הפקולטה להנדסה ע"ש איבי ואלדר פליישמן

EE Seminar: Yeast response to multiple carbon sources: a case study of combinatorial signal integration

~~(The talk will be given in English)

Speaker: Dr. Yonatan Savir
Faculty of Medicine, Technion

Sunday, May 8th, 2016
15:00 - 16:00
Room 011, Kitot Bldg., Faculty of Engineering

Yeast response to multiple carbon sources: a case study of combinatorial signal integration

Abstract
A major determinant of the fitness of biological systems is their ability to integrate multiple cues from the environment and coordinate their metabolism and regulatory networks accordingly. While much is known about the response to a single stimulus, our understating of combinatorial integration of multiple inputs is still limited. As a model system, we studied how yeast responds to hundreds of mixtures of preferred carbon source, glucose, and a less preferred one, galactose. Many of the components of this response, known as catabolite repression, are conserved from yeast to human. We found that, in contrast to the textbook view, instead of simply inhibiting galactose utilization when glucose is above a threshold concentration, individual cells respond to the ratio of glucose and galactose, and based on this ratio determine whether to induce genes involved in galactose metabolism. We investigate the genetic architectures that can result in a ratio sensing and how these architectures provide a fitness advantage which could have shaped the evolution of this property.

Bio: Dr. Yonatan Savir received his Bachelor’s degree from the Technion in Electrical Engineering and Physics and his PhD from the Dept. of physics of Complex Systems at the Weizmann Institute. He did his postdoctoral training at the Dept. of Systems Biology at Harvard Medical School. Dr. Savir joined the Faculty of Medicine at the Technion as a principal investigator in October 2015. His lab focuses on studying, both experimentally and theoretically, the signal processing that links nutrient sensing, uptake, growth rate and understating its system level failure in disease and in aged cells.

08 במאי 2016, 15:00

חדר 011, בניין כיתות-חשמל

Material Sciences and Engineering: Departmental Seminar

Nano Bio Mimetic; Nature's Gift

Prof. Oded Shoseyov

Protein Engineering and Nano-Biotechnology

The Robert H. Smith Institute of Plant Science and Genetic

The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot

04 במאי 2016, 16:00

Room 103, Engineering Class (Kitot) Building

Material Sciences and Engineering: Departmental Seminar

Nano Bio Mimetic; Nature's Gift

21 אפריל 2016

1/5/16

You are invited to attend a lecture

Electroactive Polymer Microactuators

Leeya Engel

Ph.D. student of

Professor Yosi Shacham-Diamand of Electrical Engineering, Physical Electronics Department and Professor Slava Krylov, of Mechanical Engineering, Tel Aviv University

The biomedical applications of electroactive polymer (EAP) actuators, also known as "artificial muscles", have the potential to vastly improve human life in tools for less invasive surgery, active prosthetics, and lab-on-a-chip devices. In this talk, I will present the emerging field of EAP micro-actuator systems, highlighting the actuation mechanisms of ionic and field-activated polymeric materials, while noting the importance of device scale. The main challenges inherent in developing these polymer microsystems lie in the integration of unconventional materials with silicon-based microsystems and the creation polymer-electrode interfacing that allows for chemically and mechanically stable operation. The goal of my work was to design and fabricate polymer microelectromechanical systems (MEMS) using novel EAP materials, which required actuator architectures and developing new microfabrication methodologies.

The main focus of the research was to explore the suitability of a promising relaxor ferroelectric polymer P(VDF-TrFE-CFE) for microsystems. This required developing custom micro/nanofabrication methodologies for patterning the smart material, such as thermoplastic nanoimprint lithography and developing an understanding of how processing conditions effect the material's electromechanical response. We demonstrated use of the material in two actuator configurations (1) A transparent buckling membrane actuator and (2) a self-sensing electroactive polymer bimorph actuator, which served as a platform for studying the frequency dependence of this EAP. In addition, we characterized the electromechanical response of a novel Pluronic-based biocompatible hydrogel developed for cardiovascular occlusion, shedding light on the role of current in the diffusion mechanisms behind electrically induced deformation of polymer hydrogels in salt solution.

Investigating the downscaled electromechanical and structural properties of smart polymers in actuator test structures contributes to the ”toolbox” of EAP actuator technologies by demonstrating feasibility and providing a scientiﬁc basis for understanding EAPs at small scales. These materials have the ability to exhibit property changes much beyond what is achievable with inorganic materials and, combined with their light weight, low-cost processing, flexibility and biocompatibility, present an attractive alternative material for device design. Recent advances in polymer microfabrication (i.e. imprint lithography, laser micromachining, and 3D printing), together with breakthroughs in materials science, and understanding of EAP behavior at these small scales will serve to overcome the technological barriers to full integration with microsystems and usher in a new paradigm of medical microsystems.

Sunday, May 1, 2016, at 11:10

Room 011, Kitot Building

01 במאי 2016, 11:10

1.5.16 Michael Kreiczer

You are invited to attend a lecture

Michael Kreiczer

(M.Sc. student under the supervision of Prof. Raphael Kastner

School of Electrical Engineering, Tel-Aviv University, Tel-Aviv 69978, Israel

Generalized Physical Aperture, Scattering and Absorption in antennas

While the effective area is well defined from power considerations for arbitrary antennas, small and slender antennas do not have a clear definition of their physical aperture. To adjust the definition for the general case, we can generalize the definition of the physical aperture as the ratio between the incident power to the power density of the incident plane wave. With the proposed definition, we can also generalize the definition of the aperture efficiency, which is known from large aperture antennas.

We can now define the Ideal Antenna, as the antenna whose generalized physical aperture is equal to unity.

The definition of the generalized physical aperture can also be related to the power balance, which can be defined straightforwardly by using the Poynting theorem over the surface enclosing the receiving antenna.

We show the relation between the power balance and the Optical Theorem, and by using earlier papers we will relate the directivity of the scattered pseudo power of the Ideal Antenna, to its directivity in transmit mode.

The case of super directivity is also discussed, being a critical issue when considering maximum available directivity for a given physical structure.

Sunday, May 1, 2016, at 16:00

Room 032, Labs Building

01 במאי 2016, 16:00

032 Maabadot

Wallace WF Leung סמינר מחלקתי בית הספר להנדסה מכאנית

09 במאי 2016, 11:55

וולפסון 206

Wallace WF Leung סמינר מחלקתי בית הספר להנדסה מכאנית

School of Mechanical Engineering Seminar
Monday, May 9, 2016 at 15:00
Wolfson Building of Mechanical Engineering, Room 206

Rotating microfluidics for Mixing and Process Intensification

Wallace WF Leung

Department of Mechanical Engineering, The Hong Kong Polytechnic University,

Hung Hom, Kowloon, Hong Kong

A novel method using transient inertial effect is used to mix a small milli- to micro-liter sample of different species in a rotating chamber. The primary flow generated from inertia induces a complex three-dimensional Coriolis flow that speeds up mixing by orders of magnitude in an otherwise viscous-force dominant micro-chamber. Experiments and numerical simulations are used to investigate the mixing due to the complex secondary flows generated. Such mixing and process intensification can be applied to cell culture, chemical reaction studies, and various other applications.

In a continuous-flow microchannel, a steady angular rotation generates throughflow down the channel by centrifugal acceleration, and at the same time the Coriolis acceleration generates crossflow that mixes fluids across the channel. The mixing can be carried out in either subcritical or supercritical mode depending on the channel width-to-height ratio. Experimental and numerical simulations have been used to confirm the results. A scale-up law on mixing is also presented based on dimensionless groups determined from Buckingham-π theorem.

סמינר המחלקה להנדסה ביו רפואית

08 במאי 2016, 14:00

חדר 315 הבניין הרב תחומי

Professor Ying Zhang

Division of embryonic biology

State Key Laboratory of Stem Cell and Reproductive Biology,

Institute of Zoology, Chinese Academy of Sciences,

Beijing, China

Molecular and biomechanical regulation of embryo distribution and location during pregnancy

The distribution and location of intrauterine embryo site(s) show conserved patterns in most mammalian species (in humans the embryo tends to implant in the uterine fundus while in rodents, embryos evenly distribute along the uterine horns). These long-term evolved embryo location pattern bears great significance for disruption of these pattern have adverse effects on pregnancy outcome. In the past ten years, we used different mouse models to study the molecular regulation of embryo distribution and found adrenergic signaling, aquaporins, steroid hormones are actively involved in intrauterine embryo distribution. Now we are working on the biomechanical aspects of embryo distribution regulation.

מיד לאחר הרצאת האורח:

עמית רוזנר -תלמיד המחלקה להנדסה ביו רפואית לתואר שני ירצה בנושא:

Termination of Atrial Spiral Wave Drivers by Induced Traction into Peripheral Non 1:1 Conducting Regions – A Numerical Study

Introduction: Atrial ablation has been recently utilized to treat atrial fibrillation (AF) by isolation or destruction of arrhythmia drivers. In chronic or persistent AF patients these drivers often consist of one or few rotors at unknown exact locations, and several ablation attempts are commonly conducted before arrhythmia activity is terminated. However, the irreversible damage done to the atrial tissue may lead to recurrence of AF within months or few years after the procedure. Here we propose an alternative strategy to terminate rotor activity by its attraction to a low-energy depolarizing probe and its traction into a peripheral non 1:1 conducting region.

Methods: The feasibility of the proposed method was numerically tested in 2D models of chronic AF human atrial tissue. Left-to-right gradients of either acetylcholine (ACh) or potassium conductance were employed to generate distinct regions of 1:1 and non 1:1 conduction, characterized by their dominant frequency (DF) ratios. Spiral waves were established in the 1:1 conducting region, and raster scanning pattern was employed using a stimulating probe to attract the spiral wave tip. The probe was then linearly moved towards the boundary between the two regions.

Results and conclusions: Successful attraction and anchoring of spiral waves to the probe was demonstrated for all scanning configurations when the probe was <8mm from the spiral wave tip. Maximal traction velocity without loss of anchoring increased in a non-linear, monotonic way with increasing values of ACh concentration. Success rate of spiral wave termination was over 90% for regional DF ratios of as low as 1:1.2 and 100% for ratios over 1:1.4. Given that normally much higher ratios are measured in physiological atrial tissues, we envision this technique to provide a feasible, safer alternative to ablation procedures performed in persistent AF patients.

העבודה נעשתה בהנחיית ד"ר שרון זלוצי'בר, המחלקה להנדסה ביו רפואית, אוניברסיטת תל אביב

ההרצאה תתקיים ביום ראשון 08.05.16, בשעה 14:00

בבניין הרב תחומי , חדר 315 אוניברסיטת תל אביב

סמינר המחלקה להנדסה ביו רפואית

01 במאי 2016, 14:00

חדר 315 הבניין הרב תחומי

Assessment of breast density and bilateral asymmetry for risk stratification and early detection of breast cancer

Dr. Dror Lederman

Breast cancer is the second most common type of non-skin cancer and the fifth most common cause of cancer death. It has long been shown that early detection of breast cancer may increase the treatment options, survivability, and chance for full recovery. Therefore, methods for earlier detection of breast cancer and risk stratification have long been of great interest. Mammography has been widely used for this purpose, both for screening and diagnosis. However, mammography interpretation suffers from relatively low detection sensitivity and specificity, especially in younger women (i.e., less than 50 years old), due to the low prevalence of breast cancer and denser breast tissue. In order to cope with this problem, we have been developing a novel methodology for mammography interpretation, which assesses the level of mammographic asymmetry between bilateral breasts as a major risk and diagnostic factor. The bilateral mammographic asymmetry information is combined with unilateral mammographic tissue information, to yield a fused risk-probabilistic model. In this talk, I will introduce our ongoing research work in this field, and in particular the proposed framework and set of algorithms that we have been developing for this purpose. I will also present our work on tissue density estimation. Some experimental results will be presented alongside with a discussion on the challenges and trends in this field of research.

Dror Lederman received the B.Sc., M.Sc. and Ph.D. degrees in Electrical and Computers Engineering in 1998, 2003 and 2009, respectively, and the B.EMS. (Bachelor in Emergency Medicine) degree in 2005, all from Ben-Gurion University of the Negev, Beer Sheba, Israel. Between 2009 and 2011 he was a research fellow at the Imaging Research Division, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA, where he was primarily involved in development of computer-aided diagnosis for breast cancer and lung computed tomography. Dr. Lederman is now a research scientist at Intel Corporation and a senior lecturer at the Holon Institute of Technology.

ההרצאה תתקיים ביום ראשון 01.05.16, בשעה 14:00

בחדר 315, הבניין הרב תחומי, אוניברסיטת תל אביב

EE Seminar: MST in Log-Star Rounds of Congested Clique

~~ (The talk will be given in English)

Speaker: Dr. Merav Parter
MIT

Sunday, May 1st, 2016
15:00 - 16:00
Room 011, Kitot Bldg., Faculty of Engineering

MST in Log-Star Rounds of Congested Clique

Abstract
We present a randomized algorithm that computes a Minimum Spanning Tree (MST) in O(log^* n) rounds, with high probability, in the Congested Clique model of distributed computing. In this model, the input is a graph on n nodes, initially each node knows only its incident edges, and per round each two nodes can exchange O(log n) bits.
Our key technical novelty is an O(log^* n) Graph Connectivity algorithm, the heart of which is a (recursive) forest growth method, based on a combination of two ideas: a sparsity-sensitive sketching aimed at sparse graphs and a random edge sampling aimed at dense graphs.
Our result improves significantly over the $O(\log \log \log n)$ algorithm of Hegeman et al. [PODC 2015] and the $O(\log \log n)$ algorithm of Lotker et al. [SPAA 2003; SICOMP 2005].
This join work with Mohsen Ghaffari, MIT, CSAIL.

Bio: Merav Parter is a Postdoctoral Fellow at MIT hosted by Prof. Nancy Lynch. She received a Ph.D. degree in Computer Science from the Weizmann Institute of Science under the guidance of Prof. David Peleg.
Her thesis "The Topology of Wireless Communication and Applications" won the first place Feder prize award for best student work in communication technology. Parter is a Rothschild and Fulbright Fellow.
In the past, she was a Google European Fellow in Distributed Computing, 2012. Her research interests focus on two aspects of reliable communication: fault tolerant graph structures and wireless communication. She's particularly intrigued with bridging the gap between Electrical Engineering and Theoretical Computer Science.

01 במאי 2016, 15:00

חדר 011, בניין כיתות-חשמל

13 אפריל 2016

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