When Will I Ever Use This Stuff Anyway?

As instructors of an intermediate-algebra course at a large urban community college, we decided to use a service-learning project to help students understand and appreciate the mathematics that they were studying. This outcome transcended the classroom and best motivated mathematics students by helping them realize how important the subject is to their futures (Jenrette 1994)

Éljenek a tanulás lehetőségével az ország legkiválóbb műszaki intézményében : Berceli Tibor bemutatása

Interjú az IEEE Microwave Theory and Techniques Society életműdíjával kitüntetett, több évtizede a mikrohullámok viselkedését tanulmányozó, rubin-diplomás Berceli Tiborral

3D modelling of drug-coated balloons for the treatment of calcified superficial femoral arteries

Background/Objectives Drug-coated balloon therapy for diseased superficial femoral arteries remains controversial. Despite its clinical relevance, only a few computational studies based on simplistic two-dimensional models have been proposed to investigate this endovascular therapy to date. This work addresses the aforementioned limitation by analyzing the drug transport and kinetics occurring during drug-coated balloon deployment in a three-dimensional geometry. Methods An idealized three-dimensional model of a superficial femoral artery presenting with a calcific plaque and treated with a drug-coated balloon was created to perform transient mass transport simulations. To account for the transport of drug (i.e. paclitaxel) released by the device, a diffusion-reaction equation was implemented by describing the drug bound to specific intracellular receptors through a non-linear, reversible reaction. The following features concerning procedural aspects, pathologies and modelling assumptions were investigated: (i) balloon application time (60–180 seconds); (ii) vessel wall composition (healthy vs. calcified wall); (iii) sequential balloon application; and (iv) drug wash-out by the blood stream vs. coating retention, modeled as exponential decay. Results The balloon inflation time impacted both the free and specifically-bound drug concentrations in the vessel wall. The vessel wall composition highly affected the drug concentrations. In particular, the specifically-bound drug concentration was four orders of magnitude lower in the calcific compared with healthy vessel wall portions, primarily as a result of reduced drug diffusion. The sequential application of two drug-coated balloons led to modest differences (~15%) in drug concentration immediately after inflation, which became negligible within 10 minutes. The retention of the balloon coating increased the drug concentration in the vessel wall fourfold. Conclusions The overall findings suggest that paclitaxel kinetics may be affected not only by the geometrical and compositional features of the vessel treated with the drug-coated balloon, but also by balloon design characteristics and procedural aspects that should be carefully considered

Functional Clustering of Periodic Transcriptional Profiles through ARMA(p,q)

Background: Gene clustering of periodic transcriptional profiles provides an opportunity to shed light on a variety of biological processes, but this technique relies critically upon the robust modeling of longitudinal covariance structure over time. Methodology: We propose a statistical method for functional clustering of periodic gene expression by modeling the covariance matrix of serial measurements through a general autoregressive moving-average process of order (p,q), the socalled ARMA(p,q). We derive a sophisticated EM algorithm to estimate the proportions of each gene cluster, the Fourier series parameters that define gene-specific differences in periodic expression trajectories, and the ARMA parameters that model the covariance structure within a mixture model framework. The orders p and q of the ARMA process that provide the best fit are identified by model selection criteria. Conclusions: Through simulated data we show that whenever it is necessary, employment of sophisticated covariance structures such as ARMA is crucial in order to obtain unbiased estimates of the mean structure parameters and increased precision of estimation. The methods were implemented on recently published time-course gene expression data in yeast and the procedure was shown to effectively identify interesting periodic clusters in the dataset. The new approach wil

Millimeter wave detection by thermopile antenna

AbstractIn this paper a novel MEMS thermopile structure is proposed, which consist of linearly arranged p- and n- type polysilicon strips instead of the conventional loop-like configuration. It is shown that these devices sense the millimeter wave radiation beyond the infrared. The polarity and frequency dependence of the sensitivity prove that these strips behave as absorbing antennas towards the microwave/millimeter wave radiation. The induced current is calculated having a maximum in the geometrical center of the antenna, exactly at the position where the hot end of the thermopair is located. The measured responsitivities to direct heating, infrared radiation, 13 GHz microwave radiation and 100 GHz millimeter-wave radiation are presented