Highly Conductive and Long-Term Stable Phosphorene-Based Nanocomposite for Radio-Frequency Antenna Application.

In this study, an omnidirectional and high-performance free-standing monopole patch radio-frequency antenna was fabricated using a urea-functionalized phosphorene/TiO2/polypyrrole (UTP) nanocomposite. The UTP nanocomposite antenna was fabricated via ball milling of urea-functionalized phosphorene, chemical oxidative polymerization of the UTP nanocomposite, and mechanical pelletizing of the composite. Based on experiments, the proposed UTP nanocomposite-based antenna exhibited long-term stability in terms of electrical conductivity. After 12 weeks, a slight change in surface resistance was observed. The proposed antenna exhibited high radiation efficiency (78.2%) and low return loss (-36.6 dB). The results of this study suggest the potential of UTP nanocomposite antennas for applications in 5G technology.

Fabrication of Ternary Titanium Dioxide/Polypyrrole/Phosphorene Nanocomposite for Supercapacitor Electrode Applications.

In this paper, we report a titanium dioxide/polypyrrole/phosphorene (TiO2/PPy/phosphorene) nanocomposite as an active material for supercapacitor electrodes. Black phosphorus (BP) was fabricated by ball milling to induce a phase transition from red phosphorus, and urea-functionalized phosphorene (urea-FP) was obtained by urea-assisted ball milling of BP, followed by sonication. TiO2/PPy/phosphorene nanocomposites can be prepared via chemical oxidative polymerization, which has the advantage of mass production for a one-pot synthesis. The specific capacitance of the ternary nanocomposite was 502.6 F g-1, which was higher than those of the phosphorene/PPy (286.25 F g-1) and TiO2/PPy (150 F g-1) nanocomposites. The PPy fully wrapped around the urea-FP substrate provides an electron transport pathway, resulting in the enhanced electrical conductivity of phosphorene. Furthermore, the assistance of anatase TiO2 nanoparticles enhanced the structural stability and also improved the specific capacitance of the phosphorene. To the best of our knowledge, this is the first report on the potential of phosphorene hybridized with conducting polymers and metal oxides for practical supercapacitor applications.

Mortality rates of hip fracture patients with non-operative treatment.

OBJECTIVES: In this study, we aimed to analyze patient mortality rate after non-operative treatment of hip fractures to determine the distribution of causes of death and to compare factors affecting mortality. PATIENTS AND METHODS: Between January 2013 and March 2019, a total of 93 patients (17 males, 76 females; mean age: 86.0±7.4 years; range, 64 to 98 years) who had hip fractures and were treated non-operatively were analyzed retrospectively. Survival, date of death, and cause of death were collected and analyzed. Baseline demographics, pre-trauma ambulation, pre- and post-trauma residence status, American Society of Anesthesiologists Physical Status (ASA PS) classification, and Parker's mobility score were compared with one-year mortality rates. RESULTS: The mean follow-up of survivors was 16.1±11.9 (range, 6.3 to 79.6) months. The mean survival of non-survivors was 4.9±6.1 (range, 0.007 to 27.3) months. The 3-, 6-, 12-, and 24-month mortality rates were 40.9%, 53.3%, 74.4%, and 87.5%, respectively. Respiratory diseases (33.3%) and cardiovascular diseases (13.6%) were the main causes of death among the patients. There was no statistically significant difference between the patients' age, sex, fracture site, pre-trauma ambulation, pre- and post-trauma residence status, ASA PS classification, Parker's mobility score, and one-year mortality. CONCLUSION: A significant number of patients are still treated non-operatively after hip fractures, and they have a high mortality rate. Efforts and research are needed to reduce mortality and improve the quality of life.

Two-Dimensional Metallic Niobium Diselenide for Sub-micrometer-Thin Antennas in Wireless Communication Systems.

The state-of-the-art of the Internet of things (IoT) and smart electronics demands advances in thin and flexible radio frequency (RF) antennas for wireless communication systems. So far, nanostructured materials such as metals, carbon nanotubes, graphene, MXene, and conducting polymers have been investigated due to their noteworthy electrical conductivity. However, most antennas based on metallic materials are thick, which limits their application in miniaturized and portable electronic devices. Herein, we report two-dimensional (2D) metallic niobium diselenide (NbSe2) for a monopole patch RF antenna, which functions effectively despite its sub-micrometer thickness, which is less than the skin depths of other metals. The as-fabricated antenna has an 855 nm thickness and a 1.2 Ω sq-1 sheet resistance and achieves a reflection coefficient of -46.5 dB, a radiation efficiency of 70.6%, and omnidirectional RF propagation. Additionally, the resonance frequency of this antenna at the same thickness is reconfigured from 2.01 to 2.80 GHz, while decreasing its length and preserving its reflection coefficient of less than -10 dB. This approach offers a facile process to synthesize 2D metallic transition metal dichalcogenides for the rational design of flexible, miniaturized, frequency-tunable, and omnidirectional monopole patch RF antennas for body-centric wearable communication systems.

Reliable Multistate Data Storage with Low Power Consumption by Selective Oxidation of Pyramid-Structured Resistive Memory.

Multilevel data storage using resistive random access memory (RRAM) has attracted significant attention for addressing the challenges associated with the rapid advances in information technologies. However, it is still difficult to secure reliable multilevel resistive switching of RRAM due to the stochastic and multiple formation of conductive filaments (CFs). Herein, we demonstrate that a single CF, derived from selective oxidation by a structured Cu active electrode, can solve the reliability issue. High-quality pyramidal Cu electrodes with a sharp tip are prepared via the template-stripping method. Morphology-dependent surface energy facilitates the oxidation of Cu atoms at the tip rather than in other regions, and the tip-enhanced electric fields can accelerate the transport of the generated Cu ions. As a result, CF growth occurs mainly at the tip of the pyramidal electrode, which is confirmed by high-resolution electron microscopy and elemental analysis. The RRAM exhibits highly uniform and low forming voltages (the average forming voltage and its standard deviation for 20 pyramid-based RRAMs are 0.645 and 0.072 V, respectively). Moreover, all multilevel resistance states for the RRAMs are clearly distinguished and show narrow distributions within 1 order of magnitude, leading to reliable cell-to-cell performance for MLC operation.

Paralabral Cyst of the Hip Compressing Common Femoral Vein Treated with Sono-guided Cyst Aspiration Followed by Arthroscopic Labral Debridement: A Case Report.

Paralabral cyst around hip is reported to be a cause of compression of the major neurovascular structures. Although, arthroscopic cyst and labral debridement is generally accepted as the effective treatment, there is limited literature available regarding treatment options for paralabral cysts in the hip. We present a case of paralabral cyst compressing left common femoral vein in the hip that was treated with sono-guided cyst aspiration followed by arthroscopic labral debridement.

Vitamin D deficiency adversely affects early post-operative functional outcomes after total knee arthroplasty.

PURPOSE: Vitamin D has received considerable attention in recent years owing to the increasing evidence of its importance in muscle function and physical performance. The present study attempted to determine whether patients with low serum vitamin D levels had impairment in early functional outcomes following total knee arthroplasty (TKA). METHODS: This was a prospective cohort study that included 92 patients. Patients were divided into two groups according to their vitamin D levels as assessed at the preoperative visit: (1) vitamin D-deficient group, serum 25-hydroxyvitamin D3 (25(OH)D) levels <12 ng/mL; (2) vitamin D non-deficient group, serum 25(OH)D levels ≥12 ng/mL. American Knee Society Score (KSS) and four other performance tests including the alternative step test (AST), six-metre walk test (SMT), sit-to-stand test (STS), and timed up and go test (TUGT) were used for assessment of post-operative function. All assessments were performed one day before and three months after TKA. RESULTS: Of the 92 patients included in the study, 87 patients performed all required assessments. The mean post-operative functional KSS was significantly lesser in the vitamin D-deficient group than in the vitamin D non-deficient group (67.2 vs. 73.4, p = 0.031). The mean values of time taken for post-operative AST (16.6 vs. 14.6 s, p = 0.033) and SMT (8.8 vs. 7.7 s, p = 0.012) were significantly longer in the vitamin D-deficient group than in the vitamin D non-deficient group. Post-operative STS and TUGT demonstrated higher values for mean time taken in the vitamin D-deficient group than in the vitamin D non-deficient group, but these were not statistically significant (13.6 vs. 12.4 s, not significant (n.s.); 12.7 vs. 11.7 s, n.s., respectively). CONCLUSION: Early post-operative functional outcomes following TKA appear to be adversely affected by vitamin D deficiency. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

Reversibly Stretchable, Optically Transparent Radio-Frequency Antennas Based on Wavy Ag Nanowire Networks.

We report a facile approach for producing reversibly stretchable, optically transparent radio-frequency antennas based on wavy Ag nanowire (NW) networks. The wavy configuration of Ag NWs is obtained by floating the NW networks on the surface of water, followed by compression. Stretchable antennas are prepared by transferring the compressed NW networks onto elastomeric substrates. The resulting antennas show excellent performance under mechanical deformation due to the wavy configuration, which allows the release of stress applied to the NWs and an increase in the contact area between NWs. The antennas formed from the wavy NW networks exhibit a smaller return loss and a higher radiation efficiency when strained than the antennas formed from the straight NW networks, as well as an improved stability in cyclic deformation tests. Moreover, the wavy NW antennas require a relatively small quantity of NWs, which leads to low production costs and provides an optical transparency. These results demonstrate the potential of these wavy Ag NW antennas in applications of wireless communications for wearable systems.

Highly Omnidirectional and Frequency Controllable Carbon/Polyaniline-based 2D and 3D Monopole Antenna.

Highly omnidirectional and frequency controllable carbon/polyaniline (C/PANI)-based, two- (2D) and three-dimensional (3D) monopole antennas were fabricated using screen-printing and a one-step, dimensionally confined hydrothermal strategy, respectively. Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties. Compared to antennas composed of pristine carbon or PANI-based 2D monopole structures, 2D monopole antennas composed of this enhanced hybrid material were highly efficient and amenable to high-frequency, omnidirectional electromagnetic waves. The mean frequency of C/PANI fiber-based 3D monopole antennas could be controlled by simply cutting and stretching the antenna. These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna. These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate. This approach offers a valuable and promising tool for producing highly omnidirectional and frequency-controllable, carbon-based monopole antennas for use in wireless networking communications on industrial, scientific, and medical (ISM) bands.

Enhanced magnetorheological performance of highly uniform magnetic carbon nanoparticles.

Magnetic carbon nanoparticles (MC NPs) are prepared on a multi-gram scale through carbonization of iron-doped polypyrrole nanoparticles (PPy NPs). Three different-sized MC NPs (ca. 40, 60 and 90 nm) are prepared and adopted as dispersing materials for magnetorheological (MR) fluids to investigate the influence of particle size on MR properties. The MC NP-based MR fluids exhibit outstanding MR performances compared to the conventional magnetic carbon material-based fluids. In addition, the MR activities are enhanced with decreasing particle diameter and increasing applied magnetic field strength. Furthermore, anti-sedimentation properties are examined in order to achieve in-depth insight into the effect of the particle size on MR fluids.

Highly sensitive and multifunctional tactile sensor using free-standing ZnO/PVDF thin film with graphene electrodes for pressure and temperature monitoring.

We demonstrate an 80-µm-thick film (which is around 15% of the thickness of the human epidermis), which is a highly sensitive hybrid functional gauge sensor, and was fabricated from poly(vinylidene fluoride) (PVDF) and ZnO nanostructures with graphene electrodes. Using this film, we were able to simultaneously measure pressure and temperature in real time. The pressure was monitored from the change in the electrical resistance via the piezoresistance of the material, and the temperature was inferred based on the recovery time of the signal. Our thin film system enabled us to detect changes in pressure as small as 10 Pa which is pressure detection limit was 10(3)-fold lower than the minimum level required for artificial skin, and to detect temperatures in the range 20-120 °C.

The Results of Long-term Follow-up of Total Hip Arthroplasty Using Hydroxyapatite-coated Cups.

PURPOSE: The aim of this study was to report the long-term outcome and the failure mechanism of cementless total hip arthroplasty (THA) using hydroxyapatite (HA)-coated acetabular cup. MATERIALS AND METHODS: From January 1992 to May 1994, a total of 123 consecutive cementless primary THAs were performed using a HA-coated acetabular cup with metal-on-polyethylene articulation. We retrospectively evaluated 66 hips available for follow-up at a mean 18.3 years (range, 10.4-23.6 years). The survival analysis was performed by the Kaplan-Meier method. We defined end point as any failure that required a reoperation of acetabular component. RESULTS: Thirty-nine of 66 hips (59.1%) were defined as a failure for progressive acetabular osteolysis or aseptic loosening of the cup. Acetabular osteolysis was observed in 47 hips (71.2%) and 33 hips (50.0%) were revised because of cup loosening. The Kaplan-Meier method showed the survival rate of the acetabular cup to be 46.3% at 15 years and 34.8% at 20 years for any failure that required a reoperation of acetabular component. CONCLUSION: The long-term survival rate of THA using HA-coated acetabular cup was unsatisfactory, and it was attributed to vulnerable property of HA coating and progressive osteolysis.

Clinical outcomes of the endoscopic submucosal dissection of early gastric cancer are comparable between absolute and new expanded criteria.

BACKGROUND/AIMS: Advances in endoscopic submucosal dissection (ESD) techniques have led to the development of expanded criteria for endoscopic resection of early gas-tric cancer (EGC). The aim of this study was to evaluate the short- and long-term outcomes for ESD using indication cri-teria. METHODS: A total of 1,105 patients underwent ESD for EGC at six medical centers. The patients were classified into the following two groups based on the lesion size, presence of ulceration and pathological review an absolute criteria group (n=517) and an expanded criteria group (n=588). RESULTS: The curative resection rates (91.1% vs 91.3%, p=0.896) were similar in the absolute criteria group and the expanded criteria group. The en bloc resection rates (93.4% and 92.3%, respectively; p=0.488) and complete resection rates (98.3% and 97.4%, respectively; p=0.357) did not differ between the groups. The cumulative disease-free survival rates and the overall survival rates were similar between the groups (p=0.778 and p=0.654, respectively). Independent factors for the curative resection of EGC included tumor lo-cation (upper vs middle and lower, 2.632 [1.128-6.144] vs 3.497 [1.560-7.842], respectively) and en bloc resection rate 12.576 [7.442-21.250]. CONCLUSIONS: The expanded criteria for ESD in cases of EGC is comparable with the widely ac-cepted pre-existing criteria. (Gut Liver, 2015;9181-187).

Highly conductive, flexible and scalable graphene hybrid thin films with controlled domain size as transparent electrodes.

Highly conductive, transparent, flexible and scalable graphene hybrid thin films with controlled domain size were successfully fabricated via a mechanochemical method, screen printing and pressure-assisted reduction process.

Graphene size control via a mechanochemical method and electroresponsive properties.

Highly dispersible graphene oxide (GO) sheets of uniform submicrometer size were successfully fabricated from pristine graphite using a simple mechanochemical process. The GO flake morphology was transformed into a spherical form, and the density was decreased slightly via the ball-milling process. Ball-milled GO can be used as an electrorheological (ER) material because of its small particle size, low conductivity, and outstanding dispersibility in silicone oil. We found that the 2-h ball-milled GO-based ER fluid had the best ER performance (shear stress of 78.5 Pa and 630% ER efficiency), which was double that of the nonmilled GO-based ER fluid. The response time to form a fibrillar structure along the applied electric field direction and the recovery time to the starting level decreased with increasing ball-milling time. Additionally, the retarded settling velocity of isolated GO sheets and the electrostatic repulsion between oxygen functional groups on the GO sheets combined to improve the antisedimentation property. The ability to control the size of graphene sheets is a great opportunity to advance graphene commercialization in a high-quality, scalable production setting.

One-step fabrication of a highly conductive and durable copper paste and its flexible dipole tag-antenna application.

A highly conductive and durable copper (Cu) paste was successfully fabricated via acid treatment and mechanical blending with corrosion inhibitors. A screen-printed Cu pattern was evaluated as a dipole tag-antenna with long term and thermal stability, and structural flexibility.

Enhanced frequency response of a highly transparent PVDF-graphene based thin film acoustic actuator.

A high-performance polyvinylidene fluoride (PVDF) based thin film acoustic actuator with chemical vapor deposition (CVD) graphene electrodes was successfully fabricated. Importantly, it showed 60, 19, and 22% enhancement in the bass, middle and treble frequency response, respectively.

Graphene/polyaniline/poly(4-styrenesulfonate) hybrid film with uniform surface resistance and its flexible dipole tag antenna application.

A graphene/polyaniline/poly(4-styrenesulfonate) (G/PANI/PSS)-based conducting paste is successfully fabricated by introducing a PANI/PSS nanofiller into a multilayer graphene matrix by mechanical blending. As a compatibilizer, the PSS binder increases the dispersibility, interfacial interactions, and mechanical interlocking between the multilayer graphene matrix and PANI, thereby allowing surface resistance with narrow distribution. High concentrations of this PSS binder, obtained using ex situ polymerization, further improve the adhesion of the hybrid film to a flexible substrate. The minimum surface resistance of the screen-printed G/PANI/PSS hybrid film is approximately 10 Ω sq(-1) for a 70 µm uniform thickness. When bent to angles of -30°, the flexible hybrid film exhibits an approximately 6% decrease in surface resistance. The surface resistance after 500 bending cycles increases by only 10 Ω sq(-1) , which is 14 times that of smaller, graphene-based thin films. The micropatterned, screen-printed G/PANI/PSS hybrid film is evaluated as a practical dipole tag antenna. High-resolution patterns are formed in the hybrid film by the inherently high surface tension and the properties of grains within the domain-based structure. The G/PANI/PSS-based dipole tag antenna has a bandwidth of 28.7 MHz, a high transmitted power efficiency of 98.5%, and a recognition distance of 0.42 m at a mean frequency of 910 MHz. These characteristics indicate that the G/PANI/PSS-based dipole tag antenna could be used as a signal-receiving apparatus, much like a radio-frequency identification tag, for detecting nearby objects.

Spatially controlled carbon sponge for targeting internalized radioactive materials in human body.

Carbon sponge, an adsorbent with spatially controlled structure is demonstrated for targeting internalized radiocesium and other radionuclides in human body. Three dimensionally ordered macroporous (3DOM) carbons derived from inverse opal replicas of colloidal-crystal template exhibit large surface area and high porosity, resulting in highly efficient adsorbents for radionuclides. It is also possible to enhance binding affinity and selectivity to radionuclide targets by decoration of 3DOM carbon surfaces with Prussian blue (PB) nanoparticles, and synthesized PB nanoparticles reveal low toxicity toward macrophage cells with potential advantages over oral administration. It is noteworthy that the maximum (133)Cs adsorption capacity of PB-decorated 3DOM carbons is 40.07 mmol g(-1) which is ca. 30 and 200 times higher than that of commercialized medicine Radiogardase(®) and bulk PB, respectively. Further, adsorption kinetics study indicates that the PB-decorated 3DOM carbons have the homogenous surface for (133)Cs ion adsorption and all sites have equal adsorption energies in terms of ion exchange between the cyano groups of the PB-decorated 3DOM carbons and radionuclides. As a concept of the oral-administrable "carbon sponge", the PB-decorated 3DOM carbons offer useful implications in the separation science of radioactive materials and important insight for designing novel materials for treatment of patients or suspected internal contamination with radioactive materials.

The cap-assisted technique enhances colonoscopy training: prospective randomized study of six trainees.

BACKGROUND: Colonoscopy and polypectomy procedures have effectively reduced the incidence of colorectal cancer. Currently, competence in colonoscopy is an essential part of the education program for gastrointestinal (GI) trainees. However, considerable training is required for the optimal performance of a colonoscopy. METHODS: This study involved six colonoscopy trainees, three of whom used the cap whereas the others did not. Each trainee managed 100 cases of screening colonoscopy from beginning to end. The cecal intubation success rate, cecal intubation time, polyp detection rate, adenoma detection rate, advanced adenoma detection rate, and adenocarcinoma detection rate were checked. The rate of successful cecal intubation and the cecal intubation time were reviewed every 10 cases. RESULTS: The cecal intubation rate was 80.7 % (242/300) in the cap group and 63.3 % (190/300) in the non-cap group. The average cecal intubation time was 13.7 min in the cap group and 18.7 min in the non-cap group. The statistical analysis of these results suggested that the cap group had a significantly higher success rate (p < 0.001) and a shorter cecal intubation time (p < 0.001) than the non-cap group. However, the two groups did not differ significantly in the detection rate for polyps (45.3 vs 43 %; p = 0.565), adenomas (26.3 vs 25 %; p = 0.709), advanced adenomas (2.6 vs 0.6 %; p = 0.056), or adenocarcinomas (5.3 vs 3 %; p = 0.153). CONCLUSION: Cap-assisted colonoscopies might help to increase the rate of cecal intubation success and shorten the cecal intubation time for GI trainees.