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Alexandra Alimova A. Katz Rakhi Podder Glenn Minko Hul Wei R. R. Alfano Paul Gottlieb 《Photochemistry and photobiology》2004,80(1):41-46
Native fluorescence spectroscopy was used for in situ investigations of two lipid‐containing bacteriophages from the cystovirus family as well as their Pseudomonad host cells. Both the viruses φ6 and φ12 and their bacterial host proteins contain the amino acid tryptophan (trp), which is the predominant fluorophore in UV. Within proteins, trp's structural environment differs, and the differences are reflected in their spectroscopic signatures. It was observed that the peak of the trp emission from both viruses was at 330 nm, a significantly shorter wavelength than trp in either the Pseudomonad host cells or the amino acid's chemical form. This allowed us to monitor the viral attachment process and subsequent lytic release of progeny virus particles by measurement of the trp emission spectra during the infection process. This work demonstrates that fluorescence may offer a novel tool to detect viruses and monitor viral infection of cells and may be part of a biodefense application. 相似文献
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Soo Yeon Kim Arup Podder Hyunseung Lee Youn-Joo Cho Eun Hee Han Sabina Khatun Jonathan L. Sessler Kwan Soo Hong Sankarprasad Bhuniya 《Chemical science》2020,11(36):9875
Abnormal anaerobic metabolism leads to a lowering of the pH of many tumours, both within specific intracellular organelles and in the surrounding extracellular regions. Information relating to pH-fluctuations in cells and tissues could aid in the identification of neoplastic lesions and in understanding the determinants of carcinogenesis. Here we report an amphiphilic fluorescent pH probe (CS-1) that, as a result of its temporal motion, provides pH-related information in cancer cell membranes and selected intracellular organelles without the need for specific tumour targeting. Time-dependent cell imaging studies reveal that CS-1 localizes within the cancer cell-membrane about 20 min post-incubation. This is followed by migration to the lysosomes at 30 min before being taken up in the mitochondria after about 60 min. Probe CS-1 can selectively label cancer cells and 3D cancer spheroids and be readily observed using the green fluorescence channel (λem = 532 nm). In contrast, CS-1 only labels normal cells marginally, with relatively low Pearson''s correlation coefficients being found when co-incubated with standard intracellular organelle probes. Both in vivo and ex vivo experiments provide support for the suggestion that CS-1 acts as a fluorescent label for the periphery of tumours, an effect ascribed to proton-induced aggregation. A much lower response is seen for muscle and liver. Based on the present results, we propose that sensors such as CS-1 may have a role to play in the clinical and pathological detection of tumour tissues or serve as guiding aids for surgery.A self-assembled amphiphilic fluorescent probe allows pH-fluctuations within cancer cells and tumour tissues to be readily detected. 相似文献
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Summary Light-scattering behaviour of polyvinyl pyridine and silver nitrate mixture in alcohol showed that the system behaves like a poly-electrolyte. This has been explained by the structure of the pyridine-silver complex that has been known for quite some time. 相似文献
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M. S. Podder 《Composite Interfaces》2016,23(4):327-372
The granular activated carbon/MnFe2O4 composite with a mass ratio of 2:1 was synthesized using a simple chemical coprecipitation procedure and used for the removal of As(III) and As(V) from synthetically prepared wastewater. Physicochemical analysis of the composite was carried out through Brunauer, Emmett and Teller surface area and total pore volume, Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Micrograph and Energy-Dispersive X-Ray Spectroscopy (SEM-EDX). The impact of various adsorption parameters such as the initial pH, adsorbent dose, contact time, temperature and initial arsenic concentration were systematically investigated to evaluate the optimum operating conditions. Nonlinear regression analysis was employed to identify the best-fit isotherm on the basis of three correlation coefficients and three error functions and also to predict the parameters involved in one one-parameter, six two-parameter, nineteen three-parameter, three four-parameter and one five-parameter isotherms. The maximum adsorption capacities estimated using the Langmuir model were 1253 mg/g for As(III) and 1314 mg/g for As(V) at 30 °C temperature and 70 min contact time. The results showed that As(III) and As(V) removal was strongly pH-dependent with an optimum pH value of 7.0 and 4.0, respectively. The mean adsorption energy (E) calculated from the D–R model indicated the nature of adsorption being ion exchange type. 相似文献
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Podder Soumik Halder Suman Roychowdhury Anirban Das Dipankar Ghosh Chandan Kr. 《Journal of nanoparticle research》2016,18(10):1-13
Journal of Nanoparticle Research - With the widespread use of titanium dioxide (TiO2) human exposure is inevitable, but the exposure data on TiO2 are still limited. This study adopted off-line... 相似文献
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Podder N.K. Mezonlin E.-D. Johnson J.S. III 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2001,29(6):965-969
A microwave plasma in argon is generated inside a pyrex tube by a 3-kW power supply in combination with a magnetron, wave guide, and a resonant cavity. The gas pressure is varied from 200 to 2000 mtorr, and the microwave output power is varied from 600 to 1200 W. Plasma parameters are determined by using a single Langmuir probe. Bias voltage and current characteristic curves are analyzed for the determination of electron temperature, density, and plasma potential. Electron density is found to be in the range of 1.4-7.6 × 1011 cm-3 , electron temperature 4.2-6.2 eV, and plasma potential 22.6-35.6 volts. Turbulence in plasma emissions can now be studied in these various regimes using Ar I lines 相似文献
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