The use of the sodium fluorescein and YELLOW 560 nm filter for the resection of pediatric posterior fossa lesions

Purpose This study aimed to verify the feasibility, safety, and benefit of using fluorescein sodium (FL) and a YELLOW 560 nm filter in posterior fossa tumors in children. Methods All cases of pediatric posterior fossa tumors that have undergone surgery using fluorescein (2018–2022) have been included and were examined retrospectively. In those cases where resection of the tumor was planned, a blinded neuroradiologist distinguished gross total resection and subtotal resection according to the postoperative MRI findings. The surgical report and medical files were reviewed regarding the intraoperative staining grade and adverse events. The grade of fluorescent staining of the targeted lesion was assessed as described in the surgical reports. The screening was conducted for any reference to the degree of fluorescent staining: “intense,” “medium,” “slight,” and “no staining.” Results 19 cases have been included. In 14 cases, a complete resection was initially intended. In 11 of these cases, a gross total resection could be achieved (78.6%). Staining was described as intense in most cases (58.8%). Except for yellow-colored urine, no side effects obviously related to FL were found throughout the observation period. Conclusion In combination with a specific filter, FL is a reliable, safe, and feasible tool in posterior fossa surgery in children

Multi-dimensional modeling and simulation of semiconductor nanophotonic devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources

A Disease-causing Mutation Illuminates the Protein Membrane Topology of the Kidney-expressed Prohibitin Homology ( PHB) Domain Protein Podocin

Background: Mutations in the stomatin family protein podocin are the most common genetic cause of proteinuria. Results: A conserved proline residue of podocin is essential for its membrane topology. Conclusion: This study confirms a hairpin-like structure of the membrane-attached PHB domain protein and its significance for cholesterol recruitment. Significance: Podocin(P118L) elucidates the pathogenic implication in kidney disease and identifies a novel family of PHB domain proteins. Mutations in the NPHS2 gene are a major cause of steroid-resistant nephrotic syndrome, a severe human kidney disorder. The NPHS2 gene product podocin is a key component of the slit diaphragm cell junction at the kidney filtration barrier and part of a multiprotein-lipid supercomplex. A similar complex with the podocin ortholog MEC-2 is required for touch sensation in Caenorhabditis elegans. Although podocin and MEC-2 are membrane-associated proteins with a predicted hairpin-like structure and amino and carboxyl termini facing the cytoplasm, this membrane topology has not been convincingly confirmed. One particular mutation that causes kidney disease in humans (podocin(P118L)) has also been identified in C. elegans in genetic screens for touch insensitivity (MEC-2(P134S)). Here we show that both mutant proteins, in contrast to the wild-type variants, are N-glycosylated because of the fact that the mutant C termini project extracellularly. Podocin(P118L) and MEC-2(P134S) did not fractionate in detergent-resistant membrane domains. Moreover, mutant podocin failed to activate the ion channel TRPC6, which is part of the multiprotein-lipid supercomplex, indicative of the fact that cholesterol recruitment to the ion channels, an intrinsic function of both proteins, requires C termini facing the cytoplasmic leaflet of the plasma membrane. Taken together, this study demonstrates that the carboxyl terminus of podocin/MEC-2 has to be placed at the inner leaflet of the plasma membrane to mediate cholesterol binding and contribute to ion channel activity, a prerequisite for mechanosensation and the integrity of the kidney filtration barrier

A multicenter cohort study of early complications after cranioplasty: results of the German Cranial Reconstruction Registry

OBJECTIVE Cranioplasty (CP) is a crucial procedure after decompressive craniectomy and has a significant impact on neurological improvement. Although CP is considered a standard neurosurgical procedure, inconsistent data on surgery-related complications after CP are available. To address this topic, the authors analyzed 502 patients in a prospective multicenter database (German Cranial Reconstruction Registry) with regard to early surgery-related complications. METHODS Early complications within 30 days, medical history, mortality rates, and neurological outcome at discharge according to the modified Rankin Scale (mRS) were evaluated. The primary endpoint was death or surgical revision within the first 30 days after CP. Independent factors for the occurrence of complications with or without surgical revision were identified using a logistic regression model. RESULTS Traumatic brain injury (TBI) and ischemic stroke were the most common underlying diagnoses that required CP. In 230 patients (45.8%), an autologous bone flap was utilized for CP; the most common engineered materials were titanium (80 patients [15.9%]), polyetheretherketone (57[11.4%]), and polymethylmethacrylate (57[11.4%]). Surgical revision was necessary in 45 patients (9.0%), and the overall mortality rate was 0.8% (4 patients). The cause of death was related to ischemia in 2 patients, diffuse intraparenchymal hemorrhage in 1 patient, and cardiac complications in 1 patient. The most frequent causes of surgical revision were epidural hematoma (40.0% of all revisions), new hydrocephalus (22.0%), and subdural hematoma (13.3%). Preoperatively increased mRS score (OR 1.46, 95% CI 1.08-1.97, p = 0.014) and American Society of Anesthesiologists Physical Status Classification System score (OR 2.89, 95% CI 1.42-5.89, p = 0.003) were independent predictors of surgical revision. Ischemic stroke, as the underlying diagnosis, was associated with a minor rate of revisions compared with TBI (OR 0.18, 95% CI 0.06-0.57, p = 0.004). CONCLUSIONS The authors have presented class II evidence-based data on surgery-related complications after CP and have identified specific preexisting risk factors. These results may provide additional guidance for optimized treatment of these patients

Multi-dimensional Modeling and Simulation of Semiconductor Nanophotonic Devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semi-classical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperatures. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources