Optical and nonlinear absorption properties of Na doped ZnO nanoparticle dispersions

We report linear and nonlinear optical properties of the biologically important Na doped ZnO nanoparticle dispersions. Interesting morphological changes involving a spherical to flowerlike transition have been observed with Na doping. Optical absorption measurements show an exciton absorption around 368 nm. Photoluminescence measurements reveal exciton recombination emission, along with shallow and deep trap emissions. The increased intensity of shallow trap emission with Na doping is attributed to oxygen deficiency and shape changes associated with doping. Nonlinear optical measurements show a predominantly two-photon induced, excited state absorption, when excited with 532 nm, 5 ns laser pulses, indicating potential optical limiting applications

Spectrally broadened excitonic absorption and enhanced optical nonlinearities in Dy3+-doped ZnO nanoparticles

We have synthesized Dy3+-doped ZnO nanoparticles at room temperature through the sol-gel method. X-ray diffraction and Scanning electron microscopic studies confirm the crystalline nature of the particles. Excitonic absorption of ZnO shows three different bands, and we observe that incorporation of Dy3+ results in the shifting and broadening of the n=1 absorption band of ZnO. Photoluminescence studies done at the excitation wavelength of 335 nm show broad emission containing five different bands. Open-aperture z-scan studies done at 532 nm using 5 ns laser pulses show an optical limiting behavior, which numerically fits to a three-photon type absorption process. The nonlinearity is essentially resonant, as it is found to increase consistently with Dy3+ concentration. This feature makes Dy3+-doped ZnO a flexible optical limiter for potential device applications

Purification of heat labile toxin from Bordetella pertussis vaccine strain 134 employed indigenous technology

Aim and objective: The aim of the study was the evaluation of purified HLT from B. pertussis vaccine strain 134 by employing indigenous technology and examining the immuno-biochemical aspects of the purified protein. Materials and methods: Shaker cultivation of B. pertussis strain 134, sterility, opacity confirmation, TCA precipitation of cellular proteins, G50 purification subsequent DEAE purification, purity analysis, specific activity of HLT, and immune response analysis. Results: The shaker cultivated B. pertussis strain 134 passed its quality attributes such as sterility, opacity and purity. During TCA precipitation the B. pertussis desired proteins were precipitated and confirmed. The indigenous bed height was optimized and recovery was also calculated in G50 purification. The fractions were analyzed for OD, the total protein concentration and the results were 0.074–0.214, and the total protein content was found between 12.33 μg/ml and 35.67 μg/ml. Subsequent DEAE purification of selected G50 fractions was done and the fractions 9 and 14 had higher OD values of 0.675 and 0.397. Furthermore the DEAE purified samples were structurally analyzed through SDS PAGE and it was found that HLT in the single polypeptide band was around 140 kDa. The qualitative immune response analysis of DEAE purified selected fractions pool showed positive immune response in ODD assay, and in the case of guinea pig antisera it led to the development of diagnostic kits such as ELISA and other vital techniques. Here, in case of guinea pig experiment, the hemorrhagic necrosis analysis showed the necrosis on the skin at the injection site. Conclusion: The B. pertussis HLT could be purified through two phase with G50 and DEAE, cost effective techniques, the G50 purification has reduced the bioburden problems during DEAE purification and at the same time the quality of the product was high

Application of Plantibodies, the Plant-MADE Vaccines

Various approaches are used to integrate the desired genes encoding the antigen protein for a given illness into the genome of plant tissues in plant-based vaccination technology. Gene transfer by agrobacterium and transformation via a genetically engineered plant virus are two typical approaches for producing efficient vaccinations. Antibodies are an important component of vertebrates' adaptive immune systems, and they may now be made by converting plants with antibody-coding genes from animals and humans. Despite the fact that plants do not produce antibodies naturally, plant-derived antibodies (plantibodies) have been proven to behave similarly to mammalian antibodies. However, as science and technology have progressed, new approaches have been created to improve the efficiency of older technologies including biolistic, electroporation, agroinfiltration, sonication, and polyethylene glycol treatment. Despite the fact that plant-based vaccinations have numerous advantages for the vaccine industry, there are still constraints that limit the rate at which these third-generation vaccines may be successfully manufactured. Despite these limitations, continued attempts are still underway to develop effective vaccines for a variety of human and animal diseases, owing to its enormous potential