In previous blog post, we introduced the idea of Bayesian optimization and its application in finding the lowest energy conformation of given molecule[1]. Here, we extend this approach to incorporate the knowledge of correlated torsion and accelerate the search.
Continue readingCategory Archives: Group Meetings
On the Virtues of the Command Line
Wind the clock back about 50 years, and you would have found the DSKY interface—with a display (DS) and keyboard (KY)—quite familiar. It was frontend to the guidance computer used on the Apollo missions, that ultimately allowed Neil Armstrong to utter that celebrated, “One small step for [a] man, one giant leap for mankind.” The device effectively used a command line.
Continue readingFilm review: Back to the lab
Background:
Interdisciplinary projects are in fashion. Nowadays, most of the top universities in the world offer “interdisciplinary” doctorate programs. It seems that becoming a specialist in a particular field is not enough to progress in science. Now, students must prove their ability to understand and be proficient in different areas. Why study only Chemistry if you can combine it with Statistics, Programming and Biology? The more tools and concepts you can play with the better.
Continue readingDimensions: The Mathematics of Symmetry and Space
Update: The exhibition was Highly Commended in Oxford’s The Vice-Chancellor’s Public Engagement with Research Awards 2019! [Link]
As part of outreach efforts, I have been involved with the exhibition “Dimensions: The Mathematics of Symmetry and Space” at the Ashmolean Museum. This exhibition is a great opportunity to explore a selection of the Ashmolean’s impressive collection from a mathematical (but very accessible) point of view.
Continue readingProperty based testing in Python with Hypothesis : how to break your own code before someone else does
Traceback (most recent call last):
ZeroDivisionError: integer division or modulo by 0We’ve all been there. You’ve written your code, tested it out on some toy data and then when you make the move to the real data, there was something you didn’t expect.
Maybe some samples have been truncated to zero. Maybe the input arrays are the wrong shape. Suddenly your code comes crashing down around you, and you’re left thinking: well how could I have known that was going to happen? I can’t test everything
Continue readingMagnetotaxis: A Bacterial Superpower
The idea of bacterial superpowers is perhaps most associated with superbugs: the terrifying, drug-resistant bacterial strains that appear ever more frequently in news reports. While the notion of a world where antibiotics no longer work is chilling, this blog post will focus on a more positive aspect of the bacterial domain.
One of the more “niche” bacterial superpowers is magnetotaxis: the ability of certain bacteria to align their motion to the Earth’s magnetic field. This phenomenon was first reported in 1963 by Salvatore Bellini in the University of Pavia. While observing bog sediment under the microscope, he noticed a set of bacteria orienting themselves in the same direction: towards the Earth’s magnetic North pole. He dubbed these gram-negative bacteria “magnetosensitive”, or “batteri magnetosensibili”, but the discovery went largely unnoticed by the international scientific community [1]. The name “magnetotactic bacteria” (MTB) was introduced about a decade later, when Richard Blakemore reported the same phenomenon for bacteria found in marine sediments [2]. Through transmission electron microscopy, Blakemore was also able to capture the cellular feature that gives MTBs their unusual abilities: a rod-like structure of membrane-bound, iron-rich inorganic crystals, called magnetosomes. Later it was revealed that this structure is supported by a dedicated cytoskeletal system, which keeps it rod-shaped and prevents the aggregation of magnetosomes [4]. Magnetotaxis then results from the combination of the passive alignment of the cell to the Earth’s magnetic field, and flagellar motion. Continue reading
Making the most of your CPUs when using python
Over the last decade, single-threaded CPU performance has begun to plateau, whilst the number of logical cores has been increasing exponentially.
Like it or loathe it, for the last few years, python has featured as one of the top ten most popular languages [tiobe / PYPL]. That being said however, python has an issue which makes life harder for the user wanting to take advantage of this parallelism windfall. That issue is called the GIL (Global Interpreter Lock). The GIL can be thought of as the conch shell from Lord of the Flies. You have to hold the conch (GIL) for your thread to be computed. With only one conch, no matter how beautifully written and multithreaded your code, there will still only be one thread will be executed at any point in time.
Non-alcoholic fatty liver disease
In my new research project, I investigate Non-alcoholic fatty liver disease (NAFLD). This term describes a variety of conditions that are associated with fatty livers. While the early stages of this disease are not harmful, it can lead to cirrhosis (Cirrhosis is the scaring of liver tissue that prevents a liver to function properly). Ultimately, if a liver stops working it can be fatal unless treated, for example, with a liver transplant. NAFLD is the most common liver disease in developed countries and is expected to become the leading cause of liver transplant by 2020 [1].
The disease progresses in four stages: Continue reading
Graph-based Methods for Cheminformatics
In cheminformatics, there are many possible ways to encode chemical data represented by small molecules and proteins, such as SMILES, fingerprints, chemical descriptors etc. Recently, utilising graph-based methods for machine learning have become more prominent. In this post, we will explore why representing molecules as graphs is a natural and suitable encoding. Continue reading
Automated testing with doctest
One of the ways to make your code more robust to unexpected input is to develop with boundary cases in your mind. Test-driven code development begins with writing a set of unit tests for each class. These tests often includes normal and extreme use cases. Thanks to packages like doctest for Python, Mocha and Jasmine for Javascript etc., we can write and test codes with an easy format. In this blog post, I will present a short example of how to get started with doctest in Python. N.B. doctest is best suited for small tests with a few scripts. If you would like to run a system testing, look for some other packages!