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Polyphosphazenes was synthesized and their self assembly behavior was observed as reported in our previous work [1–5]. A number of experiments were carried out to study the polymerization behavior at various conditions of the polymerization time and temperature. The experimental data were analyzed by graphical and statistical methods and it was found that the polymerization phenomena was controlled by the synthesis time, i.e. Mw = Mo ek s ts, where Mw is molecular weight of the polymer at time ts, M 0(=203.24) is pre-exponential factor in the model and ks is (=10686) is synthesis rate constant for the polymer.

Applications of polyphosphazenes are gaining attention in biomedical industry due to their unique characteristics of being easily degradable. This has been achieved by the replacement of chloro groups with appropriate nucleophiles. In our present study, we have synthesized a degradable polyphosphazene by the replacement of chloro groups with 2-(2-methoxyethoxy) ethanol having controlled molecular weight. Synthesis of poly[bis((methoxyethoxy)ethoxy)phosphazene] (MEEP) is carried out in two steps. First step involves the synthesis of polydichlorophosphazenes (PDCP) from hexachlorocyclo triphosphazene using AlCl3 as catalyst by ring opening polymerization. In the second step, PDCP chlorines are substituted by 2(2-methoxyethoxyethoxy) moiety. The structure of synthesized MEEP is confirmed by phosphorous-31 nuclear magnetic resonance (31P NMR) and hydrogen-1 nuclear magnetic resonance (1H NMR). Molecular weight, molar mass distribution and polydispersity index are determined by Gel Permeation Chromatography (GPC). In vitro, hydrolytic degradation of the MEEP is carried at 37 °C in phosphate-buffered saline (PBS) with neutral, basic and acidic media. Moreover, the experimental data are demonstrated by statistical and graphical methods. The values of the coefficient of determination (R2) were found to be 0.9987, 0.9856 and 0.9359, respectively. The values of the coefficient indicate that the workability of the theoretically fitted models is good. Antibacterial activity of the synthesized polyphosphazene is evaluated against methicillin-resistant Staphylococcus aureus. The potential applications of present study are applicable for biomedical applications such as drug delivery.

Human glioma is a highly fatal tumor with a significant feature of immune suppression. The functions of PD-L1 refer to co-simulation and immune regulation. To investigate expression and functional activity of PD-L1 in human glioma cell in vivo and in vitro. Expressions of PD-L1mRNA and protein in the human glioma cell line were analyzed with quantitative RT-PCR and flow cytometer; and then expression of PD-L1 in tissue specimens of 10 glioma patients was treated with immunohistochemical analysis; glioma cell and allogeneic CD4+ and CD8+ T cells were co-cultured, and cytokine IFN-γ, IL-2 and IL-10 in cultured supernatant fluid were determined with ELISA; upon blocking the interaction between glioma cell and the immune cell with PD-L1 monoclonal antibody (5H1), surface markers on immune cells were analyzed using flow cytometer. All human glioma cell lines constitutively expressed PD-L1, and IFN-γ induced glioma cell to highly express PD-L1. It was shown through immunohistochemical analysis that glioma specimen expressed PD-L1, while expression of PD-L1 was not observed in normal tissue and normal human brain near the tumor location. The release of IFN-γ and IL-2 was inhibited, while IL-10 was increased slightly. Glioma cell may escape from immune recognition and injury with the help of PD-L1, which is a significant pathogenic mechanism of glioma.

In recent years, scientific advancements have constantly increased at a significant rate in the field of biomedical science. Keeping this in view, the application of porphyrins and metalloporphyrins in the field of biomedical science is gaining substantial importance. Porphyrins are the most widely studied tetrapyrrole-based compounds because of their important roles in vital biological processes. The cavity of porphyrins containing four pyrrolic nitrogens is well suited for the binding majority of metal ions to form metalloporphyrins. Porphyrins and metalloporphyrins possess peculiar photochemical, photophysical, and photoredox properties which are tunable through structural modifications. Their beneficial photophysical properties, such as the long wavelength of emission and absorption, high singlet oxygen quantum yield, and low in vivo toxicity, have drawn scientists’ interest to discover new dimensions in the biomedical field. Applications of porphyrins and metalloporphyrins have been pursued in the perspective of contrast agents for magnetic resonance imaging (MRI), photodynamic therapy (PDT) of cancer, bio-imaging, and other biomedical applications. This review discusses photophysics and the photochemistry of porphyrins and their metal complexes. Secondly, it explains the current developments and mode of action for contrast agents for MRI. Moreover, the application of porphyrin and metalloporphyrin-based molecules as a photosensitizer in PDT of cancer, the mechanism of the generation of reactive oxygen species (ROS), factors that determine the efficiency of PDT, and the developments to improve this technology are delineated. The last part explores the most recent research and developments on metalloporphyrin-based materials in bio-imaging, drug delivery, and the determination of ferrochelatase in bone marrow indicating their prospective clinical applications.

Alkaloid extracts of leaves (OOL) and bark (OOB) of Ochrosia oppositifolia, as well as isoreserpiline (ISR), the major alkaloid isolated from OOL and OOB, were investigated as potential corrosion inhibitors for mild steel (MS) in 1 M HCl medium. The inhibition properties of these phytoconstituents were studied using electrochemical techniques (potentiodynamic polarization measurements and electrochemical impedance spectroscopy, EIS) and scanning electron microscopy (SEM). The results indicated that these green inhibitors effectively reduced the corrosion rate. Polarization studies showed that these inhibitors decreased the corrosion current densities by a mixed-mode mechanism. The EIS data were analyzed by an equivalent circuit model for the electrode/electrolyte interface. SEM observations confirmed the existence of an adsorbed protective film of green inhibitors, and the adsorption was found to follow the Langmuir adsorption isotherm. FTIR and molecular modeling studies were also employed and revealed t...

International audience; A new indole alkaloid; neonaucline (1), along with six known compounds-Cadamine (2), naucledine (3), harmane, benzamide, cinnamide and blumenol A-were isolated from the leaves of Ochreinauclea maingayii (Rubiaceae). In addition to that of compound 1, (13)C-NMR data of cadamine (2) and naucledine (3) were also reported. Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D- and 2D-NMR, IR, UV and LCMS-IT-TOF. The excellent vasorelaxant activity on isolated rat aorta was observed for the alkaloids 1-3 after injection of each sample at 1 × 10(-5) M.