µMatch: 3D shape correspondence for biological image data

Modern microscopy technologies allow imaging biological objects in 3D over a wide range of spatial and temporal scales, opening the way for a quantitative assessment of morphology. However, establishing a correspondence between objects to be compared, a first necessary step of most shape analysis workflows, remains challenging for soft-tissue objects without striking features allowing them to be landmarked. To address this issue, we introduce the μMatch 3D shape correspondence pipeline. μMatch implements a state-of-the-art correspondence algorithm initially developed for computer graphics and packages it in a streamlined pipeline including tools to carry out all steps from input data pre-processing to classical shape analysis routines. Importantly, μMatch does not require any landmarks on the object surface and establishes correspondence in a fully automated manner. Our open-source method is implemented in Python and can be used to process collections of objects described as triangular meshes. We quantitatively assess the validity of μMatch relying on a well-known benchmark dataset and further demonstrate its reliability by reproducing published results previously obtained through manual landmarking

Experimental demonstration of quantum effects in the operation of microscopic heat engines

The heat engine, a machine that extracts useful work from thermal sources, is one of the basic theoretical constructs and fundamental applications of classical thermodynamics. The classical description of a heat engine does not include coherence in its microscopic degrees of freedom. By contrast, a quantum heat engine might possess coherence between its internal states. Although the Carnot efficiency cannot be surpassed, and coherence can be performance degrading in certain conditions, it was recently predicted that even when using only thermal resources, internal coherence can enable a quantum heat engine to produce more power than any classical heat engine using the same resources. Such a power boost therefore constitutes a quantum thermodynamic signature. It has also been shown that the presence of coherence results in the thermodynamic equivalence of different quantum heat engine types, an effect with no classical counterpart. Microscopic heat machines have been recently implemented with trapped ions, and proposals for heat machines using superconducting circuits and optomechanics have been made. When operated with standard thermal baths, however, the machines implemented so far have not demonstrated any inherently quantum feature in their thermodynamic quantities. Here we implement two types of quantum heat engines by use of an ensemble of nitrogen-vacancy centres in diamond, and experimentally demonstrate both the coherence power boost and the equivalence of different heat-engine types. This constitutes the first observation of quantum thermodynamic signatures in heat machines

Experimental demonstration of quantum effects in the operation of microscopic heat engines

An account of experimental investigations into quantum effects in the operation of heat engines on the atomic scale. It consists of a description of the physical realisation of a heat engine implementation using the negative nitrogen vacancy centre in diamond. Theoretical results extending the idealised theory of quantum heat engines to account for experimental conditions are derived, along with results relating to the limit cycles of cyclic quantum heat engines. Finally the empirical existance of quantum thermodynamic signatures in the operation of microscopic heat engines are presented.</p

Experimental demonstration of quantum effects in the operation of microscopic heat engines

An account of experimental investigations into quantum effects in the operation of heat engines on the atomic scale. It consists of a description of the physical realisation of a heat engine implementation using the negative nitrogen vacancy centre in diamond. Theoretical results extending the idealised theory of quantum heat engines to account for experimental conditions are derived, along with results relating to the limit cycles of cyclic quantum heat engines. Finally the empirical existance of quantum thermodynamic signatures in the operation of microscopic heat engines are presented.</p

Bending the rules: Quantum effects in the operation of a microscopic heat engine in diamond

A classical heat engine that extracts work from thermal sources and which does not include coherence amongst its microscopic degrees of freedom is a fundamental concept of classical thermodynamics. In contrast, the internal states of a quantum heat engine (QHE) can exist in a coherent superposition of energy levels and a question of interest for such a QHE is whether it can exhibit thermodynamic behavior fundamentally different to that allowed in a classical engine. QHEs have recently been implemented using for example trapped ions [1]. However, experiments so far have not shown any non-classical features in their thermodynamic quantities. While the efficiency of a QHE is still bound by the Carnot limit, recent theoretical predictions show that coherence can boost its power output above the classically allowed limit for an engine using the same thermal resources [2]. Moreover, the presence of coherence was predicted to result in the equivalence of different QHE types in the limit of weak driving and short cycle duration.</p

An innovative non-invasive technique for subcutaneous tumour measurements.

INTRODUCTION:In oncological drug development, animal studies continue to play a central role in which the volume of subcutaneous tumours is monitored to assess the efficacy of new drugs. The tumour volume is estimated by taking the volume to be that of a regular spheroid with the same dimensions. However, this method is subjective, insufficiently traceable, and is subject to error in the accuracy of volume estimates as tumours are frequently irregular. METHODS & RESULTS:This paper reviews the standard technique for tumour volume assessment, calliper measurements, by conducting a statistical review of a large dataset consisting of 2,500 tumour volume measurements from 1,600 mice by multiple operators across 6 mouse strains and 20 tumour models. Additionally, we explore the impact of six different tumour morphologies on volume estimation and the detection of treatment effects using a computational tumour growth model. Finally, we propose an alternative method to callipers for estimating volume-BioVolumeTM, a 3D scanning technique. BioVolume simultaneously captures both stereo RGB (Red, Green and Blue) images from different light sources and infrared thermal images of the tumour in under a second. It then detects the tumour region automatically and estimates the tumour volume in under a minute. Furthermore, images can be processed in parallel within the cloud and so the time required to process multiple images is similar to that required for a single image. We present data of a pre-production unit test consisting of 297 scans from over 120 mice collected by four different operators. CONCLUSION:This work demonstrates that it is possible to record tumour measurements in a rapid minimally invasive, morphology-independent way, and with less human-bias compared to callipers, whilst also improving data traceability. Furthermore, the images collected by BioVolume may be useful, for example, as a source of biomarkers for animal welfare and secondary drug toxicity / efficacy