In situthermal noise measurements under nanoindentation of suspended graphene.

We demonstrated thermal noise measurement under the nanoindentation of monolayer and bilayer graphene nanodrums. The resonant oscillation of the cantilever excited only by a thermal energy is detectable even in the case of contact with a suspended graphene. The contact resonance fRequency can be obtained in 1 millisecond intervals during the force curve measurement by optimizing the parameters of a real-time spectrum analyzer. The pretension value of the graphene nanodrum is evaluated by the minimum frequency just when the applied force of the cantilever becomes zero. The simultaneous measurement of the force and the resonant frequency with respect to the deformation of the graphene nanodrum enables us to determine the value of InvOLS (inverse optical lever sensitivity) more accurately in each measurement. From the analysis scheme, force curve measurements of the graphene nanodrums with the same diameters show good reproducibility. We also revealed that the effective spring constant of the graphene nanodrums consists of a weak sample-dependent pretension factor and a deformation-dependent factor proportional to the number of graphene layers.

Comparison of symptomatic unstable ankle with and without os subfibulare.

BACKGROUND: This study aimed to compare the patients background, clinical scores, condition of the lateral ligament, mechanical instabilities, and chondral lesions in ankles with symptomatic os subfibulare compared to those in ankles with chronic lateral instability without os subfibulare. METHODS: Of the 212 ankles with a chronic lateral instability that were surgically treated, 72 ankles had an os subfibulare. All ankles were examined by arthroscopy during surgery. Age, sex, preoperative American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale scores, remnant condition of the lateral ligaments, and chondral lesions were compared between ankles with symptomatic os subfibulare and ankles with chronic lateral instability without os subfibulare. RESULTS: There were no statistically significant differences between the groups in terms of the sex ratio (males: females, 35:37 vs. 53:87, n.s.) and the AOFAS Ankle-Hindfoot Scale scores (median; 75 vs. 77, n.s.). There were statistically significant differences in patient age (median: 20 vs. 24.5 years, p < 0.01), talar tilt angle (median: 9.0° vs 12.0°, p < 0.01), anterior drawer distance (6.2 vs. 7.0 mm, p < 0.01), chondral lesions (G0:G1:G2:G3, 35:21:66:5 vs. 40:44:27:29, p < 0.01), condition of the anterior talofibular ligament (intact: repairable remnant: poor remnant, 0:70:2 vs. 1:112:27, p < 0.01), and condition of the calcaneofibular ligament (intact: repairable remnant: poor remnant, 44:26:2 vs. 77:35:28, p < 0.01) between the groups. CONCLUSION: This study suggests that the condition of the lateral ligaments including mechanical instability and cartilage of the ankle were less severe in the ankles with symptomatic os subfibulare than in those with chronic lateral instability without os subfibulare. The patients' age was lower in the ankles with symptomatic os subfibulare than in those with chronic lateral instability without os subfibulare. The clinical scores and gender ratio were not statistically different between the group.

[A Case of Laparoscopic Gastrectomy for Gastric Cancer Occurring after Coronary Artery Bypass Grafting Using the Right Gastroepiploic Artery].

We present a case of 72-year-old man who was diagnosed with gastric cancer that occurred after coronary artery bypass grafting(CABG)with the right gastroepiploic artery(RGEA). Gastrointestinal endoscopy revealed a 0-Ⅱc lesion at the posterior wall of gastric angle, and diagnosis was cStage Ⅰ(T2N0M0). Cardiac computed-tomography showed an occlusion of the RGEA graft, suggesting that the RGEA graft could be ligated and dissected. Coronary angiography showed no severe stenosis of the right coronary artery, suggesting that coronary revascularization was not necessary. He underwent laparoscopic distal gastrectomy with D2 lymph node dissection. During the operation, the RGEA graft was dissected after clamp test for 20 minutes to confirm no cardiac event. In such cases, it is crucial to consider whether it is possible or not to dissect the RGEA graft and whether to restore the coronary flow with preoperative meticulous examination.

Effect of Ankle Motion and Tensile Stress at the Achilles Tendon on the Contact Pressure Between the Achilles Tendon and the Calcaneus.

Impingement between the Achilles tendon and the posterosuperior prominence of the calcaneus is considered to be a cause of insertional Achilles tendinopathy. The corresponding treatment intends to reduce tensile stress from calf muscles and avoid hyper-dorsiflexion of the ankle joint for decreasing the contact pressure; however, no study has reported on whether these treatments can decrease impingement. Thus, this study investigated the hypothesis that the tensile stress of the Achilles tendon and ankle motion affect the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus. Six fresh-frozen cadaveric lower leg specimens were procured. Each specimen was set to a custom foot-loading frame and loaded with a ground reaction force of 40 N and a tensile load of 70 N along the Achilles tendon. The contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus was measured using a miniature pressure sensor under different tensile loadings of the Achilles tendon at the neutral ankle position. Similarly, the contact pressures during the ankle motion from a neutral position to maximum dorsiflexion were measured. The tensile load of the Achilles tendon and ankle motion affected the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus. The contact pressure increased with tensile load or ankle dorsiflexion. Conditions with increasing the tensile load of the Achilles tendon or under ankle dorsiflexion increase the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus.

[Preoperative Esophageal Decompression and Enteral Nutrition Using a W-ED Tube in Patients with Esophagogastric Junction Cancer-A Case Report].

The patient was a 67-year-old male diagnosed with adenocarcinoma of the esophagogastric junction. The esophagus was markedly dilated due to severe stenosis, and aspiration pneumonia was observed. Therefore, he was treated with a W- ED tube for simultaneous esophageal decompression and enteral nutrition. Two weeks of W-ED tube placement improved esophageal dilatation and pneumonia while maintaining nutritional status; thus, he underwent proximal gastrectomy, lower esophagectomy and combined resection of distal pancreas, spleen and left crus of diaphragm with jejunal interposition reconstruction. His postoperative course was uneventful, and he was discharged 16 days after surgery without any postoperative infectious complications such as pneumonia, anastomotic leakage, pancreatic fistula and enterocolitis. In the preoperative management for patients with esophagogastric junction cancer with severe stenosis, simultaneous esophageal decompression and enteral nutrition using a W-ED tube is very useful because it can improve aspiration pneumonia, reduce the risk of anastomotic leakage by improving esophageal edema, and prevent disuse atrophy of small intestinal villi.

[A Case of Gastric Carcinoma with Lymphoid Stroma That Was Difficult to Diagnose Preoperatively].

A 71-year-old man was referred to our hospital because of a gastric submucosal tumor. Gastrointestinal stromal tumor (GIST)was diagnosed in the antrum of the stomach and local resection was undergone. At this time, upper gastrointestinal endoscopy found the gastric submucosal tumor with a size of about 5 mm on the posterior wall of the fundus, but it was followed up. The lesion had grown to a size of about 10 mm by endoscopy 2 years later, and a biopsy was performed. Gastric mucosa associated lymphoid tissue(MALT)lymphoma was diagnosed by pathological examination, and Helicobacter pylori eradication therapy was performed. Endoscopy after treatment further increased the size of the lesion to about 20 mm, and ulceration was also observed. A biopsy was performed again, and a diagnosis of poorly differentiated adenocarcinoma was made, and laparoscopic proximal gastrectomy was undergone. It was the diagnosis of gastric carcinoma with lymphoid stroma(GCLS), pT3N0M0, pStage ⅡA in the postoperative pathological examination. GCLS is a rare disease with a frequency of about 1 to 4% of all gastric cancers, and preoperative diagnosis is difficult. From the morphology and histology, the differential diagnosis from submucosal tumors and lymphomas becomes problems.

[A Case of Gastric Cancer with Extensive Lymph Node Metastasis Causing Stenosis Symptoms in the Primary pCR after Preoperative Chemotherapy].

A 65‒year‒old man was found with a circumferential type 2 tumor in the gastric antrum by upper gastrointestinal endoscopy, and biopsy revealed poorly a differentiated adenocarcinoma and HER2‒negative results. According to imaging examinations and laparoscopy, he was diagnosed with an advanced gastric cancer, classified as cT4a(SE)N3M0 and cStage Ⅲ. He underwent neoadjuvant chemotherapy(SOX regimen)because of the bulky N finding. After 2 courses of the treatment, marked reductions in the primary gastric lesion and metastatic lymph nodes were observed, although stenosis appeared at the gastric tumor site. The W‒ED tube was used to depressurize the stomach and to manage his nutrition, and the patient's surgery was conducted under good general conditions. We performed a distal gastrectomy(D2 dissection)and cholecystectomy. Histopathological examination showed no viable tumor cells in the primary gastric lesion(Grade 3). Two metastases were found in the dissected lymph nodes, although only a few cancer cells persisted. We report a case of gastric cancer in which pCR was obtained in the primary lesion, although stenosis appeared after the neoadjuvant chemotherapy.

[A Surgical Case Report of Gastric Cancer Patient with Severe COPD Successfully Controlled by Preoperative Pulmonary Rehabilitation].

A 72-year-old man with a history of chronic obstructive pulmonary disease(COPD)was diagnosed with type 3 gastric cancer at the posterior wall of the gastric body. Although there was no distant metastasis in preoperative imaging tests, pulmonary function test revealed severe obstructive ventilatory impairment, suggesting that the patient had high risks of perioperative pulmonary complications. After treatment for COPD and preoperative pulmonary rehabilitation under hospitalization for 2 weeks, laparoscopic distal gastrectomy plus D2 lymphadenectomy plus Roux-en-Y reconstruction was performed. The patient showed stable respiratory condition postoperatively, and was discharged from hospital on postoperative day 12 without serious postoperative complications. It was suggested that preoperative pulmonary rehabilitation reduced postoperative pulmonary complications and allowed safe surgery in patients with severe COPD.

Bartonella henselae DNA in Seronegative Patients with Cat-Scratch Disease.

We used real-time PCR to detect Bartonella henselae DNA in 7.9% (5/63) of blood specimens from seronegative patients in Japan suspected of having cat-scratch disease. The combined use of serologic tests and real-time PCR to analyze blood specimens is recommended for the prompt, noninvasive laboratory diagnosis of cat-scratch disease.

Recurrent Dislocation of the Tibialis Posterior Tendon Treated With Suture Tape: A Case Report of an Innovative Operative Procedure.

Dislocation of the tibialis posterior tendon (PTT) is a rare traumatic injury, and treatment is often delayed. Conservative treatment is ineffective for recurrent dislocation of the PTT; however, a reference standard procedure has not yet been established. In the present case report, we describe an innovative pseudo-pouch closing procedure with suture tape and a suture anchor for recurrent PTT dislocation. The patient returned to preoperative levels of activity at 21 weeks postoperatively and was asymptomatic at the 1-year follow-up examination.

Hypothermia Reduces but Hyperthermia Augments T Cell-Derived Release of Interleukin-17 and Granzyme B that Mediate Neuronal Cell Death.

BACKGROUND: T cells infiltrate into the infarcted brain within days after cerebral ischemia and play essential roles in exacerbating the delayed phase of the brain injury by producing pro-inflammatory factors. However, the involvement of these factors in brain damage is also demonstrated systemically. Such periphery-brain abnormalities are interesting because they may constitute a pathway to the central nervous system (CNS), which may be a target of therapeutic hypothermia. Although this therapy protects neurons after severe brain damage, the underlying mechanisms are partly understood. We examined the effects of hypothermic and hyperthermic cultures on peripheral T cell-derived release of interleukin (IL)-17 and granzyme B (GrB) and evaluated whether and how these factors induced neurotoxicity and activated brain endothelial cells. METHODS: We determined levels of IL-17 and GrB produced by several activated, IL-1ß/IL-23-treated activated T cells (naïve CD4(+), CD4(+), CD8(+), and γδ T cells obtained from healthy humans) under hypothermia, normothermia, and hyperthermia. The viability of neuronal SH-SY5Y cells treated with IL-17 or GrB and mRNA expression of adhesion molecules/chemokines by brain endothelial bEND.3 cells treated with IL-17 were also measured. RESULTS: Compared with normothermia, IL-17 and GrB release in these T cells was reduced by hypothermia but augmented by hyperthermia. IL-17 and GrB caused the death of neuronal SH-SY5Y cells, and IL-17 upregulated mRNA expression of several adhesion molecules/chemokines in bEND.3 cells; both effects were concentration-dependent. CONCLUSION: Hypothermia reduced but hyperthermia augmented T cell-derived release of IL-17 and GrB that mediate neuronal cell death, suggesting that the attenuation of T cell-derived release of these factors by therapeutic hypothermia leads to the inhibition of neuronal cell death in the delayed phase of brain injury. Moreover, hypothermia may suppress but hyperthermia may promote the recruitment of inflammatory cells to CNS by regulating brain endothelial activation of IL-17.

Hypothermia at 35 °C reduces the time-dependent microglial production of pro-inflammatory and anti-inflammatory factors that mediate neuronal cell death.

BACKGROUND: Therapeutic hypothermia protects neurons after severe brain damage. This effect has been mainly achieved at the core temperatures of 32-34 °C; however, the optimum temperature of therapeutic hypothermia is not fully defined. Here we studied whether hypothermic culture at 35 °C had the same effects on the decrease of time-dependent expression of tumor necrosis factor (TNF)-α, interleukin (IL)-10, and nitric oxide (NO) by stimuli-activated microglia as that at 33 °C, as determined in our previous reports, and whether these factors directly induced neuronal cell death. METHODS: We determined the levels of cytokines and NO produced by microglia cultured with adenosine triphosphate (ATP), a toll-like receptor (TLR)2 agonist (N-palmitoyl-S-(2,3-bis(palmitoyloxy)-(2R,S)-propyl)-(R)-cysteinyl-seryl-(lysyl)3-lysine, Pam(3)CSK(4)), or a TLR4 agonist (lipopolysaccharide) under mild hypothermic (33 °C), minimal hypothermic (35 °C), and normothermic (37 °C) conditions. We also determined the viability of rat neuronal pheochromocytoma PC12 cells treated with recombinant TNF-α or IL-10 or (±)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR3, an NO donor). RESULTS: Production of TNF-α, as well as that of IL-10 and NO were decreased by minimal hypothermia at 1.5-6, and 24-48 h, respectively, compared with normothermia, although some effects were diminished as compared with those by mild hypothermia. Exposure to TNF-α, IL-10, and NOR3 caused the death of PC12 cells in a concentration-dependent manner after 24 h. CONCLUSION: Hypothermic culture at 35 °C decreased the production of early-phase TNF-α and late-phase IL-10 and NO from ATP- and TLR-activated microglia as observed at 33 °C, albeit with diminished effects. Moreover, these factors caused the death of neuronal cells in a concentration-dependent manner. These results suggest that the attenuation of microglial production of TNF-α, IL-10, and NO by therapeutic hypothermia leads to the inhibition of neuronal cell death. Minimal hypothermia at 35 °C may be sufficient to elicit neuroprotective effect.

Arthroscopic debridement and microfracture for bilateral osteochondral lesions on the lateral process of the talus involving the subtalar joint: A case report.

RATIONALE: Osteochondral lesions on the lateral process of the talus involving the subtalar joint are rare; the optimal surgical treatment remains to be clarified as there are few reports. Additionally, bilateral cases are extremely rare. Therefore, the clinical outcomes of the surgical treatment for bilateral osteochondral lesions on the lateral process of the talus involving the subtalar joint have not been fully elucidated. PATIENT CONCERNS: A 16-year-old boy who played soccer presented to our hospital with bilateral hindfoot pain. The symptoms persisted even after 3 months of conservative treatment. The patient and family requested surgical treatment to relieve the symptoms. DIAGNOSES: The patient was diagnosed with bilateral osteochondral lesions on the lateral process of the talus, involving the subtalar joint based on computed tomography and magnetic resonance imaging findings. INTERVENTIONS: Arthroscopic debridement and microfracture were performed bilaterally. OUTCOMES: Postoperative computed tomography and magnetic resonance imaging of both feet revealed remodeling of the subchondral bone. The patient returned to play at the pre-injury level with no pain. LESSONS: This report describes a case of bilateral osteochondral lesions on the lateral process of the talus, involving the subtalar joint. Arthroscopic debridement and microfracture were effective in relieving symptoms and the subchondral bone remodeling. To the best of our knowledge, this is the first report of arthroscopic treatment of osteochondral lesions of the lateral process of the talus involving the subtalar joint.

Anterior Ankle Impingement Syndrome With Spur Fragmentation: Is It an Os Talotibiale?

Background: Bone fragments are often found in ankles with anterior bony impingement. However, whether they are detached osteophytes or accessory bones remains unknown. Methods: Among the 66 continuously enrolled cases of ankles with anterior bony impingement, 32 had a fragment located at the anterior margin of the tibia. The cases of posterior impingement, lateral instability, osteochondral lesions, or free bodies simultaneously treated were excluded. The enrolled subjects were classified into 2 groups: ankles without (group A) and with remarkable spurs (group B). The patients' backgrounds, location of the fragments, clinical scores, and other parameters required to resume sports were compared. The Japanese Society for Surgery of the Foot (JSSF) ankle rating scale was used to evaluate preoperative and postoperative ankle conditions, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) was used to evaluate postoperative sports abilities. Results: Eight (seven subjects) and 11 ankles were classified into groups A and B, respectively, and the mean age of the 18 patients was 25.4 (range, 16-37) years. No statistical differences in patient backgrounds or fragment sizes between the groups existed. In group A, the fragments were located on the lateral plateau in 7 of the 8 ankles, whereas in group B, their locations varied. The patients were followed up for a median of 48 months (range, 24-168). No complications were observed. The postoperative JSSF and SAFE-Q sports activity scores were significantly higher in group A than in group B (P <.01 and <.001, respectively). The postoperative term to return to their original sports activities was significantly shorter in group A (P < .05). Conclusion: Anterior bony fragments of the ankle without a remarkable spur were located at a specific site, and the results of arthroscopic treatment were better than in those with remarkable spurs. Such a fragment may be called an os talotibiale. Level of Evidence: Level III, retrospective cohort study.

Hypothermia reduces toll-like receptor 3-activated microglial interferon-ß and nitric oxide production.

Therapeutic hypothermia protects neurons after injury to the central nervous system (CNS). Microglia express toll-like receptors (TLRs) that play significant roles in the pathogenesis of sterile CNS injury. To elucidate the possible mechanisms involved in the neuroprotective effect of therapeutic hypothermia, we examined the effects of hypothermic culture on TLR3-activated microglial release of interferon (IFN)- ß and nitric oxide (NO), which are known to be associated with neuronal cell death. When rat or mouse microglia were cultured under conditions of hypothermia (33°C) and normothermia (37°C) with a TLR3 agonist, polyinosinic-polycytidylic acid, the production of IFN- ß and NO in TLR3-activated microglia at 48 h was decreased by hypothermia compared with that by normothermia. In addition, exposure to recombinant IFN- ß and sodium nitroprusside, an NO donor, caused death of rat neuronal pheochromocytoma PC12 cells in a concentration-dependent manner after 24 h. Taken together, these results suggest that the attenuation of microglial production of IFN- ß and NO by therapeutic hypothermia leads to the inhibition of neuronal cell death.

Change of signal intensity in the displaced medial meniscus after its reduction on MRI.

PURPOSE: To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury. METHODS: Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1-2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients. RESULTS: In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients. CONCLUSIONS: A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Relationship between the morphology of osteophytes and cartilage lesions in anterior ankle impingement in athletes: a cross-sectional study.

BACKGROUND: The present study aimed to describe the frequency and severity of tram-track lesions in anterior ankle impingement in athletes and to evaluate the association between osteophyte morphology and severity of tram-track lesions, the distinctive cartilage lesions associated with tibial osteophytes in anterior ankle impingement syndrome. METHODS: We evaluated 34 athletes who underwent arthroscopic osteophyte resection for anterior ankle impingement between January 2017 and March 2021. RESULTS: We found tram-track lesions in 26 athletes (76.5%). Arthroscopic findings revealed the distribution of the International Cartilage Repair Society grades of tram-track lesions (grade 0, eight; grade 1, seven; grade 2, ten; grade 3, nine; grade 4, zero). These findings indicate that athletes with anterior ankle impingement syndrome may have more severe cartilage lesions than non-athletes. There was a positive correlation between the International Cartilage Repair Society grade and osteophyte size (r = 0.393, p = 0.021). We divided athletes into two groups according to the presence or absence of osteophyte protrusion into the joint space. Osteophyte protrusion was present in 14 athletes (41.2%). All athletes in the protrusion-type group had tram-track lesions; seven (50%) had International Cartilage Repair Society grade 3. The protrusion-type group's International Cartilage Repair Society grade was significantly higher than that of the non-protrusion-type group (p = 0.008). The osteophyte sizes in the two groups were not significantly different (p = 0.341). CONCLUSIONS: Based on these findings, osteophyte protrusion should be assessed when an indication of arthroscopic treatment for anterior ankle impingement syndrome is considered, particularly in athletes.

Temperature-related effects of adenosine triphosphate-activated microglia on pro-inflammatory factors.

BACKGROUND: Therapeutic hypothermia protects neurons after severe brain injury. Activated microglia produce several neurotoxic factors, such as pro-inflammatory cytokines and nitric oxide (NO), during neuron destruction. Hence, suppression of microglial release of these factors is thought to contribute partly to the neuroprotective effects of hypothermia. After brain insults, adenosine triphosphate (ATP) is released from injured cells and activates microglia. Here, we examined the acute effects of temperature on ATP-activated microglial production of inflammatory factors, and the possible involvement of p38 mitogen-activated protein kinase (p38) underlying such effects. METHODS: Microglia were cultured with ATP at 33, 37, and 39°C, or with ATP in the presence of a p38 inhibitor, SB203580, at 37°C. Cytokine and NO levels, and p38 activation were measured. RESULTS: Compared to 37°C, TNF-α was reduced at 33°C and augmented at 39°C for 1.5 h. IL-6 was reduced at 33°C for 6 h. NO was reduced at 33°C, but augmented at 39°C for 6 h. p38 was reduced at 33°C for 1 min. SB203580 inhibited ATP-induced TNF-α, IL-6, and NO production. CONCLUSION: Lowering temperature rapidly reduced p38 activation and the subsequent p38-regulated production of pro-inflammatory cytokines and NO in ATP-activated microglia, suggesting that attenuation of early phase inflammatory responses via suppression of p38 in microglia is one possible neuroprotective mechanism of therapeutic hypothermia. Temperature elevation increased TNF-α and NO production in these cells. These temperature-dependent changes imply that monitoring of TNF-α and NO in the cerebrospinal fluid during the early phase might be useful as biomarkers for responses to therapeutic hypothermia and hyperthermia.

Two-Dimensional Superconductivity of Ca-Intercalated Graphene on SiC: Vital Role of the Interface between Monolayer Graphene and the Substrate.

Ca-intercalation has enabled superconductivity in graphene on SiC. However, the atomic and electronic structures that are critical for superconductivity are still under discussion. We find an essential role of the interface between monolayer graphene and the SiC substrate for superconductivity. In the Ca-intercalation process, at the interface a carbon layer terminating SiC changes to graphene by Ca-termination of SiC (monolayer graphene becomes a bilayer), inducing more electrons than a free-standing model. Then, Ca is intercalated in between the graphene layers, which shows superconductivity with the updated critical temperature (TC) of up to 5.7 K. In addition, the relation between TC and the normal-state conductivity is unusual, "dome-shaped". These findings are beyond the simple C6CaC6 model in which s-wave BCS superconductivity is theoretically predicted. This work proposes a general picture of the intercalation-induced superconductivity in graphene on SiC and indicates the potential for superconductivity induced by other intercalants.

Arthroscopic Treatment of Posterior Ankle Impingement Syndrome: Mid-Term Clinical Results and a Learning Curve.

PURPOSE: To report mid-term clinical results of posterior ankle arthroscopy in the treatment of posterior ankle impingement syndrome (PAIS) and to assess the learning curve and its influence on the results. METHODS: This was a retrospective evaluation of the clinical outcomes of posterior ankle arthroscopy and its learning curve in a series of patients with PAIS. Demographic and clinical data, surgical time, the American Orthopaedic Foot Ankle Society (AOFAS) ankle/hindfoot scores, and time to resumption of sports were recorded. RESULTS: Fifty-nine patients with 72 posterior ankle arthroscopies were evaluated at a mean follow-up period of 60 months (24-133 months). Causes of PAIS were an os trigonum (50), a large posterior talar process (14), and soft-tissue impingement (8). There were 29 male and 30 female patients. The average age was 21.8 years (12-74 years). The average preoperative AOFAS score improved significantly from 79.6 to 97.6 postoperatively (P < .0001). The average time taken to resume training was 5.3 weeks, and the time to return to a competitive condition was 13.4 weeks. The times to resumption of training were shorter in elite athletes than local competitive athletes. The learning curve of the posterior ankle arthroscopy was detected and determined by a logarithmic trendline and moving averages. An experience of 26 cases was required to be proficient in posterior arthroscopies. The postoperative AOFAS scores were not statistically different between the initial and the latest 10 series each. CONCLUSIONS: The mid-term follow-up results of endoscopic treatment for the PAIS were good, with a high success rate in returning to sports activities. Although a learning curve effect was detected in our series of arthroscopic treatment for the PAIS due to os trigonum, a low volume of experience did not affect the results. LEVEL OF EVIDENCE: Level IV, therapeutic case series.