The drug discovery process currently employed in the pharmaceutical industry typically requires about 10 years and $2–3 billion to deliver one new drug. This is both too expensive and too slow, especially in emergencies like the COVID-19 pandemic. In silico methodologies need to be improved both to select better lead compounds, so as to improve the efficiency of later stages in the drug discovery protocol, and to identify those lead compounds more quickly. No known methodological approach can deliver this combination of higher quality and speed. Here, we describe an Integrated Modeling PipEline for COVID Cure by Assessing Better LEads (IMPECCABLE) that employs multiple methodological innovations to overcome this fundamental limitation. We also describe the computational framework that we have developed to support these innovations at scale, and characterize the performance of this framework in terms of throughput, peak performance, and scientific results. We show that individual workflow components deliver 100 × to 1000 × improvement over traditional methods, and that the integration of methods, supported by scalable infrastructure, speeds up drug discovery by orders of magnitudes. IMPECCABLE has screened ∼ 1011 ligands and has been used to discover a promising drug candidate. These capabilities have been used by the US DOE National Virtual Biotechnology Laboratory and the EU Centre of Excellence in Computational Biomedicine.

A weakness in the wall of a cerebral artery causing a dilation or ballooning of the blood vessel is known as a cerebral aneurysm. Optimal treatment requires fast and accurate diagnosis of the aneurysm. HemeLB is a fluid dynamics solver for complex geometries developed to provide neurosurgeons with information related to the flow of blood in and around aneurysms. On a cost efficient platform, HemeLB could be employed in hospitals to provide surgeons with the simulation results in real-time. In this work, we developed an improved version of HemeLB for GPU implementation and result visualization. A visualization platform for smooth interaction with end users is also presented. Finally, a comprehensive evaluation of this implementation is reported. The results demonstrate that the proposed implementation achieves a maximum performance of 15,168,964 site updates per second, and is capable of speeding up HemeLB for deployment in hospitals and clinical investigations.

We describe our Multiscale Computing Patterns software for High Performance Multiscale Computing. Following a short review of Multiscale Computing Patterns, this paper introduces the Multiscale Computing Patterns Software, which consists of description, optimisation and execution components. First, the description component translates the task graph, representing a multiscale simulation, to a particular type of multiscale computing pattern. Second, the optimisation component selects and applies algorithms to find the most suitable mapping between submodels and available HPC resources. Third, the execution component which a middleware layer maps submodels to the number and type of physical resources based on the suggestions emanating from the optimisation part together with infrastructure-specific metrics such as queueing time and resource availability. The main purpose of the Multiscale Computing Patterns software is to leverage the Multiscale Computing Patterns to simplify and automate the execution of complex multiscale simulations on high performance computers, and to provide both application-specific and pattern-specific performance optimisation. We test the performance and the resource usage for three multiscale models, which are expressed in terms of two Multiscale Computing Patterns. In doing so, we demonstrate how the software automates resource selection and load balancing, and delivers performance benefits from both the end-user and the HPC system level perspectives.

The efficacy of drug treatments depends on how tightly small molecules bind to their target proteins. Quantifying the strength of these interactions (the so called `binding affinity') is a grand challenge of computational chemistry, surmounting which could revolutionize drug design and provide the platform for patient specific medicine. Recently, evidence from blind challenge predictions and retrospective validation studies has suggested that molecular dynamics (MD) can now achieve useful predictive accuracy ( 1 kcal/mol) This accuracy is sufficient to greatly accelerate hit to lead and lead optimization. To translate these advances in predictive accuracy so as to impact clinical and/or industrial decision making requires that binding free energy results must be turned around on reduced timescales without loss of accuracy. This demands advances in algorithms, scalable software systems, and intelligent and efficient utilization of supercomputing resources. This work is motivated by the real world problem of providing insight from drug candidate data on a time scale that is as short as possible. Specifically, we reproduce results from a collaborative project between UCL and GlaxoSmithKline to study a congeneric series of drug candidates binding to the BRD4 protein - inhibitors of which have shown promising preclinical efficacy in pathologies ranging from cancer to inflammation. We demonstrate the use of a framework called HTBAC, designed to support the aforementioned requirements of accurate and rapid drug binding affinity calculations. HTBAC facilitates the execution of the numbers of simulations while supporting the adaptive execution of algorithms. Furthermore, HTBAC enables the selection of simulation parameters during runtime which can, in principle, optimize the use of computational resources whilst producing results within a target uncertainty.

The efficacy of drug treatments depends on how tightly small molecules bind to their target proteins. The rapid and accurate quantification of the strength of these interactions (as measured by 'binding affinity') is a grand challenge of computational chemistry, surmounting which could revolutionize drug design and provide the platform for patient specific medicine. Recent evidence suggests that molecular dynamics (MD) can achieve useful predictive accuracy (? 1 kcal/mol). For this predictive accuracy to impact clinical decision making, binding free energy results must be turned around rapidly and without loss of accuracy. This demands advances in algorithms, scalable software systems, and efficient utilization of supercomputing resources. We introduce a framework called HTBAC, designed to support accurate and scalable drug binding affinity calculations, while marshaling large simulation campaigns. We show that HTBAC supports the specification and execution of adaptive free-energy protocols at scale and with minimal overheads on NCSA Blue Waters. We validate the results obtained and show how adaptivity can be used to improve accuracy while reducing resource consumption of TIES, a widely used free-energy protocol.

BACKGROUND: Resistance to chemotherapy and molecularly targeted therapies is a major factor in limiting the effectiveness of cancer treatment. In many cases, resistance can be linked to genetic changes in target proteins, either pre-existing or evolutionarily selected during treatment. Key to overcoming this challenge is an understanding of the molecular determinants of drug binding. Using multi-stage pipelines of molecular simulations we can gain insights into the binding free energy and the residence time of a ligand, which can inform both stratified and personal treatment regimes and drug development. To support the scalable, adaptive and automated calculation of the binding free energy on high-performance computing resources, we introduce the High-throughput Binding Affinity Calculator (HTBAC). HTBAC uses a building block approach in order to attain both workflow flexibility and performance. RESULTS: We demonstrate close to perfect weak scaling to hundreds of concurrent multi-stage binding affinity calculation pipelines. This permits a rapid time-to-solution that is essentially invariant of the calculation protocol, size of candidate ligands and number of ensemble simulations. CONCLUSIONS: As such, HTBAC advances the state of the art of binding affinity calculations and protocols. HTBAC provides the platform to enable scientists to study a wide range of cancer drugs and candidate ligands in order to support personalized clinical decision making based on genome sequencing and drug discovery.

Proteolytic processing of Gag and Gag-Pol polyproteins by the viral protease (PR) is crucial for the production of infectious HIV-1, and inhibitors of the viral PR are an integral part of current antiretroviral therapy. The process has several layers of complexity (multiple cleavage sites and substrates; multiple enzyme forms; PR auto-processing), which calls for a systems level approach to identify key vulnerabilities and optimal treatment strategies. Here we present the first full reaction kinetics model of proteolytic processing by HIV-1 PR, taking into account all canonical cleavage sites within Gag and Gag-Pol, intermediate products and enzyme forms, enzyme dimerization, the initial auto-cleavage of full-length Gag-Pol as well as self-cleavage of PR. The model allows us to identify the rate limiting step of virion maturation and the parameters with the strongest effect on maturation kinetics. Using the modelling framework, we predict interactions and compensatory potential between individual cleavage rates and drugs, characterize the time course of the process, explain the steep dose response curves associated with PR inhibitors and gain new insights into drug action. While the results of the model are subject to limitations arising from the simplifying assumptions used and from the uncertainties in the parameter estimates, the developed framework provides an extendable open-access platform to incorporate new data and hypotheses in the future.

Grid middleware and the computational infrastructure that sits beneath it still present a steep learning curve for ordinary scientific end users. Subsequent to the development of grid computing has been the rise of cloud computing, further complicating the process of using third-party computation to execute biomedical simulations. In this paper, we present the Application Hosting Environment 3.0, which virtualizes grid applications and exposes the functionalities through a simple and concise RESTful web service interface. This simple interface allows grid deployed applications to be accessed through simple HTTP calls, meaning that users can easily integrate such applications into more complicated workflow. We also describe how AHE 3.0 is being integrated into a wider biomedical simulation infrastructure, to allow users to seamlessly access cloud and high performance computing resources.

Today scientists and engineers are commonly faced with the challenge of modelling, predicting and controlling multiscale systems which cross scientific disciplines and where several processes acting at different scales coexist and interact. Such multidisciplinary multiscale models, when simulated in three dimensions, require large scale or even extreme scale computing capabilities. The MAPPER project is developing computational strategies, software and services to enable distributed multiscale simulations across disciplines, exploiting existing and evolving e-Infrastructure. The resulting multi-tiered software infrastructure, which we present in this paper, has as its aim the provision of a persistent, stable infrastructure that will support any computational scientist wishing to perform distributed, multiscale simulations.

One major problem faced by end-users and administrators of computational grid environments arise in connection with the usability of the security mechanisms usually deployed in these environments, in particular identity management. Many of the existing computational grid environments use Public Key Infrastructure (PKI) and X.509 digital certificates as a corner stone for their security architectures. However, security solutions based on PKI have to be usable to be effective otherwise they will not provide the intended protection. This paper presents the Audited Credential Delegation (ACD), a user-centric security identity management solution that accommodates users and resource providers security requirements including authentication, authorisation and auditing security goals from the design level. The proposed architecture removes any association between users and digital certificates, which is the source of the grid usability problem, while addressing resource providers concerns with regards to accountability. A prototype of this architecture has been implemented in Java and Web Services technologies using the recommendations of the Open Web Application Security consortium (OWASP) for developing secure software. It is currently being tested on TeraGrid, NGS and DEISA grid infrastructures and a detailed usability study is underway.

E-health makes use of information and communication methods and the latest e-research tools to support the understanding of body functions. E-scientists in this field take already advantage of one single infrastructure to perform computationally-intensive investigations of the human body that tend to consider each of the constituent parts separately without taking into account the multiple important interactions between them. But these important interactions imply an increasing complexity of applications that embrace multiple physical models (i.e. multi-physics) and consider a larger range of scales (i.e. multi-scale) thus creating a steadily growing demand for interoperable infrastructures that allow for new innovative application types of jointly using different infrastructures for one application. But interoperable infrastructures are still not seamlessly provided and we argue that this is due to the absence of a realistically implementable infrastructure interoperability reference model that is based on lessons learned from e-science usage. Therefore, the goal of this paper is to explore the potential of using multiple infrastructures for one scientific goal with a particular focus on e-health. Since e-scientists gain more interest in using multiple infrastructures there is a clear demand for interoperability between them to enable a use with one e-research tool. The paper highlights work in the context of an e-Health blood flow application while the reference model is applicable to other e-science applications as well.

Large scale supercomputing applications typically run on clusters using vendor message passing libraries, limiting the application to the availability of memory and CPU resources on that single machine. The ability to run inter-cluster parallel code is attractive since it allows the consolidation of multiple large scale resources for computational simulations not possible on a single machine, and it also allows the conglomeration of small subsets of CPU cores for rapid turnaround, for example, in the case of high-availability computing. MPIg is a grid-enabled implementation of the Message Passing Interface (MPI), extending the MPICH implementation of MPI to use Globus Toolkit services such as resource allocation and authentication. To achieve co-availability of resources, HARC, the Highly-Available Resource Co-allocator, is used. Here we examine two applications using MPIg: LAMMPS (Large-scale Atomic/ Molecular Massively Parallel Simulator), is used with a replica exchange molecular dynamics approach to enhance binding affinity calculations in HIV drug research, and HemeLB, which is a lattice-Boltzmann solver designed to address fluid flow in geometries such as the human cerebral vascular system. The cross-site scalability of both these applications is tested and compared to single-machine performance. In HemeLB, communication costs are hidden by effectively overlapping non-blocking communication with computation, essentially scaling linearly across multiple sites, and LAMMPS scales almost as well when run between two significantly geographically separated sites as it does at a single site.

The ability to use a visualisation tool to steer large simulations provides innovative and novel usage scenarios, e.g. the ability to use new algorithms for the computation of free energy profiles along a nanopore [1]. However, we find that the performance of interactive simulations is sensitive to the quality of service of the network with variable latency and packet loss in particular having a detrimental effect. The use of dedicated networks (provisioned in this case as a circuit-switched, point-to-point optical lightpath or lambda) can lead to significant (50% or more) performance enhancement. When running on say 128 or 256 processors of a high-end supercomputer this saving has a significant value. We perform experiments to understand the impact of network characteristics on the performance of a large parallel classical molecular dynamics simulation when coupled interactively to a remote visualisation tool. This paper discusses the experiments performed and presents the results from the systematic studies.

While great strides have been made in the field of grid middleware technology, difficulties deploying and configuring current grid middleware technologies from an end user perspective have led to many of the people who would benefit most from the technology, namely application scientists, to avoid using it. In response to this we have developed the Application Hosting Environment (AHE), a lightweight, easily deployable environment designed to simplify the way the scientist interacts with the grid. The AHE builds a layer of middleware on top of existing technologies such as Globus, abstracting the details of the particular underlying grid middleware in use. The functionality of the AHE is exposed as web services using the WSRF::Lite toolkit; the user interacts with these services to launch and monitor applications. The resulting system provides a great deal of flexibility, allowing clients to be developed for a range of devices from PDAs to desktop machines, and command line clients which can be scripted to produce complicated application workflows.

SPICE aims to understand the vital process of translocation of biomolecules across protein pores by computing the free energy profile of the translocating biomolecule along the vertical axis of the pore. Without significant advances at the algorithmic, computing and analysis levels, understanding problems of this size and complexity will remain beyond the scope of computational science for the foreseeable future. A novel algorithmic advance is provided by a combination of Steered Molecular Dynamics and Jarzynski’s Equation (SMD-JE); Grid computing provides the required new computing paradigm as well as facilitating the adoption of new analytical approaches. SPICE uses sophisticated grid infrastructure to couple distributed high performance simulations, visualization and instruments used in the analysis to the same framework. We describe how we utilize the resources of a federated trans-Atlantic Grid to use SMD-JE to enhance our understanding of the translocation phenomenon in ways that have not been possible until now.