Monday, December 4, 2017

3D printing of bacteria into functional complex materials

A team from the ETH in Zurich and the University College in Dublin has been able to demonstrate a 3D printing approach to create bacteria-derived functional materials by combining the natural diverse metabolism of bacteria with the shape design freedom of additive manufacturing.

They have developed a biocompatible hydrogel with optimized rheological properties that allows for the immobilization of bacteria into 3D-printed architectures at a high accuracy. They have demonstrated two applications: degrading environmental toxins, and making cellulose, which can be used as scaffolds for skin replacements and coatings for biomedical devices that help protect patients against organ rejection.

Immobilization of Pseudomonas putida, a known phenol degrader, when printed allows to degrade phenol into biomass, showing the potential of the 3D bacteria printing platform for biotechnological applications. Immobilization of Acetobacter xylinum in a predesigned 3D matrix enables the in situ formation of bacterial cellulose scaffolds on nonplanar surfaces, relevant for personalized biomedical applications.

Science Advances 01 Dec 2017: Vol. 3, no. 12, eaao6804 DOI: 10.1126/sciadv.aao6804

Schematics of the 3D bacteria-printing platform for the creation of functional living materials

Tuesday, November 14, 2017

AAAS Statement on Scientific Freedom and Responsibility

Scientific freedom and scientific responsibility are essential to the advancement of human knowledge for the benefit of all. Scientific freedom is the freedom to engage in scientific inquiry, pursue and apply knowledge, and communicate openly. This freedom is inextricably linked to and must be exercised in accordance with scientific responsibility. Scientific responsibility is the duty to conduct and apply science with integrity, in the interest of humanity, in a spirit of stewardship for the environment, and with respect for human rights.

For more information:

Camille Flammarion: "Urbi et Orbi”, in L'atmosphère: météorologie populaire, 1888

Where the sky and the Earth touch

Thursday, November 9, 2017

Panasonic buying deep learning startup

Arimo was born Adatao in 2013 and is being acquired by Panasonic. It calls its product Behavioral AI and targets it to machine learning for Industry 4.0.

It started with two tools. pAnalytics is a Spark environment providing an API where developers can work with the data and expose it to the end users with charts and graphs. pInsights is the end user layer, which takes natural language queries. This tool learns from the end user's interactions and can suggest possible queries.

This approach is used to learn from the past behavior of equipment to identify complex anomalies that are hard to predict with traditional statistical modeling. The same deep learning algorithms can also be used to predict retail shopper's behavior to offer them incentives and optimize store inventories. A related solution area is financial services, where the technology can find signals and anomalies in large-scale transactional data to detect fraud, model risk, and predict investor or consumer behavior.

Panasonic first aims to apply the technology to data on business refrigerators for supermarkets and convenience stores. It envisions a service reducing energy consumption for a store chain overall by setting optimal operating patterns for individual stores, based on past data on refrigerators' internal temperature and energy use. Panasonic can then expand the application to industrial air conditioners.

In the future, Panasonic plans services to manage the physical health of the elderly based on data from appliances and a range of sensors. Since Panasonic has few data analysis experts, Arimo will be a training ground for its employees.


Friday, November 3, 2017

3d face recognition

This morning, #45 announced a massive tax relief for the American people. Also as of this morning, the new iPhone X is available for purchase in Apple stores.

If you are investing your massive tax relief in an iPhone X, do not just look at the gorgeous OLED screen, but also at the 3d face recognition sensor, because you have been reading about the underlying physics on this blog.

It has been over a dozen years since Neil J. Gunther of Performance Dynamics, annoyed by a Harvard professor's claim of having disproved Bohr's complementarity principle, proposed to follow the idea of VLSI design rules to formulate practical design rules for quantum communications and quantum imaging devices.

We performed interference experiments in Neil's kitchen using a green laser and a paper clip to form an image. Sergio Magistri noticed that doing physics is good, but creating an artifact that we could sell would be better. He hooked us up with Edoardo Charbon, who had invented a CMOS SPAD array.

After lengthy discussions, Edoardo—who in the meantime had become a professor at EPFL—was willing to reduce our ideas to practice. We received a 500,000 franc grant from the Swiss National Science Foundation to buy the lab equipment and a matching grant from the European Union to hire Dmitri Boiko as a postdoc.

To form the image, we used the metal plate creating the nozzles in an ink jet cartridge to obtain an array of pinholes.

We performed experiments supporting the concept of a g2-camera, summarized on this blog. The statistical post-analysis was so challenging that Neil had to implement it in the fast processor of an oscilloscope. We wrote two papers with the early details:

The blog posts hot body, excited particles, and the north sky and chaotic light sources are the basis for telling apart the sources for the photons reaching the SPAD array.

It is amazing that today the computations can be done on a small, inexpensive smartphone. However, it took 13 years and hundreds if not thousands of people to get to today's device, a simpler version of which, by the way, is also used in Bosch measures.


Thursday, October 5, 2017

Computational Near-Eye Displays with Focus Cues

SCIEN has resumed at Stanford with the talk Computational Near-Eye Displays with Focus Cues by Gordon Wetzstein. This presentation is an overview of research at Stanford.

Inflection points in near-eye displays:

  • 1838 Stereoscopes by Wheatstone, Brewster, …
  • 1968 Ivan Sutherland
  • 1995 Nintendo Virtual Boy
  • 2012–2017 VR explosion

Currently, the big enablers are the smartphone components.

The main purpose of the lenses in near-eye displays is to set the virtual image further away because we cannot focus too close.

Stereoptics is binocular; the mechanism of vergence is cued by binocular disparity. Focus cues are monocular; the mechanism of accommodation is cued by retinal blur.

The big problem is the vergence-accommodation conflict..

Gaze-contingent focus. For non-presbyopes, the adaptive focus is like the real world, but it requires eye tracking. Presbyopes need a fixed focal plane with correction.

Light field displays are not yet well-developed. The idea is to project multiple different perspectives into different parts of the pupil. Example: tensor displays. Light field displays are limited by diffraction.

The next step is multifocal lenses: point spread function engineering.

The challenges for AR are

  1. Design thin beam combiners using waveguides
  2. Eye box vs. field of view trade-off
  3. Eye tracking
  4. Chromatic aberrations
  5. Occlusions; difficulty: need to block real light

Only a few mm of physical display displacement results in a large change of the perceived virtual image

Monday, September 11, 2017


The latest issue of Science magazine has an article explaining how the retinotopic map is built during the development of the eye. The authors show that glial cells that ensheath axons relay cues from photoreceptors to induce the differentiation of the photoreceptor target field—the so-called lamina neurons. Thus, glia can play an instructive role in differentiation, helping to direct the spatiotemporal patterning of neurogenesis.

Science 01 Sep 2017: Vol. 357, Issue 6354, pp. 886–891, DOI: 10.1126/science.aan3174

Another recent article demonstrated that there is no retinotopic map further up in the visual system where object recognition takes place.

Science 18 Aug 2017: Vol. 357, Issue 6352, pp. 687-692, DOI: 10.1126/science.aan4800

Glia relay differentiation cues to coordinate neuronal development in Drosophila

Monday, August 21, 2017

biology of color

The 4 August issue of Science (Vol. 357, Issue 6350, eaan0221) has a valuable article on the biology of color describing the current state of the art in this interdisciplinary field of animal coloration. This article is important because in the past 20 years there has been significant progress in this field.
mantis shrimp

Thursday, August 17, 2017

Critical thinking in a changing world

Monday evening, Gioia Deucher, the new CEO of swissnex San Francisco on Pier 17, hosted a double event on critical thinking. The first event was only for ETH alumni and consisted of networking followed by a speech by ETH President Lino Guzzella and a general discussion. Prof. Guzzella noted that in recent years, students have changed and despite social media have become much nerdier and socially isolated. Consequently, the ETH has to change how it teaches.

As a professor of mechanical engineering, Guzzella does not expect any new breakthroughs in the physics for building mechanical equipment. What is more important for a mechanical engineer is to understand the context requiring a new machine and grasp the problem holistically and proposing a new approach.

The human genetic code has not changed over the ages and is still the same as for hunter gatherers. Critical thinking is essential, but it is hard to criticize oneself: we are dependent on a group that mutually criticizes and debates.

This autumn, the ETH is introducing significant changes. In teaching, the emphasis will be more on understanding and solving problems than on learning. Students will have the option for project-oriented study and more personal coaching with group study. In the study directions, the ETH is starting a new department of medicine, which will allow a proper medical study. Initially, the new department will only go until the bachelor level, after which students can transfer directly to a Swiss university with a medicine program or change to a more traditional ETH department like bioinformatics. As we live longer and longer, significant medical progress is necessary to maintain life quality into the old age.

When a question came about ETH's plans for massive open online courses (MOOC), Prof. Guzzella stated that they go counter the new direction to foster critical thinking and team work: students need physical proximity and a shared experience to become extraordinary people.

The public second event, which had unexpectedly high attendance, started with lightning talks and a panel discussion, followed by a discussion with the audience and finally a standing dinner with animated discussions and networking.

The speakers were Lino Guzzella, President of ETH Zurich and Professor for thermotronics; Gerd Folkers, Chair Science Studies and Critical Thinking Initiative at ETH and former Head of the Collegium Helveticum, a joint think-tank of ETH and University of Zurich; Hans Ulrich Gumbrecht, Professor in Literature in the Departments of Comparative Literature and of French & Italian at Stanford; Philippe Kahn, the CEO of Fullpower, the creative team behind the Sleeptracker IoT Smartbed technology platform and the MotionX Wearable Technology platform. The moderator was Chris Luebkeman, Arup Fellow and Global Director of Arup Foresight.

There was a consensus that to contribute to the wellness and progress of society, and it is indispensable to excel in critical thinking and bring about paradigm shifts. There is no point for a bright mind to just do repetitive intellectual tasks like at the Academy of Projectors. Critical thinking requires a fertile environment, therefore creating groups and projects is more important than promoting individual excellence.

Publications are a very bad metric. A paper needs the unpaid work of three reviewers and is expensive regarding social costs, yet 52% of publications are never cited and consequently have no value because they do not contribute to society.

Excellence in research requires freedom and money. Professors should not be told which research to conduct and should not waste time chasing grants. Science is for the good of society and society should fund research and tuition at universities (I never had to pay a penny of tuition for my diploma in mathematics and my doctorate in informatics). Critical thinking is what prevents the Lagado of Gulliver's third voyage: a habitat for scientists critically thinking in a changing world instead of an Academy of Projectors.

When Stanford wanted to introduce the option for STEM students to major or minor in literature, Prof. Gumbrecht was the strongest opponent. However, after the first year, he now realized that his best students had all come from STEM and he has become a strong advocate for the program.

speculative learning machine at the Academy of Projectors in Lagado

Thursday, July 6, 2017

Well-being in the San Francisco Bay Area

At the University of Pennsylvania’s Positive Psychology Center, Martin Seligman and more than 20 psychologists, physicians, and computer scientists in the World Well-Being Project used machine learning and natural language processing to sift through Twitter. They have been able to rank each of the 3235 U.S. counties according to well-being, depression, trust, and five personality traits.

For the Bay Area, the rankings are:

San Francisco
San Mateo
Santa Clara
Santa Cruz
Contra Costa

If you live in the U.S., you can check your county in their online map. For example, Kings County in New York ranks 448, while the District of Columbia ranks 49.

How is your well-being?

well-being ranks of Bay Area counties