Reactivity of E4_4 (E4_4 =P4_4 , As4_4 , AsP3_3) towards Low‐Valent Al(I) and Ga(I) Compounds

The reactivity of yellow arsenic and the interpnictogen compound AsP$_3$ towards low-valent group 13 compounds was investigated. The reactions of [LAl] (1, L=[{N(C$_6$H$_3$$^i$Pr$_2$-2,6)C(Me)}$_2$CH]−) with As$_4$ and AsP$_3$ lead to [(LAl)$_2$(μ,η$^{1:1:1:1}$-E$_4$)] (E$_4$=As$_4$ (3 b), AsP$_3$ (3 c)) by insertion of two fragments [LAl] into two of the six E−E edges of the E$_4$ tetrahedra. Furthermore, the reaction of [LGa] (2) with E$_4$ afforded [LGa(η$^{1:1}$-E$_4$)] (E$_4$=As$_4$ (4 b), AsP$_3$ (4 c)). In these compounds, only one E−E bond of the E$_4$ tetrahedra was cleaved. These compounds represent the first examples of the conversion of yellow arsenic and AsP$_3$, respectively, with group 13 compounds. Furthermore, the reactivity of the gallium complexes towards unsaturated transition metal units or polypnictogen (E$_n$) ligand complexes was investigated. This leads to the heterobimetallic compounds [(LGa)(μ,η$^{2:1:1}$-P$_4$)(LNi)] (5 a), [(Cp’’’Co)(μ,η$^{4:1:1}$-E$_4$)(LGa)] (E=P (6 a), As (6 b), Cp’’’=η$^5$-C$_5$H$_2$$^t$Bu$_3$) and [(Cp’’’Ni)(η$^{3:1:1}$-E$_3$)(LGa)] (E=P (7 a), As (7 b)), which combine two different ligand systems in one complex (nacnac and Cp) as well as two different types of metals (main group and transition metals). The products were characterized by crystallographic and spectroscopic methods

Reactivity of E ₄ (E ₄ =P ₄ , As ₄ , AsP ₃ ) towards Low‐Valent Al(I) and Ga(I) Compounds

The reactivity of yellow arsenic and the interpnictogen compound AsP3 towards low-valent group 13 compounds was investigated. The reactions of [LAl] (1, L=[{N(C6H3iPr2-2,6)C(Me)}2CH]−) with As4 and AsP3 lead to [(LAl)2(μ,η1:1:1:1-E4)] (E4=As4 (3 b), AsP3 (3 c)) by insertion of two fragments [LAl] into two of the six E−E edges of the E4 tetrahedra. Furthermore, the reaction of [LGa] (2) with E4 afforded [LGa(η1:1-E4)] (E4=As4 (4 b), AsP3 (4 c)). In these compounds, only one E−E bond of the E4 tetrahedra was cleaved. These compounds represent the first examples of the conversion of yellow arsenic and AsP3, respectively, with group 13 compounds. Furthermore, the reactivity of the gallium complexes towards unsaturated transition metal units or polypnictogen (En) ligand complexes was investigated. This leads to the heterobimetallic compounds [(LGa)(μ,η2:1:1-P4)(LNi)] (5 a), [(Cp’’’Co)(μ,η4:1:1-E4)(LGa)] (E=P (6 a), As (6 b), Cp’’’=η5-C5H2tBu3) and [(Cp’’’Ni)(η3:1:1-E3)(LGa)] (E=P (7 a), As (7 b)), which combine two different ligand systems in one complex (nacnac and Cp) as well as two different types of metals (main group and transition metals). The products were characterized by crystallographic and spectroscopic methods

Binding, Release and Functionalization of Intact Pnictogen Tetrahedra Coordinated to Dicopper Complexes

The bridging MeCN ligand in the dicopper(I) complexes [(DPFN)Cu2(μ,η1 : η1-MeCN)][X]2 (X=weakly coordinating anion, NTf2 (1 a), FAl[OC6F10(C6F5)]3 (1 b), Al[OC(CF3)3]4 (1 c)) was replaced by white phosphorus (P4) or yellow arsenic (As4) to yield [(DPFN)Cu2(μ,η2 : η2-E4)][X]2 (E=P (2 a–c), As (3 a–c)). The molecular structures in the solid state reveal novel coordination modes for E4 tetrahedra bonded to coinage metal ions. Experimental data and quantum chemical computations provide information concerning perturbations to the bonding in coordinated E4 tetrahedra. Reactions with N-heterocyclic carbenes (NHCs) led to replacement of the E4 tetrahedra with release of P4 or As4 and formation of [(DPFN)Cu2(μ,η1 : η1-MeNHC)][X]2 (4 a,b) or to an opening of one E−E bond leading to an unusual E4 butterfly structural motif in [(DPFN)Cu2(μ,η1 : η1-E4DippNHC)][X]2 (E=P (5 a,b), E=As (6)). With a cyclic alkyl amino carbene (EtCAAC), cleavage of two As−As bonds was observed to give two isomers of [(DPFN)Cu2(μ,η2 : η2-As4EtCAAC)][X]2 (7 a,b) with an unusual As4-triangle+1 unit

Development and evaluation of an image-free computer-assisted impingement detection technique for total hip arthroplasty

Periprosthetic or bony impingement in total hip arthroplasty (THA) has been correlated to dislocation, increased wear, reduced postoperative functionality with pain and/or decreased range of motion (ROM). We sought to study the accuracy and assess the reliability of measuring bony and periprosthetic impingement on a virtual bone model prior to the implantation of the acetabular cup with the help of image-free navigation technology in an experimental cadaver study. Impingement-free ROM measurements were recorded during minimally invasive, computer-assisted THA on 14 hips of 7 cadaveric donors. Preoperatively and postoperatively the donors were scanned using computed tomography (CT). Impingement-free ROM on three-dimensional CT-based models was then compared with corresponding, intraoperative navigation models. Bony/periprosthetic impingement can be detected with a mean accuracy limit of below 5° for motion angles, which should be reached after THA for activities of daily living with the help of image-free navigation technology

Similar complication rates for irreversible electroporation and thermal ablation in patients with hepatocellular tumors

Background. To compare the frequency of adverse events of thermal microwave (MWA) and radiofrequency ablation (RFA) with non-thermal irreversible electroporation (IRE) in percutaneous ablation of hepatocellular carcinoma (HCC). Patients and methods. We retrospectively analyzed 117 MWA/RFA and 47 IRE procedures (one tumor treated per procedure; 144 men and 20 women; median age, 66 years) regarding adverse events, duration of hospital and intensive care unit (ICU) stays and occurrence of a post-ablation syndrome. Complications were classified according to the Clavien & Dindo classification system. Results. 70.1% of the RFA/MWA and 63.8% of the IRE procedures were performed without complications. Grade I and II complications (any deviation from the normal postinterventional course, e.g., analgesics) occurred in 26.5% (31/117) of MWA/RFA and 34.0% (16/47) of IRE procedures. Grade III and IV (major) complications occurred in 2.6% (3/117) of MWA/RFA and 2.1% (1/47) of IRE procedures. There was no significant difference in the frequency of complications (p = 0.864), duration of hospital and ICU stay and the occurrence of a post-ablation syndrome between the two groups. Conclusions. Our results suggest that thermal (MWA and RFA) and non-thermal IRE ablation of malignant liver tumors have comparable complication rates despite the higher number of punctures and the lack of track cauterization in IRE

Minimally invasive computer-navigated total hip arthroplasty, following the concept of femur first and combined anteversion: design of a blinded randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Impingement can be a serious complication after total hip arthroplasty (THA), and is one of the major causes of postoperative pain, dislocation, aseptic loosening, and implant breakage. Minimally invasive THA and computer-navigated surgery were introduced several years ago. We have developed a novel, computer-assisted operation method for THA following the concept of "femur first"/"combined anteversion", which incorporates various aspects of performing a functional optimization of the cup position, and comprehensively addresses range of motion (ROM) as well as cup containment and alignment parameters. Hence, the purpose of this study is to assess whether the artificial joint's ROM can be improved by this computer-assisted operation method. Second, the clinical and radiological outcome will be evaluated.</p> <p>Methods/Design</p> <p>A registered patient- and observer-blinded randomized controlled trial will be conducted. Patients between the ages of 50 and 75 admitted for primary unilateral THA will be included. Patients will be randomly allocated to either receive minimally invasive computer-navigated "femur first" THA or the conventional minimally invasive THA procedure. Self-reported functional status and health-related quality of life (questionnaires) will be assessed both preoperatively and postoperatively. Perioperative complications will be registered. Radiographic evaluation will take place up to 6 weeks postoperatively with a computed tomography (CT) scan. Component position will be evaluated by an independent external institute on a 3D reconstruction of the femur/pelvis using image-processing software. Postoperative ROM will be calculated by an algorithm which automatically determines bony and prosthetic impingements.</p> <p>Discussion</p> <p>In the past, computer navigation has improved the accuracy of component positioning. So far, there are only few objective data quantifying the risks and benefits of computer navigated THA. Therefore, this study has been designed to compare minimally invasive computer-navigated "femur first" THA with a conventional technique for minimally invasive THA. The results of this trial will be presented as soon as they become available.</p> <p>Trial registration number</p> <p>DRKS00000739</p

Neuromatch Academy: a 3-week, online summer school in computational neuroscience

Neuromatch Academy (https://academy.neuromatch.io; (van Viegen et al., 2021)) was designed as an online summer school to cover the basics of computational neuroscience in three weeks. The materials cover dominant and emerging computational neuroscience tools, how they complement one another, and specifically focus on how they can help us to better understand how the brain functions. An original component of the materials is its focus on modeling choices, i.e. how do we choose the right approach, how do we build models, and how can we evaluate models to determine if they provide real (meaningful) insight. This meta-modeling component of the instructional materials asks what questions can be answered by different techniques, and how to apply them meaningfully to get insight about brain function