Yearly Archives: 2014
An interdisciplinary research group from the Technion revealed for the first time the optical role of glial cells in the retina for the improvement of vision. Until today, the retina was known for its conversion of light into electric signals as well as the initial processing of the visual information. However, the Technion group showed that the retina is also a sophisticated optical structure.
The retina of the eye: Light, arriving from above, is guided towards the photoreceptors (blue layer at the bottom) by glial cells acting as optical fibers. The glial cells sort the light by its colors, where the green and red (shown) pass into the corresponding cones, while the blue-violet is scattered to nearby rods.
The research shows how light passes the eye to fall on the retina, only to be separated into colors by funnel-shaped glial (Müller) cells, functioning as optical fibers spanning the retinal depth.
These cells collect and guide efficiently the green-red colors down to the cone photoreceptors, the light detectors responsible for day time color vision, and, at the same time, allowing the blue and violet colors to scatter out to the surrounding rod photoreceptors, active at night time. This color separation improves the daytime peripheral vision up to ten times, without impairing night vision.
The light guiding and color sorting explain why the vertebrate retina has a seemingly inverted structure, with photoreceptors set behind layers of neural cells and cell nuclei, rather than in front of them.
The researchers built a computer model predicting the color guiding in the retinas of humans and other diurnal mammals. This model was validated in the laboratory, where light was measured while passing through the retina, along the glial cells, down to the photoreceptors. Indeed, the experiments showed the concentration of green-red light inside the glial cells, down to the cones, with the blue-violet colors to the nearby rods.
The research was performed by graduate students Amichai Labin and Shadi Safuri, supervised by Erez Ribak and Ido Perlman, from the Faculties of Physics and Medicine, and was published in Nature Communications.
Assistant Professor Avi Avital is taming rats to detect explosives and construct animal models as a working platform for the treatment of diseases such as schizophrenia.
Assistant Professor Avi Avital from the Technion’s Rappaport Faculty of Medicine, is training rats in an attempt to build (along with Professors Moshe Gabish and John Finberg) – a working model for the treatment of neurodegenerative diseases such as Parkinson’s and Huntington. He recently built a working model to validate symptoms of schizophrenia: “We gave rats a low sub-anesthetic dose of ketamine (a veterinary anesthetic) and exposed them to stress to build a working model for the treatment of schizophrenia – for an understanding of the factors responsible for disease outbreak and experimental platforms for drug development.”
איור המתאר את מעבדתו ואופן עבודתו של פרופוסר משנה אביטל
As part of an applied research study, Assistant Professor Avital succeeded in taming rats to detect explosives. “Rats have a highly developed sense of smell and we succeeded in taming them to identify scents of explosive materials,” he said. “The insights from a study of rat models are being implemented in dog training in a collaborative study with the Israel Ministry of Defense and the United States Army (USA).”
“In an extensive mapping study we conducted, we exposed rats to stress at different periods of their lives, and we found that the critical period for exposure to stress is during the same transition period between childhood and adolescence in humans,” he said.
On the account of an NIH grant from the American Defense Department, Assistant Professor Avital built a sophisticated laboratory of behavioral biology, which is studying rats mainly in the area of attention and social interaction, in combination with behavioral aspects of physiological and pharmacological research. In parallel of performing his clinical research, which he conducts at the Emek Medical Center in Afula, he continues his work with dogs. Recently, he developed a device that simulates explosive materials as part of a systematic and safe dog training process. In this field he newly demonstrated the importance of the link between stress level and attention of a dog’s customary ability to execute various tasks. He also found that if the dog detects one type of explosive, he is capable of generalizing and identifying other types of explosives. “We have shown that this ability to generalize is found in the same brain region of both dogs and rats,” he explained.
Assistant Professor Avital developed a way to train rats through behavioral shaping procedures. He clothes rats with a “vest” that is connected to tiny metals imbedded under the rat’s skin (using a minimal-pain procedure). The rat feels a light tap – he taught them that when the tap is felt on the right hand side to turn left, and vice versa. When tapping both shoulders, the rat will stop, etc.
In the study investigating social cooperation, Assistant Professor Avital built a labyrinth that is controlled automatically by software and a camera through which rats learn social cooperation. “Female rats cooperate better than males,” he emphasized.
Assistant Professor Avital’s work is unique because it is beyond translational science (circumspect conclusions of a rat model to humans); he conducts half translational science, that is: he makes inferences from one animal (rats) to another (dogs). Using behavioral, physiological and pharmacological methods, Assistant Professor Avital focuses on attention and social cooperation in all research levels aforementioned.
In the photo:
A lab rat and an illustration depicting the laboratory and Assistant Professor Avital’s work methods.
The video displays a rat dressed in a “vest.”
Pilot study of circadian rhythm changes in human serum lipids and oxidative stress: effects of Pomegranate extract (POMx), Simvastatin, and Metformin therapies in hypercholesterolemic and diabetic patients vs. healthy subjects
The Lipid Research Laboratory, Rambam Health Care Campus, The Rappaport Faculty of Medicine and Research Institute, Technion- Israel Institute of Technology, Haifa
The present pilot study analyzed lipids, oxidative stress and antioxidants and their ability to affect macrophage atherogenicity, in sera from healthy subjects and from hypercholesterolemic or diabetic patients, collected during a 24 hour cycle, before and after treatment with pomegranate extract (POMx), simvastatin, or metformin.
In healthy subjects, but not in hypercholesterolemic patients, HDL-cholesterol levels showed circadian changes with maximal levels in the afternoon. In diabetics, serum LDL-cholesterol levels showed circadian rhythms, with an increase in the afternoon followed by a decrease during the evening. After POMx or metformin treatment, these circadian changes were completely abolished. We conclude that circadian rhythms exist in levels of human serum lipids, glucose, and oxidative stress, as well as in macrophage atherogenicity. Appropriate treatment (antioxidant, hypocholesterolemic, or anti-diabetic) may be indicated according to the circadian pattern.
Tony Hayek1,2#, Mira Rosenblat2#, Nina Volkova2, Judith Attias3, Riad Mahamid1 , Shadi Hamoud1, Michael Aviram2*
Figure explanation: “The biological clock of blood lipids”.
Circadian changes in blood levels of cholesterol, LDL (“the bad cholesterol”), HDL (“the good cholesterol”) and triglycerides , along 24 hours of the day in healthy subject.
Technion researchers are part of an international team of scientists who discovered a swiftly moving gas streamer eclipsing a supermassive black hole
An international team of astronomers, including Prof. Ehud Behar and Dr. Shai Kaspi from the Technion’s Physics Department has discovered that the supermassive black hole at the heart of the galaxy NGC 5548 has recently undergone strange, unexpected behavior rarely seen in the heart of active galaxies. The researchers detected a clumpy gas stream flowing quickly outward and blocking 90 percent of the X-rays emitted by the supermassive black hole at the center of the galaxy.
This activity may provide new insights into the interaction of supermassive black holes and their host galaxies.
This discovery was accomplished through an intensive observing campaign with the major ESA and NASA space observatories: XMM-Newton, the Hubble Space Telescope, Swift, NuSTAR, Chandra, and INTEGRAL. An international team led by scientist Jelle Kaastra, of the SRON Netherlands Institute for Space Research conducted the most extensive monitoring campaign ever of an active galaxy in 2013 and 2014.
ציור של האזור המרכזי של NGC 5548 (לא בקנ”מ מדויק). הדיסקה סביב החור השחור מפיצה קרני X וקרינה אולטרה-סגולה, אופטית ואינפרה-אדומה ומוקפת בטבעת אבק. הקווים הקמורים מציינים את זרם הגז הנע לאורך קווי השדה המגנטי של הרוח של דיסקת הספיחה. האזור המעורפל עשוי מתערובת של גז מיונן ובתוכו חלקים צפופים וקרים יותר, והוא קרוב יותר לאזור הפנימי של פליטת קרינת אולטרה-סגול. אזור הקו הצר וקולט-החום נמצאים יותר בחוץ.
“We have been observing outflows from active galaxies in detail for over a decade, but have yet to crack their operating mechanism. The present observations are the first time we apparently caught the launch of such a wind and were able to measure its high velocity. ” said Ehud Behar a world renown expert on X-ray spectroscopy of outflows from active galaxies.
The researchers say that this is the first direct evidence for the long-predicted shielding process that is needed to accelerate powerful gas streams, or “winds,” to high speeds. The team reports that this is a milestone in understanding how supermassive black holes interact with their host galaxies.
These results are being published in the June issue of Science magazine.
Matter falling onto a black hole gets heated and emits X-rays and ultraviolet radiation. The ultraviolet radiation can launch winds outward. The winds may be so strong that they can blow off gas that otherwise would have fallen onto the black hole. Black hole winds can therefore regulate both the growth of the black hole and its galaxy. If the falling gas feeds the black hole, the newly discovered outflow is evidence for its eating disorder.
But the winds may only come into existence if their starting point is shielded from X-rays. The newly discovered gas stream in the archetypal Seyfert galaxy NGC 5548 — one of the best-studied sources of this type over the past half-century — provides this protection. It appears that the shielding has been going on for at least three years.
Right after the Hubble Space Telescope had observed NGC 5548 on June 22, 2013, the team discovered dramatic changes since the last observation with Hubble in 2011. They observed signatures of much colder gas than was present before, indicating that the wind had cooled down, due to a strong decrease of ionizing X-ray radiation from the nucleus.
After combining and analyzing data from the six observatories, the team was able to put the pieces of the puzzle together. Supermassive black holes in the nuclei of active galaxies, such as NGC 5548, expel large amounts of matter through powerful winds of ionized gas. For instance, the persistent wind of NGC 5548, known for two decades, reaches velocities exceeding 1000 km/s.
But now a new wind has arisen, much stronger and faster than the persistent wind. “The new wind reaches speeds of up to 5,000 kilometers per second but is much closer to the nucleus than the persistent wind,” Kaastra said. “The new gas outflow blocks 90 percent of the low-energy X-rays that come from very close to the black hole, and it obscures up to a third of the region that emits the ultraviolet radiation at a few light-days distance from the black hole.”
Further information
These results are published in Science:
http://www.sciencemag.org/content/early/2014/06/18/science.1253787.full
“A fast and long-lived outflow from the supermassive black hole in NGC 5548”, by Kaastra et al.
Team:
The team consists of Jelle Kaastra (SRON Utrecht, The Netherlands), Jerry Kriss (Space Telescope Science Institute, Baltimore, USA), Massimo Cappi (INAF-IASF Bologna, Italy), Missagh Mehdipour (SRON Utrecht, The Netherlands), Pierre-Olivier Petrucci (Univ. Grenoble Alpes, CNRS, France), Katrien Steenbrugge (Universidad Católica del Norte, Antofagasta, Chile), Nahum Arav (Virginia Tech, Blacksburg, USA), Ehud Behar (Technion-Israel Institute of Technology, Haifa, Israel), Stefano Bianchi (Università degli Studi Roma Tre, Italy), Rozenn Boissay (University of Geneva , Switzerland), Graziella Branduardi-Raymont (MSSL/UCL, Holmbury St. Mary, UK), Carter Chamberlain (Virginia Tech, Blacksburg, USA ), Elisa Costantini (SRON Utrecht, The Netherlands), Justin Ely (Space Telescope Science Institute, Baltimore, USA), Jacobo Ebrero (ESA, Spain), Laura Di Gesu (SRON Utrecht, The Netherlands), Fiona Harrison (California Institute of Technology, Pasadena, USA), Shai Kaspi (Technion-Israel Institute of Technology, Haifa, Israel), Julien Malzac (Université de Toulouse, France), Barbara De Marco (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), Giorgio Matt (Università degli Studi Roma Tre, Italy), Paul Nandra (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), Stéphane Paltani (University of Geneva , Switzerland), Renaud Person (St. Jorioz, France), Brad Peterson (Ohio State University, Columbus, USA), Ciro Pinto (University of Cambridge, UK), Gabriele Ponti (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), Francisco Pozo Nuñez (Ruhr-Universität Bochum, Gernmany), Alessandra De Rosa (INAF/IAPS, Roma, Italy), Hiromi Seta (Rikkyo University, Tokyo, Japan), Francesco Ursini (University of Grenoble, CNRS, France), Cor de Vries (SRON Utrecht, The Netherlands), Dom Walton (California Institute of Technology, Pasadena, USA), Megan Whewell (MSSL/UCL, Holmbury St. Mary, UK).
Movie:
A new creation by Renaud Person, one of the Worlds Director of the famous video game Assassin’s Creed © Ubisoft. The movie brings us in a journey to the inner regions of NGC5548, and helps us in visualizing the findings presented in this study.
www.sron.nl/~kaastra/press5548/NGC5548_Obscurer_H264.mov
An animated journey through the active galaxy NGC 5548.
At its center is a supermassive black hole that is 40 million times heavier than our Sun, all concentrated in a region smaller than the Earth’s orbit around the Sun. Gas swirls around this black hole and is sucked into it, heating up its surroundings and producing strong energetic X-ray radiation. This X-ray hot corona is fuelled through a rapidly rotating accretion disk. The disk also produces strong patchy winds of warm gas that is thrown out into space. It contains denser parts that may obscure the X-rays emitted in the direction towards the Earth, shown by the green line. Further outwards we see the winds produced by the outer parts of the rotating disk, where the so-called broad line clouds are. At light years away from the black hole the warm winds also absorb some of the X-ray and ultraviolet light from the nucleus. These winds can cool down when the obscuring inner clouds block the light from the nucleus. The power emitted by the nucleus is so strong that it affects major parts of the host galaxy. The galaxy has a size of hundred thousand light years and is at a distance of 240 million light years away from us.
Ishai Zimerman and his son-in-law Ronen Atzili are the 2014 Technobrain first prize winners for building a device that successfully climbed up a steep cable at a high speed while being powered by an electric screwdriver. They will be awarded a 10,000 NIS cash prize.
At this year’s competition, Technobrain competitors were required to build a device that could climb up to a height of 25 meters in a nearly vertical manner, and then slide down from this height while lifting a “space elevator” suspended from the other side of the cable. This challenge was made further difficult because of the provision prohibiting the use of combustion or open flame energy sources of any kind.
This is the third time that Zimerman is competing in Technobrain, and Atzili’s second time. “My granddaughter was surfing the net one day and saw an advertisement for the completion and, she thought it would interest me, knowing of my sportive and creative spirit,” related Zimerman, who operates a locksmith’s workshop in Kibbutz Ein Harod and is in his 80’s.
הסטודנטים הזוכים בתחרות במקומות הראשונים.
“The idea of basing the engine on an electric screwdriver we borrowed from the world of manufacturing plastic pipes using plastic extrusion, in which raw plastic material is melted and formed into a continuous profile,” said Atzili. “In short, it’s an idea that came to me originating from my experiences working in the plastics industry.”
Do you have plans for what to do with the prize money?
“We’ll use it to cover the costs of this year’s competition, and whatever is left over we’ll use to cover expenses of next year’s competition!”
The Technobrain Competition is in memory of Neev-Ya Durban, who was an outstanding Technion graduate, and is funded by Dr. Robert Shillman (who everyone knows as “Dr. Bob”), who did his graduate work at the Technion.
The engineer Yuri Artsutanov who developed the concept of the “space elevator” was the guest of honor and one of the judges of the competition. He published his idea, which was based on the proposal by Konstantin Tsiolkovsky, in the 1950’s. Artsutanov’s visit to the Technion was supported through the Dean of Students Office, the Asher Space Research Institute (ASRI), and the foundation founded by family members of Norman and Helen Asher from Chicago. This was his first trip to Israel. “The competition was very fun and entertaining,” he said.
The work of assistant Professor Shelly Tzlil is an enlightening example of interdisciplinary research: in her undergrad degree she completed a dual major in chemistry and computer science, her graduate research (MSc and PhD) was in physical chemistry, and her postdoc focused on polymer chemistry. She is a biophysicist, who started off as a theoretician turned experimentalist and today study mechanical sensing in living cells at the Faculty of Mechanical Engineering.
What do biological cells have to do with mechanical engineering? “Typically when you think about communication of cells with their environment, you think about chemicals that cells release and absorb,” explains Tzlil. “But in recent years scientists realize that cells also respond to mechanical forces, such as flow or distortion (deformation) of material that they interact with. Cells bind to their environment, exert forces on it, and unravel its elastic properties by ‘measuring’ the deformations these forces induce. In the case of cultured stem cells, for example, something very surprising occurs – the cells attempt to match the degree of their intrinsic elasticity – their flexibility – to that of the environment and this ‘elastic-matching’ tendency dictates the cell type they will differentiate into. If the environmental elasticity is similar to brain tissue, it will differentiate into neuron, and if this elasticity is like that of a muscle, it will differentiate into muscle cell.”
“In light of this phenomenon, the identity of the investigator and his discipline, greatly affects the type of research questions raised. “While physicists and chemists will ask – ‘How do cells sense elasticity?’ biologists might ask – ‘What is the evolutionary advantage of such a mechanism?’ And medical doctors would want to know how such a mechanism will manifest itself in health and disease,” explains Assistant Professor Tzlil. “I am interested in exploring how cells are able to ‘feel’ the mechanics of their environment, and how they communicate by deforming their environment mechanically.”
“Mechanical engineers study the way material responds to mechanical forces, and how to measure and apply them. They view the cell as a machine with control mechanism and this drive them to ask different type of questions, such as ‘how does the cell ‘know’ how much force to apply?’ It’s a different way of thinking. In interdisciplinary work of this kind both sides have to make an effort to understand one another. I found this willingness in the Faculty of Mechanical Engineering.”
The Technion is a natural playground for this type of interdisciplinary work. “At the Technion the collaboration between medicine and engineering already exists, and I knew I’d be able to find a multidisciplinary working environment that would both suit me and enrich me. My research requires a continuous dialogue with engineers, biologists, medical doctors, theoreticians and experimentalists and the Technion is an ideal place for such integration. Theoretically, I could have found myself in biology, biotechnology engineering or biomedical engineering. The advantage of working in mechanical engineering for me is the toolbox I have here – and of course the excellent partners I’ve made in the fields of elasticity, dynamics and more. I bring to the mechanical engineering faculty the biological aspect, the study of soft matter and the focus on the cellular and molecular levels – aspects that do not belong to traditional areas of mechanical engineering. I came here because I thought that this interaction between the two worlds can lead to an interesting outcome.”
***
Shelly Tzlil was born in Rishon LeZion, and all of her degrees – her undergrad in chemistry and computer science, and her graduate degree in physical chemistry were completed at the Hebrew University in Jerusalem. In her doctoral studies she investigated processes such as the mechanics of DNA packaging in viruses, and protein adsorption on membranes. “My doctoral thesis was in theoretical biophysics – developing models that can explain biological processes. Over time, I realized that as a theoretician, I’m dependant on experimentalists to perform the experiments that interest me. As an experimentalist, I can design and conduct my own experiments to test our theories.”
Tzlil has done her postdoc at Caltech, working with Professor Dave Tirrell, a polymer chemist. “Tirrell knows how to “program” bacteria to operate as a polymer factory producing artificial proteins with unique functionalities.”
The research currently being conducted at Associate Professor Tzlil’s laboratory examines the implications of mechanical interactions between cells and the biological mechanism that enables it. Additionally, new biomaterials are designed that are able to increase the range of mechanical interaction between cells and simulate the physiological environment.
“Usually, biological interactions based on chemical or electrical signals are short range. Mechanical interactions can be felt in large distances. Cardiac cells, for example, can sense mechanical forces hundreds of microns away. It implies that cardiac cells can ‘feel’ each other and synchronize their beating without physical contact, especially when they are on an elastic substrate characteristic of a healthy tissue.”
Assistant Professor Shelly Tzlil believes that her research will enable the design of materials that will allow control over the rate and direction of nerve cell growth after injury. “As part of the research I’m developing bio-materials that increase the range of mechanical interactions between cells as well as materials that simulate the mechanical physiological environment,” explains Prof. Tzlil. “Materials that can effectively conduct mechanical deformations have the potential to control the rate and direction of nerve cell growth after injury.”
A warm welcome to our governors and friends from around the world who have joined us to celebrate Technion’s outstanding achievements and contributions on the national and global stages, and to look ahead to tomorrow’s challenges and promises.
The entire Technion community – faculty, students, staff and alumni – is grateful for the heartfelt generosity of our many supporters from Israel and across five continents.
תכנית מושב הקורטריון
BOG Meeting Program
MAP/מפה
Technion Scientists Develop ‘Test Tube Brain Tissue’ that Provides a 3-D View of Neural Activity
The new ‘Optonet’ cultures could enable a better understanding of complex activity within neural networks
Neural cells grown on laboratory plates (two-dimensional neural cultures) constitute a convenient model for many studies in the field of neuroscience and medicine. Their main advantage is the relative simplicity by which they can be used to examine physiological changes in neural cells’ activity patterns caused by changes in their environment. However, the shortcomings of these simple 2D cultures is that they contain only a single layer of cells, and do not exhibit the complex three-dimensional network connectivity found in real brains. Previous attempts to develop 3D models for studying the central nervous system have met with limited success, mainly due to the high complexity of developing a 3D culture capable of simulating brain tissue as well as challenges associated with developing methods for observing network activity in three dimensions. Technion researchers led by Professor Shy Shoham from the Department of Biomedical Engineering now report in Nature Communications that they were able to develop, for the first time, three dimensional cell networks that can simulate complex aspects of brain activity, which could provide a better access for understanding the physiology of the central nervous system.
המחשה של המיקרוסקופ אותו בנינו במעבדה. על ידי שימוש בטכניקה מתקדמת, הנקראת מיקוד זמני, ניתן לדמות ביעילות ובמהירות איזורים גדולים בתרבית. כל נקודה בתרבית מצולמת 10 פעמים בשניה, מהירות המאפשרת לזהות כל שינוי בפעילות התאים.
The Editors of Nature Communications note that three-dimensional neural networks represent a promising model of complex neural tissue, which may lead to a better understanding of the structure and function of the brain, and that the Technion researchers also present an advanced method for viewing the neural activity of the engineered culture using a fast microscopy system they developed.
Prof. Shoham and his research team, which included Dr. Hod Dana, Dr. Anat Marom, Shir Paluch, Roman Dvorkin and Dr. Inbar Brosh, explain that they grew the advanced culture in a clear gel that supports cellular growth and allows the cells to bind and form neural networks. “By optimizing the culturing conditions we achieved cellular density and composition similar to those found in the human brain, and were able to demonstrate the formation of connections between cells and of networks that maintain neural activity,” says Dr. Marom. To enable the study of network activity in 3D, optical tools were used: nerve cells in the cultures were genetically altered making it possible to view ongoing network activity through a fluorescence microscope, earning them the nickname “Optonets”.
To view cell activity in 3-D, the researchers developed an advanced imaging system that uses ‘temporal focusing’– a non-linear optical technique developed nearly a decade ago at the Weizmann Institute of Science. “The hybrid SLITE imaging system we developed is a significant step forward in improving research capabilities for viewing the activities of multiple brain cells in space and time through which we may be able to reach insights about brain activity,” explains Dr. Dana.
“Through complementary advances in microscopy and in neural tissue engineering we demonstrated an unprecedented ability to view more than a thousand cells within developing neural networks, exhibiting complex spontaneous activity patterns. These innovations open new windows of opportunity for further developments in the field of neural interfaces and other applications for 3-D engineered networks, ranging from basic brain research to the examination of the impact of neurological drugs on nerve cell activity”, summarizes Prof. Shoham.
In the photos:
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Illustration of the Technion team’s SLITE microscope, which uses advanced optics to image the 3D culture at a rate of 10 images per second – fast enough to follow neural activity.
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Optonets placed over text to illustrate their translucency; the images were taken on different days during the culture’s growth and development.
Clip:
The video shows activity imaged in a culture region containing approximately 1,000 cells, revealing synchronized spontaneous activity bursts in adjacent groups of cells. Neural activity is indicated by changes in the cells’ color.