Efficacy of cementless porous tantalum tibial components versus cemented tibial components in primary total knee arthroplasty: A meta-analysis.

BACKGROUND: Total knee arthroplasty involves the use of cemented tibial components for fixation. In recent years, cementless porous tantalum tibial components have been increasingly utilized. The aim of this meta-analysis was to compare the efficacy of cementless porous tantalum tibial components with traditional cemented tibial components in terms of postoperative outcomes following total knee arthroplasty. METHODS: Relevant literature was retrieved from Cochrane Library, PubMed, Embase, and Web of Science using the search terms "(trabecular metal OR Porous tantalum)" AND "knee" up to July 2023. The weighted mean difference with a 95% confidence interval was used as the effect size measure to evaluate the functional recovery of the knee joint, radiological analysis, complications, and implant revisions between cementless porous tantalum tibial components and traditional cemented tibial components after total knee arthroplasty. Review Manager 5.3 was utilized to conduct a comparative analysis of all included studies. RESULTS: Nine studies with a total of 1117 patients were included in this meta-analysis, consisting of 447 patients in the porous tantalum group and 670 patients in the cemented group. Radiological analysis demonstrated that the porous tantalum group had better outcomes than the cemented group (P < .05). The combined results for the 5-year and 10-year follow-ups, range of motion, Western Ontario and McMaster University Osteoarthritis Index, complications, and implant revisions showed no significant differences between the porous tantalum and cemented groups. CONCLUSION: The results of the 5-year and 10-year follow-ups indicate that the use of cementless porous tantalum tibial components is comparable to traditional cemented tibial components, with no significant advantages observed. However, at the 5-year follow-up, the porous tantalum group demonstrated a good bone density in the proximal tibia. Future studies with a larger sample size, long-term clinical follow-up, and radiological results are needed to verify the differences between the 2 implants.

Selective Laser Melting of the Porous Ta Scaffold with Mg-Doped Calcium Phosphate Coating for Orthopedic Applications.

Addressing the repair of large-scale bone defects has become a hot research topic within the field of orthopedics. This study assessed the feasibility and effectiveness of using porous tantalum scaffolds to treat such defects. These scaffolds, manufactured using the selective laser melting (SLM) technology, possessed biomechanical properties compatible with natural bone tissue. To enhance the osteogenesis bioactivity of these porous Ta scaffolds, we applied calcium phosphate (CaP) and magnesium-doped calcium phosphate (Mg-CaP) coatings to the surface of SLM Ta scaffolds through a hydrothermal method. These degradable coatings released calcium and magnesium ions, demonstrating osteogenic bioactivity. Experimental results indicated that the Mg-CaP group exhibited biocompatibility comparable to that of the Ta group in vivo and in vitro. In terms of osteogenesis, both the CaP group and the Mg-CaP group showed improved outcomes compared to the control group, with the Mg-CaP group demonstrating superior performance. Therefore, both CaP and magnesium-CaP coatings can significantly enhance the osseointegration of three-dimensional-printed porous Ta, thereby increasing the surface bioactivity. Overall, the present study introduces an innovative approach for the biofunctionalization of SLM porous Ta, aiming to enhance its suitability as a bone implant material.

Customized design and biomechanical property analysis of 3D-printed tantalum intervertebral cages.

BACKGROUND: Intervertebral cages used in clinical applications were often general products with standard specifications, which were challenging to match with the cervical vertebra and prone to cause stress shielding and subsidence. OBJECTIVE: To design and fabricate customized tantalum (Ta) intervertebral fusion cages that meets the biomechanical requirements of the cervical segment. METHODS: The lattice intervertebral cages were customized designed and fabricated by the selective laser melting. The joint and muscle forces of the cervical segment under different movements were analyzed using reverse dynamics method. The stress characteristics of cage, plate, screws and vertebral endplate were analyzed by finite element analysis. The fluid flow behaviors and permeability of three lattice structures were simulated by computational fluid dynamics. Compression tests were executed to investigate the biomechanical properties of the cages. RESULTS: Compared with the solid cages, the lattice-filled structures significantly reduced the stress of cages and anterior fixation system. In comparison to the octahedroid and quaddiametral lattice-filled cages, the bitriangle lattice-filled cage had a lower stress shielding rate, higher permeability, and superior subsidence resistance ability. CONCLUSION: The inverse dynamics simulation combined with finite element analysis is an effective method to investigate the biomechanical properties of the cervical vertebra during movements.

Fabrication of a novel tantalum boride/vanadium carbide modified screen-printed carbon electrode for voltammetric determination of pimonidazole in bio-fluids.

For the first time, a tumour hypoxia marker detection has been developed using two-dimensional layered composite modified electrodes in biological and environmental samples. The concept of TaB2 and V4C3-based MXene composite materials is not reported hitherto using ball-milling and thermal methods and it remains the potentiality of the present work. The successful formation is confirmed through various characterisation techniques like X-ray crystallography, scanning electron microscopy photoelectron, and impedance spectroscopy. A reliable and repeatable electrochemical sensor based on TaB2@V4C3/SPCE was developed for quick and extremely sensitive detection of pimonidazole by various electroanalytical methods. It has been shown that the modified electrode intensifies the reduction peak current and causes a decrease in the potential for reduction, in comparison with the bare electrode. The proposed sensor for pimonidazole reduction has strong electrocatalytic activity and high sensitivity, as demonstrated by the cyclic voltammetry approach. Under the optimal experimental circumstances, differential pulse voltammetry techniques were utilised for generating the wide linear range (0.02 to 928.51 µM) with a detection limit of 0.0072 µM. The resultant data demonstrates that TaB2@V4C3/SPCE nano-sensor exhibits excellent stability, reliability, and repeatability in the determination of pimonidazole. Additionally, the suggested sensor was successfully used to determine the presence of pimonidazole in several real samples, such as human blood serum, urine, water, and drugs.

Metal-polyphenol networks-modified tantalum plate for craniomaxillofacial reconstruction.

Using three-dimensional (3D) printing technology to make the porous tantalum plate and modify its surface. The physicochemical properties, cytocompatibility, antioxidant capacity, and histocompatibility of the modified materials were evaluated to prepare for the repair of craniomaxillofacial bone defects. The porous tantalum plates were 3D printed by selective laser melting technology. Tantalum plates were surface modified with a metal polyphenol network. The surface-modified plates were analyzed for cytocompatibility using thiazolyl blue tetrazolium bromide and live/dead cell staining. The antioxidant capacity of the surface-modified plates was assessed by measuring the levels of intracellular reactive oxygen species, reduced glutathione, superoxide dismutase, and malondialdehyde. The histocompatibility of the plates was evaluated by animal experiments. The results obtained that the tantalum plates with uniform small pores exhibited a high mechanical strength. The surface-modified plates had much better hydrophilicity. In vitro cell experiments showed that the surface-modified plates had higher cytocompatibility and antioxidant capacity than blank tantalum plates. Through subcutaneous implantation in rabbits, the surface-modified plates demonstrated good histocompatibility. Hence, surface-modified tantalum plates had the potential to be used as an implant material for the treatment of craniomaxillofacial bone defects.

An investigation on protection properties of Tantalum (V) oxide reinforced glass screens on unexposed breast tissue for mammography examinations.

INTRODUCTION: The utilization of radiation shielding material positioned between the both breasts are crucial for the reduction of glandular dose and the safeguarding of the contralateral breast during mammographic procedures. This study proposes an alternative substance for shielding the contralateral breast from radiation exposure during mammography screening. METHODS: In this study, we present an analysis of the shielding effectiveness of transparent glass that has been doped with Tantalum (V) oxide encoded as BTZT6. The evaluation of this shielding material was conducted using the MCNPX code, specifically for the ipsilateral and contralateral breasts. The design of the left and right breast phantoms involved the creation of three-layer heterogeneous breast phantoms, consisting of varying proportions of glandular tissue (25%, 50%, and 75%). The design of BTZT6 and lead-acrylic shielding screens is implemented using the MCNPX code. The comparative analysis of dose outcomes is conducted to assess the protective efficacy of BTZT6 and lead-acrylic shielding screens. RESULTS: The utilization of BTZT6 shielding material resulted in a reduction in both breast dose and skin dose exposure when compared to the lead-acrylic shield. CONCLUSION: Based on the findings acquired, the utilization of BTZT6 shielding material screens during mammography procedures involving X-rays with energy levels ranging from 26 to 30 keV is associated with a decrease in radiation dose. IMPLICATIONS FOR PRACTICE: It can be inferred that the utilization of BTZT6 demonstrates potential efficacy in mitigating excessive radiation exposure to the breasts and facilitating the quantification of glandular doses in mammography procedures.

Morphology of Nanostructured Tantalum Oxide Controls Stem Cell Differentiation and Improves Corrosion Behavior.

Tantalum is receiving increasing attention in the biomedical field due to its biocompatible nature and superior mechanical properties. However, the bioinert nature of tantalum still poses a challenge and limits its integration into the bone tissue. To address these issues, we fabricated nanotubular (NT), nanocoral (NC), and nanodimple morphologies on tantalum surfaces via anodization. The size of these nanofeatures was engineered to be approximately 30 nm for all anodized samples. Thus, the influence of the anodized nanostructured morphology on the chemical and biological properties of tantalum was evaluated. The NT and NC samples exhibited higher surface roughness, surface energy, and hydrophilicity compared to the nonanodized samples. In addition, the NT samples exhibited the highest corrosion resistance among all of the investigated samples. Biological experiments indicated that NT and NC samples promoted human adipose tissue-derived mesenchymal stem cell (hADMSC) spreading and proliferation up to 5 days in vitro. ALP, COL1A1, and OSC gene expressions as well as calcium mineral synthesis were upregulated on the NT and NC samples in the second and third weeks in vitro. These findings highlight the significance of nanostructured feature morphology for anodized tantalum, where the NT morphology was shown to be a potential candidate for orthopedic applications.

Cationic tantalum oxide nanoparticle contrast agent for micro computed tomography reveals articular cartilage proteoglycan distribution and collagen architecture alterations.

OBJECTIVE: Cationic tantalum oxide nanoparticles (Ta2O5-cNPs), as a newly introduced contrast agent for computed tomography of cartilage, offer quantitative evaluation of proteoglycan (PG) content and biomechanical properties. However, knowledge on the depth-wise impact of cartilage constituents on nanoparticle diffusion, particularly the influence of the collagen network, is lacking. In this study, we aim to establish the depth-dependent relationship between Ta2O5-cNP diffusion and cartilage constituents (PG content, collagen content and network architecture). METHODS: Osteochondral samples (n = 30) were harvested from healthy equine stifle joints (N = 15) and the diffusion of 2.55 nm diameter cationic Ta2O5-cNPs into the cartilage was followed with micro computed tomography (µCT) imaging for up to 96 hours. The diffusion-related parameters, Ta2O5-cNP maximum partition (Pmax) and diffusion time constant, were compared against biomechanical and depth-wise structural properties. Biomechanics were assessed using stress-relaxation and sinusoidal loading protocols, whereas PG content, collagen content and collagen network architecture were determined using digital densitometry, Fourier-transform infrared spectroscopy and polarized light microscopy, respectively. RESULTS: The Pmax correlates with the depth-wise distribution of PGs (bulk Spearman's ρ = 0.87, p < 0.001). More open collagen network architecture at the superficial zone enhances intake of Ta2O5-cNPs, but collagen content overall decreases the intake. The Pmax values correlate with the equilibrium modulus (ρ = 0.80, p < 0.001) of articular cartilage. CONCLUSION: This study establishes the feasibility of Ta2O5-cNPs for the precise and comprehensive identification of biomechanical and structural changes in articular cartilage via contrast-enhanced µCT.

Designing step-scheme AgI decorated Ta2O5-x heterojunctions for boosted photodegradation of organic pollutants.

Step-scheme (S-scheme) AgI decorated Ta2O5-x heterojunctions have been designed and synthesized via a combination of solvothermal and chemical deposition methods for enhanced visible-light harvesting and high-performance photocatalysis. The AgI nanoparticles showed great influences on the visible-light absorption and charge separation between AgI and Ta2O5-x microspheres. The experimental results indicated that the as-prepare AgI/Ta2O5-x composites achieved enhanced photocatalytic performance towards tetracycline degradation under visible light, and the AgI/Ta2O5-x-11 sample displayed the highest photocatalytic performance and the maximum rate constant of approximately 0.09483 min-1, which was 7.22 times that of Ta2O5-x microspheres and 2.56 times that of AgI, respectively. The highly enhanced photocatalytic performance was mainly attributed to the construction of S-scheme heterostructure and formation of oxygen vacancies in Ta2O5-x microspheres. In addition, the trapping experimental and DMPO spin-trapping ESR spectra confirmed the ⸱O2- and ⸱OH species as the main radicals during tetracycline degradation. Current work indicates an S-scheme tantalum-based composites for high-performance environmental photocatalysis.

Transforaminal lumbar interbody fusion with a tantalum cage: lumbar lordosis redistribution and sacral slope restoration with a modified posterior technique.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF), a commonly used procedure in spine surgery, has the advantage of a lower incidence of nerve lesions compared to the posterior lumbar interbody fusion (PLIF) technique. The intersomatic arthrodesis has always been carried out with a single tantalum cage normally used for PLIF. Tantalum is a metal that is particularly used in orthopedic surgery. It has a modulus of elasticity similar to marrow and leads to high primary stability of the implant. MATERIALS AND METHODS: Our study was a retrospective monocentric observational study evaluating clinical and radiological outcomes of tantalum cages in a modified TLIF technique with posterior instrumentation and autologous and/or homologous posterolateral bone grafting. The aim of the study was to evaluate clinical outcomes and the increase in or redistribution of lumbar lordosis. The intersomatic arthrodesis was always carried out with a single tantalum cage normally used for PLIF to reduce the neurological risk. We retrospectively studied 105 patients who were treated with a modified unilateral TLIF approach by two surgeons between 2013 and 2018. We evaluated the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) for back pain, global lumbar lordosis, lordosis of L4-sacrum, segmental lordosis of functional motion units that underwent arthrodesis, pelvic tilt, pelvic incidence, and the sacral slope in 77 patients. All patients were suffering from grade III or IV Pfirrmann, instability, or foraminal post-laminectomy stenosis and/or grade I-II degenerative spondylolisthesis or low-grade isthmic spondylolisthesis. They had no significant sagittal imbalance, with a sagittal vertical axis (SVA) of < 5 mm. The average follow-up duration was 30 months. RESULTS: We achieved excellent clinical results, with only four cases of failure (5.2%). Moreover, we noticed a statistically significant redistribution of lumbar lordosis, with an average percentage increase in L4-S1 lordosis equal to 19.9% (P < 0.001), an average increase in the L4-S1/Lumbar lordosis (LL) ratio from 0.53 to 0.63 (P < 0.001), and a mean percentage increase in sacral slope equal to 7.6% (P < 0.001). CONCLUSION: Thanks to the properties of tantalum, our modified single-portal TLIF technique is a valid surgical solution to obtain a solid arthrodesis and restore the correct lumbar lordosis distribution while reducing neurological complications and the number of failures. LEVEL OF EVIDENCE: 4 Trial registration statement: retrospective observational study, no trial registration.

Luteolin-loaded biocomposites containing tantalum and polyimide with antibacterial effects for facilitating osteogenic differentiation and bone bonding.

Polymer-based composites are considered promising candidates for bone repair as they possess some outstanding advantages over ceramic/metallic/polymeric biomaterials. Tantalum (Ta)/polyimide (PI) biocomposites (PT) containing 20 v% (PT20) and 40 v% (PT40) Ta nanoparticles were fabricated, and luteolin (LU) was loaded on PT40 (LUPT40). Compared with PT20 and PI, PT40 with a high Ta content displayed high surface behaviors (e.g., roughness, surface energy, and hydrophilicity). PT40 remarkably improved cell adhesion and multiplication, and LUPT40 with LU displayed further enhancement in vitro. Moreover, LUPT40 evidently boosted osteoblastic differentiation while suppressing osteoclastic differentiation. Furthermore, LUPT40 exhibited good antibacterial effects because of the slow release of LU. The in vivo results confirmed that PT40 markedly promoted bone formation and LUPT40 further enhanced bone formation/bone bonding. In brief, the incorporation of Ta particles improved the surface behaviors of PT40, which stimulated cell response/bone formation. Moreover, the slow release of LU from LUPT40 not only promoted cell response/bone formation but also enhanced bone bonding. The synergistic effects of Ta and LU release from LUPT40 enhanced bone formation/bone bonding. Therefore, LUPT40 would have great potential for the repair of bear-loading bone.

Optimize the pore size-pore distribution-pore geometry-porosity of 3D-printed porous tantalum to obtain optimal critical bone defect repair capability.

The treatment and reconstruction of large or critical size bone defects is a challenging clinical problem. Additive manufacturing breaks the technical difficulties of preparing complex conformation and anatomically matched personalized porous tantalum implants, but the ideal pore structure for 3D-printed porous tantalum in critical bone defect repair applications remains unclear. Guiding appropriate bone tissue regeneration by regulating proper pore size-pore distribution-pore geometry-porosity is a challenge for its fabrication and application. We fabricated porous tantalum (PTa) scaffolds with six different combinations of pore structures using powder bed laser melting (L-PBF) technology. In vitro biological experiments were conducted to systematically investigate the effects of pore structure characteristics on osteoblast behaviors, showing that the bionic trabecular structure with both large and small poress facilitated cell permeation, proliferation and differentiation compared to the cubic structure with uniform pore sizes. The osteogenesis of PTa with different porosity of trabecular structures was further investigated by a rabbit condyle critical bone defect model. Synthetically, T70% up-regulated the expression of osteogenesis-related genes (ALP, COLI, OCN, RUNX-2) and showed the highest bone ingrowth area and bone contact rate in vivo after 16 weeks, with the best potential for critical bone defect repair. Our results suggested that the bionic trabecular structure with a pore size distribution of 200-1200 µm, an average pore size of 700 µm, and a porosity of 70 % is the best choice for repairing critical bone defects, which is expected to guide the clinical application of clinical 3D-printed PTa scaffolds.

Excellent mid- to long-term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects.

PURPOSE: Severe metaphyseal bone defects remain a challenge and represent a growing problem in revision total knee arthroplasty (RTKA). The purpose of this study was to examine the survival of first-generation tantalum metal cones (TMC) and to assess clinical and radiographic data obtained from mid- to long-term follow-ups (FU) after RTKA with severe bony defects. METHODS: This retrospective case series included 100 consecutive patients of the same centre, who underwent RTKA surgery with TMC for tibia and/or femur bone defects between January 2011 and December 2015. Fourteen patients had died and six were lost for FU, leaving a total of eighty patients (one hundred and twelve TMC) for final evaluation. Clinical parameters including the Knee Society Score (KSS), visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were determined preoperatively based on the patients' medical charts, and assessed again during the final FU after an average of 6.1 (5-9) years postoperative. Standardised postoperative X-rays were analysed during the final FU visit for osseointegration of the cones, and any signs of implant loosening were assessed with the modified Knee Society Radiographic review criteria. Perioperative and postoperative complications, reoperations, as well as implant and cone re-revisions were analysed. Survivorship analysis was performed with (a) cone-related revision for any reason and (b) implant component revision for any reason. RESULTS: Previous RTKA had to be performed due to 64 (80%) aseptic and 16 (20%) septic failures. At the final FU, 75 (94%) tibia and 76 (95%) femur TMCs and implants were clinically stable. One patient experienced loosening of cones and implants at the femur and tibia but denied re-revision surgery. There were eight (10%) reoperations including two early wound healing problems, two inlay changes, two periprosthetic fractures, one debridement, antibiotics and implant retention (DAIR), and one secondary patella replacement. The six (7.5%) re-revisions included two aseptic loosening's of the opposite implant without TMC, one arthrodesis for recurrent instability, and three deep infections managed by two two-stage exchanges, and one amputation for persistent infection. At re-revision, all TMC cones were osteointegrated without signs of loosening. The determined clinical parameters showed significant (p < 0.001) postoperative improvement, and objective KSS was rated as excellent in 51%, and as good in 22% of patients at the final FU. The estimated 8-year Kaplan-Meier survival was 95% for TMC and 92.5% for implant components. CONCLUSION: Tantalum metal cones (TMC) demonstrate a secure fixation for treatment of severe femoral and tibial metaphyseal bone defects during RTKA. This fixation concept showed excellent mid- to long-term clinical and radiographic outcomes with promising 8-year survival rates for cones and implant components. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

Nano artificial periosteum PCL/Ta/ZnO accelerates repair of periosteum via antibacterial, promoting vascularization and osteogenesis.

The periosteum plays a critical role in bone development, shaping, remodeling, and fracture healing due to its abundance of osteoprogenitor cells, osteoblasts, and capillary network. However, the role of periosteum in bone injury healing has been underestimated, thus there is an urgent need to develop a multifunctional artificial periosteum that mimics the natural one. To tackle this issue, electrospinning technology was employed to fabricate an artificial periosteum composed of Poly-ε-caprolactone (PCL) doped with tantalum (Ta) and zinc oxide (ZnO) nanoparticles to enhance its antibacterial, osteogenic, and angiogenic properties. The in vitro cell experiments have demonstrated that the PCL/Ta/ZnO artificial periosteum exhibits excellent biocompatibility and can effectively facilitate osteogenic differentiation of BMSCs as well as angiogenic differentiation of EPCs. Antibacterial experiments have demonstrated the excellent bactericidal effects of PCL/Ta/ZnO artificial periosteum against both S. aureus and E. coli. The subcutaneous infection and critical-sized skull bone defect models have validated its in vivo properties of antibacterial activity, promotion of osteogenesis, and angiogenic potential. The PCL/Ta/ZnO artificial periosteum demonstrates remarkable efficacy in infection control and favorable immunomodulation, thereby achieving rapid vascularized bone repair. In conclusion, the utilization of PCL/Ta/ZnO tissue-engineered periosteum has been demonstrated to exhibit antibacterial properties, pro-vascularization effects, and promotion of osteogenesis at the site of bone defects. This promising approach could potentially offer effective treatment for bone defects.

Bioactivity and antibacterial properties of zinc-doped Ta2O5nanorods on porous tantalum surface.

This paper focuses on the preparation of Zn2+-doped Ta2O5nanorods on porous tantalum using the hydrothermal method. Porous tantalum is widely used in biomedical materials due to its excellent elastic modulus and biological activity. Porous tantalum has an elastic modulus close to that of human bone, and its large specific surface area is conducive to promoting cell adhesion. Zinc is an important component of human bone, which not only has spectral bactericidal properties, but also has no cytotoxicity. The purpose of this study is to provide a theoretical basis for the surface modification of porous tantalum and to determine the best surface modification method. The surface structure of the sample was characterized by x-ray diffractometer, x-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, and the Zn-doped Ta2O5nanorods are characterized by antibacterial test, MTT test, ICP and other methods. The sample has good antibacterial properties and no cytotoxicity. The results of this study have potential implications for the development of new and improved biomedical materials.

The bio-functionalized membrane loaded with Ta/WH nanoparticles promote bone regeneration through neurovascular coupling.

Electrospinning technology, as a novel approach, has been extensively applied in the field of tissue engineering. Nanofiber membranes prepared by electrospinning can effectively mimic the structure and function of natural bone matrix, providing an ideal scaffold for attachment, proliferation, and differentiation of bone cells while inducing osteogenic differentiation and new bone formation. However, it lacks bioactivities such as osteoinduction, angiogenesis and the ability to promote nerve regeneration. In the presence of complex critical bone defects, a single component electrospun membrane often fails to suffice for bone repair needs. Based on this, we prepared a biofunctionalized membrane loaded with Tantalum(Ta)/Whitlockite(WH) nanoparticles (poly-ε-caprolactone (PCL)/Ta/WH) in order to promote high-quality bone defect repair through neurovascular coupling effect. According to the results of in vitro and in vivo experiments, the early Mg2+ release of WH can effectively increase the local nerve and vascular density, and synergize with Tantalum nanoparticles (TaNPs) to create a rich nerve-vascular microenvironment. This allows the PCL/Ta/WH membrane to repair bone defects in multiple dimensions and achieve high-quality repair of bone tissue, providing new solutions for the treatment of critical bone defects in clinical.

Not So Similar: Different Ways of Nb(V) and Ta(V) Catecholate Complexation.

The reactions between catechol (H2cat) and niobium(V) or tantalum(V) precursors in basic aqueous solutions lead to the formation of catecholate complexes of different natures. The following complexes were isolated and characterized by single-crystal X-ray diffraction (SCXRD): (1) (NH4)3[NbO(cat)3]∙4H2O; (2) K2[Nb(cat)3(Hcat)]·2H2cat·2H2O; (3) Cs3[NbO(cat)3]·H2O; (4) (NH4)4[Ta2O(cat)6]·3H2O; (5) Cs2[Ta(cat)3(Hcat)]·H2cat; (6) Cs4[Ta2O(cat)6]·7H2O. The isolated crystalline products were characterized by elemental analysis, X-ray powder diffraction (XRPD), FTIR, and TGA. The structural features of these complexes, such as {Ta2O} unit geometry, Cs-π interactions, and crystal packing effects, are discussed.

Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware.

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

CT-based radiostereometric analysis for assessing midfoot kinematics: precision compared with marker-based radiostereometry.

BACKGROUND AND PURPOSE: 3-dimensional midfoot motion is hard to evaluate in clinical practice. We present a new computed tomography (CT)-based radiostereometric analysis (CT-RSA) technique to examine in vivo midfoot kinematics during single-leg stance and compare it with marker-based radiostereometry (RSA). PATIENTS AND METHODS: 8 patients were examined with bilateral non- and full-weight-bearing CT images of the midfoot. 1st tarsometatarsal motion was analyzed using a surface-registration technique (CT-RSA). As all patients had unilateral tantalum markers in the 1st cuneiform (C1) and 1st metatarsal (M1), comparison of precision with markerbased RSA was performed. CT-RSA precision was evaluated with surface registration of both C1-M1 bone and C1-M1 tantalum markers, while RSA precision was determined with C1-M1 markers only. Additionally, to remove motion bias, we evaluated intrasegmental CT-RSA precision by comparing proximal with distal part of M1. RESULTS: Under physical load, the primary movement for the 1st tarsometatarsal joint was M1 dorsiflexion (mean 1.4°), adduction (mean 1.4°), and dorsal translation (mean 1.1 mm). CT-RSA precision, using surface bone or markers, was in the range of 0.3-0.7 mm for translation and 0.6-1.6° for rotation. In comparison, RSA precision was in the range of 0.4-0.9 mm for translation and 1.0-1.7° for rotation. Finally, intrasegmental CT-RSA precision was in the range of 0.1-0.2 mm for translation and 0.4-0.5° for rotation. CONCLUSION: CT-RSA is a valid and precise, non-invasive method to measure midfoot kinematics when compared with conventional RSA.

Entropy optimization and response surface methodology of blood hybrid nanofluid flow through composite stenosis artery with magnetized nanoparticles (Au-Ta) for drug delivery application.

Entropy creation by a blood-hybrid nanofluid flow with gold-tantalum nanoparticles in a tilted cylindrical artery with composite stenosis under the influence of Joule heating, body acceleration, and thermal radiation is the focus of this research. Using the Sisko fluid model, the non-Newtonian behaviour of blood is investigated. The finite difference (FD) approach is used to solve the equations of motion and entropy for a system subject to certain constraints. The optimal heat transfer rate with respect to radiation, Hartmann number, and nanoparticle volume fraction is calculated using a response surface technique and sensitivity analysis. The impacts of significant parameters such as Hartmann number, angle parameter, nanoparticle volume fraction, body acceleration amplitude, radiation, and Reynolds number on the velocity, temperature, entropy generation, flow rate, shear stress of wall, and heat transfer rate are exhibited via the graphs and tables. Present results disclose that the flow rate profile increase by improving the Womersley number and the opposite nature is noticed in nanoparticle volume fraction. The total entropy generation reduces by improving radiation. The Hartmann number expose a positive sensitivity for all level of nanoparticle volume fraction. The sensitivity analysis revealed that the radiation and nanoparticle volume fraction showed a negative sensitivity for all magnetic field levels. It is seen that the presence of hybrid nanoparticles in the bloodstream leads to a more substantial reduction in the axial velocity of blood compared to Sisko blood. An increase in the volume fraction results in a noticeable decrease in the volumetric flow rate in the axial direction, while higher values of infinite shear rate viscosity lead to a significant reduction in the magnitude of the blood flow pattern. The blood temperature exhibits a linear increase with respect to the volume fraction of hybrid nanoparticles. Specifically, utilizing a hybrid nanofluid with a volume fraction of 3% leads to a 2.01316% higher temperature compared to the base fluid (blood). Similarly, a 5% volume fraction corresponds to a temperature increase of 3.45093%.