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Objectives: To study the effects of celiac disease on bone mineral density. Design: Case-control study. Setting: The study was conducted in Department of Anatomy, Sardar Patel Medical College, Bikaner, Rajasthan. Participants: A total of 90 patients, 60 control group healthy normal and 30 celiac disease patients case group were incorporated in study with informed consent. Material and Methods: The bone mineral density was measured in case and control group at calcaneum by peripheral dual X-ray absorptiometry along with body mass index and age. Results: The significant difference was found between the bone mineral density of case and control group (0.87±0.49 & 0.61±0.44: p=0.0001) and 43.33% subjects had osteopenia in case group while only 5% subjects had osteopenia in healthy group. The significant difference of bone mineral density in both groups below the age of 15 years was non existing but between the age group of 16-30 years it was significant (-1.17±0.68 & 0.68±0.21: p=0.001) Conclusion: Celiac disease patients are at higher risk of osteopenia so it is suggested that they should be investigated in early time of diagnosis mainly in the growing years because it affects most at this time. [ABSTRACT FROM AUTHOR]

A new 1,3-diderivative of calix[4]arene appended with hydroxymethyl salicylyl imine is prepared and its ion recognition toward biologically relevant [M.sup.n+] ions is analyzed. The studies have shown that while [H.sub.2]L is selective for [Zn.sup.2+] among a number of cations, the [ZnL] is selective toward phosphate among a number of anions and also toward Asp, Cys and His among the naturally occurring amino acids.

A structurally characterized lower rim 1,3-di{bis(2-picolyl)}amide derivative of calix[4]arene (L) has displayed high selectivity toward [Ag.sup.+] by forming a 1:1 complex, among nine other biologically important metal ions. The in situ prepared silver complex of L has detected Cys ratiometrically among the amino acids to a lowest concentration by releasing L from the complex followed by formation of the cysteine complex of [Ag.sup.+] and the INH logic gate is generated by choosing [Ag.sup.+] and Cys as input.

Several experimental and computational studies are conducted to explain the selective recognition of [Hg.sup.2-] ion exhibited by the amide linked lower rim 1,3-dibenzimidazole derivative of calix[4]arene. The solvent and benzimidazole moieties are shown to play an extremely significant role in the discussed phenomenon.

The torsional barrier of biphenyls bearing a prochiral dimethylsulfonium group at their 3-position could be determined by variable-temperature 1H NMR spectroscopy only after encapsulation into cucurbit[7]- or -[8]uril, which triggered the splitting of the two methyl signals. Confinement of the biphenyl units into the macrocycles amplifies the dissymmetry caused by the various ortho- and ortho′-substituents and represents a new tool that can be used to access atropisomerization barriers of bi(hetero)aryl derivatives. [ABSTRACT FROM AUTHOR]

A calix[4]arene conjugate bearing salicylyl imine having dibenzyl moiety (L) has been synthesized and characterized, and its ability to recognize three most important essential elements of human system, viz., iron, copper, and zinc, has been addressed by colorimetry and fluorescence techniques. L acts as a sensor for Cu2+ and Fe2+ by exhibiting visual color change and for Zn2+ based on fluorescence spectroscopy. L shows a minimum detection limit of 3.96 ± 0.42 and 4.51 ± 0.53 ppm and 45 ± 4 ppb, respectively, toward Fe2+, Cu2+, and Zn2+. The in situ prepared [ZnL] exhibits phosphate sensing among 14 anions studied with a detection limit of 247 ± 25 ppb. The complexes of Zn2+, Cu2+, and Fe2+ of L have been synthesized and characterized by different techniques. The crystalline nature of the zinc and copper complexes and the noncrystalline nature of simple L and its iron complex have been demonstrated by powder XRD. The structures of Cu2+ and Zn2+ complexes have been established by single crystal XRD wherein these were found to be 1:1 monomeric and 2:2 dimeric, respectively, using N2O2 as binding core. The geometries exhibited by the Zn2+ and the Cu2+ complexes were found to be distorted tetrahedral and distorted square planar, respectively. The iron complex of L exists in 1:1 stoichiometry as evident from the mass spectrometry and elemental analysis. [ABSTRACT FROM AUTHOR]

Abstract: A new molecular fluorescent sensor (L) for Cu2+ has been synthesized by derivatizing the lower rim of calix[4]arene with benzothiazole moiety, through amide linkage to result in 1,3-di-derivative. The receptor molecule, L exhibited fluorescence quenching towards Cu2+ among eleven divalent ions, viz., Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Ca2+, Mg2+ and Pb2+, studied. The 1:1 stoichiometry of the complex formed between L and Cu2+ has been demonstrated by electronic absorption and ESI-MS. The role of calix[4]arene for the selective sensing of Cu2+ has been established by comparing the data with that obtained for an appropriate control molecule. The minimum concentration at which L can detect Cu2+ has been found to be 403ppb. The computations carried out at DFT level have provided the coordination and structural features of the Cu2+ complex of L as species of recognition. The Cu2+ complex thus formed recognizes iodide by bringing change in the color, among the 14 anions studied. [ABSTRACT FROM AUTHOR]

A new 1,3-diderivative of calix[4]arene appended with hydroxymethyl salicylyl irnine has been synthesized and its ion recognition toward biologically relevant Mn+ ions studied. The receptor H2L showed selectivity toward Zn2+ by switch-on fluorescence among the 12 metal ions studied with a detection limit of 192 ppb. The interaction of Zn2+ with H2L has been further supported by absorption studies, and the stoichiometiy of the complex formed (1:1) has been established on the basis of absorption and ESI MS. Competitive ion titrations carried Out reveal that the Zn2+ can be detected even tn the presence of other metal ions of bioimportance. The mode of interaction of Zn2+ with conjugate has been established by a fleet of computational calculations carried Out in a cascade manner, either on the ligand or on the complex, wherein the final optimizations were carried out by the density functional theory (DFT) and found that the Zn2+ and Cd2+ indeed bind differently. In situ prepared [ZnL] complex responds to both inorganic phosphate as well as AMP, ADP, and ATP with a minimum detection limit of 426 ppb wherein the Zn2+ from the complex is detached and recomplexed by the added phosphate moiety. It has been possible to build an INHIBIT logic gate for the conjugate using Zn2+ and HPO42- as inputs by monitoring the fluorescence emission band at 444 nm as output. The amino acid senstng abilities of [ZnL] have been explored by fluorescence and absorbance spectroscopy where it showed selectivity toward Cys, Asp, and His through the formation of the Zn2+ complex of these amino acids by chelating through their side chain moieties. Thus, while H2L is selective for Zn2+ among a number of cations, the [ZnL] is selective toward phosphate among a number of anions and also toward Asp, Cys, and His among the naturally occurring amino acids. [ABSTRACT FROM AUTHOR]

Abstract: A (1+1) macrocyclic calix[4]arene based Schiff base derivative has been synthesized and was subjected to complexation with different ions or ionic species, viz., VO2+, , Fe3+, Ni2+, Cu2+ and Zn2+. Both the conjugate and the complexes were characterized using various spectral techniques, viz.; FTIR, 1H, 13C NMR and FAB mass. The complexes have been further characterized by UV–Vis, EPR and magnetic susceptibility, while the iron complex was studied further by Mössbauer spectroscopy. On the basis of all these studies, the VO2+ and complexes were found to be mononuclear, whereas all the other complexes were found to be dinuclear. Based on the studies, the iron complex was found have a distorted octahedral high spin Fe(III) center with an antiferromagnetically coupled dinuclear core in the complex. [Copyright &y& Elsevier]

A structurally characterized lower rim 1,3-di(bis(2-picolyl))amide derivative of calix[4larene (L) exhibits high selectivity toward Ag+ by fonning a 1:1 complex, among nine other biologically important metal ions, viz., Na+, K+, Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, and Zn2+, as studied by fluorescence, absorption, and 1H NMR spectroscopy. The 1:1 complex formed between Land Ag+ has been further proven on the basis of ESI mass spectrometry and has been shown to have an association constant, Ka, of 11117 ± 190 M-1 based on fluorescence data: L acts as a primary ratiometric sensor toward Ag+ by switch-on fluorescence and exhibits a lowest detectable concentration of 450 ppb. DFT computational studies carried out in mimicking the formation of a 11 complex between L and Ag+ resulted in a tetrahedral complex wherein the nitrogens of all four pyridyl moieties present on both arms are being coordinated. Whereas these pyridyls are located farther apart in the crystal structure, appropriate dihedral changes are induced in the arms in the presence of silver ion in order to form a coordination complex. Even the nanostructural features obtained in TEM clearly differentiates L from its Ag+ complex. The in situ prepared silver complex of L detects Cys ratiometrically among the naturally occurring amino acids to a lowest concentration of 514 ppb by releasing L from the complex followed by formation of the cysteine complex of Ag+. These were demonstrated on the basis of emission, absorption, 1HNMR, and ESI mass spectra. The INH logic gate has also been generated by choosing Ag+ and Cys as input and by monitoring the output signal at 445 rim that originates from the excimer emission of L in the presence of Ag+. Thus Lisa potential primary sensor toward Ag+ and is a secondary sensor toward Cys. [ABSTRACT FROM AUTHOR]

Abstract: A highly selective fluorescence switch on sensor, L for detecting Cu2+ has been synthesized by introducing a bis-(2-picolyl)amine moiety at the lower rim of a calix[4]arene platform via amide linkage. Binding properties of L toward ten different biologically relevant Mn+ ions have been studied by fluorescence and absorption spectroscopy in methanol and aqueous methanol. L was found to detect Cu2+ selectively down to a concentration of 196 and 341ppb, respectively, in methanol and 1:1 aqueous methanol even in the presence of other metal ions. The composition of the complex has been found to be 1:1 based on the Job plot and is further confirmed by ESI MS. The role of calix[4]arene platform as well as the pre-organized binding core in the selective recognition of Cu2+ has been demonstrated by studying appropriate reference molecules. The possible modes of binding of L with Cu2+ have been modeled by computational calculations. L and its Cu2+ complex could very well be differentiated based on the nano-structural features observed in SEM and AFM. [Copyright &y& Elsevier]

Abstract: Single crystal XRD structure of the lower rim 1,3-di-amide-derivative of calix[4]arene possessing bis-{N-(2,2′-dipyridylamide)} pendants (L) exhibit two distinct binding cores, viz., N4 and O6. L was found to be selective for Zn2+ by switch-on and for Ni2+ by switch-off fluorescence by forming 1:1 complexes. The binding and the composition of the complex formed have been addressed based on steady state and time-resolved fluorescence spectroscopy in addition to the absorption and ESI MS. As L can detect Zn2+ and Ni2+ to a concentration as low as 142 and 203ppb, respectively, L can be a very sensitive molecular probe for these ions. The coordination details of the metal ion-bound complexes have been addressed based on ab initio calculations showing that the stabilization energies are commensurate with the coordination formed. [Copyright &y& Elsevier]

Amide linked lower rim 1,3-dibenzimidazole derivative of calix[4]arene, L has been shown to be sensitive and selective to Hg2+ in aqueous acetonitrile solution based on fluorescence spectroscopy, and the stoichiometry of the complexed species has been found to be 1:1. The selectivity of L toward Hg2+ has been shown among 11 M2+ ions, viz., Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+, Ca2+, and Mg2+ studied, including those of the mercury group and none of these ions impede the recognition of Hg2+ by L. Role of the solvent on the recognition of Hg2+ has been demonstrated. The role of cali[4]arene platform and the benzimidazole moieties in the recognition of Hg2+ by L has been delineated upon performing such studies with five different molecules of relevance as reference molecular systems. The binding cores formed by the receptor L and the reference compounds have been established based on the single crystal XRD structures, and the preferential metal ion binding cores have been discussed. The binding of Hg2+ with L has been further established based on ¹H and 13C NIMR, ESI MS, absorption, and fluorescence lifetime measurements. Some of these techniques have been used to establish the stoichiometry of the species formed. The complex species formed between L and Hg2+ have been isolated and characterized and found to be 1:1 species even in the isolated complex. Whereas transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM) provided the nanostructural behavior of L, the TEM and SEM demonstrated that the mercury complex has different characteristics when compared to L. The TEM, SEM, and powder XRD studies revealed that whereas L is crystalline, that of the mercury complex is not, perhaps a reason for not being able to obtain single crystals of the complex. Binding characteristics of Hg2+ toward L have been established based on the DFT computational calculations. [ABSTRACT FROM AUTHOR]

Abstract: Interaction of heavy metal ions, viz., Pb2+, Hg2+ and Cd2+ with 1,3-bis(aminoethoxy)-calix[4]arene was studied using emission spectroscopy and the corresponding binding parameters were derived. Based on the changes observed in the fluorescence during titration with these metal ions, two types of species were proposed, viz., one in which the metal ion is bound at the lower rim, the other in which the metal ion interacts through the hydrophobic arene cavity. The extent to which these species were present depends upon the type of the metal ion as well as the number of metal ion equivalents added. The results were compared with unmodified calix[4]arene titration data. Based on these studies, Hg2+ can distinctly be recognized from the other heavy metal ions. [Copyright &y& Elsevier]