SLOPT: Bandit Optimization Framework for Mutation-Based Fuzzing

Mutation-based fuzzing has become one of the most common vulnerability discovery solutions over the last decade. Fuzzing can be optimized when targeting specific programs, and given that, some studies have employed online optimization methods to do it automatically, i.e., tuning fuzzers for any given program in a program-agnostic manner. However, previous studies have neither fully explored mutation schemes suitable for online optimization methods, nor online optimization methods suitable for mutation schemes. In this study, we propose an optimization framework called SLOPT that encompasses both a bandit-friendly mutation scheme and mutation-scheme-friendly bandit algorithms. The advantage of SLOPT is that it can generally be incorporated into existing fuzzers, such as AFL and Honggfuzz. As a proof of concept, we implemented SLOPT-AFL++ by integrating SLOPT into AFL++ and showed that the program-agnostic optimization delivered by SLOPT enabled SLOPT-AFL++ to achieve higher code coverage than AFL++ in all of ten real-world FuzzBench programs. Moreover, we ran SLOPT-AFL++ against several real-world programs from OSS-Fuzz and successfully identified three previously unknown vulnerabilities, even though these programs have been fuzzed by AFL++ for a considerable number of CPU days on OSS-Fuzz.Comment: To appear in Proceedings of the 2022 Annual Computer Security Applications Conference (ACSAC '22

Thoracoscopic esophagectomy was effective in a case of lower esophageal stenosis due to recurrence of achalasia after myotomy 40 years previously

When planning surgery for achalasia, it is important to plan for adequate myotomy and prevention of reflux. However, achalasia may recur if the procedure was inadequate or in patients with a long-term course. The present case is a 68-year-old woman who underwent myotomy of the lower esophageal sphincter 40 years ago, but recently reported difficulty in swallowing. Dilatation of the thoracic esophagus and stenosis of the abdominal esophagus were identified by examination, and the patient was diagnosed with recurrence of achalasia. After percutaneous endoscopic gastrostomy was performed to recover nutritional status, thoracoscopic esophagectomy was carried out. The patient'spost-operative course was uneventful and oral intake was enabled. At the time of writing, there has been no re-recurrence. There is no standard therapy for post-operative recurrence of achalasia. We believe that thoracoscopic esophagectomy for the recurrence of achalasia is a safe and minimally invasive alternative to conventional surgery

Thoracoscopic esophagectomy was effective in a case of lower esophageal stenosis due to recurrence of achalasia after myotomy 40 years previously

When planning surgery for achalasia, it is important to plan for adequate myotomy and prevention of reflux. However, achalasia may recur if the procedure was inadequate or in patients with a long-term course. The present case is a 68-year-old woman who underwent myotomy of the lower esophageal sphincter 40 years ago, but recently reported difficulty in swallowing. Dilatation of the thoracic esophagus and stenosis of the abdominal esophagus were identified by examination, and the patient was diagnosed with recurrence of achalasia. After percutaneous endoscopic gastrostomy was performed to recover nutritional status, thoracoscopic esophagectomy was carried out. The patient'spost-operative course was uneventful and oral intake was enabled. At the time of writing, there has been no re-recurrence. There is no standard therapy for post-operative recurrence of achalasia. We believe that thoracoscopic esophagectomy for the recurrence of achalasia is a safe and minimally invasive alternative to conventional surgery

Best Thermoelectric Efficiency of Ever-Explored Materials

A thermoelectric device is a heat engine that directly converts heat into electricity. Many materials with a high figure of merit ZT have been discovered in anticipation of a high thermoelectric efficiency. However, there has been a lack of investigations on efficiency-based material evaluation, and little is known about the achievable limit of thermoelectric efficiency. Here, we report the highest thermoelectric efficiency using 13,353 published materials. The thermoelectric device efficiencies of 808,610 configurations are calculated under various heat-source temperatures (T_h) when the cold-side temperature is 300 K, solving one-dimensional thermoelectric integral equations with temperature-dependent thermoelectric properties. For infinite-cascade devices, a thermoelectric efficiency larger than 33% (~1/3) is achievable when T_h exceeds 1400 K. For single-stage devices, the best efficiency of 17.1% (~1/6) is possible when T_h is 860 K. Leg segmentation can overcome this limit, delivering a very high efficiency of 24% (~1/4) when T_h is 1100 K.Comment: 32 pages (main+table+figure captions+figures), 7 additional pages for 6 high resolution figures, Supporting Data file is not public ye

Laparoscopic Synchronous Resection for Descending Colon Cancer and Tailgut Cyst

A 67-year-old woman underwent polypectomy for a tumor at the descending colon. Pathologically, the tumor was diagnosed as adenocarcinoma with an invasion of 2000 μm. Computed tomography showed a swollen paracolic lymph node and a mass lesion in the presacral space. Magnetic resonance imaging revealed a multio-cular cystic lesion. On diagnosis of descending colon cancer and tailgut cyst, she underwent synchronous lapa-roscopic resection. Histopathologically, the colon cancer was diagnosed as pT1bN1M0, pStage IIIa. The pre-sacral cystic lesion was diagnosed as a nonmalignant tailgut cyst with negative surgical margin. The patient is currently doing well without recurrence at 28 months

Conventional Cancer Therapies Can Accelerate Malignant Potential of Cancer Cells by Activating Cancer-Associated Fibroblasts in Esophageal Cancer Models

Esophageal cancer is one of the most aggressive tumors, and the outcome remains poor. One contributing factor is the presence of tumors that are less responsive or have increased malignancy when treated with conventional chemotherapy, radiotherapy, or a combination of these. Cancer-associated fibroblasts (CAFs) play an important role in the tumor microenvironment. Focusing on conventional cancer therapies, we investigated how CAFs acquire therapeutic resistance and how they affect tumor malignancy. In this study, low-dose chemotherapy or radiotherapy-induced normal fibroblasts showed enhanced activation of CAFs markers, fibroblast activation protein, and α-smooth muscle actin, indicating the acquisition of malignancy in fibroblasts. Furthermore, CAFs activated by radiotherapy induce phenotypic changes in cancer cells, increasing their proliferation, migration, and invasion abilities. In in vivo peritoneal dissemination models, the total number of tumor nodules in the abdominal cavity was significantly increased in the co-inoculation group of cancer cells and resistant fibroblasts compared to that in the co-inoculation group of cancer cells and normal fibroblasts. In conclusion, we demonstrated that conventional cancer therapy causes anti-therapeutic effects via the activation of fibroblasts, resulting in CAFs. It is important to select or combine modalities of esophageal cancer treatment, recognizing that inappropriate radiotherapy and chemotherapy can lead to resistance in CAF-rich tumors