Left ventricular shape index and eccentricity index with ECG-gated Nitrogen-13 ammonia PET/CT in patients with myocardial infarction, ischemia, and normal perfusion.

BACKGROUND: LV geometry with shape index (SI) and eccentricity index (EI) measured by myocardial perfusion positron emission tomography/computed tomography (PET/CT) may allow the evaluation of left ventricular (LV) adverse remodeling. This first study aims to explore the relationship of SI and EI values acquired by Nitrogen-13 ammonia PET/CT in patients with normal perfusion, ischemia, and myocardial infarction. And evaluate the correlations between the variables of LV geometry, and with the variables of LV function. METHODS AND RESULTS: One hundred and forty patients who underwent an electrocardiogram (ECG)-gated PET/CT were selected and classified into 4 groups according to ischemia or infarction burden (normal perfusion, mild ischemia, moderate-severe ischemia, and infarction). The variables were automatically retrieved using dedicated software (QPS/QGS; Cedars-Sinai, Los Angeles, CA, USA). On multicomparison analysis (one-way ANOVA and Dunnett's Test), subjects in the infarction group had significant higher values of SI end-diastolic rest (P < 0.001), and stress (P = 0.003), SI end-systolic rest (P = 0.002) and stress (P < 0.001) as well as statistically significant lower values of EI rest (P < 0.001) and stress (P < 0.001) when compared with all other groups. Regarding Pearson correlation, in the infarcted group all the variables of SI and EI were significantly correlated (P < 0.001) with strong correlation coefficients (>0.60). SI end-systolic correlated significantly with the variables of LV function independently of the group of patients (P < 0.05). CONCLUSIONS: Shape and eccentricity indices differ in patients with myocardial infarction as compared to patients with ischemia or normal perfusion. This encourage further research in their potential for detecting LV adverse remodeling.

Association between right ventricular global longitudinal strain and mortality in intermediate-risk pulmonary embolism.

BACKGROUND: Right ventricular (RV) systolic dysfunction has been identified as a prognostic marker for adverse clinical events in patients presenting with acute pulmonary embolism (PE). However, challenges exist in identifying RV dysfunction using conventional echocardiography techniques. Strain echocardiography is an evolving imaging modality which measures myocardial deformation and can be used as an objective index of RV systolic function. This study evaluated RV Global Longitudinal Strain (RVGLS) in patients with intermediate risk PE as a parameter of RV dysfunction, and compared to traditional echocardiographic and CT parameters evaluating short-term mortality. METHODS: Retrospective single center cohort study of 251 patients with intermediate-risk PE between 2010 and 2018. The primary outcome was all-cause mortality at 30 days. Statistical analysis evaluated each parameter comparing survivors versus non-survivors at 30 days. Receiver operating characteristic (ROC) curves and Kaplan-Meier curves were used for comparison of the two cohorts. RESULTS: Altogether 251 patients were evaluated. Overall mortality rate was 12.4%. Utilizing an ROC curve, an absolute cutoff value of 17.7 for RVGLS demonstrated a sensitivity of 93% and specificity of 70% for observed 30-day mortality. Individuals with an RVGLS ≤17.7 had a 25 times higher mortality rate than those with RVGLS above 17.7 (HR 25.24, 95% CI = 6.0-106.4, p < .001). Area under the curve was (.855), RVGLS outperformed traditional echocardiographic parameters, CT findings, and cardiac biomarkers on univariable and multivariable analysis. CONCLUSIONS: Reduced RVGLS values on initial echocardiographic assessment of patients with intermediate-risk PE identified patients at higher risk for mortality at 30 days.

Reverse total shoulder arthroplasty with proximal bone loss: a biomechanical comparison of partially vs. fully cemented humeral stems.

BACKGROUND: The appropriate amount of cementation at the time of reverse total shoulder arthroplasty with significant proximal bone loss or resection is unknown. Extensive cementation of a humeral prosthesis makes eventual revision arthroplasty more challenging, increasing the risk of periprosthetic fracture. We analyzed the degree of subsidence and torque tolerance of humeral components undergoing standard cementation technique vs. our reduced polymethyl methacrylate (PMMA) protocol. Reduced cementation may provide sufficient biomechanical stability to resist physiologically relevant loads, while still permitting a clinically attainable torque for debonding the prosthesis. METHODS: A total of 12 cadaveric humeri (6 matched pairs) underwent resection of 5 cm of bone distal to the greater tuberosity. Each pair of humeri underwent standard humeral arthroplasty preparation followed by either cementation using a 1.5-cm PMMA sphere at a location 3 cm inferior to the porous coating or standard full stem cementation. A 6-degree-of-freedom robot was used to perform all testing. Each humeral sample underwent 200 cycles of abduction, adduction, and forward elevation while being subjected to a physiologic compression force. Next, the samples were fixed in place and subjected to an increasing torque until implant-cement separation or failure occurred. Paired t tests were used to compare mean implant subsidence vs. a predetermined 5-mm threshold, as well as removal torque in matched samples. RESULTS: Fully and partially cemented implants subsided 0.49 mm (95% CI 0.23-0.76 mm) and 1.85 mm (95% CI 0.41-3.29 mm), respectively, which were significantly less than the predetermined 5-mm threshold (P < .001 and P < .01, respectively). Removal torque between fully cemented stems was 45.22 Nm (95% CI 21.86-68.57 Nm), vs. 9.26 Nm (95% CI 2.59-15.93 Nm) for partially cemented samples (P = .021). Every fully cemented humerus fractured during implant removal vs. only 1 in the reduced-cementation group. The mean donor age in our study was 76 years (range, 65-80 years). Only 1 matched pair of humeri belonged to a female donor with comorbid osteoporosis. The fractured humerus in the partially cemented group belonged to that donor. CONCLUSION: Partially and fully cemented humeral prostheses had subsidence that was significantly less than 5 mm. Partially cemented stems required less removal torque for debonding of the component from the cement mantle. In all cases, removal of fully cemented stems resulted in humeral fracture. Reduced cementation of humeral prostheses may provide both sufficient biomechanical stability and ease of future component removal.

Water in bacterial biofilms: pores and channels, storage and transport functions.

Bacterial biofilms occur in many natural and industrial environments. Besides bacteria, biofilms comprise over 70 wt% water. Water in biofilms occurs as bound- or free-water. Bound-water is adsorbed to bacterial surfaces or biofilm (matrix) structures and possesses different Infra-red and Nuclear-Magnetic-Resonance signatures than free-water. Bound-water is different from intra-cellularly confined-water or water confined within biofilm structures and bacteria are actively involved in building water-filled structures by bacterial swimmers, dispersion or lytic self-sacrifice. Water-filled structures can be transient due to blocking, resulting from bacterial growth, compression or additional matrix formation and are generally referred to as "channels and pores." Channels and pores can be distinguished based on mechanism of formation, function and dimension. Channels allow transport of nutrients, waste-products, signalling molecules and antibiotics through a biofilm provided the cargo does not adsorb to channel walls and channels have a large length/width ratio. Pores serve a storage function for nutrients and dilute waste-products or antimicrobials and thus should have a length/width ratio close to unity. The understanding provided here on the role of water in biofilms, can be employed to artificially engineer by-pass channels or additional pores in industrial and environmental biofilms to increase production yields or enhance antimicrobial penetration in infectious biofilms.

Variable exposure to echocardiography core competencies when applying minimum recommended procedural numbers for cardiology fellows in training.

BACKGROUND: The American College of Cardiology Core Cardiovascular Training Statement (COCATS) defined echocardiography core competencies and set the minimum recommend number of echocardiograms to perform (150) and interpret (300) for independent practice in echocardiography (level 2 training). Fellows may lack exposure to key pathologies that are relatively infrequent, however, even when achieving an adequate number of studies performed and interpreted. We hypothesized that cardiology fellows would lack exposure to 1 or more cardiac pathologies related to core competencies in COCATS when performing and interpreting the minimum recommend number of studies for level 2 training. METHODS: We retrospectively reviewed 11,250 reports from consecutive echocardiograms interpreted (7,500) and performed (3,750) by 25 cardiology fellows at a University tertiary referral hospital who graduated between 2015 and 2019. The first 300 echocardiograms interpreted and the first 150 echocardiograms performed by each fellow were included in the analysis. Echocardiography reports were reviewed for cardiac pathologies relating to core competencies defined in COCATS. RESULTS: All 25 fellows lacked exposure to 1 or more cardiac pathologies related to echocardiography core competencies despite meeting COCATS minimum recommended numbers for echocardiograms performed and interpreted. Pathologies for which 1 or more fellows encountered 0 cases despite meeting the minimum recommended numbers for both echocardiograms performed and interpreted included: pericardial constriction (16/25 fellows), aortic dissection (15/25 fellows), pericardial tamponade (4/25 fellows), valvular mass/thrombus (2/25 fellows), prosthetic valve dysfunction (1/25 fellows), and cardiac chamber mass/thrombus (1/25 fellows). CONCLUSIONS: Cardiology fellows who completed the minimum recommend number of echocardiograms performed and interpreted for COCATS level 2 training frequently lacked exposure to cardiac pathologies, even in a University tertiary referral hospital setting. These data suggest that fellowship programs should monitor pathology case counts for each fellow in training, in addition to the minimum recommend number of echocardiograms defined by COCATS, to ensure competency for independent practice in echocardiography.

Team IHMC at the 2020 Cybathlon: a user-centered approach towards personal mobility exoskeletons.

BACKGROUND: The past few decades have seen rapid advancements in exoskeleton technology, with a considerable shift towards applications involving users with gait pathologies. Commercial devices from ReWalk, Ekso Bionics, and Indego, mainly designed for rehabilitation purposes, have inspired the development of many research platforms aimed at extending capabilities for use as safe and effective personal mobility devices. The 2016 Cybathlon featured an impressive demonstration of exoskeletons designed to enable mobility for individuals with spinal cord injury, however, not a single team completed every task and only two completed the stairs. Major improvements were showcased at the 2020 Cybathlon, with seven of the nine teams completing a similar set of tasks. Team IHMC built upon its silver-medal success from 2016 with an upgraded device, Quix. METHODS: Quix features several notable improvements including an additional powered degree of freedom for hip ab/adduction to laterally shift the device and reduce user effort while walking, custom-tailored cuffs and soft goods based on 3D body scans to optimize user comfort, and a streamlined testing pipeline for online tuning of gait parameters. RESULTS: Team IHMC finished in fourth place behind the teams from EPFL and Angel Robotics. Although we suffered from a considerably slower flat-ground walking speed, our pilot reported marked improvements in overall effort, comfort, and ease-of-use compared to our previous device. CONCLUSIONS: Clear progress in exoskeleton development has been exhibited since the inaugural Cybathlon, with tasks involving rough terrain, stairs, and ramps now posing little threat to most of the competitors. As a result, the layout of the powered exoskeleton course will likely undergo significant modifications to further push the devices towards suitability for personal everyday use. The current tasks do not address the issue of donning and doffing, nor do they simulate a scenario similar to maneuvering a kitchen to prepare a meal, for example. An additional limitation that may be more difficult to test in a competition setting is the required upper-body effort to manipulate the device in an effective manner.

Leaf Economics of Early- and Late-Successional Plants.

AbstractThe leaf economics spectrum ranges from cheap, short-lived leaves to expensive, long-lived leaves. Species with low leaf mass per area (LMA) and short leaf life span tend to be fast growing and shade intolerant (early successional), whereas species with high LMA and long leaf life span tend to be slow growing and shade tolerant (late successional). However, we have limited understanding of how different leaf mass components (e.g., metabolically active photosynthetic components vs. structural toughness components) contribute to variation in LMA and other leaf economics spectrum traits. Here, we develop a model of plant community dynamics in which species differ in just two traits, photosynthetic and structural LMA components, and we identify optimal values of these traits for early- and late-successional species. Most of the predicted increase in LMA from early- to late-successional species was due to structural LMA. Photosynthetic LMA did not differ consistently between early- and late-successional species, but the photosynthetic LMA to structural LMA ratio declined from early- to late-successional species. Early-successional species had high rates of instantaneous return on leaf mass investment, whereas late-successional species had high lifetime return. Our results provide theoretical support for the primary role of structural (rather than photosynthetic) LMA variation in driving relationships among leaf economics spectrum traits.

The CADILLAC risk score accurately identifies patients at low risk for in-hospital mortality and adverse cardiovascular events following ST elevation myocardial infarction.

BACKGROUND: The CADILLAC risk score was developed to identify patients at low risk for adverse cardiovascular events following ST elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI). METHODS: We performed a single center retrospective review of STEMI hospitalizations treated with PPCI from 2014 to 2018. Patients were stratified using the CADILLAC risk score into low risk, intermediate risk and high risk groups. Patients presenting with cardiac arrest or cardiogenic shock were excluded from the study. The primary outcome was adverse clinical events during initial hospitalization. Secondary outcomes were adverse clinical events at 30 days and 1 year following index hospitalization. RESULTS: The study included 341 patients. Compared to patients with a low CADILLAC score, adverse clinical events were similar in the intermediate risk group during hospitalization (OR 1.23, CI 0.37-4.05, p 0.733) and at 30 days (OR 2.27, CI 0.93-5.56, p 0.0733) while adverse clinical events were significantly elevated in the high risk group during hospitalization (OR 4.75, CI 1.91-11.84, p 0.0008) and at 30 days (OR 8.73, CI 4.02-18.96, p < 0.0001). At 1 year follow-up, compared to the low risk CADILLAC group (9.4% adverse clinical event rate), cumulative adverse clinical events were significantly higher in the intermediate risk group (22.9% event rate, OR 2.86, CI 1.39-5.89, p 0.0044) and in the elevated risk group (58.6% event rate, OR 13.67, CI 6.81-27.43, p < 0.0001). The mortality rate was 0% for patients defined at low risk by CADILLAC score during hospitalization, as well up to 1 year follow up. On receiver operating curve analysis, discrimination of in-hospital adverse clinical events was fair using CADILLAC (C = 0.66, odds ratio 1.18; 95% CI 1.04-1.33; p = 0.0064) with somewhat better discrimination at 30-day follow-up (C = 0.719) and 1-year follow-up (C = 0.715). CONCLUSION: Patients defined as low risk by the CADILLAC score following a STEMI were associated with lower mortality and adverse clinical event rates during hospitalization and up to 1 year following STEMI when compared to those with an intermediate or high CADILLAC score.

Thermo-resistance of ESKAPE-panel pathogens, eradication and growth prevention of an infectious biofilm by photothermal, polydopamine-nanoparticles in vitro.

Nanotechnology offers many novel infection-control strategies that may help prevent and treat antimicrobial-resistant bacterial infections. Here, we synthesized polydopamine, photothermal-nanoparticles (PDA-NPs) without further surface-functionalization to evaluate their potential with respect to biofilm-control. Most ESKAPE-panel pathogens in suspension with photothermal-nanoparticles showed three- to four-log-unit reductions upon Near-Infra-Red (NIR)-irradiation, but for enterococci only less than two-log unit reduction was observed. Exposure of existing Staphylococcus aureus biofilms to photothermal-nanoparticles followed by NIR-irradiation did not significantly kill biofilm-inhabitants. This indicates that the biofilm mode of growth poses a barrier to penetration of photothermal-nanoparticles, yielding dissipation of heat to the biofilm-surrounding rather than in its interior. Staphylococcal biofilm-growth in the presence of photothermal-nanoparticles could be significantly prevented after NIR-irradiation because PDA-NPs were incorporated in the biofilm and heat dissipated inside it. Thus, unmodified photothermal nanoparticles have potential for prophylactic infection-control, but data also constitute a warning for possible development of thermo-resistance in infectious pathogens.

Visualization of Bacterial Colonization and Cellular Layers in a Gut-on-a-Chip System Using Optical Coherence Tomography.

Imaging of cellular layers in a gut-on-a-chip system has been confined to two-dimensional (2D)-imaging through conventional light microscopy and confocal laser scanning microscopy (CLSM) yielding three-dimensional- and 2D-cross-sectional reconstructions. However, CLSM requires staining and is unsuitable for longitudinal visualization. Here, we compare merits of optical coherence tomography (OCT) with those of CLSM and light microscopy for visualization of intestinal epithelial layers during protection by a probiotic Bifidobacterium breve strain and a simultaneous pathogen challenge by an Escherichia coli strain. OCT cross-sectional images yielded film thicknesses that coincided with end-point thicknesses derived from cross-sectional CLSM images. Light microscopy on histological sections of epithelial layers at the end-point yielded smaller layer thicknesses than OCT and CLSM. Protective effects of B. breve adhering to an epithelial layer against an E. coli challenge included the preservation of layer thickness and membrane surface coverage by epithelial cells. OCT does not require staining or sectioning, making OCT suitable for longitudinal visualization of biological films, but as a drawback, OCT does not allow an epithelial layer to be distinguished from bacterial biofilms adhering to it. Thus, OCT is ideal to longitudinally evaluate epithelial layers under probiotic protection and pathogen challenges, but proper image interpretation requires the application of a second method at the end-point to distinguish bacterial and epithelial films.

Artificial Channels in an Infectious Biofilm Created by Magnetic Nanoparticles Enhanced Bacterial Killing by Antibiotics.

The poor penetrability of many biofilms contributes to the recalcitrance of infectious biofilms to antimicrobial treatment. Here, a new application for the use of magnetic nanoparticles in nanomedicine to create artificial channels in infectious biofilms to enhance antimicrobial penetration and bacterial killing is proposed. Staphylococcus aureus biofilms are exposed to magnetic-iron-oxide nanoparticles (MIONPs), while magnetically forcing MIONP movement through the biofilm. Confocal laser scanning microscopy demonstrates artificial channel digging perpendicular to the substratum surface. Artificial channel digging significantly (4-6-fold) enhances biofilm penetration and bacterial killing efficacy by gentamicin in two S. aureus strains with and without the ability to produce extracellular polymeric substances. Herewith, this work provides a simple, new, and easy way to enhance the eradication of infectious biofilms using MIONPs combined with clinically applied antibiotic therapies.

Predicting Survival in Patients Treated With Extracorporeal Membrane Oxygenation After Myocardial Infarction.

OBJECTIVES: Acute myocardial infarction is the most common cause of cardiogenic shock. Although the number of patients with acute myocardial infarction complicated by cardiogenic shock who were treated with venoarterial extracorporeal membrane oxygenation increased during the last decade, detailed data on survival are lacking. We sought to analyze covariates that were independently associated with survival in this patient population and to externally validate the newly developed prEdictioN of Cardiogenic shock OUtcome foR Acute myocardial infarction patients salvaGed by venoarterial Extracorporeal membrane oxygenation (ENCOURAGE) score. DESIGN: Retrospective clinical study. SETTING: A single academic teaching hospital. PATIENTS: Adult patients with acute myocardial infarction complicated by cardiogenic shock who were supported by venoarterial extracorporeal membrane oxygenation from June 2008 to September 2016. INTERVENTIONS: Fourteen individual variables were assessed for their association with the primary endpoint. These variables were prespecified by the study team as being the most likely to affect survival. A receiver operating characteristic analysis was also performed to test the ability of the ENCOURAGE score to predict survival in this patient cohort. MEASUREMENTS AND MAIN RESULTS: The primary endpoint of the study was in-hospital survival. A total of 61 patients were included in the analysis. Thirty-seven (60.7%) could be weaned from venoarterial extracorporeal membrane oxygenation and 36 (59.0%) survived. Survival was significantly higher in patients less than 65 years old (odds ratio, 14.6 [CI, 2.5-84.0]; p = 0.003), whose body mass index was less than 32 kg/m (odds ratio, 5.5 [CI, 1.2-25.4]; p = 0.029) and international normalized ratio was less than 2 (odds ratio, 7.3 [CI, 1.3-40.1]; p = 0.022). In patients where the first lactate drawn was less than 3 mmol/L, the survival was not significantly higher (odds ratio, 4.4 [CI, 0.6-32.6]; p = 0.147). The C-statistic for predicting survival using a modified version of the ENCOURAGE score, which replaced prothrombin activity less than 50% with an international normalized ratio greater than 2, was 0.74 (95% CI, 0.61-0.87). CONCLUSIONS: In this single-center study, several important covariates were associated with improved survival in patients with acute myocardial infarction complicated by cardiogenic shock who were supported by venoarterial extracorporeal membrane oxygenation and the ENCOURAGE score was found to be externally valid for predicting survival to hospital discharge.

Structural changes in S. epidermidis biofilms after transmission between stainless steel surfaces.

Transmission is a main route for bacterial contamination, involving bacterial detachment from a donor and adhesion to receiver surfaces. This work aimed to compare transmission of an extracellular polymeric substance (EPS) producing and a non-EPS producing Staphylococcus epidermidis strain from biofilms on stainless steel. After transmission, donor surfaces remained fully covered with biofilm, indicating transmission through cohesive failure in the biofilm. Counter to the numbers of biofilm bacteria, the donor and receiver biofilm thicknesses did not add up to the pre-transmission donor biofilm thickness, suggesting more compact biofilms after transmission, especially for non-EPS producing staphylococci. Accordingly, staphylococcal density per unit biofilm volume had increased from 0.20 to 0.52 µm-3 for transmission of the non-EPS producing strain under high contact pressure. The EPS producing strain had similar densities before and after transmission (0.17 µm-3). This suggests three phases in biofilm transmission: (1) compression, (2) separation and (3) relaxation of biofilm structure to its pre-transmission density in EPS-rich biofilms.

Visualization of microbiological processes underlying stress relaxation in Pseudomonas aeruginosa biofilms.

Bacterial biofilms relieve themselves from external stresses through internal rearrangement, as mathematically modeled in many studies, but never microscopically visualized for their underlying microbiological processes. The aim of this study was to visualize rearrangement processes occurring in mechanically deformed biofilms using confocal-laser-scanning-microscopy after SYTO9 (green-fluorescent) and calcofluor-white (blue-fluorescent) staining to visualize bacteria and extracellular-polymeric matrix substances, respectively. We apply 20% uniaxial deformation to Pseudomonas aeruginosa biofilms and fix deformed biofilms prior to staining, after allowing different time-periods for relaxation. Two isogenic P. aeruginosa strains with different abilities to produce extracellular polymeric substances (EPS) were used. By confocal-laser-scanning-microscopy all biofilms showed intensity distributions for fluorescence from which rearrangement of EPS and bacteria in deformed biofilms were derived. For the P. aeruginosa strain producing EPS, bacteria could not find new, stable positions within 100 s after deformation, while EPS moved toward deeper layers within 20 s. Bacterial rearrangement was not seen in P. aeruginosa biofilms deficient in production of EPS. Thus, EPS is required to stimulate bacterial rearrangement in mechanically deformed biofilms within the time-scale of our experiments, and the mere presence of water is insufficient to induce bacterial movement, likely due to its looser association with the bacteria.

Compliant Intramedullary Stems for Joint Reconstruction.

The longevity of current joint replacements is limited by aseptic loosening, which is the primary cause of non-infectious failure for hip, knee, and ankle arthroplasty. Aseptic loosening is typically caused either by osteolysis from particulate wear, or by high shear stresses at the bone-implant interface from over-constraint. Our objective was to demonstrate feasibility of a compliant intramedullary stem that eliminates over-constraint without generating particulate wear. The compliant stem is built around a compliant mechanism that permits rotation about a single axis. We first established several models to understand the relationship between mechanism geometry and implant performance under a given angular displacement and compressive load. We then used a neural network to identify a design space of geometries that would support an expected 100-year fatigue life inside the body. We additively manufactured one representative mechanism for each of three anatomic locations, and evaluated these prototypes on a KR-210 robot. The neural network predicts maximum stress and torsional stiffness with 2.69% and 4.08% error respectively, relative to finite element analysis data. We identified feasible design spaces for all three of the anatomic locations. Simulated peak stresses for the three stem prototypes were below the fatigue limit. Benchtop performance of all three prototypes was within design specifications. Our results demonstrate the feasibility of designing patient- and joint-specific compliant stems that address the root causes of aseptic loosening. Guided by these results, we expect the use of compliant intramedullary stems in joint reconstruction technology to increase implant lifetime.

Nano-architectonics of Pt single-atoms and differently-sized nanoparticles supported by manganese-oxide nanosheets and impact on catalytic and anti-biofilm activities.

Hybrid-nanozymes are promising in various applications, but comprehensive comparison of hybrid-nanozymes composed of single-atoms or nanoparticles on the same support has never been made. Here, manganese-oxide nanosheets were loaded with Pt-single-atoms or differently-sized nanoparticles and their oxidase- and-peroxidase activities compared. High-resolution Transmission-Electron-Microscopy and corresponding Fast Fourier Transform imaging showed that Pt-nanoparticles (1.5 nm diameter) had no clear (111) crystal-planes, while larger nanoparticles had clear (111) crystal-planes. X-ray Photo-electron Spectroscopy demonstrated that unloaded nanosheets were composed of MnO2 with a high number of oxygen vacancies (Vo/Mn 0.4). Loading with 7.0 nm Pt-nanoparticles induced a change to Mn2O3, while loading with 1.5 nm nanoparticles increased the number of vacancies (Vo/Mn 1.2). Nanosheets loaded with 3.0 nm Pt-nanoparticles possessed similarly high catalytic activities as Pt-single-atoms. However, loading with 1.5 nm or 7.0 nm Pt-nanoparticles yielded lower catalytic activities. A model is proposed explaining the low catalytic activity of under- and over-sized Pt-nanoparticles as compared with intermediately-sized (3.0 nm) Pt-nanoparticles and single-atoms. Herewith, catalytic activities of hybrid-nanozymes composed of single-atoms and intermediately-sized nanoparticles are put a par, as confirmed here with respect to bacterial biofilm eradication. This conclusion facilitates a balanced choice between using Pt-single-atoms or nanoparticles in further development and application of hybrid-nanozymes.

Understanding Treatment Preferences for Patients with Tricuspid Regurgitation.

Background. Tricuspid regurgitation (TR) is a high-prevalence disease associated with poor quality of life and mortality. This quantitative patient preference study aims to identify TR patients' perspectives on risk-benefit tradeoffs. Methods. A discrete-choice experiment was developed to explore TR treatment risk-benefit tradeoffs. Attributes (levels) tested were treatment (procedure, medical management), reintervention risk (0%, 1%, 5%, 10%), medications over 2 y (none, reduce, same, increase), shortness of breath (none/mild, moderate, severe), and swelling (never, 3× per week, daily). A mixed logit regression model estimated preferences and calculated predicted probabilities. Relative attribute importance was calculated. Subgroup analyses were performed. Results. An online survey was completed by 150 TR patients. Shortness of breath was the most important attribute and accounted for 65.8% of treatment decision making. The average patients' predicted probability of preferring a "procedure-like" profile over a "medical management-like" profile was 99.7%. This decreased to 78.9% for a level change from severe to moderate in shortness of breath in the "medical management-like" profile. Subgroup analysis confirmed that patients older than 64 y had a stronger preference to avoid severe shortness of breath compared with younger patients (P < 0.02), as did severe or worse TR patients relative to moderate. New York Heart Association class I/II patients more strongly preferred to avoid procedural reintervention risk relative to class III/IV patients (P < 0.03). Conclusion. TR patients are willing to accept higher procedural reintervention risk if shortness of breath is alleviated. This risk tolerance is higher for older and more symptomatic patients. These results emphasize the appropriateness of developing TR therapies and the importance of addressing symptom burden. Highlights: This study provides quantitative patient preference data from clinically confirmed tricuspid regurgitation (TR) patients to understand their treatment preferences.Using a targeted literature search and patient, physician, and Food and Drug Administration feedback, a cross-sectional survey with a discrete-choice experiment that focused on 5 of the most important attributes to TR patients was developed and administered online.TR patients are willing to accept higher procedural reintervention risk if shortness of breath is alleviated, and this risk tolerance is higher for older and more symptomatic patients.

Assessment of Volume Status in Hospitalized Patients With Chronic Heart Failure.

Assessment of volume status in hospitalized patients with heart failure is a critically important diagnostic skill that clinicians utilize frequently. However, accurate assessment is challenging and there is often significant inter-provider disagreement. This review serves as an appraisal of current methods of volume assessment amongst different categories of evaluation including patient history, physical exam, laboratory analysis, imaging, and invasive procedures. Within each category, this review highlights methods that are particularly sensitive or specific, or those that carry impactful positive or negative likelihood ratios. Utilization of the information that this review provides will allow clinicians to determine volume status of hospitalized heart failure patients more accurately and more precisely in order to provide appropriate and effective therapies.

Frequency and Predictors of Preoperative Cardiac Testing Overuse in Low-Risk Patients Before Laparoscopic Bariatric Surgery.

Adverse cardiac events after laparoscopic bariatric surgery are rare, yet preoperative cardiology evaluation and testing remain common, resulting in the overuse of cardiac testing in low-risk patients. Our objective was to assess the frequency of, and factors associated with, overuse of preoperative cardiac testing in patients at low cardiac risk before laparoscopic bariatric surgery. We retrospectively reviewed data from 1,094 adult patients who underwent laparoscopic bariatric surgery at our institution from January 1, 2015, through December 31, 2019. The cardiac risk was determined using the Revised Cardiac Risk Index (RCRI) and the National Surgical Quality Improvement Program Myocardial Infarction and Cardiac Arrest (NSQIP MICA) risk model. Multivariate logistic regression was used to evaluate risk factors associated with the overuse of cardiac testing in low-risk patients. Overall, 1,059 patients (96.8%) were estimated to be at low cardiac risk by the RCRI, and 1,094 (100%) were at low cardiac risk by NSQIP MICA. A total of 587 patients (51.8%) were referred to cardiology for preoperative evaluation, and 643 patients (56.7%) underwent one or more preoperative cardiac tests. Factors associated with overuse of preoperative cardiac testing in low-risk patients included preoperative cardiology referral (adjusted odds ratio 37.2, 95% confidence interval 25.3 to 54.7) and patient age (adjusted odds ratio 1.05, 95% confidence interval 1.03 to 1.07). Overuse of preoperative cardiac testing was common in patients at low cardiac risk before laparoscopic bariatric surgery. Preoperative referral to cardiology was the most significant risk factor associated with the overuse of preoperative cardiac testing. Application of risk models such as the RCRI or NSQIP MICA at the time of bariatric program enrollment may reduce unnecessary preoperative cardiac testing in low-risk patients.

Bacterial cell surface damage due to centrifugal compaction.

Centrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we provide a simple, versatile method of analysis for describing the compaction of bacteria during centrifugation based on a proposed centrifugation coefficient, C. Values of C can be related to different bacterial cell surface properties. Changing the geometry of the centrifugation container or centrifugation speeds changed the value of C significantly. Initial deposition rates of Staphylococcus aureus ATCC 12600 to a glass surface decayed exponentially from 4,217 to 1,478 cm⁻² s⁻¹ with increasing C, while the proportion of staphylococci with a zeta potential of around -15 mV decreased from 97 to 58%. These surface-sensitive parameters were used independently to derive a critical centrifugation coefficient (0.040), above which centrifugation was considered to impact the outcome of surface-sensitive experiments due to cell surface damage. The critical centrifugation coefficient could successfully predict staphylococcal cell surface damage, i.e., a significant change in initial deposition rate or zeta potential distribution, in 84% of all cases included here, whereas the centrifugation speed could predict damage in only 58% of all cases. Moreover, controlling the centrifugation coefficient within narrow limits over a series of experiments yielded 43% smaller standard deviations in initial staphylococcal deposition rates than with centrifugation at fixed speeds for replicate experiments.