Publications by authors named "John Vaughan"

Background: Abdominal adhesions are networks of fibrotic tissues that form between organs postoperatively. Current prophylactic strategies do not reproducibly prevent adhesive small bowel obstruction across the entire abdomen. Human placental-derived stem cells produce an anti-inflammatory secretome that has been applied to multiple fibrosing diseases.

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  • * A 2D convolutional neural network (CNN) was trained on synthesized data and tested on various datasets, achieving notable precision (85%) and recall (80%) in identifying motion issues.
  • * The model demonstrated excellent agreement with a radiologist's assessments (93%) and correlates strongly with an image quality metric, aiming to streamline the quality assessment process, especially in low-resource environments.
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Introduction: Abdominal adhesions represent a chronic postsurgical disease without reliable prophylaxis. Animal modeling has been a cornerstone of novel therapeutic development but has not produced reliable clinical therapies for prevention of adhesive small bowel obstruction. The purpose of this scoping review is to analyze animal models for abdominal adhesion generation by key considerations of external validity (i.

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Background: Very low-field MR has emerged as a promising complementary device to high-field MRI scanners, offering several advantages. One of the key benefits is that very low-field scanners are generally more portable and affordable to purchase and maintain, making them an attractive option for medical facilities looking to reduce costs. Very low-field MRI systems also have lower RF power deposition, making them safer and less likely to cause tissue heating or other safety concerns.

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  • A study developed a new rat model to investigate abdominal adhesions, a common surgical issue, and tested various treatments including human placental stem cells (hPSC).
  • Forty-four male Sprague-Dawley rats were used; the study involved creating adhesions and applying different treatments, including a control group and various experimental therapies over a 14-day period.
  • Results showed that treatments with hPSC and its secretome significantly reduced the severity of abdominal adhesions compared to the control group, indicating potential for new therapeutic approaches.
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Silver has long been recognized for its potent antimicrobial properties, but achieving a slow and longer-term delivery of silver ions presents significant challenges. Previous efforts to control silver ion dosages have struggled to sustain release for extended periods in biomimetic environments, especially in the presence of complex proteins. This challenge is underscored by the absence of technology for sustaining antimicrobial activity, especially in the context of orthopedic implants where long-term efficacy, extending beyond 7 days, is essential.

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This study presents a tool that introduces the fundamental concepts of magnetic resonance (MR) by integrating related science, technology, engineering, arts, and mathematical (STEAM) topics in the form of games to improve the access to MR education.

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  • Magnetic Resonance Imaging (MRI) is essential for diagnosing Alzheimer's Disease (AD) but is often slow due to the need for expertise in optimizing imaging protocols, which affects its clinical value.
  • The study shows how a deep learning-based approach can enhance MRI efficiency by improving image quality and increasing imaging throughput by 1.94 times using an accelerated protocol known as the Gold Standard (GS) protocol.
  • The GS protocol is a significant part of comprehensive AD imaging, and the study also explores its potential for automating volumetric measurements of relevant brain structures related to AD diagnosis.
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  • This study introduces a new method for magnetic resonance thermometry, called MRFT, and compares its effectiveness with the established PRFS thermometry in measuring temperatures in bovine muscle.
  • The experiments utilized a 3 Tesla MRI system and involved using fluoroptic probes to assess temperature at various locations, from the center of a cooled muscle to the heated areas near deep brain stimulation leads.
  • Results showed that both MRFT and PRFS accurately predicted temperature changes with a strong correlation to probe measurements, indicating that MRFT is a viable technique for thermal mapping in medical applications.
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Presently, magnetic resonance imaging (MRI) magnets must deliver excellent magnetic field (B ) uniformity to achieve optimum image quality. Long magnets can satisfy the homogeneity requirements but require considerable superconducting material. These designs result in large, heavy, and costly systems that aggravate as field strength increases.

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Raw data, simulated and acquired phantom images, and quantitative longitudinal and transverse relaxation times (T/T) maps from two open-source Magnetic Resonance Imaging (MRI) pulse sequences are presented in this dataset along with corresponding ".seq" files, sequence implementation scripts, and reconstruction/analysis scripts [1]. Real MRI data were collected from a 3T Siemens Prisma Fit and a 1.

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Introduction: Globally, abdominal adhesions constitute a significant burden of morbidity and mortality. They represent the commonest complication of abdominal operations with a lifelong risk of multiple pathologies, including adhesive small bowel obstruction, female infertility, and chronic pain. Adhesions represent a problem of the entire abdomen, forming at the time of injury and progressing through multiple complex pathways.

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Purpose: The goals of this study include: (a) generating tailored magnetic resonance fingerprinting (TMRF) based non-synthetic imaging; (b) assessing the repeatability of TMRF and deep learning-based mapping of in vitro ISMRM/NIST phantom and in vivo brain data of healthy human subjects.

Methods: We have acquired qualitative images obtained from the vendor-supplied gold standard (GS), MRF (synthetic), and TMRF (non-synthetic) on one representative healthy human brain. We also acquired 30 datasets on the ISMRM/NIST phantom for the in vitro repeatability study on a GE Discovery 3T MR750w scanner using the TMRF sequence.

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Open-source pulse sequence programs offer an accessible and transparent approach to sequence development and deployment. However, a common framework for testing, documenting, and sharing open-source sequences is still needed to ensure sequence usability and repeatability. We propose and demonstrate such a framework by implementing two sequences, Inversion Recovery Spin Echo (IRSE) and Turbo Spin Echo (TSE), with PyPulseq, and testing them on a commercial 3 T scanner.

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Lack of ergonomic training and poor ergonomic habits during the operation leads to musculoskeletal pain and affects the surgeon's life outside of work. The objective of the study was to evaluate the severity of ergonomic hazards in the surgical profession across a wide range of surgical subspecialties. We conducted intraoperative observations using Rapid Entire Body Assessment (REBA) score system to identify ergonomic hazards.

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Purpose: Demonstrate ability to produce reasonable simulations of temperature using numerical models of the human body with a limited number of tissues.

Methods: For both a male and female human body model, numerical simulations were used to calculate temperature distributions in three different models of the same human body: the original model with 35 tissues for the male model and 76 tissues for the female model, a simplified model having only three tissues (muscle, fat, and lung), and a simplified model having six tissues (muscle, fat, lung, bone, brain, and skin).

Results: Although a three-tissue model gave reasonable specific absorption rate estimates in comparison to an original with many more tissues, because of tissue-specific thermal and physiological properties that do not affect specific absorption rate, such as rate of perfusion by blood, the three-tissue model did not provide temperature distributions similar to those of the original model.

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Antimicrobial silver (Ag) coatings on orthopaedic implants may reduce infection rates, but should not be to the detriment of regenerative cell populations, primarily mesenchymal stem/stromal cells (MSCs). We determined intramedullary silver release profiles in vivo, which were used to test relevant Ag concentrations on MSC function in vitro. We measured a rapid elution of Ag from intramedullary pins in a rat femoral implantation model, delivering a maximum potential concentration of 7.

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Fungal infections are becoming a global health problem. A major limiting factor for the development of antifungals is the high impermeability of the rigid and thick fungal cell wall. Compared to mammalian cells, fungal cells are more resilient to perforation due to the presence of this carbohydrate armor.

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We present the design and performance of an active stabilization system for attosecond pump-probe setups based on a Mach-Zehnder interferometer configuration. The system employs a CW laser propagating coaxially with the pump and probe beams in the interferometer. The stabilization is achieved with a standalone feedback controller that adjusts the length of one of its arms to maintain a constant relative phase between the CW beams.

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The role of MRI in diagnostics, prognostics, and discoveries in basic sciences has been well established. However, access to this life-saving technology is largely restricted to countries in upper-middle to high-income groups. In this article, we collate recent global MR scanner density data and group them into six geographical regions based on the WHO classification.

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Objectives/hypothesis: To evaluate the presence of postural-related strain and musculoskeletal discomfort, along with the level of ergonomics training and the availability of ergonomic equipment among otolaryngology surgeons.

Study Design: Intraoperative observations and survey study.

Methods: Using the Rapid Entire Body Assessment score system to identify ergonomic hazards, we conducted intraoperative observations assessing operating room personnel during different otolaryngological subspecialty procedures.

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  • * The study explored how pulsed stimuli—changes in visual and auditory inputs over time—impact the SC's response, revealing that they generate multiple peaks in activity, leading to higher overall responses compared to non-pulsed stimuli.
  • * The findings suggest that the timing and alignment of individual sensory inputs (unisensory) play a crucial role in determining how robust the multisensory responses are, rather than just the nature of the stimuli themselves.
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  • A coupler is essential for monitoring forward and reflected RF power in real-time RF systems, with directivity being crucial for accurate measurements.
  • The paper presents a microstrip coupler with a tunable circuit designed to enhance directivity by adjusting the phase and amplitude of the coupled RF signal, effectively canceling leakage at the reflection port.
  • Experimental results demonstrate that this compact coupler can handle high power (up to 1 kW) and achieve directivities over 40 dB across specific frequency bands suitable for MRI applications.
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Higher magnetic field strength in magnetic resonance imaging (MRI) systems offers higher signal-to-noise ratio (SNR), contrast, and spatial resolution in MR images. However, the wavelength in ultra-high fields (7 tesla and beyond) becomes shorter than the human body at the Larmor frequency with increasing static magnetic field (B) of MRI system. At short wavelengths, interference effect appears resulting in non- uniformity of the RF magnetic near-field (B) over the subject and MR images may have spatially anomalous contrast.

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Magnetic resonance imaging (MRI) is a widely used nonionizing and noninvasive diagnostic instrument to produce detailed images of the human body. The radio-frequency (RF) coil is an essential part of MRI hardware as an RF front-end. RF coils transmit RF energy to the subject and receive the returning MR signal.

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