Dynamic Behavior of Geogrid-Reinforced Soil

Geosynthetic materials particularly geogrids are widely used as reinforcement and is a proven technology for enhancing the performance of the foundation soil system under monotonic loadings. But the dynamic behavior of the reinforced foundation soil has not been well understood so far, and therefore dynamic loads (square wave pulse) of frequencies 0.2, 0.4 and 1 hertz under an amplitude of displacement of 2mm have been studied by carrying out dynamic plate loading tests on both unreinforced and the reinforced sandy beds. The size of the square plate is 150mm x 150mm x 30mm

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Prospects of Echiniculture in Indi

Cortical AAV-CNTF gene therapy combined with intraspinal mesenchymal precursor cell transplantation promotes functional and morphological outcomes after spinal cord injury in adult rats

Ciliary neurotrophic factor (CNTF) promotes survival and enhances long-distance regeneration of injured axons in parts of the adult CNS. Here we tested whether CNTF gene therapy targeting corticospinal neurons (CSN) in motor-related regions of the cerebral cortex promotes plasticity and regrowth of axons projecting into the female adult F344 rat spinal cord after moderate thoracic (T10) contusion injury (SCI). Cortical neurons were transduced with a bicistronic adeno-associated viral vector (AAV1) expressing a secretory form of CNTF coupled to mCHERRY (AAV-CNTFmCherry) or with control AAV only (AAV-GFP) two weeks prior to SCI. In some animals, viable or nonviable F344 rat mesenchymal precursor cells (rMPCs) were injected into the lesion site two weeks after SCI to modulate the inhibitory environment. Treatment with AAV-CNTFmCherry, as well as with AAV-CNTFmCherry combined with rMPCs, yielded functional improvements over AAV-GFP alone, as assessed by open-field and Ladderwalk analyses. Cyst size was significantly reduced in the AAV-CNTFmCherry plus viable rMPC treatment group. Cortical injections of biotinylated dextran amine (BDA) revealed more BDA-stained axons rostral and alongside cysts in the AAV-CNTFmCherry versus AAV-GFP groups. After AAV-CNTFmCherry treatments, many sprouting mCherry-immunopositive axons were seen rostral to the SCI, and axons were also occasionally found caudal to the injury site. These data suggest that CNTF has the potential to enhance corticospinal repair by transducing parent CNS populations

(±)-Polysiphenol and other Analogues via Symmetrical Intermolecular Dimerizations: a Synthetic, Spectroscopic, Structural and Computational Study

We report an improved total synthesis of 4,5-dibromo-9,10-dihydrophenanthrene-2,3,6,7-tetraol, (±)-polysiphenol, via intermolecular McMurray dimerization of 5-bromovanillin and subsequent intramolecular oxidative coupling as the key steps. The synthetic route is applicable to 4,5-dichloro- and 4,5-difluoro-halologues (as well as a 4,5-dialkyl-analogue). Distinctive AA′BB′ multiplets in their 1H NMR spectra for the dimethylene bridges of the dibromo and dichloro compounds reveal them to be room-temperature stable atropisomers, while for the difluoro compound they present as a singlet. X-ray crystal structure determinations of their tetramethylated synthetic precursors show atropisomeric twist angles of 48°, 46°, and 32°, respectively, with the former representing the largest yet observed in any 4,5-disubstituted-9,10-dihydrophenanthrene. DFT computational studies reveal an unprecedented two-stage atropisomeric interconversion process involving time-independent asynchronous rotations of the dimethylene bridge and the biaryl axis for halologues containing chlorine or bromine, but a more synchronous rotation for the difluoro analogue

Echinoid landings at Mandapam, south-east coast of India with a note on gonadal maturity of two species of sea urchins

The sea urchins, belonging to phylum Echinodermata, are a good source of “roe”, (gonads) and are being consumed by humans since pre-historic times. In many countries of the world, it is a delicacy among the food items and in retail markets in Japan, it is sold at prices as high as US$ 600 kg-1. Among the 800 species of echinoids, 105 species are found along the east coast of India and 30 species are recorded along the coast of Tamil Nadu. There is a paucity of information on the biology and ecology of sea urchins and lack of studies on its edibility and palatability. The sea urchin aquaculture called as echiniculture is picking up in subtropics and temperate areas. Importantly, the tropical marine ecosystem of India, which supports diverse flora and fauna is a suitable environment for echiniculture, and the future research needs to be focused to find out the potential species and developing techniques for their aquaculture. The present investigation analysed the landings of echinoderms in the Gulf of Mannar and Palk Bay along the south-east coast of India and also studied the gonadal maturity of two species of sea urchins viz., Salmacis virgulata and Temnopleurus toreumaticus in order to assess their suitability for echiniculture. S. virgulata and T. toreumaticus formed 70 and 30% respectively of the sea urchins landings at Vedalai and Pampan landing centres. The overall sex ratio of both the species did not deviate significantly from 1:1. In S. virgulata the mean monthly gonad index was highest (9.62±0.46) during September 2014 and for T. toreumaticus, the peak GSI was observed during December 2013. Further studies on captive maturation and breeding are needed to explore the potential of these species for echiniculture

Studies on the Influence of Abiotic Factors in the Gonadal Index of Sea urchin Salmacis virgulata from the Gulf of Mannar, South East Coast of India

The present study was conducted to find out whether the abiotic factors in Gulf of Mannar viz., Sea Surface Temperature (SST) and Day light photoperiod would have an effect on the Gonado somatic index of the dominant sea urchin species Salmacis virgulata. A sampling survey for 20 months was conducted from October-2013 to May-2015 in Vedalai landing centre, along the Gulf of Mannar. The freshly collected sea urchin were brought to Mandapam CMFRI and their Gonado Somatic Index (GSI) was estimated. The remote sensing data of the SST from Gulf of Mannar sourced from ICOADS and the daylight photoperiod were compared with the GSI data for 20 months in order to assess the synchrony among the three parameters. The pearson correlation coefficient of the association among the GSI, SST and Photoperiod revealed that there was no significant correlation (p>0.001). The result of the present study revealed that the Gonado Somatic Index of S. virgulata is independent of abiotic factors, which is in contrast to the temperate sea urchin species, where SST and Photoperiod play a major role in gonadal development

Nitrogen ion beam synthesis of InN in InP (100) at elevated temperature

InN phase is grown in crystalline InP(100) substrates by 50 keV N+ implantation at an elevated temperature of 400 deg C followed by annealing at 525 deg C in N2 ambient. Crystallographic structural and Raman scattering studies are performed for the characterization of grown phases. Temperature- and power-dependent photoluminescence studies show direct band-to-band transition peak ~1.06 eV at temperatures <=150K. Implantations at an elevated temperature with a low ion beam current and subsequent low temperature annealing step are found responsible for the growth of high-quality InN phase.Comment: 11 pages, 4 figures, Journa

Encoding and retrieval in a CA1 microcircuit model of the hippocampus

Recent years have witnessed a dramatic accumulation of knowledge about the morphological, physiological and molecular characteristics, as well as connectivity and synaptic properties of neurons in the mammalian hippocampus. Despite these advances, very little insight has been gained into the computational function of the different neuronal classes; in particular, the role of the various inhibitory interneurons in encoding and retrieval of information remains elusive. Mathematical and computational models of microcircuits play an instrumental role in exploring microcircuit functions and facilitate the dissection of operations performed by diverse inhibitory interneurons. A model of the CA1 microcircuitry is presented using biophysical representations of its major cell types: pyramidal, basket, axo-axonic, bistratified and oriens lacunosummoleculare cells. Computer simulations explore the biophysical mechanisms by which encoding and retrieval of spatio-temporal input patterns are achieved by the CA1 microcircuitry. The model proposes functional roles for the different classes of inhibitory interneurons in the encoding and retrieval cycles

Recall Performance Improvement in a Bio-Inspired Model of the Mammalian Hippocampus

Mammalian hippocampus is involved in short-term formation of declarative memories. We employed a bio-inspired neural model of hippocampal CA1 region consisting of a zoo of excitatory and inhibitory cells. Cells’ firing was timed to a theta oscillation paced by two distinct neuronal populations exhibiting highly regular bursting activity, one tightly coupled to the trough and the other to the peak of theta. To systematically evaluate the model’s recall performance against number of stored patterns, overlaps and ‘active cells per pattern’, its cells were driven by a non-specific excitatory input to their dendrites. This excitatory input to model excitatory cells provided context and timing information for retrieval of previously stored memory patterns. Inhibition to excitatory cells’ dendrites acted as a non-specific global threshold machine that removed spurious activity during recall. Out of the three models tested, ‘model 1’ recall quality was excellent across all conditions. ‘Model 2’ recall was the worst. The number of ‘active cells per pattern’ had a massive effect on network recall quality regardless of how many patterns were stored in it. As ‘active cells per pattern’ decreased, network’s memory capacity increased, interference effects between stored patterns decreased, and recall quality improved. Key finding was that increased firing rate of an inhibitory cell inhibiting a network of excitatory cells has a better success at removing spurious activity at the network level and improving recall quality than increasing the synaptic strength of the same inhibitory cell inhibiting the same network of excitatory cells, while keeping its firing rate fixed