Polygonal micro-whirlpools induced in ferrofluids

We report on the observation of the polygonal whirlpools in the thin layer of ferrofluid under illumination with a laser beam carrying optical vortex and in the presence of a vertical magnetic field. This kind of structures have attracted attention after discovering a hexagonal storm in Saturns atmosphere. Our polygonal whirlpools were created in a closed system (no free surfaces) in micro scale (whirlpool diameter less than 20 micrometers) by the use of holographic optical tweezers. The polygonal shape was changed by varying the magnetic field strength or value of the optical vortex topological charge

Micro-Dumbbells—A Versatile Tool for Optical Tweezers

Manipulation of micro- and nano-sized objects with optical tweezers is a well-established, albeit still evolving technique. While many objects can be trapped directly with focused laser beam(s), for some applications indirect manipulation with tweezers-operated tools is preferred. We introduce a simple, versatile micro-tool operated with holographic optical tweezers. The 40 µm long dumbbell-shaped tool, fabricated with two-photon laser 3D photolithography has two beads for efficient optical trapping and a probing spike on one end. We demonstrate fluids viscosity measurements and vibration detection as examples of possible applications

Different levels of let-7d expression modulate response of FaDu cells to irradiation and chemotherapeutics.

The implication of the let-7 family in cancer development is multifaceted. The family acts as tumor suppressor miRNA although overexpression of let-7 has also been described in many types of cancer, including head and neck squamous cell carcinoma (HNSCC). The aim of this study includes whether different expression levels of let-7d has an influence on chemo- and radiosensitivity. FaDu cell line models with a gradually increased level of let-7d (models from A to E) were generated with the lentiviral system. Expression levels of pluripotency, chemo-radioresistance/apoptosis, and targets of mRNAs were analyzed by real-time reverse transcription-PCR (qRT-PCR). Radiosensitivity was analyzed using a clonogenic assay after irradiation. Response to cisplatin, 5-FU, doxorubicin, and paclitaxel was done with MTT assay. Statistically significant decrease of K-RAS (p = 0.0369) and CASPASE3 (p = 0.0342) were observed with the growing expression level of let-7d. Cisplatin, 5-FU and doxorubicin caused similar decreased of cell survival with the increase of let-7d level (p = 0.004, post-trend p = 0.046; p = 0.004, post trend p = 0.0005 and p<0.0001, post trend p = 0.0001, respectively). All models were resistant to paclitaxel, irrespective of let-7d expression levels. Only two of the generated models (A and C) were radiosensitive (p = 0.0002). CONCLUSION:the above results indicated that the level of let-7d expression is an important factor for cell response to irradiation and chemotherapeutics

Tumor microenvironment – Unknown niche with powerful therapeutic potential

Head and neck squamous cell carcinomas (HNSCC) are in a group of cancers that are the most resistant to treatment. The survival rate of HNSCC patients has been still very low since last 20 years. The existence of relationship between oncogenic and surrounding cells is probably the reason for a poor response to treatment. Fibroblasts are an important element of tumor stroma which increases tumor cells ability to proliferate. Another highly resistance, tumorigenic and metastatic cell population in tumor microenvironment are cancer initiating cells (CICs). The population of cancer initiating cells can be found regardless of differentiation status of cancer and they seem to be crucial for HNSCC development.In this review, we describe the current state of knowledge about HNSCC biological and physiological tumor microenvironment

Expression of genes characteristic for.

<p>A) pluripotency (OCT3/4, SOX2, NANOG) and B) let-7d targets: K-RAS, Caspase3, H-RAS, N-RAS, HMGA1, HMGA2, C-MYC, ARIDA3A, DICER; C) genes connected with chemo-radioresistance/apoptosis (BAX, ATM, ABCB1, BCL2); D) statistical analysis of models B-E indicated positive results for mRNAs: Caspase3, ATM, K-RAS, N-RAS, HMGA1, and ARID3A.</p