Single-crystal, large-area, fold-free monolayer graphene.

Chemical vapour deposition of carbon-containing precursors on metal substrates is currently the most promising route for the scalable synthesis of large-area, high-quality graphene films1. However, there are usually some imperfections present in the resulting films: grain boundaries, regions with additional layers (adlayers), and wrinkles or folds, all of which can degrade the performance of graphene in various applications2-7. There have been numerous studies on ways to eliminate grain boundaries8,9 and adlayers10-12, but graphene folds have been less investigated. Here we explore the wrinkling/folding process for graphene films grown from an ethylene precursor on single-crystal Cu-Ni(111) foils. We identify a critical growth temperature (1,030 kelvin) above which folds will naturally form during the subsequent cooling process. Specifically, the compressive stress that builds up owing to thermal contraction during cooling is released by the abrupt onset of step bunching in the foil at about 1,030 kelvin, triggering the formation of graphene folds perpendicular to the step edge direction. By restricting the initial growth temperature to between 1,000 kelvin and 1,030 kelvin, we can produce large areas of single-crystal monolayer graphene films that are high-quality and fold-free. The resulting films show highly uniform transport properties: field-effect transistors prepared from these films exhibit average room-temperature carrier mobilities of around (7.0 ± 1.0) × 103 centimetres squared per volt per second for both holes and electrons. The process is also scalable, permitting simultaneous growth of graphene of the same quality on multiple foils stacked in parallel. After electrochemical transfer of the graphene films from the foils, the foils themselves can be reused essentially indefinitely for further graphene growth.

Biomechanical comparison of the angle of inserted screws and the length of anterior cervical plate systems with allograft spacers.

BACKGROUND: Comparative studies of the biomechanical effects of plates of varying lengths and different screw insertion angles on allograft spacers are lacking. METHODS: Finite element model analysis of a previously validated, three-dimensional, intact cervical spinal segment model of C3-6 was conducted in the present study. On the C5-6 segment, anterior discectomy and fusion were performed using allograft spacers and different combinations of anterior plates and screws. The biomechanical characteristics of combinations of short, medium, and maximal length plates with screw insertion angles of 0°, 8°, 16°, and 32° were analyzed. FINDINGS: In flexion and extension, the risk of allograft spacer subsidence decreased as screw angles increased. Short plates with a screw insertion angle of 32° posed the lowest subsidence risk, similar to medium length plates with a screw insertion angle of 16°, in all motion conditions. The risk of bone yielding increased as plate length increased, but decreased as the screw insertion angle increased. INTERPRETATION: Short plates with a large screw insertion angle (32°) showed the highest mechanical stability and load sharing of allograft spacers and the lowest risk of screw loosening. Accordingly, we recommend the use of a short plate and large screw insertion angle for anterior cervical discectomy and fusion.

Earthquake Detection in a Static and Dynamic Environment Using Supervised Machine Learning and a Novel Feature Extraction Method.

Detecting earthquakes using smartphones or IoT devices in real-time is an arduous and challenging task, not only because it is constrained with the hard real-time issue but also due to the similarity of earthquake signals and the non-earthquake signals (i.e., noise or other activities). Moreover, the variety of human activities also makes it more difficult when a smartphone is used as an earthquake detecting sensor. To that end, in this article, we leverage a machine learning technique with earthquake features rather than traditional seismic methods. First, we split the detection task into two categories including static environment and dynamic environment. Then, we experimentally evaluate different features and propose the most appropriate machine learning model and features for the static environment to tackle the issue of noisy components and detect earthquakes in real-time with less false alarm rates. The experimental result of the proposed model shows promising results not only on the given dataset but also on the unseen data pointing to the generalization characteristics of the model. Finally, we demonstrate that the proposed model can be also used in the dynamic environment if it is trained with different dataset.

Large-area single-crystal AB-bilayer and ABA-trilayer graphene grown on a Cu/Ni(111) foil.

High-quality AB-stacked bilayer or multilayer graphene larger than a centimetre has not been reported. Here, we report the fabrication and use of single-crystal Cu/Ni(111) alloy foils with controllable concentrations of Ni for the growth of large-area, high-quality AB-stacked bilayer and ABA-stacked trilayer graphene films by chemical vapour deposition. The stacking order, coverage and uniformity of the graphene films were evaluated by Raman spectroscopy and transmission electron microscopy including selected area electron diffraction and atomic resolution imaging. Electrical transport (carrier mobility and band-gap tunability) and thermal conductivity (the bilayer graphene has a thermal conductivity value of about 2,300 W m-1 K-1) measurements indicated the superior quality of the films. The tensile loading response of centimetre-scale bilayer graphene films supported by a 260-nm thick polycarbonate film was measured and the average values of the Young's modulus (478 GPa) and fracture strength (3.31 GPa) were obtained.

Chemically induced transformation of chemical vapour deposition grown bilayer graphene into fluorinated single-layer diamond.

Notwithstanding the numerous density functional studies on the chemically induced transformation of multilayer graphene into a diamond-like film carried out to date, a comprehensive convincing experimental proof of such a conversion is still lacking. We show that the fluorination of graphene sheets in Bernal (AB)-stacked bilayer graphene grown by chemical vapour deposition on a single-crystal CuNi(111) surface triggers the formation of interlayer carbon-carbon bonds, resulting in a fluorinated diamond monolayer ('F-diamane'). Induced by fluorine chemisorption, the phase transition from (AB)-stacked bilayer graphene to single-layer diamond was studied and verified by X-ray photoelectron, UV photoelectron, Raman, UV-Vis and electron energy loss spectroscopies, transmission electron microscopy and density functional theory calculations.

Adlayer-Free Large-Area Single Crystal Graphene Grown on a Cu(111) Foil.

To date, thousands of publications have reported chemical vapor deposition growth of "single layer" graphene, but none of them has described truly single layer graphene over large area because a fraction of the area has adlayers. It is found that the amount of subsurface carbon (leading to additional nuclei) in Cu foils directly correlates with the extent of adlayer growth. Annealing in hydrogen gas atmosphere depletes the subsurface carbon in the Cu foil. Adlayer-free single crystal and polycrystalline single layer graphene films are grown on Cu(111) and polycrystalline Cu foils containing no subsurface carbon, respectively. This single crystal graphene contains parallel, centimeter-long ≈100 nm wide "folds," separated by 20 to 50 µm, while folds (and wrinkles) are distributed quasi-randomly in the polycrystalline graphene film. High-performance field-effect transistors are readily fabricated in the large regions between adjacent parallel folds in the adlayer-free single crystal graphene film.

Ultrastiff, Strong, and Highly Thermally Conductive Crystalline Graphitic Films with Mixed Stacking Order.

A macroscopic film (2.5 cm × 2.5 cm) made by layer-by-layer assembly of 100 single-layer polycrystalline graphene films is reported. The graphene layers are transferred and stacked one by one using a wet process that leads to layer defects and interstitial contamination. Heat-treatment of the sample up to 2800 °C results in the removal of interstitial contaminants and the healing of graphene layer defects. The resulting stacked graphene sample is a freestanding film with near-perfect in-plane crystallinity but a mixed stacking order through the thickness, which separates it from all existing carbon materials. Macroscale tensile tests yields maximum values of 62 GPa for the Young's modulus and 0.70 GPa for the fracture strength, significantly higher than has been reported for any other macroscale carbon films; microscale tensile tests yield maximum values of 290 GPa for the Young's modulus and 5.8 GPa for the fracture strength. The measured in-plane thermal conductivity is exceptionally high, 2292 ± 159 W m-1 K-1 while in-plane electrical conductivity is 2.2 × 105 S m-1 . The high performance of these films is attributed to the combination of the high in-plane crystalline order and unique stacking configuration through the thickness.

Colossal grain growth yields single-crystal metal foils by contact-free annealing.

Single-crystal metals have distinctive properties owing to the absence of grain boundaries and strong anisotropy. Commercial single-crystal metals are usually synthesized by bulk crystal growth or by deposition of thin films onto substrates, and they are expensive and small. We prepared extremely large single-crystal metal foils by "contact-free annealing" from commercial polycrystalline foils. The colossal grain growth (up to 32 square centimeters) is achieved by minimizing contact stresses, resulting in a preferred in-plane and out-of-plane crystal orientation, and is driven by surface energy minimization during the rotation of the crystal lattice followed by "consumption" of neighboring grains. Industrial-scale production of single-crystal metal foils is possible as a result of this discovery.

Camphor-Enabled Transfer and Mechanical Testing of Centimeter-Scale Ultrathin Films.

Camphor is used to transfer centimeter-scale ultrathin films onto custom-designed substrates for mechanical (tensile) testing. Compared to traditional transfer methods using dissolving/peeling to remove the support-layers, camphor is sublimed away in air at low temperature, thereby avoiding additional stress on the as-transferred films. Large-area ultrathin films can be transferred onto hollow substrates without damage by this method. Tensile measurements are made on centimeter-scale 300 nm-thick graphene oxide film specimens, much thinner than the ≈2 µm minimum thickness of macroscale graphene-oxide films previously reported. Tensile tests were also done on two different types of large-area samples of adlayer free CVD-grown single-layer graphene supported by a ≈100 nm thick polycarbonate film; graphene stiffens this sample significantly, thus the intrinsic mechanical response of the graphene can be extracted. This is the first tensile measurement of centimeter-scale monolayer graphene films. The Young's modulus of polycrystalline graphene ranges from 637 to 793 GPa, while for near single-crystal graphene, it ranges from 728 to 908 GPa (folds parallel to the tensile loading direction) and from 683 to 775 GPa (folds orthogonal to the tensile loading direction), demonstrating the mechanical performance of large-area graphene in a size scale relevant to many applications.

Brain stimulation patterns emulating endogenous thalamocortical input to parvalbumin-expressing interneurons reduce nociception in mice.

BACKGROUND: The bursting pattern of thalamocortical (TC) pathway dampens nociception. Whether brain stimulation mimicking endogenous patterns can engage similar sensory gating processes in the cortex and reduce nociceptive behaviors remains uninvestigated. OBJECTIVE: We investigated the role of cortical parvalbumin expressing (PV) interneurons within the TC circuit in gating nociception and their selective response to TC burst patterns. We then tested if transcranial magnetic stimulation (TMS) patterned on endogenous nociceptive TC bursting modulate nociceptive behaviors. METHODS: The switching of TC neurons between tonic (single spike) and burst (high frequency spikes) firing modes may be a critical component in modulating nociceptive signals. Deep brain electrical stimulation of TC neurons and immunohistochemistry were used to examine the differential influence of each firing mode on cortical PV interneuron activity. Optogenetic stimulation of cortical PV interneurons assessed a direct role in nociceptive modulation. A new TMS protocol mimicking thalamic burst firing patterns, contrasted with conventional continuous and intermittent theta burst protocols, tested if TMS patterned on endogenous TC activity reduces nociceptive behaviors in mice. RESULTS: Immunohistochemical evidence confirmed that burst, but not tonic, deep brain stimulation of TC neurons increased the activity of PV interneurons in the cortex. Both optogenetic activation of PV interneurons and TMS protocol mimicking thalamic burst reduced nociceptive behaviors. CONCLUSIONS: Our findings suggest that burst firing of TC neurons recruits PV interneurons in the cortex to reduce nociceptive behaviors and that neuromodulation mimicking thalamic burst firing may be useful for modulating nociception.

Correction to: Achilles tenodesis for calcaneal insufficiency avulsion fractures associated with diabetes mellitus.

The original publication of this article [1] contained the wrong versions of tables 1, 2 and 3. In this correction the updated tables are published. The original publication has been updated.

Achilles tenodesis for calcaneal insufficiency avulsion fractures associated with diabetes mellitus.

BACKGROUND: Calcaneal insufficiency avulsion (CIA) fractures often present with neuropathic etiology, such as Charcot neuroarthropathy (CN). Under the same surgical procedures, the outcomes of CIA fractures are less desirable, compared to the outcomes of the traumatic calcaneal avulsion fractures. Here, the study suggests Achilles tenodesis technique using suture anchor after resection of the CIA fracture fragments could provide satisfactory clinical results in the cases of surgically indicated CIA fractures. MATERIALS AND METHODS: This retrospective study included seven patients of calcaneal avulsion fracture who had underlying diabetes mellitus (DM) and no specific traumatic event. The patients were treated with Achilles tenodesis techniques for their CIA fractures. Achilles tenodesis was performed using suture anchor with removal of the fracture fragments. The patients were evaluated with the Foot and Ankle Outcome Score (FAOS), visual analogue scale (VAS), single-heel rise test, and X-ray images on their final follow-ups. RESULTS: Initially, three of the CIA fracture cases treated with traditional open reduction and internal fixation reported pullout failure. Consequently, all patients received Achilles tenodesis using suture anchor after bone fragment resection and had good clinical outcomes. Only one subject with low compliance reported poor outcome. The FAOS of each patient were obtained at a mean of 16.3 months after surgery. The results are as follows: pain 80.6 (SD = 6.2), symptom 83.8 (SD = 4.9), activities of daily living 80.5 (SD = 8.0), sport and recreation function 75.6 (SD = 11.93), and foot- and ankle-related quality of life 77.9 (SD = 6.7). On their final follow-ups, the average VAS was 2.6 (range, 1 to 4). CONCLUSION: Achilles tenodesis using suture anchor after bone fragment resection achieved competent clinical results in the patients with CIA fractures. The study proposes that this surgical procedure could be an appropriate treatment option for patients with CIA fractures. TRIAL REGISTRATION: The study was approved by the institutional review board (IRB) of our medical center (IRB File No. 2016-07-043), retrospectively registered.

MyShake: A smartphone seismic network for earthquake early warning and beyond.

Large magnitude earthquakes in urban environments continue to kill and injure tens to hundreds of thousands of people, inflicting lasting societal and economic disasters. Earthquake early warning (EEW) provides seconds to minutes of warning, allowing people to move to safe zones and automated slowdown and shutdown of transit and other machinery. The handful of EEW systems operating around the world use traditional seismic and geodetic networks that exist only in a few nations. Smartphones are much more prevalent than traditional networks and contain accelerometers that can also be used to detect earthquakes. We report on the development of a new type of seismic system, MyShake, that harnesses personal/private smartphone sensors to collect data and analyze earthquakes. We show that smartphones can record magnitude 5 earthquakes at distances of 10 km or less and develop an on-phone detection capability to separate earthquakes from other everyday shakes. Our proof-of-concept system then collects earthquake data at a central site where a network detection algorithm confirms that an earthquake is under way and estimates the location and magnitude in real time. This information can then be used to issue an alert of forthcoming ground shaking. MyShake could be used to enhance EEW in regions with traditional networks and could provide the only EEW capability in regions without. In addition, the seismic waveforms recorded could be used to deliver rapid microseism maps, study impacts on buildings, and possibly image shallow earth structure and earthquake rupture kinematics.

Complete Genome Sequence of Type 1 Porcine Reproductive and Respiratory Syndrome Virus Strain E38, Isolated from South Korea with a Novel Deletion.

We report the complete genome sequence of the European type 1 porcine reproductive and respiratory syndrome virus E38 strain, isolated from South Korea with a novel deletion. It contains a 61-nucleotide discontinuous deletion of the Nsp2 and Nsp12 regions. This study will aid in understanding the genetic diversity of type 1 PRRSV and in manufacturing a construct based on Korean vaccine candidate development.

A new antenna system for microwave non-invasive hyperthermia lipolysis.

In this paper, we present an antenna system for microwave non-invasive hyperthermia lipolysis. The antenna system consists of a circular waveguide antenna radiating electromagnetic waves, AlN (Aluminum Nitride) radome and heat sink. The AlN radome with heat sink helps to extract heat from the skin to keep skin temperature not to rise during heating the lipolysis. The antenna was designed to be operated with TE(21) mode to maintain uniform temperature over wider area. The usability of the proposed system was verified by performing numerical simulation and hyperthermia lipolysis experiments on rats.

High-frequency microwave ablation method for enhanced cancer treatment with minimized collateral damage.

To overcome the limits of conventional microwave ablation, a new frequency spectrum above 6 GHz has been explored for low-power and low collateral damage ablation procedure. A planar coaxial probe-based applicator, suitable for easy insertion into the human body, was developed for our study to cover a wideband frequency up to 30 GHz. Thermal ablations with small input power (1-3 W) at various microwave frequencies were performed on nude mice xenografted with human breast cancer. Comparative study of ablation efficiencies revealed that 18-GHz microwave results in the largest difference in the temperature rise between cancer and normal tissues as well as the highest ablation efficiency, reaching 20 times that of 2 GHz. Thermal profile study on the composite region of cancer and fat also showed significantly reduced collateral damage using 18 GHz. Application of low-power (1 W) 18-GHz microwave on the nude mice xenografted with human breast cancer cells resulted in recurrence-free treatment. The proposed microwave ablation method can be a very effective process to treat small-sized tumor with minimized invasiveness and collateral damages.

Web-based comprehensive information system for self-management of diabetes mellitus.

BACKGROUND: The aim of this study is to evaluate the effect of a web-based comprehensive information system, consisting of Internet and cellular phone use, on blood glucose control. METHODS: We established eMOD (electronic Management of Diabetes), a web-based ubiquitous information system, for cell phone users along with a website for Internet users to provide diabetes education. We examined whether this information system has the same impact on glycemic control as conventional education for the diabetes patient. Forty volunteers were enrolled and randomly assigned to either the eMOD experimental group (n = 20) or the control group (n = 20). Blood glucose and glycated hemoglobin (A1C) levels were evaluated at baseline and after 6 months. RESULTS: The two groups were homogeneous in terms of age, sex, and diabetes' duration at baseline. A1C (from 9.0 +/- 2.3% to 7.5 +/- 1.4%, P = 0.031) and postprandial glucose level (228.1 +/- 79.7 to 173.5 +/- 50.2 mg/dL, P = 0.030) were significantly decreased over time in the intervention group but not in the control group. There was a significant relationship between the change in A1C and the frequency of access to the eMOD system via cellular phone (r = 0.766, P = 0.03; coefficient -0.147). CONCLUSIONS: A1C was improved by a web-based intervention not only via computer but also via cellular phone at 6 months post-initiation in patients with type 2 diabetes. These results indicate that the use of a convenient web-based education system could be more effective for glycemic control than traditional education for diabetes patients.

In-vivo measurements of the dielectric properties of breast carcinoma xenografted on nude mice.

A developing method of cancer detection is to use electromagnetic waves to compare the dielectric properties of normal and cancerous tissue. Because most of the previous studies consisted of dielectric measurements taken ex-vivo, this study investigated the advantages of in-vivo measurements, obtained using the newly developed insertion-type planar probe, through the measurements of cancer (MDA MB 231), which was cultivated and implanted into the mammary fat pad of nude mice. Reflection coefficients were obtained in the broadband frequency range from 0.5 to 30 GHz, from which broadband complex permittivity data was extracted. Complex permittivity, in addition to other parameters such as conductivity and characteristic frequency, were used to make comparisons between cancerous tissue, normal muscle tissue and fat tissue, as well as comparisons between in-vivo and ex-vivo measurements. This study investigated the suitability of in-vivo cancer detection using microwaves with the newly developed insertion-type planar probe. Results showed that both sensitivity and specificity of the current method was 97%. In addition, predictive values were 99% for the positive and 94% for the negative, thus greatly enhancing the practicality of this method. In conclusion, it was demonstrated that in-vivo measurements are highly beneficial in studying the potential of microwaves as a diagnostic tool of breast cancer, especially in combination with the newly developed insertion-type planar probe.

Microwave detection of metastasized breast cancer cells in the lymph node; potential application for sentinel lymphadenectomy.

Metastasis is the leading cause of death in breast cancer patients and an appropriate detection of metastasis can provide better prognosis and quality treatments. Microwaves can reveal the unique electromagnetic properties of materials, and this study aims to unleash the electromagnetic properties of breast cancer cells, especially, metastasized cancer cells in the lymph nodes, using broad-band microwaves in attempts to detect metastases. To distinguish the cancer-specific patterns of cancer tissues, three primary microwave parameters were assessed, i.e., permittivity in mid-band frequency (3-5 GHz), conductivity in high-band frequencies (25-30 GHz) and slope changes of permittivity at high-band frequencies (15-30 GHz). An additional parameter, Cancer Metastasis Index (CMI), was developed to effectively represent all parameters. Broadband microwave scanning can reveal cancer specific electromagnetic behaviors in all three parameters, and these were reliably reflected by CMI. CMI effectively magnified the difference of the electromagnetic properties between normal nodal tissues and cancer tissues. immunohistochemistries were performed to verify the origin of electromagnetic changes represented by CMI values.