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A pH-responsive zinc (II) metalated porphyrin for enhanced photodynamic/photothermal combined cancer therapy; 一种用于增强光动力/光热协同肿瘤治疗的酸性 刺激响应锌(II)金属卟啉化合物;
摘要： The acidic tumor microenvironment is triggered by glycolysis in hypoxic condition, which can motivate the pH-responsive system to build certain triggers for efficiently tumor-targeted phototherapy. Additionally, the metalated porphyrin structures are widely studied in biomedical applications due to the favorable properties of high singlet oxygen quantum yield as well as strong fluorescence imaging ability. Herein, a pH-responsive zinc (II) metalated porphyrin (P-4) was designed and synthesized for amplifying cancer photodynamic/photothermal therapy with excellent fluorescence quantum yield (67.4%), superb singlet oxygen quantum yield (84.3%) and desired photothermal conversion efficiency (30.0%). In vitro, the self-assembled P-4 nanoparticles can specifically target to lysosome subcellular site and realize protonated process of dibutaneaminophenyl (DBAP) groups with high photo toxicity. Under single 660 nm laser illumination, the tumor can be ablated completely with no side effects in vivo. This work demonstrates that the pH-responsive P-4 nanoparticles provide a new avenue for highly efficient cancer combination therapy.
关键词： porphyrin,pH-responsive,NIR absorbance,photothermal therapy,photodynamic therapy
更新于2025-11-14 15:29:11
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Using near infrared measurements to evaluate NaCl and KCl in water
摘要： Spectral differences between aqueous solutions of NaCl and KCl have received minimal attention in previous research due to strong similarities between the two salts and the lack of motivation to differentiate between them. Correlations between salinity and absorbance have been developed previously with varying degrees of linearity but have not been tested to saturation. This work will demonstrate that correlating spectral measurements and the concentration of NaCl and KCl in water can be extended up to the saturation point of both salts and that solutions of these salts with unknown concentrations can be distinguished. Spectral data for samples of NaCl and KCl in single-salt solutions were collected up to saturation and correlations were developed for differentiating between solutions of the two species. These correlations were able to correctly identify the solution type for all solutions in the test set and estimate their concentrations with an average error of 0.9%.
关键词： spectroscopy,salinity,KCl,NaCl,water,absorbance
更新于2025-09-23 15:22:29
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Spectrophotometric and Chemometric Methods for Simultaneous Determination of Two Anti-Hypertensive Drugs in their Combined Dosage Form
摘要： In this study determination of Moexipril hydrochloride (MOX) and hydrochlorothiazide (HCT) were conducted by application of Spectrophotometric and Chemometric methods. Five different accurate, sensitive and reproducible methods were applied for the simultaneous determination of (MOX) and (HCT) in their bulk powder and pharmaceutical dosage form. The first method is the new absorbance subtraction (AS) method. The second method is the new amplitude modulation (AM) method. The third method is the new extended ratio subtraction (ERS) method coupled to ratio subtraction (RS) method. The fourth and fifth methods are multivariate calibration which includes Principal Component Regression (PCR) and Partial Least Squares (PLS). The suggested procedures were checked using laboratory prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparations. The validity of the proposed methods was further assessed by applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with a reported method.
关键词： Absorbance subtraction,Hydrochlorothiazide,chemometric methods,Moexipril hydrochloride,Extended ratio subtraction,Amplitude modulation
更新于2025-09-23 15:21:01
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Raman and infrared spectroscopic quantification of the carbonate concentration in K2CO3 aqueous solutions with water as an internal standard
摘要： Carbonate-bearing fluids widely exist in different geological settings, and play important roles in transporting some elements such as the rare earth elements. They may be trapped as large or small fluid inclusions (with the size down to <1 μm sometimes), and record critical physical-chemical signals for the formations of their host minerals. Spectroscopic methods like Raman spectroscopy and infrared spectroscopy have been proposed as effective methods to quantify the carbonate concentrations of these fluid inclusions. Although they have some great technical advantages over the conventional microthermometry method, there are still some technical difficulties to overcome before they can be routinely used to solve relevant geological problems. The typical limitations include their interlaboratory difference and poor performance on micro fluid inclusions. This study prepared standard ion-distilled water and K2CO3 aqueous solutions at different molarities (from 0.5 to 5.5 mol/L), measured densities, collected Raman and infrared spectra, and explored correlations between the K2CO3 molarity and the spectroscopic features at ambient P-T conditions. The result confirms that the Raman O-H stretching mode can be used as an internal standard to determine the carbonate concentrations despite some significant differences among the correlations, established in different laboratories, between the relative Raman intensity of the C-O symmetric stretching mode and that of the O-H stretching mode. It further reveals that the interlaboratory difference can be readily removed by performing one high-quality calibration experiment, provided that later quantifying analyses are conducted using the same Raman spectrometer with the same analytical conditions. Our infrared absorption data were collected from thin fluid films (thickness less than ~2 μm) formed by pressing the prepared solutions in a Microcompression Cell with two diamond-II plates. The data show that both the O-H stretching mode and the O-H bending mode can be used as internal standards to determine the carbonate concentrations. Since the IR signals of the C-O antisymmetric stretching vibration of the CO3 2- ion, and the O-H stretching and bending vibrations from our thin films are very strong, their relative IR absorbance intensity, if well calibrated, can be used to investigate the micron-sized carbonate-bearing aqueous fluid inclusions. This study establishes the first calibration of this kind, which may have some applications. Additionally, our spectroscopic data suggest that as the K2CO3 concentration increases the aqueous solution forms more large water molecule clusters via more intense hydrogen-bonding. This process may significantly alter the physical and chemical behavior of the fluids.
关键词： Relative IR absorbance,K2CO3 concentration,Relative Raman intensity,Carbonate aqueous solution,Micro fluid inclusion
更新于2025-09-23 15:19:57
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Selection of the confining beam for laser direct writing with scanning absorbance modulation
摘要： Absorbance-modulation optical lithography has been proposed to obtain super-resolution grating patterns with far-field optics. However, the patterns are monotonous since the interference fringes are used as the confining beam. We propose laser direct writing with scanning absorbance modulation to produce free super-resolution patterns. Four kinds of optical vortex beams are studied as the confining beam and the performance of scanning absorbance modulation using each of them is simulated. In conclusion, the selection of the best confining beam has to follow three criteria and an example is the 2-level, 1.5-order optical vortex beam.
关键词： laser direct writing,optical vortex beam,absorbance modulation
更新于2025-09-23 15:19:57
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Optical properties and zeta potential of carbon quantum dots (CQDs) dispersed nematic liquid crystal 4a?2- heptyl-4-biphenylcarbonitrile (7CB)
摘要： In this work, carbon quantum dots (CQDS) of three concentrations 0.1, 0.2 and 0.5 wt% have been dispersed in nematic liquid crystal 4-Heptyl-4-biphenylcarbonitrile (7CB). The results on the optical properties and zeta potential of pure and CQDs dispersed nematic 7CB have been reported. It has been observed that the dispersion of CQDs in host nematic matrix induces quenching of photoluminescence and reduces the Ultra-Violet-Visible (UV–Vis) absorbance of pure nematic at a lower wavelength. From the result of fluorescence decay profile, the fluorescence life time of pristine and dispersed nematic systems have been obtained. No remarkable changes in nematic lifetime in the presence of CQDs have been observed, which confirm that no energy is transferred from nematic to CQDs. Further, it has been found that due to dispersion of CQDs the numerical values of zeta potential are increased for the dispersed systems with 0.1 and 0.2 wt% concentrations of CQDs as compared to pure 7 CB. This result demonstrates that the study of zeta potential provides useful information on the stability and aggregation of the CQDs dispersed nematic systems.
关键词： Carbon quantum dots,UV–Vis absorbance,Zeta potential,Nematic liquid crystal,Time resolved fluorescence
更新于2025-09-23 15:19:57
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Plasmonic gel nanocomposites for detection of high energy electrons
摘要： Radiation therapy is a common treatment modality employed in the treatment of cancer. High energy photons are the primary source of radiation but when administered, they leave an exit dose resulting in radiation damage to the adjacent healthy tissues. To overcome this, high energy electrons are employed in cases of skin cancer to minimize radiation induced toxicity. Despite these advances, measurement of delivered radiation remains a challenge due to limitations with existing dosimeters including labor intensive fabrication, complex read-out techniques and post-irradiation instability. To overcome these limitations, we have developed a novel colorimetric plasmonic gel nanocomposite for the detection of therapeutic levels of radiation delivered in electron beam therapy. The plasmonic nanocomposite consists of an agarose gel matrix encapsulating precursor gold ions, which are reduced to gold nanoparticles as a result of exposure to high energy electrons. The formation of gold nanoparticles renders a change in color to the agarose matrix, resulting in the formation of plasmonic gel nanocomposites. The intensity of the color formed exhibits a linear relation with the delivered electron dose, which can be quantified using absorbance spectroscopy. The plasmonic gel nanocomposites were able to detect doses employed in fractionated electron therapy, including in an anthropomorphic phantom used for planning radiation treatments in the clinic. Furthermore, the use of glutathione as a quenching agent facilitated qualitative and quantitative spatial mapping of the delivered dose. Our results indicate that the ease of fabrication, simplicity of detection and quantification using absorbance spectroscopy, determination of spatial dose profiles, and relatively low cost make the plasmonic gel nanocomposite technology attractive for detecting electron doses in the clinic.
关键词： gold nanoparticles,Plasmonic gel nanocomposites,radiation therapy,high energy electrons,absorbance spectroscopy
更新于2025-09-23 15:19:57
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Surface ligation stage revealed through polarity-dependent fluorescence during perovskite nanocrystal growth
摘要： Methylammonium lead iodide perovskite (MAPbI3) nanocrystals (NCs) exhibit favorable photophysics for a range of light emitting applications. A comprehensive mechanistic understanding of the nucleation and growth processes for these NCs is still elusive. Absorbance and fluorescence spectra were measured during a NC synthesis with kinetics limited by precursor solvation using a rapid sampling technique wherein syringe filters quench NC growth. The signal from well-capped NCs in the reaction mixture was isolated by the use of polar syringe filters, enabling spectroscopic observation of the surface ligation process. Our results indicate that the formation of these NCs involves a single stage of nucleation and growth, followed by a terminal surface ligation stage.
关键词： perovskite nanocrystals,growth,nucleation,fluorescence,absorbance,surface ligation
更新于2025-09-23 15:19:57
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Study on the dependence of fluorescence intensity on optical density of solutions: the use of fluorescence observation field for inner filter effect corrections
摘要： This work reports the identification of absorbance value of an analyte, at the excitation wavelength, that corresponds to maximum of the observed fluorescence intensity obtainable for a certain instrument operating with right-angle fluorescence measurement (Aλex^max_fl). The Aλex^max_fl value depends on the fluorescence observation field (FOF) dimensions of the concerned spectrofluorometer. As the FOF varies from instrument to instrument, this work presents a simple method for obtaining FOF dimensions. With the knowledge of FOF and absorbance of analyte at the excitation wavelength (Aλex) and emission wavelength (Aλem), we deduced a derived absorbance spectral parameter (Dabs). The observed fluorescence intensity of an analyte is proportional to the Dabs. Upon differentiating Dabs w.r.t. Aλex, the value of Aλex^max_fl for the concentred spectrofluorometer is obtained and subsequently can be used for maximizing fluorescence sensitivity. It is observed that when the FOF is a point at the centre of a 1 cm path-length cuvette, the Aλex^max_fl value is 0.87; with progressive widening of FOF, the Aλex^max_fl value increases gradually till ~1. The proposed methodology is established using two well-known inner filter effect (IFE) correction models (Parker and Lakowicz model). The Dabs obtained from Parker model corresponds well with the observed fluorescence data, while the Dabs obtained using Lakowicz model overestimates the loss of fluorescence due to IFE. Using equations derived from Parker model, the correction of observed fluorescence intensity for IFE can be achieved. It is further demonstrated that the commonly used Lakowicz model loses its correction-efficiency at absorbance values ≥ 0.7.
关键词： interrogation window,Maximum fluorescence,Derived absorbance,Inner filter effect,Fluorescence observation field
更新于2025-09-19 17:15:36
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Application of barium strontium titanate (BST) as a light sensor on led lights
摘要： Barium Strontium Titanate (BST) film has been successfully produced as a light sensor. The BST film was made by CSD method by reacting barium acetate, strontium acetate and titanium isopropoxide with mole fractions of 0.5; 0.5 and 1, respectively.The BST absorbance test showed that BST film is sensitive to visible light ranging from 475 to 750 nm. The film test showed maximum absorbance at three peak wavelengths, 475 nm, 593 nm, and 702 nm. The energy gap of the BST film was 1.9 eV which showed that the film produced was a semiconductor. The IV test showed that BST film is a photodiode. This was indicated by the shift of the curve when tested in light and dark conditions. The sensitivity test showed BST film is most sensitive to blue light, signified by the most significant change in resistance. The decrease in resistance of blue LED was 0.401KX/lux, while the resistance decrease of green light was 0.051KX/lux and red was 0.288KX/lux. By using optical and electrical properties, BST thin film could be used as light sensors to detect LED lights.
关键词： semiconductor,I-V,absorbance,chemical solution deposition,Barium strontium titanate
更新于2025-09-19 17:13:59