Chiral Diketopyrrolopyrrole-Based Conjugated Polymers with Intramolecular Rotation-Isomeric Conformation Asymmetry for Near-Infrared Circularly Polarized Light-Sensing Organic Phototransistors

Recent advances in chiral nanomaterials interacting with circularly polarized (CP) light open new expectations for optoelectronics in various research fields such as quantum- and biology-related technology. To fully utilize the great potential of chiral optoelectronic devices, the development of chiral optoelectronic devices that function in the near-infrared (NIR) region is required. Herein, we demonstrate a NIR-absorbing, chiroptical, low-band-gap polymer semiconductor for high-performance NIR CP light phototransistors. A newly synthesized diketopyrrolopyrrole-based donor-acceptor-type chiral π-conjugated polymer with an asymmetric alkyl side chain exhibits strong chiroptical activity in a wavelength range of 700-1000 nm. We found that the attachment of an enantiomerically pure stereogenic alkyl substituent to the π-conjugated chromophore backbone led to strong chiroptical activity through symmetry breaking of the π-conjugation of the backbone in a molecular rotational motion while maintaining the coplanar backbone conformation for efficient charge transport. The NIR CP light-sensing phototransistors based on a chiral π-conjugated polymer photoactive single channel layer exhibit a high photoresponsivity of 26 A W-1 under NIR CP light irradiation at 920 nm, leading to excellent NIR CP light distinguishability. This study will provide a rationale and strategy for designing chiral π-conjugated polymers for high-performance NIR chiral optoelectronics.

Chiroptical Synaptic Heterojunction Phototransistors Based on Self-Assembled Nanohelix of π-Conjugated Molecules for Direct Noise-Reduced Detection of Circularly Polarized Light

High-performance chiroptical synaptic phototransistors are successfully demonstrated using heterojunctions composed of a self-assembled nanohelix of a π-conjugated molecule and a metal oxide semiconductor. To impart strong chiroptical activity to the device, a diketopyrrolopyrrole-based π-conjugated molecule decorated with chiral glutamic acid is newly synthesized; this molecule is capable of supramolecular self-assembly through noncovalent intermolecular interactions. In particular, nanohelix formed by intertwinded fibers with strong and stable chiroptical activity in a solid-film state are obtained through hydrogen-bonding-driven, gelation-assisted self-assembly. Phototransistors based on interfacial charge transfer at the heterojunction from the chiroptical nanohelix to the metal oxide semiconductor show excellent chiroptical detection with a high photocurrent dissymmetry factor of 1.97 and a high photoresponsivity of 218 A W-1 . The chiroptical phototransistor demonstrates photonic synapse-like, time-dependent photocurrent generation, along with persistent photoconductivity, which is attributed to the interfacial charge trapping. Through the advantage of synaptic functionality, a trained convolutional neural network successfully recognizes noise-reduced circularly polarized images of handwritten alphabetic characters with better than 89.7% accuracy.

Fibriform Organic Electrochemical Diodes with Rectifying, Complementary Logic and Transient Voltage Suppression Functions for Wearable E-Textile Embedded Circuits

In this study, a fibriform electrochemical diode capable of performing rectifying, complementary logic and device protection functions for future e-textile circuit systems is fabricated. The diode was fabricated using a simple twisted assembly of metal/polymer semiconductor/ion gel coaxial microfibers and conducting microfiber electrodes. The fibriform diode exhibited a prominent asymmetrical current flow with a rectification ratio of over 10², and its performance was retained after repeated bending deformations and washings. Fundamental studies on the electrochemical interactions of polymer semiconductors with ions reveal that the Faradaic current generated in polymer semiconductors by electrochemical reactions results in an abrupt current increase under a forward bias, in which the threshold voltages of the device are determined by the oxidation or reduction potential of the polymer semiconductor. Textile-embedded full-wave rectifiers and logic gate circuits were implemented by simply integrating the fibriform diodes, exhibiting AC-to-DC signal conversion and logic operation functions, respectively. It was also confirmed that the proposed fibriform diode can suppress transient voltages and thus protect a low-voltage operational wearable e-textile circuit.

Integration of synaptic phototransistors and quantum dot light-emitting diodes for visualization and recognition of UV patterns

Synaptic photodetectors exhibit photon-triggered synaptic plasticity, which thus can improve the image recognition rate by enhancing the image contrast. However, still, the visualization and recognition of invisible ultraviolet (UV) patterns are challenging, owing to intense background noise. Here, inspired by all-or-none potentiation of synapse, we develop an integrated device of synaptic phototransistors (SPTrs) and quantum dot light-emitting diodes (QLEDs), facilitating noise reduction and visualization of UV patterns through on-device preprocessing. The SPTrs convert noisy UV inputs into a weighted photocurrent, which is applied to the QLEDs as a voltage input through an external current-voltage-converting circuit. The threshold switching characteristics of the QLEDs result in amplified current and visible illumination by the suprathreshold input voltage or nearly zero current and no visible illumination by the input voltage below the threshold. The preprocessing of image data with the SPTr-QLED can amplify the image contrast, which is helpful for high-accuracy image recognition.

Photo-Curable Lacquer Sap Resin Based on Urushiol-Mimicking, Tyrosine-Containing Additive

Oriental lacquer sap is attracting considerable attention as a renewable and eco-friendly natural resin with high durability, heat resistance, insulation, insect repellency, and antiseptic and antibacterial properties. However, to ensure excellent coating performance, it is necessary to improve the drying/curing process of lacquer sap with a time-consuming drying time at high humidity [relative humidity (RH), 70-90%] and ambient temperature (20-30 °C). Drawing on an understanding of the polymerization mechanism of urushiol, the main component of the lacquer sap consisted of a water-in-oil (W/O) emulsion, and this study presents an eco-friendly additive that mimics the structure-function of urushiol composed of a polar catechol head group and a nonpolar hydrocarbon tail. A photo-curable lacquer sap was thus developed by adding a tyrosine amino acid-based lipid agent (denoted as Y-ADDA), which allows faster and more effective drying/curing at lower humidity while maintaining the nature-derived properties of lacquer sap. Y-ADDA easily coassembles with urushiol in the W/O emulsion droplets, thereby significantly accelerating the formation of a polymer network along with urushiol during water evaporation leading to fast drying/curing under ultraviolet (UV) light irradiation at low humidity (∼50% RH). The UV-cured lacquer sap resins showed higher performance in terms of film processing and physicochemical properties compared with that of the lacquer containing only tyrosine amino acids without aliphatic tail conjugation, N-(9-fluorenylmethoxycarbonyl)-O-tert-butyl-l-tyrosine Fmoc-Tyr(tBu)-OH. Furthermore, the drying and curing times, film morphology, transmittance, hardness, and adhesion strength of the UV-cured lacquer were markedly superior compared to those of shellac, a general eco-friendly fast-drying primer. The study provides useful strategies and insights to promote the industrial application of lacquer sap resins by employing biocompatible nanoagents developed with an understanding of the curing mechanism of natural resins and from the viewpoint of green and sustainable chemistry perspective.

Precrystalline P3HT nanowires: growth-controllable solution processing and effective molecular packing transfer to thin-film

Solution-processable precrystalline nanowires (NWs) of conjugated polymers (CPs) have garnered significant attention in fundamental research based on crystallization-driven self-assembly and in the roll-to-roll fabrication of optoelectronic devices such as organic...

537 Open vs Closed Pilon Fractures: Comparison of Management, Outcomes, and Complications

Aim

Despite the low incidence of pilon fractures, their high impact nature presents difficulties in surgical management/recovery. Current literature is varied, with no universal treatment algorithm. We aim to highlight differences in treatment, outcomes, complications between open and closed pilon fractures.

Method

This retrospective study was conducted at a major trauma centre, including patients over 5-year period. 135 patients were included (open:48, closed:87). Primary outcome was AOFAS score at 3-, 6- and 12-months post-injury. Secondary outcomes include time to partial weight-bear (PWB) and full weight-bear (FWB), bone union time, follow-up time. Post-operative complications were collected.

Results

Open fractures had lower AOFAS score 3 months post-injury, longer bone union time, and time to FWB. For both open and closed fractures, compared to ORIF patients, those treated with fine wire fixator (FWF) had lower AOFAS scores 3- and 6-months post-injury. Closed fracture patients treated with ORIF had shorter bone union time, time to PWB and FWB. Patients with AO/OTA 43A fractures needed shorter time to PWB and FWB than those with 43C fractures. Common complications (closed:open) were superficial infection (22%:54%), post-traumatic arthritis (25%:16%), non-union (11%:24%).

Conclusions

Open fractures, with more extensive soft tissue damage, were likely more suited for FWF, rather than ORIF (18% of open vs 72% of closed were treated with ORIF). Due to greater associated trauma, more frequent complications, and delayed definitive fixation, open fractures had lower AOFAS scores. Nevertheless, use of staged approach involving temporary external fixation, followed with ORIF or FWF achieved low complication rates and good functional recovery.

33 Impact of Disruption of Tibio-Fibular Joints During Distraction Osteogenesis on Knee and Ankle Joint Function

Aim

The aim of this study is to investigate whether a disruption of proximal and/or distal tibio-fibular joint correlates to patient’s function and osteoarthritis.

Method

Retrospective analysis of 44 patients with lower limb bone defects treated by tibial corticotomy and distraction osteogenesis was conducted. Analysis of lower limb x-rays before surgery, immediately post-surgery and after frame removal permitted calculations of changes in tibial length and changes in fibula position relative to the tibia at the proximal and distal tibio-fibular joints. X-rays before and after treatment were also graded for osteoarthritis severity using Alhbäck's classification. Functional ability was scored using the American Orthopaedic Foot & Ankle Society (AOFAS) score and the Knee society score (KSS).

Results

15 patients showed a decrease in the distance between fibular tip and distal tibia, 5 showed no change and 12 showed an increase at the end of the treatment. No statistical significant association was noted with KSS or AOFAS score (p > 0.05), however one patient with a large distance increase exhibited severe radiological exacerbation of knee osteoarthritis. The distal corticotomy group achieved significantly higher length of new bone (p < 0.001) and were more likely to have exacerbation of knee osteoarthritis (p < 0.05). Conversely, proximal corticotomy group were significantly more likely to show an exacerbation of ankle osteoarthritis (p < 0.05).

Conclusions

Attempts should be made not to disrupt the tibio-fibular joints during bone transport, but disruption does not necessarily correlate to poorer outcomes. Our results show that lengthening index reduces with larger bone defects, suggesting that radical debridement/resection may not negatively affect the healing index.

Dendritic Network Implementable Organic Neurofiber Transistors with Enhanced Memory Cyclic Endurance for Spatiotemporal Iterative Learning

Dendritic network implementable organic neurofiber transistors with enhanced memory cyclic endurance for spatiotemporal iterative learning are proposed. The architecture of the fibrous organic electrochemical transistors consisting of a double-stranded assembly of electrode microfibers and an iongel gate insulator enables the highly sensitive multiple implementation of synaptic junctions via simple physical contact of gate-electrode microfibers, similar to the dendritic connections of a biological neuron fiber. In particular, carboxylic-acid-functionalized polythiophene as a semiconductor channel material provides stable gate-field-dependent multilevel memory characteristics with long-term stability and cyclic endurance, unlike the conventional poly(alkylthiophene)-based neuromorphic electrochemical transistors, which exhibit short retention and unstable endurance. The dissociation of the carboxylic acid of the polythiophene enables reversible doping and dedoping of the polythiophene channel by effectively stabilizing the ions that penetrate the channel during potentiation and depression cycles, leading to the reliable cyclic endurance of the device. The synaptic weight of the neurofiber transistors with a dendritic network maintains the state levels stably and is independently updated with each synapse connected with the presynaptic neuron to a specific state level. Finally, the neurofiber transistor demonstrates successful speech recognition based on iterative spiking neural network learning in the time domain, showing a substantial recognition accuracy of 88.9%.

Sympathetic predominance before tourniquet deflation is associated with a reduction in arterial blood pressure after tourniquet deflation during total knee arthroplasty

High dependency of arterial blood pressure (ABP) on enhanced sympathetic activity, which maintains vascular tone, leads to hypotension after hemodynamic insults that blunt the sympathetic activity. Therefore, we hypothesized that sympathovagal balance before tourniquet deflation (TD) determines the extent of a reduction in ABP after TD during total knee arthroplasty (TKA). Fifty-four hypertensive female patients undergoing TKA under spinal anesthesia were analyzed. The sympathovagal balance [low-to-high frequency ratio of heart rate variability (LF/HF)] before TD was defined as (LF/HF during 5 min before TD-preanesthetic LF/HF)/preanesthetic LF/HF (%). An increase in its value represents a shift in sympathovagal balance toward sympathetic predominance. The percent change in the mean ABP (MAP) after TD was defined as (minimum MAP during 10 min after TD-averaged MAP during 5 min before TD)/averaged MAP during 5 min before TD (%). Simple linear regression was performed to assess the correlation between the sympathovagal balance before TD and change in MAP after TD. The correlation was also assessed by multiple linear regression controlling for age, duration of tourniquet inflation, and spinal anesthesia-induced hypotension. Thirty-two minutes (on average) after tourniquet inflation, the MAP was decreased by 12.1 (-3.0 to 47.9) % [mean (range)] upon TD (P<0.001). The sympathovagal balance before TD was negatively proportional to the change in MAP after TD in both simple and multiple linear regression models (R2=0.323 and 0.340, P<0.001). A shift in sympathovagal balance toward sympathetic predominance before TD is associated with a decrease in ABP after TD.

Nano-emulsification of oriental lacquer sap by ultrasonic wave propagation: Improvement of thin-film characteristics as a natural resin

Lacquer sap has received much attention as a traditional natural resin because it is a renewable and eco-friendly biopolymer resource unlike artificial coating materials. However, strict drying conditions and long drying times of lacquer sap should be modified to expand its applications. This study presents the first attempt to investigate the effect of different amplitudes of ultrasonic waves on the lacquer sap composed of water-in-oil (W/O) emulsion droplets and the mechanical properties of the resultant film by solvent evaporation. Acoustically induced cavitation via batch ultrasonication facilitates the generation of submicron-sized W/O emulsion. The drying time of sonicated lacquer sap was noticeably shortened as the amplitude of acoustic power increased. Interestingly, the transparency of the film cast from lacquer sap consisting of the smallest emulsion droplets increased significantly, weakening the degree of colour change from caramel-like yellow to dark brown as polymerisation progressed. These are attributed to the effective and frequent contact of laccase enzyme with urushiol at the increased interfacial area of nano-emulsified W/O droplets pulverised by ultrasonic waves. The quinone radical-generation in the interface layer and its transfer to the urushiol oil phase through water-insoluble glycoprotein emulsifier are greatly promoted, resulting in highly cross-linked, dense three-dimensional polymer networks, which also increased the lacquer film hardness after drying. As the emulsion droplet size decreased, the mutual interaction between the catechol moiety of urushiol and the substrates increased, resulting in improved adhesion. The nano-emulsification of the lacquer sap by ultrasonic waves can be used in a simple, effective, and eco-friendly way to shorten the drying time and improve the film characteristics of natural resins. This approach could pave the way for its wide range of applications in industrial fields, taking into account green and sustainable chemistry.

Longitudinal Changes of High Molecular Weight Adiponectin are Associated with Postpartum Development of Type 2 Diabetes Mellitus in Patients with Gestational Diabetes Mellitus

BACKGROUND

The influence of serial changes of adipokines on maternal glucose metabolism from pregnancy to postpartum periods in women with previous gestational diabetes mellitus (pGDM) has not been thoroughly explored. We tried to examine the relationship between the serial changes of adipokines and the development of diabetes mellitus (DM) in women with pGDM.

METHODS

We longitudinally measured following adipokines: high molecular weight (HMW) adiponectin, retinol-binding protein-4 (RBP-4), lipocalin-2, and chemerin, during pregnancy, and at 2 months and 3 years after delivery. Based on glucose status at postpartum 3 years, we divided into three groups: normal glucose tolerance (GDM-NGT, n=20), impaired glucose tolerance (GDM-IGT, n=23), and GDM-DM (n=22). We analyzed the correlations between adipokines and various metabolic parameters.

RESULTS

Plasma HMW adiponectin levels were not different among the three groups during pregnancy. However, HMW adiponectin levels increased at 3 years after the delivery in women with GDM-NGT compared with women with GDM-DM. In the GDM-IGT group, HMW adiponectin levels increased at 2 months postpartum compared to pregnancy period. In contrast, HMW adiponectin levels showed no alternation after parturition in women with GDM-DM. HMW adiponectin was negatively correlated with body mass index and a homeostasis model assessment of insulin resistance. Other adipokines such as RBP-4, lipocalin-2, and chemerin neither showed any differences among the groups nor any significant correlations with 3 years postpartum status of glucose intolerance.

CONCLUSION

Serial changes of HMW adiponectin are associated with the maintenance of glucose metabolism in women with pGDM after delivery.

Spirally Wrapped Carbon Nanotube Microelectrodes for Fiber Optoelectronic Devices beyond Geometrical Limitations toward Smart Wearable E-Textile Applications

Fiber optoelectronics technology has recently attracted attention as enabling various form factors of wearable electronics, and the issue of how to control and optimize the configuration and physical properties of the electrode micropatterns in the microfiber devices has become important. Here, spirally wrapped carbon nanotube (CNT) microelectrodes with a controlled dimension are demonstrated for high-performance fiber optoelectronic devices. Inkjet-printed CNT microelectrodes with the desired dimension on an agarose hydrogel template are rolling-transferred onto a microfiber surface with an efficient electrical interface. A fiber organic field-effect transistor with spirally wrapped CNT microelectrodes verifies the feasibility of this strategy, where the transferred microelectrodes intimately contact the organic semiconductor active layer and the output current characteristics are simply controlled, resulting in characteristics that exceed the previous structural limitations. Furthermore, a fiber organic photodiode with spirally wrapped CNT microelectrodes, when used as a transparent electrode, exhibits a high I_light/I_dark ratio and good durability of bending. This fiber photodiode can be successfully incorporated into a textile photoplethysmography bandage for the real-time monitoring of human vital signals. This work offers a promising and efficient strategy to overcome the geometric factors limiting the performance of fiber-optic optoelectronic devices.

Ecofriendly Catechol Lipid Bioresin for Low-Temperature Processed Electrode Patterns with Strong Durability

We demonstrated catechol lipid-based bioresin, which is collected from lacquer trees, to produce conductive pastes that can be processed at low temperatures, which are highly adhesive and multidurable. Our conductive paste, which consists of catechol lipid-based urushiol resin and a multimodal mixture of silver fillers, exhibited stable dispersion with shear thinning properties. The urushiol lacquer induced spontaneous reduction of silver salt at the surface of the silver fillers, thereby contributing to lower the contact resistance between conductive fillers in the electrical conduction. Furthermore, the directional volume shrinkage of the urushiol lacquer matrix in a cross-linking reaction resulted in a highly ordered microstructure of the silver fillers with layer-by-layer stacking of the silver flakes. This structure contributed to the improvement of the electrical contact between fillers as well as excellent mechanical hardness, anti-scratch capability, and the long-term environmental stability of the conductive films. Conductive films based on the silver paste with urushiol lacquer exhibited low electrical resistivity below 4.4 × 10^-5 Ω cm, 5B-class strong adhesion strength, and high hardness exceeding 200 MPa. Finally, we demonstrated the facile room-temperature processability and screen printability of the UL-Ag paste by fabricating a printed antenna and three-dimensional (3D) electrode assembly based on a plastic 3D block.

Stretchable Conductive Adhesives with Superior Electrical Stability as Printable Interconnects in Washable Textile Electronics

As practical interest in stretchable electronics increases for future applications in wearables, healthcare, and robotics, the demand for electrical interconnects with high electrical conductivity, durability, printability, and adhesion is growing. Despite the high electrical conductivity and stretchability of most previous interconnects, they lack stable conductivity against strain and adhesion to stretchable substrates, leading to a limitation for their practical applications. Herein, we propose a stretchable conductive adhesive consisting of silver particles with carbon nanotube as an auxiliary filler in silicone adhesives. The conductive adhesive exhibits a high initial conductivity of 6450 S cm^-1. They show little change in conductivity over 3000 stretching cycles at 50% strain, currently the highest stability reported for elastic conductors. Based on strong adhesion to stretchable substrates, the gel-free, dry adhesives printed on an elastic bandage for electrocardiography monitoring exhibit an extremely stable performance upon movement of the subject, even after several cycles of detachment-reattachment and machine washing.

Low-Voltage Organic Transistor Memory Fiber with a Nanograined Organic Ferroelectric Film

Wearable technology offers new ways to be more proactive about our health and surroundings in real time. For next-generation wearable systems, robust storage and recording media are required to monitor and process the essential electrical signals generated under various unpredictable strain conditions. Here, we report the first fibriform organic transistor memory integrated on a thin and flexible metal wire. A capillary tube coating system allows the formation of a thin and nanograined organic ferroelectric film on the wire. The uniform morphology imparts excellent switching stability (∼100 cycles), quasi-permanent retention (over 5 × 10⁴ s), and low-voltage operation (below 5 V) to the fiber-shaped memory devices. When sewn in a stretchable textile fabric, the memory fiber achieves long retention time of more than 10⁴ s with negligible degradation of memory window even under a constant diagonal strain of 100% that exhibits reliable data storage under tough environments. These results illustrate the possibility of the practical, wearable fiber memory for recording electronic signals in smart garment applications.

Hydrogel-Templated Transfer-Printing of Conductive Nanonetworks for Wearable Sensors on Topographic Flexible Substrates

Transfer-printing enables the assembly of functional nanomaterials on unconventional substrates with a desired layout in a controllable manner. However, transfer-printing to substrates with complex surfaces remains a challenge. Herein, we show that hydrogels serve as effective template material platforms for the assembly and transfer-printing of conductive nanonetwork patterns for flexible sensors on various topographic surfaces in a very simple yet versatile manner. The non-adherence, nanoporous structure, and molding capability of the hydrophilic hydrogel enable the assembly of conductive nanonetwork patterns on the hydrogel surface and transfer of the nanonetworks onto various flexible and topographic substrates. Flexible strain sensors and pressure sensors that monitor finger motions and arterial pulses are successfully demonstrated using the hydrogel-templated approach. The rich chemistry of polymeric networks, facile molding capability, and biocompatibility of hydrogels could be further combined with additive technology for hydrogels and electronic materials for emerging four-dimensional functional materials and soft bioelectronics.

A New Architecture for Fibrous Organic Transistors Based on a Double-Stranded Assembly of Electrode Microfibers for Electronic Textile Applications

Herein, a unique device architecture is proposed for fibrous organic transistors based on a double-stranded assembly of electrode microfibers for electronic textile applications. A key feature of this work is that the semiconductor channel of the fiber transistor comprises a twist assembly of the source and drain electrode microfibers that are coated by an organic semiconductor. This architecture not only allows the channel dimension of the device to be readily controlled by varying the thickness of the semiconductor layer and the twisted length of the two electrode microfibers, but also passivates the device without affecting interconnections with other electrical components. It is found that the control of crystalline nanostructure of the semiconductor layer is critical for improving both the production yield of the device and the charge-carrier transport in the device. The resulting fibrous organic transistors show a high output current of over -5 mA at a low operation voltage of -1.3 V and a good on/off current ratio of 10⁵ . The device performance is maintained after repeated bending deformation and washing with a strong detergent solution. Application of the fibrous organic transistors to switch current-driven LED devices and detection of electrocardiography signals from a human body are demonstrated.

Effect of Crystallization Modes in TIPS-pentacene/Insulating Polymer Blends on the Gas Sensing Properties of Organic Field-Effect Transistors

Blending organic semiconductors with insulating polymers has been known to be an effective way to overcome the disadvantages of single-component organic semiconductors for high-performance organic field-effect transistors (OFETs). We show that when a solution processable organic semiconductor (6,13-bis(triisopropylsilylethynyl)pentacene, TIPS-pentacene) is blended with an insulating polymer (PS), morphological and structural characteristics of the blend films could be significantly influenced by the processing conditions like the spin coating time. Although vertical phase-separated structures (TIPS-pentacene-top/PS-bottom) were formed on the substrate regardless of the spin coating time, the spin time governed the growth mode of the TIPS-pentacene molecules that phase-separated and crystallized on the insulating polymer. Excess residual solvent in samples spun for a short duration induces a convective flow in the drying droplet, thereby leading to one-dimensional (1D) growth mode of TIPS-pentacene crystals. In contrast, after an appropriate spin-coating time, an optimum amount of the residual solvent in the film led to two-dimensional (2D) growth mode of TIPS-pentacene crystals. The 2D spherulites of TIPS-pentacene are extremely advantageous for improving the field-effect mobility of FETs compared to needle-like 1D structures, because of the high surface coverage of crystals with a unique continuous film structure. In addition, the porous structure observed in the 2D crystalline film allows gas molecules to easily penetrate into the channel region, thereby improving the gas sensing properties.

Functional status of immune cells in patients with long-lasting type 2 diabetes mellitus

Although patients with diabetes contract infectious diseases at higher frequencies, and in more severe forms, compared to non-diabetics, the underlying defects of the immune function have not been defined clearly. To address this, we designed an immune monitoring protocol and analysed the functional status of various immune cells. Peripheral blood mononuclear cells (PBMCs) were stimulated with the proper ligands and the functional reactivity of each lineage of cells was subsequently measured. Patients with type 2 diabetes mellitus (T2DM) had PBMC composition ratios comparable to healthy controls, except for a higher frequency of B cell and effector T cell fractions. The capacity of myeloid cells to secrete proinflammatory cytokines was not diminished in terms of the sensitivity and magnitude of the response. Furthermore, cytolytic activity and interferon (IFN)-γ production of natural killer (NK) cells and CD8⁺ T cells were not decreased in T2DM patients. Phenotypical maturation of dendritic cells, indicated by the up-regulation of major histocompatibility complex (MHC) proteins and co-stimulatory molecules in response to lipopolysaccharide (LPS), was slightly enhanced in T2DM patients. Finally, the functional differentiation profiles of CD4⁺ T cells did not differ between T2DM patients and the control group. These data indicate that patients with long-lasting T2DM do not have any gross functional defects in immune cells, at least in circulating monocytes, dendritic cells, NK cells and T lymphocytes.

Star-Shaped Intense Uptake of ¹³¹I on Whole Body Scans Can Reflect Good Therapeutic Effects of Low-Dose Radioactive Iodine Treatment of 1.1 GBq

BACKGROUND

After initial radioactive iodine (RAI) treatment in differentiated thyroid cancer patients, we sometimes observe a star-shaped region of intense uptake of ¹³¹I on whole body scans (WBSs), called a 'star artifact.' We evaluated the clinical implications of star artifacts on the success rate of remnant ablation and long-term prognosis.

METHODS

Total 636 patients who received ¹³¹I dose of 1.1 GBq for the initial RAI therapy and who did not show distant metastasis at the time of diagnosis were retrospectively evaluated. A negative second WBS was used for evaluating the ablation efficacy of the RAI therapy. Among them, 235 patients (36.9%) showed a star artifact on their first WBS.

RESULTS

In patients with first stimulated thyroglobulin (sTg) levels ≤2 ng/mL, patients with star artifacts had a higher rate of negative second WBS compared with those without star artifacts (77.8% vs. 63.9%, P=0.044), and showed significantly higher recurrence-free survival (P=0.043) during the median 8.0 years (range, 1.0 to 10.0) of follow-up. The 5- and 10-year recurrence rates (5YRR, 10YRR) were also significantly lower in patients with star artifacts compared with those without (0% vs. 4.9%, respectively, P=0.006 for 5YRR; 0% vs. 6.4%, respectively, P=0.005 for 10YRR). However, ablation success rate or recurrence-free survival was not different among patients whose first sTg levels >2 ng/mL regardless of star artifacts.

CONCLUSION

Therefore, star artifacts at initial RAI therapy imply a good ablation efficacy or a favorable long-term prognosis in patients with sTg levels ≤2 ng/mL.

Highly Sensitive Flexible Pressure Sensors Based on Printed Organic Transistors with Centro-Apically Self-Organized Organic Semiconductor Microstructures

A highly sensitive pressure sensor based on printed organic transistors with three-dimensionally self-organized organic semiconductor microstructures (3D OSCs) was demonstrated. A unique organic transistor with semiconductor channels positioned at the highest summit of printed cylindrical microstructures was achieved simply by printing an organic semiconductor and polymer blend on the plastic substrate without the use of additional etching or replication processes. A combination of the printed organic semiconductor microstructure and an elastomeric top-gate dielectric resulted in a highly sensitive organic field-effect transistor (FET) pressure sensor with a high pressure sensitivity of 1.07 kPa^-1 and a rapid response time of <20 ms with a high reliability over 1000 cycles. The flexibility and high performance of the 3D OSC FET pressure sensor were exploited in the successful application of our sensors to real-time monitoring of the radial artery pulse, which is useful for healthcare monitoring, and to touch sensing in the e-skin of a realistic prosthetic hand.

Changes in the clinicopathological characteristics and genetic alterations of follicular thyroid cancer

OBJECTIVE

Changes in the clinicopathological characteristics and genetic alterations of follicular thyroid cancer (FTC) over time have not been reported. Moreover, the prognostic effects of RAS and TERT promoter mutations in FTC have not been clearly elucidated. We investigated changes in the clinicopathological characteristics of patients with FTC over four decades, as well as the clinical significance of genetic mutations of FTC.

DESIGN AND METHODS

This retrospective study included 690 patients with FTC who underwent thyroidectomy between 1973 and 2015 at the Seoul National University Hospital. In 134 samples, genetic tests for N/H/KRAS and TERT promoter mutations and PAX8/PPARγ rearrangement were performed.

RESULTS

The age at diagnosis has increased (P < 0.001) in recent decades and extrathyroidal extension of the tumor has become less common (P = 0.033). Other clinicopathological characteristics and prognosis of FTC have not significantly changed. The prevalence of RAS mutations decreased (P = 0.042) over time, whereas that of TERT promoter mutations remained stable. RAS mutations were associated with distant metastasis and persistent disease, and TERT promoter mutations were associated with distant metastasis, advanced TNM stage, recurrence and disease-specific mortality. FTC patients with coexistent RAS and TERT promoter mutations showed a higher recurrence risk than those with only one mutation.

CONCLUSIONS

The age at diagnosis of FTC and the frequency of extrathyroidal extension have changed over four decades. Moreover, the prevalence of RAS mutations decreased. RAS and TERT promoter mutations may be associated with poor clinical outcomes in FTC, especially when the two mutations coexist.

Effects of Coexistent BRAFV600E and TERT Promoter Mutations on Poor Clinical Outcomes in Papillary Thyroid Cancer: A Meta-Analysis

BACKGROUND

The presence of a telomerase reverse transcriptase (TERT) promoter mutation has been suggested as a potential prognostic marker for thyroid cancer, and a synergistic association with the BRAF^V600E mutation has been demonstrated. The aim of this study was to verify the role of this genetic duet in papillary thyroid cancer (PTC).

METHODS

Studies of the association of BRAF^V600E and TERT promoter mutations with clinicopathologic features, recurrence, or PTC-related mortality were included from PubMed and Embase databases (inception to September 2016).

RESULTS

Thirteen eligible studies incorporating 4347 patients with PTC were included, and 283 (median 8.3%) of these patients had coexistent BRAF^V600E and TERT promoter mutations. The coexistence of the two mutations was far more strongly associated with high-risk clinicopathologic features than either mutation alone was, including advanced TNM stage (vs. BRAF^V600E: odds ratio [OR] = 4.19 [confidence interval (CI) 3.07-5.71]; vs. TERT: OR = 4.66 [CI 2.67-8.13]), extrathyroidal extension (vs. BRAF^V600E: OR = 3.1 [CI 2.2-4.37]; vs. TERT: OR = 5.66 [CI 3.02-10.6]), lymph node metastasis (vs. BRAF^V600E: OR = 1.59 [CI 1.16-2.17]; vs. TERT: OR = 2.03 [CI 1.22-3.38]), and distant metastasis (vs. BRAF^V600E: OR = 11.76 [CI 5.63-24.58]). The coexistence of the mutations showed the highest risk of recurrence (coexistence vs. no mutations: hazard ratio [HR] = 6.60 [CI 3.82-11.40]; BRAF^V600E vs. no mutations: HR = 1.31 [CI 0.49-3.46]; TERT vs. no mutations: HR = 3.38 [CI 0.85-13.35]). Moreover, PTC-related mortality was significantly higher with coexistent mutations than in the presence of BRAF^V600E alone (HR = 20.07 [CI 8.37-48.09]).

CONCLUSIONS

Coexistent BRAF^V600E and TERT promoter mutations have a synergistic effect on clinical outcomes in PTC, whereas each mutation alone has a modest effect. Therefore, molecular testing of BRAF^V600E and TERT promoter mutations together is useful in assessing risk stratification of PTC.

Instantaneous Pulsed-Light Cross-Linking of a Polymer Gate Dielectric for Flexible Organic Thin-Film Transistors

We report the instantaneous pulsed-light cross-linking of polymer gate dielectrics on a flexible substrate by using intensely pulsed white light (IPWL) irradiation. Irradiation with IPWL for only 1.8 s of a poly(4-vinylphenol) (PVP) thin film with the cross-linking agent poly(melamine-co-formaldehyde) (PMF) deposited on a plastic substrate was found to yield fully cross-linked PVP films. It was confirmed that the IPWL-cross-linked PVP films have smooth pinhole-free surfaces and exhibit a low leakage current density, organic solvent resistance, and good compatibility with organic semiconductor, and that they can be used as replacements for typical PVP dielectrics that are cross-linked with time and energy intensive thermal heating processes. The synchronization of the IPWL irradiation with substrate transfer was found to enable the preparation of cross-linked PVP films on large area substrates with a highly uniform capacitance. Flexible OTFT based on IPWL-cross-linked PVP dielectrics were found to exhibit good electrical performance that is comparable to that of devices with thermally cross-linked PVP dielectric, as well as excellent deformation stability even at a bending radius of 3 mm.

Macrophage Densities Correlated with CXC Chemokine Receptor 4 Expression and Related with Poor Survival in Anaplastic Thyroid Cancer

BACKGROUND

Tumor associated macrophages (TAMs) and CXC chemokine receptor 4 (CXCR4) have emerged as potential biomarkers in various human cancers. The aims of this study were to investigate the clinical characteristics of anaplastic thyroid cancer (ATC) patients according to the TAM numbers in the tumor tissue, and to evaluate the associations between CXCR4 expressions and macrophage densities in ATC tumor microenvironment.

METHODS

Total 14 ATC samples from thyroid tissue microarray were used. Immunohistochemical staining was performed using anti-CD163 and anti-CXCR4 antibodies. According to the immunoreactivity of CD163, all subjects were divided into two groups: low-CD163 (n=8) and high-CD163 (n=6) groups.

RESULTS

The mean diagnostic age was 65±7 years and the median tumor size was 4.3 cm, ranging 2.5 to 15 cm. Clinicopathological characteristics were not significantly different between low-CD163 and high-CD163 groups, while age of diagnosis was younger in high-CD163 group than that of low-CD163 group with marginal significance (56.9±5.5 years vs. 67.5±6.8 years, P=0.09). However, overall survival was significantly reduced in high-CD163 group (5.5 months [range, 1 to 10]) compared with low-CD163 groups (8.8 months [range, 6 to 121); log-rank test, P=0.0443). Moreover, high-CD163 group showed strong CXCR4 expressions in both cancer and stromal compartments, while low-CD163 group showed relatively weak, stromal-dominant CXCR4 expressions. Additionally, CD163 and CXCR4 expressions showed a strong positive correlation (γ²=0.432, P=0.013).

CONCLUSION

Increased number of TAMs showed poor overall survival in ATC, suggesting TAMs are potentially a prognostic biomarker for ATC. CXCR4 expression was significantly correlated with CD163-positive TAM densities, which suggest the possible role of CXCR4 in TAM recruitments.

Prognostic effects of TERT promoter mutations are enhanced by coexistence with BRAF or RAS mutations and strengthen the risk prediction by the ATA or TNM staging system in differentiated thyroid cancer patients

BACKGROUND

Recent reports suggest that mutations in the promoter of the gene encoding telomerase reverse transcriptase (TERT) affect thyroid cancer outcomes.

METHODS

In all, 551 patients with differentiated thyroid cancer (DTC) enrolled in this study. The median follow-up duration was 4.8 years (interquartile range, 3.4-10.6 years).

RESULTS

TERT promoter mutations were detected in 25 DTCs (4.5%): 2.8% in neither BRAF-mutated nor RAS-mutated tumors, 4.8% in BRAF-mutated tumors, and 11.3% in RAS-mutated tumors. Moreover, they were frequently observed in American Thyroid Association (ATA) high-risk and TNM stage III/IV groups (9.1% and 12.9%, respectively). The coexistence of BRAF or RAS with TERT promoter mutations increased aggressive clinicopathologic features, recurrence (hazard ratio [HR] for BRAF, 4.64; 95% confidence interval [CI], 1.42-15.18; HR for RAS, 5.36; 95% CI, 1.20-24.02), and mortality (HR for BRAF, 15.13; 95% CI, 1.55-148.23; HR for RAS, 14.75; 95% CI, 1.30-167.00), even after adjustments for the age at diagnosis and sex, although the significance was lost after additional adjustments for pathologic characteristics. Furthermore, TERT promoter mutations significantly increased the risk of both recurrence and mortality in the ATA high-risk (HR for recurrence, 5.79; 95% CI, 2.07-16.18; HR for mortality, 16.16; 95% CI, 2.10-124.15) and TNM stage III/IV groups (HR for recurrence, 3.60; 95% CI, 1.19-10.85; HR for mortality, 9.06; 95% CI, 2.09-39.26).

CONCLUSIONS

The coexistence of BRAF or RAS mutations enhanced the prognostic effects of TERT promoter mutations. Furthermore, TERT promoter mutations strengthened the predictions of mortality and recurrence by the ATA and TNM staging systems, particularly for high-risk patients with DTC. Cancer 2016;122:1370-1379. © 2016 American Cancer Society.

Sheet Size-Induced Evaporation Behaviors of Inkjet-Printed Graphene Oxide for Printed Electronics

The size of chemically modified graphene nanosheets is a critical parameter that affects their performance and applications. Here, we show that the lateral size of graphene oxide (GO) nanosheets is strongly correlated with the concentration of graphite oxide present in the suspension as graphite oxide is exfoliated by sonication. The size of the GO nanosheets increased from less than 100 nm to several micrometers as the concentration of graphite oxide in the suspension was increased up to a critical concentration. An investigation of the evaporation behavior of the GO nanosheet solution using inkjet printing revealed that the critical temperature of formation of a uniform film, T(c), was lower for the large GO nanosheets than for the small GO nanosheets. This difference was attributed to the interactions between the two-dimensional structures of GO nanosheets and the substrate as well as the interactions among the GO nanosheets. Furthermore, we fabricated organic thin film transistors (OTFTs) using line-patterned reduced GO as electrodes. The OTFTs displayed different electrical performances, depending on the graphene sheet size. We believe that our new strategy to control the size of GO nanosheets and our findings about the colloidal and electrical properties of size-controlled GO nanosheets will be very effective to fabricate graphene based printed electronics.

Intense pulsed light induced crystallization of a liquid-crystalline polymer semiconductor for efficient production of flexible thin-film transistors

The split-second crystallization of a conjugated polymer by irradiation of intense pulsed white light improved the performance of flexible thin-film transistors.

TERT Promoter Mutations and Tumor Persistence/Recurrence in Papillary Thyroid Cancer

PURPOSE

A telomerase reverse transcriptase (TERT) promoter mutation was identified in thyroid cancer. This TERT promoter mutation is thought to be a prognostic molecular marker, because its association with tumor aggressiveness, persistence/recurrence, and disease-specific mortality in papillary thyroid carcinoma (PTC) has been reported. In this study, we attempted to determine whether the impact of the TERT promoter mutation on PTC persistence/recurrence is independent of clinicopathological parameters.

MATERIALS AND METHODS

Using propensity score matching, 39 patients with PTC persistence or recurrence were matched with 35 patients without persistence or recurrence, with a similar age, sex, tumor size, multifocality, bilaterality, extrathyroidal extension, and lymph node metastasis. The TERT promoter and the BRAF V600E mutations were identified from PTC samples.

RESULTS

The TERT promoter mutation was detected in 18% of PTC patients (13/74). No significant difference in the frequency of the TERT promoter mutation was observed between the persistence/recurrence group and the non-recurrence group.

CONCLUSION

These results suggest that the prognostic implications of the TERT promoter mutation are dependent on clinicopathological parameters.

Nonvolatile Ferroelectric Memory Circuit Using Black Phosphorus Nanosheet-Based Field-Effect Transistors with P(VDF-TrFE) Polymer

Two-dimensional van der Waals (2D vdWs) materials are a class of new materials that can provide important resources for future electronics and materials sciences due to their unique physical properties. Among 2D vdWs materials, black phosphorus (BP) has exhibited significant potential for use in electronic and optoelectronic applications because of its allotropic properties, high mobility, and direct and narrow band gap. Here, we demonstrate a few-layered BP-based nonvolatile memory transistor with a poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) ferroelectric top gate insulator. Experiments showed that our BP-based ferroelectric transistors operate satisfactorily at room temperature in ambient air and exhibit a clear memory window. Unlike conventional ambipolar BP transistors, our ferroelectric transistors showed only p-type characteristics due to the carbon-fluorine (C-F) dipole effect of the P(VDF-TrFE) layer, as well as the highest linear mobility value of 1159 cm(2) V(-1) s(-1) with a 10(3) on/off current ratio. For more advanced memory applications beyond unit memory devices, we implemented two memory inverter circuits, a resistive-load inverter circuit and a complementary inverter circuit, combined with an n-type molybdenum disulfide (MoS2) nanosheet. Our memory inverter circuits displayed a clear memory window of 15 V and memory output voltage efficiency of 95%.

Influence of thyroid dysfunction on serum levels of angiopoietin-like protein 6

Angiopoietin-like protein 6 (ANGPTL6) is a novel metabolic regulator that modulates energy expenditure as well as glucose and lipid metabolism. Thyroid hormone can induce metabolic changes that are similar to those induced by ANGPTL6. Herein, we investigated whether circulating ANGPTL6 levels change according to thyroid hormone status in humans. We measured the serum levels of ANGPTL6 and metabolic parameters in 150 drug-naïve subjects with overt hyperthyroid, subclinical hyperthyroid, euthyroid, subclinical hypothyroid, or overt hypothyroid status (n=30 in each group). Serum ANGPTL6 levels were significantly higher in patients with overt hypothyroidism than in the other subjects. Women had significantly higher serum levels of ANGPTL6 than men. ANGPTL6 levels correlated positively with thyroid stimulating hormone (TSH), total cholesterol, aspartate aminotransferase, and alanine aminotransferase (ALT) and negatively with serum free thyroxine (T4) level. Multiple stepwise linear regression analysis revealed that sex, TSH, free T4, and ALT were independent predictors of serum ANGPTL6 levels. In summary, serum ANGPTL6 levels increased in patients with a hypothyroid status, and both TSH and free T4 levels are associated with ANGPLT6 levels, suggesting a possible association between thyroid function and ANGPTL6 levels. Whether the upregulated ANGPTL6 level in the hypothyroid status is primarily owing to a direct association or a compensatory mechanism remains to be determined.

Mutation Profile of Well-Differentiated Thyroid Cancer in Asians

Recent advances in molecular diagnostics have led to significant insights into the genetic basis of thyroid tumorigenesis. Among the mutations commonly seen in thyroid cancers, the vast majority are associated with the mitogen-activated protein kinase pathway. B-Raf proto-oncogene (BRAF) mutations are the most common mutations observed in papillary thyroid cancers (PTCs), followed by RET/PTC rearrangements and RAS mutations, while follicular thyroid cancers are more likely to harbor RAS mutations or PAX8/peroxisome proliferator-activated receptor γ (PPARγ) rearrangements. Beyond these more common mutations, alterations in the telomerase reverse transcriptase (TERT) promoter have recently been associated with clinicopathologic features, disease prognosis, and tumorigenesis in thyroid cancer. While the mutations underlying thyroid tumorigenesis are well known, the frequency of these mutations is strongly associated with geography, with clear differences reported between Asian and Western countries. Of particular interest is the prevalence of BRAF mutations, with Korean patients exhibiting the highest rate of BRAF-associated thyroid cancers in the world. Here, we review the prevalence of each of the most common mutations in Asian and Western countries, and identify the characteristics of well-differentiated thyroid cancer in Asians.

Abstract 2134: Standard immunohistochemistry efficiently screens for ALK rearrangements in differentiated thyroid cancer

The anaplastic lymphoma kinase (ALK) gene is frequently rearranged in various types of cancer, and is highly responsive to the target therapeutics. We developed a pipeline to detect ALK rearrangement in a large group of Korean thyroid cancer patients. We screened 474 malignant or benign thyroid tumor cases to find ALK fusion. The expression and translocation of the ALK gene were analysed by immunohistochemistry (IHC), fluorescence in situ hybridisation (FISH), and digital multiplexed gene expression (DMGE) using formalin-fixed paraffin embedded tissues. Four cases of ALK rearrangement were screened out of 474 patients by IHC, which were validated by performing FISH for 189 samples. On the other hand, DMGE analysis using Nanostring could detect three out of four IHC positive cases. Two ALK rearrangements were Striatin (STRN)-ALK fusion, identified by 5′ RACE analysis. ALK rearrangements were found exclusively in the BRAF wild type papillary carcinoma. Given the wide availability and accuracy for detecting ectopic ALK expression in the thyroid, we suggest that IHC based screening can be used as a practical method for identifying patients with ALK rearranged differentiated thyroid cancer.

Citation Format: Gahee Park, Tae Hyuk Kim, Hae-Ock Lee, Jung Ah Lim, Jae-Kyung Won, Hye Sook Min, Kyu Eun Lee, Do Joon Park, Young Joo Park, Woong-Yang Park. Standard immunohistochemistry efficiently screens for ALK rearrangements in differentiated thyroid cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2134. doi:10.1158/1538-7445.AM2015-2134

Standard immunohistochemistry efficiently screens for anaplastic lymphoma kinase rearrangements in differentiated thyroid cancer

The anaplastic lymphoma kinase (ALK) gene is frequently rearranged in various types of cancer and is highly responsive to targeted therapeutics. We developed a system to detect rearrangement of ALK in a large group of Korean thyroid cancer patients. We screened 474 malignant or benign thyroid tumor cases to identify ALK fusions. Expression and translocation of the ALK gene were analyzed by immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and digital multiplexed gene expression (DMGE) analysis in formalin-fixed paraffin-embedded tissues. Four cases of rearrangement of ALK were detected by IHC, and these cases were validated with FISH on 189 samples. On the other hand, DMGE analysis using Nanostring detected three out of four IHC-positive cases. Two rearrangements of ALK were striatin (STRN)-ALK fusions, which were identified by 5' RACE analysis. Rearrangements of ALK were found exclusively in v-raf murine sarcoma viral oncogene homolog B (BRAF) WT papillary carcinomas. Given the wide availability and accuracy of IHC for detecting ectopic expression of ALK in the thyroid, we suggest that IHC-based screening can be a practical method for identifying patients with ALK rearrangements in differentiated thyroid cancer.

Printed In-Ga-Zn-O drop-based thin-film transistors sintered using intensely pulsed white light

We developed printed IGZO TFTs by delivering droplets of a precursor solution using a picoliter fluidic dispensing system.

The Frequency and Clinical Implications of the BRAF(V600E) Mutation in Papillary Thyroid Cancer Patients in Korea Over the Past Two Decades

BACKGROUND

Over the past several decades, there has been a rapid worldwide increase in the prevalence of papillary thyroid cancer (PTC) as well as a number of changes in the clinicopathological characteristics of this disease. BRAF(V600E), which is a mutation of the proto-oncogene BRAF, has become the most frequent genetic mutation associated with PTC, particularly in Korea. Thus, the present study investigated whether the prevalence of the BRAF(V600E) mutation has increased over the past two decades in the Korean population and whether various PTC-related clinicopathological characteristics have changed.

METHODS

The present study included 2,624 patients who underwent a thyroidectomy for PTC during two preselected periods; 1995 to 2003 and 2009 to 2012. The BRAF(V600E) mutation status of each patient was confirmed using the polymerase chain reaction-restriction fragment length polymorphism method or by the direct sequencing of DNA.

RESULTS

The prevalence of the BRAF(V600E) mutation in Korean PTC patients increased from 62.2% to 73.7% (P=0.001) over the last two decades. Additionally, there was a greater degree of extrathyroidal extension (ETE) and lymph node metastasis in 2009 to 2012 patients with the BRAF(V600E) mutation and a higher frequency of thyroiditis and follicular variant-PTC in 2009 to 2012 patients with wild-type BRAF. However, only the frequency of ETE was significantly higher in 1995 to 2003 patients with the BRAF(V600E) mutation (P=0.047). Long-term recurrence rates during a 10-year median follow-up did not differ based on BRAF(V600E) mutation status.

CONCLUSION

The BRAF(V600E) mutation rate in Korean PTC patients has been persistently high (approximately 70%) over the past two decades and continues to increase. The present findings demonstrate that BRAF(V600E)-positive PTC was associated with more aggressive clinicopathological features, especially in patients who were recently diagnosed, suggesting that BRAF(V600E) mutation status may be a useful prognostic factor for PTC in patients recently diagnosed with this disease.

Few-layer black phosphorus field-effect transistors with reduced current fluctuation

We investigated the reduction of current fluctuations in few-layer black phosphorus (BP) field-effect transistors resulting from Al2O3 passivation. In order to verify the effect of Al2O3 passivation on device characteristics, measurements and analyses were conducted on thermally annealed devices before and after the passivation. More specifically, static and low-frequency noise analyses were used in monitoring the charge transport characteristics in the devices. The carrier number fluctuation (CNF) model, which is related to the charge trapping/detrapping process near the interface between the channel and gate dielectric, was employed to describe the current fluctuation phenomena. Noise reduction due to the Al2O3 passivation was expressed in terms of the reduced interface trap density values D(it) and N(it), extracted from the subthreshold slope (SS) and the CNF model, respectively. The deviations between the interface trap density values extracted using the SS value and CNF model are elucidated in terms of the role of the Schottky barrier between the few-layer BP and metal contact. Furthermore, the preservation of the Al2O3-passivated few-layer BP flakes in ambient air for two months was confirmed by identical Raman spectra.

Secular trends in the prognostic factors for papillary thyroid cancer

OBJECTIVE

With the recent increasing rates of screening for thyroid cancer, the cancers now tend to be smaller and less aggressive than those that are diagnosed when presented with symptoms, suggesting changes in the clinical validity of conventional prognostic factors for outcomes. We performed the retrospective study to identify the secular trends in the prognostic factors of thyroid cancer.

METHODS

We used medical records of 3147 patients diagnosed with papillary thyroid cancer (PTC) at the Seoul National University Hospital Thyroid Cancer Clinic between 1962 and 2009.

RESULTS

During the median 5.1-year follow-up, the overall recurrence rate was 13.3%, and male sex, tumor size, lymph node (LN) involvement, and extrathyroidal extension (ETE) were the significant prognostic factors for recurrence. Thyroid cancer-specific mortality was 1.4%, and the associated prognostic factors were older age, male sex, and LN involvement. For tumor recurrence, the hazard ratio (HR) for male sex decreased from 2.809 (95% CI, 1.497-5.269) in the pre-1989 period to 1.142 (95% CI, 0.736-1.772) in the post-1999 period. The pathologic characteristics, such as tumor size, LN involvement, and ETE, showed similar or increasing HRs over the time periods. For cancer-specific mortality, the HR for male sex decreased from 6.460 (95% CI, 1.714-24.348) in the pre-1990 period to 0.781 (95% CI, 0.083-7.379) in the post-1999 period.

CONCLUSION

The risk for poor outcomes in PTC associated with male sex decreased over time; in contrast, the risk associated with pathologic characteristics remained the same or increased over time. These trends might be associated with recent changes in the characteristics of patients with thyroid cancer.

Graphene oxide nanosheet wrapped white-emissive conjugated polymer nanoparticles

We have demonstrated the preparation of white-emissive conjugated polymer nanoparticles wrapped with graphene oxide (GO) nanosheets. Highly stable, GO-wrapped, poly(9,9-di-n-octylfluorenyl-2,7-diyl) nanoparticles (GO-PFO NPs) with diameters in the range 30-150 nm were successfully obtained by utilizing the GO nanosheets as an interface stabilizer in an emulsification process. The synthesized GO-PFO NPs exhibited unique white-emitting photoluminescence with a characteristic green-emissive broad band above 500 nm, which was distinct from the photoluminescent behavior of PFO NPs without GO. This green emission was deduced to originate from the presence of the GO nanosheet shell surrounding the PFO NPs, rather than from luminescence of GO itself or formation of keto defects in the PFO chain. PL decay analysis showed that the GO-wrapped PFO NPs had a longer luminescence lifetime in comparison to PFO NPs without GO, and highly efficient energy transfer to lower energy state induced by the GO occurred.

Split-second nanostructure control of a polymer:fullerene photoactive layer using intensely pulsed white light for highly efficient production of polymer solar cells

Intensely pulsed white light (IPWL) treatment was tested as an ultrafast, large-area processable optical technique for the control of the nanostructure of a polymeric bulk-heterojunction photoactive layer to improve the efficiencies of polymer solar cells. Only 2 s of IPWL irradiation of a polymer:fullerene photoactive layer under ambient conditions was found to enhance significantly the power conversion efficiencies of the tested polymer solar cells to values approaching that of typical devices treated with thermal annealing. Consecutive white-light pulses from the xenon lamp induce the self-organization of the polymeric donor into an ordered structure and result in the optimized phase segregation of the polymeric donor and the fullerene acceptor in the photoactive layer, which enhances the light absorption and hole mobility and results in efficient photocurrent generation. The effects of varying the pulse conditions on device performance, including the irradiation fluence, pulse duration time, and number of pulses, were systematically investigated. Finally, it was successfully demonstrated that the IPWL treatment produces flexible polymer solar cells. The proposed IPWL process is suitable for the efficient industrial roll-to-roll production of polymer solar cells.

Long-term prognosis of differentiated thyroid cancer with lung metastasis in Korea and its prognostic factors

BACKGROUND

Distant metastasis, generally to lung and bone, is rare in differentiated thyroid carcinoma (DTC) and the prognosis is still elusive. We investigated long-term outcomes of lung metastasis in DTC patients and its prognostic factors.

METHODS

A retrospective review was performed of 4572 patients who underwent surgery for DTC from 1962 to 2009 at Seoul National University Hospital. Among them, 164 patients were identified with lung metastasis and 152 patients were enrolled in the final analysis. Poor prognosis was defined as progressive disease or death.

RESULTS

Of these 152 patients, 10- and 20-year survival rates were 85.0% and 71.0%, respectively. No evidence of disease, stable disease, progressive disease, and death was identified in 22.4%, 28.3%, 35.5%, and 13.8%, respectively, after 11 years of median follow-up (range 2-41 years). Older age at diagnosis (≥45 years), primary tumor size ≥2 cm, follicular thyroid cancer, metastasis diagnosed after initial evaluation or (131)I remnant ablation (late metastasis), multiple metastases other than lung, (131)I nonavidity, and the presence of macronodules (≥1 cm) were more frequent in poor prognoses. Cox proportional hazard ratio for progression-free survival showed that (131)I nonavidity was the only independent predictive factor for poor prognosis.

CONCLUSIONS

The prognosis of lung metastasis from DTC in Korea within this study was favorable. (131)I nonavidity, observed more frequently in late metastasis, was the only independent factor predicting poor prognosis.

Predictive factors of malignancy in thyroid nodules with a cytological diagnosis of follicular neoplasm

In cases of follicular neoplasm identified by thyroid fine-needle aspiration (FNA), surgery is required to achieve a precise diagnosis. We investigated potential clinical factors for the preoperative prediction of malignancy in thyroid nodules with a cytological diagnosis of follicular neoplasm. We retrospectively reviewed the data of 97 patients who were diagnosed with follicular neoplasm by FNA and had undergone surgery at the Korea Cancer Center Hospital between April 2010 and April 2012. Age, sex, laboratory data (such as thyroid-stimulating hormone, free T4, thyroglobulin (Tg), and Tg antibody), and ultrasonographic findings were reviewed from the electronic medical records. Of 97 patients, 50 (51.5 %) were diagnosed with benign nodules, 16 (16.5 %) with follicular thyroid carcinoma (FTC), and 31 (32.0 %) with papillary thyroid carcinoma (PTC). In comparison with the features of benign nodules, FTC presented with a large nodule size, high serum Tg level, isoechogenicity, calcifications, and peripheral halo, whereas PTC exhibited traits similar to those of benign nodules, except for high serum Tg level and the presence of calcifications on ultrasonography. Therefore, a high serum Tg level (≥75 ng/mL) and calcification were the only significant predictive factors for malignancy in case of follicular neoplasm (p < 0.01). Serum Tg levels and the presence of calcification on ultrasonography are important clinical features to predict malignancy in thyroid nodules with cytological diagnosis of follicular neoplasm.

Changes in the clinicopathological characteristics and outcomes of thyroid cancer in Korea over the past four decades

BACKGROUND

Thyroid cancer has increased globally, with a prominent increase in small, papillary thyroid cancers (PTC). The Korean population has a high iodine intake, high prevalence of BRAF V600E mutations, and family histories of thyroid cancer. We examined the clinicopathological characteristics and outcomes of thyroid cancers in Korean patients over four decades.

METHODS

The medical records of 4500 thyroid cancer patients, between 1962 and 2009 at a single center, including 3147 PTC patients, were reviewed.

RESULTS

The mean age of the patients was 46.8±13.2 years; women accounted for 82.9% of the patients, and the median follow-up duration was 4.8 years (mean 7.0±5.8 years, range 1-43 years). The number of patients visiting the clinic increased from 411 during 1962-1990 to 2900 during 2000-2009. Age at diagnosis increased from 39.6±12.9 to 48.6±12.4 years. The male to female ratio increased from 1:6 to 1:4.5. The proportion of small (<1 cm) tumors increased from 6.1% to 43.1%, and the proportion of cancers with lymph node (LN) involvement or extrathyroidal extension (ETE) decreased from 76.4% to 44.4% and from 65.5% to 54.8% respectively. Although there were decreases in the proportion of LN involvement and ETE, these decreasing rates were not proportional to the expected rates based on the decreased proportion of large tumors. The overall recurrence and mortality rates were 13.3% and 1.4%. The five-year recurrence rate significantly decreased (from 11% to 5.9%), and the five-year mortality also improved (from 1.5% to 0.2%).

CONCLUSIONS

The incidence of thyroid cancer has rapidly increased, with a decrease in tumors of large size, LN involvement, and ETE, although the decreasing rates of LN involvement and ETE were not as prominent as decreasing rates of large size tumors. The mortality and recurrence rates have also decreased. Future long-term follow-up of patients diagnosed in the most recent decade is needed to confirm the prognostic characteristics of Korean PTC patients.

Associations between thyroid hormone levels and regional fat accumulation in euthyroid men

OBJECTIVE

Body adiposity, especially ectopic fat accumulation, has a range of metabolic and cardiovascular effects. This study aimed to investigate whether thyroid function is associated with various regional fat quantities in euthyroid subjects.

METHODS

A total of 100 euthyroid men (free triiodothyronine (fT3), 4.77±1.21 pg/ml; free thyroxine (fT4), 1.38±0.21 ng/dl; and TSH, 2.09±0.91 μIU/ml) were enrolled in this cross-sectional study. We measured accumulated regional fat using 64-slice multi-detector computed tomography. Multiple linear regression analysis was used to determine whether accumulated fat in each region was associated with clinical parameters after adjusting for age.

RESULTS

FT3 was inversely correlated with BMI (R=0.232, P=0.029) and LDL cholesterol level (R=0.277, P=0.019). FT4 was inversely correlated with waist circumference (R=0.350, P=0.008) and BMI (R=0.355, P0.001). In multiple linear regression analysis, fT3 and fT4 levels were significantly associated with pericardial fat volume (fT3: B=-0.079, 95% CI -0.142 to -0.017, P=0.013; fT4: B=-0.411, 95% CI -0.780 to -0.042, P=0.030) in euthyroid men, independent of age. FT3 level was inversely associated with intramuscular fat area (B=-0.059, 95% CI -0.106 to -0.011, P=0.016) and hepatic fat quantity (B=-0.237, 95% CI -0.441 to -0.033, P=0.024) in euthyroid men, independent of age.

CONCLUSIONS

In euthyroid men, low levels of fT3 and fT4 were significantly associated with increased pericardial fat volume and BMI.

Porous polyimide membranes prepared by wet phase inversion for use in low dielectric applications

A wet phase inversion process of polyamic acid (PAA) allowed fabrication of a porous membrane of polyimide (PI) with the combination of a low dielectric constant (1.7) and reasonable mechanical properties (Tensile strain: 8.04%, toughness: 3.4 MJ/m³, tensile stress: 39.17 MPa, and young modulus: 1.13 GPa), with further thermal imidization process of PAA. PAA was simply synthesized from purified pyromellitic dianhydride (PMDA) and 4,4-oxydianiline (ODA) in two different reaction solvents such as γ-butyrolactone (GBL) and N-methyl-2-pyrrolidinone (NMP), which produce M_w/PDI of 630,000/1.45 and 280,000/2.0, respectively. The porous PAA membrane was fabricated by the wet phase inversion process based on a solvent/non-solvent system via tailored composition between GBL and NMP. The porosity of PI, indicative of a low electric constant, decreased with increasing concentration of GBL, which was caused by sponge-like formation. However, due to interplay between the low electric constant (structural formation) and the mechanical properties, GBL was employed for further exploration, using toluene and acetone vs. DI-water as a coagulation media. Non-solvents influenced determination of the PAA membrane size and porosity. With this approach, insight into the interplay between dielectric properties and mechanical properties will inform a wide range of potential low-k material applications.

Thyroglobulin in washout fluid from lymph node fine-needle aspiration biopsy in papillary thyroid cancer: large-scale validation of the cutoff value to determine malignancy and evaluation of discrepant results

CONTEXT

There are still some controversies regarding the cutoff value and the influential factors of thyroglobulin (Tg) concentration in washout fluid from fine-needle aspiration (FNA) biopsy (FNA-Tg) on cervical lymph nodes (LNs) in patients with papillary thyroid cancer (PTC).

OBJECTIVE

Our aims were to validate the cutoff value of FNA-Tg in diagnosing malignant LNs on a large scale and to investigate the influential factors that could result in the discrepancy between the final diagnosis and FNA-Tg.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a retrospective cohort study based on hospital records with 528 cases of FNA-Tg measurement from 419 PTC patients.

MAIN OUTCOME MEASURE

The cutoff value of FNA-Tg was obtained from receiver operating characteristic analysis with final diagnosis. Binary logistic regression analysis was performed to investigate the influential factors.

RESULTS

In the final diagnosis, 190 LNs were malignant, and 338 LNs were benign. The median FNA-Tg was 521.2 (3676.8) ng/mL in malignant LNs, and 0.1 (0.2) ng/mL in benign LNs. The optimal cutoff value of FNA-Tg in distinguishing malignant LNs from benign LNs was 1.0 ng/mL (sensitivity, 93.2%; specificity, 95.9%) in all cases. Combining FNA-Tg and FNA cytology showed superior diagnostic power (sensitivity, 98.4%; specificity, 94.4%) when compared with diagnostic strategy using either FNA cytology or FNA-Tg alone. FNA-Tg, serum TSH, and serum Tg were higher in nonthyroidectomized patients than in thyroidectomized patients (P < .001, respectively). FNA-Tg was correlated with serum TSH and Tg levels (P < .001, respectively), and binary logistic regression analysis showed that serum TSH suppression and serum Tg presence independently affected the diagnosis made by FNA-Tg.

CONCLUSIONS

Our results validated 1.0 ng/mL of FNA-Tg as a cutoff value for diagnosing LN metastasis of PTC and suggested that serum TSH suppression and serum Tg presence should be considered in diagnosing LN malignancy with FNA-Tg in PTC patients.