Prior conscious experience modulates the impact of audiovisual temporal correspondence on unconscious visual processing.

Conscious visual experiences are enriched by concurrent auditory information, implying audiovisual interactions. In the present study, we investigated how prior conscious experience of auditory and visual information influences the subsequent audiovisual temporal integration under the surface of awareness. We used continuous flash suppression (CFS) to render perceptually invisible a ball-shaped object constantly moving and bouncing inside a square frame window. To examine whether audiovisual temporal correspondence facilitates the ball stimulus to enter awareness, the visual motion was accompanied by click sounds temporally congruent or incongruent with the bounces of the ball. In Experiment 1, where no prior experience of the audiovisual events was given, we found no significant impact of audiovisual correspondence on visual detection time. However, when the temporally congruent or incongruent bounce-sound relations were consciously experienced prior to CFS in Experiment 2, congruent sounds yielded faster detection time compared to incongruent sounds during CFS. In addition, in Experiment 3, explicit processing of the incongruent bounce-sound relation prior to CFS slowed down detection time when the ball bounces became later congruent with sounds during CFS. These findings suggest that audiovisual temporal integration may take place outside of visual awareness though its potency is modulated by previous conscious experiences of the audiovisual events. The results are discussed in light of the framework of multisensory causal inference.

Rhythmic motor behavior explains individual differences in grammar skills in adults.

A growing body of literature has reported the relationship between music and language, particularly between individual differences in perceptual rhythm skill and grammar competency in children. Here, we investigated whether motoric aspects of rhythm processing-as measured by rhythmic finger tapping tasks-also explain the rhythm-grammar connection in 150 healthy young adults. We found that all expressive rhythm skills (spontaneous, synchronized, and continued tapping) along with rhythm discrimination skill significantly predicted receptive grammar skills on either auditory sentence comprehension or grammaticality well-formedness judgment (e.g., singular/plural, past/present), even after controlling for verbal working memory and music experience. Among these, synchronized tapping and rhythm discrimination explained unique variance of sentence comprehension and grammaticality judgment, respectively, indicating differential associations between different rhythm and grammar skills. Together, we demonstrate that even simple and repetitive motor behavior can account for seemingly high-order grammar skills in the adult population, suggesting that the sensorimotor system continue to support syntactic operations.

Neural consequences of binaural beat stimulation on auditory sentence comprehension: an EEG study.

A growing literature has shown that binaural beat (BB)-generated by dichotic presentation of slightly mismatched pure tones-improves cognition. We recently found that BB stimulation of either beta (18 Hz) or gamma (40 Hz) frequencies enhanced auditory sentence comprehension. Here, we used electroencephalography (EEG) to characterize neural oscillations pertaining to the enhanced linguistic operations following BB stimulation. Sixty healthy young adults were randomly assigned to one of three listening groups: 18-Hz BB, 40-Hz BB, or pure-tone baseline, all embedded in music. After listening to the sound for 10 min (stimulation phase), participants underwent an auditory sentence comprehension task involving spoken sentences that contained either an object or subject relative clause (task phase). During the stimulation phase, 18-Hz BB yielded increased EEG power in a beta frequency range, while 40-Hz BB did not. During the task phase, only the 18-Hz BB resulted in significantly higher accuracy and faster response times compared with the baseline, especially on syntactically more complex object-relative sentences. The behavioral improvement by 18-Hz BB was accompanied by attenuated beta power difference between object- and subject-relative sentences. Altogether, our findings demonstrate beta oscillations as a neural correlate of improved syntactic operation following BB stimulation.

LAVA HyperSense and deep-learning reconstruction for near-isotropic (3D) enhanced magnetic resonance enterography in patients with Crohn's disease: utility in noise reduction and image quality improvement.

PURPOSE: This study aimed to compare near-isotropic contrast-enhanced T1-weighted (CE-T1W) magnetic resonance enterography (MRE) images reconstructed with vendor-supplied deep-learning reconstruction (DLR) with those reconstructed conventionally in terms of image quality. METHODS: A total of 35 patients who underwent MRE for Crohn's disease between August 2021 and February 2022 were included in this retrospective study. The enteric phase CE-T1W MRE images of each patient were reconstructed with conventional reconstruction and no image filter (original), with conventional reconstruction and image filter (filtered), and with a prototype version of AIRTM Recon DL 3D (DLR), which were then reformatted into the axial plane to generate six image sets per patient. Two radiologists independently assessed the images for overall image quality, contrast, sharpness, presence of motion artifacts, blurring, and synthetic appearance for qualitative analysis, and the signal-to-noise ratio (SNR) was measured for quantitative analysis. RESULTS: The mean scores of the DLR image set with respect to overall image quality, contrast, sharpness, motion artifacts, and blurring in the coronal and axial images were significantly superior to those of both the filtered and original images (P < 0.001). However, the DLR images showed a significantly more synthetic appearance than the other two images (P < 0.05). There was no statistically significant difference in all scores between the original and filtered images (P > 0.05). In the quantitative analysis, the SNR was significantly increased in the order of original, filtered, and DLR images (P < 0.001). CONCLUSION: Using DLR for near-isotropic CE-T1W MRE improved the image quality and increased the SNR.

Beta and gamma binaural beats enhance auditory sentence comprehension.

Binaural beats-an auditory illusion produced when two pure tones of slightly different frequencies are dichotically presented-have been shown to modulate various cognitive and psychological states. Here, we investigated the effects of binaural beat stimulation on auditory sentence processing that required interpretation of syntactic relations (Experiment 1) or an evaluation of syntactic well formedness (Experiment 2) with a large cohort of healthy young adults (N = 200). In both experiments, participants performed a language task after listening to one of four sounds (i.e., between-subject design): theta (7 Hz), beta (18 Hz), and gamma (40 Hz) binaural beats embedded in music, or the music only (baseline). In Experiment 1, 100 participants indicated the gender of a noun linked to a transitive action verb in spoken sentences containing either a subject or object-relative center-embedded clause. We found that both beta and gamma binaural beats yielded better performance, compared to the baseline, especially for syntactically more complex object-relative sentences. To determine if the binaural beat effect can be generalized to another type of syntactic analysis, we conducted Experiment 2 in which another 100 participants indicated whether or not there was a grammatical error in spoken sentences. However, none of the binaural beats yielded better performance for this task indicating that the benefit of beta and gamma binaural beats may be specific to the interpretation of syntactic relations. Together, we demonstrate, for the first time, the positive impact of binaural beats on auditory language comprehension. Both theoretical and practical implications are discussed.

Closed loop obstruction of small bowel: CT signs predicting successful non-surgical treatment.

PURPOSE: To clarify the computed tomography (CT) findings related to successful conservative treatments in patients with closed-loop small bowel obstruction (CL-SBO) without evidence of bowel strangulation. METHODS: Sixty-four patients (71 CT scans) diagnosed with CL-SBO by CT and received initial conservative treatments from May 2010 to August 2020 were retrospectively included. Two blinded radiologists reviewed the CT findings, including the transition zone (number, distance, and location), maximum bowel diameter, mesenteric haziness, mesenteric fluid, increased unenhanced bowel wall attenuation, decreased bowel wall enhancement, small bowel feces sign, whirl sign, bowel wall thickening, ascites, and degree of obstruction. The findings of the success and failure groups of conservative treatment were compared. Interobserver agreement was assessed for all findings. RESULTS: Among the 71 cases, conservative treatments were successful in 42 cases (59 %) but failed in 29 cases (41 %). In multivariable analyses, the distance between the transition zones (>1 cm) and low-degree obstruction were independently associated with successful conservative treatments, with odds ratios of 6.23 and 3.52, respectively. The combination of these two CT findings exhibited a specificity of 89.7 % with a positive likelihood ratio of 3.01. Interobserver agreement of the degree of obstruction and the distance between the transition zones was almost perfect (ĸ = 0.814 and 0.914, respectively). CONCLUSIONS: The distance between the transition zones (>1 cm) and low-grade obstruction are independent CT predictors of successful conservative treatments in CL-SBO patients. Initial conservative treatments are recommended for patients with both CT findings.

Sensorimotor and working memory systems jointly support development of perceptual rhythm processing.

We studied the role of sensorimotor and working memory systems in supporting development of perceptual rhythm processing with 119 participants aged 7-12 years. Children were assessed for their abilities in sensorimotor synchronization (SMS; beat tapping), auditory working memory (AWM; digit span), and rhythm discrimination (RD; same/different judgment on a pair of musical rhythm sequences). Multiple regression analysis revealed that children's RD performance was independently predicted by higher beat tapping consistency and greater digit span score, with all other demographic variables (age, sex, socioeconomic status, music training) controlled. The association between RD and SMS was more robust in the slower tempos (60 and 100 beats-per-minute (BPM)) than faster ones (120 and 180 BPM). Critically, the relation of SMS to RD was moderated by age in that RD performance was predicted by beat tapping consistency in younger children (age: 7-9 years), but not in older children (age: 10-12 years). AWM was the only predictor of RD in older children. Together, the current findings demonstrate that the sensorimotor and working memory systems jointly support RD processing during middle-to-late childhood and that the degree of association between the two systems and perceptual rhythm processing is shifted before entering into early adolescence.

A Novel Interposer Channel Structure with Vertical Tabbed Vias to Reduce Far-End Crosstalk for Next-Generation High-Bandwidth Memory.

In this paper, we propose and analyze a novel interposer channel structure with vertical tabbed vias to achieve high-speed signaling and low-power consumption in high-bandwidth memory (HBM). An analytical model of the self- and mutual capacitance of the proposed interposer channel is suggested and verified based on a 3D electromagnetic (EM) simulation. We thoroughly analyzed the electrical characteristics of the novel interposer channel considering various design parameters, such as the height and pitch of the vertical tabbed via and the gap of the vertical channel. Based on the frequency-dependent lumped circuit resistance, inductance, and capacitance, we analyzed the channel characteristics of the proposed interposer channel. In terms of impedance, insertion loss, and far-end crosstalk, we analyzed how much the proposed interposer channel improved the signal integrity characteristics compared to a conventional structure consisting of micro-strip and strip lines together. Compared to the conventional worst case, which is the strip line, the eye-width, the eye-height, and eye-jitter of the proposed interposer channel were improved by 17.6%, 29%, and 9.56%, respectively, at 8 Gbps. The proposed interposer channel can reduce dynamic power consumption by about 28% compared with the conventional interposer channel by minimizing the self-capacitance of the off-chip channel.

3D Neural Network Composed of Neurospheroid and Bionanohybrid on Microelectrode Array to Realize the Spatial Input Signal Recognition in Neurospheroid.

There have been several studies for demonstration of 2D neural network using living cells or organic/inorganic molecules, but to date, there is no report of development of a 3D neural network in vitro. Based on developed bionanohybrid composed of protein, DNA, molybdenum disulfide nanoparticles, and peptides for controlling electrophysiological states of living cells, here, the in vitro 3D neural network composed of the bionanohybrid, 3D neurospheroid and the microelectrode array (MEA) is developed. After production of the 3D neurospheroid derived from human neural stem cells, the bionanohybrid developed on the MEA successfully semi-penetrates the neurites of the 3D neurospheroid and forms the 3D neural network. The developed 3D neural network successfully exhibited the electrophysiological output signals of the 3D neurospheroid by transmitting the input signal applied by the bionanohybrid. Moreover, by using the selectively immobilized bionanohybrid on the MEA, the spatial input signal recognition in the neurospheroid of 3D neural network is realized for the first time. This newly developed in vitro 3D neural network provides a promising strategy to be applied in brain-on-a-chip, brain disease-related drug efficacy evaluation, bioelectronics, and bioelectronic medicine.

Bionanohybrid composed of metalloprotein/DNA/MoS2/peptides to control the intracellular redox states of living cells and its applicability as a cell-based biomemory device.

The development of cell-based bioelectronic devices largely depends on the direct control of intracellular redox states. However, most related studies have focused on the accurate measurement of electrical signals from living cells, whereas direct intracellular state control remains largely unexplored. Here, we developed a biocompatible transmembranal bionanohybrid structure composed of a recombinant metalloprotein, DNA, molybdenum disulfide nanoparticles (MoS2), and peptides to control intracellular redox states, which can be used as a cell-based biomemory device. Using the capacitance of MoS2 located inside the cell, the bionanohybrid controled the intracellular redox states of living cells by recording and extracting intracellular charges, which inturn was achieved by activating (writing) and deactivating (erasing) the cells. As a proof of concept, cell-based biomemory functions including writing, reading, and erasing were successfully demonstrated and confirmed via electrochemical methods and patch-clamp analyses, resulting in the development of the first in vitro cell-based biomemory device. This newly developed bionanohybrid provides a novel approach to control cellular redox states for cell-based bioelectronic applications, and can be applicable in a wide range of biological fields including bioelectronic medicine and intracellular redox status regulation.

Image Quality and Diagnostic Performance of Accelerated Shoulder MRI With Deep Learning-Based Reconstruction.

BACKGROUND. Shoulder MRI using standard multiplanar sequences requires long scan times. Accelerated sequences have tradeoffs in noise and resolution. Deep learning-based reconstruction (DLR) may allow reduced scan time with preserved image quality. OBJECTIVE. The purpose of this study was to compare standard shoulder MRI sequences and accelerated sequences without and with DLR in terms of image quality and diagnostic performance. METHODS. This retrospective study included 105 patients (45 men, 60 women; mean age, 57.6 ± 10.9 [SD] years) who underwent a total of 110 3-T shoulder MRI examinations. Examinations included standard sequences (scan time, 9 minutes 23 seconds) and accelerated sequences (3 minutes 5 seconds; 67% reduction), both including fast spin-echo sequences in three planes. Standard sequences were reconstructed using the conventional pipeline; accelerated sequences were reconstructed using both the conventional pipeline and a commercially available DLR pipeline. Two radiologists independently assessed three image sets (standard sequence, accelerated sequence without DLR, and accelerated sequence with DLR) for subjective image quality and artifacts using 4-point scales (4 = highest quality) and identified pathologies of the subscapularis tendon, supraspinatus-infraspinatus tendon, long head of the biceps brachii tendon, and glenoid labrum. Interobserver agreement and agreement between image sets for the evaluated pathologies were assessed using weighted kappa statistics. In 27 patients who underwent arthroscopy, diagnostic performance was calculated using arthroscopic findings as a reference standard. RESULTS. Mean subjective image quality scores for readers 1 and 2 were 10.6 ± 1.2 and 10.5 ± 1.4 for the standard sequence, 8.1 ± 1.3 and 7.2 ± 1.1 for the accelerated sequence without DLR, and 10.7 ± 1.2 and 10.5 ± 1.6 for the accelerated sequence with DLR. Mean artifact scores for readers 1 and 2 were 9.3 ± 1.2 and 10.0 ± 1.0 for the standard sequence, 7.3 ± 1.3 and 9.1 ± 0.8 for the accelerated sequence without DLR, and 9.4 ± 1.2 and 9.8 ± 0.8 for the accelerated sequence with DLR. Interobserver agreement ranged from kappa of 0.813-0.951 except for accelerated sequence without DLR for the supraspinatus-infraspinatus tendon (κ = 0.673). Agreement between image sets ranged from kappa of 0.809-0.957 except for reader 1 for supraspinatus-infraspinatus tendon (κ = 0.663-0.700). Accuracy, sensitivity, and specificity for tears of the four structures were not different (p > .05) among image sets. CONCLUSION. Accelerated sequences with DLR provide 67% scan time reduction with similar subjective image quality, artifacts, and diagnostic performance to standard sequences. CLINICAL IMPACT. Accelerated sequences with DLR may provide an alternative to standard sequences for clinical shoulder MRI.

Cross-Modal Correspondence Between Speech Sound and Visual Shape Influencing Perceptual Representation of Shape: the Role of Articulation and Pitch.

Cross-modal correspondence is the tendency to systematically map stimulus features across sensory modalities. The current study explored cross-modal correspondence between speech sound and shape (Experiment 1), and whether such association can influence shape representation (Experiment 2). For the purpose of closely examining the role of the two factors - articulation and pitch - combined in speech acoustics, we generated two sets of 25 vowel stimuli - pitch-varying and pitch-constant sets. Both sets were generated by manipulating articulation - frontness and height of the tongue body's positions - but differed in terms of whether pitch varied among the sounds within the same set. In Experiment 1, participants made a forced choice between a round and a spiky shape to indicate the shape better associated with each sound. Results showed that shape choice was modulated according to both articulation and pitch, and we therefore concluded that both factors play significant roles in sound-shape correspondence. In Experiment 2, participants reported their subjective experience of shape accompanied by vowel sounds by adjusting an ambiguous shape in the response display. We found that sound-shape correspondence exerts an effect on shape representation by modulating audiovisual interaction, but only in the case of pitch-varying sounds. Therefore, pitch information within vowel acoustics plays the leading role in sound-shape correspondence influencing shape representation. Taken together, our results suggest the importance of teasing apart the roles of articulation and pitch for understanding sound-shape correspondence.

Extraction of higher-order nonlinear electronic response in solids using high harmonic generation.

Nonlinear susceptibilities are key to ultrafast lightwave driven optoelectronics, allowing petahertz scaling manipulation of the signal. Recent experiments retrieved a 3rd order nonlinear susceptibility by comparing the nonlinear response induced by a strong laser field to a linear response induced by the otherwise identical weak field. The highly nonlinear nature of high harmonic generation (HHG) has the potential to extract even higher order nonlinear susceptibility terms. However, up till now, such characterization has been elusive due to a lack of direct correspondence between high harmonics and nonlinear susceptibilities. Here, we demonstrate a regime where such correspondence can be clearly made, extracting nonlinear susceptibilities (7th, 9th, and 11th) from sapphire of the same order as the measured high harmonics. The extracted high order susceptibilities show angular-resolved periodicities arising from variation in the band structure with crystal orientation. Our results open a door to multi-channel signal processing, controlled by laser polarization.

Flexible electrochemical glucose biosensor based on GOx/gold/MoS2/gold nanofilm on the polymer electrode.

The need for flexible biosensors has increased because of their potential applications for point-of-care diagnosis and wearable biosensors. However, flexible biosensors have low sensitivity due to the flexibility of the electrode, and their fabrication involves complex processes. To overcome these limitations, a flexible electrochemical enzyme biosensor was developed in this study by immobilizing an enzyme on the flexible polymer electrode modified with a gold/MoS2/gold nanofilm. The fabrication process involved sputter deposition of gold, spin coating of MoS2, and sputter deposition of gold on the flexible polymer electrode (commercially available Kapton® polyimide film). The flexible glucose biosensor was made by immobilization of glucose oxidase on a flexible electrode by using a chemical linker. The detection limit for glucose was estimated to be 10 nM, which indicates more sensitivity as compared with a previously reported flexible glucose sensor. This sensitivity is due to the facilitation of electron transfer by MoS2. The flexure extension of this biosensor was estimated at 3.48 mm, which is much higher than that of the rigid sensor using a gold-coated silicon electrode (0.09 mm), according to measurements with a micro-fatigue tester. The proposed flexible biosensor composed of the enzyme/gold/MoS2/gold nanofilm on the polymer electrode can be used as a flexible sensing platform for developing wearable biosensing systems because of its high sensitivity, high flexibility, and simple fabrication process.

Individual differences in continuous flash suppression: Potency and linkages to binocular rivalry dynamics.

Binocular rivalry (BR) and continuous flash suppression (CFS) are compelling psychophysical phenomena involving interocular suppression. Using an individual differences approach we assessed whether interocular suppression induced by CFS is predictable in potency from characteristics of BR that are plausibly governed by interocular inhibition. We found large individual differences in BR dynamics and, in addition, in the strength of CFS as gauged by the incidence and durations of breakthroughs in CFS during an extended viewing periods. CFS's potency waned with repeated trials, but stable individual differences persisted despite these mean shifts. We also discovered large individual differences in the strength of the post-CFS shift in BR dominance produced by interocular suppression. While CFS breakthroughs were significantly negatively correlated with shifts in BR dominance after CFS, there were no significant associations between individual differences in alternation rate during pre-CFS binocular rivalry and either breakthroughs during CFS or post-CFS dominance shifts. Bayesian hypothesis tests and highest posterior density intervals confirmed the weak association between these two forms of interocular suppression. Thus, our findings suggest that the substantial individual differences in BR dynamics and CFS effectiveness are modestly related but not entirely mediated by one common neural substrate.

A new class of constitutively active super-enhancers is associated with fast recovery of 3D chromatin loops.

BACKGROUND: Super-enhancers or stretch enhancers are clusters of active enhancers that often coordinate cell-type specific gene regulation during development and differentiation. In addition, the enrichment of disease-associated single nucleotide polymorphism in super-enhancers indicates their critical function in disease-specific gene regulation. However, little is known about the function of super-enhancers beyond gene regulation. RESULTS: In this study, through a comprehensive analysis of super-enhancers in 30 human cell/tissue types, we identified a new class of super-enhancers which are constitutively active across most cell/tissue types. These 'common' super-enhancers are associated with universally highly expressed genes in contrast to the canonical definition of super-enhancers that assert cell-type specific gene regulation. In addition, the genome sequence of these super-enhancers is highly conserved by evolution and among humans, advocating their universal function in genome regulation. Integrative analysis of 3D chromatin loops demonstrates that, in comparison to the cell-type specific super-enhancers, the cell-type common super-enhancers present a striking association with rapidly recovering loops. CONCLUSIONS: In this study, we propose that a new class of super-enhancers may play an important role in the early establishment of 3D chromatin structure.

3DIV: A 3D-genome Interaction Viewer and database.

Three-dimensional (3D) chromatin structure is an emerging paradigm for understanding gene regulation mechanisms. Hi-C (high-throughput chromatin conformation capture), a method to detect long-range chromatin interactions, allows extensive genome-wide investigation of 3D chromatin structure. However, broad application of Hi-C data have been hindered by the level of complexity in processing Hi-C data and the large size of raw sequencing data. In order to overcome these limitations, we constructed a database named 3DIV (a 3D-genome Interaction Viewer and database) that provides a list of long-range chromatin interaction partners for the queried locus with genomic and epigenomic annotations. 3DIV is the first of its kind to collect all publicly available human Hi-C data to provide 66 billion uniformly processed raw Hi-C read pairs obtained from 80 different human cell/tissue types. In contrast to other databases, 3DIV uniquely provides normalized chromatin interaction frequencies against genomic distance dependent background signals and a dynamic browsing visualization tool for the listed interactions, which could greatly advance the interpretation of chromatin interactions. '3DIV' is available at http://kobic.kr/3div.

[i] is Lighter and More Greenish Than [o]: Intrinsic Association Between Vowel Sounds and Colors.

It has recently been reported in the synesthesia literature that graphemes sharing the same phonetic feature tend to induce similar synesthetic colors. In the present study, we investigated whether phonetic properties are associated with colors in a specific manner among the general population, even when other visual and linguistic features of graphemes are removed. To test this hypothesis, we presented vowel sounds synthesized by systematically manipulating the position of the tongue body's center. Participants were asked to choose a color after hearing each sound. Results from the main experiment showed that lightness and chromaticity of matched colors exhibited systematic variations along the two axes of the position of the tongue body's center. Some non-random associations between vowel sounds and colors remained effective with pitch and intensity of the sounds equalized in the control experiment, which suggests that other acoustic factors such as inherent pitch of vowels cannot solely account for the current results. Taken together, these results imply that the association between phonetic features and colors is not random, and this synesthesia-like association is shared by people in the general population.

High-brightness laser imaging with tunable speckle reduction enabled by electroactive micro-optic diffusers.

High coherence of lasers is desirable in high-speed, high-resolution, and wide-field imaging. However, it also causes unavoidable background speckle noise thus degrades the image quality in traditional microscopy and more significantly in interferometric quantitative phase imaging (QPI). QPI utilizes optical interference for high-precision measurement of the optical properties where the speckle can severely distort the information. To overcome this, we demonstrated a light source system having a wide tunability in the spatial coherence over 43% by controlling the illumination angle, scatterer's size, and the rotational speed of an electroactive-polymer rotational micro-optic diffuser. Spatially random phase modulation was implemented for the lower speckle imaging with over a 50% speckle reduction without a significant degradation in the temporal coherence. Our coherence control technique will provide a unique solution for a low-speckle, full-field, and coherent imaging in optically scattering media in the fields of healthcare sciences, material sciences and high-precision engineering.

Nonlinear third harmonic generation at crystalline sapphires.

Third harmonic generation (THG) is a nonlinear optical phenomenon which can be applied in diverse research areas including interfacial studies, sub-wavelength light manipulation, and high sensitivity bio-molecular detection. Most precedent studies on THG have focused on dielectric and metallic materials, including silicon, gold, and germanium, due to their high nonlinear susceptibility. Sapphire, a widely-used optical substrate, has not been studied in depth for its third harmonic characteristics, despite its excellent optical transmission in the UV-visible range, high thermal conductance, and superior physical and chemical stability. In this research, we comprehensively studied THG at thin air-dielectric interfaces of sapphire wafers by controlling the wafer cutting planes, focusing depth, incidence angle, laser intensity, and input polarization of the input laser beam. These findings can lead to broader use of third harmonics for high-precision sapphire characterization, such as surface quality inspection, crystallinity determination, interfacial studies, delamination check, and real-time monitoring of crack propagation.