Revealing CO2 dissociation pathways at vicinal copper (997) interfaces.

Size- and shape-tailored copper (Cu) nanocrystals can offer vicinal planes for facile carbon dioxide (CO2) activation. Despite extensive reactivity benchmarks, a correlation between CO2 conversion and morphology structure has not yet been established at vicinal Cu interfaces. Herein, ambient pressure scanning tunneling microscopy reveals step-broken Cu nanocluster evolutions on the Cu(997) surface under 1 mbar CO2(g). The CO2 dissociation reaction produces carbon monoxide (CO) adsorbate and atomic oxygen (O) at Cu step-edges, inducing complicated restructuring of the Cu atoms to compensate for increased surface chemical potential energy at ambient pressure. The CO molecules bound at under-coordinated Cu atoms contribute to the reversible Cu clustering with the pressure gap effect, whereas the dissociated oxygen leads to irreversible Cu faceting geometries. Synchrotron-based ambient pressure X-ray photoelectron spectroscopy identifies the chemical binding energy changes in CO-Cu complexes, which proves the characterized real-space evidence for the step-broken Cu nanoclusters under CO(g) environments. Our in situ surface observations provide a more realistic insight into Cu nanocatalyst designs for efficient CO2 conversion to renewable energy sources during C1 chemical reactions.

Effect of Quality of Repair on Clinical and Structural Outcomes of Rotator Cuff Repair.

BACKGROUND: Anatomic repair of a torn rotator cuff tendon on the greater tuberosity (GT) is an important surgical goal in rotator cuff repair. However, few studies have investigated whether the efforts made to maximize coverage of the GT are associated with the clinical and structural outcomes after rotator cuff repair surgery. PURPOSE: To investigate whether the quality of repair at the time of surgery is associated with clinical and structural outcomes after surgery and to identify factors influencing the quality of repair. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were retrospectively collected from 141 patients who underwent arthroscopic rotator cuff repair between 2008 and 2016. All repairs were classified according to the amount of postoperative GT coverage: A, complete coverage of the GT (n = 96); B, incomplete coverage, comprising more than half of GT (n = 27); C, incomplete coverage, comprising less than half of the GT (n = 16); and D, exposure of the glenohumeral joint (n = 2). All patients underwent magnetic resonance imaging 1 year after surgery. Clinical outcomes and structural integrity based on Sugaya classification were assessed 2 years and 1 year after surgery, respectively. Preoperative factors associated with the postoperative GT coverage (measured at the close of surgery) were identified using a multivariable proportional odds cumulative logit model. RESULTS: The forward flexion strength in group A (10.3 ± 4.6 lb) was significantly greater than that in group C (6.5 ± 3.7 lb) (P = .003) 2 years after surgery. The postoperative Constant score in group A (76.6 ± 11.5) was greater than that in group C (66.7 ± 15.6) (P = .018). The number of cases that showed retearing of the repaired tendon was as follows: group A (5/96; 5.2%), group B (7/27; 25.9%), and group C (10/16; 62.5%). There was no significant difference in the changes of pain visual analog scale scores among groups 2 years after surgery (all P > .05). Also, there was no significant difference in the changes of range of motion in all directions among groups 2 years after surgery (all P > .05). Patients with preoperative GT coverage B included in the postoperative GT coverage groups through surgery were as follows: group A (23/45; 51.1%), group B (17/45; 37.8%), and group C (5/45; 11.1%). Preoperative GT coverage was the only independent factor that was associated with GT coverage in multivariable analysis. CONCLUSION: Quality of repair, measured as the extent of postoperative GT coverage at the time of surgery, was associated with clinical and structural outcomes after rotator cuff repair surgery.

Direct Observation of Atomic-Scale Gliding on Hydrophilic Surfaces.

Nanoscale friction behavior on hydrophilic surfaces (HS), influenced by a probe gliding on a confined water layer, has been investigated with friction force microscopy under various relative humidity (RH) conditions. The topographical and frictional responses of the mechanically exfoliated single-layer graphene (SLG) on native-oxide-covered silicon (SiO2/Si) and mica were both influenced by RH conditions. The ordinary phenomena at ambient conditions (i.e., higher friction on a HS than on a SLG due to different hydrophilicity), nondistinguishable height, friction of SLG with SiO2/Si at high RH (>98%), and the superlubricating behavior of friction on a HS were observed. Furthermore, the subdomain within SLG, consisting of an ice-like water layer intercalated between SLG and SiO2/Si, showed friction enhancement. These results suggest that the abundant water molecules at the interface of the probe and a HS can make a slippery surface that overcomes capillary and viscosity effects through the gliding motion of the probe.

Prevalence of Accessory Bones and Tarsal Coalitions Based on Radiographic Findings in a Healthy, Asymptomatic Population.

BACKGROUND: Accessory bones and tarsal coalitions are the most common developmental variations of the foot and ankle. However, their clinical implications are not well understood because there is no established prevalence data in the normal population and the reported prevalence varies widely. Therefore, we aimed to investigate the incidence of accessory ossicles and tarsal coalitions in a healthy, asymptomatic Korean population. METHODS: A total of 448 healthy, asymptomatic participants (224 men and 224 women; 896 feet) were enrolled and stratified by age and sex. To investigate the presence of accessory bones and tarsal coalitions in the foot and ankle, we obtained the weight-bearing standing radiographs (anteroposterior and lateral views) from each participant. RESULTS: Accessory ossicles were found in 49.2% of the healthy, asymptomatic Korean adults. The prevalence of accessory bones in adults was the highest with 34% for the accessory navicular, 5.8% for the os trigonum, 3.9% for the os peroneum, and 1.7% for the os subfibulare. The prevalence of tarsal coalitions in adults was 0.4% and that of symphalangism was 16% for the fourth toe and 80.6% for the fifth toe. The frequency of the accessory navicular and fifth toe symphalangism was significantly higher in women. Most of the accessory navicular and fourth and fifth toe symphalangism were bilateral, whereas the os subfibulare was mostly unilateral. CONCLUSIONS: The prevalence of accessory bones and tarsal coalitions in the healthy, asymptomatic Korean population showed some variation according to age and sex.

Reduction and fixation of anterior inferior tibiofibular ligament avulsion fracture without syndesmotic screw fixation in rotational ankle fracture.

OBJECTIVE: We aimed to present the radiographic and functional outcomes of anatomical reduction and fixation of anterior inferior tibiofibular ligament (AITFL) avulsion fracture without syndesmotic screw fixation in rotational ankle fracture. METHODS: We retrospectively reviewed 66 consecutive patients with displaced malleolar fracture combined with AITFL avulsion fracture. We performed reduction and fixation for the AITFL avulsion fracture when syndesmotic instability was present after malleolar fracture fixation. A syndesmotic screw was inserted only when residual syndesmotic instability was present even after AITFL avulsion fracture fixation. The radiographic parameters were compared with those of the contralateral uninjured ankles. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores were assessed 1 year postoperatively. RESULTS: Fifty-four patients showed syndesmotic instability after malleolar fracture fixation and underwent reduction and fixation for AITFL avulsion fracture. Among them, 45 (83.3%) patients achieved syndesmotic stability, while 9 (16.7%) patients with residual syndesmotic instability needed additional syndesmotic screw fixation. The postoperative radiographic parameters were not significantly different from those of the uninjured ankles. The mean AOFAS score was 94. CONCLUSION: Reduction and fixation of AITFL avulsion fracture obviated the need for syndesmotic screw fixation in more than 80% of patients with AITFL avulsion fracture and syndesmotic instability.