A note on uniform strong convergence of bivariate density estimates

In this paper we consider a class of estimates of a bivariate density function f based on an independent sample of size n. Under the assumption that f is uniformly continuous, the uniform strong consistency of such estimates was first proved by Nadaraya (1970) for a large class of kernel functions. In this note we show that the assumption of the uniform continuity of f is necessary for this type of convergence.     

High-power, continuous-wave, singly resonant optical parametric oscillator based on MgO:sPPLT

We report a high-power, widely tunable, cw singly resonant optical parametric oscillator (OPO) based on MgO:sPPLT. The OPO is pumped in the green by a cw diode-pumped Nd:YVO(4) laser at 532 nm and can provide continuously tunable output across 848-1430 nm. Using a 30 mm crystal and double-pass pumping, an oscillation threshold of 2.88 W has been obtained, and single-pass idler powers in excess of 1.51 W have been generated over 1104-1430 nm for 6W of pump power at an extraction efficiency of 25.2% and photon conversion efficiency of 56.7%.     

Photoinduced C-Br homolysis of 2-bromobenzophenones and Pschorr ring closure of 2-aroylaryl radicals to fluorenones

A variety of diversely substituted 2-aroylaryl radicals, generated by photoinduced homolysis of 2-bromoarylketones, is shown to undergo Pschorr cyclization to yield fluorenones in moderate to excellent yields. The photochemical results illustrate that the substituents in the two phenyl rings of the 2-bromobenzophenone skeleton exert a dramatic influence on the reactivity of the derived 2-aroylaryl radicals. The disubstitution by methoxy groups in the radical ring renders the aryl sigma-radical highly electrophilic and unreactive for hydrogen abstraction and cyclization. On the other hand, the substituents in the non-radical ring that strongly stabilize the hydrofluorenyl pi-radical, formed subsequent to the attack of the 2-aroylaryl radical on the non-radical ring, promote cyclization to furnish fluorenones in excellent isolated yields.     

Synthesis,characterisation and structural aspects of a new diorganotin(IV) complex with <Emphasis Type="Italic">N</Emphasis>′-(5-bromo-2-hydroxybenzylidene)benzoylhydrazone ligand

A new diorganotin(IV) complex, Me₂Sn[5-Br-(2-OC₆H₄CH=N–N=C(O)Ph)] (1) has been synthesised from dimethyltin(IV) dichloride and a Schiff base derived from 5-bromosalicylaldehyde and benzoyl hydrazide. The complex has been characterised by elemental analysis, and FT-IR and NMR spectroscopies. Molecular structure has been confirmed by single-crystal X-ray diffraction analysis. Complex 1 crystallises in triclinic system, space group P-1 (no. 2) with a=7.562(6), b=9.980(8), c=11.899(8) Å; α=81.08(6)°, β=72.71(5)°, γ=79.64(6)°; Z=2. The ligand N′-(5-bromo-2-hydroxybenzylidene)benzoylhydrazone (H₂L) coordinates to the metal centre in enolate form via the phenolic O, imino N and enolic O atoms. The central tin atom is in distorted trigonal bipyramidal geometry with two oxygen atoms of the ligand in axial positions, while the imino nitrogen atom of the ligand and two methyl groups on tin occupy the equatorial sites.     

Integrated magnetic bionanocomposites through nanoparticle-mediated assembly of ferritin

Magnetic (FePt) and nonmagnetic (Au) nanoparticles were used to assemble ferritin into near-monodisperse bionanocomposites featuring regular interparticle spacing. The FePt/ferritin assemblies are integrated magnetic materials with ferritin providing added magnetic volume fraction to the magnetic nanocomposite. These assemblies differ from either of their constituent particles in terms of blocking temperature (TB), net magnetic moment, coercivity, and remnance.     

Novel photochromism of differently-linked bis-benzopyrans

The unique photochromic bis-chromene 5 incorporates the structural attributes of both 3 and 4 . UV-vis irradiation of 5 leads to a dark brown colour, which is formed by mixing the purple and red colours observed for the photolysates of 3 and 4 , respectively.     

Photoinduced electron transfer reaction in room temperature ionic liquids: a combined laser flash photolysis and fluorescence study

A detailed study of the photoinduced electron transfer (PET) reaction between pyrene and N,N-dimethylaniline has been made in four different room temperature ionic liquids (ILs) using steady state and time-resolved fluorescence and laser flash photolysis techniques. Unlike that in the conventional media, no exciplex emission for this well-known system could be observed in ILs. The rate constants for the PET induced quenching of the fluorescent state of pyrene, which lie between 6.9 and 37 x 107 M-1 s-1 depending on the viscosity, are found to be 2-4 times higher than the diffusion-controlled rates in ILs. The primary photoproducts of the PET process have been characterized by transient absorption spectroscopy, and the yields of the solvent-separated PET products have been determined. Even in the least viscous IL, [emim][Tf2N], the yield of the solvent-separated radical ion is estimated to be only 0.015 +/- 0.005. In more viscous ILs such as [bmim][PF6], the yield is found to be so low that absorption due to these species could not be observed. The rate constant for the escape of the ionic products from the geminate ion pair in ILs has been estimated to be nearly 2-3 orders of magnitude lower than the back electron transfer rate. However, the small fraction of the PET products, which manage to escape geminate recombination, have been found to survive much longer compared to those in less viscous conventional solvents.     

Steric and electronic effects in capsule-confined green fluorescent protein chromophores

The turn-on of emission in fluorescent protein chromophores sequestered in an "octaacid" capsule is controlled by stereoelectronic effects described by a linear free energy relationship. The stereochemical effects are governed by both the positions and volumes of the aryl substituents, while the electronic effects, including ortho effects, can be treated with Hammett σ parameters. The use of substituent volumes rather than A values reflects packing of the molecule within the confines of the capsule.     

Synthesis and characterization of a cell-permeable near-infrared fluorescent deoxyglucose analogue for cancer cell imaging

We report the synthesis and characterization of a novel NIR fluorescent deoxyglucose analogue, CyNE 2-DG. Experiments in different cell lines showed a preferential uptake of CyNE 2-DG in cancer cells and its effective competition with unlabeled d-glucose. Cell imaging experiments demonstrated the superior cell-permeability of CyNE 2-DG over the NIR standard IRDye 800CW 2-DG, and validated its application for cancer cell imaging in the NIR region.