188 research outputs found

    Central nervous system mature teratoma producing carbohydrate antigen 19-9: illustrative case

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    BACKGROUND: Central nervous system (CNS) mature teratoma is a rare disease with symptoms that can vary according to tumor location. Most lesions are benign; rarely, malignancy can develop in any of the somatic components. Elevated levels of tumor markers such as α-fetoprotein and β-human chorionic gonadotropin are not usually found in patients with CNS mature teratoma, and no reports have described an association with carbohydrate antigen 19-9 (CA19-9). OBSERVATIONS: A 64-year-old woman with headache was found to have a mass lesion in the anterior cranial fossa. Magnetic resonance imaging of the brain suggested a mature teratoma. Serum and cerebrospinal fluid (CSF) tests showed significant CA19-9 elevations (2, 770 U/mL and 4, 387 U/mL, respectively). Other examinations, including whole-body 18F-fluorodeoxyglucose positron emission tomography, did not detect the origin of elevated CA19-9, suggesting that the high CA19-9 levels were caused by intracranial tumor. The patient underwent tumor removal. The histopathological diagnosis was mature teratoma with positive CA19-9 staining. CA19-9 levels in serum and CSF decreased significantly after tumor removal. LESSONS: The histopathological findings and postoperative decreased CA19-9 levels established the diagnosis of CA19-9-producing CNS mature teratoma. CNS mature teratoma can cause elevations in CA19-9 in cases with absence of neoplasms in the trunk

    Security Impact Analysis of Degree of Field Extension in Lattice Attacks on Ring-LWE Problem

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    Modern information communications use cryptography to keep the contents of communications confidential. RSA (Rivest-Shamir-Adleman) cryptography and elliptic curve cryptography, which are public-key cryptosystems, are widely used cryptographic schemes. However, it is known that these cryptographic schemes can be deciphered in a very short time by Shor's algorithm when a quantum computer is put into practical use. Therefore, several methods have been proposed for quantum computer-resistant cryptosystems that cannot be cracked even by a quantum computer. A simple implementation of LWE-based lattice cryptography based on the LWE (Learning With Errors) problem requires a key length of O(n2)O(n^2) to ensure the same level of security as existing public-key cryptography schemes such as RSA and elliptic curve cryptography. In this paper, we attacked the Ring-LWE (RLWE) scheme, which can be implemented with a short key length, with a modified LLL (Lenstra-Lenstra-Lov\'asz) basis reduction algorithm and investigated the trend in the degree of field extension required to generate a secure and small key. Results showed that the lattice-based cryptography may be strengthened by employing Cullen or Mersenne prime numbers as the degree of field extension.Comment: accepted in COMPSAC 2023 Workshop DSML: The 1st IEEE International Workshop on Data Science & Machine Learning for Cybersecurity, IoT & Digital Forensic

    FEDSM2003-45101 STUDY ON PERFORMANCE AND INTERNAL FLOW OF CROSS FLOW WIND TURBINE

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    ABSTRACT The wind turbine has become more popular in recent years, but on the other hand, the developments of small wind-turbine have been legging behind. Because, the energy density of wind is small, since the efficiency of the main part of a wind turbine is very low. The construction costs become comparatively highpriced. Then, the main part of this subject is to show that, by collecting and sucking out more winds, a wind turbine is made to pass many winds and the new cross-flow wind turbine that increases an output coefficient is proposed. The cross-flow wind turbine has high torque and low speed characteristics and the structure are very simple. So, it can be used in a large wind velocity region. However, even if the power coefficient is high, it is about 10%. The purpose of this paper is to show how we can improve the power coefficient by applying a casing, which has a nozzle and a diffuser. This research was made to clear up fundamental characteristics of the interaction between outer flow and inner flow. Three kinds of cross-flow wind turbines were designed. The nozzle and diffuser have been designed suitable for the performance of wind turbine. The flow simulations by CFD have been carried out for various types of casings at 20 m/s with Fluent Ver5.0. All Wind tunnel experiments were performed at 20m/s. The case of casing 2, which have plate arranged near the separation point of cylinder, also experimented. The rotor that is settled in the casing 1 shows a larger power coefficient than the case without a casing. The casing of the cross-flow turbine makes a pressure difference between inflow and outflow. The pressure difference increases the mass flow rate. Therefore much more wind passes through into the cross-flow turbine. In this experiment, the power coefficient increased 1.5 times in the case with casing. A still higher output coefficient could be obtained in the case where it is shown by the casing 2

    Irinotecan Hydrochloride (CPT-11) in Dialysis Patients with Gastrointestinal Cancer

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    We investigated changes in drug disposition and toxicities with CPT-11 in 15 dialysis patients with gastrointestinal cancers to clarify whether CPT-11 could be administered safely in such patients. For comparison, the same parameters were also investigated in 10 cancer patients not undergoing dialysis. Items investigated included (1) plasma concentrations of SN-38, SN-38G and CPT-11 at 0, 1, 12, 24, 36, 48 and 72h after administration, together with a comparison of mean AUC values for 3 dose levels of CPT-11 (50, 60 and 70mg/m2) in dialysis patients and controls;and (2) occurrence of adverse events. Several findings emerged from this study:(1) No significant difference was observed in the AUC for SN-38 or CPT-11 between the dialysis and control groups;(2) The AUC for SN-38G at each dose was significantly higher in dialysis patients;and (3) Grade 1-4 leucopenia was observed in 11 of the dialysis patients. One patient developed grade 4 leucopenia and died due to sepsis. Anorexia, diarrhea, nausea, alopecia and interstitial pneumonia occurred in 6 dialysis patients. We found changes in drug dispositions of CPT-11, SN-38 and SN-38G in dialysis patients, suggesting that hepatic excretion, especially that of SN-38G, was increased. No significant difference in occurrence of adverse events was observed between the 2 groups. This indicates that CPT-11 can be administered safely in patients on dialysis.</p

    Structural and dynamic behavior of lithium iron polysulfide Li₈FeS₅ during charge–discharge cycling

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    Lithium sulfide (Li₂S) is one of the promising positive electrode materials for next-generation rechargeable lithium batteries. To improve the electrochemical performance of electronically resistive Li₂S, a Fe-doped Li₂S-based positive electrode material (Li₈FeS₅) has been recently designed and found to exhibit excellent discharge capacity close to 800 mAh g⁻¹. In the present study, we investigate the structural and dynamic behavior of Li₈FeS₅ during charge–discharge cycling. In Li₈FeS₅, Fe ions are incorporated into the Li₂S framework structure. The Li₂S-based structure is found to transform to an amorphous phase during the charge process. The delithiation-induced amorphization is associated with the formation of S-S polysulfide bonds, indicating charge compensation by S ions. The crystalline to non-crystalline structural transformation is reversible, but Li ions are extracted from the material via a two-phase reaction, although they are inserted via a single-phase process. These results indicate that the delithiation/lithiation mechanism is neither a topotactic extraction/insertion nor a conversion-type reaction. Moreover, the activation energies for Li ion diffusion in the pristine, delithiated, and lithiated materials are estimated to be in the 0.30–0.37 eV range, which corresponds to the energy barriers for local hopping of Li ions along the Li sublattice in the Li₂S framework

    Malignant transformation of central neurocytoma with dissemination 17 years after initial treatment: illustrative case

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    BACKGROUND: Central neurocytomas usually have a favorable clinical course, and gross total resection (GTR) results in long-term survival. Recurrences of central neurocytomas are usually local, and dissemination is extremely rare. OBSERVATIONS: A 24-year-old man who presented with vomiting was found to have a mass in the right lateral ventricle. After GTR, he received whole-brain irradiation and chemotherapy and had remained disease-free on follow-up for years. The review of the initial tumor revealed central neurocytoma. Seventeen years later, he presented with deterioration of memory, and magnetic resonance imaging showed an enhanced lesion in the left hippocampus. The enhanced lesion was resected, and the histological examination revealed that the tumor was a disseminated atypical central neurocytoma with frequent mitoses. Although he was treated with chemotherapy, the disseminated tumor slowly grew and invaded the brain. Massive brain invasion occurred without enhanced lesions, and he died 27 months after the tumor recurrence. LESSONS: In this patient, a central neurocytoma disseminated after an extremely long period of time. Once neurocytomas disseminate and show aggressive behavior, patients usually follow a poor course. Patients with central neurocytomas should be followed up for a long time
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