Multiple Dirac fermions from a topological insulator and graphene superlattice

Graphene and three-dimensional topological insulators are well-known Dirac materials whose bulk and surface states are governed by Dirac equations. They not only show good transport properties but also carry various quanta related to the geometrical phase such as charge, spin, and valley Hall conductances. Therefore, it is a great challenge to combine the two Dirac materials together, realizing multiple Dirac fermions. By using first-principles density-functional-theory calculations, we demonstrate such a system built from topological insulator-band insulator-graphene superlattice structures. Hexagonal boron nitride is proposed as an ideal band-insulating material in gluing graphene and topological insulators, providing a good substrate for graphene and a sharp interface with a topological insulator. The power factors for p-type doping are largely enhanced due to the charge-conducting channels through multiple Dirac cones. The systems characterized by the coexistence of the topologically protected interfacial and graphene Dirac cones can pave the way for developing integrated devices for electronics, spintronics and valleytronics applications.open5

Effect of Oral Supplementation with Branched-chain Amino Acid (BCAA) during Radiotherapy in Patients with Hepatocellular Carcinoma: A Double-Blind Randomized Study

PURPOSE: The present study evaluated whether oral supplementation with a branched-chain amino acid (BCAA) improves the biochemical and amino acid profiles of liver tumor patients undergoing radiotherapy. MATERIALS AND METHODS: Patients were randomly assigned to one of 2 groups: a group given oral supplementation with BCAA granules (LIVACT granules; Samil Pharm Co., Korea, each granule containing L-isoleucine 952 mg, L-leucine 1,904 mg, and L-valine 1,144 mg) during radiotherapy, or a placebo group. Physical and biochemical examinations and measurements, including subjective symptoms, Child-Pugh class, body mass index, plasma albumin concentration, and plasma amino acid profiles were monitored. RESULTS: Fifty were enrolled between November 2005 and November 2006. We also analyzed data from 37 hepatocellular carcinoma (HCC) patients in order to evaluate a more homogenous group. The two groups of patients were comparable in terms of age, gender, Child-Pugh score, and underlying hepatitis virus type. Serum albumin, total protein, liver enzymes, and cholesterol showed a tendency to increase in the BCAA group. In this group, the percentage of cases that reverted to normal serum albumin levels between 3 and 10 weeks after administration of BCAA was significantly higher (41.18%) than in the placebo group (p=0.043). CONCLUSION: Oral supplementation with a BCAA preparation seems to help HCC patients undergoing radiotherapy by increasing the BCAA concentration.ope

Theta Oscillation Related to the Auditory Discrimination Process in Mismatch Negativity: Oddball versus Control Paradigm

Background and Purpose The aim of this study was to identify the mechanism underlying the auditory discriminatory process reflected in mismatch negativity (MMN), using time-frequency analysis of single-trial event-related potentials (ERPs).Methods Two auditory tones of different probabilities (oddball paradigm) and the same probability (control paradigm) were used. The average dynamic changes in amplitude were evaluated, and the in-phase consistency of the EEG spectrum at each frequency and time window across trials, event-related spectral perturbations (ERSPs), and inter-trial phase coherence (ITC) were computed.Results Subtraction of the ERPs of standard stimuli from the ERPs of deviant stimuli revealed a clear MMN component in the oddball paradigm. However, no discernible MMN component was observed in the control paradigm. Statistical tests showed that in the oddball paradigm, deviant tones produced significant increases of theta ERSPs and ITC at around 250 ms as compared with the standard tone, while no significant difference between the two stimuli was observed in the control paradigm.Conclusions Our results confirm that the auditory discriminatory process reflected in MMN is accompanied by phase resetting and power modulation at the theta frequency.OAIID:oai:osos.snu.ac.kr:snu2012-01/102/2014017262/2SEQ:2PERF_CD:SNU2012-01EVAL_ITEM_CD:102USER_ID:2014017262ADJUST_YN:YEMP_ID:A079623DEPT_CD:801CITE_RATE:1.892DEPT_NM:의학과SCOPUS_YN:YCONFIRM:

Binge Drinking and Its Relation to Metabolic Syndrome in Korean Adult Men

Background: It is reported that heavy drinking increases the risk of metabolic syndrome. But there have been few studies on the relationship between the intensity of drinking and metabolic syndrome when drinking the same amount of alcohol. This study aimed to assess the relationship between the frequency of binge drinking and metabolic syndrome in Korean adult men.Methods: From the database of the 4th and 5th Korea National Health and Nutrition Examination Survey conducted in 2007?2010, data of 8,305 adult men (≥19 years of age) was included in this analysis. Cross-sectional relationship between the frequency of binge drinking and metabolic syndrome was investigated adjusting for pure alcohol consumed per day.Results: Adjusting for various confounders including pure alcohol consumed per day, the adjusted odds ratio for metabolic syndrome in those in higher frequency (more than 1/wk) binge drinking group was 1.62 (95% confidence interval, 1.30 to 2.03; P for trend = <0.001) compared to those in the non-binge drinking group. Through analysis of the relationship between pure alcohol consumed per day and metabolic syndrome, it was found that pure alcohol consumed per day had a positive relation to metabolic syndrome in the higher frequency binge drinking group (P for trend = 0.041). The relationship was inverse in the non-binge drinking group (P for trend = 0.002).Conclusion: Our study found a positive relationship between frequency of binge drinking and metabolic syndrome in adult men. And the effect of drinking on metabolic syndrome may depend on the frequency of binge drinking. Further studies are required to confirm this association.OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000052039/10SEQ:10PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000052039ADJUST_YN:YEMP_ID:A079543DEPT_CD:806CITE_RATE:0FILENAME:binge drinking and its relation to metabolic syndrome in korean adult men.pdfDEPT_NM:의과학과SCOPUS_YN:NCONFIRM:

Hyperelastic, shape‐memorable, and ultra‐cell‐adhesive degradable polycaprolactone‐polyurethane copolymer for tissue regeneration

Novel polycaprolactone-based polyurethane (PCL-PU) copolymers with hyperelasticity, shape-memory, and ultra-cell-adhesion properties are reported as clinically applicable tissue-regenerative biomaterials. New isosorbide derivatives (propoxylated or ethoxylated ones) were developed to improve mechanical properties by enhanced reactivity in copolymer synthesis compared to the original isosorbide. Optimized PCL-PU with propoxylated isosorbide exhibited notable mechanical performance (50 MPa tensile strength and 1150% elongation with hyperelasticity under cyclic load). The shape-memory effect was also revealed in different forms (film, thread, and 3D scaffold) with 40%–80% recovery in tension or compression mode after plastic deformation. The ultra-cell-adhesive property was proven in various cell types which were reasoned to involve the heat shock protein-mediated integrin (α5 and αV) activation, as analyzed by RNA sequencing and inhibition tests. After the tissue regenerative potential (muscle and bone) was confirmed by the myogenic and osteogenic responses in vitro, biodegradability, compatible in vivo tissue response, and healing capacity were investigated with in vivo shape-memorable behavior. The currently exploited PCL-PU, with its multifunctional (hyperelastic, shape-memorable, ultra-celladhesive, and degradable) nature and biocompatibility, is considered a potential tissue- regenerative biomaterial, especially for minimally invasive surgery that requires small incisions to approach large defects with excellent regeneration capacity

Real-time heart rate variability according to ambulatory glucose profile in patients with diabetes mellitus

BackgroundAutonomic neuropathy commonly occurs as a long-term complication of diabetes mellitus (DM) and can be diagnosed based on heart rate variability (HRV), calculated from electrocardiogram (ECG) recordings. There are limited data on HRV using real-time ECG and ambulatory glucose monitoring in patients with DM. The aim of this study was to investigate real-time HRV according to ambulatory glucose levels in patients with DM.MethodsA total of 43 patients (66.3 ± 7.5 years) with DM underwent continuous real-time ECG monitoring (225.7 ± 107.3 h) for HRV and ambulatory glucose monitoring using a remote monitoring system. We compared the HRV according to the ambulatory glucose profile. Data were analyzed according to the target in glucose range (TIR).ResultsThere were no significant differences in the baseline characteristics of the patients according to the TIR. During monitoring, we checked ECG and ambulatory glucose levels (a total of 15,090 times) simultaneously for all patients. Both time- and frequency-domain HRVs were lower when the patients had poorly controlled glucose levels (TIR &lt; 70%) compared with well controlled glucose levels (TIR &gt; 70%). In addition, heart and respiratory rates increased with real-time glucose levels (P &lt; 0.001).ConclusionsPoorly controlled glucose levels were independently associated with lower HRV in patients with DM. This was further substantiated by the independent continuous association between real-time measurements of hyperglycemia and lower HRV. These data strongly suggest that cardiac autonomic dysfunction is caused by elevated blood sugar levels