Flexible Dry Electrode Based on a Wrinkled Surface That Uses Carbon Nanotube/Polymer Composites for Recording Electroencephalograms.

Electroencephalography (EEG) captures minute electrical signals emanating from the brain. These signals are vulnerable to interference from external noise and dynamic artifacts; hence, accurately recording such signals is challenging. Although dry electrodes are convenient, their signals are of limited quality; consequently, wet electrodes are predominantly used in EEG. Therefore, developing dry electrodes for accurately and stably recording EEG signals is crucial. In this study, we developed flexible dry electrodes using polydimethylsiloxane (PDMS)/carbon-nanotube (CNT) composites with isotropically wrinkled surfaces that effectively combine the advantages of wet and dry electrodes. Adjusting the PDMS crosslinker ratio led to good adhesion, resulting in a highly adhesive CNT/PDMS composite with a low Young's modulus that exhibited excellent electrical and mechanical properties owing to its ability to conformally contact skin. The isotropically wrinkled surface also effectively controls dynamic artifacts during EEG signal detection and ensures accurate signal analysis. The results of this study demonstrate that dry electrodes based on flexible CNT/PDMS composites and corrugated structures can outperform wet electrodes. The introduction of such electrodes is expected to enable the accurate analysis and monitoring of EEG signals in various scenarios, including clinical trials.

Therapeutic Potential of 4-Hexylresorcinol in Preserving Testicular Function in Streptozotocin-Induced Diabetic Rats.

It is known that many diabetic patients experience testicular atrophy. This study sought to investigate the effect of 4-hexylresorcinol (4HR) on testicular function in rats with streptozotocin (STZ)-induced diabetes, focusing on testicular weight, sperm motility, histological alterations, and serum testosterone levels to understand the efficacy of 4HR on testes. Our findings reveal that 4HR treatment significantly improves testicular health in diabetic rats. Notably, the STZ group exhibited a testicular weight of 1.22 ± 0.48 g, whereas the STZ/4HR group showed a significantly enhanced weight of 1.91 ± 0.26 g (p < 0.001), aligning closely with the control group's weight of 1.99 ± 0.17 g and the 4HR group's weight of 2.05 ± 0.24 g, indicating no significant difference between control and 4HR groups (p > 0.05). Furthermore, the STZ/4HR group demonstrated significantly improved sperm motility compared to the STZ group, with apoptotic indicators notably reduced in the STZ/4HR group relative to the STZ group (p < 0.05). These results underscore the therapeutic potential of 4HR for maintaining testicular function under diabetic conditions.

Workout with a Smartwatch: A Cross-Sectional Study of the Effects of Smartwatch Attributes on Flow Experience and Exercise Intentions Depending on Exercise Involvement.

Smartwatches are emerging as effective tools to promote exercise and physical activities in the healthcare industry. However, little is known about how smartwatch attributes facilitate exercise and for whom such attributes are more effective for exercise. Accordingly, the purpose of this study was to explore the structural relationship between smartwatch attributes, flow experience, and continued exercise intentions and to examine the moderating role of exercise involvement in the structural relationship. For this, a total of 600 participants were recruited via a professional survey firm in South Korea based on a multi-stage random sampling method and used for data analyses, including confirmatory factor analysis (CFA), structural equation modeling (SEM), and multi-group SEM. All survey items were adopted from the existing literature on healthcare, flow experience, and wearable device technologies. The results revealed that smartwatch attributes, including interactivity (γ = 0.234, p < 0.001/γ = 0.235, p < 0.001), autonomy (γ = 0.225, p < 0.001/γ = 0.172, p < 0.001), wearability (γ = 0.104, p < 0.05/γ = 0.106, p < 0.05), convenience (γ = 0.209, p < 0.001/γ = 0.214, p < 0.001), and experiential novelty (γ = 0.221, p < 0.001/γ = 0.281, p < 0.001) enhanced flow experience (absorption/enjoyment) during exercise. Furthermore, flow experience (absorption/enjoyment) was found to positively influence exercise intention (ß = 0.511, p < 0.001/ß = 0.239, p < 0.001). Lastly, exercise involvement was found to modulate the structural relationships among smartwatch attributes, flow experience, and exercise intention (∆χ2 = 23.231, ∆df = 12, p < 0.05). By investigating these dynamics, this study contributes to shared knowledge not only in the healthcare literature but also in the wearable-technology literature. The results of the current study also provide useful guidelines for practitioners in the wearable-device and healthcare industries to develop optimal features of smartwatches for exercise and physical activities.

The optimal scaffold for silk sericin-based bone graft: collagen versus gelatin.

BACKGROUND: Silk sericin is an active ingredient in bone grafts. However, the optimal scaffold for silk sericin has yet to be identified. METHOD: A critical-sized bone defect model in rat calvaria was used to evaluate bone regeneration. Silk sericin from Yeonnokjam, Bombyx mori, was incorporated into gelatin (group G, n = 6) and collagen (group C, n = 6). Bone regeneration was evaluated using micro-computed tomography (mCT) and histology. RESULTS: Group C showed a larger bone volume than group G in the mCT analysis (P = 0.001). Histological analysis showed a larger area of bony defects in group G than in group C. The bone regeneration area in group C was significantly larger than that in group G (P = 0.003). CONCLUSION: Compared with gelatin, collagen shows better bone regeneration in silk sericin-based bone grafts.

Comparative Study of Carbon Nanotube Composites as Capacitive and Piezoresistive Pressure Sensors under Varying Conditions.

Conducting polymer composites consisting of carbon nanotubes (CNTs) as a conductive filler and polydimethylsiloxane (PDMS) as a polymer matrix were fabricated to investigate their capacitive and piezoresistive effects as pressure sensors. The pressure-sensing behavior and mechanism of the composites were compared in terms of basic configuration with a parallel plate structure. Various sensing experiments, such as sensitivity, repeatability, hysteresis, and temperature dependence according to the working principle, were conducted with varying filler contents. The hysteresis and repeatability of the pressure-sensing properties were investigated using cyclic tensile tests. In addition, a temperature test was performed at selected temperatures to monitor the change in the resistance/capacitance.

MicroRNA-18a regulates the metastatic properties of oral squamous cell carcinoma cells via HIF-1α expression.

BACKGROUND: Rapid metastasis of oral squamous cell carcinoma (OSCC) is associated with a poor prognosis and a high mortality rate. However, the molecular mechanisms underlying OSCC metastasis have not been fully elucidated. Although deregulated expression of microRNA (miRNA) has a crucial role in malignant cancer progression, the biological function of miRNA in OSCC progression remains unclear. This study aimed to investigate the function of miRNA-18a in OSCC metastatic regulation via hypoxia-inducible factor 1α (HIF-1α). METHODS: miRNA-18a-5p (miRNA-18a) expressions in patients with OSCC (n = 39) and in OSCC cell lines (e.g., YD-10B and HSC-2 cells) were analyzed using quantitative real-time polymerase chain reaction. HIF-1α protein expressions in OSCC cells treated with miRNA-18a mimics or combined with cobalt chloride were analyzed using western blotting. The miRNA-18a expression-dependent proliferation and invasion abilities of OSCC cells were analyzed using MTT assay, EdU assay, and a Transwell® insert system. RESULTS: miRNA-18a expression was significantly lower in OSCC tissue than in the adjacent normal tissue. In OSCC cell lines, HIF-1α expression was significantly decreased by miRNA-18a mimic treatment. Furthermore, the migration and invasion abilities of OSCC cells were significantly decreased by miRNA-18a mimics and significantly increased by the overexpression of HIF-1α under hypoxic conditions relative to those abilities in cells treated only with miRNA-18a mimics. CONCLUSIONS: miRNA-18a negatively affects HIF-1α expression and inhibits the metastasis of OSCC, thereby suggesting its potential as a therapeutic target for antimetastatic strategies in OSCC.

PUFTAP-IoT: PUF-Based Three-Factor Authentication Protocol in IoT Environment Focused on Sensing Devices.

In IoT-based environments, smart services can be provided to users under various environments, such as smart homes, smart factories, smart cities, smart transportation, and healthcare, by utilizing sensing devices. Nevertheless, a series of security problems may arise because of the nature of the wireless channel in the Wireless Sensor Network (WSN) for utilizing IoT services. Authentication and key agreements are essential elements for providing secure services in WSNs. Accordingly, two-factor and three-factor-based authentication protocol research is being actively conducted. However, IoT service users can be vulnerable to ID/password pair guessing attacks by setting easy-to-remember identities and passwords. In addition, sensors and sensing devices deployed in IoT environments are vulnerable to capture attacks. To address this issue, in this paper, we analyze the protocols of Chunka et al., Amintoosi et al., and Hajian et al. and describe their security vulnerabilities. Moreover, this paper introduces PUF and honey list techniques with three-factor authentication to design protocols resistant to ID/password pair guessing, brute-force, and capture attacks. Accordingly, we introduce PUFTAP-IoT, which can provide secure services in the IoT environment. To prove the security of PUFTAP-IoT, we perform formal analyses through Burrows Abadi Needham (BAN) logic, Real-Or-Random (ROR) model, and scyther simulation tools. In addition, we demonstrate the efficiency of the protocol compared with other authentication protocols in terms of security, computational cost, and communication cost, showing that it can provide secure services in IoT environments.

Evaluation of postoperative changes in condylar positions after orthognathic surgery using balanced orthognathic surgery system.

BACKGROUND: Many studies on maintaining the condyle in a normal or anatomical position during orthognathic surgery have been conducted to stabilize surgical outcomes and prevent iatrogenic temporomandibular joint complications. The aim of this study is to evaluate the changes in condylar positions after orthognathic surgery using virtual surgical planning via the balanced orthognathic surgery (BOS) system. METHODS: Postoperative changes in condylar position were retrospectively evaluated in 22 condyles of 11 patients with skeletal class III malocclusion who underwent orthognathic surgery using virtual surgical planning via the BOS system. The center point coordinates of the condylar head before and after orthognathic surgery were analyzed using voxel-based registration. RESULTS: Changes in the condylar position mainly occurred downward in the y-axis (-1.09 ± 0.62 mm) (P < 0.05). The change in the x-axis (0.02 ± 0.68 mm) and z-axis (0.01 ± 0.48 mm) showed no significant difference between before and after orthognathic surgery. CONCLUSION: These results indicate that the changes in the condylar positions after orthognathic surgery using virtual surgical planning via the BOS system mainly occurred downward in the y-axis, with slight changes in the x- and z-axes. The change in the condylar position after orthognathic surgery using the BOS system is clinically acceptable.

4-Hexylresorcinol Treatment before Degumming Increases the ß-Sheet Structure of Silk Sericin and BMP-2 Expression in RAW264.7 Cells.

Silk sericin is a degumming product used by the silk industry. The degumming process can affect the protein structure and molecular weight of silk sericin. The present study examined how pretreatment with 4-hexylresorcinol (4HR) affects the biomedical properties of silk sericin. Before the degumming process, silkworm cocoons were treated with 4HR solution. The protein structure of the final degumming product was evaluated by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy. Untreated silk sericin (S) and silk sericin pretreated with 4HR (S+4HR) were added to RAW264.7 cells, and the expression of BMP-2 was determined. The bone-regenerating capacity of S+4HR was evaluated using the critical-sized rat calvarial defect model. Compared with S, S+4HR showed an increase in ß-sheet structures. Administration of S+4HR to RAW264.7 cells increased expression of BMP-2, mainly via the TLR-mediated signaling pathway. Bone volume, as measured by micro-computerized tomography, was significantly greater in the S+4HR group than in the S, gelatin alone, and unfilled control groups (p < 0.05 each). Expression of BMP-2 and runx2 in tissue specimens was significantly higher following treatment with S+4HR than with S (p < 0.05). Taken together, these findings show that 4HR pretreatment before the degumming process increased the ß-sheet structure of silk sericin, as well as inducing BMP-2 expression and bone regeneration ability.

Silk sericin application increases bone morphogenic protein-2/4 expression via a toll-like receptor-mediated pathway.

Bone morphogenic protein-2/4 (BMP-2/4) is an osteoinductive protein that accelerates osteogenesis when administered to bony defects. Sericin is produced by silkworms, and has a biological activity that differs depending on the degumming method used. Our results indicated that the high molecular weight fraction of silk sericin (MW > 30 kDa) obtained via sonication had a more abundant ß-sheet structure than the low molecular weight fraction. Administration of the ß-sheet structure silk sericin increased BMP-2/4 expression in a dose-dependent manner in RAW264.7 cells and human monocytes. This sericin increased the expression levels of toll-like receptor (TLR)-2, TLR-3, and TLR-4 in RAW264.7 cells. Application of a TLR-2 antibody or TLR pathway blocker decreased BMP-2/4 expression following sericin administration. In the animal model, the bone volume and BMP-2/4 expression were higher in rats treated with a sericin-incorporated gelatin sponge than in rats treated with a gelatin sponge alone or a sponge-incorporated with denatured sericin. In conclusion, sericin with a more abundant ß-sheet structure increased BMP-2/4 expression and bone formation better than sericin with a less abundant ß-sheet structure.

Effects of 4-Hexylresorcinol on Craniofacial Growth in Rats.

4-Hexylresorcinol (4HR) has been used as a food additive, however, it has been recently demonstrated as a Class I histone deacetylase inhibitor (HDACi). Unlike other HDACi, 4HR can be taken through foods. Unfortunately, some HDACi have an influence on craniofacial growth, therefore, the purpose of this study was to evaluate the effects of 4HR on craniofacial growth. Saos-2 cells (osteoblast-like cells) were used for the evaluation of HDACi and its associated activities after 4HR administration. For the evaluation of craniofacial growth, 12.8 mg/kg of 4HR was administered weekly to 4 week old rats (male: 10, female: 10) for 12 weeks. Ten rats were used for untreated control (males: 5, females: 5). Body weight was recorded every week. Serum and head samples were collected at 12 weeks after initial administration. Craniofacial growth was evaluated by micro-computerized tomography. Serum was used for ELISA (testosterone and estrogen) and immunoprecipitation high-performance liquid chromatography (IP-HPLC). The administration of 4HR (1-100 µM) showed significant HDACi activity (p < 0.05). Body weight was significantly different in male rats (p < 0.05), and mandibular size was significantly smaller in 4HR-treated male rats with reduced testosterone levels. However, the mandibular size was significantly higher in 4HR treated female rats with increased growth hormone levels. In conclusion, 4HR had HDACi activity in Saos-2 cells. The administration of 4HR on growing rats showed different responses in body weight and mandibular size between sexes.

A Secure and Lightweight Authentication Protocol for IoT-Based Smart Homes.

With the information and communication technologies (ICT) and Internet of Things (IoT) gradually advancing, smart homes have been able to provide home services to users. The user can enjoy a high level of comfort and improve his quality of life by using home services provided by smart devices. However, the smart home has security and privacy problems, since the user and smart devices communicate through an insecure channel. Therefore, a secure authentication protocol should be established between the user and smart devices. In 2020, Xiang and Zheng presented a situation-aware protocol for device authentication in smart grid-enabled smart home environments. However, we demonstrate that their protocol can suffer from stolen smart device, impersonation, and session key disclosure attacks and fails to provide secure mutual authentication. Therefore, we propose a secure and lightweight authentication protocol for IoT-based smart homes to resolve the security flaws of Xiang and Zheng's protocol. We proved the security of the proposed protocol by performing informal and formal security analyses, using the real or random (ROR) model, Burrows-Abadi-Needham (BAN) logic, and the Automated Validation of Internet Security Protocols and Applications (AVISPA) tool. Moreover, we provide a comparison of performance and security properties between the proposed protocol and related existing protocols. We demonstrate that the proposed protocol ensures better security and lower computational costs than related protocols, and is suitable for practical IoT-based smart home environments.

Natural Bone Healing In Compromised Sockets After Tooth Extraction: Digital Measurement Methods With Cone-Beam Computed Tomography.

This study aimed to evaluate bone regeneration within infected extraction sockets with bone defects using cone-beam computed tomography (CBCT) at a 1-year follow-up after implant placement in a prosthetically driven implant position. Forty-eight patients requiring premolar or molar tooth extraction due to bone defects caused by periodontal diseases were included. Vertical and horizontal bone volumes were assessed by overlapping the CBCT scan images with the full digital process. At 1-year post-extraction, a prosthetically-driven implant was planned using virtual implant planning software. At 1 year after extraction, CBCT revealed significant horizontal and vertical bone gains; an overall mean buccolingual bone width gain of 5.46 ± 2.87 mm, and an overall mean vertical bone gain of 0.27 ± 1.28 mm for the lingual bone plate level and 3.50 ± 1.81 mm for the buccal bone plate level were observed. Except for 4 (out of 48) sites, implants were virtually positioned in the center of the edentulous spaces. In summary, despite the dimensional changes after tooth extraction in compromised posterior sockets, there was sufficient bone for placing an implant using the prosthetically driven approach.

Increased Level of Vascular Endothelial Growth Factors by 4-hexylresorcinol is Mediated by Transforming Growth Factor-ß1 and Accelerates Capillary Regeneration in the Burns in Diabetic Animals.

4-Hexyl resorcinol (4HR) is an organic compound and has been used in skin care application. 4HR is an M2-type macrophage activator and elevates vascular endothelial growth factor (VEGF) expression via the hypoxia-inducible factor (HIF)-independent pathway. As endothelial cells are important in wound healing, the human umbilical vein endothelial cells (HUVECs) were treated with 4HR, and changes in VEGF-A, -C, and transforming growth factor-ß1 (TGF-ß1) expression were investigated. The administration of 4HR increased the expression level of VEGF-A, -C, and TGF-ß1. The application of TGF-ß1 protein also increased the expression level of VEGF-A and -C. Knockdown with small interfering RNA (siRNA) targeting to TGF-ß1 and the selective chemical inhibition (A83-01) to ALK5 confirmed the involvement of the TGF-ß signaling pathway in the 4-HR-mediated VEGFs expression. 4HR application in a burn model of diabetic rats demonstrated an increased level of angiogenic proteins with wound healing. Compared to sericin application, the 4HR application group showed more prominent capillary regeneration. Collectively, 4HR activated TGF-ß1/ALK5/VEGFs signaling in endothelial cells and induced vascular regeneration and remodeling for wound healing.

Stress Distribution on the Prosthetic Screws in the All-on-4 Concept: A Three-Dimensional Finite Element Analysis.

The all-on-4 concept, which is used to rehabilitate edentulous patients, can present with mechanical complications such as screw loosening and fracture. The purpose of this study was to evaluate the stress patterns induced in the prosthetic screws by the different prosthetic screw and abutment designs in the all-on-4 concept using finite element analysis. Von Mises stress values on 6 groups of each screw type, including short and narrow screw, short abutment; short and wide screw, short abutment; long and wide screw, short abutment; short and narrow screw, long abutment; short and wide screw, long abutment; and long and wide screw, long abutment, were compared under a cantilever loading of 200 N that was applied on the farther posterior to the position of the connection between the distal implant and the metal framework. Posterior prosthetic screws showed higher stress values than anterior prosthetic screws. The stress values in posterior prosthetic screws decreased as the length and diameter increased. In conclusion, the long and wide screw design offers advantages in stress distribution when compared with the short and narrow design.

Retrospective comparative clinical study for silk mat application into extraction socket.

BACKGROUND: Silk mats have been approved for clinical trials by the Korean Food and Drug Administration as membranes for guided tissue regeneration (GTR). In this study, silk mat application was compared to high-density polytetrafluoroethylene (dPTFE) membrane application or no membrane group. METHODS: To compare the silk mat group to the dPTFE group or the no membrane group, a retrospective sample collection was conducted. Bony defects were measured at the time of extraction (T0) and then at 3 months (T1) and 6 months after extraction (T2) on a digital panoramic view. Bone gain (BG) was calculated by subtracting from the bony defect at T0 to the bony defect at each follow-up. RESULTS: The BG at T2 was 2.44 ± 2.49 mm, 4.18 ± 1.80 mm, and 4.24 ± 2.05 mm in the no membrane group, silk mat group, and dPTFE group, respectively. Both membrane groups had significantly higher BG than BG in the no membrane group at T2 (P < 0.05). CONCLUSIONS: Both membrane groups showed higher BG than the no membrane group.

A digital technique for fabricating an interim implant-supported fixed prosthesis immediately after implant placement in patients with complete edentulism.

The conversion of a denture into an interim implant-supported, screw-retained restoration has become the standard method for immediate interim restoration in patients with complete edentulism. The most critical steps of the denture conversion process are the creation of appropriate denture access holes to prevent displacement of the denture by the interim cylinders and removal of the denture flanges to facilitate both good esthetics and accessibility for oral hygiene after the denture is connected to the interim cylinders. This article presents a digital technique for designing and fabricating an interim implant-supported, fixed prosthesis for edentulous patients. The interim prosthesis has cylinder access holes that are digitally prefabricated and a denture flange part that is designed to be easily sectioned. This technique facilitates more straightforward and efficient immediate restoration for edentulous patients after implant placement.

Anatomical repair of a bilateral Tessier No. 3 cleft by midfacial advancement.

BACKGROUND: Bilateral Tessier number 3 clefts are extremely rare, and their surgical treatments have not been well established. CASE PRESENTATION: The authors describe the case of a patient with a right Tessier number 3, 11 facial cleft with microphthalmia, a left Tessier number 3 facial cleft with anophthalmia, and cleft palate. We repaired simultaneously the bilateral soft tissue clefts by premaxillary repositioning, cleft lip repair, facial cleft repair by nasal lengthening, midfacial advancement, and an upper eyelid transposition flap with repositioning both the medial canthi. Postoperatively, the patient showed an esthetically acceptable face without unnatural scars. CONCLUSIONS: We achieved good results functionally and esthetically by midfacial advancement with facial muscle reposition instead of traditional interdigitating Z-plasties. The surgical modality of our anatomical repair and 3 months follow-up results are presented.

Recent advances in the reconstruction of cranio-maxillofacial defects using computer-aided design/computer-aided manufacturing.

With the development of computer-aided design/computer-aided manufacturing (CAD/CAM) technology, it has been possible to reconstruct the cranio-maxillofacial defect with more accurate preoperative planning, precise patient-specific implants (PSIs), and shorter operation times. The manufacturing processes include subtractive manufacturing and additive manufacturing and should be selected in consideration of the material type, available technology, post-processing, accuracy, lead time, properties, and surface quality. Materials such as titanium, polyethylene, polyetheretherketone (PEEK), hydroxyapatite (HA), poly-DL-lactic acid (PDLLA), polylactide-co-glycolide acid (PLGA), and calcium phosphate are used. Design methods for the reconstruction of cranio-maxillofacial defects include the use of a pre-operative model printed with pre-operative data, printing a cutting guide or template after virtual surgery, a model after virtual surgery printed with reconstructed data using a mirror image, and manufacturing PSIs by directly obtaining PSI data after reconstruction using a mirror image. By selecting the appropriate design method, manufacturing process, and implant material according to the case, it is possible to obtain a more accurate surgical procedure, reduced operation time, the prevention of various complications that can occur using the traditional method, and predictive results compared to the traditional method.

Recent advances in dental implants.

Dental implants are a common treatment for the loss of teeth. This paper summarizes current knowledge on implant surfaces, immediate loading versus conventional loading, short implants, sinus lifting, and custom implants using three-dimensional printing. Most of the implant surface modifications showed good osseointegration results. Regarding biomolecular coatings, which have been recently developed and studied, good results were observed in animal experiments. Immediate loading had similar clinical outcomes compared to conventional loading and can be used as a successful treatment because it has the advantage of reducing treatment times and providing early function and aesthetics. Short implants showed similar clinical outcomes compared to standard implants. A variety of sinus augmentation techniques, grafting materials, and alternative techniques, such as tilted implants, zygomatic implants, and short implants, can be used. With the development of new technologies in three-dimension and computer-aided design/computer-aided manufacturing (CAD/CAM) customized implants can be used as an alternative to conventional implant designs. However, there are limitations due to the lack of long-term studies or clinical studies. A long-term clinical trial and a more predictive study are needed.