Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely use...Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic insights.In this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the HER.In addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during HER.These spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.展开更多
Staling is an important issue that Chinese steamed bread(CSB)may encounter during storage,which significantly affects their taste,flavor,and nutritional value.The monitoring technology for rapid aging is particularly ...Staling is an important issue that Chinese steamed bread(CSB)may encounter during storage,which significantly affects their taste,flavor,and nutritional value.The monitoring technology for rapid aging is particularly important to effectively control the aging process of CSB,reduce quality deterioration,and promote the industrial production of CSB.Raman spectroscopy has been widely used in the study of food structure and properties due to its non-destructive and high-sensitivity characteristics,particularly demonstrating unique advantages in the analysis of starch structure.This study explored the possibility of analyzing the staling of CSB using Raman spectroscopy based on hardness and moisture content.Analysis of the correlation between the hardness of CSB and the full width at half maximum(FWHM)at 480 cm^(−1)during storage was conducted,and a significant positive correlation between them was found,with R^(2)above 0.8.Besides,nine characteristic peaks of CSB samples related to starch were selected for analysis.As the moisture content of CSB decreased,the peak intensities and areas of showed an upward trend during storage,with the best correlation coefficient above 0.8 revealed by linear regression analysis.Therefore,Raman spectra could be used as a potential method for the fast prediction of CSB staling.展开更多
Au-Ag alloy nanostars based flexible paper surface enhanced Raman spectroscopy sensors were fabricated through simple nanostar coating on regular office paper,and the surface enhanced Raman spectroscopy detection perf...Au-Ag alloy nanostars based flexible paper surface enhanced Raman spectroscopy sensors were fabricated through simple nanostar coating on regular office paper,and the surface enhanced Raman spectroscopy detection performances were investigated using crystal violet dye analyte.Au-Ag nanostars with sharp tips were synthesized via metal ions reduction method.Transmission electron microscope images,X-Ray diffraction pattern and energy dispersive spectroscopy elemental mapping confirmed the nanostar geometry and Au/Ag components of the nanostructure.UV-Vis-NIR absorption spectrum shows wide local surface plasmon resonance induced optical extinction.In addition,finite-difference time-domain simulation shows much stronger electromagnetic field from nanostars than from sphere nanoparticle.The effect of coating layer on Raman signal intensities was discussed,and optimized 5-layer coating with best Raman signal was obtained.The Au-Ag nanostatrs homogeneously distribute on paper fiber surface.The detection limit is 10-10 M,and the relationship between analyte concentrations and Raman signal intensities shows well linear,for potential quantitative analysis.The calculated enhancement factor is 4.795×10^(6).The flexible paper surface enhanced Raman spectroscopy sensors could be applied for trace chemical and biology molecule detection.展开更多
Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.U...Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:Li+<Na^(+)<K^(+)<Ca^(2+)<Sr^(2+).The structure of interfacial water was optimized by adjusting the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.展开更多
The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testi...The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.展开更多
Due to its ubiquitous occurrence in igneous,metamorphic,and sedimentary rocks and its wide application in geochronology and geochemistry,zircon has become the most widely used accessory mineral in the geological commu...Due to its ubiquitous occurrence in igneous,metamorphic,and sedimentary rocks and its wide application in geochronology and geochemistry,zircon has become the most widely used accessory mineral in the geological community.Nevertheless,the decay of U and Th causes radiation damage to the zircon structure,resulting in various degrees of metamictization,which can affect the accuracy of U–Pb dates and Hf and O isotope results.If the degree of zircon radiation damage can be quantified,the influence on geochemical analyses can be evaluated,and the results can be corrected more precisely.In this paper,synthetic and natural zircon crystals with different crystallization ages were selected for Raman spectroscopy analysis,cathodoluminescence imaging,and determination of the U and Th concentrations.The results show that Raman FWHM(full width at half bandmaximum)and Raman shift correlate with alpha dose(Da)ofzirconsfollowingtheseequations,FWHM=44.36(±2.32)×[1-exp(-2.74×Da)]-+1.7(±0.19),Raman Shift=-6.53×Da+1007.69.Analysis of synthetic zircon crystals shows that doped REEs(rare earth elements and P)can also lead to an increase in the FWHM.However,this effect can be ignored for natural zircon samples with REE contents at a normal level of hundreds to a few thousand ppm.The FWHM and Raman shift can be used as proxies to measure the degree of zircon radiation damage.Using the updated equations to calculate the latest age when zircon began to accumulate radiation damage,a more accurate and more meaningful“radiation damage age”can be obtained.展开更多
BACKGROUND Cancer detection is a global research focus,and novel,rapid,and label-free techniques are being developed for routine clinical practice.This has led to the development of new tools and techniques from the b...BACKGROUND Cancer detection is a global research focus,and novel,rapid,and label-free techniques are being developed for routine clinical practice.This has led to the development of new tools and techniques from the bench side to routine clinical practice.In this study,we present a method that uses Raman spectroscopy(RS)to detect cancer in unstained formalin-fixed,resected specimens of the esophagus and stomach.Our method can record a clear Raman-scattered light spectrum in these specimens,confirming that the Raman-scattered light spectrum changes because of the histological differences in the mucosal tissue.AIM To evaluate the use of Raman-scattered light spectrum for detecting endoscopically resected specimens of esophageal squamous cell carcinoma(SCC)and gastric adenocarcinoma(AC).METHODS We created a Raman device that is suitable for observing living tissues,and attempted to acquire Raman-scattered light spectra in endoscopically resected specimens of six esophageal tissues and 12 gastric tissues.We evaluated formalin-fixed tissues using this technique and captured shifts at multiple locations based on feasibility,ranging from six to 19 locations 200 microns apart in the vertical and horizontal directions.Furthermore,a correlation between the obtained Raman scattered light spectra and histopathological diagnosis was performed.RESULTS We successfully obtained Raman scattered light spectra from all six esophageal and 12 gastric specimens.After data capture,the tissue specimens were sent for histopathological analysis for further processing because RS is a label-free methodology that does not cause tissue destruction or alterations.Based on data analysis of molecular-level substrates,we established cut-off values for the diagnosis of esophageal SCC and gastric AC.By analyzing specific Raman shifts,we developed an algorithm to identify the range of esophageal SCC and gastric AC with an accuracy close to that of histopathological diagnoses.CONCLUSION Our technique provides qualitative information for real-time morphological diagnosis.However,further in vivo evaluations require an excitation light source with low human toxicity and large amounts of data for validation.展开更多
The skin is the largest organ in humans.It comprises about 16%of our body.Many diseases originate from the skin,including acne vulgaris,skin cancer,fungal skin disease,etc.As a common skin cancer in China,melanoma alo...The skin is the largest organ in humans.It comprises about 16%of our body.Many diseases originate from the skin,including acne vulgaris,skin cancer,fungal skin disease,etc.As a common skin cancer in China,melanoma alone grows at year rate of nearly 4%.Therefore,it is crucial to develop an objective,reliable,accurate,non-invasive,and easy-to-use diagnostic method for skin diseases to support clinical decision-making.Raman spectroscopy is a highly specic imaging technique,which is sensitive,even to the single-cell level in skin diagnosis.Raman spectroscopy provides a pattern of signals with narrow bandwidths,making it a common and essential tool for researching individual characteristics of skin cells.Raman spectroscopy already has a number of clinical applications,including in thyroid,cervical and colorectal cancer.This review will introduce the advantages and recent developments in Raman spectroscopy,before focusing on the advances in skin diagnosis,including the advantages,methods,results,analysis,and notications.Finally,we discuss the current limitations and future progress of Raman spectroscopy in the context of skin diagnosis.展开更多
Electronic properties of two-dimensional(2D) materials can be strongly modulated by localized strain. The typical spatial resolution of conventional Kelvin probe force microscopy(KPFM) is usually limited in a few hund...Electronic properties of two-dimensional(2D) materials can be strongly modulated by localized strain. The typical spatial resolution of conventional Kelvin probe force microscopy(KPFM) is usually limited in a few hundreds of nanometers, and it is difficult to characterize localized electronic properties of 2D materials at nanoscales. Herein, tip-enhanced Raman spectroscopy(TERS) is proposed to combine with KPFM to break this restriction. TERS scan is conducted on ReS2bubbles deposited on a rough Au thin film to obtain strain distribution by using the Raman peak shift. The localized contact potential difference(CPD) is inversely calculated with a higher spatial resolution by using strain measured by TERS and CPD-strain working curve obtained using conventional KPFM and atomic force microscopy. This method enhances the spatial resolution of CPD measurements and can be potentially used to characterize localized electronic properties of 2D materials.展开更多
Bronze phase titanium dioxide(TiO_(2)(B))could be a promising high-power anode for lithium ion battery.However,TiO_(2)(B)is a metastable material,so the as-synthesized samples are inevitably accompanied by the existen...Bronze phase titanium dioxide(TiO_(2)(B))could be a promising high-power anode for lithium ion battery.However,TiO_(2)(B)is a metastable material,so the as-synthesized samples are inevitably accompanied by the existence of anatase phases.It has been found that the TiO_(2)(B)'s purity is positively correlated with its electrochemical performance.Herein,we have established an accurate quantification of the TiO_(2)(B)/anatase ratio,by figuring out the function between the purity of TiO_(2)(B)phase in the high purity range and its Raman spectra features in combination of the calibration by the synchrotron radiation X-ray diffraction(XRD).Compared with the time-consuming electrochemical method,the rapid,sensitive and non-destructive features of Raman spectroscopy have made it a promising candidate for determining the purity of TiO_(2)(B).Further,the correlations developed in this work should be instructive in synthesizing pure TiO_(2)(B)and furthermore optimizing its electrochemical charge storage properties.展开更多
As one type of spatially offset Raman spectroscopy(SORS), inverse SORS is particularly suited to in vivo biomedical measurements due to its ring-shaped illumination scheme. To explain inhomogeneous Raman scattering du...As one type of spatially offset Raman spectroscopy(SORS), inverse SORS is particularly suited to in vivo biomedical measurements due to its ring-shaped illumination scheme. To explain inhomogeneous Raman scattering during in vivo inverse SORS measurements, the light–tissue interactions when excitation and regenerated Raman photons propagate in skin tissue were studied using Monte Carlo simulation. An eight-layered skin model was first built based on the latest transmission parameters. Then, an open-source platform, Monte Carlo e Xtreme(MCX), was adapted to study the distribution of 785 nm excitation photons inside the model with an inverse spatially shifted annular beam. The excitation photons were converted to emission photons by an inverse distribution method based on excitation flux with spatial offsets Δs of 1 mm, 2 mm, 3 mm and 5 mm. The intrinsic Raman spectra from separated skin layers were measured by continuous linear scanning to improve the simulation accuracy. The obtained results explain why the spectral detection depth gradually increases with increasing spatial offset, and address how the intrinsic Raman spectrum from deep skin layers is distorted by the reabsorption and scattering of the superficial tissue constituents. Meanwhile, it is demonstrated that the spectral contribution from subcutaneous fat will be improved when the offset increases to 5 mm, and the highest detection efficiency for dermal layer spectral detection could be achieved when Δs = 2 mm. Reasonably good matching between the calculated spectrum and the measured in vivo inverse SORS was achieved, thus demonstrating great utility of our modeling method and an approach to help understand the clinical measurements.展开更多
Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with...Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).展开更多
Raman spectroscopy has found extensive use in monitoring and controlling cell culture processes.In this context,the prediction accuracy of Raman-based models is of paramount importance.However,models established with ...Raman spectroscopy has found extensive use in monitoring and controlling cell culture processes.In this context,the prediction accuracy of Raman-based models is of paramount importance.However,models established with data from manually fed-batch cultures often exhibit poor performance in Raman-controlled cultures.Thus,there is a need for effective methods to rectify these models.The objective of this paper is to investigate the efficacy of Kalman filter(KF)algorithm in correcting Raman-based models during cell culture.Initially,partial least squares(PLS)models for different components were constructed using data from manually fed-batch cultures,and the predictive performance of these models was compared.Subsequently,various correction methods including the PLS-KF-KF method proposed in this study were employed to refine the PLS models.Finally,a case study involving the auto-control of glucose concentration demonstrated the application of optimal model correction method.The results indicated that the original PLS models exhibited differential performance between manually fed-batch cultures and Raman-controlled cultures.For glucose,the root mean square error of prediction(RMSEP)of manually fed-batch culture and Raman-controlled culture was 0.23 and 0.40 g·L^(-1).With the implementation of model correction methods,there was a significant improvement in model performance within Raman-controlled cultures.The RMSEP for glucose from updating-PLS,KF-PLS,and PLS-KF-KF was 0.38,0.36 and 0.17 g·L^(-1),respectively.Notably,the proposed PLS-KF-KF model correction method was found to be more effective and stable,playing a vital role in the automated nutrient feeding of cell cultures.展开更多
The application of vibrational spectroscopy in the pharmaceutical industry is widely investigated, from the quality assurance of the product during the production process control to the final products’ quality contro...The application of vibrational spectroscopy in the pharmaceutical industry is widely investigated, from the quality assurance of the product during the production process control to the final products’ quality control and the authentication of products on the markets. This study focuses on non-contact and noninvasive detection and identification of pain-relievers at 1-5 meters standoff distances. The specimens analyzed include standard laboratory-grade active ingredients and commercially available pain relievers in powder, solid and liquid forms. All the remote measurements captured revealed the Raman signatures of the specimens, with varying peak intensities. To correlate the band intensities captured with the standoff distances between the laser source and the specimens, the intensity ratios of the two prominent peaks of the laboratory grade reference active ingredient (1607 and 1319 cm<sup>-1</sup>) normalized with 1319 cm<sup>-1</sup> are used. The results of the study suggest the viability of standoff Raman spectroscopy for routine monitoring and identification of pharma-ceuticals, including counterfeit pain relievers.展开更多
Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-s...Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe_(3)O_(4)@Au MNPs(as the recognize probe for histamine)and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile(4-MBN)(Ag@4-MBN@Ag-c-DNA)as the SERS signal probe for the indirect detection of histamine.Under an applied magnetic field in the absence of histamine,the assembly gave an intense Raman signal at“Raman biological-silent”region due to 4-MBN.In the presence of histamine,the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe_(3)O_(4)@Au MNPs,thus decreasing the SERS signal.Under optimal conditions,an ultra-low limit of detection of 0.65×10^(-3)ng/mL and a linear range 10^(-2)-10^5 ng/mL on the SERS aptasensor were obtained.The histamine content in four food samples were analyzed using the SERS aptasensor,with the results consistent with those determined by high performance liquid chromatography.The present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices.展开更多
As a crop quality sensor,Raman spectroscopy has been consistently proposed as one of the most promising and non-destructive methods for qualitative and quantitative analysis of plant substances,because it can measure ...As a crop quality sensor,Raman spectroscopy has been consistently proposed as one of the most promising and non-destructive methods for qualitative and quantitative analysis of plant substances,because it can measure molecular structures in a short time without requiring pretreatment along with simple usage.The sensitivity of the Raman spectrum to target chemicals depends largely on the wavelength,intensity of the laser power,and exposure time.Especially for plant samples,it is very likely that the peak of the target material is covered by strong fluorescence effects.Therefore,methods using lasers with low energy causing less fluorescence,such as 785 nm or near-infrared,are vigorously discussed.Furthermore,advanced techniques for obtaining more sensitive and clear spectra,like surface-enhanced Raman spectroscopy,time-gated Raman spectroscopy or combination with thin-layer chromatography,are being investigated.Numerous interpretations of plant quality can be represented not only by the measurement conditions but also by the spectral analysis methods.Up to date,there have been attempted to optimize and generalize analysis methods.This review summarizes the state of the art of micro-Raman spectroscopy in crop quality assessment focusing on secondary metabolites,from in vitro to in vivo and even in situ,and suggests future research to achieve universal application.展开更多
Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson...Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.展开更多
基金the immense support provided by the National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIT)(RS-2023–00210114)the National R&D Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(2021M3D1A2051636)。
文摘Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic insights.In this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the HER.In addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during HER.These spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.
基金the support from Scientific Research Project of Wuhan Polytechnic University(532100308).
文摘Staling is an important issue that Chinese steamed bread(CSB)may encounter during storage,which significantly affects their taste,flavor,and nutritional value.The monitoring technology for rapid aging is particularly important to effectively control the aging process of CSB,reduce quality deterioration,and promote the industrial production of CSB.Raman spectroscopy has been widely used in the study of food structure and properties due to its non-destructive and high-sensitivity characteristics,particularly demonstrating unique advantages in the analysis of starch structure.This study explored the possibility of analyzing the staling of CSB using Raman spectroscopy based on hardness and moisture content.Analysis of the correlation between the hardness of CSB and the full width at half maximum(FWHM)at 480 cm^(−1)during storage was conducted,and a significant positive correlation between them was found,with R^(2)above 0.8.Besides,nine characteristic peaks of CSB samples related to starch were selected for analysis.As the moisture content of CSB decreased,the peak intensities and areas of showed an upward trend during storage,with the best correlation coefficient above 0.8 revealed by linear regression analysis.Therefore,Raman spectra could be used as a potential method for the fast prediction of CSB staling.
基金Funded by the Project of Sanya Yazhou Bay Science and Technology City(No.SCKJ-JYRC-2022-44)the Fundamental Research Funds for the Central Universities(WUT:2023Ⅲ007XXH)。
文摘Au-Ag alloy nanostars based flexible paper surface enhanced Raman spectroscopy sensors were fabricated through simple nanostar coating on regular office paper,and the surface enhanced Raman spectroscopy detection performances were investigated using crystal violet dye analyte.Au-Ag nanostars with sharp tips were synthesized via metal ions reduction method.Transmission electron microscope images,X-Ray diffraction pattern and energy dispersive spectroscopy elemental mapping confirmed the nanostar geometry and Au/Ag components of the nanostructure.UV-Vis-NIR absorption spectrum shows wide local surface plasmon resonance induced optical extinction.In addition,finite-difference time-domain simulation shows much stronger electromagnetic field from nanostars than from sphere nanoparticle.The effect of coating layer on Raman signal intensities was discussed,and optimized 5-layer coating with best Raman signal was obtained.The Au-Ag nanostatrs homogeneously distribute on paper fiber surface.The detection limit is 10-10 M,and the relationship between analyte concentrations and Raman signal intensities shows well linear,for potential quantitative analysis.The calculated enhancement factor is 4.795×10^(6).The flexible paper surface enhanced Raman spectroscopy sensors could be applied for trace chemical and biology molecule detection.
基金the National Key Research and Development Program of China(2019YFA0705400)the National Natural Science Foundation of China(T2293692,21925404,22021001,21991151,and 22002036)+1 种基金the Natural Science Foundation of Fujian Province of China(2021J06001)the National Natural Science Foundation of Henan province(232300421081).
文摘Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:Li+<Na^(+)<K^(+)<Ca^(2+)<Sr^(2+).The structure of interfacial water was optimized by adjusting the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.
基金funded by the Defence Science Technology Group(DSTG)。
文摘The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.
基金supported by funds from the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB 41000000)the National Natural Science Foundation of China(41973002,41772187)+1 种基金the Fundamental Research Funds for the Central UniversitiesNatural Sciences and Engineering Research Council of Canada(NSERC)Discovery Grant to J.M Hanchar(RGPIN/004649-2015)。
文摘Due to its ubiquitous occurrence in igneous,metamorphic,and sedimentary rocks and its wide application in geochronology and geochemistry,zircon has become the most widely used accessory mineral in the geological community.Nevertheless,the decay of U and Th causes radiation damage to the zircon structure,resulting in various degrees of metamictization,which can affect the accuracy of U–Pb dates and Hf and O isotope results.If the degree of zircon radiation damage can be quantified,the influence on geochemical analyses can be evaluated,and the results can be corrected more precisely.In this paper,synthetic and natural zircon crystals with different crystallization ages were selected for Raman spectroscopy analysis,cathodoluminescence imaging,and determination of the U and Th concentrations.The results show that Raman FWHM(full width at half bandmaximum)and Raman shift correlate with alpha dose(Da)ofzirconsfollowingtheseequations,FWHM=44.36(±2.32)×[1-exp(-2.74×Da)]-+1.7(±0.19),Raman Shift=-6.53×Da+1007.69.Analysis of synthetic zircon crystals shows that doped REEs(rare earth elements and P)can also lead to an increase in the FWHM.However,this effect can be ignored for natural zircon samples with REE contents at a normal level of hundreds to a few thousand ppm.The FWHM and Raman shift can be used as proxies to measure the degree of zircon radiation damage.Using the updated equations to calculate the latest age when zircon began to accumulate radiation damage,a more accurate and more meaningful“radiation damage age”can be obtained.
基金Supported by MEXT KAKENHI,JP17K09022 and JP20K07643.
文摘BACKGROUND Cancer detection is a global research focus,and novel,rapid,and label-free techniques are being developed for routine clinical practice.This has led to the development of new tools and techniques from the bench side to routine clinical practice.In this study,we present a method that uses Raman spectroscopy(RS)to detect cancer in unstained formalin-fixed,resected specimens of the esophagus and stomach.Our method can record a clear Raman-scattered light spectrum in these specimens,confirming that the Raman-scattered light spectrum changes because of the histological differences in the mucosal tissue.AIM To evaluate the use of Raman-scattered light spectrum for detecting endoscopically resected specimens of esophageal squamous cell carcinoma(SCC)and gastric adenocarcinoma(AC).METHODS We created a Raman device that is suitable for observing living tissues,and attempted to acquire Raman-scattered light spectra in endoscopically resected specimens of six esophageal tissues and 12 gastric tissues.We evaluated formalin-fixed tissues using this technique and captured shifts at multiple locations based on feasibility,ranging from six to 19 locations 200 microns apart in the vertical and horizontal directions.Furthermore,a correlation between the obtained Raman scattered light spectra and histopathological diagnosis was performed.RESULTS We successfully obtained Raman scattered light spectra from all six esophageal and 12 gastric specimens.After data capture,the tissue specimens were sent for histopathological analysis for further processing because RS is a label-free methodology that does not cause tissue destruction or alterations.Based on data analysis of molecular-level substrates,we established cut-off values for the diagnosis of esophageal SCC and gastric AC.By analyzing specific Raman shifts,we developed an algorithm to identify the range of esophageal SCC and gastric AC with an accuracy close to that of histopathological diagnoses.CONCLUSION Our technique provides qualitative information for real-time morphological diagnosis.However,further in vivo evaluations require an excitation light source with low human toxicity and large amounts of data for validation.
基金support received from the Medicine and Engineering Cross Research Foundation of Shanghai Jiao Tong University(Project No.YG2022QN047)as well as the National Nature Science Foundation of China(Grant No.62027824)the National Key Research and Development Program of China(2019YFC1604604).
文摘The skin is the largest organ in humans.It comprises about 16%of our body.Many diseases originate from the skin,including acne vulgaris,skin cancer,fungal skin disease,etc.As a common skin cancer in China,melanoma alone grows at year rate of nearly 4%.Therefore,it is crucial to develop an objective,reliable,accurate,non-invasive,and easy-to-use diagnostic method for skin diseases to support clinical decision-making.Raman spectroscopy is a highly specic imaging technique,which is sensitive,even to the single-cell level in skin diagnosis.Raman spectroscopy provides a pattern of signals with narrow bandwidths,making it a common and essential tool for researching individual characteristics of skin cells.Raman spectroscopy already has a number of clinical applications,including in thyroid,cervical and colorectal cancer.This review will introduce the advantages and recent developments in Raman spectroscopy,before focusing on the advances in skin diagnosis,including the advantages,methods,results,analysis,and notications.Finally,we discuss the current limitations and future progress of Raman spectroscopy in the context of skin diagnosis.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China (Grant No. LZ22A040003)the National Natural Science Foundation of China (Grant No. 52027809)。
文摘Electronic properties of two-dimensional(2D) materials can be strongly modulated by localized strain. The typical spatial resolution of conventional Kelvin probe force microscopy(KPFM) is usually limited in a few hundreds of nanometers, and it is difficult to characterize localized electronic properties of 2D materials at nanoscales. Herein, tip-enhanced Raman spectroscopy(TERS) is proposed to combine with KPFM to break this restriction. TERS scan is conducted on ReS2bubbles deposited on a rough Au thin film to obtain strain distribution by using the Raman peak shift. The localized contact potential difference(CPD) is inversely calculated with a higher spatial resolution by using strain measured by TERS and CPD-strain working curve obtained using conventional KPFM and atomic force microscopy. This method enhances the spatial resolution of CPD measurements and can be potentially used to characterize localized electronic properties of 2D materials.
基金This work was financially supported by the National Natural Science Foundation of China(22075074)Outstanding Young Scientists Research Funds from Hunan Province(2020JJ2004)+3 种基金Major Science and Technology Program of Hunan Province(2020WK2013)Natural Science Foundation of Hunan Province(2020JJ5035)National Natural Science Foundation of China(Grant No.11704185)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(SKL201802SIC).
文摘Bronze phase titanium dioxide(TiO_(2)(B))could be a promising high-power anode for lithium ion battery.However,TiO_(2)(B)is a metastable material,so the as-synthesized samples are inevitably accompanied by the existence of anatase phases.It has been found that the TiO_(2)(B)'s purity is positively correlated with its electrochemical performance.Herein,we have established an accurate quantification of the TiO_(2)(B)/anatase ratio,by figuring out the function between the purity of TiO_(2)(B)phase in the high purity range and its Raman spectra features in combination of the calibration by the synchrotron radiation X-ray diffraction(XRD).Compared with the time-consuming electrochemical method,the rapid,sensitive and non-destructive features of Raman spectroscopy have made it a promising candidate for determining the purity of TiO_(2)(B).Further,the correlations developed in this work should be instructive in synthesizing pure TiO_(2)(B)and furthermore optimizing its electrochemical charge storage properties.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61911530695)the Key Research and Development Project of Shaanxi Province, China (Grant No. 2023-YBSF-671)。
文摘As one type of spatially offset Raman spectroscopy(SORS), inverse SORS is particularly suited to in vivo biomedical measurements due to its ring-shaped illumination scheme. To explain inhomogeneous Raman scattering during in vivo inverse SORS measurements, the light–tissue interactions when excitation and regenerated Raman photons propagate in skin tissue were studied using Monte Carlo simulation. An eight-layered skin model was first built based on the latest transmission parameters. Then, an open-source platform, Monte Carlo e Xtreme(MCX), was adapted to study the distribution of 785 nm excitation photons inside the model with an inverse spatially shifted annular beam. The excitation photons were converted to emission photons by an inverse distribution method based on excitation flux with spatial offsets Δs of 1 mm, 2 mm, 3 mm and 5 mm. The intrinsic Raman spectra from separated skin layers were measured by continuous linear scanning to improve the simulation accuracy. The obtained results explain why the spectral detection depth gradually increases with increasing spatial offset, and address how the intrinsic Raman spectrum from deep skin layers is distorted by the reabsorption and scattering of the superficial tissue constituents. Meanwhile, it is demonstrated that the spectral contribution from subcutaneous fat will be improved when the offset increases to 5 mm, and the highest detection efficiency for dermal layer spectral detection could be achieved when Δs = 2 mm. Reasonably good matching between the calculated spectrum and the measured in vivo inverse SORS was achieved, thus demonstrating great utility of our modeling method and an approach to help understand the clinical measurements.
基金supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park (Project HZQBKCZYB-2020030)National Key R&D Program of China (Project 2017YFA0204403)+2 种基金the National Natural Science Foundation of China (Project 51590892)the Major Program of Changsha Science and Technology (Project kh2003023)the Innovation and Technology Commission of HKSAR through Hong Kong Branch of National Precious Metals Material Engineering Research Centre,and the City University of Hong Kong (Project 9667207)。
文摘Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).
基金supported by the Key Research and Development Program of Zhejiang Province,China(2023C03116).
文摘Raman spectroscopy has found extensive use in monitoring and controlling cell culture processes.In this context,the prediction accuracy of Raman-based models is of paramount importance.However,models established with data from manually fed-batch cultures often exhibit poor performance in Raman-controlled cultures.Thus,there is a need for effective methods to rectify these models.The objective of this paper is to investigate the efficacy of Kalman filter(KF)algorithm in correcting Raman-based models during cell culture.Initially,partial least squares(PLS)models for different components were constructed using data from manually fed-batch cultures,and the predictive performance of these models was compared.Subsequently,various correction methods including the PLS-KF-KF method proposed in this study were employed to refine the PLS models.Finally,a case study involving the auto-control of glucose concentration demonstrated the application of optimal model correction method.The results indicated that the original PLS models exhibited differential performance between manually fed-batch cultures and Raman-controlled cultures.For glucose,the root mean square error of prediction(RMSEP)of manually fed-batch culture and Raman-controlled culture was 0.23 and 0.40 g·L^(-1).With the implementation of model correction methods,there was a significant improvement in model performance within Raman-controlled cultures.The RMSEP for glucose from updating-PLS,KF-PLS,and PLS-KF-KF was 0.38,0.36 and 0.17 g·L^(-1),respectively.Notably,the proposed PLS-KF-KF model correction method was found to be more effective and stable,playing a vital role in the automated nutrient feeding of cell cultures.
文摘The application of vibrational spectroscopy in the pharmaceutical industry is widely investigated, from the quality assurance of the product during the production process control to the final products’ quality control and the authentication of products on the markets. This study focuses on non-contact and noninvasive detection and identification of pain-relievers at 1-5 meters standoff distances. The specimens analyzed include standard laboratory-grade active ingredients and commercially available pain relievers in powder, solid and liquid forms. All the remote measurements captured revealed the Raman signatures of the specimens, with varying peak intensities. To correlate the band intensities captured with the standoff distances between the laser source and the specimens, the intensity ratios of the two prominent peaks of the laboratory grade reference active ingredient (1607 and 1319 cm<sup>-1</sup>) normalized with 1319 cm<sup>-1</sup> are used. The results of the study suggest the viability of standoff Raman spectroscopy for routine monitoring and identification of pharma-ceuticals, including counterfeit pain relievers.
基金financially supported by the National Natural Science Foundation of China(31972149)funding support from the MacDiarmid Institute for Advanced Materials and Nanotechnologythe Dodd-Walls Centre for Photonic and Quantum Technologies。
文摘Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe_(3)O_(4)@Au MNPs(as the recognize probe for histamine)and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile(4-MBN)(Ag@4-MBN@Ag-c-DNA)as the SERS signal probe for the indirect detection of histamine.Under an applied magnetic field in the absence of histamine,the assembly gave an intense Raman signal at“Raman biological-silent”region due to 4-MBN.In the presence of histamine,the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe_(3)O_(4)@Au MNPs,thus decreasing the SERS signal.Under optimal conditions,an ultra-low limit of detection of 0.65×10^(-3)ng/mL and a linear range 10^(-2)-10^5 ng/mL on the SERS aptasensor were obtained.The histamine content in four food samples were analyzed using the SERS aptasensor,with the results consistent with those determined by high performance liquid chromatography.The present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices.
基金This study was partially supported by the Federal Ministry of Education and Research(BMBF)through the program Agricul-tural Agricul-tural Systems of the Future in the framework of the“National Research Strategy BioEconomy 2030”under grant No.031B0728A“SUSKULT-Development of a Sustainable Cultivation System of Resilient Metropolitan Regions”through the program“Model Region Bioeconomy in the Rhenish mining area”under grant No.031B1137BX“Model region,Phase 1,BioRevierPLUS:InnoLA,TP2-circular PhytoREVIER”.
文摘As a crop quality sensor,Raman spectroscopy has been consistently proposed as one of the most promising and non-destructive methods for qualitative and quantitative analysis of plant substances,because it can measure molecular structures in a short time without requiring pretreatment along with simple usage.The sensitivity of the Raman spectrum to target chemicals depends largely on the wavelength,intensity of the laser power,and exposure time.Especially for plant samples,it is very likely that the peak of the target material is covered by strong fluorescence effects.Therefore,methods using lasers with low energy causing less fluorescence,such as 785 nm or near-infrared,are vigorously discussed.Furthermore,advanced techniques for obtaining more sensitive and clear spectra,like surface-enhanced Raman spectroscopy,time-gated Raman spectroscopy or combination with thin-layer chromatography,are being investigated.Numerous interpretations of plant quality can be represented not only by the measurement conditions but also by the spectral analysis methods.Up to date,there have been attempted to optimize and generalize analysis methods.This review summarizes the state of the art of micro-Raman spectroscopy in crop quality assessment focusing on secondary metabolites,from in vitro to in vivo and even in situ,and suggests future research to achieve universal application.
文摘Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.