Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy最新文献

In a pH 9.40 Clark-Lubs buffer solution, Vitamin B6 interacts with Fe³⁺, forming a coordination complex, increased the fluorescence signal of the reaction system. Based on the coordination reaction between Fe³⁺ and Vitamin B6, we proposed a novel method for determining Vitamin B6 content. The fluorescence intensity enhancements at 326 nm characteristic wavelength showed a linear relationship with Vitamin B6 concentrations in the range of 0.05-1.85 mg/L, with a correlation coefficient of 0.9966, and a detection limit of 0.0074 mg/L. This method was successfully applied in the determination of Vitamin B6 in tablet formulations. The proposed approach is simple, time-efffcient, cost-effective, and highly sensitive, thus suitable for the content detection of Vitamin B6.

Accurate discrimination of dark tea vintages is crucial for quality assurance and market value assessment. In this study, a multiple carbon quantum dots-enhanced excitation-emission matrix (MCQDs-EEM) fluorescence strategy was developed for the rapid identification of Anhua dark tea from different production years. Three functional carbon quantum dots with complementary responses to pH, tea polyphenols, and amino acids were combined into an integrated fluorescent chemical sensor, generating enhanced and information-rich fluorescence fingerprints upon interaction with tea infusions. The MCQDs-EEM dataset was decomposed using the Alternating Trilinear Decomposition (ATLD) algorithm, which revealed four chemically significant components that showed differences in Anhua dark tea from thirteen different years. Based on the MCQDs-EEM data, partial least squares discriminant analysis (PLS-DA) and k-nearest neighbors (k-NN) models were constructed. The PLS-DA model achieved 100% classification accuracy for both the training and test sets, while the k-NN model attained accuracies of 96.59% and 100%, respectively. These results demonstrate clear superiority over the traditional fluorescence strategy based on carbon quantum dots (CQDs-FL), which relies on the splicing of three distinct emission spectra. The MCQDs-EEM strategy not only simplifies the implementation process but also demonstrates higher accuracy, which can be regarded as an effective tool for tea vintage authentication and quality control.

Chronic Obstructive Pulmonary Disease (COPD) is a major global respiratory illness causing death and disability. Traditional methods lack consistent standards, often miss diagnoses, and cannot explore diseases' molecular relationships. Thus, there is a need for a diagnostic method that is both efficient and convenient. This study aimed to evaluate the potential of diagnosing COPD, Non-COPD (Pulmonary infection), and Healthy Group using serum fluorescence, Raman, and surface-enhanced Raman spectra (FS, RS, and SERS) algorithms combined with eight machine learning algorithms. The experiment reveals variations at each peak by examining the serum FS, RS, and SERS of COPD patients compared to the control group. The combination of serum RS or SERS with machine learning algorithms provides superior classification results compared to serum FS. Serum SERS and machine learning algorithms classify COPD and healthy individuals with over 0.98 accuracy. Serum SERS combined with the synthetic minority over-sampling technique (SMOTE) -gradient boosting (GB) algorithm achieves a three-classification accuracy of 0.84. In summary, the integration of serum SERS with SMOTE-GB machine learning techniques showed significant promise for COPD detection.

Lysosomal polarity is closely associated with its functional integrity, and its dynamic changes serve as a key indicator for assessing cellular status and the progression of various diseases. However, currently available fluorescent probes for monitoring lysosomal polarity generally suffer from small Stokes shifts and insufficient sensitivity, leading to low signal-to-noise ratios and susceptibility to auto-fluorescence interference, making it difficult to accurately track dynamic fluctuations. To address the above challenge, this study successfully developed a novel lysosome-targeted fluorescent probe PTC. PTC is ingeniously designed based on a strong intramolecular charge transfer (ICT) effect, exhibiting not only high sensitivity to the microenvironmental polarity (showing a good linear relationship between fluorescence intensity and polarity) but also a remarkably large Stokes shift (>165 nm). We successfully achieved high-fidelity imaging of lysosomal polarity, detected autophagy process, and captured in real-time the dynamic evolution of lysosome. This probe provides a powerful chemical tool for in-depth research into the molecular mechanisms of lysosome-related diseases.

As a common sulfate mineral on Martian surface, calcium sulfate hydrate experiences wide temperature variations. However, the permittivity properties of calcium sulfate hydrate as a function of temperature remains underexplored. In this study, this gap has been addressed by systematically investigating the complex permittivity of calcium sulfate dihydrate (CaSO₄·2H₂O) in THz frequency band using terahertz time-domain spectroscopy over a temperature range from 100 K to 320 K. Base on the effective medium theory of Landau-Lifshitz-Looyenga (LLL), the permittivity has been extracted from the matrix and compared with that of the calcium sulfate (CaSO₄). It is found that as the temperature increases from 100 K to 320 K, the real part and the imaginary part of the permittivity for CaSO₄·2H₂O increases from 5.3 to 5.8, and 0.25 to 0.32 at 1.0 THz, respectively. For CaSO₄, the corresponding values change from 5.2 to 5.3 and 0.28 to 0.4 respectively. The difference in the permittivity properties is mainly attributed to the temperature-dependent changes in crystal-water molecular polarizability, as well as its frequency-dependent response. Finally, to investigate the effect of solar-wind on these properties, calcium sulfate dihydrate irradiated by proton with a fluence of 2 × 10¹⁰ protons/cm² has also been measured and discussed. Following proton irradiation, at 220 K the real part of the permittivity increases approximately 0.3, while the imaginary part of the permittivity decreases about 0.2. These findings provide valuable insights into the temperature-sensitive permittivity behavior of hydrated minerals as well as to quantitatively identify minerals on the Mars.

In this study, Surface-enhanced Raman Spectroscopy (SERS) and Fourier Transform Infrared Spectroscopy (FTIR) were employed to investigate the molecular changes in Escherichia coli (E. coli) induced by exposure to ampicillin (AMP), enrofloxacin (ENR), ciprofloxacin (CIP), and norfloxacin (NFX) over time. The optimal concentration of E. coli for SERS analysis was determined to be 50 μL of bacterial suspension, diluted six times to achieve an OD600 ≈ 0.1. The primary changes in the SERS spectra were observed at 1267 cm^-1, corresponding to the amide III band in proteins, while the FTIR spectra revealed significant changes in the 1200-900 cm^-1 range, associated with carbohydrates, under AMP treatment. ENR, CIP, and NFX, which are quinolone antibiotics, act as inhibitors of DNA synthesis. The main changes in the SERS spectra for antibiotic-resistant E. coli were observed at 760 cm^-1 (attributed to cytosine and uracil), 960 cm^-1 (CN stretching and CC deformation), and 1140 cm^-1 (COC stretching and ring breathing). In the FTIR spectra, significant changes were detected at 1655 cm^-1, 1544 cm^-1, and 1239 cm^-1, corresponding to the amide I, amide II, and amide III bands, respectively. The combination of SERS and FTIR with principal component analysis (PCA) enabled the detection of molecular modifications in antibiotic-resistant E. coli exposed to different classes of antibiotics. These findings enhance our understanding of the mechanisms of action of antibiotics in bacteria.

This paper discusses about the dielectric studies of binary mixtures of paracetamol (PCM) and Diethylamine (DEA). Parallel resistance (R_p) and Parallel capacitance (C_p) measured using a precision LCR meter over a frequency range of 20 Hz-2 MHz at four distinct temperatures, starting from 293.15 K and increasing by 10 K for each subsequent measurement. These experimental parameters were used to compute the complex dielectric function, from which electrical properties like complex conductivity, complex impedance and complex electrical modulus-were derived. In addition to conventional analysis, machine learning (ML) models were implemented to predict dielectric constant (ε') and dielectric loss (ε″) values based experimental inputs, with their predictive performance significantly enhanced through Bayesian hyperparameter optimization. This dual approach of combining experimental data with ML modelling offers a novel methodology for efficient and accurate characterization of dielectric systems. The added value of this study lies in its ability to bridge physical measurements with computational predictions, reducing experimental workloads and improving generalization in similar systems. The findings have potential applications in material science, pharmaceuticals, and electronic device modelling. This study demonstrates that ML assisted dielectric analysis can serve as a powerful tool in predictive material characterization.

Pitch canker, caused by Fusarium circinatum, poses a major threat to Pinus radiata plantations, resulting in substantial economic and ecological losses. Early detection of this pathogen is crucial, as conventional methods rely on late-stage visual symptoms. This study explores the potential of visible-near-infrared hyperspectral imaging (VIS-NIR HSI) combined with multivariate techniques for the early detection of F. circinatum infection in P. radiata cuttings before symptom onset. The infection process was monitored over 57 days in two P. radiata genotypes through hyperspectral image acquisition in the 400-1000 nm range. Fast Principal Component Analysis (Fast-PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) were applied to identify key spectral variations and classify samples as infected or healthy, respectively. The results demonstrate that early differentiation between infected and healthy cuttings is possible, achieving high classification accuracy at 27 days post-inoculation (dpi) in predictive model validation. Additionally, phenotypic differences between genotypes were observed, with genotype A exhibiting earlier and more pronounced spectral changes between infected and control samples than genotype B, suggesting varying resistance levels of genotypes. These findings underscore the potential of VIS-NIR HSI for both early disease detection and the assessment of genetic susceptibility, providing valuable insights for breeding programs aimed at enhancing P. radiata resistance while establishing HSI as a powerful, non-invasive, and high-throughput phenotyping tool with applications in precision forestry and large-scale disease monitoring.

One of the most commonly prescribed medications are antithrombotic agents which consisting of antiplatelet and anticoagulant medications. Currently, millions of patients rely on them to avoid blood-clot-related issues across various cardiovascular diseases. The combined administration of apixaban, aspirin and clopidogrel is an example of this therapy which can be used for the risk reduction in cardiovascular death. The importance of such medications encourages us to investigate novel analytical assay methods for determination of such drugs in dosage forms as well as in human plasma. Spectroscopic technique was the best choice to design new analytical methods due to its applicability and simplicity. Three spectroscopic methods were introduced for concurrent determination of apixaban, aspirin and clopidogrel. The designed methods were; A direct measurement for determination of apixaban without interference from the other two drugs (method I), Ratio spectra (method II) and first derivative ratio spectra (method III). The first method enables us to determine apixaban through direct measurement of its absorption spectrum at 310 nm with no reading from aspirin or clopidogrel. Ratio spectra method (method II) was performed at ΔP = 223.6-245.2 nm for aspirin, ΔP = 293.2-307.0 nm for apixaban and ΔP = 251.0-260.0 nm for clopidogrel. The third first derivative ratio spectra method was based on measuring apixaban at 255 nm, aspirin at 242 nm and clopidogrel at 260 nm using the other two analytes as a double divisor. The linearity of the designed methods was 0.5-18 μg/mL for apixaban by the three methods while were 2.0-28 μg/mL for both aspirin and clopidogrel by method II & III. These developed approaches were effectively applied for estimation of the three studied drugs in their raw materials, synthetic mixtures and dosage forms simultaneously. The co-administration of these treatments enables us to extend the application for determination of them in spiked human plasma without complicated procedures. The applied methods were validated following the ICH Q2(R1) guidelines. The greenness of the designed methods was evaluated using six different tools including; Analytical Eco-scale, GAPI, AGREE metrics, NEMI, whiteness and blueness assessment.

In recent years, Raman spectroscopy analysis of hematological diseases is increasingly applied in research, but its application in serum analysis of myeloid neoplastic diseases represented by myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), and acute myeloid leukemia (AML) has not been fully tested. To establish an oversimplified non-invasive serum test approach for MPN, MDS/MPN and AML, we systematically examined peripheral blood serum samples from 8 patients diagnosed with MPN, 4 patients with MDS/MPN, 3 patients with AML, and 9 control participants. A laser Raman spectroscopy was utilized together with orthogonal partial least squares discriminant analysis (OPLS-DA). Next, a differentiation model for MPN, MDS/MPN, AML, and the control was constructed. Compared with the healthy participants, the serum spectral data of patients with myeloid tumors were specific, and the intensities of Raman peaks representing nucleic acids (786, 1579 cm^-1), proteins (643, 759, 1031, 1260, 1603, 1616 cm^-1), lipids (1437, 1443, 1446 cm^-1), and β-carotene (957 cm^-1) were significantly decreased, while the intensity of the Raman peak representing collagen (1345 cm^-1) was significantly increased. Metabolic serum marker analysis revealed consistent patterns across MPN, MDS/MPN, and AML patients: adenosine deaminase (ADA) levels were significantly elevated, while both total protein and low-density lipoprotein concentrations showed marked reductions compared to controls. This provides spectroscopic evidence that will guide early differentiation of massive serum test data of patients with MPN, MDS/MPN and AML, and simultaneously uncovers crucial details for rapid and rudimentary differentiating them. This exploratory study show that the Raman spectroscopy analysis is an innovative non-invasive clinical instrument for the detection of MPN, MDS/MPN and AML.