Surface Chemistry of a Halogenated Borazine: From Supramolecular Assemblies to a Random Covalent BN-Substituted Carbon Network.

The on-surface synthesis strategy has emerged as a promising route for fabricating well-defined two-dimensional (2D) BN-substituted carbon nanomaterials with tunable electronic properties. This approach relies on specially designed precursors and requires a thorough understanding of the on-surface reaction pathways. It promises precise structural control at the atomic scale, thus complementing chemical vapor deposition (CVD). In this study, we investigated a novel heteroatomic precursor, tetrabromoborazine, which incorporates a BN core and an OH group, on Ag(111) using low temperature scanning tunnelling microscopy/spectroscopy (LT-STM/STS) and X-ray photoelectron spectroscopy (XPS). Through sequential temperature-induced reactions involving dehalogenation and dehydrogenation, distinct tetrabromoborazine derivatives were produced as reaction intermediates, leading to the formation of specific self-assemblies. Notably, the resulting intricate supramolecular structures include a chiral kagomé lattice composed of molecular dimers exhibiting a unique electronic signature. The final product obtained was a random covalent carbon network with BN-substitution and embedded oxygen heteroatoms. Our study offers valuable insights into the significance of the structure and functionalization of BN precursors in temperature-induced on-surface reactions, which can help future rational precursor design. Additionally, it introduces complex surface architectures that offer a high areal density of borazine cores.

Solution vs On-Surface Synthesis of Peripherally Oxygen-Annulated Porphyrins through C-O Bond Formation.

This study investigates the synthesis of tetra- and octa-O-fused porphyrinoids employing an oxidative O-annulation approach through C-H activation. Despite encountering challenges such as overoxidation and instability in conventional solution protocols, successful synthesis was achieved on Au(111) surfaces under ultra-high vacuum (UHV) conditions. X-ray photoelectron spectroscopy, scanning tunneling microscopy, and non-contact atomic force microscopy elucidated the preferential formation of pyran moieties via C-O bond formation and subsequent self-assembly driven by C-H∙∙∙O interactions. Furthermore, the O-annulation process was found to reduce the HOMO-LUMO gap by lifting the HOMO energy level, with the effect rising upon increasing the number of embedded O-atoms.

Stripe-Like hBN Monolayer Template for Self-Assembly and Alignment of Pentacene Molecules.

Metallic surfaces with unidirectional anisotropy are often used to guide the self-assembly of organic molecules along a particular direction. Such supports thus offer an avenue for the fabrication of hybrid organic-metal interfaces with tailored morphology and precise elemental composition. Nonetheless, such control often comes at the expense of detrimental interfacial interactions that might quench the pristine properties of molecules. Here, hexagonal boron nitride grown on Ir(100) is introduced as a robust platform with several coexisting 1D stripe-like moiré superstructures that effectively guide unidirectional self-assemblies of pentacene molecules, concomitantly preserving their pristine electronic properties. In particular, highly-aligned longitudinal arrays of equally-oriented molecules are formed along two perpendicular directions, as demonstrated by comprehensive scanning tunneling microscopy and photoemission characterization performed at the local and non-local scale, respectively. The functionality of the template is demonstrated by photoemission tomography, a surface-averaging technique requiring a high degree of orientational order of the probed molecules. The successful identification of pentacene's pristine frontier orbitals underlines that the template induces excellent long-range molecular ordering via weak interactions, preventing charge transfer.

Borophenes made easy.

To date, the scalable synthesis of elemental two-dimensional materials beyond graphene still remains elusive. Here, we introduce a versatile chemical vapor deposition (CVD) method to grow borophenes, as well as borophene heterostructures, by selectively using diborane originating from traceable byproducts of borazine. Specifically, metallic borophene polymorphs were successfully synthesized on Ir(111) and Cu(111) single-crystal substrates and conjointly with insulating hexagonal boron nitride (hBN) to form atomically precise lateral borophene-hBN interfaces or vertical van der Waals heterostructures. Thereby, borophene is protected from immediate oxidation by a single hBN overlayer. The ability to synthesize high-quality borophenes with large single-crystalline domains in the micrometer scale by a straight-forward CVD approach opens up opportunities for the study of their fundamental properties and for device incorporation.

Molecular Approach for Engineering Interfacial Interactions in Magnetic/Topological Insulator Heterostructures.

Controlling interfacial interactions in magnetic/topological insulator heterostructures is a major challenge for the emergence of novel spin-dependent electronic phenomena. As for any rational design of heterostructures that rely on proximity effects, one should ideally retain the overall properties of each component while tuning interactions at the interface. However, in most inorganic interfaces, interactions are too strong, consequently perturbing, and even quenching, both the magnetic moment and the topological surface states at each side of the interface. Here, we show that these properties can be preserved using ligand chemistry to tune the interaction of magnetic ions with the surface states. By depositing Co-based porphyrin and phthalocyanine monolayers on the surface of Bi2Te3 thin films, robust interfaces are formed that preserve undoped topological surface states as well as the pristine magnetic moment of the divalent Co ions. The selected ligands allow us to tune the interfacial hybridization within this weak interaction regime. These results, which are in stark contrast with the observed suppression of the surface state at the first quintuple layer of Bi2Se3 induced by the interaction with Co phthalocyanines, demonstrate the capability of planar metal-organic molecules to span interactions from the strong to the weak limit.

Disfunción del catéter de diálisis peritoneal por atrapamiento de la trompa de Falopio / Disfunction of peritoneal dialysis catheter caused by Fallopian tube entrapment

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Monthly CERA treatment maintains stable hemoglobin levels in routine clinical practice of peritoneal dialysis patients.

Data on routine use of continuous erythropoietin receptor activator (CERA) in peritoneal dialysis patients are scarce. This study aimed to assess the efficacy of CERA administered once monthly in maintaining stable Hb levels in patients on peritoneal dialysis under routine medical practice. This was a 12-month, observational, prospective and multicenter study. A total of 83 patients with anemia secondary to chronic kidney disease (CKD) on peritoneal dialysis for more than 3 months, on once-monthly subcutaneous CERA treatment, were followed up over a period of 1 year. Efficacy evaluation included Hb levels, mean time in which the Hb level was maintained within target range, CERA doses and number of dose changes. Median Hb level (interquartile range [IQR]) remained stable during the evaluation period [11.8 ± 1.4 g/dL at baseline, 11.8 ± 1.4 g/dL at month 6 and 11.8 ± 1.5 g/dL at month 12 (p > 0.05)]. The median (IQR) time of Hb level maintained within target range (11-13 mg/dL) was 6 (4-10) months. Ferritin, transferrin saturation index, and Fe were also stable and well maintained during the 12 months (p > 0.05). CERA mean dose (SD) was [115.4 (56.2) µg baseline; 117.2 (58.5) µg 6 months; 126.0 (65.9) µg 12 months (p = 0.127)]. The mean number of CERA dose changes per patient during the study was 1.6 (SD 1.3). Serious adverse events were not related to CERA treatment. The results suggest that once-monthly CERA successfully corrects anemia and maintains stable Hb levels within the recommended target range on peritoneal dialysis under routine medical practice.

Dermatitis exfoliativa generalizada por eritropoyetina / Generalized exfoliative dermatitis due to erythropoietin

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