Long-term Device Research Articles

Hyperstable low-tortuosity fast ion nanochannels for MXene electrodes

The development of flexible MXene-based electrodes with hyperstable ion nanochannels and low tortuosity, remains daunting challenging for long-term wearable electronic devices. This paper presents a hydrogen-bonding enhanced holey MXene (HC-HMXene) electrode with maximum ion accessibility, optimized ion transport pathways, and hyperstable ion nanochannels. Specifically, three roles of introducing in-plane mesopores, reducing the lateral dimensions, and increasing the interlayer spacing in HMXene film notably enhance the electrolyte permeation efficiency and shorten the ion transport paths of the electrode (resulting in a 78.7-fold decrease in tortuosity). Thus, the constructed HC-HMXene electrode exhibits 41.1 times higher diffusion coefficient and 2.3 times higher specific capacitance than those of closely restacked film electrode with the same mass loading of MXene. Furthermore, the aramid nanofibers introduced among the MXene layers as interlocking agents bond the nanosheets via hydrogen interaction and significantly enhance the stability of the ion channel. Consequently, the HC-HMXene film effectively resists swelling behavior and maintains good structural stability in aqueous media. Moreover, the flexible sensing integrated system, powered by a HC-HMXene-based zinc ion microcapacitor, exhibits promising application prospects in real-time monitoring human physiological characteristics.

Highly Durable Inverted Inorganic Perovskite/Organic Tandem Solar Cells Enabled by Multifunctional Additives.

Inverted perovskite/organic tandem solar cells (P/O TSCs) suffer from poor long-term device stability due to halide segregation in organic-inorganic hybrid wide-band gap (WBG) perovskites, which hinders their practical deployment. Therefore, developing all-inorganic WBG perovskites for incorporation into P/O TSCs is a promising strategy because of their superior stability under continuous illumination. However, these inorganic WBG perovskites also face some critical issues, including rapid crystallization, phase instability, and large energy loss, etc. To tackle these issues, two multifunctional additives based on 9,10-anthraquinone-2-sulfonic acid (AQS) are developed to regulate the perovskite crystallization by mediating the intermediate phases and suppress the halide segregation through the redox-shuttle effect. By coupling with organic cations having the desirable functional groups and dipole moments, these additives can effectively passivate the defects and adjust the alignment of interface energy levels. Consequently, a record Voc approaching 1.3 V with high power conversion efficiency (PCE) of 18.59 % could be achieved in a 1.78 eV band gap single-junction inverted all-inorganic PSC. More importantly, the P/O TSC derived from this cell demonstrates a T90 lifetime of 1000 h under continuous operation, presenting the most stable P/O TSCs reported so far.

Buried interface management for FAPbI3-based perovskite solar cells via multifunctional benzothiadiazole derivatives

Attaining high efficiency in perovskite solar cells (PSCs) often necessitates effective interfacial passivation, which poses challenges, especially concerning the buried interface due to the dissolution of passivation agents during perovskite deposition. In this work, we report a multifunctional modification strategy by introducing the variations of benzothiadiazole (BTD) derivatives to function as interface-modified layers in PSCs. This buried interface modification mitigates oxygen vacancies on the SnO2 surface and fine-tunes the energy level of the electron transport layer, resulting in an improved alignment with the FAPbI3 layer. Furthermore, the introduced BTD derivatives led to the improved crystallinity of FAPbI3 films as well as suppressed the non-radiative recombination losses through passivating the interfacial defects. Consequently, a device with modified SnO2 exhibited an enhanced power conversion efficiency (PCE) of 25.04% along with an improved long-term device stability.

7576 A Rare and Atypical Presentation of Bladder Paraganglioma in a Patient on Long-Term Left Ventricular Assist Device

Abstract Disclosure: S.D. Leungsuwan: None. S.J. Lee: None. S.D. Lim: None. L. Loh: None. Background: Paragangliomas (PGLs) are rare neuroendocrine tumors arising from chromaffin cells. Capable of producing catecholamines, functional PGLs often cause a myriad of autonomic symptoms and complications, including cardiomyopathy. We report a case of bladder PGL in a patient on Left Ventricular Assist Device (LVAD). Clinical Case: A 64-year-old Chinese Female with a history of non-ischaemic cardiomyopathy on long-term continuous LVAD and Cardiac Resynchronisation Therapy Defibrillator (CRT-D) was admitted for recurrent low LVAD flow <2 Litres per minute and labile mean arterial pressure (MAP) 57-151mmHg. She has been on long-term Nebivolol, Entresto, Hydralazine, and Sildenafil without recent dose adjustment. Workup for acute illnesses was non-contributory. 24-hour urine metanephrine and normetanephrine (NM) were 939nmol/d [normal 400-1500nmol/d] and 33883nmol/d [normal 600-1900nmol/d] respectively. Plasma free metanephrine and NM were 0.37nmol/L [normal <0.33nmol/L] and >10.00nmol/L [normal <0.99nmol/L] accordingly. A review of previous ultrasonography and Computed Tomography (CT) imaging revealed a right adnexal mass indenting the bladder which the patient formerly declined further assessment; adrenal glands were normal. FDG-PET CT was done and showed an isolated focus of increased tracer uptake corresponding with the right pelvic mass. An impression of likely bladder PGL was made. A multidisciplinary team including Cardiology, Anaesthesiology, Interventional Radiology (IR), Urology, Gynaecology, and Endocrinology was convened; the patient was recommended surgical resection of the tumor. Preoperatively, she was started on phenoxybenzamine 10mg BD and advised judicious fluid and salt intake. Nebivolol was continued while hydralazine was stopped. This achieved targets of i) MAP 70-80mmHg, ii) approximately 10mmHg MAP postural fluctuation, iii) sitting and standing heart rates 60-70 beats-per-minute (BPM) and 70-80BPM, and iv) no more than 1 PVC every 5 minutes. Two weeks later, she underwent IR-guided angioembolisation and tumor resection uneventfully. Intraoperatively, the patient had haemodynamic fluctuations requiring dynamic administrations of phentolamine, norepinephrine, epinephrine, vasopressin, glyceryl trinitrate, and sodium nitroprusside. Histopathology was consistent with PGL with intact SDH-A and SDH-B expression. Postoperatively, phenoxybenzamine was discontinued and no recurrent LVAD low flow was noted. Subsequent plans for repeat plasma metanephrines and genetic studies were made. Discussion: This case is the first to report an atypical presentation of PGL with LVAD low flow and labile blood pressure. The significant elevations of urine NM (17.8x upper normal limit) and plasma NM (>10.1x upper normal limit) also underline the concept of fold-elevations and post-test probability of PGL. Presentation: 6/3/2024

Reusable gallium-based electrochemical sensor for efficient glucose detection

Among wearable sensing devices, electrochemical sensors are overwhelming in biochemical detection due to their simple design but high sensitivity. Most electrochemical sensors are disposable, which significantly impairs the service life. Here we present a reusable gallium (Ga)-based multi-layer electrochemical glucose biosensor to extend noninvasive monitoring of glucose in the interstitial fluid. This multilayer sensor includes Ga as a conductive interconnector, poly(3,4-ethylenedioxythiophene) as an electrode layer to prevent oxidation and metal leakage, a nano-Pt layer to enhance the electrochemical properties, and a nano-Prussian blue layer for reducing the hydrogen peroxide reduction potential. Most importantly, the biosensors can be renewed by automatically removing the modified nanocomposites via the electrolysis-induced bubbles and by electroplating without impairing the whole structure of the biosensor. The biosensor showed high sensitivity (24.6 μA mM-1 cm-2), wide linear range (0.01-26 mM), excellent stability (i.e., pH, long-term use) and superior selectivity, that is comparable to those of the current electrochemical tools for glucose detection. More importantly, incorporated with the reverse iontophoresis (RI), the Ga-based hybrid sensor was applied as a skin patch on mice for the in vivo noninvasive and continuous monitoring of ISF-borne glucose. The results showed a good correlation with that measured by blood glucometer. As a whole, this Ga-based electrochemical biosensor should endow new functions like biochemical analysis in biofluids for Ga-based soft bioelectronic sensing devices, in which almost are physical sensors. We believe that the reusability of electrochemically controllable processes may further inspire the development of more integrated and long-term stable gallium-based biosensing devices.

Efficient and Stable All-Inorganic Perovskite Solar Cells Prepared with ABX3-Like Precursors

Despite the fact that inorganic perovskites with supreme thermal stability are attractive photo-absorbers for emerging photovoltaic cells, intrinsic phase-instable issues pose challenges for obtaining satisfactory photovoltaic efficiencies and long-term device stability. Herein, we demonstrate an all-solution approach based on a series of perovskite-like products (PLP), namely NH4PbX3 (X = halogen) as the reactant for preparing inorganic perovskites featuring a heterojunction-resembling structure (HRS) and high material robustness. The creation of HRS is enabled by a self-migration and assembly process facilitated by the volatile characteristics of PLPs, as affirmed by joint experiential and theoretical investigations. We highlight that the particular structure of HRS is a key to the boost in material robustness, which translates to long-term device stability. Engaging compositional engineering on the PLPs allows us to regulate the energetics of surface components within the HRS, leading to gradient energy alignments to promote carrier transport and extraction in the device. Based on an optimized PLP (NH4PbCl2.8Br0.2) to form the HRS, the resultant solar cell yields a power conversion efficiency (PCE) exceeding 20%, showing excellent operational stability under illumination (the efficiency remains over 95% of its initial value after 1000hours of continuous illumination). The described PLP-based approach can be readily applied to a range of inorganic perovskite materials for receiving gains in photovoltaic performance.

Cerebral Microcirculation: Progress and Outlook of Laser Doppler Flowmetry in Neurosurgery and Neurointensive Care.

Laser Doppler flowmetry (LDF) is a well-established technique for the investigation of tissue microcirculation. Compared to skin, the use in the human brain is sparse. The measurement of cerebral microcirculation in neurointensive care and during neurosurgery is challenging and requires adaptation to the respective clinical setting. The aim of the review is to present state of the art and progress in neurosurgery and neurointensive care where LDF has proven useful and can find clinical importance in the investigation of cerebral microcirculation. The literature in the field is summarized and recent technical improvements regarding LDF systems and fiber optical probe designs for neurosurgical and neurocritical care described. By combining two signals from the LDF unit, the measurement of the microcirculation (Perfusion) and gray whiteness (TLI) of the brain tissue, the full potential of the device is achieved. For example, a forward-looking LDF-probe detects high-risk hemorrhage areas and gray-white matter boundaries along intraoperative trajectories during stereotactic neurosurgery. Proof of principles are given for LDF as a guidance tool in deep brain stimulation implantation, brain tumor needle biopsies, and as long-term monitoring device in neurocritical care. With well-designed fiber optical probes, surgical fixation, and signal processing for movement reduction, LDF monitoring of the cerebral microcirculation is successful up to 10 days. The use of LDF can be combined with other physiological measurement techniques, for example, fluorescence spectroscopy for identification of glioblastoma during tumor surgery. Fiber optics can also be used during magnetic resonance imaging (MRI). Despite the many advantages, fiber optical LDF has not yet reached its full potential in clinical neuro-applications. Multicenter studies are required to further evaluate LDF in neurosurgery and neurointensive care. In conclusion, the present status of LDF in neurosurgery and neurointensive care has been reviewed. By combining Perfusion and TLI with tailored probe designs the full potential of LDF can be achived in measuring cerebral microcirculation. This includes guidance during DBS implantation and needle biopsies, and long-term monitoring in neurocritical care.

Sustainability inspired fabrication of next generation neurostimulation and cardiac rhythm management electrodes via reactive hierarchical surface restructuring

Over the last two decades, platinum group metals (PGMs) and their alloys have dominated as the materials of choice for electrodes in long-term implantable neurostimulation and cardiac rhythm management devices due to their superior conductivity, mechanical and chemical stability, biocompatibility, corrosion resistance, radiopacity, and electrochemical performance. Despite these benefits, PGM manufacturing processes are extremely costly, complex, and challenging with potential health hazards. Additionally, the volatility in PGM prices and their high supply risk, combined with their scarce concentration of approximately 0.01 ppm in the earth’s upper crust and limited mining geographical areas, underscores their classification as critical raw materials, thus, their effective recovery or substitution worldwide is of paramount importance. Since postmortem recovery from deceased patients and/or refining of PGMs that are used in the manufacturing of the electrodes and microelectrode arrays is extremely rare, challenging, and highly costly, therefore, substitution of PGM-based electrodes with other biocompatible materials that can yield electrochemical performance values equal or greater than PGMs is the only viable and sustainable solution to reduce and ultimately substitute the use of PGMs in long-term implantable neurostimulation and cardiac rhythm management devices. In this article, we demonstrate for the first time how the novel technique of “reactive hierarchical surface restructuring” can be utilized on titanium—that is widely used in many non-stimulation medical device and implant applications—to manufacture biocompatible, low-cost, sustainable, and high-performing neurostimulation and cardiac rhythm management electrodes. We have shown how the surface of titanium electrodes with extremely poor electrochemical performance undergoes compositional and topographical transformations that result in electrodes with outstanding electrochemical performance.

Long-term intravenous devices: a narrative review of their placement.

This review summarizes the latest findings and recommendations about the characteristics, indications and use of peripheral and central long-term venous access devices.The various complications inherent in these devices are becoming better known, and their contributing factors determined, which could make it possible to reduce their incidence. Some measures are integrated into recommendations for good practice, such as appropriate selection of devices, the preferential use of the thinnest catheters, and cyanoacrylate glue and dressings impregnated with chlorhexidine. Improving understanding of the phenomena leading to infectious and thrombotic complications, as well as better knowing the differences between intravenous devices and their respective indications, should lead to improvement of in-hospital and out-of-hospital care.

Enhancing photoluminescence of monolayer MoS2 on h-BN substrate through plasmonic resonance for high-power optoelectronic devices

Abstract Hexagonal boron nitride (h-BN) is an excellent substrate material due to its superb thermal conductivity, excellent thermal stability and smooth surface qualities. In this study, a silicon-based h-BN substrate was prepared using the magnetron sputtering technique. Subsequently, monolayer MoS2 obtained by the CVD method was transferred onto the h-BN substrate. Then, Au-core-Ag-shell nanoparticles with a diameter of 80 nm were prepared by a self-assembly method and uniformly dispersed and spin-coated on the MoS2 surface. Applying a laser with a wavelength of 532 nm can effectively excite the plasma resonance effect of the system. Under the intense thermal effect induced by the high laser power and plasma effect, the h-BN substrate ensures that MoS2 exhibits less red-shift and higher photoluminescence intensity compared with SiO2 substrate due to its excellent thermal conductivity. This means that h-BN substrates are particularly suitable for optoelectronic applications under high laser power environments, and can maintain excellent optoelectronic device performance while effectively curbing overheating to ensure long-term stable device operation.

Detection of atrial fibrillation using a nonlinear Lorenz Scattergram and deep learning in primary care

BackgroundAtrial fibrillation (AF) is highly correlated with heart failure, stroke and death. Screening increases AF detection and facilitates the early adoption of comprehensive intervention. Long-term wearable devices have become increasingly popular for AF screening in primary care. However, interpreting data obtained by long-term wearable ECG devices is a problem in primary care. To diagnose the disease quickly and accurately, we aimed to build AF episode detection model based on a nonlinear Lorenz scattergram (LS) and deep learning.MethodsThe MIT-BIH Normal Sinus Rhythm Database, MIT-BIH Arrhythmia Database and the Long-Term AF Database were extracted to construct the MIT-BIH Ambulatory Electrocardiograph (MIT-BIH AE) dataset. We converted the long-term ECG into a two-dimensional LSs. The LSs from MIT-BIH AE dataset was randomly divided into training and internal validation sets in a 9:1 ratio, which was used to develop and internally validated model. We built a MOBILE-SCREEN-AF (MS-AF) dataset from a single-lead wearable ECG device in primary care for external validation. Performance was quantified using a confusion matrix and standard classification metrics.ResultsDuring the evaluation of model performance based on the LS, the sensitivity, specificity and accuracy of the model in diagnosing AF were 0.992, 0.973, and 0.983 in the internal validation set respectively. In the external validation set, these metrics were 0.989, 0.956, and 0.967, respectively. Furthermore, when evaluating the model’s performance based on ECG records in the MS-AF dataset, the sensitivity, specificity and accuracy of model diagnosis paroxysmal AF were 1.000, 0.870 and 0.876 respectively, and 0.927, 1.000 and 0.973 for the persistent AF.ConclusionsThe model based on the nonlinear LS and deep learning has high accuracy, making it promising for AF screening in primary care. It has potential for generalization and practical application.

Emerging Medical Technologies and Their Use in Bionic Repair and Human Augmentation.

As both the proportion of older people and the length of life increases globally, a rise in age-related degenerative diseases, disability, and prolonged dependency is projected. However, more sophisticated biomedical materials, as well as an improved understanding of human disease, is forecast to revolutionize the diagnosis and treatment of conditions ranging from osteoarthritis to Alzheimer's disease as well as impact disease prevention. Another, albeit quieter, revolution is also taking place within society: human augmentation. In this context, humans seek to improve themselves, metamorphosing through self-discipline or more recently, through use of emerging medical technologies, with the goal of transcending aging and mortality. In this review, and in the pursuit of improved medical care following aging, disease, disability, or injury, we first highlight cutting-edge and emerging materials-based neuroprosthetic technologies designed to restore limb or organ function. We highlight the potential for these technologies to be utilized to augment human performance beyond the range of natural performance. We discuss and explore the growing social movement of human augmentation and the idea that it is possible and desirable to use emerging technologies to push the boundaries of what it means to be a healthy human into the realm of superhuman performance and intelligence. This potential future capability is contrasted with limitations in the right-to-repair legislation, which may create challenges for patients. Now is the time for continued discussion of the ethical strategies for research, implementation, and long-term device sustainability or repair.

Inhibiting Interfacial Nonradiative Recombination in Inverted Perovskite Solar Cells with a Multifunctional Molecule.

Interface-induced nonradiative recombination losses at the perovskite/electron transport layer (ETL) are an impediment to improving the efficiency and stability of inverted (p-i-n) perovskite solar cells (PSCs). Tridecafluorohexane-1-sulfonic acid potassium (TFHSP) is employed as a multifunctional dipole molecule to modify the perovskite surface. The solid coordination and hydrogen bonding efficiently passivate the surface defects, thereby reducing nonradiative recombination. The induced positive dipole layer between the perovskite and ETLs improves the energy band alignment, enhancing interface charge extraction. Additionally, the strong interaction between TFHSP and the perovskite stabilizes the perovskite surface, while the hydrophobic fluorinated moieties prevent the ingress of water and oxygen, enhancing the device stability. The resultant devices achievea power conversion efficiency (PCE) of 24.6%. The unencapsulated devices retain91% of their initial efficiency after 1000 h in air with 60% relative humidity, and 95% after 500 h under maximum power point (MPP) tracking at 35°C. The utilization of multifunctional dipole molecules opens new avenues for high-performance and long-term stable perovskite devices.

Oxygen Vacancy Mediation in SnO2 Electron Transport Layers Enables Efficient, Stable, and Scalable Perovskite Solar Cells.

Previous findings have suggested a close association between oxygen vacancies in SnO2 and charge carrier recombination as well as perovskite decomposition at the perovskite/SnO2 interface. Underlying the fundamental mechanism holds great significance in achieving a more favorable balance between the efficiency and stability. In this study, we prepared three SnO2 samples with different oxygen vacancy concentrations and observed that a low oxygen vacancy concentration is conducive to long-term device stability. Iodide ions were observed to easily diffuse into regions with high oxygen vacancies, thereby speeding up the deprotonation of FAI, as made evident by the detection of the decomposition product formamide. In contrast, a high oxygen vacancy concentration in SnO2 could prevent hole injection, leading to a decrease in interfacial recombination losses. To suppress this decomposition reaction and address the trade-off, we designed a bilayer SnO2 structure to ensure highly efficient carrier transport still while maintaining a chemically inert surface. As a result, an enhanced efficiency of 25.06% (certified at 24.55% with an active area of 0.09 cm2 under fast scan) was achieved, and the extended operational stability maintained 90% of their original efficiency (24.52%) after continuous operation for nearly 2000 h. Additionally, perovskite submodules with an active area of 14 cm2 were successfully assembled with a PCE of up to 22.96% (20.09% with an aperture area).

Long-term cardiac computed tomography follow-up after left atrial appendage occlusion.

Left atrial appendage occlusion (LAAO) is performed increasingly, but long-term follow-up imaging data are lacking. The aim of this study was to evaluate the safety and durability of the Amplatzer Amulet device >4 years after LAAO. This was a prospective observational cohort study including 52 patients implanted with the Amplatzer Amulet device at Aarhus University Hospital, Denmark. A >4-year follow-up cardiac computed tomography (CT) scan after LAAO was performed and compared with the results from the 2-month and 12-month scans. The primary outcome was left atrial appendage (LAA) sealing based on distal LAA contrast patency and peridevice leakage (PDL), stratified into complete occlusion (grade 0 [G0]) and grade 1-3 leakage (G1-3), respectively. Secondary outcomes were low- and high-grade hypoattenuated thickening (HAT), device-related thrombosis (DRT) and device durability. The median (interquartile range [IQR]) follow-up time from LAAO to the latest CT scan was 5.8 years (4.5; 6.3). At 2-month (n=52), 12-month (n=27) and >4-year CT follow-ups (n=52), rates of both complete occlusion (33%, 37%, 35%) and G2 leaks (52%, 52%, 48%) remained stable. Rates of G1 leaks varied (14%, 4%, 6%) and G3 leaks rose (2%, 7%, 12%) from earliest to latest follow-up. The median left atrial (LA) volume increased from 127 mL (96; 176) to 144 mL (108; 182) and 147 mL (107; 193). No DRT was found. The structural device integrity was preserved. This study indicates a stable LAA sealing status throughout the follow-up period, emphasising the importance of the procedural result in avoiding PDL. Few patients displayed PDL progression, which might partly be related to LA remodelling with increasing volume. The long-term device durability appears excellent. Larger studies are warranted to confirm these findings.

Patient Outcomes in a Novel Osseointegrated Device for Transfemoral Amputation: a case series

Background Socket suspension (SS) prosthetics are the current standard for transfemoral amputee prosthetic management. The SS systems have been shown to be inefficient in energy transfer, leading to gait alteration, wear discomfort, and skin complications. Many studies have shown osseointegrated (OI) devices are not associated with these problems and offer many benefits. Purpose Through this report the authors will describe surgical outcomes following transfemoral amputation (TFA) surgery using a novel OI device. Methods Patients with problematic TFA were identified from 2013 to 2018 were treated with a novel OI system. Candidate TFA patients identified through record review as part of an IRB authorized retrospective study. The study group all had the following characteristics: (1)No diabetes, (2)no peripheral vascular disease, and (3)mature healed TFA. All study subjects had attempted use of SS and had failed for many reasons related to the skin to socket interface. The outcomes measured recorded included: (1)Q-TFA Scores, (2)SF-36 Score, (3)time coupled per day, (4)resolution of back pain, (5)residual limb pain, and (6)overall satisfaction. Radiographs of implanted stems were reviewed for evidence of loosening or bone on growth. Results A group of TFA patients (11) had been treated with the OI system and agreed for follow up evaluation. Mean age 52 (37-73) years at the time of OI stage I surgery, with a mean time of 9 (3-20) years post amputation to implantation of the OI system. Original indications for the amputation included: 1 chronic osteomyelitis, 1 neoplasm, and 9 traumatic. Mean time to from TFA to OI was 73 months (2- 216). All patients reported a reduction or complete resolution of back pain after OI. Ambulatory/device coupling status reported was mean 12 hours/day. Average Q-TFA Prosthetic use score 66.1, Prosthetic mobility score, 60.2, Problem score 18.2, and Global score 72. Average SF-36 PCS 56.2 and average MCS 70.0. Radiographs reviewed all showed 4 to 6mm of distal circumferential bone reabsorption with robust bone on growth in the diaphysis of the implanted femurs. Conclusion Early data on the effectiveness and safety of the custom Patriot™ OI device is favorable. Future study evaluating long-term device survivorship and patient reported outcomes is warranted. Bone remodeling post implantation and coupling showed positive effects of the system. This study found the custom OI device to be safe and effective in the management of TFA in patients with controlled indications.

Efficient electron injection layer for thermal stability of top emission phosphorescent organic light emitting diodes

Thermal stability holds significant importance in both high-resolution and large-area organic light-emitting diodes (OLEDs) due to its potential impacts on pixel shrinkage, thereby adversely affecting visual quality and long-term device functionality. The thermal instability could be from the thermal diffusion of metal ions or small molecules occurring at the interface between the electron injection layer (EIL) and the cathode material, influenced by differing surface properties and binding strength. In this study, we meticulously engineered magnesium fluoride (MgF2) as EIL to mitigate the aforementioned challenges. Important physical properties associated with the EIL/cathode interaction were systematically analyzed. Employing Ag:Yb (2.5:1) as the cathode, we achieved notable enhancements in current efficiency and a reduced turn-on voltage for a green device operating under optical microcavity conditions. Thermal degradation test conducted over 240 h on fabricated devices revealed that employing MgF2 as the EIL markedly enhanced thermal stability compared to devices utilizing Yb as the EIL reference. The robust EIL/cathode system observed herein is attributed to the high binding energy between the EIL and cathode materials utilized in this study.

An optoelectronic implantable neurostimulation platform allowing full MRI safety and optical sensing and communication

A novel programmable implantable neurostimulation platform based on photonic power transfer has been developed for various clinical applications with the main focus of being safe to use with MRI scanners. The wires usually conveying electrical current from the neurostimulator to the electrodes are replaced by optical fibers. Photovoltaic cells at the tip of the fibers convert laser light to biphasic electrical impulses together with feedback signals with 54% efficiency. Furthermore, a biocompatible, implantable and ultra-flexible optical lead was developed including custom optical fibers. The neurostimulator platform incorporates advanced signal processing and optical physiological sensing capabilities thanks to a hermetically sealed transparent nonmetallic casing. Skin transparency also allowed the development of a high-speed optical transcutaneous communication channel. This implantable neurostimulation platform was first adapted to a vagus nerve stimulator for the treatment of epilepsy. This neurostimulator has been designed to fulfill the requirements of a class III long-term implantable medical device. It has been proven compliant with standard ISO/TS10974 for 1.5 T and 3 T MRI scanners. The device poses no related threat and patients can safely undergo MRI without specific or additional precautions. Especially, the RF induced heating near the implant remains below 2 °C whatever the MRI settings used. The main features of this unique advanced neurostimulator and its architecture are presented. Its functional performance is evaluated, and results are described with a focus on optoelectronics aspects and MRI safety.

Surface aspects of novel Bio-HEAs MAO-treated in a Ca-, P-, and Mg-rich electrolyte

This study evaluated the effect of alloying elements, applied voltage, and bioactive species (Ca, P, and Mg) enrichment during the micro-arc oxidation (MAO) treatment of novel high entropy alloys (HEAs) targeted for biomedical applications. The non-equiatomic TiZrNbTaMo (TaMo), TiZrNbTaMn (TaMn), and TiZrNbFeMo (FeMo) samples were submitted to MAO treatment at distinct voltages (100, 200, and 300 V), then their chemical, phase, and morphological aspects were evaluated by x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), and scanning and transmission electron microscopy (SEM and TEM). Finally, the preliminary physicochemical behavior regarding contact angle and surface energy in distilled water at room temperature was evaluated. The results indicated that the alloying elements played a global role in the bulk’s phase composition, possessing distinct proportions of BCC and HCP phases. The MAO-treated surfaces depicted different mechanisms of anodic oxide growth and dielectric breakdown, forming the typical porous surface at distinct applied voltages. The bioactive species (Ca, P, and Mg) were gradually enriched in the oxide layer, composed of distinct nano-crystalline and amorphous layers that are typical of MAO-treated surfaces. As a result, roughness, contact angle and surface energy values of the MAO-treated samples were affected by the applied voltage and the bulk’s chemical composition, indicating potential for use in the biomedical field, especially as long-term implants and bone fixation devices.

Examining the impact of median arcuate ligament-induced celiac artery compression on target vessel patency, long-term survival and device integrity in fenestrated and branched endovascular repairs

ObjectiveTo evaluate the impact of celiac artery (CA) compression by median arcuate ligament (MAL) on technical metrics and long-term CA patency in patients with complex aortic aneurysms undergoing fenestrated/branched endograft repairs (F/B-EVARs). MethodsSingle-center, retrospective review of patients undergoing fenestrated/branched endovascular aortic aneurysm repairs and requiring incorporation of the CA between 2013 and 2023. Patients were divided into two groups—those with (MAL+) and without (MAL−) CA compression—based on preoperative computed tomography angiography findings. MAL was classified in three grades (A, B, and C) based on the degree and length of stenosis. Patients with MAL grade A had ≤50% CA stenosis measuring ≤3 mm in length. Those with grade B had 50% to 80% CA stenosis measuring 3 to 8 mm long, whereas those with grade C had >80% stenosis measuring >8 mm in length. End points included device integrity, CA patency and technical success—defined as successful implantation of the fenestrated/branched device with perfusion of CA and no endoleak. ResultsOne hundred and eighty patients with complex aortic aneurysms (pararenal, 128; thoracoabdominal, 52) required incorporation of the CA during fenestrated/branched endovascular aortic aneurysm repair. Majority (73%) were male, with a median age of 76 years (interquartile range [IQR], 69-81 years) and aneurysm size of 62 mm (IQR, 57-69 mm). Seventy-eight patients (43%) had MAL+ anatomy, including 33 patients with MAL grade A, 32 with grade B, and 13 with grade C compression. The median length of CA stenosis was 7.0 mm (IQR, 5.0-10.0 mm). CA was incorporated using fenestrations in 177 (98%) patients. Increased complexity led to failure in CA bridging stent placement in four MAL+ patients, but completion angiography showed CA perfusion and no endoleak, accounting for a technical success of 100%. MAL+ patients were more likely to require bare metal stenting in addition to covered stents (P = .004). Estimated blood loss, median operating room time, contrast volume, fluoroscopy dose and time were higher (P < .001) in MAL+ group. Thirty-day mortality was 3.3%, higher (5.1%) in MAL+ patients compared with MAL− patients (2.0 %). At a median follow-up of 770 days (IQR, 198-1525 days), endograft integrity was observed in all patients and CA events—kinking (n = 7), thrombosis (n = 1) and endoleak (n = 2) —occurred in 10 patients (5.6%). However, only two patients required reinterventions. MAL+ patients had overall lower long-term survival. ConclusionsCA compression by MAL is a predictor of increased procedural complexity during fenestrated/branched device implantation. However, technical success, long-term device integrity and CA patency are similar to that of patients with MAL− anatomy.