Impact of dust on solar photovoltaic (PV) performance: Research status, challenges and recommendations

The peaking of most oil reserves and impending climate change are critically driving the adoption of solar photovoltaic's (PV) as a sustainable renewable and eco-friendly alternative. Ongoing material research has yet to find a breakthrough in significantly raising the conversion efficiency of commercial PV modules. The installation of PV systems for optimum yield is primarily dictated by its geographic location (latitude and available solar insolation) and installation design (tilt, orientation and altitude) to maximize solar exposure. However, once these parameters have been addressed appropriately, there are other depending factors that arise in determining the system performance (efficiency and output). Dust is the lesser acknowledged factor that significantly influences the performance of the PV installations. This paper provides an appraisal on the current status of research in studying the impact of dust on PV system performance and identifies challenges to further pertinent research. A framework to understand the various factors that govern the settling/assimilation of dust and likely mitigation measures have been discussed in this paper. (C) 2010 Elsevier Ltd. All rights reserved.

Enhanced photodynamic effect of cobalt(III) dipyridophenazine complex on thyrotropin receptor expressing HEK293 cells

Ternary cobalt(III) complexes CoL(B)] (1-3) of a trianionic tetradentate phenolate-based ligand (L) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyridoquinoxaline (dpq in 2) and dipyridophenazine (dppz in 3) are synthesized, characterized from X-ray crystallographic, analytical and spectral techniques, and their utility in photodynamic therapy (PDT) of thyroid diseases caused by TSH receptor dysfunction is probed. The complexes display a visible spectral band within the PDT spectral window at similar to 690 nm. Photodynamic potential was estimated through DNA cleavage activity of the dpq and dppz complexes in UV-A light of 365 nm and red light of 676 nm. The reactions proceed via the hydroxyl radical pathway. The complexes retain their DNA photocleavage activity in red light under anaerobic conditions, a situation normally prevails in hypoxic tumor core. Investigation into the photocytotoxic potential of these complexes showed that the dppz complex 3 is approximately 4-fold more active in the HEK293 cells expressing human thyrotropin receptor (HEK293-hTSHR) than in the parental cell line and has an insignificant effect on an unrelated human cervical carcinoma cell line (HeLa). Photoexcitation of complex 3 in HEK293-hTSHR cells leads to damage hTSHR as evidenced from the decrease in cAMP formation both in absence and presence of hTSH and decrease in the TSHR immunofluorescence with a concomitant cytoplasmic translocation of the membrane protein, cadherin. The involvement of hTSHR is evidenced from the ability of complex 3 to bind to the extracellular domain of hTSHR (hTSHR-ECD) with a K-d value of 81 nM and from the photocleavage of hTSHR-ECD.

A review of hybrid rockets: present status and future potential

This paper discusses the potential of the hybrid rocket engine as a viable and attractive mode of propulsion for both space vehicles and missiles. Research and development work on this engine in other countries is presented and evaluated. The various advantages of a hybrid engine over solid and liquid engines and its problems are highlighted. It has been argued that because of the low technology needed in the development of the hybrid system, it constitutes a cost-and-time-effective propulsion system for several applications in space programmes as well as weapon systems. In support of this conclusion, experience on the developmental studies of a variable thrust 100 kg engine is presented. Some future possibilities for hybrid propulsion systems are cited.

The status and use of tree biomass in a semi-arid village ecosystem

The status of the tree biomass resource was investigated in Ungra, a semi-arid village ecosystem in South India. There were 57 tree species with 12 trees capita−1 and 35 trees ha−1. Multiple benefit yielding local tree species dominated the village ecosystem, while fuel only or single end use trees accounted for a small proportion of trees. The standing tree biomass is adequate to meet the requirement of biomass fuels for cooking only for about two years. Village tree biomass is presently being depleted largely for export to urban areas. Tree regeneration is now characterized by transformation from multiple-use local tree species to a few single-use species. A large potential exists for tree biomass production along field boundaries (bunds), stream banks and roadsides. Biomass estimation equations were developed for 10 species.

Gonadal cell surface receptor for plasma retinol-binding protein A method for its radioassay and studies on its level during spermatogenesis

A specific membrane receptor for plasma retinol-binding protein has been demonstrated in testicular cells. Prealbumin-2 did not show any specific binding to the membrane. The affinity of retinol-binding protein for receptor drastically decreases upon delivery of retinol and the retinol-binding protein does not enter the cell. The mechanism of delivery of retinol to the target cell by plasma retinol-binding protein has been investigated. The process involves two steps: direct binding of retinol-binding protein to the receptor and uptake of retinol by the target cell with a concomitant drastic reduction in the affinity of the retinol-binding protein to the receptor. Probably the second step of the process needs a cytosolic factor, possibly the cellular retinol-binding protein or an enzyme.The binding of retinol-binding protein to the receptor is saturable and reverible. The interaction shows a Kd value of 2.1 · 10−10 M. The specific binding of a retinol-binding protein with great affinity has been employed in the development of a method for radioassay of the receptor. The receptor level of the gonadal cell has been found to vary with the stage of differentiation. The receptor concentrations in 11-week-old birds and adult birds are comparable. Testoterone treatment of 11-week-old birds produced a substantial increase in the receptor concentration over control, while the protein content increased marginally, indicating that, probably, synthesis of the receptor is specifically induced by testoterone during spermatogenesis, and the concentration of receptor is relatively higher before the formation of the acrosome.

Hostility: A prospective study of the genetic and environmental background and associations with cardiovascular risk

Hostility is a multidimensional construct having wide effects on society. In its different forms, hostility is related to a large array of social and health problems, such as criminality, substance abuse, depression, and cardiovascular risks. Identifying and tackling early-life factors that contribute to hostility may have public health significance. Although the variance in hostility is estimated to be 18-50 percent heritable, there are significant gaps in knowledge regarding the molecular genetics of hostility. It is known that a cold and unsupportive home atmosphere in childhood predicts a child s later hostility. However, the long-term effects of care-giving quality on hostility in adulthood and the role of genes in this association are unclear. The present dissertation is part of the ongoing population-based prospective Young Finns study, which commenced in 1980 with 3596 3-18-year-old boys and girls who were followed for 27 years. The specific aims of the dissertation were first to study the antecedents of hostility by looking at 1) the genetic background, 2) the early environmental predictors, and 3) the gene environment interplay behind hostility. As a second aim, the thesis endeavored to examine 4) the association between hostility and cardiovascular risks, and 5) the moderating effect of demographic factors, such as gender and socioeconomic status, on this association. The study found potential gene polymorphisms from chromosomes 7, 14, 17, and 22 suggestively associated with hostility. Of early environmental influences, breastfeeding and early care-giving were found to predict hostility in adulthood. In addition, a serotonin receptor 2A polymorphism rs6313 moderated the effect of early care-giving on later hostile attitudes. Furthermore, hostility was shown to predict cardiovascular risks, such as metabolic syndrome and inflammation. Finally, parental socioeconomic status was found to moderate the association between anger and early atherosclerosis. The new genetic and early environmental antecedents of hostility identified in this research may help in understanding the development of hostility and its health risks, and in planning appropriate prevention. The significance of early influences on this development is stressed. Although the markers studied are individual- and family-related factors, these may be influenced at the societal level by giving accurate information to all individuals concerned and by improving the societal circumstances.

Coated pits,endosome CURLing and intracellular receptor--ligand trafficking

In mediating endocytosis of extracellular macromolecules; the major mechanism in which cells ingest nutrients, degrade hormones and maintain the protein and lipid compositions of their organelle membrane, the cell surface receptors encounter 'coated pits', migrate continuously from one organelle to another, deliver the 'cargo' and often recycle back to the cell surface. This article is an attempt to give an account of the recent advances in our understanding of the molecular events involved in the 'round trip itinerary' of cell surface receptors.

The Madras Triple Helix:Origins and Current Status

Madras triple helix’ was the name assigned by the scientific community in the West, to the molecular model proposed for the fibrous protein collagen, by G N Ramachandran’s group at the University of Madras. As mentioned jocularly in a recent retrospective of this work by Sasisekharan and Yathindra [1], the term was possibly coined due to the difficulty of Western scientists in pronouncing the Indian names of Ramachandran and his associates. The unravelling of the precise nature of collagen structure indeed makes for a fascinating story and as succinctly put by Dickerson [2]: “... to trace the evolution of the structure of collagen is to trace the evolution of fibrous protein crystallography in miniature”. This article is a brief review highlighting the pioneering contributions made by G N Ramachandran in elucidating the correct structure of this important molecule and is a sincere tribute by the author to her mentor, doctoral thesis supervisor and major source of inspiration for embarking on a career in biophysics

Contraceptive vaccines: current status and problems in mass application

Progress in the development of contraceptive vaccines for males and females is reviewed. Based on the criteria which need to be met with, none of the proposed candidate antigens meets the requirements for use as a contraceptive vaccine for human application. One of the major problems is the need for periodic injections to maintain required titre and use of an alternate method until effective titres are obtained. Some of the problems associated with active immunization approach can be overcome by the use of preformed, highly specific, potent antibodies. Some progress has been achieved in this direction by the use of humanized single chain monoclonal antibodies to human chorionic gonadotropin.

Calcium/Calmodulin Dependent Protein Kinase II Bound to NMDA Receptor 2B Subunit Exhibits Increased ATP Affinity and Attenuated Dephosphorylation

Calcium/calmodulin dependent protein kinase II (CaMKII) is implicated to play a key role in learning and memory. NR2B subunit of N-methyl-D-aspartate receptor (NMDAR) is a high affinity binding partner of CaMKII at the postsynaptic membrane. NR2B binds to the T-site of CaMKII and modulates its catalysis. By direct measurement using isothermal titration calorimetry (ITC), we show that NR2B binding causes about 11 fold increase in the affinity of CaMKII for ATP gamma S, an analogue of ATP. ITC data is also consistent with an ordered binding mechanism for CaMKII with ATP binding the catalytic site first followed by peptide substrate. We also show that dephosphorylation of phospho-Thr(286)-alpha-CaMKII is attenuated when NR2B is bound to CaMKII. This favors the persistence of Thr(286) autophosphorylated state of CaMKII in a CaMKII/phosphatase conjugate system in vitro. Overall our data indicate that the NR2B- bound state of CaMKII attains unique biochemical properties which could help in the efficient functioning of the proposed molecular switch supporting synaptic memory.

A novel method for mapping assembled epitopes in batches: Identification of three epitopes at the receptor binding region of human chorionic gonadotropin

Identification of conformation-specific epitopes of hCG beta has been done using a simple batch method, Chemically or enzymatically-modified hCG beta has been prepared in a batch and the effect of modifications on the integrity of different epitope regions has been investigated in a quantitative manner using monoclonal antibodies (MAbs) immobilized on plastic tubes from culture supernatants. Based on the extent of damage done to different regions by different modifications, three conformation-specific epitopes of hCG beta have been identified. The method has been shown to have important advantages over the existing methods on many considerations, Using this approach, these epitopes have been shown to be at/near the receptor-binding region.

Status Survey of the Malabar Pied Hornbill in the Dandeli Region, Northern Western Ghats, India

The Malabar Pied Hornbill, Anthracoceros coronatus, is a near threatened species, endemic to the tropical deciduous forests of central and southern India and Sri Lanka. The Dandeli region in Karnataka (India) is believed to be the last stronghold of this species in the Western Ghats biodiversity hotspot. Being a rapidly developing area with a growing human population, the threats to this species and their habitat are mounting, especially due to a large number of hydroelectric projects and habitat fragmentation caused by paper and plywood industries. This study evaluated the change in population status of the Malabar Pied Hornbill over a 23 year period and defined priorities for the long term conservation and monitoring of hornbills in Dandeli. Encounter rates of hornbills were also analysed in relation to the density and species richness of trees and fruiting trees, basal area, canopy cover and distance from river. Hornbill encounters were not significantly different compared to the earlier study carried out by Reddy in 1988, but were significantly different across the five sites in the current study. Higher numbers of hornbills were encountered closer to the river, but these results were only marginally significant. The mean numbers of hornbills recorded at the two roost sites identified in Dandeli were 26 +/- 4.47 (n=16 counts) and 31.78 +/- 3.53 (n=14 counts) respectively. The study also helped build local awareness about the species, train local Forest Department staff in monitoring hornbills and develop a management plan for its conservation.