Recovery of plutonium from nitric acid containing oxalate and fluoride by a macroporous bifunctional phosphinic acid resin (MPBPA)

Summary Piroxicam was labeled effectively with ^99mTc due to the presence of electron donating atoms such as sulfur, nitrogen, and oxygen in its structure. The labeling yield was found to be influenced by different factors such as the amount of piroxicam, stannous chloride dihydrate, pH of the reaction mixture, reaction time and reaction temperature. The suitable amount of stannous chloride dihydrate required to produce high labeling yield of ^99mTc-piroxicam was 50 μg, above this quantity (200 μg) a colloidal solution was formed. Another factor which plays a significant role in this labeling reaction is the pH of the reaction medium. The labeling reaction was done only at alkaline pH range from 9-11, because piroxicam was not soluble at acidic or neutral pH. The labeling reaction proceeded well at room temperature and the complex was decomposed by heat. The labeled piroxicam (^99mTc-piroxicam ) showed good localization in inflamed foci and good imaging must be taken at 24-hour post injection, as the ratio of both types of inflammation (sterile and septic) to the background are 10.6 and 8.7, respectively.     

Hadronic cross-sections in \gamma \gamma processes and the next Linear Collider

In this note we address the issue of theoretical estimates of the hadronic cross-sections for processes. We compare the predictions of the mini-jet model with data as well as other models, highlighting the band of uncertainties in the theoretical predictions, as well as those in the final values of the extracted from the data. We find that the rise of with energy shown in the latest data is in tune with the faster rise expected in the eikonal mini-jet models (EMM). We present an estimate of the accuracy with which this cross-section needs to be measured, in order to distinguish between the different theoretical models which try to “explain” the rise of total cross-sections with energy. We find that the precision of measurement required to distinguish the EMM-type models from the proton-like models, for GeV, is , whereas to distinguish between various proton-like models or among the different parametrisations of the EMM, a precision of –9% or –7%, respectively, is required. We also comment briefly on the implications of these predictions for hadronic backgrounds at the next linear collider (NLC) to be run in the mode or mode. Received: 21 October 2000 / Published online: 23 February 2001     

Synthesis,characterization and studies of radiative properties on Eu3+-doped ZnAl2O4

Eu³⁺-doped ZnAl₂O₄ phosphors were successfully synthesized in air atmosphere at 900 °C. The phosphors were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermally stimulated luminescence (TSL) and photoluminescence (PL) techniques. The average particle size of the system as determined from SEM was found to be 100–150 nm (for samples annealed at 900 °C). PL spectra of the doped phosphors showed emission peaks corresponding to Eu³⁺ ions. Lifetime studies revealed Eu³⁺ ions to be in two different sites. The asymmetric ratio (I₆₁₆/I₅₉₂) was observed to be about 3.75. This suggested that Eu³⁺ ion entered the host mainly substituting Al³⁺ site distorting the local environment and is partly located on surface of the phosphors. A prominent glow peak at 430 K was observed in the TSL of γ-irradiated Eu³⁺-doped ZnAl₂O₄ phosphors. Trap parameters for this peak have been determined and the probable mechanism for the glow peak is proposed. CIE chromaticity coordinates for the system were evaluated. It was observed that, the system could be employed as a potential red emitting phosphor. Commercial utility of the phosphor was investigated by comparing it with commercial red phosphor. The PL intensity of the as prepared phosphors was 63% of that of the commercial phosphor. Apart from this, various radiative properties such as the Judd–Ofelt intensity parameters, spontaneous emission probabilities, luminescence branching ratios, radiative lifetimes and quantum efficiency were evaluated for the system.     

Higgs and SUSY searches at future colliders

In this talk, I discuss some aspects of Higgs searches at future colliders, particularly comparing and contrasting the capabilities of LHC and next linear collider (NLC), including the aspects of Higgs searches in supersymmetric theories. I will also discuss how the search and study of sparticles other than the Higgs can be used to give information about the parameters of the minimal supersymmetric Standard Model (MSSM).     

The prediction of tractive performance on soil surfaces

A new approach to the traction prediction equation is described. The proposed equation uses the soil deformation modulus and physical properties of agricultural tyres as parameters. The novel features of this approach include the assumption of a non-linear shear stress distribution and change in the value of soil deformation modulus with the normal stress. A model which suggests a relationship between the contact patch area and the soil deformation modulus is also introduced. The prediction equation was compared with the widely used Wismer and Luth equation and measured data obtained by Wittig. The proposed approach results in an improvement over Wismer and Luth in the prediction of traction and it also involves minimal testing.     

Expression of tropane alkaloids in the hairy root culture of Atropa acuminata substantiated by DART mass spectrometric technique

Agrobacterium rhizogenes-mediated 'hairy root' cultures were established in Atropa acuminata. The chemical profiling of the hairy roots was carried out by a new mass spectrometric technique, direct analysis in real time (DART). The intact hairy roots were directly analyzed by holding them in the gap between the DART ion source and mass spectrometer. Two alkaloids, atropine and scopolamine, were characterized. The structural confirmation of the two alkaloids was made through their accurate molecular formula determinations. This is the first report of establishing hairy roots in A. acuminata as well as application of the DART technique for the chemical profiling of its hairy roots.     

Cascade enantioselective synthesis of γ-aryl-γ-butyrolactones with a delayed stereoselective step

Enantioselective synthesis of γ-aryl-γ-butyrolactones is achieved using (S)-1-phenylethylamine as a chiral auxiliary. The synthesis involves cascade formation-destruction-formation of the chiral centre with a delayed stereoselective step. The actual stereoselective step has been found to be intramolecular nucleophilic attack on a diastereotopic carbocation formed, thereby resulting in the formation of non-racemic γ-aryl-γ-butyrolactones.     

Probing CP-violating Higgs contributions in γγ → f$$ \bar f $$

We discuss the use of fermion polarization for studying neutral Higgs bosons at a photon collider. To this aim we construct polarization asymmetries which can isolate the contribution of a Higgs boson ϕ in γγ → f , f = τ/t, from that of the QED continuum. This can help in getting information on the γγϕ coupling in case ϕ is a CP eigenstate. We also construct CP-violating asymmetries which can probe CP mixing in case ϕ has indeterminate CP. Furthermore, we take the MSSM with CP violation as an example to demonstrate the potential of these asymmetries in a numerical analysis. We find that these asymmetries are sensitive to the presence of a Higgs boson as well as its CP properties over a wide range of MSSM parameters.      

Chemical constituents, antioxidant and antimocrobial activity of essential oil of Pogostemon paniculatus (Willd.)

The essential oil extracted from the leaves of Pogostemon paniculatus (Willd.) Benth. (Lamiaceae), was analysed by gas chromatography-mass spectrometry (GC-MS). Nineteen compounds constituting 85.36% of the total oil were identified in the oil. Patchouli alcohol (30.65%), α-guaiene (10.67%), β-guaiene (9.09%), caryophyllene (8.64%), eicosene (5.27%) were the major constituents present. The essential oil was analysed for antimicrobial activity by disc diffusion assay and minimum inhibition concentration against six bacteria and three fungi. Results showed inhibitory activity against some of the tested microorganisms. The essential oil was also tested for the DPPH free-radical scavenging activity and had an inhibitory concentration (IC(50)) value of 18.5?μg?mL(-1).     

Assessment of DFT based optimized molecular structure-antioxidant efficacy relationship of trimethylgermanium(IV) complexes

Optimized molecular structure-antioxidant efficacy relationship of trimethylgermanium(IV) complexes involving biologically active bulky heterocyclic-O-donor ligands was investigated using density functional theory (DFT). The complexes

where R = -CH₂CH₃[L₍₁₎H],-C₆H₅[L₍₂₎H], p-ClC₆H₄-[L₍₃₎H] were prepared by the reaction of trimethylgermanium chloride with sodium salts of bulky heterocyclic-O-donor ligands in 1:1 M ratio in refluxing dry THF. The complexes were characterized by various spectroscopic techniques namely FTIR, ¹H and ¹³C NMR. The spectral evidences are indicative of a bidentate behaviour of the ligands in these complexes which adopt a pentacoordinated geometry. Computational studies of these complexes have been carried out using B3LYP/6-31G* basis set to obtain molecular geometry, ground state energy and other global reactivity parameters. The most stable geometry having lowest optimized energy was chosen and bond lengths and bond angles were computed. The HOMO-LUMO energies for the complexes have been computed in order to ascertain the energy distribution and reactivity behaviour. These complexes were evaluated for antioxidant activity using FRAP (ferric reducing antioxidant power) assay and demonstrated potential antioxidant activity of distinguishable magnitude.