All-Optical tunability of metalenses infiltrated with liquid crystals

Metasurfaces have been extensively engineered to produce a wide range of optical phenomena, allowing unprecedented control over the propagation of light. However, they are generally designed as single-purpose devices without a modifiable post-fabrication optical response, which can be a limitation to real-world applications. In this work, we report a nanostructured planar fused silica metalens permeated with a nematic liquid crystal (NLC) and gold nanoparticle solution. The physical properties of embedded NLCs can be manipulated with the application of external stimuli, enabling reconfigurable optical metasurfaces. We report all-optical, dynamic control of the metalens optical response resulting from thermo-plasmonic induced changes of the NLC solution associated with the nematic-isotropic phase transition. A continuous and reversible tuning of the metalens focal length is experimentally demonstrated, with a variation of 80 um (0.16% of the 5 cm nominal focal length) along the optical axis. This is achieved without direct mechanical or electrical manipulation of the device. The reconfigurable properties are compared with corroborating numerical simulations of the focal length shift and exhibit close correspondence.Comment: Main tex

The Role of microRNA in Head and Neck Cancer: Current Knowledge and Perspectives

Head and neck cancer is one of the most commonly diagnosed malignancies worldwide. Patients with advanced disease stages frequently develop recurrences or distant metastasis, which results a five-year survival rates of less than 60% despite considerable advances in multimodality therapy. A better understanding of molecular basis of tumorigenesis is required to improve clinical outcomes and to develop new anti-cancer drugs. microRNAs (miRNAs) are a class of small, non-coding, RNA molecules that modulate gene expression post-transcriptionally. They are important regulator in normal biological process; however miRNAs deregulation has been observed in many different tumors and is involved in tumorigenesis. miRNAs may act as tumor suppressors or as oncogenes. Several studies on head and neck cancer demonstrated how aberrant expression of miRNAs is involved in proliferation, metastasis, chemoresistence, and radioresistance. In addition, miRNAs are excellent biomarker targets because they circulate stable in human body fluids and can be obtained with non-invasive methods. Moreover, miRNAs up and down regulation has been correlated with specific cancer phenotype (poor prognosis, aggressiveness and resistance to treatment), playing a role as prognostic biomarkers. This review summarizes current finding on miRNAs in head and neck cancer and their potential role as target for next drug therapy

Protective effect of pioglitazone, a PPARγ ligand, in a 3 nitropropionic acid model of Huntington's disease

The peroxisome proliferator-activated receptor gamma (PPAR gamma) is a member of the PPAR family. PPAR gamma is the target of insulin-sensitising thiazolidinediones (TZDs), drugs used for the treatment of non-insulin-dependent diabetes. Recently, several studies have shown that PPAR gamma activators can also prevent or attenuate neurodegeneration. The PPAR gamma agonist pioglitazone provides neuroprotection to dopaminergic neurons in lipopolysaccharide (LPS) and MPTP-induced Parkinson's disease experimental models. Here, we investigated whether PPAR gamma activation by pioglitazone protected striatal cells from mitochondrial dysfunction and oxidative stress in a 3 nitropropionic acid (3NP)-induced experimental model of Huntington's disease (HD). Our results suggested that pioglitazone has beneficial effects on mitochondrial dysfunction by interfering with the NF-kappa B signalling pathway, which has been implicated in the pathogenesis of HD. Additionally, we demonstrated that the nuclear translocation of HDAC3 is regulated by 3NP via I kappa B alpha and that treatment with pioglitazone prevented these effects. These results suggested that I kappa B alpha-dependent nuclear translocation is responsible for PPAR gamma inhibition by 3NP and pointed to histone modifications as a novel approach for treating HD. (C) 2011 Elsevier Inc. All rights reserved

A Luminescent, Water-Soluble Ir(III) Complex as a Potential Photosensitizer for Two-Photon Photodynamic Therapy

International audienceThis work reports the study of two-photon induced properties of a highly luminescent cyclometalated Ir(III) complex, [Ir(ppy)2(en)] OOCCH3 (1), ppy = 2-phenylpyridine, en = ethylenediamine. Steady-state and time-resolved fluorescence measurements were performed by exciting 1 at the biologically relevant wavelength of 800 nm, whereas, the generation of singlet oxygen (1O2) was evaluated using 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) as a detection probe. Preliminary in vitro experiments with U87-MG cells were performed, showing the potential of this compound as a two-photon photodynamic therapy (2P-PDT) agent at NIR wavelengths

Third-line trabectedin for a metastatic desmoplastic small round cell tumour treated with multimodal therapy

Desmoplastic small round cell tumour (DSRCT) is a rare and aggressive cancer that usually develops in the peritoneal cavity of young males. Its prognosis is dismal, with current treatment options including the combination of multi-agent chemotherapy, aggressive surgery, radiation therapy, and autologous stem cell transplantation. Hyperthermic intraperitoneal chemotherapy (HIPEC) may also be an option

Cognitive-behavioural phenotype in a group of girls from 1.2 to 12 years old with the Incontinentia Pigmenti syndrome: recommendations for clinical management

Incontinentia Pigmenti (IP, OMIM#308300) is a rare X-linked genomic disorder (about 1,400 cases) that affects the neuroectodermal tissue and Central Nervous System (CNS). The objective of this study was to describe the cognitive-behavioural profile in children in order to plan a clinical intervention to improve their quality of life. A total of 14 girls (age range: from 1 year and 2 months to 12 years and 10 months) with IP and the IKBKG/NEMO gene deletion were submitted to a cognitive assessment including intelligence scales, language and visuo-spatial competence tests, learning ability tests, and a behavioural assessment. Five girls had severe to mild intellectual deficiencies and the remaining nine had a normal neurodevelopment. Four girls were of school age and two of these showed no intellectual disability, but had specific disabilities in calculation and arithmetic reasoning. This is the first description of the cognitive-behavioural profile in relation to developmental age. We stress the importance of an early assessment of learning abilities in individuals with IP without intellectual deficiencies to prevent the onset of any such deficit

Thermoplasmonic Effects in Gain-Assisted Nanoparticle Solutions

We report a detailed characterization of the photoinduced heating observed in gain-assisted solutions of gold nanoparticles (AuNPs). AuNPs, with sizes ranging from 14 to 48 nm and concentration of 2.5 × 10^–10 M, are exposed to different intensity values of a resonant continuous laser (532 nm), used to excite their localized surface plasmon resonance (LSPR), responsible for the photogeneration process. In this way the optimal conditions to achieve the maximum temperature variation with the least laser dosage are obtained. By addition of an organic dye to the solutions, whose emission band overlaps to the LSPR, we found that the contribution to the photothermal efficiency is enhanced if the solutions are excited at 405 nm. This happens in the case of smaller NPs, due to a strong coupling effect between the two subunits, which causes an increase of the extinction cross section of the whole gain-assisted system. On the other hand, for the larger AuNPs, an opposite behavior is found: a loss compensation mechanism, based on a resonant energy transfer process from gain units to plasmonic nanoparticles, limits the increase of the absorption cross section with a consequent lowering of the photothermal efficiency. The presented quantitative analysis of a dispersion of AuNPs results as fundamental for biomedical applications as well as for integrated plasmonic devices based on loss compensation effects, where the impact of undesirable thermal effects cannot be ignored