473 research outputs found

    Unveiling the double-peak structure of quantum oscillations in the specific heat

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    Quantum oscillation phenomenon is an essential tool to understand the electronic structure of quantum matter. Here we report the first systematic study of quantum oscillations in the electronic specific heat CelC_{el} in natural graphite. We show that the crossing of a single spin Landau level and the Fermi energy give rise to a double-peak structure, in striking contrast to the single peak expected from Lifshitz-Kosevich theory. Intriguingly, the double-peak structure is predicted by the kernel term for Cel/TC_{el}/T in the free electron theory. The Cel/TC_{el}/T represents a spectroscopic tuning fork of width 4.8 kBTk_B T which can be tuned at will to resonance. Using a coincidence method, the double-peak structure can be used to accurately determine the Lande gg-factor of quantum materials. More generally, the tuning fork can be used to reveal any peak in fermionic density of states tuned by magnetic field, such as Lifshitz transition in heavy-fermion compounds.Comment: 22 pages, 5 figure

    Phosphorylation of centromeric histone H3 variant regulates chromosome segregation in S. cerevisiae

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    The centromeric histone H3 variant (CenH3) is essential for chromosome segregation in eukaryotes. We have identified posttranslational modifications of S. cerevisiae CenH3, Cse4. Functional characterization of cse4 phosphorylation mutants showed growth and chromosome segregation defects when combined with kinetochore mutants okp1 and ame1. Using a phosphoserine-specific antibody we showed that the association of phosphorylated Cse4 with centromeres is increased in response to defective microtubule attachment or reduced cohesion. We determined that evolutionarily conserved Ipl1/Aurora B contributes to phosphorylation of Cse4, as levels of phosphorylated Cse4 were reduced at centromeres in ipl1 strains in vivo and in vitro assays showed phosphorylation of Cse4 by Ipl1. Consistent with these results we observed that a phosphomimetic cse4-4SD mutant suppressed the temperature sensitive growth of ipl1-2 and Ipl1 substrate mutants dam1 spc34 and ndc80 that are defective for chromosome biorientation. Furthermore, cell biology approaches using a GFP labeled chromosome showed that cse4-4SD suppressed chromosome segregation defects in dam1 spc34 strains. Based these results we propose that phosphorylation of Cse4 destabilizes defective kinetochores to promote biorientation and ensure faithful chromosome segregation. Taken together, our study provides a detailed analysis, in vivo and in vitro, of Cse4 phosphorylation and its role in promoting faithful chromosome segregation

    Consensus report from the 8th International Forum for Liver Magnetic Resonance Imaging.

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    ObjectivesThe 8th International Forum for Liver Magnetic Resonance Imaging (MRI), held in Basel, Switzerland, in October 2017, brought together clinical and academic radiologists from around the world to discuss developments in and reach consensus on key issues in the field of gadoxetic acid-enhanced liver MRI since the previous Forum held in 2013.MethodsTwo main themes in liver MRI were considered in detail at the Forum: the use of gadoxetic acid for contrast-enhanced MRI in patients with liver cirrhosis and the technical performance of gadoxetic acid-enhanced liver MRI, both opportunities and challenges. This article summarises the expert presentations and the delegate voting on consensus statements discussed at the Forum.Results and conclusionsIt was concluded that gadoxetic acid-enhanced MRI has higher sensitivity for the diagnosis of hepatocellular carcinoma (HCC), when compared with multidetector CT, by utilising features of hyperenhancement in the arterial phase and hypointensity in the hepatobiliary phase (HBP). Recent HCC management guidelines recognise an increasing role for gadoxetic acid-enhanced MRI in early diagnosis and monitoring post-resection. Additional research is needed to define the role of HBP in predicting microvascular invasion, to better define washout during the transitional phase in gadoxetic acid-enhanced MRI for HCC diagnosis, and to reduce the artefacts encountered in the arterial phase. Technical developments are being directed to shortening the MRI protocol for reducing time and patient discomfort and toward utilising faster imaging and non-Cartesian free-breathing approaches that have the potential to improve multiphasic dynamic imaging.Key points• Gadoxetic acid-enhanced MRI provides higher diagnostic sensitivity than CT for diagnosing HCC. • Gadoxetic acid-enhanced MRI has roles in early-HCC diagnosis and monitoring post-resection response. • Faster imaging and free-breathing approaches have potential to improve multiphasic dynamic imaging

    An unusual association of diffuse adenomyomatosis with dysplastic adenoma in chronic calculous cholecystitis: case presentation

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    <p>Abstract</p> <p>Background</p> <p>Gallbladder adenomyomatosis is an epithelial proliferation and hypertrophy of the muscularis mucosae of the gallbladder. Rokitansky-Aschoff sinuses are a characteristic of this condition. The segmental adenomyomatosis has a higher risk of developing into gallbladder carcinoma, especially in the fundal region of elderly patients.</p> <p>We report the case of a patient affected by chronic calculous cholecystitis with diffuse adenomyomatosis associated with dysplastic adenoma.</p> <p>Case presentation</p> <p>An 81-year-old woman presented at our hospital with a 1-year history of intermittent pain localized at the right upper abdominal quadrant, without diffusion to any other body part. On physical examination the abdomen was soft, not distended, and tender to palpation in the right upper quadrant. Murphy sign was negative. Laboratory tests were normal. The patient was scheduled for a laparoscopic cholecystectomy, and neither endoscopic ultrasonographic scan nor magnetic resonance imaging was performed. The operation, performed after obtaining informed consent, was uncomplicated and the intra-operative pathological examination showed no malignancy. The definitive pathological examination of the gallbladder showed: multiple stones of cholesterol origin; diffuse mucosal adenomyomatosis; and a 1.1 cm pedunculated mass localized at the fundus, whose surface was lumpy. This mass was diagnosed as an adenoma with multiple areas of severe dysplasia.</p> <p>Conclusions</p> <p>The adenoma of the gallbladder, together with the dysplasia, represents a biological carcinogenetic model. Carcinoma has rarely been reported in adenomyomatosis. Degenerative risk suggests surgery should be mandatory when there is a concomitant presence of large adenoma and adenomyomatosis.</p

    Follow-up nationwide survey on predictive genetic testing for late-onset hereditary neurological diseases in Japan

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    A follow-up nationwide survey on predictive genetic testing for late-onset neurological diseases in Japan was conducted. A questionnaire was sent to 89 institutional members of the Japan's National Liaison Council for Clinical Sections of Medical Genetics, and was returned by 60 (67.4%). A total of 301 clients with an interest in predictive testing were accumulated from April 2006 to March 2011. The greatest interest was shown for spinocerebellar degeneration (SCD, n = 110), followed by myotonic dystrophy type 1 (DM1, n = 69), Huntington's disease (HD, n = 52) and familial amyloid polyneuropathy (FAP, n = 35). The ratios of clients who actually underwent predictive testing were: SCD, 21.8%; DM1, 39.1%; HD, 26.9%; and FAP, 74.3%, indicating that predictive testing was conducted very cautiously for untreatable neurological diseases in Japan. Clinical geneticists were predominantly involved in genetic counseling, whereas the participation of non-medical doctor (non-MD) staff, including nurses, clinical psychologists and genetic counselors, was not common. Lack of non-MD counseling staff was one of the most serious issues in conducting predictive testing, which has not been improved since the previous survey performed in 2006. Institutional arrangements, such as revision of medical insurance system regarding genetic testing and counseling, might be necessary to resolve this issue.ArticleJOURNAL OF HUMAN GENETICS. 58(8):560-563 (2013)journal articl

    Relationship between silent brain infarction and chronic kidney disease

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    Background. The presence of silent brain infarction (SBI) increases the risk of symptomatic stroke and dementia. The association between SBI and chronic kidney disease (CKD) has not been clarified. Moreover, little is known about what factors are related to SBI in CKD patients and whether the prevalence of SBI differs in CKD stage or cause of CKD
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