Publications by authors named "Caleb Powell"

6 Publications

  • Page 1 of 1

Review of Irish patients meeting ST elevation criteria during the COVID-19 pandemic.

Open Heart 2021 08;8(2)

Department of Cardiology, Saint James's Hospital, Dublin, Ireland.

Introduction: The COVID-19 pandemic has seen the introduction of important public health measures to minimise the spread of the virus. We aim to identify the impact government restrictions and hospital-based infection control procedures on ST elevation myocardial infarction (STEMI) care during the COVID-19 pandemic.

Methods: Patients meeting ST elevation criteria and undergoing primary percutaneous coronary intervention from 27 March 2020, the day initial national lockdown measures were announced in Ireland, were included in the study. Patients presenting after the lockdown period, from 18 May to 31 June 2020, were also examined. Time from symptom onset to first medical contact (FMC), transfer time and time of wire cross was noted. Additionally, patient characteristics, left ventricular ejection fraction, mortality and biochemical parameters were documented. Outcomes and characteristics were compared against a control group of patients meeting ST elevation criteria during the month of January.

Results: A total of 42 patients presented with STEMI during the lockdown period. A significant increase in total ischaemic time (TIT) was noted versus controls (8.81 hours (±16.4) vs 2.99 hours (±1.39), p=0.03), with increases driven largely by delays in seeking FMC (7.13 hours (±16.4) vs 1.98 hours (±1.46), p=0.049). TIT remained significantly elevated during the postlockdown period (6.1 hours (±5.3), p=0.05), however, an improvement in patient delays was seen versus the control group (3.99 hours (±4.5), p=0.06). There was no difference seen in transfer times and door to wire cross time during lockdown, however, a significant increase in transfer times was seen postlockdown versus controls (1.81 hours (±1.0) vs 1.1 hours (±0.87), p=0.004).

Conclusion: A significant increase in TIT was seen during the lockdown period driven mainly by patient factors highlighting the significance of public health messages on public perception. Additionally, a significant delay in transfer times to our centre was seen postlockdown.
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August 2021

Performant barcode decoding for herbarium specimen images using vector-assisted region proposals (VARP).

Appl Plant Sci 2021 May 3;9(5). Epub 2021 Jun 3.

Department of Biology, Geology and Environmental Science University of Tennessee at Chattanooga 615 McCallie Avenue Chattanooga Tennessee 37403 USA.

Premise: The scale and associated costs of herbarium digitization make process automation appealing. One such process for many workflows is the association of specimen image files with barcode values stored with the specimen. Here, an innovation is presented that improves the speed and accuracy of decoding barcodes from specimen images.

Methods And Results: Geometric features common in barcodes are used to identify the regions of specimen images that are likely to contain a barcode. The proposed regions are then combined into a significantly reduced composite image that is decoded using traditional barcode reading libraries. Tested against existing solutions, this method demonstrated the highest success rate (96.5%) and the second fastest processing time (617 ms).

Conclusions: This method was developed to support a larger effort to automate specimen image post-processing in real-time, highlighting the importance of execution time. Although initially designed for herbarium digitization, this method may be useful for other high-resolution applications.
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May 2021

Effects of non-invasive respiratory support on gas exchange and outcomes in COVID-19 outside the ICU.

Respir Med 2021 Aug-Sep;185:106481. Epub 2021 May 25.

Department of Respiratory Medicine, Mater Misericordiae University Hospital, Dublin, Ireland.

Non-invasive respiratory support (NRS) outside of the ICU has played an important role in the management of COVID-19 pneumonia. There is little data to guide selection of NRS modality. We present outcomes of NRS outside the ICU and discuss the effects of NRS on gas exchange with implications for management.
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September 2021

Estimating herbarium specimen digitization rates: Accounting for human experience.

Appl Plant Sci 2021 Apr 30;9(4):e11415. Epub 2021 Apr 30.

Department of Biology, Geology, and Environmental Science University of Tennessee at Chattanooga 615 McCallie Avenue Chattanooga Tennessee 37403 USA.

Premise: Herbaria are invaluable sources for understanding the natural world, and in recent years there has been a concerted effort to digitize these collections. To organize such efforts, a method for estimating the necessary labor is desired. This work analyzes digitization productivity reports of 105 participants from eight herbaria, deriving generalized labor estimates that account for human experience.

Methods And Results: Individuals' rates of digitization were grouped based on cumulative time performing each task and then used to estimate a series of generalized labor projection models. In most cases, productivity was shown to improve with experience, suggesting longer technician retention can reduce labor requirements by 20%.

Conclusions: Using student labor is a common tactic for digitization efforts, and the resulting outreach exposes future professionals to natural history collections. However, overcoming the learning curve should be considered when estimating the labor necessary to digitize a collection.
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April 2021

Enabling automated herbarium sheet image post-processing using neural network models for color reference chart detection.

Appl Plant Sci 2020 Mar 2;8(3):e11331. Epub 2020 Mar 2.

Department of Computer Science and Engineering University of Tennessee at Chattanooga Chattanooga Tennessee USA.

Premise: Large-scale efforts to digitize herbaria have resulted in more than 18 million publicly available Plantae images on sites such as iDigBio. The automation of image post-processing will lead to time savings in the digitization of biological specimens, as well as improvements in data quality. Here, new and modified neural network methodologies were developed to automatically detect color reference charts (CRC), enabling the future automation of various post-processing tasks.

Methods And Results: We used 1000 herbarium specimen images from 52 herbaria to test our novel neural network model, ColorNet, which was developed to identify CRCs smaller than 4 cm, resulting in a 30% increase in accuracy over the performance of other state-of-the-art models such as Faster R-CNN. For larger CRCs, we propose modifications to Faster R-CNN to increase inference speed.

Conclusions: Our proposed neural networks detect a range of CRCs, which may enable the automation of post-processing tasks found in herbarium digitization workflows, such as image orientation or white balance correction.
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March 2020

A born-digital field-to-database solution for collections-based research using collNotes and collBook.

Appl Plant Sci 2019 Aug 23;7(8):e11284. Epub 2019 Aug 23.

Department of Biology Geology and Environmental Science University of Tennessee at Chattanooga 615 McCallie Avenue Chattanooga Tennessee 37403 USA.

Premise: The digitization of natural history collections includes transcribing specimen label data into standardized formats. Born-digital specimen data initially gathered in digital formats do not need to be transcribed, enabling their efficient integration into digitized collections. Modernizing field collection methods for born-digital workflows requires the development of new tools and processes.

Methods And Results: collNotes, a mobile application, was developed for Android and iOS to supplement traditional field journals. Designed for efficiency in the field, collNotes avoids redundant data entries and does not require cellular service. collBook, a companion desktop application, refines field notes into database-ready formats and produces specimen labels.

Conclusions: collNotes and collBook can be used in combination as a field-to-database solution for gathering born-digital voucher specimen data for plants and fungi. Both programs are open source and use common file types simplifying either program's integration into existing workflows.
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August 2019