Publications by authors named "Marc Fischer"

We used polymerase chain reaction (PCR) to identify bacterial infections in culture-negative pleural fluid specimens from Alaska Native children hospitalized with empyema. PCR identified ≥1 organism in 11 (79%) of 14 specimens. Streptococcus pneumoniae serotype 3 was detected in six specimens; all six participants had received 13-valent pneumococcal conjugate vaccine.

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Respiratory syncytial virus (RSV) is a leading cause of hospitalization among young children. Historically, American Indian and Alaska Native (AI/AN) children have experienced high rates of RSV-associated hospitalization. In August 2023, a preventive monoclonal antibody (nirsevimab) was recommended for all infants aged <8 months (born during or entering their first RSV season) and for children aged 8-19 months (entering their second RSV season) who have increased risk for severe RSV illness, including all AI/AN children.

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We evaluated factors associated with the presence of hepatitis A virus antibodies 23 years after initiating vaccination at ages 6-15 months. Among 67 participants, 86% (42/49) of those vaccinated at ages 12-15 months and 61% (11/18) of those vaccinated at 6 months remained seropositive at 23 years. Lack of maternal antibodies at enrollment and higher initial vaccine response were independently associated with higher antibody concentrations at 23 years.

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Background:  Microsurgical breast reconstruction using abdominal tissue is a complex procedure, in part, due to variable vascular/perforator anatomy. Preoperative computed tomography angiography (CTA) has mitigated this challenge to some degree; yet it continues to pose certain challenges. The ability to map perforators with Mixed Reality has been demonstrated in case studies, but its accuracy has not been studied intraoperatively.

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Introduction: New strategies and methods are needed to ensure that new generations can train and acquire surgical skills in a safe environment.

Materials And Methods: From January 2020 to October 2020, we performed a single centre, prospective observational cohort study. 19 participants (15 students, 4 residents) enrolled and 16 participants (13 students, 3 residents) successfully completed the curriculum.

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Article Synopsis
  • A new technique uses augmented reality on smartphones and tablets to help surgeons access and review 3D models of perforator anatomy for breast reconstruction on the go.
  • This method specifically helps address the challenges of the deep inferior epigastric artery's variable anatomy, offering a more efficient alternative to prior methods that required dependency on others for imaging data.
  • By converting CT angiography data into a user-friendly format compatible with Apple devices, surgeons can easily explore and share patient-specific anatomical models in both object and augmented reality modes, enhancing understanding and communication in clinical practice.
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Preoperative vascular imaging has become standard practice in the planning of microsurgical breast reconstruction. Currently, translating perforator locations from radiological findings to a patient's abdomen is often not easy or intuitive. Techniques using three-dimensional printing or patient-specific guides have been introduced to superimpose anatomy onto the abdomen for reference.

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Plastic surgeons routinely use 3D-models in their clinical practice, from 3D-photography and surface imaging to 3D-segmentations from radiological scans. However, these models continue to be viewed on flattened 2D screens that do not enable an intuitive understanding of 3D-relationships and cause challenges regarding collaboration with colleagues. The Metaverse has been proposed as a new age of applications building on modern Mixed Reality headset technology that allows remote collaboration on virtual 3D-models in a shared physical-virtual space in real-time.

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New process developments linked to Power to X (energy storage or energy conversion to another form of energy) require tools to perform process monitoring. The main gases involved in these types of processes are H, CO, CH, and CO. Because of the non-selectivity of the sensors, a multi-sensor matrix has been built in this work based on commercial sensors having very different transduction principles, and, therefore, providing richer information.

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The hydraulic conveying of glass beads is studied in a horizontal tube. At low flow rates, plugs can be observed moving across the tube, whereas pseudoplugs can be seen at higher flow rates. A statistical analysis of the plugs' and pseudoplugs' velocities and the plugs' lengths observed is conducted.

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Background: Persistent human papillomavirus (HPV) infection can cause anogenital and oropharyngeal cancers. Many HPV infections and HPV-associated cancers are vaccine-preventable. Studies suggest long-term persistence of vaccine-induced antibodies.

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Preoperative computed tomographic angiography is increasingly performed before perforator flap-based reconstruction. However, radiologic two-dimensional thin slices do not allow for intuitive interpretation and translation to intraoperative findings. Three-dimensional volume rendering has been used to alleviate the need for mental two-dimensional to three-dimensional abstraction.

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Otitis media-associated outpatient visits among American Indians/Alaska Natives children <5 years old decreased by 52% (100 to 48 per 100 children per year) from 2003 to 2019. Otitis media visits decreased by another 50% from 2019 to 2020, but rebounded between 2020 and 2021 back to a rate similar to 2019.

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Neural networks pre-trained on a self-supervision scheme have become the standard when operating in data rich environments with scarce annotations. As such, fine-tuning a model to a downstream task in a parameter-efficient but effective way, e.g.

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Background: Adults aged ≥65 years, adults with certain underlying medical conditions, and persons experiencing homelessness are at increased risk for invasive pneumococcal disease (IPD). Two new pneumococcal conjugate vaccines, 15-valent pneumococcal conjugate vaccine (PCV15) and 20-valent pneumococcal conjugate vaccine (PCV20), were recently approved for use in US adults. We describe the epidemiology of IPD among Alaska adults and estimate the proportion of IPD cases potentially preventable by new vaccines.

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This paper investigates the accuracy of Augmented Reality (AR) technologies, particularly commercially available optical see-through displays, in depicting virtual content inside the human body for surgical planning. Their inherent limitations result in inaccuracies in perceived object positioning. We examine how occlusion, specifically with opaque surfaces, affects perceived depth of virtual objects at arm's length working distances.

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In this work, we propose a processing pipeline for the extraction and identification of meaningful radiomics biomarkers in skeletal muscle tissue as displayed using Dixon-weighted MRI. Diverse and robust radiomics features can be identified that may be of aid in the accurate quantification e.g.

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Article Synopsis
  • The study examines patients in Alaska with invasive pneumococcal disease (IPD) who also tested positive for SARS-CoV-2 between January 2020 and December 2021, finding 20% of IPD patients had a concurrent COVID-19 infection.
  • No significant differences were found in demographics or health conditions between IPD patients with and without SARS-CoV-2; however, a higher mortality rate was observed in those with both infections (16% vs. 4%).
  • The research underscores the importance of vaccination for pneumococcal disease and COVID-19, particularly in vulnerable groups such as those experiencing homelessness.
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Background: Autologous breast reconstruction yields improved long-term aesthetic results but requires increased resources of practitioners and hospital systems. Innovations in radiographic imaging have been increasingly used to improve the efficiency and success of free flap harvest. Augmented reality affords the opportunity to superimpose relevant imaging on a surgeon's native field of view, potentially facilitating dissection of anatomically variable structures.

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Objectives: The UK Biobank (UKBB) and German National Cohort (NAKO) are among the largest cohort studies, capturing a wide range of health-related data from the general population, including comprehensive magnetic resonance imaging (MRI) examinations. The purpose of this study was to demonstrate how MRI data from these large-scale studies can be jointly analyzed and to derive comprehensive quantitative image-based phenotypes across the general adult population.

Materials And Methods: Image-derived features of abdominal organs (volumes of liver, spleen, kidneys, and pancreas; volumes of kidney hilum adipose tissue; and fat fractions of liver and pancreas) were extracted from T1-weighted Dixon MRI data of 17,996 participants of UKBB and NAKO based on quality-controlled deep learning generated organ segmentations.

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Medical image segmentation has seen significant progress through the use of supervised deep learning. Hereby, large annotated datasets were employed to reliably segment anatomical structures. To reduce the requirement for annotated training data, self-supervised pre-training strategies on non-annotated data were designed.

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Background: West Nile virus (WNV) is the leading cause of mosquito-borne illness in the continental USA. WNV occurrence has high spatiotemporal variation, and current approaches to targeted control of the virus are limited, making forecasting a public health priority. However, little research has been done to compare strengths and weaknesses of WNV disease forecasting approaches on the national scale.

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Chikungunya virus, a mosquito-borne alphavirus, causes acute febrile illness with polyarthralgia. Groups at risk for severe disease include neonates, people with underlying medical conditions, and those aged ≥ 65 years. Several chikungunya vaccines are in late clinical development with licensure expected in the United States during 2023.

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This work aims to leverage medical augmented reality (AR) technology to counter the shortage of medical experts in low-resource environments. We present a complete and cross-platform proof-of-concept AR system that enables remote users to teach and train medical procedures without expensive medical equipment or external sensors. By seeing the 3D viewpoint and head movements of the teacher, the student can follow the teacher's actions on the real patient.

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