The PpMYB75-PpDFR module reveals the difference between 'SR' and its bud variant 'RMHC' in peach red flesh.

'Red Meat Honey Crisp (RMHC)' has been widely cultivated by growers in recent years due to its early maturity, and red meat type characteristics. As a bud variant of 'Super Red (SR)' peach, red flesh is the most distinctive characteristic of 'Red Meat Honey Crisp (RMHC)'. However, the mechanism of red flesh formation in 'RMHC' remains unclear. In this study, 79 differentially produced metabolites were identified by metabolomics analysis. The anthocyanin content in 'RMHC' was significantly higher than that in 'SR' during the same period, such as cyanidin O-syringic acid and cyanidin 3-O-glucoside. Other flavonoids also increased during the formation of red flesh, including flavonols (6-hydroxykaempferol-7-O-glucoside, hyperin), flavanols (protocatechuic acid, (+)-gallocatechin), and flavonoids (chrysoeriol 5-O-hexoside, tricetin). In addition, transcriptomic analysis and RT-qPCR showed that the expression levels of the flavonoid synthesis pathway transcription factor MYB75 and some structural genes, such as PpDFR, PpCHS, PpC4H, and PpLDOX increased significantly in 'RMHC'. Subcellular localization analysis revealed that MYB75 was localized to the nucleus. Yeast single hybridization assays showed that MYB75 bound to the cis-acting element CCGTTG of the PpDFR promoter region. The MYB75-PpDFR regulatory network was identified to be a key pathway in the reddening of 'RMHC' flesh. Moreover, this is the first study to describe the cause for red meat reddening in 'RMHC' compared to 'SR' peaches using transcriptomics, metabolomics and molecular methods. Our study identified a key transcription factor involved in the regulation of the flavonoid synthetic pathway and contributes to peach breeding-related efforts as well as the identification of genes involved in color formation in other species.

Analysis of long noncoding RNAs and messenger RNAs expression profiles in the hearts of mice with acute viral myocarditis.

Acute viral myocarditis (AVMC) is a common acute myocardial inflammation caused by viral infections, which can lead to severe cardiac dysfunction. Several long noncoding RNAs (lncRNAs) with aberrant expression have been identified in the pathogenesis of AVMC. However, the expression profiles and functions of lncRNAs in AVMC have not been fully elucidated. In the present study, we constructed AVMC mouse models by intraperitoneal injection of coxsackievirus B3 (CVB3) and performed RNA sequencing (RNA-seq) on heart tissues to investigate the differences in lncRNAs and messenger RNAs (mRNAs) expression profiles. Based on the cutoff criteria of adjusted p-values (padj) <0.05 and |log2FoldChange| >1, a total of 1122 differentially expressed lncRNAs (DElncRNAs) and 3186 differentially expressed mRNAs (DEmRNAs) were screened, including 734 upregulated and 388 downregulated lncRNAs, 1821 upregulated and 1365 downregulated mRNAs. RT-qPCR analysis validated that the expression patterns of 12 randomly selected genes (6 DElncRNAs and 6 DEmRNAs) were highly consistent with those in RNA-seq, proving the reliability of the RNA-seq data. Then, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that differentially expressed genes were mainly involved in metabolic and immune-related processes. Furthermore, co-expression networks between DElncRNAs and DEmRNAs in cytokine-cytokine receptor interaction, MAPK signaling pathway, and PI3K-Akt signaling pathway were constructed to study the molecular interactions of these molecules. Our study, for the first time, reveals the expression profiles of lncRNAs and mRNAs associated with AVMC, which may shed light on the roles of lncRNAs in disease pathogenesis and aid in discovering new therapeutic targets.

Changes in bone mineral density after bariatric surgery in patients of different ages or patients with different postoperative periods: a systematic review and meta-analysis.

To assess changes in bone mineral density (BMD) following bariatric surgery (BS) in patients with different bone sites, postoperative periods and ages. Twenty-two studies were included. Femoral neck (FN) BMD decreased after surgery (MD, - 0.05 g/cm2, CI - 0.10 to - 0.01, P = 0.03). Postoperative BMD decreased more in the FN and lumbar spine (LS) of patients older than 40 (FNBMD, - 0.07 g/cm2, CI - 0.13 to - 0.00, P = 0.04; LSBMD, - 0.03 g/cm2, CI - 0.05 to - 0.00, P = 0.02) or patients with a postoperative time of greater than 12 months (FNBMD, - 0.06 g/cm2, CI - 0.12 to - 0.01, P = 0.03; LSMD, - 0.04 g/cm2, CI - 0.09 to 0.01, P = 0.12); therefore, post-BS bone loss should be monitored among patients in these groups. Longer follow-ups are needed to determine whether BMD changes or stabilizes.

Synthesis of AAB-Stacked Single-Crystal Graphene/hBN/Graphene Trilayer van der Waals Heterostructures by In Situ CVD.

van der Waals heterostructures based on graphene and hBN layers with different stacking modes are receiving considerable attention because of their potential application in fundamental physics. However, conventional exfoliation fabrication methods and layer-by-layer transfer techniques have various limitations. The CVD synthesis of high-quality large-area graphene and hBN multilayer heterostructures is essential for the advancement of new physics. Herein, the authors propose an in situ CVD growth strategy for synthesizing wafer-scale AAB-stacked single-crystal graphene/hBN/graphene trilayer van der Waals heterostructures. Single-crystal CuNi(111) alloys are prepared on sapphire, followed by the pre-dissolution of carbon atoms. Single-crystal monolayer hBN is synthesized on a plasma-cleaned CuNi(111) surface. Then, a single-crystal monolayer graphene is epitaxially grown onto the hBN surface to form graphene/hBN bilayer heterostructures. A controlled decrease in the growth temperature allows the carbon atoms to precipitate out of the CuNi(111) alloy to form single-crystal graphene at the interface between hBN and CuNi(111), thereby producing graphene/hBN/graphene trilayer van der Waals heterostructures. The stacking modes between as-grown 2D layers are investigated through Raman spectroscopy and transmission electron microscopy. This study provides an in situ CVD approach to directly synthesize large-scale single-crystal low-dimensional van der Waals heterostructures and facilitates their application in future 2D-material-based integrated circuits.

Wafer-scale single-crystal monolayer graphene grown on sapphire substrate.

The growth of inch-scale high-quality graphene on insulating substrates is desirable for electronic and optoelectronic applications, but remains challenging due to the lack of metal catalysis. Here we demonstrate the wafer-scale synthesis of adlayer-free ultra-flat single-crystal monolayer graphene on sapphire substrates. We converted polycrystalline Cu foil placed on Al2O3(0001) into single-crystal Cu(111) film via annealing, and then achieved epitaxial growth of graphene at the interface between Cu(111) and Al2O3(0001) by multi-cycle plasma etching-assisted-chemical vapour deposition. Immersion in liquid nitrogen followed by rapid heating causes the Cu(111) film to bulge and peel off easily, while the graphene film remains on the sapphire substrate without degradation. Field-effect transistors fabricated on as-grown graphene exhibited good electronic transport properties with high carrier mobilities. This work breaks a bottleneck of synthesizing wafer-scale single-crystal monolayer graphene on insulating substrates and could contribute to next-generation graphene-based nanodevices.

Knockdown of LncRNA MALAT1 Alleviates Coxsackievirus B3-Induced Acute Viral Myocarditis in Mice via Inhibiting Th17 Cells Differentiation.

Acute viral myocarditis (AVMC), most often caused by coxsackievirus B3 (CVB3) infection, is characterized by myocardial inflammation associated with high morbidity and mortality. A pathogenic role for T helper (Th) 17 cells in AVMC is well established. Long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been shown to play a key role in various inflammatory diseases. However, the expression of MALAT1 and its impact on Th17 cells differentiation in AVMC remain unclear. In the present study, we found that MALAT1 was highly expressed in mice with AVMC, and the expression was correlated positively with cardiac pathological scores, cardiac IL-17 mRNA expression, and the percentages of splenic Th17 cells. We further demonstrated that MALAT1 knockdown could significantly alleviate the severity of disease and inhibit the differentiation of Th17 cells, accompanying the reduced mRNA expression of RORγt and productions of Th17-related pro-inflammatory cytokines in vivo. Additionally, in vitro analysis showed that MALAT1 knockdown suppressed naïve CD4+ T cells differentiation towards Th17 cells. In conclusion, our results suggest that MALAT1 knockdown alleviates CVB3-induced AVMC in mice, which may be partially attributable to the decline in Th17 cells responses. MALAT1 may serve as a novel therapeutic option in AVMC.

Higher Teicoplanin Blood Level Needed in Elderly Critically Ill Patients.

BACKGROUND: Significant changes in the pathophysiology of older critically ill patients may affect the pharmacokinetics and pharmacodynamics of teicoplanin. This study aimed to determine the optimal teicoplanin blood level in this patient population. METHODS: 128 older critically ill and 86 older non-critically ill patients were involved and analyzed. RESULTS: The target thresholds of teicoplanin blood concentrations in older critically ill patients and non-critically ill patients should be 31.4mg/L and 15.3mg/L, respectively. The dose of teicoplanin in older critically ill patients should be greater than 800 mg to achieve the target blood level. CONCLUSION: An individualized dosing approach of teicoplanin based on therapeutic drug monitoring is necessary for older critically ill patients.

Neutralization of interleukin-38 exacerbates coxsackievirus B3-induced acute myocarditis in mice.

BACKGROUND: Interleukin (IL)-38, a novel member of the IL-1 family, has been reported to be involved in several diseases associated with viral infection. However, the expression and functional role of IL-38 in acute viral myocarditis (AVMC) have not been investigated. METHODS: Male BALB/c mice were treated with intraperitoneal (i.p.) injection of coxsackievirus B3 (CVB3) for establishing AVMC models. On day 7 post-injection, the expression of IL-38 and IL-36R (IL-36 receptor) were measured. Mice were then treated with i.p. injection of mouse Anti-IL-38 Antibodies (Abs) for neutralization of IL-38. The survival, bodyweight loss, cardiac function, and myocarditis severity of mice were recorded. The percentages of splenic Th1 and Th17 cells, the expression levels of Th1/Th17-related master transcription factors (T-bet and RORγt) and cytokines were determined by flow cytometry, RT-qPCR, and ELISA, respectively. Cardiac viral replication was further detected. RESULTS: The mRNA and protein expression levels of IL-38 in myocardium and serum, as well as cardiac IL-36R mRNA levels were significantly elevated in mice with AVMC. Increased IL-38 levels were negatively correlated with the severity of AVMC. Neutralization of IL-38 exacerbated CVB3-induced AVMC, as verified by the lower survival rate, impaired cardiac function, continuous bodyweight loss, and higher values of HW/BW and cardiac pathological scores. In addition, neutralization of IL-38 suppressed Th1 cells differentiation while promoted Th17 cells differentiation, accompanied by decreased T-bet mRNA expression and increased RORγt expression. Down-regulation of IFN-γ and up-regulation of IL-17, TNF-α, and IL-6 mRNA and protein expression levels in myocardium and serum were also observed in the IL-38 neutralization group. Furthermore, neutralization of IL-38 markedly promoted cardiac viral replication. CONCLUSIONS: Neutralization of IL-38 exacerbates CVB3-induced AVMC in mice, which may be attributable to the imbalance of Th1/Th17 cells and increased CVB3 replication. Thus, IL-38 can be considered as a potential therapeutic target for AVMC.

Descriptor selection for predicting interfacial thermal resistance by machine learning methods.

Interfacial thermal resistance (ITR) is a critical property for the performance of nanostructured devices where phonon mean free paths are larger than the characteristic length scales. The affordable, accurate and reliable prediction of ITR is essential for material selection in thermal management. In this work, the state-of-the-art machine learning methods were employed to realize this. Descriptor selection was conducted to build robust models and provide guidelines on determining the most important characteristics for targets. Firstly, decision tree (DT) was adopted to calculate the descriptor importances. And descriptor subsets with topX highest importances were chosen (topX-DT, X = 20, 15, 10, 5) to build models. To verify the transferability of the descriptors picked by decision tree, models based on kernel ridge regression, Gaussian process regression and K-nearest neighbors were also evaluated. Afterwards, univariate selection (UV) was utilized to sort descriptors. Finally, the top5 common descriptors selected by DT and UV were used to build concise models. The performance of these refined models is comparable to models using all descriptors, which indicates the high accuracy and reliability of these selection methods. Our strategy results in concise machine learning models for a fast prediction of ITR for thermal management applications.

Antimicrobial Mechanisms and Effectiveness of Graphene and Graphene-Functionalized Biomaterials. A Scope Review.

Bacterial infections represent nowadays the major reason of biomaterials implant failure, however, most of the available implantable materials do not hold antimicrobial properties, thus requiring antibiotic therapy once the infection occurs. The fast raising of antibiotic-resistant pathogens is making this approach as not more effective, leading to the only solution of device removal and causing devastating consequences for patients. Accordingly, there is a large research about alternative strategies based on the employment of materials holding intrinsic antibacterial properties in order to prevent infections. Between these new strategies, new technologies involving the use of carbon-based materials such as carbon nanotubes, fullerene, graphene and diamond-like carbon shown very promising results. In particular, graphene- and graphene-derived materials (GMs) demonstrated a broad range antibacterial activity toward bacteria, fungi and viruses. These antibacterial activities are attributed mainly to the direct physicochemical interaction between GMs and bacteria that cause a deadly deterioration of cellular components, principally proteins, lipids, and nucleic acids. In fact, GMs hold a high affinity to the membrane proteoglycans where they accumulate leading to membrane damages; similarly, after internalization they can interact with bacteria RNA/DNA hydrogen groups interrupting the replicative stage. Moreover, GMs can indirectly determine bacterial death by activating the inflammatory cascade due to active species generation after entering in the physiological environment. On the opposite, despite these bacteria-targeted activities, GMs have been successfully employed as pro-regenerative materials to favor tissue healing for different tissue engineering purposes. Taken into account these GMs biological properties, this review aims at explaining the antibacterial mechanisms underlying graphene as a promising material applicable in biomedical devices.

[A clinical study of the evaluation of hemodynamic status in mechanically ventilated critically ill patients by continuous non-invasive arterial pressure monitor].

OBJECTIVE: To evaluate the difference and correlation between continuous non-invasive arterial pressure (CNAP) monitor and pulse indicated continuous cardiac output (PiCCO) monitor on determination of hemodynamic parameters in mechanically ventilated critically ill patients, and to assess the feasibility of non-invasive monitoring of hemodynamics with CNAP. METHODS: A prospective observation self-control study was conducted.The critically ill patients with mechanical ventilation who needed hemodynamics monitoring, and admitted to the fourth department of intensive care unit (ICU) of Fujian Provincial Hospital from June 2018 to March 2019 were enrolled. PiCCO catheter were inserted immediately after admission, the hemodynamic indexes were measured by thermodilution method, and mean arterial pressure (MAPPiCCO), cardiac index (CIPiCCO), pulse pressure variation rate (PPVPiCCO) and systemic vascular resistance index (SVRIPiCCO) were obtained at 0 hour and 24 hours respectively. Meanwhile, the above indexes (MAPCNAP, CICNAP, PPVCNAP and SVRICNAP) were measured with CNAP. All measurements were repeated thrice and average values were reported. The differences in above parameters between the two methods were evaluated. Pearson test was used for the correlation analysis and Bland-Altman analysis method was used for consistency test. RESULTS: Thirty-eight patients were enrolled into this study. One patient died within 24 hours was excluded, 2 patients were excluded due to withdrawing treatment within 24 hours, 2 patients were excluded because of atrial fibrillation, and 1 patient's data was lost due to technical problems. Thus, data from 32 patients were available for final analysis. There were 12 females and 20 males, aging 26-84 years old with the mean of (66.8±19.1) years old, body mass index (BMI) of (23.7±3.9) kg/m2, acute physiology and chronic health evaluation II (APACHE II) score of 19.5±5.3, sepsis-related organ failure assessment (SOFA) score of 9.7±4.1. There were no significant differences in CI or PPV between CNAP and PiCCO groups [CI (mL×s-1×m-2): 59.8±12.6 vs. 58.5±14.2, PPV: (14.7±6.8)% vs. (14.0±6.8)%, both P > 0.05]. MAP and SVRI measured by CNAP were significantly higher than those measured by PiCCO [MAP (mmHg, 1 mmHg = 0.133 kPa): 65.6±9.4 vs. 60.1±9.2, SVRI (kPa×s×L-1×m-2): 206.2±53.9 vs. 179.5±57.8, both P < 0.01]. The correlation analysis showed that MAP, CI, PPV and SVRI measured by the two methods were significantly positively correlated (r value was 0.624, 0.864, 0.835 and 0.655 respectively, all P < 0.05). Bland-Altman analysis showed that CNAP and PiCCO had a good consistency for the measurement of CI and PPV, the average differences were 1.2 mL×s-1×m-2 and 0.5% respectively, while the 95% confidence interval (95%CI) were -12.8-15.3 mL×s-1×m-2 and -7.1%-8.2% respectively. However, the consistency of MAP and SVRI measured by those two methods was poor, the average differences were 5.5 mmHg and 26.8 kPa×s×L-1×m-2 respectively, while the 95%CI was -10.4-21.3 mmHg and -64.5-118.0 kPa×s×L-1×m-2 respectively. CONCLUSIONS: CNAP was comparable with PiCCO when monitoring CI and PPV in mechanically ventilated critically ill patients; while the results of MAP and SVRI might be inaccurate, which should be interpreted correctly and carefully.

High-throughput Production of ZnO-MoS2-Graphene Heterostructures for Highly Efficient Photocatalytic Hydrogen Evolution.

High-throughput production of highly efficient photocatalysts for hydrogen evolution remains a considerable challenge for materials scientists. Here, we produced extremely uniform high-quality graphene and molybdenum disulfide (MoS2) nanoplatelets through the electrochemical-assisted liquid-phase exfoliation, out of which we subsequently fabricated MoS2/graphene van der Waals heterostructures. Ultimately, zinc oxide (ZnO) nanoparticles were deposited into these two-dimensional heterostructures to produce an artificial ZnO/MoS2/graphene nanocomposite. This new composite experimentally exhibited an excellent photocatalytic efficiency in hydrogen evolution under the sunlight illumination ( λ > 400   n m ), owing to the extremely high electron mobilities in graphene nanoplatelets and the significant visible-light absorptions of MoS2. Moreover, due to the synergistic effects in MoS2 and graphene, the lifetime of excited carriers increased dramatically, which considerably improved the photocatalytic efficiency of the ZnO/MoS2/graphene heterostructure. We conclude that the novel artificial heterostructure presented here shows great potential for the high-efficient photocatalytic hydrogen generation and the high throughput production of visible-light photocatalysts for industrial applications.

Fractal-Theory-Based Control of the Shape and Quality of CVD-Grown 2D Materials.

The precise control of the shape and quality of 2D materials during chemical vapor deposition (CVD) processes remains a challenging task, due to a lack of understanding of their underlying growth mechanisms. The existence of a fractal-growth-based mechanism in the CVD synthesis of several 2D materials is revealed, to which a modified traditional fractal theory is applied in order to build a 2D diffusion-limited aggregation (2D-DLA) model based on an atomic-scale growth mechanism. The strength of this model is validated by the perfect correlation between theoretically simulated data, predicted by 2D-DLA, and experimental results obtained from the CVD synthesis of graphene, hexagonal boron nitride, and transition metal dichalcogenides. By applying the 2D-DLA model, it is also discovered that the single-domain net growth rate (SD-NGR) plays a crucial factor in governing the shape and quality of 2D-material crystals. By carefully tuning SD-NGR, various fractal-morphology high-quality single-crystal 2D materials are synthesized, achieving, for the first time, the precise control of 2D-material CVD growth. This work lays the theoretical foundation for the precise adjustment of the morphologies and physical properties of 2D materials, which is essential to the use of fractal-shaped nanomaterials for the fabrication of new-generation neural-network nanodevices.

Covalent Atomic Bridges Enable Unidirectional Enhancement of Electronic Transport in Aligned Carbon Nanotubes.

Interconnecting the surfaces of nanomaterials without compromising their outstanding mechanical, thermal, and electronic properties is critical in the design of advanced bulk structures that still preserve the novel properties of their nanoscale constituents. As such, bridging the π-conjugated carbon surfaces of single-walled carbon nanotubes (SWNTs) has special implications in next-generation electronics. This study presents a rational path toward the improvement of the electrical transport in aligned semiconducting SWNT films by deposition of metal atoms. The formation of conducting Cr-mediated pathways between the parallel SWNTs increases the transverse (intertube) conductance while having a negligible effect on the parallel (intratube) transport. In contrast, doping with Li has a predominant effect on the intratube electrical transport of aligned SWNT films. Large-scale first-principles calculations of electrical transport on aligned SWNTs show good agreement with the experimental electrical measurements and provide insight into the changes that different metal atoms exert on the density of states near the Fermi level of the SWNTs and the formation of transport channels.

Facile and environmentally friendly synthesis of six heterometallic dumbbell-shaped MLn (M = Co, Ni; Ln = Eu, Gd, Dy) clusters as cryogenic magnetic coolants and molecular magnets.

Six analogous dumbbell-shaped 3d-4f complexes MLn were obtained by the reaction of Ln(NO3)3 (Ln = Eu, Gd, Dy) and M(OAc)2 (M = Co, Ni) without any other organic ligands, and M5Gd4 exhibited a large magnetocaloric effect (-ΔSm = 31.0, 37.3 J kg-1 K-1 for Co5Gd4 and Ni5Gd4 respectively), while M5Dy4 and Co5Eu4 showed single molecule magnet behaviour. To the best of our knowledge, Co5Eu4 is the first Eu-based cluster to display single molecule magnet behaviour (Ueff = 16.4 K).

Efficient Bacterial Inactivation by Transition Metal Catalyzed Auto-Oxidation of Sulfite.

Disinfection is an indispensable process in wastewater treatment plants. New bacterial inactivation technologies are of increasing interest and persistent demand. A category of simple and efficient bactericidal systems have been established in this study, that is, the combination of divalent transition metal (Mn(II), Co(II), Fe(II), or Cu(II)) and sulfite. In these systems, metal catalyzed auto-oxidation of sulfite was manifested to generate reactive intermediary SO4•- that played the major role in Escherichia coli inactivation at pH 5-8.5. Increasing concentrations of metal ion or sulfite, and lower pH, led to higher bacterial deaths. Bacterial inactivation by Me(II)/sulfite systems was demonstrated to be a surface-bound oxidative damage process through destructing vital cellular components, such as NADH and proteins. Additionally, the developed Me(II)/sulfite systems also potently killed other microbial pathogens, that is, Pseudomonas aeruginosa, Bacillus subtilis, and Cu(II)-antibiotic-resistant E. coli. The efficacy of Me(II)/sulfite in treating real water samples was further tested with two sewages from a wastewater treatment plant and a natural lake water body, and Cu(II)/sulfite and Co(II)/sulfite rapidly inactivated viable bacteria regardless of bacteria species and cell density, therefore holding great promises for wastewater disinfection.

Visible-Blind UV Photodetector Based on Single-Walled Carbon Nanotube Thin Film/ZnO Vertical Heterostructures.

Ultraviolet (UV) photodetectors based on heterojunctions of conventional (Ge, Si, and GaAs) and wide bandgap semiconductors have been recently demonstrated, but achieving high UV sensitivity and visible-blind photodetection still remains a challenge. Here, we utilized a semitransparent film of p-type semiconducting single-walled carbon nanotubes (SC-SWNTs) with an energy gap of 0.68 ± 0.07 eV in combination with a molecular beam epitaxy grown n-ZnO layer to build a vertical p-SC-SWNT/n-ZnO heterojunction-based UV photodetector. The resulting device shows a current rectification ratio of 103, a current photoresponsivity up to 400 A/W in the UV spectral range from 370 to 230 nm, and a low dark current. The detector is practically visible-blind with the UV-to-visible photoresponsivity ratio of 105 due to extremely short photocarrier lifetimes in the one-dimensional SWNTs because of strong electron-phonon interactions leading to exciton formation. In this vertical configuration, UV radiation penetrates the top semitransparent SC-SWNT layer with low losses (10-20%) and excites photocarriers within the n-ZnO layer in close proximity to the p-SC-SWNT/n-ZnO interface, where electron-hole pairs are efficiently separated by a high built-in electric field associated with the heterojunction.

Sublimation-assisted graphene transfer technique based on small polyaromatic hydrocarbons.

Advances in the chemical vapor deposition (CVD) growth of graphene have made this material a very attractive candidate for a number of applications including transparent conductors, electronics, optoeletronics, biomedical devices and energy storage. The CVD method requires transfer of graphene on a desired substrate and this is most commonly accomplished with polymers. The removal of polymer carriers is achieved with organic solvents or thermal treatment which makes this approach inappropriate for application to plastic thin films such as polyethylene terephthalate substrates. An ultraclean graphene transfer method under mild conditions is highly desired. In this article, we report a naphthalene-assisted graphene transfer technique which provides a reliable route to residue-free transfer of graphene to both hard and flexible substrates. The quality of the transferred graphene was characterized with atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. Field effect transistors, based on the naphthalene-transfered graphene, were fabricated and characterized. This work has the potential to broaden the applications of CVD graphene in fields where ultraclean graphene and mild graphene transfer conditions are required.

Fast Electrochromic Device Based on Single-Walled Carbon Nanotube Thin Films.

Optical properties of electrochromic materials can be controlled by the application of an electric field allowing recent development of new applications such as smart windows technology for indoor climate control and energy conservation. We report the fabrication of a single-walled nanotube (SWNT) thin film based electro-optical modulator controlled by ionic liquid polarization in which the active electrochromic layer is made of a film of semiconducting (SC-) SWNTs and the counter-electrode is composed of a film of metallic (MT-) SWNTs. Optimization of this electro-optical cell allows the operations with an optical modulation depth of 3.7 dB and a response time in the millisecond range, which is thousands of times faster than typical electrolyte-controlled devices. In addition, a dual electro-optical device was built utilizing electro-optically active SC-SWNT films for each electrode that allowed increasing modulation depth of 6.7 dB while preserving the speed of the response.

Giant Raman Response to the Encapsulation of Sulfur in Narrow Diameter Single-Walled Carbon Nanotubes.

Encapsulation of sulfur in HiPCO-SWNTs leads to large changes in the Raman spectra with the appearance of new peaks at 319, 395, and 715 cm(-1) which originate from the sulfur species within the SWNTs, while the high frequency SWNT bands (ν > 1200 cm(-1)) are decreased in intensity. The encapsulated species also shifts the near-IR interband electronic transitions to lower energy by more than 10%. These effects seem to originate with the van der Waals interaction of the confined sulfur species with the walls of the SWNTs which are not expected to be significant in the case of the previously studied large diameter SWNTs. We suggest that sulfur in the small diameter SWNTs exists as a helical polymeric sulfur chain that enters the SWNT interior in the form of S2 ((3)Σ(g)(-)) molecules which undergo polymerization to linear diradicals.