Bio-functionalization of ligand-free upconverting lanthanide doped nanoparticles for bio-imaging and cell targeting

We report on the functionalization of ligand-free NaGdF(4):Er(3+), Yb(3+) upconverting nanoparticles with heparin and basic fibroblast growth factor (bFGF). These upconverting nanoparticles are used to obtain high-contrast images of HeLa cells. These images reveal that the heparin-bFGF functionalized nanoparticles show specific binding to the cell membrane.     

Testimonial theatre-making: Establishing or dissociating the self.

A group of professional and preprofessional actors (n = 54) from South Africa, (n = 17), the United States (n = 9), and Canada (n = 25) were compared with a healthy and active nonclinical American control group (n = 57) for type of and total traumatic events (TEQ), vividness and extensiveness of fantasy proneness (ICMI), and type and frequency of dissociation (DES-II). All actors had received intensive training in Stanislavski-based acting and participated in theater-making projects that incorporated the creation and performance of testimonial theater. Based on this acting background, we hypothesized that fewer actors would endorse pathological dissociation. This hypothesis was contradicted. Our second hypothesis was found to be correct, that actors endorsed higher fantasy proneness. The last hypothesis was found to be partially correct; fantasy significantly explained some of the variance for dissociation for both the actor and the control groups. There were no significant differences for type and total past traumatic events between the actor and the control groups. Independent sample T tests, multivariate analysis of covariance (with age as a covariate), stepwise linear regression and logistic regression all supported the relationship between fantasy-dissociation in this study. While not minimizing the effect of past trauma, this study revealed that fantasy is significantly associated with the disorienting effects of dissociation. Rather than establishing an integrated self, for some actors, their sense of self remained dissociated. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Luminescence nanothermometry

The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.     

Enhancing Optical Forces on Fluorescent Up‐Converting Nanoparticles by Surface Charge Tailoring

3D remote control of multifunctional fluorescent up‐converting nanoparticles (UCNPs) using optical forces is being required for a great variety of applications including single‐particle spectroscopy, single‐particle intracellular sensing, controlled and selective light‐activated drug delivery and light control at the nanoscale. Most of these potential applications find a serious limitation in the reduced value of optical forces (tens of fN) acting on these nanoparticles, due to their reduced dimensions (typically around 10 nm). In this work, this limitation is faced and it is demonstrated that the magnitude of optical forces acting on UCNPs can be enhanced by more than one order of magnitude by a controlled modification of the particle/medium interface. In particular, substitution of cationic species at the surface by other species with higher mobility could lead to UCNPs trapping with constants comparable to those of spherical metallic nanoparticles.     

Zinc doping effect on the optical bands of cr3 in LiNbO3: Zn, Cr crystals

The optical absorption and luminescence of Cr³⁺ ions in ZnO doped LiNbO₃:Cr³⁺ crystals have been studied. It has been found that ZnO produces the same effect as that observed in MgO co-doped samples: A strong reduction in the Cr³⁺ concentration together with a shift in the ⁴A₂ → ⁴T₁ vibronic transition to lower energy. As in the case of MgO co-doped samples a new Cr³⁺ centre is formed in ZnO co-doped samples.     

Photoluminescence of Ti3+ in P2O5-Na2O-Al2O3 glass

The optical properties (absorption and luminescence) of Ti³⁺ in a P₂O₅ Na₂O-Al₂O₃ glass have been studied in the temperature range 12 to 300 K. A very broad infrared emission band at 860 nm, has been observed for the first time in an inorganic glass, when excitation is performed in the Ti³⁺ absorption band (T_2g → E_g transition in cubic field approximation). The spectroscopic characteristics of this system are compared with those of the Ti³⁺ as a dopant in AL₂O₃ single crystals.