Static High Voltage Actuation of Piezoelectric AlN and AlScN Based Scanning Micromirrors.

Piezoelectric micromirrors with aluminum nitride (AlN) and aluminum scandium nitride (Al0.68Sc0.32N) are presented and compared regarding their static deflection. Two chip designs with 2 × 3 mm2 (Design 1) and 4 × 6 mm2 (Design 2) footprint with 600 nm AlN or 2000 nm Al0.68Sc0.32N as piezoelectric transducer material are investigated. The chip with Design 1 and Al0.68Sc0.32N has a resonance frequency of 1.8 kHz and a static scan angle of 38.4° at 400 V DC was measured. Design 2 has its resonance at 2.1 kHz. The maximum static scan angle is 55.6° at 220 V DC, which is the maximum deflection measurable with the experimental setup. The static deflection per electric field is increased by a factor of 10, due to the optimization of the design and the research and development of high-performance piezoelectric transducer materials with large piezoelectric coefficient and high electrical breakthrough voltage.

2D Scanning Micromirror with Large Scan Angle and Monolithically Integrated Angle Sensors Based on Piezoelectric Thin Film Aluminum Nitride.

A 2D scanning micromirror with piezoelectric thin film aluminum nitride (AlN), separately used as actuator and sensor material, is presented. For endoscopic applications, such as fluorescence microscopy, the devices have a mirror plate diameter of 0.7 mm with a 4 mm2 chip footprint. After an initial design optimization procedure, two micromirror designs were realized. Different spring parameters for x- and y-tilt were chosen to generate spiral (Design 1) or Lissajous (Design 2) scan patterns. An additional layout, with integrated tilt angle sensors, was introduced (Design 1-S) to enable a closed-loop control. The micromirror devices were monolithically fabricated in 150 mm silicon-on-insulator (SOI) technology. Si (111) was used as the device silicon layer to support a high C-axis oriented growth of AlN. The fabricated micromirror devices were characterized in terms of their scanning and sensor characteristics in air. A scan angle of 91.2° was reached for Design 1 at 13 834 Hz and 50 V. For Design 2 a scan angle of 92.4° at 12 060 Hz, and 123.9° at 13 145 Hz, was reached at 50 V for the x- and y-axis, respectively. The desired 2D scan patterns were successfully generated. A sensor angle sensitivity of 1.9 pC/° was achieved.

The cellular ratio of immune tolerance (immunoCRIT) is a definite marker for aggressiveness of solid tumors and may explain tumor dissemination patterns.

The adaptive immune system is involved in tumor establishment and aggressiveness. Tumors of the ovaries, an immune-privileged organ, spread via transceolomic routes and rarely to distant organs. This is contrary to tumors of non-immune privileged organs, which often disseminate hematogenously to distant organs. Epigenetics-based immune cell quantification allows direct comparison of the immune status in benign and malignant tissues and in blood. Here, we introduce the "cellular ratio of immune tolerance" (immunoCRIT) as defined by the ratio of regulatory T cells to total T lymphocytes. The immunoCRIT was analyzed on 273 benign tissue samples of colorectal, bronchial, renal and ovarian origin as well as in 808 samples from primary colorectal, bronchial, mammary and ovarian cancers. ImmunoCRIT is strongly increased in all cancerous tissues and gradually augmented strictly dependent on tumor aggressiveness. In peripheral blood of ovarian cancer patients, immunoCRIT incrementally increases from primary diagnosis to disease recurrence, at which distant metastases frequently occur. We postulate that non-pathological immunoCRIT values observed in peripheral blood of immune privileged ovarian tumor patients are sufficient to prevent hematogenous spread at primary diagnosis. Contrarily, non-immune privileged tumors establish high immunoCRIT in an immunological environment equivalent to the bloodstream and thus spread hematogenously to distant organs. In summary, our data suggest that the immunoCRIT is a powerful marker for tumor aggressiveness and disease dissemination.

A WD-FYVE protein binds to the kinases Akt and PKCzeta/lambda.

WD (tryptophan-aspartic acid dipeptide)-repeat proteins play a central role in signal transduction cascades by co-ordinating the interaction of key signalling molecules. We identified a novel propeller-FYVE [domain identified in Fab1p, YOTB, Vac1p and EEA1 (early endosome antigen 1)] protein, ProF, which is expressed in various cell lines and tissues and consists of seven WD-repeats and a FYVE domain. WD-repeat proteins offer a platform for protein-protein interactions by folding into a seven-bladed propeller-like structure, while the FYVE domain binds to phosphatidylinositol 3-phosphate present mainly on intracellular membranes. The ProF protein partially co-localizes with EEA1 on vesicular structures and binds to the protein kinases Akt and PKCzeta/lambda (protein kinase Czeta/lambda) via its WD-repeat propeller. ProF interacts more strongly with the kinases after hormonal stimulation. Endogenously expressed ProF and the two kinases interact in brain and in the preadipocyte cell line 3T3-L1, suggesting a role in secretory vesicular processes. In summary, we describe a new binding partner for kinases, located on vesicular structures in specialized cells, which may play a role for the spatial organization of signalling cascades.

Liquid crystalline nanowires in porous alumina: geometric confinement versus influence of pore walls.

Aligned liquid crystalline nanowires within ordered porous alumina templates show a pronounced texture on a macroscopic scale. We have investigated the influence of the geometric confinement and the nature of the pore walls on the mesophase formation by means of X-ray diffraction. The apparent texture is the result of a complex interplay of the pore geometry, interfacial phenomena, and the thermal history. Pores with a diameter of a few hundred nm guide the mesophase formation more efficiently than those with a diameter below 100 nm.

Regulation of Raf-Akt Cross-talk.

We have recently shown that the Ras-Raf-MEK-ERK and phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathways can cross-talk in the human breast cancer cell line MCF-7. High Raf activity induces growth arrest and differentiation in these cells, whereas high PI3K/Akt activity correlates with cell survival and proliferation. Here we show that the Raf-Akt cross-talk is regulated in a concentration- and ligand-dependent manner. High doses of insulin-like growth factor I (IGF-I) activate Akt quickly and strongly enough to suppress Raf kinase activity via phosphorylation of Ser-259, whereas low doses of IGF-I do not trigger this cross-talk but are still mitogenic. Phorbol 12-myristate 13-acetate, a differentiation-inducing stimulus, potently activates the Ras-Raf-MEK-ERK pathway but only weakly activates PI3K/Akt and does not trigger the cross-talk. Thus, the herein analyzed parameters such as ligand type, concentration, and time course may contribute to the cellular response of either proliferation or differentiation. This is highly relevant to understanding cellular transformation and may be of use in areas like tissue engineering.