Exfoliated Nanocomposites Based on Polyaniline and Tungsten Disulfide

Nanocomposite materials consisting of polyaniline (PANI) and exfoliated WS2 were synthesized. The WS2 was prepared by reacting tungstic acid with thiourea at 500°C under nitrogen flow. Samples were prepared with a WS2 content of 1, 5, 7.5, 10, 12.5, 15, 20, 37, and 64% by mass. An improvement in the electronic conductivity value of the PANI was observed through the incorporation of exfoliated WS2. The electronic conductivity of PANI-15%WS2 was 24.5 S/cm, an eightfold increase when compared to pure PANI. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) provided evidence that the nanocomposites are in an exfoliated state. XRD and TEM showed that the nanocomposites were completely amorphous, suggesting lack of structural order in these materials, while their EPR signals were considerably narrower compared to pure PANI, indicating the formation of genuine exfoliated systems. Furthermore, our research showed that WS2 can be used as a filler to improve activation energy of decomposition of the polymer. By using the Ozawa method, we studied the decomposition kinetics for the nanocomposites, as well as for the pure polymer. The activation energy for the decomposition of pure PANI was found to be 131.2 kJ/mol. Increasing the amount of WS2 to 12.5% in the PANI increases the activation energy of decomposition to 165.4 kJ/mol, an enhancement of 34.2 kJ/mol over the pure polymer

Expertise in surgical neuro-oncology. Results of a survey by the EANS neuro-oncology section

Introduction: Technical advances and the increasing role of interdisciplinary decision-making may warrant formal definitions of expertise in surgical neuro-oncology. Research question: The EANS Neuro-oncology Section felt that a survey detailing the European neurosurgical perspective on the concept of expertise in surgical neuro-oncology might be helpful. Material and methods: The EANS Neuro-oncology Section panel developed an online survey asking questions regarding criteria for expertise in neuro-oncological surgery and sent it to all individual EANS members. Results: Our questionnaire was completed by 251 respondents (consultants: 80.1%) from 42 countries. 67.7% would accept a lifetime caseload of >200 cases and 86.7% an annual caseload of >50 as evidence of neuro-oncological surgical expertise. A majority felt that surgeons who do not treat children (56.2%), do not have experience with spinal fusion (78.1%) or peripheral nerve tumors (71.7%) may still be considered experts. Majorities believed that expertise requires the use of skull-base approaches (85.8%), intraoperative monitoring (83.4%), awake craniotomies (77.3%), and neuro-endoscopy (75.5%) as well as continuing education of at least 1/year (100.0%), a research background (80.0%) and teaching activities (78.7%), and formal interdisciplinary collaborations (e.g., tumor board: 93.0%). Academic vs. non-academic affiliation, career position, years of neurosurgical experience, country of practice, and primary clinical interest had a minor influence on the respondents’ opinions. Discussion and conclusion: Opinions among neurosurgeons regarding the characteristics and features of expertise in neuro-oncology vary surprisingly little. Large majorities favoring certain thresholds and qualitative criteria suggest a consensus definition might be possible

Complications of Intracranial Multimodal Monitoring for Neurocritical Care: A Systematic Review and Meta-Analysis.

Intracranial multimodal monitoring (iMMM) is increasingly used for neurocritical care. However, concerns arise regarding iMMM invasiveness considering limited evidence in its clinical significance and safety profile. We conducted a synthesis of evidence regarding complications associated with iMMM to delineate its safety profile. We performed a systematic review and meta-analysis (PROSPERO Registration Number: CRD42021225951) according to the Preferred Reporting Items for Systematic Review and Meta-Analysis and Peer Review of Electronic Search Strategies guidelines to retrieve evidence from studies reporting iMMM use in humans that mention related complications. We assessed risk of bias using the Newcastle-Ottawa Scale and funnel plots. The primary outcomes were iMMM complications. The secondary outcomes were putative risk factors. Of the 366 screened articles, 60 met the initial criteria and were further assessed by full-text reading. We included 22 studies involving 1206 patients and 1434 iMMM placements. Most investigators used a bolt system (85.9%) and a three-lumen device (68.8%), mainly inserting iMMM into the most injured hemisphere (77.9%). A total of 54 postoperative intracranial hemorrhages (pooled rate of 4%; 95% confidence interval [CI] 0-10%; I <sup>2</sup> 86%, p < 0.01 [random-effects model]) was reported, along with 46 misplacements (pooled rate of 6%; 95% CI 1-12%; I <sup>2</sup> 78%, p < 0.01) and 16 central nervous system infections (pooled rate of 0.43%; 95% CI 0-2%; I <sup>2</sup> 64%, p < 0.01). We found 6 system breakings, 18 intracranial bone fragments, and 5 cases of pneumocephalus. Currently, iMMM systems present a similar safety profile as intracranial devices commonly used in neurocritical care. Long-term outcomes of prospective studies will complete the benefit-risk assessment of iMMM in neurocritical care. Consensus-based reporting guidelines on iMMM use are needed to bolster future collaborative efforts

Kinetic Stabilization of the Sol–Gel State in Perovskites Enables Facile Processing of High-Efficiency Solar Cells

Perovskite solar cells increasingly feature mixed-halide mixed-cation compounds (FA1−x−yMAxCsyPbI3−zBrz) as photovoltaic absorbers, as they enable easier processing and improved stability. Here, the underlying reasons for ease of processing are revealed. It is found that halide and cation engineering leads to a systematic widening of the anti-solvent processing window for the fabrication of high-quality films and efficient solar cells. This window widens from seconds, in the case of single cation/halide systems (e.g., MAPbI3, FAPbI3, and FAPbBr3), to several minutes for mixed systems. In situ X-ray diffraction studies reveal that the processing window is closely related to the crystallization of the disordered sol–gel and to the number of crystalline byproducts; the processing window therefore depends directly on the precise cation/halide composition. Moreover, anti-solvent dripping is shown to promote the desired perovskite phase with careful formulation. The processing window of perovskite solar cells, as defined by the latest time the anti-solvent drip yields efficient solar cells, broadened with the increasing complexity of cation/halide content. This behavior is ascribed to kinetic stabilization of sol–gel state through cation/halide engineering. This provides guidelines for designing new formulations, aimed at formation of the perovskite phase, ultimately resulting in high-efficiency perovskite solar cells produced with ease and with high reproducibility

Multi-cation Synergy Suppresses Phase Segregation in Mixed-Halide Perovskites

Having recognized the potential of hybrid organic-inorganic perovskites solar cells, in recent years the photovoltaic community has shifted its focus away from efficiency improvements to simplifying the processing and improving the stability of devices. In this work, we utilize in situ and time-resolved X-ray scattering to track various phase evolutions during the perovskite film solidification to link the microstructure to the composition. In particular, we unravel the crucial roles of Cs+ and Rb+ in promoting the in situ formation of the perovskite phase prior to thermal annealing, thus preventing segregation of halides and cations. Our study points to a significant new guideline for designing mixed-halide mixed-cation perovskites: the sol-gel formulation must possess the ability to convert directly into the targeted perovskite phase without transitioning through compositionally distinct intermediate phases in order to minimize halide segregation and yield-homogenized films

Management of cranial deformity following ventricular shunting

Purpose: Ventricular shunt-induced craniosynostosis is a widely recognised cause of secondary craniosynostosis. We reviewed the management and long-term outcome of the cases of cranial deformity post cerebrospinal fluid shunting in our unit and compared these with previously published series. Methods: The Australian Craniofacial Unit and Department of Neurosurgery database was searched to identify cases of ventricular shunt-induced cranial deformity and a case note review was undertaken. Results: Eight cases were identified, and all were shunted within 6 months of birth. Our patients required shunting with a low pressure valve for hydrocephalus secondary to either aqueduct stenosis or intraventricular haemorrhage. The diagnosis was made following computed tomography (CT) three-dimensional surface reconstruction of the skull. Two cases of confirmed suture fusion were treated with cranial vault remodelling and programmable shunt insertion. In six cases, the sutures were not completely fused on the CT images despite a scaphocephalic head shape. These patients were managed conservatively with close monitoring. Conclusion: Cranial vault remodelling together with insertion of programmable shunt valve is indicated in CT confirmed cases of secondary craniosynostosis.X. Doorenbosch, C. J. Molloy, D. J. David, S. Santoreneos and P. J. Anderso