Author Correction: Variable water input controls evolution of the Lesser Antilles volcanic arc.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Variable water input controls evolution of the Lesser Antilles volcanic arc.

Oceanic lithosphere carries volatiles, notably water, into the mantle through subduction at convergent plate boundaries. This subducted water exercises control on the production of magma, earthquakes, formation of continental crust and mineral resources. Identifying different potential fluid sources (sediments, crust and mantle lithosphere) and tracing fluids from their release to the surface has proved challenging1. Atlantic subduction zones are a valuable endmember when studying this deep water cycle because hydration in Atlantic lithosphere, produced by slow spreading, is expected to be highly non-uniform2. Here, as part of a multi-disciplinary project in the Lesser Antilles volcanic arc3, we studied boron trace element and isotopic fingerprints of melt inclusions. These reveal that serpentine-that is, hydrated mantle rather than crust or sediments-is a dominant supplier of subducted water to the central arc. This serpentine is most likely to reside in a set of major fracture zones subducted beneath the central arc over approximately the past ten million years. The current dehydration of these fracture zones coincides with the current locations of the highest rates of earthquakes and prominent low shear velocities, whereas the preceding history of dehydration is consistent with the locations of higher volcanic productivity and thicker arc crust. These combined geochemical and geophysical data indicate that the structure and hydration of the subducted plate are directly connected to the evolution of the arc and its associated seismic and volcanic hazards.

BREAST-Q REACT: Qualitative Assessment of the Design, Functionality, and Clinical Utility of a New Score Interpretation Tool.

BACKGROUND: The BREAST-Q real-time engagement and communication tool (REACT) was developed to aid with BREAST-Q score interpretation and guide patient-centered care. OBJECTIVE: The purpose of this qualitative study was to examine the perspectives of patients and providers on the design, functionality, and clinical utility of REACT and refine the REACT based on their recommendations. METHODS: We conducted three patient focus groups with women who were at least 6 postoperative months from their postmastectomy breast reconstruction, and two provider focus groups with plastic surgeons, breast surgeons, and advanced practice providers. Focus groups were audio-taped, transcribed verbatim, and analyzed thematically. RESULTS: A total of 18 breast reconstruction patients and 14 providers participated in the focus groups. Themes identified by thematic analysis were organized into two categories: (1) design and functionality, and (2) clinical utility. On the design and functionality of REACT, four major themes were identified: visual appeal and usefulness; contextualizing results; ability to normalize patients' experiences, noting participants' concerns; and suggested modifications. On the clinical utility of REACT, three major themes were identified: potential to empower patients to communicate with their providers; increase patient and provider motivation to engage with the BREAST-Q; and effective integration into clinical workflow. CONCLUSION: Patients and providers in this qualitative study indicated that with some modifications, REACT has a great potential to elevate the clinical utility of the BREAST-Q by enhancing patient-provider communication that can lead to patient-centered, clinically relevant action recommendations based on longitudinal BREAST-Q scores.

Reducing Disparities: Regional Anesthesia Blocks for Mastectomy with Reconstruction Within Standardized Regional Anesthesia Pathways.

BACKGROUND: Recent data suggest disparities in receipt of regional anesthesia prior to breast reconstruction. We aimed to understand factors associated with block receipt for mastectomy with immediate tissue expander (TE) reconstruction in a high-volume ambulatory surgery practice with standardized regional anesthesia pathways. PATIENTS AND METHODS: Patients who underwent mastectomy with immediate TE reconstruction from 2017 to 2022 were included. All patients were considered eligible for and were offered preoperative nerve blocks as part of routine anesthesia care. Interpreters were used for non-English speaking patients. Patients who declined a block were compared with those who opted for the procedure. RESULTS: Of 4213 patients who underwent mastectomy with immediate TE reconstruction, 91% accepted and 9% declined a nerve block. On univariate analyses, patients with the lowest rate of block refusal were white, non-Hispanic, English speakers, patients with commercial insurance, and patients undergoing bilateral reconstruction. The rate of block refusal went down from 12 in 2017 to 6% in 2022. Multivariable logistic regression demonstrated that older age (p = 0.011), Hispanic ethnicity (versus non-Hispanic; p = 0.049), Medicaid status (versus commercial insurance; p < 0.001), unilateral surgery (versus bilateral; p = 0.045), and reconstruction in earlier study years (versus 2022; 2017, p < 0.001; 2018, p < 0.001; 2019, p = 0.001; 2020, p = 0.006) were associated with block refusal. CONCLUSIONS: An established preoperative regional anesthesia program with blocks offered to all patients undergoing mastectomy with TE reconstruction can result in decreased racial disparities. However, continued differences in age, ethnicity, and insurance status justify future efforts to enhance preoperative educational efforts that address patient hesitancies in these subpopulations.

Early Complications in Prepectoral Tissue Expander-Based Breast Reconstruction.

BACKGROUND: Prepectoral implant placement for postmastectomy breast reconstruction has increased in recent years. Benefits of prepectoral reconstruction may include lack of animation deformities and reduced postoperative pain, but its complication profile is currently unclear. This study aimed to examine the complication profile of prepectoral tissue expanders (TEs) to determine factors associated with TE loss. METHODS: A retrospective review was performed to identify all patients who underwent immediate prepectoral TE reconstruction from January 2018 to June 2021. The decision to use the prepectoral technique was based on mastectomy skin quality and patient comorbidities. Patient demographics, comorbidities, and operative details were evaluated. Outcomes of interest included TE loss, seroma, hematoma, infection/cellulitis, mastectomy skin flap necrosis requiring revision, and TE exposure. Logistic regression analysis was performed to identify factors associated with TE loss. RESULTS: The study identified 1225 TEs. The most frequent complications were seroma (8.7%, n = 106), infection/cellulitis (8.2%, n = 101), and TE loss (4.2%, n = 51). Factors associated with TE loss in the univariate analysis included ethnicity, history of smoking, body mass index, mastectomy weight, and neoadjuvant chemotherapy. In the multivariate regression analysis, only mastectomy weight had a positive association with TE loss (odds ratio, 1.001; p = 0.016). CONCLUSION: Prepectoral two-stage breast reconstruction can be performed safely with an acceptable early complication profile. The study data suggest that increasing mastectomy weight is the most significant factor associated with TE loss. Further research examining the quality of the soft tissue envelope and assessing patient-reported outcomes would prove beneficial.

Analyzing mastectomy and reconstruction weight in immediate autologous breast reconstruction: A preliminary study.

BACKGROUND: This study aims to explore the ideal breast size by assessing the relationship between mastectomy to free flap weight ratio and complications as well as patient-reported outcomes in autologous breast reconstruction (ABR). METHOD: A retrospective review of patients undergoing bilateral immediate ABR with mastectomy and flap weights available was completed. Patients were divided into three groups based on the ratio of mastectomy to flap weights. The patients were grouped as "maintained" if the flap weight was within 10% of the mastectomy weight. Patients with a weight difference greater than 10% were used to declare "downsized" or "upsized." Outcomes included complications and four domains of the BREAST-Q at 1-year postoperatively. RESULTS: Three hundred and fifty-nine patients were included in the analysis, of which 112 were downsized, 91 maintained, and 156 upsized, respectively. Presence of complications did not significantly differ among the groups. At 1-year postoperatively, Sexual Well-being significantly differed (p = 0.033). Between preoperative and 1 year, patients who upsized experienced an improvement in Satisfaction with Breasts by 16 points (p < 0.001), while patients who downsized experienced a decline in Physical Well-being of the Chest by 7 points (p = 0.016). Multivariable linear regression model showed that Sexual Well-being was 13 points lower in the downsized cohort than in the maintained cohort (ß = -13, 95% confidence interval: -21 to -5.4; p = 0.001). CONCLUSION: Although complication rates do not significantly differ between the three cohorts, patients who downsize may have lower Sexual Well-being postoperatively. Surgeons should consider our preliminary findings to counsel patients preoperatively about the predicted breast size and the impact of downsizing on sexual health.

Clinical, functional, and patient-reported outcomes of radial forearm versus anterolateral thigh free tissue transfer for reconstruction of glossectomy defects.

BACKGROUND: There is a lack of literature of health-related quality of life endpoints for radial forearm (RF) versus anterolateral thigh (ALT) free flap reconstruction for glossectomy defects. Our goal was to perform a comprehensive evaluation of clinical, functional, and quality of life outcomes after glossectomy reconstruction using a RF or ALT flap. METHODS: A retrospective review was performed on patients who underwent glossectomy and immediate reconstruction with RF or ALT flaps between 2016 and 2021. Outcomes of interest included readmission and reoperation rates, functional assessments, tracheostomy and gastrostomy tube status, and FACE-Q Head and Neck Cancer scores. RESULTS: Seventy-eight patients consisting of 54 RF and 24 ALT free flaps were included. ALT patients had a larger median flap size (72 vs. 48 cm2 , p = 0.021) and underwent mandibulotomy (50% vs. 7.4%, p < 0.0001) and base of tongue resection (58.3% vs. 24.1%, p = 0.005) at higher rates. No significant differences were found with respect to other outcomes. CONCLUSION: The RF and ALT flaps are suitable for glossectomy reconstruction, with minimal differences seen in postoperative outcomes. Our study suggests that ALT can be used in patients with base of tongue and larger defect sizes, while providing similar functional and clinical outcomes to RF reconstruction.

A preliminary analysis of patient reported outcomes following posterolateral mandible reconstruction: The role of flap type.

BACKGROUND: The choice of tissue type for free flap reconstruction of posterolateral mandible resections is dependent on patient and defect characteristics. We compared clinical and patient-reported outcomes following reconstruction of these defects with a soft tissue or bony free flap. METHODS: A retrospective review was performed on patients who underwent posterolateral segmental mandibulectomy with immediate free flap reconstruction at MSKCC from 2006 to 2021. Outcomes of interest were patient-reported outcome measures (PROMs) assessed by FACE-Q surveys and complications at the flap recipient site. RESULTS: Ninety patients received a bony flap and 24 patients received a soft tissue flap. Patients reconstructed with soft tissue flaps had greater rates of composite soft tissue defects (p < 0.0001), condyle resection (p = 0.001), and peripheral vascular disease (p = 0.035). Complication rates were similar between the cohorts (p > 0.05). Bony flaps scored higher on multiple FACE-Q scales: Facial Appearance (p = 0.023) Eating/Drinking (p = 0.029), Smiling (p = 0.012), Speaking (p < 0.001), Swallowing (p = 0.012), Smiling Distress (p = 0.037), and Speaking Distress (p = 0.001). CONCLUSION: Reconstruction of posterolateral mandibular defects has a similar complication profile when utilizing a bony or soft tissue free flap. Bony flaps may perform better with respect to PROMs. Reconstructive surgeons should consider using bony flap reconstruction to achieve higher patient satisfaction and quality of life.

Safety and Effectiveness of Antidysrhythmic Drugs for Pharmacologic Cardioversion of Recent-Onset Atrial Fibrillation: a Systematic Review and Bayesian Network Meta-analysis.

PURPOSE: The available evidence to determine which antidysrhythmic drug is superior for pharmacologic cardioversion of recent-onset (onset within 48 h) atrial fibrillation (AF) is uncertain. We aimed to identify the safest and most effective agent for pharmacologic cardioversion of recent-onset AF in the emergency department. METHODS: We searched MEDLINE, Embase, and Web of Science from inception to February 21, 2023 (PROSPERO: CRD42018083781). Eligible studies were randomized controlled trials that enrolled adult participants with AF ≤ 48 h, compared a guideline-recommended antidysrhythmic drug with another antidysrhythmic drug or a different formulation of the same drug or placebo and reported specific adverse events. The primary outcome was immediate, serious adverse event - cardiac arrest, sustained ventricular tachydysrhythmia, atrial flutter 1:1 atrioventricular conduction, hypotension, and bradycardia. Additional analyses included the outcomes of conversion to sinus rhythm within 4 h and 24 h. We extracted data according to PRISMA-NMA and appraised trials using Cochrane RoB 2. We performed Bayesian network meta-analysis (NMA) using a Markov Chain Monte Carlo method with random-effect model and vague prior distribution to calculate odds ratios with 95% credible intervals. We assessed confidence using CINeMA. We used surface under the cumulative ranking curve (SUCRA) to rank agent(s). RESULTS: The systematic review initially identified 5545 studies. Twenty-five studies met eligibility criteria, and 22 studies (n = 3082) provided data for NMA, which demonstrated that vernakalant (SUCRA = 70.9%) is most likely to be safest. Additional effectiveness NMA demonstrated that flecainide (SUCRA = 89.0%) is most likely to be superior for conversion within 4 h (27 studies; n = 2681), and ranolazine-amiodarone IV (SUCRA 93.7%) is most likely to be superior for conversion within 24 h (24 studies; n = 3213). Confidence in the NMA estimates is variable and limited mostly by within-study bias and imprecision. CONCLUSIONS: Among guideline-recommended antidysrhythmic drugs, the combination of digoxin IV and amiodarone IV is definitely among the least safe for cardioversion of recent onset AF; flecainide, vernakalant, ibutilide, propafenone, and amiodarone IV are definitely among the most effective for cardioversion within 4 h; flecainide is definitely among the most effective for cardioversion within 24 h. Further, randomized controlled trials with predetermined and strictly defined, hemodynamic adverse event outcomes are recommended.

Artificial Intelligence to Determine Fetal Sex.

OBJECTIVE: This proof-of-concept study assessed how confidently an artificial intelligence (AI) model can determine the sex of a fetus from an ultrasound image. STUDY DESIGN: Analysis was performed using 19,212 ultrasound image slices from a high-volume fetal sex determination practice. This dataset was split into a training set (11,769) and test set (7,443). A computer vision model was trained using a transfer learning approach with EfficientNetB4 architecture as base. The performance of the computer vision model was evaluated on the hold out test set. Accuracy, Cohen's Kappa and Multiclass Receiver Operating Characteristic area under the curve (AUC) were used to evaluate the performance of the model. RESULTS: The AI model achieved an Accuracy of 88.27% on the holdout test set and a Cohen's Kappa score 0.843. The ROC AUC score for Male was calculated to be 0.896, for Female a score of 0.897, for Unable to Assess a score of 0.916, and for Text Added a score of 0.981 was achieved. CONCLUSION: This novel AI model proved to have a high rate of fetal sex capture that could be of significant use in areas where ultrasound expertise is not readily available. KEY POINTS: · This is the first proof-of-concept AI model to determine fetal sex.. · This study adds to the growing research in ultrasound AI.. · Our findings demonstrate AI integration into obstetric care..

Surgical Delay of Thoracodorsal Artery Perforator Flaps for Total Autologous Breast Reconstruction.

BACKGROUND: When abdomen-based free flap reconstruction is contraindicated, the muscle-sparing thoracodorsal artery perforator (TDAP) flap may be considered for total autologous breast reconstruction. The TDAP flap is often limited by volume and is prone to distal flap necrosis. We aim to demonstrate our experience combining the delay phenomenon with TDAP flaps for total autologous breast reconstruction. METHODS: Patients presenting for autologous breast reconstruction between April 2021 and August 2023 were recruited for surgically delayed TDAP flap reconstruction when abdominally based free flap reconstruction was contraindicated because of previous abdominal surgery or poor perforator anatomy. We dissected the TDAP flap except for a distal skin bridge and then reconstructed the breast 1 to 7 days later. Data included flap dimensions (in centimeters × centimeters), delay time (in days), predelay and postdelay perforator caliber (in millimeters) and flow (in centimeters per second), operative time (in minutes), hospital length of stay (in days), complications/revisions, and follow-up time (in days). RESULTS: Fourteen patients and 16 flaps were included in this study. Mean age and body mass index of patients were 55.9 ± 9.6 years and 30.1 ± 4.3 kg/m2, respectively. Average flap skin island length and width were 32.1 ± 3.3 cm (n = 8 flaps) and 8.8 ± 0.7 cm (n = 5 flaps), respectively. Beveled flap width reached 16.0 ± 2.2 cm (n = 3 flaps). Average time between surgical delay and reconstruction was 2.9 days, ranging from 1 to 7 days (n = 18 flaps). Mean predelay and postdelay TDAP vessel caliber and flow measured by Doppler ultrasound increased from 1.4 ± 0.3 to 1.8 ± 0.3 mm (P = 0.03) and 13.3 ± 5.2 to 43.4 ± 18.8 cm/s (P = 0.03), respectively (n = 4 flaps). Complications included 1 donor site seroma and 1 mastectomy skin flap necrosis. Follow-up ranged from 4 to 476 days (n = 17 operations). CONCLUSIONS: We demonstrate surgically delayed TDAP flaps as a viable option for total autologous breast reconstruction. Our series of flaps demonstrated increased perforator caliber and flow and enlarged volume capabilities and had no incidences of flap necrosis.

Increased Time Interval of Postoperative Flap Monitoring After Autologous Breast Reconstruction.

BACKGROUND: Hourly flap checks are the most common means of flap monitoring during the first 24 hours following autologous breast reconstruction (ABR). This practice often requires intensive care unit (ICU) admission, which is a key driver of health care costs and decreased patient satisfaction. This study addresses these issues by demonstrating decreased cost and length of admission associated with a 4-hour interval between flap checks during the first 24 hours following ABR. METHODS: This is a retrospective review of ABR surgeries performed by multiple surgeons from 2017 to 2020. Two cohorts were identified, one that underwent flap checks every hour in the ICU (Q1 cohort) and the other that underwent flap checks every 4 hours on the hospital floor (Q4 cohort). Our primary outcome measures were length of stay (LOS), flap takebacks, flap loss, and encounter cost. RESULTS: Rates of flap takeback and loss did not differ between cohorts (P = 0.18, P = 0.21). The Q4 cohort's average LOS was shorter than the Q1 cohort (P = 0.002). The Q4 cohort's average cost was also $25,554.80 less than the Q1 cohort (P < 0.001). This association persisted after controlling for LOS, operating room takeback, timing and laterality of reconstruction, and flap configuration (hazard ratio = 0.65, P = 0.0007). CONCLUSION: This study demonstrates the benefits of lengthened flap check intervals during the first 24 hours following ABR. These intervals decrease the cost of ABR while also maintaining safety, making ABR a more accessible option for breast reconstruction patients.

Incidental Renal Cysts Found by Point-of-Care Ultrasound: A Retrospective Chart Review.

BACKGROUND: Incidental findings are unrelated to a patient's complaint, found on diagnostic imaging, such as point-of-care ultrasound (POCUS). Incidental findings represent potential harms to patients and may lead to increased patient anxiety and health care costs related to downstream testing and surveillance. STUDY OBJECTIVES: In this study, we aimed to calculate the rate of incidental renal cysts found by POCUS. Further, we hoped to describe how emergency physicians relay the findings to patients. Lastly, we hoped to examine if patients suffered harms in the 12 months following identification of an incidental renal cyst. METHODS: From our single-center, academic emergency department (ED), we reviewed renal POCUS images from 1000 consecutive adult ED patients to determine if there was a renal cyst. Next, we performed manual chart review to determine if patients were informed of the incidental renal cyst or suffered any patient harms. RESULTS: We found the prevalence of renal cysts to be 6.5% (95% confidence interval: 4.9%-8.4%). Those with cysts were more likely to be older compared to those without (63 ± 14 vs. 49 ± 15 years of age). Only 8% of patients had evidence that they were informed of their incidental renal cyst. No patients received a biopsy or were diagnosed with renal cell carcinoma or polycystic kidney disease. CONCLUSION: Incidental renal cysts are common and are more likely to be found in older adults. In our study, physicians infrequently informed patients of their incidental finding.

Miniplate Versus Reconstruction Bar Fixation for Oncologic Mandibular Reconstruction with Free Fibula Flaps.

BACKGROUND: Fibula free flaps (FFF) are the gold standard tissue for the reconstruction of segmental mandibular defects. A comparison of miniplate (MP) and reconstruction bar (RB)-based fixation of FFFs has been previously described in a systematic review; however, long-term, single-center studies comparing the two plating methods are lacking. The authors aim to examine the complication profile between MPs and RBs at a single tertiary cancer center. We hypothesized that increased components and a lack of rigid fixation inherent to MPs would lead to higher rates of hardware exposure/failure. METHODS: A retrospective review was performed from a prospectively maintained database at Memorial Sloan Kettering Cancer Center. All patients who underwent FFF-based reconstruction of mandibular defects between 2015 and 2021 were included. Data on patient demographics, medical risk factors, operative indications, and chemoradiation were collected. The primary outcomes of interest were perioperative flap-related complications, long-term union rates, osteoradionecrosis (ORN), return to the operating room (OR), and hardware exposure/failure. Recipient site complications were further stratified into two groups: early (<90 days) and late (>90 days). RESULTS: In total, 96 patients met the inclusion criteria (RB = 63, MP = 33). Patients in both groups were similar with respect to age, presence of comorbidities, smoking history, and operative characteristics. The mean follow-up period was 17.24 months. In total, 60.6 and 54.0% of patients in the MP and RB cohorts received adjuvant radiation, respectively. There were no differences in rates of hardware failure overall; however, in patients with an initial complication after 90 days, MPs had significantly higher rates of hardware exposure (3 vs. 0, p = 0.046). CONCLUSION: MPs were found to have a higher risk of exposed hardware in patients with a late initial recipient site complication. It is possible that improved fixation with highly adaptive RBs designed by computer-aided design/manufacturing technology explains these results. Future studies are needed to assess the effects of rigid mandibular fixation on patient-reported outcome measures in this unique population.

Quality of Life Outcomes after Free Fibula Flap Reconstruction of Mandibular Defects: A Longitudinal Examination.

BACKGROUND: A comprehensive understanding of changes in health-related quality of life after head and neck cancer surgery is necessary for effective preoperative counseling. The goal of this study was to perform a longitudinal analysis of postoperative quality of life outcomes after fibula free flap (FFF) mandible reconstruction. METHODS: A retrospective review was performed for all patients who underwent oncologic mandible reconstruction with an FFF between 2000 and 2021. Completion of at least one postoperative FACE-Q questionnaire was necessary for inclusion. FACE-Q scores were divided into five time periods for analysis. Functional outcomes measured with speech language pathology (SLP) assessments and tracheostomy and gastrostomy tube status were analyzed at three time points. RESULTS: One hundred and nine patients were included. Of these, 68 patients also had at least one SLP assessment. All outcomes as measured by the various FACE-Q scales did not improve significantly from the immediate postoperative time point to the last evaluated time point (p > 0.05). SLP functional outcomes showed some deterioration over time, but these were not significant (p > 0.05). The percentage of patients who required a tracheostomy (18 to 2%, p = 0.002) or gastrostomy tube (25 to 11%, p = 0.035) decreased significantly from the immediate postoperative time point to the last evaluated time point. CONCLUSION: Subjective quality of life outcomes do not change significantly with time after oncologic FFF mandible reconstruction. Reconstructive surgeons can use these results to help patients establish appropriate and achievable quality of life goals after surgery. Further studies are warranted to elucidate the impact of specific relevant clinical variables on postoperative quality of life.

Strategies to avoid mastectomy skin-flap necrosis during nipple-sparing mastectomy.

BACKGROUND: Nipple-sparing mastectomy is associated with a higher risk of mastectomy skin-flap necrosis than conventional skin-sparing mastectomy. There are limited prospective data examining modifiable intraoperative factors that contribute to skin-flap necrosis after nipple-sparing mastectomy. METHODS: Data on consecutive patients undergoing nipple-sparing mastectomy between April 2018 and December 2020 were recorded prospectively. Relevant intraoperative variables were documented by both breast and plastic surgeons at the time of surgery. The presence and extent of nipple and/or skin-flap necrosis was documented at the first postoperative visit. Necrosis treatment and outcome was documented at 8-10 weeks after surgery. The association of clinical and intraoperative variables with nipple and skin-flap necrosis was analysed, and significant variables were included in a multivariable logistic regression analysis with backward selection. RESULTS: Some 299 patients underwent 515 nipple-sparing mastectomies (54.8 per cent (282 of 515) prophylactic, 45.2 per cent therapeutic). Overall, 23.3 per cent of breasts (120 of 515) developed nipple or skin-flap necrosis; 45.8 per cent of these (55 of 120) had nipple necrosis only. Among 120 breasts with necrosis, 22.5 per cent had superficial, 60.8 per cent had partial, and 16.7 per cent had full-thickness necrosis. On multivariable logistic regression analysis, significant modifiable intraoperative predictors of necrosis included sacrificing the second intercostal perforator (P = 0.006), greater tissue expander fill volume (P < 0.001), and non-lateral inframammary fold incision placement (P = 0.003). CONCLUSION: Modifiable intraoperative factors that may decrease the likelihood of necrosis after nipple-sparing mastectomy include incision placement in the lateral inframammary fold, preserving the second intercostal perforating vessel, and minimizing tissue expander fill volume.

Long-term exclusion of invasive ungulates alters tree recruitment and functional traits but not total forest carbon.

Forests are major carbon (C) sinks, but their ability to sequester C and thus mitigate climate change, varies with the environment, disturbance regime, and biotic interactions. Herbivory by invasive, nonnative ungulates can have profound ecosystem effects, yet its consequences for forest C stocks remain poorly understood. We determined the impact of invasive ungulates on C pools, both above- and belowground (to 30 cm), and on forest structure and diversity using 26 paired long-term (>20 years) ungulate exclosures and adjacent unfenced control plots located in native temperate rainforests across New Zealand, spanning 36-41° S. Total ecosystem C was similar between ungulate exclosure (299.93 ± 25.94 Mg C ha-1 ) and unfenced control (324.60 ± 38.39 Mg C ha-1 ) plots. Most (60%) variation in total ecosystem C was explained by the biomass of the largest tree (mean diameter at breast height [dbh]: 88 cm) within each plot. Ungulate exclusion increased the abundance and diversity of saplings and small trees (dbh ≥2.5, <10 cm) compared with unfenced controls, but these accounted for ~5% of total ecosystem C, demonstrating that a few, large trees dominate the total forest ecosystem C but are unaffected by invasive ungulates at a timescale of 20-50 years. However, changes in understory C pools, species composition, and functional diversity did occur following long-term ungulate exclusion. Our findings suggest that, although the removal of invasive herbivores may not affect total forest C at the decadal scale, major shifts in the diversity and composition of regenerating species will have longer term consequences for ecosystem processes and forest C.

Decreasing length of stay in breast reconstruction patients: A national analysis of 2019-2020.

BACKGROUND: The effects of COVID-19 on breast reconstruction included shifts toward alloplastic reconstruction methods to preserve hospital resources and minimize COVID exposures. We examined the effects of COVID-19 on breast reconstruction hospital length of stay (LOS) and subsequent early postoperative complication rates. METHODS: Using the National Surgical Quality Improvement Program, we examined female patients who underwent mastectomy with immediate breast reconstruction from 2019 to 2020. We compared postoperative complications across 2019-2020 for alloplastic and autologous reconstruction patients. We further performed subanalysis of 2020 patients based on LOS. RESULTS: Both alloplastic and autologous reconstruction patients had shorter inpatient stays. Regarding the alloplastic 2019 versus 2020 cohorts, complication rates did not differ (p > 0.05 in all cases). Alloplastic patients in 2020 with longer LOS had more unplanned reoperations (p < 0.001). Regarding autologous patients in 2019 versus 2020, the only complication increasing from 2019 to 2020 was deep surgical site infection (SSI) (2.0% vs. 3.6%, p = 0.024). Autologous patients in 2020 with longer LOS had more unplanned reoperations (p = 0.007). CONCLUSIONS: In 2020, hospital LOS decreased for all breast reconstruction patients with no complication differences in alloplastic patients and a slight increase in SSIs in autologous patients. Shorter LOS may lead to improved satisfaction and lower healthcare costs with low complication risk, and future research should examine the potential relationship between LOS and these outcomes.

Plant expression of NifD protein variants resistant to mitochondrial degradation.

To engineer Mo-dependent nitrogenase function in plants, expression of the structural proteins NifD and NifK will be an absolute requirement. Although mitochondria have been established as a suitable eukaryotic environment for biosynthesis of oxygen-sensitive enzymes such as NifH, expression of NifD in this organelle has proven difficult due to cryptic NifD degradation. Here, we describe a solution to this problem. Using molecular and proteomic methods, we found NifD degradation to be a consequence of mitochondrial endoprotease activity at a specific motif within NifD. Focusing on this functionally sensitive region, we designed NifD variants comprising between one and three amino acid substitutions and distinguished several that were resistant to degradation when expressed in both plant and yeast mitochondria. Nitrogenase activity assays of these resistant variants in Escherichia coli identified a subset that retained function, including a single amino acid variant (Y100Q). We found that other naturally occurring NifD proteins containing alternate amino acids at the Y100 position were also less susceptible to degradation. The Y100Q variant also enabled expression of a NifD(Y100Q)-linker-NifK translational polyprotein in plant mitochondria, confirmed by identification of the polyprotein in the soluble fraction of plant extracts. The NifD(Y100Q)-linker-NifK retained function in bacterial nitrogenase assays, demonstrating that this polyprotein permits expression of NifD and NifK in a defined stoichiometry supportive of activity. Our results exemplify how protein design can overcome impediments encountered when expressing synthetic proteins in novel environments. Specifically, these findings outline our progress toward the assembly of the catalytic unit of nitrogenase within mitochondria.

Outcomes and Perioperative Risk Factors after Oncologic Free-Flap Scalp Reconstruction.

BACKGROUND: Little is known about the risk factors associated with complications after free flap scalp reconstruction. The purpose of this study was to identify patient, scalp defect, and flap characteristics associated with increased risk of surgical complications. METHODS: A retrospective study was performed of free-flap scalp reconstruction in oncologic patients at Memorial Sloan Kettering Cancer Center from 2002 to 2017. Data collection included patient, defect, flap, and complication characteristics. Complications were classified into major, defined as complications requiring surgical intervention, and minor, defined as complications requiring conservative treatment. Risk factors and outcome variables were compared using chi-square with Fisher's exact test. RESULTS: A total of 63 free flaps to the scalp in 58 patients were performed; average follow-up was 3.5 years. Most flaps were muscle-only or musculocutaneous. One-third of patients with free flaps experienced complications (n = 21, 15 major and 6 minor). Examining risk factors for complications, patients with cardiovascular disease were nearly three times more likely to have suffered a major complication than patients without cardiovascular disease (36.7 vs. 12.1%, p = 0.04). This was the only significant risk factor noted. Perioperative radiotherapy, prior scalp surgery, flap type, and recipient vessel selection were found to be nonsignificant risk factors. CONCLUSION: Cardiovascular disease may be a significant marker of risk for major complications in patients undergoing free-flap reconstruction of the scalp. This information should be used to help guide perioperative counseling and decision making in this challenging patient population.