Time-gated optical imaging through turbid media using stimulated Raman scattering: studies on image contrast

In this paper, we report the development of experimental set-up for time-gated optical imaging through turbid media using stimulated Raman scattering. Our studies on the contrast of time-gated images show that for a given optical thickness, the image contrast is better for sample with lower scattering coefficient and higher physical thickness, and that the contrast improves with decreasing value of anisotropy parameters of the scatterers. These results are consistent with time-resolved Monte Carlo simulations

Non-invasive ophthalmic imaging of adult zebrafish eye using optical coherence tomography

We describe the development of a single-mode fibre based optical coherence tomography set-up and its use for non-invasive optical imaging of adult zebrafish (Danio rerio) eyes. The free-space axial and lateral resolutions of the set-up were estimated to be ~ 11 and 17 μm respectively. Images of whole eye, cornea and retina acquired with the set-up have been used to estimate several ocular parameters, viz. corneal thickness, mean retinal thickness and effective refractive index of the crystalline lens

Tamm plasmon polariton in planar structures: A brief overview and applications

Tamm plasmon provides a new avenue in plasmonics of interface states in planar multilayer structures due to its strong light matter interaction. This article reviews the research and development in Tamm plasmon polariton excited at the interface of a metal and a distributed Bragg reflector. Tamm plasmon offers an easy planar solution compared to patterned surface plasmon devices with huge field enhancement at the interface and does not require of any phase matching method for its excitation. The ease of depositing multilayer thin film stacks, direct optical excitation, and high-Q modes make Tamm plasmons an attractive field of research with potential practical applications. The basic properties of the Tamm plasmon modes including its dispersion, effect of different plasmon active metals, coupling with other resonant modes and their polarization splitting, and tunability of Tamm plasmon coupled hybrid modes under externally applied stimuli have been discussed. The application of Tamm plasmon modes in lasers, hot electron photodetectors, perfect absorbers, thermal emitters, light emitting devices, and sensors have also been discussed in detail. This review covers all the major advancements in this field over the last fifteen years with special emphasis on the application part

Non-developing ascospores in apothecia of asexually reproducing lichen-forming fungi

The presence of apothecia in mixed species (vegetatively reproducing lichens, occasionally producing ascomata) has been interpreted as a mechanism to increase genetic variability in mostly clonal populations. However, spore viability from these apothecia has not been studied. We asked whether ascospores of the mixed species Physconia grisea are viable and thereby contribute to increasing the genetic diversity within populations of this species. An ontogenetic study of spores in cultures of P. grisea and a related sexual species (P. distorta), showed that although mature apothecia from both species produced and discharged meiospores capable of germination, spores from P. grisea were only rarely (0.43 %) able to continue development whereas those from P. distorta germinated and developed successfully. The strongly reduced viability of P. grisea spores suggested that they do not have a strong reproductive function, at least in the two local populations analyzed. Additionally, we show that the segregation of Physconia grisea ssp. lilacina does not have molecular support. [Int Microbiol 2013; 16(3):XXX-XXX]Keywords: Physconia spp. · apothecia · sexual reproduction · germination · ontogenetic development · mixed specie

General discussion on dimming control method used for discharge lamp

Author name used in this publication: P. DongAuthor name used in this publication: K. W. E. ChengAuthor name used in this publication: S. L. HoAuthor name used in this publication: D. H. WangAuthor name used in this publication: K. DingPower Electronics Research CentreRefereed conference paper2006-2007 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Origin and Diversification of Major Clades in Parmelioid Lichens (Parmeliaceae, Ascomycota) during the Paleogene Inferred by Bayesian Analysis

There is a long-standing debate on the extent of vicariance and long-distance dispersal events to explain the current distribution of organisms, especially in those with small diaspores potentially prone to long-distance dispersal. Age estimates of clades play a crucial role in evaluating the impact of these processes. The aim of this study is to understand the evolutionary history of the largest clade of macrolichens, the parmelioid lichens (Parmeliaceae, Lecanoromycetes, Ascomycota) by dating the origin of the group and its major lineages. They have a worldwide distribution with centers of distribution in the Neo- and Paleotropics, and semi-arid subtropical regions of the Southern Hemisphere. Phylogenetic analyses were performed using DNA sequences of nuLSU and mtSSU rDNA, and the protein-coding RPB1 gene. The three DNA regions had different evolutionary rates: RPB1 gave a rate two to four times higher than nuLSU and mtSSU. Divergence times of the major clades were estimated with partitioned BEAST analyses allowing different rates for each DNA region and using a relaxed clock model. Three calibrations points were used to date the tree: an inferred age at the stem of Lecanoromycetes, and two dated fossils: Parmelia in the parmelioid group, and Alectoria. Palaeoclimatic conditions and the palaeogeological area cladogram were compared to the dated phylogeny of parmelioid. The parmelioid group diversified around the K/T boundary, and the major clades diverged during the Eocene and Oligocene. The radiation of the genera occurred through globally changing climatic condition of the early Oligocene, Miocene and early Pliocene. The estimated divergence times are consistent with long-distance dispersal events being the major factor to explain the biogeographical distribution patterns of Southern Hemisphere parmelioids, especially for Africa-Australia disjunctions, because the sequential break-up of Gondwana started much earlier than the origin of these clades. However, our data cannot reject vicariance to explain South America-Australia disjunctions

Remedial Prospective of Hippophae rhamnoides Linn. (Sea Buckthorn)

Sea buckthorn (Hippophae rhamnoides L.) constitutes thorny nitrogen fixing deciduous shrub. Sea buckthorn(SBT) is primarily valued for its very rich vitamins A, B1, B12, C, E, K, and P; flavonoids, lycopene, carotenoids, and phytosterols. and therapeutically important since it is rich with potent antioxidants. Scientifically evaluated pharmacological actions of SBT are like inflammation inhibited by reduced permeability, loss of follicular aggregation of lymphocytes from the inflamed synovium and suppress lymphocyte proliferation. SBT-reduced recurrence of angina, ischemic electrocardiogram which might be due to decreased myocardial oxygen consumption and inhibition of platelet aggregation induced by collagen. SBT can kill both cancer cells of S180, P388, SGC7901 and lymphatic leukemia (L1200). The antiulcer activity may be related to reduce gastric empty time, inhibiting proteolytic activity and promoting wound reparation processes of mucosa. SBT exerts antihypertensive effect in part by blocking angiotensin-2 receptor on cell surface. SBT decreased the level of stress hormones and enhanced hypoxic tolerance in animals indicating its anti-stress, adaptogenic activity. A lot of research work is still needed to find cellular and molecular mechanisms of these activities and also yet to be explored for its activity in osteoporosis, hemorrhage, cataract, urinary stone, acne, psoriasis, polyneuritis, cheilosis, glossities, baldness, anti-obesity, gout, and chronic prostitis

A novel single-phase voltage sag restorer with diode-clamped multilevel bridge

Author name used in this publication: K. DingAuthor name used in this publication: K. W. E. ChengAuthor name used in this publication: X. D. XueAuthor name used in this publication: C. D. XuVersion of RecordPublishe