Paleomagnetic results are reported for a swarm of diabase dikes from the northeastern Gander Zone of the Newfoundland Appalachians. Sixty-eight cores were collected from 19 dikes cutting the various granites and migmatites from the Bonavista Bay area of Newfoundland. From the earlier structural and Rb/Sr age data available, one can infer an age for the dike swarm of between 400 and 330 Ma. Paleomagnetic studies including alternating field and thermal demagnetizations reveal that the swarm can be divided into two groups: group 1 has a characteristic magnetization of D = 296.6°, I = 82.2° with α 95 = 5.8° for N = 14 dikes with the corresponding pole position at 53.9°N, 77.4°W (δp, δm = 11.0°, 11.3°; group 2 has a characteristic magnetization of D = 157.6°, I = 53.9° with α 95 = 9.0° for N = 5 dikes with the corresponding pole position at 3.9°S, 35.5°W (δp, δm = 8.8°, 12.6°). One dike's magnetization was found to be reversed relative to the other group 2 dikes. Various magnetic experiments (low- and high-field hysteresis, Curie temperatures, susceptibility variation with temperature, coercivity of remanence, Lowrie–Fuller test) conducted to study the bulk magnetic and remanent magnetic properties of the dike material suggest that their behavior is consistent with multidomain pure magnetite being the dominant magnetic mineral. The group 1 pole position lies close to Newfoundland and is similar to other poles of equivalent age for intrusives from New Brunswick and Newfoundland. Rock units from the southeastern margin of the Iapetus Ocean thus seem to be yielding consistent "high-latitude" poles, a factor that needs to be taken into account in any discussion of the tectonic evolution of the area.

Background: Peptides and proteins have both sequence-specific (contiguous) and conformation-specific (discontiguous) epitopes. Sequence-specific epitopes are delineated by peptide approach and other robust methods like competition assays, gene expression assays, synthetic peptide library based assays etc. Available methods for delineation of conformation-specific epitopes are cumbersome (X-ray crystallography etc.), time-consuming and require costly sophisticated equipments. Hence, there is a need to develop a simple method for identification and mapping of conformation-specific epitopes.Method: In the single-step solid phase radioimmunoassay (SS-SPRIA), an immunochemical bridge of 'mouse IgG-anti-mouse IgG' was prepared in the polypropylene wells followed by adsorption with hCG specific monoclonal antibody (MAb) G(1)G(10).1. The extent of competitive inhibition in binding ability of (125)IhCG-beta with chemically or enzymatically modified hCG-beta to immobilized MAb G(1)G(10).1 in comparison to hCG-beta standards was utilized to identify the epitopic amino acid involved in epitope-paratope interaction.Results: Data clearly suggest that the epitope under investigation consisted of Arg (94, 95) and Asp (99) at the core region with a Lys (104) and a His (106) in the proximity and absence of chymotrypsin susceptible Phe or Tyr in this region.Conclusion: The data of SS-SPRIA revealed the 93-100 loop of amino acid sequence, as the core region of conformation-specific epitope of hCG-beta at or near the receptor-binding region. Hence, SS-SPRIA seems to be a simple method for identification and mapping of conformation-specific epitopes. (c) 2006 Elsevier B.V. All rights reserved.

Uranium antimonate (USb) has been prepared and characterized by various analytical techniques such as TG-DTA, EDXRF, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and FT-IR spectroscopy. The precipitation reaction of potassium pyroantimonate (KSb(OH)6) with uranyl nitrate results in the formation of amorphous USb with U/Sb mole ratio of 0.35, which crystallises at temperature above 900°C, leading to the formation of USb3O10. The amorphous form and heat treated uranium antimonate exhibits ion exchange with some fission products like 137Cs+, 90Sr2+ and 154Eu3+ due to the presence of surface hydroxyl groups and the distribution coefficient (Kd, mL/g) decreases with heat treatment. Thermal analysis of USb indicated the loss of surface hydroxyl groups due to the condensation reaction is responsible for the decrease in Kd values after heat treatment. Based on the analytical and sorption data on uranium antimonate a molecular formula of HUO2Sb3O4(OH)10·4.7 H2O has been arrived.

Dicyclohexano-18-crown-6 (DCH18C6) has been intercalated in bentonite and the product, Ben-Crown, characterized by microelemental analysis, TG-DTA analysis, X-ray diffraction and IR spectroscopy. The permanent negative charge present in the bentonite layer has been exploited for more efficient extraction of cesium and strontium by Ben-Crown at nitric acid concentrations (<1.0 M) that gave only a meagre extraction when either DCH18C6 or bentonite alone were employed. The extraction of cesium and strontium has been investigated as a function of time, temperature, and the concentrations of nitric acid, metal ion and sodium nitrate. An unusual extraction phenomenon was observed at low concentrations of nitric acid (<1.0 M) in the absence of any organophilic agents. Rapid extraction of the metal ion was followed by the establishment of an equilibrium, which occurred after 150 min. Distribution coefficients (K-d) of 599 and 1007 ml g(-1) were obtained, respectively, for the extraction of cesium and strontium from 0.1 M nitric acid by Ben-Crown; K-d decreased with an increase in the temperature or in the concentrations of nitric acid and sodium nitrate. The extraction data were fitted by the Langmuir adsorption model and the apparent experimental exchange capacity obtained by linear regression analysis was in good agreement with the amount of crown ether (0.22 mmol g(-1)) intercalated in bentonite. The enthalpy change (Delta H degrees) for the extraction of cesium and strontium was found to be exothermic.

Polyantimonic acid was precipitated in the pores of Amberlite XAD-7 (PAA–XAD) and studied for the ion exchange of strontium as a function of various parameters, such as time, strontium ion concentration and temperature. Nearly 30% of the Sb2O5 was impregnated into XAD-7 exhibiting an experimental capacity of 23mg/g of strontium. Distribution coefficient of strontium on PAA–XAD was found to be 6069mL/g at 0.1mol/L nitric acid and it decreased with increase in the concentration of nitric acid. Rapid uptake in the initial stages of equilibration was observed followed by sluggish rate of exchange and the ion exchange reaction was found to follow the second order rate equation. The rate constant and energy of activation for such reaction were found to be 8.4 × 10−3Lmg-1min-1 at 300K and 79kJ/mol, respectively. The data obtained in this study were fitted into Langmuir adsorption model and Langmuir constants obtained at various temperatures were utilized for estimating the enthalpy change (ΔHo) accompanied by the ion exchange. The performance of the sorbent under dynamic conditions was evaluated by following a breakthrough curve using simulated waste solutions.

The applicability of zirconium phosphate-ammonium molybdophosphate (ZrP-AMP) for the efficient removal of cesium from aqueous acidic solutions by adsorption has been investigated. The adsorption data analysis was carried out using the Freundlich, Dubinin-Raduskevich (D-R) and Langmuir isotherms for the uptake of Cs in the initial concentration range of 3.75 . 10 -5 -7.52 . 10 -3 mol . dm -3 on the ZrP-AMP exchanger from nitric acid medium. The mean free energy ( E ) values for the adsorption of Cs were obtained from the D-R isotherm. Equilibrium adsorption values at different temperatures have been utilized to evaluate the change in enthalpy, entropy and free energy (Δ H °, Δ S °, Δ G °). The adsorption of cesium on the ZrP-AMP exchanger was found to be endothermic.

Summary Ion exchange properties of cesium, strontium and europium on uranium antimonate (USb) from nitric acid medium was studied. The distribution coefficient (Kd) of 1046 mL/g for cesium, 2464 mL/g for strontium and ∼105 mL/g for europium were obtained for sorption from 0.01 M nitric acid and Kd decreased with increase in the concentration of nitric acid. Rapid sorption of metal ions in the initial stages of equilibration followed by the establishment of equilibrium after 24 hours. Cesium sorption on USb follows ideal ion exchange while strontium and europium do not. From Langmuir adsorption model for the sorption of these ions on USb, the apparent sorption capacity was found to be of 6.9 mg/g for cesium, 19.1 mg/g for strontium and 37.2 mg/g for europium at 300 K. The enthalpy change (ΔH°) accompanied by the sorption was determined by the temperature variation method. The performance of the sorbent under dynamic conditions was assessed by following a breakthrough (BT) curve up to C/C0=1. Extraction chromatography of individual ions from the mixture using USb was also reported in this paper.

Ion exchange of cerium on uranium antimonate (USb) from nitric acid medium was studied. The distribution coefficient of ~19,000 mL/g was obtained for ion exchange of cerium in 0.1 M nitric acid and it decreased with increase in the concentration of nitric acid. Rapid ion exchange of cerium in the initial stages of equilibration followed by the establishment of equilibrium occurs after one hour. Ion exchange data were fitted into both Langmuir and Freundlich adsorption models using non-linear regression. The enthalpy change accompanied by ion exchange of cerium was determined by the temperature variation method. The performance of the ion exchanger under dynamic condition was assessed by following a breakthrough (BT) curve and the BT curve was fitted using Thomas equation.

A new inorganic ion exchanger, zirconium phosphate-ammonium molybdophosphate (ZrP-AMP) has been prepared in granular form, suitable for column operation. The results obtained from TG-DTA, IR and X-ray diffraction studies for this exchanger are presented. The k(d) values for different metal ions were determined and the affinity order was found to be Cs>>Rb>Zr>Ce>rare earths. pH titration curve, breakthrough capacities for cesium in different types of simulated nuclear wastes and elution of cesium from ZrP-AMP column have been studied. Conditions for separation and isolation of cesium from other fission products in simulated waste solutions have been established. The exchanger was found to be stable to ay-radiation dose of 10(8) rads.

Uranium antimonate (USb) has been prepared by the precipitation reaction between uranyl nitrate and potassium pyroantimonate and it has been characterized by X-ray diffraction (XRD), thermal analysis, energy disperse X-ray florescence, and pH titration. Ion exchange of europium on USb as a function of time, temperature, concentration of nitric acid and europium has been studied. The distribution coefficient of europium on USb was found to decrease from ∼105mlg−1 at 0.05M nitric acid to 22mlg−1 at 2M nitric acid. Uptake of europium was fitt to a particle diffusion equation and the diffusion coefficient (Di) was calculated from the slope of Bt–t plots. The energy (Ea) and entropy (ΔS∗) of activation for the sorption of europium were found to be 17kJmol−1 and −67.9Jmol−1K−1, respectively. Sorption data obtained at various concentrations of europium were fitted into a Langmuir adsorption isotherm and the enthalpy change accompanied by the sorption of europium was determined by the temperature variation method.

tium on vermiculite and ZrMV increased with increase in pH and lowering concentration of Sr 2+ . The rate of uptake of strontium by ZrMV was found to be much faster than that for vermiculite. The distribution coefficient of strontium on ZrMV is of the order of 10 4 mL/g at pH 3, and the amount of strontium sorbed on ZrMV was always found to be much higher than that on the parent clay. The sorption data were fitted to Langmuir adsorption model for obtaining the sorption capacity of the sorbent. Increase of temperature increases the distribution coefficient of strontium on both ZrMV and vermiculite. Distribution of strontium on ZrMV was also determined from the groundwater samples obtained from the waste disposal site at Kalpakkam.

The outer membrane protein OmpC, a trimer made of 16 stranded β-barrel monomers, is a major cell surface antigen from the human pathogen Salmonella typhi. The relative stability of the epitopes recognising a Salmonella specific MAb (referred as MPN5) and an Enterobacteria specific MAb (referred as P7D8) and the role of the trimeric organisation has been probed using gel electrophoresis and monoclonal antibodies. The assembly of the trimer and the stability of the β-barrel are found to be important for epitope presentation. The Salmonella specific conformational epitope is found to be more stable than the Enterobacteria specific one. The important residues of the Salmonella specific (Asp 25 of loop 1, Asp 340 of loop 8, Lys 334 of loop 8, and Tyr 210 of loop 5) and the Enterobacteria specific (Asp 25 of loop 1, Tyr 210 of loop 5, and Lys 152 of loop 4) conformational epitope have been identified using monoclonal antibodies, chemical modification, and solid phase binding methods.

A composite mixture of zirconium molybdate and zirconium tungstate was prepared and studied for the sorption of cesium and strontium as a function of nitric acid, metal ion concentration, time and temperature. The distribution coefficient (K d ) of 7000 ml/g (~90% sorption) and 70 ml/g (~20% sorption) was obtained for the sorption of cesium and strontium in 0.1M nitric acid, respectively. Experimental sorption capacity, b for cesium was found to be 50 mg/g from 0.1M HNO 3 and 30 mg/g for strontium from 0.001M nitric acid. The sorption of strontium on the sorbent was accompanied by the absorption of heat but the sorption of Cs + results in the liberation of heat. Column studies were conducted by following a breakthrough (BT) curve of cesium and strontium up to C/C 0 =1 and the results are reported.

The applicability of ammonium molybdophosphate-alumina (AMP-Al2O3) for the efficient removal of Cs from aqueous solution by adsorption has been investigated. The kinetics of adsorption of cesium ions has been studied by using radioanalytical procedure over a concentration range of 10−4−10−2 mol.dm−3 and in the temperature range of 303–318 K. The results showed that the uptake follows the first order rate law with respect to cesium concentration and obeys Langmuir and modified Freundlich adsorption isotherm in the concentration range studied. Equilibrium adsorption values at different temperatures have been utilised to evaluate change in standard thermodynamic parameters (ΔH0, ΔG0 and ΔS0). From the thermodynamic parameters it is found that the process is exothermic in nature.

The applicability of zirconium molybdoarsenate (ZrMAs) for efficient removal of Cs from aqueous solution by adsorption has been investigated. The kinetics of adsorption of caesium ions has been studied by using radioanalytical procedure over a concentration range (10−4−10−2 mol dm−3) and in the temperature range (303–318 K). The results showed that the uptake follows the first order rate law with respect to caesium concentration and obeys Langmuir and Modified Freundlich adsorption isotherms in the concentration studied. The effect of temperature on adsorption equilibrium has been studied and the thermodynamic quantities (ΔHo, ΔGo and ΔSo) has been evaluated. They showed that the process is exothermic in nature.

A study of 140 days duration was performed to examine if human male volunteers (n = 5) respond to ovine follicle stimulating hormone (oFSH) immunization (administered adsorbed on Alugel on days 1, 20, 40 and 70) by producing antibodies capable of both binding and neutralizing bioactivity of human FSH. The kinetics of antibody production for both the immunogen (oFSH) and the cross-reactive antigen (hFSH) were essentially similar. The volunteers responded only to the first two immunizations. The boosters given on days 40 and 70 were ineffective, probably because of the presence of substantial amounts of circulating antibody to oFSH. Of the antibodies generated to oFSH, 25-45% bound hFSH with a mean binding affinity of 0.65 x 10(9) +/- 0.53 M(-1). The binding capacities at the time of high (30-80 days of immunization) and low (>110 days) titres were 346 +/- 185 and 10.5 +/- 5.8 ng hFSH/ml respectively. During the period of high titre, free serum FSH (value in normal males 1-5 ng/ml) was not monitorable. A 50 microl aliquot of the antiserum obtained from different volunteers between days 30 and 80 and on day 140 blocked binding of (125)I-labelled hFSH to its receptor by 82 +/- 9.7 and 53 +/- 12.2% respectively. The antibody produced was specific for FSH, and no significant change in the values of related glycoprotein hormones (luteinizing hormone/testosterone and thyroid stimulating hormone/thyroxine) were recorded. Seminal plasma transferrin, a marker of Sertoli cell as well as of seminiferous tubular function, showed marked reduction (30-90%) following immunization with oFSH. Considering that endogenous FSH remained neutralized for approximately one sperm cycle only (65 days), the reduction in sperm counts (30-74%) exhibited by some volunteers is encouraging. Immunization with oFSH did not result in any significant changes in haematology, serum biochemistry or hormonal profiles. There was no production of antibodies capable of interacting with non-specific tissues. It is concluded that it should be possible to obtain a sustained long-term blockade of endogenous FSH action in men by using oFSH as an immunogen. This is a prerequisite for obtaining significant reduction in the quality and quantity of spermatozoa produced, thus leading to infertility.

A single-step solid-phase RIA (SS-SPRIA) developed in our laboratory using hybridoma culture supernatants has been utilised for the quantitation of epitope-paratope interactions. Using SS-SPRIA as a quantitative tool for the assessment of epitope stability, it was found that several assembled epitopes of human chorionic gonadotropin (hCG) are differentially stable to proteolysis and chemical modification. Based on these observations an approach has been developed for identifying the amino acid residues constituting an epitopic region. This approach has now been used to map an assembled epitope at/near the receptor binding region of the hormone. The mapped site forms a part of the seat belt region and the cystine knot region (C34-C38-C88-C90-H106). The carboxy terminal region of the alpha-subunit forms a part of the epitope indicating its proximity to the receptor binding region. These results are in agreement with the reported receptor binding region identified through other approaches and the X-ray crystal structure of hCG.

Potential alpha energy concentration (PAEC) due to radon and its progenies has been measured in dwellings of three different cities in India; namely Allahabad (in north central region), Vishakapatnam (in south eastern region) and Shillong (in north eastern region), The measurements were carried out by a passive, time-integrated method, using LR 115 (Type II) detector in bare mode. The geometric mean of potential alpha energy concentration in dwellings of Allahabad, Vishakapatnam and Shillong has been estimated to 10.0 mWL, 3.9 mWL and 11.3 mWL, respectively. The results obtained for dwellings in these three cities are discussed in the light of exposure limits set by the International Commission on Radiological Protection (ICRP).

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.