Random telegraph noise in metallic single-walled carbon nanotubes

We have investigated random telegraph noise (RTN) observed in individual metallic carbon nanotubes (CNTs). Mean lifetimes in high- and low-current states, shigh and slow, have been studied as a function of bias-voltage and gate-voltage as well as temperature. By analyzing the statistics and features of the RTN, we suggest that this noise is due to the random transition of defects between two metastable states, activated by inelastic scattering with conduction electrons. Our results indicate an important role of defect motions in the 1=f noise in CNTs.Comment: 4 page

Positive Result in the Early Passive Phase of the Tilt-table Test: A Predictor of Neurocardiogenic Syncope in Young Men

Background/Aims: This study elucidated the prognostic factors for neurocardiogenic syncope in males in their late teens and early twenties. Methods: Tilt-table testing (TTT) was performed on 665 males (age range, 17 to 27 years) following the Italian protocol. The subjects were tilted head-up at a 70 ° angle on a table for 30 minutes during the passive phase. If the passive phase was negative, the subjects were given sublingual nitroglycerin and tilted to the same angle for 20 minutes during the drugprovocation phase. The subjects with positive results were followed without medication. We analyzed factors related to the recurrence rate of syncope. Results: Of 305 subjects (45.8%) with positive results, 223 (age range, 18 to 26 years) were followed for 12 months. The frequency of previous syncopal episodes ≥ 4 (p = 0.001) and a positive result during the passive phase (p = 0.022) were significantly related to a high recurrence rate. A positive result during the early passive phase ( ≤ 12 minutes) was significantly related to a higher recurrence rate than was that during the late passive phase (> 12 minutes; p = 0.011). Conclusions: A positive result during the early passive phase of TTT and frequent previous syncopal episodes were prognostic factors for neurocardiogenic syncope in men in their late teens and early twenties. Keywords: Syncope, vasovagal; Prognosis; Tilt-table tes

Hearing recovery prediction and prognostic factors of idiopathic sudden sensorineural hearing loss: a retrospective analysis with a deep neural network model

Objective: Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) is an otologic emergency, and an early prediction of prognosis may facilitate proper treatment. Therefore, we investigated the prognostic factors for predicting the recovery in patients with ISSHL treated with combined treatment method using machine learning models. Methods: We retrospectively reviewed the medical records of 298 patients with ISSHL at a tertiary medical institution between January 2015 and September 2020. Fifty-two variables were analyzed to predict hearing recovery. Recovery was defined using Siegel’s criteria, and the patients were categorized into recovery and non-recovery groups. Recovery was predicted by various machine learning models. In addition, the prognostic factors were analyzed using the difference in the loss function. Results: There were significant differences in variables including age, hypertension, previous hearing loss, ear fullness, duration of hospital admission, initial hearing level of the affected and unaffected ears, and post-treatment hearing level between recovery and non-recovery groups. The deep neural network model showed the highest predictive performance (accuracy, 88.81%; area under the receiver operating characteristic curve, 0.9448). In addition, initial hearing level of affected and non-affected ear, post-treatment (2-weeks) hearing level of affected ear were significant factors for predicting the prognosis. Conclusion: The deep neural network model showed the highest predictive performance for recovery in patients with ISSHL. Some factors with prognostic value were identified. Further studies using a larger patient population are warranted. Level of evidence: Level 4

Changes in Parthenogenetic Imprinting Patterns during Reprogramming by Cell Fusion

<div><p>Differentiated somatic cells can be reprogrammed into the pluripotent state by cell-cell fusion. In the pluripotent state, reprogrammed cells may then self-renew and differentiate into all three germ layers. Fusion-induced reprogramming also epigenetically modifies the somatic cell genome through DNA demethylation, X chromosome reactivation, and histone modification. In this study, we investigated whether fusion with embryonic stem cells (ESCs) also reprograms genomic imprinting patterns in somatic cells. In particular, we examined imprinting changes in parthenogenetic neural stem cells fused with biparental ESCs, as well as in biparental neural stem cells fused with parthenogenetic ESCs. The resulting hybrid cells expressed the pluripotency markers <i>Oct4</i> and <i>Nanog</i>. In addition, methylation of several imprinted genes except <i>Peg3</i> was comparable between hybrid cells and ESCs. This finding indicates that reprogramming by cell fusion does not necessarily reverse the status of all imprinted genes to the state of pluripotent fusion partner.</p></div

Quantitative RT-PCR analysis of imprinted gene expression.

<p>The expression profiles of paternal and maternal imprinted genes were analyzed by real-time RT-PCR. All data are normalized to <i>ACTB</i> expression and calibrated on the ESCs, whose gene expression was considered 1 for all genes. Error bars represent mean values ± SEM of three independent experiments. Student’s t-test: ***, p<0.001; **, p<0.01; *, p<0.05.</p

Generation of fusion hybrid cells between parthenogenetic and biparental cells.

<p><b>(A)</b> GFP fluorescence images of fusion between biparental ESCs and parthenogenetic neural stem cells (ES-pNSC), and between pESCs and biparental neural stem cells (pES-NSC) at day 3 after fusion (200 ×). <b>(B)</b> GFP fluorescence images of ES-pNSC and pES-NSC hybrids after FACS sorting (100 ×). <b>(C)</b> Representative tetraploid karyotype of the hybrid cells.</p

Bisulfite genome sequencing analysis of imprinted genes.

<p>DNA methylation patterns of paternally (<i>H19</i> and <i>Igf2</i>), and maternally imprinted genes (<i>Peg1</i> and <i>Peg3</i>) in ESCs, pESCs, NSCs, pNSCs, ES-pNSC, and pES-NSC hybrid cells. Black and white circles represent methylated and unmethylated CpGs, respectively.</p

Characterization of hybrid cells.

<p><b>(A)</b> Both ES-pNSC and pES-NSC hybrid cells are positive for alkaline phosphatase staining (100 ×). <b>(B)</b> RT-PCR analysis of <i>Oct4</i>, <i>Nanog</i>, <i>Sox2</i>, and <i>Nestin</i> expression in fusion partner and reprogrammed hybrid cells. Pluripotency markers, <i>Oct4</i> and <i>Nanog</i>, which were not expressed in NSCs and pNSCs were expressed in GFP⁺ fusion hybrid cells. On the other hand, <i>Nestin</i>, which was expressed in NSCs and pNSCs was silenced after forming GFP⁺ fusion hybrid cells. <b>(C)</b> Immunocytochemistry analysis of Oct4 and Nanog in ES-pNSC and pES-NSC hybrid cells (100 ×). <b>(D)</b> <i>In vitro</i> differentiation of ES-pNSC and pES-NSC hybrid cells into ectoderm (Tuj1), mesoderm (SMA), and endoderm (Sox17) lineages (200 ×). <b>(E)</b> In vivo differentiation potential of ES-pNSC and pES-NSC hybrid cells through teratoma assay. These hybrid cells were contributed to secretory epithelium (ectoderm), cartilage (mesoderm) and gut epithelium (endoderm), which were stained with PAS, Asian blue, and hematoxylin eosin, respectively. Each tissue was indicated by arrow head.</p