Search Results (16)

The subject of this study is the interaction between 5,10,15,20-tetrakis (4-sulfonatophenyl)–porphyrin (TSPP), a potential photosensitizer for photodynamic therapy (PDT) and radiotherapy, and human serum albumin (HSA), a crucial protein in the body. The main objective was to investigate the binding mechanisms, structural changes, and potential implications of these interactions for drug delivery and therapeutic applications. Spectroscopic techniques and computational methods were employed to investigate the mechanism and effects of TSPP binding by HSA. The results suggest the possibility of simultaneous binding of three TSPP ions at binding sites of different affinity within albumin. The estimated values of the binding constant K_b for these sites were in the range of 0.6 to 6.6 μM⁻¹. Laser flash photolysis indicated the stabilization of TSPP in the HSA structure, which resulted in prolonged lifetimes of the excited states (singlet and triplet) of porphyrin. Circular dichroism analysis was used to assess the changes in the secondary and tertiary structures of HSA upon TSPP binding. An analysis of the molecular docking results allowed us to identify the preferred TSPP binding sites within HSA and provided information on the specific interactions of amino acids involved in the stabilization of TSPP–HSA complexes. The estimated free energy of the binding of porphyrin at the three most favorable docking sites found in the HSA structure that was considered native were in the range of −80 to −41 kcal/mol. Finally, thermal unfolding studies showed that TSPP increased the stability of the secondary structure of albumin. All these findings contribute to the understanding of the interactions between TSPP and HSA, offering valuable insights for the development of novel cancer therapy approaches. Full article

This study analyzed the diversity of major yield traits and nutritional components across 122 chickpea breeding lines, cultivars, and landraces of different origins. All parameters showed significant variations, with a variance ranging from 4.61% in days to maturity (DM) to 43.04% in oleic acid. Six accessions, including CP021, CP022, CP026, CP037, CP066, and CP109, outperformed in yield traits and nutritional value. Origin significantly affected all phenotypic traits except total fatty acid contents, with Indian and Ukrainian accessions demonstrating contrasting performances. Most traits, except for the number of seeds per pod (SPP), palmitic acid, and total fatty acid contents, differed significantly among breeding lines, cultivars, and landraces. Breeding lines were the earliest to flower and to mature with average days to flowering (DF) of 50.23 days and DM of 101.50 days. They also had the highest average SPP, number of pods per plant (PPP), total seeds per plant (TSPP), total protein, crude fiber, dietary fiber, linoleic acid, and linolenic acid contents making them preferable for high yield and nutrition. Hierarchical cluster analysis classified the chickpea accessions into seven clusters, showing significant variations in yield traits and nutritional components. Principal component and Pearson’s correlation analyses indicated positive correlations between DM and DF, and between SPP, PPP, and TSPP. Nutritional components also displayed varying associations, with a notable negative correlation between oleic and linoleic acids, the two essential fatty acids. Overall, this study showed the diversity of key phenotypic traits in chickpea breeding lines, cultivars, and landraces of different origins. The significant effects of genotype and origin differences on these traits could be used as a basis for future metabolomics and genomics research. Full article

The aim of the study was to compare the effects and mechanism of tetrasodium pyrophosphate (TSPP) and sodium tripolyphosphate (STPP) as dispersants on the selective flotation of arsenopyrite from muscovite. The results of single-mineral flotation showed that the recovery of arsenopyrite was 81.4% when no dispersant was added. The recovery of arsenopyrite slightly decreased with increasing dosage of TSPP. When the dosage of STPP was 6 × 10⁻⁵ mol/L, the recovery of arsenopyrite was only 28.6%. Neither of the dispersants had significant influence on the muscovite flotation (<10%). However, in a mixed-mineral system, the recovery of arsenopyrite dropped significantly, and then under the action of dispersants, its recovery back up. The RPM results showed that the dispersion effect of TSPP was superior to that of STPP. The electrokinetic potential showed that the potential change value of muscovite with TSPP was −17.37 mV, while that of muscovite with STPP was −8.33 mV (pH = 8). The adsorption of TSPP onto muscovite was stronger than that of STPP. FTIR and XPS analysis confirmed that dispersants exhibited chemical adsorption with the Al atoms on muscovite and that dispersant STPP exhibited stonger adsorption than TSPP on arsenopyrite, which was consistent with flotation experiments. Full article

In this study, organo-inorganic nanohybrids LHGd-MTSPP with enzyme-like activity were prepared by in situ intercalation of anionic 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin and its complexes with Zn(II) and Pd(II) (MTSPP, M = 2H, Zn(II) and Pd(II)) into gadolinium layered hydroxide (LHGd). The combination of powder XRD, CHNS analysis, FT-IR, EDX, and TG confirmed the layered structure of the reaction products. The basal interplanar distances in LHGd-MTSPP samples were 22.3–22.6 Å, corresponding to the size of an intercalated tetrapyrrole molecule. According to SEM data, LHGd-MTSPP hybrids consisted of individual lamellar nanoparticles 20–50 nm in thickness. The enzyme-like activity of individual constituents, LHGd-Cl and sulfoporphyrins TSPP, ZnTSPP and PdTSPP, and hybrid LHGd-MTSPP materials, was studied by chemiluminescence analysis using the ABAP/luminol system in phosphate buffer solution. All the individual porphyrins exhibited dose-dependent antioxidant properties with respect to alkylperoxyl radicals at pH 7.4. The intercalation of free base TSPP porphyrin into the LHGd preserved the radical scavenging properties of the product. Conversely, in LHGd-MTSPP samples containing Zn(II) and Pd(II) complexes, the antioxidant properties of the porphyrins changed to dose-dependent prooxidant activity. Thus, an efficient approach to the design and synthesis of advanced LHGd-MTSPP materials with switchable enzyme-like activity was developed. Full article

The combination of a metallated porphyrin, Pt(II)-5,10,15,20-tetrakis-(4-allyloxyphenyl)-porphyrin (Pt-allyloxyPP), and a water-soluble porphyrin, 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TSPP), leads to the formation of a porphyrin hetero-trimer. The hetero-trimer, consisting of two TSPP molecules linked via oxygen atoms axially to the platinum atom in the Pt-allyloxyPP molecule, was characterized by UV–Vis, FT-IR, fluorescence, and ¹H-NMR spectroscopy, and the proposed structure was confirmed. The new porphyrin hetero-trimer offers both the advantage of enhanced fluorescence and the presence of multiple sites for the detection of toluidine blue, due to its high affinity for acidic binding sites. This work brings attention to the purposely designed fluorescent sensor for toluidine blue, in the biologically relevant concentration domain of 1.9 × 10⁻⁶–6.39 × 10⁻⁵ M, with a very good accuracy. Full article

The combined method of treating malignant neoplasms using photodynamic therapy and chemotherapy is undoubtedly a promising and highly effective treatment method. The development and establishment of photodynamic cancer therapy is closely related to the creation of sensitizers based on porphyrins. The present study is devoted to the investigation of the spectroscopic, aggregation, and solubilization properties of the supramolecular system based on 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TSPP) and lanthanum-containing surfactant (LaSurf) in an aqueous medium. The latter is a complex of lanthanum nitrate and two cationic amphiphilic molecules of 4-aza-1-hexadecylazoniabicyclo[2.2.2]octane bromide. The mixed TSPP–LaSurf complexes can spontaneously assemble into various nanostructures capable of binding the anticancer drug cisplatin. Morphological behavior, stability, and ability to drug binding of nanostructures can be tailored by varying the molar ratio and the concentration of components. The guest binding is shown to be additional factor controlling structural rearrangements and properties of the supramolecular TSPP–LaSurf complexes. Full article

Heavy-haul railway transport is a critical mode of regional bulk cargo transport. It dramatically improves the freight transport capacity of railway lines by combining several unit trains into one combined train. In order to improve the efficiency of the heavy-haul transport system and reduce the transportation cost, a critical problem involves arranging the combination scheme in the combination station (CBS) and scheduling the train timetable along the trains’ journey. With this consideration, this paper establishes two integer programming models in stages involving the train service plan problem (TSPP) model and train timetabling problem (TTP) model. The TSPP model aims to obtain a train service plan according to the freight demands by minimizing the operation cost. Based on the train service plan, the TTP model is to simultaneously schedule the combination scheme and train timetable, considering the utilization optimal for the CBS. Then, an effective hybrid genetic algorithm (HGA) is designed to solve the model and obtain the combination scheme and train timetable. Finally, some experiments are implemented to illustrate the feasibility of the proposed approaches and demonstrate the effectiveness of the HGA. Full article

The detection of chemical substances excreted from the human body offers an attractive approach for non-invasive, early diagnostics of certain diseases. In this preliminary study, we proposed a susceptible optical sensor capable of quantitatively detecting ammonia from exhaled breath. The proposed sensor consists of nanoassembled ultrathin films composed of tetrakis(4-sulfophenyl)porphine (TSPP) and poly(diallyldimethylammonium chloride) (PDDA) deposited on quartz substrates using a layer-by-layer method. Measurement principles are based on the ammonia-induced absorbance changes at 489 (Soret band) and 702 nm (Q band), associated with the deprotonation of the J-aggregated TSPPs inside the film. Before exposure to breath, the PDDA/TSPP thin film was calibrated using known concentrations of ammonia gases with a projected detection limit of 102 ± 12 parts per billion (ppb). Calibrated sensor films were then exposed to human breath and urine samples to determine the ammonia concentration. Concentrations of exhaled ammonia are influenced significantly by the consumption of food or the amount of urea. Sensor response and maximum sensitivity, obtained from the absorbance changes induced by ammonia, were achieved by initial sensor exposure to HCl vapor. Previously reported procedures for the Helicobacter pylori (HELIC Ammonia Breath) test based on urea reaction with urease were reproduced using the proposed sensor. The observed behavior corresponded very well with the kinetics of the interactions between urea and urease, i.e., ammonia reached a maximum concentration approximately 5 min after the start of the reaction. A large-scale study involving 41 healthy volunteers in their 20s to 60s was successfully conducted to test the capabilities of the sensor to determine the concentration of exhaled ammonia. The concentration of ammonia for the healthy volunteers ranged between 0.3 and 1.5 ppm, with a mean value of ca. 520 ppb in the morning (before eating) and ca. 420 ppb in the afternoon (immediately after eating). These real-test mean values are meaningful when considered against the projected LOD. Full article

Ammonia gas sensors were fabricated via layer-by-layer (LbL) deposition of diazo resin (DAR) and a binary mixture of tetrakis(4-sulfophenyl)porphine (TSPP) and poly(styrene sulfonate) (PSS) onto the core of a multimode U-bent optical fiber. The penetration of light transferred into the evanescent field was enhanced by stripping the polymer cladding and coating the fiber core. The electrostatic interaction between the diazonium ion in DAR and the sulfonate residues in TSPP and PSS was converted into covalent bonds using UV irradiation. The photoreaction between the layers was confirmed by UV-vis and Fourier transform infrared spectroscopy. The sensitivity of the optical fiber sensors to ammonia was linear when exposed to ammonia gases generated from aqueous ammonia solutions at a concentration of approximately 17 parts per million (ppm). This linearity extended up to 50 ppm when the exposure time (30 s) was shortened. The response and recovery times were reduced to 30 s with a 5-cycle DAR/TSPP+PSS (as a mixture of 1 mM TSPP and 0.025 wt% PSS in water) film sensor. The limit of detection (LOD) of the optimized sensor was estimated to be 0.31 ppm for ammonia in solution, corresponding to approximately 0.03 ppm of ammonia gas. It is hypothesized that the presence of the hydrophobic moiety of PSS in the matrix suppressed the effects of humidity on the sensor response. The sensor response was stable and reproducible over seven days. The PSS-containing U-bent fiber sensor also showed superior sensitivity to ammonia when examined alongside amine and non-amine analytes. Full article

Photodynamic inactivation is known as a new antimicrobial photodynamic therapy (aPDT). It is based on the administration of a photosensitizer located in the bacterial/viral cell followed by exposure to light radiations (with a proper wavelength corresponding with the maximum value of absorption of the photosensitizer) that generate singlet oxygen or reactive oxygen species, which lead to the death of different microorganisms. This review will present an overview beyond the state-of-the-art of the photosensitizer types (based on tetra-p-sulphonated-phenyl porphyrin—TSPP, which is able to form cationic and J-aggregates forms at different pH values ((1–4) and concentrations around 10⁻⁵ M) and their applications of PDT for viruses, especially. The mechanism of dicationic and J-aggregates formation is presented in this paper, and the photophysical parameters have been collected and harmonized to support their behaviours. Studies on Herpes Simplex virus type 1 (HSV-1) are useful, because without the help of HSV-1, the COVID-19 virus may not be able to cause serious illness or death in humans. This method could be a new direction for COVID treatment and immunization, either to prevent infections or to develop photoactive fabrics (e.g., masks, suits, gloves) to disinfect surfaces, under artificial light and/or natural sunlight. The use of photodynamic therapy (PDT) can be an alternative approach against SARS-CoV-2 that deserves to be explored. Full article

Biomimetic oxidation of drugs catalyzed by metalloporphyrins can be a novel and promising way for the effective and sustainable synthesis of drug metabolites. The immobilization of 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)iron(II) porphyrin (FeTPFP) and 5,10,15,20-tetrakis-(4-sulfonatophenyl)iron(II) porphyrin (FeTSPP) via stable covalent or rapid ionic binding on aminopropyl-functionalized magnetic nanoparticles (MNPs-NH₂) were developed. These immobilized catalysts could be efficiently applied for the synthesis of new pharmaceutically active derivatives and liver related phase I oxidative major metabolite of an antiarrhythmic drug, amiodarone integrated in a continuous-flow magnetic chip reactor (Magnechip). Full article

Studying the interaction between demand forecasting and train stop planning is important, as it ensures the sustainable development of high-speed rail (HSR). Forecasting the demand for high-speed rail (HSR), which refers to modal choice or modal split in this paper, is the first step in high-speed rail (HSR) planning. Given the travel demand and the number of train trips on each route, the train stop planning problem (TSPP) of line planning involves determining the stations at which each train trip stops, i.e., the stop-schedule of each train trip, so that the demand can be satisfied. To integrate and formulate the two problems, i.e., the modal choice problem (MCP) and train stop planning problem (TSPP), a nonlinear model is presented with the objective of maximizing the total demand captured by a high-speed rail system. To solve the model, a heuristic iterative algorithm is developed. To study the relationship between the demand and the service, the Beijing–Shanghai high-speed rail (HSR) corridor in China is selected. The empirical analysis indicates that combining modal choice and train stop planning should be considered for the sustainable design of high-speed rail (HSR) train services. Furthermore, the model simulates the impact of the number of stops on its mode share by reflecting changes in travelers’ behaviors according to HSR train stop planning, and it also provides a theoretical basis for the evaluation of the adaptability of the service network to travel demand. Full article

Image similarity measurement is a fundamental problem in the field of computer vision. It is widely used in image classification, object detection, image retrieval, and other fields, mostly through Siamese or triplet networks. These networks consist of two or three identical branches of convolutional neural network (CNN) and share their weights to obtain the high-level image feature representations so that similar images are mapped close to each other in the feature space, and dissimilar image pairs are mapped far from each other. Especially, the triplet network is known as the state-of-the-art method on image similarity measurement. However, the basic CNN can only handle fixed-size images. If we obtain a fixed size image via cutting or scaling, the information of the image will be lost and the recognition accuracy will be reduced. To solve the problem, this paper has proposed the triplet spatial pyramid pooling network (TSPP-Net) through combing the triplet convolution neural network with the spatial pyramid pooling. Additionally, we propose an improved triplet loss function, so that the network model can realize twice distance learning by only inputting three samples at one time. Through the theoretical analysis and experiments, it is proved that the TSPP-Net model and the improved triple loss function can improve the generalization ability and the accuracy of image similarity measurement algorithm. Full article

Human epidermal growth factor receptor 2 (HER2) is a key tumor marker for several common and deadly cancers. It is of great importance to develop efficient detection methods for its over-expression. In this work, an electrochemical impedance spectroscopy (EIS) method adjustable by anionic porphyrin for HER2 gene detection has been proposed, based on the impedance difference between multi-walled carbon nanotubes (MWCNTs) and DNA. The interesting finding herein is that with the addition of anionic porphyrin, i.e., meso-tetra(4-sulfophenyl)-porphyrin (TSPP), the impedance value obtained at a glass carbon electrode (GCE) modified with MWCNTs and a single stranded DNA (ssDNA), the probe DNA that might be assembled tightly onto MWCNTs through π-π stacking interaction, gets a slight decrease; however, the impedance value from a GCE modified with MWCNTs and a double stranded DNA (dsDNA), the hybrid of the probe DNA with a target DNA, which might be assembled loosely onto MWCNTs for the screening effect of phosphate backbones in dsDNA, gets an obvious decrease. The reason may be that on the one hand, being rich in negative sulfonate groups, TSPP will try to push DNA far away from CNTs surface due to its strong electrostatic repulsion towards DNA; on the other hand, rich in planar phenyl or pyrrole rings, TSPP will compete with DNA for the surface of CNTs since it can also be assembled onto CNTs through conjugative interactions. In this way, the “loosely assembled” dsDNA will be repelled by this anionic porphyrin and released off CNTs surface much more than the “tightly assembled” ssDNA, leading to a bigger difference in the impedance value between dsDNA and ssDNA. Thus, through the amplification effect of TSPP on the impedance difference, the perfectly matched target DNA could be easily determined by EIS without any label. Under the optimized experimental conditions, this electrochemical sensor shows an excellent linear response to target DNA in a concentration range of 2.0 × 10⁻¹¹–2.0 × 10⁻⁶ M with a limit of detection (LOD) of 6.34 × 10⁻¹¹ M (S/N = 3). This abnormally sensitive electrochemical sensing performance resulting from anionic porphyrin for DNA sequences specific to HER2 gene will offer considerable promise for tumor diagnosis and treatment. Full article

Density functional theory (DFT and time-dependent-DFT (TD-DFT) were employed to investigate the vibroelectronic structural properties of porphyrin and some derivatives: unsubstituted porphyrin (TPyr), meso-tetraphenylporphyrin (TPP), meso-tetrakis(p-sulfonatophenyl)porphyrin (TSPP), protonated-TPyr (H₂TPyr), deuterated-H₂TPyr (D₄TPyr), protonated-TPP (H₂TPP) and deuterated-H₂TPP (D₄TPP), protonated TSPP (H₂TSPP), deuterated-H₂TSPP (D₄TSPP), dicationic TSPP (H₆TSPP) and deuterated-H₆TSPP (D₈TSPP). The possible internal conversion (IC) and intersystem crossing (ISC) processes of these compounds were investigated. Finally, the relaxed ground state potential energy surface (PES) (S₀), and singlet (S_n, n = 1–24) and triplet (T_n) excited state PESs of the TSPP molecule were calculated as function of the dihedral angle (C_α-C_m-C_ϕ-C(ph)) rotation. The results of the calculations indicated that while the meso-substitutions caused a significant shift in frequencies when the meso-carbons within the parent-porphine (or TPyr) are involved in the vibrational motion of molecules; the protonation of the N atoms at the porphine/porphyrin core causes a significant blue shift when the H on the N atoms within the pyrroline are dominantly involved in the vibrational motions. The deuteration of N atoms not only caused a red-shift in the frequencies of the corresponding peaks below 1600 cm⁻¹, but also produced new vibrational modes of frequencies in the 2565–2595 cm⁻¹ range caused by the N-D bond stretching. Similarly, the deuteration of O atoms within the sulfonato groups (-SO₃⁻) exhibited a new peak at around 2642 cm⁻¹ due to O-D bond stretching. The measured Raman spectrum of the H₂TSPP is assigned based on the predicted Raman spectra of the compounds studied here and measured Raman spectrum of the TPP (from our previous work). The IR spectrum is assigned based on our calculations and measured IR spectra obtained from the literature. The results of the TD-DFT calculations did not only indicate that the meso-substitution and protonation of the porphyrin bring about a significant read shift in the electronic transitions; but also provided a strong evidence for the IC from the Soret band to Q-bands beside possibility of the ISC process; its existence depend on the other excited state process such as much faster vibrational relaxation; the IC and etc. The ground state PES curve (S₀) of the ionic TSPP exhibited two minima at the dihedral angle (C_α-C_m-C_ϕ-C) of about 66° (corresponds to the lowest ground state) and 110° (corresponds to next energetically stable state or the local minima). The energy deference between these two minima is 0.0132 eV (or 106 cm⁻¹) and the highest potential energy barrier when undergoing from the lowest ground state to this local state is only 0.0219 eV (177 cm⁻¹; which is compatible with the thermal energy (kT) at 298 K is 207.2 cm⁻¹. Full article