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Context The 2015 American Thyroid Association guidelines proposed thyroid lobectomy as an acceptable option for 1- to 4-cm papillary thyroid cancers (PTC) without extrathyroidal extension (ETE) or lymph node (LN) metastasis. However, high-risk features are often detected postoperatively, even in tumors that are considered low risk on preoperative workup. A continued evaluation is necessary to determine the optimal treatment strategies. Objective We examined the frequency of preoperatively and postoperatively detected high-risk features in 2- to 4-cm PTCs to assess the appropriate surgical extent. Methods All patients who underwent a thyroid surgery between 2015 and 2020 with a final diagnosis of 2- to 4-cm PTC were selected. Demographics, preoperative findings, perioperative course, and surgical pathology were retrospectively analyzed. Results Of the entire study cohort (N = 424), 244 (57.5%) patients had at least 1 of the following high-risk features: gross ETE (18.6%), distant metastasis (1.2%), >3 LN involvement with extranodal extension (24.8%), any LN > 3 cm (0.5%), positive margin (13.2%), TERT mutation (2.6%), vascular invasion (10.8%), cN1 disease (28.5%), and > 5 LN involvement (30.4%). Two hundred patients had neither ETE nor LN metastasis on preoperative imaging, but 62/200 (31.0%) were found to have at least 1 of the aforementioned high-risk features on final pathology. Preoperative imaging had sensitivities of 75.9% and 44.4% for detecting gross ETE and LN metastasis, respectively. Conclusion A significant portion of patients with 2- to 4-cm PTCs, including those who preoperatively met the criteria for lobectomy, were found to have high-risk features on final pathology. Careful patient selection and appropriate counseling are necessary when considering lobectomy for tumors greater than 2 cm.

Robotic thyroid surgeries in children are gaining popularity due to cosmetic advantages, but most previous studies include patients of school-age or older. We hereby introduce our case of a 5-year-old patient with Graves' disease to show key differences and similarities between pediatric and adult bilateral axillo-breast approach (BABA) robotic thyroidectomies. Despite the small body, no additional working space was needed and the flap creation was performed as similarly done in adults. The anatomy was not much different, except that the parathyroid tissues were easily identified due to low body fat, and the prominent thymus covered most of the level VI area. The patient did not experience postoperative complications such as hypoparathyroidism or vocal cord palsy. Postoperative wounds showed excellent results with minimal scars. BABA robotic thyroidectomy can be performed safely in pediatric patients and may be considered an alternative option for conventional open thyroidectomy in children.

In the present study, the effect of the addition of 0.5 at% Al on the thermal stability and thermoplastic forming ability of Ti35Zr15Ni40Cu10 metallic glass have been investigated. The results of non-isothermal and isothermal DSC experiments show that the addition of Al stabilizes the supercooled liquid. The activation energies obtained by non-isothermal (isothermal) DSC experiments are 389 (540) and 417 (558) KJ/mol for Ti35Zr15Ni40Cu10 and Ti35Zr14.5Ni40Cu10Al0.5, respectively. Based on the higher thermal stability of the supercooled liquid, the thermoplastic forming ability is improved with the addition of Al. The largest filling depths for Ti35Zr15Ni40Cu10 and Ti35Zr14.5Ni40Cu10Al0.5 are ~ 6.1 μm and ~ 7.5 μm, respectively. Besides, the parameters of Fmod for the two metallic glasses has been calculated to compare the thermoplastic forming ability. The Fmod parameters are 6.65 × 10–12 Pa−1 and 1.8 × 10–11 Pa−1 in Ti35Zr15Ni40Cu10 and Ti35Zr14.5Ni40Cu10Al0.5, respectively.

A thermoelectric coated grain nanocomposite CuInTe2/SnTe with eco-friendly elements was synthesized. The nanocomposite contains a coating layer of CuInTe2 and SnO2 at the grain boundaries of the SnTe matrix. The coating layer was synthesized using the cation exchange process considering the hard soft acid base (HSAB) concept, the solubility product, and crystal structure. The CuInTe2 coating layer blocks the low energy carriers of the composite resulting in 40% enhancement of the Seebeck coefficient due to energy filtering. The coherent phonon scattering by the coating layer of CuInTe2 effectively reduces the lattice thermal conductivity to almost the minimum theoretical limit. The thermoelectric figure of merit (zT) for the CuInTe2/SnTe nanocomposite was as high as 1.68 at 823 K, which is significantly higher than that of bulk SnTe in the mid-temperature range. The average zT from 373 K to 823 K for the nanocomposite was 0.76, which is promising for utilization in industrial application.

Semiconductor sensors equipped with Pd catalysts are promising candidates as low-powered and miniaturized surveillance devices that are used to detect flammable hydrogen (H2) gas. However, the foll...

Mutations in the telomerase reverse transcriptase (TERT) promoter have been reported as a convincing prognostic factor in papillary thyroid carcinomas (PTCs). We aimed to investigate the frequency of TERT promoter mutations in patients with thyroid cancer and identify the clinicopathological factors associated with them in PTCs.A total of 1086 consecutive cases of thyroid cancer composed of mostly PTCs were included in this study. TERT promoter and BRAF mutations were detected by pyrosequencing and their associations with clinicopathological features of tumour were analyzed.TERT promoter mutations were observed in 1.9% of PTCs, 6.7% of follicular thyroid carcinomas, 8.3% of Hurthle cell carcinomas and 25.0% of poorly differentiated thyroid carcinomas and in a single case of anaplastic thyroid carcinoma. In PTCs, aggressive clinicopathological features, higher stage and BRAF V600E mutation were all found to be associated with TERT promoter mutations. Distant metastasis and disease recurrence were more frequent in TERT promoter-mutated PTCs. In multivariate analysis, age ≥55 years, tall cell variant, mitoses ≥3/10 high-power fields, tumour necrosis, and gross extrathyroidal extension (ETE) were identified as independent factors associated with TERT promoter mutations in PTCs.This study revealed a relatively low frequency of TERT promoter mutations in Korean patients with PTC. Certain clinicopathological features including old age, tall cell variant, increased mitoses, tumour necrosis and gross ETE were found to be indicative of TERT promoter mutations in PTCs, suggesting that mutational analysis in a particular group of PTCs can be effective in regions with low mutation rates.

Lateral neck lymph node dissection (LND) along with total thyroidectomy is the standard treatment for thyroid cancer patients with metastases to the lateral neck lymph nodes. In general, lateral neck LND removes lymph nodes located at levels II to V ipsilateral to the thyroid cancer and preserves the spinal accessory nerve, internal jugular vein, and sternomastoid muscle during surgery. This video article was written to introduce the robotic bilateral axillo-breast approach for lateral neck LND and to describe the surgical method.

Ti–Zr–Ni–Cu metallic glass attracts an attention as a precursor of superelastic alloy that can be deformed into nm scale complex shapes. However, since the thermal stability of Ti–Zr–Ni–Cu metallic glass in the supercooled liquid region is quite low, application of thermoplastic forming is limited. Therefore, in the present study, the effect of Sn addition on thermoplastic forming ability of Ti–Zr–Ni–Cu metallic glass has been investigated. Sn containing (Ti35Zr15Ni35Cu15)99Sn1 metallic glass exhibits longer incubation time before onset of crystallization than Ti35Zr15Ni35Cu15 metallic glass, resulting in significant improvement of thermoplastic forming ability. The crystallization behavior changes from three-dimensional growth of saturated nuclei to three-dimensional growth with constant nucleation rate with the addition of Sn. The overall activation energy for crystallization of (Ti35Zr15Ni35Cu15)99Sn1 metallic glass is higher than that of Ti35Zr15Ni35Cu15 metallic glass, indicating that the thermal stability of metallic glass is improved by addition of Sn. Because nuclei are continuously generated during the crystallization in (Ti35Zr15Ni35Cu15)99Sn1, the average grain size is much smaller than that in Ti35Zr15Ni35Cu15.

In thermoelectric energy conversions, thermal conductivity reduction is essential for enhancing thermoelectric performance while maintaining a high power factor. Herein, we propose an approach based on coated-grain structures to effectively reduce the thermal conductivity to a much greater degree when compared to that done by conventional nanodot nanocomposite. By incorporating CdTe coated layers on the surface of SnTe grains, the thermal conductivity is as low as 1.16 W/m-K at 929 K, resulting in a thermoelectric figure of merit, i.e., zT, of 1.90. According to our developed theory, phonons scatter coherently due to the phase lag between phonons passing through and around the coated grain. Such scattering is induced by the acoustic impedance mismatch between the coated layer and the grain, resulting in a gigantic phonon-scattering cross section. The phonon-scattering cross section of the coated grains is several orders of magnitude larger than that of the nanodots with the same impurity concentration. Th...

The glass forming ability (GFA), crystallization behavior and subsequent superelastic property after crystallization in Ti50-xZrxNi35Cu15 (x = 5, 10, 15, 20 at%) alloys have been investigated with an aim to develop glassy alloy precursor for shape memory alloy having both high glass forming ability and superior superelastic property. The addition of Zr is effective in improving the GFA exhibiting a critical thickness larger than 100 μm by increasing both liquid stability and resistance to crystallization. The glassy Ti50-xZrxNi35Cu15 alloys are polymorphically crystallized into B2 structure. With increasing Zr content, the grain size after crystallization decreases significantly by accelerated nucleation process. Thus, the stability of austenite increases, resulting in the decrease of Ms. The critical stress for slip deformation gradually increases with alloying Zr up to 15 at%, improving the superelastic recovery. The Ti35Zr15Ni35Cu15 alloy exhibits the highest remnant depth ratio value of 7.2%. By contrast, the superelasticity is significantly deteriorated in the Ti30Zr20Ni35Cu15 nanocrystalline alloy due to the difficulty in stress-induced martensitic transformation which is caused by extremely small grain size and irregular morphology of grain boundary. Considering both glass forming ability and superelastic property, the Ti35Zr15Ni35Cu15 alloy is confirmed to be the most suitable alloy satisfying wide supercooled liquid region (∼40 K), large maximum thickness for amorphous alloy formation (∼100 μ m) and excellent superelasticity after crystallization.

In this study, the effects of inserting mica into bulk silicon for thermoelectric use on the alloying, nanosize, and spacer effects that are mainly used to suppress thermal conductivity are examined. Results revealed that nanocrystallinity as well as the extremely high doping amount of antimony in the grains drastically enhance the power factor. Dislocations or vacancies can be induced at the nanoscopic level by performing multiple heat treatments and by inserting spacer materials at the bulk level, which in turn can inhibit the heat transport in high thermally conductive materials. Furthermore, a record and reliable figure-of-merit of ∼0.6 at 1173 K is obtained for mica-inserted SiSb0.02, in addition to reduced thermal conductivity (∼6.5 W/m-K). These observations open avenues for silicon and can further lead to the formation of intermetallic, half-Heusler, and other chalcogenide materials.

The effect of quenching temperature on local atomic structure of Al85Ni5Co2Y8 metallic glass has been investigated in the present study. With increasing quenching temperature from 1273 K to 1573 K, the amount of medium range order (MRO) tends to decrease, while the structural unit size remains almost constant. The higher amount of MRO leads to movement of the crystallization nose of time-temperature-transformation (TTT) curve to a longer time scale by raising the viscosity of the liquid. On the other hand, quenched-in nuclei are present in the samples with higher quenching temperature, since the probability of intersecting the crystallization nose during cooling becomes higher with increasing quenching temperature. As a result, typical two types of as-quenched microstructure can be obtained, i.e. fully amorphous structure with higher amount of MRO and that with embedded quenched-in nuclei as well as relatively lower amount of MRO. The sample quenched at 1273 K without quenched-in nuclei exhibits the most fragile behavior, indicating that the fragility can be affected by the quenching temperature as well as the alloy composition in Al-based metallic glass.

The alloying effect of Cu on thermal and mechanical behavior in Ni50-xTi35Zr15Cux (x = 0, 3, 5, 10, 15 at.%) shape memory alloys has been systematically investigated in the present study. The addition of Cu changes the lattice parameters and expands the unit cell volume of B2 austenite and B19 ' martensite. With alloying Cu, the temperature for austenite ↔ martensite transformation tends to decrease, and the transformation from B2 austenite to B19 ' martensite occurs in a single step mode. The decrease of transformation temperature with alloying Cu is attributed to the chemical stabilization of B2 (destabilization B19 ' ) which is reflected by the decrease of the transformation enthalpy. The stabilization of B2 comes along with the increase of valence electron concentration and non-basal shear modulus resisting to transformation into B19 ' . While, the destabilization of B19 ' structure is represented by the increase of monoclinic angle. When compared to the ternary Ni49.5Ti50.5-xZrx (x = 0, 3, 5, 10, 15, 18, 20 at. %) and Ni50-xTi50Cux (x = 0, 2.5, 5, 7.5, 10 at. %) alloys, the stabilization of B2 (destabilization B19 ' ) is more pronounced in the Ni Ti Zr Cu alloys investigated in the present study. Due to the change of thermal and structural properties with alloying Cu, the temperature dependence of stress for inducing martensitic transformation gradually decreases and the superelastic window is enlarged. As a result, the superelastic recovery is enhanced with alloying Cu.

As promising photo-absorbing materials for photovoltaics, organic–inorganic hybrid perovskite materials such as methylammonium lead iodide and formamidinium lead iodide, have attracted lots of attention from many researchers. Among the various factors to be considered for high power conversion efficiency (PCE) in perovskite solar cells (PSCs), increasing the grain size of perovskite is most important. However, it is difficult to obtain a highly crystalline perovskite film with large grain size by using the conventional hot-plate annealing method because heat is transferred unidirectionally from the bottom to the top. In this work, we presented radiative thermal annealing (RTA) to improve the structural and electrical properties of perovskite films. Owing to the omnidirectional heat transfer, swift and uniform nuclei formation was possible within the perovskite film. An average grain size of 500 nm was obtained, which is 5 times larger than that of the perovskite film annealed on a hot-plate. This perovskite film led to an enhancement of photovoltaic performance of PSCs. Both short-circuit current density and PCE of the PSCs prepared by RTA were improved by 10%, compared to those of PSCs prepared by hot-plate annealing.

Organic–inorganic hybrid perovskite solar cells (PSCs) have attracted considerable attention due to their superior power conversion efficiency (PCE), which has recently exceeded 22%. However, some issues remain regarding their use in real-life environments, with the most pressing matter being their long-term stability under humid conditions. Hybrid perovskites are naturally vulnerable to water molecules, which can induce the decomposition of perovskite photoactive chemicals such as MAPbI3 and FAPbI3. Therefore, to achieve commercial-level long-term PSC stability, the adsorption and infiltration of water into the perovskite films must be minimized. Herein, it is demonstrated that polydimethylsiloxane (PDMS) introduced simultaneously during perovskite spin-coating is highly beneficial to passivate the perovskite grains and adjacent grain boundaries (GBs). This not only promotes the formation of lead oxide (PbO) bonds that prevent a water–perovskite reaction, but also contributes to reducing the Pb defect density related to trap-assisted recombination. The photovoltaic performance of the prepared PDMS-passivated PSC is notably enhanced compared to a reference PSC (without PDMS), and surprisingly, more than 90% of the initial PCE (∼15%) is sustained after laboratory storage for 5000 h under 70% relative humidity. These results will pave the way for developing commercial perovskite optoelectronic devices.

A 6-bit 2.5-GS/s $8\times $ dynamic interpolating flash analog-to-digital converter (ADC) with an offset calibration technique for interpolated voltage-to-time converters (VTCs) is presented for high-speed applications. The dynamic-amplifier-structured VTC enables linear zero-crossing (ZX) interpolation in the time domain with an interpolation factor of 8, which reduces the number of front-end VTCs to one-sixth the original structure. The reduced number of VTCs lowers the power consumption, load capacitance to the track-and-holder (T/H), and overhead of VTC offset calibration. The sequential slope-matching offset calibration scheme is proposed not only for VTC offset but also for interpolated ZX accuracy. The prototype 6-bit 2.5-GS/s flash ADC was implemented in a 65-nm CMOS process and occupies a 0.12 mm2 chip area, including offset calibration circuitry. The measured differential non-linearity (DNL) and integral non-linearity (INL) after offset calibration are 0.68 and 0.65 LSB, respectively. With a 1.23 GHz input, the measured signal-to-noise and distortion ratio (SNDR) and spurious-free dynamic range (SFDR) are 33.84 and 45.07 dB, respectively, with power consumption of 7.5 mW under a supply voltage of 0.85 V. The prototype ADC achieves a figure of merit (FoM) of 74.7 fJ/conversion step at 2.5 GS/s.

The low-temperature processability of molecular ferroelectric (FE) crystals makes them a potential alternative for perovskite oxide-based ferroelectric thin films. Quinuclidinium perrhenate (HQReO4) is one such molecular FE crystal that exhibits ferroelectricity when crystallized in an intermediate temperature phase (ITP). However, bulk HQReO4 crystals exhibit ferroelectricity only for a narrow temperature window (22 K), above and below which the polar phase transforms to a non-FE phase. The FE phase or ITP of HQReO4 should be stabilized in a much wider temperature range for practical applications. Here, to stabilize the FE phase (ITP) in a wider temperature range, highly oriented thin films of HQReO4 were prepared using a simple solution process. A slow evaporation method was adapted for drying the HQReO4 thin films to control the morphology and the temperature window. The temperature window of the intermediate temperature FE phase was successfully widened up to 35 K by merely varying the film drying temperature between 333 and 353 K. The strategy of stabilizing the FE phase in a wider temperature range can be adapted to other molecular FE materials to realize flexible electronic devices.

In this review, we summarize the recent efforts on manipulating phonon transport in solids by using specific techniques that modify their phonon thermal conductivity (i.e., specific heat, phonon group velocity, and mean free path) and phonon thermal conductance (i.e., transmission probability and density of states). The strategies discussed for tuning thermal conductivity are as follows: large unit cell approach and liquid-like conduction for maneuvering specific heat; rattler, mini-bandgap, and phonon confinement for manipulating phonon group velocity; nanoparticles, nanosized grains, coated grains, alloy (isotope) scattering, selection rules in phonon dispersion, Gruneisen parameter, lone-pair electronics, dynamic disorder, and local static distortion for restricting mean free path. We have also included the discussion on tuning phonon thermal conductance, as thermal conduction can be viewed as a transmission process. Additionally, phonon filtering, ballistic transport, and waveguiding are discussed to alter density of states and transmission probability. We hope this review can bring meaningful insights to the researchers in the field of phonon transport in solids.