On Torus Knots obtained by Self-Fusions on the Torus

For the torus knot on the standard torus in S3, we can get another torus knot by performing a self-fusion on the torus. In the present paper, we detect the relationship between those two torus knots, and show a necessary and sufficient condition for the torus knot to become the trivial knot by once self-fusion. Moreover for a given positive integer p > 0, we show a necessary and sufficient condition for T(p, q) to become the trivial knot by maximal times of self-fusions

Alveolar soft part sarcoma: progress toward improvement in survival? A population-based study

Background Alveolar soft part sarcoma (ASPS) is a rare histological subtype of soft-tissue sarcoma, which remains refractory to conventional cytotoxic chemotherapy. We aimed to characterize ASPS and investigate whether the oncological outcome has improved over the past decade. Methods One hundred and twenty patients with newly diagnosed ASPS from 2006 to 2017, identified from the Bone and Soft-Tissue Tumor Registry in Japan, were analyzed retrospectively. Results The study cohort comprised 34 (28%) patients with localized ASPS and 86 (72%) with metastatic disease at presentation. The 5-year disease-specific survival (DSS) was 68% for all patients and 86% and 62% for localized and metastatic disease, respectively (p = 0.019). Metastasis at presentation was the only adverse prognostic factor for DSS (hazard ratio [HR]: 7.65; p = 0.048). Patients who were > 25 years (80%; p = 0.023), had deep-seated tumors (75%; p = 0.002), and tumors > 5 cm (5-10 cm, 81%; > 10 cm, 81%; p < 0.001) were more likely to have metastases at presentation. In patients with localized ASPS, adjuvant chemotherapy or radiotherapy did not affect survival, and 13 patients (45%) developed distant metastases in the lung (n = 12, 92%) and brain (n = 2, 15%). In patients with metastatic ASPS (lung, n = 85 [99%]; bone, n = 12 [14%]; and brain n = 9 [11%]), surgery for the primary or metastatic site did not affect survival. Prolonged survival was seen in patients who received pazopanib treatment (p = 0.045), but not in those who received doxorubicin-based cytotoxic chemotherapy. Overall, improved DSS for metastatic ASPS has been observed since 2012 (5-year DSS, from 58 to 65%) when pazopanib was approved for advanced diseases, although without a statistically significant difference (p = 0.117). Conclusion The national study confirmed a unique feature of ASPS with frequent metastasis to the lung and brain but an indolent clinical course. An overall trend toward prolonged survival after the introduction of targeted therapy encourages continuous efforts to develop novel therapeutic options for this therapeutically resistant soft-tissue sarcoma

Perineal Squamous Cell Carcinoma Arising in an Epidermal Cyst

A 90-year-old Japanese woman who had been aware of a subcutaneous mass on the right perineal region for 5 years was referred to our hospital for further examination and treatment because of the rapid growth of the mass and bleeding that began 3 months earlier. A biopsy of the mass revealed a diagnosis of well-differentiated squamous cell carcinoma. On preoperative examination, the tumor was 90×40 mm in size and was suspected to have partially invaded the levator ani muscle and external sphincter. Since a preoperative cardiac evaluation indicated severe aortic stenosis, we performed transcatheter aortic valve implantation. A radical resection was then performed with general anesthesia. The skin and subcutaneous tissue defects were reconstructed with a posterior gluteal-thigh propeller flap, and a sigmoid colostomy was created. The patient had a good postoperative course and was transferred to a rehabilitation facility 28 days after the surgery. Epidermal cysts are a common benign tumor, and clinicians should keep in mind that these cysts can become malignant

Temporary External External Fixation Can Stabilize Hip Transposition Arthroplasty After Resection of Malignant Periacetabular Bone Tumors

Background: The choice of reconstructive procedure to restore limb function is challenging after internal hemipelvectomy. Hip transposition arthroplasty, also known as resection arthroplasty, removes a malignant or aggressive tumor of the pelvis and acetabulum after which the remaining femoral head is moved proximally to the lateral surface side of the sacrum or the underside of the resected ilium after internal hemipelvectomy. It may provide reasonable functional results and have some advantages such as lowering the risk of an infected implant compared with other reconstructions because no foreign implants are used. Hip transposition is generally managed with prolonged bed rest or immobilization postoperatively to stabilize the soft tissue surrounding the remaining femur. Because enabling patients to be mobile while the soft tissues heal might be advantageous, we reviewed our experience with an external fixation for this procedure. Questions/purposes: (1) Does temporary external fixation facilitate postoperative physiotherapy in patients who undergo hip transposition arthroplasty? (2) What functional Musculoskeletal Tumor Society (MSTS) scores were achieved at short term in a small series of patients treated with hip transposition and temporary external fixation? (3) What were the complications of using external fixation in a small series of patients who received it for malignant tumors? Methods: Between 2008 and 2012, we treated seven patients (three men and four women; median age, 37 years; age range, 18-53 years) with acetabular resection for malignant bone tumors; all were managed with a hip transposition, initially stabilized using external fixation. No other types of procedures were used for this indication in this period. Minimum followup in this retrospective study was 45 months, except for one patient who died at 18 months (range of followup duration, 18-90 months; median followup, 57 months), and no patients were lost to followup. The pins for external fixation were inserted into the affected side of the femur and the healthy contralateral ilium. External fixation was removed 6 weeks postoperatively and weightbearing was started at that time. Preoperative chemotherapy was administrated in four patients, but postoperative chemotherapy was delayed since it was given after external fixation removal in three patients. The postoperative rehabilitation course and functional results were assessed by chart review, functional results were determined using MSTS scores, tallied by physiotherapists who were not part of the surgical team, and complications were ascertained through chart review. Major complications were defined as complications that were treated with additional operations, such as deep infection, or ones that could cause severe postoperative dysfunction, such as nerve injury. Results: With temporary external fixation, standing next to a bed was achieved in median 7 days (range, 6-9 days) postoperatively, transferring to a wheel chair in median 8 days (range, 6-28 days), and gait training using parallel bars in median 15 days (range, 7-48 days). At most recent followup, three patients could walk without a crutch or cane, three could walk with a cane, and one could walk with a crutch. The median MSTS score at most recent followup (median, 57 months) was 63%. Two patients had complications that resulted in reoperations; one had a wound dehiscence, and one had an abdominal herniation that gradually developed, and which was reconstructed using polypropylene mesh 2 years after pelvic resection. Two patients had nerve palsies that recovered by the end of the first year. All patients had pin tract infections that resolved with nonsurgical approaches. Conclusions: Hip transposition with temporary external fixation can stabilize the bone soft tissue after pelvic resection. Although we did not have a comparison group of patients, we believe that external fixation facilitates early postoperative physiotherapy and rehabilitation and provides good functional results without major surgical complications. Because it delays the resumption of chemotherapy, more patients with longer followup are needed to determine whether this will be associated with poorer oncologic results

Reconstruction With Ipsilateral Fibula Transfer With Pasteurized Bone After Excision of Bone Sarcoma of the Tibia

We report a technique of implantation of the ipsilateral vascularized fibula with pasteurized recycled bone after excision of tibia sarcoma in two cases. Plate and screws were used for osteosynthesis of the tibia or talus, vascularized fibula, and pasteurized bone. Microsurgery is not necessary for this reconstruction technique. Two patients who underwent this technique have obtained good functional results without tumor relapse 5 and 6 years after operation. The technique produced excellent results with regard to tibial reconstruction in these cases. We found it to be simple, speedy, safe, and a low cost technique by use of recycled bone

Non-Destructive Imaging of Breakdown Process in Ferroelectric Capacitors Using \textit{In-situ} Laser-Based Photoemission Electron Microscopy

HfO$_2$-based ferroelectrics are one of the most actively developed functional materials for memory devices. However, in HfO$_2$-based ferroelectric devices, dielectric breakdown is a main failure mechanism during repeated polarization switching. Elucidation of the breakdown process may broaden the scope of applications for the ferroelectric HfO$_2$. Here, we report direct observations of a breakdown process in HfO$_2$-based ferroelectric capacitors, by \textit{in-situ} laser-based photoemission electron microscopy (laser-PEEM). We have not only clearly visualized the hard dielectric breakdown (HDB) spot, but also observed the regions responsible for the soft dielectric breakdown (SDB) which is a precursor phenomenon to HDB. It was found that the low-resistance region formed after SDB is wider than the conduction path formed after HDB. Furthermore, our spectromicroscopic analysis revealed that the photoelectron spectrum after SDB shows an enhancement in intensity without spectral-shape modulation, interpreted that the initially existed defects are increased. In the HDB spot, however, an additional shoulder structure was observed. These results provide spectroscopic evidence that the electronic states responsible for the conduction path after SDB are different from those after HDB. Through this work, we propose this microscopic approach as a versatile tool for studying buried materials as they are, accelerating the development of material engineering for advanced electronic devices.Comment: 6 page

Effect of bacterium in the malignant wounds of soft tissue sarcoma

Malignant wounds (MWs) are rare skin lesions, which accompany ulceration, necrosis and infection caused by infiltration or damage by malignant tumor. The present study aimed to investigate the bacterial etiology implicated in MW in soft tissue sarcoma (STS), and the effectiveness of culture‑guided perioperative antibacterial administration. A retrospective evaluation was conducted on medical records of patients who presented with MW between 2006 and 2020. A total of seven patients were included in the present study, in whom all tumors were relatively large (>5 cm) and high‑grade. Subsequently, five patients underwent limb‑sparing surgery, and three patients had distant metastases with a 5‑year overall survival of 71%. Preoperative microbiological sampling from the wound identified 11 different bacterial strains in five patients. The infections were polymicrobial with an average of 2.6 strains isolated per patient (1 aerobic, 1.6 anaerobic bacteria). They were predominantly methicillin‑sensitive Staphylococcus aureus. Patients with MWs from STS reported symptoms, including bleeding (71%), exudation (71%) and malodorous wound (43%) at the initial presentation; these completely resolved after surgery. All but one patient reported pain at the MW site with an average numeric rating scale of 4.4 at presentation that decreased to 1.4 (P=0.14) and 0.6 (P=0.04) one and two weeks after surgery, respectively. The patients had elevated C‑reactive protein (71%), anemia (57%), low albumin (86%) and renal/liver dysfunction (14‑29%). One patient was diagnosed with sepsis. Surgical resection afforded symptomatic relief and resolution of abnormal laboratory values. Although selected antibiotics were administered in four patients based on the preoperative antibiotic sensitivity test, surgical site infection (SSI) occurred in three patients. Therefore, the effectiveness of the selected antibiotics based on the results of the preoperative culture in preventing SSI needs to be investigated in the future. In conclusion, physicians should keep in mind that although surgical resection can improve the symptoms and abnormal values in laboratory examination form MW, it is accompanied with a high rate of SSI and poor prognosis