Dynamics of the Boundary Layer in Pulsed CO2 Electrolysis.

Electrochemical reduction of CO2 poses a vast potential to contribute to a defossilized industry. Despite tremendous developments within the field, mass transport limitations, carbonate salt formation, and electrode degradation mechanisms still hamper the process performance. One promising approach to tweak CO2 electrolysis beyond today's limitations is pulsed electrolysis with potential cycling between an operating and a regeneration mode. Here, we rigorously model the boundary layer at a silver electrode in pulsed operation to get profound insights into the dynamic reorganization of the electrode microenvironment. In our simulation, pulsed electrolysis leads to a significant improvement of up to six times higher CO current density and 20 times higher cathodic energy efficiency when pulsing between -1.85 and -1.05 V vs SHE compared to constant potential operation. We found that elevated reactant availability in pulsed electrolysis originates from alternating replenishment of CO2 by diffusion and not from pH-induced carbonate and bicarbonate conversion. Moreover, pulsed electrolysis substantially promotes carbonate removal from the electrode by up to 83 % compared to constant potential operation, thus reducing the risk of salt formation. Therefore, this model lays the groundwork for an accurate simulation of the dynamic boundary layer modulation, which can provide insights into manifold electrochemical conversions.

Micromodel of a Gas Diffusion Electrode Tracks In-Operando Pore-Scale Wetting Phenomena.

Utilizing carbon dioxide (CO2 ) as a resource for carbon monoxide (CO) production using renewable energy requires electrochemical reactors with gas diffusion electrodes that maintain a stable and highly reactive gas/liquid/solid interface. Very little is known about the reasons why gas diffusion electrodes suffer from unstable long-term operation. Often, this is associated with flooding of the gas diffusion electrode (GDE) within a few hours of operation. A better understanding of parameters influencing the phase behavior at the electrolyte/electrode/gas interface is necessary to increase the durability of GDEs. In this work, a microfluidic structure with multi-scale porosity featuring heterogeneous surface wettability to realistically represent the behavior of conventional GDEs is presented. A gas/liquid/solid phase boundary was established within a conductive, highly porous structure comprising a silver catalyst and Nafion binder. Inoperando visualization of wetting phenomena was performed using confocal laser scanning microscopy (CLSM). Non-reversible wetting, wetting of hierarchically porous structures and electrowetting were observed and analyzed. Fluorescence lifetime imaging microscopy (FLIM) enabled the observation of reactions on the model electrode surface. The presented methodology enables the systematic evaluation of spatio-temporally evolving wetting phenomena as well as species characterization for novel catalyst materials under realistic GDE configurations and process parameters.

A scalable bubble-free membrane aerator for biosurfactant production.

The bioeconomy is a paramount pillar in the mitigation of greenhouse gas emissions and climate change. Still, the industrialization of bioprocesses is limited by economical and technical obstacles. The synthesis of biosurfactants as advanced substitutes for crude-oil-based surfactants is often restrained by excessive foaming. We present the synergistic combination of simulations and experiments towards a reactor design of a submerged membrane module for the efficient bubble-free aeration of bioreactors. A digital twin of the combined bioreactor and membrane aeration module was created and the membrane arrangement was optimized in computational fluid dynamics studies with respect to fluid mixing. The optimized design was prototyped and tested in whole-cell biocatalysis to produce rhamnolipid biosurfactants from sugars. Without any foam formation, the new design enables a considerable higher space-time yield compared to previous studies with membrane modules. The design approach of this study is of generic nature beyond rhamnolipid production.

Quantifying Patient Engagement in Total Joint Arthroplasty Using Digital Application-Based Technology.

BACKGROUND: Digital patient engagement has been suggested as a mean to increase patient activation and patient satisfaction after total joint arthroplasty. The purpose of this study was to assess patient engagement with application-based educational tools and to explore what content was most useful to patients in the perioperative period surrounding total hip arthroplasty (THA) and total knee arthroplasty (TKA), respectively. METHODS: Patients undergoing THA and TKA between October 2017 and January 2020 were enrolled to use an application-based digital technology. The App provides comprehensive patient education using a series of modules delivered at set intervals preoperatively and postoperatively. Patient engagement was defined as patients viewing at least one time the modules that were sent, or marking them as completed. Patient satisfaction was assessed using an in-application survey. RESULTS: Complete data were available on 207 patients of which 95 (46%) underwent THA and 112 (54%) underwent TKA. The average age was 60 years. 54% with patients invited to the program completed registration. An average compliance rate of 48% (41 modules engaged out of 83) was observed. Of all modules completed, the top three most popular categories included physical therapy/exercise videos, health literacy, and anxiety/stress/pain management. The least viewed category was nutrition planning and education. CONCLUSION: When presented educational material related to THA and TKA, patients had a high rate of compliance. Digital technology platforms provide a scalable, meaningful approach to engaging patients throughout the continuum of joint replacement care and may serve as a cost-effective adjunct to traditional methods.

Taxonomy and model for valuing the contribution of digital water meters to sustainability objectives.

Water security is an issue across the world as communities face ageing infrastructure, population increases and climate change. The application of digital water metering (DWM) to properties has had a demonstrable impact on water savings at the property and network levels, on efficiencies within water utilities, as well as on improvements to customer satisfaction scores. Gathering and processing near-real-time water usage data is very important for both end-users and utilities, as well as demand and supply management planning. The potential contribution of DWM to the three pillars of water sustainability (environmental, economic development and social equity) is often overlooked. In Australia and other jurisdictions water utilities are facing up to the challenge of climate change. However, business cases promoting DWM are often unsuccessful because the benefit side falls short of the cost side. This study sought to identify possible DWM benefits not previously considered through an extensive review of academic and industry literature, and then to view those benefits through the lens of sustainability. The 77 identified benefits of DWM were catalogued and a taxonomy was created. The study elicited the opinions of experts, before quantifying them, thus identifying two distinct contexts of benefit value; subsequently, it surveyed the views of customers and developed a stochastic model of benefit value. The model, named DWM360, was applied to the project data of a large metropolitan water utility in Australia to model their DWM proposal for cost savings, contribution to sustainability and uplift in customer satisfaction. This paper presents a novel focus on how the benefits of DWM assist water sustainability. It considers differing social norms that impact consumer acceptance of changes in metering and water charges. The study will be of interest to researchers as well as practitioners looking to identify sustainability aspects of DWM.

Posterior capsule injection of local anesthetic for post-operative pain control after ACL reconstruction: a prospective, randomized trial.

PURPOSE: Alternative modalities to optimize pain control after anterior cruciate ligament reconstruction (ACLR) are continually being explored. The purpose of this study was to compare femoral nerve block (FNB) only vs FNB with posterior capsule injection (PCI) of the knee for pain control in patients undergoing ACLR. METHODS: Patients undergoing primary ACLR were randomized to receive either FNB only or FNB with PCI. Following surgery, patient's pain was evaluated in the postoperative care unit (PACU) and at home for 4 days. Pain levels were measured via visual analog scale (VAS) and calculating opioid consumption. Outcomes of interest included postoperative pain levels and opioid consumption. RESULTS: A total of 42 patients were evaluated, with 21 patients randomized to each study arm. Outcomes showed significant pain reduction in both anterior and posterior knee VAS scores in the PACU in those that received PCI (anterior VAS: 39.6 vs 21.3 (SD = 12.9), p < 0.01; posterior VAS: 25.4 vs 15.3 (SD = 8.05), p = 0.01). Moreover, the PCI group also showed significantly less opioid consumption compared to FNB only (23.5 vs 17.4 pills, p = 0.03). There were no differences found in pain scores between groups in home VAS sores. CONCLUSIONS: These finding suggest the use of arthroscopically assisted injection of local anesthetic to the posterior capsule of the knee significantly reduces early post-operative pain and dramatically reduces the number of opoid medication taken after ACLR. LEVEL OF EVIDENCE: Prospective, randomized, control trial, Level I.

Single-Shot Femoral Nerve Block Does Not Cause Long-Term Strength and Functional Deficits Following Anterior Cruciate Ligament Reconstruction.

PURPOSE: To determine if patients treated with a single-shot femoral nerve block have strength and functional deficits at 9-month follow-up. METHODS: Forty-three patients who underwent primary anterior cruciate ligament reconstructions were randomized to receive either a preoperative single-shot femoral nerve block or local infiltration anesthesia for primary pain control. All patients underwent a standardized comprehensive rehabilitation program postoperatively. Isokinetic strength and function was tested using a Biodex machine at 9 months or more postoperatively comparing the operative and nonoperative extremity. RESULTS: No significant difference in strength was found at an average of 10.6 months postoperatively (range, 9-15 months) between the femoral nerve block and control groups. In comparing strength deficits, we found no difference in slow isokinetic extension strength (22.4% vs 27.8%, P = .51), fast isokinetic extension strength (18.5% vs 12.5%, P = .41), slow isokinetic flexion strength (11.0% vs 15.1%, P = .55), and fast isokinetic flexion strength (8.2% vs 4.9%, P = .56) in the femoral nerve block versus control groups, respectively. In terms of functional outcomes, there also was no difference in deficits for single-leg hop distance (P = .12), timed single-leg hop (P = .74), and single-leg triple hop distance (P = .94). Maximal strength noted to be within 15% of the contralateral limb was achieved in 40% of patients and maximal function in 63% of patients at an average of 10.6 months postoperatively. A 13% complication rate was found in patients who received a femoral nerve block (1 with prolonged quadriceps inhibition and 2 with prolonged sensory disturbances). CONCLUSIONS: Our study found a 13% motor/sensory complication rate in patients who underwent femoral nerve block for pain control after anterior cruciate ligament reconstruction. Although these deficits may persist, they are not permanent and are not different when compared with controls at 9-month follow-up. However, maximal strength and function are not fully restored at normal return to play time and rehabilitation should continue long term to maximize recovery. LEVEL OF EVIDENCE: Level I, prospective randomized trial.

Return to play after shoulder instability in National Football League athletes.

HYPOTHESIS: We hypothesized that National Football League (NFL) players sustaining a shoulder destabilizing injury could return to play (RTP) successfully at a high rate regardless of treatment type. METHODS: We identified and evaluated 83 NFL players who sustained an in-season shoulder instability event while playing in the NFL. NFL RTP, incidence of surgery, time to RTP, recurrent instability events, seasons/games played after the injury, and demographic data were collected. Overall RTP was determined, and players who did and did not undergo operative repair were compared. RESULTS: Ninety-two percent of NFL players returned to NFL regular season play at a median of 0.0 weeks in those sustaining a shoulder subluxation and 3.0 weeks in those sustaining a dislocation who did not undergo surgical repair (P = .029). Players who underwent operative repair returned to play at a median of 39.3 weeks. Forty-seven percent of players had a recurrent instability event. For players who were able to RTP, those who underwent surgical repair (31%) had a lower recurrence rate (26% vs. 55%, P = .021) and longer interval between a recurrent instability event after RTP (14.7 vs. 2.5 weeks, P = .050). CONCLUSION: There is a high rate of RTP after shoulder instability events in NFL players. Players who sustain shoulder subluxations RTP faster but are more likely to experience recurrent instability than those with shoulder dislocations. Surgical stabilization of the shoulder after an instability event decreases the chances of a second instability event and affords a player a greater interval between the initial injury and a recurrent event.

Ultrasound evaluation of the ulnar collateral ligament of the elbow: Which method is most reproducible?

INTRODUCTION: The ulnar collateral ligament (UCL) is an important medial stabilizer of the elbow, particularly in overhead-throwing athletes. However, there is no universally accepted method for evaluating UCL thickness with ultrasound (US). OBJECTIVE: To assess reproducibility of previously published methods, as well as a modified technique, for evaluating the UCL via US. We hypothesize that a modified technique would show greater reproducibility. MATERIAL AND METHODS: Using US, the thickness of the UCL in 50 volunteers was measured by two musculoskeletal trained radiologists using two different measurement techniques. The techniques utilized were as described by Nazarian and Jacobson/Ward (JW). Technique measurements were evaluated using interclass correlation coefficients (ICC) to determine the reproducibility of each method. Twenty-eight of the subjects also underwent measurement via a modified JW technique, measured perpendicular to the ligament rather than the frame of imaging. This technique was also evaluated with ICC values. RESULTS: The ICC value for the Nazarian technique was 0.82 (very good) and 0.51 (moderate) for the JW technique. When using the modified JW technique, we found an ICC value of 0.84 (very good). Mean ligament thickness was greatest with the Nazarian technique, 6.41 mm, with the JW technique measuring 1.86 mm and the modified technique measuring 1.38 mm. CONCLUSION: US assessment of UCL thickness by all three measurement techniques are reproducible. The JW technique had less interobserver agreement when compared to the Nazarian method, whereas the modified JW technique had greater reproducibility compared to the JW technique and similar to the Nazarian technique.

Relative individual workload changes may be a risk factor for rerupture of ulnar collateral ligament reconstruction.

BACKGROUND: With an increasing number of Major League Baseball (MLB) players undergoing ulnar collateral ligament (UCL) reconstruction, there remains limited literature on appropriate post-reconstruction workload management to limit the risk of reinjury. METHODS: A total of 28 MLB pitchers who underwent primary UCL reconstruction surgery and subsequently required revision reconstruction were identified and compared with 137 MLB pitchers who underwent primary reconstruction but did not later require revision surgery. Games pitched, pitch counts, and innings pitched were evaluated and compared 3 years before and after primary reconstruction. Results were then compared between groups. RESULTS: Pitchers who later required revision increased their games pitched by 14.1% after reconstruction whereas the no-revision group pitched 13.6% fewer games than before reconstruction (P < .01). Inning workload was reduced by 9.8% after surgery (89.8 innings after vs 99.6 innings before) for the revision group compared with the no-revision group, which threw 26% fewer innings after surgery (86.3 innings after vs 116.7 innings before) (P = .05). In addition, the revision group pitched 6.6% more pitches after reconstruction, 1138.9 pitches, compared with before reconstruction, 1068.6 pitches. Pitchers who did not require revision, in contrast, pitched 19.6% fewer pitches after reconstruction than before reconstruction (P = .08). CONCLUSIONS: This study's findings suggest that MLB pitchers who require revision UCL reconstruction after returning to play following primary UCL reconstruction pitch at or above their pre-primary UCL reconstruction workload whereas control pitchers who do not require revision pitch significantly less, below their pre-primary UCL reconstruction workload.

Major League pitching workload after primary ulnar collateral ligament reconstruction and risk for revision surgery.

BACKGROUND: Literature has attempted to correlate pitching workload with risk of ulnar collateral ligament (UCL) injury; however, limited data are available in evaluating workload and its relationship with the need for revision reconstruction in Major League Baseball (MLB) pitchers. METHODS: We identified 29 MLB pitchers who underwent primary UCL reconstruction surgery and subsequently required revision reconstruction and compared them with 121 MLB pitchers who underwent primary reconstruction but did not later require revision surgery. Games pitched, pitch counts, and innings pitched were evaluated and compared for the seasons after returning from primary reconstruction and for the last season pitched before undergoing revision surgery. RESULTS: The difference in workload between pitchers who did and did not require revision reconstruction was not statistically significant in games pitched, innings pitched, and MLB-only pitch counts. The one significant difference in workload was in total pitch counts (combined MLB and minor league), with the pitchers who required revision surgery pitching less than those who did not (primary: 1413.6 pitches vs. revision: 959.0 pitches, P = .04). In addition, pitchers who required revision surgery underwent primary reconstruction at an early age (22.9 years vs. 27.3 years, P < .001) and had less MLB experience (1.5 years vs. 5.0 years, P < .001). CONCLUSIONS: There is no specific number of pitches, innings, or games that place a pitcher at an increase risk for injury after primary UCL reconstruction. However, correlations of risk may be younger age and less MLB experience at the time of the primary reconstruction.

Liposomal Bupivacaine Versus Femoral Nerve Block for Pain Control After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Trial.

PURPOSE: To compare femoral nerve block (FNB) versus local liposomal bupivacaine (LB) for pain control in patients undergoing anterior cruciate ligament (ACL) reconstruction. METHODS: Eighty-five patients undergoing primary ACL reconstruction were assessed for participation. We performed a prospective randomized trial in accordance with the CONSORT (Consolidated Standards of Reporting Trials) 2010 statement. The study arms included either intraoperative local infiltration of LB (20 mL of bupivacaine/10 mL of saline solution) or preoperative FNB with a primary outcome of postoperative pain levels (visual analog scale) for 4 days. Secondary outcomes assessed included opioid consumption (intravenous morphine equivalents), hours slept, patient satisfaction, and calls to the physician. Randomization was by a computerized algorithm. The observer was blinded and the patient was not blinded to the intervention. RESULTS: One patient declined participation; 2 patients were excluded after randomization. A total of 82 patients were analyzed. Outcomes showed a significant increase in pain in the LB group between 5 and 8 hours postoperatively (mean ± standard deviation, 6.3 ± 2.0 versus 4.8 ± 2.6; P = .01). There were no significant differences between the groups in mean daily pain levels, morphine equivalents, or patient satisfaction when we controlled for graft type, age, body mass index, and sex. Patients receiving an FNB had a nonsignificant increase in number of sleep disturbances on the day of surgery (mean ± standard deviation, 4.4 ± 3.7 v 3.1 ± 2.1; P = .09) and were more likely to call their doctor the following day because of pain (29% v 8%, P = .04). Six patients in the FNB group had either prolonged quadriceps inhibition or sensory disturbance. One patient in the LB group required reoperation for a flexion contracture. CONCLUSIONS: An increase in acute postoperative pain was found with LB compared with FNB for post-ACL reconstruction pain control. After the acute postoperative period, there were no significant differences in opioid consumption or pain control. The occurrence of nerve irritation postoperatively was found to be higher in the FNB group. LEVEL OF EVIDENCE: Level I, prospective randomized trial.

Dark-Field Scanning Transmission Ion Microscopy via Detection of Forward-Scattered Helium Ions with a Microchannel Plate.

A microchannel plate was used as an ion sensitive detector in a commercial helium ion microscope (HIM) for dark-field transmission imaging of nanomaterials, i.e. scanning transmission ion microscopy (STIM). In contrast to previous transmission HIM approaches that used secondary electron conversion holders, our new approach detects forward-scattered helium ions on a dedicated annular shaped ion sensitive detector. Minimum collection angles between 125 mrad and 325 mrad were obtained by varying the distance of the sample from the microchannel plate detector during imaging. Monte Carlo simulations were used to predict detector angular ranges at which dark-field images with atomic number contrast could be obtained. We demonstrate atomic number contrast imaging via scanning transmission ion imaging of silica-coated gold nanoparticles and magnetite nanoparticles. Although the resolution of STIM is known to be degraded by beam broadening in the substrate, we imaged magnetite nanoparticles with high contrast on a relatively thick silicon nitride substrate. We expect this new approach to annular dark-field STIM will open avenues for more quantitative ion imaging techniques and advance fundamental understanding of underlying ion scattering mechanisms leading to image formation.

Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.

BACKGROUND: The number of Major League Baseball (MLB) pitchers requiring ulnar collateral ligament (UCL) reconstructions is increasing. Recent literature has attempted to correlate specific stresses placed on the throwing arm to risk for UCL injury, with limited results. METHODS: Eighty-three MLB pitchers who underwent primary UCL reconstruction were evaluated. Pitching velocity and percent of pitch type thrown (fastball, curve ball, slider, and change-up) were evaluated 2 years before and after surgery. Data were compared with control pitchers matched for age, position, size, innings pitched, and experience. RESULTS: The evaluation of pitch velocity compared with matched controls found no differences in pre-UCL reconstruction pitch velocities for fastballs (91.5 vs. 91.2 miles per hour [mph], P = .69), curveballs (78.2 vs. 77.9 mph, P = .92), sliders (83.3 vs. 83.5 mph, P = .88), or change-ups (83.9 vs. 83.8 mph, P = .96). When the percentage of pitches thrown was evaluated, UCL reconstructed pitchers pitch significantly more fastballs than controls (46.7% vs. 39.4%, P = .035). This correlated to a 2% increase in risk for UCL injury for every 1% increase in fastballs thrown. Pitching more than 48% fastballs was a significant predictor of UCL injury, because pitchers over this threshold required reconstruction (P = .006). CONCLUSION: MLB pitchers requiring UCL reconstruction do not pitch at higher velocities than matched controls, and pitch velocity does not appear to be a risk factor for UCL reconstruction. However, MLB pitchers who pitch a high percentage of fastballs may be at increased risk for UCL injury because pitching a higher percent of fastballs appears to be a risk factor for UCL reconstruction.

Liposomal bupivacaine versus interscalene nerve block for pain control after shoulder arthroplasty: a prospective randomized trial.

HYPOTHESIS: Our hypothesis was that in patients undergoing shoulder arthroplasty, a prospective randomized trial would find no significant differences in average daily pain scores of those treated with interscalene nerve block (INB) vs. local liposomal bupivacaine (LB). METHODS: Sixty patients undergoing primary shoulder arthroplasty were assessed for eligibility. Study arms included either intraoperative local infiltration of LB (20 mL bupivacaine/20 mL saline) or preoperative INB, with a primary outcome of postoperative average daily visual analog scale scores for 4 days. Secondary outcomes assessed included opioid consumption, length of stay, and complications. Randomization was by a computerized algorithm. Only the observer was blinded to the intervention. RESULTS: Three patients were excluded, all before randomization. A total of 57 patients were analyzed. Outcomes showed a significant increase in pain in the LB group between 0 and 8 hours postoperatively (mean [standard deviation] 5.3 [2.2] vs. 2.5 [3.0]; P = .001). A significant increase in intravenous morphine equivalents was found in the INB group at 13 to 16 hours (mean [standard deviation] 1.2 [0.9] vs. 0.6 [0.7]; P = .01). No significant differences were found in any variable after postoperative day 0 between the 2 groups. CONCLUSION: An increase in early postoperative pain on the day of surgery was found with LB, whereas the INB group required more narcotics at the end of the day. After the day of surgery, there were no significant differences found in any variables. These findings suggest that LB provides similar overall pain relief as INB, with no increase in complications or length of stay and a decrease in narcotic requirements on the day of surgery.

Evidence-Based Management of Vascular Malformations.

Vascular malformations of the head and neck are complex lesions that are notoriously difficult to manage. Treatment of these lesions often requires a multispecialty and multimodal approach. In the modern era of evidence-based medicine, it has become imperative for clinicians to incorporate evidence-based treatment algorithms into their everyday practices. With general widespread inundation of the literature with levels IV and V clinical evidence, however, it is often difficult to draw meaningful conclusions that can be practically applied to the clinical question at hand. When asking how best to manage the most common vascular malformations, we are faced with this large volume of lower level studies conducted in drastically different ways without consistency in outcomes reporting, thus making direct comparison nearly impossible. Furthermore, much of the evidence shows mixed results, adding to confusion over what the optimal evidence-based treatment approaches truly are. In attempt to derive consensus from available literature discussing the management of vascular malformations, we reviewed the current literature detailing modern-day treatment approaches for lymphatic malformations, venous malformations, and arteriovenous malformations of the head and neck.

Pre- and Postseason Dynamic Ultrasound Evaluation of the Pitching Elbow.

PURPOSE: To use ultrasound imaging to document changes over time (i.e., preseason v postseason) in the pitching elbow of high school baseball pitchers. METHODS: Twenty-two high school pitchers were prospectively followed. Pitchers were evaluated after a 2-month period of relative arm rest via preseason physical exams, dynamic ultrasound imaging of their throwing elbow, and the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) assessment. Players were reevaluated within 1 week of their last game. Dynamic ultrasound images were then randomized, blinded to testing time point, and evaluated by 2 fellowship-trained musculoskeletal radiologists. RESULTS: Average pitcher age was 16.9 years. Average pitches thrown was 456.5, maximum velocity 77.7 mph, games pitched 7.3, and days off between starts 6.6. From preseason to postseason, there were significant increases in ulnar collateral ligament (UCL) thickness (P = .02), ulnar nerve cross-sectional area (P = .001), UCL substance heterogeneity (P = .001), and QuickDASH scores (P = .03). In addition, there was a nonsignificant increase in loaded ulnohumeral joint space (P = .10). No pitchers had loose bodies on preseason exam, while 3 demonstrated loose bodies postseason. The increase in UCL thickness was significantly associated with the number of bullpen sessions per week (P = .01). The increase in ulnar nerve cross-sectional area was significantly associated with the number of pitches (P = .04), innings pitched (P = .01), and games pitched (P = .04). CONCLUSIONS: The stresses placed on the elbow during only one season of pitching create adaptive changes to multiple structures about the elbow including UCL heterogeneity and thickening, increased ulnohumeral joint space laxity, and enlarged ulnar nerve cross-sectional area. LEVEL OF EVIDENCE: Level II prospective observational study.

The effects of medial ulnar collateral ligament reconstruction on Major League pitching performance.

BACKGROUND: Medial ulnar collateral ligament (MUCL) reconstruction is commonly performed on Major League Baseball (MLB) pitchers. Previous studies have reported that most pitchers return to presurgical statistical performance levels after MUCL reconstruction. METHODS: Pitching performance data--specifically, earned run average (ERA), walks and hits per inning pitched (WHIP), winning percentage, and innings pitched--were acquired for 168 MLB pitchers who had undergone MUCL reconstruction. These data were averaged over the 3 years before surgery and the 3 years after surgery and also acquired from 178 age-matched, uninjured MLB pitchers. RESULTS: Of the pitchers who had MUCL reconstruction surgery, 87% returned to MLB pitching. However, compared with presurgical data, pitching performance declined in terms of ERA (P = .001), WHIP (P = .011), and innings pitched (P = .026). Pitching performance also declined in the season before the surgery compared with previous years (ERA, P = .014; WHIP, P = .036; innings pitched, P < .001; winning percentage, P = .004). Compared with age-matched control pitchers, the MUCL reconstruction pitchers had significantly more major league experience at the same age (P < .001). CONCLUSION: MUCL reconstruction allows most players to return to pitching at the major league level. However, after MUCL reconstruction, there is a statistically significant decline in pitching performance. There appears to be a statistically significant decline in pitching performance the year before reconstructive surgery, and this decline is also a risk factor for requiring surgery. In addition, there is an increased risk of MUCL reconstruction for pitchers who enter the major leagues at a younger age.

Pure-Water-Fed Forward-Bias Bipolar Membrane CO2 Electrolyzer.

Coupling renewable electricity to reduce carbon dioxide (CO2) electrochemically into carbon feedstocks offers a promising pathway to produce chemical fuels sustainably. While there has been success in developing materials and theory for CO2 reduction, the widespread deployment of CO2 electrolyzers has been hindered by challenges in the reactor design and operational stability due to CO2 crossover and (bi)carbonate salt precipitation. Herein, we design asymmetrical bipolar membranes assembled into a zero-gap CO2 electrolyzer fed with pure water, solving both challenges. By investigating and optimizing the anion-exchange-layer thickness, cathode differential pressure, and cell temperature, the forward-bias bipolar membrane CO2 electrolyzer achieves a CO faradic efficiency over 80% with a partial current density over 200 mA cm-2 at less than 3.0 V with negligible CO2 crossover. In addition, this electrolyzer achieves 0.61 and 2.1 mV h-1 decay rates at 150 and 300 mA cm-2 for 200 and 100 h, respectively. Postmortem analysis indicates that the deterioration of catalyst/polymer-electrolyte interfaces resulted from catalyst structural change, and ionomer degradation at reductive potential shows the decay mechanism. All these results point to the future research direction and show a promising pathway to deploy CO2 electrolyzers at scale for industrial applications.