Isotropic contractive scaling of laser written microstructures in vitrified aerogels

A novel route is presented enabling minimization of feature sizes via laser ablative micro-patterning in highly porous silica aerogel monoliths and subsequent viscous sintering. Vitrification yields isotropically contracted silica solids preserving their original stereometric forms. The contraction depends on aerogel structure and porosity and we demonstrate here the first realization of a 3:1 ratio. Surface relief and void micropatterns inscribed in the monolith also undergo isotropic contraction and feature minimization beyond the spatial resolution of their original recording. Experimental results provide clear evidence that embedded void structures undergo contraction larger than the nominal stereometric scaling. This is a demonstration of a generic principle that enables fundamental physical resolution limits to be surpassed, leading to new avenues in micro- and nano-fabrication technologies

Kallikrein-related peptidase 6 regulates epithelial-to-mesenchymal transition and serves as prognostic biomarker for head and neck squamous cell carcinoma patients

Background: Dysregulated expression of Kallikrein-related peptidase 6 (KLK6) is a common feature for many human malignancies and numerous studies evaluated KLK6 as a promising biomarker for early diagnosis or unfavorable prognosis. However, the expression of KLK6 in carcinomas derived from mucosal epithelia, including head and neck squamous cell carcinoma (HNSCC), and its mode of action has not been addressed so far. Methods: Stable clones of human mucosal tumor cell lines were generated with shRNA-mediated silencing or ectopic overexpression to characterize the impact of KLK6 on tumor relevant processes in vitro. Tissue microarrays with primary HNSCC samples from a retrospective patient cohort (n = 162) were stained by immunohistochemistry and the correlation between KLK6 staining and survival was addressed by univariate Kaplan-Meier and multivariate Cox proportional hazard model analysis. Results: KLK6 expression was detected in head and neck tumor cell lines (FaDu, Cal27 and SCC25), but not in HeLa cervix carcinoma cells. Silencing in FaDu cells and ectopic expression in HeLa cells unraveled an inhibitory function of KLK6 on tumor cell proliferation and mobility. FaDu clones with silenced KLK6 expression displayed molecular features resembling epithelial-to-mesenchymal transition, nuclear β-catenin accumulation and higher resistance against irradiation. Low KLK6 protein expression in primary tumors from oropharyngeal and laryngeal SCC patients was significantly correlated with poor progression-free (p = 0.001) and overall survival (p < 0.0005), and served as an independent risk factor for unfavorable clinical outcome. Conclusions: In summary, detection of low KLK6 expression in primary tumors represents a promising tool to stratify HNSCC patients with high risk for treatment failure. These patients might benefit from restoration of KLK6 expression or pharmacological targeting of signaling pathways implicated in EMT

Special Issue: In memory of Professor Jean Phalippou, one of the pioneers of the Sol-Gel Science and Technology

International audienceJean was a model for numerous PhD students and researcher colleagues because of his scientific and human qualities. He has always been very modest and humble, passionate, and lovely, taking care of his students and helping them accomplish their dreams. Those of us who had the great pleasure to work with Jean will always remember him as an outstanding teacher, a distinguished scholar, but also as a most gentle, humble, and collaborative colleague. We are all in his debt for the enormous contribution he made to the Sol-Gel field of Science and Technology, and he will be deeply missed

Sintering of aerogels for glass synthesis

International audienceSilica glasses can be synthesized by sintering silica aerogels at temperatures ranging from 900 to 1200°C, i.e., close to half the temperatures used for glass melting. The heat treatment can be tailored to obtain either fully densified or porous glass. This paper describes the different steps of the transformation of aerogels into glass along with the textural and microstructural transformations. Different types of information are analyzed: variations in dimensional shrinkage and the apparent density as a function of the densification conditions (temperature, duration of the thermal treatment), the associated structural changes, and the changes in the porous characteristics (macro and meso porosity, average pore radius). The kinetics of dimensional shrinkage help characterize the sintering mechanism. Structural data and porous characteristics allowed us to quantify the transformation of internal aggregates and porosity

Data for Isotropic contractive scaling of laser written microstructures in vitrified aerogels

A novel route is presented enabling minimization of feature sizes via laser ablative micro-patterning in highly porous silica aerogel monoliths and subsequent viscous sintering. Vitrification yields isotropically contracted silica solids preserving their original stereometric forms. The contraction depends on aerogel structure and porosity and we demonstrate here the first realization of a 3:1 ratio. Surface relief and void micropatterns inscribed in the monolith also undergo isotropic contraction and feature minimization beyond the spatial resolution of their original recording. Experimental results provide clear evidence that embedded void structures undergo contraction larger than the nominal stereometric scaling. This is a demonstration of a generic principle that enables fundamental physical resolution limits to be surpassed, leading to new avenues in micro- and nano-fabrication technologies.</span

The kallikrein-related peptidase family: Dysregulation and functions during cancer progression

Cancer is the second leading cause of death with 14 million new cases and 8.2 million cancer-related deaths worldwide in 2012. Despite the progress made in cancer therapies, neoplastic diseases are still a major therapeutic challenge notably because of intra- and inter-malignant tumour heterogeneity and adaptation/escape of malignant cells to/from treatment. New targeted therapies need to be developed to improve our medical arsenal and counter-act cancer progression. Human kallikrein-related peptidases (KLKs) are secreted serine peptidases which are aberrantly expressed in many cancers and have great potential in developing targeted therapies. The potential of KLKs as cancer biomarkers is well established since the demonstration of the association between KLK3/PSA (prostate specific antigen) levels and prostate cancer progression. In addition, a constantly increasing number of in vitro and in vivo studies demonstrate the functional involvement of KLKs in cancer-related processes. These peptidases are now considered key players in the regulation of cancer cell growth, migration, invasion, chemo-resistance, and importantly, in mediating interactions between cancer cells and other cell populations found in the tumour microenvironment to facilitate cancer progression. These functional roles of KLKs in a cancer context further highlight their potential in designing new anti-cancer approaches. In this review, we comprehensively review the biochemical features of KLKs, their functional roles in carcinogenesis, followed by the latest developments and the successful utility of KLK-based therapeutics in counteracting cancer progression