Disparities in arteriovenous fistula placement in older hemodialysis patients

The benefits of an arteriovenous fistula (AVF) as the preferred vascular access for hemodialysis have been clearly demonstrated. However, only about 20% of patients in the United States initiate hemodialysis with an AVF. In this study, we assessed whether disparities exist in the type of first hemodialysis access placed prior to dialysis start (rather than that used at dialysis initiation), to detect whether certain disadvantaged groups might have lower likelihood of AVF placement. Study cohort of 118,767 incident hemodialysis patients ≥67 years of age (1/2005–12/2008) derived from the United States Renal Data System was linked with Medicare claims data to identify the type of initial access placed predialysis. We used logistic regression model with outcome being the initial predialysis placement of an AVF as opposed to an arteriovenous graft or a central venous catheter. Increasing age, female sex, black race, lower body mass index, urban location, certain comorbidities, and shorter pre–end‐stage renal disease nephrology care are all associated with a significantly lower likelihood of AVF placement as initial access predialysis. Our study suggests the presence of significant disparities in the placement of an AVF as initial hemodialysis vascular access. We suggest that additional attention should be paid to these patient groups to improve disparities by patient education, earlier referral, and close follow‐up.     

Surface Supported Gold–Organic Hybrids: On‐Surface Synthesis and Surface Directed Orientation

The surface‐assisted synthesis of gold–organic hybrids on Au (111) and Au (100) surfaces is repotred by thermally initiated dehalogenation of chloro‐substituted perylene‐3,4,9,10‐tetracarboxylic acid bisimides (PBIs). Structures and surface‐directed alignment of the Au–PBI chains are investigated by scanning tunnelling microscopy in ultra high vacuum conditions. Using dichloro‐PBI as a model system, the mechanism for the formation of Au–PBI dimer is revealed with scanning tunnelling microscopy studies and density functional theory calculations. A PBI radical generated from the homolytic C‐Cl bond dissociation can covalently bind a surface gold atom and partially pull it out of the surface to form stable PBI‐Au hybrid species, which also gives rise to the surface‐directed alignment of the Au–PBI chains on reconstructed Au (100) surfaces.     

Chemically Tailoring Coal to Fluorescent Carbon Dots with Tuned Size and Their Capacity for Cu(II) Detection

The desired control of size, structure, and optical properties of fluorescent carbon dots (CDs) is critical for understanding the fluorescence mechanism and exploring their potential application. Herein, a top‐down strategy to chemically tailor the inexpensive coal to fluorescent CDs by a combined method of carbonization and acidic oxidation etching is reported. The size and optical properties of the as‐made CDs are tuned by controlling the structures of graphitic crystallites in the starting precursor. The coal‐derived CDs exhibit two different distinctive emission modes, where the intensity of the short‐wavelength emission is significantly enhanced by partial reduction treatment. The evolution of the electronic structure and the surface states analysis show that two different types of fluorescence centers, nano‐sized sp² carbon domains and surface defects, are responsible for the observed emission characteristics. The reduced CDs are demonstrated as an effective fluorescent sensing material for label‐free and selective detection of Cu(II) ions with a detection limit as low as 2.0 nm , showing a great promise for real‐world sensor applications.