5,764 results match your criteria spectra derivative


Development of a soil heavy metal estimation method based on a spectral index: Combining fractional-order derivative pretreatment and the absorption mechanism.

Sci Total Environ 2021 Nov 22:151882. Epub 2021 Nov 22.

The Second Surveying and Mapping Institute of Hebei, Shijiazhuang 050037, China.

Visible and near-infrared (Vis-NIR) reflectance is an effective way to estimate soil heavy metal content. In this study, in order to magnify the spectral information of the soil heavy metals and solve the collinearity and redundancy of hyperspectral datasets, we aimed to explore the potential of the fractional-order derivative (FOD) spectral pretreatment method and the band combination algorithm in soil heavy metal estimation. A total of 120 soil samples were collected in Xuzhou city, Jiangsu province, China, and their heavy metal contents and spectra were measured. Read More

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November 2021

Simultaneous estimation of recently FDA approved co-formulated ophthalmic solution benoxinate and fluorescein: Application to aqueous humor.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Nov 16:120599. Epub 2021 Nov 16.

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Horus University-Egypt, New Damietta, Egypt.

Nine simple, cost-effective, and sensitive spectrophotometric methods were developed to simultaneously assay benoxinate HCl and fluorescein sodium in their co-formulated eye drops without barring common excipients. A direct UV spectrophotometric method (method I) was developed for their FLU assay at 481 nm over the concentration range of 0.6-10. Read More

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November 2021

An innovative spectroscopic approach for qualitative and quantitative evaluation of Mb-CO from myoglobin carbonylation reaction through chemometrics methods.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Nov 11:120602. Epub 2021 Nov 11.

Federal University of Rio de Janeiro (UFRJ), Institute of Microbiology Paulo de Góes, BIOINOVAR - Biocatalysis, Bioproducts and Bioenergy, Rio de Janeiro, Brazil. Electronic address:

In this work, an innovative approach using K-means and multivariate curve resolution-purity based algorithm (MCR-Purity) for the evaluation and quantification of carboxymyoglobin (Mb-CO) formation from Deoxy-Myoglobin (Deoxy-Mb) was presented. Through a multilevel multifactor experimental design, samples with different concentrations of Mb-CO were created. The UV-Vis spectra of these samples were submitted to K-means analysis, finding 3 clusters. Read More

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November 2021

CuMnGeS and CuMnGeS: two polar thiogermanates exhibiting second harmonic generation in the infrared and structures derived from hexagonal diamond.

Dalton Trans 2021 Nov 19. Epub 2021 Nov 19.

Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, USA.

The new, quaternary diamond-like semiconductor (DLS) CuMnGeS was prepared at high-temperature from a stoichiometric reaction of the elements under vacuum. Single crystal X-ray diffraction data were used to solve and refine the structure in the polar space group CuMnGeS features [GeS] units and adopts the CuSiS structure type that can be considered a derivative of the hexagonal diamond structure. The DLS CuMnGeS with the wurtz-stannite structure was similarly prepared at a lower temperature. Read More

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November 2021

New furan derivatives from fungus.

J Asian Nat Prod Res 2021 Nov 18:1-8. Epub 2021 Nov 18.

Natural Products Research Unit, Centre of Excellence for Innovation in Chemistry (PERCH-CIC), Department of Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.

Two new furan derivatives, annulofurans A-B (-), together with six known compounds were isolated from fungus. The structures were determined based on NMR and mass spectrometry data. The absolute configurations of annulofurans A-B were determined by Electronic Circular Dichroism (ECD) experiment and comparisons with the experimental ECD spectra of synthesized stereoisomers. Read More

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November 2021

First-order derivative synchronous spectrofluorimetric determination of two antihypertensive drugs, metolazone and valsartan, in pharmaceutical and biological matrices.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Nov 8:120591. Epub 2021 Nov 8.

Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.

In this study, a facile, rapid, and sensitive spectrofluorimetric method was evolved to analyse two antihypertensive drugs, namely, metolazone (MTZ) and valsartan (VST), in pharmaceutical and biological matrices. Both analytes exhibited intrinsic fluorescence activities which were significantly affected by environmental factors such as pH and solvent systems. However, simultaneous determination of MTZ and VST by conventional spectrofluorometry cannot be achieved simply because of the strong overlap between their fluorescence spectra. Read More

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November 2021

In Situ Determination of Cannabidiol in Hemp Oil by Near-Infrared Spectroscopy.

J Nat Prod 2021 Nov 16;84(11):2851-2857. Epub 2021 Nov 16.

G2 Analytical, PO Box 851, Wingate, North Carolina 28174, United States.

Cannabidiol (CBD, ) is an active component of hemp oil and many other products that offers diverse health benefits. Near-infrared spectroscopy (NIRS) coupled with chemometrics was utilized to quantify the CBD () concentration in the hemp oil through the containing glass vial. NIRS provided a fast and cost-effective tool to measure chemical profiles for the hemp oil samples with various concentrations of CBD () and its acid precursor, i. Read More

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November 2021

Remotely sensed estimation of total iron content in soil with harmonic analysis and BP neural network.

Plant Methods 2021 Nov 12;17(1):116. Epub 2021 Nov 12.

School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, 430079, China.

Background: The estimation of total iron content at the regional scale is of much significance as iron deficiency has become a routine problem for many crops.

Methods: In this study, a novel method for estimating total iron content in soil (TICS) was proposed using harmonic analysis (HA) and back propagation (BP) neural network model. Several data preprocessing methods of first derivative (FD), wavelet packet transform (WPT), and HA were conducted to improve the correlation between the soil spectra and TICS. Read More

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November 2021

Core-Level Spectroscopy of 2-Thiouracil at the Sulfur L- and L-Edges Utilizing a SASE Free-Electron Laser.

Molecules 2021 Oct 26;26(21). Epub 2021 Oct 26.

Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam, Germany.

In this paper, we report X-ray absorption and core-level electron spectra of the nucleobase derivative 2-thiouracil at the sulfur L- and L-edges. We used soft X-rays from the free-electron laser FLASH2 for the excitation of isolated molecules and dispersed the outgoing electrons with a magnetic bottle spectrometer. We identified photoelectrons from the 2p core orbital, accompanied by an electron correlation satellite, as well as resonant and non-resonant Coster-Kronig and Auger-Meitner emission at the L- and L-edges, respectively. Read More

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October 2021

A novel [1,2,4]triazolo[1,5-a]pyrimidine derivative as a fluorescence probe for specific detection of Fe ions and application in cell imaging.

Anal Chim Acta 2021 Dec 14;1187:339168. Epub 2021 Oct 14.

Qingdao University, Qingdao, 266042, PR China.

The detection of metal ions is of particular importance for monitoring environmental pollution and life metabolic activities. However, it is still a challenge to achieve Fe detection with specific sensitivity and rapid response, especially in the presence of chelating agents for Fe ions. Herein, a novel fluorescence probe for Fe, i. Read More

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December 2021

Switching Pathways of Triplet State Formation by Twisted Intramolecular Charge Transfer.

J Phys Chem B 2021 Nov 9;125(45):12518-12527. Epub 2021 Nov 9.

State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, Dalian University of Technology, 116024, Dalian, China.

With the aim of constructing efficient photoelectric organic materials, a pyrido[3,2-]quinoline derivative named LA17b has been synthesized, and its photodynamic relaxation processes in solvents and films were studied by time-resolved fluorescence and femtosecond transient absorption techniques. The steady-state fluorescence spectra show pronounced red-shift with the increase of the solvent polarity as well as in binary solvent hexane/ethanol by increasing ethanol concentration. However, the strong red-shift does not lead to quenching of the fluorescence. Read More

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November 2021

Enhanced visible/near-infrared spectroscopic data for prediction of quality attributes in Cucurbitaceae commodities.

Data Brief 2021 Dec 8;39:107458. Epub 2021 Oct 8.

Department of Agricultural Engineering, Faculty of Agriculture, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia.

Spectra data of 300 samples from 6 Cucurbitaceae commodities, including zucchini, bitter gourd, ridge gourd, melon, chayote, and cucumber, were recorded using a handheld visible/near-infrared (Vis/NIR) instrument. Vis/NIR data were obtained in the form of absorbance spectra data at a wavelength of 381-1065 nm. The spectral data has the potential to be reused to predict quality attributes in the form of soluble solids and water content on several Cucurbitaceae commodities. Read More

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December 2021

WEAK SINDY FOR PARTIAL DIFFERENTIAL EQUATIONS.

J Comput Phys 2021 Oct 23;443. Epub 2021 Jun 23.

Department of Applied Mathematics, University of Colorado Boulder, 11 Engineering Dr., Boulder, CO 80309, USA.

Sparse Identification of Nonlinear Dynamics (SINDy) is a method of system discovery that has been shown to successfully recover governing dynamical systems from data [6, 39]. Recently, several groups have independently discovered that the weak formulation provides orders of magnitude better robustness to noise. Here we extend our Weak SINDy (WSINDy) framework introduced in [28] to the setting of partial differential equations (PDEs). Read More

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October 2021

Smart UV-spectrophotometric platforms for rapid green analysis of miconazole nitrate and nystatin in their combined suppositories and dissolution testing.

Drug Dev Ind Pharm 2021 Nov 15:1-12. Epub 2021 Nov 15.

Analytical Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.

Miconazole nitrate (MIC) and nystatin (NYS) combination has proven its effectiveness as a prodigious therapy to cure women's common infections; vaginal candidiasis and vaginal mycosis. Herein, six smart UV-spectrophotometric platforms depending on minimal mathematical manipulation steps were first introduced for the simultaneous green analysis of MIC and NYS in their pure forms and commercial vaginal suppositories without any preliminary separation steps. These platforms included dual-wavelength, ratio difference, mean centering of ratio spectra, first derivative ratio, ratio subtraction, and absorption correction methods. Read More

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November 2021

Rapid quality evaluation of Plantaginis Semen by near infrared spectroscopy combined with chemometrics.

J Pharm Biomed Anal 2022 Jan 22;207:114435. Epub 2021 Oct 22.

School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, PR China; Key Laboratory of Digitalization Quality Evaluation of Chinese Materia Medica of SATCM, Guangzhou 510006, PR China; Research Center for Quality Engineering & Technology of Chinese Materia Medica in Guangdong Universities, Guangzhou 510006, PR China; Research Center for Quality Engineering & Technology of Chinese Materia Medica of Guangdong Province, Guangzhou 510006, PR China. Electronic address:

Objective: To establish a rapid and comprehensive method for the quality evaluation of Plantaginis Semen (PS) by using near-infrared spectroscopy combined with chemometrics to determine the content of geniposidic acid (GEA), verbascoside (VE), isoverbascoside (IVE) and total flavonoids (TF) in PS, as well as the antioxidant activity (AOA).

Methods: The content of GEA, VE and IVE in PS were determined by HPLC, the content of TF in PS was determined by UV-Vis spectrophotometry, and the AOA of PS was characterized by the DPPH, ABTS and FRAP, respectively. Then, the measured values of each item were used as reference values and were correlated with the near infrared spectra of PS. Read More

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January 2022

Evaluation of Optimized Preprocessing and Modeling Algorithms for Prediction of Soil Properties Using VIS-NIR Spectroscopy.

Sensors (Basel) 2021 Oct 11;21(20). Epub 2021 Oct 11.

School of Environmental Sciences, University of Guelph, Guelph, ON N1 G2W1, Canada.

The absorbance spectra for air-dried and ground soil samples from Ontario, Canada were collected in the visible and near-infrared (VIS-NIR) region from 343 to 2200 nm. The study examined thirteen combination of six preprocessing (1st derivative, 2nd derivative, Savitzky-Golay, Gap, SNV and Detrend) method included in 'prospectr' R package along with four modeling approaches: partial least square regression (PLSR), cubist, random forest (RF), and extreme learning machine (ELM) for prediction of the soil organic matter (SOM). The 1st derivative + gap, 2nd derivative + gap and standard normal variance (SNV) were the best preprocessing algorithms. Read More

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October 2021

Structural and Spectral Properties of a Nonclassical C Isomer with Its Hydrogenated Derivative CH in Theory.

ACS Omega 2021 Oct 5;6(41):27101-27111. Epub 2021 Oct 5.

College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, People's Republic of China.

X-ray photoelectron and near-edge X-ray absorption fine structure (NEXAFS) spectra, as well as the ground-state electronic/geometrical structures of a newly discovered nonclassical isomer -C(NC), and two classical fullerene isomers -C and -C with their hydrogenated derivatives [ -CH(NC), -CH, and -CH] have been calculated at the density functional theory (DFT) level. Significant differences were observed in the electronic structures and simulated X-ray spectra after hydrogenation. Simultaneously, both X-ray photoelectron and NEXAFS spectra reflected conspicuous isomer dependence, indicating that the "fingerprints" in the X-ray spectra can offer an effective method for identifying the above-mentioned fullerene isomers. Read More

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October 2021

Vanillin chitosan miscible hydrogel blends and their prospects for 3D printing biomedical applications.

Int J Biol Macromol 2021 Dec 20;192:1266-1275. Epub 2021 Oct 20.

Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece. Electronic address:

In the present study, chitosan (CS) reacted with vanillin through a Schiff base reaction forming the vanillin-CS (VACS) derivative. FTIR and H NMR spectra confirmed the derivatization of CS, the enhanced swelling behavior was long-established while XRD measurement stated the semicrystalline nature of the VACS derivative. In a further step, blends between CS and VACS were prepared in ratios CS/VACS 90/10 up to 10/90 w/w and the formation of hydrogen bonds was noticed through FTIR and XRD measurements. Read More

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December 2021

Development of Ecofriendly Derivative Spectrophotometric Methods for the Simultaneous Quantitative Analysis of Remogliflozin and Vildagliptin from Formulation.

Molecules 2021 Oct 12;26(20). Epub 2021 Oct 12.

Department of Nursing, College of Applied Medical Sciences, King Faisal University, Al Ahsa 31982, Saudi Arabia.

Three rapid, accurate, and ecofriendly processed spectrophotometric methods were validated for the concurrent quantification of remogliflozin (RGE) and vildagliptin (VGN) from formulations using water as dilution solvent. The three methods developed were based on the calculation of the peak height of the first derivative absorption spectra at zero-crossing points, the peak amplitude difference at selected wavelengths of the peak and valley of the ratio spectra, and the peak height of the ratio first derivative spectra. All three methods were validated adapting the ICH regulations. Read More

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October 2021

Chiroptical Switching and Quantitative Chirality Sensing with (Pseudo)halogenated Quinones.

Angew Chem Int Ed Engl 2021 Oct 22. Epub 2021 Oct 22.

Department of Chemistry, Georgetown University, Washington, DC, 20057, USA.

(Pseudo)halogenated quinones react smoothly with chiral amines, amino alcohols, and amino acids toward push-pull conjugates with optical sensing and switching applications. The chiroptically active conjugates serve as redox switches between two reversibly interconverting states with remarkably different UV and CD signatures. Addition of sodium borohydride generates a hydroquinone derivative that is quantitatively re-oxidized to the original quinone upon exposure to air. Read More

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October 2021

Development of total suspended matter prediction in waters using fractional-order derivative spectra.

J Environ Manage 2021 Oct 19;302(Pt A):113958. Epub 2021 Oct 19.

Northeast Institute of Geography and Agroecology, CAS, Changchun, 130102, China. Electronic address:

More and more hyper-spectral satellites will be used to estimate total suspended matter (TSM) in waters instead of multi-spectral satellites, such as China's Gaofen-5 and Zhuhai-1. Although they have not been widely used because of the consistency of sampling and image time. Hence, the study based on measured hyper-spectroscopy is important for applying to hyper-spectral satellites. Read More

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October 2021

Discrimination of Pharmaceutical Tablets Based on the Analysis of Solid-State Structures of Ingredients Using Terahertz Transmission Spectroscopy with the Injection-Seeded Parametric Generation Technique.

ACS Omega 2021 Oct 1;6(40):26707-26714. Epub 2021 Oct 1.

Hitachi High-Tech Corporation, Shinko-cho, Hitachinaka 312-8504, Japan.

A frequency-domain terahertz (THz) spectrometer that uses a tunable source, called an injection-seeded THz parametric generator, was applied to the analysis of solid-state structures of ingredients in pharmaceutical tablets, and its performance on discriminating pharmaceutical products was evaluated. The spectrometer has a dynamic range of 70 dB at 2 THz and is suitable for analyzing materials such as pharmaceutical ingredients that often have characteristic absorption peaks between 0.5 and 2. Read More

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October 2021

Diagnosis of Lung Cancer by ATR-FTIR Spectroscopy and Chemometrics.

Front Oncol 2021 30;11:753791. Epub 2021 Sep 30.

School of Physics and Electronic Information, Yunnan Normal University, Kunming, China.

Lung cancer is the leading cause of cancer-related death in the world. Early diagnosis has great significance for the survival of patients with lung cancer. In this paper, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy combined with chemometrics was used to study the serum samples from patients with lung cancer and healthy people. Read More

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September 2021

Second-derivative synchronous fluorimetry and time-programmed HPLC-fluorescence detection for simultaneous estimation of flibanserin and sitagliptin phosphate in synthetic mixtures and human plasma samples.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 Nov 1;1184:122955. Epub 2021 Oct 1.

Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.

Diabetes Mellitus is directly related to female anaphrodesia. Female Viagra or Flibanserin (FLB), U.S. Read More

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November 2021

Inter-enantiomer conversion dynamics and Johari-Goldstein relaxation of benzophenones.

Sci Rep 2021 Oct 12;11(1):20248. Epub 2021 Oct 12.

Grup de Caracterizació de Materials, Departament de Física, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, Av. Eduard Maristany 10-14, 08019, Barcelona, Catalonia, Spain.

We employ temperature- and pressure-dependent dielectric spectroscopy, as well as differential scanning calorimetry, to characterize benzophenone and the singly-substituted ortho-bromobenzophenone derivative in the liquid and glass states, and analyze the results in terms of the molecular conformations reported for these molecules. Despite the significantly higher mass of the brominated derivative, its dynamic and calorimetric glass transition temperatures are only ten degrees higher than those of benzophenone. The kinetic fragility index of the halogenated molecule is lower than that of the parent compound, and is found to decrease with increasing pressure. Read More

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October 2021

Molecular Weight-Dependent Physical and Photovoltaic Properties of Poly(3-alkylthiophene)s with Butyl, Hexyl, and Octyl Side-Chains.

Polymers (Basel) 2021 Oct 7;13(19). Epub 2021 Oct 7.

Department of Chemistry, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea.

A series of poly-3-alkylthiophenes (P3ATs) with butyl (P3BT), hexyl (P3HT), and octyl (P3OT) side-chains and well-defined molecular weights (MWs) were synthesized using Grignard metathesis polymerization. The MWs of P3HTs and P3OTs obtained via gel permeation chromatography agreed well with the calculated MWs ranging from approximately 10 to 70 kDa. Differential scanning calorimetry results showed that the crystalline melting temperature increased with increasing MWs and decreasing alkyl side-chain length, whereas the crystallinity of the P3ATs increased with the growth of MWs. Read More

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October 2021

Earth friendly spectrophotometric methods based on different manipulation approaches for simultaneous determination of aspirin and omeprazole in binary mixture and pharmaceutical dosage form: Comparative statistical study.

Spectrochim Acta A Mol Biomol Spectrosc 2022 Feb 27;266:120436. Epub 2021 Sep 27.

Pharmaceutical Chemistry Department, Faculty of Pharmacy, Egyptian Russian University, Badr 11829, Egypt. Electronic address:

Aspirin and omeprazole combining has proven their effectiveness clinically in the treatment and prevention of cardiovascular diseases in patient with gastric diseases and gastric ulcers. Simultaneous determination of omeprazole and aspirin in their combination is a challenge due to the overlapping spectra of these drugs. Six smart and different spectrophotometric methods were developed for the analysis of omeprazole and aspirin in binary mixture and pharmaceutical dosage form. Read More

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February 2022

Study on the chemical changes of Quercus acuttisima by Ganoderma lucidum cultivation after different years by FTIR analysis.

Spectrochim Acta A Mol Biomol Spectrosc 2022 Feb 28;266:120443. Epub 2021 Sep 28.

Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, PR China. Electronic address:

The popularmedicinal mushroomGanodermalucidum was often cultivated by the natural-log. Generally the short log after cultivation were discarded and became pollutant. Rapid and less destructive method of analysis technical by Fourier Transform Infrared (FTIR) and Two-dimension Infrared (2DIR) correlation spectroscopy were selected to determine the composition changes of the logs after G. Read More

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February 2022

Synthesis and Characterization of Thin Films Based on Azobenzene Derivative Anchored to CeO Nanoparticle for Photoswitching Applications.

Photochem Photobiol 2021 Oct 6. Epub 2021 Oct 6.

Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany.

Azobenzene has attracted substantial attention as a photoswitchable molecule since its applications range from energy and data storage to biomedical applications. This work reports a new type of thin-film based on azobenzene derivative anchored to cerium oxide nanoparticles CeO NPs for photoswitching applications. The trans-cis isomerization and reverse isomerization occur by UV-light exposure and thermal relaxation process, respectively. Read More

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October 2021

Facile Preparation of a Rhodamine B Derivative-Based Fluorescent Probe for Visual Detection of Iron Ions.

ACS Omega 2021 Sep 17;6(38):25040-25048. Epub 2021 Sep 17.

Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, 438 West Hebei Street, Qinhuangdao 066004, P. R. China.

Iron ions play an important role in our lives. Excessive or lack of iron ion intake leads to many diseases. At the same time, the water environment is easily polluted by these metal ions with the acceleration of industrialization. Read More

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September 2021