Pressure-induced color change arising from transformation between intra-and inter-band transitions in LuH_(2±x)N_(y)

The pressure-induced color change in the nitrogen-doped lutetium hydride has triggered extensive discussions about the underlying physics and potential applications.Here,we study the optical response of LuH_(2±x)N_(y)in a broad frequency range at ambient pressure and its evolution with pressure in the visible spectral range.The broad-band optical spectra at ambient pressure reveal a Drude component associated with intra-band electronic transitions and two Lorentz components(L1 and L2)arising from inter-band electronic transitions.The application of pressure causes a spectral weight transfer from L1 to the Drude component,leading to a blue shift of the plasma edge in the reflectivity spectrum alongside a reduction of the high-frequency reflectivity.Our results suggest that the pressure-induced color change in LuH_(2±x)N_(y)is closely related to the transformation between intra-and inter-band electronic transitions,providing new insights into the mechanism of the pressure-induced color change in LuH_(2±x)N_(y).

Pressure induced color change and evolution of metallic behavior in nitrogen-doped lutetium hydride

By applying pressures up to 42 GPa on the nitrogen-doped lutetium hydride(LuH2_(±x)N_(y)),we have found a gradual change of color from dark-blue to pink-violet in the pressure region of about 12 to 21 GPa.The temperature dependence of resistivity under pressures up to 50.5 GPa shows progressively optimized metallic behavior with pressure.Interestingly,in the pressure region for the color change,a clear decrease of resistivity is observed with the increase of pressure,which is accompanied by a clear increase of the residual resistivity ratio(RRR).Fitting to the low temperature resistivity gives exponents of about 2,suggesting a Fermi-liquid behavior in the low temperature region.The general behavior in a wide temperature region suggests that the electron-phonon scattering is still the dominant one.The magnetoresistance up to 9 T in the state under a pressure of 50.5 GPa shows an almost negligible effect,which suggests that the electric conduction in the pink-violet state is dominated by a single band.It is highly desired to have theoretical efforts in understanding the evolution of color and resistivity in this interesting system.

Identification and effective regulation of scarb1 gene involved in pigmentation change in autotetraploid Carassius auratus

The autotetraploid Carassius auratus(4nRR,4n=200,RRRR)is derived from whole-genome duplication of Carassius auratus red var.(RCC,2n=100,RR).In the current study,we demonstrated that chromatophores and pigment changes directly caused the coloration and variation of 4nRR skin(red in RCC,brownish-yellow in4nRR).To further explore the molecular mechanisms underlying coloration formation and variation in 4nRR,we performed transcriptome profiling and molecular functional verification in RCC and 4nRR.Results revealed that scarb1,associated with carotenoid metabolism,underwent significant down-regulation in 4nRR.Efficient editing of this candidate pigment gene provided clear evidence of its significant role in RCC coloration.Subsequently,we identified four divergent scarb1 homeologs in 4nRR:two original scarb1 homeologs from RCC and two duplicated ones.Notably,three of these homeologs possessed two highly conserved alleles,exhibiting biased and allelespecific expression in the skin.Remarkably,after precise editing of both the original and duplicated scarb1homeologs and/or alleles,4nRR individuals,whether singly or multiply mutated,displayed a transition from brownishyellow skin to a cyan-gray phenotype.Concurrently,the proportional areas of the cyan-gray regions displayed a gene-dose correlation.These findings illustrate the subfunctionalization of duplicated scarb1,with all scarb1genes synergistically and equally contributing to the pigmentation of 4nRR.This is the first report concerning the functional differentiation of duplicated homeologs in an autopolyploidfish,substantiallyenrichingour understanding of coloration formation and change within this group of organisms.

Hormonal control of seasonal color change in female spiny-footed lizards:an observational and experimental approach

Breeding coloration of females often signals aspects of their reproductive status,suggesting a link between color and sex steroid hormones.In this study,we examined the relationships between 2 sex steroid hormones(progesterone and p-estradiol)and reproductive coloration in female spinyfooted lizards Acanthodactylus erythrurus.We first explored natural variation in female plasma hormone levels and coloration during their reproductive cycle,p-estradiol was negatively related to brightness and positively related to red saturation,whereas progesterone was not significantly related to coloration.After identifying key relationships,plasma hormone concentrations were manipulated by creating 3 experimental female groups(p-estradiol-treated,progesterone-treated,and control),and the effects on coloration were monitored,p-estradiol-treated females,in which there was a rise in both p-estradiol and progesterone levels,lost their red coloration earlier than females in the other 2 experimental groups,whereas progesterone treatment had no significant effect on female coloration.Our results suggest that high levels of either p-estradiol alone or(3-estradiol together with progesterone trigger the loss of red coloration in female spiny-footed lizards,and that progesterone alone does not affect coloration.We hypothesize that changes in female breeding color might be regulated by(3-estradiol in species in which conspicuous coloration is displayed before ovulation,and by progesterone in species in which this color is displayed during gravidity.

Change Color Effect and Spectral Properties of Gold Nanoparticle-cationic Surfactants System

The change color effect of gold nanoparticle solutions was studied by means of resonance scattering and absorption spectrometry and scan electron microscopy. The red Au nanoparticles with a size of 10 nm exhibit a resonance absorption peak and a resonance scattering peak all at 525 nm. After some inorganic electrolyte was added to a red Au nanoparticles solution, the color of the solution became blue and the absorbance at (600_700) nm was significantly increased. The ratio of the concentration of monovalent cations, at which the resonance scattering of the system at 525 nm is maximal to that of divalent cations, is in the range of 100∶1_100∶1.8. It is in good agreement with the Schulze-Hardy rule of the coagulation value of electrolyte. After adding some cationic surfactants to the above solution, the color of the solution is in deep blue, with two resonance absorption peaks at 550 and 680 nm, and a greatly enhanced resonance scattering peak at 525 nm. The experiments demonstrate that the stronger the hydrophobicity of the cationic surfactant is, the stronger the change color effect of the Au nanoparticle solution promoted by cationic surfactant is. The change color effect of Au nanoparticle solution is resulted from the increased diameter of Au nanoparticles, and the changes of resonance absorption peak and resonance scattering.

Gamma induced changes in Makrofol/CdSe nanocomposite films

We applied an ex-situ casting procedure to prepare a nanocomposite(NCP)from Makrofol polycarbonate(PC)and CdSe nanoparticles.The CdSe nanoparticles were prepared by a thermolysis procedure in the presence of N_(2) gas flow.Rietveld refinement of x-ray data illustrated that the CdSe adopts a cubic zinc blend structure of 6.057 A lattice parameter and 2 nm typical grain size.Samples from the prepared NCP were exposed to γ dosages(20 kGy-250 kGy).The modifications induced in the NCP films owing to γ dosages have been studied.Theγirradiation(50 kGy-250 kGy)causes crosslinks that reduce the optical bandgap from 4.15 eV to 3.81 eV,associated with an increase in dielectric parameters and refractive index.This is attributed to an increase in the mass fraction of the disordered regions as specified by x-ray diffraction.The PC-CdSe NCP was found to have a reaction to color modification which makes it suitable for saleable reproduction on a printing press.

Effect of Aluminum Oxide on the Alteration Perceived Color ofDark Dental Substrates

The objective of the present research was to determine the degree of masking which occurs when 0.2 mm densely sintered aluminum oxide is placed over substrates of various colors. 20 lighter and 20 darker substrates were made from a mixture of dental amalgam and resin in an aluminum mold. The thin (0.2 mm) disks of densely sintered aluminum oxide were placed on the various substrates. The color changes after masking by these disks were recorded using a Minolta Chroma Meter Ⅱ. The results showed that the color (L *, a *, b *) changes after placing the disks over the substrates were obvious and lead to statistical significant differences (P<0.000 1) in ΔE, ΔL *, Δa *, Δb *. The masking ability was more pronounced with the aluminum oxide over the dark substrates than the light substrates.

Variation in phenolic composition and color features of red wine during vinification

The compositions and contents of phenolic components during the three periods(alcoholic fermentation,malolactic fermentation and aging process)of wine making by Cabernet Sauvignon were analyzed by high performance liquid chromatography.The color parameters of the wine were also determined by CIELab method.Correlation analysis and principal component analysis were adopted to analyze the correlation between phenolic content and color parameters.In fermentation and aging periods,anthocyanins and other phenolic components in wine increased at first,and before the end of malolactic fermentation,the contents reached the highest,and later experienced a downward trend,then contents change showed a stable trend in the later stage of storage.During the whole wine-making,anthocyanins had significant correlation with CIELab parameter a*and anthocyanin malvidin-3-O-glucoside was mainly observed to present a large impact on a*in aging period,causing the red color change of wine.Other phenolic components affected the CIELab parameters a*,b*and L*differently.Statistical analysis about the color parameters and 15 phenolic components revealed correlations between the color properties and detectable phenolic contents.

Development,Characterization and Application of a Three-Layer Intelligent pH-Sensing Indicator Based on Bromocresol Green(BCG)for Monitoring Fish Freshness

As a novel food quality monitoring technology,intelligent freshness indicator has received wide attention in recent years.However,its poor safety and stability are the main problems hindering its practical application.Hence a new pH-sensing indicator based on bromocresol green(BCG)was developed in this study for nondestructive and real-time monitoring the freshness of marine fishes.The indicator was designed with a three-layer structure,using the polytetrafluoroethylene(PTFE)membrane with high hydrophobicity and air permeability as the inner layer to isolate the moisture in the package,BCG-coated filter paper as the colorchanging layer to indicate the freshness of fish,and a transparent unidirectional permeable(TUP)membrane with moisture resistance as the out layer to isolate the moisture in the environment.This contributed to weaken the influence of humidity and prevent dye migration,so as to improve the accuracy and safety of the indicator.Therefore,a highly sensitive and distinguished color variation response to trimethylamine(TMA)standard solution with different concentrations was observed on the indicator.Additionally,the indicator showed a high color stability at different storage temperatures up to 14 days with total color differences(ΔE)less than 5.0.The indicator presented visible color variations from yellow to green then eventually to blue when applied to monitor the freshness of sea bass and salmon stored at 4℃,implying that fish was spoiled.Meanwhile,indicatorsΔE value was significantly positively correlated with total volatile basic nitrogen(TVB-N)and total viable count(TVC)in sea bass and salmon samples.Thus,the pH-sensing indicator can be applied as a cost-effective and promising intelligent indicator for monitoring fish freshness.

Changes in color and rheological behavior of pineapple concentrate through various evaporation methods

The objective of this study was to investigate the effect of various concentration methods namely microwave vacuum evaporation(MVE),microwave heating evaporation(MHE),and rotary vacuum evaporation(RVE)on the concentrate change,the kinetic of color degradation,and the rheological behavior of pineapple juice.The concentrated behavior of pineapple juice from the experimental data of concentration rate was fitted with three types of exponential models for evaluating a suitable prediction.The four-parameter exponential model was found to agreeably explain the concentrated change of pineapple juice during each concentration methods.The Kinetics of color change during concentration processes was evaluated.The color changing from three different evaporations was measured by lightness values(L*),redness values(a*)and yellowness(b*)values,total color difference(TCD)and brown pigment formation index(A420).The result indicated that the change in Hunter parameters,L*and b*,fitted well with the first-order kinetic model while a*,TCD,and Browning index followed the zero-order kinetic model.The observed apparent viscosities(μa)of pineapple concentrate at 55-85℃through the three different evaporation methods were also measured.In relation to temperature and shear rate,the viscosity decreased as these two parameters increased,for all concentrated pineapple juice.On comparing the values ofμa of pineapple concentrate from different concentration methods,pineapple concentrate from MHE has higher values than those from MVE and RVE.The Duncan test,applied to the experimental results,indicates no significant difference in theμa of pineapple juice concentrate by MVE and by RVE.

Bioinspired multichannel colorful encryption through kirigami activating grating

Optical encryption,exploiting degrees of freedom of light as parameters to encode and decode information,plays an indispensable role in our daily life.Responsive structural color materials can give real-time visible feedback to external stimuli and provide ideal candidates for optical encryption.However,the development of existing responsive structural color materials is hindered by poor repeatability and long feedback time.Meanwhile,there are only few strategies to exploit structural colors in multichannel information encryption.Herein,bioinspired by the structural color variation due to a change in angle arising from the movement of animal’s scales or feathers,we developed a general multichannel information encryption strategy using a two-dimensional deformable kirigami arranging orientations of the grating arrays by design.The kirigami grating sheet shows rapid,repeatable,and programmable color change.This strategy utilizes the topological space deformation to guide the change of optical property,which suggests new possibilities for spatial and spectral encryption as well as mechano-sensing and camouflage.

Detection of NO_2 Based on 4-Carboxyl-4′-hydroxy Azobenzene and Its Cu(II) Complex

An organic ligand and its Cu（II） complex formulated as （C13HloN203）·5H2O （H2L·5H2O, 1） and Cu（HL）2（phen）·0.125H2O （2, H2L = 4-carboxyl-4′-hydroxy azobenzene, phen = 1,10-phenanthroline） have been synthesized and structurally characterized by single-crystal X-ray diffraction. In the two compounds, H2L and HL exhibit a trans-conformation. Complex 2 shows a mononuclear Cu（Ⅱ） structure with the hydroxyl group of HL uncoordinated. Complex 2 is assembled into a three-dimensional （3D） supramolecular architecture by hydrogen bonds and π-π stacking interactions. H2L and compound 2 can detect NO2 via reversible and irreversible color changes, respectively. The mechanism for the color changes is investigated.

Observation on Culture Characteristics of Mycoplasma bovis with Four Different Antigen Quantification Methods

[Objective] The paper was to explore the antigen harvest time of Mycoplasrna bovis and the antigen quantification alternative method. [Method] M. bovis 08M strain was inoculated in the Thiaueourt＇s medium containing 10% horse serum. Four growth curves were plotted by simultaneously measuring color change units （CCU）, colony forming units （CFU）, protein concentration and nucleic acid levels within 110 h. [ Result] The growth of M. bovis was divided into four phases： the longarithmie phase appeared after being cultured for 10 h; the stationary phase appeared at 30 h with the highest number of viable cells up to 1. 0× 108 CCU/mL and 7.7 × 107 CCU/mL, respectively; and the decline phase started at 75 h. The protein concentration afM. bov/s increased rapidly from 15 to 35 h, reached 72.06 μg/mL at 35 h, then maintained at 53.38 - 70.65 μg/mL. The nucleic acid levels of M. bov/s increased rapidly from 15 h, and the cycle threshold （Ct） values were maintained between 15, 32 and 17.84 after 25 h. [ Conclusion] There was a good correlation between the protein concentration and variable count of M. bov/s at the early stationary phase, which was the best time period to harvest antigen. The protein concentration determination could be an alternative method to quantify antigen content of M. bovis when preparing inactivated M. boviz vaccine. Key words Mycoplasma boyis; Antigen quantification; Color change units; Colony forming units; Protein concentration; Nucleic acid content

Research on Relationships between the Pigment of Dunhuang Mogao Grottoes Frescoes and Ecological Microorganism

Dunhuang Mogao Grottoes is one of the largest art treasures in the world.She has a large number of murals,sculptures,beautiful and vivid;There are precious Buddhist scriptures,documents,noble and elegant.Spanning more than 1,600 years,the Mogao Grottoes show the world the extensive and profound Chinese culture with a long history.But over time,the murals in the Mogao Grottoes have also changed a lot.Thousands of years of wind and rain erosion,changes in the surrounding environment,and the influence of various biological communities have caused serious color changes and fading of murals in Mogao Grottoes.To slow down the color change of Dunhuang frescoes,protection measures should be taken from the perspective of ecological microorganisms.At present,Cladosporium,Planococcus,Phoma,Chaetomium,and other strains have caused serious discoloration or discoloration of murals to a certain extent.This paper studies the main color of Dunhuang frescoes,red,and summarizes the discoloration factors and mechanism of red lead.On this level,one should try to keep the murals and control the indoor temperature.Humidity,people,and other factors slow the fading of the murals.But these are often insufficient to protect the integrity of the murals,so we have conducted a review of the literature to provide an updated overview of the available evidence on the subject.

Refractive Index Change and Color Center Formation in LiYF_4 Crystal Induced by a Femtosecond Laser

The refractive index change and color centers formation in LiYF4 crystal at room temperature are induced by a femtosecond laser irradiation. A mechanism for refractive index change and color centers formation is proposed.

The Changing Colors Of Forestland Reform

Forestland use right reforms are allowing forest farmers to freely transact their land and reap new profits Hubei Province farmer Huang Huabing contracted 30 hectares of

Morphologic,Radiographic,and Stereomicroscopic Evaluation of Teeth Subjected to High Temperatures:An In vitro Forensic Study

Background:To evaluate morphologic,radiographic,and stereomicroscopic changes of teeth when subjected to specific high temperatures in both direct heat and gradual heat and to compare the changes among two heat groups and also among different types of teeth.Materials and Methods:An in vitro study was conducted on 90 healthy extracted human teeth,in which the teeth were divided into two groups.Group 1(45)was subjected to direct heat and Group 2(45)was subjected to gradual heat.Group 1 and Group 2 were further subdivided into three subgroups(A)anteriors,(B)premolars,and(C)molars each consisting of 15 teeth.Teeth were subjected to temperatures of 200°C,400°C,600°C,800°C,and 1000°C in a muffle electric furnace.The color changes were noted using the Revised Munsell soil color chart and the radiographic and stereomicroscopic changes were evaluated.The results obtained were subjected to statistical analysis.Results:Teeth in direct heat showed more destructive changes at lower temperatures,i.e.,400°C and 600°C when compared to gradual heat where changes are observed at 600°C and 800°C.Among different types of teeth,anteriors and premolars showed more changes when compared to molars.Interpretation and Conclusion:It can be concluded that dental evidence may provide clues to solve the mystery in fire investigations as dental structures are the last to be destroyed under extreme conditions,whether temperature,acid,or putrefaction.

Classification of ripening stages of bananas based on support vector machine

Non-destructive quality detection and automatic grading are important in fruit industry.The traditional way divides bananas into 7-level ripening stages based on color.This study investigated the changes of peel color at three positions of banana fingers,i.e.stalk,middle and tip.A support vector machine method was used to classify the ripening stages by color value L*,a*and b*as input data.The ripening stages were classified by 10-fold cross validation method of support vector machines with radial basis function kernel and linear function kernel.The results showed that the color change of middle position of banana finger adequately reflected the changes in banana ripening stages.a*value continuously increased from ripening stage 1 to ripening stage 7,L*and b*values increased from ripening stage 1 to ripening stage 5,and then decreased from ripening stage 5 to ripening stage 7.It was difficult to recognize the ripening stages using L*,a*and b*values individually.The accuracy of classification using support vector machine based on radial basis function kernel reached 96.5%,which was higher than that for linear function kernel.This research can provide a reference for automatic classification of banana ripening stages.

中心/刷结构颜色变化的胆甾型液晶微粒用作集成传感器

因可自发响应外部刺激而发生体积溶胀并引起其光学性能变化,胆甾型液晶微粒备受关注并在溶剂传感、防伪图案等方面具有广泛应用.胆甾型液晶微粒在溶剂中呈现中心颜色和刷结构颜色的协同变化.但由于刷结构颜色变化的复杂性,科学家们仅关注胆甾型液晶微粒中心颜色在传感中的应用,尚未有其刷结构颜色变化机理及相关应用的报道,这极大地限制了胆甾型液晶微粒的潜在应用.本文揭示了一种胆甾型液晶微粒的新型传感机理,并结合胆甾型液晶微粒中心颜色变化及刷结构颜色变化,发展了新型的溶剂传感器.与传统系统相比,该传感器提供了更为丰富的传感信息.采用反应性介晶、反应性手性掺杂剂、非反应性液晶分子和光引发剂通过微流控装置制备及光聚合得到了胆甾型液晶微粒.所制备的胆甾型液晶微粒分别在微粒的中心处和刷结构处均呈现丰富的色彩.中心反射颜色的可逆变化归因于分子萃取引起的体积收缩及溶剂溶胀引起的体积膨胀的竞争性效应.而胆甾型液晶微粒刷结构的丰富色彩归因于其在不同溶剂中的双折射效应.本文考察了中心/刷微粒在多达16种溶剂中的协同变色行为,提出了协同颜色变化的机理,并展示了这种变色聚合物微粒在多溶剂传感检测和图案显示中的应用.本文有望为开发具有可设计纳米结构的刺激响应性先进功能材料提供新的见解,拓展其在传感、防伪及图案显示等方面的技术应用.

Evaluation of fiber degree for fish muscle based on the edge feature attention net

The fiber mouthfeel of fish muscle is a highly sought-after goal for surimi gel products.The primary aim of research and development has been to quickly and accurately evaluate fiber degree for fish muscle.Therefore,based on the ResNet model,edge feature attentional mechanism was introduced to obtain the edge feature attention net (EFANet) to evaluate fiber degree for fish muscle.The EFANet was trained and tested on a dataset,which was made by collecting microscopic pictures of fish samples with different degrees of breakage.Compared with the three classic convolutional neural network (CNN) models,the EFANet emphasizes the learning of fiber texture information for fish muscle,reduces the effect of image color change,and significantly improves the detection accuracy.The average accuracy and specificity of the EFANet-50 on the testing dataset were 96.22% and 97.92%,respectively,which proved that it can effectively predict the fiber degree of fish muscle.