c-Axis Aligned 3 nm Thick In2O3 Crystal Using New Liquid DBADMIn Precursor for Highly Scaled FET Beyond the Mobility-Stability Trade-off.

Oxide semiconductors (OS) are attractive materials for memory and logic device applications owing to their low off-current, high field effect mobility, and superior large-area uniformity. Recently, successful research has reported the high field-effect mobility (µFE) of crystalline OS channel transistors (above 50 cm2 V-1 s-1). However, the memory and logic device application presents challenges in mobility and stability trade-offs. Here, we propose a method for achieving high-mobility and high-stability by lowering the grain boundary effect. A DBADMIn precursor was synthesized to deposit highly c-axis-aligned C(222) crystalline 3 nm thick In2O3 films. In this study, the 250 °C deposited 3 nm thick In2O3 channel transistor exhibited high µFE of 41.12 cm2 V-1 s-1, Vth of -0.50 V, and SS of 150 mV decade-1 with superior stability of 0.16 V positive shift during PBTS at 100 °C, 3 MV cm-1 stress conditions for 3 h.

Large-Area Growth of Ferroelectric 2D γ-In2 Se3 Semiconductor by Spray Pyrolysis for Next-Generation Memory.

In2 Se3 , 2D ferroelectric-semiconductor, is a promising candidate for next-generation memory device because of its outstanding electrical properties. However, the large-area manufacturing of In2 Se3 is still a big challenge. In this work, spray pyrolysis technique is introduced for the growth of large-area In2 Se3 thin film. A polycrystalline γ-In2 Se3 layer can be grown on 15 cm × 15 cm glasss at the substrate temperature of 275 °C. The In2 Se3 ferroelectric-semiconductor field effect transistor (FeS-FET) on glass substrate demonstrates a large hysteresis window of 40.3 V at the ±40 V of gate voltage sweep and excellent uniformity. The FeS-FET exhibits an electron field effect mobility of 0.97 cm2 V-1 s-1 and an on/off current ratio of >107 in the transfer curves. The memory behavior of the large-area, In2 Se3 FeS-FETs for next-generation memory is demonstrated.

Type-II Red Phosphorus: Wavy Packing of Twisted Pentagonal Tubes.

Elemental phosphorus exhibits fascinating structural varieties and versatile properties. The unique nature of phosphorus bonds can lead to the formation of extremely complex structures, and detailed structural information on some phosphorus polymorphs is yet to be investigated. In this study, we investigated an unidentified crystalline phase of phosphorus, type-II red phosphorus (RP), by combining state-of-the-art structural characterization techniques. Electron diffraction tomography, atomic-resolution scanning transmission electron microscopy (STEM), powder X-ray diffraction, and Raman spectroscopy were concurrently used to elucidate the hidden structural motifs and their packing in type-II RP. Electron diffraction tomography, performed using individual crystalline nanowires, was used to identify a triclinic unit cell with volume of 5330 Å3 , which is the largest unit cell for elemental phosphorus crystals up to now and contains approximately 250 phosphorus atoms. Atomic-resolution STEM imaging, which was performed along different crystal-zone axes, confirmed that the twisted wavy tubular motif is the basic building block of type-II RP. Our study discovered and presented a new variation of building blocks in phosphorus, and it provides insights to clarify the complexities observed in phosphorus as well as other relevant systems.

Thermally Activated Defect Engineering for Highly Stable and Uniform ALD-Amorphous IGZO TFTs with High-Temperature Compatibility.

Highly stable IGZO thin-film transistors derived from atomic layer deposition are crucial for the semiconductor industry. However, unavoidable defect generation during high-temperature annealing results in abnormal positive bias temperature stress (PBTS). Herein, we propose a defect engineering method by controlling the gate insulator (GI) deposition temperature. Applying a GI deposition temperature of 400 °C to the In0.52Ga0.18Zn0.30O active layer effectively suppresses defects even after 600 °C annealing, preserving the amorphous phase of IGZO. The device exhibits a threshold voltage (VTH) of 0.05 V, a field-effect mobility of 27.6 cm2/Vs, a subthreshold swing of 61 mV/decade, and a hysteresis voltage of 0.01 V, demonstrating highly reliable PBTS and negative bias temperature stress. A power-law fit of the PBTS stability under 2 MV/cm of gate field stress and 120 °C of temperature stress predicts a VTH shift of -0.01 V after 10 years. Moreover, the proposed method ensures reliable uniformity over a large 4 in. area.

Selectively Nitrogen Doped ALD-IGZO TFTs with Extremely High Mobility and Reliability.

Achieving high mobility and reliability in atomic layer deposition (ALD)-based IGZO thin-film transistors (TFTs) with an amorphous phase is vital for practical applications in relevant fields. Here, we suggest a method to effectively increase stability while maintaining high mobility by employing the selective application of nitrous oxide plasma reactant during plasma-enhanced ALD (PEALD) at 200 °C process temperature. The nitrogen-doping mechanism is highly dependent on the intrinsic carbon impurities or nature of each cation, as demonstrated by a combination of theoretical and experimental research. The Ga2O3 subgap states are especially dependent on plasma reactants. Based on these insights, we can obtain high-performance indium-rich PEALD-IGZO TFTs (threshold voltage: -0.47 V; field-effect mobility: 106.5 cm2/(V s); subthreshold swing: 113.5 mV/decade; hysteresis: 0.05 V). In addition, the device shows minimal threshold voltage shifts of +0.45 and -0.10 V under harsh positive/negative bias temperature stress environments (field stress: ±2 MV/cm; temperature stress: 95 °C) after 10000 s.

Temperature Dependence of Excitonic Auger Recombination in Excitonic-Complex-Free Monolayer WS2 by Considering Auger Broadening and Generation Efficiency.

Monolayer transition metal dichalcogenides (TMDs) have been extensively studied for their optoelectronic properties and applications. However, even at moderate exciton densities, their light-emitting capability is severely limited by Auger-type exciton-exciton annihilation (EEA). Previous work on EEA used oversimplified models in the presence of excitonic complexes, resulting in seriously underestimated values for the Auger coefficient. In this work, we transferred monolayer WS2 on a gold substrate with hBN encapsulation, where excitons persist as the main species at 3-300 K via metal proximity. We numerically solved the rate equation for excitons to accurately determine the Auger coefficient as a function of temperature by considering laser pulse width and spatially inhomogeneous exciton distribution. We found that the Auger coefficient consists of temperature-dependent and independent terms, consistent with a theoretical model for direct and exchange processes, respectively. We believe that our results provide a guide for enhancing the luminescence quantum yield of TMDs.

In vivo photoacoustic monitoring of vasoconstriction induced by acute hyperglycemia.

Postprandial hyperglycemia, blood glucose spikes, induces endothelial dysfunction, increasing cardiovascular risks. Endothelial dysfunction leads to vasoconstriction, and observation of this phenomenon is important for understanding acute hyperglycemia. However, high-resolution imaging of microvessels during acute hyperglycemia has not been fully developed. Here, we demonstrate that photoacoustic microscopy can noninvasively monitor morphological changes in blood vessels of live animals' extremities when blood glucose rises rapidly. As blood glucose level rose from 100 to 400 mg/dL following intraperitoneal glucose injection, heart/breath rate, and body temperature remained constant, but arterioles constricted by approximately -5.7 ± 1.1% within 20 min, and gradually recovered for another 40 min. In contrast, venular diameters remained within about 0.6 ± 1.5% during arteriolar constriction. Our results experimentally and statistically demonstrate that acute hyperglycemia produces transitory vasoconstriction in arterioles, with an opposite trend of change in blood glucose. These findings could help understanding vascular glucose homeostasis and the relationship between diabetes and cardiovascular diseases.

Design of a Current Sensing System with TIA Gain of 160 dBΩ and Input-Referred Noise of 1.8 pArms for Biosensor.

This paper proposes a high-gain low-noise current signal detection system for biosensors. When the biomaterial is attached to the biosensor, the current flowing through the bias voltage is changed so that the biomaterial can be sensed. A resistive feedback transimpedance amplifier (TIA) is used for the biosensor requiring a bias voltage. Current changes in the biosensor can be checked by plotting the current value of the biosensor in real time on the self-made graphical user interface (GUI). Even if the bias voltage changes, the input voltage of the analog to digital converter (ADC) does not change, so it is designed to plot the current of the biosensor accurately and stably. In particular, for multi-biosensors with an array structure, a method of automatically calibrating the current between biosensors by controlling the gate bias voltage of the biosensors is proposed. Input-referred noise is reduced using a high-gain TIA and chopper technique. The proposed circuit achieves 1.8 pArms input-referred noise with a gain of 160 dBΩ and is implemented in a TSMC 130 nm CMOS process. The chip area is 2.3 mm2, and the power consumption of the current sensing system is 12 mW.

The next hype in social media advertising: Examining virtual influencers' brand endorsement effectiveness.

Virtual influencers are gaining prominence as a way of attracting people's attention on social media, but limited research has been conducted on this subject. In this research, we explore the effects of human-like virtual influencers (HVIs) vs. anime-like virtual influencers (AVIs) and sponsorship disclosure on message credibility perception and message attitudes. Conducted with a 2 (virtual influencer type: HVI vs. AVI) x 2 (sponsorship disclosure: absent vs. present) between-subjects experiment, our findings suggest that HVI endorsements produce greater perception of message credibility and message attitudes than AVI endorsements, but the superior effect of HVIs (vs. AVIs) vanishes when sponsorship is disclosed. The results also show that message credibility plays a significant mediating role only when sponsorship is not disclosed. We believe our research offers interesting insights to both researchers and practitioners on the topic of virtual influencers.

In vivo quantitative photoacoustic monitoring of corticosteroid-induced vasoconstriction.

Significance: Corticosteroids-commonly prescribed medications for skin diseases-inhibit the secretion of vasodilators, such as prostaglandin, thereby exerting anti-inflammatory action by constricting capillaries in the dermis. The effectiveness of corticosteroids is determined by the degree of vasoconstriction followed by skin whitening, namely, the blanching effect. However, the current method of observing the blanching effect indirectly evaluates the effects of corticosteroids. Aim: In this study, we employed optical-resolution photoacoustic (PA) microscopy (OR-PAM) to directly visualize the blood vessels and quantitatively evaluate vasoconstriction. Approach: Using OR-PAM, the vascular density in mice skin was monitored for 60 min after performing each experimental procedure for four groups, and the vasoconstriction was quantified. Volumetric PA data were segmented into the papillary dermis, reticular dermis, and hypodermis based on the vascular characteristics obtained through OR-PAM. The vasoconstrictive effect of each skin layer was quantified according to the dermatological treatment method. Results: In the case of corticosteroid topical application, vasoconstriction was observed in the papillary ( 56.4 ± 10.9 % ) and reticular ( 45.1 ± 4.71 % ) dermis. For corticosteroid subcutaneous injection, constriction was observed solely in the reticular ( 49.5 ± 9.35 % ) dermis. In contrast, no vasoconstrictions were observed with nonsteroidal topical application. Conclusions: Our results indicate that OR-PAM can quantitatively monitor the vasoconstriction induced by corticosteroids, thereby validating OR-PAMs potential as a practical evaluation tool for predicting the effectiveness of corticosteroids in dermatology.

Negative Valley Polarization of the Intralayer Exciton via One-Step Growth of H-Type Heterobilayer WS2/MoS2.

Vertical type II van der Waals heterobilayers of transition metal dichalcogenides (TMDs) have attracted wide attention due to their distinctive features mostly arising from the emergence of intriguing electronic structures that include moiré-related phenomena. Owing to strong spin-orbit coupling under a noncentrosymmetric environment, TMD heterobilayers host nonequivalent +K and -K valleys of contrasting Berry curvatures, which can be optically controlled by the helicity of optical excitation. The corresponding valley selection rules are well established by not only intralayer excitons but also interlayer excitons. Quite intriguingly, here, we experimentally demonstrate that unusual valley switching can be achieved using the lowest-lying intralayer excitons in H-type heterobilayer WS2/MoS2 prepared by one-step growth. This TMD combination provides an ideal case for interlayer coupling with an almost perfect lattice match, thereby also in the momentum space between +K and -K valleys in the H-type heterostructure. The underlying valley-switching mechanism can be understood by bright-to-dark conversion of initially created electrons in the valley of WS2, followed by interlayer charge transfer to the opposite valley in MoS2. Our suggested model is also confirmed by the absence of valley switching when the lowest-lying excitons in MoS2 are directly generated in the heterobilayer. In contrast to the H-type case, we show that no valley switching is observed from R-type heterobilayers prepared by the same method, where interlayer charge transfer does not occur between the opposite valleys. We compare the case with the series of valley polarization data from other heterobilayer combinations obtained under different excitation energies and temperatures. Our valley switching mechanism can be utilized for valley manipulation by controlling the excitation photon energy together with the photon helicity in valleytronic devices derived from H-type TMD heterobilayers.

Investigation of phenyllactic acid as a potent tyrosinase inhibitor produced by probiotics.

Melanogenesis is responsible for skin pigmentation and the enzymatic browning of foods. Tyrosinases play a major role in melanin synthesis, and many attempts have been made to identify new natural tyrosinase inhibitors, but few have sought to do in microbes. Postbiotics are bioactive compounds produced by the metabolism of probiotics and have been reported to be safe and effective. In this study, we evaluated the tyrosinase inhibitory effects of culture supernatants of probiotics and discovered novel bacterial metabolites that can be used as a potent tyrosinase inhibitor based on metabolomics. Cultures of Bifidobacterium bifidum IDCC 4201 and Lactiplantibacillus plantarum IDCC 3501 showed effective anti-tyrosinase, reduced melanin synthesis, and altered protein expression associated with the melanogenesis pathway. Comparative metabolomics analyses conducted by GC-MS identified metabolites commonly produced by B. bifidum and L. plantarum. Of eight selected metabolites, phenyllactic acid exhibited significant tyrosinase-inhibitory activity. Our findings suggest that applications of probiotic culture supernatants containing high amounts of phenyllactic acid have potential use as anti-melanogenesis agents in food and medicines.

Single-Port Transaxillary Robotic Modified Radical Neck Dissection (STAR-RND): Initial Experiences.

OBJECTIVES: This study aimed to demonstrate the usefulness of single-port transaxillary robotic modified radical neck dissection (STAR-RND) for metastatic thyroid cancer, and its potential to make small and invisible surgical wounds possible compared to open modified radical neck dissection. METHODS: Between January 2020 and July 2021, 30 thyroid cancer patients who underwent lateral neck dissection surgery with the da Vinci SP at Yonsei University Health System (Seoul, Korea) were studied. RESULTS: All 30 patients, diagnosed with papillary thyroid cancer were women. The average operating time was 293.80 ± 36.58 (min), and the average postoperative hospital stay was 4.77 ± 0.57 (days). All patients were discharged after the expected number of hospitalization days without major complications. CONCLUSION: STAR-RND is technically feasible and safe with a short length of the incision. To our knowledge, this is the first report on the use of a single-port robotic system for modified radical neck dissection. LEVEL OF EVIDENCE BY USING 2011 OCEBM: 4 Laryngoscope, 133:709-714, 2023.

Opto-ultrasound biosensor for wearable and mobile devices: realization with a transparent ultrasound transducer.

Mobile and wearable healthcare electronics are widely used for measuring bio-signals using various fusion sensors that employ photoplethysmograms, cameras, microphones, ultrasound (US) sensors, and accelerometers. However, the consumer demand for small form factors has significantly increased as the integration of multiple sensors is difficult in small mobile or wearable devices. This study proposes two novel opto-US sensors, namely (1) a wearable photoplethysmography (PPG)-US device and (2) a PPG sensor built-in mobile smartphone with a US sensor, seamlessly integrated using a transparent ultrasound transducer (TUT). The TUT exhibits a center frequency of 6 MHz with a 50% bandwidth and 82% optical transparency in visible and near-infrared regions. We developed an integrated wearable PPG-US device to demonstrate its feasibility and coupled the TUT sensor with a smartphone. We measured the heart rates optically and acoustically in human subjects and quantified the oxygen saturation optically by passing light through the TUT. The proposed proof-of-concept is a novel sensor fusion for mobile and wearable devices that require a small form factor and aim to improve digital healthcare. The results of this study can form the basis for innovative developments in sensor-based high-tech industrial applications, such as automobiles, robots, and drones, in addition to healthcare applications.

A voting-based ensemble feature network for semiconductor wafer defect classification.

Semiconductor wafer defects severely affect product development. In order to reduce the occurrence of defects, it is necessary to identify why they occur, and it can be inferred by analyzing the patterns of defects. Automatic defect classification (ADC) is used to analyze large amounts of samples. ADC can reduce human resource requirements for defect inspection and improve inspection quality. Although several ADC systems have been developed to identify and classify wafer surfaces, the conventional ML-based ADC methods use numerous image recognition features for defect classification and tend to be costly, inefficient, and time-consuming. Here, an ADC technique based on a deep ensemble feature framework (DEFF) is proposed that classifies different kinds of wafer surface damage automatically. DEFF has an ensemble feature network and the final decision network layer. The feature network learns features using multiple pre-trained convolutional neural network (CNN) models representing wafer defects and the ensemble features are computed by concatenating these features. The decision network layer decides the classification labels using the ensemble features. The classification performance is further enhanced by using a voting-based ensemble learning strategy in combination with the deep ensemble features. We show the efficacy of the proposed strategy using the real-world data from SK Hynix.

Metformin ameliorates olanzapine-induced disturbances in POMC neuron number, axonal projection, and hypothalamic leptin resistance.

Antipsychotics have been widely accepted as a treatment of choice for psychiatric illnesses such as schizophrenia. While atypical antipsychotics such as aripiprazole are not associated with obesity and diabetes, olanzapine is still widely used based on the anticipation that it is more effective in treating severe schizophrenia than aripiprazole, despite its metabolic side effects. To address metabolic problems, metformin is widely prescribed. Hypothalamic proopiomelanocortin (POMC) neurons have been identified as the main regulator of metabolism and energy expenditure. Although the relation between POMC neurons and metabolic disorders is well established, little is known about the effects of olanzapine and metformin on hypothalamic POMC neurons. In the present study, we investigated the effect of olanzapine and metformin on the hypothalamic POMC neurons in female mice. Olanzapine administration for 5 days significantly decreased Pomc mRNA expression, POMC neuron numbers, POMC projections, and induced leptin resistance before the onset of obesity. It was also observed that coadministration of metformin with olanzapine not only increased POMC neuron numbers and projections but also improved the leptin response of POMC neurons in the olanzapine-treated female mice. These findings suggest that olanzapine-induced hypothalamic POMC neuron abnormality and leptin resistance, which can be ameliorated by metformin administration, are the possible causes of subsequent hyperphagia. [BMB Reports 2022; 55(6): 293-298].

A Low-Power Analog Processor-in-Memory-Based Convolutional Neural Network for Biosensor Applications.

This paper presents an on-chip implementation of an analog processor-in-memory (PIM)-based convolutional neural network (CNN) in a biosensor. The operator was designed with low power to implement CNN as an on-chip device on the biosensor, which consists of plates of 32 × 32 material. In this paper, 10T SRAM-based analog PIM, which performs multiple and average (MAV) operations with multiplication and accumulation (MAC), is used as a filter to implement CNN at low power. PIM proceeds with MAV operations, with feature extraction as a filter, using an analog method. To prepare the input feature, an input matrix is formed by scanning a 32 × 32 biosensor based on a digital controller operating at 32 MHz frequency. Memory reuse techniques were applied to the analog SRAM filter, which is the core of low power implementation, and in order to accurately grasp the MAC operational efficiency and classification, we modeled and trained numerous input features based on biosignal data, confirming the classification. When the learned weight data was input, 19 mW of power was consumed during analog-based MAC operation. The implementation showed an energy efficiency of 5.38 TOPS/W and was differentiated through the implementation of 8 bits of high resolution in the 180 nm CMOS process.

Manipulation of resonance orders and absorbing materials for structural colors in transmission with improved color purity.

We present an improved color purity of additive transmissive structural color filters by controlling a resonance order and by inserting a highly absorbing material. The proposed structure consists of a single metal sandwiched by two transparent dielectric media serving as a cavity to minimize the ohmic loss in the metal mirrors, which is distinctly different from a conventional Fabry-Perot (FP) cavity that is in general designed to have two metal mirrors. Low reflections at an air-dielectric interface cause a quality-factor of a resonance to be reduced, causing a degraded color purity, which can be improved by employing a 1st order resonance that exhibits a narrower bandwidth than a fundamental FP resonant mode (0th order). For a red color with the improved purity, introducing an ultrathin absorbing layer in the middle of a top cavity enables the 1st resonance to be trivially influenced while selectively suppressing a 2nd order resonance appearing at the shorter wavelength region. Moreover, angle-insensitive performances up to 60° are attained by utilizing a cavity material with high index of refraction. Besides, the fabrication of the structural coloring devices involves a few deposition steps, thus rendering the approach suitable for applications over the large area. The described concept could be applied to diverse applications, such as colored solar panels, sensors, imaging devices, and decorations.

Parathyroid venous sampling for the preoperative localisation of parathyroid adenoma in patients with primary hyperparathyroidism.

Preoperative localisation studies are essential for parathyroidectomy in patients with primary hyperparathyroidism. If the location of abnormal parathyroid glands cannot be identified through non-invasive studies, parathyroid venous sampling (PVS) may be employed. In this study, we evaluated the utility of preoperative PVS in parathyroid surgery. Patients with primary hyperparathyroidism who underwent preoperative PVS at Severance Hospital between January 2015 and June 2020 were identified. Patients for whom the results of non-invasive imaging studies were inconsistent or negative underwent PVS. The results of PVS were compared with operative findings and pathologic results. For 14 patients, the results of preoperative ultrasonography and 99mTc-sestamibi single-photon emission computed tomography (SPECT) were negative; for 20 patients, either the result of only one test was positive, or the results of the two tests were inconsistent. With respect to the lateralisation of diseased adenoma, the results of PVS and pathological examination were inconsistent only for one patient in either group (total: 2/34 patients). This study showed that PVS could be used effectively for preoperative localisation in patients with primary hyperparathyroidism in whom the location of diseased parathyroid glands cannot be determined through non-invasive image studies.

Linear and nonlinear optical properties of transfer ribonucleic acid (tRNA) thin solid films.

We successfully obtained transfer ribonucleic acid (tRNA) thin solid films (TSFs) using an aqueous solution precursor in an optimized deposition process. By varying the concentration of RNA and deposition process parameters, uniform solid layers of solid RNA with a thickness of 30 to 46 nm were fabricated consistently. Linear absorptions of RNA TSFs on quartz substrates were experimentally investigated in a wide spectral range covering UV-VIS-NIR to find high transparency for λ > 350 nm. We analyzed the linear refractive indices, n(λ) of tRNA TSFs on silicon substrates by using an ellipsometer in the 400 to 900 nm spectral range to find a linear correlation with the tRNA concentration in the aqueous solution. The thermo-optic coefficient (dn/dT) of the films was also measured to be in a range -4.21 × 10-4 to -5.81 × 10-4 °C-1 at 40 to 90 °C. We furthermore characterized nonlinear refractive index and nonlinear absorption of tRNA TSFs on quartz using a Z-scan method with a femtosecond laser at λ = 795 nm, which showed high potential as an efficient nonlinear optical material in the IR spectral range.