Host-guest interaction of cucurbit[7]uril with para-nitrophenol: A weakly binding inclusion complex

Host-guest interaction between water soluble rigid molecular container cucurbit[7]uril (CB[7]) and a water soluble organic guest para-nitrophenol (PNP) has been investigated using 1H NMR spectroscopy and isothermal titration calorimetry. The stoichiometry, binding constant and other thermodynamic parameters of complexation have been obtained which show the formation of weakly binding 1:1 inclusion complex resulting from enthalpy-entropy compensation. Cyclic voltammetry study of PNP-CB[7] complex in acidic pH reveals a large cathodic shift in the reduction potentials of PNP, indicating either stabilization of PNP or destabilization of the electro-reduced product inside CB[7] cavity

Discussion on a possible neutrino detector located in India

We have identified some important and worthwhile physics opportunitites with a possible neutrino detector located in India. Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other neutrino detectors already in operation.Comment: 9 pages; arXiv copy of published proceedings contributio

Total Syntheses of Malabaricones B and C via a Cross-Metathesis Strategy

The malabaricones A–D belong to the class of diarylnonanoids isolated from the Myristicaceae family of plants. Although malabaricone C displayed various interesting biological activities, its isolation remains tedious due to its close chemical similarity to malabaricones A, B, and D. Therefore, development of an efficient synthesis route has become essential to cater to the need of large amounts of malabaricone C for its pharmacological profiling. So far there is only one report of the synthesis of malabaricone C through a lengthy sequence of reactions. We have developed an efficient and short route for the syntheses of malabaricones B and C, which will also provide a convenient access to all other members of the malabaricone family. Synthesis of an important building block, ω-aryl heptyl bromide, employed in the synthesis was realized by adopting a cross-metathesis reaction as the key step

Surfactant-assisted porphyrin based hierarchical nano/micro assemblies and their efficient photocatalytic behavior

In this report, we have demonstrated the synthesis of surfactant-assisted different morphologies of meso-tetra(4-carboxyphenyl)porphyrin assemblies (spherical to flower shaped). These nano/micro assemblies are well characterized by scanning electron microscopy and X-ray diffraction. The formation of assemblies is driven by noncovalent interactions such as hydrophobic–hydrophobic and aromatic π–π stacking between the molecules. The steady state and time-resolved spectroscopic investigation reveal that different assemblies are formed by virtue of special supramolecular organizations. The photocatalytic activities of different assemblies have been demonstrated with an organic pollutant Rhodamine B dye under the visible light irradiation. Such porphyrin based assemblies could pave the way for designing new optical based materials for the applications in photocatalytic, photovoltaic, and light harvesting system

Graphene induced porphyrin nano-aggregates for efficient electron transfer and photocurrent generation

Significant research attention has been given to graphene–porphyrin hybrid materials for light harvesting. In this report, we demonstrate the influence of graphene surface and aging time on the formation of porphyrin [5-(4-hydroxyphenyl)-10,15,20-triphenyl porphyrin (4-HPTP)] aggregates. The large sp2 conjugated network of reduced graphene oxide (RGO) may facilitate strong π–π stacking interactions that influence the aggregation of 4-HPTP. The morphologies of these assembled structures are characterized by field emission scanning electron microscopy (FE-SEM). Steady state and time resolved spectroscopic studies reveal that the formation of J-type aggregation of 4-HPTP on an RGO surface is higher than on a graphene oxide (GO) surface. In situ growth of porphyrin nanoassemblies on an RGO surface improves the electronic interaction by shortening the interfacial distance between graphene and porphyrin. It is evident that the electron transfer process is enhanced in the presence of RGO upon the photoexcitation of porphyrin nanoassemblies which eventually generate a photocurrent. These graphene decorated porphyrin nanoassemblies are promising materials for the development of new generation optoelectronic devices

miRNA-mediated alteration of sulfatase modifying factor 1 expression using self-assembled branched DNA nanostructures

Sulfatase enzymes catalyze sulfate ester hydrolysis, thus deficiencies of sulfatases lead to the accumulation of biomolecules resulting in several disorders. One of the important sulfatases is estrone sulfatase that converts inactive estrone sulfate to active estradiol. Posttranslational modification of highly conserved cysteine residue leads to unique formylglycine in the active site of sulfatases being critical for its catalytic activity. The essential factor responsible for this modification of sulfatase is Sulfatase-Modifying Factor 1 (SUMF1). The role of estrone sulfatase is well evident in breast cancer progression. However, the function and regulation of SUMF1 in cancer are not studied. In the present study, for the first time, we have assessed the expression of SUMF1 in breast cancer and report the oncogenic behavior upon overexpression of SUMF1. Although increased expression or activity of SUMF1 is anticipated based on its function, the expression of SUMF1 was found to be reduced in breast cancer cells at both mRNA and protein levels. An estrogen receptor (ER) dependent expression of SUMF1 was observed and higher SUMF1 expression is associated with improved breast cancer patient survival in ER-positive cases. However, high SUMF1 expression leads to reduced median survival in ER-negative breast cancer patients. Putative binding sites for miRNAs-106b-5p, 128-3p and 148b-3p were found at 3′-UTR of SUMF1. Since self-assembled branched DNA (bDNA) structures have emerged as a highly efficient strategy for targeting multiple miRNAs simultaneously, we studied the alteration in SUMF1 expression using bDNA nanostructures with a complementary sequence to miRNAs. The findings suggest the involvement of co-regulators and repressors in miRNA-mediated SUMF1 expression in breast cancer cells and reveal the therapeutic potential of SUMF1 in endocrine-related malignancies