Search Results (420)

This work investigates the impact of an internal electric field on the annihilation characteristics of positrons implanted in a $180\left(10\right)\mathrm{nm}$ SiO₂ layer of a Metal-Oxide-Silicon (MOS) capacitor, using Positron Annihilation Lifetime Spectroscopy (PALS). By varying the gate voltage, electric fields up to $1.72\mathrm{MV}/\mathrm{cm}$ were applied. The measurements reveal a field-dependent suppression of positronium (Ps) formation by up to $64\%$, leading to an enhancement of free positron annihilation. The increase in free positrons suggests that vacancy clusters are the dominant defect type in the oxide layer. Additionally, drift towards the SiO₂/Si interface reveals not only larger void-like defects but also a distinct population of smaller traps that are less prominent when drifting to the Al/SiO₂ interface. In total, by combining positron drift with PALS, more detailed insights into the nature and spatial distribution of defects within the SiO₂ network and in particular near the SiO₂/Si interface are obtained. Full article

The use of implants in the trachea is increasing in respiratory diseases as an alternative to address pathological problems with airway obstruction. This article presents the design and development of a three-way cannula and its evaluation in a testbed capable of emulating the human breathing cycle. The new tracheal cannula allows airflow through a third duct (vertical one) towards the vocal folds, enabling phonation. The testbed assesses Total Lung Capacity (TLC) and endotracheal pressure by considering the cannula inside a replica of a trachea. The flow is generated by a mechanism composed of electronic elements, and the implementation of instruments for measuring pressure and lung capacity enables the visual and continuous collection of data. The three-way cannula offers improvements in airway capacity, with an average of up to 1.766 L of airflow and a pressure of 17.083 mbar. The airflow at the upper branch allows for improvement, enabling the patient to phonate even with the implant in place, while preserving patency due to the biocompatibility and elasticity of platinum silicone. Full article

Implantable cardiac devices are critical in improving patients’ quality of life through precise and continuous interaction between the device and pathological cardiac tissue. Due to the inherently rigid nature of conventional devices, several complications arise when interacting with soft cardiac tissue, caused by a mechanical mismatch between the device and myocardium. This leads to the excessive formation of fibrous tissue around the implanted device, ultimately compromising both device functionality and tissue health. To address these challenges, flexible electronics based on polymers and elastomers significantly softer than conventional rigid metals and silicon have been explored. The epicardial approach enables the device to conform to the curved myocardial surface and deform synchronously with cardiac motion, thereby improving mechanical compatibility. However, modulus mismatches between soft polymers and cardiac tissue can still lead to mechanical instability and non-uniform adhesion, potentially affecting long-term performance. This review comprehensively summarizes recent research advancements in epicardial patch electronics based on bioadhesive and conductive hydrogels. We emphasize current research directions, highlighting the potential of hydrogels in epicardial electronics applications. Critical discussion includes recent trends, ongoing challenges, and emerging strategies aimed at improving the properties of hydrogel-based epicardial patches. Future research directions to facilitate clinical translation are also outlined. Full article

Background: This study aimed to evaluate the influence of a screw coating on the screw preload and removal torque value (RTV) with and without the application of a cyclic load (CL) to make screws with greater untightening resistance to prevent screw loosening. Methods: Ninety complexes composed of implants, abutments, and prosthetic screws were examined and tested under CL oral conditions (n = 45) and non-CL conditions (nCL, n = 45). Each group was divided into three subgroups (n = 15): a control group (CG) without a screw coating, a GapSeal^®-coated screw group (GG), and a polytetrafluoroethylene (PTFE) tape-wrapped screw group (PG). All screws were tightened at 30 Ncm, and the preload was recorded. In the nCL group, the screws were untightened to record the RTV. In the CL group, the screws were tightened, subjected to a CL in distillated water at a temperature of 37 °C, and then untightened to record the RTV. Micro-Ct analysis was conducted on two samples from each group before CL. SEM analyses of two samples per subgroup before and after CL were also performed. Results: The preload in the PG was significantly lower under nCL (29.92 Ncm) compared with CG (30.95 Ncm) and GG (31.19 Ncm) and also under a CL (PG: 30.92 Ncm) compared with CG (31.72 Ncm) and GG (31.42 Ncm). The RTVs of the PG were significantly lower under nCL (15.30 Ncm) compared with CG (27.98 Ncm) and GG (28.46 Ncm). Under CL, the RTVs of the PG were significantly higher (31.50 Ncm) compared with CG (26.00 Ncm) and GG (27.44 Ncm). Conclusions: Wrapping the screw with PTFE tape significantly reduced the preload but resulted in a significantly greater RTV under CL conditions in the simulated oral environment, suggesting that this could be a solution to decrease the risk of screw loosening. Full article

Plasma, an ionized gas composed of charged particles, has shown therapeutic potential in enhancing biological processes such as wound healing and tissue integration. Implants, such as silicone and human acellular dermal matrix (hADM), are commonly used in reconstructive surgery, but improving their biocompatibility and integration remains a challenge. This study investigated the effects of vacuum plasma treatment on silicone and hADM implants using an in vivo rat model. Plasma-treated and untreated implants were inserted subcutaneously, and tissue samples were collected at 1, 4, and 8 weeks post-implantation. Histological and immunohistochemical analyses were performed to assess inflammation, cellular infiltration, collagen formation (neocollagenesis), and angiogenesis. Results showed that plasma-treated silicone and hADM implants had significantly reduced capsule thickness at weeks 4 and 8 compared to untreated controls, indicating a lower chronic inflammatory response. Plasma treatment also promoted greater fibroblast infiltration and enhanced neocollagenesis within the hADM implants. Furthermore, immunohistochemical staining revealed a notable increase in blood vessel formation around and within the plasma-treated hADM implants, suggesting improved vascularization. In conclusion, vacuum plasma treatment enhances the biocompatibility and tissue integration of implants by reducing inflammation and promoting cellular and vascular responses, offering promising potential for improving outcomes in reconstructive surgery. Full article

Background: Silicone breast implants have been linked to autoimmune/inflammatory syndrome induced by adjuvants (ASIA). This study evaluates the role of ^99mTc-HYNIC-TOC somatostatin receptor scintigraphy in assessing somatostatin-mediated inflammation and the impact of explantation on inflammatory activity. Methods: Fifty patients with silicone breast implants and symptoms suggestive of ASIA were evaluated. Pre- and postexplantation imaging was performed using ^99mTc-HYNIC-TOC scintigraphy. Matthews correlation coefficients quantified associations between clinical symptoms and imaging findings, and autoantibody profiles were analysed. Results: Scintigraphy identified a significant uptake in organs associated with autoimmune symptoms, particularly joints and salivary glands. Strong correlations were found between imaging findings and symptoms, including knee pain (MCC = 0.81) and sicca syndrome (MCC = 0.96). Explantation resolved abnormal uptake in the surgical bed, though variable uptake persisted in other organs, reflecting systemic inflammatory heterogeneity. Autoantibody analysis revealed positivity in 66% of patients, with antinuclear antibodies being most frequent (30%). Conclusions: ^99mTc-HYNIC-TOC scintigraphy effectively evaluates organ-specific inflammation in ASIA. Explantation reduces localized inflammation but does not consistently address systemic autoimmune responses. Larger prospective studies are needed to validate these findings and improve management strategies for ASIA. Full article

Many kinds of silicones are a wide family of hybrid inorganic–organic polymers which have valuable physical and chemical properties and find plenty of practical applications, not only industrial, but also numerous medical and pharmaceutical ones, mainly due to their good thermal and chemical stability, hydrophobicity, low surface tension, biocompatibility, and bio-durability. The important biomedical applications of silicones include drains, shunts, and catheters, used for medical treatment and short-term implants; inserts and implants to replace various body parts; treatment, assembly, and coating of various medical devices; breast and aesthetic implants; specialty contact lenses; and components of cosmetics, drugs, and drug delivery systems. The most important achievements concerning the biomedical and pharmaceutical applications of silicones, their copolymers and blends, and also silanes and low-molecular-weight siloxanes have been summarized and updated. The main physiological properties of organosilicon compounds and silicones, and the methods of antimicrobial protection of silicone implants, have also been described and discussed. The toxicity of silicones, the negative effects of breast implants, and the environmental effects of silicone-containing personal care and cosmetic products have been reported and analyzed. Important examples of the 3D printing of silicone elastomers for biomedical applications have been presented as well. Full article

Mg–Zn–Mn-based biocomposites hold prospects as potential orthopedic material. The composition of these composites can be modulated, based on applications, by selective elemental alloying. Towards that, the addition of silicon (Si), hydroxyapatite (HA), or both is considered, followed by the consolidation method, such as spark plasma sintering (SPS). In this study, the micro-mechanical properties of Mg–Zn–Mn–(Si–HA) composites were investigated through the micro-pillar compression method. The effect of Si and HA incorporation on the mechanical characteristics and deformation mechanism was also elucidated. The microstructure of the composite presents porosity, together with different bioactive phases, such as Mg–Zn, CaMg, Mn–P, MgSi₂, Mn–Si, Mn–CaO, CaMgSi, and Ca–Mn–O. Such porous structures were determined to facilitate cell growth when used as an implant, particularly for musculoskeletal-related disabilities. The yield stress (YS) and compressive stress of the Mg–Zn–Mn–Si–HA were about 1543 ± 99 MPa and 1825 ± 102 MPa, respectively. These values were about 5.8 and 4.8 times higher, respectively, than those of Mg–Zn–Mn–HA composites (266 ± 42 MPa and 380 ± 10 MPa, respectively), and the same was observed for the elastic modulus. Besides that, alloying with HA and Si alters the deformation mechanism from brittle (for Mg–Zn–Mn–Si composites) or ductile (for Mg–Zn–Mn–HA composites) to predominant ductile failure without compromising the attained mechanical properties. Full article

With the evolution of synchrotron light sources to fourth generation (diffraction-limited storage rings), the brilliance is increased by several orders of magnitude compared to third generation facilities. For example, the Swiss Light Source (SLS) has been upgraded to SLS 2.0, promising a horizontal emittance reduced by a factor of 40, and a brilliance up to two orders of magnitude (three at higher energies). A key challenge arising from the increased flux is the heightened accumulated dose in silicon sensors, which leads to a significant increase in radiation damage. This translates into an increase of both noise and dark current, as well as a reduction in the dynamic range for long exposure times, thus affecting the performance of the detector, in particular, for charge-integrating detectors. We have designed sensors with a 4 × 4 mm² pixel array featuring 16 design variations of 25 µm pitch pixels with different implant and metal sizes and tested them bump-bonded to MÖNCH 0.3, a charge integrating hybrid pixel detector readout ASIC. Following a first assessment of the functionality and performance of the different pixel designs, the assembly has been irradiated with X-rays. The variation in the tested parameters was characterized at different accumulated doses up to 100 kGy at the sensor entrance window side. The annealing dynamics at room temperature have also been measured. The results show that the default pixel design is currently not optimal and can benefit from layout changes (reduction in the inter-pixel gap area with full metal coverage of the implant). Further studies on the metal coverage over large implants could be conducted. The layout changes are, however, not sufficient for future full-sized sensors, requiring improved radiation hardness and long-term stability, and additional strategies such as focusing on detector cooling and changes in sensor technologies would be required. Full article

Background: Hallux rigidus is a painful and degenerative pathology of the first metatarsophalangeal (MTP1) joint. In severe cases it is usually appropriate to consider arthrodesis or arthroplasty of the joint. Arthrodesis represents the gold standard, but arthroplasty allows patients to recover mobility. Although arthroplasty has slightly inferior functional results to arthrodesis, it has shown very good results in terms of joint mobility, patient satisfaction and pain reduction. The goal of the present study was to evaluate short-term outcomes of patients that received a third-generation double-stemmed MTP1 implant manufactured from high-performance silicon. Methods: In this retrospective study the authors analyzed data of 37 patients who underwent MPT1 joint arthroplasty with Silktoe^TM double-stemmed implant using the R 4.2.2 software (R Foundation for Statistical Computing, Vienna, Austria). The indications were hallux rigidus of grade III and grade IV (81.1%), hallux rigidus plus valgus (10.8%), painful or unstable joint following previous surgery (5.4%) and hallux rigidus due to gout (2.7%). Data were collected during routine visits at 1 and 6 months and 1 and 2 years. Results: There were no intraoperative and postoperative complications. There were no revisions or reoperations at a follow-up of two years. The American Orthopaedic Foot and Ankle Society-Hallux Metatarsophalangeal-Interphalangeal Scale (AOFAS-HMI) score was 94.6 ± 7.6 (median, 100; range, 70–100) and the Visual Analogue Scale (VAS) score was 0.4 ± 0.80 (median, 0; range, 0–3.5) at the final follow-up. Conclusions: The data from this study presented excellent short-term results for patients who received an arthroplasty of the MTP1 joint using a third-generation double-stemmed spacer made of high-performance silicone. For all patients who received the Silktoe^TM implant, AOFAS-HMI scores of 94.6 and VAS scores of 0.4 were obtained at a two-year follow-up. These values were in line with results reported in the literature for similar devices. Full article

This review provides an overview of defects in silicon carbide (SiC) with potential applications as quantum qubits. It begins with a brief introduction to quantum qubits and existing qubit platforms, outlining the essential criteria a defect must meet to function as a viable qubit. The focus then shifts to the most promising defects in SiC, notably the silicon vacancy (V_Si) and divacancy (V_C-V_Si). A key challenge in utilizing these defects for quantum applications is their precise and controllable creation. Various fabrication techniques, including irradiation, ion implantation, femtosecond laser processing, and focused ion beam methods, have been explored to create these defects. Designed as a beginner-friendly resource, this review aims to support early-career experimental researchers entering the field of SiC-related quantum qubits. Providing an introduction to defect-based qubits in SiC offers valuable insights into fabrication strategies, recent progress, and the challenges that lie ahead. Full article

The integration of multi-source energy harvesting (EH) systems into silicon presents a promising avenue for powering autonomous, low-power devices, particularly in applications such as the Internet of Things (IoT), biomedical implants, and wireless sensor networks, where power efficiency and small-size solutions are crucial. This review provides a detailed technical assessment of energy harvesting schemes—including photovoltaic, mechanical, thermoelectric, and radio frequency energy harvesting—and the integration of their associated electronic circuits into silicon integrated solutions. The EH systems are critically analyzed based on their architectures, the number and type of input sources, and key performance metrics such as energy conversion efficiency, output power delivered to loads, silicon area footprint, and degree of integration (e.g., reliance on external components). By examining current advancements and practical implementations, crucial design parameters are assessed for state-of-the-art integrated silicon energy harvesting systems. Furthermore, based on current trends, future research directions are outlined to enhance EH efficiency, reliability, and scalability, paving the way for fully integrated silicon-based EH systems for the next-generation self-powered electronic devices. Full article

Mammalian tissues and cells often orient naturally in specific patterns to function effectively. This cellular alignment is influenced by the chemical nature and topographic features of the extracellular matrix. In implants, a range of different materials have been used in vivo. Of those, tantalum and its alloys are promising materials, especially in orthopedic implant applications. Previous studies have demonstrated that nano- and micro-scale surface features, such as symmetric comb structures, can significantly affect cell behavior and alignment. However, patterning need not be restricted to symmetric geometries, and there remains a gap in knowledge regarding how cells respond to asymmetric comb structures, where the widths of the trenches and lines in the comb differ. This study aims to address this gap by examining how Vero cells (cells derived from an African green monkey) respond when applied to tantalum and tantalum/silicon oxide asymmetric comb structures having fixed trench widths of 1 μm and line widths ranging from 3 μm to 50 μm. We also look at the cell responses on inverted patterns, where the line widths were fixed at 1 μm while trench widths varied. The orientation and morphology of the adherent cells were analyzed using fluorescence confocal microscopy and scanning electron microscopy. Our results indicate that the widths of the trenches and lines are important design parameters influencing cell behavior on asymmetric comb structures. Furthermore, the ability to manipulate cell morphology using these structures decreased when parts of the tantalum lines were replaced with silicon oxide. Full article

This paper presents a study of microstructure formation in bioresorbable Fe-Mn-Si alloys for temporary implants under high-pressure torsion (HPT) at room temperature and at 300 °C. The effect of silicon on the mechanism of microstructure formation under HPT and, as a consequence, on the mechanical, corrosion and biological properties of the alloys is studied. It is established that Si promotes martensitic transformation. HPT leads to an increase in the microhardness values of the studied alloys from ~1560 MPa in the initial state to ~5500 MPa (160–560 HV) due to structure refinement and phase transformation. An increase in the electrochemical corrosion rate of Fe-Mn-Si alloys to ~0.5 mm/year is established due to grain refinement to nanosize and the formation of strain-induced martensite. In vitro cytotoxicity and induced hemolysis studies showed that Fe-Mn, Fe-Mn-3.7Si, and Fe-Mn-5Si alloys after annealing and HPT can be characterized as biocompatible. Full article

Laser annealing plays a significant role in the fabrication of scaled-down semiconductor devices by activating dopant ions and rearranging silicon atoms in ion-implanted silicon wafers, thereby improving material properties. Precise temperature control is crucial in wafer annealing, particularly for repeated processes where repeatability affects uniformity. In this study, we employ a three-dimensional time-dependent thermal simulation model to numerically analyze the multiple static laser annealing processes based on a CO₂ laser with a center wavelength of 9.3 μm and a pulse repetition rate of 10 kHz. The heat transfer equation is solved using a multiphysics coupling approach to accurately simulate the effects of different numbers of CO₂ laser pulses on wafer temperature rise and repeatability. Additionally, a pyrometer is used to collect and convert the surface temperature of the wafer. Radiation intensity is converted to temperature via Planck’s law for real-time monitoring. Post-processing is performed to fit the measured temperature and the actual temperature into a linear relationship, aiding in obtaining the actual temperature under small beam spots. According to the simulation conditions, a wafer annealing device using a CO₂ laser as the light source was independently built for verification, and a stable and uniform annealing effect was realized. Full article