Assembly, Structure, and Reactivity of Cu\u3csub\u3e4\u3c/sub\u3eS and Cu\u3csub\u3e3\u3c/sub\u3eS Models for the Nitrous Oxide Reductase Active Site, Cu\u3csub\u3eZ\u3c/sub\u3e*

Bridging diphosphine ligands were used to facilitate the assembly of copper clusters with single sulfur atom bridges that model the structure of the CuZ* active site of nitrous oxide reductase. Using bis(diphenylphosphino)amine (dppa), a [CuI4(μ4-S)] cluster with N–H hydrogen bond donors in the secondary coordination sphere was assembled. Solvent and anion guests were found docking to the N–H sites in the solid state and in the solution phase, highlighting a kinetically viable pathway for substrate introduction to the inorganic core. Using bis(dicyclohexylphosphino)methane (dcpm), a [CuI3(μ3-S)] cluster was assembled preferentially. Both complexes exhibited reversible oxidation events in their cyclic voltammograms, making them functionally relevant to the CuZ* active site that is capable of catalyzing a multielectron redox transformation, unlike the previously known [CuI4(μ4-S)] complex from Yam and co-workers supported by bis(diphenylphosphino)methane (dppm). The dppa-supported [CuI4(μ4-S)] cluster reacted with N3–, a linear triatomic substrate isoelectronic to N2O, in preference to NO2–, a bent triatomic. This [CuI4(μ4-S)] cluster also bound I–, a known inhibitor of CuZ*. Consistent with previous observations for nitrous oxide reductase, the tetracopper model complex bound the I– inhibitor much more strongly and rapidly than the substrate isoelectronic to N2O, producing unreactive μ3-iodide clusters including a [Cu3(μ3-S)(μ3-I)] complex related to the [Cu4(μ4-S)(μ2-I)] form of the inhibited enzyme

A Cu\u3csub\u3e4\u3c/sub\u3eS Model for the Nitrous Oxide Reductase Active Sites Supported Only by Nitrogen Ligands

To model the (His)7Cu4Sn (n = 1 or 2) active sites of nitrous oxide reductase, the first Cu4(μ4-S) cluster supported only by nitrogen donors has been prepared using amidinate supporting ligands. Structural, magnetic, spectroscopic, and computational characterization is reported. Electrochemical data indicates that the 2-hole model complex can be reduced reversibly to the 1-hole state and irreversibly to the fully reduced state

A One-Hole Cu\u3csub\u3e4\u3c/sub\u3eS Cluster with N\u3csub\u3e2\u3c/sub\u3eO Reductase Activity: A Structural and Functional Model for Cu\u3csub\u3eZ\u3c/sub\u3e

During bacterial denitrification, two-electron reduction of N2O occurs at a [Cu4(μ4-S)] catalytic site (CuZ*) embedded within the nitrous oxide reductase (N2OR) enzyme. In this Communication, an amidinate-supported [Cu4(μ4-S)] model cluster in its one-hole (S = 1/2) redox state is thoroughly characterized. Along with its two-hole redox partner and fully reduced clusters reported previously, the new species completes the two-electron redox series of [Cu4(μ4-S)] model complexes with catalytically relevant oxidation states for the first time. More importantly, N2O is reduced by the one-hole cluster to produce N2 and the two-hole cluster, thereby completing a closed cycle for N2O reduction. Not only is the title complex thus the best structural model for CuZ* to date, but it also serves as a functional CuZ* mimic

GPU-Based Optimization of a Free-Viewpoint Video System

We present a method for optimizing the reconstruction and rendering of 3D objects from multiple images by utilizing the latest features of consumer-level graphics hardware based on shader model 4.0. We accelerate visual hull reconstruction by rewriting a shape-from-silhouette algorithm to execute on the GPU's parallel architecture. Rendering a is optimized through the application of geometry shaders to generate billboarding microfacets textured with captured images. We also present a method for handling occlusion in the camera selection process that is optimized for execution on the GPU. Execution time is further improved by rendering intermediate results directly to texture to minimize the number of data transfers between graphics and main memory. We show our GPU based system to be significantly more efficient than a purely CPU-based approach, due to the parallel nature of the GPU, while maintaining graphical quality

Utilization of ancillary studies in the cytologic diagnosis of respiratory lesions: The papanicolaou society of cytopathology consensus recommendations for respiratory cytology

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134863/1/dc23549.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134863/2/dc23549_am.pd

Clinical Laboratory Testing Practices in Diffuse Gliomas Prior to Publication of 2021 World Health Organization Classification of Central Nervous System Tumors

CONTEXT.—: Integration of molecular data into glioma classification supports diagnostic, prognostic, and therapeutic decision-making; however, testing practices for these informative biomarkers in clinical laboratories remain unclear. OBJECTIVE.—: To examine the prevalence of molecular testing for clinically relevant biomarkers in adult and pediatric gliomas through review of a College of American Pathologists proficiency testing survey prior to the release of the 2021 World Health Organization Classification of Central Nervous System Tumors. DESIGN.—: College of American Pathologists proficiency testing 2020 survey results from 96 laboratories performing molecular testing for diffuse gliomas were used to determine the use of testing for molecular biomarkers in gliomas. RESULTS.—: The data provide perspective into the testing practices for diffuse gliomas from a broad group of clinical laboratories in 2020. More than 98% of participating laboratories perform testing for glioma biomarkers recognized as diagnostic for specific subtypes, including IDH. More than 60% of laboratories also use molecular markers to differentiate between astrocytic and oligodendroglial lineage tumors, with some laboratories providing more comprehensive analyses, including prognostic biomarkers, such as CDKN2A/B homozygous deletions. Almost all laboratories test for MGMT promoter methylation to identify patients with an increased likelihood of responding to temozolomide. CONCLUSIONS.—: These findings highlight the state of molecular testing in 2020 for the diagnosis and classification of diffuse gliomas at large academic medical centers. The findings show that comprehensive molecular testing is not universal across clinical laboratories and highlight the gaps between laboratory practices in 2020 and the recommendations in the 2021 World Health Organization Classification of Central Nervous System Tumors