Vertically oriented self-assembly of colloidal CdSe/CdZnS quantum wells controlled via hydrophilicity/lipophilicity balance: optical gain of quantum well stacks for amplified spontaneous emission and random lasing.

We propose and demonstrate vertically oriented self-assembly of colloidal quantum wells (CQWs) that allows for stacking CdSe/CdZnS core/shell CQWs in films for the purposes of amplified spontaneous emission (ASE) and random lasing. Here, a monolayer of such CQW stacks is obtained via liquid-air interface self-assembly (LAISA) in a binary subphase by controlling the hydrophilicity/lipophilicity balance (HLB), a critical factor for maintaining the orientation of CQWs during their self-assembly. Ethylene glycol, as a hydrophilic subphase, orients the coalition of these CQWs into self-assembled multi-layers in the vertical direction. Stacking CQWs into large micron-sized areas as a monolayer is facilitated by adjusting HLB with diethylene glycol addition as a more lyophilic subphase during LAISA. ASE was observed from the resulting multi-layered CQW stacks prepared via sequential deposition onto the substrate by applying the Langmuir-Schaefer transfer method. Random lasing was achieved from a single self-assembled monolayer of the vertically oriented CQWs. Here, highly rough surfaces resulting from the non-close packing nature of the CQW stack films cause strongly thickness-dependent behavior. We observed that in general a higher roughness-to-thickness ratio of the CQW stack films (e.g., thinner films that are intrinsically rough enough) leads to random lasing, while it is possible to observe ASE only in thick enough films even if their roughness is relatively higher. These findings indicate that the proposed bottom-up technique can be used to construct thickness-tunable, three-dimensional CQW superstructures for fast, low-cost, and large-area fabrication.

In-situ formation of fluorophore cross-linked micellar thick films and usage as drug delivery material for Propranolol HCl.

Polyethylene glycol monomethyl ether-block-poly(glycidyl methacrylate)-block-poly[2-(diethylamino)ethyl methacrylate] triblock copolymer was synthesized to prepare self-assembled micron sized films via a novel approach named as "phase separated micellar self assembly method". Liquid-air interface self assembly method via slow solvent evaporation was used to obtain micellar films. Cross-linking of polymer films was carried out by diffusion of fluorophore cross-linker into polymer solution from subphase. In-situ micellar formation was triggered via driven forces such as molecular interactions and slow evaporation of solvent. Thiazolo[5,4-d]thiazole based cross-linker fluorophores containing alkali subphases were used to prepare highly fluorescent cross-linked micellar films. Micellar morphologies of the films were characterized with SEM while the cross-sections of fluorophore cross-linked films were observed with TEM analysis to examine diffusion of the dye as nano-sized particles into the polymer film. Convenience and usability of the micellar films as drug delivery material were demonstrated with Propranolol HCl release via UV-Vis spectroscopic studies. Optical properties of the films before and after drug release were determined via photoluminescence spectroscopy to be able to sense the completion of the drug release process. Swelling and shrinkage properties of the films were also determined in different pH values. These highly fluorescent polymer films have great potential as drug delivery materials and biomedical sensing applications.

All-colloidal parity-time-symmetric microfiber lasers balanced between the gain of colloidal quantum wells and the loss of colloidal metal nanoparticles.

Lasers based on semiconductor colloidal quantum wells (CQWs) have attracted wide attention, thanks to their facile solution-processability, low threshold and wide range spectral tunability. Colloidal microlasers based on whispering-gallery-mode (WGM) resonators have already been widely demonstrated. However, due to their microscale size typically supporting multiple modes, they suffer from multimode competition and higher threshold. The ability to control the multiplicity of modes oscillating within colloidal laser resonators and achieving single-mode lasers is of fundamental importance in many photonic applications. Here we show that as a unique, simple and versatile architecture of all-colloidal lasers intrinsically enabled by balanced gain/loss segments, the lasing threshold reduction and spectral purification can be readily achieved in a system of a WGM-supported microfiber cavity by harnessing the notions of parity-time symmetry (PT). In particular, we demonstrate a proof-of-concept PT-symmetric microfiber laser employing CQWs as the colloidal gain medium along with a carefully tuned nanocomposite of Ag nanoparticles (Ag NPs) incorporated into a PMMA matrix altogether and conveniently coated around a coreless microfiber as a rigorously tailored colloidal loss medium to balance the gain. The realization of gain/loss segments in our PT-symmetric all-colloidal arrangement is independent of selected pumping, reducing the complexity of the system and making compact device applications feasible, where control over the pumping is not possible. We observed a reduction in the number of modes, resulting in a reduced threshold and enhanced output power of the PT-symmetric laser. The PT-symmetric CQW-WGM microcavity architecture offers new opportunities towards simple implementation of high-performance optical resonators for colloidal lasers.

Malaria-associated adhesion molecule activation facilitates the destruction of uninfected red blood cells.

Severe malarial anemia (SMA) is the main cause of malaria-associated infant mortality in malaria endemic countries. One major factor that contributes to SMA is the accumulation of uninfected red blood cells (uRBCs) in the spleen. We report the activation of adhesion molecules Lutheran/basal cell adhesion molecule (Lu/BCAM) and CD44 on uRBCs from Plasmodium falciparum in vitro cultures and patients with malaria that mediates adherence to the splenic extracellular matrix (ECM) components laminin-α5 and hyaluronic acid (HA), respectively. This tight ECM-adhesion molecule interaction was associated with elevated intracellular Ca2+ levels, increased shedding of microvesicles, and Lu/BCAM clustering on altered uRBCs. Moreover, we observed that a soluble parasite-derived factor promoted the adhesive phenotype of uRBCs, as the incubation of RBCs with filtered malaria-conditioned medium reproduced the same adhesive effect in malaria culture-derived uRBCs. Eventually, Lu/BCAM and CD44 activation facilitate the adherence to ECM components of the red pulp, resulting in the enhanced splenic retention of uRBCs. Our results suggest a novel adhesion molecule-dependent mechanism that augments malaria-induced anemia.

Inhaler technique in Turkish people with poor English: a case of information discrimination?

OBJECTIVES: (a) To compare metered dose inhaler (MDI) technique in users with poor English and fluent English, (b) to evaluate two interventions: a translated patient information leaflet (PIL) plus support from an translator (PIL + verbal) and a multimedia touch screen system (MTS) using video clips and own-language instruction. METHODS: (a) Inhaler technique was videotaped and key steps rated blind for 105 fluent English-speakers (FE) and 69 Turkish-speakers with poor English (EP). (b) The EP group was randomised to receive information by MTS (n = 34) or PIL + verbal (n = 35). Inhaler technique was videotaped before and after information. MAIN OUTCOME MEASURES: (a) Global inhaler technique; (b) breathing-in time; (c) co-ordination of inspiration and inhaler actuation. RESULTS: Global technique, co-ordination and breath-holding were all significantly worse in MDI users with poor English. Only 17% of that group had adequate technique compared to over half (62%) of FE. The EP group were significantly less likely than the FE group to report ever seeing the practice nurse about their asthma. After information, global technique was rated as improved in 50% of the MTS group compared to 28% of those given a translated PIL. A further six people (17%) in the PIL group improved after subsequent verbal advice in their own language. Both information methods significantly increased inhaler shaking and mouthpiece checking, but co-ordination only improved in a small number of people. CONCLUSIONS: The study suggests that Turkish-speaking MDI users with poor English may be disadvantaged in terms of access to medicines information in the UK. The acceptability of pharmacy-based support services for this, and other specific language groups should be explored. Multimedia offers an alternative to a translator for brief explanations, particularly for first-time users, but improving poor co-ordination requires individualised "hands on" teaching from health professionals.