Evolution of nocturnal temperature inversions - A numerical study

A series of numerical simulations using a one-dimensional energy balance model suggest that both the depth and the intensity of the nocturnal temperature inversion depend on surface emissivity �g and a ground cooling rate parameter β (which inthe model is a surrogate for the inverse square root of the soil thermal diffusivity), especially under calm conditions. It is found that, after a transient that may last a few hours after nominal sunset, both depth and intensity follow the classical parabolic growth law, but only under calm conditions. If the ground cools faster the transient for the inversion depth is longer and the inversion deeper. If the surface is radiatively darker, the transient is again longer but the inversion depth is lower. The temperature at the top of the inversion is not strongly influenced by �g or β, but, depending on whether the reference is taken at the surface or at screen height, the intensity of the inversion decreases (or increases) with a drop in �g; it also increases with increase in ground cooling rate but with either choice of reference temperature. With wind, the inversion may be deeper during the transient than under calm conditions, but eventually becomes both shallower and weaker, and may disappear altogether at high winds. The effect of wind is found to be negligible whenthe frictionv elocity is less than0.2 ms −1. Comparison with observations shows general qualitative agreement, but also suggests that the highly variable results reported inthe literature onin version parameters may be due to site-dependent surface characteristics whose effects, till now ignored, need explicit attentionin future field observations and models

An anomalous variation in the innervation pattern of the peroneus longus muscle by deep peroneal nerve: a case report

The muscles of the leg are partitioned into three compartments (anterior, lateral and posterior) which have separate innervations. The peroneus longus muscle is included in the lateral compartment and is innervated by the superficial peroneal nerve. We report an unusual finding in the innervation pattern of the peroneus longus muscle on the right side of a 65 year old female cadaver, in which the branches from the deep peroneal nerve were found to innervate the peroneus longus muscle. This finding is of academic interest and clinical significance to surgeons operating on the proximal fibula for nerve decompression, high tibial osteotomy andnerve transfer operations.Key words: Deep peroneal, common peroneal,nerve, peroneus longus, variations

Studies of Phosphazenes: Part II*-Reactions of Hexachlorocyclotriphosphazatriene with N-Methylaniline

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Challenges in materials research for sustainable nuclear energy

Global energy demand is expected to increase steeply, creating an urgent need to evolve a judicious global energy policy, exploiting the potential of all available energy resources, including nuclear energy. With increasing awareness of environmental issues, nuclear energy is expected to play an important role on the energy scenario in the coming decades. The immediate thrust in the science and technology of nuclear materials is to realize a robust reactor technology with associated fuel cycle and ensure the cost competitiveness of nuclear power and to extend the service life of reactors to 100 years. Accordingly, the present-generation materials need to be modified to meet the demands of prolonged exposure to irradiation and extended service life for the reactor. Emerging nuclear systems incorporate features to ensure environmental friendliness, effective waste management, enhanced safety, and proliferation resistance and require development of high-temperature materials and the associated technologies. Fusion, on a longer horizon of about fve decades, also requires the development of a new spectrum of materials. The development of next-generation materials technology is expected to occur in short times and is likely to be further accelerated by strong international collaborations

Development of fuels and structural materials for fast breeder reactors

Fast breeder reactors (FBRs) are destined to play a crucial role in the Indian nuclear power programme in the foreseeable future. FBR technology involves a multi-disciplinary approach to solve the various challenges in the areas of fuel and materials development. Fuels for FBRs have significantly higher concentration of fissile material than in thermal reactors, with a matching increase in burn-up. The design of the fuel is an important aspect which has to be optimised for efficient, economic and safe production of power. FBR components operate under hostile and demanding environment of high neutron flux, liquid sodium coolant and elevated temperatures. Resistance to void swelling, irradiation creep, and irradiation embrittlement are therefore major considerations in the choice of materials for the core components. Structural and steam generator materials should have good resistance to creep, low cycle fatigue, creep-fatigue interaction and sodium corrosion. The development of carbide fuel and structural materials for the Fast Breeder Test Reactor at Kalpakkam was a great technological challenge. At the Indira Gandhi Centre for Atomic Research (IGCAR), advanced research facilities have been established, and extensive studies have been carried out in the areas of fuel and materials development. This has laid the foundation for the design and development of a 500 MWe Prototype Fast Breeder Reactor. Highlights of some of these studies are discussed in this paper in the context of our mission to develop and deploy FBR technology for the energy security of India in the 21st century

Attenuation of camptothecin production and negative relation between hyphal biomass and camptothecin content in endophytic fungal strains isolated from Nothapodytes nimmoniana Grahm (Icacinaceae)

Endophytic fungi, a group of fungi living inside the host plant tissues without causing visible symptoms of disease, are known to occur ubiquitously in plants. Existing in a mutualistic association with their host plants, they have been shown to enhance the plant’s ability to tolerate abiotic and biotic stresses3. In culture, many endophytic species have been shown to produce a number of important secondary metabolites including anticancer,antidiabetic, antifungal and immunosuppressant compounds. Many of these compounds closely mimic those produced by the respective host plants, suggesting that the fungi could in fact potentially serve as an alternative source of plant secondary metabolites. Notwithstanding these findings, to date, there has been no major breakthrough in commercially exploiting the endophytic fungi as a source of important secondary metabolites. Among the reasons attributed is the severe attenuation of production of the secondary metabolite by the fungi in culture. Li et al. showed that successive cultures of an endophytic fungi Pericornia sp. isolated from Torreya grandifolia, resulted in the attenuation of taxol production, though the fungal growth itself was unaffected. Although the reasons for such attenuation are not extensively studied, it is conjectured that it could be due to lack of host stimulus in the culture media

Effect of modified atmosphere packaging on quality of minimally processed fenugreek (Trigonella foenum-graecum L.) microgreens

Fenugreek (Trigonella foenum-graecum L.) microgreens is an underutilized vegetable with limited shelf life having good source of antioxidants, carotenoid as well as vitamins. The study deals with nutritional quality and optimization of a suitable passive modified atmosphere packaging (MAP) for improving the shelf life of fenugreek microgreens in its minimally processed form (MPFM) at 8oC Semipermeable plastic films viz., low density polyethylene, polypropylene, Cryovac PD 961® and stretchable PVC cling film with varying thickness were evaluated as packaging materials to obtain different MAP composition inside MPFM packages. Packaging of MPFM in 40 μm thick polypropylene film resulted in development of in-pack equilibrium MA with 10-14% oxygen and 5-8% carbon dioxide during storage. This in-pack MA maintained ‘fresh-like’ sensory properties, biochemical and nutritional quality in MPFM till 15 days of storage. Significant loss of B vitamins was recorded in all packages during low temperature storage. Packaging in 40 μm thick polypropylene film retained B vitamins significantly better than other semipermeable films. Low temperature storage in modified atmosphere conditions enhanced vitamin E content in MPFM. The outcome of the study will benefit the entrepreneurs and retailers for distant transport and storage of fenugreek microgreens in commercial open chillers maintained in supermarkets in their ready-to-cook form

Patterns of accumulation of camptothecin, an anti-cancer alkaloid in Nothapodytes nimmoniana Graham., in the Western Ghats, India: Implications for identifying high-yielding sources of the alkaloid

Camptothecin, a monoterpene indole alkaloid, is regarded as one of the most promising anticancer drugs of the twenty-first century. Among the various plant sources, the highest yields of the alkaloid are reported from Nothapodytes nimmoniana (Icacinaceae), a small tree distributed in the Indian subcontinent. Because of the enormous demand for the chemical worldwide, there has been an indiscriminate extraction of the trees from many parts of India, especially from the Western Ghats, a mega-diversity forest range along the western coast of India. Recently the tree has been assigned a vulnerable status. In an effort to conserve the remaining populations of the species and to identify high-yielding sources of the alkaloid, attempts are being initiated in chemically profiling the species. As a first step in this direction, we have attempted to establish the general patterns of accumulation of camptothecin in N. nimmoniana across individuals, plant parts, plant size and sex of plants, in the Western Ghats. Individual trees with as high as 100 per cent greater camptothecin content than hitherto reported have been found. The study indicates the potentiality of further screening populations of N. nimmoniana to identify high-yielding sources that can be used for developing in vitro production systems or for establishing high-yielding clonal populations