.

PHOTOPOLYMERIZATION INITIATED BY DIMETHYLAMINOCHALCONE/DIPHENYLIODONIUM SALT COMBINATION SYSTEM SENSITIVE TO VISIBLE LIGHT

Several dimethylamino-substituted chalcone (i .e. dimethylaminobenzal acetophenone) (DBA) derivatives with intramolecular charge transfer transition character were used as visible light sensitizers for radical photopolymerization initiated by iodonium salt (DPIO). Initiating radical species is produced from DBA sensitized photolysis of DPIO through the single electron transfer, accompanying the bleaching of DBA, The activity of DBA decreases as a function of substituent attached to phenyl ring in the order: DBA-2 (OCH_3) >DBA-1(H)> DBA-3 (Cl). The kinetic study on photopolymerization of MMA was carried out in CH_3CN solution at 30 ℃ by dilatometry. The polymerization rate was determined to be proportional to the concentration with exponents of 0.42, 0.25 and 0.86 for DPIO, DBA-1 and MMA, respectively.

Smart Street Lighting Control and Monitoring System for Electrical Power Saving by Using VANET

The huge amount of electrical power of many countries is consumed in lighting the streets. However, vehicles pass with very low rate in specific periods of time and parts of the streets are not occupied by vehicles over time. In this paper, we propose a system that automatically switches off the light for the parts of the streets having no vehicles and turns on the light for these parts once there are some vehicles that are going to come. Logically, this system may save a large amount of the electrical power. In addition, it may increase the lifetime of the lamps and reduce the pollutions. This system automatically controls and monitors the light of the streets. It can light only the parts that have vehicles and help on the maintenance of the lighting equipments. Vehicular Ad-Hoc Networks (VANET) make it possible to propose such system. VANET enables the possibility to know the presence of vehicles, their locations, their directions and their speeds in real time. These quantities are what are needed to develop this system. An advantage of using VANET is that there is no need to use specific network and equipments to design the system, but VANET infrastructure will be used. This decreases the cost and speed up the deployment of such system. This paper focuses on the proposal of different possible architectures of this system. Results show that the saved energy may reach up to 65% and an increase of the lifetime of the lamps of 53%.

Intelligent Solar Chasing Street Light System Design and Fabrication Summaries

This project adopts an advanced microcontroller as the core control unit,which accurately commands the servo drive,realizes the real-time light chasing and charging function of the solar panel,and effectively manages the power supply system of the street light.At the same time,the system is able to continuously monitor the operation status of the servo within the range of 0°to 180°to ensure that it is trouble-free and not offline.The hardware system construction consists of five modules:a power module,solar panel module,servo module,street light module,and Organic Light-Emitting Diode(OLED)display module.Each module works together to support the stable operation of the whole system.The system workflow is to accurately determine the direction of the light source by collecting real-time light intensity data through four precision photoresistors.Subsequently,the microcontroller intelligently controls the helm module based on these data to drive the solar panel to rotate within a range of 180°to accurately track the sun’s orientation.The street light provides two lighting modes,automatic and manual,to meet the needs of different scenarios.During the daytime,the solar panels work actively to monitor and collect solar energy efficiently in real-time,meanwhile,when night falls,the solar panels switch to standby mode and the streetlights light up automatically,illuminating the road ahead for pedestrians.Compared with the traditional solar street lights on the market,the intelligent solar light chasing road system introduced in this project has significant advantages.Its unique light-chasing algorithm enables the solar panel to continuously track the light source from sunrise to sunset,thus significantly improving the charging efficiency.Compared with traditional street lights,the biggest advantage of this project is the proposed light-chasing algorithm,which can always charge from sunrise until sunset,making the charging efficiency increase by 38%to 47%.The charging efficiency is 20%to 38%higher than that of traditional street lamps.Simultaneously,the biggest advantage of this project is that the power storage capacity is higher than 35%of the traditional solar street light.Bringing users a more durable and stable lighting experience.

Distributed Intelligent Lighting System by Performing New Model for Illuminance and Color Temperature in the Workplace

A new approach has been proposed to improve the performance of the in-telligent lighting system by estimating personal illuminance and desired color temperature at the workplace. We are considering the problem of using the sensing devices manually for the intelligent lighting system. The lighting control system has not become useful without sensing devices to measure the provided illuminance and color temperature. In this paper, we have used the property of light for the color temperature to estimate the level of color temperature for each user at the workplace. The new method will give personal illuminance for each user at the workplace and decrease the power consumption of the environment as well. As a result, the proposed method of the intelligent lighting system has realized the target of illuminance and color temperature for each user at the workplace by adapting dimming levels using illuminance sensing information for each user. Thus, the energy of the workplace has reduced by using a distributed luminance to realize the target for each user.

Suppressing neuroinflammation using the near-infrared light emitted by (Sr,Ba)Ga_(12)O_(19): Cr^(3+) phosphor

Neurodegenerative diseases,such as Parkinson’s and Alzheimer’s diseases,affect the elderly worldwide and will become more prevalent as the global population ages.Neuroinflammation is a common characteristic of neurodegenerative diseases.By regulating the phenotypes of microglia,it is possible to suppress neuroinflammation and,in turn,help prevent neurodegenerative diseases.We report a noninvasive photonic approach to regulating microglia from overexcited M1/M2 to the resting M0 phenotype using a special near-infrared(NIR)light emitted by the SrGa_(12)O_(19)∶Cr^(3t) phosphor.The absorbance and internal and external quantum efficiencies of the optimal SreGa_(0.99)Cr_(0.01)_(12)O_(19) phosphor synthesized at 1400℃ for 8 h using 1%H_(3)BO_(3) t 1%AlF3 as flux are 53.9%,99.2%,and 53.5%;the output power and energyconversion efficiency of the LED device packaged using the optimal SrGa_(12)O_(19): Cr^(3+) phosphor driven at 20 mA reach unprecedentedly 19.69 mW and 37.58%,respectively.The broadband emission of the NIR LED device covers the absorption peaks of cytochrome c oxidase well,and the NIR light can efficiently promote the proliferation of microglia,produce adenosine triphosphate(ATP),reverse overexcitation,alleviate and inhibit inflammation,and improve cell survival rate and activity,showing great prospects for photomedicine application.

Measurement of the Average Molecular Weight of Cotton Cellulose Crosslinked by a Polycarboxylic Acid at Different pH Using Multiple Angle Light Scattering Photometer in a DMAc/LiCl Solvent System

Durable press finishing of cotton fabrics with polycarboxylic acid increases fabric wrinkle-resistance at the expense of its mechanical strength. Severe tensile strength loss is the major disadvantage for wrinkle resistant cotton fabrics.Tensile strength loss of cotton fabric crosslinked by a polycarboxylic acid can be attributed to depolymerization and crosslink of cellulose molecules. Measurement of the molecular weight of cotton fabric before and after crosslinked by polycarboxylic acids can offer a possibility of direct understanding of the depolymerization. In this research, amultiple angle laser light scattering photometer was used todetermine the absolute molecular weight of cotton fabric treated with BTCA at different pH and then hydrolyzed with 0. 5 M NaOH solution at 50℃ for 144 h. The results indicate that average molecular weights of cotton fabric treated with polycarboxylic acids at different pH are almost the same.