Insertion Pathway Research Articles

The clinical implications and cost-effectiveness of the provision of medical in addition to surgical catheter insertion for peritoneal dialysis in people with kidney failure.

High-quality and timely peritoneal access is essential for effective peritoneal dialysis (PD). Existing comparisons of medical compared to surgical catheter insertion have focused on the incidence of catheter events, but the cost-effectiveness of providing medical in addition to surgical catheter insertion in a dual pathway, compared to providing surgical insertion alone has not been evaluated. Data from the UK Catheter study, exploring how patient, service and insertion technique factors interact was used to estimate the comparative rates of catheter events between medical and surgical catheter insertion. A cost-effectiveness model estimates the health benefits and costs of providing medical in addition to surgical catheter insertion, compared to surgical insertion alone. Parametric modelling estimated time to catheter events, haemodialysis and transplantation to populate the model. Data on 769 first catheter insertions informs the model (325 medical and 444 surgical). Fewer catheter events were observed with medical insertion. The dual insertion pathway (69% medical, 31% surgical) was therefore associated with lower lifetime catheter events (3.18 vs. 3.34) and longer time on PD (3.07 vs. 3.00 years) than a purely surgical insertion pathway. The lifetime mean differences in quality-adjusted life years (7.12 vs. 7.00) and near identical costs (£226,549 vs. £226,764) meant dual insertion pathway was likely to be cost-effective, a finding robust to a series of sensitivity analyses. Offering medical in addition to surgical catheter insertion techniques has the potential to improve clinical outcomes and is likely to be highly cost-effective compared to surgical insertion alone.

Comparison of Lignocaine-Dexamethasone vs. Lignocaine-Triamcinolone for Preventing Post Spinal-Epidural Backache: A Randomized Study.

The primary objective of this study was to compare the efficacy of lignocaine-dexamethasone and lignocaine-triamcinolone infiltration, along the spinal-epidural needle insertion pathway, to prevent backache after lower abdominal surgeries. This prospective, double-blind randomized controlled study included a total of 150 patients, scheduled for elective lower abdominal surgery undercombined spinal-epidural (CSE) anaesthesia. The patients were randomised into three groups Group L (Lignocaine, n=50), Group DL (Dexamethasone, Lignocaine, n=50), and Group TL (Triamcinolone, Lignocaine, n=50). The Visual Analogue Score (VAS) was used to assess the postoperative pain. The anthropometric and demographic findings were comparable among the three groups. The mean VAS score at the time points of needle placement and at postoperative time periods of 24 hours, 48 hours, 72 hours, one month, two months and three months were significantly lower (p<0.001) in groups DL and TL compared to group L. This study demonstrated that the addition of a steroid like triamcinolone or dexamethasone with lignocaine for local infiltration along the spinal-epidural tract significantly lowers the severity of post-needle puncture backache in comparison to lignocaine alone in lower abdominal surgeries.

Dynamic Lithium Transport Pathway via Crack Formation in Phase-Separating Materials

Degradation of electrode particles during cycling is chemo-mechanically coupled and needs to be systematically investigated for the Li-ion battery development. The effect of Li transport pathway on internal stress and crack formation during cycling remains elusive. The opposite effect of cracked, newly exposed active surface on Li transport pathway alteration, accelerating the chemo-mechanical degradation, also remains poorly known. Using operando scanning transmission X-ray microscopy on [100]-oriented LiFePO4 single particles, we demonstrated that lithium insertion from the edge of the non-cracked particle dynamically generate tensile stress within the particle, thereby initiating crack formation during lithiation. The exposed crack surface acts as a Li (de)insertion hotspot, redirecting Li transport pathway and internal stress-fields. Delithiation process induces the Li-poor phase around the crack, creating tensile stress, propagating the crack, and subsequently exposing fresh surface which serves as active hot-spot. On the other hands, lithiation process induces the Li-rich phases around the crack, creating compressive stress and suppressing crack propagation. Phase-field simulations demonstrate chemo-mechanically interactive loop that lithium (de)insertion pathway determines dynamic tensile/compressive stress distribution, which recursively determines (de)insertion pathway. This study offers insights that can help develop high-performance and long-lasting batteries, as well as cycling protocols that suppress crack formation. Figure 1

(Invited) How Interfaces Control Lithium (De)insertion Pathway: Comparing Liquid and Solid Electrolytes

In the realm of lithium-ion batteries, the process of lithium (de)insertion follows a two-fold pathway, encompassing (1) charge transfer occurring at the electrolyte-electrode interface and (2) solid-state lithium diffusion within electrode. Conventionally, these two transport mechanisms have been regarded as distinct and investigated separately due to their sequential occurrence during battery cycling. However, our recent research demonstrates that the kinetics of charge transfer can exert control over the spatial distribution of lithium on the surface, consequently influencing the entire lithium (de)insertion pathway.In addition, in the field of all-solid-state batteries (ASSBs), the interface between solid-electrolytes and electrodes further modulates the surface charge transfer kinetics, active surface areas, and local stresses. Chemo-mechanical properties in ASSBs complicate interfacial charge transfer and further affect lithium diffusion within the electrodes. In this talk, I will present how our synchrotron-based operando X-ray diffraction and imaging could help understand such phenomena.

Sustainable waste-treating-waste strategy: Catalytic recycling of polyethylene terephthalate over reconstructed waste catalysts

Polyethylene terephthalate (PET) is the most widely used polyester plastic, but difficulties associated with PET recycling have led to significant environmental issues. The recycling of PET waste into building monomers and valuable chemicals has attracted increasing attention. Herein, we propose a sustainable circular strategy for efficiently hydrogenolytic depolymerizing the waste PET by using reconstructed spent catalysts from the heavy oil slurry-phase hydrocracking. Two types of molybdenum sulphide/activated petroleum-based carbon compounds, a-MoSx/APC and MoS2/APC, were constructed using waste refining catalyst through the activation and annealing methods, which were used as catalysts for the hydrogenolytic depolymerisation of waste PET. Experimental results revealed that the different active components in the two reconstructed catalysts, molybdenum sulphide clusters, and few-layered molybdenum disulfide, show different activity and selectivity for the catalytic depolymerisation of PET. After the β-scission process of PET, the formed intermediate vinyl-terminated carboxylate units are converted to monoethyl terephthalate (MET) through a CC insertion pathway catalyzed by MoV, while to terephthalic acid (TPA) through a hydrogenolysis pathway catalyzed by MoIV. Therefore, MoS2/APC converts PET to TPA with a yield of 83 % within 24 hours at 270 °C under 1 atmosphere of H2 and solvent-free conditions, without generating any MET products. Moreover, this process is effective for both commercial and waste PET, and the catalyst could be reused for at least ten runs with stable activity. The sustainable waste-treating-waste strategy highlights a potential approach to the circular economy.

Kinetic Studies of CO2 Insertion into Metal-Element σ-Bonds.

ConspectusDespite the plethora of metal catalyzed reactions for CO2 utilization that have been developed in academic laboratories, practical systems remain elusive. The understanding of the elementary steps in catalysis is a proven method to improve catalytic performance. In many catalytic cycles for CO2 utilization, the insertion of CO2 into a metal-element σ-bond, such as hydrides, alkyls, amides, or hydroxides, is a crucial step. However, despite the many demonstrations of CO2 insertion, there are a paucity of kinetic studies, and information about the reaction mechanism has been predominantly elucidated from computational investigations. In this Account, kinetic studies on CO2 insertion into late transition metal-element σ-bonds performed by my group are summarized, along with their implications for catalysis.A common pathway for CO2 insertion into a metal hydride involves a two-step mechanism. The first step is nucleophilic attack on CO2 by the hydride to generate an H-bound formate, followed by rearrangement to form an O-bound formate product. Kinetic studies on systems in which both the first and second steps are proposed to be rate-determining, known as inner-sphere and outer-sphere processes, respectively, show that insertion rates increase as (i) the ligand trans to the hydride becomes a stronger donor, (ii) the ancillary ligand becomes more electron-donating, and (iii) the Dimroth-Reichardt parameter of the solvent increases. However, the magnitude of these effects is generally smaller for inner-sphere processes because there is less buildup of charge in the key transition state. For similar reasons, the presence of Lewis acids only increases the rate of outer-sphere processes. These results suggest it may be possible to experimentally differentiate between inner- and outer-sphere processes.The insertion of CO2 into a metal-alkyl bond results in the formation of a C-C bond, which is important for the generation of fuels from CO2. For square planar Group 10 complexes, the presence of a strong donor ligand trans to the alkyl group is critical for kinetically promoting insertion. Further, the nucleophilicity of the alkyl ligand directly impacts the rate of CO2 insertion via an SE2 mechanism, as does the steric bulk of the complex, and the reaction solvent. In contrast to the relatively slow rates of insertion observed for metal alkyls, CO2 insertion is rapid for metal hydroxides and amides. Although kinetics trends could be determined for hydroxides, reactions with amides are too fast for quantitative studies.Overall, the rates of insertion correlate with the nucleophilicity of the element in the metal-element σ-bond, so amide > hydroxide > hydride > alkyl. Due to the related pathways for insertion, similar trends in ligand and solvent effects are observed for insertion into different metal-element σ-bonds. Thus, the same strategies can be used to control the rates of insertion across systems. Differences in the magnitude of solvent and ligand effects are caused by variation in the amount of charge build-up on the metal in the rate-determining transition state. Likely, given that CO2 is related to organic molecules such as aldehydes, ketones, and amides, the results described in this Account are general to a wider range of substrates.

Clinical Outcomes for Arthroscopic Anterior Talofibular Ligament Repair After Suture Anchor Insertion Through the Anterolateral Portal vs the Lateral Accessory Portal.

Two types of suture anchor insertion pathways (anterolateral portal vs lateral accessory portal) are used in arthroscopic anterior talofibular ligament (ATFL) repair. However, it is not clear which one is the better choice. This study aims to compare the clinical outcomes of these 2 suture anchor insertion pathways when performing arthroscopic ATFL lasso-loop repair for the treatment of chronic lateral ankle instability (CLAI). From 2019 to 2021, patients with CLAI who underwent arthroscopic ATFL lasso-loop repair were retrospectively reviewed and divided into the anterolateral portal (ALP) group and the lateral accessory portal (LAP) group. A 1:1 propensity score matching was used to control confounding factors based on age, sex, body mass index, follow-up duration, preoperative visual analog scale (VAS) score, and Tegner score (ALP group, n = 26; LAP group, n = 26). Karlsson score, VAS score, Tegner score, operation time, anterior drawer test results, patient symptoms, and magnetic resonance (MR) evaluation of ATFL quality were used to describe the outcomes. The patient characteristics and follow-up durations were similar between the 2 groups. After a mean follow-up duration of 28.8 ± 2.3 months, the ALP group had significantly better Karlsson score, VAS score, and Tegner score improvement than the LAP group, with fewer symptoms. Seven patients in the LAP group still had a feeling of ankle instability, and 3 of them exhibited ankle laxity. In this study, we found that inserting the suture anchor through the anterolateral portal was associated with better outcomes compared to that through the lateral accessory portal when performing arthroscopic ATFL lasso-loop repair for CLAI patients. The improvement was greater for pain relief and function and was associated with a lower frequency of subjective ankle instability.

The Pathway of a Transmembrane Helix Insertion into the Membrane Assisted by Sec61α Channel.

The significant inconsistency between the experimental and simulation results of the free energy for the translocon-assisted insertion of the transmembrane helix (TMH) has not been reasonably explained. Understanding the mechanism of TMH insertion through the translocon is the key to solving this problem. In this study, we performed a series of coarse-grained molecular dynamics simulations and calculated the potential mean forces (PMFs) for three insertion processes of a hydrophobic TMH. The simulations reveal the pathway of the TMH insertion assisted by a translocon. The results indicate that the TMH contacts the top of the lateral gate first and then inserts down the lateral gate, which agrees with the sliding model. The TMH begins to transfer laterally to the bilayer when it is blocked by the plug and reaches the exit of the lateral gate, where there is a free energy minimum point. We also found that the connecting section between TM2 and TM3 of Sec61α prevented TMH from leaving the lateral gate and directly transitioning to the surface-bound state. These findings provide insight into the mechanism of the insertion of TMH through the translocon.

Kinetic Isotope Effects and the Mechanism of CO2 Insertion into the Metal-Hydride Bond of fac-(bpy)Re(CO)3H.

The 1,2-insertion reaction of CO2 into metal-hydride bonds of d6-octahedral complexes to give κ1-O-metal-formate products is the key step in various CO2 reduction schemes and as a result has attracted extensive mechanistic investigations. For many octahedral catalysts, CO2 insertion follows an associative mechanism in which CO2 interacts directly with the coordinated hydride ligand instead of the more classical dissociative mechanism that opens an empty coordination site to bind the substrate to the metal prior to a hydride migration step. To better understand the associative mechanism, we conducted a systematic quantum chemical investigation on the reaction between CO2 and fac-(bpy)Re(CO)3H (1-Re-H; bpy = 2,2'-bipyridine) starting with the gas phase and then moving to THF and other solvents with increased dielectric constants. Detailed analyses of the potential energy surfaces (PESs) and intrinsic reaction coordinates (IRCs) reveal that the reaction is enabled in all media by an initial stage of making a 3c-2e bond between the carbon of CO2 and the metal-hydride bond that is most consistent with an organometallic bridging hydride Re-H-CO2 species. Once CO2 is bent and anchored to the metal-hydride bond, the reaction proceeds by a rotation motion via a cyclic transition state TS2 that interchanges Re-H-CO2 and Re-O-CHO coordination. The combined stages provide an asynchronous-concerted pathway for CO2 insertion on the Gibbs free energy surface with TS2 as the highest energy point. Consideration of TS2 as a rate-determining TS gives activation barriers, inverse KIEs, substituent effects, and solvent effects that agree with the experimental data available in this system. An important new insight revealed by the analyses of the results is that the initial stage of the reaction is not a hydride transfer step as has been assumed in some studies. In fact, the loose vibration of the TS that can be identified for the first stage of the reaction in solution (TS1) does not involve the Re-H stretching vibrational mode. Accordingly, the imaginary frequency of TS1 is insensitive to deuteration, and therefore, TS1 leads to no significant KIE.

Design of symmetric supercapacitor based on Co3O4/Carboxymethyl cellulose nanoflakes with excellent cyclic stability

An advanced electrode material having fine micro/nano-architecture that provide unique qualities like ultra-high charge storage capabilities, high specific area and efficient pathway for ion insertion will always have superior position in the energy sphere. The prime motive of the present work is to fabricate carboxymethyl cellulose (CMC) encapsulated cobalt oxide nanoflakes as pioneered electrodes for supercapacitors. Utilizing a Faradaic candidate (cobalt oxide), which traps charges abundantly that leads to attracting capacitance (381 F g−1 at a specific current of 1 A g−1) with least charge transfer resistance (0.87 Ω). Make use of CMC as host that supports the composite via providing admirable cyclic life (100 % capacitance retention even after 5000 continuous charge/discharge cycles). Un-interrupted charge delivery that probably attributed to the formation of flaky architecture of cobalt oxide which was encapsulated by carbon matrix. As the end, a symmetric supercapacitor was designed using Co3O4/C nanoflakes as both positive and negative electrode. The fabricated two cell could capable of maintaining its stability of 95.87 % from its initial value after 5000 cycles of charge and discharge at a practical current density of 20 A g−1. The outcomes of the present study (three and two cell configuration as well) will open new gateways in energy regime for next generation supercapacitors.

Protein insertion into the inner membrane of mitochondria: routes and mechanisms.

The inner membrane of mitochondria contains hundreds of different integral membrane proteins. These proteins transport molecules into and out of the matrix, they carry out multifold catalytic reactions and they promote the biogenesis or degradation of mitochondrial constituents. Most inner membrane proteins are encoded by nuclear genes and synthesized in the cytosol from where they are imported into mitochondria by translocases in the outer and inner membrane. Three different import routes direct proteins into the inner membrane and allow them to acquire their appropriate membrane topology. First, mitochondrial import intermediates can be arrested at the level of the TIM23 inner membrane translocase by a stop-transfer sequence to reach the inner membrane by lateral insertion. Second, proteins can be fully translocated through the TIM23 complex into the matrix from where they insert into the inner membrane in an export-like reaction. Carriers and other polytopic membrane proteins embark on a third insertion pathway: these hydrophobic proteins employ the specialized TIM22 translocase to insert from the intermembrane space (IMS) into the inner membrane. This review article describes these three targeting routes and provides an overview of the machinery that promotes the topogenesis of mitochondrial inner membrane proteins.

Impact of osteosclerosis on cervical pedicle screw insertion using preoperative CT-based navigation.

Preoperative computed tomography (CT)-based navigation is used for cervical pedicle screw (CPS) insertion to mitigate the risk of spinal cord and vertebral artery injury. In vertebrae with osteosclerosis due to degeneration or other factors, however, probing may not proceed easily, with difficulty creating the CPS insertion hole. This study investigated the impact of osteosclerosis on the accuracy of CPS insertion. A total of 138 patients with CPS inserted at the C3-C7 level using preoperative CT navigation were retrospectively analyzed. Pre- and postoperative CT was employed to investigate screw position and Hounsfield unit (HU) values at the lateral mass to evaluate the degree of osteosclerosis in the CPS insertion pathway. Among 561 CPS insertions, the Grade 3 perforation rate was 1.8%, and the Grade 2 or higher perforation rate was 8.0%. When comparing insertions with and without CPS perforation, HU values were significantly higher in the perforation group (578 ± 191 vs. 318 ± 191, p < 0.01). The frequency of CPS insertion into the mid-cervical spine was also significantly greater in the perforation group (68.9% vs. 62.5%, p < 0.01). Logistic regression analysis revealed that a high HU value at the lateral mass (odds ratio 1.09, 95% confidence interval: 1.07-1.11, p < 0.01) was a significant independent factor associated with CPS deviation. The screw perforation rate of Grade 2 or higher in CPS insertion using preoperative CT-based navigation was 8.0%. Since osteosclerosis was an independent factor related to CPS deviation, additional care may be required during insertion into affected vertebrae.

Observation of geometric phase effect through backward angular oscillations in the H + HD → H2 + D reaction

Quantum interference between reaction pathways around a conical intersection (CI) is an ultrasensitive probe of detailed chemical reaction dynamics. Yet, for the hydrogen exchange reaction, the difference between contributions of the two reaction pathways increases substantially as the energy decreases, making the experimental observation of interference features at low energy exceedingly challenging. We report in this paper a combined experimental and theoretical study on the H + HD → H2 + D reaction at the collision energy of 1.72 eV. Although the roaming insertion pathway constitutes only a small fraction (0.088%) of the overall contribution, angular oscillatory patterns arising from the interference of reaction pathways were clearly observed in the backward scattering direction, providing direct evidence of the geometric phase effect at an energy of 0.81 eV below the CI. Furthermore, theoretical analysis reveals that the backward interference patterns are mainly contributed by two distinct groups of partial waves (J ~ 10 and J ~ 19). The well-separated partial waves and the geometric phase collectively influence the quantum reaction dynamics.

Comprehensive Evaluation of Models for Ammonia Binding to the Oxygen Evolving Complex of Photosystem II.

The identity and insertion pathway of the substrate oxygen atoms that are coupled to dioxygen by the oxygen-evolving complex (OEC) remains a central question toward understanding Nature's water oxidation mechanism. In several studies, ammonia has been used as a small "water analogue" to elucidate the pathway of substrate access to the OEC and to aid in determining which of the oxygen ligands of the tetramanganese cluster are substrates for O-O bond formation. On the basis of structural and spectroscopic investigations, five first-sphere binding modes of ammonia have been suggested, involving either substitution of an existing H2O/OH-/O2- group or addition as an extra ligand to a metal ion of the Mn4CaO5 cluster. Some of these modes, specifically the ones involving substitution, have already been subject to spectroscopy-oriented quantum chemical investigations, whereas more recent suggestions that postulate the addition of ammonia have not been examined so far with quantum chemistry for their agreement with spectroscopic data. Herein, we use a common structural framework and theoretical methodology to evaluate structural models of the OEC that represent all proposed modes of first-sphere ammonia interaction with the OEC in its S2 state. Criteria include energetic, magnetic, kinetic, and spectroscopic properties compared against available experimental EPR, ENDOR, ESEEM, and EDNMR data. Our results show that models featuring ammonia replacing one of the two terminal water ligands on Mn4 align best with experimental data, while they definitively exclude substitution of a bridging μ-oxo ligand as well as incorporation of ammonia as a sixth ligand on Mn1 or Mn4.

The implementation of a pectus bar insertion enhanced recovery after surgery pathway: A quality improvement initiative.

Pectus excavatum repair is associated with significant discomfort, and pain is a primary contributor to postoperative hospital length of stay. Recent advances in postoperative pain control include the use of intercostal cryoablation techniques that may now make it possible to discharge patients on the day of surgery. Unnecessary variation in patient care and noncompliance with care bundles may be a factor in extended length of stay. The global aim of this quality improvement initiative was to successfully implement an enhanced recovery after surgery (ERAS) pathway on patients undergoing pectus excavatum repair. The SMART aim was to have a greater than 70% compliance for the perioperative bundle elements within 1 year of the pathway implementation. Multiple Plan-Do-Study-Act (PDSA) cycles were designed to create and implement an ERAS pathway for patients undergoing a pectus bar insertion procedure. This multidisciplinary pathway was designed, managed, and implemented with key stakeholders from the Departments of Evidence Based Practice, Surgery, Anesthesiology, and Perioperative Nursing. Patient characteristics, outcomes, and compliance with elements of the pathway were measured for analysis for both the baseline and post-intervention groups with monthly automated reports. After implementation of the ERAS pathway, data on the first 50 patients showed a 90% compliance with the perioperative bundle elements. Mean length of stay was significantly decreased from 33 h (95% CI [28.76, 37.31]) to 18 h (95% CI [14.54, 21.70]). There were zero readmissions within 24 hours for patients who were discharged on the day of surgery. Employing a multidisciplinary approach in both planning and execution that standardized clinician practices and minimized unnecessary variation in patient care, an ERAS pathway for pectus bar insertion has been successfully established at our institution.

Oxy- and Chloroarylation Pathways in Gold-Mediated Cyclization of 2-Aminoaryl-3-arylpropargyl-benzenesulfonamides.

A one-pot diazotization/gold-mediated cyclization of 2-aminoaryl-3-arylpropargyl-benzenesulfonamides is described. After diazotization, Me2 SAuCl triggers an oxy- and/or chloroarylation of the alkyne moiety, resulting in the formation of 3-acylindoles and/or Z-3-(chloromethylene)indolines. Density Functional Theory (DFT) calculations show the significant energetic preference of both processes over an insertion pathway. Notably, a Z-3-(chloromethylene)indoline crystallized with [Cl-Au-Cl],- exhibiting Au⋅⋅⋅H-C short contacts.

Dearomative Ring‐Fused Azafulleroids and Carbazole‐Derived Metallofullerenes: Reactivity Dictated by Encapsulation in a Fullerene Cage

AbstractHerein, we report divergent additions of 2,2′‐diazidobiphenyls to C60 and Sc3N@Ih‐C80. In stark contrast to that of the previously reported bis‐azide additions, the unexpected cascade reaction leads to the dearomative formation of azafulleroids 2 fused with a 7‐6‐5‐membered ring system in the case of C60. In contrast, the corresponding reaction with Sc3N@Ih‐C80 switches to the C−H insertion pathway, thereby resulting in multiple isomers, including a carbazole‐derived [6,6]‐azametallofulleroid 3 and a [5,6]‐azametallofulleroid 4 and an unusual 1,2,3,6‐tetrahydropyrrolo[3,2‐c]carbazole‐derived metallofullerene 5, whose molecular structures have been unambiguously determined by single‐crystal X‐ray diffraction analyses. Among them, the addition type of 5 is observed for the first time in all reported additions of azides to fullerenes. Furthermore, unexpected isomerizations from 3 to 5 and from 4 to 5 have been discovered, providing the first examples of the isomerization of an azafulleroid to a carbazole‐derived fullerene rather than an aziridinofullerene. In particular, the isomerism of the [5,6]‐isomer 4 to the [5,6]‐isomer 5 is unprecedented in fullerene chemistry, contradicting the present understanding that isomerization generally occurs between [5,6]‐ and [6,6]‐isomers. Control experiments have been carried out to rationalize the reaction mechanism. Furthermore, representative azafulleroids have been applied in organic solar cells, thereby resulting in improved power conversion efficiencies.

Dearomative Ring-Fused Azafulleroids and Carbazole-Derived Metallofullerenes: Reactivity Dictated by Encapsulation in a Fullerene Cage.

Herein, we report divergent additions of 2,2'-diazidobiphenyls toward C60 and Sc3N@Ih-C80. In stark contrast to that of the previously reported bis-azide additions, the unexpected reactivity leads to the cascade dearomative formation of unprecedented azafulleroids 2 fused with a 7-6-5-membered ring system in the case of C60. In contrast, the corresponding reaction with Sc3N@Ih-C80 switches to the cascade C-H insertion pathway, resulting in multiple isomers, including a carbazole-derived [6,6]-azametallofulleroid 3 and a [5,6]-azametallofulleroid 4 and an unusual 1,2,3,6-tetrahydropyrrolo[3,2-c]carbazole-derived metallofullerene 5, whose molecular structures have been unambiguously determined by single crystal X-ray diffraction analyses. Among them, the addition type of 5 is observed for the first time in all reported additions of azides to fullerenes. Furthermore, unexpected isomerizations from 3 to 5 and from 4 to 5 have been discovered, representing the first example of isomerization from an azafulleroid to a carbazole-derived fullerene rather than an aziridinofullerene. In particular, the isomerism from [5,6]-isomer 4 to [5,6]-isomer 5 is unprecedented in fullerene chemistry, contradicting the present understanding that isomerization generally occurs between [5,6]- and [6,6]-isomers. Control experiments have been carried out to rationalize the reaction mechanism. Furthermore, representative azafulleroids have been applied in organic solar cells, resulting in improved power conversion efficiency.

Three-Dimensional Quantitative Assessment of Pedicle Screw Accuracy in Clinical Utilization of a New Robotic System in Spine Surgery: A Multicenter Study.

The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery. A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.). Intraoperative O-arm images were obtained, and screw insertion pathways were planned accordingly. Image registration was performed using paired-point registration and iterative closest point methods. The accuracy of the robotic-guided pedicle screw insertion was assessed using 3-dimensional offset calculation and the Gertzbein-Robbins system (GRS). A total of 448 screws were inserted in the 113 patients. The image registration success rate was 95.16%. The average error of entry offset was 2.86 mm, target offset was 2.48 mm, depth offset was 1.99 mm, and angular offset was 3.07°. According to the GRS grading system, 88.39% of the screws were classified as grade A, 9.60% as grade B, 1.56% as grade C, 0.22% as grade D, and 0.22% as grade E. Clinically acceptable screws (GRS grade A or B) accounted for 97.54% of the total, with no reported neurologic complications. Our study demonstrated that pedicle screw insertion using the novel robot-assisted navigation method is both accurate and safe. Further prospective studies are necessary to explore the potential benefits of this robot-assisted technique in comparison to conventional approaches.

Catheter Event Rates in Medical Compared to Surgical Peritoneal Dialysis Catheter Insertion

How patient, center, and insertion technique factors interact needs to be understood when designing peritoneal dialysis (PD) catheter insertion pathways. We undertook a prospective cohort study in 44 UK centers enrolling participants planned for first catheter insertion. Sequences of regressions were used to describe the associations linking patient and dialysis unit-level characteristics with catheter insertion technique and their impact on the occurrence of catheter-related events in the first year (catheter-related infection, hospitalization, and removal). Factors associated with catheter events were incorporated into a multistate model comparing the rates of catheter events between medical and surgical insertion alongside treatment modality transitions and mortality. Of 784 first catheter insertions, 466 (59%) had a catheter event in the first year and 61.2% of transitions onto hemodialysis (HD) were immediately preceded by a catheter event. Catheter malfunction was less but infection was more common with surgical compared with medical insertions. Participants at centers with fewer late presenters and more new dialysis patients starting PD, had a lower probability of a catheter event. Adjusting for these factors, the hazard ratio for a catheter event following insertion (medical vs. surgical) was 0.70 (95% confidence interval [CI] 0.43 to 1.13), and once established on PD 0.77 (0.62 to 0.96). Offering both medical and surgical techniques is associated with lower catheter event rates and keeps people on PD for longer.