[Microcontact printing and its application prospect in bone tissue engineering]

The application of bone tissue engineering regeneration technology is expected to repair maxillofacial bone tissue defects caused by tumors, trauma, etc. Surface patterning occupies an important position in bone tissue engineering. Microcontact printing is an emerging technology through which the elastic stamp contacts with the substance and materials used as ink can be transferred from stamp to substance to form patterns. The biggest characteristic of the technology is to fabricate high-throughput and high-accuracy patterned surface, making it widely applied. This review summarized the application and optimization of microcontact printing, and prospected its application in bone tissue engineering.

Immunogenicity study of engineered ferritins with C- and N-terminus insertion of Epstein-Barr nuclear antigen 1 epitope

Human ferritin heavy chain, an example of a protein nanoparticle, has recently been used as a vaccine delivery platform. Human ferritin has advantages of uniform architecture, robust thermal and chemical stabilities, and good biocompatibility and biodegradation. There is however a lack of understanding about the relationship between insertion sites in ferritin (N-terminus and C-terminus) and the corresponding humoral and cell-mediated immune responses. To bridge this gap, we utilized an Epstein-Barr Nuclear Antigen 1 (EBNA1) epitope as a model to produce engineered ferritin-based vaccines E1F1 (N-terminus insertion) and F1E1 (C-terminus insertion) for the prevention of Epstein-Barr virus (EBV) infections. X-ray crystallography confirmed the relative positions of the N-terminus insertion and C-terminus insertion. For N-terminus insertion, the epitopes were located on the exterior surface of ferritin, while for C-terminus insertion, the epitopes were inside the ferritin cage. Based on the results of antigen-specific antibody titers from in-vivo tests, we found that there was no obvious difference on humoral immune responses between N-terminus and C-terminus insertion. We also evaluated splenocyte proliferation and memory lymphocyte T cell differentiation. Both results suggested C-terminus insertion produced a stronger proliferative response and cell-mediated immune response than N-terminus insertion. C-terminus insertion of EBNA1 epitope was also processed more efficiently by dendritic cells (DCs) than N-terminus insertion. This provides new insight into the relationship between the insertion site and immunogenicity of ferritin nanoparticle vaccines.

Cost-effective purification process development for chimeric hepatitis B core (HBc) virus-like particles assisted by molecular dynamic simulation

Inserting foreign epitopes to hepatitis B core (HBc) virus-like particles (VLPs) could influence the molecular conformation and therefore vary the purification process. In this study, a cost-effective purification process was developed for two chimeric HBc VLPs displaying Epstein-Barr nuclear antigens 1 (EBNA1), and hepatitis C virus (HCV) core. Both chimeric VLPs were expressed in soluble form with high production yields in Escherichia coli. Molecular dynamic (MD) simulation was employed to predict the stability of chimeric VLPs. HCV core-HBc was found to be less stable in water environment compared with EBNA1-HBc, indicating its higher hydrophobicity. Assisting with MD simulation, ammonium sulfate precipitation was optimized to remove host cell proteins with high target protein recovery yields. Moreover, 99% DNA impurities were removed using POROS 50 HQ chromatography. In characterization measurement, we found that inserting HCV core epitope would reduce the ratio of α-helix of HCV core-HBc. This could be another reason on the top of its higher hydrophobicity predicted by MD simulation, causing its less stability. Tertiary structure, transmission electron microscopy, and immunogenicity results indicate that two chimeric VLPs maintained correct VLP structure ensuring its bioactivity after being processed by the developed cost-effective purification approach.

POS0320 POOR PROGNOSIS PREDICTION IN ANTI-MDA5 POSITIVE DERMATOMYOSITIS ASSOCIATED WITH INTERSTITIAL LUNG DISEASE: THE CROSS-CAR DECISION TREE MODEL

Background:

The prognosis of anti-melanoma differentiation-associated gene 5 positive dermatomyositis (anti-MDA5+ DM) – associated interstitial lung disease (ILD) is poor and heterogeneity.

Objectives:

The aim of this study was to evaluate prognostic factors and to develop a simple and generally applicable bedside decision tree model for predicting outcomes in patients with anti-MDA5+ DM and to guide treatment.

Methods:

We analyzed data for 246 anti-MDA5+ DM patients from Myositis Study Group-Jiangsu, a multicenter cohort across eighteen tertiary hospitals in Jiangsu province, from March 2019 to October 2020. The primary end point was all-cause death, and the secondary end point was occurring of rapidly progressive-ILD (rp-ILD). We used a multivariable Cox proportional hazards model to identify the independent prognostic risk factors of death and rp-ILD respectively. A decision-tree prediction model was developed by using data from 10 hospital of southern region (n=163), with validation by using contemporaneous data from northern region (n=83).

Results:

To assess the risk of rp-ILD, we developed a combined risk score, the CROSS score, that included the following values and scores: C-reactive protein (≤8mg/L, 0; >8mg/L, 3), anti-Ro52 antibody (negative, 0; positive, 4), Sex (Female, 0; Male, 2) and Short course of disease (More than 3 months, 0; Less than 3 months, 2). The mortality risk was identified by the CAR score, including C-reactive protein (≤8mg/L, 0; >8mg/L, 1), Alanine Transaminase (≤50units/L, 0; >50units/L, 1) and rp-ILD (non-rpILD, 0; rp-ILD, 3). We divided patients into three risk groups according to the CROSS score: low, 0 to 3; medium, 4 to 7; and high 8-11. And then Use of a simple decision tree prediction model permitted stratification into three different outcome prediction groups. High-risk patients had significantly higher mortality rates than low- and medium-risk patients in both discovery and validation cohorts (p < 0.0001).

Conclusion:

The CROSS-CAR decision tree model is easy to evaluate the poor prognostic risk in MDA5+ DM patients during any follow-up period. Unnecessary lung examination, such as chest CT scan and arterial blood gas analysis was avoided in low- and medium- rpILD risk patients. The special ambulance, with red cross sign tagged on car in China, may help to screen the high risk patients and to guide further treatment.

Disclosure of Interests:

None declared

Stability of Engineered Ferritin Nanovaccines Investigated by Combined Molecular Simulation and Experiments

Human ferritin is regarded as an attractive and promising vaccine platform because of its uniform structure, good plasticity, and desirable thermal and chemical stabilities. Besides, it is biocompatible and presumed safe when used as a vaccine carrier. However, there is a lack of knowledge of how different antigen insertion sites on the ferritin nanocage impact the resulting protein stability and performance. To address this question, we selected Epstein-Barr nuclear antigen 1 as a model epitope and fused it at the DNA level with different insertion sites, namely, the N- and C-termini of ferritin, to engineer proteins E1F1 and F1E1, respectively. Protein properties including hydrophobicity and thermal, pH, and chemical stability were investigated both by molecular dynamics (MD) simulation and by experiments. Both methods demonstrate that the insertion site plays an important role in protein properties. The C-terminus insertion (F1E1) leads to a less hydrophobic surface and more tolerance to the external influence of high temperature, pH, and high concentration of chemical denaturants compared to N-terminus insertion (E1F1). Simulated protein hydrophobicity and thermal stability by MD were in high accordance with experimental results. Thus, MD simulation can be used as a valuable tool to engineer nanovaccine candidates, cutting down costs by reducing the experimental effort and accelerating vaccine design.

Engineered Human Heavy-Chain Ferritin with Half-Life Extension and Tumor Targeting by PAS and RGDK Peptide Functionalization

Ferritin, one of the most investigated protein nanocages, is considered as a promising drug carrier because of its advantageous stability and safety. However, its short half-life and undesirable tumor targeting ability has limited its usage in tumor treatment. In this work, two types of functional peptides, half-life extension peptide PAS, and tumor targeting peptide RGDK (Arg-Gly-Asp-Lys), are inserted to human heavy-chain ferritin (HFn) at C-terminal through flexible linkers with two distinct enzyme cleavable sites. Structural characterizations show both HFn and engineered HFns can assemble into nanoparticles but with different apparent hydrodynamic volumes and molecular weights. RGDK peptide enhanced the internalization efficiency of HFn and showed a significant increase of growth inhibition against 4T1 cell line in vitro. Pharmacokinetic study in vivo demonstrates PAS peptides extended ferritin half-life about 4.9 times in Sprague Dawley rats. RGDK peptides greatly enhanced drug accumulation in the tumor site rather than in other organs in biodistribution analysis. Drug loaded PAS-RGDK functionalized HFns curbed tumor growth with significantly greater efficacies in comparison with drug loaded HFn.

Optical polarization-based seismic and water wave sensing on transoceanic cables

Seafloor geophysical instrumentation is challenging to deploy and maintain but critical for studying submarine earthquakes and Earth's interior. Emerging fiber-optic sensing technologies that can leverage submarine telecommunication cables present an opportunity to fill the data gap. We successfully sensed seismic and water waves over a 10,000-kilometer-long submarine cable connecting Los Angeles, California, and Valparaiso, Chile, by monitoring the polarization of regular optical telecommunication channels. We detected multiple moderate-to-large earthquakes along the cable in the 10-millihertz to 5-hertz band. We also recorded pressure signals from ocean swells in the primary microseism band, implying the potential for tsunami sensing. Our method, because it does not require specialized equipment, laser sources, or dedicated fibers, is highly scalable for converting global submarine cables into continuous real-time earthquake and tsunami observatories.

Remote Mesoscopic Signatures of Induced Magnetic Texture in Graphene

Mesoscopic conductance fluctuations are a ubiquitous signature of phase-coherent transport in small conductors, exhibiting universal character independent of system details. In this Letter, however, we demonstrate a pronounced breakdown of this universality, due to the interplay of local and remote phenomena in transport. Our experiments are performed in a graphene-based interaction-detection geometry, in which an artificial magnetic texture is induced in the graphene layer by covering a portion of it with a micromagnet. When probing conduction at some distance from this region, the strong influence of remote factors is manifested through the appearance of giant conductance fluctuations, with amplitude much larger than e^{2}/h. This violation of one of the fundamental tenets of mesoscopic physics dramatically demonstrates how local considerations can be overwhelmed by remote signatures in phase-coherent conductors.

MiR-125b acts as a tumor suppressor of melanoma by targeting NCAM

PURPOSE

To investigate the effects of micro ribonucleic acid (miR)-125b on the growth and apoptosis of malignant melanoma (MM) cells and related mechanisms.

METHODS

The differences in the expressions of miR-125b and neural cell adhesion molecule-120 (NCAM-120), NCAM-140 and NCAM-180 in 5 cases of MM tissues (MM group) and corresponding adjacent tissues (Paracancer group) as well as MM cells were detected via quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry, respectively. Next, malignant melanoma A375 cells were selected to exogenously overexpress miR-125 (miR-125 mimic group). Then, in vitro functional assays were conducted to determine the influences of miR-125b on the proliferation, migration and apoptosis of MM cells, and the changes in the binding of miR-125b to the 3&#39;-untranslated region (3&#39;-UTR) of wild-type and mutant NCAM messenger RNAs (mRNAs) were verified using dual-luciferase assay.

RESULTS

MiR-125b was significantly lowly expressed in MM tissues and cells (p&lt;0.01), while NCAM-120, NCAM-140 and NCAM-180 were clearly highly expressed in MM tissues and cells (p&lt;0.05). After miR-125b was exogenously overexpressed in A375 cells, the proliferation and migration ability of A375 cells was decreased, whereas the proportion of apoptotic cells rose (p&lt;0.05). Besides, the results of dual-luciferase reporter assay revealed that the luciferase activity of A375 cells in the 3&#39;-UTR of wild-type NCAM mRNA was overtly lowered compared with that of mutant NCAM mRNA (p&lt;0.05).

CONCLUSIONS

MiR-125b acts as a tumor suppressor in MM cells by targeting and binding to NCAM.

Bifunctional Carbon Dots Derived From an Anaerobic Bacterium of Porphyromonas gingivalis for Selective Detection of Fe3+ and Bioimaging

In this study, for the first time, Porphyromonas gingivalis, an anaerobic bacterium, was selected to synthesize carbon dots. The achieved P. gingivalis-carbon dots (Pg-CDs) exhibited strong fluorescence and high stability with capability for dual function as Fe³⁺ sensor and intracellular imaging agent. The detection limit for Fe³⁺ was as low as 1.85 µm. On the other hand, the prepared Pg-CDs were an excellent candidate for biosensor with high biocompatibility.

In vitro preparation of uniform and nucleic acid free hepatitis B core particles through an optimized disassembly-purification-reassembly process

Structure heterogeneity and host nucleic acids contamination are two major problems for virus-like particles (VLPs) produced by various host cells. In this study, an in vitro optimized disassembly-purification-reassembly process was developed to obtain uniform and nucleic acid free hepatitis B core (HBc) based VLPs from E. coli fermentation. The process started with ammonium sulfate precipitation of all heterogeneous HBc structures after cell disintegration. Then, dissolution and disassembly of pellets into basic subunits were carried out under the optimized disassembly condition. All contaminants, including host nucleic acids and proteins, were efficiently removed with affinity chromatography. The purified subunits reassembled into VLPs by final removal of the chaotropic agent. Two uniform and nucleic acid free HBc-based VLPs, truncated HBc₁₄₉ and chimeric HBc₁₈₃-MAGE3 I, were successfully prepared. It was found that disassembly degree of HBc-based VLPs had a great influence on the protein yield, nucleic acid removal and reassembly efficiency. 4 M urea was optimal because lower concentration would not disassemble the particles completely while higher concentration would further denature the subunits into disordered aggregate and could not be purified and reassembled efficiently. For removal of strong binding nucleic acids such as in the case of HBc₁₈₃-MAGE3 I, benzonase nuclease was added to the disassembly buffer before affinity purification. Through the optimized downstream process, uniform and nucleic acid free HBc₁₄₉ VLPs and HBc₁₈₃-MAGE3 I VLPs were obtained with purities above 90% and yields of 55.2 and 43.0 mg/L, respectively. This study would be a reference for efficient preparation of other VLPs.

Antimalarial agent artesunate induces G0/G1 cell cycle arrest and apoptosis via increasing intracellular ROS levels in normal liver cells

Artesunate (ARS) has been shown to be highly effective against chloroquine-resistant malaria. In vitro studies reported that ARS has anticancer effects; however, its detrimental action on cancer cells may also play a role in its toxicity toward normal cells and its potential toxicity has not been sufficiently researched. In this study, we investigated the possible cytotoxic effects using normal BRL-3A and AML12 liver cells. The results showed that ARS dose-dependently inhibited cell proliferation and arrested the G0/G1 phase cell cycle in both BRL-3A and AML12 liver cells. Western blotting demonstrated that ARS induced a significant downregulation of cyclin-dependent kinase-2 (CDK2), CDK4, cyclin D1, and cyclin E1 in various levels and then caused apoptosis when the Bcl-2/Bax ratio decreased. Conversely, the levels of intracellular reactive oxygen species (ROS) were increased. The ROS scavenger N-acetylcysteine can significantly inhibit cell cycle arrest and apoptosis induced by ARS. Thus, the data confirmed that ARS exposure impairs normal liver cell proliferation by inducing G0/G1 cell cycle arrest and apoptosis, and this detrimental action may be associated with intracellular ROS accumulation. Collectively, the possible side effects of ARS on healthy normal cells cannot be neglected when developing therapies.

Degradation kinetics and mechanism of 3-Chlorobenzoic acid in anoxic water environment using graphene/TiO2 as photocatalyst

Degradation kinetics and mechanism of 3-Chlorobenzoic acid (3-CBA) in anoxic water environment using graphene/TiO₂ (GR/TiO₂) as photocatalyst had been investigated. The effects of various parameters such as catalyst dosage, pH, initial concentration, catalyst reuse and dissolved oxygen (DO) on 3-CBA photocatalytic degradation kinetics were studied. The qualitative and quantitative analysis for degradation intermediate products and parent compound were studied by using HPLC, HPLC/MS/MS and IC technologies. The results show that the residual concentration of 3-CBA has a good linear relationship and its correlation coefficient R ² are all greater than 0.985 by Langmuir-Hinshelwood (L-H) dynamic model under different photocatalytic degradation conditions. Some oxidative degradation products such as 3-chlorophenol, resorcinol, and hydroxyquinol are generated, and some reductive degradation products such as 3-chlorobenzaldehyde, 3-hydroxybenzaldehyde, 3-hydroxybenzyl alcohol, and cyclohexanediol are produced, and part of 3-CBA are mineralized to generate CO₂ when DO is in the range of 0.5-1.0 mg/L; When DO is less than 0.28 mg/L, photocatalytic reduction mainly occurs. The results provide a theoretical basis for photocatalytic in situ remediation of pollutants in anoxic water environment.

0559 Association of Rapid Eye Movement Sleep with Insulin Resistance in Han Chinese Patients With Obstructive Sleep Apnea

Introduction

Obstructive sleep apnea (OSA) is increasingly associated with insulin resistance. The underlying pathophysiology remains unclear but rapid eye movement (REM) sleep has been hypothesized to play a key role. To investigate the associations of insulin resistance with respiratory events and sleep duration during REM sleep, 4,062 Han Chinese individuals with suspected OSA were screened and 2,899 were analyzed.

Methods

We screened 4,062 participants with suspected OSA who underwent polysomnography in our sleep center from 2009 to 2016. Polysomnographic variables, biochemical indicators, and physical measurements were collected. Logistic regression analyses were conducted to determine the odds ratios (ORs) and 95% confidence intervals (95% CIs) for insulin resistance as assessed by hyperinsulinemia, the homeostasis model assessment of insulin resistance (HOMA-IR), fasting insulin resistance index (FIRI), and Bennet’s insulin sensitivity index (ISI).

Results

The final analyses included 2,899 participants. After adjusting for age, gender, body mass index, waist circumference, mean arterial pressure, smoking status, alcohol consumption, and the apnea and hypopnea index during non-REM sleep (AHINREM), the results revealed that AHI during REM sleep (AHIREM) was independently associated with insulin resistance; across higher AHIREM quartiles, the ORs (95% CIs) for hyperinsulinemia were 1.340 (1.022, 1.757), 1.210 (0.882, 1.660), and 1.632 (1.103, 2.416); those for abnormal HOMA-IR were 1.287 (0.998, 1.661), 1.263 (0.933, 1.711), and 1.556 (1.056, 2.293); those for abnormal FIRI were 1.386 (1.048, 1.835), 1.317 (0.954, 1.818), and 1.888 (1.269, 2.807); and those for abnormal Bennet’s ISI were 1.297 (1.003, 1.678), 1.287 (0.949, 1.747), and 1.663 (1.127, 2.452) (P &lt; 0.01 for all linear trends). Additionally, the results showed that for every 1-h increase in REM duration, the risk of hyperinsulinemia decreased by 22.3% (P &lt; 0.05).

Conclusion

The present study demonstrated that AHIREM was independently associated with hyperinsulinemia and abnormal HOMA-IR, FIRI, and Bennet’s ISI. Additionally, REM sleep duration was independently associated with hyperinsulinemia.

Support

This study was supported by Grants-in-aid from Shanghai Municipal Commission of Science and Technology (No.18DZ2260200).

0713 Association Between Obesity Indices And Obstructive Sleep Apnea Is Modified By Age In A Sex-specific Manner

Introduction

The beneficial effects of weight loss on obstructive sleep apnea (OSA) are highly variable. Whether the variability is associated with the effects of age and sex remains unclear. This study examined this issue with large cross-sectional data.

Methods

A total of 4600 adult males and 1156 females with suspected OSA were included in the study. Anthropometric measurements, polysomnographic variables, biochemical indicators, and medical history were collected for each subject. Multivariable linear regression with interaction terms was used to estimate the modification effect of age on the associations between OSA severity (assessed by apnea-hypopnea index, AHI) with obesity indices (body mass index, BMI; neck circumference, NC; waist circumference, WC) in a sex-specific manner, and vice versa.

Results

BMI, NC, and WC were all positively correlated with AHI after adjusting for potential confounders in all populations. In males, these associations were much stronger and more significant in younger than older individuals (P for interaction &lt; 0.001). For example, a 10% increase in BMI was independently associated with a 31.6% increase in AHI for males &lt; 40 years old, whereas the corresponding increases were 20.8% and 16.7% for males 40-60 and &gt;60 years old, respectively. By contrast, no modification effect of age was observed in females (P for interaction &gt; 0.05). A 10% increase in BMI was associated with 25.6%, 26.8%, and 23.8% increases in AHI for females &lt; 40, 40-60, and &gt;60 years old, respectively.

Conclusion

Age modifies the associations between obesity indices and OSA severity in a sex-specific manner, and vice versa. These findings may broaden the understanding of age- and sex-related heterogeneities in the pathogenic role of obesity in OSA, and may be beneficial for individualized risk evaluation and treatment management for patients with OSA.

Support

This study was funded by Shanghai Municipal Commission of Science and Technology (grant number.18DZ2260200); the National Key R&D Program of China (grant number: 2017YFC0112500); Multi-Center Clinical Research Project from the School of Medicine, Shanghai Jiao Tong University (grant number: DLY201502); and the Shanghai Shen-Kang Hospital Management Center Project (grant number: SHDC12015101 and 16CR3103B).

0601 Use of The Epworth Sleepiness Scale, the NoSAS, and the STOP-BANG Questionnaire to Identify Patients with Moderate-to-Severe Obstructive Sleep Apnea

Introduction

A variety of scales and questionnaires regarding sleep and sleep-related disorders have been widely used in scientific research and clinical practice, as important tools for differential diagnosis and rapid screening of complex sleep disorders, especially obstructive sleep apnea (OSA). However, the diagnostic efficacy of different scales and questionnaires for patients with different severity of OSA and of different demographic characteristics has not been clearly described. In this study, we evaluated the ability of the most popular scales, including the Epworth Sleepiness Scale (ESS), the NoSAS, and the STOP-BANG questionnaire in predicting moderate-to-severe obstructive sleep apnea (OSA) by gender.

Methods

This cross-sectional study screened 2,031 consecutive subjects referred with suspected OSA from 2012 to 2016. Anthropometric measurements, polysomnographic data, ESS, NoSAS scores and STOP-BANG scores were recorded. Receiver operating characteristic curve analyses were performed, and the final predictive models were verified in a validation cohort.

Results

A total of 1,840 adults were finally included. The STOP-BANG questionnaire afforded a better diagnostic accuracy than did the ESS, with different cutoffs for the two genders: 3 in males and 1 in females. A predictive model based on STOP-BANG yielded an area under the curve (AUC) of 0.918 (0.897-0.935), a sensitivity of 79.89%, and a specificity of 89.19%, in males; and an AUC of 0.951 (0.914-0.975), a sensitivity of 80.52%, and a specificity of 95.92%, in females. In the validation cohort, the sensitivity and specificity were respectively 85.44 and 93.00% in males and respectively 83.02 and 87.60% in females.

Conclusion

The STOP-BANG questionnaire was moderately effective when used to screen for moderate-to-severe OSA. A STOP-BANG-based predictive model afforded excellent diagnostic efficacy, which could be applied in clinical practice. However, gender differences must be considered.

Support

This study was supported by Grants-in-aid from Shanghai Municipal Commission of Science and Technology (Grant No.18DZ2260200).

0565 Obstructive Sleep Apnea, But Not Short Sleep Duration, is Independently Associated with Insulin Resistance: A Large-Scale Cohort Study

Introduction

Both short sleep duration and obstructive sleep apnea (OSA) seem to be associated with insulin resistance. However, the majority of previous studies addressing the relationship between OSA and insulin resistance did not evaluate short sleep duration, and vice versa. In this study, we used a large-scale hospital-based cross-sectional dataset, including 5,447 participants, to examine 1) whether objectively measured short sleep duration and OSA are independently associated with insulin resistance, and 2) whether the presence of OSA modulates the association between sleep duration and insulin resistance.

Methods

Participants were consecutively enrolled from our sleep center during the period from 2007 to 2017. The index of homeostasis model assessment insulin resistance (HOMA-IR) was calculated from insulin and glucose. Sleep duration was determined by standard polysomnography. The associations between sleep duration and insulin resistance were estimated by logistic regression analyses.

Results

A total of 5,447 participants (4507 OSA and 940 primary snorers) were included in the study. In comparison to primary snorers, OSA combined with extremely short sleep duration (&lt; 5 hours) increased the risk of insulin resistance by 34% (OR, 1.34; 95% CI, 1.01-1.77) after adjusting for confounding factors that are frequently associated with insulin resistance and OSA. In subgroup analysis stratified by sleep duration, the risk of insulin resistance in patients with a short sleep duration (5-6 hours or &lt; 5 hours) was increased in those with OSA compared to primary snorers, but not in the other three sleep duration groups (6 - 7, 7 - 8, and &gt; 8 hours).

Conclusion

OSA, but not short sleep duration, was independently associated with insulin resistance. It is worth noting that OSA combined with extremely short sleep duration showed a greater detrimental effect than OSA itself with regard to insulin resistance.

Support

This study was supported by grants-in-aid from Shanghai Municipal Commission of Science and Technology (Grant No.18DZ2260200).

Universal scaling of weak localization in graphene due to bias-induced dispersion decoherence

The differential conductance of graphene is shown to exhibit a zero-bias anomaly at low temperatures, arising from a suppression of the quantum corrections due to weak localization and electron interactions. A simple rescaling of these data, free of any adjustable parameters, shows that this anomaly exhibits a universal, temperature- (T) independent form. According to this, the differential conductance is approximately constant at small voltages (V < kBT/e), while at larger voltages it increases logarithmically with the applied bias. For theoretical insight into the origins of this behaviour, which is inconsistent with electron heating, we formulate a model for weak-localization in the presence of nonequilibrium transport. According to this model, the applied voltage causes unavoidable dispersion decoherence, which arises as diffusing electron partial waves, with a spread of energies defined by the value of the applied voltage, gradually decohere with one another as they diffuse through the system. The decoherence yields a universal scaling of the conductance as a function of eV/kBT, with a logarithmic variation for eV/kBT > 1, variations in accordance with the results of experiment. Our theoretical description of nonequilibrium transport in the presence of this source of decoherence exhibits strong similarities with the results of experiment, including the aforementioned rescaling of the conductance and its logarithmic variation as a function of the applied voltage.