Experimental Testing and modeling of a Dual-Fired LiBr-H2O Absorption Chiller

An LiBr-H2O chiller was modified to utilize heat sources from natural gas combustion and/or from hot fluid. This was achieved by replacing the original gas-fired generator with a dual-fired generator. Steam was used as the hot fluid. The generator of the chiller can be powered by each source separately or both sources simultaneously. Experimental investigation was performed to obtain capacity and coefficient of performance (COP) of the original chiller and the modified chiller. During the experiments, the modified chiller was powered solely by steam, natural gas, or both. There was a significant increase in COP and capacity when steam was used as a heat source. The tests using natural gas resulted in performance similar to the original chiller. The experimental conditions were closely modeled by a numerical program

Does caffeine have an ergogenic effect on sports-specific agility in competitive male racquet sport players?

Purpose: Caffeine has been found to have an ergogenic effect on intermittent-sprinting performance and sport-specific agility (Stuart et al. 2005; Schneiker et al. 2006). However, racquet sports events (tennis, squash and badminton) which demand various repeated short-term high intensity exercise bouts have had little attention in this field. Caffeine can potentially reduce time to exhaustion, enhance concentration and dampen pain perception; all of which have been postulated to improve racquet sport performance (Hornery et al. 2007). The study aimed to investigate the effects of caffeine supplementation on the on-court movements used in racquet sports during a specific agility test. Methods: Following institutional ethical approval, eight competitive male racquet sports players were recruited (Age: 21.0 + 1.69, Stature: 1.75 + 0.05-cm, Mass: 72.9 + 7.9-kg). A randomised double-blind experiment was conducted which used two undistinguishable solutions (6-mg.kg-1); caffeine powder (CAF), and placebo (PL). Solutions were administered 60-min prior to testing in a counter-balanced design. Performance was measured by the time to completion (s) on two trials of the ‘four –corner’ agility test (Ooi et al. 2009) separated by a 2-min rest between bouts. Physiological variables measured included heart rate (HR), blood lactate (B.lac) and blood glucose (B.glu) which were recorded immediately at the end of each trial. Results: There was a significant difference (P < 0.05) in the time taken to complete the test between CAF (45.63 ± 3.66-s) and PL (47.57 ± 3.67-s) in the first trial (T1). There was also a significant (P < 0.05) increase in B.glu concentrations during T1 for CAF (CAF: 4.37 ± 0.12-mmol.l-1 vs. PL: 3.80 ± 0.33-mmol.l-1). The second trial (T2) showed a significant (P < 0.05) reduction in the time to complete the test with CAF (44.91 ± 4.78-s) compared to PL (46.70 ± 4.64-s). Furthermore, a significantly higher B.glu in the T2 was recorded with CAF (CAF: 4.69 + 0.30-mmol.l-1 vs. PL: 4.00 + 0.25-mmol.l-1). There were no significant differences in HR or B.lac between both the conditions during the two trials. Conclusions: A moderate dosage of caffeine, consumed 1-h before two bouts of a specific racquet agility test induced decreased time to completion during each trial compared to a placebo. Practically this could lead to more efficient on-court movements and improved positioning prior to a playing a shot. The increase in blood-bourne glucose levels following caffeine ingestion may have deferred fatigue within the glycolytic energy system allowing for increased performance

Quantitative 3D analysis of bone in hip osteoarthritis using clinical computed tomography.

OBJECTIVE: To assess the relationship between proximal femoral cortical bone thickness and radiological hip osteoarthritis using quantitative 3D analysis of clinical computed tomography (CT) data. METHODS: Image analysis was performed on clinical CT imaging data from 203 female volunteers with a technique called cortical bone mapping (CBM). Colour thickness maps were created for each proximal femur. Statistical parametric mapping was performed to identify statistically significant differences in cortical bone thickness that corresponded with the severity of radiological hip osteoarthritis. Kellgren and Lawrence (K&L) grade, minimum joint space width (JSW) and a novel CT-based osteophyte score were also blindly assessed from the CT data. RESULTS: For each increase in K&L grade, cortical thickness increased by up to 25 % in distinct areas of the superolateral femoral head-neck junction and superior subchondral bone plate. For increasing severity of CT osteophytes, the increase in cortical thickness was more circumferential, involving a wider portion of the head-neck junction, with up to a 7 % increase in cortical thickness per increment in score. Results were not significant for minimum JSW. CONCLUSIONS: These findings indicate that quantitative 3D analysis of the proximal femur can identify changes in cortical bone thickness relevant to structural hip osteoarthritis. KEY POINTS: • CT is being increasingly used to assess bony involvement in osteoarthritis • CBM provides accurate and reliable quantitative analysis of cortical bone thickness • Cortical bone is thicker at the superior femoral head-neck with worse osteoarthritis • Regions of increased thickness co-locate with impingement and osteophyte formation • Quantitative 3D bone analysis could enable clinical disease prediction and therapy development.TT acknowledges the support of an Evelyn Trust Clinical Training Fellowship award (RG65411). KP acknowledges support of an Arthritis Research UK Research Progression award (RG66087), and the Cambridge NIHR Biomedical Research Centre (RG64245). None of the funding sources had a role in study design, data handling, writing of the report, or decision to submit the paper for publication.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00330-015-4048-

NODEO: A Neural Ordinary Differential Equation Based Optimization Framework for Deformable Image Registration

Deformable image registration (DIR), aiming to find spatial correspondence between images, is one of the most critical problems in the domain of medical image analysis. In this paper, we present a novel, generic, and accurate diffeomorphic image registration framework that utilizes neural ordinary differential equations (NODEs). We model each voxel as a moving particle and consider the set of all voxels in a 3D image as a high-dimensional dynamical system whose trajectory determines the targeted deformation field. Our method leverages deep neural networks for their expressive power in modeling dynamical systems, and simultaneously optimizes for a dynamical system between the image pairs and the corresponding transformation. Our formulation allows various constraints to be imposed along the transformation to maintain desired regularities. Our experiment results show that our method outperforms the benchmarks under various metrics. Additionally, we demonstrate the feasibility to expand our framework to register multiple image sets using a unified form of transformation,which could possibly serve a wider range of applications

Big Data Needs Big Governance: Best Practices From Brain-CODE, the Ontario-Brain Institute’s Neuroinformatics Platform

The Ontario Brain Institute (OBI) has begun to catalyze scientific discovery in the field of neuroscience through its large-scale informatics platform, known as Brain-CODE. The platform supports the capture, storage, federation, sharing, and analysis of different data types across several brain disorders. Underlying the platform is a robust and scalable data governance structure which allows for the flexibility to advance scientific understanding, while protecting the privacy of research participants. Recognizing the value of an open science approach to enabling discovery, the governance structure was designed not only to support collaborative research programs, but also to support open science by making all data open and accessible in the future. OBI’s rigorous approach to data sharing maintains the accessibility of research data for big discoveries without compromising privacy and security. Taking a Privacy by Design approach to both data sharing and development of the platform has allowed OBI to establish some best practices related to large-scale data sharing within Canada. The aim of this report is to highlight these best practices and develop a key open resource which may be referenced during the development of similar open science initiatives

Quantitative Three-dimensional Assessment of Knee Joint Space Width from Weight-bearing CT.

Background Imaging of structural disease in osteoarthritis has traditionally relied on MRI and radiography. Joint space mapping (JSM) can be used to quantitatively map joint space width (JSW) in three dimensions from CT images. Purpose To demonstrate the reproducibility, repeatability, and feasibility of JSM of the knee using weight-bearing CT images. Materials and Methods Two convenience samples of weight-bearing CT images of left and right knees with radiographic Kellgren-Lawrence grades (KLGs) less than or equal to 2 were acquired from 2014 to 2018 and were analyzed retrospectively with JSM to deliver three-dimensional JSW maps. For reproducibility, images of three sets of knees were used for novice training, and then the JSM output was compared against an expert's assessment. JSM was also performed on 2-week follow-up images in the second cohort, yielding three-dimensional JSW difference maps for repeatability. Statistical parametric mapping was performed on all knee imaging data (KLG, 0-4) to show the feasibility of a surface-based analysis in three dimensions. Results Reproducibility (in 20 individuals; mean age, 58 years ± 7 [standard deviation]; mean body mass index, 28 kg/m2 ± 6; 14 women) and repeatability (in nine individuals; mean age, 53 years ± 6; mean body mass index, 26 kg/m2 ± 4; seven women) reached their lowest performance at a smallest detectable difference less than ±0.1 mm in the central medial tibiofemoral joint space for individuals without radiographically demonstrated disease. The average root mean square coefficient of variation was less than 5% across all groups. Statistical parametric mapping (33 individuals; mean age, 57 years ± 7; mean body mass index, 27 kg/m2 ± 6; 23 women) showed that the central-to-posterior medial joint space was significantly narrower by 0.5 mm for each incremental increase in the KLG (threshold P < .05). One knee (KLG, 2) demonstrated a baseline versus 24-month change in its three-dimensional JSW distribution that was beyond the smallest detectable difference across the lateral joint space. Conclusion Joint space mapping of the knee using weight-bearing CT images is feasible, demonstrating a relationship between the three-dimensional joint space width distribution and structural joint disease. It is reliably learned by novice users, can be personalized for disease phenotypes, and can be used to achieve a smallest detectable difference that is at least 50% smaller than that reported to be achieved at the highest performance level in radiography. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Roemer in this issue

Validating a novel deterministic privacy-preserving record linkage between administrative & clinical data: applications in stroke research

Introduction Research data combined with administrative data provides a robust resource capable of answering unique research questions. However, in cases where personal health data are encrypted, due to ethics requirements or institutional restrictions, traditional methods of deterministic and probabilistic record linkages are not feasible. Instead, privacy-preserving record linkages must be used to protect patients' personal data during data linkage. Objectives To determine the feasibility and validity of a deterministic privacy preserving data linkage protocol using homomorphically encrypted data. Methods Feasibility was measured by the number of records that successfully matched via direct identifiers. Validity was measured by the number of records that matched with multiple indirect identifiers. The threshold for feasibility and validity were both set at 95%. The datasets shared a single, direct identifier (health card number) and multiple indirect identifiers (sex and date of birth). Direct identifiers were encrypted in both datasets and then transferred to a third-party server capable of linking the encrypted identifiers without decrypting individual records. Once linked, the study team used indirect identifiers to verify the accuracy of the linkage in the final dataset. Results With a combination of manual and automated data transfer in a sample of 8,128 individuals, the privacy-preserving data linkage took 36 days to match to a population sample of over 3.2 million records. 99.9% of the records were successfully matched with direct identifiers, and 99.8% successfully matched with multiple indirect identifiers. We deemed the linkage both feasible and valid. Conclusions As combining administrative and research data becomes increasingly common, it is imperative to understand options for linking data when direct linkage is not feasible. The current linkage process ensured the privacy and security of patient data and improved data quality. While the initial implementations required significant computational and human resources, increased automation keeps the requirements within feasible bounds

nnResting state fMRI scanner instabilities revealed by longitud inal phantom scans in a multi-center study

Quality assurance (QA) is crucial in longitudinal and/or multi-site studies, which involve the collection of data from a group of subjects over time and/or at different locations. It is important to regularly monitor the performance of the scanners over time and at different locations to detect and control for intrinsic differences (e.g., due to manufacturers) and changes in scanner performance (e.g., due to gradual component aging, software and/or hardware upgrades, etc.). As part of the Ontario Neurodegenerative Disease Research Initiative (ONDRI) and the Canadian Biomarker Integration Network in Depression (CAN-BIND), QA phantom scans were conducted approximately monthly for three to four years at 13 sites across Canada with 3T research MRI scanners. QA parameters were calculated for each scan using the functional Biomarker Imaging Research Network\u27s (fBIRN) QA phantom and pipeline to capture between- and within-scanner variability. We also describe a QA protocol to measure the full-width-at-half-maximum (FWHM) of slice-wise point spread functions (PSF), used in conjunction with the fBIRN QA parameters. Variations in image resolution measured by the FWHM are a primary source of variance over time for many sites, as well as between sites and between manufacturers. We also identify an unexpected range of instabilities affecting individual slices in a number of scanners, which may amount to a substantial contribution of unexplained signal variance to their data. Finally, we identify a preliminary preprocessing approach to reduce this variance and/or alleviate the slice anomalies, and in a small human data set show that this change in preprocessing can have a significant impact on seed-based connectivity measurements for some individual subjects. We expect that other fMRI centres will find this approach to identifying and controlling scanner instabilities useful in similar studies

Designing and Implementing a Privacy Preserving Record Linkage Protocol

Introduction The Ontario Brain Institute has developed Brain-CODE, an informatics platform, to support the acquisition, storage, management and analysis of multi-modal data. The standardized research data within Brain-CODE spans several brain disorders, allowing for integrative analyses, while also providing the opportunity to leverage existing clinical administrative data holdings through external linkages. Objectives and Approach Within Ontario, the majority of individuals who access the healthcare system have a unique identifier, the Ontario Health Insurance Plan (OHIP) number. The OHIP number can facilitate linkages with administrative data holdings, such as those at the Institute for Clinical Evaluative Sciences (ICES). Given that OBI is not permitted under Ontario’s privacy legislation to hold OHIP numbers, identifiers for consented participants are encrypted using a public key mechanism upon entry into Brain-CODE, where the private key is inaccessible. To facilitate linkages involving OHIP numbers between Brain-CODE and ICES, Brain-CODE Link software was co-developed by members of the Indoc Consortium. Results Brain-CODE Link allows a deterministic linkage between encrypted identifiers (OHIP numbers), without revealing participant identity. The same homomorphic encryption algorithm applied to identifiers upon entry to Brain-CODE, is applied to relevant identifiers within ICES data holdings. Encrypted identifiers from Brain-CODE are securely transferred to ICES, where a comparison computation calculates differences between the encrypted sets. These differences are sent to a semi-trusted third party, who has no access to the original data, to decrypt the differences using the private key. A zero difference indicates a set of matching identifiers. One of the main challenges during testing and development of Brain-CODE Link was ensuring the software was capable of scaling to a population level, performing a large number of comparisons, in a computationally efficient manner. Conclusion/Implications Ongoing pilot projects within the areas of epilepsy, neurodevelopment disorders, and neurodegeneration will be the first examples of linkages between Brain-CODE and ICES. Brain-CODE Link has successfully performed several billion test comparisons, indicating its suitability to function as a scalable privacy preserving record linkage to support comprehensive analyses