Surgical management of lower limb radiculopathy following acute singe-level osteoporotic vertebral fracture of lower lumbar spine in geriatric patient: a retrospective study.

BACKGROUND: Radiculopathy of the lower limb after acute osteoporotic vertebral fractures (OVFs) in the lower lumbar spine is uncommon in geriatric patients. Moreover, surgical intervention is generally recommended in patients who are irresponsive to conservative treatment. Determining an optimum surgical strategy is challenging considering the poor general condition of this population. Thus, herein, we established an algorithm for surgically managing this clinical scenario, hoping to provide a reference for making a surgical decision. METHODS: We retrospectively studied patients who suffered from new-onset radiculopathy of the lower limb after acute single-level OVFs in the lower lumbar spine and eventually underwent surgical intervention at our department. Information on the demographics, bone quality, AO spine classification of the vertebral fracture, pre-existing degenerative changes, including foraminal stenosis and lumbar disc herniation, and surgical intervention type was collected. Additionally, clinical outcomes, including preoperative and postoperative visual analog scale (VAS) scores for back and leg pain, Oswestry disability index (ODI), and MacNab criterion for response to surgery, were evaluated. RESULTS: From September 2019 to December 2021, a total of 22 patients with a mean age of 68.59 ± 9.74 years were analyzed. The most involved vertebra was L5 (54.5%), followed by L4 (27.3%) and L3 (18.2%). Among the 22 patients, 15 (68.2%) were diagnosed with the A1 type fracture of AO classification, and among them, 11 (73.3%) were characterized by the collapse of the inferior end plate (IEP). Three patients (13.6%) suffered from A2-type fractures, whereas four patients (18.2%) suffered from A3-type fractures. Pre-existing degenerative changes were observed in 12 patients (54.5%) of the patients. A total of 16 patients (72.7%) were treated by percutaneous kyphoplasty (PKP). Additionally, three patients underwent posterior instrumentation and fusion, two patients underwent a secondary endoscopic foraminoplasty, and one patient underwent a secondary radiofrequency ablation. The mean follow-up period was 17.42 ± 9.62 months. The mean VAS scores for leg and back pain and ODI decreased significantly after the surgery (P < 0.05). The total satisfaction rate at the last follow-up was 90.9% per the Macnab criterion. CONCLUSION: Patients with OVFs in the IEP are predisposed to suffer from radiculopathy of the lower limb. PKP alone or in combination with other minimally invasive surgical strategies is safe and effective in treating stable fractures. Additionally, aggressive surgical intervention should be considered in patients with unstable fractures or severe foraminal encroachment.

Enabling fast ionic transport in CeO2-La1-2xBaxBixFeO3 nanocomposite electrolyte for low temperature solid oxide fuel cell application.

Recent studies indicate that electrolyte ionic conductivity plays a pivotal role in reducing the operating temperature of solid oxide fuel cells (SOFCs). In this regard, nanocomposite electrolytes have drawn significant attention owing to their enhanced ionic conductivity and fast ionic transport. In this study, we fabricated CeO2-La1-2xBaxBixFeO3 nanocomposites and tested them as a high-performance electrolyte for low-temperature solid oxide fuel cells (LT-SOFCs). The prepared samples were characterized by their phase structure, surface, and interface property via transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), followed by being applied in SOFCs to examine their electrochemical performance. In the fuel cells, it was found that the optimal composition 90CeO2-10La1-2xBaxBixFeO3 electrolyte-based SOFC delivered a peak power density of 834 mW cm-2 along with an open circuit voltage (OCV) of 1.04 V at 550 °C. A comparative study revealed that the nanocomposite electrolyte exhibited a total conductivity of 0.11 S cm-1 at 550 °C. Moreover, the rectification curve manifested the formation of the Schottky junction, suppressing the electronic conduction. This study conclusively shows that the addition of La1-2xBaxBixFeO3 (LBBF) into ceria electrolyte is a viable approach for constructing high-performance electrolytes for LT-SOFCs.

Interfacial Disordering and Heterojunction Enabling Fast Proton Conduction.

The interfacial disorder is a general method to change the metal-oxygen compatibility and carrier density of heterostructure materials for ionic transport modulation. Herein, to enable high proton conduction, a semiconductor heterostructure based on spinel ZnFe2 O4 (ZFO) and fluorite CeO2 is developed and investigated in terms of structural characterization, first principle calculation, and electrochemical performance. Particular attention is paid to the interfacial disordering and heterojunction effects of the material. Results show that the heterostructure induces a disordered oxygen region at the hetero-interface of ZFO-CeO2 by dislocating oxygen atoms, leading to fast proton transport. As a result, the ZFO-CeO2 exhibits a high proton conductivity of 0.21 S cm-1 and promising fuel cell power output of 1070 mW cm-2 at 510 °C. Based upon these findings, a new mechanism is proposed by focusing on the change of O-O bond length to interpret the diffusion and acceleration of protons in ZFO-CeO2 on the basis of the Grotthuss mechanism. This study provides a new strategy to customize semiconductor heterostructure to enable fast proton conduction.

A practical method for the retrieval of tulip-head polyaxial pedicle screw by reusing the rod in revision and implants removal surgery: introduction of technique and evaluation of clinical outcomes.

BACKGROUND: The removal of spinal implants is needed in revision surgery or in some cases whose fracture had healed or fusion had occurred. The slip of polyaxial screw or mismatch of instruments would make this simple procedure intractable. Here we introduce a simple and practical method to address this clinical dilemma. METHODS: This is a retrospective study. The patients underwent new technique for retrieving the implants from July 2019 to July 2022 were labeled as group A, while the patients underwent traditional implants retrieval technique from January 2017 to January 2020 were labeled as group B. Patients in each group were subdivided into revision surgery group (r group) and simple implants removal group (s group) according to the surgery fashion. For the new technique, the retrieved rod was cut off to a proper length which was matched with the size of tulip head, and was replaced into the tulip head. After tightened with nut, a monoaxial screw-rod "construct" was formed. Then the "construct" can be retrieved by a counter torque. The operation duration, intraoperative blood loss, post-operative bacteria culture, hospital stay and costs were analyzed. RESULTS: A total of 116 polyaxial screws with difficult retrieval (43 screws in group A, 73 screws in group B) in 78 patients were recorded, in which 115 screws were successfully retrieved. Significant differences were found in the mean operation duration, intraoperative blood loss when comparing the r group in group A and B, as well as the s group in group A and B (P < 0.05). There were no significant differences in hospital stay and costs between group A and B. Three patients were found positive bacteria culture of drainage tube/tape in group A (3/30), while 7 patients in group B (7/48). The most prevalent bacteria was Propionibacterium acnes. CONCLUSION: This technique is practical and safe in retrieving tulip head poly-axial screw. Reduced operation duration and intraoperative bloods loss may potentially alleviate the hospitalization burden of patients. Positive bacterial cultivation results are common after implants removal surgery, but they rarely represent an organized infection. A positive culture with P. acnes or S. epidermidis should be interpreted with caution.

Modified unilateral iliac screw fixation with partial reduction in the treatment of high-grade spondylolisthesis at L5/S1 in adult patients: introduction of key technique, report of clinical outcomes and analysis of spinopelvic parameters.

BACKGROUND: Management of high-grade spondylolisthesis (HGS) remains challenging. Spinopelvic fixation such as iliac screw (IS) was developed to deal with HGS. However concerns regarding constructs prominence and increased infection-related revision surgery have complicated it's use. We aim to introduce the modified iliac screw (IS) technique in treating high-grade L5/S1 spondylolisthesis and it's clinical and radiological outcomes. METHODS: Patients with L5/S1 HGS who underwent modified IS fixation were enrolled. Pre- and postsurgical upright full spine radiographs were obtained to analyze sagittal imbalance, spinopelvic parameters, pelvic incidence-lumbar lordosis mismatch (PI-LL), slip percentage, slip angle (SA), and lumbosacral angle (LSA). Visual analogue scale (VAS), Oswestry disability index (ODI) were evaluated pre- and postoperatively for clinical outcomes assessment. Estimated blood loss, operating time, perioperative complications and revision surgery were documented. RESULTS: From Jan 2018 to March 2020, 32 patients (15 males) with mean age of 58.66 ± 7.77 years were included. The mean follow-up period was 49 months. The mean operation duration was 171.67 ± 36.66 min. At the last follow-up: (1) the VAS and ODI score were significantly improved (p < 0.05), (2) PI increased by an average of 4.3°, the slip percent, SA and LSA were significantly improved (p < 0.05), (3) four patients (16.7%) with global sagittal imbalance recovered a good sagittal alignment, PI-LL within ± 10° was observed in all patients. One patient experienced wound infection. One patient underwent a revision surgery due to pseudoarthrosis at L5/S1. CONCLUSION: The modified IS technique is safe and effective in treating L5/S1 HGS. Sparing use of offset connector could reduce hardware prominence, leading to lower wound infection rate and less revision surgery. The long-term clinical affection of increased PI value is unknown.

Improved Ionic Transport Using a Novel Semiconductor Co0.6Mn0.4Fe0.4Al1.6O4 and Its Heterostructure with Zinc Oxide for Electrolyte Membrane in LT-CFCs.

Improving the ionic conductivity and slow oxygen reduction electro-catalytic activity of reactions occurring at low operating temperature would do wonders for the widespread use of low-operating temperature ceramic fuel cells (LT-CFCs; 450-550 °C). In this work, we present a novel semiconductor heterostructure composite made of a spinel-like structure of Co0.6Mn0.4Fe0.4Al1.6O4 (CMFA) and ZnO, which functions as an effective electrolyte membrane for solid oxide fuel cells. For enhanced fuel cell performance at sub-optimal temperatures, the CMFA-ZnO heterostructure composite was developed. We have shown that a button-sized SOFC fueled by H2 and ambient air can provide 835 mW/cm2 of power and 2216 mA/cm2 of current at 550 °C, possibly functioning down to 450 °C. In addition, the oxygen vacancy formation energy and activation energy of the CMFA-ZnO heterostructure composite is lower than those of the individual CMFA and ZnO, facilitating ion transit. The improved ionic conduction of the CMFA-ZnO heterostructure composite was investigated using several transmission and spectroscopic measures, including X-ray diffraction, photoelectron, and UV-visible spectroscopy, and density functional theory (DFT) calculations. These findings suggest that the heterostructure approach is practical for LT-SOFCs.

High-performing and stable semiconductor yttrium-doped gadolinium electrolyte for low-temperature solid oxide fuel cells.

High-performing electrolytes at low operating temperatures have become an inevitable trend in the development of low-temperature solid oxide fuel cells (LT-SOFCs). Such electrolytes have drawn significant attention due to their appeal for high performance. Herein, we propose a new material by doping Y3+ into Gd2O3 for LT-SOFC electrolyte use. The prepared material was characterized in terms of crystal structure, surface, and interface properties, followed by its application in LT-SOFCs. YDG delivered promising SOFC performance with a power density of 1046 mW cm-2 at 550 °C along with high ionic conductivity of 0.19 S cm-1. Moreover, impedance spectra revealed that YDG exhibited the least ohmic resistance of 0.06-0.09 Ω cm2 at 550-460 °C. Furthermore, stable operation for 60 h demonstrated the chemical stability of the material in reduced temperature environments. Density function theory was also applied to analyze the electronic band structure and density of states of the synthesized sample. Our findings thus certify that YDG as a high-performing electrolyte at low operating temperatures.

Strontium-Cobaltite-Based Perovskite (SrCoO3) for Solar-Driven Interfacial Evaporation Systems for Clean Water Generation.

Solar-driven evaporation technology is often used in areas with limited access to clean water, as it provides a low-cost and sustainable method of water purification. Avoiding salt accumulation is still a substantial challenge for continuous desalination. Here, an efficient solar-driven water harvester that consists of strontium-cobaltite-based perovskite (SrCoO3) anchored on nickel foam (SrCoO3@NF) is reported. Synced waterways and thermal insulation are provided by a superhydrophilic polyurethane substrate combined with a photothermal layer. The structural photothermal properties of SrCoO3 perovskite have been extensively investigated through state-of-the-art experimental investigations. Multiple incident rays are induced inside the diffuse surface, permitting wideband solar absorption (91%) and heat localization (42.01 °C @ 1 sun). Under 1 kW m-2 solar intensity, the integrated SrCoO3@NF solar evaporator has an outstanding evaporation rate (1.45 kg/m2 h) and solar-to-vapor conversion efficiency (86.45% excluding heat losses). In addition, long-term evaporation measurements demonstrate small variance under sea water, illustrating the system's working capacity for salt rejection (1.3 g NaCl/210 min), which is excellent for an efficient solar-driven evaporation application compared to other carbon-based solar evaporators. According to the findings of this research, this system offers significant potential for producing fresh water devoid of salt accumulation for use in industrial applications.

Nanocomposite-Enhanced Efficient Evaporation System for Solar-Driven Seawater Desalination-An Optimized Design for Clean Water Production.

Solar-driven evaporation is a promising technology for desalinating seawater and wastewater without mechanical or electrical energy. The approaches to obtaining fresh water with higher evaporation efficiency are essential to address the water-scarcity issue in remote sensing areas. Herein, we report a highly efficient solar evaporator derived from the nanocomposite of anatase TiO2/activated carbon (TiO2/AC), which was coated on washable cotton fabric using the dip-dry technique for solar water evaporation. The ultra-black fabric offers enhanced solar absorption (93.03%), hydrophilic water transport, and an efficient evaporation rate of 1.65 kg/m2h under 1 kW m-2 or one sun solar intensity. More importantly, the sideways water channels and centralized thermal insulation of the designed TiO2/AC solar evaporator accumulated photothermal heat at the liquid and air interface along with an enhanced surface temperature of 40.98 °C under one sun. The fabricated solar evaporator desalinated seawater (3.5 wt%) without affecting the evaporation rates, and the collected condensed water met the standard of drinking water set by the World Health Organization (WHO). This approach eventually enabled the engineering design groups to develop the technology pathways as well as optimum conditions for low-cost, scalable, efficient, and sustainable solar-driven steam generators to cope with global water scarcity.

A-site deficient semiconductor electrolyte Sr1-x Co x FeO3-δ for low-temperature (450-550 °C) solid oxide fuel cells.

Fast ionic conduction at low operating temperatures is a key factor for the high electrochemical performance of solid oxide fuel cells (SOFCs). Here an A-site deficient semiconductor electrolyte Sr1-x Co x FeO3-δ is proposed for low-temperature solid oxide fuel cells (LT-SOFCs). A fuel cell with a structure of Ni/NCAL-Sr0.7Co0.3FeO3-δ -NCAL/Ni reached a promising performance of 771 mW cm-2 at 550 °C. Moreover, appropriate doping of cobalt at the A-site resulted in enhanced charge carrier transportation yielding an ionic conductivity of >0.1 S cm-1 at 550 °C. A high OCV of 1.05 V confirmed that neither short-circuiting nor power loss occurred during the operation of the prepared SOFC device. A modified composition of Sr0.5Co0.5FeO3-δ and Sr0.3Co0.7FeO3-δ also reached good fuel cell performance of 542 and 345 mW cm-2, respectively. The energy bandgap analysis confirmed optimal cobalt doping into the A-site of the prepared perovskite structure improved the charge transportation effect. Moreover, XPS spectra showed how the Co-doping into the A-site enhanced O-vacancies, which improve the transport of oxide ions. The present work shows that Sr0.7Co0.3FeO3-δ is a promising electrolyte for LT-SOFCs. Its performance can be boosted with Co-doping to tune the energy band structure.

Interfacial Photothermal Heat Accumulation for Simultaneous Salt Rejection and Freshwater Generation; an Efficient Solar Energy Harvester.

Water scarcity has emerged as an intense global threat to humanity and needs prompt attention from the scientific community. Solar-driven interfacial evaporation and seawater desalination are promising strategies to resolve the primitive water shortage issue using renewable resources. However, the fragile solar thermal devices, complex fabricating techniques, and high cost greatly hinder extensive solar energy utilization in remote locations. Herein, we report the facile fabrication of a cost-effective solar-driven interfacial evaporator and seawater desalination system composed of carbon cloth (CC)-wrapped polyurethane foam (CC@PU). The developed solar evaporator had outstanding photo-thermal conversion efficiency (90%) with a high evaporation rate (1.71 kg m-2 h-1). The interfacial layer of black CC induced multiple incident rays on the surface allowing the excellent solar absorption (92%) and intensifying heat localization (67.37 °C) under 1 kW m-2 with spatially defined hydrophilicity to facilitate the easy vapor escape and validate the efficacious evaporation structure using extensive solar energy exploitation for practical application. More importantly, the long-term evaporation experiments with minimum discrepancy under seawater conditions endowed excellent mass change (15.24 kg m-2 in consecutive 8 h under 1 kW m-2 solar irradiations) and promoted its operational sustainability for multi-media rejection and self-dissolving potential (3.5 g NaCl rejected from CC@PU surface in 210 min). Hence, the low-cost and facile fabrication of CC@PU-based interfacial evaporation structure showcases the potential for enhanced solar-driven interfacial heat accumulation for freshwater production with simultaneous salt rejection.

Tunable magneto-optical and interfacial defects of Nd and Cr-doped bismuth ferrite nanoparticles for microwave absorber applications.

Tunable microwave absorption characteristics are highly desirable for industrial applications such as antenna, absorber, and biomedical diagnostics. Here, we report BiNdxCrxFe1-2xO3 (x = 0, 0.05, 0.10, 0.15) nanoparticles (NPs) with electromagnetic matching, which exhibit tunable magneto-optical and feasible microwave absorption characteristics for microwave absorber applications. The experimental results and theoretical calculations demonstrate the original bismuth ferrite (BFO) crystal structure, while Nd and Cr injection in the BFO structure may cause to minimize dielectric losses and enhance magnetization by producing interfacial defects in the spinel structure. Nd and Cr co-doping plays a key role in ordering the BFO crystal structure, resulting in improved microwave absorption characteristics. The BiNd0.10Cr0.10Fe1.8O3 (BNCF2) sample exhibits a remarkable reflection loss (RL) of -37.7 dB with a 3-mm thickness in the 10.15 GHz-10.30 GHz frequency region. Therefore, Nd and Cr doping in BFO nanoparticles opens a new pathway to construct highly efficient BFO-based materials for tunable frequency, stealth, and microwave absorber applications.

Recent Progress in Semiconductor-Ionic Conductor Nanomaterial as a Membrane for Low-Temperature Solid Oxide Fuel Cells.

Reducing the operating temperature of Solid Oxide Fuel Cells (SOFCs) to 300-600 °C is a great challenge for the development of SOFC. Among the extensive research and development (R&D) efforts that have been done on lowering the operating temperature of SOFCs, nanomaterials have played a critical role in improving ion transportation in electrolytes and facilitating electrochemical catalyzation of the electrodes. This work reviews recent progress in lowering the temperature of SOFCs by using semiconductor-ionic conductor nanomaterial, which is typically a composition of semiconductor and ionic conductor, as a membrane. The historical development, as well as the working mechanism of semiconductor-ionic membrane fuel cell (SIMFC), is discussed. Besides, the development in the application of nanostructured pure ionic conductors, semiconductors, and nanocomposites of semiconductors and ionic conductors as the membrane is highlighted. The method of using nano-structured semiconductor-ionic conductors as a membrane has been proved to successfully exhibit a significant enhancement in the ionic conductivity and power density of SOFCs at low temperatures and provides a new way to develop low-temperature SOFCs.

Self-Assembled Triple (H+/O2-/e-) Conducting Nanocomposite of Ba-Co-Ce-Y-O into an Electrolyte for Semiconductor Ionic Fuel Cells.

Triple (H+/O2-/e-) conducting oxides (TCOs) have been extensively investigated as the most promising cathode materials for solid oxide fuel cells (SOFCs) because of their excellent catalytic activity for oxygen reduction reaction (ORR) and fast proton transport. However, here we report a stable twin-perovskite nanocomposite Ba-Co-Ce-Y-O (BCCY) with triple conducting properties as a conducting accelerator in semiconductor ionic fuel cells (SIFCs) electrolytes. Self-assembled BCCY nanocomposite is prepared through a complexing sol-gel process. The composite consists of a cubic perovskite (Pm-3m) phase of BaCo0.9Ce0.01Y0.09O3-δ and a rhombohedral perovskite (R-3c) phase of BaCe0.78Y0.22O3-δ. A new semiconducting-ionic conducting composite electrolyte is prepared for SIFCs by the combination of BCCY and CeO2 (BCCY-CeO2). The fuel cell with the prepared electrolyte (400 µm in thickness) can deliver a remarkable peak power density of 1140 mW·cm-2 with a high open circuit voltage (OCV) of 1.15 V at 550 °C. The interface band energy alignment is employed to explain the suppression of electronic conduction in the electrolyte. The hybrid H+/O2- ions transport along the surfaces or grain boundaries is identified as a new way of ion conduction. The comprehensive analysis of the electrochemical properties indicates that BCCY can be applied in electrolyte, and has shown tremendous potential to improve ionic conductivity and electrochemical performance.

An Interface Heterostructure of NiO and CeO2 for Using Electrolytes of Low-Temperature Solid Oxide Fuel Cells.

Interface engineering can be used to tune the properties of heterostructure materials at an atomic level, yielding exceptional final physical properties. In this work, we synthesized a heterostructure of a p-type semiconductor (NiO) and an n-type semiconductor (CeO2) for solid oxide fuel cell electrolytes. The CeO2-NiO heterostructure exhibited high ionic conductivity of 0.2 S cm-1 at 530 °C, which was further improved to 0.29 S cm-1 by the introduction of Na+ ions. When it was applied in the fuel cell, an excellent power density of 571 mW cm-1 was obtained, indicating that the CeO2-NiO heterostructure can provide favorable electrolyte functionality. The prepared CeO2-NiO heterostructures possessed both proton and oxygen ionic conductivities, with oxygen ionic conductivity dominating the fuel cell reaction. Further investigations in terms of electrical conductivity and electrode polarization, a proton and oxygen ionic co-conducting mechanism, and a mechanism for blocking electron transport showed that the reconstruction of the energy band at the interfaces was responsible for the enhanced ionic conductivity and cell power output. This work presents a new methodology and scientific understanding of semiconductor-based heterostructures for advanced ceramic fuel cells.

Nanotechnology Based Green Energy Conversion Devices with Multifunctional Materials at Low Temperatures.

BACKGROUND: Nanocomposites (integrating the nano and composite technologies) for advanced fuel cells (NANOCOFC) demonstrate the great potential to reduce the operational temperature of solid oxide fuel cell (SOFC) significantly in the low temperature (LT) range 300-600ºC. NANOCOFC has offered the development of multi-functional materials composed of semiconductor and ionic materials to meet the requirements of low temperature solid oxide fuel cell (LTSOFC) and green energy conversion devices with their unique mechanisms. DESCRIPTION: This work reviews the recent developments relevant to the devices and the patents in LTSOFCs from nanotechnology perspectives that reports advances including fabrication methods, material compositions, characterization techniques and cell performances. CONCLUSION: Finally, the future scope of LTSOFC with nanotechnology and the practical applications are also discussed.