A case report of squamous cell carcinoma mimicking interdigital intertrigo.

Squamous cell carcinoma (SCC), also known as epidermoid carcinoma, represents the most common malignant tumor affecting the nails. A 60-year-old tailor with no significant medical history presented with a three-year history of macerated skin between the toes, previously treated with a topical antifungal. Dermatological examination revealed a verrucous, infected ulceration with infiltrated and hyperkeratotic edges, characterized by a whitish, fissured base. This lesion in the fourth interdigital space and extended onto the dorsal surface of the foot without any other associated symptoms. The clinical diagnosis identified it as a neoplastic ulceration. An initial biopsy found keratoacanthoma but showed no malignant features. However, follow-up biopsy at our department revealed moderately differentiated SCC. Surgical resection was successful in treating our patient. Diagnostic errors due to insufficient understanding of the pathology and inadequate biopsy methods contribute to the progression of SCC. Surgery is the main treatment for such malignant tumors.

Circular SAW Resonators: Influence of Sensitive Element Dimensions on Strength Characteristics and First Experimental Samples.

In preceding research endeavors, the frequency characteristics of a ring resonator on surface acoustic waves made of various materials were studied. Investigations encompassed fixation techniques within the housing, the impact of external variables on these components, and the most efficient configuration of the interdigital transducer within the ring resonator to curtail bandwidth. This current study is dedicated to investigating the correlation between sensitivity and the highest measurable acceleration concerning the dimensions of these sensitive elements. Furthermore, it involves assessing the attributes of produced experimental samples to verify the simulation results. The results obtained represent the possibility of creating a micromechanical accelerometer that can be used in the automotive industry as a g-sensor shock, as well as in industries where the numerical value of high overloads is required.

Validation of the hind feet position score and its association with heel height difference in dairy cows.

Hind feet position scoring (HFPS) categorizes the outward rotation of the hind feet from the line parallel to the midline of the body in standing dairy cows. It has previously been used as an indication of both differences in heel height between the lateral and medial hind claw (to determine the need of hoof trimming) and the presence of claw lesions in sound cattle. In this observational study, the agreement of HFPS with other types of hoof angle measurements, as well as its association with the heel height difference (HHD) between the claws were investigated.A total of 51 dairy cows were assessed independently by three observers in two measuring rounds on two different measuring days each. On each occasion, they scored the HFPS, and measured the angle of outward rotation of both hind feet using a digital protractor (DIG) and a compass app (COMP). Heel height difference was measured only during the second occasion. Intra- and interobserver agreement were calculated using weighted kappa statistics (HFPS) and intraclass correlation (DIG, COMP and HHD). Associations between HFPS and DIG, COMP and HHD were analyzed using linear mixed models.Intra- and interobserver reliability were poor to good for HFPS, DIG, COMP and HHD. HFPS was significantly associated with DIG and COMP but not with HHD. Using the median value of repeated HFPS scores could increase the robustness of the HFPS assessment, as our data indicate that the cows frequently shift the position of their hind claws. Overall, there was a poor correlation between HHD and HFPS, so HFPS may not be determined by HHD alone; future research should consider other reasons for outward rotation of the hind feet.

Flexible, Wearable Wireless-Charging Power System Incorporating Piezo-Ultrasonic Arrays and MXene-Based Solid-State Supercapacitors.

With the continuous development of wearable electronics, higher requirements are put forward for flexible, detachable, stable output, and long service life power modules. Given the limited capacity of energy storage devices, the integration of energy capture and storage is a viable approach. Here, we present a flexible, wearable, wireless-charging power system that integrates a piezoelectric ultrasonic array harvester (PUAH) with MXene-based solid-state supercapacitors (MSSSs) in a soft wristband format for sustainable applications. The MSSS as the energy storage module is developed by using Ti3C2Tx nanosheet-loaded inserted finger-like carbon cloth skeletons as electrodes and poly(vinyl alcohol)/H3PO4 gel as electrolytes, with high energy density (58.74 Wh kg-1) and long cycle life (99.37%, 10,000 cycles). A two-dimensional stretchable piezoelectric array as a wireless-charging module hybridizes high-performance 1-3 composite units with serpentine electrodes, which allows wireless power via ultrasonic waves, with a maximum power density of 1.56 W cm-2 and an output voltage of 20.75 V. The overall PUAH-MSSS wireless energy supply system is 2 mm thick and offers excellent energy conversion/storage performance, cyclic stability, and mechanical flexibility. The results of this project will lay the foundation for the development of next-generation wearable electronics.

Study of Risk Factors for the Presence of Interdigital Nevi of the Feet. / Estudio de los factores de riesgo de la presencia de los nevus interdigitales de los pies.

BACKGROUND AND OBJECTIVES: No studies focused on counting the interdigital acquired melanocytic nevi (AMN) of the foot (IDNf) have ever been conducted. Therefore, our objective was to study the relationship between the presence of IDNf and the total number of AMN in the feet and the rest of the body, the racial phenotypic characteristics, and other risk factors for melanoma. MATERIAL AND METHODS: We conducted a cross-sectional observational study with 255 patients ≥18 years old who attended our Dermatology Unit from September 2020 through February 2021, and included all AMN ≥1mm from the feet and ≥2mm from the rest of the bod. The association between the variables was studied using univariate and multivariate logistic regression models. RESULTS: The presence of IDNf was significantly and independently associated with the presence of plantar AMN and body counts ≥50 AMN. However, no significant differences were observed regarding sex, age, personal history of melanoma, presence of nevi on the dorsum of the foot, history of sunburn or UV rays, or racial phenotypic characteristics. CONCLUSIONS: The presence of IDNf is associated with a higher count of plantar nevi and total AMN in the body, meaning that interdigital spaces of the foot-anatomical expansions of the sole and other possibly genetic causes-could be responsible for the number of AMN found in this location, as these regions are not photoexposed.

The construction of canine distal limb models used in teaching sonography identification of vegetal foreign bodies.

Musculoskeletal ultrasonography is a useful tool to identify radiolucent vegetal foreign bodies (VFBs). However, limited ultrasound experience and unfamiliarity with the normal sonographic appearance of anatomical structures can decrease clinician confidence. This study aimed to design a reusable silicone model that can teach VFB identification within the canine distal limb. Four canine hindlimbs were used to design the silicone models, and 12 canine distal forelimbs were constructed. The model was constructed using cadaver bones, barley grass (Avena fatua) seeds, and silicone to mimic the anatomy of the canine distal limb with a grass seed VFB. Limbs were randomly grouped based on grass seed locations: (1) the interdigital webbing, (2) the palmar surface of the canine forelimb immediately proximal to the metacarpal pad, (3) the dorsal surface of the distal limb immediately proximal to the proximal phalange, or (4) no grass seed (control) placed. Each limb was systematically ultrasounded and compared with cadaver limbs and clinical VFB cases. A comparison of ultrasonographic images validated the construction, revealing that the simulation model replicates the anatomical and echotexture characteristics of the normal canine distal limb. Furthermore, these models also have a likeness to clinical canine distal limb VFB cases and can be utilized as a training tool.

Interdigital-type antifungal socks for prevention and treatment of tinea pedis.

BACKGROUND: Interdigital tinea pedis is the most common type of foot infection, which is often treated by topical or systemic antifungals. Due to the increase in antifungal resistance, antifungal socks are becoming potential alternatives for the daily management of tinea pedis. METHODS: In this study, antifungal fibres were adopted to produce interdigital hygiene socks to split the third and fourth toe seams of the feet. In vitro antifungal activity was first examined to verify the effectiveness of the socks. Preventive efficacy against tinea pedis was then evaluated among healthy participants, followed by therapeutic effect detection in patients diagnosed with tinea pedis by analysing the improvement in total symptom scores (TTS). RESULTS: The interdigital-type hygiene socks exhibited apparent antifungal activities in vitro. An in vivo study demonstrated significant preventive effects against tinea pedis for interdigital socks compared to plain socks (P = 0.011) and a lower TTS than noninterdigital (P = 0.04) or plain socks (P < 0.0001). Moreover, interdigital socks showed a total effectiveness rate of 72.9% in patients with tinea pedis, with most of the symptoms alleviated. CONCLUSION: Interdigital-type hygiene socks not only exhibited in vitro antifungal activities but also showed significant prophylactic and therapeutic effects against interdigital tinea pedis in vivo.

An Improved Method to Compute the Mutual Capacitance between Interdigital Transducers in Radio Frequency Surface Acoustic Wave Filters.

This paper proposes an improved method to calculate the mutual capacitance between interdigital transducer (IDT) electrodes to enhance the accuracy of the traditional coupling-of-modes (COM) model, which is commonly used to simulate surface acoustic wave (SAW) filters and duplexers. In this method, the boundary element method (BEM) is adopted to obtain the capacitance per unit length in a layered medium, while the partial capacitance (PC) method is used to derive the effective relative permittivity of the multi-layered IDT. Numerical results from commercially available software are provided for comparison with the results calculated using the proposed method. The consistent results verify the validity and accuracy of this method, which also demonstrates significantly faster calculation speed compared to commercially available software. Precise electrical response prediction of a dual-mode SAW (DMS) filter can be achieved by applying this method to the COM model, and this ultra-fast calculation method can also be included in filter design optimization.

Influence of DNA-methylation at multiple stages of limb chondrogenesis.

Precise regulation of gene expression is of utmost importance during cell fate specification. DNA methylation is a key epigenetic mechanism that plays a significant role in the regulation of cell fate by recruiting repression proteins or inhibiting the binding of transcription factors to DNA to regulate gene expression. Limb development is a well-established model for understanding cell fate decisions, and the formation of skeletal elements is coordinated through a sequence of events that control chondrogenesis spatiotemporally. It has been established that epigenetic control participates in cartilage maturation. However, further investigation is required to determine its role in the earliest stages of chondrocyte differentiation. This study investigates how the DNA methylation environment affects cell fate divergence during the early chondrogenic events. Our research has shown for the first time that inhibiting DNA methylation in interdigital tissue with 5-azacytidine results in the formation of an ectopic digit. This discovery suggested that DNA methylation dynamics could regulate the fate of cells between chondrogenesis and cell death during autopod development. Our in vitro findings indicate that DNA methylation at the early stages of chondrogenesis is integral in regulating condensation by controlling cell adhesion and proapoptotic genes. As a result, the dynamics of methylation and demethylation are crucial in governing chondrogenesis and cell death during different stages of limb chondrogenesis.

Detection of a Submillimeter Notch-Type Defect at Multiple Orientations by a Lamb Wave A0 Mode at 550 kHz for Long-Range Structural Health Monitoring Applications.

The early detection of small cracks in large metal structures is a crucial requirement for the implementation of a structural health monitoring (SHM) system with a low transducers density. This work tackles the challenging problem of the early detection of submillimeter notch-type defects with a semielliptical shape and a groove at a constant width of 100 µm and 3 mm depth in a 4.1 mm thick aluminum plate. This defect is investigated with an ultrasonic guided wave (UGW) A0 mode at 550 kHz to investigate the long range in thick metal plates. The mode selection is obtained by interdigital transducers (IDTs) designed to operate with a 5 mm central wavelength. The novel contribution is the validation of the detection by pulse-echo and pitch and catch with UGW transducers to cover a distance up to 70 cm to reduce the transducers density. The analysis of scattering from this submillimeter defect at different orientations is carried out using simulations with a Finite Element Model (FEM). The detection of the defect is obtained by comparing the scattered signals from the defect with baseline signals of the pristine laminate. Finally, the paper shows that the simulated results are in good agreement with the experimental ones, demonstrating the possible implementation in an SHM system based on the efficient propagation of an antisymmetric mode by IDTs.

Recent Progress in Flexible Surface Acoustic Wave Sensing Technologies.

In this work, the major methods for implementing flexible sensing technology-flexible surface acoustic wave (SAW) sensors-are summarized; the working principles and device characteristics of the flexible SAW sensors are introduced; and the latest achievements of the flexible SAW sensors in the selection of the substrate materials, the development of the piezoelectric thin films, and the structural design of the interdigital transducers are discussed. This paper focuses on analyzing the research status of physical flexible SAW sensors such as temperature, humidity, and ultraviolet radiation, including the sensing mechanism, bending strain performance, device performance parameters, advantages and disadvantages, etc. It also looks forward to the development of future chemical flexible SAW sensors for gases, the optimization of the direction of the overall device design, and systematic research on acoustic sensing theory under strain. This will enable the manufacturing of multifunctional and diverse sensors that better meet human needs.

A low-voltage alternant direct current electroporation chip for ultrafast releasing the genome DNA of Helicobacter pylori bacterium.

Nucleic acid detection, as an important molecular diagnostic method, is widely used in bacterial identification, disease diagnosis. For detecting the nucleic acid of bacteria, the prerequisite is to release nucleic acids inside the bacteria. The common means to release nucleic acids is the chemical method, which involves complex processes, is time-consuming, and remains chemical inhibitors. Compared with chemical methods, electroporation as a physical method has the advantages of easy operation, short-time consumption, and chemical reagents free. However, the current works using electroporation often necessitates high-frequency or high-voltage conditions, entailing bulky power devices. Herein, we propose a low-voltage alternant direct current (LADC) electroporation chip and the corresponding miniature device for ultrafast releasing the genome DNA from Helicobacter pylori (H. pylori) for detection. We connected a micrometer-interdigital electrode in the chip with a 20 V portable battery to make the miniature device. Using this low-voltage device, our chip released genome DNA of H. pylori within only 5 ms, achieving a cell lysis rate of 99.5%. We further combined this chip with a colorimetric loop-mediated isothermal amplification assay to visually detect H. pylori within ~ 25 min at 10 CFU/µL. We detected 11 clinical samples using the chip, and the detection results were consistent with those of the clinical standard. The results indicate that the LADC electroporation chip is useful for ultrafast release of genome DNA from bacteria and is expected to promote the development of nucleic acid detection in POCT and other scenarios.

Surface acoustic wave actuated plasmonic signal amplification in a plasmonic waveguide.

Enhancement of nanoscale confinement in the subwavelength waveguide is a concern for advancing future photonic interconnects. Rigorous innovation of plasmonic waveguide-based structure is crucial in designing a reliable on-chip optical waveguide beyond the diffraction limit. Despite several structural modifications and architectural improvements, the plasmonic waveguide technology is far from reaching its maximum potential for mass-scale applications due to persistence issues such as insufficient confined energy and short propagation length. This work proposes a new method to amplify the propagating plasmons through an external on-chip surface acoustic signal. The gold-silicon dioxide (Au-SiO2) interface, over Lithium Niobate (LN) substrate, is used to excite propagating surface plasmons. The voltage-varying surface acoustic wave (SAW) can tune the plasmonic confinement to a desired signal energy level, enhancing and modulating the plasmonic intensity. From our experimental results, we can increase the plasmonic intensity gain of 1.08 dB by providing an external excitation in the form of SAW at a peak-to-peak potential swing of 3 V, utilizing a single chip.

Enhancing Performance of GaN/Ga2 O3 P-N Junction Uvc Photodetectors via Interdigitated Structure.

Ga2 O3 -based Ultraviolet-C photodetector (UVCPD) is considered the most promising UVCPD at present and is divided into Metal-Semiconductor-Metal (MSM) and PN junction types. Compared with MSM-PDs, PN-PDs exhibit superior transient performance due to the built-in electric field. However, current Ga2 O3 -based PN-PDs lack consideration for carrier collection and electric field distribution. In this study, PN-PDs with an interdigital n-Ga2 O3 layer and finger electrodes are fabricated on p-GaN/n-Ga2 O3 epilayers. Ultrafast response times of 31 µs (1/e decay) and 2.76 µs (fast component) are realized, which outperforms all Ga2 O3 UVC-PDs up to now. Under 0 V self-powered, the responsivity (0.25 A W-1 ) of interdigital PD is enhanced by the interdigital electrode structure due to increasing carriers' collection length. Under bias, the performances of interdigital PD with 41.7 A W-1 responsivity and 8243 selection ratios are significantly elevated by enhancing the built-in electric field in the Ga2 O3 region, which is 34.76 and 39.4 times those of traditional PDs, respectively. The intrinsic enhancing mechanism of interdigital structure is also investigated by interdigital PDs with various electrode spacings and perimeters. In summary, this paper not only reports a highly performed interdigitated structure p-GaN/n-Ga2 O3 UVCPDs, but also provides guidelines for structure design in Ga2 O3 -based PN-PDs.

Microstructured Gel Polymer Electrolyte and an Interdigital Electrode-Based Iontronic Barometric Pressure Sensor with High Resolution over a Broad Range.

We present a novel iontronic barometric pressure sensor based on a gel polymer electrolyte and interdigital electrodes with a much simpler structure than that of existing devices. By introducing high-density microstructures on the gel polymer electrolyte and one side electrode arrangement configuration, the developed sensor offers high performances with an ultrahigh resolution of 10 Pa, an ultrawide barometric pressure-response range from -92 to 7 kPa, a fast response time of ∼15 ms, and excellent long-term stability. The single pressure sensor is able to detect positive and negative barometric pressures without needing any additional means and can operate as a barometric altimeter with a resolution of about one-floor height. The performances of the sensors significantly surpass those of existing barometric pressure sensors. This work provides a new strategy for making high-performance barometric pressure sensors that are highly sought for commercial applications such as altitude detection, negative pressure ambulance, and consumer electronics.

Designed Structures of Interdigital Electrodes for Thin Film SAW Devices.

This paper studied the impact of the microstructure of interdigital electrodes on the performance of surface acoustic wave (SAW) resonators and proposed an innovative piston, dummy finger and tilt (PDT) structure, which was then applied to the GLONASS L3 band filters. Through the adoption of 3D finite element simulation (FEM), photolithography, and testing on an incredible high-performance surface acoustic wave (I.H.P. SAW) substrate, it is concluded that the total aperture length is 20T (T is period), resulting in a more optimal resonator performance; changing the width and length of the piston can suppress transverse modes spurious, but it does not enhance impedance ratio; to further improve the quality of the SAW resonator, the proposed PDT structure has been experimentally proven to not only effectively suppress transverse modes spurious but also possess a high impedance ratio. By utilizing a PDT structure within a "T + π" topology circuit, we successfully designed and manufactured a GLONASS L3 band filter with a bandwidth of 8 MHz and an insertion loss of 3.73 dB. The design of these resonators and filters can be applied to the construction of SAW filters in similar frequency bands such as BeiDou B2 band or GPS L2/L5 band.

Electrical stimulation induces anti-tumor immunomodulation via a flexible microneedle-array-integrated interdigital electrode.

Immunotherapy has revolutionized cancer therapy, using chemical or biological agents to reinvigorate the immune system. However, most of these agents have poor tumor penetration and inevitable side effects that complicate therapeutic outcomes. Electrical stimulation (ES) is a promising alternative therapy against cancers that does not involve chemical or biological agents but is limited in the fabrication and operation of complex micrometer-scale ES devices. Here, we present an optically microprinted flexible interdigital electrode with a gold-plated polymer microneedle array to generate alternating electric fields for cancer treatment. A flexible microneedle-array-integrated interdigital electrode (FMIE) was fabricated by combining optical 3D microprinting and electroless plating processes. FMIE-mediated ES of cancer cells induced necrotic cell death through mitochondrial Ca2+ overload and increased intracellular reactive oxygen species (ROS) production. This led to the release of damage-associated molecular patterns that activated the immune response and potentiated immunogenic cell death (ICD). FMIE-based ES has an excellent safety profile and systemic anti-tumor effects, inhibiting the growth of primary and distant tumors as well as melanoma lung metastasis. FMIE-based ES-driven cancer immunomodulation provides a new pathway for drug-free cancer therapy.

Ultra-Compact Low-Pass Spoof Surface Plasmon Polariton Filter Based on Interdigital Structure.

An ultra-compact low-pass spoof surface plasmon polariton (SSPP) filter based on an interdigital structure (IS) is designed. Simulated dispersion curves show that adding the interdigital structure in an SSPP unit effectively reduces its asymptotic frequency compared with traditional and T-shaped SSPP geometries, and the unit dimensions can be conversely reduced. Based on that, three IS-based SSPP units are, respectively, designed with different maximum intrinsic frequencies and similar asymptotic frequencies to constitute the matching and waveguide sections of the proposed filter, and the unit number in the waveguide section is adjusted to improve the out-of-band suppression. Simulation results illustrate the efficient transmission in the 0~5.66 GHz passband, excellent out-of-band suppression (over 24 dB) in the 5.95~12 GHz stopband and ultra-shape roll-off at 5.74 GHz of the proposed filter. Measurement results on a fabricated prototype validate the design, with a measured cut-off frequency of 5.53 GHz and an ultra-compact geometry of 0.5 × 0.16 λ02.

Humidity Sensor Composed of Laser-Induced Graphene Electrode and Graphene Oxide for Monitoring Respiration and Skin Moisture.

Respiratory rate and skin humidity are important physiological signals and have become an important basis for disease diagnosis, and they can be monitored by humidity sensors. However, it is difficult to employ high-quality humidity sensors on a broad scale due to their high cost and complex fabrication. Here, we propose a reliable, convenient, and efficient method to mass-produce humidity sensors. A capacitive humidity sensor is obtained by ablating a polyimide (PI) film with a picosecond laser to produce an interdigital electrode (IDE), followed by drop-casting graphene oxide (GO) as a moisture-sensitive material on the electrode. The sensor has long-time stability, a wide relative humidity (RH) detection range from 10% to 90%, and high sensitivity (3862 pF/%RH). In comparison to previous methods, the technology avoids the complex procedures and expensive costs of conventional interdigital electrode preparation. Furthermore, we discuss the effects of the electrode gap size and the amount of graphene oxide on humidity sensor performance, analyze the humidity sensing mechanism by impedance spectrum, and finally perform the monitoring of human respiratory rate and skin humidity change in a non-contact manner.

Microwave Sensor for the Determination of DMSO Concentration in Water-DMSO Binary Mixture.

This research aims to develop a microwave sensor to accurately measure the concentration of dimethyl sulfoxide (DMSO) in water-DMSO binary mixtures. The proposed sensor will utilize microwave frequency measurements to determine the DMSO concentration, providing a non-invasive and efficient method for analyzing DMSO solutions. The research will involve the design, fabrication, and testing of the sensor, as well as the development of an appropriate calibration model. The outcomes of this study will contribute to improved monitoring and quality control in various fields, including pharmaceuticals, chemical synthesis, and biomedical research. The binary mixtures of dimethyl sulfoxide (DMSO) and water with varying concentrations were investigated in the frequency range of 1 GHz to 5 GHz at room temperature using a microwave sensor. The proposed microwave sensor design was based on an interdigital capacitor (IDC) microstrip antenna loaded with a hexagonal complementary ring resonator (HCRR). The performance of the sensor, fabricated using the print circuit board (PCB) technique, was validated through simulations and experiments. The reflection coefficient (S11) and resonance frequency (Fr) of binary mixtures of DMSO and water solutions were recorded and analyzed for DMSO concentrations ranging from 0% v/v to 75% v/v. Mathematical models were developed to analyze the data, and laboratory tests showed that the sensor can detect levels of DMSO/water binary mixtures. The sensor is capable of detecting DMSO concentrations ranging from 0% v/v to 75% v/v, with a maximum sensitivity of 0.138 dB/% for S11 and ΔS11 and 0.2 MHz/% for Fr and ΔFr at a concentration of 50% v/v. The developed microwave sensor can serve as an alternative for detecting DMSO concentrations in water using a simple and cost-effective technique. This method can effectively analyze a wide range of concentrations, including highly concentrated solutions, quickly and easily.