Preparation of 188Re-labeled hydroxyapatite for radiosynovectomy

Hydroxyapatite (HA), a natural constituent of bone, was synthesized. HA particles were radiolabeled with ¹⁸⁸Re. Radiolabeling efficiency was 95%. In vitro studies showed 5% loss of activity from particles in normal saline over a period of 2 days, whereas a dissociation rate of 9% was observed in human serum albumin.     

Dichotenone-a and -b: two new enones from the marine brown alga Dictyota dichotoma (Hudson) Lamour

Marine brown alga Dictyota dichotoma (Dictyotaceae) collected from Karachi coast of Arabian Sea yielded two new (1 and 2) enones (dolastane-diterpenoids) named: dichotenone-A and -B along with an olide (loliolide, 3) as a new source. Their structures have been characterized with the aid of 2D-NMR spectroscopic techniques.     

Alkaloids and Colon Cancer: Molecular Mechanisms and Therapeutic Implications for Cell Cycle Arrest

Cancer is the second most fatal disease worldwide, with colon cancer being the third most prevalent and fatal form of cancer in several Western countries. The risk of acquisition of resistance to chemotherapy remains a significant hurdle in the management of various types of cancer, especially colon cancer. Therefore, it is essential to develop alternative treatment modalities. Naturally occurring alkaloids have been shown to regulate various mechanistic pathways linked to cell proliferation, cell cycle, and metastasis. This review aims to shed light on the potential of alkaloids as anti-colon-cancer chemotherapy agents that can modulate or arrest the cell cycle. Preclinical investigated alkaloids have shown anti-colon cancer activities and inhibition of cancer cell proliferation via cell cycle arrest at different stages, suggesting that alkaloids may have the potential to act as anticancer molecules.     

Probing quark-distribution amplitudes through generalized parton distributions at large momentum transfer

In the large momentum transfer limit, generalized parton distributions can be calculated through a QCD factorization theorem which involves perturbatively calculable hard kernels and light-cone parton distribution amplitudes of hadrons. We illustrate this through the H(q)(x,xi,t) distribution for the pion and the proton, presenting the hard kernels at leading order. As a result, experimental data on the generalized parton distributions in this regime can be used to determine the functional form of the parton distribution amplitudes which has thus far been quite challenging to obtain. Our result can also be used as a constraint in phenomenological generalized parton distribution parametrizations.     

Ring-A hydroxylated dolastanes from the marine brown alga Dictyota dichotoma (Huds.) Lamour

Marine brown alga Dictyota dichotoma (Dictyotaceae) collected from Karachi coast of Arabian Sea yielded two new dolastane-diterpenoids named: dichototetraol (1) and dichotopentaol (3) along with 2 of the same skeleton as a new source. Their structures have been characterized with the aid of 2D-NMR spectroscopic techniques.     

Mathematical and numerical modeling of melting in metal-ceramic composite beds

Many of the ceramics used in the manufacture of the metal-ceramic composites are available as powders, which has encouraged investigators to develop tool less manufacturing techniques. Innovative processes like combustion synthesis and laser sintering processes offer great potential for specific material combinations. These processes involve heat and mass transfer in porous matrix with melting, solidification and may be chemical reaction. Since the resulting transport is relatively complex, there are few mathematical models available. In the present study, melting and transport of metal is demonstrated for a one-dimensional bed with uniform heat generation and convectively cooled boundaries. The effects of different Bond, Biot and Prandtl numbers are discussed using constant and temperature varying material properties. At low bond number the transport is controlled by capillary forces and temperature and saturation distribution is symmetric about the center of the bed. For Biot number larger than ten the process is internally controlled. Effect of Prandtl number is opposite of that of the Bond number. Use of constant properties overpredicts the process rate by 13%.     

Urease inhibition and anti-leishmanial assay of substituted benzoylguanidines and their copper(II) complexes

A series of N,N',N'-trisubstituted guanidines (1-6) and their copper(II) complexes, [κ(2)(O,N)-C(6)H(5)CONHC(NHC(6)H(4)Cl)NR](2)Cu(ii) (R = iso-propyl (1a), n-butyl (2a), sec-butyl (3a), tert-butyl (4a), benzyl (5a), and para-tolyl (6a)) were synthesized and characterized using elemental analysis, FTIR and NMR spectroscopy. DFT studies were used to assess the location of the protons in the free ligands. However, calculations have shown that, in all cases, hydrogen bonding from either N-H group gives conformations that are very similar in energy. Single crystal XRD studies were used to characterize ligands 1 and 4 and the related complexes 1a and 4a. The structures reveal that these complexes are mononuclear in the solid state and that copper adopts a regular square planar geometry. In both metallic species, the N, N', N'-trisubstituted guanidine ligands chelate the Cu(II) atom using the oxygen and one nitrogen. The synthesized compounds were investigated for urease inhibition using thiourea as a standard drug. Most complexes exhibit a better activity than the respective guanidines and compound 1a was found to be the most active with IC(50) = 9.83 ± 0.07 μM (the IC(50) for thiourea is 21.0 ± 0.1 μM). The species were also screened for their anti-leishmanial activity. However, all of the compounds were devoid of any significant activity.     

Formulation of a freeze-dried kit for 188Re-MAG3 and its quality control

The synthesis of ¹⁸⁸Re-MAG₃ is described using ¹⁸⁸Re, which was obtained from the alumina based ¹⁸⁸W/¹⁸⁸Re generator. Dependence of the radiolabeling yields of ¹⁸⁸Re-MAG₃ on reducing agent concentration, Bz-MAG₃ concentration, pH, temperature and incubation time was examined. In the case of optimum conditions the yield of ¹⁸⁸Re-MAG₃ was 98%. TLC and HPLC techniques were employed to monitor the different species formed. Biodistribution study of ¹⁸⁸Re-MAG₃ was carried out in rats and compared with behavior of ^99mTc-MAG₃.     

Renormalization effects in a field theory of finite nuclei

In case of thep-α system, the Coulomb exchange potential of the resonating group model and of the fish bone optical model are compared with each other. It is seen that the difference between the two approximations arises mainly from the unrealistic shortdistance behaviour of the proton-protone ²/r potential, which has been assumed in both models. In case of the α-¹⁶O system, it is demonstrated that the importance of the Coulomb exchange potential can be very much reduced by an off-shell transformation.