Non-destructive insights into photosynthetic and photoprotective mechanisms in Arabidopsis thaliana grown under two light regimes.

Probing insights into understanding photosynthetic processes via non-invasive means has an added advantage when used in phenotyping or precision agriculture. We employed Raman spectroscopy and fluorescence-based methods to investigate both the changes in the photosynthetic processes and the underlying protective mechanisms on Arabidopsis thaliana wild-type (WT), and ros1, which is a mutant of a repressor of transcriptional gene silencing, both grown under low light (LL: 100 µmol m-2s-1) and high light (HL: 400 µmol m-2s-1) regimes. Raman imaging detected a lower carotenoid intensity after two weeks in those plants grown under HL, compared to those grown under the LL regime; we interpret this as the result of oxidative damage of ß-carotene molecules. Further, the data revealed a significant depletion in carotenoids with enhanced phenolics around the midrib and tip of the WT leaves, but not in the ros1. On the contrary, small necrotic zones appeared after two weeks of HL in the ros1 mutant, pointing to the starting oxidative damage. The lower maximum quantum yield of the photochemistry (Fv/Fm) in the WT as well as in the ros1 mutant grown in HL (compared to those in the LL two weeks post-exposure), indicates the HL partially inactivated photosystems. Chlorophyll a fluorescence imaging further showed high non-photochemical quenching (NPQ) in the plants grown under the HL regime for both the WT and the ros1 mutant, but the spatial heterogeneity of NPQ images was much higher in the HL-grown ros1 mutant. Fluorescence screening methods revealed significantly high values of chlorophyll proxies in the WT as well as in the ros1 mutant two weeks after in the HL compared to those under LL. The data generally revealed an increased accumulation of phenolics under HL in both the WT and ros1 mutant plants, but the proxies of anthocyanin and flavonols were significantly lower in the ros1 mutant than in the WT. The comparatively low accumulation of anthocyanin in the ros1 mutant compared to the WT supports the Raman data. We conclude that integrated use of these techniques can be efficiently applied for a better understanding of insights into photosynthetic mechanisms.

Electro-Physiology of Coupling Model and Its Impact on Naja Kaouthia Venom Treated Sciatic Nerves of Toad.

Demyelination in peripheral nerves causes dysfunction of slowing down and stoppage of nerve impulses causing many neurological diseases, such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. This paper aims to develop a recovery model having interaction of a demyelinated nerve with a normal myelinated nerve. We validated the model by coupling between peripheral nerve of toad (demyelinated with Naja kaouthia venom) and a normal nerve of toad. An increase in both nerve conduction velocity as well as compound action potential amplitude is observed in the repetition of the experiments indicating gradual recovery of the patients. The significance behind this work is to suppress the malfunctioning of the demyelinated nerve by the normal electro-physiological activity of the normal nerve for speedy recovery using coupling model. The recovery model will be used in the treatment of neurological disorders with the influence of normal neuro physiological properties of a normal adjacent nerve.

Quantifying Demyelination in NK venom treated nerve using its electric circuit model.

Reduction of myelin in peripheral nerve causes critical demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. Clinical monitoring of these diseases requires rapid and non-invasive quantification of demyelination. Here we have developed formulation of nerve conduction velocity (NCV) in terms of demyelination considering electric circuit model of a nerve having bundle of axons for its quantification from NCV measurements. This approach has been validated and demonstrated with toad nerve model treated with crude Naja kaouthia (NK) venom and also shows the effect of Phospholipase A2 and three finger neurotoxin from NK-venom on peripheral nerve. This opens future scope for non-invasive clinical measurement of demyelination.

Double S-bend structure for a compact two mode interference coupler.

A double S-bend structure has been proposed for the reduction of coupling length of the 2 × 2 two mode interference (TMI) coupler. The coupling characteristics of the proposed structure are compared with those of conventional TMI structures using a simple mathematical model based on sinusoidal modes. The longitudinal beat length for the proposed TMI coupler is reduced by 15% of the beat length of a conventional TMI coupler. The effect of power imbalance on fabrication tolerance of the proposed TMI coupler is also studied and compared with other TMI couplers.

Parabolic tapered structure for an ultracompact multimode interference coupler.

A parabolic tapered structure based on general interference has been proposed and studied theoretically with silica waveguides of silicon oxinitride (SiON) core by using a mathematical model based on sinusoidal modes for the reduction of coupling length of a 2x2 multimode interference (MMI) coupler. The coupling behaviors of the proposed structure are compared with those of other MMI structures. It is seen that the beat length for the proposed tapered MMI coupler is approximately half of that of a conventional MMI coupler. The effect of power imbalance on the fabrication tolerance of a 3 dB coupler using the proposed tapered structure is also studied and compared with that of other MMI structures.

Polarization independent thermally tunable erbium-doped fiber amplifier gain equalizer using a cascaded Mach-Zehnder coupler.

A thermally tunable erbium-doped fiber amplifier (EDFA) gain equalizer filter based on compact point symmetric cascaded Mach-Zehnder (CMZ) coupler is presented with its mathematical model and is found to be polarization dependent due to stress anisotropy caused by local heating for thermo-optic phase change from its mathematical analysis. A thermo-optic delay line structure with a stress releasing groove is proposed and designed for the reduction of polarization dependent characteristics of the high index contrast point symmetric delay line structure of the device. It is found from thermal analysis by using an implicit finite difference method that temperature gradients of the proposed structure, which mainly causes the release of stress anisotropy, is approximately nine times more than that of the conventional structure. It is also seen that the EDFA gain equalized spectrum by using the point symmetric CMZ device based on the proposed structure is almost polarization independent.

Education, skills, and working environments of workers in India's rural industry.

Based on a mix of official data and results of a survey conducted in May-June 2000 as part of an ongoing Swedish-Indian-Chinese collaborative study, this paper describes the working conditions of workers engaged in rural industry in India. First, it reports the education and skills of such workers. Educational attainment is presented in terms of both general and technical education. The role played by public institutions in the development of skills is examined. A view of the environment in which these workers work, on the one hand, and the physical/economic conditions of work, on the other, is then developed. Locational and gender disparities are illustrated by rural-urban and male-female comparisons to the extent that the available data permit. Child labor is briefly discussed. The findings are disturbing. The authors offer suggestions for improvement.