Deciphering the Impact of Defecation Frequency on Gut Microbiome Composition and Diversity.

This study explores the impact of defecation frequency on the gut microbiome structure by analyzing fecal samples from individuals categorized by defecation frequency: infrequent (1-3 times/week, n = 4), mid-frequent (4-6 times/week, n = 7), and frequent (daily, n = 9). Utilizing 16S rRNA gene-based sequencing and LC-MS/MS metabolome profiling, significant differences in microbial diversity and community structures among the groups were observed. The infrequent group showed higher microbial diversity, with community structures significantly varying with defecation frequency, a pattern consistent across all sampling time points. The Ruminococcus genus was predominant in the infrequent group, but decreased with more frequent defecation, while the Bacteroides genus was more common in the frequent group, decreasing as defecation frequency lessened. The infrequent group demonstrated enriched biosynthesis genes for aromatic amino acids and branched-chain amino acids (BCAAs), in contrast to the frequent group, which had a higher prevalence of genes for BCAA catabolism. Metabolome analysis revealed higher levels of metabolites derived from aromatic amino acids and BCAA metabolism in the infrequent group, and lower levels of BCAA-derived metabolites in the frequent group, consistent with their predicted metagenomic functions. These findings underscore the importance of considering stool consistency/frequency in understanding the factors influencing the gut microbiome.

Non-Invasive Alcohol Concentration Measurement Using a Spectroscopic Module: Outlook for the Development of a Drunk Driving Prevention System.

Alcohol acts as a central nervous system depressant and falls under the category of psychoactive drugs. It has the potential to impair vital bodily functions, including cognitive alertness, muscle coordination, and induce fatigue. Taking the wheel after consuming alcohol can lead to delayed responses in emergency situations and increases the likelihood of collisions with obstacles or suddenly appearing objects. Statistically, drivers under the influence of alcohol are seven times more likely to cause accidents compared to sober individuals. Various techniques and methods for alcohol measurement have been developed. The widely used breathalyzer, which requires direct contact with the mouth, raises concerns about hygiene. Methods like chromatography require skilled examiners, while semiconductor sensors exhibit instability in sensitivity over measurement time and has a short lifespan, posing structural challenges. Non-dispersive infrared analyzers face structural limitations, and in-vehicle air detection methods are susceptible to external influences, necessitating periodic calibration. Despite existing research and technologies, there remain several limitations, including sensitivity to external factors such as temperature, humidity, hygiene consideration, and the requirement for periodic calibration. Hence, there is a demand for a novel technology that can address these shortcomings. This study delved into the near-infrared wavelength range to investigate optimal wavelengths for non-invasively measuring blood alcohol concentration. Furthermore, we conducted an analysis of the optical characteristics of biological substances, integrated these data into a mathematical model, and demonstrated that alcohol concentration can be accurately sensed using the first-order modeling equation at the optimal wavelength. The goal is to minimize user infection and hygiene issues through a non-destructive and non-invasive method, while applying a compact spectrometer sensor suitable for button-type ignition devices in vehicles. Anticipated applications of this study encompass diverse industrial sectors, including the development of non-invasive ignition button-based alcohol prevention systems, surgeon's alcohol consumption status in the operating room, screening heavy equipment operators for alcohol use, and detecting alcohol use in close proximity to hazardous machinery within factories.

Ultra-Thin GaAs Single-Junction Solar Cells for Self-Powered Skin-Compatible Electrocardiogram Sensors.

GaAs thin-film solar cells have high efficiency, reliability, and operational stability, making them a promising solution for self-powered skin-conformal biosensors. However, inherent device thickness limits suitability for such applications, making them uncomfortable and unreliable in flexural environments. Therefore, reducing the flexural rigidity becomes crucial for integration with skin-compatible electronic devices. Herein, this study demonstrated a novel one-step surface modification bonding methodology, allowing a streamlined transfer process of ultra-thin (2.3 µm thick) GaAs solar cells on flexible polymer substrates. This reproducible technique enables strong bonding between dissimilar materials (GaAs-polydimethylsiloxane, PDMS) without high external pressures and temperatures. The fabricated solar cell showed exceptional performance with an open-circuit voltage of 1.018 V, short-circuit current density of 20.641 mA cm-2, fill factor of 79.83%, and power conversion efficiency of 16.77%. To prove the concept, the solar cell is integrated with a skin-compatible organic electrochemical transistor (OECT). Competitive electrical outputs of GaAs solar cells enabled high current levels of OECT under subtle light intensities lower than 50 mW cm-2, which demonstrates a self-powered electrocardiogram sensor with low noise (signal-to-noise ratio of 32.68 dB). Overall, this study presents a promising solution for the development of free-form and comfortable device structures that can continuously power wearable devices and biosensors.

Wide-range and selective detection of SARS-CoV-2 DNA via surface modification of electrolyte-gated IGZO thin-film transistors.

The 2019 coronavirus pandemic resulted in a massive global healthcare crisis, highlighting the necessity to develop effective and reproducible platforms capable of rapidly and accurately detecting SARS-CoV-2. In this study, we developed an electrolyte-gated indium-gallium-zinc-oxide (IGZO) thin-film transistor with sequential surface modification to realize the low limit of detection (LoD <50 fM) and a wide detection range from 50 fM to 5 µM with good linearity (R2 = 0.9965), and recyclability. The surface chemical modification was achieved to anchor the single strand of SARS-CoV-2 DNA via selective hybridization. Moreover, the minute electrical signal change following the chemical modification was investigated by in-depth physicochemical analytical techniques. Finally, we demonstrate fully recyclable biosensors based on oxygen plasma treatment. Owing to its cost-effective fabrication, rapid detection at the single-molecule level, and low detection limit, the proposed biosensor can be used as a point-of-care platform to perform timely and effective SARS-CoV-2 detection.

Synthesis of Superabsorbent Hydrogels with Predefined Geometries and Controlled Swelling Properties for Versatile 3D Cell Culture Scaffolds.

This research presents a simple but general method to prepare water-soluble-polymer-based superabsorbent hydrogels with predefined microscale geometries and controlled swelling properties. Unlike conventional hydrogel preparation methods based on bulk solution-phase cross-linking, poly(vinyl alcohol) is homogeneously mixed with polymer-based cross-linkers in the solution phase and thermally cross-linked in the solid phase after drying; the degree of cross-linking is modulated by controlling the cross-linker concentration, pH, and/or thermal annealing conditions. After the shape definition process, cross-linked films or electrospun nanofibers are treated with sulfuric acid to weaken hydrogen bonds and introduce sulfate functionality in polymer crystallites. The resultant superabsorbent hydrogels exhibit an isotropic expansion of the predefined geometry and tunable swelling properties. Particularly, hydrogel microfibers exhibit excellent optical transparency, good biocompatibility, large porosity, and controlled cell adhesion, leading to versatile 3D cell culture scaffolds that not only support immortalized cell lines and primary neurons but also enable stiffness-modulated cell adhesion studies.

Chiroptical Switching of Electrochromic Polymer Thin Films.

The interaction between light and chiroptical polymers plays a crucial role in chiroptics, spintronics, and chiral-spin selectivity. Despite considerable successes in creating dissymmetric polymer films, the elucidation of chiroptical activities under electrochemical switching remains unexplored. Here homogeneous chiral electrochromics is reported using chiral assembly of conjugated polymers through a transient solidification process with molecular chiral templates. In their neutral state, the chiral electrochromic polymers directly produce a remarkably dissymmetric polarization-dependent transmittance. The circular dichroism (CD) and dissymmetric transmission can be tuned by adjusting the doping level of the electrochemically active polymer films. Under high levels of oxidation, the chiroptical activities are reversed with strong bleaching in the visible, leading to formation of monosignate CD spectra over the infrared region. The matching between circular polarization handedness and chirality of chiroptical polymers makes a distinct impact on optical contrast and color switching dynamics due to the flipped chiroptical activities through polymer redox reactions. The differential circularly polarized transmission in the chiral see-through display can make a well-resolved color change in human eyes, demonstrating proof-of-concept devices for 3D imaging and information encryption. This work serves as a foundation to develop advanced on-chip fabrication of circular polarization-multiplexed display in flexible and highly integrated platforms.

Structural Engineering Three-Dimensional Nano-Heterojunction Networks for High-Performance Photochemical Sensing.

Nanoscale heterojunction networks are increasingly regarded as promising functional materials for a variety of optoelectronic and photocatalytic devices. Despite their superior charge-carrier separation efficiency, a major challenge remains in the optimization of their surface properties, with surface defects playing a major role in charge trapping and recombination. Here, we report the effective engineering of the photocatalytic properties of nanoscale heterojunction networks via deep ultraviolet photoactivation throughout their cross-section. For the first time, in-depth XPS analysis of very thick (∼10 µm) NixOy-ZnO films reveals localized p-n nanoheterojunctions with tunable oxygen vacancies (Vo) originating from both NixOy and ZnO nanocrystals. Optimizing the amount of oxygen vacancies leads to a 30-fold increase in the photochemoresistive response of these networks, enabling the detection of representative analyte concentrations down to 2 and 20 ppb at an optimal temperature of 150 °C and room temperature, respectively. Density functional theory calculations reveal that this performance enhancement is presumably due to an 80% increase in the analyte adsorption energy. This flexible nanofabrication approach in conjunction with straightforward vacancy control via photoactivation provides an effective strategy for engineering the photocatalytic activity of porous metal oxide semiconductor networks with applications in chemical sensors, photodetectors, and photoelectrochemical cells.

Aqueous electrolyte-gated solution-processed metal oxide transistors for direct cellular interfaces.

Biocompatible field-effect-transistor-based biosensors have drawn attention for the development of next-generation human-friendly electronics. High-performance electronic devices must achieve low-voltage operation, long-term operational stability, and biocompatibility. Herein, we propose an electrolyte-gated thin-film transistor made of large-area solution-processed indium-gallium-zinc oxide (IGZO) semiconductors capable of directly interacting with live cells at physiological conditions. The fabricated transistors exhibit good electrical performance operating under sub-0.5 V conditions with high on-/off-current ratios (>107) and transconductance (>1.0 mS) over an extended operational lifetime. Furthermore, we verified the biocompatibility of the IGZO surface to various types of mammalian cells in terms of cell viability, proliferation, morphology, and drug responsiveness. Finally, the prolonged stable operation of electrolyte-gated transistor devices directly integrated with live cells provides the proof-of-concept for solution-processed metal oxide material-based direct cellular interfaces.

Instant formation of horizontally ordered nanofibrous hydrogel films and direct investigation of peculiar neuronal cell behaviors atop.

BACKGROUND: Hydrogels have been widely used in many research fields owing to optical transparency, good biocompatibility, tunable mechanical properties, etc. Unlike typical hydrogels in the form of an unstructured bulk material, we developed aqueous dispersions of fiber-shaped hydrogel structures with high stability under ambient conditions and their application to various types of transparent soft cell culture interfaces with anisotropic nanoscale topography. METHOD: Nanofibers based on the polyvinyl alcohol and polyacrylic acid mixture were prepared by electrospinning and hydrogelified to nano-fibrous hydrogels (nFHs) after thermal crosslinking and sulfuric acid treatment. By modifying various material surfaces with positively-charged polymers, negatively-charged superabsorbent nFHs could be selectively patterned by employing micro-contact printing or horizontally aligned by applying shear force with a wired bar coater. RESULTS: The angular distribution of bar-coated nFHs was dramatically reduced to ± 20° along the applied shear direction unlike the drop-coated nFHs which exhibit random orientations. Next, various types of cells were cultured on top of transparent soft nFHs which showed good viability and attachment while their behaviors could be easily monitored by both upright and inverted optical microscopy. Particularly, neuronal lineage cells such as PC 12 cells and embryonic hippocampal neurons showed highly stretched morphology along the overall fiber orientation with aspect ratios ranging from 1 to 14. Furthermore, the resultant neurite outgrowth and migration behaviors could be effectively controlled by the horizontal orientation and the three-dimensional arrangement of underlying nFHs, respectively. CONCLUSION: We expect that surface modifications with transparent soft nFHs will be beneficial for various biological/biomedical studies such as fundamental cellular studies, neuronal/stem cell and/or organoid cultures, implantable probe/device coatings, etc.

Recent Advances in Biosensor Technologies for Point-of-Care Urinalysis.

Human urine samples are non-invasive, readily available, and contain several components that can provide useful indicators of the health status of patients. Hence, urine is a desirable and important template to aid in the diagnosis of common clinical conditions. Conventional methods such as dipstick tests, urine culture, and urine microscopy are commonly used for urinalysis. Among them, the dipstick test is undoubtedly the most popular owing to its ease of use, low cost, and quick response. Despite these advantages, the dipstick test has limitations in terms of sensitivity, selectivity, reusability, and quantitative evaluation of diseases. Various biosensor technologies give it the potential for being developed into point-of-care (POC) applications by overcoming these limitations of the dipstick test. Here, we present a review of the biosensor technologies available to identify urine-based biomarkers that are typically detected by the dipstick test and discuss the present limitations and challenges that future development for their translation into POC applications for urinalysis.

Automated Real-Time Evaluation of Condylar Movement in Relation to Three-Dimensional Craniofacial and Temporomandibular Morphometry in Patients with Facial Asymmetry.

The aim of this study was to investigate the correlation between craniofacial morphology, temporomandibular joint (TMJ) characteristics, and condylar functional movement in patients with facial asymmetry using an up-to-date automated real-time jaw-tracking system. A total of 30 patients with mandibular asymmetry and prognathism were included. Three-dimensional (3D) craniofacial and TMJ morphometric variables were analyzed in images captured using cone-beam computed tomography. Three-dimensional condylar movements were recorded during the opening, protrusion, and laterotrusion of the jaw and divided into those for deviated and non-deviated sides. Overall functional and morphometric variables were compared between the sides by a paired t-test. Pearson's correlation analysis and factor analysis were also performed. As a result, significant differences were found between the sides in morphometric and functional variables. The condylar path length was significantly longer and steeper on the deviated side during protrusion and lateral excursion. TMJ morphometric asymmetry, more so than the craniofacial morphologic asymmetry, seemed to be reflected in the functional asymmetry, representing different correlations between the sides, as supported by factor analysis. This study provides evidence explaining why the asymmetric condylar path remained unchanged even after orthognathic surgery for the correction of craniofacial asymmetry.

Rapid and Reliable Formation of Highly Densified Bilayer Oxide Dielectrics on Silicon Substrates via DUV Photoactivation for Low-Voltage Solution-Processed Oxide Thin-Film Transistors.

In this research, we report the rapid and reliable formation of high-performance nanoscale bilayer oxide dielectrics on silicon substrates via low-temperature deep ultraviolet (DUV) photoactivation. The optical analysis of sol-gel aluminum oxide films prepared at various concentrations reveals the processable film thickness with DUV photoactivation and its possible generalization to the formation of various metal oxide films on silicon substrates. The physicochemical and electrical characterizations confirm that DUV photoactivation accelerates the efficient formation of a highly dense aluminum oxide and aluminum silicate bilayer (17 nm) on heavily doped silicon at 150 °C within 5 min owing to the efficient thermal conduction on silicon, resulting in excellent dielectric properties in terms of low leakage current (∼10-8 A/cm2 at 1.0 MV/cm) and high areal capacitance (∼0.4 µF/cm2 at 100 kHz) with narrow statistical distributions. Additionally, the sol-gel bilayer oxide dielectrics are successfully combined with a sol-gel indium-gallium-zinc oxide semiconductor via two successive DUV photoactivation cycles, leading to the efficient fabrication of solution-processed oxide thin-film transistors on silicon substrates with an operational voltage below 0.5 V. We expect that in combination with large-area printing, the bilayer oxide dielectrics are beneficial for large-area solution-based oxide electronics on silicon substrates, while DUV photoactivation can be applied to various types of solution-processed functional metal oxides such as phase-transition memories, ferroelectrics, photocatalysts, charge-transporting interlayers and passivation layers, etc. on silicon substrates.

Preparation and Characterization of Bimetallic Fe-Ni Oxide Nanoparticles Using Liquid Phase Plasma Process.

The Fe-Ni oxide bimetallic nanoparticles (FNOBNPs) were synthesized in the liquid phase plasma (LPP) method employed an iron chloride and nickel chloride as metal precursors. The sphericalshaped FNOBNPs were synthesized by the LPP process and, the size of particles was growing along with the progression of LPP reaction. The synthesized FNOBNPs were comprised of Fe3O4 and NiO. Iron had a higher reduction potential than nickel and resulted in higher iron composition in the synthesized FNOBNPs. The control of molar ratio of metal precursors in initial reactant solution was found that it could be employed as a means to control the composition of the elements in FNOBNP.

Facile Synthesis of Chromium Oxide on Activated Carbon Electrodes for Electrochemical Capacitor Application.

Chromium oxide/carbon nanocomposites (COCNC) were synthesized by using a liquid phase plasma process, and the electrical properties of the supercapacitor electrode were investigated. Spherical chromium oxide (Cr2O3) nanoparticles with the size of 100-150 nm were dispersed uniformly on activated carbon powder surface. The quantity of chromium oxide nanoparticle precipitate increased with increasing LPP reaction time and the specific capacitance of COCNC increased with increasing LPP reaction time.

Influence of PEDOT:PSS crystallinity and composition on electrochemical transistor performance and long-term stability.

Owing to the mixed electron/hole and ion transport in the aqueous environment, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based organic electrochemical transistor has been regarded as one of the most promising device platforms for bioelectronics. Nonetheless, there exist very few in-depth studies on how intrinsic channel material properties affect their performance and long-term stability in aqueous environments. Herein, we investigated the correlation among film microstructural crystallinity/composition, device performance, and aqueous stability in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) films. The highly organized anisotropic ordering in crystallized conducting polymer films led to remarkable device characteristics such as large transconductance (∼20 mS), extraordinary volumetric capacitance (113 F·cm-3), and unprecedentedly high [µC*] value (∼490 F·cm-1V-1s-1). Simultaneously, minimized poly(styrenesulfonate) residues in the crystallized film substantially afforded marginal film swelling and robust operational stability even after >20-day water immersion, >2000-time repeated on-off switching, or high-temperature/pressure sterilization. We expect that the present study will contribute to the development of long-term stable implantable bioelectronics for neural recording/stimulation.

Liquid Phase Plasma Synthesis of Iron Oxide Nanoparticles on Nitrogen-Doped Activated Carbon Resulting in Nanocomposite for Supercapacitor Applications.

Iron oxide nanoparticles supported on nitrogen-doped activated carbon powder were synthesized using an innovative plasma-in-liquid method, called the liquid phase plasma (LPP) method. Nitrogen-doped carbon (NC) was prepared by a primary LPP reaction using an ammonium chloride reactant solution, and an iron oxide/NC composite (IONCC) was prepared by a secondary LPP reaction using an iron chloride reactant solution. The nitrogen component at 3.77 at. % formed uniformly over the activated carbon (AC) surface after a 1 h LPP reaction. Iron oxide nanoparticles, 40~100 nm in size, were impregnated homogeneously over the NC surface after the LPP reaction, and were identified as Fe3O4 by X-ray photoelectron spectroscopy and X-ray diffraction. NC and IONCCs exhibited pseudo-capacitive characteristics, and their specific capacitance and cycling stability were superior to those of bare AC. The nitrogen content on the NC surface increased the compatibility and charge transfer rate, and the composites containing iron oxide exhibited a lower equivalent series resistance.

Ultralow-Temperature Solution-Processed Aluminum Oxide Dielectrics via Local Structure Control of Nanoclusters.

Oxide dielectric materials play a key role in a wide range of high-performance solid-state electronics from semiconductor devices to emerging wearable and soft bioelectronic devices. Although several previous advances are noteworthy, their typical processing temperature still far exceeds the thermal limitations of soft materials, impeding their wide utilization in these emerging fields. Here, we report an innovative route to form highly reliable aluminum oxide dielectric films using an ultralow-temperature (<60 °C) solution process with a class of oxide nanocluster precursors. The extremely low-temperature synthesis of oxide dielectric films was achieved by using low-impurity, bulky metal-oxo-hydroxy nanoclusters combined with a spatially controllable and highly energetic light activation process. It was noteworthy that the room-temperature light activation process was highly effective in dissociating the metal-oxo-hydroxy clusters, enabling the formation of a dense atomic network at low temperature. The ultralow-temperature solution-processed oxide dielectrics demonstrated high breakdown field (>6 MV cm-1), low leakage (∼1 × 10-8 A cm-2 at 2 MV cm-1), and excellent electrical stability comparable to those of vacuum-deposited and high-temperature-processed dielectric films. For potential applications of the oxide dielectrics, transparent metal oxides and carbon nanotube active devices as well as integrated circuits were implemented directly on both ultrathin polymeric and highly stretchable substrates.

Three-dimensional alteration of constricted alveolar ridge affected by root thrusting with and without open-flap decortication.

OBJECTIVE: To investigate the morphometric and histological alterations of the constricted alveolar ridge when affected by root thrusting with and without open-flap decortication. MATERIALS AND METHODS: Eight beagles were divided into three groups: C, control without root thrusting; R, root thrusting only; RD, root thrusting with alveolar decortication. The ridge constriction model was prepared in 16 mandibular quadrants after extraction of the third premolars. Reciprocal root thrusting of the second and fourth premolars was performed toward the constricted ridge for 10 weeks, having a moment of 900 g-mm. Open-flap decortication was conducted on the constricted bone surface in group RD. Micro-CT-based histomorphometric analysis and trichrome-staining-based tissue fractional analysis were performed to evaluate morphometric and microstructural changes on the ridge. RESULTS: Group R revealed a higher percentage of bone volume (P < .001), lower bone mineral density (P < .01), and higher trabecular number (P < .001) than did group C, which was supported by a higher bone fraction woven to lamellar bone (P < .05) resulting from histologic fractional analysis. However, group RD showed no significant difference from group C. CONCLUSIONS: Root thrusting toward the constricted ridge induced hypertrophic bone modeling with a high trabecular fraction on the ridge. However, combined open-flap decortication with root thrusting did not improve the volume or quality of the constricted ridge.

Subtypes of Maxillomandibular Advancement Surgery for Patients With Obstructive Sleep Apnea.

Maxillomandibular advancement (MMA) surgery, which is the most effective treatment modality for patients with moderate-to-severe obstructive sleep apnea with apparent skeletal discrepancies, has been modified in conjunction with segmental osteotomies, counterclockwise rotation of maxillomandibular complex, and other adjunctive procedures. However, any single type of MMA could not treat or cure all the patients with obstructive sleep apnea showing different dentofacial and pharyngeal patterns. We aimed to suggest critical decision factors for the selective application of MMA subtypes, categorized as straight MMA with genioplasty, rotational MMA, segmental MMA, and segmental-rotational MMA, in the surgical treatment objective process: anteroposterior position of maxilla, upper lip projection, overjet, lower incisor inclination as sagittal factors, and upper incisor exposure and occlusal plane angle as vertical factors. This case series deserves a clinical basis on the way of case-by-case application of the optimal MMA subtype based on the successful treatment outcomes with short-term stability.

Sub-0.5 V Highly Stable Aqueous Salt Gated Metal Oxide Electronics.

Recently, growing interest in implantable bionics and biochemical sensors spurred the research for developing non-conventional electronics with excellent device characteristics at low operation voltages and prolonged device stability under physiological conditions. Herein, we report high-performance aqueous electrolyte-gated thin-film transistors using a sol-gel amorphous metal oxide semiconductor and aqueous electrolyte dielectrics based on small ionic salts. The proper selection of channel material (i.e., indium-gallium-zinc-oxide) and precautious passivation of non-channel areas enabled the development of simple but highly stable metal oxide transistors manifested by low operation voltages within 0.5 V, high transconductance of ~1.0 mS, large current on-off ratios over 10(7), and fast inverter responses up to several hundred hertz without device degradation even in physiologically-relevant ionic solutions. In conjunction with excellent transistor characteristics, investigation of the electrochemical nature of the metal oxide-electrolyte interface may contribute to the development of a viable bio-electronic platform directly interfacing with biological entities in vivo.