N. Awasthi

ABSTRACT Barren Island of Andaman Sea is the only active vol- cano in the Indian subcontinent. While the volcano has erupted sporadically many times over the last ~70 ka, it is not known when it formed and breached the sea surface. To provide estimates for the timing of these events, we dated two tephra (ash) layers older than 42 ka and generated by this volcanism in a previ- ously studied marine sediment core collected ~32 km southeast of the island using the newly established modern 40 Ar– 39 Ar facility in India. The 40 Ar– 39 Ar pla- teau ages of plagioclase separates from successive tephra layers at 310 and 375 cm are 1.8 ± 0.4 (2 σ ) Ma and 1.5 ± 1.8 (2 σ ) Ma respectively. We interpret the more robust age of 1.8 Ma as the time of crystalliza- tion of plagioclase grains. As this age is very much older than the depositional age of the tephra layer (~61 ka), we infer that it represents the age of older rocks present in the plumbing system of the volcano that were blown out with later pyroclastic eruptions and therefore, sets a strict younger limit to the time of formation of the volcano.

A carbornsed leaf compression is described from the Upper Palaeocene sediments of the Tura Formation near Damalgiri, West Garo Hills, Meghalaya. The leaf form and venation is comparable with Mangifera of Anacardiaceae and named, Eomangiferophyllum damalgiriensis gen. et sp. nov. This was determinC{) only after an ex.tensive study of the anatomy and morphology of several ex.tant species of Mangifera. This

We report compositions of mud, water and gases in mud volcanoes of Andaman forearc.Gases emitted are thermogenic, and derived from subducting marine organic matter.Dehydration of clays is deemed responsible for low salinity of mud waters.The formation temperatures of mud ejecta are estimated to be in the range of 50 °C–120 °C — corresponding to a depth of derivation of 2 to 6 km.Extensive mud volcanism on the Andaman accretionary prism occurs above a complex network of faults and is caused by the convergence of the Indian plate and the Burmese microplate. Mud volcanoes of the Andaman forearc have received little attention in spite of the fact that they are one of the important features of this tectonic setting, located within an ocean basin that has one of the highest sedimentation rates in the world, and that the materials emitted by them present a unique opportunity to study the chemistry of the detachable parts of the subducting slab. In this study we present mineralogical, chemical and isotopic data for argillaceous matter (mud matrix), gases and water emitted by these mud volcanoes and attempt to understand the variations in terms of their sources and processes within the forearc. The mud matrix is composed of smectite–illite–kaolinite–chlorite–plagioclase–quartz–calcite assemblage derived both from sediments and altered oceanic crust and originates from a deep-burial diagenetic environment. The modes of δ13C distributions for methane (>− 42‰), ethane (>− 27‰) and CO2 (<− 3‰) indicate thermogenic origin for these gases, with TOC and N of associated mud suggesting marine organic matter as the source. The water ejected at these mud volcanoes is much fresher (Cl− = 45 to 135 mM) than seawater and its δ18O (− 0.2 to 2.6‰) and δD (− 24 to − 14‰) isotopic compositions fall well below the global meteoric water line. From their trace element contents and stable isotopic compositions we infer that the mud water is a mixture of sediment pore water (ancient seawater) and water released from dehydration of clay minerals. The 87Sr/86Sr of mud water (~ 0.7071) confirms the above inference and points out that altered oceanic crust plays a significant role in controlling the chemistry of water. The formation temperatures of mud ejecta, derived from mineralogical (smectite/illite), chemical (K+/Na+) and isotopic (δD/δ18O) geothermometers, lie in the range of 50 °C–120 °C — which corresponds to a depth zone of 2 to 6 km within the Andaman forearc. Based on all the evidences we conclude that the sampled mud volcano ejecta originate at the plate-boundary décollement zone, from the sediments and altered oceanic crust of the subducting Indian plate.

Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to conventional chemotherapy. The presence of both cellular and stromal fibronectin (FN) and its interaction with integrins is necessary for PDAC progression. We tested the efficacy of endothelial monocyte-activating polypeptide II (EMAP II) to inhibit PDAC progression and its ability to interfere with FN-integrin angiogenesis signaling. In heterotopic PDAC tumors EMAP II caused a significant reduction (>65%) in tumor growth, accompanied by a >50 and 44% decrease in microvessel density and proliferative activity, respectively. EMAP II therapy caused a 62 and 56% reduction in host and tumor cell FN expression. Cultured PDAC cells expressed alphaVbeta3 and alpha5beta1 integrins. In vitro EMAP II had limited antiproliferative effects on ASPC-1, but a pronounced antiproliferative effect on endothellial cells. 3D FN matrices increased ASPC-1 cell proliferation by >50%, and this induction was significantly blocked by alpha3, alpha5, alpha6 and alphaV integrin funtional blocking antibodies, while alpha1, alpha2 and alpha4 antibodies had no effect. EMAP II also inhibited 3D FN-matrix induced ASPC-1 proliferation by >43% at 20 microM. These findings suggest that EMAP II demonstrates significant antitumor activity against PDAC cells, and that this effect may be in part mediated through targeted interference with stromal FN-integrin dependent PDAC cell proliferation.

ABSTRACT Densities and surface tensions were measured for the binary liquid mixtures formed by formamide, N-methylacetamide, di-methylformamide, and di-methylacetamide with acetonitrile at 293.15, 298.15, 303.15, and 313.15 K and atmospheric pressure over the whole concentration range. The Prigogine–Flory–Patterson model, the Ramaswamy and Anbananthan model, the model devised by Glinski, the Sanchez equation, the Goldsack relation, and the Eberhart model were used to predict the associational behaviour of weakly interacting liquids. The measured properties were fitted to the Redlich–Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, the McAllister multibody interaction model was used to correlate the binary properties. These nonassociated and associated models were compared and tested for different systems showing that the associated processes yield fair agreement between theory and experiment compared with nonassociated processes.

... from a sediment core record Neeraj Awasthi & Jyotiranjan S. Ray & Amzad H. Laskar & Alok Kumar & M. Sudhakar & Rajneesh Bhutani & Hetu C. Sheth & Madhusudan G. Yadava Received: 2 June 2010 /Accepted: 5 September 2010 © Springer-Verlag 2010 ...

Metabolism of 1, 1-dichloro-2, 2-bis (4-chlorophenyl) ethylene (DDE), a persistent metabolite of 1, 1, 1-trichloro-2, 2-bis (4-chlorophenyl) ethane (DDT), by an Alcaligenes denitrificans was optimal undernon-shaking'conditions, was accelerated by adding 1 g glucose l-1, and ...

Combining in situ studies of the catalyst activity during single-walled carbon nanotube (SWCNT) growth by mass spectrometry with differential scanning calorimetry and Raman spectroscopy results, the authors expose the favorable features of small catalyst for ...

Catalytic Chemical Vapor deposition (CVD) method is widely used to produce carbon nanotubes. To improve our understanding of the CVD growth mechanism, we focus on the thermodynamics and the phase stability of catalyst Fe-C nanoparticles. Using \textit{ab initio} methods and ...

... & Pub!.) Lakhanpal RN, Prakash U & Awasthi N 1981 Some mOre dicotyledonous woods from the Tertiary of Deomali, Arunachal Pradesh, India. Paiaeobocanisl 27 232-251 Matsuo H 1967 Palaeogene noras of North western Kyushu Part I. The Takashima nora; Ann. Sci. ...

Barren Island, Andaman Sea, is India's only active volcano and is built of lava flows and volcani-clastic deposits of prehistoric through recent ages that are mainly of basalt and basaltic andesite compositions. Historic eruptions occurred during 1787–1832, and it erupted ...