History and Current State of Neurosurgery in the Gambia.

BACKGROUND: Despite global efforts to improve surgical care access, many low- and middle-income countries, especially in neurosurgery, face significant shortages. The Gambia exemplifies this, with only 1 fully qualified neurosurgeon serving its population of 2.5 million people. This scarcity results in higher morbidity and mortality. OBJECTIVE: We aim to document the history and current state of neurosurgery in the Gambia to raise awareness and promote neurosurgery development. METHODS: The study reviews the Gambia's health care system, infrastructure, neurosurgical history, workforce, disease burden, and progress, with information derived from reference sources as well as author experience and interviews with key partners in Gambian health care. RESULTS: Neurosurgery in the Gambia began in the 1970s, facing constraints due to competing health care demands. Significant progress occurred much later in the early 2010s, marked by the initiation of Banjul Neuro Missions and the establishment of a dedicated neurosurgery unit. We report significant progress with neurosurgical interventions in the past few years showcasing the unit's dedication to advancing neurosurgical care in the Gambia. However, challenges persist, including a lack of trained neurosurgeons, equipment shortages such as ventilators and diagnostic imaging. Financial barriers for patients, particularly related to the costs of computer tomography scans, pose significant hurdles, impacting the timely diagnosis and intervention for neurological conditions. CONCLUSIONS: Neurosurgery in the Gambia is progressing, but challenges like equipment scarcity hinder further progress. We emphasize the need for addressing cost barriers, improving infrastructure, and fostering research. Engaging the government and international collaborations are vital for sustained development in Gambian neurosurgery.

Atomic Layer Deposition of Cu Electrocatalysts on Gas Diffusion Electrodes for CO2 Reduction.

Electrochemical reduction of CO2 using Cu catalysts enables the synthesis of C2+ products including C2H4 and C2H5OH. In this study, Cu catalysts were fabricated using plasma-enhanced atomic layer deposition (PEALD), achieving conformal deposition of catalysts throughout 3-D gas diffusion electrode (GDE) substrates while maintaining tunable control of Cu nanoparticle size and areal loading. The electrochemical CO2 reduction at the Cu surface yielded a total Faradaic efficiency (FE) > 75% for C2+ products. Parasitic hydrogen evolution was minimized to a FE of ∼10%, and a selectivity of 42.2% FE for C2H4 was demonstrated. Compared to a line-of-sight physical vapor deposition method, PEALD Cu catalysts show significant suppression of C1 products compared to C2+, which is associated with improved control of catalyst morphology and conformality within the porous GDE substrate. Finally, PEALD Cu catalysts demonstrated a stable performance for 15 h with minimal reduction in the C2H4 production rate.

Competing ferro- and antiferromagnetic exchange drives shape-selective [Formula: see text] nanomagnetism.

We have synthesized three different shapes of [Formula: see text] nanoparticles to investigate the relationships between the surface Co[Formula: see text] and Co[Formula: see text] bonding quantified by exploiting the known exposed surface planes, terminations, and coordiations of [Formula: see text] nanoparticle spheres, cubes and plates. Subsequently this information is related to the unusual behaviour observed in the magnetism. The competition of exchange interactions at the surface provides the mechanism for different behaviours in the shapes. The cubes display weakened antiferromagnetic interactions in the form of a spin-flop that occurs at the surface, while the plates show distinct ferromagnetic behaviour due to the strong competition between the interactions. We elucidate the spin properties which are highly sensitive to bonding and crystal field environments. This work provides a new window into the mechanisms behind surface magnetism.

Unsupervised discovery of solid-state lithium ion conductors.

Although machine learning has gained great interest in the discovery of functional materials, the advancement of reliable models is impeded by the scarcity of available materials property data. Here we propose and demonstrate a distinctive approach for materials discovery using unsupervised learning, which does not require labeled data and thus alleviates the data scarcity challenge. Using solid-state Li-ion conductors as a model problem, unsupervised materials discovery utilizes a limited quantity of conductivity data to prioritize a candidate list from a wide range of Li-containing materials for further accurate screening. Our unsupervised learning scheme discovers 16 new fast Li-conductors with conductivities of 10-4-10-1 S cm-1 predicted in ab initio molecular dynamics simulations. These compounds have structures and chemistries distinct to known systems, demonstrating the capability of unsupervised learning for discovering materials over a wide materials space with limited property data.

Intratumoral Adaptive Immunosuppression and Type 17 Immunity in Mismatch Repair Proficient Colorectal Tumors.

PURPOSE: Approximately 10% of patients with mismatch repair-proficient (MMRp) colorectal cancer showed clinical benefit to anti-PD-1 monotherapy (NCT01876511). We sought to identify biomarkers that delineate patients with immunoreactive colorectal cancer and to explore new combinatorial immunotherapy strategies that can impact MMRp colorectal cancer. EXPERIMENTAL DESIGN: We compared the expression of 44 selected immune-related genes in the primary colon tumor of 19 patients with metastatic colorectal cancer (mCRC) who responded (n = 13) versus those who did not (n = 6) to anti-PD-1 therapy (NCT01876511). We define a 10 gene-based immune signature that could distinguish responder from nonresponder. Resected colon specimens (n = 14) were used to validate the association of the predicted status (responder and nonresponder) with the immune-related gene expression, the phenotype, and the function of tumor-infiltrating lymphocytes freshly isolated from the same tumors. RESULTS: Although both IL17Low and IL17High immunoreactive MMRp colorectal cancers are associated with intratumor correlates of adaptive immunosuppression (CD8/IFNγ and PD-L1/IDO1 colocalization), only IL17Low MMRp tumors (3/14) have a tumor immune microenvironment (TiME) that resembles the TiME in primary colon tumors of patients with mCRC responsive to anti-PD-1 treatment. CONCLUSIONS: The detection of a preexisting antitumor immune response in MMRp colorectal cancer (immunoreactive MMRp colorectal cancer) is not sufficient to predict a clinical benefit to T-cell checkpoint inhibitors. Intratumoral IL17-mediated signaling may preclude responses to immunotherapy. Drugs targeting the IL17 signaling pathway are available in clinic, and their combination with T-cell checkpoint inhibitors could improve colorectal cancer immunotherapy.See related commentary by Willis et al., p. 5185.

Predicting NOx Catalysis by Quantifying Ce3+ from Surface and Lattice Oxygen.

Our work introduces a novel technique based on the magnetic response of Ce3+ and molecular oxygen adsorbed on the surface of nanoceria and ceria-based catalysts that quantifies the number and type of defects and demonstrates that this information is the missing link that finally enables predictive design of NOx catalysis in ceria-based systems. The new insights into ceria catalysis are enabled by quantifying the above for different ceria nanoparticle shapes (i.e., surface terminations) and O2 partial pressure. We used ceria nanorods, cubes, and spheres and evaluated them for catalytic reduction of NO by CO. We then demonstrated the quantitative prediction of the reactivity of nanomaterials via their magnetism in different atmospheric environments. We find that the observed enhancement of reactivity for ceria nanocubes and nanorods is not directly due to improved reactivity on those surface terminations but rather due to the increased ease of generating lattice defects in these materials. Finally, we demonstrate that the method is equally applicable to highly topical and industrially relevant ceria mixed oxides, using nanoscale alumina-supported ceria as a representative case-a most ill-defined catalyst. Because the total oxide surface is a mixture of active ceria and inactive support and ceria is not likely present as crystallographically well-defined phases, reactivity does not easily scale with surface area or a surface termination. The key parameter to design efficient NO reduction in ceria-based catalysts is knowing and controlling the surface localized excess Ce3+ ion areal density.

Monitoring surface metal oxide catalytic active sites with Raman spectroscopy.

The molecular aspect of the Raman vibrational selection rules allows for the molecular structural and reactivity determinations of metal oxide catalytic active sites in all types of oxide catalyst systems (supported metal oxides, zeolites, layered hydroxides, polyoxometalates (POMs), bulk pure metal oxides, bulk mixed oxides and mixed oxide solid solutions). The molecular structural and reactivity determinations of metal oxide catalytic active sites are greatly facilitated by the use of isotopically labeled molecules. The ability of Raman spectroscopy to (1) operate in all phases (liquid, solid, gas and their mixtures), (2) operate over a very wide temperature (-273 to >1000 °C) and pressure (UHV to ≫100 atm) range, and (3) provide molecular level information about metal oxides makes Raman spectroscopy the most informative characterization technique for understanding the molecular structure and surface chemistry of the catalytic active sites present in metal oxide heterogeneous catalysts. The recent use of hyphenated Raman spectroscopy instrumentation (e.g., Raman-IR, Raman-UV-vis, Raman-EPR) and the operando Raman spectroscopy methodology (e.g., Raman-MS and Raman-GC) is allowing for the establishment of direct structure-activity/selectivity relationships that will have a significant impact on catalysis science in this decade. Consequently, this critical review will show the growth in the use of Raman spectroscopy in heterogeneous catalysis research, for metal oxides as well as metals, is poised to continue to exponentially grow in the coming years (173 references).