Dimeric lactoglobulin molecules exist in the open conformation at basic pH, whereas they exist in the closed conformation at acidic pH, after undergoing the Tanford transition around neutral pH. Orthorhombic crystals consisting of molecules in the open conformation, grown close to neutral pH, undergo a water-mediated transformation when the relative humidity around the crystals is reduced. The two subunits in the dimer are related by a crystallographic twofold axis in the native crystals while the dimer is asymmetric in the low humidity form. Interestingly, one of the subunits in the dimer in the low humidity form is in an open conformation while the other is in a closed conformation. This is the first observation of such an asymmetric dimer. A hydrogen bond between the side chains of Gln35 and Tyr42 exists and the side chain of Glu89 is substantially buried in the closed subunit of the asymmetric unit, as in other structures with molecules in the closed conformation. However, the closure of the EF loop is not complete; its conformation can be described as half-closed. A comparison of different crystal structures of beta-lactoglobulin indicates that the conformation of the loops in the molecule is substantially influenced by other factors such as crystal packing, the pH, and the composition of the medium, while the change in the conformation of the EF loop follows the Tanford transition. The mutual disposition of the two subunits in the low humidity form is halfway between those in the open and closed structures. The present work further demonstrates that structural changes that occur during partial dehydration could mimic those that occur during the action of proteins.

Bright fluorescent rare-earth-ion-doped upconversion nanomaterials are attractive choices for photonic devices. A remarkable green upconversion emission has been obtained by the sensitizing effect of Yb 3+ in a Yb 3+ /Er 3+ :NaLaMgWO 6 (NLMWO) nanophosphor under near-infrared (NIR) excitation. A citrate sol−gel method was employed to synthesize the nanophosphor samples. The lack of a secondary phase in the X-ray diffraction pattern confirms that the Er 3+ and Yb 3+ ions are incorporated in the ordered double-perovskite structure. Surface analysis and particle evaluation are performed by field-emission scanning electron microscopy and transmission electron microscopy analysis. Upconversion and downconversion emission performances were systematically studied by varying the dopant concentrations. A strong upconversion green emission can be observed with the naked eye, and it resembles the upconversion spectra of Er 3+ -doped phosphors. Remarkably, because of an energy-transfer process, the green upconversion emission can be converted into a strong red emission by codoping with Yb 3+ ions. We observed the color tuning effect from green to red, which can be controlled by varying the Yb 3+ concentration in the codoped phosphors during NIR excitation. A systematic investigation of the upconversion mechanism from Yb 3+ to Er 3+ doubly doped NLMWO nanocrystals is demonstrated. The upconversion mechanism was evaluated only by varying the excitation power of the laser as well. A strong NIR emission at 1.57 μm corresponding to Er 3+ can be significantly enhanced by increasing the codoping concentration of Yb 3+ ions. The energy migration pathway is accurately presented. The Commission internationale de l'ećlairage color coordinates were analyzed for singly and doubly doped nanophosphors. The cytotoxicity of the codoped nanophosphor system was evaluated using WI-38 cell lines. This optimized codoped nanophosphor material is noncytotoxic; thus, it can be useful for in vitro studies in biological studies. On the basis of the obtained results, the NLMWO:Yb 3+ /Er 3+ nanophosphors can be a promising choice for novel upconversion photonic applications.

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The crystal structure of the title compound, C(22)H(25)NO, confirms that the bicyclic ring system adopts the chair-chair conformation. The phenyl rings are equatorially disposed with respect to the bicyclic ring. There is a slight deviation from the chair conformation in the case of the cyclohexane ring.

Synthesis of Cu 2 ZnSnS 4 nanoparticles by solution based solid state reaction process and its application in dye sensitized solar cell as counter electrode AIP Conf.Abstract. Copper tungstate (CuWO 4 ) nanoparticles were prepared by Solid state synthesis. The CuWO 4 nanoparticles were synthesized by reacting 1:1 mole ratio of copper chloride and sodium tungstate. The XRD pattern reveals that the synthesized CuWO 4 has anorthic (triclinic) structure. In addition, the average grain size, lattice parameter values were also calculated using XRD data. The FT-IR analysis confirm the presence of Cu-O and W-O bonds in CuWO 4 nanoparticles. The electrochemical sensing behavior of CuWO 4 nanoparticles towards 4-chlorophenol was investigated using cyclic voltammetry.

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Currently, composite materials have gained momentum in the field of orthopedics and maxillofacial surgery. Among the composite materials, ceramic/polymer possesses significant advantages of high mechanical reliability and excellent biocompatibility for applications in load bearing areas. In this work, polyethylene glycol (PEG)/hydroxyapatite (HAp) nanocomposites of varying weight percentages were synthesized and characterized physical-chemically by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), 31 P nuclear magnetic resonance (NMR), thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and field emission-scanning electron microscopy (FE-SEM) and biologically by antimicrobial and anti-inflammatory assays to evaluate their potential use for biomedical applications. The results indicated that the size and crystallinity of HAp nanoparticles decrease with increase in PEG concentration in the composite. SEM confirmed the presence of HAp nanorod crystals in PEG matrix. The nano PEG-20/HAp demonstrated the highest antifungal and antibacterial activity and favorable inhibition of human cell hemolysis. The designed PEG/HAp nanocomposites constitute promising candidates for biomedical applications.