Review of machine learning for optical imaging of burn wound severity assessment.

Significance: Over the past decade, machine learning (ML) algorithms have rapidly become much more widespread for numerous biomedical applications, including the diagnosis and categorization of disease and injury. Aim: Here, we seek to characterize the recent growth of ML techniques that use imaging data to classify burn wound severity and report on the accuracies of different approaches. Approach: To this end, we present a comprehensive literature review of preclinical and clinical studies using ML techniques to classify the severity of burn wounds. Results: The majority of these reports used digital color photographs as input data to the classification algorithms, but recently there has been an increasing prevalence of the use of ML approaches using input data from more advanced optical imaging modalities (e.g., multispectral and hyperspectral imaging, optical coherence tomography), in addition to multimodal techniques. The classification accuracy of the different methods is reported; it typically ranges from ∼70% to 90% relative to the current gold standard of clinical judgment. Conclusions: The field would benefit from systematic analysis of the effects of different input data modalities, training/testing sets, and ML classifiers on the reported accuracy. Despite this current limitation, ML-based algorithms show significant promise for assisting in objectively classifying burn wound severity.

Assessing Trends in Supply and Demand for Pediatric Surgery Training.

OBJECTIVE: This study assessed the supply and demand for Pediatric Surgery training in the U.S. from 2008 to 2022. We hypothesized that in the Pediatric Surgery Match: match rates would increase over time; U.S. MD Graduates would have higher match rates than non-U.S. MD Graduates; and fewer applicants would match at one of their top fellowship choices. DESIGN: This was a retrospective cohort study of Pediatric Surgery Match applicants (2008-2022). Cochran-Armitage tests elucidated temporal trends and chi square tests compared outcomes by applicant archetype. SETTING: Accreditation Council for Graduate Medical Education (ACGME)-accredited Pediatric Surgery training programs in the United States and non-ACGME-accredited programs in Canada. PARTICIPANTS: A total of 1,133 applicants for Pediatric Surgery training. RESULTS: From 2008 to 2012, growth in the annual number of fellowship positions (34-43, 27% increase) exceeded growth in number of applicants (62-69, 11% increase) (p < 0.001). Over the study period, the applicant-to-training ratio peaked at 2.1 to 2.2 in 2017 to 2018 and decreased to 1.4 to 1.6 in 2021 to 2022. The annual match rate for U.S. MD Graduates increased from 60% to 68% (p < 0.05), but decreased from 40% to 22% (p < 0.05) for non-U.S. MD Graduates. In 2022, there was a 3.1-fold difference in match rates between U.S. MD and non-U.S. MD Graduates (68% vs 22%, p < 0.001). The percentage of applicants that matched at their first choice (25%-20%, p < 0.001), second choice (11%-4%, p < 0.001), and third choice (7%-4%, p < 0.001) fellowships decreased over the study period. The percentage of applicants that matched at their fourth choice to least desirable fellowship increased from 23% to 33% (p < 0.001). CONCLUSIONS: The demand for Pediatric Surgery training peaked in 2017 to 2018 and has decreased since. However, the Pediatric Surgery Match remains competitive especially for non-U.S. MD Graduates. More research is needed to understand barriers to matching into Pediatric Surgery for non-U.S. MD Graduates.

The Impact of Post-graduate Year and Program Accreditation Status on In-Training Examination Performance in Orthopaedic Surgery.

Introduction  The progression of medical knowledge competency during surgical residency training is poorly understood. This study measures the acquisition of medical knowledge as orthopedic surgery residents advance during training and the impact of accreditation status on orthopedic in-training examination (OITE) performance. Methods  Orthopedic surgery residents taking the OITE during 2020 and 2021 were included. Residents were grouped into cohorts by post-graduate year (PGY) and Accreditation Council for Graduate Medical Education (ACGME) accreditation status. Comparisons were made with parametric tests. Results  Eight thousand eight hundred and seventy-one ACGME-accredited residents (89%) and 1,057 non-ACGME-accredited residents (11%) were evenly distributed by the PGY level (range, 19-21%). Residents in both ACGME- and non-ACGME-accredited residency programs had a significant increase in OITE performance at each PGY level (P<0.001). At ACGME-accredited programs, OITE performance increased from PGY1 (51%), PGY2 (59%), PGY3 (65%), PGY4 (68%), and PGY5 (70%) (P<0.001). There were progressively smaller percentage increases in OITE performance during accredited residency training (range, 2-8%), but this increase was linear in non-accredited residency training (range, 4%). At each PGY level, residents at accredited programs outperformed their counterparts at non-accredited programs (P<0.001). Conclusion OITE performance increases during residency training. Among ACGME-accredited residents, performance on the OITE progresses rapidly during junior years and plateaus during senior years. Residents in ACGME-accredited residency programs outperform their counterparts in non-accredited residency programs. More research is needed to understand optimal training environments that promote medical knowledge acquisition during orthopedic surgery residency.

A Rare Presentation of Plexiform Schwannoma of the Thumb.

Plexiform schwannomas are rare, benign, neural crest-derived tumors that commonly occur in the hand and upper extremities. They may be sporadic or associated with neurofibromatosis type 2. Although previous literature has described plexiform schwannomas occurring in fingers, nerve and tendon sheaths, and intraosseous lesions, this is the first known case of a plexiform schwannoma of the thumb. This is a case of a growing, painless, subungual mass of the thumb in a 54-year-old patient. After surgical excision and subsequent immunohistochemical examination, the patient was diagnosed with a plexiform schwannoma. This highlights the importance of maintenance a broad differential before surgery and obtaining a proper diagnosis using histopathology.

Intrinsic, widefield optical imaging of hemodynamics in rodent models of Alzheimer's disease and neurological injury.

The complex cerebrovascular network is critical to controlling local cerebral blood flow (CBF) and maintaining brain homeostasis. Alzheimer's disease (AD) and neurological injury can result in impaired CBF regulation, blood-brain barrier breakdown, neurovascular dysregulation, and ultimately impaired brain homeostasis. Measuring cortical hemodynamic changes in rodents can help elucidate the complex physiological dynamics that occur in AD and neurological injury. Widefield optical imaging approaches can measure hemodynamic information, such as CBF and oxygenation. These measurements can be performed over fields of view that range from millimeters to centimeters and probe up to the first few millimeters of rodent brain tissue. We discuss the principles and applications of three widefield optical imaging approaches that can measure cerebral hemodynamics: (1) optical intrinsic signal imaging, (2) laser speckle imaging, and (3) spatial frequency domain imaging. Future work in advancing widefield optical imaging approaches and employing multimodal instrumentation can enrich hemodynamic information content and help elucidate cerebrovascular mechanisms that lead to the development of therapeutic agents for AD and neurological injury.

Acquisition of Medical Knowledge Varies During Allopathic and Osteopathic Orthopedic Surgery Residency Training.

Currently, little is known about the differences in medical knowledge acquisition between osteopathic and allopathic orthopedic surgery residents. The purpose of this study was to determine the relationship between Orthopaedic In-Training Examination (OITE) performance and training pathway in orthopedic surgery. This was a retrospective cohort study of all orthopedic surgery residents taking the OITE during the 2019-2020 academic year. Comparisons in OITE performance were made with parametric tests. A total of 4407 orthopedic surgery residents were in allopathic (86%) and osteopathic (14%) training programs. There was significant improvement in OITE performance between subsequent postgraduate year (PGY) levels among allopathic residents (P<.001). Among osteopathic residents, OITE performance increased between PGY1 and PGY4 (P<.001) but plateaued between PGY4 and PGY5 (P>.05). At the PGY1 level, osteopathic residents had higher OITE performance than allopathic residents (P<.001), but scores were equivalent at the PGY2 to PGY4 levels (P>.05). At the PGY5 level, allopathic residents had higher OITE performance than osteopathic residents (P<.001). Allopathic medical students scored higher on the Step 1 (248±19 vs 242±17, P<.001) and Step 2 (255±16 vs 250±15, P<.001) board examinations. Medical knowledge increases during orthopedic surgery residency. Disparities exist by training pathway, with osteopathic residents outperforming allopathic residents at the PGY1 level but then underperforming at the PGY5 level. Ultimately, this study provides insights into how resident promotion and training pathway impacts the acquisition of medical knowledge during orthopedic surgery residency. [Orthopedics. 2023;46(6):379-383.].

Expanded MutaT7 toolkit efficiently and simultaneously accesses all possible transition mutations in bacteria.

Targeted mutagenesis mediated by nucleotide base deaminase-T7 RNA polymerase fusions has recently emerged as a novel and broadly useful strategy to power genetic diversification in the context of in vivo directed evolution campaigns. Here, we expand the utility of this approach by introducing a highly active adenosine deaminase-T7 RNA polymerase fusion protein (eMutaT7A→G), resulting in higher mutation frequencies to enable more rapid directed evolution. We also assess the benefits and potential downsides of using this more active mutator. We go on to show in Escherichia coli that adenosine deaminase-bearing mutators (MutaT7A→G or eMutaT7A→G) can be employed in tandem with a cytidine deaminase-bearing mutator (MutaT7C→T) to introduce all possible transition mutations simultaneously. We illustrate the efficacy of this in vivo mutagenesis approach by exploring mutational routes to antibacterial drug resistance. This work sets the stage for general application of optimized MutaT7 tools able to induce all types of transition mutations during in vivo directed evolution campaigns across diverse organisms.

Correlation of Scholarly Activity and Departmental Clinical Productivity in a Surgical Subspecialty.

INTRODUCTION: Promotion within academic surgery involves demonstrated excellence in administrative, clinical, and scholarly activities. The present study analyzes the relationship between scholarly and clinical productivity in the field of reconstructive microsurgery. METHODS: This is a retrospective cohort study of microsurgery fellowship directors (MFDs). Data on clinical productivity were obtained from the American Society for Reconstructive Microsurgery and scholarly productivity from Scopus. Outcomes were department annual free flap volume, number of publications, and h-index. Descriptive statistics were calculated, and nonparametric tests were used to compare continuous variables. RESULTS: Thirty-nine MFDs were included in this study. All were plastic surgery residency trained and 38% trained under the independent training pathway. Most underwent formal fellowship training in reconstructive microsurgery (89%). The top three microsurgery fellowships trained 37% of all MFDs. Twenty-five percent of MFDs trained at the institution where they ultimately became program director. Twenty percent of MFDs had an additional degree (4 MS, 2 PhD, and 1 MBA). The median number of annual free flaps performed per institution was 175 (interquartile range [IQR] 122). The median h-index was 17 (IQR 13) resulting from 48 (IQR 99) publications. There was a correlation between department annual free flap volume and h-index (r = 0.333, P = 0.038). CONCLUSIONS: There is a correlation between academic productivity of MFDs and the clinical productivity of their department. This study provides a benchmark for aspiring reconstructive microsurgeons.

Variability in procedure volume of physical medicine and rehabilitation residents graduating from 2014 to 2021.

BACKGROUND: Adequate exposure to commonly performed procedures during physical medicine and rehabilitation (PM&R) residency is an important issue. OBJECTIVE: To assess temporal trends and variabilities in reported procedural volumes, including the number of residents achieving procedure minimum requirements as established by the Accredited Council for Graduate Medical Education (ACGME) PM&R Residency Review Committee. DESIGN: This was a retrospective cohort study of PM&R residents graduating from 2013-2014 to 2020-2021. Descriptive statistics were calculated for tracked procedures and compared over time with analysis of variance (ANOVA) tests. Variability was calculated as the procedure volume difference between the 90th and 10th percentile groups. SETTING: ACGME-accredited PM&R residency training programs. PARTICIPANTS: A total of 3231 PM&R residents graduating from 2014 to 2021. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Reported procedure volume and number of residents achieving minimum requirements. RESULTS: Total procedure volume increased over the study period (436 ± 225 to 523 ± 238, p = .013). The percentage of all procedures that were performed versus observed was stable over the study period (81%-77%, p = .234). Variability in total reported procedure volume remained stable over the study period. The percentage of PM&R residents not achieving minimum requirements ranged from 2% for peripheral joint injections to 22% for ultrasound in the contemporary training period. CONCLUSIONS: The volume of reported procedures has increased along with the number of PM&R residency programs and residents. Variabilities in total reported procedure volume were stable over time, but PM&R residents struggle to obtain minimum requirements for ultrasound procedures.

Impact of Orthopaedic Surgeons on National Institutes of Health Funding for Hip and Knee Arthroplasty Research.

BACKGROUND: The National Institutes of Health (NIH) remains one of the predominant sources of biomedical research funding in the United States, yet its impact on total hip and knee arthroplasty research is poorly understood. This study defines the portfolio of NIH funding for total joint arthroplasty (TJA) and the impact of orthopaedic surgeons on this portfolio. METHODS: The Research Portfolio Online Reporting Tools Expenditures and Results (RePORTER) database was queried for NIH grants that had been awarded for total hip and knee arthroplasty and total NIH funding from 2010 to 2020. Compound annual growth rates (CAGRs) were calculated. Funding totals were compared with those from 20 other clinical areas. The principal investigators (PIs) and grants were characterized, and comparisons were made with use of the Student t test. RESULTS: A total of 489 grants were awarded, totaling $181 million (CAGR of 10.3%). This was >3 times the growth rate for the total NIH budget (CAGR of 2.9%), which increased from $31.2 to $41.7 billion over the 11-year period. When compared with 20 other clinical areas, TJA received the least amount of NIH funding over that period. Alzheimer disease received the most funding ($12.1 billion, CAGR of 19.5%), and cerebral palsy received the penultimate amount of funding ($284 million, CAGR of 6.3%). The R01 grant mechanism was the predominant source (63.1%), and the Mayo Clinic (Rochester, Minnesota) received the most funding (9.7%). Departments of orthopaedic surgery were awarded the most funding (23.5%), yet only 20 orthopaedic surgeons were identified as PIs (16.0%). There were no significant differences in NIH funding totals by PI demographic and academic characteristics (p > 0.05), yet orthopaedic surgeons had among the highest Hirsch indices (h-indices) (p < 0.001). Funding supported clinical (63.5%), translational (19.3%), basic science (7.1%), and other types (10.1%) of research. The top areas with funding were postoperative complications (44.4%), postoperative pain management (17.6%), rehabilitation (15.1%), and implant design (12.4%). CONCLUSIONS: There is a paucity of orthopaedic surgeon representation among NIH grants awarded for TJA. Opportunities may exist for orthopaedic surgeons to collaborate in identified areas of clinical interest. Additional research is needed to understand the obstacles to obtaining NIH grant funding for orthopaedic surgeon PIs. CLINICAL RELEVANCE: Increasing the levels of funding from the NIH is a strategic priority for departments of orthopaedic surgery. Understanding levels of funding for clinical areas in total joint arthroplasty is critical to foster research and discovery support from the NIH.

Prostate-Specific Antigen Doubling Time Kinetics following Radical Prostatectomy to Guide Need for Treatment Intervention: Validation of Low-Risk Recurrences.

Biochemical recurrence (BCR) following radical prostatectomy (RP) has a limited ability to predict prostate cancer (PC) progression, leading to overtreatment, decreased quality of life, and additional expenses. Previously, we established that one-third of men with BCR in our group experienced low-risk recurrences that were safely observed without treatment. Our retrospective cohort analysis of 407 BCR patients post RP validates the use of PSA doubling time (DT) kinetics to direct active observation (AO) versus treatment following RP. The primary outcome was no need for treatment according to the predictive value of models of ROC analysis. The secondary outcome was PC-specific mortality (PCSM) according to Kaplan−Meier analysis. A total of 1864 men underwent RP (June 2002−September 2019); 407 experienced BCR (PSA > 0.2 ng/dL, ×2), with a median follow-up of 7.6 years. In adjusted regression analysis, initial PSADT > 12 months and increasing DT were significant predictors for AO (p < 0.001). This model (initial PSADT and DT change) was an excellent predictor of AO in ROC analysis (AUC = 0.83). No patients with initial PSADT > 12 months and increasing DT experienced PCSM. In conclusion, the combination of PSADT > 12 months and increasing DT was an excellent predictor of AO. This is the first demonstration that one-third of BCRs are at low risk of PCSM and can be managed without treatment via DT kinetics.

Charting Outcomes in the Hand Surgery Fellowship Match.

PURPOSE: The hand surgery fellowship match attracts applicants from general, plastic, and orthopedic surgery residency training. The purpose of this study was to understand recent trends in applications and match rates in the hand surgery fellowship match. METHODS: The National Resident Matching Program provided program and applicant data from the hand surgery fellowship match (2012-2020). The primary outcomes of interest were match rates and number of unfilled fellowship positions by specialty. Trends over time and comparisons of the percentage of unfilled spots by specialty were observed. RESULTS: The total number of applicants decreased from 199 to 188 (5.5% decrease), while the number of available positions increased from 150 to 177 (18.0% increase) during the study period. The increase in available positions was driven primarily by orthopedic fellowships, which increased from 124 to 149 (20.2% increase). The percentage of applicants that did not match to a hand surgery fellowship decreased from 24.6% in 2012 to 5.9% in 2020. United States graduates had higher match rates than non-United States graduates during each year, but this disparity narrowed over time. Most applicants matched at one of their top 3 choices (first choice, 33.3%; second choice, 12.9%; third choice, 7.9%). Applicants matching at their first choice increased from 28.1% in 2012 to 39.4% in 2020. Plastic surgery hand surgery fellowships had a higher rate of unmatched positions relative to orthopedic surgery fellowships (6.1% vs 2.2%). CONCLUSIONS: Match rates in the hand surgery fellowship match have increased because of an overall increase in training positions and decrease in applicants. More research is needed to understand disparities in match rates by specialty. CLINICAL RELEVANCE: The diverse training experiences of hand surgeons historically have been viewed as a strength for the specialty. Understanding recent trends in the hand surgery fellowship match by specialty can help future applicants and faculty anticipate likely match outcomes.

Surgical Benchmarks for ACGME-accredited Adult Reconstructive Orthopaedic Fellowship Training.

INTRODUCTION: Higher case volumes correlate with improved outcomes in total joint arthroplasty surgery. The purpose of this study was to understand the effect of adult reconstruction fellowship training on reported case volume in a contemporary cohort of orthopaedic surgeons. METHODS: The Accreditation Council for Graduate Medical Education provided case logs for orthopaedic surgery residents and adult reconstructive orthopaedic fellows from 2017 to 2018 to 2020 to 2021. Reported case volumes for total joint arthroplasty surgeries were compared using Student t tests. RESULTS: One hundred eighty-three adult reconstructive orthopaedic fellows and 3,000 orthopaedic surgery residents were included. Residents reported more total hip arthroplasty cases (98.9 ± 30 to 106.1 ± 33, 7.3% increase, P < 0.05) and total knee arthroplasty cases (126.0 ± 41 to 136.5 ± 44, 8.3% increase, P < 0.05) over the study period. On average, fellows reported 439.6 total cases: primary total knee arthroplasty, 164.9 cases (37.5%); primary total hip arthroplasty, 146.8 cases (33.4%); revision total knee arthroplasty, 35.2 cases (8.0%); revision total hip arthroplasty, 33.0 cases (7.5%); unicompartmental knee arthroplasty, 4.4 cases (1.0%); and other, 55.0 cases (12.5%). Overall, adult reconstructive orthopaedic fellowship reported between 1.7- and 2.0-fold more joint arthroplasty cases during 1 year of fellowship training than 5 years of residency ( P < 0.001). DISCUSSION: Adult reconstructive orthopaedic fellowship training provides notable exposure to additional cases after residency training. The results from this study may inform prospective applicants on the effect of fellowship training in total joint arthroplasty and help establish benchmarks in case volume for independent practice.

Cortical Anoxic Spreading Depolarization During Cardiac Arrest is Associated with Remote Effects on Peripheral Blood Pressure and Postresuscitation Neurological Outcome.

BACKGROUND: Spreading depolarizations (SDs) are self-propagating waves of neuronal and glial depolarizations often seen in neurological conditions in both humans and animal models. Because SD is thought to worsen neurological injury, the role of SD in a variety of cerebral insults has garnered significant investigation. Anoxic SD is a type of SD that occurs because of anoxia or asphyxia. Although asphyxia leading to a severe drop in blood pressure may affect cerebral hemodynamics and is widely known to cause anoxic SD, the effect of anoxic SD on peripheral blood pressure in the extremities has not been investigated. This relationship is especially important to understand for conditions such as circulatory shock and cardiac arrest that directly affect both peripheral and cerebral perfusion in addition to producing anoxic SD in the brain. METHODS: In this study, we used a rat model of asphyxial cardiac arrest to investigate the role of anoxic SD on cerebral hemodynamics and metabolism, peripheral blood pressure, and the relationship between these variables in 8- to 12-week-old male rats. We incorporated a multimodal monitoring platform measuring cortical direct current simultaneously with optical imaging. RESULTS: We found that during anoxic SD, there is decoupling of peripheral blood pressure from cerebral blood flow and metabolism. We also observed that anoxic SD may modify cerebrovascular resistance. Furthermore, shorter time difference between anoxic SDs measured at different locations in the same rat was associated with better neurological outcome on the basis of the recovery of electrocorticography activity (bursting) immediately post resuscitation and the neurological deficit scale score 24 h post resuscitation. CONCLUSIONS: To our knowledge, this is the first study to quantify the relationship between peripheral blood pressure, cerebral hemodynamics and metabolism, and neurological outcome in anoxic SD. These results indicate that the characteristics of SD may not be limited to cerebral hemodynamics and metabolism but rather may also encompass changes in peripheral blood flow, possibly through a brain-heart connection, providing new insights into the role of anoxic SD in global ischemia and recovery.

Quantifying the confounding effect of pigmentation on measured skin tissue optical properties: a comparison of colorimetry with spatial frequency domain imaging.

SIGNIFICANCE: Spatial frequency domain imaging (SFDI) is a wide-field diffuse optical imaging technique for separately quantifying tissue reduced scattering (µs ' ) and absorption (µa) coefficients at multiple wavelengths, providing wide potential utility for clinical applications such as burn wound characterization and cancer detection. However, measured µs ' and µa can be confounded by absorption from melanin in patients with highly pigmented skin. This issue arises because epidermal melanin is highly absorbing for visible wavelengths and standard homogeneous light-tissue interaction models do not properly account for this complexity. Tristimulus colorimetry (which quantifies pigmentation using the L * "lightness" parameter) can provide a point of comparison between µa, µs ' , and skin pigmentation. AIM: We systematically compare SFDI and colorimetry parameters to quantify confounding effects of pigmentation on measured skin µs ' and µa. We assess the correlation between SFDI and colorimetry parameters as a function of wavelength. APPROACH: µs ' and µa from the palm and ventral forearm were measured for 15 healthy subjects with a wide range of skin pigmentation levels (Fitzpatrick types I to VI) using a Reflect RS® (Modulim, Inc., Irvine, California) SFDI instrument (eight wavelengths, 471 to 851 nm). L * was measured using a Chroma Meter CR-400 (Konica Minolta Sensing, Inc., Tokyo). Linear correlation coefficients were calculated between L * and µs ' and between L * and µa at all wavelengths. RESULTS: For the ventral forearm, strong linear correlations between measured L * and µs ' values were observed at shorter wavelengths (R > 0.92 at ≤659 nm), where absorption from melanin confounded the measured µs ' . These correlations were weaker for the palm (R < 0.59 at ≤659 nm), which has less melanin than the forearm. Similar relationships were observed between L * and µa. CONCLUSIONS: We quantified the effects of epidermal melanin on skin µs ' and µa measured with SFDI. This information may help characterize and correct pigmentation-related inaccuracies in SFDI skin measurements.

Analysis of Strengths in Exposure to Cases During Plastic and Orthopaedic Hand Surgery Fellowships.

INTRODUCTION: Prospective residents interested in hand surgery must decide to apply for hand surgery fellowships sponsored by different specialties. This study compares case volumes reported during plastic surgery and orthopaedic hand surgery fellowships. METHODS: The American Council for Graduate Medical Education case logs of accredited hand surgery fellowships were analyzed for hand surgery cases (2012 to 2013 to 2020 to 2021). The reported case volume was compared by specialty. Temporal trends were described, intrapathway variabilities calculated, and interpathway differences calculated with Student t -tests. RESULTS: Two hundred plastic surgery (13%) and 1,323 orthopaedic (87%) hand surgery fellows were included. The number of orthopaedic hand surgery fellowships increased from 58 in 2012 to 2013 to 70 in 2020 to 2021 (21% increase), whereas the number of plastic surgery fellowships was stable at 16. Orthopaedic hand surgery fellows reported more hand surgery cases (764 ± 22 versus 628 ± 226), arthroscopy cases (53 ± 54 versus 23 ± 38), and miscellaneous hand surgery cases (42 ± 23 versus 31 ± 18) than plastic surgery hand fellows. Plastic surgery hand fellows reported more cases in wound closure with graft, wound reconstruction with flap, nerve injury, and vascular repair. Overall, orthopaedic surgery offered more experience in 15 case categories (58%), while plastic surgery offered more experience in five case categories (19%). Six case categories (23%) had no difference between specialties. DISCUSSION: Although orthopaedic hand surgery fellowship affords more cases overall, plastic surgery hand fellowships have unique strengths in wound reconstruction with grafts and flaps, nerve injury, and vascular repair. Ultimately, results from this study create a benchmark to improve future training opportunities for hand surgery fellows and orthopaedic surgery residents.

The Orthopaedic Match: Defining the Academic Profile of Successful Candidates.

BACKGROUND: Research productivity forms a vital part of the resident selection process and can markedly affect the chance of a successful match. Current reports regarding the publication record among prospective orthopaedic surgery residents are likely inaccurate. Potential applicants have a poor understanding of the strength of their research credentials in comparison to other candidates. METHODS: We identified matched applicants from the 2013 to 2017 orthopaedic surgery residency application cycles. We performed a bibliometric analysis of these residents using Scopus, PubMed, and Google Scholar to identify published articles and calculate the h-index of each applicant at the time of application. Details were collected on medical school, advanced degrees, publication type, first authorship, and article relatedness to orthopaedic surgery. RESULTS: We included 3,199 matched orthopaedic surgery applicants. At the time of application, the median h-index was 0, the median number of publications was 1, and 40% of successful candidates did not hold any publications. The h-index (R 0.08, P < 0.0001) and median number of publications of matched orthopaedic surgery residency candidates significantly increased (R 0.09, P < 0.0001) across application cycles. Furthermore, the proportion of matched applicants without publications at the time of application significantly decreased (R -0.90, P = 0.0350). Conversely, the percentage of articles first-authored by applicants decreased (R -0.96, P = 0.0093), but article relatedness to orthopaedic surgery remained constant (R 0.82, P = 0.0905). Strikingly, notable changes were observed in the type of articles published by successful applicants: the proportion of preclinical studies decreased (R -0.07, P = 0.0041), whereas clinical research articles increased (R 0.07, P = 0.0024). CONCLUSION: The publication count held by successful orthopaedic surgery applicants is substantially lower than the nationally reported average. Matched orthopaedic surgery candidates demonstrate increasingly impressive research achievements each application cycle. However, increased academic productivity comes at the cost of reduced project responsibility and a shift toward faster-to-publish articles.

High-speed quantitative optical imaging of absolute metabolism in the rat cortex.

Significance: Quantitative measures of blood flow and metabolism are essential for improved assessment of brain health and response to ischemic injury. Aim: We demonstrate a multimodal technique for measuring the cerebral metabolic rate of oxygen ( CMRO 2 ) in the rodent brain on an absolute scale ( µ M O 2 / min ). Approach: We use laser speckle imaging at 809 nm and spatial frequency domain imaging at 655, 730, and 850 nm to obtain spatiotemporal maps of cerebral blood flow, tissue absorption ( µ a ), and tissue scattering ( µ s ' ). Knowledge of these three values enables calculation of a characteristic blood flow speed, which in turn is input to a mathematical model with a "zero-flow" boundary condition to calculate absolute CMRO 2 . We apply this method to a rat model of cardiac arrest (CA) and cardiopulmonary resuscitation. With this model, the zero-flow condition occurs during entry into CA. Results: The CMRO 2 values calculated with our method are in good agreement with those measured with magnetic resonance and positron emission tomography by other groups. Conclusions: Our technique provides a quantitative metric of absolute cerebral metabolism that can potentially be used for comparison between animals and longitudinal monitoring of a single animal over multiple days. Though this report focuses on metabolism in a model of ischemia and reperfusion, this technique can potentially be applied to far broader types of acute brain injury and whole-body pathological occurrences.

Characterizing reduced scattering coefficient of normal human skin across different anatomic locations and Fitzpatrick skin types using spatial frequency domain imaging.

SIGNIFICANCE: Spatial frequency domain imaging (SFDI), a noncontact wide-field imaging technique using patterned illumination with multiple wavelengths, has been used to quantitatively measure structural and functional parameters of in vivo tissue. Using SFDI in a porcine model, we previously found that scattering changes in skin could potentially be used to noninvasively assess burn severity and monitor wound healing. Translating these findings to human subjects necessitates a better understanding of the variation in "baseline" human skin scattering properties across skin types and anatomical locations. AIM: Using SFDI, we aim to characterize the variation in the reduced scattering coefficient (µs') for skin across a range of pigmentation and anatomic sites (including common burn locations) for normal human subjects. These measurements are expected to characterize baseline human skin properties to inform our use of SFDI for clinical burn severity and wound healing assessments. APPROACH: SFDI was used to measure µs' in the visible- and near-infrared regime (471 to 851 nm) in 15 subjects at 10 anatomical locations. Subjects varied in age, gender, and Fitzpatrick skin type. RESULTS: For all anatomical locations, the coefficient of variation in measured µs' decreased with increasing wavelength. High intersubject variation in µs' at visible wavelengths coincided with large values of the melanin extinction coefficient at those wavelengths. At 851 nm, where intersubject variation in µs' was smallest for all anatomical locations and absorption from melanin is minimal, significant intrasubject differences in µs' were observed at the different anatomical locations. CONCLUSIONS: Our study is the first report of wide-field mapping of human skin scattering properties across multiple skin types and anatomical locations using SFDI. Measured µs' values varied notably between skin types at wavelengths where absorption from melanin was prominent. Additionally, µs' varied considerably across different anatomical locations at 851 nm, where the confounding effects from melanin absorption are minimized.

Discovery of a readily heterologously expressed Rubisco from the deep sea with potential for CO2 capture.

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key CO2-fixing enzyme in photosynthesis, is notorious for its low carboxylation. We report a highly active and assembly-competent Form II Rubisco from the endosymbiont of a deep-sea tubeworm Riftia pachyptila (RPE Rubisco), which shows a 50.5% higher carboxylation efficiency than that of a high functioning Rubisco from Synechococcus sp. PCC7002 (7002 Rubisco). It is a simpler hexamer with three pairs of large subunit homodimers around a central threefold symmetry axis. Compared with 7002 Rubisco, it showed a 3.6-fold higher carbon capture efficiency in vivo using a designed CO2 capture model. The simple structure, high carboxylation efficiency, easy heterologous soluble expression/assembly make RPE Rubisco a ready-to-deploy enzyme for CO2 capture that does not require complex co-expression of chaperones. The chemosynthetic CO2 fixation machinery of chemolithoautotrophs, CO2-fixing endosymbionts, may be more efficient than previously realized with great potential for next-generation microbial CO2 sequestration platforms.