238 research outputs found
New physics for muon anomalous magnetic moment and its electroweak precision analysis
About 3 sigma deviation from the standard model prediction of muon anomalous
magnetic moment (muon g-2) has been reported. We consider new physics beyond
the standard model which has new Yukawa interactions with muon. We compute new
contributions to muon g-2 and corrections to electroweak observables, and show
the consistent region of parameter space. We find that in a simple model where
the chirality flip of muon occurs only in the external muon line in one-loop
muon g-2 diagrams, it is necessary to introduce the relatively large new Yukawa
coupling and the electroweak scale new particles. On the other hand, in a model
where the chirality flip can occur in the internal fermion line of one loop
muon g-2 diagrams, we can obtain favorable g-2 contributions without large
Yukawa coupling, and they are consistent with the precision electroweak
observables. Finally, we discuss effects of new particles for muon g-2 on the
Higgs boson decay h to 2 photons and direct productions of these particles at
the LHC experiment.Comment: 31 pages, 20 figure
Updated absolute gravity rate of change associated with glacial isostatic adjustment in Southeast Alaska and its utilization for rheological parameter estimation
In Southeast Alaska (SE-AK), rapid ground uplift of up to 3 cm/yr has been observed associated with post-Little Ice Age glacial isostatic adjustment (GIA). Geodetic techniques such as global navigation satellite system (GNSS) and absolute gravimetry have been applied to monitor GIA since the last 1990s. Rheological parameters for SE-AK were determined from dense GNSS array data in earlier studies. However, the absolute gravity rate of change observed in SE-AK was inconsistent with the ground uplift rate, mainly because few gravity measurements from 2006 to 2008 resulted in imprecise gravity variation rates. Therefore, we collected absolute gravity data at six gravity points in SE-AK every June in 2012, 2013, and 2015, and updated the gravity variation rate by reprocessing the absolute gravity data collected from 2006 to 2015. We found that the updated gravity variation rate at the six gravity points ranged from −2.05 to −4.40 μGal/yr, and its standard deviation was smaller than that reported in the earlier study by up to 88 %. We also estimated the rheological parameters under the assumption of the incompressible Earth to explain the updated gravity variation rate, and their optimal values were determined to be 55 km and 1.2×10¹⁹ Pa s for lithospheric thickness and upper mantle viscosity, respectively. These optimal values are consistent with those independently obtained from GNSS observations, and this fact indicates that absolute gravimetry can be one of the most effective methods in determining sub-surface structural parameters associated with GIA accurately. Moreover, we utilized the gravity variation rates for estimating the ratio of gravity variation to vertical ground deformation at the six gravity points in SE-AK. The viscous ratio values were obtained as −0.168 and −0.171 μGal/mm from the observed data and the calculated result, respectively. These ratios are greater (in absolute) than those for other GIA regions (−0.15 to −0.16 μGal/mm in Antarctica and Fennoscandia), because glaciers in SE-AK have melted more recently than in other regions
Ataxia and peripheral nerve hypomyelination in ADAM22-deficient mice
BACKGROUND: ADAM22 is a member of the ADAM gene family, but the fact that it is expressed only in the nervous systems makes it unique. ADAM22's sequence similarity to other ADAMs suggests it to be an integrin binder and thus to have a role in cell-cell or cell-matrix interactions. To elucidate the physiological functions of ADAM22, we employed gene targeting to generate ADAM22 knockout mice. RESULTS: ADAM22-deficient mice were produced in a good accordance with the Mendelian ratio and appeared normal at birth. After one week, severe ataxia was observed, and all homozygotes died before weaning, probably due to convulsions. No major histological abnormalities were detected in the cerebral cortex or cerebellum of the homozygous mutants; however, marked hypomyelination of the peripheral nerves was observed. CONCLUSION: The results of our study demonstrate that ADAM22 is closely involved in the correct functioning of the nervous system. Further analysis of ADAM22 will provide clues to understanding the mechanisms of human diseases such as epileptic seizures and peripheral neuropathy
Ferrocenylnaphthalene Diimide-Based Electrochemical Detection of Aberrant Methylation in hTERT Gene
Since aberrant methylation at CpG sites is linked to the silencing of tumor suppressor genes, DNA methylation analysis is important for cancer diagnosis. We developed ferrocenylnaphthalene diimide (FND), which has two ferrocenyl moieties at the substituent termini, as an electrochemical indicator for hybridized DNA duplexes. In this study, we attempted to detect aberrant methylation of human telomerase reverse transcriptase gene (hTERT), an efficient cancer marker, using FND-based hybridization coupled with electrochemical detection via a multi-electrode chip
Screening for Oral Cancer Using Electrochemical Telomerase Assay
Electrochemical telomerase assay (ECTA) developed by our group was evaluated in an oral cancer screening using exfoliated oral cells and tissues obtained from patients of oral cancer, mucosa associated disease, or healthy volunteers. Telomerase activity from ECTA is correlated with hTERT mRNA expression level using a real‐time PCR and was increasing in the following order: healthy volunteer group<mucosa associated disease group<oral cancer group. Sensitivity and specificity of ECTA were 88% and 72%, respectively when used 17% of the threshold value based on the receiver operating characteristic curve in ECTA data
Electrochemical telomerase assay for screening for oral cancer
Telomerase has long been known to be a marker for cancer. We have developed a new method of detecting it: the electrochemical telomerase assay (ECTA). We have previously confirmed that the assay is easier to do and more precise than the conventional telomeric repeat amplification protocol, which is currently the most widely used. Here we describe a pilot study made to establish a screening system for oral cancer using ECTA. We evaluated three types of clinical samples obtained from 44 patients with oral cancer and 26 healthy volunteers: exfoliated cells from the whole oral cavity, exfoliated cells from local lesions, and tissue from the lesion itself. The current increase ratio (Δi) obtained by ECTA was significantly higher in the oral cancer group for each type of sampling used. The threshold value for Δi was 19% when calculated by analysis of receiver-operating characteristic curves. Sensitivity and specificity values were 86% and 85% for cells from the oral cavity, 82% and 85% in cells from local lesions, and 95% and 92% in cells from the tumour itself, respectively. There were also no significant differences in sensitivity and specificity associated with age, size of tumour, site of lesion, or degree of malignancy. ECTA therefore seems to be a promising assay for screening for oral cancer
- …